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OPENING SESSION Hall F/G 07:30 – 8:20 Chair: Jeffrey L. Duerk, ISMRM President

7:30 Welcome and Awards Presentations

2008 LAUTERBUR LECTURE Hall F/G 08:20 – 9:00 Chair: Jeffrey L. Duerk, ISMRM President

8:20 The Origin of MRI in Physics - Curiosity, Serendipity and Inventions Herman Y. Carr Rutgers University, Piscataway, New Jersey, USA

PLENARY LECTURES: Diffusion Outside the Head Hall F/G 09:00-10:15 Chairs: Klaas Nicolay and Caroline Reinhold

9:00 1. Diffusion-Weighted MRI of Skeletal & Cardiac Muscle Bruce M. Damon1 1Vanderbilt University, Durham, North Carolina, USA

Water diffusion in cardiac and skeletal muscles is anisotropic. The structural basis for this finding lies in the greatly elongated cellular dimensions, the presence of longitudinally oriented intracellular protein filaments, and (in cardiac muscle) the existence of a layered sheet structure. Diffusion-tensor MRI is made technically challenging by factors such as intramuscular fat, low T2, and difficult-to-shim volumes. However, it is feasible and has been used to generate new insights into cardiac and skeletal muscle architecture and mechanics, microstructure, and damage.

9:25 2. Diffusion-Weighted MRI of the Kidneys: Beyond Morphology Harriet C. Thoeny1 1Inselspital, Bern, Switzerland

Diffusion-weighted MRI is a noninvasive imaging technique that provides information on diffusion and perfusion at the same time. Its application in abdominal organs despite considerably grown interest in recent years is still very challenging due its technical difficulties.Only recently, DW-MRI of the kidneys started to evolve. Most studies analyzed the feasibility and reproducibility of DW-MRI by using different technical approaches or were performed in experimental settings. However, only few studies were performed in patients (native and transplanted kidneys) showing promising results in several pathological conditions.

9:50 3. Whole Body Volumetric Diffusion-weighted Imaging (DWI) Taro Takahara1 1Tokai University School of Medicine, Kanagawa, Japan

Motion probing gradients (MPGs) only suppress incoherent motion as observed in diffusion study. Respiratory motion can be regarded as “coherent” motion during the short period in which the MPGs are applied. This implies that DWI can be performed even during free breathing at the expense of some image blurring. This concept is called “Diffusion weighted Whole body Imaging with Background body signal Suppression” (DWIBS) and allows volumetric DWI. It is useful to understand tumor distribution. Similarly, it can reveal peripheral nerves, providing a methodology called diffusion-weighted MR-neurography. Whole-body scanning can be done by merging image stacks taken in sequential locations.

Parallel Imaging Room 801 A/B 11:00-13:00 Chairs: Joseph V. Hajnal and Stefan T. Skare

11:00 4. Practical Considerations for GRAPPA-Accelerated Readout-Segmented EPI in Diffusion-Weighted Imaging Samantha J. Holdsworth1, Stefan Skare1, Rexford D. Newbould1, Anders Nordell2, Roland Bammer1 1Stanford University, Palo Alto, California , USA; 2Karolinska University Hospital, Stockholm, Sweden

Readout mosaic segmentation (RS-EPI) has been suggested as an alternative approach to EPI for high resolution diffusion-weighted imaging (DWI) with minimal geometric distortions. In this abstract, peripherally cardiac gated and non-gated RS-EPI-DW images are acquired with the use of parallel imaging. The methods used to phase correct and reconstruct the partial Fourier GRAPPA-accelerated RS-EPI-DW data are described. It is shown that patient handling can be simplified with the use of non-gated acquisitions and minimally-overlapping blinds. The efficient acquisition of high resolution RS-EPI images makes this sampling strategy a useful alternative to other navigated methods used for DW imaging.

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11:12 5. Auto-Calibrated Parallel Imaging Reconstruction Using K-Space Sparse Matrices (KSPA) Chunlei Liu1, Jian Zhang1, Michael E. Moseley1 1Stanford University, Stanford, California , USA

A non-iterative parallel imaging reconstruction algorithm that utilizes k-space sparse matrix (kSPA) was recently introduced for arbitrary sampling patterns. The kSPA algorithm computes a sparse reconstruction matrix in k-space. This algorithm was shown to be particularly useful for a wide range of applications including 3D imaging, functional MRI (fMRI), perfusion-weighted imaging, diffusion tensor imaging (DTI) and massive parallel imaging, where a large number of images have to be reconstructed. The original algorithm requires the acquisition of low-resolution coil sensitivity maps. We present an auto-calibrated kSPA algorithm for arbitrary trajectories that does not require the explicit estimation of coil sensitivities.

11:24 6. Whole-Heart Imaging Using Undersampled Radial Phase Encoding and a 32-Channel Cardiac Coil Redha Boubertakh1, 2, Philip G. Batchelor1, Sergio Uribe1, Thomas S. Sørensen2, Michael S. Hansen2, Reza S. Razavi1, Tobias Schaeffter1 1King's College London, London, UK; 2University College London, London, UK

We present a new 3D acquisition for whole-heart imaging that combines radial k-space phase encoding in the ky-kz plane and Cartesian readout sampling. Fully sampled data were acquired on a volunteer using a 32-channel cardiac coil. The raw data were undersampled offline with different acceleration factors (R = 8 and 12). The images were reconstructed using gridding and iterative SENSE techniques. When compared to the fully sampled volume, iterative SENSE provides good quality images where artifact levels are strongly reduced compared to gridding. This would lead to a significant decrease in the scan time.

11:36 7. Reconstruction of Undersampled Non-Cartesian Data Using GROG-Facilitated Random Blipped Phase Encoding Nicole Seiberlich1, Philipp Ehses1, Felix A. Breuer2, Martin Blaimer2, Peter M. Jakob1, 2, Mark A. Griswold3 1University of Wuerzburg, Wuerzburg, Germany; 2Research Center Magnetic Resonance Bavaria (MRB), Wuerzburg, Germany; 3University Hospitals of Cleveland, Cleveland, Ohio, USA

It has been shown that the Generalized Sampling Theorem of Papoulis can be exploited to reduce measurement time by acquiring points blipped in the phase encoding direction and applying a conjugate gradient (CG) reconstruction. Such a blipped trajectory can also be mimicked using a standard trajectory in conjunction with the GRAPPA Operator Gridder (GROG) to shift k-space points; a subsequent CG reconstruction results in an unaliased image even when the Nyquist criterion has not been met in all portions of k-space. The acceleration of in vivo radial, spiral, and rosette images is demonstrated using GROG to generate random blipped points.

11:48 8. Direct Virtual Coil (DVC) Reconstruction for Data-Driven Parallel Imaging Philip James Beatty1, Wei Sun2, Anja C. S. Brau1 1GE Healthcare, Menlo Park, California , USA; 2GE Healthcare, Waukesha, Wisconsin, USA

A method is proposed for improving the computational efficiency of data-driven parallel imaging reconstruction, while maintaining good image quality. The proposed method forgoes the computationally expensive ‘coil-by-coil’ approach introduced by GRAPPA in favor of directly synthesizing ‘virtual coil’ data. Results show that the proposed method is able to achieve similar SNR to coil-by-coil approaches and offers similar resiliency to phase cancellation artifacts, while reducing the data synthesis computation by a factor of 20X for 32-channel arrays and over 100X for 128-channel arrays.

12:00 9. Parallel Reconstruction Using Null Operations (PRUNO) Jian Zhang1, 2, Chunlei Liu1, Michael Moseley1 1Stanford University, Stanford, California , USA

A new GRAPPA based iterative Cartesian parallel reconstruction method is proposed which is called Parallel Reconstruction Using Null Operations (PRUNO). In PRUNO, some local null operators are applied on all k-space locations to formulate the reconstruction problem as linear equations. We also demonstrate that it can be solved efficiently and accurately with a conjugate gradient method. According to our preliminary simulation and in vivo results, PRUNO can be used to improve the accuracy of image reconstruction compared to GRAPPA, especially at high image acceleration rate. Besides, since we usually use merely small local operators in PRUNO, only a small number of ACS lines are required, independent of the exact reduction rate.

12:12 10. A General Formulation for Quantitative G-Factor Calculation in GRAPPA Reconstructions Felix A. Breuer1, Martin Blaimer1, Nicole Seiberlich2, Peter M. Jakob1, 2, Mark A. Griswold3 1Research Center Magnetic Resonance Bavaria, Würzburg, Germany; 2University of Würzburg, Würzburg, Germany; 3University Hospitals of Cleveland, Cleveland, USA

In this work, equivalent to the g-factor in SENSE reconstructions, a theoretical description for quantitative estimation of the noise enhancement in GRAPPA reconstructions is described. The Grappa g-factor is derived directly from the GRAPPA reconstruction weights. In addition, the procedure presented here allows the calculation of quantitative g-factor maps for both the uncombined and combined accelerated GRAPPA images.

12:24 11. A Prospective Error Measure for K-T SENSE Shaihan J. Malik1, Jo V. Hajnal1 1Hammersmith Hospital, Imperial College London, London, UK

In parallel imaging the 'g-factor' provides a vital prospective measure of noise amplification. For dynamic undersampled techniques such as k-t SENSE, in addition to typical noise amplification from parallel imaging, errors can arise from temporal filtering due to the prior information (training data). We define an analogous quantity to g termed gkt which includes both effects, and investigate its correlation with reconstruction error and its spatiotemporal distribution. Results from retrospectively undersampled cardiac images and numerical phantoms indicate that gkt is a useful tool for relative comparison between different undersample strategies given an object and receiver coil setup.

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12:36 12. Influence of Regularization on Noise Amplification in Iterative SENSE Reconstruction Holger Eggers1, Peter C. Mazurkewitz1 1Philips Research Europe, Hamburg, Germany

Results of previously performed statistical estimations of the noise amplification in non-Cartesian sensitivity encoding imaging with Monte Carlo simulations remain questionable due to their dependence on the number of iterations after which the reconstruction is stopped. In this work, the use of explicit regularization is advocated, and it is demonstrated to stabilize the convergence of the reconstruction and to virtually eliminate this dependence. Calculated maps of the noise amplification are thus rendered more reliable and better comparable between different sampling patterns. Potential advantages of non-Cartesian acquisitions, like more homogeneous and lower maximum noise amplification, are confirmed and substantiated with this approach.

12:48 13. SENSE Regularization Using Bregman Iterations Bo Liu1, Kevin F. King2, Michael C. Steckner3, Lei Ying1 1University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA; 2GE Healthcare, Waukesha, Wisconsin, USA; 3Toshiba Medical Research Institute USA, Inc., Cleveland, Ohio, USA

The ill-conditioning problem has been addressed by Tikhonov regularization inCartesian SENSE with some success. However, a high-quality regularization image is needed to preserve the details, and otherwise the reconstruction is overlysmooth. In this abstract, we propose a new regularization technique usingBregman iteration. Without any need for regularization images, the methoditeratively refine the total variation (TV) regularization such that theregularized image has more fine details than using TV regularization alone. The proposed method is shown to address the oversmooth problem in Tikhonov regularization and the blocky artifacts in TV regularization.

Methods & Applications of Molecular Imaging Room 718 A 11:00-13:00 Chairs: Eric T. Ahrens and Gregory M. Lanza

11:00 14. Time-Resolved Molecular Imaging of the “Angiogenic Switch” in Animal Models of Cancer Anne H. Schmieder1, Todd A. Williams1, John S. Allen1, Grace Hu1, Huiying Zhang1, Shelton D. Caruthers1, 2, Samuel A. Wickline1, Gregory M. Lanza1 1Washington University School of Medicine, St Louis, Missouri, USA; 2Philips Medical Systems, Andover, Massachusetts, USA

α v β3 targeted paramagnetic nanoparticles provide a powerful tool to noninvasively interrogate tumors and characterize angiogenesis. Time-resolved 3D neovascular maps illustrated the “angiogenic switch” between days 8 and 14 in the Vx2 tumor, revealing densely coalesced regions of neovasculature interspersed with a sparse reticular pattern of enhanced voxels. In contradistinction, angiogenesis in the MDA435 tumor model was minimal at 14 and 21 days. Characterization of tumor neovasculature could support individualized stratification of patients into anti-angiogenic based treatment regimens and their longitudinal monitoring.

11:12 15. Avidin-Induced Clearance of Non-Bound RGD-Biotin-Liposomes for Target-Specific MR Molecular Imaging of Tumor Angiogenesis Geralda A.F. van Tilborg1, Willem j.m. Mulder2, Chris P.M. Reutelingsperger3, Arjan W. Griffioen3, Daisy W.J. van der Schaft1, Gustav J. Strijkers1, Klaas Nicolay1 1Eindhoven University of Technology, Eindhoven, Netherlands; 2Mount Sinai School of Medicine, New York, USA; 3University of Maastricht, Maastricht, Netherlands

The α v β 3 integrin is strongly expressed in angiogenic vessels and has been used as a target for RGD-functionalized MR contrast agents to enable visualization of angiogenesis in vivo. Little difference in contrast enhancement between the targeted and the non-targeted control contrast agent was observed in the MR images, which was attributed to differences in the circulation half-life between both agents. This study shows that avidin-induced blood clearance can be used to investigate the relative contribution of target-associated and circulating non-bound contrast agent to the MRI contrast enhancement, which opens exciting opportunities for the improvement of MR molecular imaging protocols.

11:24 16. In-Vivo Assessments of Mucus Dynamics in the Lungs Using a Gd-Cy5.5-Bilabeled Contrast Agent François-Xavier Blé1, 2, Philipp Schmidt1, Rainer Kneuer1, Catherine Cannet1, Harry Karmouty-Quintana1, Stefan Zurbruegg1, Hans-Ulrich Gremlich1, Nicolau Beckmann1 1Novartis Institutes for BioMedical Research, Basel, Switzerland; 2University Louis Pasteur-Strasbourg-1, Illkirch, France

A Gd- and Cy5.5-bilabeled aminodextran contrast agent was developed with the aim of marking specifically the mucus in the lung. Administration of the contrast agent either as solution (BCR249) or powder (BCR250) led to a significant increase of signals in the rat lung 24 h after lipopolysaccharide (LPS). The signals remained increased for about 24 h after the probe administration. At this time point, near-infrared fluorescence (NIRF) imaging confirmed the presence of the contrast agent in the isolated lungs from the same animal, and histology revealed that BCR249/250 was bound specifically to mucus.

11:36 17. In Vivo Quantification of 19F Molecluar Imaging Agents with Improved Accuracy and Sensitivity Using Motion Correcting, Simultaneous 19F/1H Radial MRI Jochen Keupp1, Jürgen Rahmer1, Emily A. Waters2, Shelton D. Caruthers2, 3, Gregory M. Lanza2, Samuel A. Wickline2 1Philips Research Europe, Hamburg, Germany; 2Washington University, St. Louis, Missouri, USA; 3Philips Medical Systems, Andover, Massachusetts, USA

Simultaneous 19F/1H MRI has a high potential for precise anatomical location and quantification of fluorine labeled diagnostic or therapeutic agents. However, during the measurement time (10 minutes) which is necessary to detect targeted agents in vivo, physiological motion leads to signal blurring and systematic underestimation of concentrations. It is shown in a mouse model, that motion correction for 19F is feasible using the 1H signal in simultaneous radial image acquisitions (2D or 3D stack-of-stars). Statistical analysis of measurements with and without motion demonstrates the improvement for in vivo 19F signal quantification.

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11:48 18. A Three-Compartment T1-Relaxation Model for Intracellular Contrast Agents: Implications for Molecular MR Imaging Gustav Jacob Strijkers1, Sjoerd Hak1, Maarten B. Kok1, Charles S. Springer, Jr. 2, Klaas Nicolay1 1Eindhoven University of Technology, Eindhoven, Netherlands; 2Oregon Health & Science University, Portland, Oregon, USA

The goal of this work is to develop a model describing the effective longitudinal relaxation rate constant (R1) for H2O in three compartments experiencing possible exchange, and to apply this model to explain the effective R1 [CA]-dependence of internalized contrast agents into cells. The quenching of H2O R1 due to limited water exchange could be simulated and the model matched experimental in vitro data very well.

12:00 19. Four-Pool Modeling of Proton Exchange Processes in Biological Systems in the Presence of MRI-PARACEST Agents Alex Xuexin Li1, 2, Robert H.E. Hudson2, John Barrett1, Robert Bartha1, 2 1Robarts Research Institute, London, Canada; 2The University of Western Ontario, London, Canada

The inherent magnetization transfer from endogenous macromolecules significantly limits the detection sensitivity of current PARACEST agents. A four-pool model of the proton exchange processes in biological systems in the presence of a PARACEST contrast agent is presented based on the modified Bloch equations with exchange terms. The model was applied to estimate the bound water chemical shift and the transverse relaxation time of an agent-labeled (Eu3+-DOTAM-Gly-Phe) biological system consisting of Vero cells.

12:12 20. Microfabricated Magnetic Structures for Multi-Spectral Contrast Gary Zabow1, 2, Stephen Dodd1, John Moreland2, Alan Koretsky1 1National Institutes of Health, Bethesda, USA; 2National Institute of Standards and Technology, Boulder, USA

We demonstrate a new form of multi-spectral MRI contrast agent constructed via microfabrication instead of traditional chemical synthesis. The spectral shifts of these agents can be tailored through fabrication process parameter control and, even for small MRI fields, can span a range far exceeding that of chemical exchange agents. We show how such micro-engineered structures allow increased functionality and sensitivity compared to existing chemically-synthesized contrast agents.

12:24 21. Inorganic Core HDL Applied for Macrophage Imaging David Peter Cormode1, Torjus Skajaa1, Mark E. Lobatto1, Karen C. Briley-Saebo1, Alessandra Barazza1, 2, Edward A. Fisher2, Zahi Adel Fayad1, Willem J. Mulder1 1Mount Sinai School of Medicine, New York, USA; 2New York University, New York, USA

Imaging atherosclerosis is a topic of great current interest and HDL is naturally targeted to this disease. We have replaced the triglyceride/cholesterol ester core of HDL with inorganic nanoparticles such as gold for CT, iron oxide for MRI or quantum dots for optical imaging, forming novel molecular imaging contrast agents for atherosclerosis. Rhodamine and gadolinium were incorporated into the phospholipid coating for the gold and quantum dots, creating multifunctional particles. We have incubated these particles with macrophage cells and shown uptake by confocal microscopy, TEM, MRI and CT imaging. In addition, we have carried out preliminary in vivo imaging studies.

12:36 22. In Vivo MR Imaging of Acute Thrombus Formation Using a Bimodal Contrast Agent Robbert-Jan J.H.M. Miserus1, 2, Lenneke Prinzen2, M V. Herias1, Tilman M. Hackeng2, Anouk Dirksen2, Wencke Adriaens2, Marc A.M.J. van Zandvoort2, Marc B.I. Lobbes1, Mat J.A.P. Daemen1, Jos J.M.A. van Engelshoven1, Sylvia Heeneman1, Marianne Eline Kooi1 1Maastricht University Hospital, Maastricht, Netherlands; 2Maastricht University, Maastricht, Netherlands

Thrombus formation plays a central role in several cardiovascular diseases. Since the resistance of thrombi against fibrinolytic therapy is achieved within hours, early detection of thrombus formation is vital. During these early stages of thrombus formation, activated factor XIII cross-links α 2-antiplasmin to the fibrin network. A bimodal α 2-antiplasmin-based contrast agent (CA) and a non-specific bimodal control CA were synthesized. A feasibility study was performed in vitro and in vivo which showed that the α 2-antiplasmin-based bimodal CA enables in vivo MR imaging of acute thrombus formation. Specific binding of this CA to the fibrin network was confirmed by TPLSM.

12:48 23. MntR, an MRI Reporter Provides Cellular T1 Contrast Without Mn Supplementation Benjamin B. Bartelle1, Daniel H. Turnbull1 1Skirball Institute of Biomolecular Medicine, New York, New York, USA

MntR is an MRI reporter gene that localizes Mn within cells. In this work we show cellular T1w contrast in cells stably expressing MntR and our progress towards in vivo MntR expression.

Functional Connectivity & Brain Networks Room 718 B 11:00-13:00 Chairs: Vince D. Calhoun and Silvina G. Horovitz

11:00 24. Young Investigator Award Finalist: Differential Interictal Activity of the Precuneus/Posterior Cingulate Cortex Revealed by Resting State FMRI at 3T in Generalized Versus Partial Seizure Su Lui1, Luo Ouyang2, Qin Chen1, Xiaoqi Huang1, Hehan Tang1, Huafu Chen2, Dong Zhou1, Graham J Kemp3, Qiyong Gong1 1West China Hospital of Sichuan University, Chendu, People's Republic of China; 2University of Electronic Science and Technology of China, Chendu, People's Republic of China; 3University of Liverpool, Liverpool, UK

Resting state functional MRI was used to characterize the pattern of active brain regions in patients with epilepsy. 9 patients with partial seizure, 19 patients with generalized seizure SGC and 34 normal controls were recruited. 200 volumes of EPI images collected on a 3T were processed using the method of Fransson, which reveals information on regional low-frequency BOLD signal oscillations in the resting state without any a priori hypothesis. In GS, the lack of activation in precuneus/PCC may partly account for their more severe interictal deficits, compared to PS, in cognitive functions such as concentration and memory

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11:20 25. Disrupted Functional Connectivity Networks in Patients with Localization-Related Cryptogenic Epilepsy Jacobus F.A. Jansen1, Koen H.P. Stakenborg1, Marielle C.G. Vlooswijk1, H J.M. Majoie1, Paul A.M. Hofman1, Marc C.T.F.M. de Krom1, Albert P. Aldenkamp1, Walter H. Backes1 1Maastricht University Hospital, Maastricht, Netherlands

Decline of cognitive function is the most frequent co-morbid disorder in epilepsy. It is unclear what neuronal mechanisms underlie the cognitive and behavioral changes. Healthy controls and patients with chronic epilepsy underwent fMRI examination at 3.0 T, to assess possible changes in fMRI silent word generation activation patterns, lateralization indices and functional connectivities. No differences in word generation activation maps between healthy controls and patients with epilepsy were found, whereas functional connectivity analysis proved to be able to observe subtle differences in activation patterns. The functional connectivity properties seem to be indicative of the quality of performance, which is strengthened by the high correlation of functional connectivity values and cognitive scores.

11:32 26. A Longitudinal MR Functional Connectivity Study in Pediatric Subjects from 2wks to 2yrs Old Using Low-Frequency BOLD Synchronization Quan Zhu1, Chung-Yi Yang2, John H. Gilmore3, Weili Lin3 1Duke University, Durham, North Carolina, USA; 2National Taiwan University Hospital, Taiwan; 3University of North Carolina at Chapel Hill, Chapel Hill, USA

In this work, we report results on a longitudinal study where low-frequency BOLD synchronization was employed to explore the development of cortical connectivity in the Broca’s and Wernicke’s areas and Anterior Cingulate cortex (ACC) in pediatric subjects from 2wks to 2 yrs old, and demonstrate that it is feasible to investigate brain functional connectivity using BOLD synchronization in pediatric subjects without sedation, even in very young ages. Our results suggest that the application of this technique could potentially improve our understanding of brain functional development.

11:44 27. Age-Related Connectivity Changes in FMRI Data From Children Performing a Covert Verb Generation Task Prasanna Rasika Karunanayaka1, Scott Kerry Holland1, Vincent Jerome Schmithorst1, Elena Plante2 1Cincinnati Children's Hospital Research Foundation, Cincinnati, USA; 2University of Arizona, Tuscon, USA

Group ICA is a powerful data-driven technique capable of revealing the functional networks of the human brain based on fMRI data .To investigate the neuroanatomical bases of covert verb generation in 336 children, we used the fMRI paradigm of silent verb generation. Structural Equation Modeling (SEM) and group independent component analysis was combined to investigate the age-related connectivity changes among brain regions associated with covert verb generation. The results show the advantage of investigating covert verb generation in terms of cognitive modules and the associated developmental trends in connectivity.

11:56 28. Brain Connectivity During the Processing of Nouns and Verbs: A Dynamic Bayesian Network Analysis Deqiang Qiu1, Shing-Chung Ngan1, Li-Hai Tan1, Alice HD Chan1, Henry KF Mak1, Pek-Lan Khong1 1The University of Hong Kong, Hong Kong, People's Republic of China

Dynamic Bayesian network was used to study the connections among the brain regions activated during processing of nouns and verbs. Under simplifying assumptions, we arrived at a dynamic Bayesian network learning algorithm with reduced time complexity, which allowed us to test all possible connectivity models exhaustively and choose the best model based on the Bayesian information criterion (BIC) score. We found a posterior to anterior flow of processing of both nouns and verbs. The left medial frontal gyrus was found to play an important role in the network. For verb processing, strong involvements of motor cortex and cerebellum were found.

12:08 29. Connectivity of Complex Networks: A Monte Carlo-Based Approach for Dynamic Causal Modeling Dardo Tomasi1, Gene-Jack Wang1, Ruiliang Wang1, Nora D. Volkow2 1Brookhaven National Laboratory, Upton, USA; 2National Institutes of Health, Bethesda, USA

We here propose a data-driven dynamic causal modeling method that does not require a priori hypotheses to study the connectivity of complex brain networks. We show that stochastic methods commonly used in physics to solve complex many-body problems, and parallel computers can be used to find the optimal connectivity models of activated networks without a priori assumptions. Our approach demonstrate that the connectivity of the working memory is identical for the left and right brain hemispheres and the importance of the parietal-prefrontal loop in working memory.

12:20 30. The Functional Anatomy of SMA at Rest: Clustering and Connectivity Independently Measured with DTI and RS-FMRI Hubert M.J. Fonteijn1, 2, Evelinda Baerends2, 3, David Gordon Norris2 1Helmholtz Institute, Utrecht, Netherlands; 2F.C. Donders Institute for Cognitive Neuroimaging, Nijmegen, Netherlands; 3Leiden Institute for Brain and Cognition (LIBC), Leiden, Netherlands

There is an increasing interest in the analysis of resting-state fMRI data. It is however unclear at what level resting-state networks are organized. To address this issue, we have investigated resting state activation patterns from the SMA region, based on a parcellation scheme using anatomical connectivity from DTI. We have investigated whether the activation from the subregions are correlating exclusively with voxels within these subregions. We have also been able to establish similar clusters based on resting-state data alone, using discrete wavelets and fuzzy clustering and we have investigated resting state connectivity patterns with the rest of the brain.

12:32 31. Higher-Order Contrast Functions Improve Performance of Independent Component Analysis of Functional MRI Data with Low Signal-To-Noise Ratio Vincent Jerome Schmithorst1, Scott Kerry Holland1 1Children's Hospital Medical Center, Cincinnati, Ohio, USA

Independent Component Analysis (ICA) is increasingly being used as a data-driven methodology for the analysis of functional MRI (fMRI) data. The use of higher-order contrast functions (such as kurtosis or skewness), as opposed to lower-order functions (such as ln cosh) typically used for superGaussian sources, has been proposed due to the specific characteristics of fMRI signals. We present preliminary results from simulations and resting-state fMRI data comparing kurtosis to the ln cosh function in the presence of low SNR. Results suggest that optimal ICA performance in the presence of low SNR may also warrant the use of higher-order contrast functions.

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12:44 32. Partitioning Functional Connectivity Networks Using “community Structure” Algorithms Adam Schwarz1, Alessandro Gozzi1, Angelo Bifone1 1GlaxosmithKline Medicine Research Centre, Verona, Italy

We have investigated the structure of brain functional connectivity networks using an approach developed to detect communities in complex networks of social interactions. We apply this algorithm to pharmacological MRI data, and demonstrate anatomically meaningful and functionally compelling subdivisions that correspond to specific neurotransmitter systems targeted by the drug. The biological interpretation of these “communities” as a signature of functional segregation within the integrated network of brain activity is discussed, together with the relative merits of this approach with respect to existing methods to investigate the structure of functional connectivity networks.

HARDI/Q-Space Imaging Room 714 A/B 11:00-13:00 Chairs: Yaniv Assaf and Van Wedeen

11:00 33. Q-Space Diffusion Weighted MRI Analyzed with Maximizing Rician Likelihood Improves Reliability and Tissue Contrast Bennett Allan Landman1, Jonathan Andrew David Farrell1, 2, Seth A. Smith2, 3, Peter C. van Zijl, 23, Jerry L. Prince1 1Johns Hopkins University, Baltimore, Maryland, USA; 2Kennedy Krieger Institute, Baltimore, Maryland, USA; 3Johns Hopkins University School of Medicine, Baltimore, Maryland, USA

Q-space imaging is an emerging diffusion weighted MR imaging technique that shows great promise in classifying changes in tissue microstructure. Unlike diffusion tensor imaging, q-space imaging identifies the molecular diffusion probability density function without the need to assume a Gaussian distribution. Traditional analysis techniques use limited diffusion models (e.g., bi-exponential) to regularize noisy data and do not properly account for the properties of Rician noise. We present a robust M-estimator for diffusion probability density functions based on maximum likelihood. In simulation and in vivo spinal cord, the method improves reliability of the estimated probability functions and increases tissue contrast.

11:12 34. Computation of Diffusion Function Measures in Q-Space Using Magnetic Resonance Hybrid Diffusion Imaging Yu-Chien Wu1, 2, Aaron S. Field, 23, Andrew L. Alexander, 23 1University of Wisconsin-Madison, Madison , Wisconsin, USA; 2Madison, Wisconsin, USA; 3University of Wisconsin-Madison, Madison, Wisconsin, USA

The distribution of water diffusion in biological tissues may be estimated by a 3D Fourier Transform (FT) of diffusion-weighted measurements in q-space. In this study, methods for estimating diffusion spectrum measures (the zero-displacement probability, the mean-squared displacement, and the orientation distribution function) directly from the q-space signals are described. These methods were evaluated using both computer simulations and hybrid diffusion imaging (HYDI) measurements on a human brain. This new direct computation approach reduces HYDI data processing time and image artifacts arising from 3D FT and regridding interpolation. In addition, it is less sensitive to the noise and q-space truncation effects.

11:24 35. Simple Harmonic Oscillator Based Estimation and Reconstruction for One-Dimensional Q-Space MR Evren Ozarslan1, Cheng Guan Koay, Peter J. Basser 1National Institutes of Health, Bethesda, Maryland, USA

Dependence of the diffusion-weighted MR signal on the diffusion gradient strength was represented as a series of eigenfunctions of the simple harmonic oscillator Hamiltonian. This formulation made it possible to rapidly estimate the ensemble average propagator and potentially useful descriptors such as its moments and return-to-origin probability. The proposed technique has significant advantages over the previously employed biexponential curve fitting and cumulant expansion methods. Unlike these approaches, the simple harmonic oscillator based method is linear, and capable of approximating complicated signal profiles such as non-monotonic patterns due to diffraction-like effects.

11:36 36. Analysis of High B-Value Diffusion Images Using Fractional Order Calculus Xiaohong Joe Zhou1, 2, Osama Abdullah2, Dumitru Baleanu3, Richard L. Magin2 1University of Illinois Medical Center, Chicago, Illinois, USA; 2University of Illinois at Chicago, Chicago, Illinois, USA; 3Cankaya University, Ankara, Turkey

It is well known that diffusion-induced MR signal loss deviates from mono-exponential decay, especially at high b-values. We demonstrate that the anomalous diffusion behavior can be characterized by extending the Bloch-Torrey equation through application of the operators of fractional calculus. Theoretical analyses and experimental results have shown that a model for anomalous diffusion can be established by directly solving the fractionalized Bloch-Torrey equation in time and space. Using this mathematical tool, we may extend the applications of diffusion imaging beyond simply evaluating apparent diffusion coefficients and stretched exponential constant α, and eventually reveal new parameters related to tissue micro-environment.

11:48 37. Towards Better Understanding of Brain Tissue Using Directional Kurtoses by Orthogonal Transformation of Diffusion Kurtosis Tensor D (KDT) Edward Sai Kam Hui1, 2, Liqun Qi2, Matthew M. Cheung1, Kyle H. Cheng1, Joseph A. Helpern3, Jens H. Jensen3, Ed X. Wu1 1The University of Hong Kong, Pokfulam, Hong Kong; 2The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong; 3New York University School of Medicine, New York, USA

Orthogonal transformation of diffusion kurtosis tensor is implemented to obtain axial (K//) and radial kurtosis (K⊥) which measures kurtosis parallel and perpendicular, respectively, to principal diffusion direction, which could potentially yield extra information regarding diffusion environment in brain tissue. In vivo and ex vivo experiments were performed on normal adult SD rat brains. It was found that fixation has more effect on the intrinsic structure parallel than perpendicular to nerves as depicted by more increase in K// than increase in K⊥ suggesting that directional kurtoses has excellent sensitivity to changes in diffusion environments, and gains superiority to mean kurtosis (MK).

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12:00 38. In Vivo Higher-Order Contrast Measured with Generalized Diffusion Tensor Imaging Using Higher-Order Tensors Chunlei Liu1, Sarah Charlotte Mang2, Michael E. Moseley1 1Stanford University, Stanford, California , USA; 2University of Tuebingen, Tuebingen, Germany

The higher order tensor (HOT) model by Liu et al proposes to quantitatively characterize general diffusion processes using a series of diffusion tensors with increasing orders. Each order of these tensors offers a well defined physical interpretation, with the second order tensor meaning the second order cumulant (covariance matrix), the third order tensor meaning the third order cumulant (skewness tensor), and the fourth order tensor meaning the fourth order cumulant (kurtosis tensor). We present a very first in vivo implementation of generalized diffusion tensor imaging (GDTI) with HOT and propose a set of techniques to generate higher order diffusion contrast.

12:12 39. Effect of Diffusion Gradient Pulse Duration on Fibre Orientation Estimation Chun-Hung Yeh1, Jacques-Donald Tournier2, 3, Kuan-Hung Cho1, Ching-Po Lin1, Fernando Calamante2, 3, Alan Connelly2, 3 1Institute of Neuroscience, National Yang-Ming University, Taipei, Taiwan; 2Brain Research Institute, Melbourne, Australia; 3Department of Medicine, University of Melbourne, Melbourne, Australia

In the q-space formalism, the short gradient pulse approximation is preferable to determine spin displacement. However, we propose that the application of a longer £_ which is clinically achievable is theoretically beneficial for resolving fibre orientations, as it enhances both the DW signal and the contrast between the DW directions. We thus investigate the relationship between £_ and the DW signal measured as a function of orientation using both simulated and experimental data. The results show that prolonging £_ preferentially enhances the transverse DW signal. This effect is advantageous for estimating fiber orientations and hence for fiber-tracking applications.

12:24 40. A Recursive Algorithm to Decompose Orientation Distribution Function and Resolve Intra-Voxel Fiber Directions Fang-Cheng Yeh1, Van J. Wedeen2, Wen-Yih Isaac Tseng, 13 1National Taiwan University College of Medicine, Taipei, Taiwan; 2Harvard Medical School, Charlestown, Massachusetts, USA; 3National Taiwan University Hospital, Taipei, Taiwan

A recursive decomposition algorithm for resolving intra-voxel fiber directions in diffusion spectrum imaging (DSI) and q-ball imaging (QBI) is presented. The proposed algorithm recursively decomposes orientation distribution function (ODF) and obtains fiber directions.

12:36 41. Regularized Super-Resolution for Diffusion MRI Shahrum Nedjati-Gilani1, Geoff J M Parker2, Daniel C. Alexander1 1University College London, London, UK; 2University of Manchester, Manchester, UK

We present an algorithm that uses regularized super-resolution to find fibre populations and their respective orientations and volume fractions accurately from a sub-voxel scale in a 3D diffusion MRI acquisition. We can use our method to recover fibre configurations such as bending, fanning, and partial volume effects.

12:48 42. Spatial Normalization of the Fiber Orientation Distribution Based on High Angular Resolution Diffusion Imaging Data Xin Hong1, Lori Rose Arlinghaus1, Adam W. Anderson1 1Vanderbilt University, Nashville, Tennessee, USA

In this study an algorithm is developed to transform the Fiber Orientation Distribution (FOD) function based on HARDI data, which takes into account not only translation, but also rotation, scaling, and shearing effects of the spatial transformation. The algorithm is tested using both numerical phantom and in vivo human data. This technique makes it possible to compare the intra-voxel fiber distribution between subjects, which will be helpful in various clinical studies of white matter diseases.

CLINICAL CATEGORICAL COURSE Body MRI by the Experts III: Bowel/Peritoneum Room 716 A/B 11:00 - 13:00 Chair: Qun Chen, Clare Tempany, and Bernard E. Van Beers

Educational Objectives: Upon completion of this course, participants should be able to:

• Describe the impact of functional, quantitative, and molecular MR in abdominal imaging; • Apply new body MR techniques in their practice; • Use multiparametric MRI for improved diagnosis of abdominal diseases; • Describe indications of functional and quantitative MRI in the assessment of liver, pancreas, bowel, and kidney diseases; • Design new female pelvic and prostate protocols, introducing these methods and compare them to more conventional approaches; and • Appraise the indications for anatomical and functional imaging of the breasts and the lungs.

11:00 MR Enteroclysis and Colonography Thomas C. Lauenstein 11:30 MR of the Rectum Regina G. H. Beets-Tan 12:00 Anatomical and Functional MRI of the Pancreas

Maria A. Bali

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12:30 MR of the Peritoneum

Russell N. Low

CLINICAL CATEGORICAL COURSE Imaging Brain Tumors: From Physiology to Therapy Room 701 A 11:00 - 13:00 Chairs: Jeffry R. Alger and Alberto Bizzi

Educational Objectives: Upon completion of this session, participants should be able to:

• Describe clinical relevance of physiological MRI techniques in the dianosis of brain tumors; • Summarize recent findings related to the use of H-MRS, PWI, fMRI, and DTI for planning tumor resection and fractionated therapy; and • Discuss how physiological MRI techniques can be used to obtain a quantitative assessment of response to therapy.

11:00 Tumor Biology with MR Spectroscopic and Perfusion Imaging

Meng Law 11:25 Mapping the Language System for Extensive Resection of Low Grade Gliomas

Hugues Duffau 11:50 Diffusion Tensor Tractography around Brain Tumors: Concepts and Applications

Aaron S. Field 12:15 Imaging Response to Therapy with Magnetic Resonance

Thomas L. Chenevert

12:40 Discussion

Myocardial Perfusion & Viability Room 701 B 11:00-13:00 Chairs: Kerstin Bauner and Peter Kellman

11:00 43. Myocardial Perfusion MRI with Sliding Window and CG-HYPR Lan Ge1, Aya Kino1, Natasha Berg1, Xin Liu1, Nicole Mascheri1, Mark Griswold2, Andrew Larson1, Charles Mistretta3, James Carr1, Debiao Li1 1Northwestern University, Chicago, Illinois, USA; 2Case Western Reserve University, USA; 3University of Wisconsin-Madison, Madison, Wisconsin, USA

Image quality and slice coverage for myocardial perfusion MRI are limited by the temporal resolution of current approaches. This work demonstrated the feasibility of sliding CG-HYPR for accelerated myocardial perfusion imaging with a temporal resolution of one time frame per cardiac cycle. Using this method, the acquisition time per cardiac cycle was reduced dramatically, which allows increasing the number of slices for myocardial perfusion imaging and reducing motion artifacts. The signal changes of left ventricle and myocardium were verified by the comparison to conventional methods. Mean correlation coefficients between sliding CG-HYPR and reference images are 0.9672, 0.9423 for blood and myocardial signals, respectively.

11:12 44. K-T-Space Accelerated Myocardial Perfusion Bernd André Jung1, Matthias Honal1, Jürgen Hennig1, Michael Markl1 1University Hospital, Freiburg, Germany

Dynamic first-pass contrast-enhanced myocardial perfusion MRI is an important clinical tool that greatly benefits from acceleration in data acquisition in terms of spatial resolution or number of slices to acquire per heartbeat. Advanced dynamic parallel imaging techniques have been introduced such as k-t-SENSE and k-t-BLAST, k-t-GRAPPA, and PEAK-GRAPPA as an extension of k-t-GRAPPA to reduce total acquisition time or to increase spatiotemporal resolution. In a study with 11 patients an application of a k-t-space related GRAPPA technique to myocardial perfusion as non-periodic motion has been investigated.

11:24 45. Evaluation of Rigid and Non-Rigid Motion Compensation of Cardiac Perfusion MRI Hui Xue1, 2, Jens Guehring2, Jo V. Hajnal1, Daniel Rueckert, Sven Zuehlsdorff3, Kinda Saddi2, Christophe Chefdhotel2 1Hammersmith Hospital, Imperial College London, London, UK; 2Siemens Corporate Research, Princeton, New Jersey, USA; 3Siemens Medical Solutions USA, Inc., Chicago, USA

Myocardial Perfusion MRI can be undermined by subject motion, which makes sequences of images acquired during contrast uptake inconsistent. In this work, the performance of rigid and non-rigid motion compensation techniques is evaluated on a multi-center perfusion dataset containing more than 500 individual time series, obtained under clinically relevant conditions.The results confirm that motion correction is a frequent requirement (67% of cases in this sample). The registration based methods we developed were found to be effective in 98.5% of the cases tested.

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11:36 46. Investigating Myocardial Field Distortions During First Pass of a Gadolinium Based Contrast Agent in Perfusion Studies Pedro Ferreira1, Peter Gatehouse2, David Firmin1, 2, Chiara Bucciarelli-Ducci1, 2, Ricardo Wage2 1Imperial College, London, UK; 2Royal Brompton Hospital, UK

Myocardial perfusion studies are often affected by the dark rim artifact, which mimics an under-perfused region. One of the possible origins pointed out in literature for this artifact is field distortion. In this work field distortions were measured during first pass of Gd-DTPA in the heart for 10 patients and compared to both phantom work and numerical simulations, which were found to agree well with the in-vivo data. Field distortions happen mainly in the myocardium wall, especially for more horizontal hearts, but appear to be too weak to cause any loss of signal.

11:48 47. Evaluation of Microvascular Function of Residual Viable Myocardium in Infarct Zone After Percutaneous Coronary Intervention: Quantitative Myocardial Blood Flow Measurement Using Magnetic Resonance Mao-Yuan Su1, 2, Bai-Chien Lee3, Yen-Wen Wu3, Hsi-Yu Yu2, Woei-Chyn Chu4, Wen-Yih Isaac Tseng5, 6 1National Yang-Ming University, Taipei, Taiwan; 2National Taiwan University Hospital, taipei, Taiwan; 3National Taiwan University Hospital, Taipei, Taiwan; 4National Yang-Ming University, taipei, Taiwan; 5College of Medicine, National Taiwan University, Taipei, Taiwan; 6national Taiwan University Hospital, taipei, Taiwan

Left ventricular (LV) remodeling after acute myocardial infarction (AMI) is known to be associated with the size of the infarct myocardium. It has been reported that residual viable myocardium within the infarct zone plays a protective role against LV remodeling and is one of major determinants of regional functional recovery after AMI. In this study, we aimed to assess the microvascular function of the residual viable myocardium by using cardiovascular magnetic resonance (CMR) imaging to delineate the residual viable myocardium and quantify myocardial blood flow (MBF). Our results suggested that the microvascular function was generally impaired in the reperfused infarct zone, but more viability salvaged could preserve more microvascular function.

12:00 48. Balanced SSFP Myocardial BOLD Imaging: An Initial Evaluation in Patients with Known Coronary Artery Disease Rohan Dharmakumar1, Jordin D. Green2, Jacqueline Flewitt3, Matthias Voehringer3, Neil G. Filipchuk3, Debiao Li1, 4, Matthias G. Friedrich3 1Northwestern University, Chicago, Illinois, USA; 2Siemens Medical Solutions, Calgary, Canada; 3University of Calgary, Calgary, Canada; 4Evanston, Illinois, USA

Oxygen-sensitive myocardial imaging may be an alternative to first-pass perfusion methods. This workdemonstrates that SSFP-based BOLD MRI can detect regional myocardial perfusion deficits in patientswith coronary artery disease.

12:12 49. Pharmacokinetic Modelling of Delayed Gadolinium Enhancment in the Myocardium Benjamin Richard Knowles1, Phillip G. Batchelor2, Victoria Parish1, Mathew Ginks2, Stephen Sinclair1, Sven Plein3, Reza Razavi2, Tobias Schaeffter2 1King's College London, London, UK; 2King's College London, UK; 3University of Leeds, Leeds, UK

Standard myocardial perfusion imaging in the myocardium uses a two compartmental model to quantify the related pharmacokinetic parameters; however, an accurate quantification of pharmacokinetics in areas of late enhancing myocardium requires the addition of a third compartment. We report the first use of such a model to describe the uptake of contrast agent in myocardial infarctions. We fitted a three compartment model to data from images acquired 1-20 minutes post contrast agent administration. Initial results show that this model successfully describes late enhancement and could potentially to be a valuable tool for the quantification of myocardial late enhancement

12:24 50. MR Quantification of Regional Myocardial Oxygen Consumption Rate Kyle Stephan McCommis1, Haosen Zhang1, Robert J. Gropler1, Jie Zheng1 1Washington University School of Medicine, St. Louis, Missouri, USA

A cardiac MR method is demonstrated to quantify the regional myocardial oxygen consumption rate during hyperemia, by using the Fick’s principle. MRI data acquisition was performed in normal dogs, as well as dogs with a single vessel coronary stenosis. Each study session consisted of imaging at rest and pharmacologically-induced hyperemia. In normal dogs and normal myocardial regions of stenotic dogs, myocardial oxygen consumption rose similarly from the rest condition. However, the coronary artery stenosis attenuates the effect of hyperemia on the stenosis subtended region, which agrees well with other reports with human patients of coronary artery stenosis.

12:36 51. Quantified Delayed Enhancement in Myocardial Infarction Using Free Breathing Saturation Recovery SSFP Christian Stehning1, Victoria Parish2, Stephen Sinclair2, Eike Nagel2, Hannes Dahnke1, Tobias Schaeffter2 1Philips Research, Hamburg, Germany; 2King's College, London, UK

We present a T1 mapping method allowing the quantification of contrast agent concentrations in infarcted myocardium is presented. A submillimeter spatial resolution allows to differentiate different infarct territories. The acquisition is performed during free breathing.

12:48 52. MRI for the Detection of Catheter Ablation Scars of the Right Atrial Isthmus in Patients with Atrial Flutter David Maintz1, Murat Özgün1, Alexander Bunck1, Rene Botnar2, Walter Heindel1, Paulus Kirchhof1 1University of Münster, Münster, Germany; 2King's College, London, UK

In patients with atrial flutter, radiofrequency ablation of the isthmus between the inferior vena cava and the tricuspid valve is a common treatment procedure. In this study, we intended to investigate the feasibility to visualize ablation scars of the isthmus using MRI and to compare a standard breath-hold 2D scar imaging sequence with a high resolution free-breathing 3D scar sequence. 49 MR exams (28 before, 21 after RF ablation) were included. Sensitivity/specificity for the detection of ablation scars were 95%/79% (3D), 67%/89% (2D). We demonstrate that RF ablation scar can be visualized non-invasively with the use of T1w MRI. Visualization of scars of the isthmus in patients with atrial flutter may confirm procedural success of RF ablation and may correlate with clinical outcomes.

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MRI of Schizophrenia & Other Psychiatric Diseases Room 713 A/B 11:00-13:00 Chairs: Jonathan H. Gillard and John D. Port

11:00 53. A Novel Framework for Identifying DTI-Based Brain Patterns of Schizophrenia Peng Wang1, Ruben Gur1, Ragini Verma1 1Univ. of Pennsylvnia, Philadelphia, Pennsylvania, USA

Diffusion tensor imaging (DTI) provides rich information about brain tissue structure [1], especially white matter and has therefore gained attention in studying pathology of several diseases, such as schizophrenia, in a group-based analysis. In such research, it is important to accurately identify abnormal brain tissue that can classify patients and controls into two groups, for diagnosis, treatment and prognosis. However, conventional statistical methods are difficult to apply to DTI data due to its high dimensionality and nonlinearity. Most of the existing methods resort to a statistical t-test based on FA or kernel PCA features from tensors. However, the t-test usually assumes a single Gaussian distribution for each group, and a multivariate hypothesis testing is usually constrained by limited number of available samples and high-dimensional data. To address these issues, we present a novel group analysis framework in this paper. Rooted in the pattern classification theory, our method directly estimates the overlap between different groups using Bayes error rate. Unlike t-test, our method does not assume global Gaussian distribution for each group, but only considers data distribution to be locally smooth, thus facilitating separation of different groups when the data could have highly nonlinear structure, which is the case in DTI data. This framework also has the capability of combining multiple measurements that are extracted from tensor data, thus being able to handle multivariate testing. In this paper, the method is first used to identify abnormal brain regions that distinguish the patient group from control group, and is further validated by classifying patients from controls based on these regions. Experiments on 36 controls and 34 patients with schizophrenia show encouraging results.

11:12 54. Effects of Genetic Polymorphisms on White Matter Structure in Schizophrenia Measured with Diffusion Tensor Imaging Adam W. Anderson1, Mevhibe N. Tumuklu2, Lori R. Arlinghaus1, Tricia A. Thornton-Wells1, Xin Hong1, Herbert Y. Meltzer1 1Vanderbilt University, Nashville, Tennessee, USA; 2Gaziosmanpasa University Faculty of Medicine, Tokat, Turkey

Diffusion tensor imaging was used to measure the variations in white matter structure related to single nucleotide polymorphisms (SNPs) in the histamine H1 receptor gene. Statistical parametric maps reveal regions of white matter where anisotropy depends strongly on SNP genotype. Hence, DTI can be used to map the effects of genotype on brain structure, thereby providing an 'intermediate phenotype' that may help to improve understanding of the relationships between genes and behavior.

11:24 55. Tract-Specific Anisotropy Measures and Temporal Characteristics of Schizophrenia Abnormalities David Matthew Carpenter1, Cheuk Tang1, Joseph I. Friedman1, 2, Hof R. Patrick, Daniel G. Stewart1, Monte S. Buchsbaum1, Philip D. Harvey1, Jack M. Gorman3, Kenneth L. Davis 1Mount Sinai School of Medicine, New York, New York, USA; 2Pilgrim Psychiatric Center, West Brentwood, New York, USA; 3Mount Comprehensive NeuroScience, Inc., White Plains, New York, USA

Here we implemented a fiber tracking algorithm and used it to investigate the temporal nature of white matter abnormalities in schizophrenia. Quantitative DTI tractography was used to quantify the fractional anisotropy (FA) of the forceps minor and the pyramidal tracts bilaterally. The tractography approach showed a significant decline in FA that was correlated with the duration of illness in the forceps minor. This FA decline in patients is beyond that accounted for by normal aging.

11:36 56. Improved Discriminant Analysis in Schizophrenia Using Fractional Anisotropy and Apparent Diffusion Coefficient Images of Water Diffusion in Brain Babak A. Ardekani1, 2, Jay Nierenberg1, 2, Debra D’Angelo1, Matthew J. Hoptman1, 2 1Nathan Kline Institute, Orangeburg, USA; 2New York University School of Medicine, New York, USA

The main objective of this study was to determine if using FA and ADC images concurrently in linear discriminant analysis (LDA) results in increased classification accuracy as compared to using FA or ADC alone. We scanned 42 patients with schizophrenia and 42 normal controls subjects. A two-dimensional LDA was performed following feature extraction using singular value decomposition. Specificity, sensitivity, and overall accuracy were respectively 85.7%, 71.4%, and 78.6% for ADC images alone, 88.1%, 73.8%, and 81.0% for FA images alone, and 90%, 76.2%, and 83.3% when both ADC and FA were used for classification. The results suggest that using multiple brain imaging measures may improve discrimination accuracy.

11:48 57. The Association of Cerebral Deficits with the Symptoms in Drug-Naïve First Episode Schizophrenia: An Optimized VBM and Resting Functional Connectivity Study on 3T Su Lui1, Xiaoqi Huang1, Wei Deng1, Hehan Tang1, Lijun Jiang1, Dongming Li1, Tijiang Zhang1, Xiuli Li1, Tao Li1, Qiyong Gong1, 2 1West China Hospital of Sichuan University, Chendu, People's Republic of China; 2University of Liverpool, Liverpool, UK

Optimized voxel based morphometry (VBM) in conjunction with the analysis of the resting state functional brain connectivity was applied to determine the relationship of the cerebral deficits with the symptoms in drug-naïve first episode schizophrenia (FSE). 21 drug-naïve FSE and 21 age, sex, height, weight, handedness and years of education matched controls were recruited, and were scanned using a volumetric 3D SPGR sequence and an EPI sequence on a 3T MR imaging system. For first time, we characterized that the symptoms of FSE associated with both the regional structural deficits and the functional networks.

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12:00 58. Impaired Memory Consolidation in Schizophrenia and Its Relationship to Dentate Gyrus and Cornu Ammonis Activity: FMRI Evidence Vaibhav A. Diwadkar1, 2, Eric Murphy1, Simon B. Eickhoff3, Matcheri S. Keshavan1, 2 1Wayne State University SOM, Detroit, Michigan, USA; 2University of Pittsburgh SOM, Pittsburgh, Pennsylvania, USA; 3Forschungszentrum Juelich, Juelich, Germany

Schizophrenia is characterized in part by hippocampal related pathology. The hippocampus is the primary site in the brain for the initial consolidation of associative memories, and this process depends in part on NMDA receptor function. Schizophrenia is hypothesized to involve NMDA receptor hypofunction; therefore associative learning is an ideal paradigm using which to assess hippocampal function in the illness. We separately assessed changes in fMRI measured activity in the dentate gyrus and cornu ammonis sub-regions in the hippocampus during associative memory and demonstrate distinct patterns of pathological response in these sub-regions in schizophrenia.

12:12 59. Anterior Cingulate Glutamate is Greater During Low Relative to High Dose Methadone Maintenance Dose in Heroin-Dependent Volunteers Mark Greenwald1, Dalal Khatib1, Matcheri Keshavan1, Jeffrey Stanley1 1Wayne State University, Detroit, Michigan, USA

High-field short TE single-voxel 1H-MRS is used to determine in heroin-dependent subjects whether glutamate (GLU) levels in anterior cingulate cortex (ACC) and thalamus vary during within-subject manipulation of methadone maintenance dose. Subjects are first stabilized on high-dose methadone (scan 1), followed by reduction to a low dose (scan 2). All 6 completers in this ongoing study exhibit significantly lower GLU in ACC during high- vs. low-dose methadone. Heroin craving during high-dose methadone is positively correlated with change in ACC GLU during dose reduction. These findings are consistent with preclinical data and suggest new theoretical and therapeutic directions.

12:24 60. Basal Perfusion in Adolescents at Risk for Alcohol Use Disorders Ai-Ling Lin1, David C. Glahn2, Ahmad R. Hariri3, Douglas E E. Williamson2 1University of Texas Health Science Center , San Antonio, Texas, USA; 2University of Texas Health Science Center, San Antonio, Texas, USA; 3University of Pittsburgh, Pittsburgh, Pennsylvania, USA

The purpose of this study was to investigate alterations in baseline cerebral blood flow (CBF) in adolescents at risk for alcohol use disorder (AUD). The baseline CBF was measured in both low- and high-risk groups for AUD using pulsed ASL sequence. Compare to the low-risk group, the high-risk group shows higher CBF in bilateral amygala and ventromedial prefrontal cortex but less CBF in bilateral insula and occipital cortex. These preliminary findings suggest that adolescents at relatively high-risk for AUD exhibit altered patterns of resting CBF in distributed corticolimbic regions supporting emotional behaviors.

12:36 61. An Investigation of the Microstructure of Brain Tissue in Social Anxiety Disorder: A Turboprop-DTI Study Anton Orlichenko1, K Luan Phan2, Huiling Peng1, Emil F. Coccaro3, Konstantinos Arfanakis1 1Illinois Institute of Technology, Chicago, Illinois, USA; 2University of Michigan, Ann Arbor, Michigan, USA; 3University of Chicago, Chicago, Illinois, USA

Social anxiety disorder, also known as social phobia, refers to long-lasting anxiety, extreme distress and impaired ability to function, caused by perceived social threats. It has in the past been correlated with hyperactivation of the amygdala, and hypoactivation of ventral frontal areas believed to provide cognitive regulation of the limbic system. The aim of this study was to use Turboprop diffusion tensor imaging to examine differences in white matter microstructure between patients with social phobia and healthy controls.

12:48 62. Localization of White Matter Transverse Relaxation Time Abnormalities in Autism Yann Gagnon1, Tim Devito1, Janet Hendry1, N Gelman1, N Rajakumar2, P Williamson2, R Nicolson2, Dick Drost1 1University of Western Ontario, Lawson Health Research Institute, London, Canada; 2University of Western Ontario, London, Canada

The transverse relaxation time (T2) is a quantitative parameter of magnetic resonance imaging which is indicative of the molecular environment in brain tissue. In this study, T2 times of the basal ganglia were evaluated in a group of Tourette Syndrome (TS) patients. Images obtained at 3 Tesla using the GESFIDE technique were spatially normalized for statistical analysis. TS patients were found to have increased T2 of the caudate nucleus when compared with controls.

Thermal Therapy & Focused Ultrasound Room 715 A/B 11:00-13:00 Chairs: Nathan J. McDannold and Viola Rieke

11:00 63. MRI-Guided Midline Laser Glossectomy in Porcine Models: Evaluation of Safety and Efficacy for Reducing Tongue Base Volume Sherif G. Nour1, 2, Jamal J. Derakhshan, Simi Paul1, Jens O. Heidenreich1, Nathan Cross2, Fadi W. Abdul-Karim1, Jeong J. Park, Jeffrey L. Sunshine1, Jeffrey L. Duerk1 1University Hospitals Case Medical center / Case Western Reserve University, Cleveland, Ohio, USA; 2School of Medicine / Case Western Reserve University, Cleveland, Ohio, USA

Reducing tongue base volume has been shown to improve clinical outcomes in patients with obstructive sleep apnea (OSA). A technique for percutaneous laser ablation of the tongue base entirely guided and monitored under MRI is described and tested on porcine models. The ability to safely create large, therapeutic-type ablations within the tongue base utilizing this technique and the effect of this single-session treatment on tongue base shrinkage were specifically evaluated. Both safety and efficacy have been demonstrated. These results represent the first use of IMRI technology to achieve laser-induced glossectomy and constitute promising basis for future treatment of OSA patients.

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11:12 64. MR Targeting Guidance and MR Thermometry for Radiofrequency Ablation in Patients with Liver Tumours on an Interventional 1.5T Platform Alexandru Cernicanu1, Matthieu Lepetit-Coiffe1, Magalie Viallon1, Sylvain Terraz1, Christoph D. Becker1 1Geneva University Hospital, Geneva, Switzerland

With a closed-bore 1.5T MR system, clinical treatment of metastatic liver tumours (under 2.5 cm in diameter) using RF ablation technique was studied regarding targeting and real-time MR temperature monitoring; Based on a fully-balanced SSFP interleaved radial acquisition, targeting of the deep-situated tumour was achieved in about 22±10min; The RF device was made MR compatible in order to perform MR thermometry with a respiratory-triggered rapid gradient echo-echo planar imaging acquisition; MR temperature accuracy of 1.6±0.5 C was obtained in a non-heated region. Long axis diameter of RF lesion was 3.4±0.7cm overlapping the tumour in 14 of 15 nodules (confirmed both by 2-days-later-CT and 1-month-later-MR clinical images).

11:24 65. MR-Guided HIFU Thermotherapy with a Robotic Assistance System Axel Krafft1, Jürgen Jenne1, Jaane Rauschenberg1, Wolfhard Semmler1, R Jason Stafford2, Michael Bock1 1Deutsches Krebsforschungszentrum (dkfz), Heidelberg, Germany; 2The University of Texas, MD Anderson Cancer Center, Houston, USA

High intensity focused ultrasound (HIFU) is a non-invasive treatment modality which is often monitored by MR temperature measurements to assess and control thermal target tissue ablation. In this work a fixed-focus HIFU transducer was for the first time combined with a fully MR-compatible robotic assistance system originally designed for percutaneous MR-guided needle interventions. This combined system is tested for its suitability for MR-guided focus ultrasound applications in a phantom and an in vivo experiment. The combined system potentially offers greater flexibility than existing HIFU setups and can achieve a high geometric precision in very short positioning times.

11:36 66. Volumetric HIFU Ablation Under 3D Guidance of Rapid MRI Thermometry Max Köhler1, Charles Mougenot2, 3, Bruno Quesson3, Julia Enholm1, Brigitte Lebail4, Christophe Laurent5, Chrit Moonen3, Gösta Ehnholm1 1Philips Medical Systems, Vantaa, Finland; 2Philips Medical Systems, France; 3Laboratory for Molecular and Functional Imaging, Bordeaux, France; 4Pellegrin Hospital, Bordeaux, France; 5Saint André Hospital, Bordeaux, France

A volumetric sonication method in conjunction with a simultaneous rapid volumetric thermal monitoring is introduced as a safe, fast and accurate alternative to current point-by-point sonication methods. This study on in-vivo pig thighs demonstrates an improved ablation efficiency and homogeneity with increased sonication volumes. Apparent lesion volume dimensions as seen from the thermal dose maps were in good agreement with corresponding non-perfused contrast enhanced dimensions.

11:48 67. 3.0-T MRI-Guided Focused Ultrasound Ablation Versus MRI-Guided Needle-Wire Placement for the Pre-Operative Localization of Non-Palpable Breast Tumors: An Experimental Study Annemarie Caroline Schmitz1, 2, Maurice A. A. J. van den Bosch2, Viola Rieke2, Fred M. Dirbas2, Kim Butts Pauly2, Willem P.T.M. Mali1, Bruce L. Daniel2 1University Medical Center Utrecht, Utrecht, Netherlands; 2Stanford University Medical Center, Stanford, USA

The purpose of this experimental study is to compare the accuracy of MRI-guided focused ultrasound ablation(MRI-gFUS) versus MRI-guided needle-wire placement(MRI-gNW) for the localization of non-palpable breast tumors. Sixteen turkey breasts were used. An artificial tumor was created. MRI-gFUS localization(n=8) was performed with the ExAlblate 2000 system(Insightec). No case of positive margins was found in the FUS-group(0%) and 2 cases in the NW-group(25%)(P=0.5). The mean minimum tumor-free margin±SD in the FUS-group was significantly larger(4.7±2.9mm), than the NW-group(0.9±1.4mm)(P=0.004).The results of this experimental study indicate that MRIg-FUS is as accurate as MRIg-NW for pre-operative localization of non-palpable breast tumor.

12:00 68. Endoluminal Ultrasound Applicator with an Integrated RF Coil for High-Resolution MRI-Guided HICU Thermotherapy Mihaela Rata1, 2, Rares Salomir1, Reiner Umathum3, Jurgen Jenne3, François Cotton, 24, Cyril Lafon1, Michael Bock3 1INSERM, U 556, Lyon, France; 2UCBL 1, Lyon, France; 3DKFZ, Heidelberg, Germany; 4CHU Lyon Sud, Lyon, France

High intensity contact ultrasound (HICU) under MRI guidance may provide minimally invasive treatment of endocavitary digestive tumors in the esophagus, colon or rectum. In this study, miniature receive-only coils were integrated into an endoscopic ultrasound applicator to offer high resolution MRI guidance of thermotherapy. The integrated coils provided significantly higher sensitivity than a 4-element extracorporeal phased array coil and the standard deviation of the MR thermometry (SDT) improved by to a factor of 7 at 10 mm depth in tissue. Half millimeter resolution became feasible for fast MR thermometry while providing an excellent SDT (0.3 C). The endoscopic device was actively operated under automatic temperature control, demonstrating very accurate performance.

12:12 69. In Vivo MRI-Monitoring of Gadodiamide Release from Phosphatidylglyceroglycerol Containing Thermosensitive Liposomes in Heated and Non-Heated Tumors Michael Peller1, Alenka Schwerdt2, Martin Hossann3, Herbert M. Reinl4, Tungte Wang3, 5, Lars H. Lindner3, 6, Maximilian Reiser 1University Hospital of Munich, Munich, Germany; 2Ludwig-Maximilians University, Munich, Germany; 3University Hospital of Munich, Germany; 4Department of Clinical Radiology, Germany; 5GSF-National Research Center for Environment, Neuherberg, Germany; 6 GSF-National Research Center for Environment, Neuherberg, Germany

Purpose of this study was to investigate the dynamics of mild temperature induced contrast agent release from phosphatidylglyceroglycerol containing thermosensitive liposomes with encapsulated Gd-DTPA-BMA (Gd-TSL) in the presence of tumor perfusion, using a clinical experimental setting. Tumor bearing mice were investigated at 1.5T after intravenous injection. The temperature induced release of contrast agent at 42 C causes a fast and strong increase of T1-weigthed signal. Intraindividual comparison of heated and non-heated tumors showed a significant higher contrast agent release in heated tumors. This demonstrates the potential of Gd-TSL for monitoring moderate regional hyperthermia in tumor treatment concepts in a clinical MRI-setting.

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12:24 70. In Vivo Visualization of an Optical Reporter Gene Expression Transported by a Cellular Vector and Locally Activated by MRI Guided HIFU in Rat Kidney Omer Eker1, Bruno Quesson1, Nora Frulio1, Colette Deminiere2, Chrit Moonen1, Franck Couillaud1, Nicolas Grenier1 1Laboratory IMF, Bordeaux, France; 2CHU Pellegrin, Bordeaux, France

Gene therapy using a cellular vector requires efficient targeting and control of the activation of the transgene of interest. Genetically modified C6 cells expressing Luciferase under a heat sensitive promoter have been injected in the renal artery and their intrarenal distribution visualized by Bioluminescence imaging. Two days after injection, kidneys were focally heated non invasively with HIFU under MRI thermometry automatic control, with different heating conditions. Presence of these cells in the kidney were successfully detected by Bioluminescence imaging and the zones emitting light corresponded to the heated region, indicative of successful in vivo targeting and control of transgene activation.

12:36 71. MRI-Guided Focused Ultrasound-Enhanced Chemotherapy of 9L Rat Gliosarcoma: Survival Study Lisa Hsu Treat1, 2, Yongzhi Zhang1, Nathan McDannold1, Kullervo Hynynen1, 3 1Harvard Medical School and Brigham and Women's Hospital, Boston, Massachusetts, USA; 2Harvard-MIT Health Sciences and Technology, Cambridge, Massachusetts, USA; 3Sunnybrook Health Sciences Centre, Toronto, Canada

We investigated the impact of MRI-guided focused ultrasound-enhanced delivery of doxorubicin to brain on survival in rats with 9L gliosarcoma. In this study, we have shown that targeted drug delivery by MRI-guided focused ultrasound significantly improves survival time in rats with aggressive glioma, compared to chemotherapy alone (0.02< p<0.05). Such demonstrated efficacy in an in vivo tumor model represents a large step forward in the development of this technique toward treating patients with disorders of the central nervous system.

12:48 72. MRI Monitoring of Ultrasound-Targeted Microbubbles Destruction April M. Chow1, 2, Chi-tat Chiu1, Ke Xia Cai1, Ed X. Wu1 1The University of Hong Kong, Pokfulam, Hong Kong

Ultrasound-targeted Microbubble Destruction (UTMD) has been used to deliver genes or drugs to specific tissues utilizing microbubbles cavitation and sonoporation effect through guidance of ultrasound imaging. However, ultrasound imaging cannot visualize soft tissues adequately and non-site-specific therapeutic effect may result from the imaging ultrasound irradiation. MRI would be the most effective imaging modality to guide UTMD for genes or drugs delivery due to its better soft tissue delineation without interaction with microbubbles. In this study, we demonstrate that MRI can detect microbubble cavitation and MRI monitoring of UTMD is feasible.

Electromagnetic Safety Room 717 A/B 11:00-13:00 Chairs: Christopher M. Collins and Stuart Crozier

11:00 73. SAR Implications of Different RF Shimming Techniques in the Body at 7 Tesla Bob van den Bergen1, Cornelis A. T. van den Berg1, Peter Luijten1, Jan J. W. Lagendijk1 1University Medical Center Utrecht, Utrecht, Netherlands

The development of ultra high field MRI systems has introduced serious challenges for body imaging with respect to SAR and B1+ field non-uniformity,

which results in signal voids in the region of interest. RF shimming can remove these signal voids by optimizing the phases and amplitudes of the individual RF excitation elements. We present an overview of the implications of three different RF shimming techniques both for the average and for the local maximum SAR. All three can improve the B1

+ field and reduce the average SAR, but only one method results in a reduction of local SAR peaks.

11:12 74. Comprehensive RF Safety Concept for Parallel Transmission Systems Ingmar Graesslin1, Dennis Glaesel1, Sven Biederer2, Peter Vernickel1, Ulrich Katscher1, Ferdinand Schweser1, Bjoern Annighoefer1, Henk Dingemans3, Giel Mens3, Gert v. Yperen3, Paul Harvey3 1Philips Research Europe, Hamburg, Germany; 2Lübeck University, Lübeck, Germany; 3Philips Medical Systems, Best, Netherlands

RF safety is a prerequisite for in vivo parallel transmission MRI experiments. In this abstract, a comprehensive RF patient safety concept is proposed to ensure scanning within the SAR limits. The concept builds on two different measures. Before the scan, SAR calculations are carried out in (almost) real-time for the desired multi-transmit RF demand waveform, to verify its conformity with existing SAR limits according to IEC. During the scan, the deviation from the desired waveform is monitored to detect unintended violations of the SAR limits or any unsafe conditions.

11:24 75. Poseable Male and Female Numerical Body Models for Field Calculations in MRI Zhangwei Wang1, Christopher W. Penney2, Raymond J. Luebbers2, Christopher M. Collins1 1The Pennsylvania State University, Hershey, Pennsylvania, USA; 2Remcom, inc., State College, Pennsylvania, USA

Different body positions can dramatically affect the SAR distribution, but due to limitations in available numerical body model positions some researchers have resorted to removing portions of the arms to eliminate contacts between the hands and the torso. In this paper, we apply our recently-developed methods for making models poseable to investigate effects of arm position on the SAR distribution for thoracic imaging at 64MHz (1.5T) in a whole-body high-pass birdcage coil.

11:36 76. Numerical Field Evaluation of Healthcare Workers When Bending Towards High-Field MRI Magnets Hua Wang1, Adnan Trakic1, Feng Liu1, Stuart Crozier1 1The University of Queensland, Brisbane, Australia

In MRI, healthcare workers may be exposed to strong static and dynamic magnetic fields outside of the imager. Presented are numerical evaluations of electric fields/currents in anatomically-equivalent male and female human models (healthcare workers) as they lean towards the bores of three superconducting magnet models (1.5T, 4T and 7T) and x, y and z- gradient coils. The combined effect of the 1.5T superconducting magnet and the three gradient coils on the body models is compared with the contributions of the magnet and gradient coils separately. The simulation results indicate that it is possible to induce field quantities above regulatory guidelines, especially when the MRI operator is bending close towards the main magnet and all three gradient coils are switched simultaneously.

Monday AM

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11:48 77. Detailed Experimental and Computational Analyses of the RF Field at 7T: Effects of the Load Content on Achieving 90o Tip Without SAR/Power Violations YiK-Kiong Hue1, Tamer S. Ibrahim1 1University of Pittsburgh, Pittsburgh, Pennsylvania, USA

In ultra high field human experiment, different subject/loading have significant influence on the performance of the coils. Computational and experimental analyses at 7T are presented to examine the effect of loading on achieving a 90 degree tip angle without local/global SAR violations. The relationship between the flip angles and the local/global SAR value is also studied.

12:00 78. Dyadic Green’s Functions for Electrodynamic Calculations of Ideal Current Patterns for Optimal SNR and SAR Riccardo Lattanzi1, 2, Daniel K. Sodickson3 1Harvard-MIT, Boston, Massachusetts, USA; 2Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA; 3New York University Medical Center, New York, New York, USA

In this work we present a semi-analytical method to calculate SNR and SAR based on a mode expansion using dyadic Green’s functions in a dielectric sphere. Ultimate intrinsic SNR and SAR can be computed by employing a complete set of surface current modes, and the corresponding ideal surface current patterns can be derived. This formalism holds also in the case of actual coils and can be useful to investigate the physical behaviors of the RF fields during MR reception and MR excitation. Ideal current patterns can be used as a reference to improve coil design.

12:12 79. Specific Absorption Rate Mapping Using MR Thermometry in a Transmit-Receive Head Coil at 3.0T Sukhoon Oh1, Christopher M. Collins1 1The Pennsylvania State University, Hershey, USA

In this study, experimentally-acquired temperature maps are used to calculate the SAR distribution from a head-sized transmit-receive birdcage coil in an agar-gel phantom at 3.0T. A single quadrature birdcage coil was used for both heating and imaging purposes, in contrast to studies in diathermy and ablation using separate coils at different frequencies. Results agree well with expectations from electromagnetic theory. Future experiments will focus on high-power RF heating in phantoms with transmit arrays for the purposes of validating predictions from sophisticated numerical calculations.

12:24 80. Direct SAR Measurements Using MRI: A Phantom Study of Proton Decoupling at 7 Tesla Andrew Webb1, Thomas Neuberger 1Penn State University, University Park, Pennsylvania, USA

SAR at high field is conventionally estimated using either electromagnetic simulations or fibre optic measurements at a very few physical locations. However, by measuring the slope of temperature rise vs. time, the SAR can actually be measured directly using MRI. One of the areas where SAR limitations are most relevant is the use of proton decoupling in heteronuclear spectroscopy experiments. This study measures local SAR using MRI in phantoms with different conductivities using a range of proton decoupling powers.

12:36 81. Measurement of Electric Fields Induced in a Human Subjects Due to Alternating Magnetic Gradient Fields and Natural Body Movements in Static Magnetic Fields Paul Glover1, Richard Bowtell1 1University of Nottingham, Nottingham, UK

A method for measurement of electric fields induced in conductive samples by temporally changing magnetic fields is described. The method was first verified experimentally. In vivo human measurements of electric fields were made with suitable custom built dipole probes. Measurements of electric fields were then made using natural movements in the vicinity of a 3T magnet as well as due to gradient switching. Induced electric fields at the surface of the torso were found to be typically 0.15 (m) times the applied dB/dt.

12:48 82. Human Nerve Stimulation Threshold Determination in a Planar Gradient System Rebecca Emily Feldman1, Christopher Judson Hardy2, Bulent Aksel2, John Fredric Schenck2, Blaine Alexander Chronik1 1University of Western Ontario, London, Canada; 2GE Global Research, Niskayuna, New York, USA

Gradient induced peripheral nerve stimulation in humans limits MRI operation. The Z-axis of a novel planar gradient system was tested to determine the nerve stimulation thresholds. Rise times between 200 and 1400 μ s were tested. The resulting threshold curve was higher than any previously reported gradient system stimulation thresholds. The planar gradients may be operated at both gradient strengths and slew rates more than twice that of conventional cylindrical gradient designs.

Monday PM

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GOLD CORPORATE MEMBER LUNCHTIME SYMPOSIUM Siemens Medical Solutions Hall F 13:00 - 14:00

SPECIAL SYMPOSIUM Grant Writing: Prospects, Pearls, and Pitfalls Room 801 A/B 14:00 - 16:00 Chairs: Richard L. Ehman and Mark A. van Buchem

Educational Objectives: Upon completion of this session, participants should be able to:

• Identify the most important grant funding opportunities that are available for MR researchers in the US and Europe; • Describe key elements and strategies for preparing successful research proposals; • Describe how to move forward after an unsuccessful application; and • Explain the perspective of grant reviewers.

14:00 Opening Comments

14:05 Grant Prospects for MRI Research: National Institutes of Health Belinda Seto 14:30 Grant Prospects for MRI Research: European Union Koos Geleijns

14:45 Critical Elements of a Successful Grant Proposal

Charles A. Mistretta

15:15 Strategies for Moving Forward after an Unsuccessful Grant Application Richard L. Ehman

15:30 Panel Discussion

ISMRM/SMRT JOINT FORUM Nephrogenic Systemic Fibrosis – A Multidisciplinary & Global Issue Room 701 A 14:00 - 16:00 Chairs: David W. Stanley

Educational Objectives: Upon completion of this session, participants should be able to:

• Relate the history and impact of NSF on the MR community; • Describe the global approach and findings for NSF; • Recognize and validate the need for careful patient screening for all MRA procedures; and • Implement improved patient handling and screening procedures for gadolinium contrast studies.

14:00 NSF: Where have we been, where are we going?

Emanuel Kanal 14:25 NSF: Challenges of Gadolinium and NSF outside of North America Tim Leiner 14:45 Gadolinium and NSF: Risk factor screening and contrast administration Eric E. Williamson 15:05 NSF Management: A Technologist Perspective Cindy R. Comeau 15:30 Panel Discussion

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Quantitative Approach to Diffuse Liver Disease Room 716 A/B 14:00-16:00 Chairs: Donald G. Mitchell and Valérie Vilgrain

14:00 83. Diagnosis of Liver Fibrosis by Multifrequency Viscoelastic Parameter Evaluation in Magnetic Resonance Elastography Dieter Klatt1, Patrick Asbach1, Uwe Hamhaber1, Sebastian Papazoglou1, Bernd Hamm1, Jürgen Braun1, Ingolf Sack1 1Charité, Berlin, Germany

Multifrequency magnetic resonance elastography was used for separating healthy volunteers from patients with histologically proven liver fibrosis based on hepatic viscoelastic parameters. Measurements were performed on 18 healthy volunteers and 10 patients using a single-shot spin-echo planar imaging sequence. The viscoelastic parameters were determined according to the springpot model which accounts for both elastic and viscous properties of a tissue. The AUROC-value of 92.2% for differentiation between healthy volunteers and patients demonstrates the potential of multifrequency magnetic resonance elastography as a clinical method for diagnosing liver fibrosis.

14:12 84. Value of Shear Wave Attenuation as a Tissue Characterization Parameter in MR Elastography of the Liver Meng Yin1, Sudhakar K. Venkatesh2, Yogesh K. Mariappan1, Kevin J. Glaser1, Roger C. Grimm1, Armando Manduca1, Anthony J. Romano3, Richard L. Ehman1 1Mayo Clinic, Rochester, Minnesota, USA; 2National University of Singapore, Singapore; 3Naval Research Laboratory, Washington, District Of Columbia, USA

Magnetic Resonance Elastography (MRE), a non-invasive technique for quantitatively assessing the mechanical properties of soft tissues, has been shown to have high sensitivity and specificity for diagnosing hepatic fibrosis by detecting elevated shear stiffness. Shear wave attenuation, which causes decrease in amplitude with distance, is another potential parameter for tissue characterization that can be obtained with MRE. We implemented a method for estimating shear wave attenuation from wave images and to evaluate this parameter as marker for fibrosis in a series of 63 examinations. The promising results provide continued motivation for further developing shear attenuation inversion algorithm for hepatic MRE.

14:24 85. MR Elastography of Non-Alcoholic Steatohepatitis in the Rat Najat Salameh1, Benoit Larrat2, Jorge Abarca-Quinones1, Isabelle Leclercq1, Ralph Sinkus2, Bernard E. Van Beers1 1Université Catholique de Louvain, Brussels, Belgium; 2Laboratoire Ondes et Acoustique, Paris, France

The aim of our study was to assess the role of MR elastography in staging NASH and to evaluate which parameters influence the visco-elastic measurements in this model of chronic liver disease.

14:36 86. Evaluation of Hepatic Fibrosis with Portal Fraction and Portal Pressure Gradient Using MRI Yuenan Wang1, Hyeonjin Kim, R Todd Constable 1Yale University, New Haven, Connecticut, USA

Assessment of hepatic fibrosis is vital to clinical outcomes but non-invasive methods are lack. A previous MRI perfusion study showed portal fraction (PF) was highly correlated with portal pressure (PP) so that PF might be a surrogate of the invasive PP measurement. A recently proposed portal pressure gradient (PPG) method also demonstrated its potential in evaluating the disease. This work aims to compare the performance of these two methods in 31 rats with various degrees of hepatic fibrosis. Both methods were highly correlated with fibrosis scores. PPG demonstrated higher accuracy and sensitivity and did not require contrast agent.

14:48 87. New Proposal for the Staging of Nonalcoholic Steatohepatitis: Evaluation of Liver Fibrosis on Gd-EOB-DTPA-Enhanced MRI Natsuko Tsuda1, Masahiro Okada2, Takamichi Murakami2 1Bayer Yakuhin, Ltd., Osaka, Japan; 2Kinki University School of Medicine, Osakasayama, Japan

We investigated whether Gd-EOB-DTPA-enhanced MRI is useful for NASH staging based on the severity of liver fibrosis. Choline-deficient diet-induced NASH rats were subjected to Gd-EOB-DTPA-enhanced MRI. Signal intensities in the liver were measured, and the relative enhancement (RE) was calculated. The time of maximum RE (Tmax) and elimination half-life of RE (T1/2) were compared. The rate of liver fibrosis was measured, and the correlation between the fibrosis rate and Tmax or T1/2 was evaluated. It was found that there was a significant correlation between the fibrosis rate and Tmax or T1/2 (r = 0.90 or 0.97, p < 0.01).

15:00 88. A Liver Function Test Based on Measurement of Liver-Specific Contrast Agent Uptake Olof Dahlqvist Leinhard1, 2, Nils Dahlström, 23, Per Sandström4, Torkel Brismar5, Johan Kihlberg, 24, Örjan Smedby, 23, Peter Lundberg1, 2 1Linköpings University, Linköping, Sweden; 2Center for Medical Image Science and Visualization (CMIV), Linköping, Sweden; 3Linköping University, Linköping, Sweden; 4Linköping University Hospital, Linköping, Sweden; 5Karolinska University Hospital, Huddinge, Sweden

Using a simplified model for liver-specific contrast agent dynamics, quantitative analysis of liver-specific contrast agent concentration in the liver and spleen in ten healthy volunteers, seven receiving Gd-EOB-DTPA and three Gd-BOPTA, was performed. An uptake rate was estimated for the hepatobiliary compartment, compensating for differences in renal extraction rate, blood volume and administered dose. In good agreement with known pharmacokinetics, the uptake rate value after 20 minutes was more than 10 times higher for Gd-EOB-DTPA than for Gd-BOPTA, and decreased uptake was noted in four patients with elevated bilirubin levels.

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15:12 89. Gradient Echo FMRI Study of Oxygenation Changes in the Livers of Chronic Ethanol-Treated Rats Manfred Brauer1, Lesley M. Foley2 1University of Guelph, Guelph, Canada; 2Carnegie Mellon University, Pittsburgh, Pennsylvania, USA

Chronic ethanol treatment causes hypoxic liver damage by increasing hepatic oxygen demand and decreasing oxygen supply. Functional MRI can measure tissue oxygenation changes in situ. We used gradient echo fMRI to study liver oxygenation changes in living chronic ethanol-treated rats and controls to show that alcohol greatly decreases and slows the response to hyperoxia, hypoxia and carbogen challenge vs. controls. Liver signal intensities doubled with carbogen inhalation in controls, with no change in alcoholic rats. TE-dependence studies confirm that both SE and GE fMRI studies are consistent with BOLD contrast. Low-volume hemoximetry showed that alcoholic rats had decreased blood oxygen levels in the hepatic artery and portal and hepatic veins under all challenge conditions. Morphometric analysis showed that alcoholic livers’ vasculature was compressed and less responsive to systemic challenge, confirming the fMRI results. This shows that fMRI can noninvasive monitor organ oxygenation status, and that carbogen challenge combined with gradient echo fMRI can readily distinguish healthy from alcoholic liver.

15:24 90. Evaluation of Hepatic Iron Concentrations by R2* Magnetic Resonance Imaging in 35 Patients with Iron Overload: Comparison of R2* Measurements at 1.5T and 3T and Validation with Liver Biopsies Claudia M. Hillenbrand1, Ralf B. Loeffler1, M. Beth McCarville1, Ruitian Song1, Eileen Hansbury1, Martha Rieman1, Nicole Mortier1, Matthew P. Smeltzer1, Chin-Shang Li1, Fred Hoffer1, Larry Kun1, Russell Ware1, Jane Hankins1 1St. Jude Children’s Research Hospital, Memphis, Tennessee, USA

The aim of this work was to conduct a comprehensive evaluation of liver iron concentration (LIC) obtained by R2*-MRI at 1.5T and 3T in patients with iron overload, and to correlate these R2* values directly with LIC measurements derived from liver biopsies. Further objectives were to study the reliability of R2* LIC measurements as a function of magnetic field strength B0 and to establish a relationship between LIC data measured by R2*-MRI at 3T and 1.5T.

15:36 91. Diagnosis of Hepatic Siderosis with a Novel Breath-Hold Multi-Echo T2* Sequence in Patients with Chronic Liver Disease Hersh Chandarana1, Ruth Lim1, Mariela Losada1, Vivian Lee1, Elizabeth Hecht1, Danny Kim1, Bachir Taouli1 1NYU Medical Center, New York, New York, USA

We assessed the performance of a novel multi-echo breath hold T2* sequence for detection of iron in the liver parenchyma, using histopathology as the reference, and we demonstrated significant differences in liver T2* and liver/muscle T2* ratio in patients with iron deposition compared to patients without hemosiderosis. Breath hold T2* sequence had excellent sensitivity, specificity, and accuracy for detection of liver siderosis, when compared to in- and out of phase imaging.

15:48 92. Comparison Between 1.5T and 3T Single Voxel 31P MRS of Human Liver in Health and Disease Marzena Wylezinska1, 2, Jeremy Cobbold2, Julie Fitzpatrick2, Philip S. Murphy3, Joe Hajnal2, Isobel Jane Cox2, Simon Taylor-Robinson2 1Hammersmith Hospital, Imperial College London, London, UK; 2Hammersmith Hospital, Imperial College London, London, UK; 3Pfizer, Sandwich, UK

We report the results of a comparison between localized 31P MRS of human liver performed at 1.5T and 3T in the same subjects using the same methodology. Comparisons were performed in terms of spectral resolution, signal to noise (S/N) of PME and PME/PDE ratios.1H decoupling in 31P MR spectra improved resolution at both field strengths (particularly PME and PDE). Further improvement in resolution was evident at 3T. There was an improvement in S/N (~21%). There was a good correlation between the two field strengths, but a small difference in PME/PDE ratios between 1.5T and 3T using the paired test.

Imaging Functional Networks in the Brain Room 701 A 14:00-16:00 Chairs: Brad Buchbinder and Kirk Welker

14:00 93. MIDAZOLAM SEDATION DISRUPTSTS the CORTICOLIMBIC NETWORK CONNECTION: An FcMRI Study Naranjargal Dashdorj1, Alexakis Charilaos1, Jaroslav Hlinka1, Rob Mason1, Quazi Siddiqui1, Dorothee Auer1 1University of Nottingham, Nottingham, UK

Functional neuroimaging modalities are increasingly applied to study functional connectivity (fc) defined as synchronisation of spatially remote neurophysiological events. Spontaneous low frequency fluctuations of the BOLD fMRI signal have been successfully used to study fc in the brain ‘at rest'. Advanced processing for spurious correlations allowed in recent years to characterise disease-specific alterations including the dysregulation of cortical-limbic circuitry in major depression. Moreover, cortico-limbic dysregulation as assessed by fc BOLD fMRI were found to be reversible after chronic antidepressant treatment.However, it remains unclear if and how acute pharmacological manipulations affect the functional connectivity between cortical-limbic networks. To our best knowledge, this is the first study investigating the effects of anxiolytic and sedative drug midazolam on fc in the cortico-limbic circuit in healthy volunteers.

14:12 94. An FMRI Study of Age Effects on Frontal-Striatal Neural Circuit Functions David C. Zhu1, Rose T. Zacks1, Jill M. Slade1 1Michigan State University, East Lansing, Michigan, USA

The frontal-striatal neural circuit is thought to be associated with attention and executive function. To understand the modification of this neural circuit with aging, a rapid-event related fMRI flanker paradigm was applied to study the difference between the young (age 20 ± 3 yrs) and older (age 74 ± 6 yrs) populations. This study found that various anatomical regions associated this circuit were modified with aging as reflected by either the amplitude or latency of the BOLD response.

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14:24 95. Reliable Modeling of Resting-State Emotional Networks in Major Depressive Disorder: Applicability of Exploratory Structural Equation Modeling to Small Sample Sizes George Andrew James1, Scott J. Peltier2, Richard Cameron Craddock3, Stephen M. LaConte4, Helen S. Mayberg3, Xiaoping P. Hu1 1Emory University and Georgia Tech, Atlanta, USA; 2University of Michigan, Ann Arbor, USA; 3Emory University, Atlanta, USA; 4Baylor College of Medicine, Houston, USA

Exploratory SEM evaluated the neural network mediating emotion for fMRI resting-state data with healthy (n=28) and depressed (n=5) samples. Jackknife and split-sample reliability testing assessed SEM validity. The winning model for controls consistently beat its closest rivals despite exclusion of 1-5 subjects. This model showed moderately negative influence of thalamus upon cingulate and reciprocal feedback loops within cingulate and within prefrontal cortices. Randomly splitting the sample into halves or quarters and repeating the analysis yielded qualitatively similar models. Yet depressed and control samples differed dramatically, thus demonstrating the feasibility of exploratory SEM for detecting functional differences despite small samples.

14:36 96. Better Recovery Following Stroke is Associated with Normalization of Resting-State Connectivity Ali-Mohammad Golestani1, Andrew Demchuk1, Bradley G. Goodyear1 1University of Calgary, Calgary, Canada

fMRI has not emerged as a tool to assess acute stroke, due to difficulties associated with patients performing tasks. We propose the strength of resting-state connections (connectivity) as an index of function that does not require tasks. Twelve stroke patients with a sensory-motor deficit underwent two MRI sessions (<24 hours and 90 days post-stroke). Eight fully recovered by day 90. Twelve healthy volunteers are also recruited. Connectivity in all patients at day0 was less than healthy controls. Recovered patients regained connectivity by day 90, whereas non-recovered patients did not. Connectivity may potentially link stroke injury with brain function and communication.

14:48 97. A 3 T Functional MRI Study of the Resting State Networks in Aging Paola Valsasina1, Maria A. Rocca1, Martina Absinta1, Antonia Ceccarelli1, Andrea Falini1, Giuseppe Scotti1, Giancarlo Comi1, Massimo Filippi1 1Scientific Institute and University Ospedale San Raffaele, Milan, Italy

Aim of this study was to investigate the influence of normal aging on resting state networks (RSN) using independent component analysis in a group of 49 healthy subjects, with age ranging from 20 to 69 years. Ten relevant RSN were detected: two visual RSN; two sensorimotor RSN; five fronto-parietal-temporal RSN -three bilateral and two lateralized to left and right, respectively, and one parietal RSN, that included the precuneus and the posterior cingulum. Correlations with age were found only for one visual and one sensorimotor RSN, suggesting that the different RSN of the healthy brain might respond differently to aging.

15:00 98. Altered Memory Network Organisation in Left Temporal Lobe Epilepsy Associated with White Matter Structural Changes Natalie Laura Voets1, Steve M. Smith2, Jane E. Adcock, Richard Stacey3, Yvonne Hart, Katherine Carpenter, Paul M. Matthews1, Christian F. Beckmann 1GSK, London, UK; 2Oxford University, FMRIB Centre, Oxford, UK; 3John Radcliffe Hospital, Oxford, UK

Memory reorganisation in temporal lobe epilepsy remains central to predicting surgical outcome. Recurrent seizures may arise as a result of aberrant connectivity within the mesial temporal lobes, resulting in altered structural coherence between regions of the memory network rather than hemispheric reorganisation per se. This study used TICA and voxel-wise diffusion analyses to identify altered structural coherence within the memory network in left temporal lobe epilepsy patients relative to healthy volunteers. These functional changes were related to white matter integrity along the contralesional uncinate fasciculus.

15:12 99. The Effect of Menstrual Cycle on Women’s Visceral Pain Perception Jianli Wang1, Helena F. Wrzos, Christopher M. Collins1, Jelena Zinnanti, Wanzhan Liu, Qing Li, Paul J. Eslinger, Qing X. Yang1, Michael B. Smith1, Ann Ouyang 1Penn State College of Medicine, Hershey, Pennsylvania, USA

The effect of menstrual cycle on the brain response to the visceral pain stimulation was studied on eleven healthy women using fMRI. Although there was no significant subjective perception difference of the same level of visceral stimulation between the two menstrual phases, during the luteal phase there was a significant increase of brain activation responding to the visceral pain stimulation than during the follicular phase. This finding supports the notion that the visceral pain perception may be augmented during the luteal phase at the central nervous system level.

15:24 100. Increased Desire for Food When Fasted is Associated with Increased FMRI Activation of the Ventral Striatum, Insula and Amygdala Anthony Peter Goldstone1, Christina Prechtl de Hernandez1, Kinan Muhammed1, Gabriel Bell1, Giuliana Durighel1, Emer Hughes1, Adam D. Waldman, 12, Jimmy D. Bell1 1Hammersmith Hospital, Imperial College, London, UK; 2Charing Cross Hospital, Imperial College Healthcare NHS Trust, London, UK

We examined how regional brain activity measured by fMRI varies with nutritional state (fasted vs. fed) when viewing food pictures. 18 non-obese healthy volunteers (age 19-36y) were scanned on 2 separate mornings after an overnight fast or 1hr after breakfast. There was significant activation of the ventral striatum, insula and amygdala when viewing high-calorie vs. object or high- vs. low-calorie pictures when fasted, but not when fed, which mirrored how appealing the pictures were rated. Increased hunger and desire for food when fasted vs. fed is associated with increased activation in brain regions involved in reward, cue-elicited craving and emotion.

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15:36 101. Reduced Fronto-Hippocampal Connectivity in Schizophrenia During Associative Learning: Relevance for NMDA-Mediated Synaptic Dysplasticity Eric Murphy1, Matcheri S. Keshavan1, 2, Vaibhav A. Diwadkar1, 2 1Wayne State University SOM, Detroit, Michigan, USA; 2University of Pittsburgh SOM, Pittsburgh, Pennsylvania, USA

The hippocampus and prefrontal cortex are critical regions in the encoding-retrieval memory circuit. Both regions are impaired in schizophrenia, yet few studies have assessed their functional connectivity in the illness specifically during tasks of memory encoding. In our fMRI study, patients and controls participated in an associative memory task during which they iteratively learned the associations between objects and locations in space. Functional connectivity was assessed with seed voxels drawn in each subject from the cornu ammonis region in the right hippocampus. Contrast analyses showed reduced fronto-hippocampal connectivity in patients relative to controls during memory encoding.

15:48 102. Brain Functional Correlates of Accuracy and Reaction Time During Performance of the Digit Symbol Substitution Test in the Elderly Vijay K Venkatraman1, Howard J. Aizenstein, Jack Guralnik, Jeff D. Williamson, Marco Pahor, Lenore Launer, Anne B. Newman, Stephanie Studenski, Nancy Glynn, Caterina Rosano 1University of Pittsburgh, Pittsburgh, Pennsylvania, USA

Several previous functional MRI studies in the elderly have identified age-related increased prefrontal activation in association with working memory performance. The primary hypotheses accounting for the increased activation include compensation or dedifferentiation. This current study tests these competing models using the digit symbol substitution task, a task involving working memory and processing speed, which is particularly sensitive to cognitive changes associated with aging. The findings suggest that older adults engage distinct overlapping networks of fronto-parietal regions to perform the DSST with greater accuracy and shorter reaction times.

Time-Resolved (4D) Contrast-Enhanced MRA Room 701 B 14:00-16:00 Chairs: Frank R. Korosec and Kambiz Nael

14:00 103. 3D Phase Contrast MRA of the Thoracic Aorta at 3T: Feasibility and Effect of Standard and Blood-Pool Contrast Agents Jelena Bock1, Alex Frydrychowicz1, Thorsten A. Bley1, Aurelien F. Stalder1, Max F. Russe1, Manuela Keckeis1, Juergen Hennig1, Michael Markl1 1University Hospital Freiburg, Freiburg, Germany

Flow sensitive 4D MRI permits the measurements of three directional blood flow velocities. These data can be used to derive additional information on vascular geometry by phase contrast (PC) angiography. Detailed evaluation of PC angiography image quality in the thoracic aorta compared to the reference standard CE-MRA was performed in a study in 3 groups (without contrast agent, with extravascular and with blood pool contrast agent) on a collective of 31 volunteers. Quantitative and qualitative evaluation of image quality demonstrated that PC-MRA can provide reliable angiography of the thoracic aorta of good quality compared to CE-MRA.

14:12 104. Clinical Applications of Contrast Inflow Dynamics MRA (CIDA): Novel Approach for ECG-Gated Dynamic Contrast Enhanced MRA Maggie M. Fung1, Ehud J. Schmidt2, Maureen N. Hood3, Godtfred Holmvang4, Raymond Y. Kwong5, Vincent B. Ho3 1GE Healthcare, Bethesda, Maryland, USA; 2GE Healthcare, Boston, Massachusetts, USA; 3National Naval Medical Center, Bethesda, Maryland, USA; 4Massachusetts General Hospital, Boston, Massachusetts, USA; 5Brigham and Women’s Hospital, Boston, Massachusetts, USA

A novel multiple-temporal-phase ECG-gated 3D contrast enhanced MRA approach with automatic triggering is presented. The efficient use of cardiac cycle for imaging, and a variable-center slice ordering scheme, enable the acquisition of high resolution, motion suppressed, temporally-selective contrast-enhanced images in a parallel manner, thus allowing completion within a single breathhold. This increases the robustness of ceMRA and streamlines workflow in the clinical setting. The flexible temporal selectivity enables visualization of arterial and venous phase with short temporal separation. This technique can also be used to evaluate morphological changes of the vasculatures in different cardiac phases.

14:24 105. Highly Accelerated (>10x) Parallel Acquisition for 3D Time-Resolved CE-MRA of the Calves Clifton R. Haider1, Nobert G. Campeau1, James F. Glockner1, John Huston1, Stephen J. Riederer1 1Mayo Clinic, Rochester, Minnesota, USA

The purpose of this work is to describe how 2D SENSE with 2D homodyne processing can be applied to peripheral MRA to provide an order of magnitude (>10X) reduction of acquisition time. It is hypothesized that a 2D SENSE-accelerated CArtesian Projection Reconstruction-Like acquisition can provide a time series of diagnostic quality, 1 mm3 isotropic spatial resolution images of the lower legs with 5 sec update times and 20 sec image acquisition times. Results demonstrate high temporal fidelity, high spatial resolution, and the robust nature of the highly accelerated CE-MRA sequence which can readily distinguish arterial from and venous phase.

14:36 106. Quantification of the in Vivo Kinematics of the Superficial Femoral Artery Due to Hip and Knee Flexion Using Magnetic Resonance Imaging Gilwoo Choi1, Nathan M. Wilson1, Christopher P. Cheng1, Robert J. Herfkens1, Charles Anthony Taylor1 1Stanford University, Stanford, California , USA

The interaction between the musculoskeletal system and the vasculature in the lower extremities plays a major role in determining superficial femoral artery (SFA) deformation. We used magnetic resonance imaging to investigate whether the location of the SFA with respect to the femur contributes to the observed shortening of the SFA with hip and knee flexion. Volume coregistration between two different image acquisitions was performed using the femur geometry as a reference. We found that the proximal part of the SFA moved more inferiorly than the distal segment, which contributed to shortening of the SFA.

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14:48 107. Comparison of 3D-TRICKS and 3D Bolus Chase MR Angiography for Evaluation of Infra-Popliteal Arteries Xiaoming Zhang1, Honglei Zhang2, Hsien Wang3, Yi Wang2, Martin R. Prince2 1Shandong University Qilu Hospital, Jinan, People's Republic of China; 2Weill Medical College of Cornell University, New York, New York, USA; 3Columbia College, New York, New York, USA

To compare the utility of 3D time resolved MRA and 3D bolus chase MRA for evaluating infra-popliteal arteries, data from 113 patients were reviewed retrospectively. The image quality was determined. Among all of the factors(age, gender, weight, ulcer/gangrene/cellulitis, diabetes, hypertension, CHF and arterial phase duration), only U/G/C and arterial phase duration had statistically significant partial effects indicating TRICKS provides more information in calves with fast flow due to ulceration, gangrene or cellulitis. In patients with slower flow and longer arterial phase with late venous enhancement, TRICKS is unnecessary and may be eliminated to reduce the total Gd dose.

15:00 108. Comparison of HYPR Stack-Of-Stars and HYPR VIPR to TRICKS in Peripheral CE MRA Yan Wu1, Kevin Johnson1, Oliver Wieben1, Julia velikina1, Andres Carrillo2, Steven Kecskemeti1, Charles A. Mistretta1, Frank R. Korosec1 1University of Wisconsin-Madison, Madison, Wisconsin, USA; 2GE Healthcare, Evanston, Illinois, USA

HYPR is a reconstruction algorithm that enables rapid frame update rates while providing high SNR and temporal accuracy. In this study, three time-resolved imaging methods were compared, the stack-of-stars acquisition with HYPR reconstruction, the VIPR acquisition with HYPR reconstruction, and 3D Cartesian TRICKs method. The three methods were used to acquire contrast-enhanced MR angiograms of the peripheral vessels in healthy human volunteers. It has been demonstrated that both HYPR methods provide better spatial and temporal resolution than TRICKs; in comparing the HYPR methods, VIPR permits higher undersampling factors (better spatial or temporal resolution), whereas HYPR stack-of-stars is more geometrically suited.

15:12 109. Optimizing Peripheral Contrast-Enhanced MRA Using A-Priori Knowledge of Bolus Kinetics Through the Optimal Choice of Imaging Parameters and Acquisition Time< Jeffrey Harold Maki1, 2, Silke Potthast2, David J. Glickerman1, Cecil E. Hayes2, Maisie E. Wang2, Gregory J. Wilson3 1Puget Sound VAHCS, Seattle, Washington, USA; 2University of Washington, Seattle, Washington, USA; 3Philips Medical, Cleveland, Ohio, USA

Through the a-priori knowledge of individual patient bolus kinetics, optimal timing for single-injection moving table peripheral CE-MRA can be determined to avoid venous enhancement. Knowing this, system specific parameter choices (2D SENSE factor, bandwidth, flip angle, TR and TE) can be uniquely determined to maximize SNR for any given patient at the desired acquisition time. We describe the theory behind these choices, show how to construct protocols to achieve maximal SNR with minimal venous enhancement, and demonstrate clinical examples (MRA vs DSA).

15:24 110. Clinical Experience of HYPR FLOW YiJing Wu1, Kevin M. Johnson1, Julia Velikina1, Patrick Turski2, Charles A. Mistretta2 1University of Wisconsin, Madison, Wisconsin, USA; 2University of Wisconsin Medical School, Madison, Wisconsin, USA

Phase Contrast (PC) HYPR FLOW employs PC VIPR images as the composite and reconstructs the first pass Time Resolved Contrast Enhanced (TR-CE) VIPR acquisition using HYPR LR technique. HYPR FLOW decouples the temporal resolution, which is defined by TR-CE VIPR acquisition, from the spatial resolution and SNR, which depend on the PC VIPR acquisition, resulting in both high temporal resolution and isotropic spatial resolution with preserved SNR from the PC images. In addition, the phase contrast scan will add flow information to the CE-MRA time frames and provide velocity information suitable for the calculation of hemodynamic parameters such as pressure map and wall shear stress (WSS) which are potentially beneficial for understanding of the physiologic conditions behind diseases such as arterio-venous malformation (AVM). This abstract presents our clinical experience with HYPR FLOW including the contrast waveform fidelity, spatial resolution, SNR improvement over the VIPR method, and the physiological information beyond the contrast enhanced angiography.

15:36 111. 7-Tesla Time-Resolved Contrast-Enhanced 3D MRA (TWIST) of the Intracranial Vessels Stefan Maderwald1, 2, Jens M. Theysohn1, 2, Oliver Kraff1, 2, Susanne C. Ladd1, 2, Karsten Wicklow3, Peter Schmitt3, Mark E. Ladd1, 2, Harald H. Quick1, 2 1Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen, Germany; 2Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen, Germany; 3Siemens Medical Solutions, Erlangen, Germany

Three dimensional contrast-enhanced magnetic resonance angiography (CE-MRA) is a well established, reliable, and accurate technique for the evaluation of vascular pathologies of the intracranial vessels at 1.5T. When performing time-resolved 3D MRA of the intracranial vessels, the signal-to-noise ratio (SNR) achievable at 1.5T can be a limiting factor in simultaneously supporting the desired spatial and temporal resolution. In this study we evaluated the potential of 7-Tesla MRA for time-resolved high-resolution 3D CE-MRA of the intracranial vessels using the TWIST (Time-resolved angiography WIth Stochastic Trajectories) technique.

15:48 112. Influence of the Injection Rate on Vessel Signal and Image Quality in First Pass Imaging with Gadofosveset (Vasovist®) Henrik Jakob Michaely1, Ulrike I. Attenberger2, Christian Fink1, Maximilian F. Reiser2, Stefan O. Schoenberg1 1University Hosptial Mannheim, Mannheim, Germany; 2University of Munich, Munich, Germany

This study investigates the influence of the injection rate of gadofosvest on the image quality and the vessel enhancement during the steady state. In 21 healthy volunteers three different injection rates (1ml/s, 2ml/s, 4ml/s) were applied. No significant differences could be found in peak signal intensity in the thoracic and abdominal aorta as well as in the kidneys. With a slow injection rate of 1ml/s a significantly longer purely arterial imaging window was achieved.

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MRS of Animal Brain Room 713 A/B 14:00-16:00 Chairs: Jun Shen and Ivan Tkac

14:00 113. In Vivo High Resolution Magnetic Resonance Spectroscopy of the Adult Zebrafish Brain at 9.4T Samira Kabli1, Herman P. Spaink1, Huub J. M de Groot1, A Alia1 1Leiden University, Leiden, Netherlands

Zebrafish is increasingly used as model organism for understanding brain diseases especially due to similar organization of brain components as that of human. In this study we optimized ο MRI and localized 1H MRS sequences at 9.4T to get metabolic profile of the zebrafish brain in vivo. A high resolution spectrum was obtained from a voxel as small as 3.3 οl placed in the middle of the zebrafish brain which gave excellent separation of resonances from various brain metabolites. Our study suggests that zebrafish brain has similar metabolite profile as that of human brain which proves zebrafish as a good model organism for human brain disorders

14:12 114. Neurochemical Profile of Hippocampal-Specific Iron Transporter Slc11a2 (DMT-1) Knock-Out Mice Ivan Tkac1, Erik S. Carlson1, Anna Petryk1, Michael K. Georgieff1 1University of Minnesota, Minneapolis, Minnesota, USA

In vivo 1H NMR spectroscopy at 9.4 T was used to investigate neurochemical changes in hippocampus of CamKII α -cre/S1c11a2 flox/flox double-mutant mice with knock-out of the iron transporter Slc11a2 in forebrain neurons. Iron content was selectively reduced in hippocampus by 40% in knock-out (KO) relative to wild type (WT) mice. Behavioral tests showed cognitive deficit of KO mice relative to WT. Of all 17 metabolites quantified in hippocampus only Lac levels were significantly reduced in KO mice relative to WT controls, which may indicate reduced energy production.

14:24 115. Metabolic Changes in Rat Frontal Cortex After Injection of Pentylenetetrazole Measured by Proton MR Spectroscopy at 9.4T Shaolin Yang1, D. Bruce Vaupel1, Hanbing Lu1, Thomas J. Ross1, William Rea1, Steven M. Demny1, Elliot A. Stein1, Yihong Yang1 1National Institute on Drug Abuse, NIH, Baltimore, Maryland, USA

Seizures were induced in rats by intraperitoneal injection of pentylenetetrazole (PTZ, 70 mg/kg). The time series of metabolite concentrations in the frontal cortex of adult rat brain were measured in vivo before and after the injection by localized 1H MRS spectroscopy at 9.4T (3 time points before the injection and 4 time points after, 25 minutes for each time point). Compared to the baseline levels, the average concentrations of glutamine (Gln) and ã-aminobutyric acid (GABA) (n = 7) significantly increased post injection but reached peaks at different time.

14:36 116. Cerebral Activation by Fasting Results in Lactate Accumulation in the Hypothalamus Ines R. Violante1, Jelena Anastasovska2, Gina J. Sanchez-Canon2, Tiago B. Rodrigues1, Laura Nieto1, Stephen R. Bloom3, James R. Parkinson3, Jimmy Bell2, Sebastian Cerdan1 1CSIC, Madrid, Spain; 2Hammersmith Hospital, London, UK; 3Imperial College, London, UK

We investigate the neuroglial metabolic interactions underlying appetite control during the feeding/fasting cycles. We administered an i.p. injection of (1-13C) glucose (20 µmol/g) to C57BL/6 mice, fixed the brain with high power microwaves (5kW), dissect the hypothalamus from the remaining cerebral structures and analyzed the 13C distribution in these regions by 13C HRMAS. Our results indicate that cerebral activation by fasting results in increased (3-13C) lactate and decreased (4-13C) glutamate levels in the hypothalamus. This finding suggests that the activation by fasting occurs most probably through the Astrocyte to Neuron Lactate Redox Shuttle, as in other sensorial activation processes.

14:48 117. Preliminary Studies of MDMA Induced Brain Hyperthermia Using Spectroscopic Imaging and 1H-[13C]MRS Lihong Jiang1, Robin A. de Graaf, Kevin L. Behar 1Yale University, New Haven, Connecticut, USA

In this study, we combined brain temperature mapping using the temperature-dependent frequency shift of water relative to NAA with 1H-[13C] MRS measurements of 13C turnover following acute MDMA-induced hyperthermia. The SI temperature map showed regional differences in temperature elevation, lower values in cortex and higher values in hippocampus. Glutamate and glutamine 13C turnover from [1,6-13C] glucose appeared faster during MDMA hyperthermia suggest increased oxidative metabolism.

15:00 118. Overcoming Experimental Challenges in the Assessment of Metabolic Fluxes with [1,6-13C-2]glucose in Mouse Brain Christine Nabuurs1, Dennis Klomp1, Andor Veltien1, Bart Van de Bank1, Arend Heerschap1 1Radboud University Nijmegen Medical Center, Nijmegen, Netherlands

One of the largest hurdles in the assessment of metabolic conversion by MRS with 13C labeled glucose infusion in mouse brain, is the determination of time resolved 13C enrichment of labeled metabolites in vivo during the MR experiment. These preliminary results demonstrate a coil setup and method, that allows for detection of glutamate and glutamine signals using POCE and DEPT methods sequentially to obtain spectra in the same VOI in a mouse brain. This enables both good separate detection of labeled metabolites and evaluation of isotopic enrichment.

15:12 119. NMR Investigations of Acetate Transport and Metabolism in the Rat Brain In Vivo Anant Bahadur Patel1, 2, Robin A. de Graaf1, Douglas L. Rothman1, Robert G. Shulman1, Kevin L. Behar1, Graeme F. Mason1 1Yale University School of Medicine, New Haven, USA; 2Centre for Cellular and Molecular Biology, Hyderabad, India

In the present study we investigated transport and metabolism of acetate in rat brain in vivo. Cerebral metabolite levels and 13C labeling were measured in vivo at 7 Tesla using 1H-[13C]-NMR spectroscopy in halothane-anesthetized rats receiving intravenous infusions of [2-13C]acetate. Steady-state brain acetate increased linearly with plasma level, whereas Gln-C4 labeling, which reflects the oxidation of acetate by the astroglial TCA cycle, reached saturation for plasma levels ¡Ý15 mM. The maximum rate of acetate utilization was ~14% of total (neuronal + glial) oxidative metabolism.

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15:24 120. Cerebral Phosphate Metabolite Profiles and Their Differentiation in Human, Cat and Rat Brains: A Comparison Study of In Vivo 31P MRS at High Fields Xiao-Hong Zhu1, Fei Du1, Yi Zhang1, Wei Chen1 1Center for Magnetic Resonance Research, Minneapolis, Minnesota, USA

In vivo 31P MRS provides useful measures of a large number of cerebral phosphate metabolites and tissue pH. It is particularly important for studying the ATP metabolism and bioenergetics in the brain noninvasively. The reliability of 31P MRS measurement can be significantly improved at high field. We have conducted a study to determine the brain phosphate metabolite profiles in human and two animal species of cat and rat at high fields (7-9.4T). Significant differences were found in the measured metabolite concentrations and tissue pH among the human and animal brains. Our results provide the standard phosphate metabolite profiles of the healthy human, cat and rat brains. This information should be valuable for cerebral metabolic study in these species, especially when comparing physiology versus pathology states in a specific brain of interest.

15:36 121. In Vivo High Resolution Localized Two Dimensional Magnetic Resonance Spectroscopy in Mouse Brain Niels Braakman1, Thomas Oerther2, Huub de Groot1, A Alia1 1Leiden University, Leiden, Netherlands; 2Bruker BioSpin GmbH, Rheinstetten, Germany

Localized two-dimensional magnetic resonance spectroscopy (2D MRS) is revolutionizing the in vivo studies of brain metabolites due to improved spectral resolution and unambiguous assignment opportunities. Despite the fact that there are large numbers of transgenic mouse models available for neurological disorders, localized 2D MRS has not yet been implemented in the mouse brain due to size constraints. In this study we optimized a localized 2D proton chemical shift correlated spectroscopic sequence at 9.4T to obtain highly resolved 2D spectra from localized regions in the mouse brain in vivo. To our knowledge this is the first in vivo application of 2D MRS in mouse brain. The L-COSY method yields consistent, reproducible results, and thus allows the clear and unambiguous identification of multiple brain metabolites from a single measurement. Such information will prove invaluable in future studies of brain disorders in mouse models.

15:48 122. Examining Neuro-Metabolic Correlations Between Resting Rat Brain Activity and Cerebral Metabolite Contents/Metabolic Rates: A 1H/31P MRS Comparison Study Fei Du1, Yi Zhang1, Xiao-Hong Zhu1, Wei Chen1 1University of Minnesota, Minneapolis, Minnesota, USA

Increases in neuronal activity are accompanied by elevated cerebral metabolic rates of glucose and oxygen consumption (CMRglc, CMRO2) at the activated sites. The end result of glucose and oxygen consumptions is the production of ATP molecules in mitochondria through ATPase. ATP is the fundamental cellular energy currency, and its hydrolysis to inorganic phosphate (Pi) and ADP is coupled to all energy requiring process in the cells. It is, thus, interesting to understand the neuro-metabolic coupling in the brain. In this comparative study, we investigated the correlations between the varied EEG activity through changing the anesthesia depth and the cerebral metabolite concentrations and metabolic rates which can be measured by in vivo 31P and/or 1H MRS. We found that the ATP and glucose metabolic rates are more closely coupled with the varied EEG activity in the resting rat brain as compared to steady-state metabolite concentrations. Thus, the imaging of these rates should provide sensitive and quantitative measures of brain bioenergetics associated with neuronal activity. Finally, this comparison study also supports a tight neuro-metabolic coupling in the rat brain.

Cartilage Imaging: Clinical & Translational Research Applications Room 717 A/B 14:00-16:00 Chairs: Christine Chung and Christian Glaser

14:00 123. Longitudinal Evaluation of Cartilage Degeneration in ACL-Injured Knees Using MR T1rho Quantification – a Preliminary Study Xiaojuan Li1, Jonathan Cheng1, Radu I. Bolbos1, C Benjamin Ma1, Thomas M. Link1, Sharmila Majumdar1 1University of California, San Francisco, San Francisco, California , USA

Patients with anterior cruciate ligament (ACL) injuries tend to develop osteoarthritis despite ACL reconstruction. The goal of this study was to longitudinally evaluate cartilage degeneration in ACL-injured knees using MR T1rho relaxation time quantification. Six patients with acute ACL injuries were scanned at 3T at baseline (prior to surgery), two-week, six-month and one-year after ACL reconstruction. Significantly elevated T1rho were observed in bone-marrow-edema-like-lesion (BMEL)-overlying cartilage at both baseline and one-year follow-up, despite significant decrease of BMEL volume at one-year (P < 0.05). This preliminary data suggested that there is potential early degeneration in cartilage of ACL-injured knees.

14:12 124. The Value of Pre-Contrast T1 Measurement for DGEMRIC Wei Li1, Rachel Scheidegger1, Ying Wu1, Robert R. Edelman1, Pottumarthi V. Prasad V. Prasad1 1Evanston Hospital and Northwestern University Feinberg School of Medicine, Evanston, Illinois, USA

This study was to evaluate if δ R1, which needs the use of combination of pre- and post-contrast acquisition, can provide better differentiation of osteoarthritis (OA) with healthy subjects for dGEMRIC. Pre- and post-contrast T1 measurements were performed in 17 OA patients and 14 healthy subjects with 2D IR-FSE or/and 3D LL techniques. High correlation was observed between T1Gd and δ R1. δ R1 does slightly improve the differentiation of OA from healthy subjects. This modest improvement needs to be weighed against the additional cost and effort in acquiring T1pre.

14:24 125. Reproducibility of DGEMRIC in the Human Knee Joint at 1.5 T Juhani Multanen1, Erkki Rauvala2, Eveliina Lammentausta2, Risto Ojala2, Ilkka Kiviranta3, Arja Häkkinen1, Ari Heinonen1, Miika T. Nieminen2, 4 1University of Jyväskylä, Jyväskylä, Finland; 2Oulu University Hospital, Oulu, Finland; 3Helsinki University Hospital, Helsinki, Finland; 4University of Oulu, Oulu, Finland

Long-term reproducibility of the dGEMRIC technique was studied in single slice measurements of the central lateral femoral condyle and underlying tibial cartilage in the sagittal plane, and in central patellar cartilage in the axial plane. dGEMRIC measurements in ten asymptomatic volunteers were repeated three times with average interval of 5 days. The absolute reproducibility, as measured by RMS coefficient of variation was 4.2%, 5.5% and 4.8% for bulk cartilage in the slice for femur, tibia and patella, respectively. The reproducibility at various topographical locations for superficial and deep cartilage ROIs ranged between 4.7-12.9% while the intraclass correlation coefficient was 0.45-0.98.

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14:36 126. Single Section Versus Volumetric Analysis of DGEMRIC Scans in a Longitudinal Multicenter MultivendorTrial : The A9001140 Study Nitya Krishnan1, Bradley Wyman2, Robert Buck3, Marie-Pierre Hellio3, Saara Totterman4, Jose Tamez4, Deborah Burstein1 1Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA; 2Pfizer Global Research and Development, Groton, Connecticut, USA; 3Pfizer Global Research and Development, Ann Arbor, Michigan, USA; 4VirtualScopics, Rochester, New York, USA

This study analyzes a subset (control n=31, OA n=22) of the A9001140 longitudinal multicenter, multivendor trial at 3T. Good correlations were found between results utilizing analysis of a single section from each condyle versus analysis of the entire cartilage region. Similar to single site, 1.5T trials, cartilage from KLG0 knees had higher dGEMRIC indices than KLG3. A slight increase in dGEMRIC index was seen at 6-month compared to baseline in KLG0. Further analysis of remaining subjects and time points may help in planning future clinical trials

14:48 127. Comparison of Quantitative Imaging of Cartilage for Osteoarthritis: T2, T1rho, DGEMRIC, and Contrast-Enhanced CT Carmen Taylor1, Julio Carballido-Gamio1, Sharmila Majumdar1, Xiaojuan Li1 1UCSF, San Francisco, California , USA

This work compares MRI (T1, T2, T1rho) and contrast-enhanced CT in human osteoarthritic articular cartilage, in the presence and absence of gadolinium-based contrast agent. T2 values correlated moderately well with postcontrast T1 and T1rho values. Postcontrast T1 was found to correlate equivalently well with T1rho and T2, but contrast-enhanced CT values correlated better with T1rho and postcontrast T1 better than T2. Both T1rho and T2 values were significantly different before and after contrast addition.

15:00 128. Evaluation of Cartilage Repair with T2 and DGEMRIC Up to Two Years After Autologous Chondrocyte Transplantation Lauri Mattila1, Jatta E. Kurkijärvi2, Risto Ojala1, Marianne Haapea1, Osmo Tervonen1, 3, Ilkka Kiviranta4, Miika T. Nieminen1, 3 1Oulu University Hospital, Oulu, Finland; 2University of Kuopio, Kuopio, Finland; 3University of Oulu, Oulu, Finland; 4Helsinki University Hospital, Helsinki, Finland

Autologous chondrocyte transplantation (ACT) is a method for repairing focal chondral defects. Combined T2 relaxation time measurements and dGEMRIC at 1.5T were used to study ACT repair at 5±1, 12±2 and 23±1 months after the ACT operation. T2 measurements suggest that the collagen orientation of ACT graft tissue has not regained the 3-D collagen architecture typical to articular cartilage in two years. Proteoglycan replenishment, as measured by dGEMRIC, can reach normal levels during the first six months after the operation and significant changes in PG levels may not occur thereafter.

15:12 129. Magnetization Transfer Contrast and T2 Relaxation in the Evaluation of Cartilage Repair Tissue at 3T MRI Goetz Hannes Welsch1, Siegfried Trattnig1, Sebastian Quirbach1, Stefan Marlovits1, Stephan Domayer1, Oliver Bieri2, Klaus Scheffler2, Tallal Charles Mamisch3 1Medical University of Vienna, Vienna, Austria; 2University of Basel, Basel, Switzerland; 3University of Berne, Berne, Switzerland

Magnetization Contrast Imaging (MTC) has shown its benefits in neuroradiology, however it also has its potential in musculoskeletal-MRI of cartilage repair tissue. The purpose of this initial study was to show the potential of MTC in the assessment of healthy articular cartilage as well as cartilage repair tissue after different cartilage repair procedures and compare it to widely used T2 mapping at 3 Tesla MRI. Furthermore as a visible zonal variation has been seen to add additional information in T2 relaxation evaluation of articular cartilage, within MTC deep and superficial cartilage aspects were assessed to elucidate a possible zonal difference.

15:24 130. Effect of Joint Loading on T2 Relaxation and DGEMRIC of Knee Cartilage in Marathon Trainers Miika T. Nieminen1, 2, Outi Parviainen1, Marianne Haapea1, Tatu Kokkonen3, Juha Isolehto4, Ilkka Kiviranta3 1Oulu University Hospital, Oulu, Finland; 2University of Oulu, Oulu, Finland; 3Helsinki University Hospital, Helsinki, Finland; 4University of Jyväskylä, Jyväskylä, Finland

The effect of intensive long-term running training on articular cartilage was studied in human marathon trainers. T2 relaxation time and dGEMRIC measurements at 1.5T were performed at baseline and 6-months follow-up, controlled by biomechanical joint loading measurements. Training resulted in subtle but significant local changes in T2 and dGERMIC in the femoral and tibial load bearing compartments. The T2 results show a trend towards prolonged values after intensive training but also when the quality of loading is stressful for the joint.

15:36 131. Quantitative T2 Mapping of Knee Cartilage: Initial Results on the Differentiation of Healthy and Altered Articular Cartilage of the Knee by Means of Unloading Tallal Charles Mamisch1, Goetz Hannes Welsch2, Sebastian Quirbach2, Stefan Marlovits2, Siegfried Trattnig2 1University of Berne, Berne, Switzerland; 2Medical University of Vienna, Vienna, Austria

The biomechanical constitution of articular cartilage is changed during loading. However these changes are reported to diminish during unloading. The aim of this study was to use quantitative cartilage T2 mapping and its zonal assessment for the evaluation of unloading during a one hour MR scan as a potential new tool in the differentiation of healthy and altered articular cartilage within the knee. In an initial study, a subtraction of the pre- and post-unloading T2 maps could visualize cartilage changes between healthy cartilage and cartilage defects or cartilage repair tissue.

15:48 132. Cartilage Deformation Under Load in a Human Cadaveric Hip Measured with 7.0T QMRI Laura L. Greaves1, Michael Gilbart1, Andrew Yung1, Piotr Kozlowski1, David R. Wilson1 1University of British Columbia, Vancouver, Canada

The feasibility and repeatability of measuring cartilage deformation at the hip under a physiological load was assessed with 7.0T qMRI. A human cadaveric hip was axially compressed in a custom pneumatic loading device. Imaging was performed with a fat-suppressed 3D FLASH sequence and a resolution of 0.11x 0.11 x 1 mm was achieved. Mean cartilage compression was 0.71 mm (34%) after 3 hr 45 min, error due to repeatability was 0.13 mm (3.4%). We successfully measured cartilage deformation in the hip and the overall magnitude of deformation was far greater than our resolution and error due to repeatability.

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Improving Data Quality for Diffusion Imaging Room 801 A/B 16:30-18:30 Chairs: Peter B. Kingsley and Carlo Pierpaoli

16:30 133. An Eddy-Current-Compensated Diffusion-Weighting Preparation Based on a Single Spin Echo Jürgen Finsterbusch1, 2 1University Medical Center Hamburg-Eppendorf, Hamburg, Germany; 2Neuroimage Nord, Hamburg-Kiel-Lübeck, Germany

A double-spin-echo preparation is commonly used in diffusion-weighted MR to minimize artifacts caused by eddy currents, e.g. geometric distortions in echo-planar imaging. However, due to the two refocusing RF pulses required, it is at the expense of a higher sensitivity to RF inhomogeneieties that are in particular pronounced at higher static magnetic fields. An extension of the Stejskal-Tanner experiment is presented that introduces a third gradient lobe prior to the RF refocusing pulse. As the double-spin-echo preparation, it is able to compensate eddy currents of a given decay constant for appropriate gradient durations but is less sensitive to RF inhomogeneieties.

16:42 134. Single Step Non-Linear Diffusion Tensor Estimation in the Presence of Microscopic and Macroscopic Motion Murat Aksoy1, Chunlei Liu1, Michael Moseley1, Roland Bammer1 1Stanford University, Stanford, California , USA

Due to its long acquisition time, DTI can suffer considerably from artifacts introduced by patient motion. Thus far, the correction of motion artifacts in DTI has been focused mostly to correcting for miniscule motion and avoiding ghosting artifacts. However, for the accuracy of the reconstructed diffusion tensors, gross patient motion should also be accounted for. While a simple registration operation is sufficient for single-shot data, for multi-shot sequences, the correction of gross patient motion requires accounting for the altered diffusion encoding direction between successive k-space interleaves. In this study, we investigated the combined effect of microscopic and macroscopic motion on the k-space data and proposed a single step non-linear optimization algorithm that reconstructs the diffusion tensors directly from k-space data in the presence of microscopic and macroscopic motion.

16:54 135. Reducing Distortions in DW-EPI with a Dual-Echo Blip-Reversed Sequence Daniel Gallichan1, Jesper L R Andersson1, Mark Jenkinson1, Matthew D. Robson1, Karla L. Miller1 1University of Oxford, Oxford, UK

DW-EPI is intrinsically affected by distortions due to inhomogeneities in the B0 field. Parallel acceleration reduces these distortions, but does not remove them entirely. We propose the addition of a second spin-echo in the accelerated pulse sequence with the phase encode blips in the opposing direction to the first echo. This allows a blip-up-blip-down reconstruction of the corrected image with a vastly reduced scan time compared to acquiring the images separately.

17:06 136. Crossing Fibers, Diffractions and Non-Homogeneous Magnetic Field: Correction of Artifacts by Bipolar Gradient Pulses Amnon Bar-Shir1, Yoram Cohen1 1Tel-Aviv University, Tel-Aviv, Israel

Recently, several approaches were suggested for increasing the accuracy of determining fiber orientations, especially those of crossing-fibers. Therefore there is a need for complex phantoms to challenge different indices extracted from the different diffusion MR techniques used. In the present study we describe several micron-scale phantoms of increasing complexity and decreased homogeneity. Our results demonstrate the effect of background gradients on the expected diffraction patterns observed in high b-value q-space NMR. We showed that bipolar diffusion gradients can reduced such artifacts suggesting the use of bipolar diffusion gradients in clinical diffusion MRI.

17:18 137. Partial-Volume Modelling in Diffusion MRI Stephen Smith1, Jennifer McNab1, Karla Miller1 1FMRIB, Dept. Clinical Neurology, UK

In diffusion-based analyses of white-matter integrity (e.g., using fractional anisotropy (FA) as the primary marker), it is of concernthat many tracts of interest have thickness on the same order as thedata resolution; an apparent change in FA could be due to either achange in tract thickness (extent of partial-voluming) or a change inthe underlying “true” FA (and that in itself can vary as a result ofdiffering mixtures of crossing fibres). In this work we use veryhigh-resolution diffusion data in order to test whether disambiguationof FA changes and tract thickness might be possible. We use thehigh-resolution data as the “gold-standard”, from which to generatedata at more normal resolutions for which the underlying ground-truthis known. We demonstrate the nonlinearities in the generation of theapparent FA seen at normal resolutions, and attempt to recover theunderlying true FA from down-sampled data, even in thinner tracts.

17:30 138. Free Water Extraction from Diffusion Images Ofer Pasternak1, Nir Sochen, Nathan Intrator1, Yaniv Assaf, 2 1Tel Aviv University, Tel Aviv, Israel; 2The Whol Institute for Advanced Imaging of the Tel Aviv Sourasky Medical Center, Israel

We propose a method to map and then eliminate free water from diffusion images. While free water contamination is often neglected for healthy brain imaging, it is of high importance to be eliminated for the case of cerebral edema. Our method separates the free water compartment from the remaining, contamination free, brain tissue compartment. The latter can then be analyzed by DTI methods such as FA and tractography. In addition, a free water mapping of the brain is obtained. We present the enhancement of FA and tractography on the free water eliminated data, collected by a regular DTI acquisition.

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17:42 139. Regional Distribution of Outliers of Diffusion MRI in the Human Brain Lindsay Walker1, Jinzhong Yang2, Xiaoying Wu2, Kristina Simonyan1, Ragini Verma2, Carlo Pierpaoli1 1NIH, Bethesda, Maryland, USA; 2University of Pennsylvania, Philadelphia, Pennsylvania, USA

The presence of outliers in the diffusion weighted images (DWI) used for DTI of the human brain affects tensor derived quantities such as anisotropy and trace(D). We present a preliminary analysis of the regional distribution of outliers in the brain of a population of 20 healthy volunteers using the RESTORE robust tensor fitting algorithm. An outlier rejection probability map is produced showing that the occurrence of outliers is regionally consistent within the population. This implies a regionally varying statistical power across the brain, which should be considered when performing both ROI-based and voxelwise analysis of DTI data.

17:54 140. To Rotate B or Not to Rotate B? the Importance of Reorienting the B-Matrix During Motion Correction of DT-MRI Data Alexander Leemans1, Christopher John Evans1, 2, Derek K. Jones1 1School of Psychology, Cardiff University, Cardiff, UK; 2GE Healthcare, Chalfont St. Giles, UK

To estimate DTI measures, such as FA, it has been shown that the acquisition of a higher number of DW gradient directions is needed. Consequently, acquisition times are longer, increasing the adverse effect of subject motion. Although previous research indicates that correcting for such motion artifacts improves the accuracy of the FA, it remains debatable whether rotating the b-matrix (during subject motion correction) can further improve the estimation of the diffusion tensor. In this context, we investigated the effect of such a b-matrix rotation on the FA and the first eigenvector, and looked at the consequences for fiber tractography.

18:06 141. Improved SNR in Diffusion Spectrum Imaging with Statistical Reconstruction Justin P. Haldar1, Van J. Wedeen2, Marzieh Nezamzadeh3, Guangping Dai2, Norbert Schuff3, Zhi-Pei Liang1 1University of Illinois at Urbana-Champaign, Urbana, Illinois, USA; 2Harvard Medical School, Charlestown, Massachusetts, USA; 3University of California San Francisco, San Francisco, California , USA

Diffusion spectrum imaging (DSI) is a powerful technique for the characterization of complex tissue microarchitecture. However, the potential of this technique has not been fully utilized for high-resolution biological studies because of long acquisition times and limited signal-to-noise ratio. This paper presents a new approach for reconstructing DSI images, using a statistical model that takes advantage of the high level of spatial-spectral correlation in DSI images. This method can provide significant improvements in signal-to-noise ratio relative to conventional techniques, revealing additional structures in DSI data which have previously been hidden by noise.

18:18 142. Quality Assessment of DTI-Based Muscle Fiber Tracking Anneriet M. Heemskerk1, Tuhin K. Sinha1, Kevin J. Wilson1, Zhaohua Ding1, Bruce M. Damon1 1Vanderbilt University, Nashville, Tennessee, USA

DTI-based muscle fiber tracking enables reconstruction of muscle architecture but no methods currently exist to access the quality of fiber tracking. We propose a method to determine the quality of individual tracts based on the location of the fibers points of termination, paths, lengths, and similarity to neighboring fibers. Inaccurate fibers tended to be grouped, which can be expected if there are similar, spatially dependent underlying causes. We found that on average 77% of the fiber tracts generated in the tibialis anterior muscle met our quality assessment criteria.

Transmit Concepts & Arrays Room 718 A 16:30-18:30 Chairs: Gregor Adriany and Steven M. Wright

16:30 143. A Comparison of Matching Strategies for RF Transmission Arrays Based on Network Theory David Otto Brunner1, Nicola De Zanche1, Klaas Paul Pruessmann1 1University and ETH Zurich, Zurich, Switzerland

RF transmission arrays are used in various forms in order to mitigate inhomogeneous RF excitation or accelerate spatially selective pulses. Since multiple ports must be fed by power amplifiers, the power loss is not only given by the reflection coefficient of each port but also by the coupling among ports. In this work we study the impact of different types of single-port matching setups on the coupling and on the power loss for different applications such as RF shimming and Transmit SENSE.

16:42 144. A Simplified 16-Channel Butler Matrix for Parallel Excitation with the Birdcage Modes at 7T Vijayanand Alagappan1, 2, Kawin Setsompop3, Juergen Nistler4, Andreas Potthast5, Franz Schmitt4, Elfar Adalsteinsson3, Lawrence L. Wald1 1Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, USA; 2Tufts University, Charlestown, Massachusetts, USA; 3MIT, Cambridge, Massachusetts, USA; 4Siemens Medical Solutions, Erlangen, Germany; 5Siemens Medical Solutions, Charlestown, USA

A Butler matrix drives the individual rungs in linear combinations to form the well know uniform birdcage mode and higher gradient modes potentially capturing a majority of the sensitivity and acceleration capabilities in a subset of the channels. In this work we develop and test a simplified 16-channel high-power Butler matrix at 300 MHz with a 16 channel transmit/receive stripline array coil.

16:54 145. An Extensible Transmit Array System Using Vector Modulation and Measurement Pascal Stang1, Adam Kerr1, John Pauly1, Greig Scott1 1Stanford University, Stanford, California , USA

Transmit arrays offer important enhancements including improved RF fidelity, selectivity, and pulse acceleration. However, significant challenges remain in the hardware implementation of Tx array systems, and their integration with existing scanners. We present a 4-channel modular expandable vector-modulated transmit array system that can be easily adapted to most scanners. Our system also incorporates coil current sensors and RF instrumentation to permit automated measurement and feed-forward compensation for coil coupling and other non-ideal RF effects. We successfully perform coil decoupling, static-vector B1-shimming, and a ‘spokes’ fully-parallel transmit sequence.

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17:06 146. General Signal Vector Decoupling for Transmit Arrays Greig C. Scott1, Pascal Stang1, Adam Kerr1, John Pauly1 1Stanford University, Stanford, USA

In transmit arrays, control of coil coupling is much more difficult to control. However, a linear basis of signal vectors always exists to uniquely excite each coil. Using an integrated vector modulator/vector analyzer system, we present a general signal vector calibration technique that works in transmit-only and transceive coils that lack the ability to PIN switch individual coils. Practical sensor issues are also addressed.

17:18 147. Intrinsically Decoupled Current CONtrolled Transmit and Receive (2CONTAR) Coil Elements for Arbitrarily Arranged Transceive Coil Arrays Evgenia Kirilina1, Thomas Riemer2, Frank Seifert3 1Physikalisch Technische Bundesanstalt , Berlin, Germany; 2IZKF University if Leipzig, Leipzig, Germany; 3Physikalisch Technische Bundesanstalt, Berlin, Germany

Transmit coil arrays are usually driven by voltage sources with fixed source impedance. Due to mutual inductance this inherently leads to a coupling of the individual coil elements within the array resulting in RF field distortions during transmission and inappropriate sensitivity profiles during reception. In this contribution we present a novel parallel driven current controlled transmit/receive array. It combines the current source decoupling for transmission with a transmit/receive switch to apply the well established preamplifier decoupling for reception. Avoiding complicated feedback circuits a coil array is implemented which guarantees full control over the RF fields within the object.

17:30 148. A Close-Fitting 7 Tesla 8 Channel Transmit/Receive Helmet Array with Dodecahedral Symmetry and B1 Variation Along Z Graham C. Wiggins1, Azma Mareyam1, Kawin Setsompop2, Vijay Alagappan1, Andreas Potthast3, Lawrence L. Wald1, 4 1Massachusetts General Hospital, Charlestown, Massachusetts, USA; 2MIT, Cambridge, Massachusetts, USA; 3Siemens Medical Solutions,Inc, Charlestown, Massachusetts, USA; 4Harvard-MIT Division of Health Sciences and Technology, Cambridge, Massachusetts, USA

An 8 channel transmit/receive array has been constructed based on 8 of the 12 pentagonal faces of a dodecahedron. The pentagonal loop elements are capacitively decoupled at their common edges. The array forms a close-fitting helmet with high transmit efficiency and good receive sensitivity. The coil elements form spatially distinct B1 transmit profiles which also vary along Z, which should allow greater control of the excitation profile throughout the brain.

17:42 149. Hybrid TEM/Loop Coil Array for Parallel High Field MRI Jan Paska1, Christoph Leussler2 1Technical University of Hamburg-Harburg, Hamburg, Germany; 2Philips Research Europe Hamburg, Hamburg, Germany

We investigated the advantages of a new type of coil. We present a coil array consisting of hybrid TEM/loop coil elements. The single hybrid coil element is intrinsically decoupled, and therefore no additional decoupling circuitry is necessary. The hybrid coil array, as compared to TEM or loop coil arrays, has additional degrees of freedom to achieve a uniform RF-excitation. The coil array is also suitable for parallel imaging techniques due to the orthogonal fields. Since each hybrid coil element has an own RF-shield it is configurable and can be used for imaging of different body parts.

17:54 150. Switchable Short Quadrature Body Coil with Two Axial Uniformity Modes Zhiyong Zhai1, Gordon DeMeester1, Michael Morich1, Robert Gauss1, Paul Harvey2 1Philips Medical Systems, Cleveland, Ohio, USA; 2Philips Medical Systems, Netherlands

For compact high field MRI systems such as at 3T, it is desirable to have a short quadrature body coil (QBC). A short QBC has the advantages of less required peak power, less exposed RF power for a patient and less SAR than a longer QBC. Typically a QBC is a shielded birdcage coil. Shortening the QBC has some impact on the axial uniformity and, in a few applications, a more uniform transmit field can be beneficial. Here we describe a switchable QBC which can switch between a short and long uniformity mode as needed. As an example, the Finite Difference Time Domain (FDTD) method is used to calculate B1-field for a switchable 3T QBC.

18:06 151. A Novel 8-Channel Transceive Volume-Array for a 9.4T Animal Scanner Ewald Weber1, Bing Keong Li1, Feng Liu1, Yu Li1, Peter Ullmann2, Hector Sanchez Lopez1, Stuart Crozier1 1The University of Queensland, Brisbane, Australia; 2Bruker BioSpin MRI GmbH, Germany

This work focuses on the design of a novel 8-element transceive volume-array for high field animal MRI. A dedicated, shielded 8-element transceive volume-array for large rat MRI applications at 9.4T, has been developed and constructed. Preliminary phantom images acquired using this prototype show that homogenous B1 fields can be attained. In addition, the Transmit SENSE images obtained reveal that the design of this transceive volume array is well suited for accelerated spatially-selective excitation and that it worked well with GRAPPA.

18:18 152. Whole Body Imaging at 7T with a 16 Channel Body Coil and B1 Shimming Thomas Vaughan1, Lance DelaBarre1, Carl Snyder1, Silvia Mangia1, Jinfeng Tian2, Matthew Waks2, Scott Shillak2, Labros Petropoulos2, Gregor Adriany1, Peter Andersen1, John Strupp1, Kamil Ugurbil1, 3 1University of Minnesota, Minneapolis, Minnesota, USA; 2MR Instruments, Inc., Minneapolis, Minnesota, USA; 3Max Planck Institute for Cybernetics, Tubingen, Germany

Of the thirty 7T whole body MRI systems installed or on order, none are equipped for whole body imaging with body coils. RF artifacts and SAR are two of the challenges to be met before body coil imaging is possible. In this work, a 16 channel TEM body coil system was developed and applied to whole body, 7T imaging. B1 shimming methods developed in-house were used to correct RF artifacts in anatomic ROIs. By this technology and method, whole body imaging with body coils appears feasible at 7T.

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Brain Activation Studies at High Spatial Resolution Room 718 B 16:30-18:30 Chairs: David Ress and Alice M. Wyrwicz

16:30 153. Positive and Negative BOLD-Signals from Blood Vessels in Monkey Visual Cortex Jozien Goense1, Nikos Logothetis1, 2 1Max-Planck Institute for Biological Cybernetics, Tuebingen, Germany; 2University of Manchester, Manchester, UK

High-resolution fMRI can aid in determining to what extent the BOLD signal arises from capillaries or larger vessels. In high-resolution functional activation maps both positive and negative BOLD signals associated with vessels were observed; this was seen for both GE- and SE-BOLD. Because of its higher specificity, the SE-BOLD signal was used to investigate the origin of these vessel signals. The location of the SE-BOLD signal from veins changed when the direction of the gradients was changed. This is in contrast to the peak SE-BOLD occurring in layer IV which arises from capillaries, and was insensitive to gradient reversal.

16:42 154. Spatiotemporal Dynamics of BOLD and CBV Responses at Submillimeter Columnar Resolution Seong-Gi Kim1, Chan-Hong Moon1, Mitsuhiro Fukuda1 1University of Pittsburgh, Pittsburgh, Pennsylvania, USA

To understand the vascular source of functional signals which are specific to neuronal activity, it is critical to examine spatiotemporal characteristics at high resolution. We examined BOLD and CBV signals in a well-established cat orientation column model. Orientation-specific BOLD signal is minimal, while orientation-specific CBV response is significant, but increases slowly compared to non-specific BOLD and CBV signals. This indicates that the orientation-specific signal originates from microvessels including capillaries.

16:54 155. Orientation Maps in Ferret Visual Cortex Measured by Multi-Slice FMRI Junjie V. Liu1, Mriganka Sur1, Christopher I. Moore1, Jitendra Sharma1, 2 1Massachusetts Institute of Technology, Cambridge, Massachusetts, USA; 2Martinos Imaging Center, Charlestown, Massachusetts, USA

We present the first measurements of high-resolution (200 um) orientation maps in visual cortex of the ferret, using multi-slice gradient-echo EPI (without contrast agent). A novel coil pocket glued on top of skull near visual cortex is used. Orientation maps are measured in 3-4 slices parallel to cortical surface near V1, and are comparable to maps measured by optical imaging. The laminar profiles of BOLD signals show that the orientation-specific responses are relatively uniform across cortical layers, whereas the non-specific visually-driven responses are stronger near superficial layers.

17:06 156. Spatial Scale Estimation of Columnar Neuronal Activity in Cats’ Visual Cortex Based on the Analysis of Ultra-High-Resolution CBV-Weighted FMRI Xu Chen1, Fuqiang Zhao2, Seong-Gi Kim2, Jean Tkach1, Stephen Strother3, 4 1Case Western Reserve University, Cleveland, USA; 2University of Pittsburgh, Pittsburgh, Pennsylvania, USA; 3Baycrest, Toronto, Canada; 4University of Toronto, Canada

The spatial scale of neural representation structures plays an important role in neuro-imaging studies and is in itself a booming area of research. In this abstract, we demonstrate a framework to estimate the spatial scale of columnar neuronal activity in a cat's primary visual cortex based on the analysis of ultra-high-resolution CBV-weighted functional MRI (fMRI) data. With matched filter theorem as its rationale, this framework takes advantage of the distribution of the reproducibility between spatial patterns from re-sampled fMRI datasets and has the potential to be extended to estimate the spatial scale of other important neuronal activities.

17:18 157. Multi-Resolution Classification Analysis of Ocular Dominance Columns Obtained from Human V1 at 7 Tesla: Mechanisms Underlying Decoding Signals Amir Shmuel1, 2, Guenter Raddatz1, Denis Chaimow1, Nikos Logothetis1, Kamil Ugurbil, 12, Essa Yacoub3 1Max Planck Institute for Biological Cybernetics, Tuebingen, Germany; 2University of Minnesota, Minneapolis, Minnesota, USA; 3University of Minnesota, Minneapolis, USA

Recent studies have demonstrated that classification algorithms applied to human fMRI data can decode information segregated in cortical columns, although the voxel-size was large relative to the width of columns. The mechanism by which low-resolution imaging decodes information represented at higher resolution is not clear. We show that using GE-fMRI signals, the mechanism underlying the decoding signals involves contributions from both gray matter and macroscopic blood vessels. We hypothesize that draining regions biased towards columns with preference to one eye underlie the specificity of vessels. Decoding at high-resolution is superior to low-resolution when applied to data from small cortical volumes.

17:30 158. Layer-Specific Blood-Volume MRI of the Retina Govind Nair1, Yoji Tanaka1, Tsukasa Nagaoka1, Machelle T. Pardue2, Darin Olson2, Peter Thule2, Timothy Q. Duong1 1Emory University, Atlanta, Georgia, USA; 2VA hospital, Atlanta, Georgia, USA

The thin retina is organized into multiple cell layers and two vascular layers. The retinal and choroidal vasculatures are located on either side of the retina with an avascular photoreceptor layer in the middle. Importantly, the two vascular layers independently regulated and respond differently to physiologic stimulations. The retina’s remarkable anatomical and functional layout lends itself to be an excellent model for testing layer-specific MRI. We recently reported multiple anatomical layers and unique layer-specific BOLD fMRI responses in the retina. In this study, we extend previous findings to include layer-specific blood-volume MRI and layer-specific physiologically evoked BV changes.

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17:42 159. High Resolution Functional MRI Imaging of Material-Specific Visual Processing in Thalamic Nuclei Wendy Ringe1, Kaundinya Gopinath1, Sergey Cheshkov1, Subhendra Sarkar1, Richard Briggs1, Robert Haley1 1UT Southwestern Medical Center, Dallas, Texas, USA

Converging evidence indicates that thalamic nuclei are specifically involved in category-dependent processing which may not be resolvable with conventional fMRI voxel sizes. High resolution fMRI demonstrated material-specific activation in each of four material types: Words, Objects, Faces, Nature Scenes. Each activated bilateral medial dorsal nucleus, with additional activation of: Words - left inferior pulvinar, anterior, ventral lateral, and ventral posterior nuclei; Nameable Objects - left ventral lateral, ventral posterior and right inferior pulvinar and ventral lateral nuclei; Faces - left inferior pulvinar and ventral lateral and right anterior nuclei; Nature Scenes - bilateral pulvinar and right ventral posterior nuclei.

17:54 160. Functional MRI Mapping of Laminar Structures in Cat Lateral Geniculate Nucleus Nanyin Zhang1, Xiao-Hong Zhu1, Jae-keun Park1, Yi Zhang1, Ye Li1, Wei Chen1 1University of Minnesota, Minneapolis, Minnesota, USA

Lateral geniculate nucleus (LGN) is the most important component in the thalamus in relaying visual information flow from the retina to primary visual cortex (V1). In this study, we demonstrate the feasibility of mapping the LGN laminar structures in cat using BOLD-based and CBV-MION-based functional magnetic resonance imaging. Both BOLD and CBV data successfully differentiate individual laminae is LGN. The maps generated using BOLD and MION signals are highly reproducible for intra-subject comparison. In addition, the results suggest CBV signal has significant narrower point spread function compared to BOLD signal.

18:06 161. Visualization of Distinct Functional Cortical Units Using Kernel Principal Component Analysis of FMRI Data Xiaomu Song1, 2, Limin Li1, 2, Daniil Aksenov1, Alice M. Wyrwicz1, 2 1Evanston Northwestern Healthcare Research Institute, Evanston, Illinois, USA; 2Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA

This abstract introduces a novel method to detect and visualize distinct functional cortical units in rabbits' brain using kernel principal component analysis of high field fMRI data. In the abstract, the research background and motivation are first introduced, followed by the two sections describing the imaging and data analysis method. After presenting the experimental results showing activation maps and temporal profiles, the final conclusions are made.

18:18 162. Pushing the Spatial Resolution of BOLD Imaging, the FMRI Cortical Representation of Rat Digits at 9.4T Christopher Paul Pawela1, Dan L. Shefchik1, Younghoon R. Cho1, Rupeng Li1, Seth R. Jones1, Ji-Geng Yan1, Safwan S. Jaradeh1, Hani S. Matloub1, James S. Hyde1 1Medical College of Wisconsin, Milwaukee, USA

High resolution Gradient Echo BOLD images were acquired of the rat somatosensory cortex at 9.4 T. We were able to resolve the representations of the individual digits and the data showed a high degree of layer specificity.

Prostate Cancer: Evolving Detection Techniques Room 714 A/B 16:30-18:30 Chairs: Jelle O. Barentsz and Amita Shukla-Dave

16:30 163. Young Investigator Award Finalist: Magnetic Resonance Diffusion Characteristics of Histologically Defined Prostate Cancer in Humans Junqian Xu1, Peter A. Humphrey1, Adam S. Kibel1, Abraham Z. Snyder1, Vamsidhar R. Narra1, Joseph JH Ackerman1, Sheng-Kwei Song1 1Washington University, St. Louis, Missouri, USA

Increased cellularity, and hence decreased luminal spaces, in peripheral zone PCa led to about 40% and 50% ADC decrease compared to benign peripheral zone tissues in vivo and ex vivo, respectively. In contrast, no significant diffusion anisotropy differences were observed between the cancerous and non-cancerous peripheral zone tissues. However, the dense fibromuscular tissues in prostate, such as stromal tissues in benign prostatic hyperplasia (BPH) in central gland, exhibited high diffusion anisotropy. PCa identified in volume rendered diffusion sensitive MR images correlates well with histologically determined PCa foci.

16:50 164. Reproducibility of Quantitative and Semi-Quantitative Dynamic and Intrinsic Susceptibility-Weighted Parameters of the Cancerous Human Prostate Gland Roberto Alonzi1, Jane Taylor1, Peter Hoskin1, James Stirling1, James d'Arcy2, Ben Wilton2, David Collins2, Michele Saunders1, Anwar Padhani1 1Mount Vernon Hospital, Northwood, UK; 2Institute of Cancer Research, Sutton, UK

Quantitative functional MRI techniques are increasingly being used in the assessment of the malignant prostate gland. For these techniques to have clinical application, their reproducibility needs to be established. 20 patients with prostate cancer that were due to be treated with neo-adjuvant androgen deprivation (AD) prior to radical radiotherapy underwent 2 paired MRI investigations; two prior to the commencement of and two scans after three months of AD. This study is the first to document the variability and reproducibility of T1-and T2*-weighted DCE-MRI and R2* for the benign and malignant human prostate gland.

17:02 165. Correlation of ADC and T2 with Cell Density in Prostate Cancer at 3.0T Peter Gibbs1, Gary P. Liney1, Martin D. Pickles1, Bashar Zelhof1, Greta Rodrigues2, Lindsay W. Turnbull1 1University of Hull, Hull, UK; 2Hull and East Yorkshire NHS Trust, Hull, UK

Prostate cancer rates have risen dramatically over the last few years and MRI is increasingly used in this area. With a diagnostic accuracy of only around 70% conventional high spatial resolution and dynamic contrast enhanced imaging has been supplemented with DWI and T2 mapping. However, there has been little investigation of the diagnostic potential of these parameters via correlation with pathological data. This work concentrates on comparing cell density determined from hematoxylin and eosin staining with ADC and T2 values.

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17:14 166. The Impact of Intermixed Normal Peripheral Zone Elements on the Measurement of Apparent Diffusion Coefficient and T2 in Prostate Cancers Deanna Lyn Langer1, 2, Theodorus H. van der Kwast1, 3, Andrew J. Evans1, Laibao Sun4, Martin J. Yaffe, 24, John Trachtenberg1, Masoom A. Haider1, 2 1University Health Network, Toronto, Canada; 2University of Toronto, Toronto, Canada; 3Mount Sinai Hospital, Toronto, Canada; 4Sunnybrook Health Sciences Centre, Toronto, Canada

The impact of normal peripheral zone (PZ) tissue components within prostate cancers on ADC and quantitative T2 values was investigated. Whole mount sections were compared to MRI. PZ cancers were classified as sparse or dense according to the percentage of normal PZ tissue in the tumor. ADC and T2 values from ROIs in normal PZ, dense cancers and sparse cancers were compared. There were no statistically significant differences seen between normal PZ and sparse cancers for absolute values or contrast (tumor to normal ratio) measurements in both ADC and T2, whereas normal PZ was significantly higher than dense cancer. The percentage of normal PZ within a tumor may affect the detection and delineation of prostate cancer.

17:26 167. Sensitivity and Specificity of Functional MRI to Map Tumour Hypoxia in the Human Prostate Gland Roberto Alonzi1, Anwar Padhani1, Jane Taylor1, James Stirling1, Ben Wilton2, James d'Arcy2, David Collins2, Michele Saunders1, Peter Hoskin1 1Mount Vernon Hospital, Northwood, UK; 2Institute of Cancer Research, Sutton, UK

A study in 17 patients with prostate cancer evaluating the value of incorporating Dynamic Susceptibility Contrast (DSC) MRI based blood volume measurements with BOLD imaging to detect tumour hypoxia. Patients were imaged with BOLD and DSC MRI prior to radical prostatectomy. Hypoxia was determined using pimonidazole immunohistochemistry. The sensitivity and specificity for hypoxia detection was 80% and 77% respectively

17:38 168. Assessment of Different Quantification Approaches of DCE-MRI in Prostate Cancer at 3T Guang Jia1, Xiangyu Yang1, Yukihisa Takayama1, Steffen Sammet1, Zarine K. Shah1, Ketul K. Shah1, Pankaj Dangle1, Wenle P. Wang1, Rafael E. Jimenez1, Vipul R. Patel1, Michael V. Knopp1 1The Ohio State University, Columbus, Ohio, USA

Improving the non-invasive capabilities of cancer delineation might be achieved by dynamic contrast-enhanced MRI at high field. 27 patients with clinically proven prostate cancer were imaged at 3T without using an endorectal coil. 3 different methods including semi-quantitative parameters, adjusted Brix’s model and Larsson’s model were applied to the ROIs from tumor, non-cancerous peripheral zone, central gland. All parameters could differentiate tumor from the non-cancerous peripheral zone. However, only tmax, washout-score, kep could differentiate tumor from central gland. In conclusion, DCE-MRI at 3T is capable of non-invasively detecting prostate cancer especially from the central gland by selecting appropriate parameters.

17:50 169. Functional MR Parameters of Histopathologically Indentified Prostate Tissues Sophie F. Riches1, Veronica A. Morgan1, Geoffrey S. Payne1, Cyril Fisher2, S Sandhu2, David J. Collins1, Nandita M. deSouza1 1Royal Marsden NHS Trust & Institute of Cancer Research, Sutton, UK; 2Royal Marsden NHS Trust, London, UK

20 patients were imaged prior to prostatectomy using diffusion imaging, contrast enhanced MRI and 1H spectroscopy. Histopathology-defined tumour regions were transferred onto parametric maps to obtain values for normal and tumour tissue for T2 intensity, apparent diffusion coefficient, area under the contrast uptake curve, contrast volume transfer coefficient, reflux rate constant and the ratio of choline to citrate peak area. Significant differences were identified between the mean functional parameters of tumour and combined non tumour tissue, and between tumour and normal peripheral zone. No difference was found between tumour and normal central gland unless small tumour regions were excluded.

18:02 170. Magnetic Resonance Spectroscopic Imaging and Dynamic Contrast Enhanced Prostate MRI: Correlation with Histopathology Bao Zhang1, Steve Roys1, Khan Siddiqui2, Danielle Holanda, John Papadimitriou, James Borin, Michael Naslund, Eliot Siegel, Rao P. Gullapalli 1University of Maryland, Baltimore, Maryland, USA; 2VA Maryland Health Care System, Baltimore, Maryland, USA

Conventional magnetic resonance (MR) imaging, along with 3D-MR spectroscopy imaging (MRSI) and dynamic contrast enhanced (DCE) MRI were performed on fourteen patients with biopsy proven prostate cancer prior to prostatectomy. Parameters derived from these techniques were compared with step section histopathology. Results showed that both techniques are able to distinguish cancerous tissue from normal but they however lacked sensitivity to tumor grade. Receiver operating characteristic (ROC) based statistical analysis revealed a positive predictive value of 0.95 and 0.94 respectively and an overall accuracy of 72% and 65% respectively.

18:14 171. Comparison of Transceive Endorectal and External Surface Array Coils for Prostate Imaging at 7 Tesla Gregory John Metzger1, Carl J. Snyder1, Can Akgun1, Gregor Adriany1 1University of Minnesota, Minneapolis, Minnesota, USA

Previous work by our group addressed the challenges associated with performing ultra high field prostate imaging with external transceive surface arrays. In this abstract, we pursue a preliminary study which investigates how the external coil array performs against a transceive endorectal coil (ERC) at 7 Tesla. It was found that the ERC produced the expected gains in SNR along with improved anatomic detail on T2w TSE imaging. While improvements in image quality were observed the challenges of managing the large transmit B1 homogeneities of a local transceive coil requires further investigation.

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Advances in MRI-Based Cell Tracking Room 716 A/B 16:30-18:30 Chairs: Jeff W. M. Bulte and Gustav Jacob Strijkers

16:30 172. High Resolution Imaging of Arterially Delivered Mesoangioblasts Min Liu1, Qing Yang1, Bijoy Thattaliyath1, Giulio Cossu2, Sean Germain1, Glenn Adam Walter1 1University of Florida, Gainesville, Florida, USA; 2Stem Cell Research Institute, Milan, Italy

Cell based therapies represent a challenge for noninvasive monitoring due to the variability in stem cell incorporation that occurs in the presence of massive cell death. In this work MR based strategies have been developed to track the migration/integration of arterially delivered muscle stem cells into skeletal muscles and the bone marrow of dystrophic mice. Longitudinal MR tracking of mesioangioblasts was achieved following SPIO labeling of cells followed by high-resolution imaging.

16:42 173. MRI Studies of In-Vitro Perfused Human Pancreatic Islet Cell Activation Suraj Serai1, Lara Leoni2, Natalia Pablo1, Muhammad E. Haque2, Brian B. Roman, 12 1University of Illinois at Chicago, Chicago, Illinois, USA; 2University of Chicago, Chicago, Illinois, USA

Many unpredictable variables influence the outcome of human islet isolation, jeopardizing the quantity and quality of islets; and in order to improve outcome in clinical pancreatic islet isolation and functionality, various factors should be investigated thoroughly during the process of islet retrieval. Another variable factor is the number of donors. Manganese enhanced MRI is presented here as a tool to image isolated perfused human pancreatic islets. With our methods we can verify islet functionality with MR related SNR parameters. Once established, the invitro data needs to be correlated with invivo studies for enhancement in pancreas following Mn & glucose infusions.

16:54 174. A Dynamic Process of Macrophage Infiltration During Tumor Progression Yi-Hua Hsu1, Chia-Ming Shih1, Sui-Shan Lin2, Kai-Ping Chow3, Chen Chang2 1Academia Sinica, Taipei, Taiwan; 2Academia Sinica , Taipei, Taiwan; 3Chang-Gung University , Taoyuan, Taiwan

The aim of the present study is to provide insights into the role of tumor-associated macrophages (TAMs) by employing superparamagnetic iron oxide (SPIO) nanoparticles-enhanced MRI to longitudinally trace the spatial and temporal evolution of TAM infiltration during tumor progression. Our data demonstrated that TAMs facilitated the tumor neovascularization by incorporating into and/or coordinating the new vessel formation and TAM infiltration was accompanied by in situ tumor mass expansion, implying sequential TAM recruitment resulting in stepwise tumor outgrowth.

17:06 175. Factors Influencing in Vivo MR Imaging of Transplanted Pancreatic Islets Natalia Evgenov1, John Pratt1, Pamela Pantazopoulos1, Anna Moore1 1Massachusetts General Hospital, Charlestown, USA

A significant islet loss has been observed immediately after islet transplantation in diabetic patients. Previously we have showed that SPIO-labeled islets could be monitored by MRI. This study focused on both the effect of hyperglycemia and the effect of contaminating non-endocrine tissue on MRI imaging of islet grafts. We found that diabetic animals with transplanted islets showed significantly higher rate of islet death on in vivo MR images than their healthy counterparts. In contrast, transplantation of the islets contaminated with non-endocrine tissue did not have any significant influence on the imaging picture.

17:18 176. Tracking the Fate of Iron-Labeled Cells: Differentiation Between Live and Dead Cells Daniel Jirak1, Jan Kriz1, Ayman Oweida1, Jason Townsen2, Ann Chambers2, Brian Rutt1, Paula Foster1, 2 1Robarts Research Institute, London, Canada; 2University of Western Ontario, London, Canada

The use of iron oxides to label cells for their detection by MRI is quite widely used today in MR research. A question often posed about the areas of signal loss caused by iron labeled cells is whether they represent live or dead cells. It is assumed that if an iron-labeled cell dies it will be ‘cleared’ by the immune system and the area of signal loss will disappear. Here we present data from cellular MRI experiments in various models which suggests that whether or not the signal loss remains over time, when cells die, depends on the host tissue.

17:30 177. Self-Refocused Spatial-Spectral Pulse Pair for Positive Contrast Imaging of Cells Labeled with Superparamagnetic Iron-Oxide (SPIO) Nanoparticles Priti Balchandani1, John Pauly1, Philip Yang1, Mayumi Yamada1, Daniel Mark Spielman1 1Stanford University, Stanford, California , USA

We have developed a self-refocused spatial-spectral (SPSP) pulse pair to achieve slice-selective, frequency-selective, short-echo-time, spin-echo imaging. The self-refocused SPSP pulse pair is a phase-matched 90 SPSP pulse and 180 SPSP pulse combined, through a series of approximations, into a single pulse. The pulse pair is suitable for any application requiring spatial and spectral selectivity at short echo times. We utilized the pulse pair to perform slice-selective, positive-contrast imaging of superparamagnetic iron-oxide (SPIO) nanoparticle-labeled cells. Phantom and in vivo data demonstrate that the pulse pair is successful in creating positive-contrast images of SPIO-labeled cells for a selected slice.

17:42 178. Quantitative Tracking of Magnetically Labeled Breast Cancer Cells in Rat Brain with a Fast T2 Mapping Technique wei liu1, 2, Julien Senegas3, Ho-Taek Song2, 4, E Kay Jordan2, Hannes Dahnke3, Joseph A. Frank2 1Philips Research North America, Briarcliff Manor, New York, USA; 2National Institutes of Health, Bethesda, Maryland, USA; 3Philips Research Europe, Hamburg, Germany; 4College of Medicine, Yonsei University, Shinchon, Republic of Korea

Since intracellular SPIOs have much longer T2 compared to free SPIOs, measuring both T2 and T2* relaxation times will reduce the interference from free SPIOs for accurate quantification of SPIO labeled cells. T2 maps of the rat brain were acquired with a fast T2 mapping technique through undersampling and k-t reconstruction. Reduction of brain T2 after intracardiac injection of SPIO labeled breast cancer cells was characterized as 3-4% with both regular T2 mapping and fast T2 mapping. This mild reduction in T2 suggests that the significant alteration in brain T2* we observed previously was mainly induced by SPIOs labeled cells.

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17:54 179. MRI Detects in Vivo Migration of Rat's Bone Marrow Derived Mesechymal Stem Cells Towards Quinolinic Acid Lesion Noam Shemesh1, Ofer Sadan, 12, Daniel Offen, 12, Eldad Melamed, 12, Yoram Cohen1 1Tel Aviv University, Tel Aviv, Israel; 2Laboratory of Neurosciences, FMRC, Rabin Medical Center, Tel Aviv, Israel

Synopsis-The injection of Quinolinic Acid (QA) to the rat striatum is an important animal model of Huntington's disease (HD). Neurotrophic factors producing Mesenchymal stem cells (MSCs) are promising candidates for the treatment of CNS related diseases. The need to determine the implanted cells' viability has led us to test their ability to migrate from the deposition site towards the QA lesion. Our high-resolution 3D gradient echo images clearly show SPIO labeled cells that migrate and accumulate in the lesion. The MRI findings are correlated with immunohistochemistry, thus suggesting the viability of the cells up to 18 days post transplantation.

18:06 180. Magnetic Targeting of Stem Cells to a Site of Vascular Injury Using an MRI Contrast Agent Panagiotis Kyrtatos1, Pauliina Lehtolainen1, Manfred J. Ramirez, Anthony N. Price1, Thomas Poulianitis2, Quentin A. Pankhurst2, David G. Gadian, Mark F. Lythgoe1 1Institute of Child Health and Department of Medicine, University College London, London, UK; 2London Centre for Nanotechnology, London, UK

Cellular labelling with MRI contrast agents is becoming an established method of tracking cells in vivo, and it may also be possible to apply an external magnetic force on cells labelled with iron oxide. Endothelial progenitor cells (EPCs) are proliferative cells that can adopt an endothelial-like phenotype and are known to be involved in pathological and physiological processes such as tumour-induced and post-ischaemic neovascularisation. The long term aims of our study are to monitor the homing and retention of EPCs non-invasively using MRI and target them to the site of injury using an externally applied magnetic field, thus enhancing re-endothelialisation.

18:18 181. MRI Transverse Relaxation Rate Correlates with Number of Viral Particles Expressing H-Ferritin in the CNS Bistra Iordanova1, Clinton S. Robison1, William F. Goins2, Eric T. Ahrens1 1Carnegie Mellon University, Pittsburgh, Pennsylvania, USA; 2University of Pittsburgh, Pennsylvania, USA

Optimal use of transgenic animals and preclinical development of gene therapy requires methods for non-invasive visualization of gene expression. Our present work describes an indirect method of quantifying a gene expression using heavy-chain ferritin (H-Ft) MR reporter in the mouse the brain. We computed the 3D distribution of MR transverse relaxation rates in a mouse brain after transgene vector inoculation. We established that these relaxation rates correlate significantly to the number of inoculated infectious particles.

Cerebral Perfusion: Arterial Spin Labelling Room 701 A 16:30-18:30 Chairs: Susan T. Francis and Matthias Guenther

16:30 182. Mapping Middle Cerebral Artery Branch Territories with Vessel Encoded Pseudo-Continuous ASL: Sine/Cosine Tag Modulation and Data Clustering in Tagging Efficiency Space Eric C. Wong1, Akash Kansagra1 1UC San Diego, La Jolla, California , USA

In vessel encoded pseudo-continuous ASL, vessels flowing through the tagging plane are differentially tagged and encoded. Hadamard type encoding and a linear model are used to map perfusion territories. In this work, we depart from the linear model and exploit the continuous nature of the spatial modulation of tagging to identify multiple vascular territories with a small number of encoding steps. One method uses a sin/cos Fourier modulation technique, while the other uses data clustering in tagging efficiency space. Territories of at least three branches of the M2 Segment of the MCA can be mapped using these methods.

16:42 183. Superselective Pseudo-Continuous Arterial Spin Labeling Michael Helle1, 2, Matthias van Osch2, David Norris3, Karsten Alfke1, Olav Jansen1 1Christian-Albrechts-Universität, Kiel, Germany; 2Leiden University Medical Center, Leiden, Netherlands; 3FC Donders Centre for Cognitive Neuroimaging, Nijmegen, Netherlands

We introduce a modified tagging scheme based on pseudo-CASL that enables the labeling of single vessels. In this method the direction of additional transverse gradients is changed for every RF pulse in a random fashion. By adjusting the phase of the RF-pulses according to the applied extra gradients an efficient inversion results for the targeted vessel, whereas at other positions in the labeling plane phase variations avoid inversion. By increasing the strength of the added gradients, the labeling focus can be made more selective. Therefore this technique is capable of selectively labeling even small intracranial arteries.

16:54 184. Single Artery Selective Labeling Using Pseudo-Continuous Labeling Weiying Dai1, 2, Philip M. Robson1, 2, Ajit Shankaranarayanan3, David C. Alsop1, 2 1Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA; 2Harvard Medical School, Boston, Massachusetts, USA; 3GE Healthcare, Menlo Park, California , USA

A method for single artery selective labeling is presented in which a disc around the targeted vessel is labeled. Based on pseudo-continuous labeling, this method is achieved by rotating the directions of the added in-plane gradients. Numerical simulations of the strategy show good efficiency but poor suppression of labeling at large distances. Addition of amplitude modulation of the in-plane gradients results in good suppression of distant vessels. In-vivo results demonstrates highly selective labeling of individual vessels and a rapid falloff of the perfusion signal as a function of distance between the center of the labeling disc and the carotid artery, in agreement with simulation results.

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17:06 185. Selective Arterial Spin Labeling MRI Assessment of the Contribution of the External Carotid Artery to Brain Perfusion in Patients with Symptomatic Internal Carotid Artery Occlusion Jeroen Hendrikse1, Jeroen Van der Grond2, Peter Jan Van Laar3 1UMC Utrecht, Utrecht, Netherlands; 2UMC Leiden, Netherlands; 3UMC Utrecht, Netherlands

The aim of the present study was to investigate the qualitative and quantitative contribution of the ipsilateral external carotid artery (ECA) to cerebral perfusion in patients with symptomatic ICA occlusion. Grading of the qualitative contribution of the ECA was performed with intraarterial DSA and the quantitative contribution was assessed with selective ASL MRI. We found that in patients with internal carotid artery (ICA) occlusion focal brain regions strongly depend on the contribution to cerebral perfusion of the ECA ipsilateral to the side of the ICA occlusion, even in patients with a limited ECA collateral supply on intraarterial digital subtraction angiography.

17:18 186. How Long to Tag? Optimal Tag Duration for Arterial Spin Labeling at 1.5T, 3T, and 7T Wen-Ming Luh1, Eric C. Wong2, Peter A. Bandettini1 1National Institutes of Health, Bethesda, Maryland, USA; 2University of California, San Diego, La Jolla, California , USA

With the increase in field strength, higher SNR can be achieved for arterial spin labeling (ASL) because of increases in T1 values. The optimal duration of the tag will also increase with field strength; however, it becomes more difficult to achieve longer tag duration at higher field strength due to higher SAR for CASL and limited labeling coil size for PASL especially for whole brain coverage. In this paper, we estimated the optimal tag duration for 1.5T, 3T, and 7T for both techniques theoretically and verified the CASL results at 3T experimentally with pseudo-continuous ASL.

17:30 187. Can Arterial Spin Labeling Detect White Matter Perfusion? Wouter M. Teeuwisse1, Marianne AA van Walderveen1, Jeroen Hendrikse2, Mark A. van Buchem1, Jeroen van der Grond1, Matthias Johannes Paulus van Osch1 1Leiden University Medical Center, Leiden, Netherlands; 2University Medical Center Utrecht, Utrecht, Netherlands

Recently there has been much discussion about the feasibility to image white matter perfusion by arterial spin labeling. Recent advances in ASL methodology, like pseudo-continuous ASL, have further increased SNR. Furthermore, velocity selective ASL is less sensitive to delay. In this abstract we show that for both pseudo continuous ASL and velocity selective ASL the majority of white matter voxels show signal that is statistically significant larger than 0. Finally, we show in a patient with an AVM the ability of ASL to identify regions in the WM of disturbed hemodynamics as proven by DSC perfusion MRI.

17:42 188. Water Exchange Rates in Grey and White Matter Measured by Diffusion-Weighted Perfusion MRI Keith St. Lawrence1, 2, Sumei Wang3, Wen-Chau Wu3, Maria A. Fernandez-Seara3, Jiongjiong Wang3 1University of Western Ontario, London, Canada; 2Lawson Health Research Institute, London, Canada; 3University of Pennsylvania, Philadelphia, Pennsylvania, USA

The rate of water exchange (kw) across the blood-brain barrier was determined in grey and white matter regions using a diffusion-weighted arterial spin labelling (ASL) technique. Data were acquired at multiple post labelling delays to determine kw and the arterial transit time (ta) simultaneously. Averaged over five volunteers, kw was 181 and 262 min-1 in grey and white matter, respectively, and the corresponding ta values were 1.4 and 1.5 s. The kw in a developmental venous abnormality was shown to be lower than grey matter, which was attributed to the increased efflux of non-exchanged water into enlarged veins.

17:54 189. Rapid Blood T1 Calibration for Arterial Spin Labelling Marta Varela1, Jo V. Hajnal1, Esben Thade Petersen2, 3, Xavier Golay2, 4, David James Larkman1 1Robert Steiner MRI Unit, Hammersmith Hospital, Imperial College London, London, UK; 2National Neuroscience Institute, Singapore; 3Aarhus University Hospital, Aarhus, Denmark; 4Singapore Bioimaging Consortium, Singapore

The T1 of blood is a critical parameter in perfusion quantification using Arterial Spin Labelling. It is believed that T1blood may vary significantly within some patient and population groups, such as neonates, for whom ASL could constitute a valuable diagnostic tool. In this study, we introduce a method capable of rapidly measuring T1blood in vivo and present results for both healthy adults and neonates acquired in less than 3 minutes per subject at 3T. We also show that T1blood values obtained for adults are reproducible and in good agreement with existing literature.

18:06 190. A Comparative Study of Absolute Functional CBF Measurements in Normal Human Brain Using PASL MRI and [O-15]water PET Maolin Qiu1, R P. Maguire2, J Arora1, B Planeta-Wilson1, D Weinzimmer1, N Rajeevan1, R E. Carson1, R T. Constable1 1Yale University School of Medicine, New Haven, Connecticut, USA; 2Pfizer, Groton, Connecticut, USA

This study is to validate multiple-slice CBF measurements by PASL against those measured by PET and to test reproducibility of PASL CBF measurements. The resting and activated state CBF was measured by PASL and task-induced changes in CBF were estimated in functionally and anatomically defined cortical regions. These values were compared to those measured in PET experiments using the same tasks in the same the subject group. Using the PASL protocol described in this study, the global resting CBF measured by PET and MR agrees; however discrepancies in local CBF were found. Task-induced CBF changes measured by PASL are larger than those by PET and this was observed over all ROIs inspected, regardless of how they were defined; this difference may be attributed to differences in the hemodynamic response times of the two modalities. PASL showed good reproducibility in CBF measurements.

18:18 191. Is Arterial Spin Labeling Ready for Prime Time? Preliminary Results from the QUASAR Reproducibility Study Esben Thade Petersen1, Xavier Golay, 12, The QUASAR Reproducibility study 1National Neuroscience Institute, Singapore, Singapore; 2Singapore Bioimaging Consortium, Singapore, Singapore

Arterial Spin Labeling is often portrayed as a perfusion tool only working in dedicated settings. In this work, we evaluated the QUASAR implementation in a test-retest worldwide. 22 centers and 199 subjects participated in this trial where each subject was scanned twice two weeks apart. Operator-independent slice-planning was performed using automatic planning tools. The accuracy of the slice-planning as well as the overall and in-between site reproducibility of ASL was tested. Good slice repositioning was achieved and the test-retest showed reasonable reproducibility across sites, suggesting that ASL is ready for use within and across centers in future clinical multi-centre studies.

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Metabolic & Biochemical Tissue Characterization Using Non-Proton MR Room 701 B 16:30-18:30 Chairs: Pierre-Gilles Henry and Klaas Nicolay

16:30 192. Quantitative Cardiac 31P Spectroscopy at 3T: Practical Limitations and Solutions AbdElMonem M. El-Sharkawy1, 2, Michael Schär1, 2, Ronald Ouwerkerk1, Robert G. Weiss1, 3, Paul A. Bottomley1 1Johns Hopkins University, Baltimore, USA; 2Philips Medical Systems, Cleveland, USA; 3Johns Hopkins University School of Medicine, Baltimore, USA

Practical limits and solutions for accurate cardiac 31P MRS quantification at 3T are investigated. We find that long adiabatic BIR4 pulses used at 3T to overcome power constraints result in significant errors in steady-state magnetization in BIR4 protocols and T1 measured by the dual angle method. The errors are ameliorated with 90 adiabatic-half-passage (AHP) pulses. A custom coil and protocol for human cardiac 3T 31P MRS are used to measure the T1s of PCr and γ-ATP in the human heart with a new, efficient dual-TR approach that meets bandwidth and power requirements. The measurements are validated against conventional T1 methods.

16:42 193. Advances in the ERETIC Method for the Quantification of In-Vivo 1H and 31P Spectra Susanne Schweizer1, Nicola De Zanche1, Giel Mens2, Anke Henning1, Peter Boesiger1 1Institute for Biomedical Engineering, University and ETH Zürich, Zürich, Switzerland; 2Philips Medical Systems, Best, Netherlands

Absolute quantification is a desirable tool to determine metabolite changes. Calibration with ERETIC (Electric REference To access In vivo Concentrations) has proven to be an accurate method for the assessment of absolute concentration in spectra. In this work, we present a new implementation of ERETIC on a clinical scanner using a low-power transmit channel, thus permitting simultaneous use of proton decoupling and nuclear Overhauser enhancement with the high-power RF channel of the system during the acquisition of 31P or 13C spectra. Stability of the ERETIC signal is demonstrated. Also, ERETIC was for the first time applied to in-vivo 1H measurements.

16:54 194. Non-Parametric Analysis of Hyperpolarized Dynamic 13C Lactate Imaging in a Transgenic Mouse Model of Prostate Cancer< Janine M. Lupo1, Albert P. Chen1, Charles H. Cunningham2, Robert Bok1, John Kurhanewicz1, Daniel B. Vigneron1, Sarah J. Nelson1 1University of California, San Francisco, USA; 2Sunnybrook Health Sciences Centre, Toronto, Canada

While the main approach for pre-polarized 13C metabolic MR studies has utilized spectroscopic imaging techniques, acquiring high-resolution, full coverage dynamic lactate images to track the time course of 13C lactate in vivo after injection of pre-polarized 13C-pyruvate may be advantageous. This study demonstrated the feasibility of using 3D 13C dynamic lactate imaging to characterize lactate metabolism in vivo at high spatial and temporal resolution in a transgenic mouse model of prostate cancer. Non-parametric values obtained from the 13C lactate dynamic curves demonstrated differences within individual tumors as well as between tumors with different levels of disease progression.

17:06 195. Compressed Sensing for Resolution Enhancement of Hyperpolarized Carbon-13 Flyback 3D-MRSI Simon Hu1, 2, Michael Lustig3, Albert P. Chen1, Jason Crane1, Adam Kerr3, Douglas Kelley4, Ralph E. Hurd4, John Kurhanewicz1, 2, Sarah J. Nelson1, 2, John M. Pauly3, Daniel B. Vigneron1, 2 1University of California at San Francisco, San Francisco, California , USA; 2UCSF & UCB Joint Graduate Group in Bioengineering, San Francisco, California , USA; 3Stanford University, Stanford, California , USA; 4GE Healthcare, San Francisco, California , USA

Dynamic nuclear polarization has enabled rapid assessment of in vivo 13C metabolism at very high SNR. The high SNR from this hyperpolarization technique makes high-resolution 13C 3D-MRSI feasible. However, short T1’s limit the acquisition time and thus spatial resolution and coverage possible with conventional phase-encoding. In this project we developed compressed sensing (CS) methods to enhance spatial resolution without increasing acquisition time for a flyback 13C 3D-MRSI sequence. Following phantom testing, we applied this method in normal and prostate cancer rodent studies to achieve a factor-of-2 resolution enhancement in vivo with only a 20% decrease in SNR.

17:18 196. Combination of Datasets from [2-13C]Acetate and [1-13C]Glucose Experiments Improve Accuracy of Metabolic Rates Determination in Humans F Boumezbeur1, K Falk Petersen2, R A. de Graaf2, G W. Cline2, K L. Behar2, G I. Shulman3, D L. Rothman2, G F. Mason2 1Neurospin, I2BM, Gif-sur-Yvette, France; 2Yale University, School of Medicine, New Haven, Connecticut, USA; 3Howard Hughes Medical Institute, New Haven, Connecticut, USA

NMR spectroscopy (MRS) combined with 13C-labeled glucose allows the study of brain metabolism in vivo. To improve the precision of the quantitative determination of the rates of oxidative energy synthesis VTCAa, VTCAnand glutamatergic neurotransmission (VNT), we combined pairs of dynamic 13C MRS time courses on individual subjects who underwent both [1-13C]glucose and [2-13C]acetate infusions. Our results demonstrate that our new approach allows a more accurate quantification (~2 to 8 fold improvement of the precision of these rates. However, the rates obtained were consistent with previous studies using just one isotope, providing validation for experiments done with [1-13C]glucose.

17:30 197. Quantitative Tissue Oxygen Measurement in Multiple Organs Using 19F MRI Siyuan Liu1, Lisa J. Wilmes1, Vikram Kodibagkar2, Michael F. Wendland1, Nola Hylton1, Harriet W. Hopf3, Ralph P. Mason2, Mark D. Rollins1 1University of California, San Francisco, San Francisco, California , USA; 2University of Texas at Southwestern, Dallas, Texas, USA; 3University of Utah, Salt Lake City, Utah, USA

Critical patients need adequate oxygenation of vital organs. Measuring individual organ oxygen levels directly provides defined endpoints to titrate medical interventions. We evaluated the feasibility of 19F MRI for organ oxygen measurement and effects of hyperoxia on individual rat organs using a Varian 7T system, 19F/1H volume coil, and FREDOM sequence. The pO2 in all six organs examined, increased after changing from room air to 100% oxygen. The marked variability and different increases in organ pO2 show the diversities of oxygenation and potential benefit of regional measurements. This technique has potential to optimize patient resuscitation and guide cancer therapeutics.

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17:42 198. Improving the Resolution of SPRITE for in Vivo 23Na Imaging: A Comparison of Conical-SPRITE vs Sectorial-SPRITE Sandro Romanzetti1, Alexandre A. Khrapitchev2, Joachim Kaffanke1, Bruce J. Balcom2, Nadim Joni Shah1, 3 1Research Centre Juelich, Juelich, Germany; 2University of New Brunswick, Fredericton, Canada; 3University of Dortmund, Dortmund, Germany

In this work, images of the sodium distribution of an healthy brain were acquired using Conical- and Sectorial-SPRITE and compared in terms of their final resolutions. The Conical-SPRITE sequence provide images of good SNR but at a low-resolution which only allows one to delineate details such as CSF, and the eyes where the sodium signal is very strong. In contrast, Sectorial-SPRITE provides finer anatomical details of the brain that may be critical to monitor and diagnose pathologies leading to change of local Tissue Sodium Content.

17:54 199. Sodium MRI of the Human Brain Using Projection Acquisition in the Steady-State with Coherent Magnetization (Na-PACMAN) Robert Wayne Stobbe1, Christian Beaulieu1 1University of Alberta, Edmonton, Canada

The relaxation mechanism for sodium is different than for proton. The T2f component of transverse relaxation is related to macromolecular anisotropy and covers a very large relative range in the human brain. For this reason strongly T2f weighted sodium imaging may prove useful in the investigation of neurological disease, providing different contrast than proton or quantitative sodium concentration imaging. A new sodium imaging sequence (Na-PACMAN) is proposed for the generation of high quality, strongly T2f* weighted sodium images.

18:06 200. Quantifying Sodium in the Lumbar Spine in Vivo at 3T Matthew Fenty1, Chenyang Wang1, Walter RT Witschey II1, John Bruce Kneeland, M.D. 2, Ravinder Reddy, PhD1, Arijitt Borthakur PhD1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA; 2Pennsylvania Hospital, Philadelphia, Pennsylvania, USA

Degenerative Disc Disease (DDD) is a gradual deterioration of the disc between the vertebrae and may be a cause of lower back pain in adults. Sodium content correlates with proteoglycan content in cartilage tissue and therefore quantifying sodium via MRI may serve as an imaging biomarker for DDD. We demonstrate the feasibility of quantifying sodium concentrations in the intervertebral discs of the lumbar spine.

18:18 201. Detection of a New Pulmonary Gas-Exchange Component for Hyperpolarized Xenon-129 Yulin Chang1, Jaime F. Mata2, Jing Cai2, Talissa Altes1, 2, James R. Brookeman2, Klaus D. Hagspiel2, John P. Mugler III2, Kai Ruppert1, 2 1The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA; 2University of Virginia, Charlottesville, Virginia , USA

Over the years several hyperpolarized Xenon-129 spectroscopy studies revealed a puzzling and little explored discrepancy between the time constant for xenon entering the lung tissue (50-120 ms) and that for xenon returning to the alveoli through exchange (~10 ms in rabbits). By employing an uptake MRS pulse sequence with finely spaced delay times and comparing it to an exchange MRS sequence, we investigated in rabbits the origins of this apparent difference in time constants. Our results indicate that the tissue/plasma peak contains a component that is saturated in just a few milliseconds and clearly dominates the measured exchange time constant.

MR Physics and Techniques for Clinicians Hall F 16:30 - 18:30 Chairs: Frank R. Korosec and Joseph C. McGowan

Educational Objectives: Upon completion of this session, participants should be able to:

• Define and describe the fundamental principales of MR imaging, including the definition of spin magnetization, the Larmor relationship, relaxation phenomena, and the process of using the spin magnetization to produce an image;

• Explain imaging pulse sequences based upon spin and gradient echoes, including fast spin echo and echo planar techniques; • Design MR imaging protocols for diagnostic applications considering image contrast, spatial resolution, acquisition time, signal-to-noise ratio,

and artifacts; and • Describe the principles of parallel imaging, fat and water imaging, and diffusion imaging.

16:30 Spin Gymnastics Walter Kucharczyk and Donald B. Plewes 17:50 Hardware Mark D. Does

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Motion Artifact Correction Hall G 16:30-18:30 Chairs: Anja C. Brau and Donglai Huo

16:30 202. An Alternative Concept of Non-Sequence-Interfering Patient Respiration Monitoring Ingmar Graesslin1, Dennis Glaesel1, Peter Börnert1, Henry Stahl1, Peter Koken1, Kay Nehrke1, Henk Dingemans2, Giel Mens2, Jürgen Götze3, Paul Harvey2 1Philips Research Europe, Hamburg, Germany; 2Philips Medical Systems, Best, Netherlands; 3TU Dortmund, Dortmund, Germany

Patient motion is still challenging in MRI, especially in the abdominal region. The use of advanced motion artifact reduction techniques can improve diagnostic image quality. Motion sensing and correction approaches cope with this problem. However, e.g. navigators influence the steady state of SSFP sequences and are, therefore, not inherently compatible with this technique. This paper describes the application of respiratory motion detection from changes of the coil properties for steady state imaging, using a simple retrospective gating approach. Motion information is obtained in real-time. The method is compatible with almost any pulse sequence and no extra patient preparation is necessary.

16:42 203. Prospective Self-Gating for Simultaneous Compensation of Cardiac and Respiratory Motion Jelena Curcic1, Martin Buehrer1, Peter Boesiger1, Sebastian Kozerke1 1Institute for Biomedical Engineering, ETH Zurich, Zurich, Switzerland

A prospective self-gated approach for time-efficient free breathing cardiac imaging was successfully implemented and evaluated. Motion data needed for synchronization were accurately extracted in real-time from the repeatedly acquired k-space center thereby eliminating the need for external cardiac and respiratory signal detection. Using real-time filtering, cardiac and respiratory variations were separated and used for prospective triggering and gating. Image quality obtained with the proposed method was found to be comparable to the ECG triggered breathheld acquisitions as well as retrospective self-gating methods. The scan efficiency however could be significantly increased with respect to retrospective self-gating.

16:54 204. A New Respiratory Gating Technique for Whole Heart Cine MRI Sergio Andres Uribe1, Tarinee Tangcharoen1, Reza Razavi1, Tobias Schaeffter1 1Kings College London, London, UK

In this work we present a new respiratory gating technique for whole heart cine imaging. In this approach, we integrate the acquisition of an extra “slice navigator” within a b-SSFP sequence. The slice navigator in conjunction with a dedicated coil to read out the navigator signal makes the respiratory navigation more robust and sensitive to motion. A breathing signal was derived and used to gate the scan, which drastically reduced motion artifacts. The acquisition requires minimal planning and allows us to reformat the data in any view. The method represents a step forward for an easier cardiac MR examination.

17:06 205. Spherical Navigator Echoes Using GRAPPA for Rapid 3D Rigid-Body Motion Detection Junmin Liu1, Maria Drangova1 1Imaging Lab, Robarts Research Institute, Schulich School of Medicine, University of Western Ontario, London, Canada

The spherical navigator echo (SNAV) is ideal for tracking rigid body motion in all six degrees of freedom simultaneously. However, the relatively long time required to acquire a spherical navigator echo limits the utility of SNAV for short TR pulse sequence used in cardiac and functional MRI. A parallel imaging approach, based on the generalized auto calibrating partially parallel acquisition (GRAPPA) algorithm, was implemented to speed up SNAV acquisition. Using this SNAV-GRAPPA approach, hemispherical SNAV trajectories could be acquired as fast as 2.5 ms (at a bandwidth of 125kHz) with and acceleration factor R=4 while maintaining accuracy.

17:18 206. Real-Time Navigator Processing Using Kalman Filtering Pascal Spincemaille1, Thanh Dang Nguyen1, Martin Prince1, Yi Wang1 1Weill Medical College of Cornell University, New York, USA

Free breathing self-gated CINE acquisitions mostly rely on retrospective gating. A better suppression of motion artifacts and higher scanning efficiency can be achieved using prospective data acquisition gating. This abstract proposes the use of a commonly used real time filtering technique called the Kalman filter for processing noisy navigator data in real time. The Kalman filter adaptively estimates motion and suppresses measurement noise using Bayesian statistics and a motion model. Its ability to reduce noise and separate cardiac and respiratory components is studied in simulations, in-vivo data and in a free-breathing prospectively self-gated CINE SSFP acquisition of the heart.

17:30 207. Cardiac Gating Free of Interference with Electro-Magnetic Fields at 1.5T, 3.0T and 7.0T Tobias Frauenrath1, 2, Sebastian Kozerke2, Peter Boesiger2, Thoralf Niendorf1 1RWTH Aachen University, Aachen, Germany; 2University and ETH Zurich, Switzerland

In clinical MRI cardiac motion is commonly dealt with using ECG based synchronization. ECG is prone to interference with electromagnetic fields and to magneto-hydrodynamic effects, in particular at (ultra)high magnetic field strengths. For all these reasons, a non-invasive, fully MR compatible cardiac monitoring and gating approach which presents immunity to electro-magnetic field interferences is conceptually appealing. For this purpose a cardiac monitoring and gating device that employs acoustic signals was proposed. The chief aim of the current study is to explore the suitability of acoustic cardiac gating (ACG) for (ultra)high magnetic field strengths.

17:42 208. A Novel Technique Used to Detect Swallowing in Volume Selective TSE for Carotid Artery Wall Imaging Cheuk Fan Chan1, Raymond L. Hughes1, Peter Gatehouse1, Dudley J. Pennell2, David Firmin2 1Royal Brompton Hospital, London, UK; 2Royal Brompton Hospital, UK

Atherosclerotic carotid artery disease and the associated sequelae are the commonest cause of morbidity and mortality from cerebrovascular events in the Western world. Various MRI techniques have been established to image the vessel wall and to characterize plaque. Significant work to reduce scan times without compromising image quality has been undertaken. Artifacts associated with swallowing and heart rate variability lead to blurring and a reduction in vessel wall clarity. Using a novel anatomically positioned device linked with a k-space data rejection algorithm, we can demonstrate the improvement in the image quality.

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17:54 209. Prospective Motion Correction Via Real-Time Active Marker Tracking: An Image Quality Assessment Melvyn Boon King Ooi1, Sascha Krueger2, William Thomas1, S. V. Swaminathan3, Truman R. Brown1 1Columbia University, New York City, USA; 2Philips Research, Hamburg, Germany; 3Philips Medical Systems, Cleveland, Ohio, USA

Subject motion is a fundamental problem in MRI. We present here continuing work on prospective motion correction using micro RF-coils for fast motion tracking, followed by real-time scan geometry update. In particular, this work provides evidence, in quantitative metrics, that highlights the potential improvements in image quality allowed by this technique.

18:06 210. Velocity-Compensated DENSE MRI Xiaodong Zhong1, Florent Sureau1, Frederick H. Epstein1 1University of Virginia, Charlottesville, Virginia , USA

In DENSE, tissue displacement during the time between displacement encoding and the excitation RF pulse is intended to be measured. However, phase shifts unrelated to the desired displacement-induced shift can occur during the displacement-encoding period and the readout period due to tissue velocity. The purpose of this study was to investigate the errors caused by tissue velocity during these two periods on DENSE displacement estimates, and to show that these errors can be eliminated using velocity-compensated (first moment nulled) gradient waveforms.

18:18 211. Reduction of Flow Artifacts in Balanced SSFP Imaging Using S5FP J. Andrew Derbyshire1, Michael A. Guttman2, Robert J. Lederman2, Elliot R. McVeigh2 1National Institutes of Health, DHHS, Bethesda, Maryland, USA; 2NHLBI, National Institutes of Health, DHHS, Bethesda, Maryland, USA

Balanced SSFP imaging often suffers from severe artifacts due to (e.g. blood) spins that flow from one spectral band into an adjacent phase-opposed band. The flowing spins yield oscillating transient signals for the following several hundred TRs and hence imaging artifacts. The S5FP sequence provides balanced SSFP-like contrast for on-resonance spins, but destroys magnetization depending on the phase of the magnetization at TE = TR/2. Here we demonstrate that S5FP is an effective, robust and efficient method to suppress flow artifacts in balanced SSFP imaging.

Case-Based Teaching I: Evaluation of the Athlete with Hip or Groin Pain Room 717 A/B 16:30 - 18:30 Chairs: Timothy J. Mosher

Educational Objectives: Upon completion of this session, participants should be able to:

• Describe the range of causes for althetic pubalgia; • Explain the pathophysiology of sportsman hernia and femoral acetabular impingement; • Identify imaging findings that may lead to specific diagnoses in patients with pubalgia; • List the indications for hip and pubic symphysis MR Arthrography; and • Describe the role of 3.0T MRI in evaluation of the hip and pelvis.

16:30 MRI of Sportsman Hernia and Athletic Pubalgia Adam C. Zoga

17:30 MRI of Hip Pain in the Athlete Thaddeus Laird Study Group Hyperpolarized Media MR Room 718 A 18:30 - 20:30

Study Group Interventional MR Room 714 A/B 18:30 - 20:30

Study Group MR Engineering Room 718 B 18:30 - 20:30

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Study Group MR in Drug Research Room 716 A/B 18:30 - 20:30

Study Group Current Issues in Brain Function Room 701 B 18:30 - 20:30

18:30 Business Meeting 18:45 Scientific Meeting: Discussion Forum Accounting for Subject Differences in fMRI Analyses. Chair: Stephen M. Smith, D.Phil, Oxford University FMRIB Centre, Oxford, UK 18:45 Lead Discussant 1: Terry Oakes, Ph.D., University of Wisconsin, Madison, WI, USA 18:50 Lead Discussant 2: Richard B. Buxton, Ph.D., University of California San Diego, San Diego, CA, USA 18:55 Discussion What Can and Can’t Functional Spectroscopy Reveal About Neuronal Metabolism and Neurotransmission? Chair: Stephen R. Williams, D.Phil, University of Manchester, Manchester, UK 19:15 Lead Discussant 1: Rolf Gruetter, Ph.D., EPFL-SB-IPMC-LIFMET, Lausanne, Switzerland 19:20 Lead Discussant 2: Douglas Rothman, Ph.D., Yale University School of Medicine, New Haven, CT, USA 19:25 Discussion Topic 3: Will MR Deliver a Reliable Measure of OEF, CMRO2 and CMRO2 Change? Chair: Bruce Pike, Ph.D., Montreal Neurological Institute, Montréal, QC, Canada 19:45 Lead Discussant 1: Dmitriy Yablonskiy, Ph.D., Washington University School of Medicine, St. Louis, MO, USA 19:50 Lead Discussant 2: Wei Chen, Ph.D., University of Minnesota, Minneapolis, MN, USA 19:55 Discussion

Study Group MR Safety Room 713 A/B 18:30 - 20:30

The program for the ISMRM safety study group meeting will be dedicated to the results of a recent study performed in Europe by order of the European Commission to study the impact of the proposed European Directive for occupational exposure (2004/40/EC) on the usage of MRI in the clinical practice. The study is performed by the University of Zurich and the Imperial College in Londen on four clinical sites, and the results will be presented by the scientists from these institutes. The study includes the following aspects:

• Understanding of the existing and future medical procedures with MR scanners • Identification of worst case scenarios during usage of MR scanners • Systematic measurements of the EMF during these procedures • Calculation of the corresponding exposures in terms of current density and SAR

The findings of this study will be crucial for the reformulation of the directive as will be explained in the introduction of the program.

Study Group Susceptibility Weighted Imaging Room 717 A/B 18:30 - 20:30

Introduction, Mark Haacke, Ph.D., The MRI Institute for Biomedical Research, Detroit, MI, USA Technical Overview: What is susceptibility weighted imaging? What are the challenges open today? Jürgen Reichenbach, Ph.D.,University of Jena, Jena, Germany Clinical Overview: How is SWI useful clinically? What is needed to make it better? Some pediatric trauma examples. Karen Tong, M.D., Loma Linda University Medical Center, Loma Linda, CA, USA

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Technical Applications: fMRI with SWI Markus Barth, Ph.D., Radboud University, Nijmegen, The Netherlands Removing Phase Artifacts Jaladhar Neelavalli, B.E., Wayne State University, Detroit, MI, USA Animal Imaging Seong-Gi Kim, Ph.D., University of Pittsburgh, Pittsburgh, PA, USA Susceptibility Weighted Phase Imaging Alexander Rauscher, Ph.D., M.Sc., UBC MRI Research Centre, Vancouver, BC, Canada

Susceptibility Weighted Imaging (SWI) at Ultra High Magnetic Field Strengths Andreas Deistung, Dipl.Phys., Friedrich-Schiller University Jena, Jena, Germany Clinical Applications: Stroke Jonathan Grynspan (Canadian representative) Trauma and Tumors Vivek Sehgal (US representative), M.D., University of Chicago Medical Center, Chicago, IL, USA Venous Applications Masahiro Ida (Japanese representative), M.D., Tokyo Metropolitan Ebara Hospital, Toyko, Japan MS Applications Yulin Ge, M.D., NYU School of Medicine, New York, NY, USA SWI and Perfusion in Stroke Kohsuke Kudo, M.D., Ph.D., Hokkaido University Graduate School of Medicine, Hokkaido, Japan

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MORNING CATEGORICAL COURSE Safety Update Room 801 A/B 7:00 – 8:00 Organizer: Penny A. Gowland

Educational Objectives: Upon completion of this course, participants should be able to:

• List the main interactions between the static field and the sensory organs in humans; • List the main interactions between the static field and cells; • Explain the origins of the inhomogeneous temperature rise in the body due to exposure to the RF field from an MRI RF coil, and predict

situations likely to lead to an increased risk of RF burns; • Decide how to recommend whether it is safe to scan someone with an implant; • Identify the hazards associated with MR contrast agents, and contrast different types of agents in terms of the risk profiles; and; • Compare the regulatory position for MRI across the world.

07:00 Contrast Agents: Safety Profile Val M. Runge 07:30 Contrast Agents: Nephrogenic Systemic Fibrosis (NSF) Tim Leiner

MORNING CATEGORICAL COURSE Ultra-High Field MR in Humans Room 718 A 7:00 – 8:00 Chairs: Klaas Pruessmann and Lawrence L. Wald

Educational Objectives: Upon completion of this session, participants should be able to:

• Explain the importance of array technology for RF excitation and detection at ultra-high field, along with its basic modes of operation • Distinguish different types of BOLD contrast in ultra-high-field fMRI and describe corresponding pulse sequences; • Name the key problems and their current solutions in ultra-high-field MRS; • List promising applications of ultra-high-field MR in and outside the brain and name their remaining limitations.

07:00 Hardware for Parallel RF Transmission and Detection J. Thomas Vaughan 07:30 Multiple-Channel RF Pulses and SAR Control Peter Ullmann

MORNING CATEGORICAL COURSE Absolute Beginners’ Guide to Anatomical and Functional MRI of the Human Brain Room 718 B 7:00 – 8:00 Chairs: Alan Connelly and Chloe Hutton

Educational Objectives: Upon completion of this course, participants should be able to:

• Identify the neuroanatomical and neurophysiological parameters which are accessible to MR measurement; • Describe the underlying physics of MR neuroimaging techniques; • Describe the data acquisition and analysis techniques most commonly used for anatomical and functional MRI of the brain; and • Recognize the potential value of advances such as parallel imaging, fast imaging techniques and high magnetic field strengths for imaging the

brain. 07:00 Absolute Beginner’s Guide to Quantitative MRI Ralf Deichmann

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MORNING CATEGORICAL COURSE Clinical Science for Physicists and Engineers Room 714 A/B 7:00 – 8:00 Chairs: Vivian S. Lee, Tim Leiner, and Bachir Taouli

Educational Objectives: Upon completion of this course, participants should be able to:

• Identify basic anatomy and physiology of the central nervous system, kidney, liver, cardiac, vascular and musculoskeletal systems; • Describe the process and diagnosis of stroke and white matter formation and damage; • Explain kidney and liver anatomy and function, and how MRI can be used to evaluate these organs; • Discuss basic cardiac physiology and the consequences of coronary artery disease and heart failure; • Describe the process of bone and cartilage formation and degeneration; and • Appraise unmet clinical needs that could potentially be solved by physicists and engineers.

Brain: Anatomy, function, pathology, and challenges 07:00 Stroke: “A Brain Attack” Kei Yamada 07:30 Demyelination Massimo Filippi

MORNING CATEGORICAL COURSE Body MRI by the Experts II: Lung fMRI and Multi-Parametric Prostate MR Room 716 A/B 7:00 – 8:00 Chairs: Qun Chen, Clare Tempany, and Bernard E. Van Beers

Educational Objectives: Upon completion of this course, participants should be able to:

• Describe the impact of functional, quantitative and molecular MR in abdominal imaging; • Apply new body MR techniques in their practice; • Use multiparametric MRI for improved diagnosis of abdominal diseases; • Describe indications of functional and quantitative MRI in the assessment of liver, pancreas, bowel, and kidney diseases; • Design new female pelvic and prostate protocols, introducing these methods and compare them to more conventional approaches; and • Appraise the indications for anatomical and functional imaging of the breast and the lungs.

Lung Functional MRI, Qun Chen, Moderator 07:00 Clinical Perspective and Applications Hiroto Hatabu 07:30 MR Imaging of the Pulmonary Vasculature and Pulmonary Perfusion Edwin J. R. van Beek

MORNING CATEGORICAL COURSE Neuroimaging: What can clinicians learn from the animal model work? Room 701 A 7:00 – 8:00 Chairs: Pia C. Maly Sundgren and Annemie van der Linden

Educational Objectives: Upon completion of this course, participants should be able to:

• Describe the main MRI methods used in experimental studies to diagnose 1) Amyotrophic Lateral Sclerosis (ALS), 2) Stroke, and 3) Cerebral Amyloid Angiopathy (CAA), and the underlying rationale;

• Explain what is known about the underlying mechanism in ALS, stroke, and CAA and which type of MRI investigations could be used for (early) diagnosis of these diseases;

• List the main MRI methods used in the clinical setting to diagnose these diseases and the underlying principles behind them; and • Make the translate from what is – and can be – done in experimental studies on ALS, stroke, and CAA to what can be done clinically.

07:00 Focusing on Amyotrophic Lateral Sclerosis (ALS): Early Diagnosis through Experimental Work Greetje Vanhoutte

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07:25 Focus on Amyotrophic Lateral Sclerosis (ALS): Early Diagnosis in the Clinic Stefan Sunaert 07:50 Discussion

MORNING CATEGORICAL COURSE Clinical Application of Cardiovascular Imaging Room 701 B 7:00 – 8:00 Chairs: Georg Bongartz and Stefan G. Ruehm

Educational Objectives: Upon completion of this course, participants should be able to:

• Describe state-of-the-art MR techniques for cardiac imaging; • List the various approaches to the assessment of cardiac function, perfusion, and viability; • Interpret cardiac MRI in various pathologies; • Explain recent approaches to vessel wall and luminal vascular imaging; and • Describe typical problems in cardiovascular imaging, including artifacts.

Vascular Diseases 07:00 MRA of Thoracic and Abdominal Vessels James C. Carr 07:20 Peripheral MRA Stefan G. Ruehm 07:40 Whole-Heart Coronary MRA Hajime Sakuma

MORNING CATEGORICAL COURSE Cell Tracking Room 713 A/B 7:00 – 8:00 Chair: Jeff W. M. Bulte

Educational Objectives: Upon completion of this course, participants should be able to:

• List at least four methods to label cells; • List disease models in which MRI cell tracking is an important tool; • Recognize which clinical trials have been performed and what is likely needed for future FDA approval; and • Identify what role interventional radiologists will play in the future.

Cell Tracking: Labeling Methods and Techniques 07:00 Available Methods for Intracellular Labeling of Cells Hisataka Kobayashi

07:30 It’s Not All About Metals, You Know (19F is all you need) Tillman Cyrus MORNING CATEGORICAL COURSE Hyperpolarization: How to Obtain and Use a 100,000-Fold Increase in Polarization Room 715 A/B 7:00 – 8:00 Chairs: John P. Mugler, III, and Brian K. Rutt

Educational Objectives: Upon completion of this course, participants should be able to:

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• Describe “hyperpolarization,” that is, the physical process for generating nuclear polarization in certain gases or compounds that exceeds the thermal-equilibrium polarization achieved in typical MR scanners by several orders of magnitude;

• List the nuclei and compounds for which the hyperpolarized state has been achieved; • Identify the special requirements for MRI or MRS of hyperpolarized contrast media and describe pulse-sequence strategies that meet these

requirements; • List imaging and spectroscopy applications of hyperpolarized contrast media in animal models of disease; and • Implement hyperpolarized gas MRI in human pulmonary diseases for which it may improve detection and/or characterization compared to

current modalities.

Hyperpolarization Basics 07:00 Hyperpolarized Contrast Media: Overview of Principles & Applications Bastiaan Driehuys 07:30 Polarization Physics: Carbon-13 & Other Nuclei Jan H. Ardenkjaer-Larsen

MORNING CATEGORICAL COURSE Tissue Contrast in MSK MRI: From Physics to Physiology Room 717 A/B 7:00 – 8:00 Chairs: Bernard Dardzinski and Timothy J. Mosher

Educational Objectives: Upon completion of this course, participants should be able to:

• Describe the physical and molecular basis for T1, T2, T1p and MT contrast as they relate to collagen-rich tissues; • Identify the effects of tissue anisotropy on relaxation properties; • Apply understanding of mechanism of image contrast in musculoskeletal MRI to clinical and translational research applications; and • Describe the ultra-short TE and T1p techniques and potential clinical applications.

07:00 Relaxation Mechanisms in Collagen Rich Tissues Greg J. Stanisz 07:30 Pathogenesis of Tendon Degeneration and Aging Eugene G. McNally

PLENARY LECTURES: MR Elastography Hall F/G 08:15-09:30 Chairs: Kimberly K. Amrami and Vivian S. Lee

8:15 212. Over of MRE, Drive Technology, and Applications for Abdominal Imaging Richard L. Ehman1 1Mayo Clinic, Rochester, Minnesota, USA

MR Elastography (MRE) is an emerging diagnostic imaging technique for quantitatively assessing the mechanical properties of tissue. Human studies have demonstrated that it is feasible to quantitatively image the mechanical properties of skeletal muscle, brain, thyroid, kidney, liver, and skin. Results obtained by multiple investigators have provided strong evidence that MRE has excellent diagnostic accuracy for assessing hepatic fibrosis and is not affected by steatosis. This is the first established application of MRE, which is safer, more comfortable, and less expensive than liver biopsy and likely more accurate. MRE also shows promise for evaluating liver masses and other abdominal organs.

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8:40 213. Pulse sequences for MRE, MRE of brain and muscle Ingolf Sack1 1Charite, Berlin, Germany

There is currently no other technique than MRE which allows the non-invasive measurement of intracranial elasticity. First MRE studies in humans and animal models show the effect of Alzheimer’s disease, multiple sclerosis and aging on the biomechanical properties of the brain. MRE on skeletal muscle has been used to measure stiffness as a synonym of muscle function in various muscle-related diseases. New experiments demonstrate the feasibility of MRE to detect myocardial elasticity changes between diastole and systole, which are potentially related to intraventricular pressure changes. Recent success in cardiac and brain MRE was enabled by a tremendous acceleration of MRE using steady-state MRE sequences or spin echo EPI-MRE.

9:05 214. Inversion Algorithms for MRE, MRE of Breast Cancer Ralph Sinkus1 1Universite Denis Diderot, Paris, France

Imaging of mechanical shear waves via MR-Elastography allows the assessment of inherent viscoelastic tissue parameters. Reconstruction of mechanical parameters necessitates to properly taking into account all generated wave contributions (shear and compressional) when externally vibrating the object. MR-Elastography for breast cancer detection is performed after contrast enhanced MR-Mammography utilizing Gadolinium as contrast agent. The enhancement characteristics of benign and malignant tumors differ, which enables differential diagnosis. The diagnostic value of MRE as an adjunct to this established technique is presented and discussed, i.e. whether the addition of viscoelastic parameters improves the specificity for tumor characterization.

Mechanisms of BOLD Contrast Room 801 A/B 10:30-12:30 Chairs: Peter Jezzard and Kevin Murphy

10:30 215. Post-Stimulus FMRI Changes in Cerebral Blood Flow, Volume and Oxygenation Following Visual Stimulation and Breath-Hold Provide Evidence for the Hemodynamic Response Being Neurotransmitter-Mediated Manus Joseph Donahue1, 2, Robert D. Stevens1, Michiel de Boorder3, James J. Pekar1, 2, Peter van Zijl1, 2 1The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA; 2The Kennedy Krieger Institute, Baltimore, Maryland, USA; 3University Medical Center Utrecht, Utrecht, Netherlands

CMRO2, CBF and CBV all increase in gray matter parenchyma during visual stimulation, yet only CBF and CBV increase during breath-hold. Here, the relationship between neuronal activity and the hemodynamic response is investigated by performing BOLD fMRI (~CMRO2, CBF and CBV) concurrently with ASL fMRI (~CBF), and vascular-space-occupancy (VASO) fMRI at long repetition time (~CBV), during both visual stimulation and breath-hold. Results show that the BOLD post-stimulus undershoot is only present in the visual experiments, which suggests that this response is due to persisting CMRO2. These results provide additional evidence for an uncoupling of CMRO2 to CBF and CBV.

10:42 216. Origins of the BOLD Post-Stimulus Undershoot J. Jean Chen1, G. Bruce Pike1 1McGill University, Montreal, Canada

The BOLD post-stimulus undershoot has been attributed to either biomechanical venous ballooning or to sustained post-stimulus oxygen metabolism. Furthermore, a contribution from cerebral blood flow (CBF) undershoots has been demonstrated. We performed human in vivo fMRI measurements of the transient venous blood volume δ CBVv), δ CBF and δ BOLD under graded visual and sensorimotor stimulation using the QUIPSS II and VERVE (venous refocusing for volume estimation) techniques. We demonstrate a slow post-stimulus return of CBVv to baseline, which supports the existence of a passive “ballooning” effect. We also confirm the role of CBF undershoots in producing the BOLD undershoots.

10:54 217. The Post-Stimulation Undershoot in BOLD FMRI of Human Brain is Not Caused by Elevated Cerebral Blood Volume Jens Frahm1, Juergen Baudewig, Kai Kallenberg, Andreas Kastrup, Dietmar Merboldt1, Peter Dechent 1Biomedizinische NMR Forschungs GmbH am MPI fuer biophysikalische Chemie, Goettingen, Germany

The post-stimulation undershoot in BOLD fMRI, that is increased deoxyhemoglobin, has been suggested to originate from a delayed recovery of elevated CBV or CMRO2 to baseline. Here we performed bolus-tracking fMRI (Gd-DTPA, 8 subjects) at 3 T to evaluate the relative CBV (rCBV) during both visual stimulation and the post-stimulation undershoot. The results confirm a pronounced rCBV increase during stimulation (31.4 ± 8.6 %), but reveal no change in rCBV in the post-stimulation phase (0.7 ± 7.2 %). Assuming a rapid post-stimulation return of CBF to baseline this finding supports the idea of a prolonged elevation of oxidative metabolism.

11:06 218. Differentiating Sensitivity of Post-Stimulus Undershoot Under Diffusion Weighting: Implication of Signal Origins Todd B. Harshbarger1, Allen W. Song1 1Duke University, Durham, North Carolina, USA

The post-stimulus BOLD undershoot is generally observed in fMRI experiments. Recent studies have indicated the spatial localization of the undershoot may provide means for improved spatial localization to neuronal activities. In the present study, we applied diffusion weighting to eliminate intravascular spins of varying speeds in order to determine if the undershoot would be differentially affected based on the signal source. We show that areas in which the BOLD undershoot is reduced with increasing diffusion weighting are separable from areas which show no such effect. ADC values within affected areas are higher than unaffected regions, indicating their separate vascular origins.

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11:18 219. Intravascular vs. Extravascular Contributions to FMRI Signal Change for Visual Stimuli and Hypercapnia Hannah Devlin1, Egill Rostrup2, Daniel P. Bulte1, Karla Louise Miller1, Peter Jezzard1 1FMRIB Centre, Oxford, UK; 2Copenhagen University, Copenhagen, Denmark

Hypercapnic fMRI calibration has the potential to further the ultimate goal of quantitative fMRI. However, the technique makes the assumption that the spatial origins of the signal are equivalent for metabolic and hypercapnia-induced activation. We tested this assumption using a diffusion-weighted fMRI paradigm to investigate the relative intravascular (IV) and extravascular (EV) contributions to the BOLD signal for a visual stimulus and for hypercapnia. Our results imply that the relative intravascular and extravascular contributions may not be comparable for functional and hypercapnic stimuli suggesting that it may not be fully appropriate to calibrate functional BOLD data with hypercapnia.

11:30 220. Dissociation of CBF Responses Corresponding to Negative BOLD Activity Yi-Ching Lynn Ho1, 2, Esben Thade Petersen1, 2, Xavier Golay1, 3 1National Neuroscience Institute, Singapore, Singapore; 2University of Aarhus, Denmark; 3A*STAR, Singapore

The sustained negative BOLD signal could be a useful marker of neuronal inhibition/deactivation or simply a result of vascular draining. CBF activity could be differentiated between the two. A novel motor task elicited both positive (PBR) and negative (NBR) BOLD responses in the sensorimotor cortex. CBF changes were coupled with the contralateral PBR and ipsilateral NBR (thought to be due to neuronal inhibition). However, for the contralateral NBR, which surrounded the PBR in a pattern suggestive of the vascular steal effect, no significant CBF changes were seen.

11:42 221. Is the Negative BOLD Response a Gain Control Mechanism? Alex Robert Wade1 1SKERI, San Francisco, California , USA

We examined whether the magnitude of the negative BOLD response in visual cortex was a function of the ongoing neural activity in the suppressed region. We present data for the relationship between NBR magnitude and background contrast level in multiple retinotopic visual areas.

11:54 222. The Negative BOLD Effect in the Rodent Barrel Cortex Model: Investigation Using Multimodal Imaging and Electrophysiology Aneurin James Kennerley1, Luke Boorman1, David Johnston1, Ying Zheng1, Peter Redgrave1, John Edward Mayhew1, Jason Berwick1 1University of Sheffield, Sheffield, UK

Using fMRI at 7T we observed a prolonged negative BOLD signal surrounding a region in rat somatosensory cortex activated by electrical stimulation of the whiskers. The origin of the negative BOLD signal is not well understood. We therefore used intrinsic optical imaging and electrophysiology to investigate neurovascular coupling of this negative BOLD signal. Sensory-induced increases in neural activity were found to extend into the negative BOLD region. This suggests that the negative BOLD response does not reflect a corresponding decrease in underlying neural activity. Data were used to parameterize a forward biophysical model of neural activity.

12:06 223. A Temporal Comparison of Diffusion-Weighted FMRI, NIRS and BOLD Responses to Visual Stimuli in Adult Humans Satoru Kohno1, 2, Nobukatsu Sawamoto1, Shinichi Urayama1, Toshihiko Aso1, 3, Akitoshi Seiyama1, Denis Le Bihan3, Hidenao Fukuyama1 1Kyoto University Graduate School of Medicine, Kyoto, Japan; 2Shimadzu Corporation, Kyoto, Japan; 3NeuroSpin, Saclay, France

Functional response of diffusion-weighted magnetic resonance imaging (DfMRI) at high b-value precedes that of blood oxygenation level dependent (BOLD) fMRI by several seconds. The evidence suggests a direct link of DfMRI signal to neuronal activation, such as cell swelling. However, it was reported that total hemoglobin response measured with near-infrared spectroscopy (NIRS) also precedes BOLD response. Here, we compared temporal dynamics of DfMRI, NIRS and BOLD response, by conducting simultaneous acquisition of those signals during visual stimulation.

12:18 224. Caffeine's Effects on Neurovascular Coupling Yufen Chen1, 2, Todd B. Parrish1 1Northwestern University, Chicago, Illinois, USA

Caffeine is a widely consumed methylxanthine that binds nonspecifically to adenosine receptors leading to a reduction in resting blood flow while improving attention and cognitive function. In this study we investigate its effects on neurovascular coupling using the calibrated BOLD model. Subjects were scanned before and after an injection of 2.5mg/kg body weight of caffeine. Our results demonstrate that caffeine increases the CMRO2:CBF ratio in both motor and visual cortices.

It's All RF: Pulses, Trains, Sweeps & Feedback Room 718 A 10:30-12:30 Chairs: Charles H. Cunningham and Jürgen K. Hennig

10:30 225. Young Investigator Award Finalist: Slice-Selective Tunable-Flip AdiaBatic Low Peak-Power Excitation (STABLE) Pulse Priti Balchandani1, John Pauly1, Daniel Mark Spielman1 1Stanford University, Stanford, California , USA

Adiabatic pulses are useful in achieving uniform excitation profiles in the presence of B1 inhomogeneity. Gradient modulation techniques for slice-selective adiabatic excitation have been introduced; however, the resultant pulses exceed the RF amplifier limits for most human scanners. We present an alternative gradient modulated approach for pulse design that achieves adiabatic slice-selection with significantly lower RF peak power requirements. Our Slice-selective Tunable-flip AdiaBatic Low peak-power Excitation (STABLE) pulse consists of an oscillating gradient in conjunction with a BIR-4-like RF envelope that is sampled by many spatial subpulses. Phantom and in vivo results demonstrate the adiabaticity and selectivity of the STABLE pulse.

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10:50 226. Multiband Spectral-Spatial Design for High-Field and Hyperpolarized C-13 Applications Adam Bruce Kerr1, Peder E.Z. Larson2, Michael Lustig1, Charles H. Cunningham3, Albert P. Chen2, Daniel B. Vigneron2, John Mark Pauly1 1Stanford University, Stanford, California , USA; 2UCSF, San Francisco, California , USA; 3U Toronto, Toronto, Canada

A novel approach for multiband spectral-spatial design that iterates over feasible spectral sampling frequencies to determine the best design according to minimum-time, B1 or power criteria is presented. SLR RF design is combined with FIR filter design based on convex optimization and spectral factorization to minimize the energy in transition and don’t-care regions. Chemical-shift misregistration correction is also extended to support large-tip designs. Examples appropriate for spectroscopic imaging of C-13 pyruvate metabolites or C-13 lactate imaging at 3T are presented and validated.

11:02 227. A Spiral Spectral-Spatial RF Pulse with Rotated Variable Density K-Space Trajectory Weiran Deng1, Victor Andrew Stenger1 1University of Hawaii, Honolulu, Hawaii, USA

A spectral-spatial RF pulse with variable density spirals improve 2D spatial localization at the expense of increased aliasing outside the excitation field of view. By periodically rotating gradients, we found that slice aliasing can be significantly with in-vivo images.

11:14 228. SAR-Constrained Saturation Pulse Designs Based on B0 and B1 Maps Kyunghyun Sung1, Krishna S. Nayak1 1University of Southern California, Los Angeles, California , USA

Complete and uniform saturation are important for quantitative cardiac imaging. The saturation effectiveness is sensitive to the homogeneities of both the static (B0) and radiofrequency (B1) magnetic fields. The B0 and B1 variation across the left ventricle has been previously measured and a train of weighted hard pulses was chosen to optimally saturate over the expected region in B0-B1 space (minimizing the average residual Mz). In in-vivo studies, compared to BIR-4 and conventional pulse train saturation, the proposed saturation pulse showed the lowest residual Mz over the left ventricle with p < 0.001.

11:26 229. Correction of RF Pulse Distortions, with Application in Radial Imaging Using SWIFT Steen Moeller1, Curt Corum1, Djaudat Idiyatullin1, Ryan Chamberlein1, Michael Garwood1 1University of Minnesota, Minneapolis, Minnesota, USA

SWIFT (SWeep Imaging with Fourier Transform) is a new 3D radial sequence, utilizing frequency sweept pulses for simultaneous excitation and reception. Consistent Pertubations in the RF waveform different from the digital waveform creates bullseye artifact. A datadriven correction is proposed that effectively removes all of these pertubations. 3D Whole head SWIFT images is used to demonstrate the effectiveness of the proposed method.

11:38 230. The Virtual 180: Application to High Field Fast Spin Echo Imaging Robert Marc Lebel1, Alan H. Wilman1 1University of Alberta, Edmonton, Canada

We present a method for FSE imaging with drastically reduced RF power; applications include high field and high resolution studies. We demonstrate that the magnetization coherence typically associated with 180 refocusing pulses may be achieved, temporarily, without high flip angles pulses. By encoding this “virtual 180 echo” into the central region of k-space, we obtain a short echo train TRAPS sequence. This permits long echo spacings as required for high resolution imaging. In this work we describe how to form a virtual 180 and present example protocols and resulting images obtained at 4.7T.

11:50 231. Exponential Excitation Pulses for Improved Water Content Mapping in the Presence of Background Gradients Christine Preibisch1, Ralf Deichmann1 1University Frankfurt, Frankfurt, Germany

Introduction: Magnetic field gradients distort the exponential signal decay in multi-echo GE sequences, yielding erroneous values in water content maps based on extrapolation of the signal S(TE=0). Correct values can be achieved with exponentially shaped excitation pulses.Methods: Multi-echo GE images (phantom and volunteer) were acquired at 3T and simulations of saturation effects were performed for sinc and exponential excitation pulses.Results: Measurements and simulations show enhancement of S(TE=0) with increasing field gradient for sinc-shaped excitation pulses, but not for exponential pulses. Conclusion: Using exponential pulses increases the accuracy of water content mapping techniques in areas affected by field gradients.

12:02 232. Strongly Modulating Pulses: A New Method for Counteracting RF Inhomogeneity at High Fields Nicolas Boulant1, Denis Le Bihan2, Alexis Amadon2 1Siemens, St Denis, France; 2CEA-Saclay, Gif sur Yvette, France

A new RF pulse method for counteracting B1 inhomogeneity for 3D imaging is presented. The technique makes use of a 2D {B0,B1} histogram to generate rapidly pulses where the flip angle is made uniform over the volume of interest. Measurements performed at 3 T show a reduction by a factor up to 15 of the standard deviation of the sine of the flip angle, compared to when using a standard square pulse calibrated by the scanner. Calculations tend to show less energy demands than for adiabatic BIR4 pulses.

12:14 233. Accelerated Radiation-Damping for Increased Spin Equilibrium (ARISE): A New Method for Controlling the Recovery of Longitudinal Magnetization Susie Yi Huang1, 2, Thomas Witzel1, 2, Lawrence L. Wald1, 2 1Massachusetts General Hospital, Harvard Medical School, Charlestown, USA; 2Harvard-MIT Division of Health Sciences and Technology, Cambridge, USA

We introduce a method for accelerating the return of Mz to equilibrium that uses external feedback circuitry to strengthen the Radiation Damping (RD) field. This rotates the magnetization back to equilibrium faster than T1 relaxation. The method is characterized in phantom imaging and compared to numerical simulations. A 10ms feedback period in a crushed gradient echo sequence allowed >99% recovery of Mz in a long T1 phantom. Unlike SSFP, which is sensitive to off-resonance effects, the ARISE “flip-back” is self-generated and shows little off-resonance degradation, thereby offering a potentially useful building block for enhancing gradient echo sequences.

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Quantitative Imaging/Relaxometry Room 718 B 10:30-12:30 Chairs: N. Jon Shah and Graham A. Wright

10:30 234. Improved Accuracy of Variable Flip Angle T1 Measurements Using Optimal Radiofrequency and Gradient Spoiling Vasily L. Yarnykh1 1University of Washington, Seattle, Washington, USA

A variable flip angle (VFA) method is widely used for in vivo T1 mapping due to its time efficiency and easy 3D implementation with a large anatomical coverage. Practical implementations of VFA are typically based on a radiofrequency (RF) spoiled gradient echo (GRE) sequence. Incomplete spoiling was recently identified as a critical source of errors in the VFA method. Such errors are caused by the dependence of the optimal phase increment in the RF spoiling scheme on T2 of the object. This study demonstrates the way to overcome this problem by using a combination of RF and gradient spoiling and also presents a general methodology for theoretical analysis of spoiling phenomena.

10:42 235. An RF Pulse with Spoiled Sidebands Improves the Accuracy of T1 Measurement in DCE-MRI Dustin K. Ragan1, James Andrew Bankson1 1M. D. Anderson Cancer Center, Houston, Texas, USA

Quantitative studies using DCE-MRI depend upon accurate measurement of T1, however, accuracy is limited by the accuracy of the expected flip angle, which is in turn limited by the slice profile. Through simulation, we demonstrate the effects of slice profile errors on the measurement of quantitative pharmacokinetic parameters with several realistic and hypothetical pulses. We propose a novel pulse that generates a slice with suppressed sidelobes, minimizing their effects on T1 quantification. In phantom we show a marked improvement in the accuracy of T1 measurement with a two-point gradient echo technique compared to a conventional sinc pulse.

10:54 236. Robust Simultaneous δ R2 and δ R2* Estimation for Vessel Size Imaging Stefanie Winkelmann1, Julien Sénégas1, Janine Ring2, Thorsten Persigehl2, Christoph Bremer2, Hannes Dahnke1 1Philips Research Europe, Hamburg, Germany; 2University Hospital Münster, Münster, Germany

Recently it was shown that the mean vessel size of a tumor can be estimated from the local change of R2* and R2 induced by an iron-oxide based blood-pool agent. However, the fast wash-out characteristics of available contrast agents demand the rapid and simultaneous quantification of δ R2* and δ R2. We present a new MR sequence with a dedicated post-processing algorithm to achieve accurate δ R2* and δ R2 maps that are insensitive to large scale B0 and B1 field inhomogeneities as well as slice imperfections. The approach yielded very accurate and reproducible δ R2 and δ R2* maps in phantom and animal experiments.

11:06 237. Orientation Dependence of White Matter T2* Contrast at 7 T : A Direct Demonstration

Christopher John Wiggins1, Valdis Gudmundsdottir1, Denis Le Bihan1, Vincent Lebon1, Myriam Chaumeil1 1CEA/NeuroSpin, Saclay, France

By manipulating the position of the head of a macaque, it is demonstrated that some of the white matter T2* contrast seen in long TE images at 7T is strongly

dependent on the orientation of the tissue relative to the main magnetic field.

11:18 238. Modified PROPELLER Approach for T2-Mapping of the Abdomen Jie Deng1, 2, Andrew C. Larson1 1Northwestern University, Chicago, Illinois, USA

T2 mapping in the abdomen using SE or 2DFT-TSE sequences is challenging due to motion. The SE sequence requires long imaging times. TSE sequences can reduce imaging time but may be inaccurate due to stimulated echo accumulation. Furthermore, echoes not occurring at the effective TE may result in complex T2W signal contribution. Multi-shot TSE-based PROPELLER techniques have been shown to be less sensitive to motion artifacts. In this study we modified the PROPELLER sequence and acquisition approach to perform T2 mapping of the abdomen. We demonstrate that our modified PROPELLER approach permits robust acquisition of accurate, high-quality abdominal T2 maps.

11:30 239. Simultaneous T2- And T1-Mapping for Cardiac Applications Ulrike Blume1, Christian Stehning2, Stephen Sinclair1, Sergio Uribe1, Vicky Parish1, Tim Lockie1, Reza Razavi1, Tobias Schaeffter1 1King's College London, London, UK; 2Philips Research Europe, Hamburg, Germany

Cardiac MRI can depict areas of acute and chronic myocardial infarction by using different imaging sequences. In this work we propose free breathing navigator gated and ECG-triggered interleaved T2- and T1-mapping sequence which can be applied to acquire quantitative maps of heart in only one scan. First results are shown in phantoms and in vivo in 7 healthy volunteers and one patient with an acute myocardial infarction. The method has the potential to differentiate between acute and chronic MI by estimating the concentration of Gd from Δ R1 in the necrotic tissue and to assess edema from T2-maps.

11:42 240. Gleaning Multi-Component T1 and T2 Information from Steady-State Imaging Data Sean CL Deoni1, 2, Brian K. Rutt3, Tarunya Arun1, Carlo Pierpaoli4, Derek K. Jones5 1University of Oxford, Oxford, UK; 2Institute of Psychiatry, London, UK; 3Robarts Research Institute, London, Canada; 4National Institutes of Health, Bethesda, USA; 5Cardiff University Brain Research Imaging Centre, Cardiff, UK

Driven Equilibrium Single Pulse Observation of T1 and T2 (DESPOT1 and DESPOT2) are rapid, accurate and precise methods for quantifying the longitudinal and transverse relaxation times. An implicit assumption in the methods, however, is that of single-component relaxation which is not true in a variety of biological tissues, including human white and grey matter. In this work, we extend the DESPOT1 and DESPOT2 methods to include multi-component relaxation and demonstrate the ability to quantify component-specific T1, T2, volume fraction and mean residence time values over the whole-brain at high resolution.

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11:54 241. Volumetric Simultaneous T1, T2, T2* and Proton Density Mapping in One Minute Using Interleaved Inversion Recovery SSFP and Multi Gradient Echo Imaging Christian Stehning1, Stefanie Winkelmann1, Julien Sénégas1, Hannes Dahnke1 1Philips Research, Hamburg, Germany

A fast method for a simultaneous quantification of T1, T2, T2* and proton density is presented. The scan time is approximately one minute for a volumetric coverage of the brain. The sequence allows for rapid quantitative MRI, and represents a fast localizer scan for the generation of synthetic MR images with user-defined contrast.

12:06 242. Quantitative Diffusion, Perfusion and T2 Brain MRI of the α -Syntrophin Knockout Mouse in the Resting State Christian Brekken1, Asta Håberg1, Tina Pavlin1, Pål Erik Goa, 12, Atle Bjørnerud3, Olav Haraldseth1, 2, Ole Petter Ottersen4, Erlend A. Nagelhus4 1NTNU, Trondheim, Norway; 2St.Olavs Hospital HF, Trondheim, Norway; 3The National Hospital, Oslo, Norway; 4University of Oslo, Oslo, Norway

The predominate water protein.

12:18 243. Characterizing White Matter Damage in Rat Spinal Cord with Quantitative MRI and Histology Piotr Kozlowski1, Disha Raj1, Jie Liu2, Clarrie Lam2, Andrew Yung1, Wolfram Tetzlaff2 1UBC MRI Research Centre, Vancouver, Canada; 2ICORD, Vancouver, Canada

DTI and quantitative T2 MRI were used to characterize ex vivo the white matter damage 3 and 8 weeks following dorsal column transection (DC Tx) injury of the cervical rat spinal cord. MRI parameters were correlated with histology. Myelin water fraction (MWF) showed stronger correlation with myelin staining than transverse diffusivity. Both longitudinal diffusivity (Dlong) and fractional anisotropy correlated significantly with axonal count at 3 weeks post-injury, while only Dlong displayed significant correlation 8 weeks post-injury. This study demonstrates that quantitative MRI can accurately characterize white matter damage in DC Tx model of injury in rat spinal cord.

Metabolic Insights into Cancer in Cells, Tissues & Biofluids Room 714 A/B 10:30-12:30 Chairs: Nada M. S. Al-Saffar and Dmitri Artemov

10:30 244. Choline Kinase Silencing in Breast Cancer Cells Results in Compensatory Upregulation of Phosphatidylcholine-Specific Phospholipase C Kristine Glunde1, Noriko Mori1, Tomoyo Takagi1, Serena Cecchetti2, Carlo Ramoni2, Egidio Iorio2, Franca Podo2, Zaver M. Bhujwalla1 1The Johns Hopkins University School of Medicine, Baltimore, USA; 2Istituto Superiore di Sanità, Rome, Italy

Choline kinase (Chk) overexpression contributes to the elevated phosphocholine (PCho) and total choline (tCho) levels in breast cancers, detected by MRS. RNA interference-mediated Chk silencing decreased proliferation, increased differentiation, and increased the effect of 5-fluorouracil treatment in breast cancer cells, suggesting its use in anticancer therapy. Here we have shown that cellular PCho, which remained slightly elevated in breast cancer cells in spite of efficient Chk silencing, was possibly due to upregulation of phosphatidylcholine-specific phospholipase C protein expression in these cells. It may therefore be necessary to inhibit such compensatory enzymes along with Chk to achieve sufficient cell kill.

10:42 245. Phosphatidylcholine-Specific Phospholipase C Contributes to the Increase of Phosphocholine in Ovarian Cancer Cells Egidio Iorio1, Alessandro Ricci1, Maria Elena Pisanu1, Massimo di Vito1, Rossella Canese1, Delia Mezzanzanica2, Silvana Canevari2, Franca Podo1 1Istituto Superiore di Sanità, Roma, Italy; 2Istituto Nazionale Tumori, Milano, Italy

The activity of different enzymes contributing to the phosphatidylcholine (PC) cycle was investigated in human epithelial ovarian cancer cells, in order to identify the biochemical mechanisms responsible for increased phosphocholine (PCho) levels in ovary cancer. We here report that a strong (13- to 17-fold) activation of PC-specific phospholipase C (PC-plc) is associated in these cancer cells with the already known (13- to 20-fold) increase in choline kinase activity. These results suggest that PC-plc may represent a possible novel target of anticancer therapy.

10:54 246. Monitoring the Microenvironmental Effects on Choline Metabolism in Human Breast Cancer Cells Galit Eliyahu1, Talia Harris1, Nimrod Maril1, Raanan Margalit1, Hadassa Degani1 1Weizmann Institute of Science, Rehovot, Israel

Choline metabolites studied in breast cancer xenografts have indicated that microenvironmental conditions affect choline metabolism leading to changes in phosphocholine and glycerophosphocholine levels. Herein, real-time 31P MRS monitoring of choline metabolites in perfused breast cancer cells subjected to microenvironmental changes are presented. Acidosis induced a two fold decrease in phosphocholine level and hypoxia induced ~30% increase in its level. Extract studies indicated significant increase in glycerophosphocholine under acidosis and hypoxia. In addition to modulating choline metabolism by regulating gene expression processes during breast malignant transformation different, mechanisms of action are involved during acidosis and hypoxia as well.

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11:06 247. Elevated Choline Kinase Protein Expression and Activity Correlate with Increased MRS-Detected Phosphocholine Levels in Ovarian Carcinomas Egidio Iorio1, Kristine Glunde2, Tomoyo Takagi2, Alessandro Ricci1, Maria Elena Pisanu1, Silvana Canevari3, Zaver M. Bhujwalla2, Franca Podo1 1Istituto Superiore di Sanità, Rome, Italy; 2The Johns Hopkins University School of Medicine, Baltimore, USA; 3Fondazione IRCCS Istituto Nazionale dei Tumori, Milano, Italy

Human ovarian carcinoma cell lines exhibit increased phosphocholine (PCho) and total choline (tCho) concentrations compared to normal and immortalized ovarian epithelial cells, as detected by 1H MRS. Here we have shown for the first time that an MRS-detected increase in choline kinase (Chk) activity and intracellular PCho and tCho concentrations in ovarian cancers was, at least partially, due to elevated Chk protein expression levels. These findings indicate that ovarian carcinomas may be susceptible to Chk-targeted anticancer therapies, which can be evaluated and monitored by 1H MRS detection of tCho and PCho.

11:18 248. Phosphocholine Depletion is a Non-Invasive MRS Biomarker for PI3K Inhibition in Childhood High-Grade Glioma Nada S. Al-Saffar1, Lynley Marshall2, Laura Elizabeth Jackson1, Chris Jones2, Paul Workman3, Andrew Pearson2, Martin O. Leach1 1The Institute of Cancer Research and The Royal Marsden NHS Trust, Sutton, UK; 2The Institute of Cancer Reasearch, Sutton, UK; 3The Institute of Cancer Research, Sutton, UK

Phosphoinositide 3-kinases (PI3K) play an important role in the development of glioma, hence, PI3K inhibitors may be exceptionally useful in the treatment of these tumors. Using MRS we have investigated biomarker(s) for PI3K inhibition in pediatric high-grade glioma. Inhibition of PI3K signaling in the pediatric high-grade glioma cells SF188 with the novel class 1A PI3K inhibitor PI103 caused a decrease in PC levels detected by MRS. These results show that MRS could provide a biomarker for the non-invasive monitoring of response to novel PI3K-targeted therapeutic drugs in early stage clinical trials of these inhibitors in children with high-grade glioma.

11:30 249. Absence of Phosphatidylcholine (PC) in Bile of Cholestatic Patients Could Be a Potential Risk Factor for Cholangiocarcinoma: A 1H MRS Study Omkar B. Ijare1, Tedros Bezabeh1, Nils Albiin2, Urban Arnelo2, Bo Lindberg2, Ian C.P. Smith1 1National Research Council Institute for Biodiagnostics, Winnipeg, Canada; 2Karolinska Institutet, Huddinge, Stockholm, Sweden

The major lipid components of human bile are bile salts, cholesterol and phosphatidylcholine. Bile salts in bile have both protective and harmful effects on the biliary system. They form vesicles/mixed micelles with phospholipids and cholesterol in the normal physiology, and exercise harmful effects on cholangiocytes in the absence of phosphatidylcholine. 1H MR spectroscopy of human bile revealed the absence of phosphatidylcholine and elevated levels of glycerophosphocholine in some patients with chronic cholestasis. Phosphatidylcholine is an important phospholipid in bile, protecting cholangiocytes from toxic effects of bile salts. Bile devoid of phosphatidylcholine will be richer in the bile salts resulting in reduced micelle formation. The free bile salts in bile may bring about cholangiocellular damage, a possible risk factor for the development of cholangiocarcinoma.

11:42 250. Characterization of a Hepatoma Cell Line in a Novel 3D Bioreactor Flow System Using Hyperpolarized 13C MRS Kayvan R. Keshari1, John Kurhanewicz, Robert Bok, Albert Chen, David Wilson, Rex Jeffries, Mark Van-Criekge, Dan Vigneron, Jeffrey Macdonald 1University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, USA

Studies of hyperpolarized 13C labeled compounds, by way of the DNP method, have been used to investigate metabolic processes associated with the Warburg effect. The purpose of this study was to apply the DNP hyperpolarization method to a cancer cell line that will lead to potentially different metabolic cycles and behavior. For the first time, JM1 (rat hepatoma) cells were cultured in a 3D NMR compatible bioreactor and injected with hyperpolarized 13C1 pyruvate. These cells exhibited metabolism similar to previously described tumor models as well as intermediates associated with gluconeogenesis. This data suggests that is possible to visualize other metabolic processes.

11:54 251. Metabolic Activity of Diseased and Healthy Prostate Cells Investigated as Lactate Formation from Hyperpolarized 13C-Pyruvate Anna Gisselsson1, Mathilde Lerche1 1Imagnia AB, Malmö, Sweden

Anaerobic conversion of pyruvate to lactate is studied by using an in vitro model with four different prostate cell lines. The LDH isoform LDH5 has a high affinity for pyruvate and is highly up-regulated in prostatic carcinoma. The 13C-lactate formation is significantly higher in cancer cells compared to normal prostate cells after adding 13C-pyruvate. Total LDH activity in each respective cell line follows the same pattern as lactate formation. A high 13C-lactate formation after administration of hyperpolarized 13C-pyruvate to cancer cell suspensions correlates a new potential cancer diagnosis method, DNP-MR, to established diagnostic methods, using blood serum and biopsy analysis.

12:06 252. 13C Succinate Catabolism in Breast Cancer Cells is Sensitive to Extracellular PH and Glucose and Glutamine Levels Anthony Mancuso1, Stephen J. Kadlecek, Rahim R. Rizi, Craig B. Thompson 1University of Pennsylvania, Philadelphia, Pennsylvania, USA

Succinic acid metabolism by tumors is of interest because it can be hyperpolarized by the parahydrogen method. Transport of succinic acid across the cell membrane is mediated by dicarboxylic acid transporter proteins. Studies with Ehrlich Ascites Tumor Cells have demonstrated that succinate transport and oxidation is highly pH dependent. In addition, the flux of succinate into the TCA cycle will likely be strongly dependent on the availability of other substrates that can be used for cellular energy and biosynthesis. The goal of this work was to examine the effects of pH, glucose, and glutamine on succinate metabolism in a model breast cancer cell line. The results may be helpful for evaluating the suitability of hyperpolarized 13C succinic acid for studying breast tumors.

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12:18 253. Metabolic Biomarkers in Blood Plasma of Tumor Bearing Mice Detected by 1H NMR Spectra Radka Stoyanova1, István Pelczer2, Paul Hachem1, Qi Zhao3, Truman R. Brown3, Alan Pollack1 1Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA; 2Princeton University, Princeton, New Jersey, USA; 3Columbia University, New York, New York, USA

600 1H NMR spectra from plasma from xenograft mouse model of prostate cancer suggest correlation of the succinate amplitude and the presence of the orthotopically grown prostate tumors. There are variations in the lipid content that also seem to correlate with tumor burden and suggest systematic alteration of lipid metabolism. Orthotopic tumors were developed using several LNCaP cell lines. Pattern recognition techniques are applied to identify the spectral patterns related to tumorigenesis. CLINICAL CATEGORICAL COURSE The Pediatric Lower Extremity: The Unique Lesions of Childhood Room 716 A/B 10:30 - 12:30 Chairs: Clare Tempany and Bernard E. Van Beers

Educational Objectives: Upon completion of this course, participants should be able to:

• Recognize and identify the significance of lesions of the lower extremity that are unique to or more common in the developing skeleton; • Differentiate common normal variants of the developing skeleton from pathological processes; and • Protocol MRI for diseases of the pediatric lower extremity.

10:30 Pediatric Hip Karl Johnson 11:00 Pediatric Knee Andrea S. Doria 11:30 Bone Marrow and Inflammatory Lesions

R. Paul Guillerman 12:00 MSK Lesions Unique to the Developing Skeleton Jerry Dwek

AD: Of Mice & Men Room 701 A 10:30-12:30 Chairs: A. Alia and Youssef Zaim Wadghiri

10:30 254. Novel Method for in Vitro Evaluation of Amyloid Plaque Binding Contrast Agents in Alzheimer's Disease Malgorzata Marjanska1, Emily J. Gilles2, Ryan Chamberlain1, Denise A. Reyes2, Thomas M. Wengenack2, Michael Garwood1, Clifford R. Jack, Jr. 2, Joseph F. Poduslo2 1Center for Magnetic Resonance Research, Minneapolis, Minnesota, USA; 2Mayo Clinic College of Medicine, Rochester, Minnesota, USA

Currently, no in vivo diagnostic method exists for Alzheimer’s disease (AD). Molecular imaging may provide a method to not only visualize plaques but also diagnose AD at much earlier stage. One important problem in development of targeted contrast agents is an ability to assess binding properties of the contrast agent to the tissue or cellular target of interest. The technique described here is a novel in vitro assay to evaluate the effectiveness of contrast agent binding to the target of interest. This method involves gentle homogenization of unfixed AD mouse brain, incubation of the homogenate with a contrast agent, removal of unbound contrast agent by centrifugation and washing, and resuspension of the homogenate in gelatin in an MRI compatible glass tube.

10:42 255. Targeting Alzheimer's Plaques with Dysprosium Based Probes Youssef Zaim Wadghiri1, Moustafa Douadi1, Jing Yang1, Yeliz Utku2, Kent Kirshenbaum2, Thomas Wisniewski1 1NYU School of Medicine, New York, New York, USA; 2New York University, New York, New York, USA

MRI has been successfully used in transgenic mice for visualizing amyloid plaques, one of the hallmarks of Alzheimer’s Disease (AD). However, the plaque load remains underestimated using either endogenous iron detection or with the help of gadolinium-labeled targeted peptides, suggesting the need of increasing the sensitivity of the magnetic label. We demonstrate that dysprosium labeling of our amyloid probes is a great alternative to increasing the transverse relaxation rate hence increasing sensitivity without compromising the required physicochemical attributes critical for efficient plaque visualization.

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10:54 256. Micro MR Imaging of Beta-Amyloid Plaques and Co-Registration with Iron Deposition and Histological Analysis in Both Human Alzheimer’s Disease and APP/PS1 Transgenic Mice Mark D. Meadowcroft1, 2, James R. Connor1, Michael B. Smith2, Qing X. Yang1 1Penn State College of Medicine, Hershey, Pennsylvania, USA; 24. Novartis Institutes for BioMedical Research, Inc., Cambridge, Massachusetts, USA

Here we present data using a magnetic resonance microscopy (MRM) histological coil to view plaques in both human Alzheimer’s and APP/SP1 transgenic mice without contrast agents. The results indicate that iron in the plaques plays a role in observing A β plaque distribution in human Alzheimer’s samples with MRI. However, transgenic APP/PS1 mice show very little focal iron in plaques yet they are seen in the MR data. The data suggest that iron load alone does not account for the hypo-intensities that are observed in the T2* weighted images while plaque morphology and overall size of the plaques also do.

11:06 257. Correlation Between Neurochemical Changes and Development of Alzheimer’s Plaques with Age Monitored by in Vivo High Resolution Magnetic Resonance Microimaging and Spectroscopy Niels Braakman1, Jörg Matysik1, Huub JM De Groot1, Reinhard Schliebs2, A Alia1 1Leiden University, Leiden, Netherlands; 2University of Leipzig, Leipzig, Germany

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by the presence of β-amyloid plaques in the brain. Recent studies have shown that the neurochemical profile changes with the progression of AD. However, relationship between the development of β-amyloid plaques and changes in the metabolic profile with age has not yet been explored. In this study we optimized high resolution MRS and ìMRI sequences to explore the correlation between in vivo Alzheimer’s plaque development and neurochemical changes with age in the same transgenic mouse model of AD. Our results show clear relationship between increase in Alzheimer’s plaque load and changes in neurochemical composition of the brain with age.

11:18 258. Assessment of Cerebrovascular Reactivity as a Function of Age in a Transgenic Mouse Model of Alzheimer’s Disease Displaying Significant Vascular Pathology Using Acetazolamide Felicitas Laura Kranz1, 2, Thomas Mueggler1, 2, Marlen Knobloch2, Roger M. Nitsch2, Markus Rudin1, 2 1University and ETH Zurich, Zurich, Switzerland; 2University Zurich, Zurich, Switzerland

Cerebral amyloid angiopathy (CAA) and parenchymal amyloid plaques are the most specific pathological hallmarks of Alzheimer’s Disease. arcAβ mice develop a high vascular plaque load in an age dependent manner. Injection of acetazolamide leads to vasodilation and hence to CBV increase. Two parameters can be derived from dynamic CBV profiles: the rate of vasodilation (vascular reactivity) and the maximal CBV-value (vascular reserve capacity). Vascular reactivity was found to be impaired in arcAβ mice compared to age-controlled littermates, an effect which tended to increase with increasing age or CAA-load respectively. Maximal CBV-values tended to be lower in arcAβ compared to controls.

11:30 259. Cerebral Perfusion, Blood Volume, Vessel Size, and Vessel Density in the B6.PS2APP Mouse Model for Alzheimer's Disease Claudia Weidensteiner1, Friedrich Metzger1, Basil Kuennecke1, Markus von Kienlin1 1F. Hoffmann-La Roche Ltd, Basel, Switzerland

Functional and structural parameters of brain vasculature were studied with MRI in double-transgenic B6.PS2APP mice serving as an amyloid-bearing model of Alzheimer’s disease. Brain perfusion, blood volume, vessel size, and vessel density were assessed and compared to those in wild-type controls. Decreased perfusion was observed in B6.PS2APP mice in the dorsal part of the cortex at age 10, 12, and 17 months. This finding was corroborated by a decrease in blood volume detected in the same region in B6.PS2APP mice at age 17 months. No significant differences in vessel size or vessel density were observed.

11:42 260. Diffusion Tensor Imaging (DTI) Reveals Evolving White Matter Abnormalities in Patients with Alzheimer’s Disease Jiangyang Zhang1, Can Ceritoglu2, Kazi D. Akhter1, Michael I. Miller2, Marilyn Albert1, Peter C.M. van Zijl1, 3, Susumu Mori1, 3 1Johns Hopkins University School of Medicine, Baltimore, Maryland, USA; 2Johns Hopkins University, Baltimore, Maryland, USA; 3Kennedy Krieger Institute, Baltimore, Maryland, USA

We studied the evolution of diffusion tensor images for a population of Alzheimer’s disease (AD) patients (n=12) and normal elderly controls (n=18) over a period of one year. The multiple scan results were normalized to our single-subject DTI atlas using non-linear diffeomorphic mapping and cross-sectional and longitudinal analyses were performed simultaneously. These initial data suggest that there are evolving white matter abnormalities in a section of the corpus callosum in AD patients.

11:54 261. Biphasic Changes of Functional Hippocampal Connectivity Identifies AD Risks Zhilin Wu1, Yin Xu1, Gaohong Wu1, Piero Antuono1, Shi-Jiang Li1 1Medical College of Wisconsin, Milwaukee, Wisconsin, USA

The functional brain networks have been shown to be organized as anticorrelated networks with biphasic characteristics. In this study, we found that the hippocampal connectivity in the age-matched cognitively normal (CN) subjects consists of significant anticorrelated networks, which are similar to the default mode network. The Alzheimer’s disease (AD) subjects suffer a disrupted network in both positive and negative correlation to the hippocampus, while the amnestic mild cognitive impaired (aMCI) subjects mainly suffer the disrupted network in negative correlation to hippocampus. The hippocampal connectivity index (HCI) within the network can differentiate the three groups. These results suggest that the biphasic characteristics of the resting-state brain network are important in healthy CN subjects and are deteriorated along with AD progression.

12:06 262. Hippocampal Atrophy Patterns in Mild Cognitive Impairment and Alzheimer’s Disease Susanne G. Mueller1, Norbert Schuff, Sky Raptentsetsang, Kristine Yaffe, Catherine Madison, Bruce Miller, Michael Weiner 1Center for Imaging of Neurodegenerative Diseases, San Francisco, California , USA

Hippocampal subfields and total hippocampal volume were measured on high resolution MRIs in 47 controls, 14 MCI and 14 AD. AD had significantly smaller ERC, subiculum, CA1, CA1-2 transition and total hippocampal volumes and MCI had smaller CA1 and CA1-2 transition volumes than controls. This patterns is consistent with patterns of neuronal cell loss in histopathological studies. Discriminant analysis showed that CA1-2 was superior to total hippocampal volume for distinction between controls and subjects diagnosed with MCI. These findings suggest that hippocampal subfield volumetry might be a better measure for diagnosis of early AD than measurement of total hippocampal volume.

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12:18 263. The Dynamics of Olfactory FMRI BOLD Response Differentiate Early AD and MCI from Healthy Controls Lindsi Anne DeArment1, Paul J. Eslinger1, Erin K. Zimmerman1, Robert Grunfeld1, Jeffrey Vesek1, Mark D. Meadowcroft1, Michael B. Smith1, Jianli Wang1, James R. Connor1, Qing X. Yang1 1Penn State University College of Medicine, Hershey, Pennsylvania, USA

The goal of this study was to investigate the pathophysiology of olfactory brain structures in early Alzheimer’s disease (AD) and Mild Cognitive Impairment (MCI) with olfactory fMRI. The distinctive profiles of AD and MCI BOLD responses are uniquely different from one another and from age-matched control groups. These findings provide neurobiological validation of the behavioral olfactory deficits identified in AD and are promising since olfactory stimulation requires minimal active participation of subjects and allows a direct bioassay in the brain structures that are most vulnerable to early AD pathology.

CLINICAL CATEGORICAL COURSE CMR of Myocardial Infarction Room 701 B 10:30 - 12:30 Organizers:Christopher M. Kramer and Debiao Li

Educational Objectives: Upon completion of this course, participants should be able to:

• Recognize the utility of CMR in the measurement of infarct size and assessment of microvascular obstruction in acute myocardial infarction; • Compare T2-weighted CMR techniques with other imaging modalities for identifying area at risk in acute MI; • Evaluate the utility of CMR in the assessment of chronic LV remodeling; and • Describe the potential of CMR techniques for stem cell tracking.

10:30 Measurement of Infarct Size Robert M. Judd 10:50 Identification of Microvascular Obstruction Christopher M. Kramer 11:10 CMR Identify Area at Risk?

Andrew E, Arai 11:30 CMR and LV Remodeling Frederick H. Epstein 11:50 CMR and Stem Cell Tracking and Therapy Dara L. Kraitchman 12:10 Discussion

Diffusion MRI: Clinical Correlation & Prediction Room 713 A/B 10:30-12:30 Chairs: Alberto Bizzi and Roland G. Henry

10:30 264. Representation of the NIH Stroke Scale with Probabilistic Diffusion Weighted Imaging Lesion Atlas Kyle W. Singleton1, Timothy J. Schaewe2, W John Boscardin3, Marie Luby1, Steven Warach1, Chelsea S. Kidwell4, Jeffry R. Alger2 1National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland, USA; 2David Geffen School of Medicine at UCLA, Los Angeles, California , USA; 3School of Public Health, UCLA, Los Angeles, California , USA; 4Georgetown University, Washington, District Of Columbia, USA

The hypothesis is that probabilistic brain atlas techniques can be used to formulate statistically significant relationships between functional deficits as measured with the NIH Stroke Scale (NIHSS) and diffusion weighted imaging lesion characteristics in acute stroke patients. We have developed the first neuroanatomic atlas to combine acute infarct location and volume information with clinical deficit measured with the NIHSS. We show that lesion overlap measures derived from this atlas may be used to detect individual NIHSS item deficits with a high degree of accuracy.

10:42 265. Assessing Recovery in Comatose Cardiac Arrest Patients with Diffusion-Weighted MRI Ona Wu1, A Gregory Sorensen1, Thomas Benner1, Aneesh Singhal2, Karen L. Furie2, David M. Greer2 1Massachusetts General Hospital, Charlestown, Massachusetts, USA; 2Massachusetts General Hospital, Boston, Massachusetts, USA

Imaging data from comatose cardiac arrest patients who received diffusion-weighted MRI (N=72) were retrospectively analyzed to determine whether changes in the apparent diffusion coefficient (ADC) values can be used to predict good recovery. Recovery was based upon either eye opening or the six-month modified Rankin Scale (mRS) score. Patients with poor outcomes (mRS >3) or with no eye opening had significantly lower whole brain median ADC values compared to patients with good recovery or eye opening, respectively. Whole brain ADC measurements may play an important role in assessing recovery and patient management decisions in comatose cardiac arrest patients.

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10:54 266. DTI Derived Metrics Correlate with Immunohistochemistry Obtained Matrix Metalloproteinase (MMP-9) Expression in Cellular Fraction of Brain Tuberculoma Rakesh K. Gupta1, Mohd Haris1, Nuzhat Husain2, Sona Saksena1, Mazhar Husain2, Sanjay Behari1, Ram Kishore Singh Rathore3 1Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India; 2CSM Medical University, Lucknow, India; 3Indian Institute of Technology, Kanpur, India

Elevated Matrix Metalloproteinase (MMP-9) activity in cerebrospinal fluid from patients with central nervous system tuberculosis is associated with signs of local tissue destruction. Diffusion tensor imaging (DTI) derived indices are known to provide information about the tissue microstructural integrity in various disease conditions. In current study, MMP-9 in cellular fraction of brain tuberculoma showed significant correlation with DTI derived metrics suggesting that the DTI metrics may be used as surrogate marker of MMP-9 in vivo

11:06 267. Voxel-Based DTI Analysis of White Matter Alterations in Parkinson’s Disease Wang Zhan1, Gail A. Kang2, Graham A. Glass2, William J. Marks2, Yu Zhang1, Marzieh Nezamzadeh1, Andreas Ebel1, Xiaoping Zhu1, Rachel Millin1, Daniel McCoy1, Michael W. Weiner1, Norbert Schuff1 1University of California San Francisco, San Francisco, California , USA; 2VA Medical Center San Francisco, San Francisco, California , USA

Diffusion tensor imaging (DTI) at 4T was applied to analyze the alterations of white matter (WM) integrity on a voxel-wise basis in patients with Parkinson’s disease (PD). Tract-based spatial statistics (TBSS) technique was used to ensure robust co-registration of the DTI data and to perform non-parametric statistical testing. PD patients had reduced fractional anisotropy (FA) in regions known to be associated with PD pathology compared to age-matched control subjects. Furthermore, significant correlations were found between PD severity, as measured by the UPDRS motor scores, and the DTI indexes, supporting the hypothesis that movement impairment in PD is associated with regionally selective microscopic degeneration of WM.

11:18 268. Predictive Value of Diffusion Tensor Imaging (DTI) Metrics and in Vivo Proton MR Spectroscopy (PMRS) in the Differential Diagnosis of Cystic Intracranial Mass Lesions Rakesh Kumar Gupta1, Monika Agarwal1, Mazhar Husain2, Nuzhat Husain2, Kashi Nath Prasad1, Chandra Mohan Pandey1, Ram Kishore Singh Rathore3 1Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India; 2CSMM University, Lucknow, India; 3Indian Institute of Technology, Kanpur, India

In-vivo PMRS and DTI were performed in 53 patients of intracranial cystic mass lesions prospectively and were classified based on defined criteria of PMRS (a), mean diffusivity (MD, b), and fractional anisotropy (FA, c). Amongst 40 brain abscesses, 25 were confirmed on all three indices (a,b,c); 12 by two indices [(n=7; a,c) and (n=5; b,c)]; 3 by one index (c); while in cystic tumors (n=13), 10 were diagnosed on all three indices (a,b,c) and 3 by two indices (a,b). Findings indicate that FA is more sensitive (sensitivity, 1) while PMRS and MD are more specific (specificity, 1) for differentiating abscesses from tumors. We conclude that combining PMRS with DTI helps in better tissue characterization of cystic mass lesions.

11:30 269. Q-Space Diffusion Weighted Imaging (DWI) in the Spinal Cord: Comparison with Conventional DWI and Magnetization Transfer Imaging in Multiple Sclerosis Jonathan A.D. Farrell1, 2, Seth A. Smith1, 2, Eliza M. Gordon-Lipkin1, Daniel S. Reich1, Peter A. Calabresi1, Peter C. van Zijl1, 2 1Johns Hopkins University School of Medicine, Baltimore, USA; 2Kennedy Krieger Institute, Baltimore, USA

Water diffusion perpendicular to the spinal cord should be sensitive to loss of axonal and/or myelin barriers. Diffusion-weighted imaging (DWI) analyzed with the q-space technique provides a probability density function for diffusion. We demonstrate the feasibility of the technique in vivo in human cervical cord and, with respect to the detection of multiple sclerosis lesions, compare q-space contrasts to the perpendicular apparent diffusion constant (ADCp), and quantitative magnetization transfer (MT) measurements. Results from 8 controls and 4 patients show that, compared to ADCp, q-space DWI is more sensitive to abnormal diffusion and compares favorably with MT’s sensitivity to WM damage.

11:42 270. Quantitative Fiber Tracking After Perinatal Hypoxic-Ischemia and Neurodevelopmental Outcome at 2 Years Roel L.F. van der Palen1, Jan Buijs1, Anna Vilanova, F George Roos, Carola van Pul 1Maxima Medical Center, Veldhoven, Netherlands

Perinatal HI is an important cause of neuromotor disability in childhood. We used DTI and quantitative fibertracking to investigate the Corticospinal Tract in neonates with perinatal HI. Fiber volume of the CST at 0 and 3 months correlate with neuromotor outcome at 2 years. The normal outcome group has a higher volume at 0 and 3 months. In severe outcome, ADC and FA of the fibers are higher and lower at 0 and 3 months compared to a normal outcome, respectively. This suggests that in the severe group, edema and membrane disruption are more important contributing factors.

11:54 271. Apparent Diffusion Coefficient of the Superior Cerebellar Peduncle Differentiates Progressive Supranuclear Palsy from Parkinson’s Disease Caterina Tonon1, Raffaele Lodi1, David Neil Manners1, Giuseppe Nicoletti2, Francesca Condino2, Emil Malucelli1, Maurizio Morelli3, Fabiana Novellino3, Sandra Paglionico3, Pierluigi Lanza2, Demetrio Messina2, Paolo Barone4, Letterio Morgante5, Mario Zappia6, Aldo Quattrone2, Bruno Barbiroli1 1University of Bologna, Bologna, Italy; 2Institute of Neurological Sciences, Piano Lago di Mangone, Cosenza, Italy; 3University Magna Graecia, Catanzaro, Italy; 4University Federico II, Napoli, Italy; 5University of Messina, Messina, Italy; 6Università di Catania, Catania, Italy

The early diagnosis of progressive supranuclear palsy (PSP), a sporadic neurodegenerative disorder, may be challenging, because of clinical overlapping features with Parkinson’s disease (PD) and other parkinsonian syndromes. In our study an increase in mean superior cerebellar peduncle (SCP) ADC values in PSP but not in PD patients was detected, showing a diagnostic accuracy of 100% in differentiating between PSP and PD. The higher ADC values in SCP of PSP patients indicate microstructural changes reflecting the atrophy in this structure. These results provide an accurate MR diagnostic marker in differentiating parkinsonian syndromes.

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12:06 272. Evaluation of Whole Brain and Regional DTI Parameters on Diffuse Axonal Injury Patients in the Sub-Acute Stage Jiachen Zhuo1, Andrew Rosenkrantz1, Steven Roys1, Kathirkamanthan Shanmuganathan1, Stuart Mirvis1, Rao Gullapalli1 1University of Maryland School of Medicine, Baltimore, Maryland, USA

Diffuse axonal injury (DAI) represents the most common primary intra-axial form of traumatic brain injury (TBI). We evaluated 73 DAI patients at a sub-acute stage following injury using whole-brain (WB), whole-brain-white-matter (WBWM) and regional DTI parameters. Compared to normal controls, a widespread ADC increase throughout the brain was observed from both the global and regional measures. Globally FA also increased in patients while regional FA change only reached significance in the corpus callosum. Both WB and WBWM provided similar results. Among all parameters, peak ADC showed the strongest correlation with GCS suggesting it as a useful clinical marker for DAI.

12:18 273. Peripheral Versus Central White Matter Damage in Chronic Traumatic Brain Injury :a Quantitative Tractography Study Virginia Felicity Jane Newcombe1, Doris A. Chatfield1, Joanne G. Outtrim1, Jonathan P. Coles1, M G. Abate1, Sally G. Harding1, John D. Pickard1, Peter J. Huchinson1, T Adrian Carpenter1, Guy B. Williams1, David K. Menon1 1Cambridge University, Cambridge, UK

Diffuse axonal injury is classically observed in the more central white matter (WM) areas. However, microscopic lesions may also occur peripherally at the gray/white matter junction and in the subcortical white matter. This study used diffusion tensor imaging and quantitative tractography to assess the extent of central and peripheral white matter damage in patients with chronic traumatic brain injury which may explain some of the morbidity seen after injury. The damage seen appears to be more dominant in the central than peripheral white matter.

Developments in MR-Guided Interventions Room 715 A/B 10:30-12:30 Chairs: David M. Saloner and Tobias Schaeffter

10:30 274. Highly-Loaded Holmium Microspheres for Test Dose Detection and Biodistribution Prediction in Internal Radiation Therapy of Liver Malignancies Peter Roland Seevinck1, Wouter Bult1, J Frank Nijsen1, Maarten A. Vente1, Remmert R. Roos1, Alfred D. van het Schip1, Chris J.G. Bakker1 1University Medical Center, Utrecht, Netherlands

Transcatheter arterial embolization with radioactive holmium-166 microspheres (HoMS) is a promising treatment option for liver cancer, in which accurate assessment of the radionuclide biodistribution is of major importance for treatment planning and dosimetry. Therefore, highly-loaded HoMS have been designed exhibiting high sensitivity on MRI. In this study, we demonstrated test dose detection, biodistribution prediction and the feasibility to quantify local HoMS dose in an ex vivo rabbit liver. Highly-loaded HoMS might allow the detection of extra-hepatic shunting, accurate treatment planning and dosimetry, opening the way to perform fully MR-guided transcatheter hepatic arterial embolization radiation therapy in the near future.

10:42 275. MR Guided Islet Cell Transplantation David Arthur Woodrum1, Thomas Link2, Wesley D. Gilson2, 3, Brad P. Barnett2, Li Pan2, 3, Christine H. Lorenz2, 3, Di Qian2, Dara L. Kraitchman2, Jeff WM Bulte2, Aravind Arepally2 1Mayo Clinic, Rochester, Minnesota, USA; 2Johns Hopkins University School of Medicine, Baltimore, Maryland, USA; 3Siemens Corporate Research, Baltimore, Maryland, USA

Magnetic resonance (MR)-trackable magnetocapsules (MCs) were created to simultaneously immunoprotect pancreatic beta cells and non-invasively monitor portal vein delivery and engraftment using MR imaging (MRI). The purpose was to demonstrate the feasibility of MRI guided delivery and monitoring of islet cell transplantation with MCs containing human islets in a swine model. The magnetocapsules were clearly visualized as magnetic susceptibility-induced hypointensities within entire liver and were trackable with standard MRI scanners. Follow-up MR imaging at 4 and 8 weeks post-transplantation demonstrated no changes in MR appearance of capsules with measurable Human C-peptide confirming the functional status of the transplant graft.

10:54 276. X-Ray Fusion with MRI for Delivery of Encapsulated Stem Cell Therapeutics Wesley D. Gilson1, 2, Merdim Sonmez1, 3, Cengizhan Ozturk3, David Woodrum4, Dorota Kedziorek2, Di Qian2, Bradley Barnett2, Jeff WM Bulte2, Christine H. Lorenz1, 2, Elliot R. McVeigh2, Robert J. Lederman3, Aravind Arepally2, Dara L. Kraitchman2 1Siemens Corporate Research, Baltimore, Maryland, USA; 2Johns Hopkins University, Baltimore, Maryland, USA; 3National Institutes of Health, Bethesda, Maryland, USA; 4Mayo Clinic, Rochester, Minnesota, USA

The aim of this study was to investigate the use X-ray and MR image fusion for guiding delivery of stem cells contained in X-ray visible microcapsules (XCaps). Phantom studies were performed to evaluate targeting capabilities. For in vivo studies, cine and contrast-enhanced viability MR images were acquired in a canine with a myocardial infarction. Myocardium and infarct segmentation was performed and fused with live X-ray fluoroscopic images to guide delivery of 15 XCaps injections to peri-infarcted and infarcted tissue. XCaps were readily visible under X-ray, and delivery was possible using conventional endovascular devices with conventional physiological monitoring.

11:06 277. Monitoring Liver Tumor Embolization in VX2 Rabbits: Four-Dimensional Transcatheter Intraarterial Perfusion (TRIP) MR Imaging Dingxin Wang1, Sumeet Virmani1, Gayle Woloschak1, Tatjana Paunesku1, Riad Salem1, Reed Omary1, Andrew Larson1 1Northwestern University, Chicago, Illinois, USA

In this study, we present a quantitative four-dimensional TRIP-MRI technique (serial iterative 3D volumetric perfusion imaging) with rigorous B1+ field calibration and dynamic tissue R1 measurement for intra-procedural assessment of liver tumor perfusion reductions during transcatheter arterial embolization (TAE).

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11:18 278. Imaging of Anatomical Structure and Blood Vessels in Porcine Gastric Wall by MR Endoscope Yuichiro Matsuoka1, Yoshinori Morita2, Hiromu Kutsumi2, Hiroaki Miyasho3, Makiya Matsumoto4, Takayuki Miyamoto5, Etsuko Kumamoto4, Takeshi Azuma2, Kagayaki Kuroda1 1Institute of Biomedical Research and Innovation, Kobe, Japan; 2Kobe University School of Medicine, Kobe, Japan; 3Olympus Medical Systems Corp., Hachioji, Japan; 4Kobe University, Kobe, Japan; 5Intervention Technical Center Co., Ltd., Kobe, Japan

The final goal of this study is to establish MR endoscope system, which can implement MR imaging and endoscopy simultaneously and provide MR images superimposed on scope view as navigation. In this paper, the capability to depict anatomical structure and blood vessel in gastric wall in vivo experiment was examined with the developed intracavitary RF coil for 1.5-T MRI. Four or five layers in gastric wall and vascularity in submucosa and muscularis were depicted. The usefulness and ability of MR imaging to support diagnostic endoscopy and also ESD was demonstrated.

11:30 279. MRI Endoscopy at 3T Shashank Sathyanarayana1, Michael Schar2, 3, Paul A. Bottomley3 1Johns Hopkins University, Baltimore, USA; 2Philips Medical Systems, USA; 3Johns Hopkins University, USA

RF transmission and reception by modified miniature internal probes can inherently localize the MRI signal to the probe-head, creating a true MRI endoscope. The method is tested in a kiwifruit and in an intact porcine aorta at 3T with in-plane resolution down to 100µm and 1.5mm “slice”-width. A local peak SAR of 0.5W/kg associated with an 0.1ºC temperature rise over ten minutes is seen during heat-testing of the endoscope in a gel phantom. MRI endoscopy can be used for efficient, real-time, high resolution internal imaging with intrinsically lower SAR than encountered with conventional body-coil excitation at 3T.

11:42 280. A 5 Degree of Freedom Haptic System for Transrectal Prostate Biopsy and Tissue Palpation with MR Image Guidance Zion Tsz Ho Tse1, Haytham Elhawary1, Marc Rea1, 2, Aleksandar Zivanovic1, Collin Besant1, D McRobbie2, Ian Young1, N de Souze3, Brian L. Davies1, Michael Lamperth1 1Imperial College London, London, UK; 2Charing Cross Hospital, London, UK; 3Royal Marsden NHS Foundation Trust, Surrey, UK

An MR compatible 5 DOF haptic system has been developed for transrectal prostate biopsy and tissue palpation diagnosis, incorporating force feedback and replication to the operator at a master console during needle insertion. Tissue stiffness can be measured along the needle trajectory, which can aid diagnosis of suspected cancerous tissue. An in vitro experiment is shown to distinguish a phantom tumour and a normal lamb liver based on the force profile captured during needle insertion. Fiducial tracking technology has been integrated into the system for real-time tracking of the biopsy needle, probe and slice orientation with accuracy of 0.2mm.

11:54 281. MRI Compatible Robotic System with Haptic Feedback for RF Ablation/Biopsy Under Continuous MRI Kevin Lister1, Kokes Rebecca1, Bao Zhang2, Rao P. Gullapalli2, Jaydev P. Desai1 1University of Maryland, College Park, Maryland, USA; 2University of Maryland School of Medicine, Baltimore, Maryland, USA

Initial results from the design and operation of a prototype MRI-compatible single degree of freedom robot for automated RFA/biopsy probe advancement with haptic feedback, along with a series of experiments proving MRI-compatibility and functionality of the device are presented. Phantom studies show a strong correlation between the force feedback signals from a biopsy probe and the tissue interfaces within the phantom which was confirmed using MRI guided imaging. The work presented in this paper is the first step toward the development of a robotic system with multiple degrees of freedom for RFA/biopsy of tumors under continuous MR imaging.

12:06 282. MRI-Compatible Haptics: Feasibility of Using Optical Fiber Bragg Grating Strain-Sensors to Detect Deflection of Needles in an MRI Environment Yong-Lae Park1, Santhi Elayaperumal1, Bruce Lewis Daniel1, Elena Kaye1, Kim Butts Pauly1, Richard J. Black2, Mark R. Cutkosky1 1Stanford University, Stanford, California , USA; 2Intelligent Fiber Optic Systems Corporation, Santa Clara, California , USA

Bragg grating sensors in an optical fiber can provide information about the forces and bending geometry of catheters, needles, and other devices to reach targets in MRI guided interventions. We present the results of early experiments with an instrumented biopsy needle, which show high force sensitivity, immunity to the electromagnetic field and no imaging artifacts.

12:18 283. 2D-Real-Time MR Imaging and Simultaneous X-Ray-Like Volume Visualization of Devices Steffen Weiss1, Sascha Krueger1, Oliver Lips1 1Philips Research Europe, Hamburg, Germany

MR real-time slices cannot display out-of-slice sections of devices. Here, a method for real-time imaging of a thin slice and simultaneous visualization or tracking of devices in a volume is presented. Volume visibility of the device is achieved by the transmission of hard pulses with the device. Signal reception with the active device during real-time 2D imaging is used to reconstruct the projection of the device onto the imaging slice and to display it as a color overlay. The method combines high contrast MR imaging of the anatomy in a thin slice with continuous volume visibility of devices as appreciated in X-ray fluoroscopy.

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Tissue Characterization Using MR Microscopy Room 717 A/B 10:30-12:30 Chairs: Cornelius J. Faber and Daniel H. Turnbull

10:30 284. New Techniques for 3D, High-Resolution, Whole Brain Mapping of Murine Vasculature Arvind P. Pathak1, Melina Jones1, Jiangyang Zhang1 1The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA

Knowledge of the 3D architecture of blood vessels is crucial because neuropathologies ranging from alzheimers disease to brain tumors involve anomalous blood vessels, and development of transgenic mouse models of disease has created a need to characterize the cerebral vasculature. While histological techniques such as optical microscopy and corrosion casting are excellent for imaging microvasculature at submicron resolutions, they suffer from limited coverage, and 3D blood vessel geometry once destroyed by sectioning requires complex reconstruction. Here we describe two novel methods for “whole brain” mapping of murine vasculature using magnetic resonance microscopy to obtain exquisite images with different “physiological stains”.

10:42 285. Empirical Estimation of Intra-Cellular Volume Fraction in Mouse Spinal Cord with Q-Space Diffusion MRI Henry H. Ong1, Felix W. Wehrli1 1University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA

Knowledge of white matter intra- and extra-cellular volume fraction (ICF and ECF) would provide important insight into injury and pathology. Current diffusion MRI techniques measure ICF by numerically solving a difficult ill-posed Laplace inversion of the signal decay or fitting the decay to a model, which requires assumptions of the system. Recently, an experiment has been proposed to empirically measure ICF based on the different dependences on diffusion gradient length of restricted and Gaussian diffusion of the ICF and ECF, respectively. Here, we apply this technique to quantify ICF of healthy mouse spinal cords and compare the data to histology.

10:54 286. Detection of Embryonic Heart Motion in the Mouse Using Self-Gated MRI Brian J. Nieman1, 2, Daniel H. Turnbull1 1New York University School of Medicine, New York, USA

Self-gated imaging methods permit collection of motion sensitive data for use in artifact correction or gating without the need to interrupt image acquisition for additional radiofrequency or gradient events. These methods are attractive for implementation in studies involving mice, due to their small size, or wherever external measures are cumbersome or unavailable. In this abstract, we explored the possibility that a self-gated method would permit detection of embryonic cardiac events in utero and show calculated physiological traces correlate with the heart cycle, suggesting that cine cardiac MRI of the mouse in utero should be possible.

11:06 287. Determining Cellular Microstructure of Isolated Rat Hearts Using Correlated Time-Dependent Diffusion and T2 Relaxation Measurements Tina Pavlin1, Morten Bruvold1, Per Jynge1, John Georg Seland1 1Norwegian University of Science and Technology, Trondheim, Norway

The aim of this work was to study compartmentation and water diffusivity in isolated rat hearts by correlating time-dependent diffusion coefficient and T2 relaxation constant. Compartmental diffusivity enabled us to obtain structural information about the intra- and extra-cellular compartments in rat myocardium. Using a short-time diffusion model and assuming a cylindrical geometry of myocardial cells, we estimated the diameter of the cells to be 35 µm, and the inter-cell distance to be 20 µm.

11:18 288. Diagnostic Impact of T2* MRI Imaging for Improved Ex Vivo Classification of Complicated Plaques Timo Spehl1, Dominik Paul1, Michael Markl1, Dominik von Elverfeldt1, Heike Göbel1, Alex Frydrychowicz1, Andreas Hetzel1, Cornelius Weiller1, Joachim Schöllhorn1, Jürgen Hennig1, Andreas Harloff1 1Albert-Ludwigs Universität, Freiburg, Germany

The composition of high-grade internal carotid artery (ICA) stenosis is one major determinant for the occurrence and recurrence of ischemic stroke. MRI has been greatly improved over the past decade and proven to be useful in tissue classification and detection of thrombi in patients with high-risk carotid artery plaques. In our study, we evaluated the additional impact provided by T2* gradient echo imaging at ultra-high field MRI (9.4T) for the enhanced discrimination between plaque calcification, acute and old hemorrhage and the detection of intra-luminal thrombi.

11:30 289. High-Resolution MRI of Implanted Skin Chambers with Integrated Coils Michael Bock1, Eva Christina Wönne1, Fabian Kiessling1, Wolfhard Semmler1, Reiner Umathum1 1Deutsches Krebsforschungszentrum (dkfz), Heidelberg, Germany

The interaction of different cell types with tissue can be studied in a living animal with the help of a skin chamber that is surgically implanted under the skin. In this work two types of inductively coupled coils were integrated into skin chambers to enhance the signal from the interior of the chamber. MR images with isotropic 100 μm resolution have been acquired in mice at 1.5T and 3T in less than 10 min, which clearly show the neovasculature induced by tumor cells in the chamber.

11:42 290. Evaluation and Correction of Noise and Resolution Induced Errors in Quantitative Trabecular Bone μMRI Charles Qingchuan Li1, Jeremy F. Magland1, Chamith S. Rajapakse1, X Edward Guo2, Xiaohui Henry Zhang2, Felix W. Wehrli1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA; 2Columbia University, New York City, New York, USA

Magnetic resonance micro-imaging (μMRI), in conjunction with digital image processing techniques, has been shown to be capable of non-invasively imaging trabecular bone and assessing structural changes caused by osteodegenerative disease. This work evaluated the effects of image noise and resolution on the accuracy of the derived structural parameters, and explored potential methods for correcting such errors. By simulating μMR images with controlled levels of noise and resolution, structural parameter calculations were shown to be skewed in a systematic but correctable manner.

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11:54 291. A Closer Look Into "DESIRE" for NMR Microscopy Markus Weiger1, Michael Fey1 1Bruker BioSpin AG, Faellanden, Switzerland

An extensive analysis of the alternative NMR microscopy technique DESIRE is presented. Simulations and experiments are used to investigate the aspects of signal enhancement, true spatial resolution, and contrast in structured objects.

12:06 292. Investigating Spatial Variances in MR Using Molecular Information from MALDI Imaging Mass Spectrometry Tuhin Kumar Sinha1, Zhengyu Yang1, William Michael Hardesty1, John C. Gore1 1Vanderbilt University, Nashville, USA

We demonstrate a method to investigate the systematic spatial variances found in MR images using MALDI imaging mass spectrometry. Using this technique we are able to correlate the observed MR relaxation phenomena with the underlying tissue composition. This research is aimed at determining which factors in tissue govern the contrast in MR imaging.

12:18 293. Fully-Integrated MR–Optical Imaging Concept for Pre-Clinical Applications Joerg Peter1, Reiner Umathum1, Katharina Schneider1, Gregor Schlosser1, Matthias Korn1, Michael Bock1, Wolfhard Semmler1 1German Cancer Research Center, Heidelberg, Germany

We propose a method and apparatus for integrated optical and magnetic resonance imaging of in vivo distributions of fluorescent or bioluminescent probes and simultaneous detection of nuclear magnetic resonance signals in small objects, e.g. in mice. The method is based on an MRI-compatible light detector in which a photon sensor is placed at the focal plane of a microlens array. The apparatus has been validated by means of experimental phantom studies. Its preclinical use is proposed for solving problems connected to separately imaging optical and NMR signals, as for instance direct study and comparison of

tracer/marker kinetics.

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GOLD CORPORATE MEMBER LUNCHTIME SYMPOSIUM Philips Medical Systems Hall F 12:30 – 13:30

Update on NSF Room 801 A/B 13:30-15:30 Chairs: Georg Bongartz and Hero K. Hussain

13:30 Invited Speaker: Current Insights into NSF Tim Leiner Maastricht University Hospital, Masstricht, The Netherlands

13:42 294. Incidence of NSF at Two Large Medical Centers Martin R. Prince1, Honglei Zhang2, Michael Morris3, Jennifer MacGregor4, Jeffrey Silbertsweig5, Marc E. Grossman4, Anthony M. Valeri4, Cynthia Magro1, Robert DeLapaz4, Henry Lee1, David N. Silvers4 1Weill Medical College of Cornell University, New York, New York, USA; 2Weill Medcial College of Cornell University, New York, New York, USA; 3Columbia University , New York, New York, USA; 4Columbia University, New York, New York, USA; 5Rochefeller University, New York, New York, USA

Ten years of medical records were reviewed to identify biopsy-confirmed cases of NSF and the number of patients undergoing GBCA enhanced MRI. Maximum risk of NSF, 8 of 22 (36%) patients, occured in dialysis patients with pro-inflammatory events receiving high-dose gadodiamide without undergoing dialysis for ≥ 3 days. Dialysis within one day following gadodiamide reduces risk to 1/127 (0.8%). Acute renal failure with rising serum creatinine is higher risk than severe chronic renal insufficiency. Risk of NSF with single dose GBCA was 0 in 63597 patients. A minority of NSF (7/25) cases were unrelated to GBCA exposure.

13:54 295. The Prevalence of Nephrogenic Systemic Fibrosis in Patients with Renal Failure Who Have Received Gadopentetate Dimeglumine Thomas A. Hope1, Robert J. Herfkens, Eli Weil 1Kaiser San Francisco, San Francisco, California , USA

This study intends to determine the risk of developing Nephrogenic Systemic Fibrosis (NSF) in dialysis dependent patients and those with elevated creatinines who have received gadopentetate dimeglumine. No previous study has published an incidence using gadopentetate dimeglumine. During the study period there were MRAs in 442 dialysis dependent patients and 3,065 patients with creatinines < 1.8. Our preliminary results show a lower prevalence of developing NSF in patients with renal disease than has previously been reported.

14:06 296. Preclinical Studies to Investigate the Development of NSF: Experiments in Renally Impaired Rats Martin A. Sieber1, Thomas Frenzel, Philipp Lengsfeld, Joachim Hütter2, Hubertus Pietsch1 1Bayer Schering Pharma AG, Berlin, Germany; 2Bayer Schering Pharma AG, Germany

Nephrogenic Systemic Fibrosis (NSF) is only observed in patients with severe renal dysfunction and a role for Gadolinium-based contrast agents (GBCAs) as a possible trigger has been suggested. The objective of this study was to evaluate the impact of prolonged circulation time of GBCAs on the onset of NSF-like signs in renal impaired rats. A prolonged circulation time for linear contrast agents due to reduced renal elimination correlated with an increased Gd retention in skin, in particular after administration of non-ionic linear GBCAs. For macro-cyclic compounds, no long-term retention of Gd in the skin could be observed.

14:18 297. Is Chronic Liver Disease an Independent Risk Factor for Nephrogenic Systemic Fibrosis? a Comprehensive Literature Review Sameer M. Mazhar1, Masoud Shiehmorteza1, Chad A. Kohl1, Jamey Allen1, Michael S. Middleton1, Claude B. Sirlin1 1University of California, San Diego, San Diego, California , USA

There have been increasing concerns of nephrogenic systemic fibrosis (NSF) in patients with chronic liver disease, as evidenced by the FDA’s black box warning cautioning against the use of gadolinium-based contrast agents in liver patients with renal insufficiency in the setting of hepatorenal syndrome or the perioperative liver transplantation period. We performed a comprehensive review of the NSF literature to characterize NSF in patients with chronic liver disease. A total of 291 unique patients were identified, 34 of whom (11.7%) had liver disease. Analysis revealed that liver disease does not appear to be an independent risk factor for NSF.

14:30 298. Prevalence of Nephrogenic Systemic Fibrosis in Patients with Chronic Liver Disease Zeke W. Foster1, Kendal Martin, Chad A. Kohl2, Masoud Shiehmorteza2, Sameer M. Mazhar2, Lillian O. Pacheco2, Jamey Allen2, Claude B. Sirlin2 1The Ohio State University School of Medicine, Columbus, USA; 2UCSD, San Diego, USA

Purpose: To determine the prevalence of nephrogenic systemic fibrosis (NSF) in patients with chronic liver disease exposed to gadolinium-based contrast agents.Methods: Retrospective review of 500 patients with chronic liver disease with gadolinium-enhanced MRI scans.Results: None of the 500 patients reviewed developed a fibrotic dermopathy consistent with NSF. Conclusions: Liver disease does not appear to substantially increase the risk for NSF development.

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14:42 299. An Interaction of Gadodiamide with Cu+2 and Zn+2 Joseph P. Hornak1, Brittany Lipchick1, Melissa Monahan1 1RIT, Rochester, New York, USA

NMR relaxometric data of mixtures of gadodiamide with copper and zinc indicate different interactions between the contrast agent and two metals. Two copper ions complex with the gadodiamide ligand DTPA-BMA. No clear complex ratio was seen for the zinc.

14:54 300. Evidence for Weak Protein Binding of Commercial Extracellular Gadolinium Contrast Agents Peter Caravan1, Yan Wang, Marga Spiller 1Massachusetts General Hospital, Charlestown, Massachusetts, USA

It is widely assumed that extracellular fluid Gd-based contrast agents do not bind to proteins. We used relaxometry (NMRD) to demonstrate that commercial GdDTPA (ionic) and GdDTPA-BMA (non-ionic) contrast agents do exhibit weak protein binding and that the extent of binding depends on the specific protein and the specific contrast agent. These results have implications for estimating in vivo Gd concentration from T1 changes, and may be important for understanding differences in the biological activity of these agents.

15:06 301. Long-Term Retention of Gadolinium in the Skin of Rodents Following the Administration of Gadolinium Based Contrast Agents Martin A. Sieber1, Thomas Frenzel, Philipp Lengsfeld, Joachim Hütter2, Hubertus Pietsch2 1Bayer Schering Pharma AG, Berlin, Germany; 2Bayer Schering Pharma AG, Germany

Several recent publications suggest a role for Gadolinium based contrast agents (GBCAs) as a possible trigger for Nephrogenic Systemic Fibrosis (NSF). The aim of the study was to evaluate the possible long-term retention of Gadolinium (Gd) in the skin of rodents following administration of different GBCAs. Gd-concentration in the skin was measured after application of linear non-ionic (Omniscan® and OptiMARK®); linear ionic (Magnevist®); macro-cyclic GBCAs (Gadovist®, ProHance® and Dotarem®). Regarding the Gd-concentration in the skin, we observed statically significant differences between the different GBCAs classes.

13:39 302. Characterization of Renal Masses with Arterial Spin Labeling MRI in Patients with Impaired Renal Function in the Era of Nephrogenic Systemic Fibrosis Ivan Pedrosa1, Philip Robson1, Martin P. Smith1, Andrew Wagner1, Neil M. Rofsky1, David Alsop1 1Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA

Magnetic Resonance (MR) imaging has played an important role in the characterization of renal tumors over the last years, particularly in the setting of impaired renal function where the nephrotoxic iodinated contrast agents used for computed tomography are not desirable. However, the recently reported association between gadolinium-contrast agents and the systemic disease nephrogenic systemic fibrosis has limited the use of these contrast agents in patients with moderate-to-severe renal insufficiency. Alternative imaging techniques for these patients that provide accurate differentiation between non-neoplastic and neoplastic renal masses based on their perfusion is mandatory in clinical practice. This abstract presents our initial experience with an arterial spin labeling (ASL) MR imaging technique, for the characterization of renal masses in patients with impaired renal function.

MRI of Cerebral Ischemia in Animals & Humans Room 701 A 13:30-15:30 Chairs: Timothy Q. Duong and Mathias Hoehn

13:30 303. Morphological and Functional Characterization of a New Model of Hypoxic-Ischemic Encephalopathy in Neonatal Rat Using a Bilateral Carotid Artery Occlusion Rebecca Recker1, Arash Adami1, Beatriz Tone1, Rich Hartman1, Jerome Badaut2, Hui Tian1, Stephen Ashwal1, Andre Obenaus1 1Loma Linda University School of Medicine, Loma Linda, California , USA; 2Centre Hospitalier Universitaire Vadois, Lausanne, Switzerland

Neonatal hypoxic-ischemic encephalopathy clinically presents with global diffuse injury. However, the most popular rat pup models of neonatal HIE induce a focal unilateral injury. The bilateral carotid artery occlusion (BCAO) model has been shown to induce bilateral injury in 10d old rat pups, an age that developmentally correlates with the term neonate. T2 and DWI assessment of gradation of injury was obtained that allows for candidate selection for future therapeutic treatment. Injury stratification was performed using a novel rat pup scoring system (RPSS) system which correlated with lesion volume.

13:42 304. Susceptibility Weighted MRI for Detection and Staging of Angiogenesis After Stroke in Rats Quan Jiang1, 2, Lakshman Gollapalli2, Mark E. Haack2, 3, Guang Liang Ding1, Zheng Gang Zhang1, Li Zhang1, Lian Li1, Ying Wang1, James R. Ewing1, Jia Ni Hu2, Hassan Bagher-Ebadian1, Michael Chopp1 1Henry Ford Health System, Detroit, Michigan, USA; 2Wayne State University, Detroit, Michigan, USA; 3MRI Institute for Biomedical Research, Detroit, Michigan, USA

We investigated the evolution of angiogenesis using high-resolution susceptibility-weighted imaging incorporating phase information (SWI) after sildenafil treatment of embolic stroke. We demonstrate that SWI can detect and identify cerebral angiogenesis after ischemic stroke. By combining information from blood-to-brain transfer constant of Gd-DTPA (Ki) measurement, SWI can stage the progress of angiogenesis. SWI provides a direct measurement of angiogenesis, unlike indirect measurements of cerebral blood flow (CBF) and cerebral blood volume (CBV).

13:54 305. Edge Location of Sodium Accumulation in Focal Cerebral Ischemia in the Rat: ADC and 23Na MRI Victor E. Yushmanov1, Alexander Kharlamov1, Boris Yanovski1, George LaVerde2, Fernando E. Boada2, Stephen C. Jones1, 2 1Allegheny-Singer Research Institute, Pittsburgh, Pennsylvania, USA; 2University of Pittsburgh, Pittsburgh, Pennsylvania, USA

ADC and 23Na twisted projection MRI were compared and confirmed by histology and flame photometry in the rat brain after MCAO. Within an ADC-homogeneous infarct region, sites with an elevated rate of 23Na increase (slope, 22±4%/h, p<0.005 compared to 14%/h±1%/h in other ischemic regions) were observed. In the ischemic regions, there was no slope/ADC correlation between and within brains (P>0.4). Maximum slope was located near the stroke periphery in 7 animals. Differences in collateral circulation in the cortex and caudate putamen were not slope determinants (P>0.3). 23Na MRI is more sensitive than ADC for assessing regional ischemic damage.

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14:06 306. Imaging Macrophage Infiltration of Ischemic Tissue is Not Possible Following Transient Middle Cerebral Artery Occlusion Tracy Deanne Farr1, Jörg Seehafer2, Mathias Hoehn2 1Max-Plack Institute for Neurological Research , Cologne, Germany; 2Max-Plack Institute for Neurological Research, Cologne, Germany

There is concern that contrast in the ischemic brain, following systemic administration of iron oxide to label blood born macrophages, accumulates non-specifically. The results of this study support that. We administered contrast during a time of high peripheral macrophage activity following transient middle cerebral artery occlusion; an optimal model due to the delay in blood brain barrier breakdown, and the lack of erythrocyte accumulation and cerebral spinal fluid disruption. No changes in signal intensity that could be attributed to macrophage accumulation were observed in T2* or T1-weighted images and there were few iron positive macrophages in the histological sections.

14:18 307. Estimates of Relative Contrast Recirculation Obtained from Perfusion MRI: A Potential Tool for Guiding Treatment Decision in Acute Ischemic Stroke Sheng-Ping Wu1, Logi Vidarsson1, Jeff Winter1, David Mikulis2, Andrea Kassner1 1The Hospital for Sick Children and the University of Toronto, Toronto, Canada; 2The Toronto Western Hospital, Toronto, Canada

Permeability MRI has the potential to objectively guide rt-PA treatment of stroke and thereby reducing the risk of hemorrhagic transformation (HT). However, one limitation is the long scan time (~5 min), which is problematic for stroke patients. In contrast, perfusion MRI is part of the routine stroke protocol and allows extraction of a parameters called relative recirculation (rR). The purpose of this study was to determine the relative efficacy of rR, compared with permeability (KPS), for prediction of HT. Our results demonstrated that KPS (p<0.01) and rR (p<0.01) were significantly increased in patients with HT, compared with patients without HT. Furthermore, a significant correlation was observed between KPS and rR (r=0.85, p<0.001). Both parameters effectively predict HT, although, rR is more clinically feasible.

14:30 308. Diagnostic Impact of Aortic MRI at 3Tesla in Patients with Acute Cryptogenic Stroke Andreas Harloff1, Patrick Dudler1, Alex Frydrychowicz1, Christoph Strecker1, Anna Lena Stroh1, Annette Geibel1, Andreas Hetzel1, Cornelius Weiller1, Jürgen Hennig1, Michael Markl1 1Albert-Ludwigs Universität , Freiburg, Germany

The purpose of this study was to evaluate a new 3D MRI protocol for the reliable detection of aortic high-risk plaques compared to transesophageal echocardiography (TEE) and to test the reliability of additional MRI in stroke of undetermined etiology

14:42 309. Does Local AIF Improve Prediciton of Final Infarct? Soren Christensen1, 2, Fernando Calamante3, Ona Wu4, Thomalla Götz5, Jens Fiehler5, Jachim Rother5, Thomas Kucinski5, Leif Ostergaard2, Patricia Desmond1, Stephen Davis1 1University of Melbourne, Parkville, Australia; 2University of Aarhus, Aarhus, Denmark; 3Brain Research Institute, Melbourne, Australia; 4Massachusetts General Hospital, Boston, USA; 5University Medical Center Hamburg-Eppendorf, Hamburg, Germany

Two local AIF methods were compared to conventional processing (manual AIF selection from the contra lateral hemisphere) by ROC analysis in a retrospective study of 104 acute (<6h) stroke patients. The final infarct lesion was delineated on the follow up MRI and used as infarct/no infarct classifier on the acute PWI maps. Both local AIF techniques performed marginally inferior to conventional processing. We speculate that: 1) AIFs selected on distal branches signals of the arterial tree might not represent the true AIF. 2) Delay and dispersion provide predictive information that should not be discarded from local AIF estimates.

14:54 310. Prediction of Hemorrhagic Transformation in Acute Ischemic Stroke: MRI Texture Analysis Versus Visual Inspection of Gd Enhancement Fang Liu1, George Tomlinson2, David Mikulis3, Frank Silver3, Andrea Kassner1 1The Hospital for Sick Children and the University of Toronto, Toronto, Canada; 2The University of Toronto, Toronto, Canada; 3The Toronto Western Hospital, Toronto, Canada

Hemorrhagic transformation (HT) is a potentially fatal complication of thrombolytic therapy in acute ischemic stroke (AIS). Early prediction of HT could substantially improve the safety of this therapy, thereby improving patient outcome. Early Gadolinium (Gd) enhancement on post-contrast T1-weighted MRI has been used to predict HT in subacute stroke. However, assessment at earlier time points (< 4 hours from symptom onset) did not reliably predict HT. An alternative to visual inspection is texture analysis, which discriminates textural information related to higher-order statistics and spectral properties not obvious to even an expert eye (trained radiologist). This method can quantify dependencies between neighboring pixels as well as patterns of variation within a region-of-interest. In this study we performed texture analysis,based on a co-occurrence matrix of post-contrast T1w images, to assess the prediction of HT in AIS patients and to compare it with visual inspection of Gd enhancement. Our results show that texture analysis of post T1-weighted images is superior to visual inspection for the prediction of HT in early AIS. To our knowledge, this is the first application of texture analysis in AIS. Further studies are needed to validate our results.

15:06 311. BOLD MR Mapping of Cerebrovascular Reactivity in Patients with Arterial Steno-Occlusive Disease: Validation by Arterial Spin Labeling MRI Daniel M. Mandell1, 2, Jay S. Han, 23, Julien Poublanc1, Adrian P. Crawley1, Jeff A. Stainsby, 1, Joseph A. Fisher, 23, David J. Mikulis1, 2 1Toronto Western Hospital, Toronto, Canada; 2University of Toronto, Toronto, Canada; 3Toronto General Hospital, Toronto, Canada

An emerging technique for mapping cerebrovascular reserve uses inhaled CO2 as a vasodilatory stimulus, and BOLD MR as an index of CBF changes. While BOLD MR signal reflects CBF, it also depends on cerebral blood volume, cerebral metabolic rate, arterial oxygenation, and hematocrit. We performed both BOLD and arterial spin labelling MR mapping of reserve in 25 patients with arterial steno-occlusive disease. ASL MR acted as a reference standard for measurement of CBF changes. BOLD and ASL MR measurements were highly correlated, suggesting BOLD MR is a reasonable surrogate for CBF imaging to map cerebrovascular reserve in this patient population.

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15:18 312. Asymmetry and Flow Dynamics in the Vertebrobasilar System as Assessed by Vessel Encoded Arterial Spin Labeling Akash P. Kansagra1, Eric C. Wong1 1University of California, San Diego, La Jolla, California , USA

Vessel encoded ASL allows quantitative and efficient imaging of cerebral vascular territories. Here, we discuss the application of vessel encoded ASL to reveal vertebral artery territories in five healthy subjects. In particular, we depict examples of vertebral artery territories and comment on unusual territorial morphology, with particular attention to asymmetry and mixing within the vertebrobasilar system.

Coronary MRA & Vessel Wall Room 701 B 13:30-15:30 Chairs: David A. Bluemke and Reza Nezafat

13:30 313. Multi-Phase Fat-Suppressed 3D SSFP for Robust Coronary Artery Imaging: Improvements Over the Single Phase Technique Maggie M. Fung1, Vincent B. Ho2, Maureen N. Hood2, Ehud J. Schmidt3 1GE Healthcare, Bethesda, Maryland, USA; 2National Naval Medical Center, Bethesda, Maryland, USA; 3GE Healthcare, Boston, Massachusetts, USA

The proper selection of the “quiet”, motion-less phase is a critical parameter in visualizing sharp vessels in coronary artery imaging. We show that the use of a multi-phase fat-suppressed 3D SSFP technique, which produces images at 3-4 cardiac phases, eliminates the need for accurate trigger delay selection in coronary artery imaging, and consistently produces better image quality relative to a single-phase acquisition. Intermittent fat suppression with Kaiser ramp steady state preparation was used to maintain fat suppression across multiple phases. Leading and trailing navigator were used to suppress respiratory motion that might occur within the lengthened multi-phase acquisition window.

13:42 314. 128-Channel Highly-Accelerated Breath-Held 3D Coronary MR Imaging Ajit Shankaranarayanan1, Maggie Fung2, Phil Beatty1, Dan Blezek3, Tom Foo3, Luca Marinelli3, Randy Giaquinto3, Robert Darrow3, Eric Fiveland3, Ehud Schmidt4, Chris J. Hardy3 1GE Healthcare, Menlo Park, California , USA; 2GE Healthcare, Bethesda, Maryland, USA; 3GE Healthcare, Niskayuna, New York, USA; 4GE Healthcare, Boston, Massachusetts, USA

3D whole heart imaging specifically targeted towards coronary artery imaging with a highly accelerated breath-hold acquisition on a 128-channel system has been demonstrated here. Such a combination may enable high-resolution CAI with greater reliability due to the possibility of simultaneously reducing, both the window in the cardiac cycle, and the total acquisition time.

13:54 315. Diagnostic Value of Contrast-Enhanced Whole-Heart Coronary MRA at 3.0Tesla Qi Yang1, Debiao Li, Xiaoming Bi, Jing An, Qiang Zhang, Renate Jerecic, Kuncheng Li1 1Xuanwu Hospital,Capital Medical University, Beijing, People's Republic of China

Coronary MRI at 3 Tesla imaging is attractive because the SNR gain from 1.5 to 3 Tesla can be traded to improve the spatial resolution and/or decrease the imaging time.Our study aims at evaluating a new imaging technique at 3T for high-resolution, high-contrast visualization of coronary arteries and for the accurate detection of significant coronary artery disease.

14:06 316. Improved Coronary MRA Using Wideband SSFP at 3 Tesla with Sub-Millimeter Resolution Hsu-Lei Lee1, Ajit Shankaranarayanan2, Gerald M. Pohost1, Krishna S. Nayak1 1University of Southern California, Los Angeles, California , USA; 2GE, Waukesha, Wisconsin, USA

Coronary artery imaging using SSFP at 3 Tesla exhibits high SNR and CNR, however off-resonance effects limit the TR and hence the achievable spatial resolution. Wideband SSFP sequences utilize an oscillating steady state to suppress off-resonance artifacts and therefore improve spatial resolution. Coronary artery images were obtained at 3T using three-dimensional navigated GRE, SSFP, and wideband SSFP sequences, with an in-plane resolution of 0.68 mm in the frequency-encoding direction. Wideband SSFP successfully suppressed banding artifacts, and is a promising approach for obtaining non-contrast, high-resolution coronary artery images at 3T with reliable image quality.

14:18 317. Contrast-Enhanced Whole-Heart Coronary MRA with Self-Timing and Respiratory Self-Gating Peng Lai1, Xiaoming Bi2, Himanshu Bhat1, Andrew C. Larson1, Renate Jerecic2, Debiao Li1 1Northwestern University, Chicago, Illinois, USA; 2Siemens Medical Solutions, Chicago, Illinois, USA

Whole-heart contrast-enhanced coronary MRA (CE-CMRA) has been proven to be effective at 3T. However, due to the subject-dependent contrast kinetics and variations in heart rates and breathing patterns, optimal timing of data acquisition is complicated. Also, accurate measurement of breathing-induced heart motion remains critical for respiratory gating. In this study, a new technique for whole-heart CE-CMRA with both self-timing and respiratory self-gating was developed. In comparison to the conventional approach, the proposed self-timing approach can improve both SNR and CNR. The RSG method with direct heart position measurement can potentially better suppress respiratory motion than NAV.

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14:30 318. MRI Detects Increased Coronary Wall Thickness in Asymptomatic Individuals: the Multi-Ethnic Study of Atherosclerosis (MESA) Robson Macedo1, Shaoguang Chen1, Shenghan Lai2, Steven Shea3, Ashkan Malayeri1, Moyses Szklo4, Joao Lima1, Debiao Li5, Kiang Liu, David A. Bluemke6 1Johns Hopkins, Baltimore, Maryland, USA; 2Baltimore, Baltimore, Maryland, USA; 3Siemens Medical Systems, Baltimore, Maryland, USA; 4Johns Hopkins School of Public Health, Baltimore, Maryland, USA; 5Radiology, Chicago, Illinois, USA; 6Johns Hopkins University, Baltimore, Maryland, USA

Coronary wall magnetic resonance imaging (MRI) is a noninvasive method for evaluation of arterial wall remodeling associated with atherosclerosis. Asymptomatic participants of the Multi-Ethnic Study of Atherosclerosis (MESA) study were studied using black blood MRI. MRI assessed coronary wall thickness was compared to computed tomography calcium score, carotid intimal-medial thickness and risk factors for coronary artery disease. Coronary artery wall MRI detects increased coronary wall thickness in asymptomatic individuals with subclinical markers of atherosclerotic disease and in individuals with zero calcium score.

14:42 319. MR Imaging of the Coronary Vessel Wall: Comparison of Vessel Wall Characteristics in Patients with Coronary Artery Disease and Age-Matched Healthy Controls Suzanne C. Gerretsen1, 2, Marianne E. Kooi1, 2, René M. Botnar3, Marcus Katoh4, Rob J. van der Geest5, Johannes Waltenberger1, 2, Jos M.A. van Engelshoven1, 2, Tim Leiner1, 2 1Maastricht University Hospital, Maastricht, Netherlands; 2Maastricht University, Maastricht, Netherlands; 3Technical University Munich, Munich, Germany; 4Saarland University Hospital, Homburg/Saar, Germany; 5Leiden University Medical Center, Leiden, Netherlands

The purpose of this study was to investigate differences in vessel wall characteristics at longitudinal MR coronary vessel wall imaging in patients with angiographically proven coronary artery disease (CAD) and a control group of age-matched healthy volunteers. 22 patients and 26 healthy volunteers underwent coronary vessel wall imaging. MR imaging can be used to non-invasively visualize the coronary vessel wall and to detect the presence of (sub)clinical coronary atherosclerosis. This study showed a significantly higher SI as well as increased wall thickness in patients with CAD compared to age-matched healthy volunteers. The significance of this phenomenon remains to be determined.

14:54 320. Evaluating Coronary Atherosclerotic Plaque Enhancement by Contrast-Enhanced Navigator-Gated 3D-SSFP Sequence Tao Li1, Hong Shao Zhao1, Quan Liu Cheng1, Long Zu Cai1, Li Yang1, Hai Xi Zhao1 1PLA General Hospital, Peking, People's Republic of China

The vulnerability of coronary atherosclerotic plaques often results in cardiovascular events. Various techniques have been used in evaluating the vulnerable plaque. Contrast-enhanced MRA bright blood technique using Gd-DTPA has the capacity of visualizing human coronary atherosclerotic plaques. Enhancement of plaques can also be detected on contrast-enhanced MRA. The plaques enhancement may indicate the vulnerability. This work is to evaluate plaque enhancement using contrast-enhanced navigator-gated 3D-SSFP sequence.

15:06 321. Molecular MRI of Vascular Remodeling in a Swine Model of Coronary Injury Using an Elastin-Binding Contrast Agent Christian von Bary1, Anne Preissel1, Elmar Spuentrup2, Alexandra Keithahn1, Sylvia Schachoff1, Simon Robinson3, Joel Lazewatsky3, Markus Schwaiger1, Joerg Hausleiter1, Rene Michael Botnar4 1Klinikum rechts der Isar, Munich, Germany; 2University Hospital Köln, Cologne, Germany; 3Bristol-Myers Squibb, North Billerica, USA; 4King's College London, London, UK

We sought to demonstrate the feasibility of imaging vascular remodeling in a porcine model of coronary injury using BMS753951, a novel elastin-binding low molecular weight contrast agent.

15:18 322. Black-Blood T1 Mapping for Quantitative Molecular Coronary Vessel Wall Imaging Using Elastine-Binding Contrast Agents Christian Stehning1, Christian von Bary2, Anne Preissel2, Simon Robinson3, Andreas Steingötter4, Hannes Dahnke1, René Michael Botnar4 1Philips Research, Hamburg, Germany; 2Technische Universität, München, Germany; 3Bristol-Myers Squibb Medical Imaging, North Billerica, Massachusetts, USA; 4Klinikum rechts der Isar, München, Germany

An ECG-triggered, navigator-gated black blood T1 mapping sequence is presented. It allows for the quantification of an elastin-targeted contrast agent in the coronary vessel wall. SPECIAL SYMPOSIUM Image Processing Room 715 A/B 13:30 – 15:30 Chairs: David J. Hawkes and Mark Jenkinson

Educational Objectives: Upon completion of this session, participants should be able to:

• Explain how several basic image processing methods work and be able to choose appropriate techniques for relevant application problems; • Describe several methods for segmenting images and understand their limitations; and • Describe the fundamental aspects of registration and shape-based analysis and know how to apply them in practice.

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14:00 Foundations of Image Processing Chloe Hutton

14:30 Segmentation Simon K. Warfield 15:00 Linear and Non-Linear Registration Gary E. Christensen

14:30 Segmentation Simon K. Warfield 15:00 Shaped-Based Analysis Timothy F. Cootes

Cartilage Imaging: Methods Room 717 A/B 13:30-15:30 Chairs: Peter Hardy and Sharmila Majumdar

13:30 323. gagCEST & NOE: Assessment of Glycosaminoglycan Concentration in Vivo Wen Ling1, Ravinder R. Regatte2, Gil Navon1, Alexej Jerschow2 1Tel Aviv University, Israel; 2New York University, New York, New York, USA

Glycosaminogycan (GAG) plays numerous vital functions in the human body. GAG concentration [GAG] in vivo is a sensitive biomarker indicative of both osteoarthritis (OA) and intervertebral disk (IVD) degenerative diseases. Currently existing techniques for GAG monitoring, such as, dGEMRIC (delayed gadolinium-enhanced MRI contrast), T1?, and 23Na MRI have some practical limitations. By exploiting the exchangeable protons of GAG we demonstrate that one can directly map the localized GAG concentration in vivo (gagCEST). The gagCEST approach is exploited on both human articular cartilage and animal IVD. Moreover, we also report the observation of the Nuclear Overhauser effect (NOE) from macromolecules in tissue, which contributes significantly to CEST/MT contrast mechanism in MRI and may lead to further diagnostic abilities.

13:42 324. In Vivo Measurement of 23Na T2* in Human Articular Cartilage at 3T and 7T Ernesto Staroswiecki1, 2, Neal Kepler Bangerter1, Paul Thomas Gurney1, Garry Evan Gold1, Samantha Jane Holdsworth1, Thomas Grafendorfer2, Brian Andrew Hargreaves1 1Stanford University, Stanford, USA; 2GE Healthcare, Waukesha, USA

Quantification of sodium in cartilage correlates positively with proteoglycan content, making sodium MRI very attractive for tracking early degenerative changes associated with osteoarthritis. However, the challenges associated with in-vivo sodium imaging, including extremely rapid T2 relaxation decay, low concentration, and low gyromagnetic ratio, have hindered its adoption. Short-TE gradient-spoiled sequences with efficient k-space trajectories can improve image quality. Accurate characterization of sodium T2* in the tissue of interest improves sequence parameter optimization and may be a marker of underlying physiologic structure. In this work we present in-vivo measurements of sodium T2* in human articular cartilage at 3T and 7T.

13:54 325. T1ρ Relaxation Time of Lateral Meniscus and Its Relationship with T1ρ of Adjacent Cartilage in Knees with Acute ACL Injuries at 3T Radu Ioan Bolbos1, Benjamin C. Ma1, Thomas M. Link1, Sharmila Majumdar1, Xiaojuan Li1 1University of California San Francisco, San Francisco, USA

Meniscus injury and cartilage degenerations preceded by damage of the collagen-proteoglycan (PG) matrix are present in acute knee injuries such as ACL tear. Previous studies have suggested potential associated degenerative processes of proteoglycans in meniscus and cartilage. T1 ρ relaxation time mapping techniques were used to assess lateral meniscus and adjacent cartilage in 16 patients with ACL tears. T1 ρ elevation in posterior horn of meniscus was significantly correlated with cartilage T1 ρ elevation in posterior compartment of LT, which demonstrated a strong injury-related relationship between meniscus and cartilage biochemical changes.

14:06 326. Detection of Proteoglycan Content in Human Osteoarthritic Cartilage Samples with Magnetic Resonance T1rho Imaging Jonathan Cheng1, Ehsan Saadat1, Radu Ioan Bolbos1, Bjoern Jobke1, Sarmad Muneeb Siddiqui1, 2, Michael D. Ries1, Thomas M. Link1, Xiaojuan Li1, Sharmila Majumdar1 1University of California, San Francisco, San Francisco, California , USA; 2University of California, Berkeley, Berkeley, California , USA

We demonstrated that MR T1rho imaging is capable of quantifying proteoglycan (PG) content in human osteoarthritic articular cartilage. Human cartilage samples were harvested from total knee arthroplasty surgeries and imaged with T1rho ex vivo. Later, biopsy punches were taken from the samples and proteoglycan content was determined biochemically. T1rho relaxation times and PG content were significantly negatively correlated, showing a potential for T1rho to predict PG content in vivo.

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14:18 327. Local Flip Angle Correction for Improved Volume T1-Quantification in 3D DGEMRIC Using the Look-Locker Technique Carl Siversson1, Carl-Johan Tiderius1, Leif Dahlberg1, Jonas Svensson1 1Lund University, Malmo, Sweden

In 3D Look-Locker delayed Gadolinium enhanced MRI of cartilage (dGEMRIC) local flip angle variations may cause erroneous T1 values. The aim of this work was to evaluate the extent of this effect and try to correct for it in in vivo data. This was achieved by calculating and compensating for the local flip angle as it varies in the slice encoding direction, thus extending the number of slices usable for the dGEMRIC measurement.

14:30 328. Fast 3D T1 Mapping with Variable Flip Angle Method for DGEMRIC: Preliminary Validation Wei Li1, Nitya Krishnan2, Pottumarthi V. Prasad1 1Evanston Hospital and Northwestern University Feinberg School of Medicine, Evanston, Illinois, USA; 2Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA

The purpose of this study was to validate the accuracy of VFA approach for dGEMRIC in both phantoms and in vivo compared to standard 2D IR-TSE technique. Two separate phantom tests, one for estimating the optimal flip-angle combination and the other for evaluating the spread in T1 values across slices were performed. Four OA patients and 4 healthy human subjects were imaged sagittally using 2D IR-TSE and 3D VFA sequences. Our preliminary results indicate that VFA method is able to provide adequate accuracy of T1 for dGEMRIC, with major advantages of entire joint coverage and shorter acquisition times.

14:42 329. Multiparametric MRI Characterization of Degradation in Bovine Nasal Cartilage Ping-Chang Lin1, Kenneth W. Fishbein1, Richard G. Spencer1 1National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA

Mono-parametric characterization of cartilage with MRI has met with limited success; there is a large degree of overlap in mean parameter values for e.g. normal and OA cartilage. We extend MRI analysis of cartilage by delineating the relationship between pairs of MR parameters pre- and post-enzymatic degradation. Results are visualized as clusters of parameter values in two-dimensional space, with axes consisting of T1, T2, and MT rate taken pairwise. We find that parameter clusters exhibit motion in parameter space defined by translation, rotation, and changes in shape and size, with differences seen between trypsin and collagenase digestion.

14:54 330. Multiparametric Characterization of Healthy and Diseased Articular Cartilage at 17.6T: Early Results Jose G. Raya1, Gerd Melkus2, Olaf Dietrich1, Daniel Ludwig Weber2, Lucianna Filidoro1, Maimilian Felix Reiser1, Peter Michael Jakob2, Christian Glaser1 1Ludwig Maximilian University of Munich, Munich, Germany; 2University of Würzburg, Würzburg, Germany

Articular cartilage is a highly structured tissue and plays an important role in the pathogenesis of osteoarthritis. The purpose of this work was to establish a protocol for multiparametric (T2, T1, ADC and FA) examination of healthy and diseased articular cartilage at 17.6T. Three differentiated zones (radial, transitional and tangential) could be identified in healthy cartilage, whereas no transitional zone was present in diseased cartilage. ADC and T2 were increased and FA reduced on diseased cartilage. Lesions appeared larger in the ADC and FA maps than in T2 maps indicating a higher sensitivity of DTI to loss of cartilage integrity.

15:06 331. Accelerated T2 Mapping of Articular Cartilage Using Iterative HYPR Joshua Jay Jacobson1, Rafael O'Halloran1, Alexey A. Samsonov1, Richard Kijowski1, Sean B. Fain1, Walter F. Block1 1University of Wisconsin Madison, Madison, Wisconsin, USA

T2 mapping can be used to quantify early changes consistent with cartilage degradation before changes can be detected in morphological scans. However, the lengthy scan times approaching 10 minutes limit their utilization. We recognize that recent methods to exploit temporal correlations in time-resolved imaging (HYPR) can be applied to parametric imaging, by simply replacing the temporal dimension with a parametric dimension. We present a method to utilize an iterative constrained reconstruction algorithm with an undersampled acquisition to reduce scan time by a factor of four.

15:18 332. Ultrashort TE Spectroscopic Imaging (UTESI) of the Short T2 Tissues in the Musculoskeletal System Jiang Du1, Atsushi Takahashi2, Christine B. Chung1, Graeme M. Bydder1 1University of California, San Diego, San Diego, California , USA; 2GE Healthcare Technologies, Menlo Park, California , USA

The human musculoskeletal (MSK) system contains a variety of tissues with short T2 components such as the deep layers of articular cartilage, menisci, ligaments, tendons, entheses and cortical bone. The 2D UTE sequences allow these previously “MR invisible” tissues to be directly imaged and quantified. Here we present a UTE spectroscopic imaging (UTESI) technique for high resolution imaging and quantification, and apply it to six types of short T2 tissues in the MSK on a clinical 3T scanner

Imaging in the Post-Nyquist Era Room 801 A/B 16:00-18:00 Chairs: Michael Lustig and Oliver Wieben

16:00 333. Dynamic Functional Volumetric Magnetic Resonance K-Space Inverse Imaging of Human Visual System Fa-Hsuan Lin1, 2, Thomas Witzel1, 3, Graham Wiggins1, Lawrence Wald1, John Belliveau1 1Massachusetts General Hospital, Charlestown, Massachusetts, USA; 2National Taiwan University, Taipei, Taiwan; 3Harvard-MIT Division of Health Sciences and Technology, Cambridge, Massachusetts, USA

We propose a K-space magnetic resonance Inverse Imaging (K-InI) approach to use a highly parallel radio-frequency coil array to achieve high temporal resolution MRI. K-InI solves an under-determined linear system using regularization in parallel MRI reconstruction. K-InI uses auto-calibration technique to estimate the reconstruction coefficients and it can provide coil-by-coil reconstruction to allow for more flexible combination of different channels in the coil array. We demonstrate K-InI using a 3D visual fMRI experiment to achieve 100 ms temporal resolution.

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16:12 334. High Spatial High Temporal Resolution MR-Encephalography Using Constraint Reconstruction Based on Regularization with Arbitrary Projections (COBRA) Thimo Grotz1, Benjamin Zahneisen1, Arsène Ella1, Jürgen Hennig1 1University Hospital Freiburg, Freiburg, Germany

MREG, also called inverse imaging, was introduced as a new approach to measure activation related MR-signal changes in the brain, with very high temporal resolu-tion. We present a constraint reconstruction based on regularization with arbitrary projections to localize the activation. The results demonstrate that COBRA with very low number of projections can be used to acquire activation maps with reasonable spatial resolution at very high temporal resolution. Signal time courses show excel-lent contrast-to-noise for the observed BOLD response.

16:24 335. Quantitative 23-Sodium and 17-Oxygen MR Imaging in Human Brain at 9.4 Tesla Enhanced by Constrained K-Space Reconstruction Ian C. Atkinson1, Keith R. Thulborn1, Aiming Lu1, Justin Haldar2, X J. Zhou1, Ted Claiborne1, Zhi-Pei Liang2 1University of Illinois-Chicago, Chicago, Illinois, USA; 2University of Illinois-Urbana-Champaign, Urbana, Illinois, USA

The sensitivity of ultra-high field MRI enables quantitative imaging of non-proton species such as 23-sodium and 17-oxygen. Constrained k-space reconstruction techniques can be used to improve the spatial resolution of the acquired data without compromising the ability to quantify the final image. This approach of enhanced image reconstruction combined with the improved sensitivity of high field broadens the human applications of metabolic MR imaging by minimizing otherwise long acquisition times to achieve adequate spatial resolution for the anatomy and SNR performance for quantification.

16:36 336. Highly Undersampled 3D Golden Ratio Radial Imaging with Iterative Reconstruction Mariya Doneva1, Holger Eggers2, Jürgen Rahmer2, Peter Börnert2, Alfred Mertins1 1University of Luebeck, Luebeck, Germany; 2Philips Research Europe, Hamburg, Germany

We illustrate the feasibility of Compressed Sensing for 3D dynamic imaging using highly undersampled 3D radial acquisition with golden ratio profile ordering. Image reconstruction from a low number of measurements could be very useful for dynamic 3D imaging, to reduce the often long acquisition times and thus improve temporal resolution in 3D MRI. Using CS, the aliasing artifacts were significantly reduced and a high frame rate was achieved, allowing dynamic imaging with good temporal resolution. The described approach could be particularly useful for dynamic studies of joint motion.

16:48 337. Three-Dimensional Compressed Sensing for Dynamic MRI Ali Bilgin1, 2, Ted P. Trouard1, Maria I. Altbach1, Natarajan Raghunand1 1University of Arizona, Tucson, Arizona , USA

Compressed Sensing (CS) theory illustrates that a small number of linear measurements can be sufficient to reconstruct sparse or compressible signals. we introduce a CS theory based method for reconstruction of time-varying radial k-space data by exploiting the spatio-temporal sparsity of Dynamic Contrast Enhanced (DCE) MRI images. The proposed method significantly reduces undersampling artifacts and can provide high temporal and spatial resolution.

17:00 338. Constrained Compressed Sensing for Fast 3D Visualization of Active Catheters Carsten Oliver Schirra1, 2, Sascha Krueger3, Steffen Weiss3, Reza Razavi1, Tobias Schaeffter1, Sebastian Kozerke2 1King's College London, London, UK; 2University and ETH Zurich, Zurich, Switzerland; 3Philips Medical Systems, Hamburg, Germany

With standard dynamic 3D imaging methods sufficient spatial resolution is difficult to achieve at the required temporal rates when visualizing interventional devices. Active catheters lend themselves well to undersampling methods given their confined sensitivity volume. Compressed Sensing allows exploiting the image sparseness inherent to images acquired with active catheter antennae, however the associated iterative reconstruction algorithms are time-expensive. In this work, the feasibility of using Compressed Sensing for accelerating 3D imaging of active catheters is investigated. Dedicated constraints are introduced taking into account the known catheter length and position in order to minimize the number of iterations in reconstruction.

17:12 339. HYPR-Constrained Compressed Sensing Reconstruction for Accelerated Time Resolved Imaging Huimin Wu1, Walter F. Block1, Alexey A. Samsonov1 1University of Wisconsin-Madison, Madison, USA

Constrained reconstruction methods have been shown to produce significant accelerations to date, but suffer some temporal inaccuracy when vessels with different temporal behaviors are nearby or as the sparsity of the image volume decreases. We present simulated comparisons of a single pass reconstruction method (Highly constrained Projection Local Reconstruction or HYPRLR) and an iterative constrained reconstruction method termed HYPR Reconstruction by Iterative Estimation (HYPRIT). We demonstrate increased temporal accuracy for HYPRIT relative to HYPR LR, but also demonstrate how HYPRIT’s performance improves when using the HYPR LR image as a constraining image. Finally, rapid CE-MRA capabilities are demonstrated.

17:24 340. A Comparison of L1 and L2 Norms as Temporal Constraints for Reconstruction of Undersampled Dynamic Contrast Enhanced Cardiac Scans with Respiratory Motion Ganesh Adluru1, 2, Edward VR DiBella1 1University of Utah, Salt Lake City, USA

Constrained reconstruction methods can be used to accelerate the acquisition of cardiac dynamic contrast-enhanced MRI data. The temporal constraint term is important for determining the quality of reconstructions from undersampled data. Here we compare and evaluate reconstructions obtained by using an L2-norm and an L1-norm as temporal constraints. The reconstructions were compared using data with simulated undersampling and using actual undersampled radial data acquired from the scanner. Using an L1-norm in the temporal constraint helps in obtaining better reconstructions as compared to using an L2-norm in the temporal constraint especially when there is respiratory motion in the data.

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17:36 341. Accelerated Dynamic Imaging by Reconstructing Sparse Differences Using Compressed Sensing André Fischer1, 2, Felix Breuer2, Martin Blaimer2, Nicole Seiberlich1, Peter Michael Jakob1, 2 1University of Wuerzburg, Wuerzburg, Germany; 2Research Center for Magnetic Resonance Bavaria e.V., Wuerzburg, Germany

The concept of Compressed Sensing offers a new perspective for accelerated magnet resonance imaging. We demonstrate the use of CS in connection with dynamic imaging. The proposed method reconstructs the differences between a certain timeframe and the composite image of a dynamic dataset. By choosing a radial trajectory, the artifacts in the undersampled image are incoherent, and, therefore, beneficial for the CS algorithm. We achieved good reconstructions with as less as 14 projections (192 x 192 matrix size). Hence, this technique is promising for future real-time dynamic applications.

17:48 342. MRI Compressed Sensing Via Sparsifying Images Alexey Samsonov1, Youngkyoo Jung1, Andrew L. Alexander1, Walter F. Block1, Aaron S. Field1 1University of Wisconsin, Madison, Wisconsin, USA

Recently, there has been an emerging interest to accelerate MRI through iterative reconstruction of undersampled data based on compressed sensing theory. We extend the compressed sensing framework via sparsifying images. The new method utilizes the recent idea in HYPR methods to use sliding window composite images to constrain reconstruction. At the same time, such enhancement is done within the compressed sensing framework. We demonstrate that the new method, HighlY constrained back PRojection by Iterative esTimation (HYPRIT), may be a powerful tool for image reconstruction from highly undersampled data. We demonstrate its potential for accelerated radial diffusion tensor imaging.

Beyond Components: Subsystems & Hybrids Room 718 A 16:00-18:00 Chairs: Richard W. Bowtell and Blaine A. Chronik

16:00 343. The Equivalent Magnetizing Current (EMC) Method for Biplanar Active and Passive Shim Design Hector Sanchez Lopez1, Feng Liu1, Adnan Trakic1, Ewald Weber1, Stuart Crozier1 1University of Queensland, Brisbane, Australia

This paper presents a new method for biplanar active and passive shim design using an Equivalent Magnetizing Current (EMC) method. The EMC induced by the rotational component of the magnetization is equivalent to that of the stream function (SF) and hence the SF is proportional to the magnetization. Using this approach, the magnetic field generated by a magnetized disk of finite thickness is related directly to the SF and hence no intermediate step to transform the current density into SF is required. Optionally, instead of a current pattern, a set of iron pieces can be employed so that the magnetized shims can be placed at equally spaced contours of the magnetization-stream function (MSF). The MSF is expressed as a sum of orthogonal functions of the azimuthal angle and shim domain radius and so it is tailored in the source domain in order to generate a particular magnetic field harmonic or a combination of these inside the DSV. The method is validated using known examples and the potential to generate new solutions is demonstrated.

16:12 344. Optimized Longitudinal and Transverse Gradient Coils with Up to Seven Imaging Regions Joshua Thomas de Bever1, 2, Blaine Alexander Chronik2 1University of Utah, Salt Lake City, USA; 2University of Western Ontario, London, Canada

Imaging of mice using MRI is a critical part of studies investigating the genetics behind human diseases such as cancer, atherosclerosis, and cardiac disease. It can take multiple hours to image a single mouse, and the number of mice required to properly complete a large experiment can be on the order of tens of thousands. A gradient coil insert with multiple imaging regions would allow significant increases in throughput while maintaining gradient strengths required for high performance imaging. This abstract presents the results of a systematic computer simulation design study of multiple-imaging-region (MIR) gradient coils. The parameter space has been mapped for both Longitudinal and Transverse gradients with one, two, three, four, five, and seven imaging regions.

16:24 345. Azimuthally Symmetric IBEM Gradient and Shim Coil Design Michael Stephen Poole1, Richard Bowtell1 1University of Nottingham, Nottingham, UK

Many coil systems required for MRI have a high degree of symmetry with the coils often being wound on a "surface of revolution" about the main field direction and the desired field variation generally has a known simple azimuthal dependence of the form cos(m φ) or sin(m φ). Incorporation of this a priori knowledge of the symmetry into the IBEM framework reduces the number of elements and consequently the computational effort and memory requirements. Here we demonstrate this by designing an insert head gradient formed from an array of annuli and a biradial ZX shim coil.

16:36 346. Asymmetric Head Gradient Coil for Imaging and Spectroscopy at 7T Dan Green1, Simon Pittard1, Robin A. de Graaf2, Terence W. Nixon2, Hoby P. Hetherington2 1Varian, Inc., Yarnton, UK; 2MRRC, Yale University, New Haven, Connecticut, USA

Many fast imaging and spectroscopy sequences are difficult at high field as they are very sensitive to magnetic field inhomogeneities. Greater importance is being placed on shimming the subject, with a number of studies outlining the required shim specifications, and the development of methods such as dynamic shimming. Here a new head-only asymmetric gradient set is described, featuring water-cooled active shims up to 3rd order, which are inductively and capacitively decoupled from the main gradients. A large patient bore (42cm) allows use of noise insulation and a variety of array coils.

16:48 347. Epoxy Parameters for High Partial Discharge Inspection Voltages Derek A. Seeber1, Anthony Mantone1, Weijun Yin2 1GE Healthcare, Florence, South Carolina, USA; 2GE Research, Niskayuna, New York, USA

The epoxy is an integral component for both mechanical support and electrical performance. Epoxy manufactures typically specify parameters describing the viscosity, glass transition temperature (Tg), thermal expansion (CTE), tensile, modulus, elongation, dielectric constant and dissipation factor. As a PDIV performance parameter is not specified by the manufactures of epoxy systems, a method must be developed to use the epoxy manufacture’s properties to ensure high PDIV for an MRI gradient coil.

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17:00 348. Experiments in Real-Time MRI with RT-Hawk and Medusa Pascal Stang1, Juan Santos1, John Pauly1, Greig Scott1 1Stanford University, Stanford, California , USA

Real-time MR imaging places substantial performance demands on console hardware, interface buses, and reconstruction software. Moreover, user interfaces and software must integrate tightly with the scanner to allow instantaneous changes to the pulse sequence. We present a real-time MRI receiver system based on the Medusa console and RT-Hawk control and reconstruction software. Using the system, we demonstrate real-time cardiac imaging at 50 frames per second. System limitations and bottlenecks are explored in the context of real-time operation, including the throughput and latency of Medusa’s USB 2.0 data transport.

17:12 349. Evaluation of a Combined Magnetic Resonance (MR)/ultra-Wideband (UWB)-Radar Technique Florian Thiel1, Werner Hoffmann1, Frank Wojcik1, Mathias Hein2, Jürgen Sachs2, Ulrich Schwarz2, Marko Helbig2, Frank Seifert1 1Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany; 2TU Ilmenau, Germany

This research aims at the synergetic use of ultra-wideband (UWB)-Radar technologies combined with magnetic resonance imaging (MRI), to gain complementary information, e.g. to accelerate cardiac MR imaging or to measure the electromagnetic wave propagation through heterogeneous, malignant and benign, biological tissue more accurately. We propose the multi-modal combination of MR and UWB-Radar for improved functional diagnosis and imaging.

17:24 350. Performance and in Vivo Applications of Simultaneous PET/MRI Hans F. Wehrl1, M S. Judenhofer1, M Becker2, G Reischl1, H J. Machulla1, C D. Claussen1, B J. Pichler1 1University of Tuebingen, Tuebingen, Germany; 2Bruker BioSpin MRI GmbH, Ettlingen, Germany

The combination of PET and MRI for simultaneous imaging paves the way for dual functional imaging. A small animal PET/MR system operating inside a 7 Tesla MR scanner is presented. An evaluation of the performance of a combined PET/MR system is given. In vivo studies in oncology, cardiology and brain perfusion have been performed in mouse models. In contrast to PET/CT the data from an integrated PET/MR system can be acquired simultaneously and thus, they can be temporally matched.

17:36 351. Design of a Combined PET and Field-Cycled MRI System for Small Animal Imaging Geron Andre Bindseil1, William Bradfield Handler1, Timothy James Scholl1, Kyle Michael Gilbert1, Hao Peng2, Blaine Alexander Chronik1 1University of Western Ontario, London, Canada; 2Stanford University, Stanford, USA

There is great interest in combining anatomical and functional imaging systems. Current approaches to PET/MRI either change PET to make it compatible with conventional MRI or change MRI to make it compatible with conventional PET. An approach of the latter kind is investigated and the design of a PET/Field-cycled MRI (FCMRI) system using the Siemens Inveon small-animal PET is proposed. Advantages of PET/FCMRI over other PET/MRI approaches for small-animal preclinical imaging are explored.

17:48 352. Split Cylindrical Gradient Coil for Combined PET-MR System Dan Green1, Simon Pittard1, Michael Poole2, Richard William Bowtell2, Rob C. Hawkes3, Alun J. Lucas3, T Adrian Carpenter3 1Varian, Inc., Yarnton, UK; 2University of Nottingham, Nottingham, UK; 3University of Cambridge, Cambridge, UK

One approach to simultaneous PET-MR is to place a PET ring in the gap of a split imaging magnet. In order to minimize interference between the MR and PET detection the gradient coils must also be split whilst retaining access to the imaging region. Here an Inverse Boundary Element Method (IBEM) is used to design actively-shielded cylindrical gradients with substantial central gaps. A full three-axis set has been designed, built and tested.

B1 Mapping: What's Your Angle Room 718 B 16:00-18:00 Chairs: Andrew C. Larson and Klaas Pruessmann

16:00 353. Improved B1-Mapping for Multi RF Transmit Systems Kay Nehrke1, Peter Börnert1 1Philips Research Europe, Hamburg, Germany

MRI based B1-mapping techniques potentially suffer from adverse error propagation in the range of small flip angles, resulting in noisy maps in regions of low B1. However, on multi-transmit systems the coil basis functions used for optimizing the RF waveforms may be freely chosen as a result of the linear properties of the transmit system. Hence, the RF field may be adapted to a favourable operational range of the B1-mapping technique by appropriate superposition of coils. In the present work, this approach was validated in phantom experiments, resulting in a strongly improved quality of the B1-maps.

16:12 354. A Matrix Approach for Mapping Array Transmit Fields in Under a Minute David Otto Brunner1, Klaas Paul Pruessmann1 1University and ETH Zurich, Zurich, Switzerland

Recently developed methods for mitigating inhomogeneous RF excitation at ultra-high fields such as RF-shimming or Transmit-SENSE rely on accurate maps of the excitation field of all individual elements. These maps must be acquired within the preparation phase of an experiment and hence under severe time and power constraints. However, the sensitivity of most mapping methods is very low since the flip angle achieved using a single element for excitation is very low. We present a matrix approach of measuring the excitation fields with high accuracy for an entire 8-channel array within 40 s measurement time.

16:24 355. Rapid Slice-Selective B1 Mapping for Transmit SENSE Adam Bruce Kerr1, Hans-Peter Fautz2, Mika W. Vogel2, Patrick Gross2, John Mark Pauly1, Yudong Zhu3 1Stanford University, Stanford, California , USA; 2GE, Munich, Germany; 3GE, Albany, New York, USA

Two slice-selective approaches for rapid estimation of B1 maps over a large dynamic range, including careful compensation of slice profile and off-resonance effects are presented. The methods are evaluated on an eight-channel parallel transmit 3T body array, and validated by presenting a successful demonstration of a 3D slice-selective parallel transmit excitation.

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16:36 356. A Fast 3D B1 Mapping Method at 3T Sha Zhao1, 2, Lloyd J. Gregory, 12, Geoffery J. Parker1 1The University of Manchester, Manchester, UK; 2Salford Royal NHS Trust Fund, Manchester, UK

We report a B1 mapping method at 3 T, based on a magnetisation preparation Turbo FLASH sequence. A series of acquisitions with different nominal preparation angles are used to calculate B1 efficiency at every voxel. This method is accurate, fast, capable of 3D volume coverage and has a low RF irradiation to the subjects. It is also easy to implement.

16:48 357. Whole Volume Three Dimensional B1 Mapping in 10 Seconds Olof Dahlqvist Leinhard1, 2, Marcel Jan Bertus Warntjes1, 2, Peter Lundberg1, 2 1Linköping University, Linköping, Sweden; 2Center for Medical Image Science and Visualization (CMIV), Linköping, Sweden

A method for whole volume three dimensional B1 mapping is presented. The method is based on measurement of the effect caused by a saturation pre-pulse in turbo field echo (TFE) pulse sequence and produces B1 field maps covering the brain in 10 seconds.

17:00 358. Simultaneous B0- And B1-Map Acquisition for Fast Localized Shim, Frequency and RF Power Determination in the Heart at 3T Michael Schär1, 2, Evert-Jan P. A. Vonken1, 3, Matthias Stuber1 1The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA; 2Philips Medical Systems, Cleveland, Ohio, USA; 3Utrecht University, Utrecht, Netherlands

Cardiac MRI and MRS at 3T are challenged by inhomogeneous B0- and B1-fields. A sequence is proposed to combine the acquisition of a B0- and a B1-map in a single breath-hold for fast determination of localized second order shim, resonance frequency F0, and RF power settings. It is shown in 5 volunteers that the determined shim and RF power settings allow to correct B0 field inhomogeneities and to accurately adjust the mean flip angle in a chosen region of interest in the heart.

17:12 359. Simultaneous Fast Quantitation of B1 and T1 Maps at 7 T Using the TESSA Principle Kai Zhong1, Oliver Speck2 1Otto-von-Guericke University , Magdeburg, Germany; 2Otto-von-Guericke University, Magdeburg, Germany

In this study, a new fast acquisition method based on the TESSA (Transition from Equilibrium into Steady State Acquisition) principle has been applied for simultaneous in vivo quantitation of B1 and T1 maps at 7 Tesla. This novel method utilizes the transient magnetization from equilibrium to steady state which otherwise is discarded and is self-contained, e.g. only a single acquisition is required to determine both B1 and T1. The new method has no specific requirement for the acquisition parameters TR and flip angle and has a 300% gain in speed. The TESSA principle could potentially stimulate further in vivo high field applications.

17:24 360. Fast Simultaneous Measurement of the RF Flip Angle and the Longitudinal Relaxation Time for Quantitative MRI Jung-Jiin Hsu1, Greg Zaharchuk1, Gary H. Glover1 1Stanford University, Stanford, USA

In quantitative MRI, measuring both the flip angle of an RF pulse and the longitudinal relaxation time T1 are critically important for pixel intensity normalization and for calculating physical quantities especially in longitudinal studiesand in imaging at high field. But conventional methods can only measure one ofthem and require long scan times. In this work, two novel methods are developed which can acquire multi-slice scan data in about half the time needed for a conventional flip-angle measurement, and both the flip angle and T1 can be determined simultaneously.

17:36 361. B1 Mapping Using Phase Information Created by Frequency-Modulated Pulses Jang-Yeon Park1, Michael Garwood1 1Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA

The most common B1 mapping approach is the double-angle method which uses the ratio of two images acquired with different flip angles, requiring TR >> T1. Recently, several methods have been proposed to shorten TR. Here, a new time-efficient method is introduced using π/2 and π hyperbolic secant pulses, where B1 map is determined by phase difference between two spin-echo images with opposite frequency sweeps. It can shorten TR because it uses phase, not signal magnitudes, and 2D multi-slice B1 map can be obtained. It can also avoid possible errors due to different slice profiles caused by different flip angles.

17:48 362. 3D B1+ Mapping with Multi-Slab Catalyzed Steady-State Double-Angle Method Dingxin Wang1, 2, Sven Zuehlsdorff2, Andrew Larson1 1Northwestern University, Chicago, Illinois, USA; 2Siemens Medical Solutions, Chicago, Illinois, USA

In this study we present a 3D multi-slab double-angle method combined with multi-echo CPMG acquisition and compensated catalyzation pulses at the end of each TR which drive the longitudinal magnetization into steady-state enabling short TR for fast large volume RF field mapping.

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Investigating Cancer in Animal Models Using MRI & MRS Room 714 A/B 16:00-18:00 Chairs: Patrick J. Cozzone and Harish Poptani

16:00 363. MR Imaging Based Detection of Glial Brain Tumors in Mice After Anti-Angiogenic Treatment Bob C. Hamans1, An Claes1, Giulio Gambarota1, Olaf van Tellingen2, Pieter Wesseling1, Cathy N. Maass1, Arend Heerschap1, William P.J. Leenders1 1Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands; 2Dutch Cancer Institute, Amsterdam, Netherlands

Use of USPIO as a blood pool contrast agent allows detection of (areas in) tumors that are invisible in conventional Gd-DTPA MRI because of an intact blood brain barrier, such as seen after anti-angiogenic therapy. USPIO imaging may provide more accurate tumor delineation in glioma therapy than conventional Gd-DTPA imaging.

16:12 364. A Proof-Of-Principle Multiparametric in Vivo Study of Tumor Microenvironment Using a MRI Compatible PET Insert Daniel Procissi1, Thomas Sheung Chee Ng1, 2, Xiaowei Zhang1, Yibao Wu3, Ciprian Catana4, Hargun Sohi1, Simon R. Cherry3, Andrew A. Raubitschek5, Russell E. Jacobs1 1California Institute of Technology, Pasadena, California , USA; 2University of Southern California, Los Angeles, California , USA; 3University of California, Davis, Davis, California , USA; 4Massachusetts General Hospital, Boston, Massachusetts, USA; 5City of Hope National Cancer Center, Duarte, California , USA

The ability to assess therapeutic response to cancer treatment is an essential requirement for the development of new types of therapeutic agents. In this perspective both PET and MRI provide unique windows into tumor microenvironment and can potentially probe therapy induced functional and anatomical changes of local tissue. Here we show how it is possible to design and implement an in vivo imaging protocol which allows the simultaneous acquisition of dynamic contrast enhanced (DCE), dynamic 18F-FDG PET and diffusion weighted imaging (DWI) with basic anatomical images using a combined PET/MR scanner.

16:24 365. Why Do Ductal Carcinoma in Situ Lesions Enhance on Dynamic Contrast Enhanced MRI of the Breast? Using X-Ray Fluorescence and MRI to Track the Spatial Distribution of Gd-DTPA in Murine DCIS Sanaz Arkani Jansen1, Tatjana Paunesku, Gayle Woloschak, Stefan Vogt, Suzanne Conzen, Gillian M. Newstead, Gregory Karczmar 1University of Chicago, Chicago, Illinois, USA

Greater sensitivity and specificity of DCEMRI to the preinvasive breast cancer ductal carcinoma in situ (DCIS) is needed. Furthermore, the mechanism for contrast enhancement of DCIS lesions on DCEMRI is not clear. We show that: (i) murine DCIS lesions exhibit contrast uptake in vivo, and (ii) Gd-DTPA can leave blood vessels to enter mammary ducts distended with DCIS. This is a new insight into the mechanism for contrast enhancement of DCIS lesions in DCEMRI. Understanding the uptake of gadolinium in mammary ducts may lead to improvements in imaging methods, mathematical modeling and interpretation of DCEMRI data.

16:36 366. Hypoxia and Elevated Total Choline Are Associated with ‘stem-Like’ Cancer Cells in Breast Cancer Xenograft in Vivo: An MR, SPECT/CT, and Optical Study Balaji Krishnamachary1, Marie-France Penet1, Sridhar Nimmagadda1, Meiyappan Solaiyappan1, Dmitri Artemov1, Kristine Glunde1, Arvind P. Pathak1, Venu Raman1, Martin G. Pomper1, Zaver M. Bhujwalla1 1The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA

The discovery of cancer cells with stem-like markers offers new paradigms for understanding and treating tumor recurrence and metastasis. These stem-like cancer cell populations are more drug resistant and more likely to metastasize. Recent studies suggest that hypoxia provides a suitable niche for stem cells to maintain their precursor status. We have previously shown in a human prostate cancer model that phosphocholine, total choline and choline kinase increase with hypoxia. Here we show in a human breast cancer model that in addition to elevated total choline, the expression of CD44, a breast cancer stem cell marker, increases in hypoxic regions.

16:48 367. Correlation Between Choline Concentration (H-MRS) and Choline Uptake (Cho-PET) and Early Effect of External Radiation Therapy on Both Parameters in an Experimental Tumor Model Denis Jean Rommel1, Frank Peeters1, Jorge Abarca-Quinones1, Nicolas Christian1, Max Lonneux1, Anne Bol1, Daniel Labar1, Vincent Gregoire1, Thierry Duprez1 1Universite Catholique de Louvain, 1200 Brussels, Belgium

We investigated in a rodent tumor model the correlation between choline concentration at 3.0 T H-MRS and the choline uptake at PET. We recorded the early (72 hours) variations of the two parameters after external radiation therapy. No significant pre-therapeutic correlation was found. Opposite evolution after treatment was observed with expected decrease in choline concentration, but strong and paradoxical increase in choline uptake presumptively due to vasodilatation and reactive inflammatory changes.

17:00 368. In Vivo Measurement of Hypoxia in Brain Tumors by QBOLD MRI Methods Joel Richard Garbow1, Sarah C. Jost1, Xiang He1, Dmitriy A. Yablonskiy1 1Washington University in St. Louis, Saint Louis, Missouri, USA

Tumor hypoxia and its downstream effects are of considerable interest in both basic and clinical oncology research due to their negative impact on response to various cancer therapies and promotion of metastasis. Diagnosing tumor hypoxia non-invasively could provide a significant advancement in cancer treatment and will be a key to implementing emerging targeted cancer therapies. Here we report the results of an initial study of hypoxia in a mouse model of high-grade glioma. Our approach to quantifying tumor hypoxia is based on a recently proposed Quantitative Blood Oxygenation Level Dependent (qBOLD) model of BOLD contrast in MRI.

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17:12 369. Comparative Study of Tumor Lactate and Tumor Vasculature in Aggressive and Indolent Prostate Cancer Animal Models by 2D-MR Spectroscopic Imaging and DCE-MRI Jadegoud Yaligar1, Sunitha B. Thakur1, Mihaela E. Lupu1, Ya Wang1, Cornelia C. Matei1, Kristen L. Zakian1, Jason A. Koutcher1 1Memorial Sloan-Kettering Cancer Center, New York, USA

Lactate is marker of tumor malignancy, hypoxia and facilitates progression of malignant disease, there by defy tumor response to radiation and chemotherapy. Aim of this study to compare lactate concentration in aggressive (R3327-AT) and indolent Dunning H (DH) prostate tumor to determine potential of lactate as marker of tumor aggressiveness. Lactate is not detected at low tumor volume and is increased with tumor volume 2200mm3 there after it decreased at 2500mm3 in R3327-AT tumors where as in DH tumors lactate is not detected at low tumor volume-high tumor volume. DCE-MRI parameters are decreased with increased tumor volume in both tumors.

17:24 370. High Spatio-Temporal Resolution PHe Mapping of a Rat Glioma Derived from PH-Dependent Spin-Lattice Relaxivity Xiaomeng Zhang1, Gary V. Martinez2, Maria L. Garcia-Martin3, Mark Woods, Dean Sherry, Robert J. Gillies, 12 1University of Arizona, Tucson, Arizona , USA; 2Arizona Cancer Center, Tucson, Arizona , USA; 3Instituto de Investigaciones Biomedicas, Spain

The extracellular pH (pHe) of cancers is acidic and inhibiting this acidity will inhibit metastases. Methods to image pHe in brain tumors based on relaxivity of a pH-dependent contrast reagent (CR), Gd-DOTA-4AmP were developed. We investigated the single injection of a mixture of DyDOTP with GdDOTA-4AmP. The ¦¤T1, and ¦¤T2* induced by the Gd-CR exhibited similar pH-dependence, while the pH-independent Dy-CR reduced T2* with negligible effects on the T1. Thus, with calibration, co-injection of this cocktail can enable dynamic calculation of spatially localized unique pH values.

17:36 371. Towards In Vivo Brain Tumor Phenotyping with Proton CSI Pattern Perturbation Rui Vasco Simões1, 2, Sebastián Cerdán3, Carles Arús1, 4 1Universitat Autonoma de Barcelona, Cerdanyola del Vallès, Spain; 2Universidade de Coimbra, Coimbra, Portugal; 3Instituto de Investigaciones Biomedicas “Alberto Sols” UAM-CSIC, Madrid, Spain; 4Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Cerdanyola del Vallès, Spain

Here we show that challenging tumor metabolism in vivo (mice bearing a GL261cells brain glioma) by a defined perturbation (hyperglycemia) produces MR spectral pattern changes when monitored by 1H-CSI, which recapitulate those recently described by single-voxel 1H-MRS. This gives us a first insight into brain tumor heterogeneity, as inspected from a dynamic response perspective to a certain metabolic challenge, and suggests a way for increasing the dynamic range of spectral pattern changes of use for improved brain tumor typing and grading.

17:48 372. Imaging the Metastasis of Cancer Cells from a Primary Implant Site Tracey Yik May Lui1, 2, Jonathan Ashchar Snir1, 2, Beth Dun1, 2, Alfred Harvey3, Ron Pettis3, Paula J. Foster1, 2 1Robarts Research Institute, London, Canada; 2University of Western Ontario, London, Canada; 3Becton Dickinson Techonologies, Durham, USA

The lymphatic system is a route in which cancer cells use to metastasize to distant parts of the body. Once cancer cells are found in the lymph nodes a poor patient prognosis is to be expected. Studying the behaviour of cancer cells in the lymphatic system is crucial to prevent/treat metastatic cancer. Using cellular MRI techniques and a unique model involving the implantation of iron-labeled cancer cells directly into the lymph node of a mouse, we show for the first time that cancer cells which have disseminated from the primary tumor can be tracked in-vivo to a distant node.

Case-Based Teaching II: Liver and Pancreatic Tumors Room 716 A/B 16:00 - 18:00 Chairs: Vivian S. Lee and Bernard E. van Beers

16:00 Benign Tumors and Pseudotumors of the Liver Valérie Vilgrain

16:30 Malignant Tumors in the Non-Cirrhotic Liver Claude Sirlin

17:00 Nodules in Liver Cirrhosis

Katsuyoshi Ito 17:30 Tumors of the Pancreas

Thomas Helmberger

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The Aging Brain Room 701 A 16:00-18:00 Chairs: Matilde Inglese and Jeroen van der Grond

16:00 373. Detecting Age-Related Changes in Resting CBF Using Casl MRI Iris Asllani1, Ajna Borogovac, Truman R. Brown, Arjun Kumar, Yaakov Stern 1Columbia University, New York, New York, USA

CBF depression is considered an important correlate of normal aging which could at least partially explain the functional impairment in several processes in elderly. We compared CASL CBF images from young subjects with those from healthy elderly both at voxel- and ROI-wise level. As compared to the young group, the elderly subjects showed a signifiant decrease of ~ 24% in gray matter CBF, in good agreement with data from quantitative PET studies. Furthermore, the areas of CBF depression were consistent with their functional role in normal aging.

16:12 374. Increased Glial Energy Metabolism During Normal Brain Aging Assessed by Dynamic 13C NMR Spectroscopy Fawzi Boumezbeur1, Graeme F. Mason1, Robin A. de Graaf1, Gary W. Cline2, Kevin L. Behar1, Gerald I. Shulman2, 3, Douglas L. Rothman1, Kitt Falk Petersen2 1Magnetic Resonance Research Center, Yale University, New Haven, USA; 2Yale School of Medicine, New Haven, USA; 3Howard Hughes Medical Institute, Yale School of Medicine, New Haven, USA

Age-related alterations in energy metabolism have been implicated as a key factor in many neurodegenerative diseases. In this study, 13C MR spectroscopy was combined with infusions of [1-13C]glucose and [2-13C]acetate to characterize quantitatively neuronal and astrocytic TCA cycle (VTCAn,VTCAa) as well as the glutamate-glutamine cycle (VNT) rates in healthy elderly and young volunteers. Major metabolic changes were measured: 30% increase of VTCAa (p=0.002), a 28% decrease of VTCAn (p=0.013) and a 24% decrease of VNT (p=0.03). Our results demonstrate that alterations in oxidative energy production in neurons and glia form a major characteristic of aging even in healthy elderly subjects.

16:24 375. Alterations of Brain Metabolites During Normal Aging: Correlation with Altered Energy Metabolism Fawzi Boumezbeur1, Robin A. de Graaf1, Graeme F. Mason1, Gary W. Cline2, Kevin L. Behar1, Gerald I. Shulman2, 3, Douglas L. Rothman1, Kitt Falk Petersen2 1Magnetic Resonance Research Center, Yale University, New Haven, USA; 2Yale School of Medicine, New Haven, USA; 3Howard Hughes Medical Institute, Yale School of Medicine, New Haven, USA

For the past few years, many metabolite abnormalities in neurodegenerative diseases have been reported. In this study, we used short TE 1H MR to measure significant age-related changes in NAA (-12%), Glu (-13%) and Ins (+28%) in healthy old people. Further, we correlated the metabolite concentrations with energy synthesis and neurotransmission fluxes (VTCAa, VTCAn and VNT) measured in the same subjects using 13C MRS. Altogether, the results suggest a major evolution of the neuronal-astrocytic metabolic unit with normal aging and support the use of combined 1H and 13C MRS to study the role of brain metabolism in the etiology of neurodegenerative diseases.

16:36 376. Voxel Based Analysis Derived from Fractional Anisotropy Images of White Matter Atrophy with Aging Elisabetta Pagani1, Federica Agosta1, Domenico Caputo2, Massimo Filippi1, 3 1Scientific Institute and University Ospedale San Raffaele, Milan, Italy; 2Scientific Institute Fondazione Don Gnocchi, Milan, Milan, Italy; 3Scientific Institute Fondazione Don Gnocchi, Milan, Italy

In this study, a method to measure WM fiber bundles atrophy using diffusion tensor MRI was used. The age-related changes of the WM volumes from 84 healthy subjects, spanning seven decade of life, were obtained at a voxel-based resolution. A linear correlation was found between age and WM decline in superior-frontal and parietal fibers, anterior cingulum bundles, fornix, and cerebellar peduncles. By contrast, a quadratic regression model best fitted age-related WM loss in the genu of corpus callosum, pons bundles, and inferio-fronto-occipital/uncinate fasciculi. These findings provide evidence that aging of the WM takes different courses and there is considerable variation from region to region in how the effects of age are expressed.

16:48 377. Frontal-Subcortical Pathways for Working Memory: DTI Fiber Pathway Reduction in Healthy Older Subjects Zhihao Li1, Anna Bacon Moore2, 3, Callie Tyner2, Xiaoping Hu1 1Emory Univ./Georgia Tech., Atlanta, Georgia, USA; 2Atlanta VAMC, Atlanta, Georgia, USA; 3Emory Univ., Atlanta, Georgia, USA

In the working memory associated brain network, reduction of structural connectivity is non-uniform with advancing age. This may be part of the neurobiological basis of the HAROLD (Hemispheric Asymmetry Reduction in Older Adults) effect.

17:00 378. Correlation of Fractional Anisotropy in Rhesus Monkeys with Age and Motor Function Peter Andrew Hardy1, David Kennedy Powell1, Zhiming Zhang1 1University of Kentucky, Lexington, USA

Diffusion Tensor Imaging and Fractional Anisotropy analysis was used to correlate changes with age and with motor function in a cohort of healthy rhesus monkeys.

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17:12 379. Ageing and Fractional Anisotropy: Global and Regional Results Ramtilak Gattu1, Randall R. Benson2, 3, Balaji Myrtheunjayan1, Kristen Kennedy2, Naftaki Raz2, Zhifeng Kou4, Ewart M. Haacke5 1Wayne State University, Detroit, USA; 2Wayne State University School of Medicine, Detroit, USA; 3Detroit Medical Center, Detroit, USA; 4Wayne State University School of Medicine, Detroit, Michigan, USA; 5wayne state university, Detroit, USA

Few DTI studies demonstrated the age effect on fractional anisotropy (FA). We examined the effect of age on FA for whole brain white matter and in corpus callosum (CC). 70 healthy volunteers (aged 19-81, SD= 19.22 years) were imaged with DTI on a 1.5T scanner. All three regions of CC (genu, body, and Splenium) showed a slight decline in FA with age, with the greatest age effect in genu. This equates to a drop of .006 per decade. We also found a trend towards greater variance in FA with age suggesting a heterogeneous adverse effect of ageing on WM fibers.

17:24 380. Different T1 Relaxation Brain Ageing Patterns Over the Human Lifespan: Frontal vs. Posterior Brain (75 Subjects) Naoko Saito1, Hernan Jara1, Osamu Sakai1 1Boston Medical Center, Boston University School of Medicine, Boston, Massachusetts, USA

Purpose: To evaluate the regional T1 changes over the human lifespan with quantitative MR imaging (Q-MRI). Methods: 75 subjects (0.5-87 years) obtained with the mixed-TSE pulse sequence were segmented into six segments: bilateral frontal, bilateral posterior and bilateral cerebellar segments leading to six T1 histograms per subject. Results: For all ages studied, T1 of frontal GM was consistently and bilaterally longer than T1 of posterior GM, by about 10%. Conclusion: T1 relaxation mechanisms in frontal GM are weaker than in posterior GM over the full human lifespan suggesting different frontal vs. posterior tissue micro-architecture and/or hydration level.

17:36 381. Alterations of Globus Pallidus Magnetisation Transfer Ratio, T1, T2 in Primary Biliary Cirrhosis Patients and Controls: Relationship with Age and Autonomic Dysfunction Kieren Grant Hollingsworth1, Julia L. Newton1, Benjamin S. Aribisala1, Peter Edward Thelwall1, Roy Taylor1, Andrew M. Blamire1, David E. Jones1 1Newcastle University, Newcastle Upon Tyne, UK

Primary Biliary Cirrhosis is an autoimmune liver disease resulting in debilitating fatigue for 50% of affected patients. One hypothesis postulates that the fatigue may originate from metal deposition in the globus pallidus (GP), measurable in the magnetization transfer ratio (MTR), but normal ageing effects have not been taken into account to date. This study investigated an age-matched group of 30 early-stage patients and 14 volunteers, assessing GP MTR, T1 and T2. The same age-related trend was found in patients and controls and GP T2 correlated with measures of autonomic dysfunction.

17:48 382. The Impact of Cerebrovascular Risk Factors on Brain Tissue Changes: A MTI Study Stefan Ropele1, Christian Enzinger1, Gernot Reishofer1, Reinhold Schmidt1, Franz Fazekas1 1Medical University Graz, Graz, Austria

The study goal was to explore if specific cerebrovascular risk factors may have an impact on the cerebral tissue matrix as assessed by the magnetization transfer ratio (MTR). Measurement of the MTR was done in white matter hyperintensities and in normal appearing brain tissue (NABT) of 328 neurologically asymptomatic elderly subjects. A multivariate regression model was used to study the effect of a large battery of possible risk factors on global and lesional MTR changes. Our results suggest that MTR changes in NABT are related predominantly to the ageing process per se. Diabetes and hypertension may exert some additional minor effects.

Quantitative Flow Imaging Room 701 B 16:00-18:00 Chairs: Michael Markl and Krishna S. Nayak

16:00 383. Assessment of Stroke Volume Variability Using Real-Time Spiral Phase Contrast Joao Luiz Azevedo de Carvalho1, Hervaldo Sampaio Carvalho2, Krishna S. Nayak1 1University of Southern California, Los Angeles, California , USA; 2University of Brasilia, Brasilia, Brazil

Stroke volume variability provides information about the activity of the autonomic nervous system, connecting heart rate variability to blood pressure and venous return variabilities. There is currently no non-invasive gold-standard for measuring stroke volume. Recent MR methods can measure cardiac output by integrating flow volume through several cardiac cycles. We propose a method that is capable of measuring changes in stroke volume on a beat-to-beat basis, using real-time spiral phase contrast. We present and discuss measured dynamic changes in stroke volume during stimuli such as the Valsalva maneuver, handgrip, facial cooling, mental stress and cold pressor.

16:12 384. Real-Time and Cardiac Gated CINE MR Doppler Juan Manuel Santos1, Adam B. Kerr1, Daeho Lee1, Michael V. McConnell1, Phillip C. Yang1, Bob S. Hu2, John M. Pauly1 1Stanford University, Stanford, USA; 2Palo Alto Medical Foundation, Palo Alto, USA

The examination of valvular heart disease includes the assessment of valvular morphology, cardiac output, intracardiac pressures, ventricular volume and volume regurgitations. Magnetic resonance imaging (MRI) is potentially the most appropriate technique for addressing all of these areas in a single examination. We have previously implemented an MRI subsystem that seamlessly integrates most of the capabilities needed for a comprehensive valve evaluation. In this work, we have expanded this system to include a cardiac gated CINE MR Doppler sequence to improve the resolution and velocity range of our previously demonstrated Real-Time MR Doppler sequence.

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16:24 385. Reference-Less Flow Measurements Using Refocused SSFP Jon-Fredrik Nielsen1, Krishna S. Nayak1 1University of Southern California, Los Angeles, California , USA

Phase-contrast (PC) MRI is an established flow quantitation technique, but suffers from limited spatio-temporal resolution, and inferior SNR compared to balanced SSFP sequences. Recently, several groups have proposed PC-MRI methods based on SSFP, which achieve accurate flow quantitation with high SNR efficiency. However, the total acquisition time for any phase-contrast-based method is intrinsically high, since one or more separate phase reference scans must be acquired. We propose a flow quantitation approach that exploits the intrinsic refocusing property of SSFP, to achieve 50% reductions in scan time.

16:36 386. Accelerated Phase-Contrast MR Imaging: Comparison of SENSE, K-T BLAST and Doppler Ultrasound for Velocity and Flow Measurements of the Aorta Andreas Stadlbauer1, Wilma van der Riet2, Sebastian Globits3, Gerard Crelier4, Erich Salomonowitz1 1Landesklinikum St.Poelten, St. Poelten, Austria; 2European MRI Consultancy (EMRIC), Strasbourg, France; 3Landesklinikum St. Poelten, St. Poelten, Austria; 4GyroTools, Zurich, Switzerland

To evaluate differences in aortic velocity and flow measurements between accelerated phase-contrast MRI using SENSE and k-t BLAST, and were correlated to continuous wave (CW) Doppler. 2D PC-MRI was performed using SENSE (R=2) and k-t BLAST (2-, 4-, 6-, and 8-fold). Peak and mean velocity, and stroke volume of accelerated PC-MRIs were compared. Strong correlations between SENSE and k-t BLAST were found for all parameters. Significant differences between SENSE and 4-, 6-, and 8-fold k-t BLAST were found in peak velocity and stroke volume. Peak velocities was underestimated by PC-MRI but correlated significant with CW-Doppler.

16:48 387. Improved Velocity-To-Noise Ratio in Time-Resolved 3D Blood Flow Measurements for Cardiac Imaging Jochen von Spiczak1, Robert Manka1, Gérard Crelier1, Peter Boesiger1, Sebastian Kozerke1 1University and ETH Zurich, Zurich, Switzerland

Time-resolved phase-contrast imaging permits the assessment of volumetric, multi-directional blood flow velocities. The objective of this work was to improve the velocity-to-noise ratio by lowering the encoding velocity in conjunction with an automatic phase unwrapping algorithm suited for time-resolved 3D blood flow measurements. The gain in VNR was used to compensate for SNR loss in accelerated scans using parallel imaging and concurrently increase spatial resolution. Comparing relative VNR of the normal and accelerated acquisitions resulted in a factor close to the theoretical prediction. A patient with a dilated ascending aorta was scanned demonstrating the feasibility of such technique.

17:00 388. MRI Determination of Pulse Wave Velocity in the Carotid Arteries Christopher J. Hardy1, Luca Marinelli1, Daniel J. Blezek1, Robert D. Darrow1 1GE Global Research, Niskayuna, New York, USA

Fourier-velocity-encoded M-mode MRI provides a fast, non-invasive measure of pulse wave velocity, and thus arterial distensibility. In this technique, a movie of blood velocity distributions is generated, in which the velocity wave can be seen propogating along the artery. Several improvements have been made to this technique to allow its use in shorter segments of smaller vessels, such as the carotid arteries. A new analysis method has been developed for more accurate semi-automated calculation of PWV. Pencil excitation pulses employing more spiral turns and using stronger gradients have also been developed to reduce pencil diameters to 5 mm.

17:12 389. Aortic Pulse Wave Velocity Assessed with Velocity-Encoded MRI: Validation with Catheterization and Clinical Applicability Jos J.M. Westenberg1, Heynric B. Grotenhuis1, Paul Steendijk1, Dennis Hendriksen1, Theodorus A.M. Kaandorp1, Rob J. van der Geest1, J. W. Jukema1, Jeroen J. Bax1, Johan H.C. Reiber1, Albert de Roos1 1Leiden University Medical Center, Leiden, Netherlands

Aortic Pulse Wave Velocity (PWV), a surrogate marker for arterial wall compliance, is assessed non-invasively with Velocity-Encoded MRI and compared with invasive pressure measurements during catheterization. Reproducibility as well as physiological variation in PWV is tested and clinically applied to define cut-off values for discriminating coronary disease.

17:24 390. Hemodynamics and Wall Shear Stress in the Pulmonary Arteries of Hypertension Patients Using Phase Contrast MRI Alex J. Barker1, Craig Lanning2, Robin Shandas, 12 1University of Colorado, Boulder, Colorado , USA; 2The Children's Hospital, Denver, Colorado , USA

Pulmonary arterial hypertension (PAH) is an important determinant of morbidity and mortality in children with congenital heart disease. In order to further understand this complex disease, and, since hemodynamic factors are known pathophysiological stimuli in the production of molecules that alter vascular tone and matrix properties, this study attempted to quantify these effects in the proximal left, right and main pulmonary arteries (LPA, RPA, & MPA) of control and hypertensive patients using phase-contrast magnetic resonance imaging (PC-MRI). Preliminary results show that PAH patients demonstrate a marked difference in both their flow pulse and WSS waveforms when compared to normotensive patients.

17:36 391. Temporal Stability of the Background Velocity Error Supports Automated Correction of Flow Measurements Peter D. Gatehouse1, Ajmal Nafisa, Philip J. Kilner, David N. Firmin 1Royal Brompton Hospital, London, UK

Background errors even smaller than 1% of the VENC can seriously affect measurements of regurgitant fraction and shunt flow. This abstract investigates the feasibility of using stored background error corrections acquired once in a set of relevant planes and sequence parameters. This approach assumes that the background offset error is stable with time. In the absence of any published data on this stability, we tested it over 40 days and found that the background is stable enough to support this approach.

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17:48 392. Magnetic Field Monitoring for Improved Phase Contrast Flow Quantification Florian Wiesinger1, Silke Maria Lechner1, 2, Pekka Sipilae1, 2, Thomas K. Foo3 1GE Global Research, Munich, Germany; 2Munich University of Technology, Munich, Germany; 3GE Global Research, Niskayuna, New York, USA

Phase contrast (PC) based flow quantification is prone to magnetic field imperfections caused by Eddy currents and concomitant fields. This problem is known to result in inaccurate quantification of volume flow rates, with the potential implication of misleading diagnosis. In this work, a novel correction technique is presented based on magnetic field monitoring (MFM). Dedicated magnetic field sensors are utilized to measure the actual magnetic fields during the execution of the pulse sequence. Phantom results indicate a significant improvement of PC-based flow quantification using MFM.

Lung Structure & Function Room 713 A/B 16:00-18:00 Chairs: Sean B. Fain and Samuel Patz

16:00 393. Young Investigator Award Finalist: Hyperpolarized 3He Diffusion MRI at Two Time Scales During a Single Breath Hold: Assessment of the Lung Microstructure in Asthmatics with Comparison to Healthy and COPD Subjects

Chengbo Wang1, Talissa A. Altes1, 2, John P. Mugler, III2, G. Wilson Miller2, Kai Ruppert1, 2, Jaime F. Mata2, Gordon D. Cates, Jr2, Larry Borish2, Eduard E. de Lange2 1Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA; 2University of Virginia, Charlottesville, Virginia , USA

Co-registered short-time-scale and long-time-scale hyperpolarized 3He ADC maps were collected in 14 healthy, 14 asthma and 9 COPD subjects. Compared to the healthy group, the short-time-scale and long-time-scale mean ADC was increased by 9% and 27% (p=0.038 and 0.005) in asthmatics, respectively, and 71% and 117% (p=0.002 and p<0.001) in subjects with COPD, respectively. Regional changes on long-time-scale ADC maps were more conspicuous and more extensive than on short-time-scale ADC maps. Thus, diffusion abnormalities are present in asthmatics, and the long-time-scale ADC appears to have an increased regional sensitivity to these abnormalities.

16:20 394. In Vivo Lung Morphometry Identifies Detail Changes of Lung Microstructure with Emphysema Progression Dmitriy A. Yablonskiy1, Alex L. Sukstanskii1, Jason C. Woods, Andrew J. Bierhals1, Yulin V. Chang, Richard E. Jacob, Mark S. Conradi, David S. Gierada1 1Mallinckrodt Institute of Radiology, St. Louis, Missouri, USA

Numerous measurements of hyperpolarized 3He gas ADC in human lungs indicated substantial changes between healthy and emphysematous lungs. Herein we use the in vivo lung morphometry technique, based on MRI measurement of diffusion of hyperpolarized 3He gas, to identify changes in lung microstructure with emphysema progression. We demonstrate that at the initial stages of emphysema, walls separating alveoli belonging to the same acinar airways are getting destroyed by the disease without substantial effect on inter-airway walls. This follows by destruction of inter-airway walls. We conclude that the In vivo lung morphometry allows non-invasive monitoring emphysema progression at the alveolar level.

16:32 395. Self-Calibrated Voxel-Wise Assessment of Ventilation During Respiration Using Dynamic Hyperpolarized 3He MRI Davide Santoro1, Abram Voorhees2, Vinay Pai1, Igor Kamenetskiy1, Jean Reid1, Glyn Johnson1 1New York University School of Medicine, New York, USA; 2Siemens Medical Solutions, Inc., Malvern, USA

In this work, a novel method for tracking regional lung motion is applied to provide the local air volume and volumetric flow rate on a voxel scale. The method is based on motion-tracking of the lungs over a series of real-time, hyperpolarized 3He images.

16:44 396. Determination of Alveolar Oxygen Partial Pressure in Rat Lung Using Spin-Spin Relaxation Times of 3He and 129Xe at Low Magnetic Field Strength Ryan Kraayvanger1, 2, Chris Bidinosti3, William Dominguez-Viqueria1, 2, Juan Parra-Robles2, Matthew Fox1, 2, Wilfred Lam2, Giles Santyr, 12 1University of Western Ontario, London, Canada; 2Robarts Research Institute, London, Canada; 3University of Winnipeg, Winnipeg, Canada

Quantitative assessment of alveolar oxygen partial pressure (pAO2) in the lung has the potential to become a remarkably useful tool in the diagnosis and monitoring of respiratory disease. It has been demonstrated that pAO2 can be measured using the spin-spin relaxation time, T2, of 3He at very low magnetic field strengths with the Carr-Purcell-Meiboom-Gill (CPMG) sequence. We present relaxivity relationships for oxygen’s effect on 3He and 129Xe spin-spin relaxation, in vivo T2 measurements in rat lung, and test the assertion that T2=T1 in the limit of rapid CPMG pulse rates at low magnetic field strength.

16:56 397. Detection of Perfusion-Induced Susceptibility Effect in the Lung by Hyperpolarized 3He MRI: A Co-Registration with Partial Pressure of Oxygen Jiangsheng Yu1, Michelle Law1, Kiarash Emami1, Sheeva Rajaei1, Masaru Ishii, 12, Stephen Kadlecek1, Vahid Vadhat1, John MacDuffie Woodburn1, Richard A. Guyer1, Hans Hyonchang Kim1, Warren Gefter1, Rahim R. Rizi1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA; 2Johns Hopkins University, Baltimore, Maryland, USA

Hyperpolarized 3He MRI has focused primarily on structural and functional aspects of the airspaces. In this work, we present a double-echo acquisition technique for measuring perfusion-induced susceptibility effect. This technique allows automatic co-registration of lung perfusion and ventilation images. In the in-vivo animal experiment, a normal Yorkshire pig (~20kg) was injected with 10mL gadolinium to modify the magnetic susceptibility difference between the lung airway and capillary bed. A susceptibility measurement was performed 10 minutes after the Gd injection. The average phase change caused by this susceptibility difference enhancement (Gd injection) was 57 degrees; while the global mean values of pO2 and R were not affected by the Gd injection.

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17:08 398. Quantitative Analysis of MCh Induced Ventilation Changes in Mouse Lungs in a Time Series Nilesh Navnitlal Mistry1, 2, Bastiaan Driehuys2, Boma Fubara2, William M. Foster2, Erin N. Potts2, Ben Chen3, Deborah M. Slipetz3, G. Allan Johnson2 1Duke University, Durham, North Carolina, USA; 2Duke University Medical Center, Durham, North Carolina, USA; 3Merck Frosst Center for Therapeutic Research, Montreal, Canada

Recent high-resolution 3He MRI in mouse models of asthma have provided an opportunity to understand airway biology by depicting regional ventilation changes, and airway narrowing and closure. To maximize the value of 3He MRI, it is important to quantify these ventilation changes visible in the images. In this work, we describe a post-processing scheme to quantify regional ventilation changes before and after MCh challenge; and show that it is sensitive to both changes in airway caliber and subtle regional alterations in ventilation.

17:20 399. ENaC-Mediated Effects Assessed by Proton MRI in a Rat Model of Hypertonic Saline-Induced Hydration of Airways François-Xavier Blé1, 2, Stefan Zurbruegg1, Steve Collingwood3, Henry Danahay3, Nicolau Beckmann1 1Novartis Institutes for BioMedical Research, Basel, Switzerland; 2University Louis Pasteur-Strasbourg-1, Illkirch, France; 3Novartis Institutes for BioMedical Research, Horsham, UK

Nebulized hypertonic saline (HS) provides benefit to cystic fibrosis patients. Since the effects of HS are transient, administration of epithelial sodium channel (ENaC) blockers prior to HS is being pursued as strategy to improve the duration of action of HS. Using MRI we followed the fluid dynamics in the lungs of spontaneously breathing rats treated with compounds that interacted with ENaC, administered before HS. As a non-invasive readout of global fluid dynamics in the whole lung in situ, MRI provides complementary information to that obtained using in vitro or ex vivo models currently supporting ENaC-related drug investigations.

17:32 400. Multi-Center Study for Clinical Stage Classification of Smoking-Related COPD: Oxygen-Enhanced MRI vs. Quantitatively Assessed MDCT Yoshiharu Ohno1, Tae Iwasawa2, Joom Beom Seo3, Hisanobu Koyama1, Hiroshi Takahashi2, Yeon-Mok Oh3, Yoshihiro Nishimura4, Kazuro Sugimura1 1Kobe University Graduate School of Medicine, Kobe, Japan; 2Kanagawa Cardiovascular and Respiratory Center, Yokohama, Japan; 3University of Ulsan College of Medicine, Seoul, Republic of Korea; 4Kobe University Graduate School of Mediciine, Kobe, Japan

O2-enhanced MRI as well as hyperpolarized noble gas MR imaging have been proposed as useful procedures for evaluation of morphological changes or regional pulmonary functional changes. However, the literature shows no publications dealing with prospective and direct comparison of the capability of quantitatively assessed CT (quantitative CT) and of O2-enhanced MRI for smoking-related functional loss assessment and clinical stage classification of smoking-related COPD. The purpose of the multi-center trial conducted for this purpose was to prospectively and directly compare the efficacy of O2-enhanced MRI and quantitative CT for smoking-related pulmonary functional loss assessment and clinical stage classification of smoking-related COPD.

17:44 401. Increased Pulmonary Capillary Permeability in Smokers as Measured by DCE-MRI Josephine Helen Naish1, Deirdre M. McGrath1, Charles E. Hutchinson1, Lars E. Olsson2, John C. Waterton, 13, Chris J. Taylor1, Geoff J. Parker1 1University of Manchester, Manchester, UK; 2AstraZeneca, Mölndal, Sweden; 3AstraZeneca, Macclesfield, UK

In this study we demonstrate the feasibility of measuring regional pulmonary vascular endothelial permeability using DCE-MRI. By acquiring and modelling an extended dynamic time series we observe significantly increased vascular permeability in a group of smokers compared with a group of non-smokers. This observation is consistent with the presence of smoking-induced inflammation.

MR Physics and Techniques for Clinicians Hall F 16:00 - 18:00 Chairs: Frank R. Korosec and Joseph C. McGowan

Educational Objectives: Upon completion of this session, participants should be able to:

• Define and describe the fundamental principles of MR imaging, including the definition of spin magnetization, the Larmor relationship, relaxation phenomena, and the process of using the spin magnetization to produce an image;

• Explain imaging pulse sequences based upon spin and gradient echoes, including fast spin echo and echo planar techniques; • Design MR imaging protocols for diagnostic applications considering image contrast, spatial resolution, acquisition time, signal-to-noise ratio,

and artifacts; and • Describe the principles of parallel imaging, fat and water imaging, and diffusion imaging.

16:00 Spin Echo Imaging R. Scott Hinks 16:40 Gradient Echo Imaging Michael Markl 17:20 Fast Spin Echo Imaging Joseph C. McGowan

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Non-BOLD of Multi-Modal fMRI Hall G 16:00-18:00 Chairs: Jacco A. de Zwart and John C. Gore

16:00 402. Detecting Brain Activity Using Direct Water Saturation Manus Joseph Donahue1, 2, Jun Hua1, 2, Richard Anthony Edden, 13, Seth A. Smith1, 2, Peter van Zijl1, 2 1The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA; 2The Kennedy Krieger Institute, Baltimore, Maryland, USA; 3Cardiff University, Cardiff, UK

During increased brain activity, magnetic susceptibility changes in parenchyma, which will lead to increases in parenchymal T2 and a more narrow saturation line shape. We show that when a direct saturation pulse is applied at the correct frequency offset, short duration and low power, the MR signal increases (1.3±0.2%) during elevated brain activity, which we attribute to a narrowing in the saturation line shape of parenchyma consequential to neuronal activation. The results provide the basis for a new, short-TE spin echo approach for performing fMRI based on direct water saturation.

16:12 403. Estimation of Vascular Contribution to DfMRI (Diffusion Weighted FMRI) Signal Shin-ichi Urayama1, Kenji Aso1, Toshihiko Aso2, Satoru Kohno1, Nobukatsu Sawamoto1, Hidenao Fukuyama1, Denis Le Bihan2 1Kyoto Univ., Kyoto, Japan; 2CEA, France

To investigate vascular contribution to DfMRI (Diffusion weighted fMRI) signal, responses to visual stimulation and hypercapnia challenge were monitored and analyzed on an individual subject basis. Although the % signal changes of DfMRI and BOLD responses were not significantly different with the visual stimulation, the response is much larger with BOLD than DfMRI during CO2 inhalation. This results show that at least half of the DfMRI signal is not explained by vascular sources.

16:24 404. Functional MRI in White Matter: Experimental Evidence at 4-T Erin Mazerolle1, Xiaowei Song1, Kimberly Brewer1, Steven Beyea2, Ryan D'Arcy1 1National Research Council, Halifax , Canada; 2National Research Council, Halifax, Canada

Functional MRI activity is believed to be restricted to gray matter. White matter (WM) activation is controversial. Due to the relative reduction of blood flow/volume and the drop in reliance on synaptic transmission, it is often thought to be an artifact. Despite this, an increasing number of studies are reporting WM activation. The current study evaluated this notion using an established neurological model for interhemispheric transfer of visual/motor information across the corpus callosum. The results revealed activation in callosal regions consistent with visual/motor transfer. The findings highlight the importance of investigating the potential for fMRI in WM.

16:36 405. Neuronal Current Imaging: Sensitivity of Magnitude and Spatial Distribution to Changes in Current Timing Ivana Drobnjak1, Gaby Pell, Mark Jenkinson 1University of Oxford, Oxford, UK

Direct neuronal current imaging is a method that could potentially provide direct access to neuronal activity with an excellent spatial (mm) and temporal resolution (ms). However, so far it has not been convincingly demonstrated that MRI has adequate sensitivity to detect neuronal currents in vivo. In order to pin down the most influential factors in the signal formation, with the goal of eventually optimizing them for the MR detectable signal change, Pell et al. used a simple conducting wire model with various scanning and field parameters to investigate signal magnitude changes. The experimental results indicate not only significant changes in signal magnitude but also in spatial pattern. Specifically, the current can create a very localized Gibbs ringing in the image. We show both experimentally and analytically that the timing of the current within the pulse sequence completely determines the width and the magnitude of the ringing. Since currently we are on the limit of neuronal-current MR sensitivity, this is a significant finding as it can help us both tune the parameters of the acquisition to achieve maximal sensitivity as well as understand the effects of arbitrary neuronal currents on the MR signals.

16:48 406. Magnetization “reset” for Non-Steady-State Blood Spins in Vascular-Space-Occupancy (VASO) FMRI Hanzhang Lu1 1University of Texas Southwestern Medical Center, Dallas, USA

VASO is a technique targeting for CBV based fMRI. However, recent evidences have suggested that the mechanism of VASO signal may contain contributions from flow-related effects due to non-steady-state blood spins. We aim to eliminate non-steady-state spins and “reset” the magnetization by adding a non-slice-selective 90º saturation RF pulse immediately after the image acquisition (post-sat). Experiments and numerical simulations showed that the post-sat pulse can eliminate virtually all fresh spins and bring the VASO signal back to a level consistent with predominantly CBV-contrast for a TR range of 1-1.6s. At intermediate TR range, the post-sat also reduced the flow contributions.

17:00 407. Combine NIRS and Fmri to Investigate Hemodynamic Response to Transient Activation and Deactivation Lin Tang1, Malcolm J. Avison1, John C. Gore1 1Vanderbilt University Institute of Imaging Science, Nashville, Tennessee, USA

We used transcranial near-infrared spectroscopy (NIRS) and fMRI at 3T to investigate both positive and negative BOLD effects. Using NIRS we recorded concentration changes in both oxy- and deoxy- as well as total hemoglobin levels by measuring changes of absorption at two different wavelengths in brain in response to both transient activations and deactivations. Similar experiments were also performed using fMRI. In addition to previous observed different nonlinearity of BOLD responses to activation and deactivation, we also compared BOLD and NIRS measurements during various stimulation paradigms and tried to explain the mechanism of the observed BOLD.

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17:12 408. Functional Mapping of CK and ATPase Metabolic Rate Changes Elevated by Visual Stimulation in Cat Brain Xiao-Hong Zhu1, Yi Zhang1, Wei Chen1 1Center for Magnetic Resonance Research, Minneapolis, Minnesota, USA

In vivo 31P MRS combined with magnetization saturation transfer (MT) method has been recently demonstrated to be capable of noninvasively measuring the Cerebral Metabolic Rate of the CK enzyme reaction (CMRCK) and ATPase enzyme reaction (CMRATP) simultaneously in living brains. We have also demonstrated that both CMRCK and CMRATP are tightly coupled with varied brain activity in the resting brain. In this study, we have applied the in vivo 31P MT approach to address the question whether CMRCK or CMRATP changes in the cat visual cortex during visual stimulation. Our results show: i) both CMRCK and CMRATP increased significantly in the activated visual cortex with relative less extent for CMRCK; ii) the feasibility for obtaining 3D functional metabolic CK rate maps in the cat brain; and iii) a similar percentage changes of the elevated CMRATP and CMRO2. These findings indicate a tight coupling between the oxygen utilization and oxidative phosphorylation during stimulation and the essential roles of oxidative phosphorylation in brain bioenergetics associated with brain function and activation.

17:24 409. Metabolic Imprint of EEG Slow Oscillations as Observed by BOLD-FMRI During Deep Sleep Silvina G. Horovitz1, Masaki Fukunaga1, Dante Picchioni2, Walter S. Carr3, Jacco A. de Zwart1, Thomas J. Balkin2, Allen Braun4, Jeff H. Duyn1 1NINDS , NIH, Bethesda, Maryland, USA; 2Walter Reed Army Institute of Research, Silver Spring, Maryland, USA; 3Naval Medical Research Center, Silver Spring, Maryland, USA; 4NIDCD, NIH, Bethesda, Maryland, USA

EEG slow oscillations have been suggested to facilitate the beneficial effects of sleep on learning. Here, we investigated the metabolic imprint of these oscillations by performing concurrent EEG and BOLD fMRI during sleep in normal volunteers. The results confirm earlier observations from electrophysiology that associate thalamic and sensory areas with the phenomenon of EEG slow oscillations.

17:36 410. The Relationship Between FMRI and MEG: Visual Contrast Response Claire Stevenson1, Matthew Brookes1, Peter Morris1 1The University of Nottingham, Nottingham, UK

A combination of fMRI and MEG may provide insight into the neuronal basis of the BOLD effect. Here, we investigate the correlation and linearity of evoked and induced MEG signals and the BOLD response elicited by visual stimuli of varying contrasts. This experiment allows spatial separation of the evoked, beta and gamma MEG responses and provides a method of determining the extent to which each of the individual responses contribute to the BOLD response. The excellent co-localisation of the MEG and BOLD data suggests that the two are intimately linked.

17:48 411. An FMRI and MEG Investigation of Repetition Suppression in the Visual Cortex Rishma Vidyasagar1, Andrej Stancak2, Laura M. Parkes1 1MARIARC , University of Liverpool, Liverpool, UK; 2School of Psychology, University of Liverpool, UK

This study investigates the phenomenon of repetition suppression in the visual cortex using behavioural, fMRI and MEG data. 9 subjects were tested with the same paradigm using all three modalities and data were analysed according to specific visual areas. Significant suppression of BOLD and MEG responses were observed in V2/V3 areas when paired stimuli with the same characteristics were presented at an interstimulus interval (ISI) of 200 msec, compared to paired stimuli of different characteristics at the same ISI. This study uses the data in an attempt to explain the reasoning behind repetition suppression using previously proposed models.

BRONZE CORPORATE MEMBER SYMPOSIUM Bayer Healthcare MRI Contrast Media – Challenges & Opportunities Room 718 A 18:15 – 19:45

BRONZE CORPORATE MEMBER SYMPOSIUM Bracco Contrast Enhancement in MR Imaging: Issues & Answers Room 701 B 18:15 – 19:45

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MORNING CATEGORICAL COURSE Safety Update Room 801 A/B 7:00 – 8:00 Chair: Penny A. Gowland

Educational Objectives: Upon completion of this course, participants should be able to:

• List the main interactions between the statis field and the sensory organs in humans; • List the main interactions between the static field and cells; • Explain the origins of the inhomogeneous temperature rise in the body due to exposure to the RF field from an MRI RF coil, and predict

situations likely to lead to an increased risk of RF burns; • Decide how to recommend whether it is safe to scan someone with an implant; • Identify the hazards associated with MR contrast agents, and contrast different types of agents in terms of the risk profiles; and; • Compare the regulatory position for MRI across the world.

07:00 RF Heating: RF Modelling – Hot Spots and Blood Flow Tamer S. Ibrahim 07:30 RF Heating: RF and Implants John A. Nyenhuis

MORNING CATEGORICAL COURSE Ultra-High Field MR in Humans Room 718 A 7:00 – 8:00 Chairs: Klaas Pruessmann and Lawrence L. Wald

Educational Objectives: Upon completion of this course, participants should be able to:

• Explain the importance of array technology for RF excitation and detection at ultra-high field, along with its basic modes of operation; • Distinguish different types of BOLD contrast in ultra-high-field fMRI and describe corresponding pulse sequences; • Name the key problems and their current solutions in ultra-high-field MRS; • List promising applications of ultra-high-field MR in and outside the brain and name their remaining limitations.

07:00 Leveraging Ultra-High Field for BOLD fMRI Essa Yacoub 07:30 Addressing B0 Inhomogeneity in Ultra-High Field fMRI Oliver Speck

MORNING CATEGORICAL COURSE Absolute Beginners’ Guide to Anatomical and Functional MRI of the Human Brain Room 718 B 7:00 – 8:00 Chairs: Alan Connelly and Chloe Hutton

Educational Objectives: Upon completion of this course, participants should be able to:

• Identify the neuroanatomical and neurophysiological parameters which are accessible to MR measurement; • Describe the underlying physics of MR neuroimaging techniques; • Describe the data acquisition and analysis techniques most commonly used for anatomical and functional MRI of the brain; and • Recognize the potential value of advances such as parallel imaging, fast imaging techniques and high magnetic field strengths for imaging the

brain. 07:00 Absolute Beginner’s Guide to Diffusion MRI Derek K. Jones

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MORNING CATEGORICAL COURSE Clinical Science for Physicists and Engineers Room 714 A/B 7:00 – 8:00 Chairs: Vivian S. Lee, Tim Leiner, and Bachir Taouli

Educational Objectives: Upon completion of this course, participants should be able to:

• Identify basic anatomy and physiology of the central nervous system, kidney, liver, cardiac, vascular and musculoskeletal systems; • Describe the process and diagnosis of stroke and white matter formation and damage; • Explain kidney and liver anatomy and function, and how MRI can be used to evaluate these organs; • Discuss basic cardiac physiology and the consequences of coronary artery disease and heart failure; • Describe the process of bone and cartilage formation and degeneration; and • Appraise unmet clinical needs that could potentially be solved by physicists and engineers.

Body: Anatomy, Function, Pathology, and Challenges 07:00 Liver function and Failure Bachir Taouli 07:30 Kidney Function and Failure Vivian S. Lee

MORNING CATEGORICAL COURSE Body MRI by the Experts II: Lung fMRI and Multi-Parametric Prostate MR Room 716 A/B 7:00 – 8:00 Chairs: Qun Chen, Clare Tempany, and Bernard E. Van Beers

Educational Objectives: Upon completion of this course, participants should be able to:

• Describe the impact of functional, quantitative and molecular MR in abdominal imaging; • Apply new body MR techniques in their practice; • Use Multiparametric MRI for improved diagnosis of abdominal diseases; • Describe indications of functional and quantitative MRI in the assessment of liver, pancreas, bowel, and kidney diseases; • Design new female pelvic and prostate protocols, introducing these methods and compare them to more conventional approaches; and • Appraise the indications for anatomical and functional imaging of the breast and the lungs.

Multi-Parametric Prostate MRI, Clare Tempany, Moderator 07:00 Multi-Parametric MR Fergus Coakley 07:30 Prostate MR 3T or 1.5T in the Clinic Jurgen Fütterer

MORNING CATEGORICAL COURSE Neuroimaging: What can clinicians learn from the animal model work? Room 701 A 7:00 – 8:00 Chairs: Pia C. Maly Sundgren and Annemie van der Linden

Educational Objectives: Upon completion of this course, participants should be able to:

• Describe the main MRI methods used in experimental studies to diagnose 1) Amyotrophic Lateral Sclerosis (ALS), 2) Stroke, and 3) Cerebral Amyloid Angiopathy (CAA), and the underlying rationale;

• Explain what is known about the underlying mechanism in ALS, stroke, and CAA and which type of MRI investigations could be used for (early) diagnosis of these diseases;

• List the main MRI methods used in the clinical setting to diagnose these diseases and the underlying principles behind them; and • Make the translate from what is – and can be – done in experimental studies on ALS, stroke, and CAA to what can be done clinically.

07:00 Focus on Stroke: Determining the Outcome/Prognosis through Experimental Work Tracy D. Farr

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07:25 Focus on Stroke: Determining the Outcome/Prognosis in the Clinic Susanne Wegener 07:50 Discussion

MORNING CATEGORICAL COURSE Clinical Application of Cardiovascular Imaging Room 701 B 7:00 – 8:00 Chairs: Georg Bongartz and Stefan G. Ruehm

Educational Objectives: Upon completion of this course, participants should be able to:

• Describe state-of-the-art MR techniques for cardiac imaging; • List the various approaches to the assessment of cardiac function, perfusion, and viability; • Interpret cardiac MRI in various pathologies; • Explain recent approaches to vessel wall and luminal vascular imaging; and • Describe typical problems in cardiovascular imaging, including artifacts.

Congenital Diseases and Cardiomyopathies 07:00 Congenital and Valvular Disease Jean-Paul Vallée 07:30 Cardiomyopathies and Inflammatory Cardiac Disease David A. Bluemke

MORNING CATEGORICAL COURSE Cell Tracking Rom 713 A/B 7:00 – 8:00 Chair: Jeff W. M. Bulte

Educational Objectives: Upon completion of this course, participants should be able to:

• List at least four methods to label cells; • List disease models in which MRI cell tracking is an important tool; • Recognize which clinical trials have been performed and what is likely needed for future FDA approval; and • Identify what role interventional radiologists will play in the future.

Cell Tracking: Pre-Clinical Applications 07:00 Cell Tracking in Diabetes Anna V. Moore

07:30 Cell Tracking in Neurodegenerative Diseases Piotr Walczak MORNING CATEGORICAL COURSE Hyperpolarization: How to Obtain and Use a 100,000-Fold Increase in Polarization Room 715 A/B 7:00 – 8:00 Chairs: John P. Mugler, III, and Brian K. Rutt

Educational Objectives: Upon completion of this course, participants should be able to:

• Describe “hyperpolarization,” that is, the physical process for generating nuclear polarization in certain gases or compounds that exceeds the thermal-equilibrium polarization achieved in typical MR scanners by several orders of magnitude;

• List the nuclei and compounds for which the hyperpolarized state has been achieved; • Identify the special requirements for MRI or MRS of hyperpolarized contrast media and describe pulse-sequence strategies that meet these

requirements;

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• List imaging and spectroscopy applications of hyperpolarized contrast media in animal models of disease; and • Implement hyperpolarized gas MRI in human pulmonary diseases for which it may improve detection and/or characterization compared to

current modalities.

Hyperpolarized Carbon-13: Methods and Animal Applications 07:00 Acquisition Methods: Hyperpolarized Carbon-13 Charles H. Cunningham 07:30 Applications of Hyperpolarized Carbon-13 in Animals Daniel B. Vigneron

MORNING CATEGORICAL COURSE Tissue Contrast in MSK MRI: From Physics to Physiology Room 717 A/B 7:00 – 8:00 Chairs: Bernard Dardzinski and Timothy J. Mosher

Educational Objectives: Upon completion of this course, participants should be able to:

• Describe the physical and molecular basis for T1, T2, T1p and MT contrast as they relate to collagen-rich tissues; • Identify the effects of tissue anisotropy on relaxation properties; • Apply understanding of mechanism of image contrast in musculoskeletal MRI to clinical and translational research applications; and • Describe the ultra-short TE and T1p techniques and potential clinical applications.

07:00 Tissue Anistropy in Tendons and Cartilage Gary D. Fullerton 07:30 Structural Organization of Cartilage and the Habituation Hypothesis Douglas W. Goodwin

PLENARY LECTURES: The Latest Developments in Cancer Hall F/G 08:15-09:30 Chairs: Robert J. Gillies and Markus Rudin

8:15 412. Towards Personalized Cancer Medicine: Molecular Therapeutics and Biomarkers Paul Workman1 1Institute for Cancer Research, Surrey, UK

In this presentation I will summarize progess and challenges in the development of new therapies designed to exploit the molecular abnormalities that drive the initiation and progression of human cancers. There have been remarkable advances but there are also considerable challenges. The successful development and impact of innovative drugs can be enhanced by the development and application of biomarkers. These include both invasive molecular biomarkers and minimally invasive endpoints. Examples will be provided from our work on the design and development of inhibitors of the PI3 kinase – AKT pathway and of the molecular chaperone HSP90.

8:40 413. Novel Imaging Strategies Preclinical: Molecular Readouts/ Dmitri Artemov1 1Johns Hopkins University, Baltimore, Maryland, USA

MR imaging and spectroscopy provide extensive quantitative morphological and functional information combined with excellent spatial resolution. Traditional nuclear imaging SPECT/PET modalities and more recently optical imaging have intrinsically high sensitivity and can detect tracer amounts of imaging probes that makes these imaging techniques a method of choice for molecular imaging that provide information regarding expression status of molecular targets and/or metabolic and signaling pathways. Adapting MR imaging and spectroscopy to this new class of molecular imaging applications is a challenging but potentially very rewarding problem. Different strategies to achieve this goal are considered and compared in this presentation.

9:05 414. Novel Imaging Strategies Clinical: Cancer Biomarkers George Mills1 1US FDA, Bethesda, Maryland, USA

No synopsis available.

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Pulse Sequences: Post-Cartesian Room 801 A/B 10:30-12:30 Chairs: Peter Börnert and James G. Pipe

10:30 415. Fast Diffusion Imaging Using Undersampled Propeller EPI Mathias Engström1, 2, Anders Nordell1, 3, Bo Nordell1, 3, Stefan Skare4 1Karolinska University Hospital, Stockholm, Sweden; 2Karolinska Institute, Stockholm, Sweden; 3Karolinska Institute, Sweden; 4Stanford University, Stanford, California , USA

A new DWI Propeller reconstruction is presented that dramatically reduces scan time when imaging multiple diffusion directions. By assigning diffusion directions to fewer blades than what is required to grid a full resolution k-space and using a custom gridding procedure, high resolution diffusion tensor imaging is possible in a limited scan time.

10:42 416. Retrospective, Reference-Less Ghosting Correction in PROPELLER EPI Jon-Fredrik Nielsen1, Krishna S. Nayak1 1University of Southern California, Los Angeles, California , USA

In PROPELLER EPI, anisotropic gradient time delays cause 2D phase errors for "oblique" blades that are not aligned with the physical gradient axes, resulting in ghosting that cannot be removed using conventional 1D correction schemes. We propose an approach to 2D phase correction that involves estimating on-axis delays from the acquired PROPELLER EPI data itself, and performing interlaced sampling reconstruction along the phase-encode direction for each blade. The proposed correction technique is performed retrospectively, and does not require reprogramming the pulse sequence or obtaining additional reference scans.

10:54 417. Calibration Free Distortion Correction for Propeller EPI Stefan Skare1, Jesper LR Andersson2, Roland Bammer1 1Stanford University, Palo Alto, California , USA; 2Oxford University, Oxford, UK

GRAPPA accelerated short-axis propeller EPI (SAP-EPI) has earlier been shown to be a promising sequence for high-resolution diffusion imaging due to its low distortion properties. In this work, we have developed an extended model of the reversed gradient polarity method to correct for the residual geometric distortions in SAP-EPI. This algorithm estimates a single distortion field from all blades simultaneously, instead of pair-wise correction of two oppositely distorted blades as previously done. This makes the field estimation process more overdetermined and allows us to perform the correction using only blades acquired over 0 to 180 degrees.

11:06 418. A Method for Removing Off-Resonance Artifact in Turboprop James G. Pipe1, Donglai Huo1, Eric Aboussouan1, Zhiqiang Li2 1Barrow Neurological Institute, Phoenix, Arizona , USA; 2GE Healthcare, Phoenix, Arizona , USA

Turboprop is a fast PROPELLER hybrid of FSE with EPI-like echo trains. Compared to conventional PROPELLER, it reduces SAR and increases sampling efficiency, but introduces artifacts from off-resonance. This work illustrates a method to dramatically reduce these artifacts, at the expense of narrower blade-widths.

11:18 419. Targeted-PROPELLER MRI Jie Deng1, 2, Andrew C. Larson1 1Northwestern University, Chicago, Illinois, USA

Multi-shot TSE-based PROPELLER imaging has been shown to be less sensitive to motion artifacts. However, PROPELLER imaging requires longer imaging time compared to conventional TSE due to oversampling of k-space. Also, it has been demonstrated that regional motions cannot be effectively corrected based on an entire image including both static and moving objects. In this study, we propose a targeted-PROPELLER technique employing inner-volume excitation method to limit the field-of-view (FOV) for (i) imaging a small ROI to shorten imaging time and (ii) targeting the moving objects for robust regional motion correction.

11:30 420. Abdominal Imaging in Free-Breathing Mice Using PROPELLER Prachi Pandit1, Kevin F. King2, G Allan Johnson1 1Duke University, Durham, North Carolina, USA; 2GE Healthcare, Waukesha, Wisconsin, USA

T2-weighted and diffusion-weighted imaging is effective for tumor visualization, but it is challenging in free-breathing mice due to higher spatial resolution and faster physiologic motion. The requirements in this case are: immunity to cardiac and respiratory motion; short TE to minimize T2* decay at the higher magnetic fields required for mice; and short scan time with long TR required for T1 recovery. In this work, we use the PROPELLER sequence on a 7T scanner with high strength, rapid gradient coils to acquire artifact-free abdominal images in free-breathing mice with good T2-weighting and in-plane resolution of 97µm.

11:42 421. Assessment of Concomitant Gradient Blurring in Spiral In-Vivo Scans at 1.5 T Christopher Thomas Sica1, Craig H. Meyer1 1University of Virginia, Charlottesville, Virginia , USA

Off-resonance phase in spiral scans can lead to undesirable blurring artifacts. An important but not commonly considered source of off-resonance phase is concomitant gradients. In this abstract, we demonstrate the severity of the concomitant gradient artifact in spiral in-vivo scans at 1.5T. In-vivo data sets with varied scan plane orientations and offsets were acquired to qualitatively assess the concomitant blurring pattern, and the distance from isocenter at which blurring starts to become significant. Concomitant blurring starts to becomes an issue around 6-7.5 centimeters from isocenter in the z direction, across a multitude of scan plane orientations.

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11:54 422. Optimization of Undersampled Variable Density Spiral Trajectories Based on Incoherence of Spatial Aliasing Yoon-Chul Kim1, Krishna S. Nayak1 1Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California , USA

Variable density spiral (VDS) imaging typically samples low spatial frequencies densely and samples high spatial frequencies sparsely to achieve higher temporal or spatial resolution than uniform density spiral (UDS) imaging. Reconstructed images are prone to aliasing artifacts due to the undersampling of high spatial frequencies, but they are often considered to be acceptable. However, unlike UDS, VDS imaging requires an appropriate selection of variation in sampling density. We propose a way of optimizing VDS trajectory design based on its point spread function and demonstrate its effectiveness in phantom studies.

12:06 423. A Fast Method for Designing Time-Optimal Gradient Waveforms for Arbitrary K-Space Trajectories Michael Lustig1, Seung Jean Kim1, John Mark Pauly1 1Stanford University, Stanford, California , USA

A fast and simple algorithm for designing time-optimal waveforms is presented. The algorithm accepts a given arbitrary multi-dimensional k-space trajectory as the input and outputs the time-optimal gradient waveform that traverses k-space along that path in minimum time. The algorithm is non-iterative, and its run time is independent of the complexity of the curve, i.e. the number of switches between slew-rate limited acceleration, slew-rate limited deceleration and gradient amplitude limited regions. The key in the method is that the gradient amplitude is designed as a function of arc length along the k-space trajectory, rather than as a function of time. Several trajectory design examples are presented.

12:18 424. Variable Density Bunched Phase Encoding Hisamoto Moriguchi1, Jeffrey L. Duerk2, Yutaka Imai1 1Tokai Unversity School of Medicine, Isehara, Japan; 2University Hospitals of Cleveland/Case Western Reserve University, Cleveland, Ohio, USA

Bunched Phase Encoding (BPE) has recently been proposed as a new fast data acquisition method in MRI. In BPE, zigzag k-space trajectories often need to be measured because actual trajectories often deviate from designed trajectories due to eddy currents. This may limit actual implementation of BPE. In this study, we show an improved BPE acquisition method that does not require k-space trajectory measurement. In our newly proposed method, variable density (VD) zigzag trajectories are used. VD-BPE obviates the need for cumbersome k-space trajectory measurement and achieves accurate image reconstruction. VD-BPE is quite useful and facilitates implementation of BPE in practice.

Fiber Tracking & Connectivity Mapping Room 718 A 10:30-12:30 Chairs: Derek K. Jones and Mariana Lazar

10:30 425. Young Investigator Award Finalist: Gibbs Tracking: A Novel Approach for the Reconstruction of Neuronal Pathways Björn Wolf Kreher1, Irina Mader2, 3, Valerij G. Kiselev1 1University Hospital Freiburg, Freiburg, Germany; 2Neurocenter of the University Hospital Freiburg, Freiburg, Germany; 3Department of Neurology of the University Hospital Freiburg, Freiburg, Germany

The known fibre tracking methods are commonly based on the ‘walker-principle’. There, fibres are reconstructed as trajectories of ‘walkers’ which are guided either deterministically or randomly according to the local properties of the diffusion-weighted signal. In this study, a principally new method of fibre tracking is proposed which is not based on any ‘walking’ algorithm. It resolves a number of inherent problems of the ‘walking’ approach being capable to reconstruct crossing and spreading fibre configurations. The performance of this new method is shown in simulation and in an in vivo measurement

10:50 426. Probabilistic Diffusion-Tensor Fiber Tractography in a Bayesian Framework with an Atlas Prior Philip A. Cook1, Hui Zhang1, Suyash P. Awate1, James C. Gee1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA

This work uses a diffusion-tensor atlas to guide probabilistic tractography in a Bayesian framework. The spatial normalization explicitly optimizes tensor similarity to provide optimal alignment of white matter. The mean and variance of the fiber orientation in each voxel is used as a prior for the tractography method. We demonstrate the method using an atlas constructed from eleven subjects and atlas-guided tracking in one subject. Results are shown from tracking of the cingulum, formix, and mid-cerebellar peduncle. In each case, the atlas prior increases the connectivity along the pathway relative to an equivalent method without a prior.

11:02 427. Quantitative Validation of MR Tractography Using the CoCoMac Database Patric Hagmann1, Xavier Gigandet2, Reto Meuli1, Rolf Kötter3, Olaf Sporns4, Van J. Wedeen5 1University Hospital Center and University of Lausanne, Lausanne, Switzerland; 2Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; 3Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands; 4Indiana University, Bloomington, USA; 5Harvard Medical School, Charlestowm, Massachusetts, USA

We quantitavely characterize MR tractography performance in terms of sensitivity and specificity by comparing the connection matrix of an MR tractography experiment in a fixed macaque hemisphere with a set of histologic tracing studies made in the same species that establish 313 connections as well as 469 absent connections. Computing the Receiver Operator Characteristic curve, we see that MR tractography agrees significantly with the gold standard. Typically a sensitivity of 60% for a specificity of 70% can be achieved.

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11:14 428. Combining Tractography and Coherence Measures to Identify Connectivity Within a Neural Network for Reading Stephen Welbourne1, Karl Embleton1, Hamied Haroon1, David Morris1, Geoffrey J M Parker1, Matthew Anthony Lambon Ralph1 1University of Manchester, Manchester, UK

PICo probabilistic tractography was used to investigate the anatomical connectivity of functional networks which had been suggested by two previous studies on reading. Functional connections identified by the MEG study were found to be significant predictors of the tractography results; however functional connections from the DCM study did not significantly predict the tractography results. More detailed analysis of the pattern of results suggests that while there was strong evidence supporting most of the MEG connections two of the hypothesised connections were not supported by tractography. It is suggested that tractography has a useful part to play in constraining model selection.

11:26 429. Quantification of White Matter Fiber Orientation at Tumor Margins with Diffusion Tensor Invariant Gradients Gordon Kindlmann1, Stephen Whalen1, Ralph O. Suarez1, Alex J. Golby1, Carl-Fredrik Westin1 1Harvard Medical School, Boston, Massachusetts, USA

Existing applications of Diffusion Tensor Imaging (DTI) to neurosurgical planning of tumor resection focus on the tensor principal eigenvector (either in visualization with RGB colormaps, or connectivity analysis by tractography), or on changes to scalar-valued tensor invariants such as trace (as with edema) or fractional anisotropy (axonal destruction). We present new metrics, Diffusion Angle (Da) and Diffusion Fraction (Df), for characterizing fiber orientation relative to affected regions, based on measuring the spatial gradients of tensor invariants. The metrics are motivated in terms of their expected behavior along cortical gyrii, and initially evaluated on a clinical brain tumor case.

11:38 430. Computing Strings of Average HARDI Models Using Procrustes-Based Fibre Alignment Irina Kezele1, Cyril Poupon1, Muriel Perrin2, Yann Cointepas1, Vincent El Kouby1, Fabrice Poupon1, Jean-François Mangin1 1CEA NeuroSpin, Gif sur Yvette, France; 2GE Healthcare, Buc, France

The idea underpinning the work we present is to design robust and objective tools for brain white matter (WM) morphometry. We focus on WM tracts, and propose to represent them by their mean lines, to which we associate the attributes derived from high-angular resolution diffusion imaging (HARDI).The definition of the tract mean line derives directly from the geometry of the tract fibres. We determine the fibre point correspondences and impact factors of individual fibres, upon which we estimate average HARDI models along tract mean lines, thus obtaining a compact tract representation free of the outlier influence and undesired edge effects.

11:50 431. Software Tool to Generate Complex Structures for Validation of Fibre Tracking Tom G. Close1, 2, J-Donald Tournier1, 3, Fernando Calamante1, 3, Leigh A. Johnston, 24, Iven Mareels, 23, Alan Connelly1, 3 1Brain Research Institute, Melbourne, Australia; 2National ICT Australia, Melbourne, Australia; 3University of Melbourne, Melbourne, Australia; 4Howard Florey Institute, Melbourne, Australia

Despite important advances in fibre-tracking algorithms, the field is currently limited by the lack of a ‘gold standard’. Current validation methods (e.g. comparisons with known anatomy, ex vivo measurements and simulated data) suffer from limitations and/or uncertainties. We have developed a fast flexible software-tool that can generate random models of fibre bundles with a complexity comparable to white matter structures. This provides an essential tool for current and future tracking algorithms to be robustly tested, and their limitations more thoroughly understood.

12:02 432. Visualisation of CSI Metabolite Concentrations Along Specific White Matter Tracts Hannah Joan Coward1, Ruth Louise O'Gorman1, 2, David J. Lythgoe1, Marco Catani1 1Institute of Psychiatry, London, UK; 2King's College Hospital, UK

Diffusion Tensor Imaging (DTI) is a non-invasive method to visualise gross white matter architecture and probe microstructural integrity of both normal and pathological brain. Equivalently, quantitative Magnetic Resonance Spectroscopy (MRS) is a non-invasive technique used to measure metabolic concentrations, changes of which have been documented in several neurological disorders. Here preliminary work that combines MRS Chemical Shift Imaging (CSI) with DTI-tractography is presented. Our aim is to assess the feasibility of performing tract-specific measurements of MRS brain metabolites along the left arcuate fasciculus (AF).

12:14 433. Using Boy’s Real Projective Plane Immersion for Coloring DT-MRI Slices Cagatay Demiralp1, John F. Hughes1, David H. Laidlaw1 1Brown University, Providence, Rhode Island, USA

We introduce Boy’s surface, an immersion of the projective plane (RP2) in 3D, as a model for mapping tensor orientation to colors. One of the most popular methods of visualizing DT-MRI slices is to map principal eigenvectors of the underlying tensors to RGB colors. All the existing variations of this method, however, suffer from mirror symmetry one way or another. Ideally, we would like to map 1) different orientations to different, unique colors and 2) similar orientations to similar colors. As trivial as it sounds, this task is not easy and there is a compelling reason for that: The problem of smooth, one-to-one assignment of colors to orientations is tantamount to embedding the real projective plane in 3D, which was proven to be impossible. While the real projective plane does not have an embedding in 3D, it has immersions. Here, we present Boy’s immersion of the real projective plane for mapping orientation to colors. Boy’s surface is the only real projective plane immersion without singularities. Coloring based on this model (we refer it as RP2 coloring) will map different orientations to different and similar colors, except along the self-intersection curve.

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Receive Concepts & Arrays Room 718 B 10:30-12:30 Chairs: Greig C. Scott and Graham C. Wiggins

10:30 434. Traveling Wave MR on a Whole-Body System David Otto Brunner1, Nicola De Zanche1, Jan Paska, Juerg Fröhlich, Klaas Paul Pruessmann1 1University and ETH Zurich, Zurich, Switzerland

With increasing frequencies of MR systems, RF probe design becomes significantly more difficult due to shrinking wave length. The resulting RF fields become more inhomogeneous and the area of efficient reactive coupling to the spins becomes smaller. Hence we propose to abandon near field coupling in MR probe design and rely on propagating field coupling realized by traveling waves. The effectiveness, feasibility and advantages of this approach are demonstrated by high-resolution images as well as whole-body images at 7T taken from phantoms placed 65 cm a way from the RF probe showing excellent SNR and image homogeneity.

10:42 435. Non-Resonant Microstrip (NORM) RF Coils: An Unconventional RF Solution to MR Imaging and Spectroscopy Xiaoliang Zhang1, 2, Chunsheng Wang1, Zhentian Xie1, Bing Wu1 1University of California San Francisco, San Francisco, USA; 2UCSF/UC Berkeley Joint Graduate Group in Bioengineering, San Francisco & Berkeley, USA

A non-resonant RF coil technique for MR imaging and spectroscopy is proposed. This technique can dramatically simplify the conventional RF coil design and overcome numerous technical difficulties in designing high frequency coils, multiple tuned coils and parallel imaging coil arrays. MR sensitivity comparison with a conventional resonant coil shows the reception efficiency or MR sensitivity of the non-resonant coil is comparable with that of the conventional resonant coil. Because of the non-resonance property, a non-resonant coil can be used for all kinds of NMR sensitive nuclei at all kinds of different field strengths.

10:54 436. A 6-Element Coil Array for Parallel Imaging in Arbitrary Directions Matthias Korn1, Reiner Umathum1, Sven Müller1, Wolfhard Semmler1, Michael Bock1 1Deutsches Krebsforschungszentrum (dkfz), Heidelberg, Germany

A 6-channel rf-coil array for small-animal imaging at clinical 3T MRI systems is presented. Two coil-arrays each consisting of a loop, a butterfly and a saddle-train-coil side by side were build and assembled to form a 6-channel array. Due to position and geometry the elements have orthogonal sensitivity profiles and low mutual coupling. MR experiments were performed showing the applicability of the setup for parallel imaging with encoding in arbitrary directions.

11:06 437. 16-Channel Microstrip Array Using 1st and 2nd Harmonics for Parallel Imaging at 7T Bing Wu1, Chunsheng Wang1, Zhentian Xie1, Xiaoliang Zhang1, 2 1UCSF, San Francisco, California , USA; 2UCSF/UC Berkeley Joint Graduate Group in Bioengineering, San Francisco & Berkeley, California , USA

High field parallel imaging, as a promising imaging modality, offers high spatial resolution and high temporal resolution simultaneously. However, design of required high frequency parallel RF coil arrays, especially dense-spaced human coil arrays, faces many daunt technical challenges in attaining sufficient EM decoupling, image homogeneity and better geometry factors (g-factor). In this work, we propose a novel technique for the array design using the 1st and 2nd harmonics of microstrip resonators. This technique provides improved image homogeneity, intrinsic element-decoupling that allows of increased channel number, and better parallel imaging performance with reduced g-factor, Based on the proposed technique, a 16-ch microstrip array with alternatively placed 1st and 2nd harmonic resonance elements was designed and tested for 7T parallel imaging applications.

11:18 438. Tic Tac Toe: Highly-Coupled, Load Insensitive Tx/Rx Array and a Quadrature Coil Without Lumped Capacitors Tamer S. Ibrahim1, YiK-Kiong Hue1, Ryan Gilbert1, Fernando E. Boada1 1University of Pittsburgh, Pittsburgh, Pennsylvania, USA

This work presents a new coil design, Tic-Tac-Toe, that is highly load insensitive (negate high-field/frequency electromagnetic effects), yet is highly coupled (utilizes inherent SNR properties associated with coupled coils.) The Tic-Tac-Toe was successfully tested as a transmit/receive array and as a standard 4-port quadrature coil at 7 tesla.

11:30 439. An 8-Channel Array Adapted for Pediatric Cardiac Imaging Thomas Grafendorfer1, Frandics Pak Chan2, Greig Scott2, Richard A. Barth2, Roland Bammer2 1GE Healthcare, Stanford, California , USA; 2Stanford University, Stanford, California , USA

One of the major shortcomings of pediatric cardiac MRI is the lack of appropriate coils leading to makeshift solutions with adult coils that yield suboptimal SNR and mediocre parallel imaging support. In fact, it is not uncommon that the size of one element of an adult array coil is larger than the width of the chest of a pediatric patient. That said, the availability of parallel imaging would be of utmost importance for these exams as these patients usually have significantly higher heart rates, are less compliant for breath-hold scans or should not be kept too long under general anesthesia due to their already very unstable clinical condition.

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11:42 440. A 128-Channel Helium-3 Phased Array at 3T for Highly Accelerated Parallel Imaging in Hyperpolarized Gas MRI Ray F. Lee1, Hugo Chang2, Cornel Stefanescu3, Bernd Stoeckel2, Davide Santoro3, Debra Strick4, Rong Xue3, Niels Oessingman2, Glyn Johnson3, Daniel Sodickson3 1Princeton University, Princeton, New Jersey, USA; 2Siemens Medical Solution USA, New York, New York, USA; 3New York Unviersity Medical Center, New York, New York, USA; 4University of California Los Ageles, Los Angeles, California , USA

A 128-ch Helium-3 coil array at 3T was developed to take advantage of parallel imaging with hyperpolarized gas in lung MRI. The large number coil array enables us to study that at which acceleration factor, the SNR benefits from both hyper-polarization and under-sampling in non-equilibrium state are neutralized by the increasing g-factor. Five volunteers have been scanned with this coil using 2D GRE sequence with iPAT 1, 4, and 8. No appreciable SNR difference between iPAT 1 and 4 was found. The results with iPAT=8 produced the first evidence that the image integrity can be well preserved at high acceleration factor.

11:54 441. Flexible Microcoils for In-Vivo Biliary Imaging Munir Ahmad1, Warren Casperz2, Ian Young1, Simon Taylor-Robinson2, Richard Syms1, Wady Gedroyc2 1Imperial College London, London, UK; 2St Mary¡¦s Hospital, Imperial Research NHS Trust, London, UK

A detector coil is described for use with an MR-compatible biliary endoscope. The coil has to pass down through a 3.2mm diameter channel, then turn through a right angle before being passed along the bile duct for 50mm or more. The coil is designed for high resolution imaging. Silicon semiconductor manufacturing techniques have been used in its manufacture, with the silicon, which is very brittle and inflexible, and is not at all biocompatible, being removed at the end to leave a copper coil embedded in plastic. Phantom images which show its current performance are shown.

12:06 442. Coil Geometry Optimization for Better SNR and Decoupling George Carlos do Nascimento1, Shumin Wang1 1National Institutes of Health, Bethesda, USA

The restricted clearance space for arrays coils for animals imposes significant limitations and difficulties to avoid strong mutual couplings. We present a study of coil geometries for improved SNR. Loops made with circular wires were compared with a circular flat strip and with a circular loop. By using the Surface Integral Equation method, coils with different sizes were simulated, and as a result, coils were optimized. Experimental evaluation of these coils was realized by MRI. In particular, a cylinder shaped coil shows a better profile for the field map, better SNR and also less coupling to the neighbor loop coil.

12:18 443. Cryogenic Varactor-Tuned 4-Element Array and Cryostat for µ-MRI of Trabecular Bone in the Distal Tibia Jarek Wosik1, Krzysztof Nesteruk2, Maged R. Kamel1, Flora Ip1, Lian Xue1, Alexander C. Wright3, Felix W. Wehrli3 1University of Houston, Houston, USA; 2Institute of Physiscs Polish Academy of Sciences, Warsaw, Poland; 3University of Pennsylvania Medical Center, Philadelphia, USA

We report on the development of a clinically practical cryogenic array and cryostat assembly for use in a 3 T MRI scanner to provide increased SNR in µ-MRI studies of trabecular bone in the distal tibia. Both cryogenic copper and superconducting (HTS) materials are explored. Each array element is a double-layer rotated split copper ring, separated by 0.5 mm dielectric. A plastic liquid nitrogen cryostat was custom made to integrate with remotely controlled varactor-based tuning/matching/decoupling circuitry. Performance of the array is under investigation and more than two-fold SNR gain is expected, confirmed by gains obtained on a single element.

Assessing Tumor Perfusion & Permeability Using MRI Room 714 A/B 10:30-12:30 Chairs: Edna Furman-Haran and Anwar R. Padhani

10:30 444. Monitoring Non Invasively by Contrast Enhanced MRI the Decrease in Tumors Interstitial Fluid Pressure Following Collagenase Treatment Yaron Hassid1, raanan margalit1, Erez Eyal1, Edna Furman-Haran1, Hadassa Degani1 1Weizmann Institute of Science, Rehovot, Israel

Many solid tumors show an increased interstitial fluid pressure (IFP), which forms a physical barrier to drug delivery. We developed a model-based analysis of slow infusion CE-MRI, which integrates GdDTPA pharmacokinetics during slow i.v. infusion and its distribution at steady state. This method was applied to test the efficacy of collagenase in modulating IFP in human H460 non-small-cell lung carcinoma xenografts that exhibited high IFP. Sequential CE-MRI monitoring studies have shown that collagenase significantly reduced tumor IFP within 5 h after its administration. This was further confirmed by the 'wick in needle' technique.

10:42 445. The Effect of Tumor Proteases on Invasion and Vascularisation Eva Christina Woenne1, 2, Stefan Zwick1, 2, Ralph Strecker3, Arne Hengerer2, Matthias Taupitz4, Joerg Schnorr4, 5, Margareta M. Mueller1, Wolfhard Semmler1, Fabian Kiessling1 1German Cancer Research Center, Heidelberg, Germany; 2Siemens Medical Solutions, Erlangen, Germany; 3Siemens Medical Solutions, Erlangen , Germany; 4Charité, Berlin, Germany; 5Ferropharm, Teltow, Germany

Vessel Size Imaging (VSI) can be used to determine the mean vessel diameter in tumors. In this study the effect of Matrix-Metallo-Proteinases inhibition (MMPI) on VSI and tumor vascularity (HF-VPDU) was investigated. Upon MMPI vascularity decreased, while mean tumor vessel diameter increased in tumor xenografts of nude mice. Taking into account histological analyzes, the increasing mean tumor vessel diameter can be explained by regression and maturation of small vessel and might be triggered by the change of VEGF und PDGF expression that we observed in vitro upon MMPI.

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10:54 446. Combination of DCE and DSC MRI: Added Value in the Study of Tumor Vascularization Melanie Heilmann1, 2, Steven Sourbron3, Christine Walczak1, 2, Andreas Biffar3, Julien Vautier1, 2, Michael Peller3, Andreas Volk1, 2 1Institut Curie, Orsay, France; 2INSERM, Orsay, France; 3Ludwig-Maximilian-University Munich, Munich, Germany

Combination of DCE and DSC MRI was realized by simultaneous measurement of T1 and T2* kinetics. In a subcutaneous xenograft model implanted in nude mice examined at 4.7T, a 6 kDa CA was suitable for assessing heterogeneous capillary permeability by measuring Ktrans, whereas a 0.5kDa CA yielded perfusion weighted Ktrans values. Furthermore, a description of R2*(t) in the presence of CA leakage was proposed yielding the parameters κ 20 and κ 21. They are thought to be related to intra-voxel cellular distribution and vascular architecture. Combined DCE-DSC MRI holds potential to improve tumor characterization.

11:06 447. Post-Radiation Change in MRI Dynamic Contrast Enhanced Ktrans Did Not Explain Tumor Reoxygenation of Irradiated Naturally-Occurring Canine Tumors Susan Kraft1, Nadira Trncic2, Ed Ashton3, Susan LaRue1 1Colorado State University, Fort Collins, USA; 2Colorado State University, Fort Collins , USA; 3VirtualScopics Inc, Rochester, New York, USA

Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) was performed on 9 dogs with naturally-occurring tumors before and after a 3 Gy fraction of radiation. In conjunction with DCE-MRI, we measured tumor oxygen levels, microvascular perfusion and density, apoptosis and interstitial fluid pressure to investigate mechanisms involved in reoxygenation. All hypoxic tumors became normoxic after the 3 Gy fraction, with increased mean/median pO2 and decreased hypoxic fraction, whereas mean Ktrans decreased. This Ktrans decrease occurred in the presence of decreased interstitial fluid pressures and increased apoptosis, so improved vascular delivery did not explain the concurrent reoxygenation of tumors.

11:18 448. Novel Insights Into Intravenous Bradykinin Analogue-Mediated Vasomodulation from Dynamic Contrast-Enhanced MRI of RG-2 Rodent Malignant Gliomas Hemant Sarin1, 2, Steve Huntz Fung, 12, Ariel Shaya Kanevsky1, Auh Sungyoung1, John Alexander Butman1 1National Institutes of Health, Bethesda, USA; 2Massachusetts General Hospital, Boston, USA

Intravenous infusion of Cereport, a synthetic bradykinin analogue, has been shown by quantitative autoradiography (QAR) to temporarily enhance drug delivery to malignant gliomas. Although historically QAR has been utilized to measure tumor vascular parameters during systemic vasomodulation, the major limitations of this method include incompleteness of vascular input function (VIF) shape determination due to manual sampling of blood at only certain specific time points, and inability to acquire tumor tissue concentration data over time in the same animal. DCE MRI allows for continuous measurement of change in Gd-DTPA concentration within brain vasculature and glioma tissue over time. In this study we utilized Gd-DTPA DCE MRI to measure changes in tumor vascular parameters within the same RG-2 rat glioma at baseline and during systemic vasomodulation with short-acting and long-acting bradykinin analogues, Met-Lys-bradykinin (Met-Lys-BK) and Cereport, respectively.

11:30 449. Vessel Size Index MRI: Validation with Micro-CT Angiography Sharon E. Ungersma1, Calvin Ho1, Glenn Pacheco1, Jed Ross1, Joan M. Greve1, Franklin V. Peale Jr. 1, Sarajane Ross1, Richard A. D. Carano1 1Genentech, Inc., South San Francisco, California , USA

Vessel size index MRI uses changes in T2 and T2* after introduction of an iron oxide contrast agent to determine the mean vessel size within a voxel. One method by which vessel size measurements of tumors have been done previously is ex vivo micro-CT angiography. Here, we validate the VSI measurement by correlation with micro-CT vessel size measurements of the same tumors. We restrict the VSI analysis to viable tumor tissue as determined with multispectral clustering. This requires no additional scans beyond the VSI measurement and can improve accuracy of MRI parameter measurement by eliminating necrotic regions from the analysis.

11:42 450. DOCENT- Dynamic Oxygen Challenge Evaluated by NMR T1 and T2* of Tumors Jesus Pacheco-Torres1, 2, Dawen Zhao1, Angelina Contero1, Peter Peschke3, Ralph Peter Mason1 1The University of Texas Southwestern Medical Center, Dallas, Texas, USA; 2 Instituto de Investigaciones Biomédicas "Alberto Sols" - CSIC, Madrid, Spain; 3DKFZ German Cancer Center, Heidleberg, Germany

Hypoxia influences tumor response to therapy: thus techniques are needed to assess hypoxia and potential modulation. T2*-weighted (BOLD) and T1-weighted (TOLD: Tissue Oxygen Level Dependant) contrast MRI should provide insight into tumor oxygenation. We examined these non-invasive techniques as surrogates for quantitative pO2 measurements for response to carbogen breathing of two tumor sublines (AT1 and HI) noted for their different levels of hypoxia and response to hyperoxic gas breathing. Changes in T1- and T2*-weighted signal intensities corresponded with quantitative 19F NMR oximetry. Since such measurements are entirely non-invasive they offer the potential rapid translation to the clinic.

11:54 451. Investigating the Influence of Physiological Variation on the Form of the Arterial Input Function in DCE-MRI Ross A. Little1, Caleb Roberts1, Yvon Watson1, Marietta Scott2, Gio A. Buonaccorsi1, Susan Cheung1, Karen Davies1, James P. O'Connor1, Geoff J. Parker1 1University of Manchester, Manchester, UK; 2AstraZeneca, Macclesfield, Cheshire, UK

This study investigates associations between arterial input functions (AIFs) and readily-available physiological measurements to assess whether change in AIF form between individuals is due to measurement noise and error or if there are detectable underlying physiological influences. Forward stepwise multiple linear regression models were constructed and first pass peak height (FPPH) and the ratio of second pass peak height to FPPH were found to be related to age (r2 = 0.30 and 0.47 respectively). The measured AIF does seem to reflect underlying physiological variation and it may be possible to utilise this to improve the accuracy of population representative AIFs.

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12:06 452. Prediction of Treatment Response in Head and Neck Cancer Using DCE-MRI Sungheon Kim1, Laurie A. Loevner1, Larry Dougherty1, Harry Quon1, Eric J. Sherman1, Gregory S. Weinstein1, Harish Poptani1 1University of Pennsylvania, Philadelphia, USA

The purpose of this study was to evaluate the feasibility of using DCE-MRI data with the shutter-speed model (SSM) analysis to predict response to chemo/radiation therapy in the head and neck squamous cell carcinoma (HNSCC). MRI data was acquired from thirty two patients who were newly diagnosed with HNSCC with no prior treatment. Pretreatment transfer constant (Ktrans) and intracellular water exchange time (ti) showed significant difference between the complete responders and partial responders, determined at the end of the treatment. Classification of treatment response based on SSM parameters had a sensitivity of 100% and a specificity of 75%.

12:18 453. DCE-MRI of Human Brain Tumors Using Gadoteridol and Ferumoxytol Jeffrey Moses Njus1, Csanad G. Varallyay2, John W. Grinstead3, Xin Li1, Charles S. Springer, Jr. 1, Edward A. Neuwelt2, William D. Rooney1 1Oregon Health and Science University, Portland, Oregon, USA; 2Oregon Health and Science University, Portland, USA; 3Siemens Medical Solutions, Inc, Portland, USA

In regions of high vascular permeability, as is typical in glioblastoma multiforme (GBM), the accurate quantification of blood volume can be difficult or impossible using low molecular weight Gd(III) contrast reagents (CR). This difficulty may be overcome using macromolecular iron oxide CRs such as ferumoxytol, which remain essentially intravascular at short times after administration; even in malignant brain tumors. In this study, we demonstrate a simple, yet novel mapping method using a Gd and an iron-oxide CR serially to quantify cerebral blood volume and BBB permeability in human GBM.

Renal Parenchymal & Perfusion MR Imaging Room 716 A/B 10:30-12:30 Chairs: Harriet C. Thoeny and Shih-Chang Wang

10:30 454. A Simple Two-Compartment Model That Describes Dynamic Contrast-Enhanced MRI Signal in the Kidney Paul S. Tofts1, Iosif A. Mendichovszky2, David L. Buckley3, Kenneth A. Miles1, A Michael Peters1, Isky Gordon2 1Brighton and Sussex Medical School, Brighton, UK; 2University College, London, UK; 3Manchester Medical School, UK

A two-compartment model, based on widely-accepted work in tumours, is able to fit the complexity of DCE renal data with 2.5s temporal resolution. The bolus delay and dispersion from aorta to kidney are accounted for in the model. The estimated parameter K-trans is the GFR per unit volume of kidney. In 10 normals controls, the mean value was 0.48 min-1 (sd=0.09), close to established values. Repeated measurements showed differences of 30% (1sd). The model was implemented on a simple spreadsheet. The model overcomes problems with the established Patlak approach. Significant Gd efflux from parenchymal voxels was found even after 30s.

10:42 455. DCE MRI Based Perfusion Parameters in Renal Transplants: Influence of the Choice of the Arterial Input Function Martine Isabella Dujardin1, Steven Sourbron2, Rob Luypaert1, Yves Fierens1, Jacques Sennesael3, Tadeusz Stadnik1, Johan de Mey1 1UZ Brussel, Brussels, Belgium; 2Klinikum Grosshadern, Munich, Germany; 3UZ brussel, Brussels, Belgium

This study tries to estimate the influence of dispersion and partial volume by comparing quantitative DCE-based perfusion results in renal transplant data deconvolved with two AIFs. RVDlob (small proximate lobar artery AIF) values are higher than RVDil (more distant iliac artery AIF), consistent with AIF underestimations due to partial volume effects. In MTT the trend in the data (MTTlob smaller compared to MTTil) can be attributed to bolus dispersion. RBF is influenced by both effects, but the results show that partial volume effects dominate. We conclude that for quantitative DCE-based perfusion parameters in transplants the choice of the AIF in a larger more distant artery is more accurate.

10:54 456. Assessment of Renal Function Using MR Renography Without Aortic Input Information Jeff Lei Zhang1, Henry Rusinek1, Qun Chen1, Pippa Storey1, Louisa Bokacheva1, Ting Song1, 2, Vivian S. Lee1 1New York University, New York, New York, USA; 2Columbia University, New York, New York, USA

Most current models for analyzing MR renographic data require an aortic input curve, which suffers from several measurement errors. In this study, we explored a new approach that estimates GFR but obviates input function measurements. Patient study showed that the root mean square errors for fitting medullary curve averaged only 0.016 ± 0.006 mM, and there was excellent correlation (R = 0.95) between the proposed parameter à and GFR measured by scintigraphy. The Monte Carlo simulation indicated that parameter à could be estimated with high precision and accuracy under typical levels of noise.

11:06 457. Noninvasive Monitoring of Acute Tubular Necrosis Induced by Ischemia/Reperfusion in a Rat Model Using 23Na MRI Bharath Atthe1, Andriy Babsky1, Navin Bansal1 1Indiana University School of Medicine, Indianapolis, USA

23Na MRI was applied to study the early alteration in renal sodium distribution in the rat kidney with acute tubular necrosis (ATN) using the ischemia-reperfusion injury model. The images showed ~80% higher 23Na MRI SI in the medulla compared to the cortex. The medulla to cortex Na+ gradient decreased progressively after 10, 30 and 50 min of ischemia. No recovery was observed after 1 hour of reperfusion in the 30 and 50 min ischemia groups, suggesting irreversible tubular injury. 23Na MRI should prove useful as a noninvasive technique for diagnose of evolving ATN.

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11:18 458. Measurement Precision of Gadolinium Enhanced Magnetic Resonance Nephro-Urography Using Rapid 3D Imaging and a Multi-Compartment Kinetic Model Khalil Nabeel Salman1, Puneet Sharma1, Bobby Kalb1, John Votaw1, Diego R. Martin1 1Emory University, Atlanta, Georgia, USA

It is currently known that an estimation of renal perfusion kinetics can be determined non-invasively using MRI perfusion techniques. Apart from accuracy, the utility of such techniques depend highly on the precision of the acquisition and kinetic modeling steps, to ensure the physiological parameters are comparable and applicable clinically. The purpose of this investigation was to determine precision of kinetic parameters of the kidney in normal subjects, using an accelerated volumetric acquisition technique and semi-automated kinetic modeling steps. From the results, the standard deviations for all measurement variables were low, ensuring measurement reproducibility.

11:30 459. DCE-MRI Demonstrates Immediate Post-Perfusion Microvascular Hyperpermeability in the Mouse Renal Cortex Following Ischemia Induced by Renal Artery Clamping Negar Geula Knowles1, Li-wen Lai1, Suzu Igarashi1, Christine M. Howison1, Y. Howard Lien1, Natarajan Raghunand1 1University of Arizona, Tucson, Arizona , USA

DCE-MRI imaging of the mouse kidney following surgically induced ischemia and reperfusion was performed using an intravascular contrast agent. Enhancement curves centered over the renal cortices in the reperfused and control kidneys demonstrate a period of slow uptake of contrast in the reperfused renal cortex following the initial steep slope of contrast uptake. This pattern, not seen in the control kidney, is likely due to capillary leak with interstitial retention of contrast following reperfusion. T1-weighted contrast-enhanced images demonstrate enlargement of the reperfused kidney and increased corticomedullary differentiation, attributed to increased capillary permeability in the reperfused cortex.

11:42 460. Renal Tracer Kinetics with a Reabsorption Correction Steven Sourbron1, Henrik J. Michaely2, Stefan O. Schoenberg2, Maximilian F. Reiser, Michael Peller1 1Ludwig-Maximilian-University Munich, Munich, Germany; 2Universitaetsklinikum Mannheim, Mannheim, Germany

A 2- and 3-compartment model are proposed to account for the effect of reabsorption in renal tracer kinetics. Possible applications of the models are assessed analytically, and the methods are evaluated using data from healthy kidneys. Both allow a measurement of the reabsorption fraction, provided additional data are available in the form of a venous outflow curve. Measurements in healthy kidneys produce realistic values for the reabsorption fraction. The 3-compartment model is the most attractive alternative, since it more accurately models the kidney physiology and allows to measure the glomerular filtration rate from a fit to the kidney curve alone.

11:54 461. MR Elastography of the Kidneys: Preliminary Results Sudhakar Kundapur Venkatesh1, 2, Meng Yin1, Roger C. Grimm1, Phillip J. Rossman1, Jun Chen1, Armando Manduca1, Anthony J. Romano, 13, Richard L. Ehman1 1Mayo Clinic, Rochester, Minnesota, USA; 2NUS, Singapore, Singapore; 3Naval Research Laboratory, Washington, District Of Columbia, USA

A method for applying MR Elastography to quantitatively assess the mechanical stiffness of the human kidney in vivo was developed and tested in a series of volunteers. A large passive pneumatically-activated acoustic driver, placed against the posterior abdominal wall in the supine position was found to provide excellent shear wave illumination of the kidneys. Elastograms were successfully obtained in all three orthogonal planes in 25 seconds of acquisition time for each cross-sectional image. The study results provide a practical protocol for further studies of renal MRE and initial normative values for the stiffness of renal parenchyma in humans in vivo.

12:06 462. Retrospective Respiratory Triggering for 2D Abdominal Perfusion MRI Ulrike Attenberger1, Steven Sourbron1, Henrik Michaely2, Mike Notohamiprodjio1, Maximilian Reiser1, Christian Glaser1, Karin Herrmann1 1Ludwig-Maximilians-University, Munich, Germany; 2University of Heidelberg, Mannheim, Germany

Quantification of renal blood flow and glomerular filtration rate is possible with MRI measurements. As acquisition times of several minutes are needed an alternative strategy is required to compensate the effect of respiratory motion. We used a retrospective triggering approach in this study which might be especially promising in critically ill patients.The aim of this study was a first evaluation of this method using patient data.9 consecutive patients (4 women, 5 men; mean age 59) underwent renal perfusion measurements after intravenous injection of 7 ml Gd-BOPTA (Multihance®, Bracco) at 4 ml/s at 3.0T (Magnetom Tim Trio; Siemens Medical Solutions, Erlangen, Germany). Data were acquired with a 2D Saturation-recovery TurboFLASH sequence measuring 5 slices (4 coronal, 1 axial) with a temporal resolution of 0.9s and a pixel size of 2.3 mm (slice thickness 8mm, FA 8 , TI 71ms, TR 177ms, TE 0.93ms, matrix 192x176).A 4-pixel region-of-interest (ROI) was drawn manually in the lumen of the aorta to measure the Arterial Input Function (AIF). For the measurement of the triggering signal, a rectangular triggering ROI was placed at the interface between tissue and air on the axial slice. . In order to test the dependence of the results on the precise choice of the triggering ROI, the analysis was repeated for three widely differing ROIs at the tissue-to-air interface. Our results show that without triggering the image is blurred due to the combined influence of data measured during in- and expiration. After triggering, the contours are sharper and the image has a stronger contrast. The results show that retrospective respiratory triggering is a feasible approach to correct for breathing motion in the quantification of renal functional parameters using a two-compartment model.

12:18 463. Adaptive 2D Centric View Ordering for Fast Abdominal Imaging Ersin Bayram1, Charles R. Michelich1, Anthony T. Vu1, James H. Akao1, Shaorong Chang1, Sanjay M. Joshi1, Reed F. Busse2, Anja C. S. Brau3, Philip J. Beatty3, Lloyd Estkowski1 1GE Healthcare, Waukesha, Wisconsin, USA; 2GE Healthcare, Madison, Wisconsin, USA; 3GE Healthcare, Menlo Park, California , USA

Resolution and coverage in abdominal MRI are largely limited by the breath-hold scan times. 2D parallel imaging can be utilized to address this issue. The potential for breath-hold mismatch between the external calibration scan and the accelerated scan makes auto-calibrated techniques more appealing, at the expense of reduced net acceleration. The scan time penalty becomes even more evident with magnetization-prepared fat suppression approaches in which a segmented view ordering scheme must be employed. Segmentation forces the number of total views along the segmentation direction to be an integer multiple of the segment size and also to remain constant from one kx-ky or kx-kz plane to the next. This restriction forces the acquisition to fall on a separable ky-kz grid as shown in Fig.1A. An adaptive centric view ordering scheme is proposed that supports more efficient sampling patterns including non-separable grids as well as k-space corner removal

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CLINICAL CATEGORICAL COURSE Imaging CNS Autoimmune Diseases Room 701 A 10:30 – 12:30 Chairs: John D. Port and Mark A. van Buchem

Educational Objectives: Upon completion of this course, participants should be able to:

• Describe the common autoimmune etiologies and pathogenesis of these diverse and clinically challenging disease entities; • List the different imaging findings present for each entity; • Recognize the challenges, limitations, and pitfalls of current imaging techniques with respect to these diverse disease entities; and • Discuss future potential MR imaging techniques for the diagnosis of these entities.

10:30 State-of-the-Art Imaging of the Autoimmune Vasculidities Pia C. Maly Sundgren 10:55 Primary Demyelinating Diseases Vincent Dousset 11:20 State-of-the-Art Imaging of Neurosarcoidosis

J. Keith Smith 11:45 Paraneoplastic Diseases of the Brain Marco Essig 12:10 Discussion

MRA: Clinical Studies Room 701 B 10:30-12:30 Chairs: John Huston and Ona Wu

10:30 464. Simultaneous Acquisition of MR Angiography and Venography (MRAV) Yiping P. Du1, Zhaoyang Jin2, 3 1University of Colorado Denver School of Medicine, Aurora, Colorado , USA; 2Hangzhou Dianzi University, Hangzhou, People's Republic of China; 3Zhejiang University, Hangzhou, People's Republic of China

A dual-echo pulse sequence has been developed for simultaneous acquisition of MR angiography and venography (MRAV). The acquisition of a second echo for susceptibility-weighted imaging (SWI) based MR venography (MRV) is added to the conventional 3D time-of-flight MR angiography (MRA) pulse sequence. Using this dual-echo acquisition approach, the MRV data can be acquired without increasing the TR and, therefore, scan time in routine MRA scans at 3 Tesla. Brain scans have been used to demonstrate the feasibility of simultaneous acquisition of MRAV.

10:42 465. PC HYPR Flow: A Technique for Rapid Imaging of Contrast Dynamics Julia V. Velikina1, Kevin Johnson, Yijing Wu, Patrick Turski, Charles Mistretta 1University of Wisconsin - Madison, Madison, Wisconsin, USA

We propose a novel method, PC HYPR Flow, that combines the benefits of rapid three dimensional radial acquisition and HYPR reconstruction to obtain a time series of 3D images with isotropic submillimeter spatial resolution, subsecond temporal resolution, and high SNR. PC HYPR Flow consists of a contrast enhanced exam immediately followed by a phase contrast scan that is used to constrain the reconstruction of the time series and to provide additional physiological information about the hemodynamics. We explore the feasibility of the new technique in a series of in vivo exams in healthy subjects and patients with brain arterio-venous malformations. The temporal resolution of PC HYPR Flow is studied in phantom experiments.

10:54 466. Conjugate-Gradient HYPR of Intracranial AVMs Hyun Jeong1, Timothy John Carroll1, 2, Christopher Getch1, Christpher S. Eddleman1, Mark A. Griswold3 1Northwestern University, Chicago, Illinois, USA; 2Chicago , Illinois, USA; 3Case Western Reserve University, Cleveland, Ohio, USA

HYPR increases SNR of MRA images, but also introduces cross-talk and artifacts in the images. Conjugate-gradient HYPR is an algorithm to iteratively correct the image errors resulting from HYPR. Temporal profiles of HYPR, CG HYPR, and MRA without HYPR were studied. The images were taken from angiographically confirmed AVM patients, which were correlated with XRA.

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11:06 467. Hybrid-MRA: A New Non-Contrast MRA Technique with Dual-Echo 3D Gradient Echo Sequence in Combination of Time-Of-Flight and Flow-Sensitive Black-Blood Tokunori Kimura1, Masato Ikedo1, Syuhei Takemoto2 1Toshiba Medical Systems, Otawara, Japan; 2Toshiba Medical Systems, Tokyo, Japan

We proposed a novel MR angiography technique named Hybrid-MRA (HMRA) with 3D dual-echo gradient echo sequence combined Time-of-Flight (TOF) with Flow-Sensitive Black-Blood (FSBB) employed flow dephasing gradients. HMRA images were simply obtained with the maximum intensity projection (MIP) after weighted subtraction of original images of TOF and FSBB with or without high-pass filtering. We demonstrated that slower and narrower vessels such as collateral were visualized better by HMRA than the standard TOF-MRA with and without MTC pulses. HMRA technique will provide clinically additional information about slower vessels which is hard to be visualized by current TOF-MRA.

11:18 468. CE-MRA and MR Velocimetry in the Determination of Hemodynamic Forces in Longitudinal Studies of Intracranial Aneurysm Growth David Saloner1, 2, Loic Boussel1, Vitaliy L. Rayz1, Joseph R. Leach1, Alastair J. Martin3, Gabriel Acevedo-Bolton1, Randall T. Higashida3, Michael T. Lawton3, William L. Young3 1VA Medical Center, San Francisco, USA; 2University of California San Francisco, San Francisco, USA; 3University of California San Francisco, USA

CE-MRA was used to monitor aneurysm growth over time in patients with untreated aneurysms. Computational Fluid Dynamics models were constructed using the CE-MRA boundary conditions together with values of inlet and outlet flow as measured by PC-MRI. Serial studies were co-registered using internal fiducials. Areas of lumenal growth were correlated with hemodynamic descriptors extracted from the numerical simulations, and increased growth was noted at locations of low wall shear stress. This study demonstrates the ability to base patient-specific determination of hemodynamic factors on MR methods, and to correlate those factors with volume changes as assessed by MRA.

11:30 469. Intracranial 4D MRA: Evaluation of Additional View Sharing for Improved Temporal and Isotropic Spatial Resolution at 3.0 T Dariusch Reza Hadizadeh1, Jürgen Gieseke1, 2, Guido Kukuk1, Liesbeth Geerts2, Gabriele Beck2, Hans Heinz Schild1, Winfried Albert Willinek1 1University of Bonn, Bonn, Germany; 2Philips Medical Systems, Best, Netherlands

Adequate diagnosis and treatment of cerebral arteriovenous malformations (cAVM) requires detailed characterization of both angioarchitecture and hemodynamics. In previous studies, a combination of CENTRA, Keyhole, parallel imaging (SENSE) and partial Fourier allowed for high temporal resolution 4D contrast-enhanced MRA at 3.0T. The addition of view sharing for further acceleration and increase of spatial resolution was evaluated in 11 subjects including 2 patients with cAVM and DSA correlation. 4D CEMRA with additional view sharing at 3.0T allowed for further increase in temporal and spatial resolution and clear depiction of arterial and venous phases without additional artefacts or decline in image quality.

11:42 470. In-Vivo visualization and Analysis of 3D Hemodynamics in Cerebral Aneurysms with Flow-Sensitized 4D MR Imaging at 3T Stephan Meckel1, Aurélien F. Stalder2, Francesco Santini1, Ernst-Wilhelm Radü1, Klaus Scheffler1, Michael Markl2, Stephan G. Wetzel1 1University Hospital Basel, Basel, Switzerland; 2University Hospital Freiburg, Freiburg, Germany

Blood-flow patterns and wall shear stress (WSS) are assumed to play a major role in development and rupture of cerebral aneurysms. To date, these hemodynamic aspects have been extensively studied in-vitro using geometric realistic aneurysm models. The purpose of this study was to evaluate the feasibility of in-vivo flow-sensitized 4D MR imaging for the visualization and quantification of intra-aneurismal hemodynamics. 5 cerebral aneurysms, differing in size, shape and location, were examined using flow-sensitized 4D MR imaging at 3T in 3 patients. 3D postprocessing was performed with a dedicated, commercially available, software package combined with an in-house software tool. This included quantification of flow-velocities, visualization of time-resolved 2D vector graphs and 3D particle traces, vortex core localization, and WSS estimations from 3D velocity fields. Flow patterns were analyzed in relation to aneurysm geometry and aspect ratio (aneurysm depth/neck width). Strength, spatial and temporal evolution of vortical flow patterns differed markedly among all aneurysms. Particularly unstable vortical flow was demonstrated in a wide-necked parophthalmic ICA aneurysm (high aspect ratio). Relatively stable vortical flow was observed in aneurysms with lower aspect ratio. Except for a wide-necked cavernous ICA aneurysm (low aspect ratio), WSS was reduced in all aneurysms relative to the parent artery and showed a high spatial variation. In conclusion, in-vivo flow-sensitized 4D MR imaging can be applied to visualize and quantify blood flow patterns and to estimate WSS inside cerebral aneurysms. Flow patterns, distribution of flow velocities, and WSS seem to be determined by the vascular geometry of the aneurysm.

11:54 471. Evaluation of Intracranial Aneurysms with 7T Versus 1.5T MR Angiography Christoph Moenninghoff1, 2, Stefan Maderwald1, 2, Jens M. Theysohn1, 2, Susanne C. Ladd1, 2, Oliver Kraff1, 2, Mark E. Ladd1, 2, Elke R. Gizewski1, 2, Michael Forsting1, 2, Isabel Wanke1, 2 1University Hospital Essen, Essen, Germany; 2University Duisburg-Essen, Essen, Germany

Time-of-Flight (TOF) MR angiography is the most frequently used MR technique for assessment of intracranial aneurysms. Highfield MRI is known to improve vessel-to-tissue contrast of TOF MRA. This is the first prospective study including ten patients with twelve unruptured intracranial aneurysms examined by 7T, 1.5T TOF MRA and conventional angiography. Two blinded neuroradiologists rated the image quality of aneurysms. 7T TOF MRA superiorly depicted the aneurysm dome in 58% and the aneurysm neck in 50% of twelve aneurysms in comparison to 1.5T MRA. New head coils and parallel imaging techniques are expected to further improve image quality of TOF MRA.

12:06 472. Imaging of Lenticulostriate Arteries at 7 Tesla Jaco J.M. Zwanenburg1, Fredy Visser2, Taro Takahara1, Jeroen Hendrikse1, Peter Luijten1 1University Medical Center Utrecht, Utrecht, Netherlands; 2Philips Medical Systems, Best, Netherlands

This work shows that it is possible to visualize the lenticulostriate arteries (diameters 0.3 - 0.7 mm) using MRI at 7 Tesla, without a contrast agent. A straightforward time-of-flight sequence was used, with optimized planning to maximize the inflow effect and decrease the saturation of the blood in the distal internal carotid artery.

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12:18 473. High Resolution Intracranial Time-Of-Flight (TOF) MRA at 7T Using Autocalibrating Parallel Imaging Cornelius von Morze1, 2, Derk D. Purcell1, Suchandrima Banerjee1, 2, Duan Xu1, Douglas AC Kelley, Pratik Mukherjee1, 2, Sharmila Majumdar1, 2, Daniel B. Vigneron1, 2 1UCSF, San Francisco, USA; 2UCSF/UCB Joint Graduate Group in Bioengineering, San Francisco, USA

Higher spatial resolution intracranial 3D TOF MRA is possible at higher field strengths, due to the increased CNR. However, at very high fields, spatial resolution is limited by the acquisition time required for sequential phase encoding. We applied a custom autocalibrating GRAPPA-based reconstruction to 7T TOF MRA studies of normal volunteers and patients with vascular disease, in order to obtain very high resolution (0.146mm3) images within a reasonable scan time. This technique produced high resolution MRA studies free from artifacts in all subjects, and correctly identified vascular pathology in patients.

New Cellular & Molecular Imaging Agents Room 713 A/B 10:30-12:30 Chairs: Mike Modo and A. Dean Sherry

10:30 474. Dual Transfer of Gene and MR Contrast Agent Into Stem-Progenitor Cells for in Vivo MR Imaging of Stem Cell-Mediated Gene Therapy Bensheng Qiu1, Xiangcan Zhan2, Piper Treuting1, Charles W. Frevert1, Xiaoming Yang1 1University of Washington, Seattle, Washington, USA; 2Johns Hopkins University School of Medicine, Baltimore, Maryland, USA

Atherosclerotic cardiovascular disease is a unique illness that produces diffuse and multiple atherosclerotic lesions in nearly all arteries of the body. Hematopoietic stem-progenitor cells circulate in the blood system, flow through the entire body, and thus home to wherever atherosclerotic plaques exist. Transfer of therapeutic genes into hematopoietic stem-progenitor cells prior to their transplantation to the body may enable to explore a stem cell-mediated target-specific delivery of therapeutic genes. This study focused on validation of the feasibility to co-transfer a reporter gene and an MR contrast agent into bone marrow (BM) cells in vitro and in vivo, which should establish the groundwork to develop target-specific molecular MR imaging of stem-progenitor cell-mediated gene therapy of atherosclerotic cardiovascular diseases.

10:42 475. Hyperpolarized 3He MRI to Detect Lung Metastases Targeted by Magnetic Nanoparticles Tamara Branca1, Carola Leuschner2, Challa Kumar2, Boma Fubara3, Warren Warren1, Bastiaan Driehuys3 1Duke University, Durham, North Carolina, USA; 2Louisiana State University, Baton Rouge, Louisiana, USA; 3Duke University Medical Center, Durham, North Carolina, USA

We demonstrate a novel method to detect the accumulation of targeted nanoparticles in lung cancer metastases by using 3He MRI. A BALB/c mouse was inoculated with MDA-MB-435S human breast cancer cells, which after 60 days resulted in metastatic cells in the lungs. The mouse was injected 24 hr prior to imaging with super paramagnetic iron oxide nanoparticles (SPIONs) that were conjugated with the lutenizing hormone releasing hormone (LHRH) whose receptors are over-expressed by breast cancer cells. Hyperpolarized 3He lung images made at TE=4 ms contained numerous signal voids that were shown histologically to be regions of SPION accumulation.

10:54 476. Charged Nanoparticles for MRI of the Basement Membrane Kevin M. Bennett1, Hua Zhou2, James P. Sumner1, Stephen J. Dodd1, Nadia Bouraoud1, Kent Doi2, Robert A. Star2, Alan P. Koretsky3 1National Institute of Neurological Disease and Stroke, Bethesda, Maryland, USA; 2National Institute of Diabetes and Digestive and Kidney Disease, Bethesda, Maryland, USA; 3National Institutes of Neurological Disease and Stroke, Bethesda, Maryland, USA

In this work, a method for noninvasively detecting the integrity of the basement membrane, based on the delivery of cationic iron-oxide nanoparticles, was developed. Particles accumulate due to the highly negative charge of the basement membrane. After systemic injection of cationic (CF) or native (NF) ferritin, ex vivo and in vivo MRI showed selective accumulation of CF in kidney glomeruli. . Immuno-fluorescence and electron microscopy confirmed that CF was localized to the glomerular basement membrane (GBM). In a model of GBM breakdown, MRI showed reduced single glomerular accumulation of CF, but a diffuse accumulation of CF in the kidney cortex

11:06 477. An MRI Contrast Agent Targeted for Activated Platelets Allows Detection of Thrombosis and Thrombolysis in an in Vivo Mouse Model Dominik von Elverfeldt1, Constantin von zur Muhlen1, Julia Moeller1, Dominik Paul1, Anne Katrin Becker1, Irene Neudorfer1, C Bode1, K Peter2, Juergen Hennig1 1University Hospital Freiburg, Freiburg, Germany; 2Baker Heart Research Institute, Melbourne, Australia

To allow in vivo imaging of activated platelets in wall adherent, non-occlusive carotid thrombosis, we applied an MRI contrast agent consisting of MPIOs and single-chain antibodies designed to selectively recognize ligand-induced binding sites of the activated GPIIb/IIIa-receptor. We were able to image wall adherent thrombosis and directly monitored the success of thrombolytic treatment. The contrast agent represents a novel and unique technique that allows detection and quantification of thrombi and can be used to monitor success of thrombolytic therapy. These properties are a promising basis for further development of MPIO-based contrast agents for the potential detection of vulnerable atherosclerotic plaques.

11:18 478. MRI-Invisible Pathology in Murine Cerebral Malaria Revealed by a Novel Contrast Agent Recognising Activated Platelet Glycoprotein IIb/IIIa Receptors Nicola Sibson1, Constantin von zur Mühlen1, 2, Karlheinz Peter3, Robin Choudhury1, George Grau4, Christoph Bode2, Sandra Campbell1, Daniel Anthony1 1University of Oxford, Oxford, UK; 2University Hospital Freiburg, Germany; 3Baker Heart Institute, Melbourne, Australia; 4The University of Sydney, Australia

Neurological MRI is often limited in that it reflects downstream injury, and it cannot assess disease activity. Molecular imaging has the potential to overcome these limitations. Human and murine cerebral malaria are associated with increased cytokines in the brain and adherence of platelets to the microvasculature. Here, we demonstrate that platelet accumulation in the brain microvasculature can be detected with MRI using a novel contrast agent targeted at ligand-induced binding sites on activated platelet GPIIb/IIIa receptors at a time when the pathology is otherwise undetectable. These results highlight the potential of targeted contrast agents for diagnostic, mechanistic and therapeutic studies.

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11:30 479. Novel Single Layer MR-Visible Alginate Microcapsules for Visualization and Immunoprotection of Hepatocytes Thomas Link1, 2, Partha Hota1, Brad P. Barnett1, Chris M. Long1, 2, Segun Bernard1, Piotr Walczak1, Robert Liddell1, Aravind Arepally1, Jeff Bulte1 1Johns Hopkins Medical Institution, Baltimore, Maryland, USA; 2Johns Hopkins University, Baltimore, Maryland, USA

Feridex was incorporated into novel single layer barium cross-linked alginate microcapsules to create MR-visible magnetocapsules for immunoprotection of hepatocytes. Capsule MRI properties were assessed using gelatin phantoms and cell viability was assessed in vitro. Results indicate that capsule permeability and cell viability were similar to standard alginate-PLL-alginate magnetocapsules. MRI properties were also similar, demonstrating their potential for use in vivo for treatment of fulminant liver failure.

11:42 480. Lipid-Coated Silica Nanoparticles; a Contrast Agent Platform for Multimodality Molecular Imaging Rolf Koole1, Matti M. van Schooneveld1, Jan Hilhorst1, Karolien Castermans2, Gustav J. Strijkers3, Celso de Mello Donegá1, Daniel Vanmaekelbergh1, Arjan W. Griffioen2, Klaas Nicolay3, Zahi A. Fayad4, Andries Meijerink1, Willem J. M. Mulder4 1Utrecht University, Utrecht, Netherlands; 2Maastricht University, Maastricht, Netherlands; 3Eindhoven University of Technology, Eindhoven, Netherlands; 4Mount Sinai School of Medicine, New York, USA

A novel platform for multimodal contrast agents is presented, based on a hydrophobic silica particle with a lipidic coating. It describes a general method for making silica particles bio-applicable. Here, we used quantum dots incorporated in silica particles, coated by a layer of paramagnetic, pegylated, and bio-functional lipids. The particles are highly target-specific, and can be used for both fluorescence imaging and MRI.

11:54 481. Improved Molecular Imaging of Angiogenesis by Synergistic Targeting of Liposomal Contrast Agent to the Receptors α ν β 3 Integrin and Galectin-1 Ewelina Kluza1, Daisy van der Schaft1, Willem Mulder2, Arjan Griffioen3, Gustav J. Strijkers1, Klaas Nicolay1 1Eindhoven University of Technology, Eindhoven, Netherlands; 2Mount Sinai School of Medicine, New York, USA; 3Maastricht University & The University Hospital Maastricht, Maastricht, Netherlands

Tumor angiogenesis has become an important target in tumor diagnostics and anti-tumor therapy. We propose targeting of two receptor populations:α vβ

3integrin and Galectin-1 in order to increase the delivery of the paramagnetic contrast agent to activated endothelial cells. Two ligands, cyclic RGD peptide and Anginex, were conjugated to paramagnetic/fluorescent liposomes. Fluorescence microscopy, fluorescence intensity measurements and T1 relaxation time measurements showed that the uptake of liposomal contrast agent by angiogenic endothelial cells was increased by simultaneous targeting of two receptor populations. This appeared to be the most effective by conjugating two different ligands to the same particle.

12:06 482. Urokinase Plasminogen Activator Receptor (UPAR) Targeted Multifunctional Magnetic Nanoparticles for in Vivo Molecular MRI of Pancreatic Cancers Hui Mao1, 2, Lily Yang1, 2, Xianghong Peng2, Chunchun Ni3, Andrew Y. Wang4, Shuming Nie1, 2, Xiaoxia Wang1 1Emory University School of Medicine, Atlanta, USA; 2Emory University, Atlanta, USA; 3Emory University School of Medicine, Atlanta, Georgia, USA; 4Ocean NanoTech LLC, Fayetteville, USA

We are reporting an novel nanoparticle based receptor targeted imaging agent for imaging pancreatic cancer in the animal model

12:18 483. In Vivo and in Vitro Mapping of the Radio Frequency Magnetic Field Generated by Microsized Resonators in a 3T Clinical MRI Scanner Razvan Ciocan1, Robert E. Lenkinski1, Jonathan Bernstein2, Robert Marquis1, Alex Ivanishev1, Aya Matsui1, Fotini Kourtelidis1, Mirela Bancu2, Jeffrey T. Borenstein2, John V. Frangioni1 1Beth Israel Medical Center, Boston, Massachusetts, USA; 2The Charles Stark Draper Laboratory, Boston, Massachusetts, USA

Micro-sized resonators can provide a way of individual cell tracking in a clinical MRI. In this work we demonstrate that magnetic field generated by such devices that have the dimensions 300, 500, and 1000 microns, respectively, can be mapped in experiments performed in a clinical 3T scanner.

Image Simulation & Analysis Room 715 A/B 10:30-12:30 Chairs: Christos Davatzikos and John G. Sled

10:30 484. Inverse Consistent Geometric Flow Based Nonlinear Registration Driven by Mutual Information Guozhi Tao1, Renjie He1, Sushmita Datta1, Ponnada A. Narayana1 1University of Texas Medical School at Houston, Houston, Texas, USA

A diffeomorphic registration technique that explicitly includes inverse consistent constraint is developed and applied on normal human brain. The maximum inverse consistency error with our method is less than 0.07 voxels. This is ten times smaller than the recently reported values.

10:42 485. iMRI Data Repository for Validation of Brain Non-Rigid Registration Algorithms Neculai Archip1, Ion-Florin Talos1 1Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA

This paper presents the development of a freely accessible, on-line repository of pre-and intra-operative MR-images derived from patients with hemispheric brain tumors, to serve as a validation platform for non-rigid registration algorithms.

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10:54 486. An Automatic Computational Method for the Measurement of Amyloid Plaque Load in the APP Transgenic Mouse Brain George Iordanescu1, 2, Palamadai Venkatasubramanian1, 2, Alice M. Wyrwicz1, 2 1ENH Research Institute, Evanston, Illinois, USA; 2Northwestern University Feinberg School of Medicine, Evanston, Illinois, USA

We present a novel automatic method based on simulated flooding and data Laplacian to segment the AD plaques in mouse MR brain images, and show how the method can be used for a detailed analysis of plaque characteristics. The segmentation map can be used to asses individual plaques (average profile, volume, intensity variability grade), to compute the plaques load or the plaques distribution for specific brain structures. Since no assumptions are made on the plaques shape or size, the proposed method can be used to analyze data for different AD stages or mouse strains, where plaques variability should be expected.

11:06 487. Improved Accuracy and Smoothed Lipid Content by Maximum a Posteriori Estimation in CHESS Ratio Images Wilbur C. K. Wong1, David Johnson2, Chris Flask3, Paul Ernsberger2, David Wilson2, 3 1The Hong Kong University of Science & Technology, Kowloon, Hong Kong; 2Case Western Reserve University, Cleveland, Ohio, USA; 3University Hospitals of Cleveland, Cleveland, Ohio, USA

We are using MR to quantify fat depots (e.g., visceral, subcutaneous, hepatic, muscular) so as to determine the role of genetic, environmental, and therapeutic factors on lipid accumulation, metabolism, and disease states. In this report, we studied lean spontaneously hypertensive rats (SHRs), a genetic variant prone to obesity (SHROBs), and animals given a high fat, high sucrose diet creating dietary obese animals (SHR-DOs). Animals were imaged with and without CHESS water-suppression. Ratio images exactly compensate for receive coil sensitivity inhomogeneity and enable the creation of gray-scale based automated analysis. A ratio image model was created for measuring lipid content in subcutaneous and visceral depots. We analyzed the statistical property of the ratio of two noisy signals and developed a maximum a posteriori (MAP) estimate of the lipid content in each voxel. We simulated the partial volume effect in a digital phantom with known fat content in each voxel. Even if relaxivities were corrected, ratio images overestimated the true volume of fat by 23%. In a cohort of rats, the MAP correction reduced visceral adipose tissue volume by 20%. We identified obesity phenotypes and characterized this model of metabolic syndrome.

11:18 488. Quantitative Contrast Enhancement Maps of the Carotid Atherosclerotic Plaque In-Vivo: Methodology and Clinical Assessment Niranjan Balu1, Vasily Yarnykh1, William Kerwin1, Jianming Cai2, Chun Yuan1 1University of Washington, Seattle, USA; 2Chinese PLA General Hospital, Beijing, People's Republic of China

Contrast enhancement (CE) patterns of the carotid atherosclerotic plaque are indicative of plaque neovasculature and inflammation. Therefore quantitative CE information from black-blood CE-MRI may provide additional markers of plaque vulnerability. We demonstrate a fast, semi-automated method to obtain quantitative CE maps (QCEM) of the carotid plaque in-vivo. Luminal surface, adventitial surface, plaque shoulder and core subregions were automatically segmented for their respective QCEM. Group histograms and histogram statistics from subregion QCEM of 24 patients were compared between plaques of high and low plaque burden. Larger plaque locations showed significantly higher core and shoulder enhancement indicating possible inflammation/neovasculature in these regions.

11:30 489. Efficient MRI Simulation Via Integration of the Signal Equation Over Triangulated Surfaces Luca Antiga1, David Andrew Steinman2 1Mario Negri Institute for Pharmacological Research, Bergamo, Italy; 2University of Toronto, Toronto, Canada

MRI simulation of anatomically realistic objects can be inefficient owing to the need to discretize these objects volumetrically. Here we present an efficient simulation technique based on integrating the MRI signal equation over a surface rather than volume discretization.

11:42 490. Quantitative Magnetization Transfer Imaging Using Balanced SSFP Monika Gloor1, Klaus Scheffler1, Oliver Bieri1 1University Hospital / University of Basel, Basel, Switzerland

In tissues, the signal of balanced steady-state free precession (bSSFP) is considerably reduced from magnetization transfer (MT). An extended bSSFP signal equation is derived, based on a binary spin-bath model including MT effects. Using this new bSSFP signal model, quantitative MT model parameters such as the fractional pool size, corresponding magnetization exchange rates, and relaxation times are estimated in human brain. The results show high correlation with the ones from standard methods, but benefit from bSSFP’s short acquisition times and high signal-to-noise ratios. This allows the acquisition of isotropic high resolution quantitative MT maps within clinically feasible acquisition times.

11:54 491. Optimal Sample Parameter Estimates from Phased Array Coil Data Utilizing Joint Bayesian Analysis James D. Quirk1, Alexander L. Sukstanskii1, G Larry Bretthorst1, Dmitriy A. Yablonskiy1, 2 1Washington University School of Medicine, St. Louis, Missouri, USA; 2Washington University, St. Louis, Missouri, USA

We demonstrate that joint Bayesian analysis of array coil data offers a "worry-free" method for obtaining optimal estimates of sample parameters. A theory predicting the parameter estimate uncertainty was developed and validated on simulated data. Comparisons between joint analysis and more traditional coil combination methods (e.g. sensitivity weighted, SOS) indicate that estimates from joint analysis have equivalent or superior precision and accuracy on phased and magnitude data, without the use of reference scans. Combining channels without the optimal weighting factor (signal amplitude over noise power) can corrupt the parameter estimation and produce inferior results to a single channel analysis.

12:06 492. Computer-Generated Abdominal Phantom for Evaluation of MR Estimation Techniques Christian Graff1, Eric Clarkson1, Eric K. Outwater1, Maria I. Altbach1 1University of Arizona, Tucson, Arizona , USA

Computer-generated phantoms provide a convenient way to evaluate MR parameter estimation algorithms. However, if the phantom data is significantly different from in vivo data, results from phantom studies may not be predictive of performance in vivo. We have constructed a computer-generated abdomen phantom which contains realistic models for parameter variability, coil sensitivities and other practical effects.

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12:18 493. A Flexible Software Phantom for Generating Realistic Dynamic Contrast-Enhanced MR Images of Abdominal Tumours Anita Banerji1, Angela Caunce1, Yvon Watson1, Chris Rose1, Giovanni Buonaccorsi1, Geoff Parker1 1The University of Manchester, Manchester, UK

The software phantom presented in this work generates synthetic images from known ground truth for use in the validation of post-acquisition image processing algorithms, for example registration techniques for DCE-MR time series. The design of the phantom is flexible allowing images for various different imaging scenarios and modalities to be produced. A range of synthetic data sets can be generated that are relevant to the image processing algorithm in order to test robustness, accuracy and precision. Example DCE-MR images with realistic anatomy based on in-vivo data sets are shown.

CLINICAL CATEGORICAL COURSE Shoulder Instability: Clinical Considerations and Imaging Needs? Room 717 A/B 10:30 – 12:30 Chair: Jürg Hodler

Educational Objectives: Upon completion of this course, participants should be able to:

• List clinical indications of shoulder instability; • Identify the imaging needs of the shoulder surgeon in the evaluation of patients with suspected shoulder pathology; • Identify the limitations of MRI in diagnosis of glenoid labrum pathology; • Explain the indications for shoulder MR arthrography; and • Describe the role of 3.0T MRI in evaluation of the glenoid labrum.

10:30 Post-Traumatic Shoulder Instability Diane L. Dahm 11:00 Conventional MRI in Evaluation of Shoulder Instability Hollis G. Potter 11:30 MR Arthrography in Evaluation of Shoulder Instability

Christian W. Pfirrmann 12:00 Discussion

HANDS-ON WORKSHOP 1 Neuro and Musculoskeletal Protocol Optimization Philips Medical Systems Room 709 10:30 – 12:30

Siemens Medical Solutions Room 711 10:30 – 12:30

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GOLD CORPORATE MEMBER LUNCHTIME SYMPOSIUM GE Healthcare Hall F 12:30 – 13:30

SPECIAL SYMPOSIUM Unsolved Problems and Unmet Needs Room 801 A/B 13:30 - 15:30 Chair: Daniel K. Sodickson

Finding the Best Probe and the Ideal Image 13:30 Proffered Abstract: An NIH Roadmap Initiative to Enhance Progress in Imaging Sciences by Facilitating the Supply of Molecular Imaging Probes Compositions Gary Griffiths 13:50 Proffered Abstract: Objective Comparison of Alternate Reconstruction Evaluation Strategies: An Unmet Need Feng Huang 14:10 Invited Talk: Sharing has its Benefits: Proposals for Reconstruction Evaluation Standards and Code/Data Sharing James G. Pipe B0 and the Body: Can we Quantify Fat from Fields and Fields from Fat? 14:30 Proffered Abstract: Can MRI Represent an Accurate Quantitative Tool for Assessing Fat Distribution in Obesity

Research? Hochun Harry Hu

14:50 Proffered Abstract: Anatomy-Specific B0 Shimming Strategies for Robust Clinical Imaging Heidi Ward 15:10 Invited Talk: Fat Quantification and Anatomy-Specific Shimming: Can We Put the Two Together? Scott B. Reeder

Cutting Edge Techniques for Body MRI Room 716 A/B 13:30-15:30 Chairs: Nandita Desouza and Winfried A. Willinek

13:30 494. Diffusion Tensor Imaging of in Vivo Human Kidney at 3 T : Robust Anisotropy Measurement in the Medulla Hersh Chandarana1, Elizabeth Hecht1, Bachir Taouli1, Eric Edward Sigmund1 1New York University, New York, New York, USA

Diffusion tensor imaging (DTI) was performed in the kidneys of several healthy volunteers at 3 T, using an echo-planar imaging (EPI) sequence. Using data from several breathhold acquisitions that were co-registered before processing to improve SNR, robust measures of mean diffusivity (MD) and fractional anisotropy (FA) were obtained in both the cortex and medulla. Medullary compartments were found to have significantly FA than the cortex, and the principal diffusion eigenvectors were clearly observed to display the expected radial tubular orientation in the medulla. This study shows the potential for FA and other DTI markers to probe renal microstructure and function.

13:42 495. Strategies for Reducing Respiratory Motion Artifacts in Quantitative Renal Perfusion Imaging with Arterial Spin Labeling Philip Martyn Robson1, Ananth J. Madhuranthakam2, Weiying Dai1, David C. Alsop1 1Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA; 2GE Healthcare, Boston, Massachusetts, USA

Quantitative perfusion imaging in the kidneys using arterial spin labeling (ASL) is of potential importance for imaging renal function without the use of gadolinium-based contrast agents. We evaluate strategies for reducing respiratory motion artifacts enabling successful application of ASL in the abdomen. Background suppression techniques used in ASL, breathing patterns, and retrospective sorting of acquired perfusion-weighted images are explored. A strategy is established for overcoming the problem of respiratory motion that is suitable for application to clinical populations. Imaging of volunteers is repeated both within the session and in a separate session to estimate the test-retest repeatability of quantitative renal perfusion imaging using ASL.

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13:54 496. Initial Experience with RF Shimming at 3T Using a Whole Body 8 Channel RF System Jo V. Hajnal1, Shaihan J. Malik1, David J. Larkman1, Declan O'Regan1, Kay Nehrke2, Ulrich Katscher2, Ingmar Graesslin2, Peter Börnert2 1Hammersmith Hospital, Imperial College London, London, UK; 2Philips Research Europe, Hamburg, Germany

We report initial experience with RF shimming on a clinical 3T scanner equipped with a whole body 8 channel transmit system. Three volunteers were studied. Transmit sensitivity was measured for each coil element on each subject using a multi TR method. Field echo pelvic imaging was then performed using independent drives on each coil optimised to produce a homogeneous transmit field and this was compared to a mode of operation with all elements driven as a single coil. Results showed improved uniformity in excitation, with reduction of regional signal dropout that is common in body imaging at 3T.

14:06 497. Dynamic Contrast Enhanced MRI Evaluation of Crohn's Disease Activity: A Histopathological Correlation Shonit Punwani1, 2, Manuel Rodriguez-Justo2, Alan Bainbridge1, Enrico De Vita1, 2, Rebecca Greenhalgh2, Steve Halligan1, 2, Stuart Taylor1, 2 1University College London, London, UK; 2University College London Hospital, London, UK

The aim of this study was to correlate in-vivo DCE-MRI parameters with histologically determined mural acute inflammatory change in small bowel resection specimens from patients with known ileal Crohn’s disease. In vivo DCE-MRI of disease affected bowel was performed pre-operation. Post surgical small bowel resection specimens were scanned to enable detailed imaging-histopathology matching. Histological sections were taken through the area of bowel corresponding to the DCE-MRI images and an acute inflammatory score (AIS) derived. AIS was inversely related to semi-quantitative DCE-MRI parameters of enhancement ratio (ERdyn) and slope of enhancement (SoE). This finding is consistent with the hypothesis of reduced blood flow contributing to histopathological changes in acute Crohn's disease of the small bowel.

14:18 498. Diffusion-Weighted Imaging During Acute Unilateral Ureteral Obstruction - Demonstration of the Necessity to Separate Diffusion and Microperfusion Contributions Tobias Binser1, Thomas M. Kessler1, Chris Boesch1, Peter Vermathen1, Harriet C. Thoeny1 1University & Inselspital Berne, Berne, Switzerland

The aim of this study was to determine whether DW MRI is able to detect changes in renal diffusion and microperfusion during acute unilateral ureteral obstruction in humans. The results with significantly decreased cortical and medullary perfusion fraction and significantly increased medullary ADC suggest that DW-MRI might provide information as to the degree of obstruction and might therefore help in the decision making of time point of therapeutic intervention. In addition, the results clearly demonstrate the validity and necessity to separate diffusion and microperfusion compartments, in order to prevent misleading findings and interpretations.

14:30 499. Evaluation of Acute Hepatic Ischemia in Rats Using 23Na and 1H Diffusion-Weighted MRI Paige Nicole Hopewell1, Navin Bansal1 1Indiana University School of Medicine, Indianapolis, Indiana, USA

Due to excessive motion artifact with ADC calculation from DWI, SQ and MQF 23NaMRI is superior for acute hepatic ischemia evaluation in rats.

14:42 500. Characterization of Focal Renal Masses Evaluated Only with DW Imaging and Non-Enhanced MR Sequences senta m. Berggruen1, dava Grundhoefer, jenny Huang, nancy Hammond1, paul Nikolaidis1, frank h. Miller1 1Northwestern University, Chicago, Illinois, USA

With the advent of nephrogenic systemic fibrosis (NSF), the new restrictions of gadolinium usage pose an altered approach to MR imaging and interpretation in certain patients. The purpose of this study was to evaluate the accuracy of non-gadolinium enhanced sequences, in conjunction with diffusion-weighted sequences, to differentiate benign from malignant renal lesions. Our preliminary study demonstrates that differentiation of benign from malignant renal lesions and accurate evaluation of renal masses is possible with non-gadolinium enhanced sequences, in conjunction with diffusion-weighted MR imaging. Our data supports that AML have restricted diffusion with lower mean ADC values than renal cell carcinomas.

14:54 501. Effect of Field Strength and Software on Apparent Diffusion Coefficient Measurements in Diffusion-Weighted Imaging of the Abdomen at 1.5 and 3 Tesla Adam Charles Braithwaite1, Brian M. Dale2, Daniel T. Boll1, Elmar M. Merkle1 1Duke University Medical Center, Durham, North Carolina, USA; 2Siemens Medical Solutions, Cary, North Carolina, USA

With the emergence of high field strength magnets used in clinical practice, it would be useful to determine if there is any difference in ADC measurements at 3 T compared to the standard 1.5 T. If ADC values are indeed independent of field strength, then the monitoring of tumor response to treatment can be performed at both 1.5 T and 3 T. Our study shows that ADC values in abdominal organs are stable over 5 months but are highly sensitive to changes in post processing or sequences such as those that can occur during routine software upgrades. Longitudinal studies will need to incorporate some calibration methods to properly compare data across such inevitable changes. The ADC values in some tissues, such as liver, are sensitive to changes in field strength. For those tissues care must be taken that follow-up studies are performed at the same field strength.

15:06 502. ROtated Slab Excitation (ROSE) for Reduced Foldover Artifacts in Coronal 3D Abdominal Imaging Anja C.S. Brau1, Ersin Bayram2, Manoj Saranathan3, Akira Kawashima4 1GE Healthcare, Menlo Park, California , USA; 2GE Healthcare, Waukesha, Wisconsin, USA; 3GE Healthcare, Rochester, Minnesota, USA; 4Mayo Clinic, Rochester, Minnesota, USA

Three-dimensional coronal abdominal imaging is frequently performed for hepatic and renal imaging applications. However, applying the phase-encoding gradient in the left/right direction renders the acquisition vulnerable to foldover aliasing artifacts that potentially obscure the anatomy of interest. This work demonstrates the utility of a rotated slab excitation (ROSE) scheme for 3D coronal abdominal imaging that significantly reduces the severity of foldover artifacts for improved anatomical visualization with minimal, if any, effect on scan time, spatial resolution, or other imaging parameters.

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15:18 503. MRI Monitoring of the Influence of US Contrast Agent Destruction for Local Delivery of a MRI Blood Pool Contrast Agent in the Rat Liver Nora Frulio1, Hervé Trillaud1, Omer Eker1, Roel Deckers1, Sebastien Lepreux2, Christophe Laurent3, Claire Corot4, Chrit Moonen1, bruno Quesson1 1Laboratory IMF, Bordeaux, France; 2CHU Pellegrin, Bordeaux, France; 3CHU Saint André, Bordeaux, France; 4Guerbet, Paris, France

The temporal evolution of T1 values in the liver of rats was measured by repetition of a look-locker MRI sequence, before and after intravenous co-administration of a blood pool MRI contrast agent (Vistarem®) and an ultrasound contrast agent (Sonovue®). These microbubbles were then destroyed by ultrasound in one group of animals. T1 values resulting from a fit of the MRI data for the group with ultrasound were systematically lower than those of the control group, indicative of a change of the interaction between Vistarem® and surrounding tissue due to ultrasonic microbubble destruction.

MRI of Multiple Sclerosis Room 701 A 13:30-15:30 Chairs: Nicola DeStefano and Charles R. G. Guttman

13:30 504. Pathological Basis of Dirty Appearing White Matter in Multiple Sclerosis: Insights from MRI and Histology Cornelia Laule1, Irene M. Vavasour1, Esther Leung1, David K. B. Li1, Piotr Kozlowski1, Anthony L. Traboulsee1, Joel Oger1, Alex L. MacKay1, G.R. Wayne Moore1 1University of British Columbia, Vancouver, Canada

The pathological basis of dirty-appearing white matter (DAWM) in MS is not known. 53 MS subjects were examined with T1, multi-echo T2 and magnetisation transfer (MT). 23 samples of formalin-fixed MS tissue were examined with multi-echo T2 and a wide variety of histological stains for axons, myelin lipids and proteins. DAWM in-vivo had reduced myelin water and MT ratio, and increased T2 and water content. Histological analysis suggests DAWM is the MRI equivalent of a region with selective reduction of myelin phospholipids detected by the MWF, but with a relative preservation of myelin proteins, as well as axons.

13:42 505. Addressing the Enigma of Invisible Pathology in MS: A Multimodal Approach to Characterize Diffusely Abnormal and Normal-Appearing White Matter Alexandra Seewann1, Hugo Vrenken2, Erwin Blezer3, Lars Boe2, Jonas Castelijns2, Chris Polman2, Petra Pouwels2, Frederik Barkhof2, Jeroen Geurts2 1VU University Medical center, Amsterdam, Netherlands; 2VU University Medical Center, Amsterdam, Netherlands; 3University Medical Center Utrecht, Utrecht, Netherlands

Extralesional, diffusely affected white matter (DAWM), as detected on conventional MRI, may also contribute to lesion burden and hence disability in multiple sclerosis patients (MS) patients. As the histopathological correlates of DAWM are unknown, the aim of this post-mortem study was to radiologically and histologically characterize tissue changes in DAWM as compared to normal-appearing WM (NAWM). Seventeen brain slices from 10 chronic MS patients were imaged with qualitative MRI at two different field strengths and with quantitative MRI. Regions of interest (ROIs) were correlated with histopathology.DAWM represents a separate pathological process, reflecting significantly abnormal quantitative MRI and histopathology measures.

13:54 506. MRI of Multiple Sclerosis with High Contrast Susceptibility-Weighting and Extreme Resolution T2-Weighting Amir Eissa1, Robert Marc Lebel1, Jeff Robert Korzan, Anna Edith Zavodni, Kenneth Gary Warren, Derek James Emery, Alan H. Wilman1 1University of Alberta, Edmonton, Canada

Patients with multiple sclerosis are imaged at 4.7 Tesla using T2-weighted fast spin echo with 0.19 cubic millimetre voxels, and susceptibility-weighted imaging with increased contrast. The phase images from susceptibility weighting reveal increased iron content in some lesions, while the T2-images show precise lesion boundaries.

14:06 507. Phase Imaging of Multiple Sclerosis at 7T Kathryn E. Hammond1, Daniel Pelletier, Meredith Metcalf, Radhika Srinivasan, Duan Xu, Doug A. Kelley, Daniel B. Vigneron, 1, Sarah J. Nelson, 1 1University of California San Francisco (UCSF) / Berkeley Joint Graduate Group in Bioengineering, San Francisco, California , USA

The phase of the MR signal is sensitive to magnetic susceptibility-shifted compounds such as iron and provides a new contrast mechanism for studying neurodegeneration. Gradient echo images of seventeen RRMS patients were acquired at 7T at a resolution of 195x260 microns. The phase images showed novel contrast in lesions in the deep medullary veins. The phase contrast was often focused at the lesion periphery, a region known to have iron-laden macrophages in acute plaques and non-heme iron deposits in chronic plaques. MS patients had significantly higher phase contrast in the basal ganglia than controls, suggesting increased iron deposition.

14:18 508. In Vivo Characterization of Cortical Lesions in Multiple Sclerosis by 7T MRI Caterina Mainero1, Andre van der Kouwe1, Thomas Benner1, Graham Wiggins1, Bruce R. Rosen1, R Philip Kinkel2 1Massachusetts General Hospital, Charlestown, Massachusetts, USA; 2Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA

Although the development of cortical lesions has emerged as a major component of disease progression in multiple sclerosis (MS), the study of such lesions is constrained by the technical limitations of currently available MR techniques. Recent data at ultra-high field (7 T) indicate the ability to visualize cortical structure in great detail, potentially improving the detection of cortical MS lesions. Our preliminary data show the ability of high field 7T MRI not only to detect but also to characterize cortical lesions heterogeneity in MS patients. Different type of cortical lesions might have different pathogenesis and impact on disease outcome.

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14:30 509. Indication of Oxidative Stress in Multiple Sclerosis Using Proton MR Spectroscopic Imaging at 7T Radhika Srinivasan1, Sarah Nelson1, Kathyrn Hammond1, Duan Xu1, Douglas Kelley2, Daniel B. Vigneron1, Daniel Pelletier1 1University of california, San Francisco, California , USA; 2GE Medical Systems, USA

Oxidative stress is believed to be one of the causes that can trigger neurodegeneration in MS. The GST supergene family that encodes for enzymes involved in GSH metabolism were differentially expressed in plaques and shown to affect long term prognosis in MS. Glutathione (GSH) is accessible for measurement using non-invasive proton spectroscopic imaging techniques. It is therefore possible to provide a metric for oxidative state and phenotype in MS. However, since GSH is present in low concentrations in the brain and overlaps with stronger resonances it is not visible at lower field strengths such as 3T. In this study we use the benefit of improved SNR and chemical shift dispersion at 7T to develop a spectral editing scheme for the unobstructed detection of GSH. Using this technique the concentration of GSH is evaluated in white and gray matter in MS and compared to normal subjects.

14:42 510. High Field MRI for Lesion Characterisation in Multiple Sclerosis Klaus Schmierer1, Po-Wah So2, David H. Miller1, Sebastian Brandner1, Harold G. Parkes1, Tarek A. Yousry1 1Institute of Neurology, UCL, London, UK; 2Imperial College London, Hammersmith Hospital Campus, London, UK

Multiple sclerosis (MS) affects central nervous system white matter (WM) and grey matter (GM). Unlike WM lesions (WML), GM lesions (GML) are rarely detected at 1.5T. In order to better characterise GML multimodal MRI (T1, T2, MTR, diffusion) was performed on post mortem MS brain at 9.4T. In seven formalin fixed tissue blocks 11 GML and 9 WML were detected. All MR modalities provided useful measures to assess MS pathology. Contrast-to-noise was highest for both GML and WML at TE=24ms in T2 weighted acquisition. Formalin fixation (start, duration) were confounders of some MRI indices.

14:54 511. 7 Tesla Sodium MRI of Patients with Multiple Sclerosis: A Preliminary Study Guillaume Madelin1, Niels Oesingmann2, Glyn Johnson1, Sonia Nielles-Vallespin3, Bernd Stoeckel2, Enzo Barberi4, Robert Pinkerton4, Daniel Sodickson1, Robert I. Grossman1, Matilde Inglese1 1New York University, New York, New York, USA; 2Siemens Medical Solutions, New York, New York, USA; 3Siemens AG, Erlangen, Germany; 4XLR imaging Inc, London, Canada

Multiple Sclerosis (MS) is a multi-focal, demyelinating disease with involvement of neurons and axons. Pathological and imaging studies have shown that neuro-axonal loss occurs from disease onset, and that it correlates with disability. There is increasing evidence that the intra-axonal accumulation of sodium ions may contribute to degeneration. Sodium MRI (23Na MRI) provides an indicator of cellular and metabolic integrity. The low sensitivity and spatial resolution of 23Na MRI make higher field strengths desirable to improve this imaging modality. The aim of this study was to optimize 23Na MRI at 7T and investigate its feasibility to study patients with MS.

15:06 512. Magnetization Transfer Ratio Imaging in Multiple Sclerosis – a Comparison of 3D Balanced Steady-State Free Precession and 2D Gradient Echo Sequences in Clinical Studies Jochen G. Hirsch1, 2, Oliver Bieri1, Klaus Scheffler1, Alain Thoeni1, Ernst-Wilhelm Radue1, Ludwig Kappos1, Achim Gass1 1University Hospital Basel, Basel, Switzerland

There is great need for techniques, that quantitatively assess subtle tissue changes beyond the gross pathology in multiple sclerosis. We evaluated a new 3D-bSSFP MTR protocol yielding maximal sensitivity to MT in human brain. We compared this 3D-bSSFP with the commonly used 2D-GRE approach in a clinical setup, and evaluated the advantages of bSSFP in a quantitative study on 20 MS patients. Protocols were adjusted to similar acquisition times while using optimized sequence settings for both approaches. Higher, and esp. isotropic resolution, whole brain coverage, and stronger grey-white matter MTR contrast turned out to be the important advantages of 3D-bSSFP.

15:18 513. Tract-Based Spatial Statistics Shows Lower FA in the Fornices of Early MS Patients Stefan Dirk Roosendaal1, Jeroen J.G. Geurts1, Hugo Vrenken, Keith S. Cover, Jonas A. Castelijns1, Petra J.W. Pouwels, Frederik Barkhof1 1MS Center, Amsterdam, Netherlands

With the recently developed method Tract-Based Spatial Statistics, DTI measures of white matter can be compared voxelwise. This tool was used on DTI data of 31 patients with Multiple Slerosis and 31 age-matched healthy controls. In our study, which is one of the first to use TBSS in MS, we found that MS patients have areas of lower FA, not only in the WM commonly affected by lesions, but also more specifically in structures involved in memory processing, like the fornices and the hippocampus. These areas were found to be already affected in the early stages of the disease.

The Great Wall Room 701 B 13:30-15:30 Chairs: Chun Yuan and Jie Zheng

13:30 514. In Vivo MR Imaging of Endothelial VCAM-1 Expression in a Mouse Model of Both Stable and Vulnerable Atherosclerotic Plaque Leonie Elisabeth Maria Paulis1, Glenda Sibylle van Bochove1, Dolf Segers2, Willem J. Mulder3, Grietje Molema4, Rob Krams5, Gustav J. Strijkers1, Klaas Nicolay1 1Eindhoven University of Technology, Eindhoven, Netherlands; 2Erasmus University Medical Center, Rotterdam, Netherlands; 3Mount Sinai School of Medicine, New York, USA; 4University Medical Center Groningen, Groningen, Netherlands; 5London Imperial College, London, UK

In this study the possibilities of MR-imaging to in vivo visualize the expression of VCAM-1 on vascular endothelium were explored in a mouse model where stable and vulnerable plaques are induced in the right carotid artery. This approach is challenging, because the contrast agents’ location will be restricted to one layer of cells. Paramagnetic anti-mouse VCAM-1 liposomes were designed that showed in vitro specificity for VCAM-1. Fluorescence microscopy showed in vivo targeting of endothelial VCAM-1 by anti-VCAM-1 liposomes. The strongest in vivo MRI signal enhancement by these liposomes was observed in stable plaques, but the effect did not reach significance.

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13:42 515. Contrast-Enhanced MRI of Atherosclerosis with Collagen Targeted CNA35-Micelles Mariska de Smet1, Glenda S. van Bochove1, Honorius Sanders1, Francesca Arena2, Willem J. Mulder3, Rob Krams4, Maarten Merkx1, Gustav J. Strijkers1, Klaas Nicolay1 1Eindhoven University of Technology, Eindhoven, Netherlands; 2University of Turin, Turin, Italy; 3Mount Sinai School of Medicine, New York, New York, USA; 4Imperial College London, London, UK

Collagen plays an important role in the stabilization of atherosclerotic plaques. In this study, an MRI contrast agent based on paramagnetic micelles conjugated with collagen binding CNA35 protein, was characterized and tested in a mouse model of stable and vulnerable plaque. Because of their size, high relaxivity, stability in bloodserum and strong binding to collagen, these micelles can be suitable as MRI contrast agent for collagen imaging, for example in atherosclerotic plaques. Initial use of the contrast agent in the mouse model indeed showed that the region where stable (collagen-rich) plaques are expected showed the strongest contrast enhancement.

13:54 516. In Vivo Molecular MRI Using an Elastin-Binding Contrast Agent Investigating Carotid Artery Injury in Mice Marcus Richard Makowski1, Ulrike Sausbier2, Yi Liu Liao2, Markus Schwaiger1, Winfried Neuhuber2, Peter Ruth2, Matthias Sausbier2, Rene M. Botnar1 1Technical University, Munich, Germany; 2Pharmacology, Tuebingen, Germany

Smooth-muscle-cell-proliferation and extracellular-matrix-turnover are thought to play an important role in vessel wall repair after vascular injury. Recently, we identified the cysteine-rich-protein-2 (CRP2) as novel molecular effector in vessel wall repair. We demonstrate the successful use of molecular MRI for the non-invasive assessment of alterations in the vessel wall after vascular injury in a mouse model of impaired smooth-muscle-cell-proliferation and ECM-formation (CRP2-/-). The differentiation of molecular alterations in the injured and non-injured vessel wall, as well as between wild type and CRP2-/- mice with regard to elastin formation after vascular injury could be made using CP1052.

14:06 517. MRI of Coronary Vessel Wall Injury in a Swine Model of Coronary Intervention Using an Eletrostatically Stabilized VSOP Nanoparticle Christian von Bary1, Anne Preissel1, Susanne Wagner2, Marcus Richard Makowski1, Sylvia Schachoff1, Alexandra Keithahn1, Elmar Spuentrup3, Albert Schoemig1, Simon Robinson4, Joel Lazewatsky4, Markus Schwaiger1, Matthias Taupitz2, Rene Michael Botnar, 15 1Klinikum rechts der Isar, Munich, Germany; 2Charité, Berlin, Germany; 3University Hospital Cologne, Cologne, Germany; 4Bristol-Myers Squibb, North Billerica, USA; 5King's College London, London, UK

Abstract Summary We demonstrate the combined use of a matrix specific Gd-based contrast agent (BMS753951) together with an iron oxide nanoparticle for exclusive visualization of the pathologically altered coronary vessel wall.

14:18 518. Novel Nanomedicine for Anti-Inflammatory Therapy of Atherosclerosis Monitored by Multimodality Imaging Mark E. Lobatto1, Stephane Silvera1, Esad Vucic1, Venkatesh Mani1, Manuela Banciu2, Raymond M. Schiffelers2, Klaas Nicolay3, Gert Storm2, John T. Fallon1, James H. Rudd1, Valentin Fuster1, Edward A. Fisher4, Zahi A. Fayad1, Willem J. M. Mulder1 1Mount Sinai School of Medicine, New York, USA; 2Utrecht University, Utrecht, Netherlands; 3Eindhoven University of Technology, Eindhoven, Netherlands; 4New York University School of Medicine, New York, USA

We developed a novel theranostic targeted nanomedicine for the treatment of inflammation related to atherosclerosis. This agent was applied to atherosclerotic rabbits and we used clinical MRI to visualize their delivery and clinical FDG-PET/CT to quantify therapeutic efficacy. In addition, extensive immunohistochemistry and fluorescence microscopy was performed to confirm the in vivo findings.

14:30 519. Detection of Atherosclerotic Plaque Progression: Correlation of Contrast MRI with PET Using 64Cu-Labeled Natriuretic Peptide Kyle S. McCommis1, Raffaella Rossin1, Dana R. Abenschein1, Beth Ochoa1, Geoff E. Woodard2, Michael J. Welch1, Pamela K. Woodard1, Jie Zheng1 1Washington University School of Medicine, St. Louis, Missouri, USA; 2National Institutes of Health, Bethesda, Maryland, USA

In this study, Gadofluorine M enhanced MRI was performed to image the femoral arteries of rabbits with the cholesterol-rich diet and double injury atherosclerotic plaque model. MicroPET imaging with a plaque targeted 64Cu-labeled natriuretic piptide was performed in the same day. Histological and immunohistochemistry images were also gathered. A correlation between enhanced MR signal intensity and SUV of PET images was observed and plaque progression was clearly demonstrated in both images. Further studies are needed to elucidate this correlation.

14:42 520. 3D SPACE MR Imaging of Human Atherosclerotic Femoral Artery at 3.0T Zhuoli Zhang1, Zhaoyang Fan1, YiuCho Chung2, Peter Weale, 2, Timothy J. Carroll1, Ioannis Koktzoglou1, James Carr1, Renate Jerecic2, Mary McGrae McDermott1, Debiao Li1 1Northwestern University, Chicago, Illinois, USA; 2Siemens Medical Solutions, Chicago, Illinois, USA

Magnetic resonance imaging (MRI) could be used for the noninvasive assessment of atherosclerotic plaque burden in the peripheral circulation. Typically 2D dark blood turbo spin-echo (TSE) techniques are used for femoral arterial wall imaging. However, 2D techniques require prolonged imaging time to cover a large region of interest in the leg. Recently, variable-flip-angle 3D TSE T2-weighted (SPACE) has been introduced as a dark blood technique for fast imaging of vessel wall at 1.5T. The purpose of our study was to evaluate the potential of this technique for assessing atherosclerotic disease of the superficial femoral artery (SFA) at 3.0T.

14:54 521. Correlation of 3T-MRI Carotid Artery Wall Volume and B-Mode Ultrasound Intima-Media Thickness Measurements Raphael Duivenvoorden1, Eric de Groot1, John J.P. Kastelein1, J S. Lameris1, Aart J. Nederveen1 1Academic Medical Center, Amsterdam, New Hampshire, Netherlands

Cardiovascular MRI is a promising modality for the assessment of the atherosclerotic disease process. We compared 3T-MRI Arterial Wall Volume measurements with the widly used ultrasound Intima-Media Thickness measurements.

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15:06 522. Spatial Heterogeneity of Carotid Artery Wall Strain Using Displacement-Encoded MRI at 1.5T and 3.0T Alexander Peter Lin1, 2, Lauren Wisk3, Eric Bennett2, Scott Fraser1, Han Wen2 1California Institute of Technology, Pasadena, California , USA; 2National Institutes of Health, Bethesda, Maryland, USA; 3University of California Los Angeles, Los Angeles, California , USA

The spatial distribution of carotid artery wall strain during systolic lumen expansion was measured with displacement-encoded MRI (DENSE). The results reveal spatial heterogeneity of the distribution of distension around the circumference of the artery in healthy volunteers. These results should motivate further investigation of a baseline pattern of the strain distribution in healthy humans and changes associated with vessel disease.

15:18 523. Flow-Sensitive 4D MRI for the Analysis of Aortic Hemodynamics and Wall Shear Stress: Results Form Healthy Volunteers and Follow-Up in Aortic Stenosis Alex Frydrychowicz1, Maximilian F. Russe1, Aurélien F. Stalder1, Alexander Berger1, Andreas Harloff1, Raoul Arnold1, Mathias Langer1, Jürgen Hennig1, Michael Markl1 1University Hospital Freiburg, Freiburg, Germany

In light of the arterial remodeling attributed to factors such as the wall shear stress (WSS) and the oscillatory shear index (OSI) it was the aim of this study to exploit MR’s capability to directly measure blood flow and the option to calculate derived vessel wall parameters. Results in 11 young healthy volunteers were compared with findings in a 13 year-old boy with severe aortic coarctation before, and 5 and 9 month after therapy. Our data suggest that 4D MRI is capable of the detailed analysis of qualitative hemodynamics and derived vessel wall parameters, to show alterations even in areas not directly affected by a pathology, and that 4D MRI is suitable for follow-up examinations.

Manganese in the Brain: Methods to Applications Room 713 A/B 13:30-15:30 Chairs: Ichio Aoki and Afonso C. Silva

13:30 524. Seasonal Plasticity of the Olfactory Circuit in Songbirds Assessed with in-Vivo Manganese Enhanced (MEMRI) Geert De Groof1, Silke Steiger2, Helga Gwinner2, Annemie Van der Linden1 1University of Antwerp, Antwerp, Belgium; 2Max Planck Institute for Ornithology, Seewiesen, Germany

It is generally believed that birds lack a well-developed sense of smell. Yet there is evidence that some songbirds are able to detect odors. Moreover, it has been shown that starlings show seasonal differences in their ability to respond to odor cues, corresponding to their annual breeding pattern. In starlings, odor sensitivity peaks during nest-building in the spring. This study uses repeated in vivo MEMRI to quantify seasonal changes in the anatomy and activity of the olfactory bulb in starling brains. Seasonal plasticity in the avian brain has already been shown with respect to song nuclei.

13:42 525. Functional Mapping of the Auditory Pathway in Adult Mice by Manganese-Enhanced MRI Takashi Watanabe1, Jens Frahm1, Thomas Michaelis1 1Max Planck Institute for Biophysical Chemistry, Goettingen, Germany

This work demonstrates for the first time manganese-enhanced MRI (3D FLASH, 117 µm isotropic resolution) of the lateral lemniscus and the superior olivary complex in adult mice in vivo. These auditory centers in the brainstem presented with pronounced signal enhancements after systemic administration of manganese chloride when animals were exposed to acoustic stimuli for 48 hours, but not when kept in a quiet chamber. The results suggest an activation-dependent accumulation of manganese in the neural circuit connecting the cochlear nucleus via the superior olivary complex and the lateral lemniscus to the inferior colliculus.

13:54 526. In Vivo Tracing Anatomical Circuitry of the Brains Using Gadolinium Carolyn Wan-hsun Wu1, Rebecca Ebitz, Haitao Wu2, Gary Griffiths2, Roger Tootell, Alan P. Koretsky1, Leslei G. Ungerleider 1NIH, Bethesda, Maryland, USA; 2NIH, Rockville, Maryland, USA

A shortcoming of conventional neuroanaomy approaches to study neuronal circuitry is that it requires visualizing transported tracer in the post-mortem, histologically processed tissue. The goal of the study is to expand the MRI contrast media available for in vivo neuronal track tracing. In the present study, we show that Gd-DOTA can be used as a MRI visible track tracing agent that reveals anatomical connections in the monosynaptic, anterograde fashion, with results comparable to conventional anatomical tracer. This finding expands the usefulness of Gd-DOTA for longitudinally anatomical studies, especially to study brain wiring during different developmental stages and rewiring following injuries.

14:06 527. Use of Short Chain Oligo-Glycerolipids to Improve BBB Permeability: Application to Managanese-Enhanced MRI (MEMRI) Alessandro Gozzi1, Adam Schwarz1, Valerio Crestan1, Livia Ferrari1, Peter Hoffmann2, Matthew Roe3, Angelo Bifone1 1GlaxosmithKline Medicine Research Centre, Verona, Italy; 2Genzyme Pharmaceuticals, Cambridge, USA; 3Genzyme Pharmaceuticals, Haverhill, UK

MEMRI methods can be applied to elucidate neuroanatomical information and to identify regions of increased synaptic activity. However the successful application of MEMRI is often limited by the poor permeability of the BBB to Mn2+ ions. Here we investigated whether administration of short chain oligoglycerolipids can enhance the BBB permeability to Mn2+. Our results show robust and homogeneous bi-hemispheric MEMRI signal enhancements following co-administration of oligo-glycerolipids and MnCl2 through carotid artery. These findings corroborate the exploitation of oligo-glycerolipids as a means to achieve high parenchymal concentration of Mn2+ in the brain.

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14:18 528. Overexpression of SOD-2 Reduces Aβ Levels and Improves the Axonal Transport Deficits in the Tg2576 Alzheimer Model Mice Cynthia A. Massaad1, Brandon J. Breitling1, Eric Klann2, Robia G. Pautler1 1Baylor College of Medicine, Houston, Texas, USA; 2New York University, New York, New York, USA

In the present study, we show that overexpression of the mitochondrial superoxide dismutase in the Tg2576 alzheimer mouse model, prior to the onset of oxidative stress, reduces the levels of soluble and insoluble Aβ 1-40 and Aβ 1-42 and improves the axonal transport deficits characteristic of the Tg2576 mice. These studies, combined with previous findings from our lab, support the notion that mitochondrial reactive oxygen species are upstream of Aβ pathology in the course of Alzheimer’s disease.

14:30 529. Longitudinal Studies of Neonatal Cerebellum Phenotypes Development in Gbx2-CKO Mutant Mice Using MEMRI Kamila Urszula Szulc1, 2, Brian J. Nieman1, Roy V. Sillitoe2, Y Z. Wadghiri1, A L. Joyner2, D H. Turnbull1 1NYU School of Medicine, New York, New York, USA; 2Sloan-Kettering Institute, New York, New York, USA

The cerebellum is a critical brain structure involved in coordination and movement control, and there is growing evidence for additional roles in sensory processing. We previously showed that in vivo manganese-enhanced MRI (MEMRI) can be used to detect midline cerebellum defects in Gbx2 conditional knockout (Gbx2-CKO) mice at postnatal day P11 [2]. Gbx2-CKO mice have variable deletion of vermis, the central cerebellum, which motivates the need for longitudinal imaging to understand the temporal evolution of the mutant phenotypes. We therefore performed longitudinal MEMERI studies of Gbx2-CKO mutant and wild type littermates between P3 and P11, performing volumetric analyses of the cerebellum phenotypes in these mice.

14:42 530. Excitotoxic and Physiological Stimulations Provide Similar Signal Enhancement on Manganese-Enhanced MRI Oliviero Gobbo1, 2, Hirac Gurden1, 3, Marc Dhenain1 1CEA, DSV, I2BM, Orsay, France; 2Trinity College, Dublin, Ireland; 3CNRS, Orsay, France

Manganese-Enhanced Magnetic Resonance Imaging (MEMRI) is used to monitor manganese influx into neurons in reaction to functional, physiological, activations. It might thus be used to study functional alterations in animal models of neurodegenerative diseases. However, to date, it is not clear whether excitotoxic events can also modify the MEMRI signal. Here, we showed that, in the olfactory bulb of rats, excitotoxic lesions and odor-evoked physiological activation produce similar MEMRI signal changes. MEMRI studies should thus be conducted with caution in models of neurodegenerative diseases because reduced MEMRI effects caused by functional alterations can be compensated by excitotoxic-related MEMRI enhancement.

14:54 531. Temporal Changes in the T1 and T2 Relaxation Rates (δR1 and δR2) in the Rat Brain Are Consistent with the Tissue-Clearance Rates of Elemental Manganese Kai-Hsiang Chuang1, Alan P. Koretsky1, Christopher H. Sotak 1NINDS, NIH, Bethesda, Maryland, USA

Temporal changes in the T1 and T2 relaxation rates in rat olfactory bulb and cortex before and after i.v. infusion of MnCl2 were compared with the absolute Mn concentrations from the corresponding excised tissue samples. Only a small fraction of the total Mn remained in the brain after 28-35 days. Consequently, the temporal changes in T1 and T2 are mainly due to Mn transport in and out of brain and thus the Manganese-Enhanced MRI signal intensity largely reflects the underlying tissue Mn concentration. This suggests that efflux of cerebral Mn is faster than that reported in earlier studies using other methods.

15:06 532. Detection of Transient Changes in Photothrombotic Cortical Injury by Manganese-Enhanced Magnetic Resonance Imaging Kevin C. Chan1, 2, Huan-xing Su1, Ke Xia Cai1, Chi-tat Chiu1, Matthew M. Cheung1, Wu-tian Wu1, Ed Xuekui Wu1 1The University of Hong Kong, Pokfulam, Hong Kong

This study aims to employ in vivo manganese-enhanced MRI to detect transient changes in adult rat model of photothrombotic cortical injury in different brain regions. Results showed a close pattern of MEMRI signal hyperintensity throughout different brain regions in comparison to the distribution of MnSOD and GS immunoreactivities along the time course, whereby conventional MRI could hardly detect such. It is suggested that exogenous Mn2+ injection may provide enhanced MEMRI detection of oxidative stress and gliosis early in the rat model of photothrombotic cortical injury.

15:18 533. Association Between Reduction in Cerebral Blood Flow and Axonal Transport Deficits in Mouse Models of Diabetes Using MRI Faridis Serrano1, Tomoya Terashima1, Samir Kamalesh Amin, Lingyun Hu1, Lawrence Chan1, Robia Pautler1 1Baylor College of Medicine, Houston, Texas, USA

A prominent characteristic of the metabolic disease, diabetes mellitus, is hyperglycemia. Hyperglycemia is associated with several complications including vascular disease that most likely contribute to diabetic neuropathy. The aim of this study is to examine the association between alterations in cerebral blood flow (CBF) and axonal transport. We observed that hyperglycemia causes deficits in CBF (assessed with arterial spin labeling) as well as decreases in axonal transport (assessed with Manganese-Enhanced MRI). The possibility to evaluate the impact of hyperglycemia on vascular dysfunction and neuronal physiology in vivo using MRI may be useful in understanding the mechanism of hyperglycemia induced neuropathy.

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SPECIAL SYMPOSIUM Ethics in Imaging Research Room 715 A/B 13:30 - 15:30 Chairs: Claudia Hillenbrand and Lawrence L. Wald

Educational Objectives: Upon completion of this course, participants should be able to:

• Identify and resolve shortcomings in ethical treatment of volunteers; • Recognize the critical elements of grants compliance needed to comply with funding agency regulations; and • Apply only proper acquisition and manipulation of scientific digital images.

13:30 Ethics of Incidental Findings – What do you Owe your Subject? A. Gregory Sorensen 14:00 Discussion 14:10 Grants and Contracts – The Gorwing Burden of Regulatory Compliance

Mark Barnes

14:40 Discussion

14:50 Good Scientific Conduct – Ethics in Imaging Research Douglas W. Cromey

15:20 Discussion

Image Markers for Evaluation of Bone & Spine

Room 717 A/B 13:30-15:30 Chairs: John C. Waterton and Felix W. Wehrli

13:30 534. Multi-Center MRI Reproducibility of Cancellous Bone Microstructure at the Distal Radius Bryon R. Gomberg1, Pamela Seaman1, Michael Kleerekoper1 1MicroMRI Inc., Philadelphia, Pennsylvania, USA

Metabolic bone diseases cause small changes to bone quality over long times. Combined with the difficulty in finding naïve patients, the large numbers of patients needed for clinical investigations requires multi-center recruitment and data collection. This study evaluates the multi-center reproducibility and accuracy of commercial technology we have developed for microscopic bone imaging. We found that the multicenter data is as reproducible as previously reported from single centers, and the accuracy across centers falls within the measurement error. This information allows researchers to use the existing validation data to establish sample size estimates for future large studies.

13:42 535. Geodesic Topological Analysis of Trabecular Bone Micro-Architecture of High-Spatial Resolution Magnetic Resonance Images Julio Carballido-Gamio1, Markus B. Huber1, Roland Krug1, Felix Eckstein2, 3, Sharmila Majumdar1, Thomas M. Link1 1University of California, San Francisco, San Francisco, California , USA; 2Ludwig-Maximilians-Universität, Munich, Germany; 3Paracelsus Medical Private University, Salzburg, Austria

In this work Geodesic Topological Analysis or GTA is presented as a new trabecular bone analysis quantification technique. New apparent trabecular bone parameters derived from GTA are also presented: apparent trabecular bone volume distribution (app.Tb.V.D.), apparent trabecular bone junction space (app.Tb.J.Sp.), and apparent trabecular bone distance to junction (app.Tb.D.J). The performance of the proposed methodology is evaluated in terms of its ability in discriminating vertebral fractures based on high-spatial resolution MR images of the calcaneus of 30 specimens. Area under the curve values of the receiver-operator curve analysis showed moderate accuracy demonstrating the potential of the new technique.

13:54 536. Quantification of Bone Water in the Human Tibia in Vivo by Ultra-Short TE Radial MRI at 3T Aranee Techawiboonwong1, Hee Kwon Song2, Catherine E. Jones2, Mary B. Leonard3, Felix W. Wehrli2 1University of Pennsylvania School of Medicine , Philadelphia, USA; 2University of Pennsylvania School of Medicine, Philadelphia, USA; 3Children's Hospital of Philadelphia, Philadelphia, USA

Most of bone water (BW) resides in the microscopic pores of the lacuno-canalicular system. These short-T2 water protons can be quantified by MRI using ultra-short echo-time (UTE) imaging techniques therefore providing an indirect measurement of cortical bone porosity which is known to affect bone strength. Here we developed and evaluated a method based on UTE MRI to quantify BW content as a new metric of bone quality in human cortical bone in vivo. A pilot study in three groups of women showed BW to be a more sensitive discriminator than clinical bone mineral density.

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14:06 537. Vertebra Bone Mineral Density Reduction is Associated with Vertebra Blood Perfusion Reduction: Dynamic Contrast Enhanced MRI Study in a Rat Orchiectomy Model Yi Xiang Wang1, H Zhou, 12, Y F. Zhang3, T Kwok3, D K. Yeung3, L Qin3, G E. Antonio3, J F. Griffith3 1The Chinese University of Hong Kong, Prince of Wales Hospital , Shatin, People's Republic of China; 2First Affiliated Hospital of Zhejiang University, Hangzhou, People's Republic of China; 3The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, People's Republic of China

Recent clinical studies have shown that both in male and female human subjects vertebral marrow blood perfusion is significantly decreased in the osteoporotic subjects as demonstrated by MRI derived blood perfusion parameters. In a group of matured male rats, the current study demonstrated that vertebra bone mineral density decreased by 16.6% and MRI maximum enhancement decreased by 17% at 4 weeks post- bilateral orchiectomy. The results showed it is feasible to reproduce the clinical observations that a decease of vertebra bone mineral density is associated with a decease of vertebra blood perfusion in this male rat osteoporosis model.

14:18 538. Quantitative Water and Fat Suppressed Proton Projection MRI (WASPI) Measurement of Bone Matrix Density Differentiates Normal, Osteoporotic and Osteomalacic Bone Haihui Cao1, 2, Jerome L. Ackerman, 23, Ara Nazarian, 24, Brian D. Snyder, 24, Guangping Dai, 23, Melvin Glimcher1, 2, Yaotang Wu1, 2 1Children's Hospital, Boston, Massachusetts, USA; 2Harvard Medical School, Boston, Massachusetts, USA; 3Massachusetts General Hospital, Boston, Massachusetts, USA; 4Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA

Bone matrix density is important for evaluating the degree of bone mineralization in the study and diagnosis of metabolic bone diseases. Quantitative water and fat suppressed proton projection MRI (WASPI) was utilized to measure bone matrix densities of normal, osteoporotic, and osteomalacic rat bone specimens. Osteoporotic trabecular bone matrix density was much lower than in the normal and osteomalacic states, while cortical bone matrix density was not significantly altered. This method offers the potential, for the first time, of a noninvasive clinical means to differentiate osteoporosis from osteomalacia.

14:30 539. Manganese-Enhanced Magnetic Resonance Microscopy of Mineralization Rates Ingrid E. Chesnick1, Jose A. Centeno2, Todor I. Todorov3, Alan E. Koenig3, Kimberlee Potter1 1Armed Forces Institute of Pathology Annex, Rockville, Maryland, USA; 2Armed Forces Institute of Pathology, Washington, District Of Columbia, USA; 3USA Geological Survey, Denver, Colorado , USA

Manganese can be employed to sensitize the Magnetic Resonance Microscopy (MRM) technique to the deposition of bone in mineralizing tissues. In this work, manganese-enhanced MRM was used to establish that the mineralizing activity of organ-cultured calvariae is much higher after 1 day in culture compared to 22 days in culture. It was also discovered that different regions of the embryonic skull mineralize at different rates. These results support the application of Mn-enhanced MRM to the study of different treatment paradigms on mineralization rates.

14:42 540. Bone Susceptibility Quantification: In Vivo Feasibility with MR Source QUantification by Inverting the Dipole Field Ludovic de Rochefort1, Ryan Brown1, Martin R. Prince1, Yi Wang1 1Weill Medical College of Cornell University, New York, New York, USA

Bone mineral density is an important parameter for evaluating osteoporosis and other bone diseases. To avoid invasive biopsy and exposure to ionizing radiation, there have been several works using MRI to quantify bone density. One approach makes use of the susceptibility difference between the various constituents of bone tissue, which is linked to its composition. Here we show the in vivo feasibility of MR-SQUID (Magnetic Resonance Source QUantification by Inverting the Dipole field) to measure bone magnetic susceptibility by fitting the observed field shifts to a field model built from segmented signal intensity images.

14:54 541. MR Diffusion Measurements Are Sensitive in Detecting the Effect of Age and Loading on the Response of Intervertebral Discs Ron N. Alkalay1, Carl-Fredrik Westin2 1Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA; 2Brigham and Women's Hospital, Boston, Massachusetts, USA

The aim of this MR study was to contrast the ability of diffusion and T2 weighted protocols to detect the affect of age and mechanical loading on the disc’s anatomy. L2-L3 discs, obtained from human donors aged 39 and 72 yrs. underwent T2Map and Diffusion MR measurement protocols in an unloaded state and once exposed to 800N compressive load. Both methods were able to delineate the anatomy of the tissue and the loss in definition due to age. Under applied compression, diffusion measures demonstrated increased sensitivity in detecting the differences in the mechanical response of the disc, independent of age.

15:06 542. New MRI Methods for the Monitoring of the Intervertebral Disc Ablation Galit Saar1, Yoram Zilberman2, Hadassah Shinar1, Gadi Pelled2, Dan Gazit2, Gil Navon1 1Tel Aviv University, Tel Aviv, Israel; 2Hebrew University - Hadassah Medical Campus, Jerusalem, Israel

MRI contrasts such as T2, MTR, dipolar echo refocusing, as well as 2H double quantum filter were used to monitor early changes occurring after nucleus pulpous ablation of IVD. In the ablated disc the clear distinction between nucleus and annulus is lost, T2 is significantly shorter and 1/Tdipol, a measure of the contribution of the dipolar interaction to the transverse relaxivity, as well as MTR, are larger. These results indicate the spread of the collagen fibers into the inner part of the ablated disc providing a baseline for future work on disc degeneration and repair.

15:18 543. MR Spectroscopy in Intact and Degenerated Bovine Intervertebral Disc Jin Zuo1, Ehsan Saadat2, Xiaojuan Li1, Sharmila Majumdar1 1Univ. of California, San Francisco, San Francisco, California , USA; 2Univ. of California, San Francisco, San Francisco, California , USA

Intervertebral Disc Disease (IVDD) is a leading cause of lumbar spine-related lower-back pain. A new technique using single voxel MR spectroscopy was developed for the quantification of the concentration of metabolites in the intervertebral disc to detect disc degeneration. The study tested the feasibility of the method in bovine intervertebral discs and examined the changes in concentration of metabolites as a result of papain-induced degeneration of bovine discs in vitro.

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HANDS-ON WORKSHOP 2 Body and Cardiovascular Protocol Optimization Philips Medical Systems Room 709 13:30 – 15:30

Siemens Medical Solutions Room 711 13:30 – 15:30

fMRI Applications: Non-Clinical Room 801 A/B 16:00-18:00 Chairs: Vanessa A. Sluming and Thomas M. Talavage

16:00 544. Brain-Computer-Interface Using Real-Time FMRI: Thought-Controlled Robot Arm Jong-Hwan Lee1, Jeongwon Ryu2, Ferenc A. Jolesz1, Zang -Hee Cho2, Seung-Schik Yoo1 1Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA; 2Gachon Medical School, Incheon, Republic of Korea

We presented the feasibility of voluntary control of robotic arm using the thought process (regulation of the somatomotor activation via motor imagery) using real-time fMRI. Although the robotic arm was used as the means to link the thought process to the explicit tangible motion, translation into computer control commands, such as continuous cursor movement (i.e. replacing computer mouse) is also possible.

16:12 545. Parallel Real-Time FMRI with Two Connected High-Field Scanners (3T, 7T) Tobias Moench1, Maurice Hollmann1, Ramona Grzeschik1, Michael Luchtmann1, Ralf Luetzkendorf1, Sebastian Baecke1, Johannes Bernarding1 1University of Magdeburg, Magdeburg, Germany

We enhanced a custom-made real-time fMRI software system to support the parallel usage of two or more high-field MRI scanners based on an XML-based experiment description language. We realized first experiments involving interactions between each two volunteers being measured in 3T and 7T MRI scanners in parallel. Each volunteer received feedback of his and of the opponents' current activation level. We also introduced dynamic financial rewards. Depending on the actual BOLD response of each single run (24secs) the final reward could be increased. The current financial state was continuously displayed with the activation scores to increase the volunteers' motivation.

16:24 546. Effect of Pulsed Magnetic Field on FMRI Processing of Pain John A. Robertson1, 2, Jean Theberge1, 3, Julie Weller2, Dick J. Drost1, 3, Frank S. Prato1, 3, Alex W. Thomas1, 2 1Lawson Health Research Institute, London, Canada; 2University of Western Ontario, London, Canada; 3St. Joseph's Health Care, London, Canada

The effect of a specific pulsed magnetic field on pain processing was investigated using fMRI. Normal subjects were given acute thermal pain while imaged. Then, a pulsed magnetic field exposure (or sham condition) was given using a custom gradient program, and the functional imaging of pain repeated. The data was analyzed using Brain Voyager, and differences were found between groups in the cingulate cortex. These results demonstrate the effect of pulsed magnetic fields on neural processing.

16:36 547. Dexterity and Implicit Learning of Sequential Movements Maite Aznárez-Sanado1, María A. Fernández-Seara1, Francis Loayza1, Maria A. Pastor1 1Center for Applied Medical Research, University of Navarra, Pamplona, Spain

The present study was designed to identify the dynamic activation changes within the basal ganglia and related motor regions during the initial learning of sequential finger movementsDexterity influences the effect of sequential movements repetition. When performing repetitive sequential movements with the right hand compared with the left hand and bimanually the recruitment of posterior parietal and premotor areas including left DLPC was greater. Cerebellar somatosensory cortex activation was also directly related with repetition.The areas attenuated with sequence repetition involved mainly the spatial attentional network needed for a visuospatial learning task, with subsequent movement sequence performance.

16:48 548. Neural Activity in Human Auditory and Sensorimotor Cortices Modulated by Passively Varied Divided Attention – an FMRI Study Maolin Qiu1, J Arora1, Jitendra Bhawnani1, N Rajeevan1, Scott McIntyre1, Terrence W. Nixon1, R T. Constable1 1Yale University School of Medicine, New Haven, Connecticut, USA

There is much interest in human fMRI studies in understanding the impact of baseline brain activity on the activation observed. To study this, baseline is often altered with an anesthetic agent which leads to additional confounds such as pure vascular effects and attention effects that must be accounted for in order to examine the direct impact on neuronal activity. Using auditory and tactile stimulation alone and simultaneously we demonstrate that the simultaneous multi-sensory stimulation does alter the primary sensory activation indicating the equivalent of a passive attention manipulation.

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17:00 549. High Resolution Functional MRI Imaging of Material-Specific Encoding in the Head, Body and Tail of the Hippocampus Wendy Ringe1, Kaundinya Gopinath1, Sergey Cheshkov1, Subhendra Sarkar1, Richard Briggs1, Robert Haley1 1UT Southwestern Medical Center, Dallas, Texas, USA

Limited field of view, high resolution fMRI is used to demonstrated hippocampal hemisphere- and region-specific activity during a memory paradigm. Activation related to material-specific encoding is differentiated from basic material-specific visual processing for four stimuli types in the hippocampal head, body and tail: Words - bilateral (left greater than right) head, left body and tail; Nameable Objects - bilateral (right greater than left) head, left body, and right tail; Faces - bilateral head and tail; Nature Scenes left head, bilateral body and tail. High-resolution limited-coverage acquisitions is useful to study parcellation of memory processes within the hippocampus.

17:12 550. ASL Perfusion FMRI to Image Psychomotor Vigilance Time-On-Task Effects in the Human Brain Hengyi Rao1, 2, Julian Lim1, Wenchau Wu1, Jiongjiong Wang1, John A. Detre1, David F. Dinges1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA

ASL perfusion fMRI was used to examine the neural correlates of performance decline and mental fatigue induced by a continuous 20-minute psychomotor vigilance test (PVT). Elevated subjective report of fatigue scores were associated with global CBF changes from the beginning to the end of the task, while prolonged reaction times were associated with regional CBF changes in the thalamus-parietal-cingulate-frontal network both during task and baseline periods. These findings demonstrate the feasibility and utility of ASL perfusion fMRI for imaging time-on-task effects, and provide a neural basis for the dissociation between subjective mental fatigue and objective performance stability.

17:24 551. Using FMRI to Explore Secondary Somatosensory Areas in the Lateral Sulcus of Squirrel Monkeys Na Zhang1, Limin Chen1, Gregory H. Turner1, R. Friedman2, A. W. Roe2, John C. Gore1, Malcolm J. Avison1 1Vanderbilt University Institute of Imaging Science, Nashville, Tennessee, USA; 2Vanderbilt University, Nashville, Tennessee, USA

While primary somatosensory cortex (SI) in non-human primates has been extensively mapped using electrophysiology (Kaas), optical imaging of intrinsic signal (OIS; Chen), and fMRI (Chen), less is known about the fine scale topographic organization of secondary somatosensory cortex (SII), due in large part to its inaccessibility for optical imaging. We previously demonstrated that somatotopic maps collected using high field BOLD fMRI are in close agreement with those obtained in the same animal using OIS and electrophysiology. We further demonstrated the ability of high field BOLD fMRI to resolve submillimeter shifts in cortical activation that are the neural correlates of the sensory funneling illusion in SI. We have now used the same BOLD fMRI methods to examine the fine somatotopic organization of digits in SII of squirrel monkey, and to determine whether similar cortical correlates of sensory funneling are present in SII. Our results revealed that each digit activated distinct somatotopically organized anterior and posterior areas of SII. This organization in SII was consistently reproducible within and across animals. These studies demonstrate the ability of high field BOLD fMRI to map the functional organization of the non-human primate brain at submillimeter resolution in areas that are inaccessible to optical imaging techniques, and require the sacrifice of the animal for electrophysiological mapping studies. Furthermore, they represent some of the first data suggesting that sensory funneling may have neural correlates beyond SI.

17:36 552. Linking Genes to Brain Function: Expression of Serotonin 5-HT1A Receptors in Specific Neuronal Populations Results in Divergent PhMRI Responses to the Selective Agonist 8-OH-DPAT Alessandro Gozzi1, Adam Schwarz1, Valerio Crestan1, Theodoros Tsetsenis2, Enrica Audero2, Luisa Lo Iacono2, Cornelius thilo Gross2, Angelo Bifone1 1GlaxosmithKline Medicine Research Centre, Verona, Italy; 2EMBL, Monterotondo, Italy

Transgenic mouse lines selectively expressing the serotonin 5-HT1A receptor in specific brain regions have been recently developed to investigate the role of discrete forebrain circuits in anxiety and depressive disorders. Here we have applied phMRI to characterize brain functionality in wild-type, serotonin 5-HT1A knockout mice (KO), and in transgenic lines selectively expressing the receptor in the central amygdala. Results highlighted divergent functional roles of distinct receptor populations belonging to the same neurotransmitter system. This study demonstrates the potential of phMRI as a tool to phenotype genetically engineered animals and to explore the correlation between genes and brain function in vivo.

17:48 553. Behavioral Correlates of Negative BOLD Signal Changes in the Primary Somatosensory Cortex Juergen Baudewig1, Andreas Kastrup1, Sonja Schnaudigel1, Lars Becker1, Jan Martin Sohns1, Peter Dechent1 1Georg-August-University Goettingen, Goettingen, Germany

Aside from positive BOLD signals there is converging evidence that neuronal responses also induce negative signals. Although it is believed that these negative BOLD signals reflect suppression of neuronal activity direct evidence for this assumption is lacking. The aim of this study was to determine the functional significance of negative BOLD responses during unilateral electrical median nerve stimulation. Positive BOLD changes were observed in the contralateral, whereas negative BOLD changes could be detected in the ipsilateral primary somatosensory cortex. Additional psychophysiological experiments revealed that these focal cortical fMRI signal decreases reflect a functionally effective inhibition in the somatosensory system.

Segmentation & Localization Room 718 A 16:00-18:00 Chairs: Qi Duan and Ron Kikinis

16:00 554. Novel Statistical Models and Segmentation Methods for Fiber Bundles in DTI Suyash Prakash Awate1, Hui Zhang1, James C. Gee1 1University of Pennsylvania, Philadelphia, USA

We present novel methods for statistically modeling and segmenting fiber bundles in diffusion-tensor images.

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16:12 555. Temporal Dynamics 4D Level Set Method for Segmentation of MR Renography Images Ting Song1, Henry Rusinek2, Qun Chen2, Louisa Bokacheva2, Jeff L. Zhang2, Andrew F. Laine1, Vivian S. Lee2 1Columbia University, New York, New York, USA; 2NYU School of Medicine, New York, New York, USA

A novel 4D segmentation framework based on a temporal dynamics 4D level set requires less than one minute to automatically segment a 4D data set with more than 40 time points. The novelty of the method is that it combines both information from spatial anatomical structures and temporal dynamics from the time axis. The performance of the fully automatic 4D level set algorithm was found to be comparable to manual segmentation performed by two experts in renal anatomy.

16:24 556. Brain MR Image Segmentation by Minimizing Scalable Neighborhood Intensity Fitting Energy: A Multiphase Level Set Approach Chunming Li1, Li Wang2, Chiu-Yen Kao3, Zhaohua Ding1, John C. Gore1 1Vanderbilt University, Nashville, Tennessee, USA; 2Nanjing University of Science and Technology, Nanjing, People's Republic of China; 3The Ohio State University, Columbus, Ohio, USA

Intensity inhomogeneity is often seen in MR images, and these cause considerable difficulties in applying existing image segmentation algorithms. In this work, we propose new multiphase level set method for brain MR images segmentation. The proposed method is able to segment images with intensity inhomogeneities, without the bias field correction. Our method has been applied to brain MR images at 3T with promising results.

16:36 557. MRI Measurement of Ischemic Brain Penumbra Using Kohonen’s Multi-Parametric Self-Organizing Map (KMP-SOM) Technique Hassan Bagher-Ebadian1, 2, Kourosh Jafari-Khouzani1, Panayiotis D. Mitsias1, Michael Chopp1, 3, James R. Ewing1, 3 1Henry Ford Hospital, Detroit, Michigan, USA; 2Amir-Kabir University of Technology, Tehran, Iran; 3Oakland University, Rochester, Michigan, USA

Experimental and clinical studies indicate that the likelihood for progression to infarction in the penumbra of physiologically impaired but potentially salvageable tissue surrounding in stroke ischemia is the most important factor in evaluating treatment efficacy. Thus, a multi-parametric analysis that increases the ability of investigators to characterize ischemic penumbra in the early stages of stroke may have a profound clinical significance. In this study, Kohonen’s Multi-Parametric Self Organizing Map (KMP-SOM) technique was used to detect the ischemic penumbra using MR acute information (T1 pre-contrast, T2, Diffusion-Weighted and proton density). Considering the DW and T2 lesions, the KMP-SOM maps have distinguished the penumbra and core of the lesions much better than ISODATA. We conclude that a KMP-SOM is capable of predicting the size and pattern of ischemic penumbra, from MR acute information and such modeling may play an important role in the assessment of subacute therapeutic interventions in the treatment of stroke.

16:48 558. Segmentation of Colorectal Cancer MR Images Niranjan Bhaskar Joshi1, Sarah Bond2, Michael Brady1 1University of Oxford, Oxford, UK; 2Siemens Molecular Imaging, Oxford, UK

Relative distance of tumour from the mesorectal fascia (MF) in colorectal MR images provides important information about the stage of the cancer and likely success of the surgery. We present an image segmentation algorithm to estimate the position of the MF and size and location of the tumour using computer automated methods. Experiments are performed on oblique T2 weighted MRI dataset collected from 10 patients. Results show that the maximum of the average differences between an expert’s delineation of the MF and that segmented with our algorithm is just over 2 mm, which is equivalent to 3-5 pixels.

17:00 559. HippoQuant: Combining Geometrical and Intensity Information for 3D Hippocampus Detection in 3D T1-Weighted MRI Images Boubakeur Belaroussi1, Michael O'Sullivan2, Fabrice Vincent1, Chahin Pachai1 1Bio-Imaging Technologies S.A.S, Lyon, France; 2Neurologische Klinik, Ludwig-Maximilians-Universität, Munchen, Germany

In this work, we proposed HippoQuant, a new, fast, semi-automatic hippocampus segmentation procedure in 3D T1-weighted MRI images based on user-defined landmarks. From a set of user-defined landmarks, a 3D discrete hippocampus surface model is geometrically deformed using an Iterative Closest Point transform, supplemented by a Thin Plate Spline transform. This step leads to a “binary mask”. In parallel, the 3D MR image is segmented into 3 tissue classes (WM, GM and CSF) to identify CSF or CSF-like structures (uncal sulcus and “black holes”) located within the hippocampus. The output is a “presegmentation mask”. In the final step, the binary and presegmentation masks are merged to generate a hippocampal mask. HippoQuant combined both geometrical and statistical information, leading to potentially dramatic reductions in rater time and interaction, greater reliability, and a technique that is insensitive to variations in hippocampal size and shape, - all - important considerations for application in multi-centers studies.

17:12 560. Identification of Intratumour Low Frequency Microvascular Components Via BOLD Signal Fractal Dimension Mapping Graeme Wardlaw1, 2, Raimond Wong1, 3, Pierre Major1, 3, Michael D. Noseworthy1, 2 1McMaster University, Hamilton, Canada; 2Brain-Body Institute, Hamilton, Canada; 3Oncology, Hamilton, Canada

Typical clinical evaluation of tumour microvasculature utilises dynamic contrast enhanced MRI (dceMRI). However, this approach utilises numerous mathematical models with characteristic physiologic assumptions, often leading to inconclusive results. Alternatively, blood oxygen level dependent (BOLD) magnetic resonance imaging (MRI) is sensitive to the microvascular environment through fluctuation in the oxyhemoglobin to deoxyhemoglobin ratio. Consequently, quantification of the BOLD signal's temporal complexity using a fractal dimension index allows maps to be generated that are physiologically distinct and provide insight into tumour microvasculature without prior assumption as in dceMRI. This approach to tumour microvascular evaluation is presented using rectal cancer data.

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17:24 561. An Approach to Prostate Segmentation on MR Images Zhengyi Yang1, Aleksandra Zapotoczna2, Giuseppe Sasso2, John Simpson2, Gary Cowin1, Deming Wang1 1University of Queensland, Brisbane, Australia; 2The Townsville Hospital, Australia

While contouring the prostate manually, oncologists know the pelvic anatomy (not only the shape of prostate, but also its spatial relationship with other organs, such as bladder, rectum, and seminal versicles) and take the intensity distribution not only within but also surrounding the prostate into account. In order to incorporate this a prior knowledge of the neighbouring intensity distribution into model based segmentation method, Intensity Distribution Shell (IDS) model was proposed in this study. Given a prostate surface, by dilating and shrinking given numbers of voxels, we get two new surfaces enclosing the neighbouring tissues. The volume between these two surfaces is called a shell. The number of voxels is the shell thickness. The IDS model is the integration of a shape model obtained by principal component analysis (PCA) and an intensity distribution model represented by the histogram of the voxels within a shell with predefined shell thickness enclosing the shape surface.

17:36 562. Robustness of Morphologic Features for the Characterization of Mass Lesions in Dynamic, Contrast-Enhanced Breast MR Images Thomas Buelow1, Lina Arbash Meinel2, Axel Saalbach3, Rafael Wiemker1, Martin Bergtholdt1 1Philips Research Europe, Hamburg, Germany; 2Philips Research North America, Briarcliff Manor, New York, USA; 3Philips Research Europe, Aachen, Germany

Dynamic contrast enhanced breast MRI has been emerging as diagnostic tool. Due to its limited specificity there is a demand for computer aided diagnosis tools for this application. In order to build robust CAD applications yielding understandable and reproducible results, a carefully selected small set of features should be used. In this paper we compare three morphologic features with respect to their robustness against variations in the mass lesion segmentations that are the input to the feature computation step. The newly proposed feature "Normalized Mean Distance to Surface" proves more robust and more specific wrt. to lesion characterization than the common features "sphericality" and "compactness".

17:48 563. An Automated Assessment of White Matter Lesions Based on Regional FLAIR Intensity Evaluation Jacobus F.A. Jansen1, Paul A.M. Hofman1, Walter H. Backes1 1Maastricht University Hospital, Maastricht, Netherlands

White matter lesions (WML) are areas of bright, high signal intensity in the white matter depicted on T2-weighted magnetic resonance imaging. In a population with relatively mild WML, namely patients with localization-related, cryptogenic epilepsy and healthy volunteers, the performance of an automated WML detection algorithm, based on regional intensity evaluation, was assessed. The WML volumes from the automated segmentation method were found to be significantly correlated to the volumes obtained visually by neuroradiological assessment. The automated WML detection algorithm using a regional Z-score analysis can successfully segment and quantify the WML on FLAIR images.

Diffusion Imaging of Tissue Microstructure Room 718 B 16:00-18:00 Chairs: Christian Beaulieu and Jeffrey J. Neil

16:00 564. Diffusion Tensor Imaging Detects Mossy Fiber Sprouting in Rat Hippocampus After Status Epilepticus Teemu Petteri Laitinen1, Jari Nissinen1, Asla Pitkänen1, Olli H.J. Gröhn1 1University of Kuopio, Kuopio, Finland

The ability of diffusion tensor imaging to detect mossy fiber sprouting in dentate gyrus was studied in two different animal models of epilepsy. Our results show that the volume and fractional anisotropy of dorsal dentate gurys, determined from FA maps, is increased six months after status epilepticus when compared to healthy control animals. Histological evaluation showed significant increase in the density of mossy fiber sprouting during epileptogenesis in the diseased animals, consistent with the DTI results. The results of this study suggest that mossy fiber sprouting can be detected using DTI.

16:12 565. Quantitative Comparison of Fiber Properties from DTI, HARDI and Light Microscopy Ann S. Choe1, 2, Xin Hong1, 2, Daniel C. Colvin1, 2, Iwona Stepniewska2, zhaohua Ding1, 2, Adam W. Anderson1, 2 1Vanderbilt University Institute of Imaging Science, Nashville, Tennessee, USA; 2Vanderbilt University, Nashville, Tennessee, USA

Measurements of fiber orientation and coherence were made using diffusion tensor imaging (DTI), high angular resolution diffusion imaging (HARDI), and light microscopy of myelin stained tissue sections. Quantitative comparisons of these data show the strengths and limitations of diffusion MRI in revealing microscopic fiber structure in the brain.

16:24 566. Direct Correlation Between Diffusion Tensor Imaging and Electron Microscopy of the Fornix in Humans with Temporal Lobe Epilepsy Luis Concha1, Daniel J. Livy1, Donald W. Gross1, B. Matt Wheatley1, Christian Beaulieu1 1University of Alberta, Edmonton, Canada

Biophysical mechanisms of water diffusion anisotropy in nervous tissue have been studied in animal models and post-mortem human brain; however, there are no direct studies of fresh human white matter. Diffusion tensor imaging in-vivo and follow-up electron microscopy of the same white matter tract is required in humans. The fornix (principal output of hippocampus) was excised during surgery for intractable temporal lobe epilepsy and analyzed quantitatively with electron microscopy. White matter micro-structure was correlated with pre-operative diffusion tensor parameters. Higher extra-axonal fraction and lower axonal density were related to reduced diffusion anisotropy and increased perpendicular diffusivity of the fornix.

16:36 567. In-Vivo Measurement of the Axon Diameter Distribution in the Rat’s Corpus Callosum Daniel Barazany1, Peter J. Basser2, Yaniv Assaf1 1Tel Aviv University, Tel Aviv, Israel; 2National Institutes of Health, Bethesda, Maryland, USA

The axon diameter distribution (ADD) is an important anatomical feature of nerve fascicles. In this work, we use AxCaliber- a new diffusion MRI based framework, to extract the ADD within the corpus callosum (CC) of the rat, in vivo. By altering the diffusion time and diffusion weighting we could fit the data to extract the ADD for each image voxel. With this methodology we were able to segment the CC to at least 5 distinct regions each one them characterized by a unique ADD. The ADD of each region corresponded with the known anatomical morphology of the corpus callosum.

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16:48 568. Recognition of Grey Matter and Parallel Versus Crossing Fibre Bundles Within White Matter Using HARDI Data and a Supervised Learning Algorithm Susanne Schnell1, Björn Wolf Kreher1, Jürgen Hennig1, Hans Burkhardt2, Valerij Kiselev1 1University Hospital Freiburg, Freiburg, Germany; 2Albert-Ludwigs University Freiburg, Freiburg, Germany

In the present study, we recall methods from pattern recognition problems aiming at recognition of three different tissue types: grey matter and fibre crossing bundles versus parallel fibre bundles in white matter by using high angular resolution diffusion imaging (HARDI) and T1-weighted MRI. We engage a support vector machine, which has demonstrated a robust performance in a number of applications. HARDI data are represented by rotational invariant weights of low-order spherical harmonics. The method was systematically tested in simulations and successfully applied to an in vivo data set.

17:00 569. Q-Ball Imaging of the Spinal Cord Julien Cohen-Adad1, 2, Maxime Descoteaux3, Rachid Deriche3, Serge Rossignol1, Richard D. Hoge4, Habib Benali2 1GRSNC, Department of Physiology, Faculty of Medicine, Université de Montréal, Montreal, Canada; 2INSERM U678, Université Pierre et Marie Curie (Paris VI), CHU Pitié-Salpêtrière, Paris, France; 3Odyssée Project Team, INRIA/ENPC/ENS, INRIA Sophia Antipolis, France, France; 4Unité de Neuroimagerie Fonctionnelle, CRIUGM, Université de Montréal, Montreal, Canada

We applied q-ball imaging (QBI) in an ex vivo spinal cord to investigate how this technique might recover various fiber crossing in the spinal cord. We compared the added value of QBI over DTI. We showed that QBI can recover crossing fiber information in the ex vivo spinal cord, where the DTI approach is limited. To our knowledge, this is the first QBI study demonstrating the benefits of QBI for observing longitudinal, dorso-ventral and commissural fibers in the spinal cord.

17:12 570. Examining Tumor Microstructure with Temporal Diffusion Spectroscopy Daniel C. Colvin1, Mark D. Does1, Zou Yue1, C Chad Quarles1, John C. Gore1, Thomas E. Yankeelov1 1Vanderbilt University Institute of Imaging Science, Nashville, Tennessee, USA

The increasing use of diffusion MRI, in both research and clinical settings, has emphasized the need for a more quantitative understanding of the pathophysiological factors affecting water diffusion rates on microscopic scales. While currently employed pulsed gradient spin echo (PGSE) methods are sensitive to restrictions of water displacements on the order of several microns (10-6 meters), the ADC of tissues is affected by interactions occurring on much smaller scales. By employing oscillating gradient spin echo (OGSE) techniques, these microscopic dimensions may be probed and variations in tissue microstructure, as may occur in tumors responding to therapy, may be assessed.

17:24 571. Changes in Pinnation Angle and Fiber Length of Muscles Under Plantar- And Dorsi-Flexion and Force Production - In-Vivo, DTI Based Fiber Tractography in Humans Shantanu Sinha1, chandan mishra2, David Shin3, Ryuta Kinugasa4, John Hodgson3, Reggie V. Edgerton3, Usha Sinha5 1UCSD, San Diego, California , USA; 2UCSD, San diego, California , USA; 3UCLA, USA; 4UCSD, USA; 5SDSU, USA

DTI-based Fiber tracking of different muscle groups in the human lower leg was performed in-vivo under conditions of rest, plantar-(PF), dorsi(DF)-flexion and active force production. Pennation angles were shown to increase upon plantarflexion in soleus and Medial Gastronemius(MG), and remains nearly same upon dorsiflexion with respect to the normal rest state. Fiber lengths also decreased both in soleus and MG upon PF and DF These results are in concurrence with previous ultrasound studies.

17:36 572. A Comparison of In Vivo and Ex Vivo Diffusion Tensor Imaging in the Same Patient Jennifer Andrea McNab1, Natalie L. Voets1, G Douaud1, Ned Jenkinson2, Tipu Aziz2, Karla L. Miller1 1University of Oxford, Oxford, UK; 2University of Oxford, UK

A method is presented for high-resolution 3D diffusion tensor imaging (DTI) in whole, human, fixed brain on a clinical scanner. Whereas previous post-mortem studies have focused on animal brains or small sections of human tissue, this study presents the highest resolution, whole human brain DTI yet reported. Using a rare case study that includesin vivo and ex vivo DTI in the same patient, a direct comparison is made between in vivo and ex vivo anisotropy patterns, illustrating the visualisation of additional structure in the high resolution post-mortem images.

17:48 573. Diffusion Tensor Spectroscopy of Myo-Inositol in Human Brain Jacob Ellegood1, Chris C. Hanstock1, Christian Beaulieu1 1University of Alberta, Edmonton, Canada

Diffusion Tensor Spectroscopy (DTS) of myo-inositol (mI) has not been measured previously in human brain, although due to its compartmentalization in glial cells it may have different diffusion properties than N-acetyl aspartate in neurons and axons. Using high b values (~5000 s/mm2) and a two point measurement, the fractional anisotropy value of mI was determined to be elevated in a subcortical white matter region, rather unexpectedly, when compared to an occipital gray matter region in human brain.

Animal Cardiac Imaging Frontiers Room 714 A/B 16:00-18:00 Chairs: Frederick H. Epstein and Brenda Klaunberg

16:00 574. Four-Dimensional MR Microscopy of the Mouse Heart Using Radial Acquisition and Liposomal Gadolinium Contrast Agent Elizabeth Kathleen Bucholz1, Ketan Ghaghada1, Yi Qi1, Srinivasan Mukundan1, G. Allan Johnson1 1Duke University, Durham, North Carolina, USA

We propose a 3D-plus-time radial (4DRA) MRI pulse sequence that allows rapid acquisition of high-resolution cine images at isotropic 87 μ;m resolution through the use of a liposomal Gd contrast agent. High-resolution images allow more sensitive calucation of functional cardiac parameters, e.g. ejection fraction (EF), end-diastolic volume (EDV), end-systolic volume (ESV) and stroke volume (SV), as well as visualization of coronary arteries and all 4 cardiac valves. The study was applied to 10 mice and EDV, ESV, EJ and SV were measured. The high spatial resolution and rapid acquisition time of 31 minutes present the 4DRA as an excellent candidate for high throughput cardiovascular imaging of the mouse.

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16:12 575. Cardiac Magnetic Resonance Imaging Without General Anesthesia in Mice Christopher J. Berry1, Daniel R. Thedens1, Nikhil K. Iyengar1, Jordan D. Miller1, Kathy Zimmerman2, Robert M. Weiss1 1University of Iowa, Iowa City, Iowa, USA; 2VA Medical Center, Iowa City, Iowa, USA

The purpose of this study was to determine whether cardiac MRI (CMR) can be reliably performed using deep sedation with midazolam and morphine and to assess its impact on image quality and cardiac function compared to traditional anesthesia protocols. Six normal mice and four mice with ischemic heart failure underwent two sessions of CMR with each anesthesia regimen. CMR performed under deep sedation yielded comparable image quality and significantly less artifactual depression of heart rate and ejection fraction compared to CMR performed under general anesthesia and is thus advantageous over traditional anesthesia protocols for assessment of cardiovascular function.

16:24 576. A Relaxographic Analysis of Multi-Compartmental Water Exchange in Isolated Perfused Rat Hearts John Georg Seland1, Morten Bruvold1, Sissel Skarra1, Heidi Brurok1, Per Jynge1 1Norwegian University of Science and Technology, Trondheim, Norway

We have determined water exchange rates across membranes in isolated perfused rat hearts together with volume fractions of the intracellular, intravascular and extracellular compartments. The exchange rate across cell- and vascular membranes was found to be equal in values. Intriguingly the water exchange from ic to ec compartments was found to be more restricted using manganese ions, indicating an intracellular spatially localization of this substance.

16:36 577. Combined Functional MRI and μPET Measurements in a Mouse Model of Cardiac Infarction Edwin Heijman1, 2, Lars Stegger3, Michael Schäfers3, Klaas Nicolay2, Gustav J. Strijkers2 1Philips Research, Eindhoven, Netherlands; 2Eindhoven University of Technology, Eindhoven, Netherlands; 3University Hospital of Münster, Münster, Germany

Global mouse cardiac function of a control group (n=12) and infarct group (n=11) were compared with MRI and PET. In addition, for the permanent occlusion model (n=4) and ischemia-reperfusion mouse model (n=4) PET infarct size was determined and compared with contrast-enhanced MRI and CINE MRI infarct size measures. Global functional parameters determined by MRI and PET were in good agreement, while LVM was underestimated by PET. PET infarct size did not correlate with the different MRI infarct size measures, probably caused by the different definition of transmurality. A high correlation was found between MRI ejection fraction and MRI infarct size.

16:48 578. Myocardium Structural Remodeling with Relation of Infarct Location and Size in Porcine Model Using DTI Yin Wu1, 2, Hung Fat Tse3, Ed X. Wu1, 2 1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong; 2Dept. of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong; 3Dept. of Medicine, The University of Hong Kong, Pokfulam, Hong Kong

Myocardial infarction leads to altered myocardium geometry and mechanical function of left ventricle. Infarct size and location have been recognized as the determinants of LV remodeling. However, the effect of infarct location on cardiac remodeling is still controversial. In this study, CMR and DTI were performed to investigate the influence of infarct location and size on myocardium structural and fiber architectural alterations in porcine models. Results indicate that infarct size is the most dominant factor in the overall functional and structural degradation after myocardial infarction. However, both infarct size and location affect the myocardial fiber structural remodeling.

17:00 579. Modified Skeletal Myoblast Therapy for Cardiac Failure Using AAV SDF1 Bijoy Thattaliyath1, Faris Al-Mousily1, Sean Germain1, Christina A. Pacak1, Stacy Porvasnik1, Yoshihisa Sakai1, Melissa A. Lewis1, Glenn A. Walter, Barry J. Byrne1 1University of Florida, Gainesville, USA

This study was done to evaluate the transplantation of Adeno-associated viral mediated SDF1á modified human myoblast in surgically induced cardiac failure in nude rats. Cardiac MRI was done to evaluate functional recovery and the changes in cardiac wall dimensions following transplant. The main findings of this study are that: 1.SDF1 modified myoblasts are more effective in the improvement of left ventricular function. 2. Myoblasts can be efficiently labeled with superparamagnetic iron oxide particles and followed non-invasively to better understand the cell distribution after transplantation. The improvement in cardiac function can be attributed to the improved contractility, stem cell recruitment and angiogenesis in the infarcted myocardium.

17:12 580. Spiral Cine DENSE MRI at 7T for Quantification of Regional Function in the Mouse Heart Xiaodong Zhong1, Robert L. Janiczek1, Brent A. French1, Rene J. Roy1, Christopher M. Kramer1, Craig H. Meyer1, Frederick H. Epstein1 1University of Virginia, Charlottesville, Virginia , USA

Due to limited SNR, DENSE imaging in mice at 4.7T has previously been limited to a single (usually end systolic) cardiac phase. This study developed a spiral cine DENSE method on a 7T scanner with adequate SNR for high-resolution 2D cine DENSE imaging of the mouse heart in 6-8 minutes per slice. These methods allow for the routine use of cine DENSE for the assessment of 2D regional contractile function in mouse models of heart disease, as the data acquisition time is now reasonable with respect to typical acquisition times for other imaging sequences in mice.

17:24 581. MR Study of Postnatal Development of Left Ventricular Myocardium Structure and Function in Rats Yin Wu1, 2, Ke Xia Cai1, 2, Kyle Ho Yiu Cheng1, 2, Ed X. Wu1, 2 1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong; 2Dept. of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong

Development of heart is known to be essential for all organs growth. Numerous studies have been performed to investigate the growth of cardiac myocytes during postnatal period. However, development of myocardial fiber structure, which plays key role in cardiac function, remains to be explored. In current study, CMR and DTI study were performed to examine the myocardium structural maturation concurrent with the cardiac function development in postnatal rats. The results reveal that significant changes in myocardial fiber quality and helical structure mostly occur during the first 28 days. Furthermore, DTI analysis provides a potentially valuable tool to assess the microscopic changes in cellular morphology in heart.

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17:36 582. Evaluation of Statin Therapy in a Rabbit Model of Aortic Valve Sclerosis Using High Resolution MRI Amanda M. Hamilton1, 2, Kyle A. MacLean1, Maria Drangova1, 2, John A. Ronald1, 2, Brian K. Rutt1, 2, Derek R. Boughner1, 2, Kem A. Rogers1 1University of Western Ontario, London, Canada; 2Robarts Research Institute, London, Canada

Aortic valve sclerosis (AVS) is a prevalent disease with severe clinical consequences but no effective preventative therapy. We propose that MRI can be used to identify AVS early in the disease process at which time pharmaceutical therapies including statins could cause significant improvements. AVS was induced by cholesterol feeding in a rabbit model of the disease for 15 months and progression was monitored with MRI. At 15 months rabbits were subdivided into 5 treatment groups and monitored for an additional 15 months. Initial findings suggest statin therapy modulates the progression of AVS.

17:48 583. Regional OEF Determination with the BOLD Effect in Normal and Stenotic Dogs Kyle Stephan McCommis1, Benjamin Edward Northrup1, Haosen Zhang1, Robert J. Gropler1, Jie Zheng1 1Washington University School of Medicine, St. Louis, Missouri, USA

In this project, we used a black blood T2 method to determine the oxygen extraction fraction (OEF) during hyperemia in both normal dogs and dogs with a coronary artery stenosis. In both normal dogs and normal regions of the stenotic dogs, the OEF is dramatically reduced during Dipyridamole-vasodilation. Stenotic regions do not show these significant decreases associated with Dipyridamole, and the effect is attenuated with the stenosis severity. Dobutamine-hyperemia induces very little change in myocardial OEF in normal or stenotic regions. With this MR method, regional OEF changes caused by stenoses and pharmacologic-induced hyperemia can be readily identified.

Breast MRI: Optimizing & Predicting Outcomes Room 716 A/B 16:00-18:00 Chairs: Eva C. Gombos and Donald B. Plewes

16:00 584. NMR Shutter-Speed Discrimination of Malignant and Benign Breast Tumors Using ROI Data Xin Li1, Wei Huang2, Elizabeth A. Morris2, Luminita A. Tudorica3, William D. Rooney1, Ya Wang2, Jingang Xu1, Charles S. Springer, Jr. 1 1Oregon Health & Science University, Portland, USA; 2Memorial Sloan Kettering Cancer Center, USA; 3State University of New York at Stony Brook, USA

Dynamic-Contrast-Enhanced (DCE) MRI data were acquired from the lesions of 22 breast cancer patients, who had been screened positive by institutional protocols, but before biopsy and pathology analyses were performed. The data were subjected to pharmacokinetic analyses by both the Standard Model (SM) and the Shutter Speed Model (SSM). For ROIs circumscribing every one of the 15 lesions subsequently proven benign, the SM returned essentially the same value for Ktrans (a measure of CR extravasation rate) as the SSM. However, for every one of the 7 malignant tumors, the SM underestimated Ktrans. This allows complete separation of malignant from benign tumors.

16:12 585. Effect of the Spatial Resolution of A-Priori Data on the Quality of Single-Point Dixon Fat-Water Images Elizabeth Ramsay1, Donald Plewes1 1Sunnybrook Health Sciences Centre, Toronto, Canada

In this work, the effect of reducing the spatial resolution of the a priori phase information on Single-Point Dixon (SPD) images is examined, considering both noise performance and the quality of the fat-water separation. Decreasing the spatial resolution of the a priori images improves the noise properties of fat-water images, as well as reducing acquisition time. Human and phantom studies show that is possible to reduce the size of the acquisition matrix for the phase mapping scans to about 64x64 (voxel size 3mm) without compromising the quality of fat-water separation.

16:24 586. BOLD Contrast in the Breast at 3T Rebecca Rakow-Penner1, Laura Pisani1, Bruce Daniel1, Stephanie Oberfoell1, Christine Law1, Gary H. Glover1 1Stanford University, Stanford, California , USA

BOLD contrast imaging applied to breast tumors may provide useful clinical information on tumor oxygenation. Before studying tumors, we are developing a robust method for measuring BOLD contrast in healthy breast tissue at 3T. The method includes heart saturation to diminish cardiac motion artifact, along with corrections for respiratory motion and cardiac pulsation. A rapid multi-interleave spiral sequence is used to acquire the images. Results indicate that in healthy breast tissue that there is an inverse correlation between BOLD contrast and oxygenation.

16:36 587. Multi-Frequency Off-Resonance Correction and Water/Fat Separation for Spiral Breast Imaging Kristin L. Granlund1, 2, Brian A. Hargreaves1 1Stanford University, Stanford, California , USA

Off-resonance is a problem in spiral imaging because it causes image blurring and water/fat separation to fail. The problem may be severe when imaging over large volumes, such as in bilateral breast MRI. This project simultaneously corrects for off-resonance and performs water/fat separation using a multi-frequency reconstruction for 3D stack-of-spiral breast images with multiple echo times.

16:48 588. 3-D Tracking of the Mammary Ductal Tree Using Diffusion Tensor MR Imaging Erez Eyal1, Edna Furman-Haran1, Hadassa Degani1 1Weizmann Institute of Science, Rehovot, Israel

Mammary malignancies typically develop from the ductal epithelial cells, and spread within the ducts. Consequently, the ductal structures are an important area of investigation of both normal breast development and malignant breast transformation. Our aim is to develop an MRI method for tracking the spatial anisotropic diffusion of the water in the breast ducts and thereby map the ductal tree. The preliminary results show that diffusion in the mammary tissue has an anisotropic nature and that the orientation of the primary diffusion direction indicates that the tube-like micro structure of the ductal system can be tracked by DT-MRI

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17:00 589. Can Contrast-Enhanced MRI Be Used to Identify Those Breast Tumors at High-Risk for Disease Recurrence with High Specificity Even Prior to Preoperative Chemotherapy? Ka-Loh Li1, Savannah C. Partridge2, Bonnie N. Joe1, Jessica Gibbs1, Ying Lu1, Evelyn Proctor1, Laura Esserman1, Nola M. Hylton1 1University of California, San Francisco, San Francisco, USA; 2University of Washington, Seattle, Washington, USA

This study aimed to evaluate the predictive value of high spatial resolution signal enhancement ratio (SER) MR imaging performed prior to neoadjuvant chemotherapy in patients with breast cancers. The major finding was that breast tumor volume calculated from the number of voxels with high SER value and the volume (in voxels) of cancerous breast tissue infiltrating into the parenchyma (Such infiltrating voxels were of low SER) were important predictors of recurrence. 6/10 of patients with early recurrence (within 1.6 years) and 6/9 of deceased patients were identified. This study demonstrated the potential of pre-neoadjuvant chemotherapy contrast-enhanced MRI in predicting disease recurrence.

17:12 590. Prediction of Long Term Breast Cancer Survival Using MR Metabolomics Tone Frost Bathen1, Beathe Sitter1, Hans Fjøsne2, David E. Axelson3, Steinar Lundgren1, 4, Ingrid S. Gribbestad1 1NTNU, Trondheim, Norway; 2St Olav Univeristy Hospital, Trondheim, Norway; 3MRi_Consulting, Kingston, Canada; 4St Olav University Hospital, Trondheim, Norway

MR metabolomics is the systematic study of MR visible small-molecules. Metabolite profiles of breast cancer tissue have been found to correlate to lymph node and hormone receptor status. In this study, breast cancer tissue from patients with invasive ductal carcinomas were analysed by HR MAS MRS. The spectra were further analysed in a supervised manner with Support Vector Machine, relating selected variables from the spectra to the actual survival status 4 years after surgery. This preliminary investigation suggests that MR metabolomics can predict long term breast cancer survival. Early identification of patients with poor prognosis may be important for the administration of more aggressive treatment and closer follow-up of this patient group.

17:24 591. Statistical Metrics to Determine When Water Exchange Should Be Incorporated Into DCE-MRI Analysis: Simulations and Experimental Breast Cancer Results Thomas Yankeelov1, E. Brian Welch2, Anuradha Chakravarthy3, Robert Lee3, Darla Freehardt3, Ingrid Mayer3, Ingrid Meszoely3, Mark Kelley3, Julie Means-Powell3, John C. Gore3 1Vanderbilt University, Nashville, USA; 2Philips Medical Systems, USA; 3Vanderbilt University, USA

We apply three statistical measures to determine when water exchange effects should be incorporated in DCE-MRI data analysis. Simulations predict that after ti becomes above ~0.1 s, the FXR model will be preferred and this is what is seen in the breast cancer data. We conclude that, at least in the case of human breast cancer, water exchange effects should be explicitly incorporated in the analysis of DCE-MRI data.

17:36 592. Combined 2D MR Spectroscopy and Dynamic Contrast Enhanced MRI for Breast Cancer Detection Scott Logan Lipnick1, Xiaoyu Liu1, Nanette DeBruhl1, M. Albert Thomas1 1University of California, Los Angeles, Los Angeles, California , USA

The reported specificity of DCE-MRI has been variable, ranging from 37% to 97%, resulting in many unnecessary biopsies of benign lesion. Studies of breast cancer cell lines and breast tumors have consistently shown that choline (Cho) is elevated in malignant lesions. Magnetic Resonance Spectroscopy (MRS) allows noninvasive measurements of the concentrations of metabolites such as Cho in human breast. The purpose of this pilot study was to combine the DCE breast MRI analysis with localized two-dimensional MR correlated spectroscopy (2D L- COSY) in order to increase the specificity of breast cancer detection.

17:48 593. The Interaction of Gadolinium Based MR Contrast Agents with Choline Robert E. Lenkinski1, Mostafa Elian1, Xiaoen Wang1, S Nahum Goldberg1 1Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA

There is increasing interest in applying proton MRS to increase the specificity of characterizing breast lesions. The most common approach is to employ DCEMRI to identify suspicious lesions followed by localized proton MRS to determine either the presence of choline containing compounds or their absolute concentrations. The implicit assumption is that that the administration of a Gadolinium based contrast agent has little or no effect on the choline resonance. We report both in vitro and in vivo investigations of the effects of six commercially available contrast agents on the choline resonance. All of the negatively charged chelates showed significant effects.

Advanced MRS Localization & Imaging Methodology Room 701 A 16:00-18:00 Chairs: Roland Kreis and M. Albert Thomas

16:00 594. Sensitivity Encoded VAPOR-FIDLOVS at 7T: Mapping the Hidden Metabolites Anke Henning1, Alexander Fuchs1, James B. Murdoch2, David Foxall2, Peter Boesiger1 1University and ETH Zurich, Zurich, Switzerland; 2Philips Medical Systems, Cleveland, USA

For MRSI acquisition at 7T direct acquisition of the Free Induction Decay Localized by Outer Volume Suppression (FIDLOVS) is proposed to minimize SNR loss due to short T2 relaxation times. To that, a broadband frequency-modulated excitation pulse for slice-selection and a numerically optimized outer-volume-suppression scheme, which considers T1 relaxation of skull lipid, B1 inhomogeneity, saturation band crossing and is based on broadband PPR-pulses, for in-plane localization are applied. The resulting signal-to-noise ratio (SNR) and spectral resolution enable mapping of 15 metabolites. The high SNR is also the base for highly spatially resolved metabolite mapping accelerated by sensitivity encoding.

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16:12 595. Single-Shot Proton MR Spectroscopic Inverse Imaging Fa-Hsuan Lin1, 2, Shang-Yueh Tsai2, Yi-Ru Lin3, Ricardo Otazo4, Graham Wiggins1, Lawrence Wald1, John Belliveau1, Stefan Posse4 1Massachusetts General Hospital, Charlestown, Massachusetts, USA; 2National Taiwan University, Taipei, Taiwan; 3National Taiwan University of Science and Technology, Taipei, Taiwan; 4Univesity of New Mexico, Albuquerque, New Mexico, USA

A proton spectroscopic inverse imaging (SInI) acquisition and reconstruction protocol is introduced to measure 2-dimensional spectroscopic maps in a single excitation with high spectral resolution. Combining with echo-planar readout for spectral and 1D spatial information, we use the solution of the minimum-norm estimate (MNE) inverse problem along the other spatial dimension from all channels of a coil array. Feasibility of short TE proton MRSI was demonstrated on 3 T scanners equipped with a 32-channel array. This method enables flexible tradeoff between phase encoding and parallel imaging to maximize spectral width for applications in dynamic single-shot MRSI.

16:24 596. Lactate-Discriminating Echo-Planar Spectroscopic Imaging at 7 T Yoshitaka Bito1, Koji Hirata1, Toru Shirai1, Yukari Yamamoto1, Yoshihisa Soutome1, Toshihiko Ebisu2, Masahiro Umeda3, Yuko Kawai3, Toshihiro Higuchi3, Chuzo Tanaka3 1Hitachi, Ltd., Kokubunji-shi, Japan; 2Nantan General Hospital, Japan; 3Meiji University of Oriental Medicine, Japan

A fast lactate-discriminating echo-planar spectroscopic imaging (EPSI) technique suitable for 7-T MRI is developed. The technique uses just a single TE measurement for acquiring lactate-discriminated images, in which the TE is chosen to shift the echo peak of a lactate signal away from that of an overlapping lipid signal. The optimum TE at 7 T is calculated so that the lipid signal is sufficiently suppressed while the lactate signal is not attenuated so much. Acquisition of discriminated lactate images is demonstrated by applying this technique to a phantom and a rat.

16:36 597. Diffusion Weighted Spectroscopy: A Novel Approach to Determine Macromolecule Resonances at 14T Nicolas Kunz1, Cristina Cudalbu1, Vladimir Mlynarik1, Stéphane V. Sizonenko, Rolf Gruetter1, 2 1Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; 2University of Lausanne and Geneva, Switzerland

Quantification of the neurochemical profile by 1H-MRS critically depends on the estimation of the contribution of macromolecule resonances to the spectrum. As the linewidth of macromolecules does not increase with B0, the resonances attributed to macromolecules are increasingly difficult to distinguish from those of coupled spin systems. Due to heterogeneity of T1, in the metabolite-nulled spectra residuals attributed to metabolites are still observed. The study shows that an IR 1H-MRS sequence combined with diffusion weighting allows near-complete removal of metabolites signals and excellent definition of the spectral contribution of macromolecules due to one order of magnitude smaller ADC of macromolecules.

16:48 598. Superresolution Parallel Spectroscopic Imaging Ricardo Otazo1, Fa-Hsuan Lin2, Graham Wiggins2, Ramiro Jordan1, Stefan Posse1 1University of New Mexico, Albuquerque, New Mexico, USA; 2Massachusetts General Hospital, Boston, Massachusetts, USA

Standard parallel imaging may produce artifacts when applied to MR spectroscopic imaging (MRSI) due to coil sensitivity variation within the typical large voxels in low spatial resolution MRSI. In this work, a novel approach for accelerating the spatial encoding process of MRSI known as Superresolution SENSE (SURE-SENSE) is presented. Acceleration is performed by acquiring the low spatial resolution representation of the object being imaged and intra-voxel reconstruction is performed using coil sensitivity maps acquired with higher target spatial resolution. The method is particularly suitable for array coils with a large number of small elements that present stronger sensitivity variation. We show feasibility of the method for human brain MRSI using Proton Echo Planar Spectroscopic Imaging (PEPSI) and a 32-channel receiver array coil.

17:00 599. Fast Spectroscopic Imaging Using Uniform Wideband Parallel Excitation on 7T Borjan Aleksandar Gagoski1, Kawin Setsompop1, Vijay Alagappan2, Franz Schmitt3, Ulrich Fontius3, Andreas Potthast4, Lawrence Wald2, 5, Elfar Adalsteinsson1, 5 1Massachusetts Institute of Technology, Cambridge, Massachusetts, USA; 2MGH, Charlestown, Massachusetts, USA; 3Siemens Medical Solutions, Erlangen, Germany; 4Siemens Medical Solutions, Charlestown, Massachusetts, USA; 5Harvard-MIT Division of Health Sciences and Technology, Cambridge, Massachusetts, USA

In this work we combine spiral CSI readouts with parallel RF transmission to mitigate B1+ inhomogeneities. We limit this initial demonstration to the low flip-angle domain where excitation k-space analysis holds, and apply “spokes”-based slice selective RF design to an eight channel transmit system at 7T. The 8 transmit channels enable reduced-duration, slice-selective RF pulses that implement excellent wide band B1+ mitigation over a 600 Hz bandwidth. The goal of this work is to demonstrate efficient spiral CSI encoding with B1+-mitigated spatial-spectral excitation over a spatial FOV and frequencies of interest for 1H brain spectroscopic imaging.

17:12 600. Parallel Spectroscopic Imaging Reconstruction with Arbitrary Trajectories Using K-Space Sparse Matrices (KSPA) Meng Gu1, Chunlei Liu1, Daniel Spielman1 1Stanford University, Stanford, USA

Parallel reconstruction has been successfully applied to magnetic resonance spectroscopic imaging to reduce scan times. To reconstruct undersampled MRSI data with arbitrary k-Space trajectories, image-domain based iterative-SENSE algorithm and k-Space based PARS algorithm have been proposed at costs of long computing times. In this abstract, a new k-Space-domain based parallel spectroscopic imaging reconstruction with arbitrary trajectories using sparse matrices is applied to MRSI with spiral trajectories. It achieves MRSI reconstruction with reduced computing times. The results are demonstrated in an in-vivo study. Results very similar to that reconstructed with fully sampled spiral k-Space data are obtained with different reduction factors.

17:24 601. Reduction of Acquisition Time in Magnetic Resonance Spectroscopic Imaging Using 3D Wavelet Encoding Method: Comparison to Chemical Shift Imaging Richard Young1, Hacene Serrai1 1National Research Council Institute for Biodiagnostics, Winnipeg, Canada

This work describes the extension of the wavelet encoding method in MRSI from 2 dimensions to 3 dimensions. The obtained in-vivo results demonstrate the usefulness of the wavelet encoding method in reducing the acquisition time as compared to CSI. In addition, wavelet encoding appears to preserve the spatial distribution better than the CSI (phantom results not shown). As expected a reduction in signal-to-noise ratio is noticed in wavelet encoding; however, this reduction is minimum.

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17:36 602. Voxel Shift and Interpolation for Hadamard-Encoded MR Images Lazar Fleysher1, Roman Fleysher1, Songtao Liu1, Oded Gonen1 1NYU School of Medicine, New York, New York, USA

While spatial Fourier gradient phase-encoding and spatial Hadamard radio-frequency encoding are two established MR localization techniques, the absence of voxel-shift and interpolation post-processing algorithms for the latter has always placed it at a discouraging disadvantage. In this paper we present a method for voxel-shift and interpolation of Hadamard-encoded data.

17:48 603. Spectroscopic Imaging with Volume Selection by Unpaired Adiabatic π Pulses: Theory and Application Julien Valette1, Jang-Yeon Park1, Olli Gröhn1, Kamil Ugurbil1, Michael Garwood1, Pierre-Gilles Henry1 1CMRR, University of Minnesota, Minneapolis, Minnesota, USA

In spectroscopy, volume selection can be advantageously achieved using adiabatic π pulses, which enable high bandwidth and B1 insensitivity. In order to avoid the generation of non-linear phase profiles, these pulses are usually used in pairs. However, in the context of spectroscopic imaging, a high enough spatial resolution may limit phase dispersion within each pixel when using only one pulse per selected spatial dimension, yielding a reduced TE and reduced power deposition. In this work, the feasibility of this approach is explored theoretically and experimentally, using a new adiabatic sequence named Pseudo-LASER in the rat brain at 9.4 T.

Muscle: Blood Flow & Physiology Room 717 A/B 16:00-18:00 Chairs: Klaus Scheffler and Michael B. Smith

16:00 604. Dynamic BOLD MRI of Calf and Foot Muscles Markus Klarhöfer1, Sebastian Kos2, Markus Aschwanden2, Augustinus Ludwig Jacob2, Klaus Scheffler1, Deniz Bilecen2 1University of Basel, Basel, Switzerland; 2University Hospital Basel, Basel, Switzerland

Purpose was to evaluate the feasibility of interleaved MR BOLD imaging in calf and foot muscles for the examination of blood supply of most peripheral tissues. 15 healthy volunteers underwent a short term ischemia / reactive hyperemia experiment. Simultaneous T2* mapping was possible with a temporal resolution of 1 second. Reactive hyperemia led to higher and faster T2* changes in m. soleus of the calf than in m. adductor hallucis of the foot. However, further studies have to clarify, if disorders in the vascular periphery cause significant changes of the T2* evolution in foot muscles during a cuff compression paradigm.

16:12 605. Hyperemic Flow Heterogeneity in Human Leg Muscle: An MRI Study Using Arterial Spin Labeling Wen-Chau Wu1, 2, Jiongjiong Wang1, John A. Detre1, Felix W. Wehrli1, Emile Mohler1, Sarah Ratcliffe1, Thomas F. Floyd1 1University of Pennsylvania, Philadelphia, USA; 2National Taiwan University, Taipei, Taiwan

We report the results of the application of continuous ASL (CASL) to systematically study perfusion differences between all major muscle groups in the calf. Results show that the hyperemic response to a 5-min ischemia is significantly larger in the deep flexor and soleus muscle than more superficial muscles. The finding correlates with the fiber composition of muscles. CASL proves to be able to detect the flow heterogeneity between muscle groups in human extremities. The ability to reliably measure heterogeneity may help understanding the vascular/metabolic mechanisms in skeletal muscle and possibly provide diagnostic information for the assessment of peripheral vascular disease.

16:24 606. Perfusion Tensor Imaging of Human Skeletal Muscle Kun Lu1, Eric C. Wong1, Lawrence R. Frank1, 2 1University of California San Diego, La Jolla, USA; 2VA, La Jolla, USA

The ability to non-invasively measure tissue perfusion is critical for assessing the physiological functions of human skeletal muscle in both healthy and disease states. The traditional techniques to measure tissue perfusion in human muscle are invasive and measure only bulk properties which do not render information on either spatial or temporal heterogeneity. Velocity selective arterial spin labeling (VSASL) MRI has been shown previously to be sensitive to muscle perfusion in humans [1], but does not allow a full exploration of important properties associated with the muscle perfusion, such as perfusion anisotropy and perfusion directions. Perfusion Tensor Imaging (PTI) was proposed in 2004 by Frank and Wong [2] in a study of perfusion anisotropy in the human brain, where VSASL was applied with a spherical velocity encoding scheme similar to that used in diffusion tensor imaging (DTI). The perfusion measurements can then be characterized by a perfusion tensor (P), analogous to the diffusion tensor in DTI, from which the estimates of the mean perfusion, fractional perfusion anisotropy and principle perfusion direction can be derived. This study demonstrates that PTI can also be used to measure perfusion properties of human skeletal muscle.

16:36 607. Mapping Functional Electrical Stimulation in Denervated Thigh Muscles of Paraplegic Patients with T2 Parameter Imaging Martin Meyerspeer1, 2, Thomas Mandl1, Martin Reichel1, Winfried Mayr1, Christian Hofer2, Helmut Kern3, Ewald Moser1 1Vienna Medical University, Vienna, Austria; 2Wilhelminenspital Vienna,, Vienna, Austria; 3Wilhelminenspital Vienna, Vienna, Austria

Functional electrical stimulation (FES) for paraplegic patients, with the long-term goal of restoring muscle function, has several positive therapeutic effects. In denervated muscle, FES induced activation follows the electrical field which can be modelled in simulations.For verifying these models, maps of relative T2 change induced by FES were calculated: T2 parameter images were acquired using multi-slice multi-spin-echo MRI before and after FES in 9 denervated paraplegic patients and 3 healthy subjects. Images acquired pre and post exercise were realigned and normalised.Results show that the training effect f FES of denervated muscles can be visualised by T2 parameter images.

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16:48 608. Implementation of FAST-MRS in Mouse Permits the Rapid Assessment of Muscle ATP Synthesis In-Vivo Douglas E. Befroy1, Roberto Codella1, Gerald I. Shulman1, 2, Douglas L. Rothman1 1Yale University School of Medicine, New Haven, Connecticut, USA; 2Howard Hughes Medical Institute, New Haven, Connecticut, USA

The emergence of many transgenic mouse models with modulated muscle gene expression offers vast potential for the investigation of muscle metabolism. However, the application of the conventional saturation-transfer (CST) technique to assess metabolic reaction rates in mouse has been restricted by the small amount of muscle tissue available for MRS, necessitating very long experimental durations for a full CST experiment. We demonstrate that implementation of the Four-Angle Saturation Transfer (FAST) technique in mouse offers a rapid and practical alternative to CST for measuring muscle ATP synthesis in-vivo.

17:00 609. Detection of Residual Dipolar Couplings by 2D MRS Techniques in Skeletal Muscle S. Sendhil Velan1, Kartik Narasimhan1, Rolf F. Schulte2, Ali Bahu1, Richard G. Spencer3, Raymond R. Raylman1, Michael Albert Thomas4, Stephen E. Alway1 1West Virginia University, Morgantown, USA; 2GE Global Research, Munich, Germany; 3NIH/National Institute on Aging, Baltimore, USA; 4University of California, Los Angeles, Los Angeles, USA

In this study we employed localized 2D MRS approaches for detecting both J and residual dipolar couplings in skeletal muscle. The cross peaks in L COSY and J PRESS spectra can be generated by either J couplings usually observed in isotropic liquids, but normally not varying in size, or direct dipole-dipole interaction, only observable in oriented media. The residual dipolar couplings vanished in L COSY and collapsed in J PRESS spectra when the angle between the internuclear vector and the external magnetic field is 54 . Our results agree with the hypothesis that the elongated spaces between the actin and myosin chains hinder the creatine molecule from isotropic tumbling.

17:12 610. Metabolic Adaptations in Skeletal Muscle in the Early Stage of Insulin Resistance Measured in Vivo by 1H and 31P MRS Nicole M.A. van den Broek1, Henk MML De Feyter1, Klaas Nicolay1, Jeanine J. Prompers1 1Eindhoven University of Technology, Eindhoven, Netherlands

Literature suggests decreased mitochondrial oxidative capacity and intramyocellular lipid (IMCL) accumulation might be a major risk factor to develop insulin resistance. Skeletal muscle oxidative capacity and IMCL content in a rat model of early, lifestyle-induced insulin resistance was investigated using in vivo 1H and 31P MRS. After 2 weeks high-fat diet, Wistar rats were insulin resistant and had elevated IMCL levels compared to controls. Remarkably, τPCr is decreased in the insulin resistant rats. This means mitochondrial dysfunction does not play a role in the early stage of insulin resistance in a validated animal model of lifestyle-induced insulin resistance.

17:24 611. Mitochondrial Ultrasensitivity to ADP Explains Muscle Energetics During Recovery from Exercise Jeanine J. Prompers1, Nicole M.A. van den Broek1, Klaas Nicolay1, Jeroen A.L. Jeneson1 1Eindhoven University of Technology, Eindhoven, Netherlands

The recent discovery of extensive and dynamic protein phosphorylation in the mitochondrial matrix has rekindled the debate on the mechanistic underpinnings of energy balance in the active mammalian cell. We have previously reported evidence that the mitochondrial sensitivity to ADP may well be central to cellular energy balance. Here, we report new evidence in the form of rich 31P NMR spectroscopy data sets of ATP metabolism in human skeletal muscle and quantitative analysis of the post-exercise recovery state confirming our hypothesis that mitochondria are ultrasensitive to variations in the cytosolic concentration of the ATP hydrolysis product ADP.

17:36 612. High Energy Phosphate Metabolism in Primary Biliary Cirrhosis (PBC) Patients Monitored by 31P Magnetic Resonance Spectroscopy: Abnormalities in PH Handling Kieren Grant Hollingsworth1, Julia L. Newton1, Roy Taylor1, David E. Jones1, Andrew M. Blamire1 1Newcastle University, Newcastle Upon Tyne, UK

Primary Biliary Cirrhosis is an autoimmune liver disease with 50% of patients suffering profound, debilitating fatigue. This study uses phosphorus spectroscopy to non-invasively probe the concentrations of high-energy phosphates during a plantar flexion exercise. 8 healthy control subjects, 8 PBC patients without fatigue and 7 PBC patients with significant fatigue were put through two 3 minute periods of exercise, with loads of 25% and 35% of maximum voluntary contraction. Several significant abnormalities in pH and mitochondrial handling were found amongst the PBC patients, some of which affected all PBC patients and others which were restricted to the fatigued PBC patients.

17:48 613. Combined 31P MRSI and MRI Shows Distinct Abnormalities in Affected Muscles in Facioscapulohumeral Muscular Dystrophy Hermien E. Kan1, Dennis W.J. Klomp1, Marielle Wohlgemuth1, Tom W.J. Scheenen1, George W. Padberg1, Arend Heerschap1 1Radboud University Nijmegen Medical Center, Nijmegen, Netherlands

Facioscapulohumeral muscular dystrophy (FSHD) is characterized by asymmetric dysfunctioning of individual muscles. We used a combined approach of MRI and 31P MRSI to characterize anatomic and metabolic differences between affected and apparently non-affected muscles. We show, for the first time, dedicated application of 31P MRSI in affected and non-affected muscles in FSHD showing increased tissue pH and decreased PCr/ATP in affected muscles. Interestingly, non-affected muscles show no abnormalities, indicative of normal metabolism. It is unknown if this is also the case in other muscular dystrophies, as these are commonly studied by unlocalized 31P MRS

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Case-Based Teaching III: Cardiovascular Imaging Room 701 B 16:00 - 18:00 Chairs: Vivian S. Lee and Stefan G. Ruehm

Educational Objectives: Upon completion of this course, participants should be able to:

• Define the role of flow quantification techniques for cardiovascular MRA; • Select appropriate imaging protocols for the diagnosis of ischemic and non-ischemic heart disease; and • Predict the roles of imaging strategies based on non-contrast, contrast-enhanced, and time-resolved MR angiographic techniques for the

diagnosis of cardiovascular pathologies.

16:00 MRA of Aorta and Carotid Arteries James C. Carr

16:30 Ischemic Heart Disease Jens Bremerich

17:00 MRA of Renal and Peripheral Arteries Scott B. Reeder

17:30 Non-Ischemic Heart Disease: A Focus on Technique Gautham Reddy

MR Physics and Techniques for Clinicians Hall F 16:00 - 18:00 Chairs: Frank R. Korosec and Joseph C. McGowan

Educational Objectives: Upon completion of this course, participants should be able to:

• Define and describe the fundamental principles of MR imaging, including the definition of spin magnetization, the Larmor relationship, relaxation phenomena, and the process of using the spin magnetization to produce an image;

• Explain imaging pulse sequences based upon spin and gradient echoes, including fast spin echo and echo planar techniques; • Design MR imaging protocols for diagnostic applications considering image contrast, spatial resolution, acquisition time, signal-to-noise ratio,

and artifacts; and • Describe the principles of parallel imaging, fat and water imaging, and diffusion imaging.

16:00 Imaging Features and SNR Frank R. Korosec 16:40 Ultrafast Imaging

Jeffrey Tsao 17:20 Parallel Imaging

Mark A. Griswold

Parallel Transmission Methods Hall G 16:00-18:00 Chairs: V. Andrew Stenger and Peter Ullmann

16:00 614. Young Investigator Award Finalist: Electrodynamic Constraints on Homogeneity and RF Power Deposition in Multiple Coil Excitations Riccardo Lattanzi1, 2, Daniel K. Sodickson3, Aaron K. Grant2, 4, Yudong Zhu5 1Harvard-MIT, Cambridge, Massachusetts, USA; 2Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA; 3New York University Medical Center, New York, New York, USA; 4Harvard Medical School, Boston, Massachusetts, USA; 5GE Global Research, Niskayuna, New York, USA

This work explores electrodynamic constraints on transmit homogeneity and SAR in the case of fully parallel transmission and RF shimming. Ultimate SAR was computed for various target excitation profiles on a transverse plane through the center of a homogeneous sphere. The behavior with respect to main magnetic field strength, object size and acceleration was investigated in the ultimate case, as well as in the case of finite coil arrays. Ideal current patterns resulting in the lowest possible SAR were calculated and, as expected, increasingly complex current distributions were observed at higher magnetic field strengths.

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16:20 615. Increasing Bandwidth of Spatially Selective Transmit SENSE Pulses Using Constrained Optimization David Otto Brunner1, Klaas Paul Pruessmann1 1University and ETH Zurich, Zurich, Switzerland

Although spatially selective multichannel transmission pulses can be shortened by means of k-space undersampling with respect to single channel pulses, their bandwidth is often too limited to cope with strong off-resonances or the requirements of MR spectroscopy at ultra-high fields. In this study, we exploit the formalism of spatial-spectral pulse design to increase the bandwidth and hence the robustness of such pulses. The pulse design problem is stated in a highly underdetermined fashion as a constrained optimization problem, searching for the best performing pulse within existing SAR and power limits.

16:32 616. Uniform Wideband Slab Selection with B1+ Mitigation at 7T Via Parallel Spectral-Spatial Excitation Kawin Setsompop1, Vijayanand Alagappan2, Borjan Gagoski1, Lawrence Wald3, Elfar Adalsteinsson1 1Massachusetts Institute of Technology, Cambridge, Massachusetts, USA; 2A. A. Martinos Center for Biomedical Imaging, MGH, Charlestown, Massachusetts, USA; 3A. A. Martinos Center for Biomedical Imaging, Department of Radiology, MGH, Charlestown, Massachusetts, USA

Parallel RF (pTx) designs based on small-flip-angle excitations with “spoke”-based trajectories efficiently mitigate large B1+ inhomogeneities at high field, but posess a narrow-band off-resonance response. Proton chemical shift imaging benefits from higher B0, but requires B1+ mitigation over both a specified bandwidth and a spatial FOV. This additional bandwidth constraint presents a challenge for past methods on water-only B1+ mitigations. We describe a general pTx spectral-spatial excitations, demonstrate the technique on a wideband slice-selective spoke excitation, and validated it on a water phantom using an 8-channel transmit array system on a 7T human MRI scanner.

16:44 617. Dual-Band RF Shimming at High-Field with Parallel Excitation Adam Bruce Kerr1, Maryam Etezadi-Amoli1, Hans-Peter Fautz2, Mika W. Vogel2, Patrick Gross2, Yudong Zhu3, John Mark Pauly1 1Stanford University, Stanford, California , USA; 2GE, Munich, Germany; 3GE, Albany, New York, USA

A significant problem with current design approaches for RF shimming using three-dimensional selective excitation is their lack of ability to adequately shim simultaneously over multiple resonances such as water and fat. A new dual-band approach is presented that resolves this issue and is demonstrated on an eight-channel parallel transmit whole-body 3T system.

16:56 618. Optimal Control Design of Phase-Relaxed Parallel Transmission RF Pulses for Arbitrary Flip Angles Dan Xu1, Kevin F. King1, Zhi-Pei Liang2 1General Electric Healthcare, Waukesha, Wisconsin, USA; 2University of Illinois at Urbana-Champaign, Urbana, Illinois, USA

Conventional parallel transmission RF pulse designs are limited in two aspects: 1) an overly restrictive flat phase profile of the desired magnetization is enforced, which may sacrifice the quality of the magnitude profile, and 2) only small-tip-angle pulses can be accurately designed. More elaborate designs have been proposed to address either one of the issues, but none of them addresses both. In this paper, we propose a new, spinor-based, optimal control method which is capable of designing parallel transmission pulses with optimal phase profile and arbitrary tip angle simultaneously. Bloch simulation results of dual-channel transmission of 90 degree RF excitation pulses for B1 inhomogeneity correction show significantly more homogeneous magnitude profile of the transverse magnetization than existing designs.

17:08 619. Mode Compression of Transmit and Receive Arrays for Parallel Imaging at 7T Vijayanand Alagappan1, 2, Kawin Setsompop3, Jonathan R. Polimeni1, Andreas Potthast4, Adam C. Zelinski3, Graham C. Wiggins1, Ulrich J. Fontius5, Franz Schmitt5, Elfar Adalsteinsson3, Lawrence L. Wald1 1Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, USA; 2Tufts University, Medford, Massachusetts, USA; 3MIT, Cambridge, Massachusetts, USA; 4Siemens Medical Solutions, Charlestown, USA; 5Siemens Medical Solutions, Erlangen, Germany

While increasing the number of array elements appears beneficial for both parallel transmission and reception, this approach is limited in practice, especially in the parallel transmit case. Forming linear combinations of array elements can transform the spatial modes of the array into a different basis set potentially capturing a majority of the sensitivity and acceleration capabilities in a subset of the channels. We develop a mode transformation of a 16 element 7T T/R strip-line array using a 16x16 Butler matrix and analyze both the Stripline and orthogonal Birdcage mode basis sets when truncated from 16 modes to 8. The birdcage basis set were found to be spatially orthogonal, gave a lower excitation error and had significant SNR benefits and acceleration capabilities compared to the stripline basis set.

17:20 620. In Vivo B1+ Inhomogeneity Mitigation at 7 Tesla Using Sparsity-Enforced Spatially-Tailored Slice-Selective

Excitation Pulses Adam Charles Zelinski1, Kawin Setsompop1, Vijayanand Alagappan2, Vivek K. Goyal1, Lawrence L. Wald3, 4, Elfar Adalsteinsson1, 4 1Massachusetts Institute of Technology, Cambridge, Massachusetts, USA; 2A. A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, USA; 3Harvard Medical School, Longwood, Massachusetts, USA; 4Harvard-MIT Division of Health Sciences & Technology, Cambridge, Massachusetts, USA

We design & demonstrate a 7-ms slice-selective pulse that mitigates B1+ inhomogeneity in the human brain at 7T without the use of a parallel transmission

system. First, a magnetization reset pulse is used to rapidly acquire a series of images. These images are then fit to an intensity equation to estimate B1+. A

sparsity-enforced spoke placement algorithm is then used to find a small set of spoke locations & weights that lead to a short, slice-selective mitigation pulse. Unlike a shimming approach, the B1

+ field is not flattened; rather, the gradient modulation of the excitation process produces a uniform magnetization.

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17:32 621. A Minimum SAR RF Pulse Design Approach for Parallel Tx with Local Hot Spot Suppression and Exact Fidelity Constraint Ingmar Graesslin1, Ferdinand Schweser1, Bjoern Annighoefer1, Sven Biederer2, Ulrich Katscher1, Kay Nehrke1, Henry Stahl1, Henk Dingemans3, Giel Mens3, Peter Börnert1 1Philips Research Europe, Hamburg, Germany; 2Lübeck University, Lübeck, Germany; 3Philips Medical Systems, Best, Netherlands

SAR is a limiting factor in high-field MRI. Parallel transmit systems are able to tailor E-fields via SAR optimized RF pulse design. Certain SAR optimal algorithms constrain a specific local region for SAR, which is generally insufficient for whole body imaging. In this paper, a SAR optimal RF pulse design approach is presented using a predefined excitation error as trade-off for minimizing SAR. Additionally, based on this approach, also a method for local hot spot reduction is presented. The concept was successfully validated by simulations and experiments via a graphic card-based (almost) real-time whole body local SAR calculation.

17:44 622. Single-Shot Z-Shim Technique Using Parallel Transmitters for Reduced Suscpetibility Artifacts Weiran Deng1, Fernando E. Boada 2, Victor Andrew Stenger 1

University of Hawaii, Honolulu, Hawaii, USA; 2University of Pittsburgh, Pittsburgh, Pennsylvania, USA

Susceptibility artifacts are major limitation in T2* weighted MRI such as BOLD fMRI. Z-shim techniques and 3D RF pulses have been proposed to mitigate the through-plane susceptibility artifact. However, z-shim techniques require multiple shots and 3D RF methods are complex with long pulse lengths. Parallel transmission methods have been proposed to reduce 3D RF pulse lengths, however, the current implementation of these techniques is computationally very challenging. We present a potentially simple parallel transmission method using time-shifted 1D sinc pulses for performing a single-shot z-shim. The method is shown to reduce susceptibility artifacts in T2* weighted images at 3T.

Study Group MR of Cancer Room 801 A/B 19:30 - 21:30

Study Group High Field Systems & Applications Room 718 A/B 19:30 - 21:30

Business meeting 19:30 Chair's report 19:40 Secretary's report 19:50 Discussion: Should 3T still be included in Study Group's brief? 20:05 Discussion: Rome Workshop issues: program and organization Mini-symposium: Optimal Contrast Sequences at 7T+. 20:15 William Rooney, Ph.D., Oregon Health and Science University, Portland, OR, USA 20:30 To be announced 20:45 To be announced 21:00 Oliver Speck, Ph.D., Otto-von-Guericke-University, Magdeburg, Germany 21:15 Panel discussion

Study Group MR Flow & Motion Room 714 A/B 19:30 - 21:30

19:30 Business Meeting New committee memebers New president of Flow & Motion Study Group Web site Flow & Motion workshop 2009? 19:40 Scientific Program Making Sense of Complex Flow David Steinman, Ph.D., University of Toronto, Toronto, Canada A Short Introduction to Vascular Flow Speaker To Be Announced

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Study Group White Matter Room 701 A 19:30 - 21:30

Welcome Chair: Greg Stanisz, Ph.D., Sunnybrook HSC/University of Toronto, Toronto, ON, Canada Study Group Business Information on the Workshop on Pathogenesis of White Matter Injury in Krakow Presentations on Unconventional White Matter Imaging Introduction Roland Henry, Ph.D., University of California, San Francisco, CA, USA 13C Imaging Brian Ross, M.D., Ph.D., Huntington Medical Research Institute, Pasadena, CA, USA

Study Group Molecular & Cellular Imaging Room 701 B 19:30 - 21:30

Ferritin as a reporter of gene expression Keren Ziv, M.Sc., Weizmann Institute of Science, Rehovot, Israel Reporter proteins for CEST imaging Michael McMahon, Ph.D., Johns Hopkins University School of Medicine, Baltimore, MD, USA Discussion Pretargeting for imaging receptors Dmitri Artemov, Ph.D., Johns Hopkins University School of Medicine, Baltimore, MD, USA Macromolecules and dendrimers for targeted imaging Zheng-Rong Lu, Ph.D., University of Utah Salt Lake City, Utah, USA Discussion

Study Group Psychiatric MRI/S Room 713 A/B 19:30 - 21:30

19:30 Introduction Chair: Stefan Posse, Ph.D., Associate Professor, Departments of Neurology, Electrical and Computer Engineering, and Physics and Astronomy, University of New Mexico School of Medicine, Albuquerque, NM, USA

19:45 Neurogenesis: What is it, what is the hype about, and is it even desirable?

Suzanna Becker, Ph.D., Professor, Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontario, CANADA 20:10 Preclinical Studies Examining the Role of Adult Neurogenesis in Affective Disorders

Robert Schloesser, Ph.D., Laboratory of Molecular Pathophysiology, Mood and Anxiety Disorders Program, National Institute of Mental Health

20:35 Stem cell tracking by imaging

Jeff Bulte, Ph.D., Professor, Department of Radiology, Director of Cellular Imaging, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA

21:00 MRS Measurement of Neuronal Progenitor Cells as potential in vivo markers of neurogenesis

Mirjana Maletic-Savatic, M.D., Ph.D., Assistant Professor of Neurology, School of Medicine, SUNY Stonybrook, Stonybrook, NY, USA 21:25 Closing Remarks Chair: Stefan Posse, Ph.D.

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Study Group Musculoskeletal Room 715 A/B 19:30 - 21:30

19:30 Welcome 19:30 Review of MRI development for OA over the past 20 years Bernard Dardzinski, Ph.D., BRIE Franchise Imaging Lead, Blue Bell, PA, USA 19:40 How is MRI viewed by the OA clinical and pharmaceutical communities? Jeffrey Evelhoch, Amgen Inc., Thousand Oaks, CA, USA 19:50 Why have we not proven the utility of MRI for OA? Part I: Resource limitations Charles Mamisch, M.D., University of Bern, Bern, Switzerland Part II: Paradigm and existing dogma limitations Deborah Burstein, Ph.D., Beth Israel Deaconess Medical Center, Harvard Institutes of Medicine, Boston, MA, USA 20:10 The OAI: Current status of data acquisition and analysis Gayle Lester, Ph.D., NIAMS/NIH Bethesda, MD, USA 20:20 Recommendations for future success: (Panel and audience discussion)

a. Delineation of concepts learned about OA from MRI data b. Potential new areas in MRI for OA research c. OAI: Potential data interpretation studies / additional acquisition protocols d. Resources needed to accomplish the above

21:00 Administrative

a. Election Results b. Announcements

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MORNING CATEGORICAL COURSE Safety Update Room 801 A/B 7:00 – 8:00 Chair: Penny A. Gowland

Educational Objectives: Upon completion of this course, participants should be able to:

• List the main interactions between the statis field and the sensory organs in humans; • List the main interactions between the static field and cells; • Explain the origins of the inhomogeneous temperature rise in the body due to exposure to the RF field from an MRI RF coil, and predict

situations likely to lead to an increased risk of RF burns; • Decide how to recommend whether it is safe to scan someone with an implant; • Identify the hazards associated with MR contrast agents, and contrast different types of agents in terms of the risk profiles; and; • Compare the regulatory position for MRI across the world.

07:00 Bioeffects of Static and Gradient Fields: Sensing the Static Field Paul M. Glover 07:30 Bioeffects of Static and Gradient Fields: Cellular Effects Junji Miyakoshi

MORNING CATEGORICAL COURSE Ultra-High Field MR in Humans Room 718 A 7:00 – 8:00 Chairs: Klaas Pruessmann and Lawrence L. Wald

Educational Objectives: Upon completion of this course, participants should be able to:

• Explain the importance of array technology for RF excitation and detection at ultra-high field, along with its basic modes of operation; • Distinguish different types of BOLD contrast in ultra-high-field fMRI and describe corresponding pulse sequences; • Name the key problems and their current solutions in ultra-high-field MRS; • List promising applications of ultra-high-field MR in and outside the brain and name their remaining limitations.

07:00 Susceptibility Effects and Phase Contrast Richard W. Bowtell 07:30 Ultra-High-Field Imaging Outside the Brain Ravinder R. Regatte

MORNING CATEGORICAL COURSE Absolute Beginners’ Guide to Anatomical and Functional MRI of the Human Brain Room 718 B 7:00 – 8:00 Chairs: Alan Connelly and Chloe Hutton

Educational Objectives: Upon completion of this course, participants should be able to:

• Identify the neuroanatomical and neurophysiological parameters which are accessible to MR measurement; • Describe the underlying physics of MR neuroimaging techniques; • Describe the data acquisition and analysis techniques most commonly used for anatomical and functional MRI of the brain; and • Recognize the potential value of advances such as parallel imaging, fast imaging techniques and high magnetic field strengths for imaging the

brain. 07:00 Absolute Beginner’s Guide to Functional MRI Peter A. Bandettini

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MORNING CATEGORICAL COURSE Clinical Science for Physicists and Engineers Room 714 A/B 7:00 – 8:00 Chairs: Vivian S. Lee, Tim Leiner, and Bachir Taouli

Educational Objectives: Upon completion of this course, participants should be able to:

• Identify basic anatomy and physiology of the central nervous system, kidney, liver, cardiac, vascular and musculoskeletal systems; • Describe the process and diagnosis of stroke and white matter formation and damage; • Explain kidney and liver anatomy and function, and how MRI can be used to evaluate these organs; • Discuss basic cardiac physiology and the consequences of coronary artery disease and heart failure; • Describe the process of bone and cartilage formation and degeneration; and • Appraise unmet clinical needs that could potentially be solved by physicists and engineers.

Heart: Anatomy, Function, Pathology, and Challenges 07:00 Coronary Arteries: What You Need to Know Tim Leiner 07:30 Heart Failure: What You Need to Know Bernd Wintersperger

MORNING CATEGORICAL COURSE Cardiovascular Molecular MR Contrast Agents: From Bench to Bedside Room 716 A/B 7:00 – 8:00 Chair: Peter Caravan

Educational Objectives: Upon completion of this course, participants should be able to:

• Define the specific challenges faced in molecular MRI and in particular explain the sensitivity limitations of MR contrast media; • List the different classes of contrast agents used and the strategies applied to enable molecular imaging with MR; • Identify molecular imaging agents being used in cardiovascular research; • Compare the different animal models used in cardiovascular molecular MRI and appraise the relative strengths of each; and • Describe two ways in which cardiovascular molecular MR imaging are being translated into clinical research.

07:00 Pushing the Contrast Sensitivity Envelope Silvio Aime 07:30 Molecular imaging using Multimodality (MR, PET, and CT) for Characterizing Atherosclerotic Plaque Zahi A. Fayad

MORNING CATEGORICAL COURSE Neuroimaging: What can clinicians learn from the animal model work? Room 701 A 7:00 – 8:00 Chairs: Pia C. Maly Sundgren and Annemie van der Linden

Educational Objectives: Upon completion of this course, participants should be able to:

• Describe the main MRI methods used in experimental studies to diagnose 1) Amyotrophic Lateral Sclerosis (ALS), 2) Stroke, and 3) Cerebral Amyloid Angiopathy (CAA), and the underlying rationale;

• Explain what is known about the underlying mechanism in ALS, stroke, and CAA and which type of MRI investigations could be used for (early) diagnosis of these diseases;

• List the main MRI methods used in the clinical setting to diagnose these diseases and the underlying principles behind them; and • Make the translate from what is – and can be – done in experimental studies on ALS, stroke, and CAA to what can be done clinically.

07:00 Cerebral Amyloid Angiopathy: Diagnosis through Experimental Work Thomas Mueggler 07:25 Cerebral Amyloid Angiopathy: Diagnosis in the Clinic Steven M. Greenberg 07:50 Discussion

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MORNING CATEGORICAL COURSE Clinical Application of Cardiovascular Imaging Room 701 B 7:00 – 8:00 Chairs: Georg Bongartz and Stefan G. Ruehm

Educational Objectives: Upon completion of this course, participants should be able to:

• Describe state-of-the-art MR techniques for cardiac imaging; • List the various approaches to the assessment of cardiac function, perfusion, and viability; • Interpret cardiac MRI in various pathologies; • Explain recent approaches to vessel wall and luminal vascular imaging; and • Describe typical problems in cardiovascular imaging, including artifacts.

Ischemic Disease 07:00 Global and Regional Function Matthias G. Friedrich 07:20 Myocardial Perfusion Juerg Schwitter 07:40 Myocardial Viability Peter Hunold

MORNING CATEGORICAL COURSE Cell Tracking Rom 713 A/B 7:00 – 8:00 Chair: Jeff W. M. Bulte

Educational Objectives: Upon completion of this course, participants should be able to:

• List at least four methods to label cells; • List disease models in which MRI cell tracking is an important tool; • Recognize which clinical trials have been performed and what is likely needed for future FDA approval; and • Identify what role interventional radiologists will play in the future.

Cell Tracking: Clinical Applications 07:00 MRI Cell Tracking: First Clinical Applications in Cancer Patients Jolanda de Vries

07:30 MRI Cell Tracking: What is Needed for Clinical Translation and Implementation? Adrian D. Nunn MORNING CATEGORICAL COURSE Hyperpolarization: How to Obtain and Use a 100,000-Fold Increase in Polarization Room 715 A/B 7:00 – 8:00 Chairs: John P. Mugler, III, and Brian K. Rutt

Educational Objectives: Upon completion of this course, participants should be able to:

• Describe “hyperpolarization,” that is, the physical process for generating nuclear polarization in certain gases or compounds that exceeds the thermal-equilibrium polarization achieved in typical MR scanners by several orders of magnitude;

• List the nuclei and compounds for which the hyperpolarized state has been achieved; • Identify the special requirements for MRI or MRS of hyperpolarized contrast media and describe pulse-sequence strategies that meet these

requirements; • List imaging and spectroscopy applications of hyperpolarized contrast media in animal models of disease; and • Implement hyperpolarized gas MRI in human pulmonary diseases for which it may improve detection and/or characterization compared to

current modalities.

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Hyperpolarized Gases: Physics and Methods 07:00 Polarization Physics: Noble Gases F. William Hersman 07:30 Acquisition Methods: Hyperpolarized Gases John P. Mugler III

MORNING CATEGORICAL COURSE Tissue Contrast in MSK MRI: From Physics to Physiology Room 717 A/B 7:00 – 8:00 Chairs: Bernard Dardzinski and Timothy J. Mosher

Educational Objectives: Upon completion of this course, participants should be able to:

• Describe the physical and molecular basis for T1, T2, T1p and MT contrast as they relate to collagen-rich tissues; • Identify the effects of tissue anisotropy on relaxation properties; • Apply understanding of mechanism of image contrast in musculoskeletal MRI to clinical and translational research applications; and • Describe the ultra-short TE and T1p techniques and potential clinical applications.

07:00 Ultra-Short TE Imaging: Techniques and Basis for Image Contrast Mark Bydder 07:30 MSK Clinical and Research Applications of UTE Imaging Christine Chung

OPENING SESSION Hall F/G 07:30 – 08:20 Chair: Vivian S. Lee, ISMRM President

08:00 YIA and Poster Award Presentations

2008 MANSFIELD LECTURE Hall F/G 08:05 – 08:45 Chair: Vivian S. Lee, ISMRM President

08:05 Direct Imaging of Short T2 Relaxation Components in Tissue Using Clinical MR Systems Graeme M. Bydder University of California San Diego Medical Center, San Diego, California, USA

PLENARY LECTURES: The Spectrum of New Hardware and How It's Changing Clinical Management Hall F/G 08:45-10:00 Chairs: Kim Butts Pauly and Lawrence L. Wald

8:45 623. The Spectrum of New Hardware Mark E. Ladd1 1Erwin L. Hahn Institute for MRI, Essen, Germany

The introduction of new magnetic resonance imager hardware and software has been continual since the introduction of MR into clinical imaging in the 1980’s. Areas of technological advancement include new magnet designs, gradient hardware, and radiofrequency coil technology. The goal of this talk is to review some of the latest advances in imager hardware and point to their potential for further advancing patient care.

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9:10 624. The Spectrum of New Hardware and How It's Changing Clinical Management, a Neuroradiologist's Perspective Clifford R. Jack1 1Mayo Clinic, Rochester, Minnesota, USA

The types of medical questions MRI will increasingly be asked to answer are related to chronic medical conditions which characterize an aging population. Implicit in this scenario is the notion that MRI must address increasingly subtle biological questions and must capture change over time on serial imaging studies. Consequently, MRI will in-creasingly need to resemble a quantitative laboratory test rather than primarily a tool for anatomic visualization. Designers of the next generation of MRI hardware should seek to maximize precision in addition to traditional considerations of SNR and efficiency.

9:35 625. The Spectrum of New Hardware and How It is Changing Clinical Management: Winfried Willinek1 1University of Bonn, Bonn, Germany

In the field of body MR imaging advances in technology include MR systems operating at higher field strengths, hybrid MR scanners, more powerful RF and gradient systems, multi-channel coils with parallel imaging and transmission capabilities, faster reconstruction algorithms, improved memory capacities, artefact correction and innovative sampling strategies. Functional and quantitative assessment of multiple anatomic areas in conjunct with high spatially and temporally resolved information enables the evaluation and diagnostic work-up of the entire patient instead of several body parts or target organs. This will help to reach the ultimate medical goal: improvement in clinical decision making and patient management.

Measurement of Cerebral Perfusion & Permeability Using Contrast Agents Room 801 A/B 10:30-12:30 Chairs: Fernando Calamante and Michael R. Smith

10:30 626. Optimal Location for Phase-Based Arterial Input Function Measurements Near the MCA for DSC-Perfusion MRI Egbert Jan Willem Bleeker1, M. A. van Buchem1, M. J.P. van Osch1 1Leiden University Medical Center, Leiden, Netherlands

Obtaining quantitative values for perfusion from DSC-MRI requires a correct AIF for deconvolution. Commonly the AIF is obtained in the vicinity of the MCA using the δR2

* derived from magnitude data, but δ φ, derived from the phase of the MR signal, proves to be a suitable candidate as well. This study provides the optimal locations for AIF measurements based on the phase signal by numerical simulations validated by phantom experiments.

10:42 627. Delay and Dispersion in DSC Perfusion Derived from a Vascular Tree Model Predicts ASL Measurements Peter Gall1, Esben Thade Petersen2, Xavier Golay2, Valerij Kiselev1 1University Hospital Freiburg, Freiburg, Germany; 2National Neuroscience Institute, Singapore, Singapore

CBF estimates are blurred by delay and dispersion of a bolus from an artery to the tissue. A cylinder with laminar flow conditions can approximate a blood vessel. Obeying a scaling rule, a tree composed of such cylinders can represent the vasculature. For each path within the tree a vascular transfer function can then be derived. ASL techniques are capable of measuring the transport function that describes the trespass trough major cerebral arteries. The theoretical vasculature model for the path evaluated in the ASL measurement in a volunteer can predict the measured transport function.

10:54 628. Correcting PWI-Based CBF Measurements for Arterial Input Function Partial Volume and Nonlinear Contrast Relaxivity: Comparison with a Xenon CT Gold Standard Greg Zaharchuk1, Roland Bammer1, Matus Straka1, Rexford D. Newbould1, Jean-Marc Olivot1, Michael Mlynash1, Maarten G. Lansberg1, Greg W. Albers1, Michael E. Moseley1 1Stanford University, Stanford, California , USA

Reasonable relative CBF images that correlate well with gold standard techniques such as O-15 water PET can be created from PWI bolus tracking experiments. A large problem is that the global CBF scaling factor varies significantly from patient to patient, such that absolute PWI-based CBF measurements are not reliable. This study examines whether corrections for AIF partial voluming and nonlinear bulk blood contrast relaxivity in single shot GE EPI PWI lead to improved CBF quantitation, by comparing with a gold standard xeCT method in patients with cerebrovascular disease.

11:06 629. Absolute Cerebral Blood Flow in Normal Volunteers: Correlation Between CT-Perfusion and Dynamic Susceptibility Contrast MRI Doerthe Ziegelitz1, Linda Knutsson2, Göran Starck3, Stig Holtås2, Mats Tullberg3 1Sahlgrenska University Hospital, Gothenburg, Sweden; 2Lund University Hospital, Sweden; 3Sahlgrenska University Hospital, Sweden

To improve the reproducibility of AIF registration and absolute CBF quantification in DSC-MRI at 1.5T, we rescaled the time integral by use of a venous output function. CBF estimates of 21 healthy, elderly volunteers, obtained by CT-perfusion and DSC-MRI on 2 consecutive days, were compared. DSC-MRI, calculated without the AIF time-integral correction, did not result in any significant correlation with CT-perfusion. The rescaled DSC-MRI showed fair to moderate correlation with CT-perfusion for the central grey matter and the whole brain. Our results indicate that the used method for correction of partial volume effects in DSC-MRI experiments is effective at 1.5T.

11:18 630. A Novel Vessel Segmentation Technique Based on Clustering of Dynamic First-Pass MR Imaging Parameters Kyrre Eeg Emblem1, 2, Baard Nedregaard1, John K. Hald1, David Scheie1, Atle Bjornerud1, 2 1Rikshospitalet, Oslo, Norway; 2University of Oslo, Oslo, Norway

Studies have shown that cerebral blood volume (CBV) maps derived from MR perfusion can improve glioma grading. A problem with any MR perfusion based glioma grading method is the need to exclude large vessels infiltrating the tumor region in order to avoid false positives due to the artificial CBV increase. We propose a novel vessel segmentation technique which uses several properties of the DSC response to automatically segment and remove macrovascular structures from CBV maps. Preliminary results suggest that this technique improves the diagnostic efficacy of glioma grading, especially for gliomas located in the middle cerebral artery (MCA) regions.

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11:30 631. Study of Injection Duration and Onset Time Uncertainty in Dynamic Contrast Enhanced MRI: A Comparison of a Reference Region Model with a Simple 2-Compartment Kety Model Yeng-Peng Liao1, Ing-Tsung Hsiao, Ho-Ling Liu 1 Chang Gung University, Tao-Yuan, Taiwan

This study is aimed to evaluate the influence of AIF shape and onset time in estimating the physiological parameters from T1-weighted DCE-MRI kinetic analysis in a reference region model (RRM), and compare its results to that from a simple Kety model (SKM) with sampled AIF. Conditions combining different SNRs, onset times, injection durations were simulated. The mean errors and coefficient of variation (CoV) of Ktrans,TOI were calculated for both methods. The results show that with the availability of stable Ktrans,RR , the RRM produces stable and smaller mean errors of Ktrans,TOI, and similar CoV as compared to those from SKM.

11:42 632. Incorporating the Effect of Capillary Transit Time in DCE-MRI Pharmacokinetic Analysis Hai-Ling Margaret Cheng1, 2 1The Hospital for Sick Children, Toronto, Canada; 2University of Toronto, Toronto, Canada

DCE-MRI quantification of pharmacokinetic parameters is subject to various sources of measurement errors and physiological unknowns. One unknown that has not been studied in DCE-MRI is the influence of a finite capillary transit time. Simulations show that longer transit times give rise to significant error in parameter estimates. A modification to the Tofts model is presented and is shown to substantially improve parameter accuracy in the presence of both transit time and bolus arrival delay. Accuracy is maintained in the transfer constant (Ktrans) and interstitial space (ve), and underestimation of the plasma volume (vp) is greatly reduced.

11:54 633. Correction of the T2* Influence on the Concentration Estimation of T1-Weigthed DCE-MRI Data Without Measuring T2* Michael Gerhard Kaul1, Gerhard Adam1 1University Medical Center Hamburg-Eppendorf, Hamburg, Germany

For pharmacokinetic analysis dynamic contrast enhanced (DCE)-MRI data is transformed from a signal enhancement to a Gadolinium related concentration scale. This work aims to minimize the error of ignoring the influence of T2* relaxation in spoiled T1-weighted gradient sequences without measuring T2*. This is accomplished by an easy to implement iterative algorithm. Its effectiveness is proved by simulated data for a first pass of Gd-DTPA in blood and tissue. Within several iteration steps a sufficient correction is achieved.

12:06 634. Comparison of Analysis Methods for DCE-MRI Data Via Impact on Sensitivity to Treatment Effect Edward Ashton1 1VirtualScopics, Inc., Rochester, New York, USA

It is commonly assumed that tracking of changes in vascular parameters using DCE-MRI requires conversion of the signal changes seen in tissues to Gd concentration. Recent studies have indicated that such conversion may be unnecessary using certain protocols, and may in fact increase measurement noise. Questions have also been raised regarding the advisability of measuring an arterial input function (AIF) from DCE-MRI data as opposed to assuming a single generalized population AIF. In this work we have assessed the impact of each of these decisions on the statistical confidence in study outcome using data from a Phase I clinical study.

12:18 635. Validation of a Dual Echo DSC-MRI Approach That Enables the Simultaneous Measurement of Blood Flow, Blood Volume and Ktrans C. Chad Quarles1, John C. Gore1, Thomas E. Yankeelov1 1Vanderbilt University, Nashville, Tennessee, USA

We recently proposed a dual echo DSC-MRI approach that removes EES T1 and T2* extravasation effects and enables the computation of R1 time curves. In this study we demonstrate that CBF and CBV measurements corrected for EES T1 and T2* leakage effects strongly correlate to those derived from a DSC study using an intravascular contrast agent. This correlation was much greater than that derived from uncorrected and T1 only corrected measurements. We also show that DSC and standard DCE measured R1 time curves are very similar and yield a high correlation between the derived Ktrans values.

New Contrasts: CEST, et al. Room 718 A 10:30-12:30 Chairs: Peter van Zijl and Elena Vinogradov

10:30 636. Imaging Acute Ischemic Tissue Acidosis Using a Relaxation-Compensated Multi-Slice Amide Proton Transfer (APT) MRI Phillip Zhe Sun1, Yoshihiro Murata2, Jie Lu2, 3, Xiao Ying Wang2, Eng H. Lo2, Alma Gregory Sorensen1 1A. A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, USA; 2Massachusetts General Hospital, Charlestown, Massachusetts, USA; 3XuanWu Hospital, Beijing, People's Republic of China

Amide proton transfer (APT) imaging is a variant of chemical exchange saturation transfer (CEST) imaging that has been shown capable of detecting acute ischemic tissue acidosis, and may serve as a surrogate metabolic imaging marker complementary to perfusion and diffusion MRI. Given that pathologies such as stroke and cancer are spatially heterogeneous, APT imaging with sufficient volume coverage is necessary in order to fully evaluate the diagnostic power. Using a 2-pool exchange model, we showed that the CEST contrast decrease after RF irradiation is governed by its intrinsic relaxation constant of bulk water. Here, we propose a fast volumetric APT imaging approach that acquires multi-slice CEST images immediately after a single long CW RF irradiation, and the relaxation-induced loss of APT contrast is compensated during post-processing. The proposed technique is verified by numerical simulation and validated with a tissue-like dual pH phantom. When translated to image acute animal stroke, the proposed technique detected heterogeneous distribution of PWI, pH and DWI lesions, permitting future study to fully elucidate the diagnostic value of pH-weighted APT MRI.

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10:42 637. Simultaneous 19F and 1H-CEST Technique for Improved Accuracy and Efficiency in Quantitative CEST Measurements Jochen Keupp1, Shelton D. Caruthers2, 3, Dirk Burdinski4, Sander Langereis4, Jeroen A. Pikkemaat4, Rolf Lamerichs4, Holger Gruell4, Samuel A. Wickline2, Gergory M. Lanza2, Patrick M. Winter2 1Philips Research Europe, Hamburg, Germany; 2Washington University, St. Louis, Missouri, USA; 3Philips Medical Systems, Andover, Massachusetts, USA; 4Philips Research Europe, Eindhoven, Netherlands

Responsive chemical-shift saturation transfer (CEST) agents have been developed for mapping of diagnostic parameters, like local pH for oncology applications. Because the 1H-CEST signal strength depends as well on the physiological parameters as on agent concentration, a common challenge is the determination of the local concentration for calibration. If a CEST agent is provided, which is additionally labeled by a fluorine marker, the calibration can be performed via 19F-MRI. In this work, a simultaneous turbo-spin-echo imaging sequence is investigated, which allows to acquire 1H-CEST and 19F images at the same time, offering improved time efficiency and precision of the calibration.

10:54 638. Correction for Artifacts Induced by B0 and B1 Field Inhomogeneities in Chemical Exchange Saturation Transfer (CEST) MRI Phillip Zhe Sun1, Christian T. Farrar1, Gregory Sorensen1 1A. A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, USA

Chemical exchange saturation transfer (CEST) imaging provides an indirect detection mechanism that allows quantification of certain labile groups unobservable using conventional MRI. However, CEST contrast is often only a few percent, and therefore, it is important to optimize experimental conditions for reliable and quantitative CEST imaging. In particular, CEST imaging is sensitive to B0 and B1 field, while on the other hand; field inhomogeneities persist despite recent advances in magnet technologies, especially for in vivo imaging at high fields. Consequently, correction algorithms that can compensate for field inhomogeneity-induced measurement errors in CEST imaging might be very useful. In this study, the dependence of CEST contrast on field distribution was solved and a correction algorithm was developed to compensate for field inhomogeneity-induced CEST imaging artifacts. In addition, the proposed algorithm was verified with both numerical simulation and experimental measurements, and showed nearly complete correction of CEST imaging measurement errors caused by moderate field inhomogeneity.

11:06 639. Magnetic Resonance Contrast Based on Relaxation Along a Fictitious Field (RAFF) Timo Liimatainen1, Michael Garwood1, Dennis J. Sorce1, Shalom Michaeli1 1University of Minnesota, Minneapolis, Minnesota, USA

A new contrast based on the frequency swept pulses with sine and cosine amplitude and frequency modulations was developed, referred to as relaxation along a fictitious field (RAFF). Increase of the relaxation rate with increased viscosity was smaller with RAFF than with adiabatic T1ρ and T2ρ. In a fast exchanging system, RAFF relaxation rate was found to be in the same range as adiabatic T2ρ. Relaxation in the dipolar and exchanging systems suggests that the RAFF method appears to slow down dipolar mechanisms as compared to T1ρ and T2ρ, exhibits sensitivity to exchange processes, and produces artifact free relaxation maps.

11:18 640. Activated MR Contrast Agent by a Dual Contrast Technique and Their Application Yoshinori Kato1, Arvind P. Pathak1, Dmitri Artemov1 1Johns Hopkins University School of Medicine, Baltimore, USA

We developed the activated MR contrast agent using the dual contrast technique. The concept behind this strategy is that strong negative signal enhancement due to the T2/T2

* effects of iron oxides dominates the positive T1 contrast generated by a Gd-based contrast agent when these agents are in close proximity, such as within an intact nanocarrier encapsulating GdDTPA/SPIO, and positive T1 contrast becomes evident upon release of Gd-based contrast agent from the carrier once the distance between Gd-based contrast agents and SPIO molecules is beyond the T2/T2

* enhancement range. We corroborated the feasibility of this technique in vitro and in vivo.

11:30 641. Calculation of Susceptibility Maps from Phase Image Data Andreas Schäfer1, Samuel Wharton1, Richard Bowtell1 1University of Nottingham, Nottingham, UK

The phase of gradient echo images carries useful anatomical information resulting from field perturbations due to the variation of susceptibility across tissues. Generating quantitative information from phase images is not straightforward, because of the non-local relationship between field perturbations and susceptibility. Here we show how this problem may be overcome via the calculation of a 3D map of the magnetic susceptibility from phase data. The iterative approach which is proposed takes account of the sphere of Lorentz and external field sources. Its operation is demonstrated via successful application to simulated brain images and phase maps measured from a structured phantom.

11:42 642. High Resolution Human Brain Susceptibility Maps Calculated from 7 Tesla MRI Phase Data Karin Shmueli1, Peter van Gelderen1, Tie-Qiang Li1, Jeff H. Duyn1 1National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, USA

The phase in susceptibility-weighted MRI shows excellent contrast but varies with tissue orientation and is affected beyond areas of altered susceptibility. Magnetic susceptibility is an intrinsic tissue property, closely reflecting tissue composition. Recently-proposed Fourier Transform methods for calculating susceptibilities from phase data were applied to high-resolution 7 Tesla phase images of the human brain (ex- and in-vivo). Some cortical layers were most conspicuous in the susceptibility maps, having consistent contrast independent of their orientation relative to B0, unlike in the phase images where contrast varied with orientation. 3D rather than 2D susceptibility calculations showed most promise for revealing fine-scale brain structure.

11:54 643. Multiple Orientation Acquisition to Invert Dipole Field for Quantitative Susceptibility Mapping Tian Liu1, 2, Pascal Spincemaille2, Ludovic de Rochefort2, Bryan Michael Kressler1, 2, Yi Wang1, 2 1Cornell University, Ithaca, New York, USA; 2Weill-Cornell Medical College, New York, New York, USA

Quantification of susceptibility is practically challenging because the model of this linear system is ill-conditioned. A multiple-orientation measurement is implemented to stabilize this problem. Two reconstruction techniques based on multiple orientation measurement are presented. Both methods provide linearity. Streaking artifacts are eliminated in the reconstruction.

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12:06 644. Multi-Field Behavior of Relaxivity in an Iron-Rich Environment Nilesh R. Ghugre1, 2, Pippa Storey, Cynthia K. Rigsby2, 3, Alexis A. Thompson2, 3, Christine L. Carqueville3, Thomas D. Coates1, John C. Wood1 1Childrens Hospital Los Angeles, Los Angeles, California , USA; 2Northwestern University, Chicago, Illinois, USA; 3Childrens Memorial Hospital, Chicago, Illinois, USA

At 1.5T, relaxivities R2 and R2* can accurately predict hepatic iron concentration in iron overload syndromes. With increasing popularity of 3T scanners, there is need to translate relaxivity-iron relationships to higher field strengths. In this regard, we followed a computational approach by generating realistic liver anatomies and simulating R2 and R2* imaging experiments. We also performed R2 and R2* imaging in the livers of 16 patients at 1.5T and 3T to validate the model. Results demonstrated that R2* scaled linearly with field strength while R2 had a curvilinear relationship. A model-based approach will eliminate the need to recalibrate in patients for changes in sequence type, sequence parameters and imaging conditions.

12:18 645. Role of Anatomic Liver Compartments in Relaxivity-Iron Relationships Nilesh R. Ghugre1, 2, Ignacio Gonzalez1, Ellen Butensky2, Roland Fischer2, 3, Roger Williams2, Paul Harmatz2, Thomas D. Coates1, John C. Wood1 1Childrens Hospital Los Angeles, Los Angeles, California , USA; 2Childrens Hospital and Research Center at Oakland, Oakland, California , USA; 3University Clinic Hamburg-Eppendorf, Hamburg, Germany

R2(1/T2) calibration curve has been established for predicting hepatic iron concentration(HIC) with clinical accuracy. However, there is indication that this relationship is affected by nature of iron overload(transfusion-dependent, hereditary) as well as by type of chelation therapy(subcutaneous, oral). Differences can be attributed to altered iron distribution within two liver compartments viz. hepatocyte and sinusoid. We characterized the relative iron loading in the two compartments(43 patients) and employed a computational approach to systematically evaluate their relative effects on R2. For low HIC, R2 dropped by 15% due to static refocusing while at higher HIC, effects were less apparent. A model-based approach will eliminate the need to recalibrate in patients for changes in therapy and syndrome-type.

Fat-Water Imaging Room 718 B 10:30-12:30 Chairs: W. Thomas Dixon and Charles A. McKenzie

10:30 646. Phase Contrast MRA with Simultaneous Fat-Water Separation Kevin Michael Johnson1, Alexey Samsonov1, Oliver Wieben1 1University of Wisconsin - Madison, Madison, Wisconsin, USA

We present a novel approach capable of performing phase contrast (PC) imaging with fat/water separation in order to minimize image degradations from fat signal. The technique is demonstrated with a modified undersampled 3D radial sequence For non-contrast enhanced abdominal MRA and offers an alternative for patients excluded from CE-MRA because of risk for NSF. In volunteers, PC images show superior visualization of 2nd and 3rd order branches of the renal arteries as compared to clinically used contrast enhanced exam.

10:42 647. Generalized k-Space Decomposition for Non-Cartesian Water/Fat Imaging Ethan K. Brodsky1, 2, James H. Holmes1, Huanzhou Yu2, Scott B. Reeder1 1University of Wisconsin - Madison, Madison, Wisconsin, USA; 2GE Healthcare, Menlo Park, California , USA

Combination of chemical shift based water/fat separation methods with non-Cartesian acquisitions has been very limited due to the blurring and artifacts caused by chemical shift. While the bulk shift of fat associated with chemical shift artifacts in spin-warp imaging is well-understood and clinically acceptable, the phase roll accumulated by off-resonant spins in non-Cartesian sequences is far more destructive to image quality. IDEAL is a multipoint chemical-shift-based water/fat decomposition technique. Performing IDEAL in k-space allows off-resonant fat signal to be rephased, eliminating distortion and enabling imaging techniques with long readouts, such as spirals or low-bandwidth PR imaging, which were previously not clinically useful without fat suppression.

10:54 648. Bipolar Multi-Echo Water-Fat Separation: Phase Correction Using Parallel Imaging Huanzhou Yu1, Charles A. McKenzie2, Ann Shimakawa1, Scott B. Reeder3, Jean H. Brittain4 1GE Healthcare, Menlo Park, California , USA; 2University of Western Ontario, London, Canada; 3University of Wisconsin, Madison, Wisconsin, USA; 4GE Healthcare, Madison, Wisconsin, USA

Three-point water-fat separation techniques have seen a recent increase in clinical use. To improve scan efficiency, recent implementations employ a “bipolar” multi-echo approach, where all echoes are collected in one sequence repetition with alternating gradient polarities. However, the echoes collected with opposite gradient polarities are associated with different phase errors, disrupting the inter-echo phase consistency that is critical for water-fat separation. In this work, we introduce a novel method to correct for the phase error by utilizing parallel imaging reconstruction. A nonlinear phase error can be removed from the bipolar multi-echo data and thus uniform water-fat separation can be achieved.

11:06 649. Fat/Water Separation Using a Concentric Rings Trajectory Hochong H. Wu1, Jin Hyung Lee1, Dwight G. Nishimura1 1Stanford University, Stanford, California , USA

In this work, we present a time-efficient fat/water separation method based on the concentric rings k-space trajectory. Similar to multi-echo acquisitions, rings in the center of k-space are sampled through multiple revolutions to characterize fat/water phase evolution differences at multiple time points. By taking advantage of the unique circularly-symmetric sampling nature of rings, we can extract fat/water phase information at intermediate time points in addition to the number of actual revolutions. Experimental results show that fat/water images can be obtained from appropriate processing of this time-efficient acquisition.

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11:18 650. IDEAL with Turbo-PROP Donglai Huo1, Zhiqiang Li2, Eric Aboussouan1, John P. Karis3, James G. Pipe1 1Barrow Neurological Institute, Phoenix, Arizona , USA; 2GE Healthcare, Waukesha, Wisconsin, USA; 3Southwest Neuro-Imaging, Phoenix, Arizona , USA

Turbo-PROP was developed to provide wider blades for diffusion-weighted and T1-weighted imaging. We propose to reconstruct separate images from different echoes in Turbo-PROP. These images can be synthesized to get a final high-quality image, and at the same time can be used to separate the water and fat signals based on the phase difference with the IDEAL algorithm. Compared with the regular FSE IDEAL approaches, our method can significantly reduce the scan time, and provide the possibility of reliable motion correction (by PROPELLER).

11:30 651. Multi-Echo Tricks Acquisition (META): A High Spatio-Temporal Resolution Multi-Point Dixon Sequence for Dynamic Contrast Enhanced MRI Manojkumar Saranathan1, Dan Rettmann1, Ersin Bayram2, Ramesh Venkatesan3, Anthony T. Vu2, Zachary Slavens2, Naoki Takahashi4, Christine Lee4, Akira Kawashima4, James Glockner4 1Global Applied Science Lab, GE Healthcare, Rochester, Minnesota, USA; 2GE Healthcare, Waukesha, Wisconsin, USA; 3GE Healthcare, Bangalore, India; 4Mayo Clinic, Rochester, Minnesota, USA

Dynamic contrast enhanced MRI (DCEMRI) is widely used in clinical abdominal and pelvic MRI for tissue characterization and visualization of focal lesions. The technique affords adequate spatial resolution but temporal resolution is often insufficient for visualizing hypervascular tumors such as neuro-endocrine metastases and hepato-cellular carcinoma (HCC). Optimal timing of contrast arrival in the organ of interest is critical in capturing “arterial” phases. Furthermore, traditional fat suppression methods perform suboptimally at 3T due to Bo and B1 inhomogeneities. We report a new DCEMRI technique called META (Multi-Echo Tricks Acquisition) that combines a multi-echo TRICKS scan with a two-point Dixon fat-water reconstruction algorithm to generate fat-only and water-only images at very high spatio-temporal resolution.

11:42 652. IDEAL Water-Fat Decomposition with Multipeak Fat Spectrum Modeling Huanzhou Yu1, Ann Shimakawa1, Charles A. McKenzie2, Jean H. Brittain3, Scott B. Reeder4 1GE Healthcare, Menlo Park, California , USA; 2University of Western Ontario, London, Canada; 3GE Healthcare, Madison, Wisconsin, USA; 4University of Wisconsin, Madison, Wisconsin, USA

Previous multi-point water-fat separation methods used a simple model that assumes both water and fat have a single resonant frequency. However, fat spectrum has a number of side-peaks, typically resulting in incomplete separation of water and fat. In this work, a more accurate multipeak model of fat is integrated in the IDEAL water-fat separation technique. A spectrum self-calibration algorithm is developed to estimate the relative amplitudes of three primary fat peaks directly from the 3-pt data, thereby reducing the method’s sensitivity to potential spectrum variation. The improvement in water-fat separation with multipeak-IDEAL is demonstrated in a variety of in-vivo applications.

11:54 653. Hierarchical IDEAL – Robust Water-Fat Separation at High Field by Multiresolution Field Map Estimation Jeffrey Tsao1, Yun Jiang1 1Novartis Institutes for BioMedical Research, Cambridge, Massachusetts, USA

A hierarchical approach to field-map estimation and a new least-squares calculation technique are proposed for robust water-fat separation at high field using the IDEAL acquisition of 3 images at equally spaced but asymmetric echo times.

12:06 654. Noise Considerations in Water-Fat Separation with Bipolar Multi-Echo Sequences Wenmiao Lu1, Huanzhou Yu2, Ann Shimakawa2, Marcus Alley1, Scott Reeder3, Brian Hargreaves1 1Stanford University, Stanford, California , USA; 22Global Applied Science Laboratory, GE Healthcare, Menlo Park, California , USA; 3University of Wisconsin-Madison, Madison, Wisconsin, USA

Bipolar multi-echo sequences provide an efficient means to acquire multiple echoes in a single repetition for water-fat separation. One major problem is that the chemical-shift-induced misregistration between water and fat exists in opposite readout directions between even and odd echoes. Separating water/fat signals in k-space eliminates the chemical-shift induced misregistration. However, the k-space separation results in different noise amplification for different k-space locations. We characterize the colored noise present in separated water/fat images with a noise amplification factor, and demonstrate the utility of the noise amplification factor in choosing imaging parameters or regularization parameters in the case of ill-conditioned separation.

12:18 655. Linear Phase Error Correction for Improved Water and Fat Separation in the Dual-Echo Dixon Techniques Jingfei Ma1, Zachary Slavens2, Wei Sun2, Ersin Bayram2, Lloyd Estowski2, Ken-Pin Hwang3, James Akao2, Anthony T. Vu2 1University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA; 2GE Healthcare, Waukesha, Wisconsin, USA; 3GE Healthcare, Houston, Texas, USA

The presence of unusually large linear phase errors may pose challenges to phase correction that is needed for Dixon water and fat separation. In this work, we propose a two-step process that first corrects linear phase errors with a modified Ahn-Cho algorithm and then applies a previously-developed region growing algorithm to correct the residual nonlinear components. We demonstrate that successive application of the two-step process provides a “1-2 punch” to the phase errors and can overcome water and fat separation failures occasionally encountered when the region growing based algorithm alone is applied to the dual-echo Dixon processing.

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Metabolic & Functional Assessment of Cancer Treatment: Animal Models Room 714 A/B 10:30-12:30 Chairs: Gregory S. Karczmar and Simon P. Robinson

10:30 656. Assessment of Radiation Mediated Gene Therapy Via Multi-Modality Imaging Chad Roland Haney1, Adrian D. Parasca1, Rebecca Bell1, Marta Zamora1, Xiaobing Fan1, Gregory S. Karczmar1, Helena J. Mauceri1, Ralph R. Weichselbaum1, Howard J. Halpern1, Charles A. Pelizzari1 1University of Chicago, Chicago, Illinois, USA

Imaging techniques are under development which, are intended to facilitate early analysis of spatial patterns of tumor response to combined radiation and antivascular gene therapy. Changes of vascular permeability and perfusion maps using Dynamic-contrast-enhanced MRI, and tissue oxygenation measurements using electron paramagnetic resonance imaging were registered to characterize a “signature” for response. This is the first report of quantitative, absolute oxygen measurements being correlated with tissue perfusion, in vivo and non-invasively. Radiation mediated antivascular gene therapy appears to significantly improve tissue oxygenation by normalizing perfusion, i.e., decreasing uptake and increasing washout of contrast agent.

10:42 657. In Vivo 19F MRS Detection of Carboxypeptidase G2 Activity < Yann Jamin1, Lynette Smyth2, Simon P. Robinson1, Thomas R. Eykyn1, Caroline J. Springer2, Martin O. Leach1, Geoffrey S. Payne1 1Institute of Cancer research and Royal Marsden NHS trust, Sutton, UK; 2Institute of Cancer Research, Sutton, UK

Carboxypeptidase G2 is used in Gene Directed Enzyme Prodrug Therapy, a promising gene therapy strategy for cancer treatment to activate non toxic prodrugs into cytotoxic DNA alkylating agents. We report in vivo non-invasive 19F MRS detection of Carboxypeptidase G2 activity following intravenous injection of 3,5-Difluorobenzoylglutamic acid (3,5-DFBGlu) in mice bearing xenografts derived from human colon adenocarcinoma WiDr cells stably expressing CPG2. The high signal-to-noise ratio afforded by the two equivalent 19F nuclei of 3,5-DFBGlu allows the 19F 3D spectroscopic imaging to image the location of CPG2 activity.

10:54 658. Non-Invasive Detection of Tumor Cell Death - Comparison Between FDG and Hyperpolarized 13C-Labelled Pyruvate Timothy Howard Witney1, 2, Sam E. Day3, Mikko I. Kettunen1, 2, Andre A. Neves1, 2, Ferdia A. Gallagher1, 2, Jan H. Ardenkjaer-Larsen4, Kevin M. Brindle1, 2 1University of Cambridge, Cambridge, UK; 2CRUK Cambridge Research Institute, Cambridge, UK; 3National Institutes of Health, Bethesda, USA; 4GE Healthcare, Amersham, UK

The aim of this study was to monitor tumor response to treatment, comparing uptake and metabolism of hyperpolarized 13C-labelled pyruvate to the uptake of [14C]FDG in EL4 cells. Induction of cell death by etoposide lead to a progressive decrease in the lactate dehydrogenase-catalyzed pyruvate/lactate flux. This coincided with a loss of the cellular NAD(H) pool and a marked increase in the number of apoptotic cell. A similar decrease in [14C]FDG uptake was observed following treatment. The results suggest that 13C-labelled pyruvate may be useful for detecting early responses of tumours to chemotherapy.

11:06 659. Phosphorus MRS Effectively Monitors Lentiviral-Mediated Gene Therapeutic Silencing of Choline Kinase in a Human Breast Cancer Xenograft Kristine Glunde1, Balaji Krishnamachary1, Flonne Wildes1, Venu Raman1, Zaver M. Bhujwalla1 1The Johns Hopkins University School of Medicine, Baltimore, USA

Choline kinase (Chk) overexpression contributes to the elevated phosphocholine (PC) and phosphomonoester (PME) levels detected in breast cancers. Chk is currently being explored as target for anticancer therapy. Here we have used in vivo single-voxel 31P MRS to monitor and evaluate an optimal treatment regimen for systemic delivery of lentiviral particles that silence Chk by Chk-specific short-hairpin RNA. Bi-weekly intravenous administration of these lentiviral particles significantly decreased tumor growth of breast cancer xenografts. Decreased tumoral PC and PME levels demonstrated a successful functional therapeutic response, as monitored noninvasively by 31P MRS in vivo.

11:18 660. Tracking Chemotherapy-Induced Changes in Tumor Antigen Expression in a Pre-Clinical Breast Cancer Model Zdravka Medarova1, Leonid Rashkovetsky1, Pamela Pantazopoulos1, Anna Moore1 1Massachusetts General Hospital, Charlestown, Massachusetts, USA

A key goal of cancer research is to monitor and predict the response to treatment. Considering the variability of the response, this has to be accomplished on a patient-by-patient basis. With this in mind, we applied magnetic resonance imaging to monitor the expression of a tumor-specific antigen (uMUC-1), found on over 90% of breast cancers and predictive of chemotherapeutic response. As a contrast agent, we employed an imaging probe (MN-EPPT) targeting uMUC-1. MN-EPPT consists of superparamagnetic iron oxide nanoparticles (MN) for MR imaging, modified with Cy5.5 dye (for fluorescence optical imaging), and conjugated to peptides (EPPT), specifically recognizing uMUC-1

11:30 661. Vessel Size Index MRI with Viable Tumor Analysis for Monitoring Anti-Angiogenic Therapeutics Sharon E. Ungersma1, Sharon Fong Yee1, Glenn Pacheco1, Germaine Fuh1, Joan M. Greve1, Franklin V. Peale Jr. 1, Sarajane Ross1, Richard A. D. Carano1 1Genentech, Inc., South San Francisco, California , USA

Vessel size index (VSI) MRI determines fractional blood volume and mean vessel size on a voxel-by-voxel basis using changes in T2 and T2* caused by the introduction of an iron oxide contrast agent. In this study, we use VSI MRI to examine the effect of G6-31, an anti-VEGF-A monoclonal antibody. To account for tumor heterogeneity, we restrict the VSI parameter analysis to the viable tumor tissue as determined with multispectral clustering. The viable tissue technique requires no additional scans beyond those used for VSI MRI and can improve accuracy of tumor parameter measurement by eliminating necrotic regions from the analysis.

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11:42 662. Time-Resolved MRA Assessment of Pulmonary Toxicity in a Rabbit Model of Stereotactic Lung Radiation Therapy: Preliminary Results on the Efficacy of a Radioprotector Jaime Mata1, Ke Sheng1, Paul Read1, Klaus Hagspiel1, Kai Ruppert2, Anthony Soltis1, James Brookeman1, John Mugler III1 1University of Virginia, Charlottesville, USA; 2University of Pennsylvania, Philadelphia, USA

Radiation-induced pulmonary symptoms occur in approximately 20% of patients who receive radiation treatment for cancer of the lung or breast. Presently, there is no clinical test available to predict toxicity or to assess the extent of radiation-induced lung injury early after treatment. However, early detection might allow for preventative therapy to reduce toxicity and, if early lung damage could be detected during radiotherapy, this would allow a change in the plan prior to extensive damage. In this work we report the use of time-resolved MRA to assess the efficacy of a radioprotector in limiting radiation toxicity in a rabbit model of stereotactic-radiation pulmonary injury.

11:54 663. DCE-MRI Provides Evidence for Vascular Effects of AMG 386, a First-In-Class Anti-Angiogenic Peptibody That Specifically Inhibits Interaction of Angiopoietins-1 and -2 with Tie-2 Yuying C. Hwang1, Ed Ashton2, Lee Rosen3, Roy Herbst4, Jeffrey Silverman5, Ngocdiep Le1, Erik Rasmussen1, Jon Oliner1, Juan Leal6, Robert Radinsky1, Ji-Rong Sun1, Jeff Evelhoch1, Ed Jackson4 1Amgen Inc., Thousand Oaks, California , USA; 2VirtualScopics Inc., Rochester, New York, USA; 3Premiere Oncology, Santa Monica, California , USA; 4The University of Texas M.D. Anderson Cancer Center, Houston, Texas, USA; 5Landmark Imaging, Los Angeles, California , USA; 6University of Minnesota, Twin Cities, Minnesota, USA

AMG 386 is a peptide-fc fusion protein (peptibody) that specifically inhibits the interaction of angiopoietins-1 and -2 (Ang1/2) with Tie-2 receptor. We performed DCE-MRI in Colo205 xenografts and in the first in human (FIH) clinical trial to study the effect of AMG 386 on tumor vasculature. Both pre-clinical and clinical DCE-MRI results demonstrate a significant vascular effect of this first-in-class anti-angiogenic investigational drug that provides highly potent and selective inhibition of angiopoietins, even though the vascular effects are not as dramatic as for VEGF-targeted molecules.

12:06 664. Using BOLD MRI with Carbogen to Evaluate Tumour Response to Antiangiogenic Therapy Simon Walker-Samuel1, Lesley D. McPhail1, Anderson J. Ryan2, Simon P. Robinson1 1Institute of Cancer Research, Sutton, UK; 2AstraZeneca, Macclesfield, UK

Biomarkers derived from blood oxygen level dependent (BOLD) MRI with carbogen and diffusion MRI were used to assess the acute effects of an antiangiogenic agent (vandetanib, AstraZeneca) in murine PC3 xenografts. Following therapy, a significant decrease was observed in both median baseline (pre-carbogen) R2* and median ÄR2* (the change in R2* induced by carbogen), suggesting improved blood flow and a decrease in tumour deoxyhaemoglobin. No significant change in the apparent diffusion coefficient was observed. These results are consistent with the proposed hypothesis of vascular normalisation, in which the efficacy of tumour vasculature is temporarily improved following antiangiogenic therapy.

12:18 665. Diffusion Weighted Imaging as Predictor of Therapy Response in Animal Model of Ewing-Sarcoma Wilfried Reichardt1, Udo Kontny1, Markus Uhl1, Dominik von Elverfeldt1 1University of Freiburg, Freiburg, Germany

Diffusion weighted imaging (DWI) has proved to be a valuable tool in monitoring the effect of chemotherapy in clinical as well as in preclinical studies. Especially early assessment of treatment induced changes using DWI seems to be a promising tool in the evaluation of novel therapies. High dose chemotherapy in Ewing’s sarcoma has been demonstrated to be associated with higher cure rates than conventional chemotherapy in relapsed patients. The goal of this Study was to evaluate diffusion-weighted magnetic resonance imaging for monitoring dose dependent tumour response in mouse-xenograft model of Ewing’s Sarcoma after administration of Treosulfan in different dosages

CLINICAL CATEGORICAL COURSE Body MRI by the Experts IV: Female Pelvis Room 716 A/B 10:30 - 12:30 Chair: Qun Chen, Clare Tempany, and Bernard E. Van Beers

Educational Objectives: Upon completion of this course, participants should be able to:

• Describe the impact of functional, quantitative, and molecular MR in abdominal imaging; • Apply new body MR techniques in their practice; • Use multiparametric MRI for improved diagnosis of abdominal diseases; • Describe indications of functional and quantitative MRI in the assessment of liver, pancreas, bowel, and kidney diseases; • Design new female pelvic and prostate protocols, introducing these methods and compare them to more conventional approachs; and • Appraise the indications for anatomical and functional imaging of the breasts and the lungs.

10:30 Female Pelvis MR Update Kaori Tagoshi 11:00 MR Cervical Cancer Nandita De Souza 11:30 MR Imaging of Fibroids, Treatment, and Monitoring Treatment Effects

Gina Hesley 12:00 MR-Guided Focused Ultrasound for Fibroids

Fiona Fennessy

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Immature Brain Room 701 A 10:30-12:30 Chairs: Patricia Ellen Grant and Ed X. Wu

10:30 666. In Utero MRI Study of Fetal Baboon Brains at 3T Feng Liu1, 2, Marianne Garland1, Yunsuo Duan1, 2, Raymond Stark1, Dongrong Xu1, 2, Zhengchao Dong1, 2, Ravi Bansal1, 2, Bradley Peterson1, 2, Alayar Kangarlu1, 2 1Columbia University Medical Center, New York, New York, USA; 2New York State Psychiatric Institute, New York, New York, USA

MRI techniques provide a noninvasive tool to study the developing primate brain. We devised a protocol to serially scan pregnant baboons at 3 Tesla for up to 3 hours per session. Seven baboons were scanned beginning as early as 56 days of gestation, to as late as 185 days. Successful scanning of the fetal baboon required careful animal preparation and anesthesia in addition to optimization of the scanning protocol. This protocol will help to advance the use of nonhuman primate models to study fetal brain development longitudinally.

10:42 667. Diffusion Spectrum Imaging (DSI) Tractography of Neonatal Cat Brains Emi Takahashi1, Guangping Dai1, Ruopeng Wang1, Van J. Wedeen1 1Harvard Medical School, Massachusetts General Hospital, Charlestown, Massachusetts, USA

By diffusion tractography using diffusion spectrum imaging (DSI), we demonstrate and validate the feasibilities of the diffusion tractography in neonatal cat brains, which promises future applications of the technique to pediatric disorders in humans. We found dramatic structural changes of major white matter tracts during postnatal development. Particularly, the cingulum bundle increased its length and complexity a lot in the first month of the postnatal development. We believe that our approach here is fundamental to understand the normal and abnormal formation of cortical gyri related to underlying the white matter structures.

10:54 668. Framework for Comparing Mutant Mice Against a DTI-Based Normative Atlas of Mouse Brain Development Jinzhong Yang1, Sajjad Baloch1, Hao Huang1, Sarah Clark1, Paul Yarowsky1, Susumu Mori1, Christos Davatzikos1, Ragini Verma, 1, UPenn, Philadelphia, Pennsylvania, USA

In this work we provide a framework for comparing differences between a knockout strain and a normative atlas of the developing mouse brain. We have used Diffusion Tensor Imaging (DTI) in a novel computational neuroanatomy approach to quantify postnatal developmental patterns of C57BL/6J mouse brain and have created a growth and maturation profile of the C57BL/6J mouse, which is used as a normative brain for several knock-out strains. This lays the foundation for a normative atlas for a developing brain against which brain anomalies can be quantified. In this work we provide a framework that facilitates such a comparison of neuropathology against the normative baseline. We show the application of this normative atlas in determining growth and maturation abnormalities in a hybrid mouse that has been genetically altered. The framework is general and can be applied to determining changes in mice that have been mutated, at any stage of their development.

11:06 669. Directional Diffusion Kurtosis Analysis of Rat Brain Maturation Matthew Man Hin Cheung1, 2, Edward Sai Kam Hui1, Ed X. Wu1 1The University of Hong Kong, Pokfulam, Hong Kong

Diffusion Kurtosis Imaging is capable of quantifying the biological tissue complexity. In this experiment, DKI is applied to study the rat brain maturation. The directional kurtoses were found to be highly sensitive to the developmental changes. The restriction in radial direction was found to increase dramatically, probably due to the myelination and other intrinsic axonal factors. The diffusion characteristics and the structural information provided are essential in better understanding of developmental and aging physiology.

11:18 670. White Matter Alteration in Brain Hemisphere Contralateral to Ligation in Neonatal Rat Model of Hypoxic-Ischemic Injury Ho-fai Lau1, 2, Jian Yang1, Pek-Lan Khong1, Ed X. Wu1 1The University of Hong Kong, Pokfulam, Hong Kong

Purpose: This study aim to investigate the hypoxic-ischemic (HI) injury in brain hemisphere contralateral to ligation in neonatal rats with DTI. Rats with unilateral left carotid artery ligation were exposed to hypoxic environment for 1 hour (n=9) and 2 hours (n=9) to induce mild and severe HI injuries, respectively. They, together with intact controls (n=11) were longitudinally examined for changes in FA, axial and radial diffusivities. FA decrease and axial diffusivity increase were observed during the acute and subacute stage in the hemispheres contralateral to the ligation when compared to controls. The findings indicated that WM on seemingly normal contralateral hemisphere was indeed adversely affected, which may impact the long-term brain development after mild or severe HI injury.

11:30 671. Correlation of Neuroinflammatory Molecules Quantified from CSF with Fractional Anisotropy in the Neonatal Meningitis Rakesh K. Gupta1, Richa Trivedi1, Gyanendra K. Malik2, Abhishek Yadav1, Kashi N. Prasad1, Ram KS Rathore3 1Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India; 2Chhatrapati Shahuji Maharaj Medical University, Lucknow, India; 3Indian Institute of Technology, Kanpur, India

Diffusion tensor imaging (DTI) was performed on 15 neonates with bacterial meningitis and 10 age/ sex matched controls. Enzyme linked immunosorbent assay was used to quantify neuroinflammatory molecules (sICAM, TNF-á and IL-1â cytokines) in CSF collected on lumber puncture of meningitic neonates. Fractional anisotropy (FA) and mean diffusivity (MD) values were measured by placing region of interests on leptomeningeal corticosubcortical white matter (LCSWM) regions in both patients and controls. Significantly increased FA with no significant change in MD values was observed in patients compared to controls. A significant positive correlation was observed between neuroinflammatory molecules quantified from CSF of patients and FA values collected from LCSWM. Our results suggest that the high FA in LCSWM in neonates with bacterial meningitis reflects the extant of inflammatory response.

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11:42 672. Development of Fetus Brain Atlas from Multi-Axial MR Acquisitions Nicolas Guizard1, 2, Claude Lepage2, Vladimir Fonov2, Helene Hakyemez1, Alan Evans2, Catherine Limperopoulos1 1MCH, Montreal, Canada; 2BIC, Montreal, Canada

Innovative applications of advanced MRI techniques to the high-risk fetus are increasingly providing a powerful tool for the in vivo study of brain development. The ability to reliably acquire 3-D volumetric sequences and to delineate volumetric brain growth in the non-sedated fetus is challenging, but essential for the accurate assessment of the progression of normal and abnormal fetal brain growth in the second and third trimester. The development of a fetal brain atlas would enable a comprehensive and quantitative approach for the study of healthy and high-risk fetal brain growth, and ultimately improve the sensitivity, specificity and prognostic utility of fetal MRI.

11:54 673. DTI Study of Effects of Glucocorticoids on White Matter Development L Tugan Muftuler1, Orhan Nalcioglu1, Curt Sandman1, Elysia Davis1 1University of California, Irvine, California , USA

The goal of this study was to investigate changes in cerebral white matter morphology among children with prenatal exposure to glucocorticoids. Pregnant woman at risk for premature delivery are routinely administered GCs to promote lung development and survival among premature infants. However, findings from human and animal studies show that exposure to GCs has influence on emotion and stress regulation, cognitive functioning and brain morphology. We have found changes in FA values in white matter in the basal ganglia. The area involved includes a region where AC fibers intermix with striato-pallido and internal pallido subcortical projection fibers.

12:06 674. Fetal Exposure to Bisphenol a Alters Mitochondrial Function Nicolas Kunz1, Emily J. Camm2, Emmanuel Somm2, Ingrid Kolher1, Stéphane V. Sizonenko2, Michel L. Aubert2, Petra S. Huppi2, Rolf Gruetter1, 3 1Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; 2University of Geneva, Geneva, Switzerland; 3University of Lausanne and Geneva, Switzerland

Bisphenol A (BPA; 4,4’-isopropylidenediphenol) has been implicated as an endocrine-disrupting chemical due to its ability to mimic the action of endogenous steroidal hormones resulting in accelerated growth and puberty, reproductive malformations and behavioral modifications. The aim of the project was to evaluate the effect of BPA exposure in the developing rat brain using proton spectroscopy (1H-MRS) at 9.4 Tesla at P20. A significant increase of the Glu/Asp ratio in the hippocampus was detected, which was likely due altered malate-aspartate shuttle activity implicating impaired mitochondrial function.

12:18 675. Effect of Fetal-Hypoxemia on Neurochemical Profile of Neonate Guinea Pigs During Development Wen-Tung Wang1, Sang-Pil Lee1, Yafeng Dong1, Carl P. Weiner1, In-Young Choi1 1University of Kansas Medical Center, Kansas City, Kansas, USA

Hypoxia is one of the pregnancy complications that lead to fetal neuro-developmental damage. In this study, 1H MRS was employed to determine whether maternal hypoxia alters neurochemical levels in the neonatal guinea pigs as an adaptive response to the reduced oxygenation before birth. The results show that, while changes in metabolite concentrations happened on postnatal day 0 (P0) in all three regions (hippocampus, striatum, and cerebral cortex), most significant changes happened in the striatum. Further the decrease in Glu on P0 may be associated with delayed or damaged neuronal development due to hypoxia during gestation.

New Frontiers in Spin Detection Room 701 B 10:30-12:30 Chairs: Steven M. Conolly and Mary McDougall

10:30 676. First Microtesla MRI of the Human Brain Vadim S. Zotev1, Andrei N. Matlashov1, Petr L. Volegov1, Igor M. Savukov1, Michelle A. Espy1, John C. Mosher1, John J. Gomez1, Robert H. Kraus, Jr. 1 1Los Alamos National Laboratory, Los Alamos, New Mexico, USA

Magnetic resonance imaging at ultra-low fields (ULF MRI) uses SQUIDs (superconducting quantum interference devices) to measure spin precession at a microtesla-range magnetic field after sample magnetization is enhanced by a stronger pre-polarizing field. Here, the first ULF images of the human head acquired at 46 microtesla measurement field with pre-polarization at 30 mT are reported. The imaging was performed with 3 mm x 3 mm x 6 mm resolution using the 7-channel SQUID system designed for both ULF MRI and magnetoencephalography (MEG). This result demonstrates feasibility and potential of human brain imaging at microtesla magnetic fields.

10:42 677. Ultra-Sensitive Micron-Cantilever Detection for MRI Modhurin Banerjee Snyder1, Krishna Kurpad1, Charles Paulson1, Daniel van der Weide1, Thomas M. Grist1 1University of Wisconsin,Madison, Madison, USA

A new mixing and filtering technique for magnetic signal detection based on the principles of magnetic force microscopy (MFM) is described. MFM adapts sensitivity of MFM to force-detect RF-magnetic signals at distances necessary for in-vivo imaging. Instead of using a coil antenna with resonant LC network, an untuned coil antenna is coupled magnetically to an ultra-sensitive, MFM cantilever with an integral coil. Forces on the cantilever tip from the untuned coil antenna cause deflection of the cantilever, whose instantaneous position is measured by reflection of a laser onto a detector. The resonant cantilever acts as an electromechanical filter and sensitive signal transducer. The system is frequency agile, allowing broadband operation and though thermal-noise limited, the system provides several potential advantages over conventional NMR detector coils; the parameters affecting the sensitivity of the antenna and their effects on signal-to-noise ratio are calculated.

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10:54 678. Active Feedback-Enhanced MRI: Hardware Development and Applicatiosn to Early Tumor Detection Dennis W. Hwang1, Susie Y. Huang2, Lian-Pin Hwang3, Yung-Ya Lin1 1UCLA, Los Angeles, California , USA; 2Harvard Medical School, Boston, Massachusetts, USA; 3National Taiwan University, Taipei, Taiwan

A conceptually new approach to enhance MRI contrast by manipulating the intrinsic spin dynamics in the presence of nonlinear feedback interactions has recently been demonstrated. In this work, we fabricate an active RF feedback device to amplify and control the radiation damping feedback field. To validate the efficacy of active RF feedback, tumor detection and characterization in in vivo mice injected with human lung cancers was investigated. It is shown that active RF feedback circuit enables improved differentiation of neighboring normal and abnormal tissues at low fields using conventional probes/receiver coils.

11:06 679. NMR Experiments Using No RF Coil: RF-Coilless NMR Xiaoliang Zhang1, 2 1University of Minnesota, Minneapolis, USA; 2University of California San Francisco, San Francisco, USA

In this work, we investigate an unusual NMR experiment method which uses no RF coils. The method is based on the dielectric resonance (or sample self-resonance) property of a NMR sample with finite boundaries. The NMR images and proton spectra of a cylindrical water sample acquired on a 7T scanner are presented. NMR with no RF coil may provide a more sensitive and simplified way to perform NMR because an entire subsystem in the NMR signal receiving chain, RF coil, is eliminated.

11:18 680. A Magnetic Field Monitoring Add-On Toolkit Based on Transmit-Receive NMR Probes Pekka Sipilä1, 2, Silke Lechner1, 2, Dirk Lange1, Sebastian Greding1, Gerhard Wachutka2, Florian Wiesinger1 1GE Global Research, Munich, Germany; 2Technical University of Munich, Munich, Germany

Magnetic Field Monitoring (MFM) system based on NMR probes promises an effective method to correct B0 and gradient imperfections in MRI. This is of great interest, because the practical applicability of several advanced pulse sequences is hindered due to these non-idealities. However, receive-only NMR probes are relatively cumbersome to use, as the probes have to be aligned with the excitation plane of the imaged object itself. In this paper, a more practicable MFM setup is described in form of transmit-receive NMR probes. Having a second exciter channel available, MFM monitoring can be flexibly performed almost independent of the pulse sequence chosen.

11:30 681. Non-Magnetic Cartesian Feedback Transceivers – a New Approach to MR RF Instrumentation David Ian Hoult1, Derek Foreman1, Glen Kolansky1 1National Research Council Institute for Biodiagnostics, Winnipeg, Canada

Primarily for use with transmit/receive high-field phased arrays, the concept of distributing multiple, non-magnetic Cartesian feedback transceivers around the back of the imaging magnet is presented. Close proximity to the array coils ensures minimal cable RF power loss, while the feedback corrects distortion and allows inexpensive, non-magnetic transistor RF power amplifiers to be used. The feedback also ensures that induced currents in coupled coils (transmit and receive) are reduced by a factor of 100, and stable performance has been verified with 2 coupled coils attached to two instruments. Control is via a USB-based link to an external computer.

11:42 682. Realized Wireless Transceiver for MRI Coil Array Juan Wei1, Gary X. Shen1 1The University of HongKong, Hong Kong, People's Republic of China

The link budgets of analog and digital wireless transmission for MR signals have been made. Although analog transmission may be has higher SNR and sensitivity in theory, the digital one is more feasible with better stability and noise immunity. Also with the rapid growth of wireless LAN (WLAN) for the data rates from 2Mbps up to 108Mbps and precipitous drops in prices of WLAN products, an application of digital wireless transmission for MR signals based on 802.11b has been realized.

11:54 683. Single Optical Fiber Transmission for Multi-Channel MRI Using FDM Method Gary X. Shen1, Juan Wei, Jing Yuan, Yong Pang 1The University of Hong Kong, Hong Kong, Hong Kong

A single analog optical link system for multiple channel RF transmission is designed and implemented. All the RF channel signals can be down converted to the different low frequencies using frequency division multiplexing (FDM) method, and combined to a single optical link for transmission. The primary bench tests show that the system has very good dynamic range, linearity and SNR. This design can significantly reduce the system complexity and cut the cost of using multiple independent optical transmit links and optical receivers for multi-channel array MRI applications.

12:06 684. Development of a Multi-Channel Transmit Extension for a Broadband RF-Electronics and Its Evaluation on a 9.4 T Animal Scanner with 8 Transmit Channels Peter Ullmann1, Gerhard Eber2, Thomas Eckert2, Paul Freitag1, Gernot Götzelmann1, Michael Heidenreich1, Ulrich Heinen1, Sven Junge1, Pietro Lendi3, Balz Odermatt3, Hans Post1, Jens Rommel2, Arthur Schwilch3, Willy Uhrig2, Ralf Velten1, Uwe Wark1, Ewald Weber4, Wolfgang Ruhm1 1Bruker BioSpin MRI GmbH, Ettlingen, Germany; 2Bruker BioSpin GmbH, Rheinstetten, Germany; 3Bruker BioSpin AG, Fällanden, Switzerland; 4The University of Queensland, Brisbane, Australia

In this work a multi-channel transmit extension for a broadband RF electronics with the potential of driving large numbers of transmit channels was developed. This novel electronics setup was implemented on a 9.4 T animal scanner with 8 transmit and receive channels and its functionality was successfully verified in experiments of B1-shimming and Parallel Excitation.

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12:18 685. Integration of an All Port Drive TEM Transmission Line Coil with a Digital Transmit/receive Chain Matthew G. Erickson1, Krishna N. Kurpad2, James H. Holmes2, Sean B. Fain 1University of Wisconsin, Madison, Wisconsin, USA; 2U of Wisconsin, Madison, Wisconsin, USA

A TEM transmission line coil with all port drive was reported in the October 2007 issue of MRM. In this work, we describe the integration of this deisign with a state of the art, multi-channel all digital T/R chain. The receiver in the chain is a Mercury Visage direct digital receiver which uses a fold-back Nyquist digitization scheme in conjunction with analog anti-aliasing filters. The transmitter is an experimental prototype based on ultra high speed D/A converters controlled by field programmable gate array (FPGA) chips. Phase, frequency, receiver gain, and transmitter amplitud are all software controlled. The need for quadrature hybrids and/or power dividers is neatly eliminated. The system is portable, and maybe used at any filed strength between 0.2T and 11T with no special modifications.

CLINICAL CATEGORICAL COURSE Areas to Watch: Clinical Developments in Lung Imaging Room 713 A/B 10:30 - 12:30 Chair: Qun Chen, Clare Tempany, and Bernard E. Van Beers

Educational Objectives: Upon completion of this course, participants should be able to:

• Explain what information the latest MRI techniques can provide; • Describe the strengths and weaknesses of using MRI for the evaluation of lung disease and disorders; • Select appropriate sequences for imaging a particular patient; and • Interpret findings from MR images collected using these new MRI techniques.

10:30 Helium-3 MRI: Clinical Applications of Quantitative Measurements of Regional Lung Ventilation Yves Berthezène 11:00 Hyperpolarized Helium MRI of Asthma Mitchell S. Albert 11:30 Time-Resolved Three-Dimensional Contrast-Enhanced Pulmonary Magnetic Resonance

Christian Fink 12:00 Dynamic Perfusion MRI of Lung Cancer

Yoshiharu Ohno

Spectroscopy Quantitation & Methodology Room 715 A/B 10:30-12:30 Chairs: Carolyn Mountford and Peter Vermathen

10:30 686. Astounding Reproducibility of Cerebral Phenylalanine Levels as Determined by 1H-MR Spectroscopy

Roland Kreis1, Karin Zwygart1, Chris Boesch1, Jean-Marc Nuoffer2 1University Bern, Bern, Switzerland; 2Childrens University Hospital, Bern, Switzerland

The reproducibility of metabolite content determined by MRS is usually at best a few percent for the most prominent singlets. When studying low-concentration metabolites, like phenylalanine (Phe), where tissue content can be <100 μmol/kg, better reproducibility is needed. An optimized, targeted MRS method was tested and calibrated at 1.5T in 34 healthy controls and reproducibility established in 20 patients with phenylketonuria (3 independent sessions with 3 spectra each). Intersession variation was found to be only 7 μmol/kg Phe, in agreement with the spectrum-per-spectrum variation of 16 μmol/kg. ANOVA proves individuality of blood/brain Phe ratios – though moderated by further influences.

10:42 687. In Vivo 1H NMR Measurement of Glycine in Human Brain at 7 T at Short Echo Time Giulio Gambarota1, Ralf Mekle1, Lijing Xin1, Martin Hergt2, Wietske Van der Zwaag1, Rolf Gruetter1, 3 1Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland; 2Siemens-CIBM, Lausanne, Switzerland; 3University of Lausanne and University of Geneva, Switzerland

Glycine is an amino acid present in mammalian brain. The non-invasive measurement of glycine in brain is hampered by the fact that its singlet resonance at 3.55 ppm overlaps with the much larger resonances of myo-inositol. To overcome this problem, editing techniques have been used to detect glycine in healthy human brain. In the present study we show that it is possible to detect glycine in human brain in vivo, at a reasonably short TE of 30 ms without editing methods, at 7 T.

10:54 688. Detection of Glutathione in Human Brain in Vivo by Yield-Enhanced Double-Quantum Filtering at 3T Changho Choi1, Nicholas J. Coupland2, Peter Seres2, Paramjit P. Bhardwaj2, Sanjay Kalra2, Philip G. Tibbo2, Agitha Valiakalayil2 1University of Texas Southwestern Medical Center, Dallas, USA; 2University of Alberta, Edmonton, Canada

Yield enhancement of proton NMR double-quantum (DQ) filtering for selective measurement of glutathione (GSH) in human brain at 3.0 T is reported. After the generation and encoding of DQC, selective 180° rotation of the GSH 4.56-ppm resonance was applied to interchange between DQC and ZQC, which was followed by another encoding gradient within the mixing time. These encoded coherences, after conversion to antiphase coherences, were evolved to bring about an enhanced GSH edited multiplet at ~2.95 ppm during the second echo period. A phantom test indicated yield of 55% with respect to 90°-acquisition. The concentration of GSH in the human parietal cortex was estimated as 0.8 mM, with reference to creatine at 8 mM.

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11:06 689. In-Vivo Lactate Detection Using Selective MQ Coherence Spectroscopy: Signal Enhancement Using Spectral-Selective Binomial RF Pulses (SS-SelMQC) Sunitha B. Thakur1, Jadegoud Yaligar1, Jason A. Koutcher1 1Memorial Sloan Kettering Cancer Center, New York, New York, USA

We report a novel modification of the SelMQC sequence using binomial spectral-selective pulses (SS-SelMQC). Frequency selective excitation pulses were employed with suitable phase cycling of a binomial sequence to selectively excite either lactate methyl or methylene resonances. Chemical shift selection was achieved by adjusting the interpulse delay equal to the inverse of twice the difference in the center frequencies of maximum and null excitation bands. In a lipid enriched environment, the modified sequence yielded enhanced lactate signal of 200-300% compared to SelMQC. Non-localized proton spectra and 2D CSI-lactate images were obtained from 30mM lactate/lipid phantoms and in-vivo R3327 prostate tumors.

11:18 690. Validation of Human Brain Vitamin C Concentration Measured Noninvasively Using Short-Echo Time 1H MRS at 7 T Versus MEGA-PRESS Edited Spectra Melissa Terpstra1, Ivan Tkac1 1University of Minnesota, Minneapolis, Minnesota, USA

The purpose of this study was to assess reliability of quantification of Asc concentration using short echo time 1H MR spectroscopy in the human brain at 7 T, which would allow for quantification of the entire neurochemical profile and minimize the influence of T2 relaxation. The 1.2 ± 0.3 µmol/g (mean ± SD) Asc concentration measured using ultra-short TE (6 ms) STEAM was validated by the 1.2 ± 0.2 µmol/g concentration measured using MEGA-PRESS editing for Asc (TE = 112 ms) in identical occipital cortex VOI of 8 human subjects.

11:30 691. ProFit-Based Quantitation of Cerebral Metabolites Using 2D L-COSY at 3T Enrique Frias-Martinez1, Nagarajan Rajakumar1, X. Liu1, A. Singhal1, S. Banakar1, Scott Lipnick1, Gaurav Verma1, S. Ramadan1, Anand Kumar1, Michael Albert Thomas1 1UCLA, Los Angeles, California , USA

Recently, quantitation of maximum-echo sampled 2D J-resolved spectra using ProFit has been evaluated in human brain and prostate in vivo, and identification of more than ten metabolites has been demonstrated. Due to the retention of both chemical shift and J-coupling in both dimensions, localized 2D shift correlated spectroscopy (L-COSY) offers improved spectral dispersion along the 2nd dimension than 2D JPRESS. A goal of the proposed work was to modify ProFit for processing the 2D L-COSY spectra recorded in healthy human brain and a brain phantom containing several metabolites using a prior knowledge based basis set of more than twenty metabolites.

11:42 692. Normal Brain Metabolic Distributions and Age-Dependent Changes Andrew A. Maudsley1, Claudia Domenig1, Ammar Darkazanli1, Varanavasi Govindaraju1, Yuhua Gu2, Larry Hall2, Colin Studholme3 1University of Miami, Miami, Florida, USA; 2University of South Florida, Tampa, Florida, USA; 3University of California San Francisco, San Francisco, California , USA

The distributions of brain metabolites and their change as a function of age have been measured in a group of normal subjects using a high-spatial resolution MRSI protocol. Results demonstrate considerable spatial heterogeneity as well as age-dependent changes, with no differences with gender.

11:54 693. Probing Dynamics of Human Brain Metabolites with 1H MRS by T1ρ and T2ρ Adiabatic Relaxations Silvia Mangia1, Michael Garwood1, Ivan Tkac1, Kamil Ugurbil1, 2, Shalom Michaeli1 1University of Minnesota, Minneapolis, Minnesota, USA; 2Max Planck Institute for Biological Cybernetics , Tubingen, Germany

Adiabatic longitudinal T1ρ and transverse T2ρ rotating frame relaxation measurements were employed to probe the dynamics of cerebral metabolites, specifically of NAA and total Creatine, in the human brain at 4T. Relaxations parameters were modulated using different modulation functions of adiabatic full passage pulses. The experimental results and the theoretical analysis showed that adiabatic T1ρ and T2ρ relaxation measurements provide quantitative information on the different relaxation pathways of metabolites, such as dipolar relaxations and exchange. Our results demonstrate how detailed analysis of the fundamental MR parameters may provide an insight into the human brain function and metabolism.

12:06 694. Hahn T2 Relaxation Times of the Neurochemical Profile at 14.1T in the in Vivo Rat Brain Lijing Xin1, Giulio Gambarota1, Cristina Ramona Cudalbu1, Vladimir Mlynarik1, Rolf Gruetter1, 2 1Laboratory of Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; 2 University of Lausanne and Geneva, Switzerland

With steadily increasing magnetic field strength of new scanners for animal research (9.4T, 11.7T, 14.1T and higher) it is important to determine the tissue MR properties such as in vivo T2 relaxation time of metabolites for quantification and better understanding of the biophysical basis of relaxation. In the current study, the Hahn T2s of uncoupled and coupled spin resonances of cerebral metabolites were very similar, on the order of ~90ms in rat brain in vivo at 14.1T and only slightly reduced compared to those previously reported at 9.4 T.

12:18 695. Pseudo-Signal Injection Via Inductive Coupling Creates a Calibration Factor for Metabolite Quantification That is Immune to Coil Loading Conditions Kenneth Marro1, Donghoon Lee1, Eric Shankland1, Cecil Hayes1, Curtis M. Mathis1, Martin Kushmerick1 1University of Washington, Seattle, Washington, USA

The burden of converting MR spectral peaks to units of metabolite content can be eased by injecting a synthetic pseudo-signal for use as a calibration factor. We demonstrate that a properly designed injector coil acts as a constant voltage source on the main RF coil used to receive the signals. It therefore provides a robust calibration factor since the local B1 field generated by excited nuclei within the sample also acts as a voltage source so the real and pseudo-signals are affected equally by coil loading conditions, changes in amplifier gain and data processing algorithms.

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Cardiac Function & Wall Motion Room 717 A/B 10:30-12:30 Chairs: Han Wen and Bernd J. Wintersperger

10:30 696. Balanced Left Ventricular Myocardial SSFP-Tagging at 1.5 and 3 Tesla Michael Markl1, Stephan Scherer1, Alex Frydrychowicz1, Dieter Burger1, Annette Geibel2, Jürgen Hennig1 1Dept. of Diagnostic Radiology, Medical Physics, University Hospital, Freiburg, Germany; 2Dept. of Cardiology, University Hospital, Freiburg, Germany

The purpose of this study was to evaluate the performance of SSFP-Tagging at 1.5T and 3T and to define the ideal settings with respect to optimized tag contrast throughout the cardiac cycle for both field strengths. For SSFP-Tagging at 3T, the combination of T1 lengthening and superior myocardial SNR is highly promising and has the potential to improve the depiction of tagged myocardial function throughout the entire cardiac cycle.

10:42 697. Accelerated 3D Tagging for Quantification of Left Ventricular Dyssynchrony in Patients After Myocardial Infarction Andrea K. Rutz1, Sebastian Kozerke1, Robert Manka1, 2, Peter Boesiger1, Juerg Schwitter3 1University and ETH, Zurich, Switzerland; 2German Heart Institute, Berlin, Germany; 3University Hospital, Zurich, Switzerland

An accelerated 3D tagging acquisition was used to quantify left ventricular dyssynchrony in patients after acute myocardial infarction relative to a control population. Volumetric tagging data of the entire heart were acquired in only three breath-holds and an enhanced variant of the harmonic phase (HARP) analysis was applied for post-processing. Temporal and spatial dyssynchrony was significantly increased in patients compared to healthy volunteers (p<0.0001). Combined with CMR viability imaging, the approach shows potential to improve individual responsiveness to cardiac resynchronization therapy and to predict left ventricular remodeling.

10:54 698. Inverted Left Ventricular Apical Rotation in Patients Eligible for Cardiac Resynchronization Therapy Assessed by Tagged MRI Predicts Acute Response to Biventricular Pacing Iris K. Rüssel1, Gerjan J. de Roest1, J T. Marcus1, Cornelis P. Allaart1, Carel C. de Cock1, Marco J. Götte1, Albert C. van Rossum1 1VU University Medical Center, Amsterdam, Netherlands

Since left ventricular torsion is directly related to myocardial fiber structure, patients eligible for cardiac resynchronization therapy probably show a disorder in torsion. From tagged MRI, basal and apical rotation were determined in patients and controls. In patients, the maximum relative increase in dP/dt during biventricular pacing in different locations was measured as acute response to pacing. With respect to controls, several patients have inverted apical rotation and respond well to biventricular pacing.

11:06 699. zHARP with Dumbbells (D-ZHARP): Accelerated True 3-D Myocardial Regional Function Quantification and Tracking Khaled Zakarya Abd-Elmoniem1, Jerry L. Prince1, Matthias Stuber1 1The Johns Hopkins University, Baltimore, Maryland, USA

A fast imaging strategy is proposed to accelerate zHARP 3-D myocardial regional function imaging using a dumbbells-shaped k-space trajectory. The strategy reduce the acquisition time for zHARP imaging from two breath-holds to four heart beats without sacreficing image or calculated strain quality The scheme has the potential to significantly abbreviate a 3D cardiac strain imaging as compared to more conventional approaches.

11:18 700. Externally Calibrated ARC Parallel Imaging Reconstruction for DENSE Imaging: Initial Experience Pelin Aksit1, Ajit Shankaranarayanan2, Sandeep N. Gupta1, Philip J. Beatty2, Anthony H. Aletras3, Maggie M. Fung1, Ehud J. Schmidt1, Maureen N. Hood4, Vincent B. Ho4 1GE Healthcare, Bethesda, Maryland, USA; 2GE Healthcare, Menlo Park, California , USA; 3NIH, Bethesda, Maryland, USA; 4Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA

Un-accelerated DENSE reveals high-spatial-density myocardial strain, however requiring long breath-holds. DENSE imaging benefits from flexible parallel imaging acceleration factors to tailor acquisition time to patients’ heart rates and breath-hold capacity. A DENSE sequence was modified to allow integer and non-integer acceleration factors, with or without a variable sampling density, using the ARC parallel imaging reconstruction method. DENSE with ARC is shown, in 9 normal subjects, to provide consistent strain maps with acceptable noise levels, at acceleration factors of 1.0-2.0 (14-29 cardiac cycles scan time), suggesting its appropriateness for a range of patient populations, without compromising the ability to quantify strain.

11:30 701. Respiratory Triggered DENSE Imaging with Navigator Echoes: Initial Experience Maggie M. Fung1, Pelin Aksit1, Sandeep N. Gupta1, Ajit Shankaranarayanan2, Philip J. Beatty2, Anthony H. Aletras3, Ehud J. Schmidt4, Maureen N. Hood5, Vincent B. Ho5 1GE Healthcare, Bethesda, Maryland, USA; 2GE Healthcare, Menlo Park, California , USA; 3National Institute of Health, Bethesda, Maryland, USA; 4GE Healthcare, Boston, Massachusetts, USA; 5National Naval Medical Center, Bethesda, Maryland, USA

DENSE is a high-resolution method for evaluating cardiac contractility. Breath-held DENSE requires prolonged breath-holding (>20 sec) and is relatively low in SNR due to STEAM acquisition and limited time for T1-weighted magnetization recovery. A respiratory-triggered DENSE acquisition using dual navigator echoes was developed, increasing the magnetization recovery time from 1 heart cycle (<1s) to 1 respiratory cycle (4-5s), and thus providing a significant SNR improvement. The SNR improvement is shown to improve the reliability of the resulting strain maps, or, alternatively, it allows the use of greater acceleration factors to reduce the scan time.

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11:42 702. Strain-Encoded (SENC) MR Imaging with Improved Signal-To-Noise Ratio Using Balanced Steady-State Free Precession Tamer A. Basha1, ElSayed H. Ibrahim1, Monda L. Shehata1, Robert G. Weiss1, Nael F. Osman1 1Johns Hopkins University, Baltimore, Maryland, USA

Strain Encoding (SENC) is a new MRI technique for quantifying regional myocardial strain. However, it suffers from its intrinsically low SNR. The purpose of this work is to improve the SENC images SNR by combining it with the SSFP pulse sequence which is known for its intrinsically high SNR and excellent blood-tissue contrast. This combination could offer substantial improvement in the image SNR, and thereby enhances the qualitative and quantitative analysis of heart wall motion. The SENC-SSFP sequence was tested in phantom and human experiments, and showed significant improvement (about 100%) in SNR compared to conventional SENC.

11:54 703. Segmental Left Ventricular Function Depends on Gender and Age: New Findings by High Temporal Resolution Tissue Phase Mapping Daniela Foell1, Elfriede Schilli1, Felix Staehle1, Bernd Jung1, Christoph Bode1, Juergen Hennig1, Michael Markl1 1University Hospital Freiburg, Freiburg, Germany

Using CINE phase contrast MRI (Tissue Phase Mapping, TPM) we analyzed myocardial velocities in all spatial directions of the left ventricle. A segmental assessment covering the entire left ventricle of 60 healthy volunteers in 3 age-groups was performed. Our data clearly demonstrate age- and gender specific alterations of regional myocardial motion. Most noticeably, we found an increased reduction in regional diastolic velocities in women during the process of aging, whereas myocardial velocities of young women exceeded those of age-matched men. These differences may have been missed, if analysis of cardiac function was restricted to an evaluation of global velocities.

12:06 704. Myocardial Acceleration Calculation from Highly Time Resolved Tissue Phase Mapping Felix Staehle1, Bernd André Jung1, Daniela Föll1, Elfriede Schilli1, Jürgen Hennig1, Michael Markl1 1University Hospital Freiburg, Freiburg, Germany

This abstract is a feasibility study of the calculation of acceleration data from highly time resolved tissue phase mapping (TPM) of the myocardium. Velocity data of a group of 10 healthy volunteers and two patients were measured and evaluated by voxel tracking between successive time frames and a non-linear curve fit to determine the acceleration value. The mean time courses of acceleration data show a different sensitivity to pathology than the velocity data. The evaluation of peak acceleration values and corresponding times-to-peak support the feasibility of acceleration to provide valuable information about various pathologies.

12:18 705. Non Invasive Measurement of the Volume-Pressure Work of the Human Heart by Cardiac MR Elastography Thomas Elgeti1, Jens Rump1, Dieter Klatt1, Uwe Hamhaber1, Sebastian Papazoglou1, Jürgen Braun1, Bernd Hamm1, Ingolf Sack1 1Charité Universitätsmedizin Berlin, Berlin, Germany

Wave amplitude variation MR-Elastography enables non invasive measurement of the volume-pressure work of the human heart in 6 healthy volunteers.

HANDS-ON WORKSHOP 1 (REPEAT) Neuro and Musculoskeletal Protocol Optimization Philips Medical Systems Room 709 10:30 – 12:30

Siemens Medical Solutions Room 711 10:30 – 12:30

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SILVER CORPORATE MEMBER LUNCHTIME SYMPOSIUM Bruker BioSpin Hall F 12:30 – 13:30

SPECIAL SYMPOSIUM Unsolved Problems and Unmet Needs Room 801 A/B 13:30 - 15:30 Chairs: Daniel K. Sodickson

Beyond BOLD: Clinical Applications, Surrogates, and Mechanisms of Functional MRI 13:30 Proffered Abstract: MRI of Chronic Low Back Pain Mark Oswood 13:50 Proffered Abstract: Can We See Blood Vessel Dilation Responsible for fMRI? Mario Forjaz Secca 14:10 Invited Talk: What is Known and What is Not About BOLD Mechanisms and Sources of fMRI? Peter A. Bandettini Will MR Replace the Microscope? High-Performance MR In Vivo, Postmortem, and in Engineered Tissues 14:30 Proffered Abstract: Which Clinical Application(s) Would Best Benefit from Submillimeter High T1 contrast Whole

Brain Images at 7Tesla with Simultaneous Angiography Perfectly Coregistered with Anatomical Images Pierre-Francois Van de Moortele

14:50 Proffered Abstract: The Future of MRI in Forensic Investigations After Death Hedwig Tromp 15:10 Invited Talk: Beyond In Vivo Unmet Needs for MR in Tissue Engineering Richard G. S. Spencer

MRI & MRS of Liver Steatosis Room 716 A/B 13:30-15:30 Chairs: Claude B. Sirlin and Brian J. Soher

13:30 706. Hepatic Fat Quantification by Low Flip-Angle Multi-Echo Gradient-Echo MR Imaging: A Clinical Study with Validation with MR Spectroscopy Takeshi Yokoo1, Mark Bydder1, Gavin Hamilton1, Michael S. Middleton1, Jefferey Schwimmer, Joel Lavine, Terek Hassanein, Heather Patton, Nicholas Pinto1, Richard Znamirowski1, Lillian Pacheco1, Claude B. Sirlin1 1University of California at San Diego, San Diego, California , USA

Noninvasive hepatic fat quantification is an increasingly important area of application of MR technology. Several new MR imaging strategies have been proposed in an attempt to account for the T1 and T2* relaxation effects, and to improve the accuracy and reliability of fat quantification. In this presentation, we describe results from a prospective clinical study in which low flip-angle multi-echo gradient-echo imaging is used to predict the proton-density fat fraction measured by MR spectroscopy.

13:42 707. Quantification of Hepatic Steatosis with MRI: Validation in the Ob/ob Mouse at 3T Catherine Diane Gard1, Thomas Frances Warner1, Huanzhou Yu2, Ann Shimakawa2, Charles A. McKenzie3, Jean H. Brittain4, Scott B. Reeder1 1University of Wisconsin-Madison, Madison, Wisconsin, USA; 2GE Healthcare, Menlo Park, California , USA; 3University of Western Ontario, London, Canada; 4GE Healthcare, Madison, Wisconsin, USA

Early diagnosis of hepatic steatosis with non-invasive quantitative biomarkers is a critical unmet need in the detection and evaluation of non-alcoholic fatty liver disease. In this work we validate fat quantification of hepatic steatosis in a range of tissue fat percentages in the ob/ob mouse model of hepatic steatosis using IDEAL (Iterative Decomposition with Echo Asymmetry and Least-squares estimation). We compare fat-fraction measured with IDEAL to histological evaluation and total lipid extraction using the Folch method. Excellent correlation between IDEAL, histology and lipid extraction is observed. These results demonstrate validation of MRI for quantification of hepatic steatosis in vivo.

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13:54 708. Rapid T2 and Lipid-Water Imaging of the Liver with Radial IDEAL GRASE Maria I. Altbach1, Zhiqiang Li1, Scott W. Squire1, Arthur F. Gmitro1, Ali Bilgin1, Christian Graff1, Eric Outwater1 1University of Arizona, Tucson, Arizona , USA

A radial Gradient and Spin Echo (GRASE) method has been developed for liver imaging. The method allows for the quantitative characterization of liver pathologies based on T2 values and lipid-water information.

14:06 709. Correction for Multipeak Fat Spectrum When Estimating T2* in the Presence of Fat Huanzhou Yu1, Scott B. Reeder2, Ann Shimakawa1, Charles A. McKenzie3, Jean H. Brittain4 1GE Healthcare, Menlo Park, California , USA; 2University of Wisconsin, Madison, Wisconsin, USA; 3University of Western Ontario, London, Canada; 4GE Healthcare, Madison, Wisconsin, USA

Simultaneous estimation of water, fat and T2*, achieved by algorithms such as T2*-IDEAL, is important in the evaluation hepatic fatty infiltration and iron overload. Fat was previously modeled as a single resonant frequency. However, fat has multiple spectral peaks that confound the estimation of fat content and T2*. In particular, T2* may be substantially under-estimated in the presence of fat, which would lead to overestimation of liver iron stores. In this work, we model a more accurate fat spectrum in the T2*-IDEAL algorithm and propose a spectrum self-calibration method that provides improved T2* estimation with no additional data required.

14:18 710. Quantification of Hepatic Steatosis with MRI: the Effects of Accurate Fat Spectral Modeling Scott B. Reeder1, 2, Philip Robson2, Huanzhou Yu3, Ann Shimakawa3, Catherine D. Gard1, Charles A. McKenzie4, Jean H. Brittain5 1University of Wisconsin, Madison, Wisconsin, USA; 2Beth Israel-Deaconess Medical Center, Boston, Massachusetts, USA; 3GE Healthcare, Menlo Park, California , USA; 4University of Western Ontario, London, Canada; 5GE Healthcare, Madison, California , USA

Accurate non-invasive quantification of hepatic steatosis is an important unmet need in the diagnosis and management of non-alcoholic fatty liver disease (NAFLD). In this work, we describe the use of IDEAL, a chemical-shift based water-fat separation method, with a modified reconstruction that accounts for the signal from the multiple peaks of fat (“multipeak reconstruction”) and compare this method with MR spectroscopy (PRESS) in 31 patients. Excellent agreement between IDEAL and PRESS with a slope near 1.0 is achieved only when multipeak reconstruction is used, demonstrating the importance of all spectral peaks of fat when quantifying hepatic fat content.

14:30 711. Fat Quantification Using SPIO as a Surrogate Marker for Iron Accumulation in the Liver Sebastian Sugay1, Mark Bydder2, Takeshi Yokoo2, Gavin Hamilton2, Nick Pinto2, Richard Znamirowski2, Eli Soumekh2, Tanya Wolfson2, Lillian Pacheco2, Claude Sirlin2 1John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA; 2University of California, San Diego, California , USA

In this abstract, we show that accounting for T2* decay of water and fat using a 6-point imaging protocol produces stable measurements in fat fraction (FF) despite experimental, SPIO-induced perturbations in T2*. As T2* decreased, the 6 point FF measurements remained unchanged, while the 2 point measurements underestimated FF.

14:42 712. Quantification of the Hepatic Fatty Infiltration and the Metabolite Concentrations Using Magnetic Resonance Spectroscopy and in and Out of Phase Imaging Sophie Cavassila1, Adriana Bucur1, Hélène Ratiney1, Cristina Cudalbu1, Olivier Beuf1, Frank Pilleul1, 2 1CNRS UMR 5220, Inserm U630, INSA-Lyon, Université de Lyon, Université Lyon 1, Villeurbanne, France; 2Hospices Civils de Lyon, Lyon, France

Despite the increasing prevalence of non-alcoholic fatty liver disease, the criteria used to diagnose the disorder remain poorly defined. Non invasive methods such as proton magnetic resonance spectroscopy (MRS), diffusion-weighted imaging, double-echo imaging (DEI) have been developed in order to substitute liver biopsy which is the gold standard. For this study, twelve patients with suspected liver diseases were investigated by MR imaging and spectroscopy of the liver. Both saturated lipids/water and unsaturated lipids/water ratios determined by MRS showed strong correlations with the percentage of liver steatosis determined by DEI. Moreover, the levels (relative to water) of the groups of metabolites at 3.2ppm and 3.5ppm determined by MRS showed also correlations with the percentage of liver steatosis determined by DEI.

14:54 713. Validation of Hepatic Fat Quantified on 3T MRI Via Histopathologic Correlation in Patients with Non-Alcoholic Steatohepatitis Hero K. Hussain1, Elif A. Oral, Suzan Rohrer, Barbara McKenna, Frank J. Londy, Marko K. Ivancevic, Thomas L. Chenevert 1University of Michigan, Ann Arbor, Michigan, USA

The dual-flip MRI method at 3T is reliable to measure hepatic fat. It correlates well with quantitative histopathologic measures and MRS, though unlike MRS, offers full-liver mapping of fat content and overcomes heterogeneity.

15:06 714. Non-Invasive Quantification of Hepatic Steatosis with 3.0 Tesla Magnetic Resonance Spectroscopy in Patients Undergoing Liver Resection Jochem Reinier van Werven1, H. A. Marsman1, A. J. Nederveen1, F. J. ten Kate1, T. M. van Gulik1, J. Stoker1 1Academic Medical Center, Amsterdam, Netherlands

Hepatic steatosis is a risk factor in liver surgery. Liver biopsy remains the gold standard. 1H-MRS is a non-invasive alternative. The purpose of this study was to quantify hepatic steatosis with 3.0T 1H-MRS in patients undergoing liver resection.1H-MRS was performed preoperatively in twenty patients undergoing liver resection. Intra-operatively biopsies were taken for histopathological and biochemical analysis. 1H-MRS measurements of hepatic fat correlated with these assessments. 1H-MRS measurements could differentiate between different grades of hepatic steatosis.3.0T 1H-MRS can measure hepatic fat content and correlates with histopathological and biochemical analysis. It is also able to discriminate between grades of steatosis.

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15:18 715. Effects of T1 and T2* Relaxation on Fat Quantification by Gradient Echo Imaging Mark Bydder1, Takeshi Yokoo1, Gavin Hamilton1, Michael S. Middleton1, Claude Sirlin1 1University of California San Diego, San Diego, California , USA

MRI is increasingly applied to the non-invasive assessment of steatosis. A linear correlation is often assumed between MRI estimates of fat and a gold standard (e.g. histology). We show that T1 and T2* relaxation can introduce nonlinearity in a typical liver imaging protocol.

Advanced Imaging of Brain Tumors Room 701 A 13:30-15:30 Chairs: Michael Alan Kraut and Meng Law

13:30 716. 31P MRS of Human Brain Tumors at 3T Using 1H –31P Polarization Transfer Jannie P. Wijnen1, Dennis WJ Klomp1, Arend Heerschap1 1Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands

Although 31P MRS of tumors in humans provides more relevant information on phospholipid metabolism than 1H MRS it is hampered by sensitivity limitations. In this study we demonstrate the feasibility of an optimized localized 1H-31P polarisation transfer method to examine phosphorylated compounds in brain tumors with increased sensitivity and resolution at 3T. The changes observed in tumor tissue for ratios of individual phosphomonoester and diester compounds may be valuable biomarkers for tumor diagnosis and treatment follow up.

13:42 717. Multi-Exponential Diffusion Imaging: Clinically Feasible Multiple B-Value Diffusion Imaging for High Grade Gliomas Inas S. Khayal1, 2, Colleen McGue1, Soonmee Cha1, Susan M. Chang1, Roland G. Henry1, Sarah J. Nelson1 1University of California, San Francisco, San Francisco, California , USA

The goal of this study was to develop and validate a two b-value diffusion sequence capturing the deviation from mono-exponential decay signal (dS) in a time efficient clinical scan; and to test how this signal can differentiate tumor (contrast enhancing lesion) from edema (non-enhancing lesion) as compared to the conventional apparent diffusion coefficient (ADC) and fractional anisotropy (FA) in high grade gliomas. This technique shows spatial variation within enhancing and non-enhancing lesions which may be of interest for tumor characterization and may be utilized in distinguishing progressive tumor from treatment response. Further studies will verify this variation with image-guided biopsy.

13:54 718. The Functional Diffusion Map (FDM) as an Early Imaging Biomarker for High-Grade Glioma: Correlation with Conventional Radiologic Response and Overall Survival Craig J. Galbán1, Daniel A. Hamstra1, Charles R. Meyer1, Timothy D. Johnson1, Pia C. Sundgren1, Christina Tsien1, Theodore S. Lawrence1, Larry Junck1, David J. Ross1, Alnawaz Rehemtulla1, Brian D. Ross1, Thomas L. Chenevert1 1University of Michigan, Ann Arbor, Michigan, USA

We ascertained if diffusion MRI, by functional diffusion mapping (fDM), could directly predict patient survival. Sixty patients with high grade glioma undergoing radiation therapy were enrolled in a study of intra-treatment MRI 1, 3, and 10 weeks after the initiation of treatment. Compared to conventional neuro-imaging, fDM provided an earlier assessment of equal predictive value. While the combination of fDM and radiological response provided a more accurate prediction of patient survival than either metric alone.

14:06 719. A Novel Membrane-Permeant Contrast Agent for Ultra-Sensitive Brain Tumor Detection by MRI Mohanraja Kumar1, Zdravka Medarova1, Pamela Pantazopoulos1, Anna Moore1 1Massachusetts General Hospital, Charlestown, USA

One of the key challenges hindering effective therapy against brain cancer is defined by the inability to detect brain tumors at an early stage. With this in mind, we designed a novel membrane-permeant contrast agent, MN-MPAP, which consists of a superparamagnetic iron oxide nanoparticles, for MR imaging, labeled with the near-infrared dye Cy5.5, for near-infrared optical imaging, and conjugated to myristoylated polyarginine peptides (MPAP), as a membrane translocation module. In vivo MRI established the value of MN-Cy5.5-MPAP for tumor localization and delineation. T2 map analysis demonstrated higher accumulation of MN-Cy5.5-MPAP in tumors than control MN-Cy5.5, as reflected by the change in tumoral T2 relaxation times following injection of the contrast agent.

14:18 720. Glioma Detection Maximized Through Intracellular and Extracellular MR-Guided Optical Fluorescence Tomography Summer Gibbs-Strauss1, Julia A. O'Hara, Scott C. Davis1, Brian William Pogue1 1Dartmouth College, Hanover, New Hampshire, USA

MR-guided optical fluorescence spectroscopy of glioma brain tumors was studied, contrasting the detectability of the 9L tumor with the U-251 tumor. While the 9L tumor was delinated by T1 Gd-contrast MR, the U-251 was not as well resolved. Intracellular and extracellular optical contrast agents however showed significantly better delineation of the U-251 tumor though, due to increased metabolic function.

14:30 721. Improved Diffusion MR Fiber Tracking for Neurosurgical Applications Jeffrey I. Berman1, Danny J. Clark1, Mitchel S. Berger1, Roland G. Henry1 1University of California San Francisco, San Francisco, California , USA

In this study, a residual bootstrap probabilistic q-ball fiber tracking technique was used to delineate the motor tract in four brain tumor patients. Results of probabilistic and deterministic q-ball fiber tracking are compared to the currently used DTI fiber tracking technique. Q-ball fiber tracking methods were able to delineate the motor tract to lateral portions of the motor cortex while DTI fiber tracking could not traverse regions of crossing white matter fibers. The HARDI acquisition used for this study was acquired in a clinically feasible timeframe and q-ball fiber tracking has the potential to be routinely used for surgical planning.

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14:42 722. Random-Walk Based Tractography Simulation for the Growth of Brain Tumors Poe-Jou Chen1, 2, Wei-Ting Zhang2, Rakesh K. Jain3, T T. Batchelor3, A Gregory Sorensen2 1Massachusetts Institute of Technology, Cambridge, Massachusetts, USA; 2Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, USA; 3Massachusetts General Hospital, Charlestown, Massachusetts, USA

A random walk based tractography model is proposed to simulate the growth of glioblostams multiforma (GBMs). The simulated tumor evolution was compared with the real growth observed with two MR images of a patient acquired with one month difference. Results demonstrate the potential of this random walk model and the proposed model will be evaluated on more patient data to prove its feasibility in real clinical applications

14:54 723. Differentiation of Low-Grade Glioma Subtypes Using Mutiparametric MR Data Wei Bian1, Inas S. Khayal, 12, Colleen McGue1, Suja Saraswathy1, Soonmee Cha, Susan M. Chang1, Sarah J. Nelson1 1University of California San Francisco, San Francisco, California , USA; 2UCSF/UCB Joint Graduate Group in Bioengineering, San Francisco, California , USA

To differentiate low-grade glioma (LGG) subtypes, forty five newly diagnosed grade II glioma patients (17 oligodendroglioma, 11 astrocytoma, and 17 oligoastrocytoma) underwent proton MR spectroscopy imaging (MRSI), diffusion weighted imaging (DWI), and perfusion weighted imaging (PWI). Normalized metabolite intensities were estimated from MRSI, apparent diffusion coefficient (ADC) from DWI, and relative cerebral blood volume (rCBV) from PWI. Discriminant analysis was performed to determine the parameters that better differentiate LGG subtypes. Median ADC and 25th percentile rCBV helped differentiate oligodendroglioma from astrocytoma, and median ADC and Choline helped differentiate oligodendroglioma from oligoastrocytoma. Better classification accuracy was achieved when using these mutiparametric MR data.

15:06 724. Monitoring Brain Tumor Response to Radiation by Sodum MR Imaging Keith Thulborn1, Fred Damen, Aiming Lu1, Ian Atkinson1, John Villano1, Howard Halpern, Bulent Aydogan2, Michael Flannery1, Hagai Ganin1 1Univ. of Illinois at Chicago, Chicago, Illinois, USA; 2Univ. of Chicago, Chicago, Illinois, USA

Quantitative sodium imaging can be used to follow brain tumor response to radiation during initial treatment. A lack of response predicts treatment failure and its location. Such data allows modification of the initial treatment and the possibility to achieve an improved outcome for these patients.

15:18 725. Which is Best for Classifying Brain Tumours from 1H Spectra: Expert Interpretation, Metabolite Ratios, Classifiers or the INTERPRET Decision-Support System? Margarida Julià-Sapé1, 2, Indira E. Coronel2, Carles Majós3, Ana Paula Candiota1, 2, Marta Serrallonga3, 4, Monica Cos3, Carles Aguilera3, Juan José Acebes5, John R. Griffiths6, Carles Arús, 12 1CIBER-BBN, Centro de Investigación Biomédica en Red en bioingenieria, Biomateriales y Nanomedicina, Cerdanyola del Valles, Spain; 2Universitat Autonoma de Barcelona, Cerdanyola del Valles, Spain; 3CSU de Bellvitge, L’Hospitalet de Llobregat, Spain; 4Telemedicine Clinic, Barcelona, Spain; 5Hospital Prínceps d’Espanya, CSU de Bellvitge, L’Hospitalet de Llobregat, Spain; 6Cancer Research UK Cambridge Research Institute, Li Ka Shing Centre, Cambridge, UK

Four methods for analysis of MR spectra were tested to determine which method worked best. Data from 40 consecutive adult patients with abnormal brain masses were prospectively analyzed. Formal criteria for MRS evaluation were used: a) Structured description of the MRS by expert spectroscopists; b) Analysis with the INTERPRET decision-support system; c) Calculation of a mIno/Gly ratio; d) Classifiers at short and at long TE. The best system was the INTERPRET DSS. It performed better than expert evaluation, as its embedded classifier incorporates quantitative measurements, whereas expert interpretation is by nature, qualitative.

MRA: Contrast Without the Agent Room 701 B 13:30-15:30 Chairs: Henrik Michaely and Mitsue Miyazaki

13:30 726. Improving Non-Contrast Enhanced SSFP Angiography with Compressed Sensing Tolga Çukur1, Michael Lustig1, Dwight Georger Nishimura1 1Stanford University, Stanford, California , USA

Flow-independent angiography offers the ability to produce vessel images without contrast agents. 3D magnetization-prepared balanced SSFP can be used to acquire these angiograms, where the phase encodes are interleaved and preparation is repeated prior to the start of each interleave. However, frequent repetition of the preparation significantly reduces the scan efficiency. The sparsity of the angiograms allows for the use of compressed sensing to undersample the phase encodes and save scan time. These savings can be allotted for preparing the magnetization more often, or alternatively, improving resolution.

13:42 727. Flow-Dependent Arterial and Venous Imaging by Non-Contrast-Enhanced Subtraction Angiography Andrew Nicholas Priest1, Martin John Graves1, Pauline Wong1, David John Lomas1 1Addenbrooke's Hospital and University of Cambridge, Cambridge, UK

Preparation modules containing ‘diffusion weighting’ or motion-sensitising gradients have recently been used to suppress the blood signal in images of the vessel wall. Since the blood suppression can be selectively applied, it is possible to produce subtraction images which selectively depict the vascular anatomy while suppressing the signal from static tissues. Furthermore, by acquiring images with different degrees of suppression, images which selectively depict either arteries or veins can be produced. This work demonstrates high-resolution 3D vascular images in the lower leg in healthy volunteers, and might be applied to clinical situations which currently require contrast agent administration.

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13:54 728. Quantification of Reactive Hyperemia in the Femoral Artery and Vein by MRI-Based Blood Oximetry Michael Langham1, Tom Floyd1, Jeremy Magland1, Emile Mohler, III1, Felix W. Wehrli1 1University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA

We demonstrate MR susceptometry-based oximetric quantification of reactive hyperemia in response to cuff-induced ischemia by making direct time-course measurement of oxygen saturation level in the femoral artery and vein of both normal subjects and patients with peripheral arterial disease (PAD). The washout time and the upslope were significantly longer and less, respectively, for PAD patients compared to normal. The washout time refers to the time required to observe oxygen depleted venous blood that is washed out of the capillary bed during the reactive hyperemia and the upslope correspond to the reoxygenation rate in the vein after the washout.

14:06 729. Interactive Two-Dimensional Fresh Blood Imaging Pauline Wong1, Martin John Graves1, David John Lomas1 1University of Cambridge and Addenbrooke's Hospital, Cambridge, UK

Fresh Blood Imaging, a non-contrast enhanced 3D MRA technique, has been implemented for the real-time imaging environment and demonstrated in healthy volunteers. As the technique is directly related to the pulsatility of the vessel flow, a time consuming prep scan is typically used to calculate the systole and diastole trigger delays. We have implemented a 2D version in real-time and used a rapid flow measurement as the prep scan for calculating trigger delays. Localisation, navigation, flow measurement and FBI angiography were performed in a single scan/sequence. Results in peripheral vessels are shown with Tacq~0.5-1min (8 averages).

14:18 730. A Novel Non-Contrast MR Angiography Technique Using Triggered Non-Selective Refocused SPACE for Improved Spatial Resolution and Speed Jian Xu1, Peter Weale1, Laub Gerhard1, Peter Schmitt2, Jaeseok Park2, Bernd Stoeckel1, Qun Chen3, Ruth P. Lim3, Andrew Hardie3, Pippa Storey3, Elizabeth Hecht3, Kellyanne Mcgorty3, Vivian S. Lee3 1Siemens Medical Solutions USA Inc., Malvern, Pennsylvania, USA; 2Siemens Medical Solutions, Erlangen, Germany; 3New York University, New York, New York, USA

A Novel Non-contrast MRA Technique using Triggered 3D SPACE for Improved Spatial Resolution and Speed is developed, which uses selective RF excitation, non selective RF refocusing pulses and variable flip angles for contrast manipulation. SPACE helps achieve lower SAR and shorter ETS, resulting in total acquisition windows of around 100ms, a slice turbo factor in 3D direction can speed up the acquisition. We performed a comparison between the SPACE and the TSE based approaches in terms of spatial resolution and reduced blurring and small vessel conspicuity.

14:30 731. Noncontrast MRA of Renal Artery Using Flow-Prep FIESTA for Evaluation of Patients with Suspected Renal Tumor: Comparison of Dynamic Contrast MRA Takayuki Masui1, Motoyuki Katayama1, Kimihiko Sato1, Hidekazu Seo1, Hiroki Ikuma1, Akihiko Kutsuna1, Masayoshi Sugimura1, Kazuhiko Ito1, Mitsuaharu Miyoshi2, Tetsuji Tsukamoto2 1Seirei Hamamatsu General Hospital, Hamamatsu, Japan; 2GEYMS, Hino, Japan

In the evaluation of 63 patients with suspected renal tumor, respiratory triggered ECG gated non-contrast (NC) MRA using FIESTA with Flow-Preparation pulse and contrast dynamic (C) MRA were performed. With successfully triggered ECG, identical information of the middle to proximal renal arteries and entire abdominal aorta could be obtained with NC and C-MRA. Peripheral portions of the renal arteries were better depicted on NC MRA than C MRA without overlap of the other structures. Consequently, in case of contraindication to use of MR contrast agents, NC MRA can give anatomical information of renal arteries, preoperatively.

14:42 732. STARBURST Peripheral MR Venography Robert R. Edelman1, Ioannis Koktzoglou1 1Evanston Northwestern Healthcare, Evanston, Illinois, USA

STARBURST (Selectively Targeted Angiographic Rendering using Blood’s Unique Relaxation properties and Subtraction Technique) was used to create flow-independent peripheral MR venograms. The method involves the acquisition of two image sets (with one set being tagged by a spatially non-selective radiofrequency pulse) that are subtracted to render an angiogram. Extensive lengths of the veins were shown including submillimeter branch vessels; the arteries were almost completely suppressed with the application of spatially selective pre-inversion. The results demonstrate the feasibility of high resolution MR venography of the lower extremities with suppression of arterial signal and without the need for contrast administration.

14:54 733. Non-Contrast Enhanced Renal MR Angiography with PC VIPR Kevin Michael Johnson1, Darren Lum1, Chistopher J. Francois1, Scott B. Reeder1, Reede F. Busse2, Tom M. Grist1, Oliver Wieben1 1University of Wisconsin - Madison, Madison, Wisconsin, USA; 2MR Applied Science Lab, GE Healthcare, Madison, Wisconsin, USA

This study investigates the use of a modified phase contrast VIPR sequence for volumetric 3D velocity imaging of the renal arteries without a contrast agent. With the addition of adaptive respiratory gating, high quality angiograms were obtained in volunteers and patients. This approach provides an excellent alternative for patients that are excluded from contrast enhanced MRA otherwise. This includes subjects with compromised kidney function due to potential nephrogenic systemic fibrosis issues and kidney transplant patients for regular follow-ups.

15:06 734. Micro MR Angiography of the Finger as a Potential Biomarker in Systemic Sclerosis Jinnan Wang1, Vasily L. Yarnykh1, Baocheng Chu1, Jerry Molitor2, Richard Nash, Fei Liu1, Stephen Schwartz1, Chun Yuan1 1University of Washington, Seattle, Washington, USA; 2University of Minnesota, Minneapolis, Minnesota, USA

In this study, we report the initial experience in high resolution MR angiography of scleroderma digital vasculature imaging. Micro MR angiography sequence was optimized for finger vessel imaging. Based on the angiography images, significant differences were found on arterial lumen size, number of visible veins and vascular scores, between scleroderma patients and normal volunteers. These quantitative variables can be potentially used as prospective biomarkers for scleroderma disease evaluation.

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15:18 735. Carotid Artery Imaging at 7T: SNR Improvements Using Anatomically Tailored Surface Coils Marco Piccirelli1, Nicola DeZanche1, Jurek Nordmeyer-Massner1, Michaela Soellinger1, Michael Wyss1, Gérard Crelier1, Klaas Paul Pruessmann1, Sebastian Kozerke1 1University and ETH Zurich, Zurich, Switzerland

Shape, blood flow, and wall shear stress of the carotid artery are associated with its function. The determination of related parameters relies on accurate angiographic and velocity data. We present a dedicated 7T receive-only, two-element surface coil for carotid imaging. The coil geometry was tailored to the neck and jaw anatomy. Comparison of the surface coil with a standard T/R-volume head coil showed a drastic SNR improvement making high-quality phase-contrast imaging possible. Particle traces in small branches of the carotid blood flow demonstrate the excellent SNR performance of the coil.

SPECIAL SYMPOSIUM So You Want to Start an MRI Company? What You Need to Know Room 715 A/B 13:30 – 15:30 Chairs: Harald H. Quick and Orlando P. Simonetti

Educational Objectives: Upon completion of this course, participants should be able to:

• Define the basic mechanisms of starting a MRI company; • Recognize what types of MRI technological developments can be patent protected; • Describe the challenges and methods of commercialization of MR technology in an academic setting; and • Identify potential sources of funding for MRI start-up companies.

14:00 Patenting of MR Technology

Mark Jay

14:20 Commercialization of MR Technology in the Academic Environment Jean Schelhorn 14:40 NIH SBIR/STTR Program Keyvan Farahani

15:00 MRI Software Business Startup Robert Judd 15:20 MRI Hardware Business Startup Florian Odoj

15:40 Panel Discussion

Emerging Clinical Techniques in MSK MRI Room 717 A/B 13:30-15:30 Chairs: Bernard J. Dardzinski and Ravinder R. Regatte

13:30 736. CSPAMM Tagging of the Extraocular Muscles During Eye Motion: New Insights Marco Piccirelli1, 2, Roger Luechinger1, Andrea Kaspar Rutz1, Veit Sturm3, Klara Landau3, Peter Boesiger1, Oliver Bergamin3 1University and ETH Zurich, Zurich, Switzerland; 2University Hospital Zurich, n/a, Switzerland; 3University Hospital Zurich, Switzerland

We studied the local deformation pattern along the horizontal extraocular muscles (EOMs), using CSPAMM Tagging, in seven healthy subjects and in a patient with Duane’s syndrome type 1 (DST1). The optic nerve, the medial, and the lateral rectus muscles were tracked with a mesh algorithm using HARP. The healthy EOM deformation patterns during left-to-right and right-to-left gaze were similar, suggesting that both horizontal muscles are active during smooth pursuit. The anterior and posterior muscle segments of the DST1 EOMs had different contraction and relaxation patterns. CSPAMM with mesh postprocessing differentiated the pathologic from the physiologic EOM local deformation pattern.

13:42 737. Strain Distribution in the Biceps Femoris Long Head Muscle as Determined by Real-Time MRI Tagging Niccolo Fiorentino1, Jonathan Lin2, Michael Guttman2, Nicholas Evoy2, Silvia Blemker1, Elliot McVeigh, 23 1University of Virginia, Charlottesville, Virginia , USA; 2National Institutes of Health, Bethesda, Maryland, USA; 3Johns Hopkins, Baltimore, Maryland, USA

MRI tagging was used to measure engineering strain in the biceps femoris long head muscle, the most commonly injured hamstrings muscle. Imaging of normal volunteers took place in a 70cm wide bore scanner during flexion-extension of the knee. Engineering strain was defined as the difference in distance between tag lines on the initial tagged image and an image 200 ms post-tagging divided by the distance on the original image. Results were obtained along the muscle’s anterior border (4.8%), along the midline (0.9%), and along the posterior border (4.7%), suggesting strain is not uniform across the biceps femoris long head muscle.

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13:54 738. Ultrashort TE (UTE) Imaging of the Temporomandibular Joint (TMJ) at 3T Christine B. Chung1, Jiang Du1, Won Bae1, Sheronda Statum1, Richard Znamirowski1, Atsushi Takahashi2 1University of California, San Diego, San Diego, California , USA; 2GE Healthcare Technologies, Menlo Park, California , USA

The temporomandibular joint (TMJ) is an articulation of anatomic and biomechanical complexity. It is affected by a variety of osseous and soft tissue conditions that alter structure and compromise function. The fibrocartilaginous nature of TMJ tissues comprised largely of short T2 components, make their MR imaging evaluation technically difficult. Ultrashort echo time (UTE) pulse sequences allow signal from short T2 tissue components to be detected. Here we report the application of UTE sequences to imaging and quantification of TMJ of cadaver samples and volunteers on a clinical 3T scanner.

14:06 739. Ultrashort TE (UTE) Imaging: Application to Magic Angle Study of the Achilles Tendon and Enthesis at 3T Jiang Du1, Byung C. Pak1, Atsushi Takahashi2, Richard Znamirowski1, Sheronda Statum1, Christine B. Chung1, Graeme M. Bydder1 1University of California, San Diego, San Diego, California , USA; 2GE Healthcare Technologies, Menlo Park, California , USA

Collagen fibers in tendons and enthuses are highly ordered. The protons within the bound water are subject to dipolar interactions which strength depends on the orientation of the fibers to the static magnetic field B0. These dipolar interactions are minimized near 55 degree relative to B0 field, resulting in a increase in T2 and MR signal. Here we applied UTE sequence to quantitatively investigate this signal and T2 dependence on orientation angle on a clinical 3T scanner.

14:18 740. Clinical Evaluation of Two- Point Dixon Based Fat-Water Separation with Conventional Fat Suppressed 2D Fast Spin Echo Imaging David W. Stanley1, Manojkumar Saranathan2, Anthony T. Vu3, Marilyn B. Wood4, Jeffrey R. Bond4, John A. Skinner4, Matthew A. Frick4 1GE Healthcare, Rochester, Minnesota, USA; 2Global Applied Science Laboratory, GE Healthcare, Rochester, Minnesota, USA; 3GE Healthcare, Waukesha, Wisconsin, USA; 4Mayo Clinic, Rochester, Minnesota, USA

Many pathologic, cystic or solid conditions involving the musculoskeletal system are detected on the basis of increased signal on T2-weighted images. Conventional fat suppression techniques such as chemical fat saturation are suboptimal at field strengths of 3T or higher due to B0 and B1 inhomogeneity issues leading to non-uniform fat signal across the imaged FOV.We investigated the clinical performance of a two-point Dixon-based fat-water separation scheme compared to conventional fat suppression techniques in 2D FSE imaging of the lower extremities.

14:30 741. Quantification of the Relaxation Times of Combined CT and MR Contrast Agents for Optimal Imaging at MR Arthrography Taylor Handley1, Chen Lin1, Robert Choplin1, Kenneth Buckwalter1 1Indiana University School of Medicine, Indianapolis, Indiana, USA

This purpose of this paper is to measure the T1 and T2 relaxation times of three different gadolinium contrast agents, gadobenate dimeglumine (MultiHance), gadoteridol (ProHance), and Gd-DTPA (Magnevist) when mixed with iodinated contrast media for MR arthrography at 0.7T, 1.5T and 3.0T. T1 and T2 maps were generated for different concentrations of gadolium agents and magnetic field strengths to generate a generalized curve fit using a least squares regression model. Although the greatest T1 relaxation was found with the gadobenate dimeglumine mixture, it was much less than what might be expected.

14:42 742. 3T Skin Imaging Joëlle Karine Barral1, Neal K. Bangerter1, Bob S. Hu2, Dwight George Nishimura1 1Stanford University, Stanford, California , USA; 2Palo Alto Medical Foundation, Palo Alto, California , USA

The requirements of very high resolution and adequate SNR in clinically feasible scan times make clinical skin imaging challenging. To evaluate the feasibility of skin imaging as a clinical modality, high-resolution versions of three pulse sequences - spoiled GRE, alternated balanced SSFP, and FLASE - were compared on a 3T system. The main skin layers were identified will all sequences.

14:54 743. Partial Weight Bearing Patellofemoral Kinematics Measured with MRI After Total Knee Arthroplasty R. Dana Carpenter1, Jean Brilhault1, Sharmila Majumdar1, Michael D. Ries1 1University of California, San Francisco, California , USA

Patellofemoral kinematics were measured in vivo in controls and in patients with two different types of total knee implants (Genesis II and Journey, both manufactured by Smith & Nephew Orthopedics, Inc.). Patients were imaged with their knees in full extension and in flexion while a compressive load was applied to the foot using an MR-compatible loading device. Knee flexion angle, patellofemoral contact area, contact centroid, medial/lateral patellar tilt, and medial/lateral patellar shift were measured after registering the images from the two different positions. The results suggest that important differences in patellofemoral kinematics may exist among the three groups.

15:06 744. Ultrahigh Magnetic Field Imaging of the Knee Using a Transmit/receive Array Coil Ute Goerke1, Patrick John Bolan1, Can Akgun1, Gregor Adriany1, Carl Snyder1, Pierre-Francois van de Moortele1, Lance DelaBarre1, Noam Harel1, Tommy Vaughan1, Kamil Ugurbil1, 2, Jutta Ellermann 1Radiology/University of Minnesota Medical School, Minneapolis, USA; 2Max-Planck-Institute for Biological Cybernetics, Tuebingen, Germany

Muscoloskeletal (MSK) imaging aims at visualizing small details of anatomical structures, such as the characterization of cartilage degradation by its thickness and molecular composition. The contrast and high SNR attainable in a high-resolution image has therefore the potential of providing better quantification of morphology and pathophysiological changes. Initial results demonstrate that high resolution in knee imaging can be achieved taking advantage of the gain in SNR at ultrahigh 7 T. Examples obtained with a dedicated transmit-receive radiofrequency coil driven by a multi-channel are shown. This setup permits B1-shimming to compensate for B1-inhomogeneity often observed at ultrahigh magnetic fields.

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15:18 745. A New Approach for High Resolution MRI of the Knee at 3T – Evaluation of a Moderately T2-Weighted 3D-TSE-Fs (SPACE) Sequence Mike Notohamiprodjo1, Annie Horng, Jose Garcia del Olmo Raya, Wolfgang Horger, Jaeseok Park, Christoph Trumm, Maximilian Reiser, Christian Glaser 1University Hospitals Munich, Munich, Germany

The purpose of this study was to evaluate a moderately T2-weighted 3D-TSE-fs-sequence (SPACE) for high-resolved MRI of the knee at 3T. Ten volunteers were examined. An isotropic (resolution 0.53mm3) SPACE was acquired and reformatted into axial, sagittal and coronal sections of 0.5mm, 1mm and 2mm slice thickness (SPACE0.5mm, SPACE1mm, SPACE2mm). As reference standard 2D-TSE-fs-sequences were used. SPACE1mm yields comparable SNR to 2D-TSE-fs and appears, despite lower CNR, superior in depicting relevant small ligamentous and meniscal structures. Our preliminary results suggest that free isotropic reconstructions of SPACE could become a valuable tool in diagnostic work-up of the knee.

HANDS-ON WORKSHOP 2 (REPEAT) Body and Cardiovascular Protocol Optimization Philips Medical Systems Room 709 13:30 – 15:30

Siemens Medical Solutions Room 711 13:30 – 15:30

MR Physics and Techniques for Clinicians Room 801 A/B 16:00 - 18:00 Chairs: Frank R. Korosec and Joseph C. McGowan

Educational Objectives: Upon completion of this course, participants should be able to:

• Define and describe the fundamental principles of MR imaging, including the definition of spin magnetization, the Larmor relationship, relaxation phenomena, and the process of using the spin magnetization to produce an image;

• Explain imaging pulse sequences based upon spin and gradient echoes, including fast spin echo and echo planar techniques; • Design MR imaging protocols for diagnostic applications considering image contrast, spatial resolution, acquisition time, signal-to-noise ratio,

and artifacts; and • Describe the principles of parallel imaging, fat and water imaging, and diffusion imaging.

16:00 Diffusion Imaging Christian Beaulieu 16:40 Fat and Water Imaging Scott B. Reeder 17:20 Cardiac MRI Bob S. Hu

Resting State Fluctuations: Human & Animal Room 718 A 16:00-18:00 Chairs: Ewald V. Moser and Scott J. Peltier

16:00 746. A Resting State Network in the Basal Ganglia Simon Robinson1, Nicola Soldati1, Gianpaolo Basso1, Uta Sailer2, Jorge Jovicich1, Lorenzo Bruzzone, Ilse Kryspin Exner2, Herbert Bauer2, Ewald Moser3 1University of Trento, Trento, Italy; 2University of Vienna, Vienna, Austria; 3Medical University of Vienna, Vienna, Austria

Approximately 10 Resting State Networks (RSNs) of the human brain have been discovered over the past decade, changing our understanding of brain function. Using high temporal resolution EPI, a large number of subjects and group Independent Component Analysis, we uncover a previously unreported network in the basal ganglia; reproducible across subjects and runs. Using a novel analysis of component time course features, we demonstrate that this network clusters with other RSNs rather than physiological artifacts. This finding opens the way for research into possible disturbances of network in basal ganglia pathologies such as Parkinson’s disease.

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16:12 747. Spontaneous Activity in the Visual Cortex Persists During Visual Stimulation: A 7T Study Marta Bianciardi1, Masaki Fukunaga, Peter van Gelderen, Silvina Horovitz, Jacco de Zwart, Jeff Duyn 1National Institutes of Health, Bethesda, USA

The aim of the present study is to investigate whether spontaneous fluctuations in the visual cortex are modulated by visual stimulation. With regard to spontaneous activity in other cerebral regions, previous works showed that both the default mode and the sensory-motor network continue during a wide range of tasks, being respectively modulated/unperturbed by stimulation. The result of our study is that also during visual stimulation, spontaneous and evoked activity overlap in the visual cortex at a 1.25mm in plane resolution. Nevertheless, we show that spontaneous activity during fixation with/without stimulation is reduced with respect to the eyes closed condition.

16:24 748. Language Lateralization is Correlated with Resting-State Connectivity Within the Inferior Frontal Gyri Jolyn N A D'Andrea1, Bradley G. Goodyear1 1University of Calgary, Calgary, Canada

In general, language is lateralized to the inferior frontal gyrus (IFG) of the left hemisphere; however, individual differences in lateralization due to handedness, gender, or pathology, may be associated with individual differences in resting-state connectivity within the IFGs of the two hemispheres. Our results demonstrate, using fMRI, a linear relationship between the degree of lateralization of activity during a verb generation task and inter-hemispheric connectivity within the IFGs, suggesting subjects that are left lateralized for language have stronger inter-hemispheric connections. Connectivity may be a potential alternative for understanding language dysfunction in patients who cannot perform language tasks well.

16:36 749. Investigating Motor Plasticity Using Resting State FMRI and SEM Liangsuo Ma1, Binquan Wang, Donald A. Robin, Peter Fox, Jinhu Xiong1 1University of Iowa, Iowa City, USA

We explored changes in regional activity and inter-regional connectivity in the motor system resting state network (RSN). Subjects were trained to perform a finger movement task for 4 weeks. Three sets of resting state fMRI images were acquired every two weeks. Structural equation modeling (SEM) was used quantify the inter-regional connectivity. We constructed and tested one SEM model. We observed significant changes in both regional activities and inter-regional connectivity in the motor system RSN. The changes in regional activity may reflect altered processing load during different phases of motor learning. Resting state inter-regional connectivity is likely associated with memory consolidation.

16:48 750. Spatial Extent of Task-Induced FMRI-BOLD Response After Hemodynamic Scaling Using Resting State Fluctuations Sridhar S. Kannurpatti1, Bharat B. Biswal1 1UMDNJ-New Jersey Medical School, Newark, New Jersey, USA

Variation in activation-induced fMRI-BOLD response across subjects can depend on their vascular sensitivity. Scaling of fMRI-BOLD response from the vascular sensitivity information contained in the task response signal itself or during resting conditions would be ideal to avoid scaling bias and subject compliance issues during the performance of a hypercapnic task traditionally used for hemodynamic scaling. We test the hypothesis that resting state physiological fluctuation amplitude (RSFA) indicates cerebral vascular reactivity in response to CO2 variation or hypercapnia and can be used as a hemodynamic scaling parameter to minimize intra and inter-subject variations in neural activation-induced fMRI response.

17:00 751. Caffeine Reduces Resting-State Functional Connectivity in the Motor Cortex Anna Leigh Rack-Gomer1, Joy Liau1, Joanna Perthen1, Thomas T. Liu1 1University of California San Diego, La Jolla, California , USA

Functional connectivity maps based on the spatial correlation of resting-state fluctuations in the blood oxygenation level-dependent (BOLD) signal are finding increasing use in applications such as the localization of functional regions, disease diagnosis, and enhanced understanding of information processing strategies employed by the brain. However, the basic mechanisms underlying the correlation in low-frequency BOLD fluctuations are not entirely understood. In this study we show that caffeine-induced vasoconstriction leads to a significant decrease in resting-state functional connectivity.

17:12 752. Comparison of Spontaneous Electrophysiological and FMRI Fluctuations During Rest in Rat Brain Cortex Young Ro Kim1, Bharat B. Biswal, Bruce R. Rosen 1Athinoula Martinos Center for Biomedical Imaging/ Massachusetts General Hospital, Charlestown, Massachusetts, USA

Resting state fMRI has been used to demonstrate that the spontaneous hemodynamic resting state fluctuations (RSF) are spatially synchronous among the functionally related brain regions (e.g., bilateral sensorimotor cortex). This finding has been interpreted as evidence of neural connectivity between discrete brain regions. Despite these advances, the relevance of RSF to overall neural activity and functional connectivity remains unclear. In this study, we plan to use electrophysiological measurements to detect the presence of resting state electro-cellular activity, so as to provide a basis for understanding whether these resting state fluctuations are derived from synchronous neuronal modulation.

17:24 753. Electrophysiological Investigation of the Basis of the Resting-State FMRI Signal Hanbing Lu1, Yantao Zuo1, Hong Gu1, James S. Waltz2, Wang Zhan1, Clara A. Scholl1, William Rea1, Yihong Yang1, Elliot A. Stein1 1NIH, Baltimore, Maryland, USA; 2University of Maryland School of Medicine, Baltimore, Maryland, USA

The neural mechanism of synchronized low frequency spontaneous fluctuations of the fMRI signal remains largely unknown. In the present study, electrophysiological recordings and resting-state fMRI measurements were conducted in á-chloralose anesthetized rats. Region-specific, anesthetic dose-dependent resting-state functional connectivity was detected in bilateral primary somatosensory cortex (S1FL) of the resting brain. Cortical electroencephalographic (EEG) signal was recorded from bilateral S1FL; a visual cortex locus served as a control site. Results demonstrate that the power coherence in low frequency bands, particularly the delta band, correlates with the resting-state fMRI signal.

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17:36 754. Effect of Propofol on Thalamocortical Connection: A High-Field MR Study of Functional Connectivity on Rats Ye Tu1, 2, Tian Yu1, Xiao-Yun Fu1, 2, Peng Xie1, 2, Su Lui2, Ti-Jiang Zhang2, Xiao-Qi Huang2, Hua-Fu Chen3, Qi-Yong Gong2 1Zunyi Medical College, Zunyi, People's Republic of China; 2Huaxi MR Research Center(HMRRC), Huaxi Hospital, Sichuan University, Chengdu, People's Republic of China; 3School of Science and Technology, University of Electronic Science and Technology, Chengdu, People's Republic of China

The mechanism of anesthesia, a state of profound central nervous system suppression is still poorly understood. One interesting question concerns the alteration of neural network under anesthesia.We examined the functional connectivity of the thalamus on rats at different concentration of propofol. Our functional connectivity analysis revealed propofol induced anesthesia disrupted functional interactions within thalamocortical neural networks. Combining regional cerebral blood flow (rCBF) with functional connectivity in future study will provide further insight into the mechanism of anesthesia.

17:48 755. Tightly Coupled Spontaneous EEG and CBF Signals in the Anesthetized Rat Brain Xiao Liu1, 2, Xiao-Hong Zhu1, Yi Zhang1, Wei Chen1 1University of Minnesota, Minneapolis, Minnesota, USA

The present study is to study the neurovascular coupling in the anesthetized rat brain by examining the simultaneously-recorded EEG and CBF signals. Strong temporal correlation was found between them, indicating a tight neurovascular coupling between CBF fluctuation and spontaneous neuronal activity in the resting brain. We also found strong temporal correlations between the left- and right-hemispheric somatosensory cortices for both EEG and CBF signals, which could be linked to the resting-state coherent BOLD fluctuations recently observed in human and animal brains. Therefore, our results may provide supports for the neural origin of the resting coherent BOLD fluctuations phenomenon.

Diffusion Acquisition Room 718 B 16:00-18:00 Chairs: Chunlei Liu and Claudia A. M. Wheeler-Kingshot

16:00 756. Parallel Imaging Method for Split-Blade PROPELLER DWI Donglai Huo1, Zhiqiang Li2, Eric Aboussouan1, John P. Karis3, James G. Pipe1 1Barrow Neurological Institute, Phoenix, Arizona , USA; 2GE Healthcare, Waukesha, Wisconsin, USA; 3Southwest Neuro-Imaging, Phoenix, Arizona , USA

PROPELLER and Turbo-PROP DWI have shown advantages over traditional EPI DWI with high resolution, benign behavior of motion artifacts, and robustness to off-resonance. A split-blade approach is often applied to meet the non-CPMG conditions but makes PROPELLER less robust to motion. In order to widen the PROPELLER blade and reduce motion artifact, we implemented a “Mutual-Calibration” parallel imaging method, in which even and odd echoes are used as calibration data for each other. There is no motion between calibration and reconstruction data, and no additional ACS data are required.

16:12 757. GRAPPA-Accelerated Readout-Segmented EPI for High Resolution Diffusion Imaging Samantha J. Holdsworth1, Stefan Skare1, Rexford D. Newbould1, Anders Nordell2, Roland Bammer1 1Stanford University, Palo Alto, California , USA; 2Karolinska University Hospital, Stockholm, Sweden

Readout mosaic segmentation (RS-EPI) has been suggested as an alternative approach to EPI for high resolution diffusion-weighted imaging (DWI) with minimal geometric distortions. In this abstract, peripherally cardiac gated and non-gated RS-EPI-DW images are acquired with the use of parallel imaging. The methods used to phase correct and reconstruct the partial Fourier GRAPPA-accelerated RS-EPI-DW data are described. It is shown that patient handling can be simplified with the use of non-gated acquisitions and minimally-overlapping blinds. The efficient acquisition of high resolution RS-EPI images makes this sampling strategy a useful alternative to other navigated methods used for DW imaging.

16:24 758. High-Resolution Diffusion Tensor Imaging at 3T with Radial-FSE Joelle E. Sarlls1, Carlo Pierpaoli1 1National Institutes of Health, Bethesda, Maryland, USA

We developed a diffusion-weighted radial-FSE sequence that is insensitive to magnetic field inhomogeneity that can produce very high-resolution, undistorted images suitable for DTI mapping at 3T. This was accomplished by implementing a combined strategy of a mixed-CPMG phase cycling scheme, to mitigate the violation of the CPMG condition for FSE sequences with a diffusion preparation, and a wider refocusing than excitation slice, to mitigate the lack of B1-homogeneity at higher fields. DTI data acquired with the modified radial-FSE sequence provides undistorted DTI maps, which reveal anatomical details that are currently impossible to image with single-shot EPI.

16:36 759. A Navigated Non-CPMG Turbo Spin Echo Pulse Sequence for High Resolution Diffusion Imaging Yongquan Ye1, 2, Yan Zhuo1, 2, Jing An, 23, Xiaohong Joe Zhou4 1Institute of Biophysics, and Graduate University, Chinese Academy of Sciences, Beijing, People's Republic of China; 2Beijing MRI Center for Brain Research, Beijing, People's Republic of China; 3Siemens Mindit Magnetic Resonance Ltd, Shenzhen, People's Republic of China; 4Univ. of Illinois Medical Center, Chicago, Illinois, USA

Recent studies have shown that diffusion-weighted multi-shot turbo spin echo (DW-msTSE) sequences can effectively overcome the limitations imposed by single-shot EPI techniques. Two of the major challenges confronting DW-msTSE include (a) motion sensitivity and (b) violation of the CPMG conditions. We have developed a non-CPMG DW-msTSE sequence to address both problems. Motion sensitivity was reduced by a 2D navigator. The issue with CPMG violation was addressed by a variable crusher gradient scheme that eliminated stimulated echoes from the signal pathways. The DW-msTSE sequence has produced high-resolution, artifact-free diffusion images from both phantoms and healthy human volunteers.

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16:48 760. High-Resolution Axial DWI of the Spinal Cord with Reduced-FOV Single-Shot EPI Emine Ulku Saritas1, Charles H. Cunningham2, Jin Hyung Lee1, Eric T. Han3, Dwight G. Nishimura1 1Stanford University, Stanford, California , USA; 2University of Toronto, Toronto, Canada; 3GE Health Care Global Applied Science Laboratory, Menlo Park, California , USA

Axial in vivo DWI of the spinal cord requires high spatial resolution, due to the small cross-sectional size of the spinal cord. This is very challenging, considering the sources of motion around the spinal cord and the highly inhomogeneous magnetic environment of the spine. Here, we achieve high-resolution axial in vivo ss-DWEPI images by reducing the FOV in the phase-encode direction with a 2D echo-planar RF excitation pulse. This excitation scheme is compatible with multi-slice imaging, and furthermore suppresses the signal from fat with the incorporation of a 180o refocusing pulse.

17:00 761. Parallel Line Scan Diffusion Imaging Renxin Chu1, Bruno Madore1, Lawrence P. Panych1, Stephan Maier1 1Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA

Line scan diffusion imaging (LSDI) allows for considerable robustness against motion without artifacts due to phase wrapping. Combing LSDI and parallel imaging techniques, we propose a novel parallel line scan diffusion imaging (pLSDI) technique with a multiple slice acquisition scheme. The prominent advantage of pLSDI is not only its accelerated acquisitions for LSDI, but the fact that this can be done at essentially no cost in SNR. Phantom and human brain imaging were carried out to test the technique. Our proposed pLSDI approach allows signal separation without phase encoding, while maintaining motion robustness and avoiding additional chemical shift and susceptibility artifacts. The addition of parallel imaging to line-scan imaging accelerates the acquisition with at no losing SNR.

17:12 762. Diffusion at Short Time Scales: Q-Space Imaging with Chirped Gradient Waveforms Andrew JM Kiruluta1, 2, Isam Abu Qasmieh3 1Harvard University, Cambridge, Massachusetts, USA; 2Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, USA; 3university of massachusetts Lowell, Lowell, Massachusetts, USA

The practical limitations imposed by the requirement for delta function type diffusion sensitizing gradients in q-space imaging of diffusing spins, can be relaxed if these impulse gradients are replaced with chirped waveform gradient in a Chirp Gradient Spin Echo (CGSE) experiment. In this abstract, chirped diffusion sensitizing gradients are analytically and through numerical simulations and experiments, shown to yield a practical alternative that asymptotically approaches that using delta functions in a q-space experiment.

17:24 763. Observation of Microscopic Diffusion Anisotropy in the Spinal Cord Using Double-Pulsed Gradient Spin Echo MRI Michal E. Komlosh1, Martin J. Lizak2, Ferenc Horkay3, Raisa Z. Freidlin4, Peter J. Basser3 1NICHD,NIH, Bethesda, USA; 2NINDS,NIH, Bethesda, Maryland, USA; 3NICHD,NIH, Bethesda, Maryland, USA; 4CBEL,CIT,NIH, Bethesda, Maryland, USA

A double Pulsed Gradient Spin Echo (d-PGSE) filtered MRI sequence was propose to detect local anisotropy in heterogeneous systems. The sequence was first tested on a macroscopically isotropic, microscopically anisotropic “gray matter” phantom, which consists of randomly immersed tubes filled with water, and then applied on a formalin fixed spinal cord. Local anisotropy was observed in both the gray matter phantom and spinal cord specimen using b-values readily achievable on clinical scanners. This finding suggests a potential use of this contrast mechanism.

17:36 764. Double Wave Vector Diffusion Weighting in the Human Corticospinal Tract in Vivo Martin A. Koch1, Jürgen Finsterbusch1 1University Medical Center Hamburg-Eppendorf, Hamburg, Germany

Diffusion weighting with two successive gradient pulse pairs of different direction can be used to derive information about tissue structure that is not easily available otherwise, e.g. cell size and shape. To date the underlying effect has only been demonstrated in vitro. The in vivo results presented here support the notion that the predicted effect can be observed in human brain tissue in vivo on a clinical MR system.

17:48 765. Magnetization Transfer Prepared Diffusion Tensor Imaging Alexandru Vlad Avram1, Arnaud Guidon1, Allen W. Song1 1Duke University, Durham, North Carolina, USA

Traditional DTI methods usually do not offer specific selectivity regarding the origin of the connectivity changes. In this report, we incorporate a magnetization preparation pulse into the conventional diffusion tensor imaging to provide additional selectivity to proton pools modulated by the macromolecules. It is shown that changes in diffusion tensor can be robustly detected that are suggestive of their origin in macromolecular structures such as myelin. It is hoped that this additional selectivity using DTI can be used to investigate the pathological processes (e.g demyelination) in many white matter diseases (e.g. multiple sclerosis, ALS, autism).

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Metabolic & Functional Assessment of Cancer: Clinical Studies Room 714 A/B 16:00-18:00 Chairs: Arend Heerschap and Jason Koutcher

16:00 766. An International, Multi-Institutional Trial of DCE-MRI in Children Treated for Osteosarcoma Wilburn E. Reddick1, John O. Glass1, Catherine A. Billups1, Fred A. Hoffer1, Jesse J. Jenkins1, Juan Quintana2, Milena Villarroel2, Lori Luchtman-Jones3, Najat C. Daw1 1St. Jude Children's Research Hospital, Memphis, Tennessee, USA; 2Luis Calvo Mackenna Hospital, Santiago, Chile; 3Washington University Medical School, St. Louis, Missouri, USA

The current study prospectively evaluated the use of a two-compartment pharmacokinetic model of DCE-MRI to non-invasively evaluate tumor response to neoadjuvant chemotherapy in children treated on a single phase II trial at three institutions (2 US and 1 Chile). DCE-MRI was performed at baseline, week 9, and week 12 of preoperative chemotherapy prior to definitive surgery. Histological assessment of tumor response was determined from en bloc resections. Decreased Ktrans and ve at week 9 relative to presentation was significantly associated with good histologic response to preoperative chemotherapy. Patients with higher Ktrans and ve at presentation were more likely to have good histological response. DCE-MRI is a non-invasive method that can be feasibly used to assess tumor response to neoadjuvant chemotherapy in OS even between institutions in an international setting.

16:12 767. Dynamic Contrast Enhanced MRI as a Predictor of Long Term Outcome in Pediatric Bone Tumors Jason A. Koutcher1, Ya Wang1, Howard T. Thaler1, Paul Meyers1, Leonard H. Wexler1, Jonathan P. Dyke2, David M. Panicek1, Lawrence H. Schwartz1, Maayan E. Korenblit1, Wei Huang1 1Memorial Sloan Kettering Cancer Center, New York, New York, USA; 2Weill-Cornell Medical College, New York, New York, USA

Bone sarcomas are among the most common pediatric tumors. The most useful prognostic marker has been percent necrosis at time of surgery post chemotherapy – patients with > 90% necrosis have a better prognosis. Using DCE-MRI, we have found the combination of measuring ve (interstitial volume fraction) and pathological necrosis is a highly significant predictor of long term survival in a group of 25 patients followed for up to 9 years (p<0.002) and is superior to percent necrosis alone which has only borderline statistical significance. Only one of the 25 patients was misclassified by this method.

16:24 768. Treatment Response Predictor Using 31P MRS for CHOP and R-CHOP Therapy in Diffuse Large B-Cell Lymphoma Fernando Arias-Mendoza1, Geoffrey S. Payne2, Kristen Zakian3, Marion Stubbs4, Jaime G. Cruz-Lobo1, A J. Schwarz2, Amita Dave3, Franklyn Howe5, N R. Maisey2, D Cunningham2, H Poptani6, M R. Smith7, O A. O'Connor1, R Pettengell5, M O. Leach2, J A. Koutcher3, J R. Griffiths4, A Heerschap Heerschap8, J D. Glickson6 1Columbia University, New York, New York, USA; 2Royal Marsden Hospital, London, UK; 3Memorial Sloan Kettering Cancer Center, New York, New York, USA; 4Cambridge University, Cambridge, UK; 5St. George's Hospital, London, UK; 6University of Pennsylvania, Philadelphia, Pennsylvania, USA; 7Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA; 8Radboud University Nijmegen Medical Center, Nijmegen, Netherlands

Our ongoing international multi-institutional research program has demonstrated that the sum of the integrated 31P-MR resonances of phosphoethanolamine plus phosphocholine [Etn-P + Cho-P] normalized by the total nucleotide triphosphates (NTP) acquired prior to treatment initialization can predict treatment failure and drug-free survival in various forms of lymphomas. To make our results diagnosis- and treatment- specific, patients with diffuse large B-cell lymphomas (DLBCL) that were treated with CHOP or R-CHOP were studied. As in our previous reports, we show here that the pre-treatment [Etn-P + Cho-P]/NTP ratio predicts long-term failure to treatment and drug-free survival in these set of patients.

16:36 769. Prediction of Response to Chemo/radiation Therapy of Squamous Cell Carcinomas of the Head and Neck by 1H MRS Studies of Choline Sungheon Kim1, Sanjeev Chawla1, Laurie A. Loevner1, Harry Quon1, Eric J. Sherman1, Gregory S. Weinstein1, Harish Poptani1 1University of Pennsylvania, Philadelphia, USA

In this study 1H MRS was performed in the metastatic cervical lymph nodes of squamous cell carcinomas of the head and neck (HNSCC) to assess the potential of choline as a biomarker for treatment response. Single-voxel 1H MR spectroscopy was performed in 32 patients who were treatment naïve. A negative correlation was observed between tCho and residual tumor volume at the end of treatment suggesting that higher pre-treatment tCho values indicate better treatment response. These studies indicate that pre-treatment choline levels can be used as a marker for prediction of treatment response in HNSCC.

16:48 770. Predicting Final Pathological Response to Neoadjuvant Chemotherapy in Breast Cancer Using Quantitative MR Spectroscopy Using Internal Reference Method at 1.5T Hyeon-Man Baek1, Jeon-Hor Chen, 2, Shadfar Bahri, Rita S. Mehta, Orhan Nalcioglu, Min-Ying Su 1 University of California-Irvine, Irvine, California , USA; 2China Medical University Hospital, Taichung 404, Taiwan

The changes of choline and tumor size in 35 patients receiving neoadjuvant chemotherapy were analyzed. Depending on the final pathological findings, patients were separated into pathologic complete response (pCR) vs. residual disease (non-pCR) groups. In F/U-1 after 2cycles AC, the median change of Cho and tumor size was -62% and -17%, respectively in the pCR group, and was -36% and -15% in the non-pCR group. In F/U-2, all pCR patients had non-detectable Cho. The changes of Cho were greater than the size changes, and higher in pCR than in non-pCR group. Therefore, its role for response prediction warrants further investigation.

17:00 771. Variation of Breast Vascular Maps at Dynamic Contrast-Enhanced MR Imaging Before and After Neoadjuvant Chemotherapy of Locally Advanced Breast Cancer Laura Martincich1, Ilaria Bertotto1, Alfonso Fausto2, Filippo Montemurro1, Daniele Regge1, Francesco Sardanelli2, 3 1Institute for Cancer Research and Treatment, Candiolo, Italy; 2Policlinico S.Donato, S. Donato Milanese, Italy; 3University of Milan, Milan, Italy

In vivo effects of NCT on tumor vascularity are not exhaustively studied by MRI. The evaluation of breast vascularity by DCE-MRI may have a role in the evaluation of tumor response, identifying patients who better benefit from therapy.

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17:12 772. Dynamic Contrast Enhanced MRI of Solid Tumors and Healthy Tissue During Treatment with NGR-TNF, a Novel Vascular Targeting Agent Hanneke W.M. van Laarhoven1, Jacques A. van Asten1, Ingrid Desar1, Gian Paolo Rizzardi2, Claudio Bordignon2, Cornelis Punt1, Carla van Herpen1, Arend Heerschap1 1Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands; 2Molmed, Milan, Italy

Targeted delivery to the tumor of picogram doses of TNF-alpha can be achieved by coupling TNF-alpha with CNGRC (NGR-TNF), a peptide that specifically targets tumor neovasculature. The aim of this study was to asses the effect of NGR-TNF on solid tumors and healthy liver tissue with dynamic contrast enhanced MRI (DCE-MRI) during a phase I trial with NGR-TNF. Two hours after treatment we observed a significant decrease in kep and Ktrans in solid tumors compared to baseline, but not in healthy liver tissue. This suggests a tumor-specific anti-vascular effect of NGR-TNF.

17:24 773. DCE-MRI Demonstration of Antivascular Effects of Combretastatin A4 Phosphate (CA4P) Given in Combination with Bevacizumab to Human Subjects with Advanced Solid Tumours Anwar R. Padhani1, Dow-Mu Koh2, NJ Jane Taylor1, James J. Stirling1, David J. Collins2, Gordon J. Rustin1, Adrian Harris3, R Sinha, Jane Boxall1, J Smythe3, N Fisher4, Hillori Connors5, Ian Judson, Paul Nathan1 1Mount Vernon Cancer Centre, Northwood, UK; 2Institute of Cancer Research, Sutton, UK; 3John Radcliffe Hospital, Oxford, UK; 4National Blood Transfusion Service, Oxford, UK; 5Oxigene Inc., Waltham, Massachusetts, USA

In this study we document reversible tumour vascular shutdown following the first administration of the vascular disruptive agent (CA4P) and show failure of recovery of tumour vasculature when CA4P is given with the anti-VEGF antibody bevacizumab. Marked heterogeneity in individual lesion responses were seen but cohort analysis convincingly shows failure of tumour vasculature to recover when CA4P is given with bevacizumab. This is the first mechanistic demonstration in humans of increased anti-vascular action of CA4P and bevacizumab using DCE-MRI.

17:36 774. MR Perfusions Imaging of Anti Angiogenic (Bevacizumab) Treatment in Patients with Recurrent High Grade Gliomas Bob Lei Hou1, Sasan Karimi2, Lauren E. Abrey2, Andrei I. Holodny2, Philip H. Gutin2 1MSKCC, New York City, USA; 2MSKCC, New York City, New York, USA

Anti-angiogenic therapy using bevacizumab (Avastin) affects abnormal neovascularity of high grade primary brain tumors. We used DCE and DSE perfusion techniques on 9 patients with recurrent high grade gliomas before and after the first cycle of bevacizumab. Mean bolus wash-in slopes, Ktrans, fBV, and rCBV ratios for the 9 patients decreased respectively from 2.07+/-1.77 to 0.84+/-0.85, 1.86 +/-0.80 to 1.26+/-0.21, 1.83 +/-0.85 to 1.36+/-0.71, and 1.92+/-0.99 to 1.20+/-0.28. Ktrans ratio (p=0.043) and bolus wash-in slopes (p=0.015) before and after treatment were significantly different suggesting the bolus wash-in slope from DCE perfusion is the most sensitive parameter for tumor vessel changes.

17:48 775. Apparent Diffusion Coefficients Show Good Reproducibility But Heterogeneous Change in Response to Treatment with Combrestation A4 Phosphate (CA4P) and Bevacizumab in Patients with Solid Abdominal and Pelvic Tumours Dow-Mu Koh1, 2, Anwar Padhani3, Matthew Blackledge4, Ben Wilton4, David J. Collins4, Toni Wallace2, N J. Taylor3, James J. Stirling3, Rajesh Sinha2, Hillori Connors5, Martin O. Leach4, Ian Judson4, Paul Nathan6 1Institute of Cancer Research, Sutton, UK; 2Royal Marsden Hospital, Sutton, UK; 3Mount Vernon Hospital, UK; 4Institute of Cancer Research, Sutton, UK; 5Oxigene Inc, USA; 6Mount Veron Hospital, UK

The aims of this study were to determine the ADC measurement variability in a two centre clinical trial, and to track ADC changes in response to the administration of the vascular disrupting drug Combrestatin A4 phosphate (CA4P) and the anti-VEGF antibody bevacizumab. We found that ADC showed excellent reproducibility. However, mean ADC values proved to be insensitive to treatment related effects in our study and bio-informatics based approaches to data analysis should be developed.

Exploring the Frontiers of MRS Methodology Room 716 A/B 16:00-18:00 Chairs: Robin A. de Graaf and Tom W. J. Scheenen

16:00 776. Enhanced Sensitivity for Multidimensional High-Resolution Magic-Angle-Spinning 1H-MR Spectroscopy Ovidiu Cristian Andronesi1, 2, Dionyssios Mintzopoulos1, 2, Jochem Struppe3, Peter McLaren Black4, Aria A. Tzika1, 2 1Massachusetts General Hospital and Shriners Burn Hospital, Harvard Medical School, Boston, Massachusetts, USA; 2Athinoula A. Martinos Center for Biomedical Imaging, Boston, Massachusetts, USA; 3Bruker BioSpin Corp, Billerica, Massachusetts, USA; 4Brigham and Women's Hospital, Boston, Massachusetts, USA

We present a solid-state NMR method that maximizes the advantages of HRMAS 1H-MRS applied to intact tissue biopsies. Liquid-state NMR sequences, currently employed, may reintroduce, unintentionally, residual anisotropic interactions. Simulations and experiments on brain biopsies of an adiabatic TOBSY (TOtal through Bond correlation SpectroscopY) solid-state sequence for two-dimensional 1H-1H scalar-coupling mixing indicate a significant SNR gain (>100% theoretically and 20-50% experimentally) relative to its liquid-state analogue TOCSY (TOtal Correlation SpectroscopY). This is the first demonstration of such a concept for HRMAS metabolic profiling that can help in detecting new macromolecular biomarkers (proteins) and reducing sample degradation for further analysis (genomics).

16:12 777. Downfield Spectra at Ultrahigh Field Anke Henning1, Alex Fuchs1, Chris Boesch2, Peter Boesiger1, Roland Kreis2 1University and ETH Zurich, Zurich, Switzerland; 2University Berne, Berne, Switzerland

The advantages of very high fields for MRS in humans (increased SNR and chemical shift dispersion) have been exploited for the upfield part of the human cerebral 1H spectrum but not for the downfield part, which is still poorly characterized. In this work, 7T downfield spectra from human periventricular white matter are presented, compared to corresponding spectra recorded at lower field strength and characterized regarding contributing metabolites and relaxation behaviour as well as in view of chemical exchange with (suppressed) water. Communalities, but also substantial differences were found when compared to equivalent spectra obtained at lower fields.

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16:24 778. Lactate Metabolism in Human Brain Measured by Dynamic 13C MRS Fawzi Boumezbeur1, 2, Kitt Falk Petersen2, Graeme F. Mason1, Robin A. de Graaf1, Gary W. Cline2, Kevin L. Behar1, Gerald I. Shulman, 23, Douglas L. Rothman1 1Magnetic Resonance Research Center, Yale University, New Haven, USA; 2Yale School of Medicine, New Haven, USA; 3Howard Hughes Medical Institute, Yale School of Medicine, New Haven, USA

Previous studies have shown that lactate is a potential fuel for brain energy metabolism. To elucidate lactate transport kinetics (VMAX, KT) and estimate its net contribution to human brain energy metabolism in vivo (CMRlac), we used localized 13C MRS and infusions of [3-13C]lactate. With a plasma concentration being in the 0.8-2.8 mmol.L-1 range, we have estimated VMAX=0.29µmol.g-1.min-1 and KT=4.3µmol.g-1, CMRlac being found to be modest in normal condition. The same approach could be used to investigate in vivo the role of lactate metabolism in sustaining brain function in conditions such as fasting, hypoglycemia, hypoxia/ischemia or neurodegenerative processes.

16:36 779. Measuring NAA Synthesis in Vivo Using Proton MRS Su Xu1, Jun Yang1, Jun Shen1 1NIMH, Bethesda, Maryland, USA

Here we demonstrate that NAA synthesis can be measured using proton MRS during infusion of uniformly 13C-labeled glucose without using the 13C channel. The rate of 13C-label incorporation into the acetyl group of NAA was measured in the rat brains in vivo using localized long echo-time proton MRS by detecting the 13C satellites of the main NAA methyl proton signal at 2.02 ppm. The NAA synthesis rate measured by this method is ~19 μmol/g h.

16:48 780. Efficient 1H to 31P Polarization Transfer in the Human Brain on a Clinical 3T MR System with a Single RF Transmit Channel Dennis Klomp1, Jannie Wijnen1, Tom Scheenen1, Arend Heerschap1 1Radboud University Nijmegen, Medical Center, Nijmegen, Netherlands

(Glycerol)phosphocholine and (glycerol)phosphoetanolamine can be used as early markers for response to treatment, detectable by 31P MRS. A potential sensitivity enhancement of γ 1H/γ 31P can be obtained using 1H to 31P polarization transfer techniques. However, due to J couplings between 31P and 1H that have similar magnitudes for homonuclear J couplings in these metabolites, the enhancement is conventionally less than 50%. We applied chemical shift selective refocusing pulses for full 1H to 31P polarization transfer for these metabolites, have integrated the method in a clinical broadband MR system, and quantified the sensitivity gain using measured T1 and T2 values.

17:00 781. Ultrafast 2D Spectroscopy for in Vivo Applications on a 7T Whole Body Scanner Rafal Panek1, Walter Kockenberger1 1University of Nottingham, Nottingham, UK

In vivo 1H NMR spectroscopy is made difficult owing to complex and overcrowded spectra and signal overlap of broadened resonance lines. A powerful strategy to facilitate the assignment of crowded spectra is the use of 2-dimensional spectroscopy. However, these methods suffer from long data acquisition times that makes their use for in vivo applications difficult. Ultrafast gradient assisted single-scan 2D MRS schemes proposed recently have the potential to overcome these limitations but their implementation on whole body scanners is technically challenging. This work demonstrates the first implementation of an ultrafast single-scan approach on a 7T whole body scanner.

17:12 782. Age Dependence of the Downfield Region of Cerebral 1H MR Spectra Roland Kreis1, Karin Zwygart1, Verena Beutler1, Daniela Trapp2, Chris Boesch1, Jean-Marc Nuoffer2 1University Berne, Berne, Switzerland; 2Childrens University Hospital, Berne, Switzerland

The downfield part of the 1H-MR spectrum is still ill-defined, and there is no information on its age-dependence. Thirtyseven healthy subjects (newborn to 48 y) were investigated by 1H-MRS using a protocol focused on the downfield spectrum. Major metabolic differences were found for neonates. Additionally, the NH peak of NAA is shown to still increase up to age 15, while no significant changes were detected for any part of the downfield spectrum from 15 to 50 years. The averaged spectra can now serve as age-dependent norm for determination of phenylalanine in phenylketonuria or for diagnostic MRS in children and neonates.

17:24 783. Safety Evaluation for 1H Decoupled 13C Spectroscopy at 3T in Human Frontal Lobe: SAR Analysis Using Numerical Simulations Shizhe Li1, Shumin Wang1, Jun Shen1 1NIH, Bethesda, Maryland, USA

Past human brain 13C spectroscopy studies were limited to the occipital lobe partially because strong proton decoupling power is required. A recent new strategy has shown that the proton decoupling power can be significantly reduced when [2-13C]glucose was used. This approach provides an opportunity to acquire proton decoupled 13C spectrum from human's frontal lobe. To evaluate the safety of frontal lobe decoupling, we have performed SAR analysis for two coil designs using computer simulations with a human head model. The results show that, using the new strategy approach, one can safely acquire proton decoupled 13C spectroscopy in human's frontal lobe within current safety guidelines.

17:36 784. NMR Measurement of VTCA Correlates with Enzymatic Activity Along the TCA Cycle as Measured by Histochemistry in the Primate Brain Fawzi Boumezbeur1, Laurent Besret2, Julien Valette1, Emmanuel Brouillet2, 3, Martine Guillermier2, 3, Caroline Jan2, 3, Philippe Hantraye2, 3, Gilles Bloch4, Vincent Lebon1, 3 1NeuroSpin, Gif-sur-Yvette, France; 2CNRS URA 2210, Orsay, France; 3MIRCen, Fontenay-aux-Roses, France; 4SHFJ, Orsay, France

For the past years, 13C MRS has been used to explore brain metabolism. Yet, NMR-measured TCA cycle flux (VTCA) remains somewhat controversial. To estimate the ability of MRS to detect changes in enzymatic activity, we have induced a stable inhibition of the succinate dehydrogenase. This inhibition has led to a major decrease of VTCA as measured in vivo (mean -44%, -52% for the sacrificed monkey). Post-mortem measurement of SDH inhibition using in situ histochemistry has led to a remarkably similar estimation (putamen: 48%; caudate: 42%). This comparison supports strongly the validity of in vivo MRS measurement of VTCA.

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17:48 785. Two-Echo Multiple Quantum Chemical Shift Imaging of Ascorbic Acid (Vitamin C) in the Human Brain in Vivo at 3 T In-Young Choi1, 2, Sang-Pil Lee1 1University of Kansas Medical Center, Kansas City, Kansas, USA

A spectral editing method is proposed for measuring ascorbic acid in the human brain in vivo at 3 T. It utilizes the selective multiple quantum filtering method to suppress all overlapping resonances with ascorbic acid in a single scan. A combination of the multiple quantum filtering method and two-echo approach provides a simultaneous measurement of ascorbic acid and singlet signals without increase of scan time. Singlet signals of creatine, choline and NAA are used for reliable quantification of ascorbic acid. This method allows assessment of the distribution of ascorbic acid in the human brain at clinical field strength, 3 T.

Case-Based Teaching IV: Neuroimaging Room 701 A 16:00 - 18:00 Chair: Patricia Ellen Grant

16:00 DWI Beyond Stroke: Case Examples in Metabolic Disorders and Leukodystrophies Zoltan Patay

16:30 Direction Counts: Clinical Cases and Technical Discussion in Tractography Alberto Bizzi

17:00 Perfusion ASL vs. DSC: Do We Need Gadolinium in Clinical Practice? Ronald Wolf

17:30 Case Examples in fMRI: Not Just for Preoperative Localization Keith R. Thulborn

Image Reconstruction Room 701 B 16:00-18:00 Chairs: Craig H. Meyer and Bradley P. Sutton

16:00 786. Image Reconstruction from Ambiguous PatLoc-Encoded MR Data Gerrit Schultz1, Jürgen Hennig1, Maxim Zaitsev1 1University Hospital Freiburg, Freiburg, Germany

We present the first efficient and practical reconstruction algorithm for general non-bijective, curvilinear encoding fields. The algorithm makes use of parallel imaging techniques to resolve the occurring ambiguities. When overlapping coil sensitivities are considered, this can be done by a generalized SENSE-like reconstruction method, where acceleration is determined by the order of ambiguity. Nonlinearities are not treated as perturbations, but as an integral part of the reconstruction procedure. The algorithm is demonstrated for multipolar encoding fields, showing resolution enhancement at the periphery of the imaging region and loss of resolution towards the center, where the fields have a flat profile.

16:12 787. Off-Resonance Effects in Non-Cartesian Parallel Imaging Weitian Chen1, Peng Hu1, Chunlei Liu2, Craig H. Meyer1 1University of Virginia, Charlottesville, Virginia , USA; 2Stanford University, Palo Alto, California , USA

Off-resonance commonly exists in MR systems and can cause image artifacts in a number of MR imaging methods. MR scanning based on non-Cartesian sampling in k-space is sensitive to off-resonance. Off-resonance effects on non-Cartesian parallel imaging are complicated since they not only cause image blurring but can also interact with the unaliasing process. In this abstract, we use spiral scanning as an example to demonstrate off-resonance effects on non-Cartesian parallel imaging.

16:24 788. Fast, Mathematically Exact k-Space Sample Density Compensation for Rotationally Symmetric Interleaved Trajectories, and the SNR-Optimized Reconstruction from Non-Cartesian Samples Dimitris Mitsouras1, Robert V. Mulkern1, 2, Frank J. Rybicki1 1Harvard Medical School & Brigham And Women's Hospital, Boston, Massachusetts, USA; 2Children's Hospital, Boston, Massachusetts, USA

A recently developed exact density compensation method solves a system of equations based on analytic cross-correlations of Fourier basis functions corresponding to the trajectory. Its application to image reconstruction is problematic since the system matrix size is equal to the number of samples (e.g., 65000-by-65000 for 256 image matrix). Here we show that rotationally symmetric interleaved trajectories, such as multi-shot spiral and PROPELLER, lead to a circulant block-Toeplitz system matrix, enabling fast solution within a few seconds. Extensive simulation and experimental results show 10% RMS error reduction concurrently with 28% increase in SNR achieved for a 32-way interleaved spiral trajectory.

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16:36 789. Improved Image Reconstruction for Partial Fourier Gradient-Echo EPI Nan-kuei Chen1, Koichi Oshio2, 3, Lawrence P. Panych2 1Duke University, Durham, North Carolina, USA; 2Brigham and Women's Hospital, Boston, Massachusetts, USA; 3Keio University, Tokyo, Japan

The partial-Fourier EPI enables high-resolution fMRI scan at an optimal echo time. However, the partial-Fourier EPI may be degraded by artifacts that are not usually seen in other types of imaging. Those unique artifacts, to our knowledge, have not yet been systematically evaluated. Here we use k-space energy spectrum analysis to characterize two types of partial-Fourier EPI artifacts. We show that Type 1 artifact cannot be corrected with any post-processing method, and Type 2 artifact can be eliminated with an improved reconstruction method. We further propose a novel algorithm to reconstruct partial-Fourier EPI with minimal Type 2 artifact.

16:48 790. Magnetic Field Monitored Autofocus Deblurring for Improved Non-Cartesian Imaging Florian Wiesinger1, Pekka Sipilae1, 2, Silke Maria Lechner1, 2, Rolf Feodor Schulte1 1GE Global Research, Munich, Germany; 2Munich University of Technology, Munich, Germany

Reliable non-Cartesian imaging requires experienced system tuning, as well as advanced reconstruction schemes incorporating B0 blurring correction. In this work an autofocus reconstruction method is described which achieves automatic B0 deblurring without prior information on the main magnetic field inhomogeneity. In order to also account for gradient field imperfections, magnetic field monitoring has been used to capture the exact encoding information simultaneous to data acquisition. Hence, high-quality spiral images were obtained in the presence of significant DB0 inhomogeneities and gradient field imperfections, without the need for extra system tuning, or calibration interactions.

17:00 791. Fast Conjugate Phase Image Reconstruction Based on a Chebyshev Approximation to Correct for B0 Field Inhomogeneity and Concomitant Gradients Weitian Chen1, Christopher T. Sica1, Craig H. Meyer1 1University of Virginia, Charlottesville, Virginia , USA

Off-resonance can cause image blurring in spiral scanning and variousforms of image degradation in other methods. Off-resonance can becaused by both B0 inhomogeneity and concomitant gradient fields.Previously developed off-resonance correction methods focus on thecorrection of a single source of off-resonance. This work introducesa computationally efficient method of correcting for B0 inhomogeneityand concomitant gradients simultaneously. The method is a fastalternative to conjugate phase reconstruction, with the off-resonancephase term approximated by Chebyshev polynomials. The proposedalgorithm is well suited for semi-automatic off-resonancecorrection, which works well even with an inaccurate or low-resolutionfield map. The proposed algorithm is demonstrated using phantom andin vivo data sets acquired by spiral scanning.

17:12 792. Improved Time Series Reconstruction for Dynamic MRI Uygar Sümbül1, Juan Manuel Santos1, John Mark Pauly1 1Stanford University, Stanford, California , USA

A fast statistical reconstruction algorithm for non-Cartesian dynamic MRI that yields a better temporal response is presented. The method is based on the famous Kalman filter and it provides increased frame rates through a fast algorithm. 4x accelerated reconstructions are presented that outperforms the sliding window reconstruction both in SNR and temporal resolution.

17:24 793. Optimizing K-T BLAST/SENSE Using FOCUSS and RIGR Hong Jung1, Jong Chul Ye1 1Korea Advanced Institute of Science & Technology (KAIST), Guseong-dong Yuseong-gu, Republic of Korea

Recently, compressed sensing has been an active topic in dynamic MR imaging, and a new algorithm called k-t FOCUSS was proposed by employing FOCUSS algorithm to exploit the sparsity of the dynamic cine in x-f domain. Interestingly, k-t BLAST/SENSE algorithm turns out to be an approximation of k-t FOCUSS algorithm. Previously, temporal average was used to initialize these algorithms. However, it introduces the signal nulling artifact. The main contribution of this paper is to show that the signal nulling can be effectively suppressed by incorporating RIGR (Reduced-encoding Imaging by Generalized-series Reconstruction) initialization into k-t FOCUSS iteration. Interestingly, recently proposed SPEAR (Spatiotemporal domain based unaliasing employing sensitivity Encoding and Adaptive Regularization) algorithm turns out to be the first iteration of modified k-t FOCUSS that is optimal from compressed sensing perspective. Experimental result shows that highly accurate dynamic cine can be obtained even from severely down sampled data.

17:36 794. Generalized Reconstruction by Inversion of Coupled Systems (GRICS) Applied to Free-Breathing MRI Freddy Odille1, 2, Pierre-André Vuissoz1, 2, Pierre-Yves Marie3, Jacques Felblinger1, 2 1Nancy University, Nancy, France; 2INSERM ERI 13, Nancy, France; 3University Hospital Nancy, Nancy, France

Correction for arbitrary motion (non rigid or affine) in reconstruction has been demonstrated recently. However, practical implementation is difficult, as a model is required to predict displacement fields at each sample time point. Small motion prediction errors are shown to propagate linearly in that reconstruction algorithm. This leads to reformulating reconstruction as two inverse problems which are coupled: motion compensated reconstruction (knowing motion), and motion model optimization (knowing the solution image). A fixed point multiresolution scheme is described for coupled systems inversion. This framework is shown to allow fully autocalibrated reconstructions, and is validated with free-breathing scans from healthy volunteers.

17:48 795. High-Resolution Pulmonary Perfusion Imaging in Rodents Using a Spatiotemporal Model Sarah Schmitter1, Nilesh N. Mistry, 2, Cornelius Brinegar1, G. Allan Johnson, Zhi-Pei Liang1 1University of Illinois at Urbana-Champaign, Urbana, Illinois, USA; 2Duke University, Durham, North Carolina, USA

Pulmonary perfusion using Gd based contrast agents is an important tool for investigation of vascular pulmonary diseases. Imaging a rodent to study these disease models is challenging due to the high spatiotemporal demands. This work presents a new method for perfusion imaging in rodents using a novel spatiotemporal model. As compared to an existing method using interleaved radial imaging and sliding-window keyhole reconstruction, the technique presented in this work results in a ~6-fold improvement in temporal resolution.

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Molecular MRI Monitoring of Therapy & Disease Room 713 A/B 16:00-18:00 Chairs: Paul Bottomley and Jerry D. Glickson

16:00 796. Thermosensitive Polymer-Modified Liposome as a Multimodal and Multifunctional Carrier for MRI and Optical Imaging: Tumor Detection, Visualization of Triggered Drug Release, and Chemotherapy Ichio Aoki1, Misao Yoneyama1, Jun Hirose2, Yuzuru Minemoto3, Takayoshi Koyama3, Sadahito Aoshima4, Jeff Kershaw1, Kenji Kono2, Yukihito Ishizaka3, Iwao Kanno1 1National Institute of Radiological Sciences, Chiba, Japan; 2Osaka Prefecture University, Osaka, Japan; 3International Medical Center of Japan, Tokyo, Japan; 4Osaka University, Osaka, Japan

A liposomal drug-delivery-system (DDS) will be help to avoid the side effects of chemotherapy by releasing anticancer drug at the tumor site. To improve the liposomal-DDS, we developed a multimodal thermo-sensitive polymer-modified liposomes (MTPL) and added new factors, long-term stability of the liposome in-vivo, passive accumulation in the tumor, and multimodal observation with MRI and optical imaging. The purpose of this study was to investigate whether 1) MRI and optical imaging can visualize MTPL accumulation in the tumor, 2) MTPL allows visualization of the drug-release after being triggered by mild-heating, and 3) MTPL can provide anti-tumor effects after treatment.

16:12 797. Trifluoromisonidazole (TFMISO) as Imaging Agent of Hypoxia in Solid Tumors - An In Vivo 19F MR Study Ellen Ackerstaff1, Khushali Kotedia1, Mihai Coman1, Kristen L. Zakian1, Sean A. Burke1, Sean D. Carlin1, Joseph O'Donoghue1, Clifton C. Ling1, Jason A. Koutcher1 1Memorial Sloan-Kettering Cancer Center, New York, New York, USA

Tumor hypoxia may influence treatment response and outcome. Thus, we investigated the potential of Trifluoromisonidazole (TFMISO) to measure hypoxia in solid tumors by in vivo 19F MRS and MRSI in two animal models of cancer breathing either air or 100% oxygen. Intratumoral TFMISO concentration increased with tumor growth in the MCa tumor model irrespective of amount of oxygen applied. In the R3327-AT model, intratumoral TFMISO levels were only moderately influenced by tumor growth but seemed to decrease in response to breathing of 100% oxygen in tumors below ~600mm3. Our results suggest that TFMISO may be useful for tumor hypoxia imaging by MR.

16:24 798. MRI-Guided Targeting of Magnetic Nanoparticles in an Orthotopic 9L Gliosarcoma Brain Tumor Model Beata Chertok1, Allan E. David1, Bradford A. Moffat2, Brian D. Ross1, Victor C. Yang1 1University of Michigan, Ann Arbor, Michigan, USA; 2University of Melbourne, Melbourne, Australia

This study investigated the utility of MRI to guide the alignment of a brain tumor lesion with magnetic field gradient to improve on specificity of magnetic nanoparticle accumulation within the tumor by an externally applied magnetic field in orthotopic 9L glioma model.

16:36 799. MR Molecular Imaging of Neovasculature May Predict Response to Antiangiogenic Therapy in Animal Cancer Models Anne H. Schmieder1, Patrick M. Winter1, Todd A. Williams1, John S. Allen1, Grace Hu1, Huiying Zhang1, Shelton D. Caruthers1, 2, Samuel A. Wickline1, Gregory M. Lanza1 1Washington University School of Medicine, St Louis, Missouri, USA; 2Philips Medical Systems, Andover, Massachusetts, USA

Noninvasive high-resolution MR molecular imaging can provide a unique tool to characterize and quantify neovasculature in tumors. 3D neovascular mapping in mice implanted with MDA435 tumors revealed sparse neovascularity, which was further decreased with α5β1-targeted but not αvβ3-targeted antiangiogenic treatment. However, MDA435 tumor size was unaffected by either regimen, suggesting that MDA435 xenograft tumor growth has little dependence on angiogenesis, unlike previous results in the rabbit Vx2 model. These data illustrate the prognostic opportunities afforded by noninvasive high-resolution MR molecular imaging that may be clinically relevant in establishing personalized therapy regimens.

16:48 800. In Vivo Intracellular PO2 Measurements of Perfluorocarbon Labeled 9L Glioma Cells Deepak K. Kadayakkara1, Lisa K. Pusateri1, Hongyan Xu1, Jelena M. Janjic1, Eric T. Ahrens1, 2 1Carnegie Mellon University, Pittsburgh, Pennsylvania, USA; 2Pittsburgh NMR Centre for Biomedical Sciences, Pittsburgh, Pennsylvania, USA

In vivo oximetry of tumor tissues by MRI has enormous potential for preclinical evaluation of new therapeutics. Existing 19F relaxometry methods measure the pO2 of the tumor cells indirectly from the sequestered perfluorocarbon nanoparticles in the tumor periphery following systemic administration. In this study, we demonstrate the feasibility of measuring the direct intracellular pO2 of 9L gliosarcoma cells in the rat brain using 19F MRS. The 9L glioma cells were labeled with perfluoro-15-crown-5 ether (CE) prior to implantation and pO2 was measured using 19F T1 relaxation. The method will be used to study the real-time dynamics of tumor cell metabolism before and after the delivery of therapeutics.

17:00 801. MR-Visualization of Tumors in Mice by Dy-Loaded Liposomes as T2*-Susceptibility Agents. Evidence for a Macrophage Mediated Detection Silvio Aime1, Daniela Delli Castelli1, Enzo Terreno1, Claudia Cabella2, Massimo Visigalli, Linda Chabaane, Stefania Lanzardo, Carla Carrera 1University of Turin, Turin, Italy; 2CRM Cracco Imaging S.p.A., Italy

Dy(III) loaded liposomes are T2* susceptibility agents that provide an excellent visualization of tumors. The lack of specific tumor uptake in vivo has been associated to the efficient removal of liposomes operated by tumor associated macrophages.

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17:12 802. 19F MRS Allows Quantitative Evaluation of Anti-Angiogenic Therapy Delivered with Targeted Perfluorocarbon Nanoparticles Emily Alexandria Waters1, Ralph W. Fuhrhop1, John S. Allen1, Gregory M. Lanza1, Samuel A. Wickline1 1Washington University School of Medicine, Saint Louis, Missouri, USA

Once diagnosed, aortic valve disease can progress rapidly to critical stenosis requiring surgical valve replacement. We illustrate the use of molecularly targeted drug-bearing nanoparticles for both early diagnosis and therapy of experimental aortic stenosis (AS) by targeting the inflammatory angiogenic components of AS with the use of αv β 3-integrin binding perfluorocarbon nanoparticles. In this case MR spectroscopy of the unique 19F signal from the nanoparticles is used to quantify the extent of angiogenesis, which expresses the α;v β 3 integrin, and to measure the response to antiangiogenic drug therapy. We utilize a cholesterol-fed rabbit model of AS that exhibits gross thickening, macrophage infiltration, and angiogenesis with abundant α;v β 3 endothelial biomarkers that can be quantified with 19F MRS to report drug efficacy.

17:24 803. Correspondence of Magnetic Resonance Molecular Imaging to Quantitative Determination of E- And P-Selectin Expression in Acute Stroke Albert Yongwon Jin1, Ursula I. Tuor2, Jaspreet Kaur1, Dave Rushforth2, S Boutry3, Tadeusz Foniok2, Robert N. Muller3, Boguslaw Tomanek2, Philip A. Barber1 1University of Calgary, Calgary, Canada; 2National Research Council of Canada, Calgary, Canada; 3University of Mons-Hainaut, Mons-Hainaut, Belgium

Endothelial activation following cerebral ischemia and reperfusion involves the expression of the adhesion molecules P- and E-selectin. In a model of transient focal cerebral ischemia and reperfusion, magnetic resonance molecular imaging using the selectin-specific contrast agent Gd-DTPA-B(sLeX)A demonstrated differences in the accumulation of targeted and non-targeted contrast within the ischemic hemisphere in P-selectin knockout mice compared to the wild-type. These differences were correlated to the quantitative determination of P- and E-selectin expression in the brain, and led to the novel observation that E-selectin is upregulated in the ischemic hemisphere following acute stroke in P-selectin-deficient mice.

17:36 804. Manganese Guided Cellular MRI of Human Embryonic Stem Cell Viability Mayumi Yamada1, Paul T. Gurney1, Pratima Kundu1, Robert C. Robbins1, Phillip C. Yang1 1Stanford University, Stanford, California , USA

Human embryonic stem cells (hESC) have demonstrated the ability to restore the injured myocardium. MRI has emerged as one of the predominant imaging modalities using iron-oxide nanoparticles to localize the transplanted cells in the myocardium. However, fundamental biological information regarding the viability of the transplanted cells can not be monitored. In this study, we employed MnCl2 (manganese chloride) guided cellular MRI to determine viability of hESC.

17:48 805. Single Cell Level Detection of Gadolinium-Labeled Stem Cells Using a Clinical 3.0T MRI Scanner Monique Regine Bernsen1, Amber Davinia Moelker1, Sandra T. van Tiel1, Gavin C. Houston2, Gabriel P. Krestin1, Piotr A. Wielopolski1 1Erasmus MC, Rotterdam, Netherlands; 2GE Healthcare, Den Bosch, Netherlands

The ability to track transplanted cells in vivo is considered a crucial point in the development and validation of cell-based therapy. To overcome some limitations of the negative contrast provided by labeling of cells with iron-oxide particles, we have developed an efficient labeling method for incorporation of Gd into cells. Using cationic lipid-based nano-particles (Gd-lipo) efficient labeling of stem cells was achieved allowing visualization of cells by positive contrast at single cell level. Also in vivo imaging of approximately 10.000 labeled cells injected in the myocardium of living syngenic cells was achieved.

High Resolution Animal Imaging Room 715 A/B 16:00-18:00 Chairs: Alan P. Koretsky and Anne-Marie Van der Linden

16:00 806. In Vivo Tracking of Mesenchymal Stem Cells in the Injured Mouse Spinal Cord Laura Elizabeth Gonzalez-Lara1, Xiaoyun Xu1, Klara Hofstetrova1, Soha S. Ramadan1, Nicole Geremia1, Anna Pniak1, Yuhua Chen1, Lynne C. Weaver1, Brian K. Rutt1, Arthur Brown1, Paula J. Foster1 1Robarts Research Institute, London, Canada

To the best of our knowledge, this is the first report of in vivo stem cell tracking in a mouse model of spinal cord injury (SCI). Mesenchymal stem cells (MSCs) can be induced to differentiate into neural cells and MRI provides the opportunity to track the fate of MSCs transplanted into an injured spinal cord. Here we show, for the first time, the ability to monitor transplanted MSCs in mice with a clip compression spinal cord injury over 4 weeks using a fast 3D imaging sequence with a custom high-performance gradient coil insert at 3T.

16:12 807. Use of an OVS-FAIR Based ASL Technique for High Spatial Resolution Mouse Cervical Spinal Cord Blood Flow (SCBF) Mapping Guillaume Duhamel1, Virginie Callot1, Yann Le Fur1, Patrick J. Cozzone1, Frank Kober1 1CRMBM, CNRS 6612, Faculté de Médecine, Université de la Méditerranée, Marseille, France

A recent work has demonstrated the feasibility of mouse SC blood flow (SCBF) measurement with arterial spin labeling (ASL) using a flow-sensitive alternating inversion recovery (FAIR) technique at the cervical level. Although the achieved spatial resolution (130x130 μm2/pixel) permitted accurate measurements of SCBF within gray matter structures, higher spatial resolutions would be required for visualization and validation of longitudinal pathological changes in lesioned rodent SC. The combined use of a small volumic coil adapted to the SC imaging with an outer volume suppressed FAIR ASL technique was investigated for high spatial SCBF imaging (<100x100 μm2/pixel).

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16:24 808. The First in Vivo Mouse Proton and Sodium MR Imaging at 21 T Victor D. Schepkin1, William W. Brey1, Nathaniel D. Falconer1, Samuel C. Grant1, 2, Petr L. Gor'kov1, Kiran K. Shetty1, Timothy A. Cross1, 2 1National High Magnetic Field Laboratory/FSU, Tallahassee, Florida, USA; 2The Florida State University, Tallahassee, Florida, USA

High magnetic fields expand our ability to investigate biomedical processes. Yet, the highest magnetic fields bring challenges in probe design and animal adaptability. The first in vivo images of a mouse brain were acquired at the unique field of 21.1 T built at the NHMFL. These images were achieved by overcoming multiple obstacles in experimental in vivo design. Normal mice (C57BL/6J) images were acquired using proton (900 MHz) and sodium (237 MHz) MRI. The unique sodium MR images of mouse brain with resolution of 0.125 µL were obtained using a custom-designed 3D back-projection sequence.

16:36 809. Phase Imaging of the in Vivo Rat Brain at 14.1 Tesla José P. Marques1, 2, Cristina Cudalbu1, Carol Poitry-Yamate1, Vladimir Mlynarik1, Rolf Gruetter1, 3 1Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland; 2University of Lausanne, Lausanne, Switzerland; 3University of Lausanne and Geneva, Switzerland

Gradient-recalled echo (GRE) imaging at 14.1 Tesla (TE=15ms) was used to assess contrast in brain tissue both from the T2* weighted magnitude and from the phase image. In 4 min, a spatial resolution of 33µm was achieved. In addition to the excellent depiction of veins in the magnitude images, phase images suggest that susceptibility variations in rat brain are within ±0.01ppm of that of gray matter. The phase was inverted in structures ascribed to high myelination content (white matter-like) such as external capsules, anterior and posterior caudate, compared to that in vessels, hitherto not readily accessible using standard MRI techniques.

16:48 810. Virtual Mapping of Cyto-Architectonic Distinct Structures with MRI Daniel Barazany1, Ory Levy1, Tamar Blumenfeld-Katzir1, Yossi Yovel1, Yaniv Assaf1 1Tel Aviv University, Tel Aviv, Israel

Cytoarchitecture and myeloarchitecture are histological features that are used to segment the brain into neuroanatomical regions. In this work we used a multi-parametric MRI acquisition and analysis framework (virtual.com imaging) to compare the rat’s thalamus MRI segmentation with cyto-architecture mapping of the same sample. We found good correspondence between the MRI clusters and cyto-architectonic arrangement of the thalamus nuclei. In addition, the MRI contrast profile interpretation followed the cellular composition of the tissue. Cluster of multi-parametric MRI can evolve into an in-vivo cyto-architectonic mapping procedure that can be applied on the single subject level.

17:00 811. Magnetization-Prepared Segmented FLASH Sequences for High-Field Anatomical Brain Imaging in Animals Nicholas Adam Bock1, Frank Ye1, Afonso C. Silva1 1National Institutes of Health, Bethesda, USA

We compare three magnetization-prepared segmented FLASH sequences for high resolution 3D animal brain imaging at high field: MP-RAGE, MDEFT, and a segmented FLASH sequence with a delay between the segments. In simulations, the MP-RAGE sequence produces the best gray/white matter contrast, but little signal where the contrast is maximized. The segmented FLASH sequence produces the best signal, with proton density-weighted contrast that becomes good at longer delay times. We compare the MP-RAGE and segmented FLASH sequences in a marmoset at 7 Tesla. The segmented FLASH sequence proves advantageous because it produces a higher signal for SNR-limited high resolution 3D imaging.

17:12 812. In Vivo Visualization of Cerebro-Microvasculature Using 3D δR2-Based Microscopic MR Angiography (3D MMRA) Chien-Yuan Lin1, 2, Jyh-Hong Chen1, Ming-Huang Lin2, Wai-Mui Cheung2, Teng-Nan Lin2, Chen Chang2 1National Taiwan University, Taipei, Taiwan; 2Academia Sinica, Taipei, Taiwan

3D £GR2-Based Microscopic MR Angiography (3D mMRA) method is proposed and validated in order to evaluate the cerebro-microvasculature. The results demonstrate that 3D mMRA is a promising technique in monitoring and quantitatively evaluating microvascular remodeling in cerebro-microvascular disease.

17:24 813. Decreased Mean Diffusivity and Changes in Proton Spectra in the Brain of Aged Rats with Learning Deficits Ivan Vorisek1, Daniel Jirak2, Katerina Namestkova3, Milan Hajek2, Eva Sykova1 1Institute of Experimental Medicine ASCR, Prague, Czech Republic; 2Institute for Clinical and Experimental Medicine, Prague, Czech Republic; 3Charles University, 2nd Medical Faculty, Prague, Czech Republic

Cognitive decline in old age has been linked to changes in brain anatomy, morphology, volume, and functional deficits. Degenerative processes could also affect extrasynaptic transmission, mediated by the diffusion of transmitters through the extracellular space. Therefore, we studied diffusivity and changes in proton spectra in the brain tissue of aged rats with and without a learning deficit. Superior and inferior learners were selected according to their performance in a Morris water maze. Decreased mean diffusivity and changes in metabolite concentrations were found in aged inferior learners but not in aged superior learners.

17:36 814. MRI Can Detect Brain Shape Changes in Mice Caused by Five Days of Learning Jason P. Lerch1, Adelaide P. Yiu1, Veronique D. Bohbot2, R Mark Henkelman1, Sheena A. Josselyn1, John G. Sled1 1Hospital for Sick Children, Toronto, Canada; 2McGill University, Verdun, Canada

Mice were trained for five days on the Morris Water Maze, scanned at 32µm at 7T, and resulting MRIs analyzed for brain shape differences using deformation based morphometry. Significant results were found in multiple regions of the brain relating to the cogntive strategy used.

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17:48 815. Evidences of Learning and Memory Related Brain Plasticity from Diffusion Tensor Imaging in the Rat Tamar Blumenfeld-Katzir1, Ofer Pasternak2, Yaniv Assaf2 1Tel-Aviv University, Tel Aviv , Israel; 2Tel-Aviv University, Tel-Aviv, Israel

Brain Plasticity is defined as the ability of the brain region to re-organize following the demand for specific cognitive function. In this work we used DTI to follow morphological brain plasticity induced by learning and memory experience. Using a voxel-based analysis routine we compared the FA maps of rat brains before and after a learning and memory task. Following a 5-days learning and memory task, the FA in specific brain regions increased (hippocampus, septum and posterior part of the corpus callosum). This demonstrates that plasticity can be studied on morphological level and not only on the functional level.

Cardiac Cine & New Contrast Mechanisms Room 717 A/B 16:00-18:00 Chairs: Rohan Dharmakumar and Orlando P. Simonetti

16:00 816. Free Breathing and Breath-Held High Temporal Resolution (< 6 Ms) Cardiac Cine Steady State Free Precession (SSFP) Imaging for Estimation of Diastolic Function Ramkumar Krishnamurthy1, 2, Benjamin Y. Cheong2, 3, Raja Muthupillai2, 3 1Rice University, Houston, Texas, USA; 2St. Luke's Episcopal Hospital, Houston, Texas, USA; 3Baylor College of Medicine, Houston, Texas, USA

We describe a navigator-guided free breathing (Nav-SSFP), and a SENSE accelerated (Sen-SSFP) breath-held steady-state free precession (SSFP) cine imaging techniques that provide high temporal resolution (3-6 ms). We demonstrate that images acquired using these techniques can be used to measure various indices such as isovolumic relaxation time, time-to-peak filling rate, time-to-peak ejection rate, etc., for characterizing diastolic function as well as myocardial dyssynchrony. The results from our investigation in 10 normal subjects demonstrate that both techniques yield comparable metrics for quantifying diastolic function.

16:12 817. Real-Time Assessment of Right and Left Ventricular Volumes and Function in Patients with Congenital Heart Disease Using High Spatio-Temporal Resolution Radial K-T SENSE VIvek Muthurangu1, Andrew Taylor1, Philip Lurz1, Michael Hansen1 1UCL Institute of Child Health, London, UK

Study to assess the accuracy of ventricular volumes measured using high spatio-temporal resolution radial real-time imaging accelerated with kt-sense in patients with congenital heart disease. Compared to standard real-time imaging radial kt-SENSE images were of high quality. In addition, using cardiac gated imaging as a reference standard method, radial kt-SENSE was more accurate than standard real-time assessment of cardiac function. This technique offers the possibility of accurate real-time assessment of cardiac function. This may be particularly useful in patients who find breath holding difficult (i.e. children), and patients with irregular heart rhythms.

16:24 818. Real-Time M-Mode MRI Monitoring of Regional Wall Thickening Corinna S. Maier1, 2, Michael Bock2, Wolfhard Semmler2, Christine H. Lorenz3 1Siemens Corporate Research, Princeton, New Jersey, USA; 2German Cancer Research Center (dkfz), Heidelberg, Germany; 3Siemens Corporate Research, Baltimore, Maryland, USA

Monitoring the ECG for ischemic changes during dobutamine stress testing or MR-guided interventions is not possible in the MR environment due to the magnetohydrodynamic effect. A real time MR was converted to an m-mode (motion mode) representation analogous to echocardiography for simple continuous display of cardiac function. An active contours segmentation algorithm was developed to detecte the myocardial borders to enable the calculation of regional wall thickening. Preliminary results show that the method may allow semi-automated change detection as a monitoring method for CMR.

16:36 819. High Resolution Retrospective Reconstruction from Real-Time Acquired Cine MR Images Peter Kellman1, Christophe Chefd'hotel2, Christine H. Lorenz3, Christine Mancini1, Andrew E. Arai1, Elliot R. McVeigh4 1NIH, Bethesda, Maryland, USA; 2Siemens Corporate Research, Princeton, New Jersey, USA; 3Siemens Corporate Research, Baltimore, Maryland, USA; 4Johns Hopkins University, Baltimore, Maryland, USA

Real-time cardiac cine imaging typically has compromised image quality compared with gated, segmented breath-held studies. The proposed approach produces high quality cine images with high spatial and temporal resolution matching that of conventional segmented cine using fully automated retrospective reconstruction with real-time acquired image data.

16:48 820. Vector Map Visualisation of Phase Contrast Images Demonstrates Disruption of Intra-Atrial Vortices in Newborn Infants Alan M. Groves1, David J. Larkman1, Stephen T. Goldring1, Giuliana Durighel1, Julie A. Fitzpatrick1, Jo V. Hajnal1, A David Edwards1 1Hammersmith Hospital, Imperial College London, London, UK

Cardiac MR has demonstrated the presence of intra-atrial vortices in the adult heart which are thought to conserve the momentum of inflowing blood during atrial filling. Circulatory changes around the time of birth have potential to disrupt these vortices. In this work preliminary assessment of intracardiac flow in newborn preterm and term infants with phase contrast imaging is described, along with vector map visualisation of intra-atrial flow patterns. The potential mechanism and significance of this deviation from the adult pattern is discussed.

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17:00 821. Contrast-Agent Concentration Quantification During First-Pass MRA Using Susceptibility-Induced Magnetic Field Shifts Ludovic de Rochefort1, Thanh Nguyen1, Ryan Brown1, Martin R. Prince1, Yi Wang1 1Weill Medical College of Cornell University, New York, New York, USA

Paramagnetic contrast agents (CA) modify tissue susceptibility and distort magnetic fields in proportion to their concentration. The frequency shift is proportionnal to the contrast agent concentration and a shape factor which can be calculated provided that the shape is known. Here, using an inversion method, [CA] was measured continuously in the aortic arch during the first-pass MRA. Cardiac output was measured and compared to phase-contrast data evaluating the ability of the method to quantify susceptibility in vivo and derive physiological parameters.

17:12 822. Observing the Settling of Blood in the Supine Resting Condition in the Peripheral Vascular System Using SWI Ewart Mark Haacke1, 2, Jaladhar Neelavalli1, Samuel Barnes1, Zahid Latif1 1Wayne State University, Detroit, USA

The risk for deep vein thrombosis (DVT) increases with age and for travellers who are immobile for more than 4 hrs. In this abstract, using ssusceptibility weighted imaging, we show some evidence that points to the transient settling of blood as a possible cause of DVT.

17:24 823. Multi-Echo Dixon Fat and Water Separation Method for Detecting Fibro-Fatty Infiltration in the Myocardium Peter Kellman1, Diego Hernando2, Saurabh Shah3, Sven Zuehlsdorff3, Renate Jerecic3, Christine Mancini1, Zhi-Pei Liang2, Andrew E. Arai1 1NIH, Bethesda, Maryland, USA; 2University of Illinois, Urbana, Illinois, USA; 3Siemens Medical Solutions, Chicago, Illinois, USA

A Multi-echo Dixon fat and water separation method for detecting fibro-fatty infiltration in the myocardium can be used before or after contrast administration. The method is easy to use and provides improved contrast compared with conventional fat suppression.

17:36 824. Black-Blood Imaging of the Human Heart Using Rapid STEAM MRI Alexander Karaus1, Dietmar Merboldt1, Joachim Graessner2, Jens Frahm1 1Biomedizinische NMR Forschungs GmbH am MPI fuer biophysikalische Chemie, Goettingen, Germany; 2Siemens Medical Solutions, Hamburg, Germany

Because stimulated echoes dephase signals from moving spins, high-speed STEAM MRI sequences were developed for "black-blood" imaging of the heart that overcome limitations of double inversion-recovery techniques. Multislice images along anatomic orientations and triggered to end diastole were obtained from healthy subjects at 3 T. Optimum SNR and resolution of typically 2.0 × 2.0 mm2 (6 mm section thickness) were achieved by segmented multi-shot sequences with interleaved k-space acquisitions (160 ms each) from several heart beats during a single breathhold. Rapid STEAM MRI emerges as a simple technique for multislice imaging of the myocardial wall with efficient flow suppression.

17:48 825. Isotropic High-Resolution 3D MRI of Carotid Arterial Wall with Imporved Blood Suppression Using Motion-Sensitized Dephasing SPACE Zhaoyang Fan1, 2, Zhuoli Zhang1, Yiucho Chung3, Peter Weale3, John Sheehan1, Natasha Berg1, Ioannis Koktzoglou1, Mark Morasch1, Timothy Carroll1, 2, Renate Jerecic3, James Carr1, Debiao Li1, 2 1Northwestern University, Chicago, Illinois, USA; 2Evanston, Illinois, USA; 3Siemens Medical Solutions, Chicago, Illinois, USA

3D MRI offers advantages over 2D techniques for vessel wall visualization, but blood suppression and imaging time are more challenging. A motion-sensitized dephasing (MSD) preparation was combined with a fast 3D TSE sequence (SPACE), and residual intraluminal blood was suppressed dramatically at 3.0T. It was demonstrated on healthy volunteers and carotid atherosclearotic patients that MSD-SPACE is capable of achieving a superior spatial resolution (0.63 mm isotropic), shorter scan time, and significantly higher wall-lumen CNR efficiency as compared to multi-slice 2D TSE using inflow/outflow saturation band technique. MSD-SPACE is a promising technique for plaque screening in the carotid arteries at 3.0T.

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MORNING CATEGORICAL COURSE Safety Update Room 801 A/B 7:00 – 8:00 Chair: Penny A. Gowland

Educational Objectives: Upon completion of this course, participants should be able to:

• List the main interactions between the static field and the sensory organs in humans; • List the main interactions between the static field and cells; • Explain the origins of the inhomogeneous temperature rise in the body due to exposure to the RF field from an MRI RF coil, and predict

situations likely to lead to an increased risk of RF burns; • Decide how to recommend whether it is safe to scan someone with an implant; • Identify the hazards associated with MR contrast agents, and contrast different types of agents in terms of the risk profiles; and; • Compare the regulatory position for MRI across the world.

07:00 Regulatory Postiion: How ICNIRP Sets its Guidelines Paolo Vecchia 07:30 Regulatory Position: Regulatory Position Across the World Stephen F. Keevil

MORNING CATEGORICAL COURSE Ultra-High Field MR in Humans Room 718 A 7:00 – 8:00 Chairs: Klaas Pruessmann and Lawrence L. Wald

Educational Objectives: Upon completion of this course, participants should be able to:

• Explainn the importance of array technology for RF excitation and detection at ultra-high field, along with its basic modes of operation; • Distinguish different types of BOLD contrast in ultra-high-field fMRI and describe corresponding pulse sequences; • Name the key problems and their current solutions in ultra-high-field MRS; • List promising applications of ultra-high-field MR in and outside the brain and name their remaining limitations.

07:00 RF Pulse Strategies for Ultra-High-Field MRS James B. Murdoch 07:30 The Ingredients of a Successful MRS Study at Ultra-High Field Ivan Tkac

MORNING CATEGORICAL COURSE Absolute Beginners’ Guide to Anatomical and Functional MRI of the Human Brain Room 718 B 7:00 – 8:00 Chairs: Alan Connelly and Chloe Hutton

Educational Objectives: Upon completion of this course, participants should be able to:

• Identify the neuroanatomical and neurophysiological parameters which are accessible to MR measurement; • Describe the underlying physics of MR neuroimaging techniques; • Describe the data acquisition and analysis techniques most commonly used for anatomical and functional MRI of the brain; and • Recognize the potential value of advances such as parallel imaging, fast imaging techniques and high magnetic field strengths for imaging the

brain.. 07:00 Absolute Beginner’s Guide to Perfusion MRI Glyn Johnson

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MORNING CATEGORICAL COURSE Clinical Science for Physicists and Engineers Room 714 A/B 7:00 – 8:00 Chairs: Vivian S. Lee, Tim Leiner, and Bachir Taouli

Educational Objectives: Upon completion of this course, participants should be able to:

• Identify basic anatomy and physiology of the central nervous system, kidney, liver, cardiac, vascular and musculoskeletal systems; • Describe the process and diagnosis of stroke and white matter formation and damage; • Explain kidney and liver anatomy and function, and how MRI can be used to evaluate these organs; • Discuss basic cardiac physiology and the consequences of coronary artery disease and heart failure; • Describe the process of bone and cartilage formation and degeneration; and • Appraise unmet clinical needs that could potentially be solved by physicists and engineers.

MSK: Anatomy, Function, Pathology and Challenges 07:00 Bone: From Cortical Bone to Osteoporosis Thomas M. Link 07:30 Cartilage: From Form to Function Hollis Potter

MORNING CATEGORICAL COURSE Cardiovascular Molecular MR Contrast Agents: From Bench to Bedside Room 716 A/B 7:00 – 8:00 Chair: Peter Caravan

Educational Objectives: Upon completion of this course, participants should be able to:

• Define the specific challenges faced in molecular MRI and in particular explain the sensitivity limitations of MR contrast media; • List the different classes of contrast agents used and the strategies applied to enable molecular imaging with MR; • Identify molecular imaging agents being used in cardiovascular research; • Compare the different animal models used in cardiovascular molecular MRI and appraise the relative strengths of each; and • Describe two ways in which cardiovascular molecular MR imaging are being translated into clinical research.

07:00 Cardiovascular Molecular MRI in the Mouse David Sosnovik 07:30 Molecular MRI of Thrombosis: From Porcine Models to First Human Experiences Elmar Spuentrup

MORNING CATEGORICAL COURSE Mother and Fetus Room 701 A 7:00 – 8:00 Chairs: P. Ellen Grant and Nadine J. Girard

Educational Objectives: Upon completion of this course, participants should be able to:

• Describe what MR sequences are currently used in cutting edge fetal MRI: • Explain the potential clinical role of these sequences; and • Evaluate the limitations and challenges of fetal MRI.

07:00 MRI of the Fetal Nervous System: Technical Advances Nadine L. Girard 07:25 MRI of the Fetal Extra CNS Structures: Technical Advances Katia Chaumoitre

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MORNING CATEGORICAL COURSE Clinical Application of Cardiovascular Imaging Room 701 B 7:00 – 8:00 Chairs: Georg Bongartz and Stefan G. Ruehm

Educational Objectives: Upon completion of this course, participants should be able to:

• Describe state-of-the-art MR techniques for cardiac imaging; • List the various approaches to the assessment of cardiac function, perfusion, and viability; • Interpret cardiac MRI in various pathologies; • Explain recent approaches to vessel wall and luminal vascular imaging; and • Describe typical problems in cardiovascular imaging, including artifacts.

Practical Issues 07:00 Comprehensive Protocols for Imaging of Atherosclerosis Zahi A. Fayad 07:30 Comprehensive Protocols for Cardiac Imaging in Practice Jens Bremerich

MORNING CATEGORICAL COURSE Cell Tracking Room 713 A/B 7:00 – 8:00 Chair: Jeff W. M. Bulte

Educational Objectives: Upon completion of this course, participants should be able to:

• List at least four methods to label cells; • List disease models in which MRI cell tracking is an important tool; • Recognize which clinical trials have been performed and what is likely needed for future FDA approval; and • Identify what role interventional radiologists will play in the future.

Cell Tracking: Monitoring of MR-Guided Cell Injections 07:00 Principles of MR-Guided Injections Reed A. Omary

07:30 Real-Time Targeted Delivery and Imaging of Cells Aravind Arepally MORNING CATEGORICAL COURSE Hyperpolarization: How to Obtain and Use a 100,000-Fold Increase in Polarization Room 715 A/B 7:00 – 8:00 Chairs: John P. Mugler, III, and Brian K. Rutt

Educational Objectives: Upon completion of this course, participants should be able to:

• Describe “hyperpolarization,” that is, the physical process for generating nuclear polarization in certain gases or compounds that exceeds the thermal-equilibrium polarization achieved in typical MR scanners by several orders of magnitude;

• List the nuclei and compounds for which the hyperpolarized state has been achieved; • Identify the special requirements for MRI or MRS of hyperpolarized contrast media and describe pulse-sequence strategies that meet these

requirements; • List imaging and spectroscopy applications of hyperpolarized contrast media in animal models of disease; and • Implement hyperpolarized gas MRI in human pulmonary diseases for which it may improve detection and/or characterization compared to

current modalities.

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Hyperpolarized Gases: Animal & Human Applications 07:00 Applications of Hyperpolarized Gases in Animals Giles E. Santyr 07:30 Hyperpolarized Imaging in Humans: Overview, Rationale & Clinical Directions Talissa Altes

MORNING CATEGORICAL COURSE Tissue Contrast in MSK MRI: From Physics to Physiology Room 717 A/B 7:00 – 8:00 Chairs: Bernard Dardzinski and Timothy J. Mosher

Educational Objectives: Upon completion of this course, participants should be able to:

• Describe the physical and molecular basis for T1, T2, T1p and MT contrast as they relate to collagen-rich tissues; • Identify the effects of tissue anisotropy on relaxation properties; • Apply understanding of mechanism of image contrast in musculoskeletal MRI to clinical and translational research applications; and • Describe the ultra-short TE and T1p techniques and potential clinical applications.

07:00 T1rho Imaging: Techniques and Basis for Image Contrast Ravinder Reddy 07:30 MSK Clinical and Research Applications of T1rho Imaging Sharmila Majumdar

PLENARY LECTURES: Hyperpolarized 13C MRI: Development & Applications Hall F/G 08:15-09:30 Chairs: Martin O. Leach and Brian Rutt

8:15 826. PASADENA and the Hyperpolarization Renaissance Dan Weitekamp1 1California Institute of Technology, Pasadena, California , USA

The PASADENA (parahydrogen and synthesis allow dramatically enhanced nuclear alignment) method of hyperpolarization is complete in only several seconds and takes place in aqueous liquid. We review the physical principles and twenty-year history of the method, which has culminated in 13C polarizations of ~20% at sites with long T1, including the first such application to a metabolite, 1-13C succinate. Recent progress in pulse sequence design for the spin order transfer promises to extend this success to diverse small molecules of interest as MRI metabolic contrast agents. Developments relevant to other hyperpolarization methods are also included.

8:40 827. Metabolic Reactions Studied with 13C-DNP-MR in Vitro and in Vivo Rene in 't Zandt1 1Imagnia AB, Malmo, Sweden

The strong enhancement of the nuclear polarization by DNP-MR has profound impact on MR spectroscopy. Sensitivity improvement by many orders of magnitude widens the scope of MR to analytical areas not accessible by current state of the art MR techniques. By virtue of the method, MR analysis is completed in a time frame of the nuclear T1 (seconds for 13C). The method allows MR studies to be performed at physiological realistic concentrations in complex biological systems such as whole cells and living animals. Enzyme kinetics as well as metabolic profiles may be studied providing new insight to biochemical pathways.

9:05 828. Implementation and Applications of Hyperpolarized C-13 MRI in Medicine Sarah Nelson1 1UCSF, San Francisco, California , USA

Non-invasive biomarkers are valuable for characterizing pathology, tailoring treatment regimens to individual patients and evaluating response to therapy. The use of hyperpolarized 13C agents to obtain metabolic imaging data is of great interest for such applications. One of the first agents being considered for in vivo studies with dynamic nuclear polarization (DNP) is 13C1-labeled pyruvate, which is converted to lactate or alanine, dependent upon the needs of the tissue in question. Preliminary results obtained with this technology are extremely promising and provide strong motivation for considering cancer, diabetis and cardiac disease as targets for the application of this technology.

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Pulse Sequences: Better, Faster, Stronger Room 801 A/B 10:30-12:30 Chairs: Oliver Bieri and Jin Hyung Lee

10:30 829. High Resolution 2D Imaging Without Gradients with Accelerated TRASE Jonathan C. Sharp1, Scott B. King2, Donghui Yin2, Vyacheslav Volotovskyy2, Boguslaw Tomanek1 1National Research Council Institute for Biodiagnostics, Calgary, Canada; 2National Research Council Institute for Biodiagnostics, Winnipeg, Canada

We present the first experimental 2D imaging results of a new RF imaging method that does not use the frequency gradient hardware. The TRASE method employs a train of refocusing pulses applied to a sequentially-switched array of phase-gradient RF coils to encode k-space at high resolution. By rapid receive coil switching, during acquisition windows, k-space data acquisition can be significantly accelerated. This serial acceleration can be combined with generation of uncollected data points through k-space symmetries for acceleration factors exceeding the size of the coil array. Only a single transmitter and a single receiver channel are required.

10:42 830. Non-Fourier Imaging and Fast B0 Mapping with Linearly Ramped Gradients Laura Sacolick1, Douglas L. Rothman1, Robin A. de Graaf1 1Yale University, New Haven, Connecticut, USA

Most MRI applications use Fourier-based image reconstruction. Frequency offsets which are encoded along the time dimension are either indistinguishable from the constant, frequency-encoding gradient or are lost during the regridding of non-Cartesian data. By varying the gradients during acquisition, the additional time-dependence can be used to reconstruct both the spatial and spectral dimensions. Here a method is presented for reconstructing images acquired with arbitrary gradient functions by a vector-space projection similar to matched filtering. Here, applications of the technique to fast single-image B0 mapping and B0 insensitive spatial localization will be demonstrated.

10:54 831. High Speed MR Elastography Using SEA Imaging John Carl Bosshard1, Naresh Yallapragada1, Mary Preston McDougall1, Steven Michael Wright1 1Texas A&M University, College Station, Texas, USA

Magnetic resonance elastography (MRE) is of interest for assessing tissue stiffness non-invasively. While harmonic MRE requires only single frames to acquire stiffness information, transient MRE requires frames obtained at many temporal offsets to observe propagation of a mechanical transient. By eliminating phase encoding, single echo acquisition (SEA) MRI was used to obtain transient and harmonic elastography movies nearly 2 orders of magnitude faster than conventional MRI. Movies of transverse wave propagation in multiple region media were obtained and shear stiffness values were calculated from elastograms obtained from the velocity encoded data. The technique should be well-suited for transient MRE.

11:06 832. Multiple Repetition Time Balanced SSFP for Improved Spectral Response Tolga Çukur1, Dwight Georger Nishimura1 1Stanford University, Stanford, California , USA

Although balanced steady-state free precession (bSSFP) imaging yields high SNR efficiency, the bright lipid signal is often undesirable. FEMR and alternating repetition time SSFP have been proposed to create a stop-band around the fat-resonance and selectively image water. Nevertheless, the pass-band performance is sacrificed and the level of suppression is limited. A multiple repetition time SSFP scheme drastically improves the level of suppression without sacrificing the pass-band performance.

11:18 833. On the Use of Steady-State Equations to Estimate Signal Intensities in 2D TrueFISP Imaging Bram F. Coolen1, Edwin Heijman2, Klaas Nicolay1, Gustav J. Strijkers1 1Eindhoven University of Technology, Eindhoven, Netherlands; 2Philips Research Europe, Eindhoven, Netherlands

The signal intensity in 2D-TrueFISP images is often described by steady-state formulas. However, incorrect estimations may occur, because the slice selective excitation process can not be incorporated in these formulas. Therefore, the validity of using steady-state formulas for 2D-TrueFISP sequences was evaluated. To that end, measurements and Bloch-simulations were performed that give insight in the formation of steady-state slice profiles. These results were not always reproduced by methods using steady-state formulas. More importantly, this study showed under which circumstances the use of steady-state formulas resulted in correct estimations of the steady-state signal intensity.

11:30 834. Analysis of Eddy-Current Artifacts in Interleaved Balanced SSFP Jon-Fredrik Nielsen1, Krishna S. Nayak1 1University of Southern California, Los Angeles, California , USA

Many MRI applications, such as magnetization-prepared imaging with centric view-ordering, require large and frequent changes in the gradient waveforms from one TR to the next. In SSFP imaging, this is problematic, since residual eddy-current fields cause waveform-dependent changes in precession angle, causing signal distortions. Waveform “pairing” mitigates distortions for on-resonance spins, but its performance over the whole 1/TR SSFP bandwidth has not been validated experimentally. We investigate the effect of unequal precession angle on the steady-state magnetization in interleaved SSFP, and propose a strategy for mitigating signal distortions within the entire SSFP bandwidth.

11:42 835. Improved Shim Method for Balanced SSFP Jongho Lee1, 2, Michael Lustig2, Dong-Hyun Kim3, John M. Pauly2 1National Institute of Health, Bethesda, Maryland, USA; 2Stanford University, Stanford, California , USA; 3Yonsei University, Seoul, Republic of Korea

A new shim method that minimizes the maximum off-resonance frequency is proposed for bSSFP. The result shows an improved spatial coverage compared to the least square shim method.

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11:54 836. High Spatial Resolution, Volume Selective 3D FSE Imaging Manojkumar Saranathan1, Ken Hwang2, Reed Busse3, Paul Weishaar4, Akira Kawashima4, Christine Lee4 1Global Applied Science Lab, GE Healthcare, Rochester, Minnesota, USA; 2GE Healthcare, Houston, Texas, USA; 3GE Healthcare, Madison, Wisconsin, USA; 4Mayo Clinic, Rochester, Minnesota, USA

Although conventional multi slice 2D FSE is routinely used for tissue characterization of both malignant and benign processes, diagnostic limitations become apparent in small (e.g. prostate) and complex, tortuous (e.g. perianal fistulae) structures. It would be advantageous to use a high spatial resolution 3D acquisition scheme that would permit multiplanar reformatting. Near-isotropic 3D FSE acquisition has been beset by blurring caused by long echo-train lengths. Modulation of the refocusing flip angles in FSE to minimize signal modulation from T2 relaxation has enabled the use of long echo trains. In this study, we developed a novel technique that combines inner-volume (IV) selection and highly selective spatial saturation bands with an eXtended Echo Train Acquisition (XETA) 3D FSE-Cube sequence. This pulse sequence was evaluated for imaging of the prostate and perianal fistulae.

12:06 837. Flexible and Efficient View Ordering for 3D Sequences with Periodic Signal Modulation Reed F. Busse1, Anja C S Brau2, Philip J. Beatty2, Ersin Bayram3, Charles R. Michelich3, Anthony Vu3, Richard Kijowski4, Howard A. Rowley4 1GE Healthcare, Madison, Wisconsin, USA; 2GE Healthcare, Menlo Park, California , USA; 3GE Healthcare, Waukesha, Wisconsin, USA; 4University of Wisconsin, Madison, Wisconsin, USA

Many 3D sequences acquire multiple lines of k-space in a train while magnetization in a transient state, making view ordering an important factor in image quality. A new flexible view ordering method is presented that (a) increases sampling efficiency by using elliptical k-space coverage and non-separable 2D auto-calibration, (b) enables echo train lengths to be independent of matrix size, and (c) maps signal modulation into k-space smoothly to avoid artifacts. With 3DFSE applied to brain and knee imaging, the method is shown to reduce scan time or improve resolution by 1/3 while providing increased control of TE.

12:18 838. Towards Artifact-Free MRI Near Metallic Implants Wenmiao Lu1, Kim Butts Pauly1, Garry Evan Gold1, John Mark Pauly1, Brian Andrew Hargreaves1 1Stanford University, Stanford, California , USA

MRI near metallic implants remains an unmet need due to severe artifacts caused by huge metal-induced field inhomogeneity. In this work we present an imaging technique designed to achieve artifact-free MRI near metallic implants. The proposed technique combines slice excitation profile imaging (SEPI) and view angle tilting (VAT) technique. While the VAT completely eliminates in-plane distortion, the SEPI resolves the locations of excited spins with an additional phase encoding along the slice direction. When the spins subject to the metal-induced field inhomogeneity are resolved to their actual slice locations, summing the spins at the same location eliminates the through-slice distortion.

DTI of Neural Systems Room 718 A 10:30-12:30 Chairs: Seung-Koo Lee and Pratik Mukherjee

10:30 839. The Structural Core of Human Cerebral Cortex and Its Relation to the Brain’s Default Network Patric Hagmann1, Leila Cammoun2, Xavier Gigandet2, Reto Meuli1, Christopher J. Honey3, Olaf Sporns3 1University Hospital Center and University of Lausanne, Lausanne, Switzerland; 2Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; 3Indiana University, Bloomington, USA

Human cerebral cortex contains an uncertain number of structurally segregated regions interconnected by a dense network of axonal pathways. Using DSI, we map these pathways in individual human subjects. An analysis of the resulting large-scale structural brain networks reveals the existence of a core within the brain, as well as several distinct clusters. Regions within the structural core share high centrality and they form connector hubs that link all major modules of cortex. Most key regions of the human default network are also members of the structural core indicating an important role of the core in shaping functional integration.

10:42 840. Revealing the Topological Architecture of Human Cortical Anatomical Network by DTI Tractography Gaolang Gong1, Yong He2, Luis Concha1, Catherine Lebel1, Donald William Gross3, Alan Evans2, Christian Beaulieu1 1University of Alberta, Edmonton, Canada; 2McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University,, Montreal, Canada; 3Division of Neurology, Department of Medicine, University of Alberta,, Edmonton, Canada

An important issue in neuroscience is to reveal the architecture of complex brain network that might underlie fundamental structural and functional organization in the brain. This study employed DTI tractography to construct a macroscale anatomical network that captures the underlying common connectivity pattern of cerebral cortex across a population (N=80) of healthy young adults. This cortical network is found to exhibit small-world topology with the embedded pivotal nodes and connections mainly involving the association cortex regions and long-range white matter tracts, respectively. This finding might provide an insight into how anatomical connectivity of human brain underlies its functional states.

10:54 841. Rat Brain Connectivities After Stroke: Combined Application of Diffusion Tensor MRI (DTI), Manganese Enhanced MRI (MEMRI) and Functional MRI (FMRI) Aurore Camille Bogaert1, Guadalupe Soria1, Mathias Hoehn1 1Max Planck Institut for Neurological Research, Cologne, Germany

The aims of the present study were to establish and apply an optimized experimental protocol to investigate cortico-thalamic connectivity, in rat brain after stroke, longitudinally in individuals. The combination of high spatial and temporal resolution DTI, MEMRI and fMRI showed us dynamic structural and functional deficits following stroke during the observation period of 8 weeks. Thus we observed loss of BOLD signal on the S1 cortex while diffusion anisotropy was decreased across a large part of the ischemic territory, as seen on DTI and FA maps. In agreement, MEMRI showed no manganese transport when the cortico-thalamic connectivity was disrupted.

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11:06 842. Localization of Cognitive Function in Rats with Magnetic Resonance Imaging Tamar Blumenfeld-Katzir1, Ofer Pasternak1, Yaniv Assaf1 1Tel-Aviv University, Tel-Aviv, Israel

The brain localization of cognitive functions is limited to invasive lesion or electrophysiological studies. In this work we performed a diffusion tensor imaging study in rats. We correlated the FA and ADC indices with the rat's performance in a learning and memory task. We found that correlation between DTI indices and behavior performance is found in the limbic system: hippocampus, amygdale, olfactory complex and septum. These results imply that the cellular morphology of the limbic system correlates with learning and memory abilities of the rat.

11:18 843. Brain Localization of Cognitive Domains with Diffusion MRI Efrat Sasson1, Glen M. Doniger2, Ofer Pasternak1, Yaniv Assaf1 1Tel Aviv University, Tel Aviv, Israel; 2NeuroTrax Corporation, Newark, New Jersey, USA

In this study we investigated the relationship between changes in brain structures and cognitive performance in three cognitive domains – memory, verbal function, and information processing speed. Brains of 51 subjects age 25-82 were investigated using diffusion tensor imaging (DTI). Partial correlation was performed between ADC and the cognitive domains controlling for age, revealing a region-specific pattern of changes. The regions exhibiting substantial correlation in our study are known to play an important part in the corresponding functional domain. Thus, correlating cognitive performance and quantitative measures of brain morphology can be used for indirect functional localization of cognitive domain.

11:30 844. In Vivo Diffusion Spectrum Imaging Disentangles White and Gray Matter Connectivity in the Human Cerebellum Cristina Granziera1, Jeremy Dan Schmahmann2, Hubertus Fischer3, Thorsten Feiweier3, Karsten Jahns3, Heiko Meyer3, Reto Meuli1, Van J. Wedeen4, Gunnar Krueger5 1CHUV, Lausanne, Switzerland; 2MGH, Boston, Massachusetts, USA; 3Siemens Medical Solutions, Erlangen, Germany; 4Martinos' Center-MGH-Harvard medical school, Charlestown, Massachusetts, USA; 5Advanced Clinical Imaging Technology, Siemens Medical Solutions-CIBM, Lausanne, Switzerland

Numerous diseases such as ataxias, neoplasms, stroke and migraine affect the cerebellum, disrupting its highly complex brain structure. So far, most of the knowledge of cerebellar anatomy has been obtained through ex vivo approaches, structural MRI and Diffusion tensor imaging. These approaches, however, fail to accurately render cerebellar white and grey matter connectivity. In this study, we were able to disentangle for the first time in vivo cerebellar white and grey matter connectivity using diffusion spectrum imaging (DSI) at 3T. DSI clearly proofs to be a very promising technique to identify prognostic and monitoring markers of diseases affecting the cerebellum.

11:42 845. Segmentation of Sensory Pathways in Human Trigeminal Ganglion and Brain Stem Jaymin Upadhyay1, Jamie Knudsen1, Julie Anderson1, Lino Becerra1, David Borsook1, 2 1P.A.I.N. Group, Brain Imaging Center, McLean Hospital, Belmont, Massachusetts, USA; 2Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, USA

Diffusion tensor probabilistic tractography was implemented to map sensory and pain pathways in human trigeminal ganglion and brain stem. Peripheral trigeminal nerve branches (V1, V2 and V3) were segmented at the level of the trigeminal ganglion. V1, V2 and V3 were found to converge to form the trigeminal nerve root, which enters the brain stem at the mid-pontine level and projects towards caudal pontine regions. Lastly, the spinal thalamic and trigeminal thalamic pathways within the brain stem were segmented. DTI-based segmentation of sensory and pain pathways was comparable to conventional histological findings in human trigeminal ganglion and brain stem.

11:54 846. Fiber Tracking of Cervical Spinal Cord and Nerves Thomas Benner1, André J. W. van der Kouwe1, Denise P. Yates1, Graham C. Wiggins1, Ruopeng Wang1, Van J. Wedeen1, A. Gregory Sorensen1 1Athinoula A. Martinos Center, Charlestown, Massachusetts, USA

Feasibility of fiber tracking of human cervical spinal cord and nerves based on DTI was examined. DTI was performed at 3 T using a custom 8-channel coil placed in close proximity to the neck. A spatial resolution of 1.5x1.5x1.85 mm3 was achieved in 13 min. Fiber tracking and visualization were performed using custom-made programs. Spinal cord as well as nerves could be visualized well. This study shows that diffusion tractography has unique potential for imaging spinal cord and roots, and that the basic technical barriers to tractography in the peripheral nervous system can be overcome by using existing technologies.

12:06 847. Building an Atlas of the Subcortical White Matter: Identification and Assignment of Common Anatomical Structures Kenichi Oishi1, Karl Zilles, Katrin Amunts, Hangyi Jiang1, Xin Li, Kazi Akhter1, Kegang Hua1, Roger Woods, Arthur Toga, Gilbert Bruce Pike, Pedro Rosa-Neto, Alan Evans, Jiangyang Zhang1, Hao Huang1, Michael I. Miller, Peter C. van Zijl1, John Mazziotta, Susumu Mori1 1Johns Hopkins University, Baltimore, Maryland, USA

Anatomy of subcortical white matter (SWM), which bridges the deep white matter and the cortex, has not been comprehensively characterized in the past. In this study, we linearly normalized DTI data from 81 healthy subjects to the ICBM-152 coordinate space and identified common anatomical features in this region. We found that the SWM consisted of nine blade-like structures. These structures were parcellated and annotated in ICBM and Talairach spaces. Four U-fibers were also identified inter-connecting these 9 structures. This atlas is now available and is expected to enhance our understanding of involvement of the SWM in various brain diseases.

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12:18 848. Implicit Reference-Based Group Registration of Diffusion Tensor Imaging Xiujuan Geng1, Hong Gu1, Thomas J. Ross1, Gary E. Christensen2, Yihong Yang1 1National Institute on Drug Abuse, NIH, Baltimore, Maryland, USA; 2The University of Iowa, Iowa City, Iowa, USA

An implicit reference-based group-wise (IRG) registration method was proposed and applied on population study of the fractional anisotropy (FA) derived from diffusion tensor imaging (DTI). This method does not require a template, and registers all images simultaneously to an implicit reference, which is the population mean in a general metric space. The results demonstrate that the IRG method has better performance in terms of smaller cross subject variance after registration compared to reference-based techniques. This may improve the sensitivity to detect subtle changes in white matter integrity between populations.

Hemodynamic Stress & Metabolic Measure Room 718 B 10:30-12:30 Chairs: Karla L. Miller and Bruce Pike

10:30 849. Caffeine Does Not Affect Regional Vascular Reactivity to CO2 Yufen Chen1, 2, Todd B. Parrish1 1Northwestern University, Chicago, Illinois, USA

Caffeine is a widely consumed methylxanthine that acts as an antagonist to adenosine and decreases cerebral blood flow through vasoconstriction. Previous work using ultrasound has shown that there are no differences in vasoreactivity in the middle cerebral arteries; however, detailed regional analysis has not been done to date. In this study, we use a combination of arterial spin labeling and BOLD to demonstrate that caffeine does not alter vascular reactivity to CO2 in motor and visual cortices.

10:42 850. Negative BOLD Signal Under 6% Hypercapnia Reflects Solely Oxygen Extraction from the Blood Anne-Catherin Zappe1, Kamil Uludag1, Nikos K. Logothetis1, 2 1Max-Planck-Institute for biological Cybernetics, Tuebingen, Germany; 2University of Manchester, Manchester, UK

The BOLD signal is sensitive to cerebral blood flow (CBF), blood volume (CBV) and oxygen extraction. In the anesthetized monkey, we observe a vasodilatory ceiling effect during inhalation of 6% CO2 where CBF or CBV are not further increased by visual stimulation. In contrast, simultaneously measured local field potential responds to the stimulation as strong as during normocapnia. As a consequence, the stimulus-induced fMRI response during 6% hypercapnia has been found to be negative reflecting only the oxygen extraction from the blood. With this method, oxygen extraction can be imaged by means of fMRI without injection of an exogenous drug.

10:54 851. Validation of Oxygen Extraction Fraction Measurement by QBOLD Technique Xiang He1, Mingming Zhu1, Dmitriy A. Yablonskiy1 1Washington University in St Louis, School of Medicine, St. Louis, USA

Measurement of brain tissue oxygen extraction fraction (OEF) can provide important information on brain functioning in health and disease. The recently proposed quantitative BOLD (qBOLD) model allows for separation of contributions to the BOLD signal from OEF and deoxygenated blood volume (DBV). The objective of this study is to validate qBOLD OEF measurements in a rat model. The qBOLD OEF results averaged across entire brain were compared with the oxygenation of venous blood samples drawn directly from the superior sagittal sinus and measured with a blood gas analyzer. The results demonstrate a very good agreement between qBOLD and direct measurements.

11:06 852. Non-Invasive Quantification of Venous Oxygenation and Cerebral Metabolic Rate of Oxygen in Humans Feng Xu1, Hanzhang Lu1 1University of Texas Southwestern Medical Center, Dallas, USA

T2-Relaxation-Under-Spin-Tagging (TRUST) MRI, a recently developed technique to quantify cerebral venous oxygenation (Yv) non-invasively, is applied to measure internal jugular veins (IJV) Yv. The blood T2 values in the IJVs were 62.8±10.6ms, corresponding to a Yv of 64.3±7.2%. Compared with sagittal sinus (SS), whose T2 is 57.9±9.1ms and Yv was 62.2±6.1%, no significant difference is found by pair t-test (p=0.13, n=12). The IJV Yv is further combined with venous flux (52.7±11.1ml/100g brain/min) acquired by phase contrast (PC) scan for eight subjects, giving whole-brain cerebral metabolic rate of oxygen (CMRO2) of 1.46± 0.20 µmol/g/min.

11:18 853. Estimation of the Regional Cerebral Metabolic Rate of Oxygen Consumption with MRI During the First 60 Seconds of 17O2 Inhalation in Swine Eric Albert Mellon1, Reddy Shashank Beesam1, James E. Baumgardner1, Arijitt Borthakur1, Walter R. Witschey1, Ravinder Reddy1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA

The non-radioactive, naturally-occurring, NMR active isotope 17O can be used for the non-invasive, non-toxic, and widely-employable quantification of tissue metabolism. We demonstrate measurement of CMRO2 in pigs before recirculation. A custom circuit for precise 17O2 delivery provides a step change of mouth gas concentration. A simple model of lung mixing is presented. Analysis of arterial H217O shows the time until recirculated H217O starts to be 60-80 seconds. Indirect and direct imaging is correlated to estimate CMRO2 non-invasively during that time. Only one breath of 17O2 is used, reducing cost significantly. For indirect imaging, only a clinical 1.5T scanner is required.

11:30 854. The Relation Between BOLD Amplitude and Baseline Cerebral Blood Flow Depends on the Analysis Scale Joy Liau1, Joanna Perthen1, Thomas T. Liu1 1University of California at San Diego, La Jolla, California , USA

The baseline cerebral blood flow (CBF) may influence the BOLD response amplitude through: 1) changes in the maximum BOLD response and 2) changes in the functional CBF response. In this study, we show that changes in the functional CBF response dominate BOLD variability in subject-wise measurements while changes in the maximum BOLD response dominate in voxel-wise measurements. These results are consistent with the theory that the oxygen extraction fraction is inversely related to resting blood flow across subjects but is relatively independent of baseline blood flow across voxels.

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11:42 855. Normalization of FMRI Signal with Basal Physiologic State Improves Sensitivity in Differentiating Subject Groups Hanzhang Lu1, Uma Yezhuvath1, Kelly Lewis-Amezcua1 1University of Texas Southwestern Medical Center, Dallas, USA

We have previously shown that cerebral venous oxygenation can be quantified with TRUST MRI and that stimulation-evoked fMRI signal is inversely correlated with baseline oxygenation across subjects. Here we aim to test the utility of TRUST MRI in distinguishing subject groups. Checkerboards flashing at 8Hz and 4Hz were presented to two healthy control groups, respectively. Comparison between the groups with and without using TRUST MRI showed that the inter-subject variation was substantially reduced and group separation was more significant after the normalization. These results suggest that TRUST MRI may be beneficial for fMRI studies of psychiatric and neurological disorders.

11:54 856. Reproducibility of BOLD Signal Change Induced by Breath Holding Stefano Magon1, Gianpaolo Basso2, Paolo Farace1, Giuseppe K. Ricciardi3, Andrea Sbarbati1, Alberto Beltramello3 1University of Verona, Verona, Italy; 2University of Trento, Mattarello, Italy; 3Borgo Trento Hospital, University of Verona, Italy

The aim of the present study was to investigate the changes and reproducibility of BOLD signal, within and across subjects, in response to different Breath Holding (BH) durations (9, 15 or 21 seconds). The parameters of the BOLD BH-induced response (Percent Signal Change, Time To Peak, Integral of Subtended Area and the number of activated voxels) were significantly different among the three BH durations. The reproducibility of the signal is directly dependent on the duration of the BH, being better for longer BH, possibly because subject’s brain vascular reactivity is pushed toward its maximum

12:06 857. Hypercapnia-Based Calibration Techniques for Measurement of Cerebral Oxygen Metabolism with MRI Knut Drescher1, Peter Jezzard2, Daniel Bulte2 1University of Cambridge, Cambridge, UK; 2University of Oxford, Oxford, UK

Three different methods of obtaining a hypercapnic state were compared for their applicability as calibration steps for functional MRI. Breathing carbon dioxide in air, carbon dioxide in oxygen and breath holding were investigated in healthy volunteer subjects to determine the effects that each technique had on physiology, flow, BOLD signal and relaxation times. Of the three methods, breathing an increased fraction of CO2 in air proved to be the preferred option, having the fewest complications which limit the effectiveness of the models in regards to changes in arterial oxygen saturation and apparent changes in metabolism.

12:18 858. Measuring the Effect of Hyperoxia and Hypercapnia on R2* and the Balanced SSFP Signal at 3T Stefanie Winkelmann1, Hannes Dahnke1, Sebastian Flacke2, Martin Söhle2, Ingobert Wenningmann2, Attila Kovacs2, Frank Träber2, Juergen Gieseke3, Hans Heinz Schild2, Petra Mürtz2 1Philips Research Europe, Hamburg, Germany; 2University Hospital Bonn, Bonn, Germany; 3Philips Medical Systems, Hamburg, Germany

The effect of hypercapnia (elevated level of CO2) and hyperoxia (elevated level of O2) on the MRI signal is of major diagnostic value in the field of oncology as it gives insight into a wide range of tumor parameters, e.g. the vascular growth, hemodynamic changes in the response to treatments, vasoreactivity, vascular function and vessel maturation. This work compares the MR response of R2* and the balanced SSFP signal to hyperoxia and hypercapnia in terms of time course and sensitivity, using respiratory challenges in 5 healthy volunteers during MR imaging.

MR Biomarkers: Ex Vivo Characterization of Human Tissue Samples Room 714 A/B 10:30-12:30 Chairs: John R. Griffiths and Sabrina M. Ronen

10:30 Invited Speaker: Characterization of Human Tissue Samples by Ex Vivo MR, When, Why, and How Edward J. Delikatny, Ph.D. University of Pennsylvania, Department of Radiology, Philadelpha, PA, USA

11:06 859. Metabolic Profiling of Changes in the Transition from Pre-Invasive to Invasive Cervical Cancer Using Magic Angle Spinning Magnetic Resonance Spectroscopy of Intact Tissues Sonali S. De Silva1, Geoffery S. Payne1, Valerie A. Thomas2, Thomas E. Ind2, Nandita M. deSouza1 1Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Sutton, UK; 2St Georges Hospital NHS Trust, Tooting Broadway, UK

The development of invasive cervical cancer is preceded by a well-defined pre-invasive stage, cervical intraepithelial neoplasia (CIN). Elevated levels of choline have previously been identified in a number of tumours including cervical cancer [1] but whether these metabolites are elevated in CIN tissue is still unclear. The study investigates the metabolic changes in the transition from normal-to-pre-invasive, and from pre-invasive to invasive cervical cancer using 1H and 31P HR-MAS MRS of intact tissues in which the tissue content was subsequently confirmed with histology. Targeted biopsies were obtained on colposcopy in cervical intraepithelial neoplasia, CIN, (low-grade n=5, high-grade n=40) and on visual inspection when invasive disease was clinically obvious (n=23). Cervical tissues were also obtained from women with normal smears undergoing hysterectomy for benign uterine disease (n=5). Mean concentrations of Aln, Cr, Cho, PC, Tau in 1H HR-MAS and PC, PE and Pi in 31P HR-MAS were calculated. HR-MAS spectral analysis shows significant differences between invasive cervical cancer and high-grade CIN. Increased levels of choline-containing compounds are observed in cancer tissue. Our findings also suggest that normal tissue adjacent to tumour shows some metabolite depletion, while concentration of choline-containing metabolites is increased in CIN tissue adjacent to a malignancy. Changes in choline metabolism may be a useful biomarker in identifying the transition of pre-invasive to invasive disease.

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11:18 860. Quantitative Metabolic Profiling of Second and Third Trimester Human Amniotic Fluid Via High-Resolution MR Spectroscopy: Analysis for Biomarkers of Fetal Maturation Brad R. Cohn1, Bonnie N. Joe1, Shoujun Zhao1, John Kornak1, Vickie Yi Zhang1, Rahwa Iman1, John Kurhanewicz1, Jingwei Yu1, Aaron B. Caughey1, Mark G. Swanson1 1UCSF, San Francisco, California , USA

High-resolution MR spectroscopy was used to quantify 21 metabolites in second and third trimester human amniotic fluid samples (N=50). Significant differences were found for 15 of 21 metabolites. Glucose and several amino acid concentrations decreased, while creatinine and betaine increased with gestational age. Stepwise linear regression models suggested that gestational age could be accurately predicted using combinations of alanine, glucose, and creatinine concentrations. This study provides normative data for assessing fetal development, evidence of pulmonary and renal maturation, and may aid in the application of in vivo MRS as a future non-invasive test for evaluating fetal development.

11:30 861. HR-MAS Spectroscopy of Human Testicular Biopsy Tissue Demonstrates Phosphocholine as a Biomarker of Male Fertility Rahwa Iman1, Mark Swanson1, Paul J. Turek1, David Aaronson1, Helena Gurascier1, Dan Vigneron1, Sarah Nelson1, John Kurhanewicz1 1University of California San Francisco, San Francisco, California , USA

1H high resolution magic angle spinning (HR-MAS) spectroscopy was used to determine the metabolic profiles of normal, maturation arrested, and azoospermatic human testicular biopsy tissues. Fourteen 1H HR-MAS spectra were acquired and quantified using the electronic standard ERETIC and the algorithm QUEST. Phosphocholine (PC) concentrations were significantly higher in normal versus azoospermatic testes and there was no overlap between the two groups. However, PC concentrations in maturation arrested testes overlapped both normal and azoospermatic testes. This study suggests that PC could serve as a specific in vivo marker for fertility in 1H MRSI studies of human testes.

11:42 862. Metabolomics-Based Viability Assessment of Cystic Echinococcosis Using High-Field 1H-MRS of Biopsies William E. Hull1, Waldemar Hosch2, Günter W. Kauffmann2, Thomas Junghanss2 1German Cancer Research Center (DKFZ), Heidelberg, Germany; 2University Clinic Heidelberg, Heidelberg, Germany

Cystic echinococcosis (CE) or hydatid disease is caused by larval stages of the cestode parasite Echinococcus granulosus (canine tapeworm) and is a zoonosis of worldwide distribution. Clinical staging of cyst development by ultrasonography (US) requires accurate assessment of cyst viability, assuming a correlation between cyst morphology and parasite viability (light microscopy). Using high-field 1H-MRS of 50 cyst biopsies, 48 metabolite parameters were determined, and multivariate analysis provided excellent discrimination between viable and nonviable cysts, regardless of US class, as well as a rationale for discriminating between individual US classes.

11:54 863. Identification of Amide Protons of GSH in MR Spectra of Tumor Cells Sveva Grande1, Anna Maria Luciani1, Antonella Rosi1, Laura Guidoni1, Vincenza Viti1 1Istituto Superiore di Sanita', Roma, Italy

MRS can be used to monitor intracellular pH in in vitro and in vivo samples. Amide signals were chosen to this purpose, because their intensity is related to pH value. The origin of these signals is not yet clear. In the present work, through the comparison of spectra from tumor cells and from GSH solution, we assign two main peaks of the 1H MR cell spectra to NH protons of gly and cys of GSH. Assignment is confirmed by treatment of cells with buthionine sulfoximine (BSO), that inhibits the activity of the enzymeï€ Î³-glutamyl cysteine synthetase.

12:06 864. 1H MRS of Sputum for the Non-Invasive Diagnosis of Lung Cancer Tedros Bezabeh1, Celia Marginean2, Garth Nicholas2, Omkar B. Ijare1 1National Research Council Institute for Biodiagnostics, Winnipeg, Canada; 2The Ottawa Hospital, Ottawa, Canada

Application of 1H MR spectroscopy for the detection of lung cancer has been investigated. Sputum samples from lung cancer patients and normal controls were analyzed by 1H MRS. Glucose was found to be absent in sputum samples obtained from lung cancer patients. The absence of glucose could be due to an increased rate of glycolysis in the lung cancer cells in these patients. Cancer cells rely heavily on glycolysis for their metabolic demands since they cannot produce energy from pyruvate, due to a defective Krebs cycle. This observation may have a diagnostic potential for the rapid and non-invasive diagnosis of lung cancer.

12:18 865. Temperature Effect on the HRMAS Spectra of Human Brain Tumour Biopsies, Their Pattern Recognition Analysis and Their Post-HRMAS Histopathology Daniel Valverde-Saubí1, 2, Ana Paula Candiota, 12, Maria Antonia Molins3, Miguel Feliz3, Oscar Godino4, Juan Martino4, Juan José Acebes4, Carles Arús1, 2 1Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain; 2Centro de Investigación Biomédica en Red de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Cerdanyola del Vallès, Spain; 3Universitat de Barcelona, Barcelona, Spain; 4Hospital Universitari de Bellvitge, L'Hospitalet del Llobregat, Spain

We investigated the recording temperature effects on the HRMAS spectral pattern and on supervised classifier development. HRMAS spectra were acquired at 0ºC and 37ºC and analysed using pattern recognition techniques. Post-HRMAS histopathology was carried out. Major reversible temperature dependent changes were detected on the spectral pattern of the samples analysed. A better classification was achieved using the spectra acquired at 0ºC. Sample morphology was essentially not affected by 37ºC HRMAS analysis. The temperature dependent changes explain the better classification at 0ºC. Higher dispersion of data at 37ºC could be due to the existence of molecular subtypes of glioblastoma.

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Obesity & Diabetes Room 716 A/B 10:30-12:30 Chairs: Fritz Schick and Dikoma C. Shungu

10:30 866. Abdominal Fat Measurement: MRS vs. MRI Min-Hui Cui1, 2, Vlad Tomuta1, CJ Segal-Isaacson1, Daniel T. Stein1, Jong-Hee Hwang1 1Albert Einstein College of Medicine, Bronx, New York, USA

The assessment of abdominal fat by MRS vs. MRI on a cohort of subjects is reported. Both methods provide comparable quantitative measurements of abdominal fat depots. However, MRI is a better choice to measure abdominal fat as well as subcutaneous and intra-abdominal fat. Nevertheless, MRS on small voxel in subcutaneous fat detected fatty acid composition changes with diet in that a higher intake of fat caused increased proportional content of saturated fatty acid in adipose tissue triglycerides.

10:42 867. What Happens After Two Years of Lifestyle Intervention? Changes in Different Adipose Tissue Compartments Assessed by MRI and MRS Jürgen Machann1, Claus Thamer2, Fabian Springer1, Norbert Stefan2, Hans-Ulrich Haring2, Claus D. Claussen3, Andreas Fritsche2, Fritz Schick1 1Section on Experimental Radiology, Tübingen, Germany; 2Department of Endocrinology, Metabolism, Clinical Chemistry, Nephrology and Angiology, Tübingen, Germany; 3Department of Diagnostic Radiology, Tübingen, Germany

Due to its increasing prevalence, overweight and obesity as well as the concomitant diseases as type 2 diabetes (T2DM) are a hot topic in our modern society. MR examinations were performed in a cohort of 130 subjects (3 examinations each) at increased risk for T2DM during a lifestyle intervention (LI) program of 2 years for quantification of different adipose tissue (AT) compartments and their changes after LI. Visceral AT and hepatic lipids showed the most prominent changes whereas subcutaneous AT was almost unchanged. Further factors influencing the success of LI – as genetic predispositions – are discussed.

10:54 868. Understanding Ethnic Differences in Body Adiposity in the Newborn Vimal Vasu1, Louise Thomas2, Chitranjan Yajnik3, Shalini Umranikar3, Peter McEwan1, Sabita Uthaya1, Jimmy Bell2, Neena Modi1 1Imperial College London, London, UK; 2Hammersmith Hospital, Imperial College London, London, UK; 3King Edward Memorial Hospital and Research Center, Pune, India

South Asians (SA), have higher prevalence of diabetes and insulin resistance and show ethnic differences in body composition. Here we investigate, using whole-body magnetic resonance imaging (MRI), whether such differences are apparent at birth. We compared body adiposity in 53 Caucasian and SA neonates and show that the latter have altered body fat distribution, although the overall content is the same.

11:06 869. Liver and Muscle Lipid Stores and Their Association with Abdominal Fat Distribution in Healthy Elderly Individuals Alison Sleigh1, Francis Finucane2, David Savage1, Jessica Horton2, Lisa Purslow2, Sally Harding1, T A. Carpenter1, Nick Wareham2 1University of Cambridge, Cambridge, UK; 2Institute of Metabolic Science, Cambridge, UK

70 healthy elderly volunteers (aged 67-76 years) were recruited for measurements of abdominal fat distribution using MR imaging and IHL and IMCL using single voxel 1H-MR spectroscopy. Results suggest that IHL is closely related to measures of abdominal fat distribution and compartmentalisation. After adjusting for age and BMI, IHL was found to be more strongly associated with visceral and visceral/subcutaneous ratio, rather than subcutaneous fat. Our findings are consistent with studies in younger individuals, but have not been reported in an older cohort such as ours until now.

11:18 870. A Comparison of Hepatic Lipid and Glycogen Levels in Type II Diabetics Using 1H and 13C MRS Mary C. Stephenson1, Emily Leverton1, Eric Y. H. Khoo1, Simon M. Poucher2, Carsten Liess3, Andrew J. Lockton3, Lars Johansson4, 5, Jan W. Eriksson, 46, Peter Mansell1, Ian A. MacDonald1, Peter G. Morris1 1University of Nottingham, Nottingham, UK; 2AstraZeneca , Macclesfield, UK; 3AstraZeneca, Macclesfield, UK; 4AstraZeneca, Mölndal, Sweden; 5Uppsala University Hospital, Uppsala, Sweden; 6Sahlgrenska University Hospital, Gothenburg , Sweden

Metabolic disturbances in diabetes may include an increase in hepatic lipid concentration which has been suggested to contribute to the level of insulin resistance. The purpose of this study was to compare basal lipid and glycogen levels using 1H and 13C MRS both in type II diabetic and in healthy age and BMI matched subjects. Liver lipid levels were approximately 3-fold higher in the diabetic group, when compared with the healthy subjects which was not reflected in hepatic glycogen levels. Our results also suggest that the degree of diabetic control and level of obesity may affect liver lipid concentration

11:30 871. Abnormal Exercise Function in Adolescents with Type 2 Diabetes Correlates Negatively with Soleus Muscle IMCL as Measured by 1H MRS Mark Steven Brown1, Deb Singel1, Judith Regensteiner1, Jane Reusch1, Kristen Nadeau1 1University of Colorado Health Sciences Center, Aurora, Colorado , USA

Adults with type 2 diabetes (T2D) exhibit impaired maximal exercise capacity (VO2max). We explored whether VO2max is also reduced in adolescents with T2D, by performing measurements of muscle extramyocellular lipids (EMCL) and intracellular lipids (IMCL) using 1H MRS in the soleus and tibialis anterior muscles, as well as VO2max, blood flow, autonomic function, body composition, inflammatory markers, and insulin sensitivity, in lean, obese, and T2D adolescents. The results show VO2max/kg was significantly lower in T2D vs. obese vs. lean subjects, and that VO2max inversely correlates with IMCL, as well as with markers of insulin sensitivity, endothelial function, and inflammation.

11:42 872. Insulin-Stimulated Mitochondrial ATP Synthesis is Impaired in Rat Muscle by Fat-Enriched Diet Brittany Yerby1, Valerie Beaulieu, Richard Deacon, Jinsheng Liang, Jiaping Gao, Didier Laurent1 1Novartis Institutes for Biomedical Research, Inc, Cambridge, Massachusetts, USA

This study describes the inhibitory effects of increased lipid availability on insulin-stimulated ATP synthesis rates as measured in rat muscle by 31P saturation transfer. The euglycemic-hyperinsulinemic clamp approach used here not only improves sensitivity, but also mimics a physiological challenge that is relevant for pharmacological studies on anti-diabetic drugs aimed at improving mitochondrial function.

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11:54 873. Impact on Basal and Maximal ATP Turnover of Structured Physical Activity Counselling in Type 2 Diabetes: A 31P MRS Study Kieren Grant Hollingsworth1, Michael I. Trenell1, Ee Lin Lim1, Jean Gerrard1, Roy Taylor1 1Newcastle University, Newcastle Upon Tyne, UK

In type 2 diabetes (T2D), it is hypothesised that impaired mitochondrial function reduces the ability of muscle to metabolise fatty acids. Previous studies show that glucose control is improved by structured exercise counselling, but the mechanism of this improvement is unclear. We have measured both basal and maximal ATP turnover by 31P MRS before and after an eight-week physical activity intervention on 10 sedentary T2D patients and 10 controls matched for age, sex and physical activity. The counselling successfully achieved increased activity, weight loss and improvement in lipid oxidation, but neither measure of ATP demand changed due to the intervention.

12:06 874. Manganese Enhanced MRI Detects Pancreatic Beta Cell Function in Vivo Patrick Francis Antkowiak1, Sarah Ann Tersey, Raghavendra G. Mirmira, Frederick H. Epstein 1University of Virginia, Charlottesville, USA

In normal individuals, pancreatic beta cells release insulin into the bloodstream after an increase in blood glucose level. In Type 1 diabetes, beta cell mass and function are impaired. Manganese-enhanced MRI has been used previously to probe beta cell function in vitro; we aimed to evaluate its effectiveness in vivo in mice. Manganese-enhanced inversion recovery imaging showed an increased normalized pancreas signal in normal mice after glucose stimulation versus a saline control injection. No increase in signal intensity was observed after glucose stimulation versus saline control in diabetic mice.

12:18 875. Fuel Metabolism During Exercise in Eu- And Hyperglycemia in Subjects with Type 1 Diabetes Mellitus Michael Ith1, Stefan Jenni1, Sabin Allemann1, Christoph Oetliker1, Silvia Wuerth2, Luc Tappy3, Peter Diem1, Emanuel R. Christ1, Chris Boesch1, Christoph Stettler1 1University Bern, Bern, Switzerland; 2University Basel, Basel, Switzerland; 3University Lausanne, Lausanne, Switzerland

Little is known about the effect of blood glucose levels on muscle fuel metabolism during aerobic exercise in individuals with Type1 diabetes mellitus. The goal of the presented study therefore was to investigate muscular lipid and glycogen consumption during either eu- or hyperglycemic conditions during aerobic exercise. Two hours of cycling at an output power corresponding to 55-60% of VO2max revealed similar glycogen consumption, but higher IMCL consumption during euglycemic exercise condition coupled with a significantly lower RER. Therefore energy utilization of subjects with T1DM tends to rely on carbohydrate oxidation under hyperglycemia and shift to lipid oxidation during euglycemia.

Gray Versus White Matter: Native Image Contrast Mechanism Room 701 A 10:30-12:30 Chairs: Diana Gomez Hassan and Robert E. Watson, Jr.

10:30 876. The Molecular Basis for Gray and White Matter Contrast in Phase Imaging Kai Zhong1, Jochen Leupold2, Dominik von Elverfeldt2, Oliver Speck1 1Otto-von-Guericke University, Magdeburg, Germany; 2University Hospital Freiburg, Freiburg, Germany

Direct magnetic resonance phase images acquired at high field have been shown to yield superior gray and white matter contrast up to 10-fold higher compared to conventional magnitude images. However, the underlying contrast mechanism is not yet understood. This study demonstrates that the water macromolecule exchange is the dominant effect that determines the in vivo phase image contrast. Therefore, magnetic resonance phase imaging could be applied for in vivo studies of pathologies on a macromolecular level.

10:42 877. Using Field Simulations to Understand Susceptibility Related Phase Contrast in High Field Gradient Echo Images Andreas Schäfer1, Penny A. Gowland1, Richard Bowtell1 1University of Nottingham, Nottingham, UK

Phase images acquired at 7T, have been shown to provide enhanced grey to white matter contrast compared with modulus data and to allow the delineation of cortical sub-structure. The nature of this contrast has not been explored in detail and important questions remain about its quantitative nature and level of locality. Here, a Fourier-based method for simulating the field perturbations produced by a general magnetic susceptibility distribution have been used to explore the relationship between the form of the susceptibility distribution and phase contrast. The results have been compared with experimental data acquired at 7T from human subjects.

10:54 878. Optimization of Phase Contrast in Susceptibility Weighted Imaging at 7T Yulin Ge1, Samuel Barnes, Yingbiao Xu, Jaladhar Neelavalli, Robert I. Grossman1, E. Mark Haacke 1New York University Medical Center, New York, New York, USA

Imaging small transcereberal veins and venules is now possible using susceptibility weighted imaging at 7T. In this work, small venules within cerebral cortex are clearly identified and structures such as the arcuate fibers in the gray matter are also demonstrated using SWI filtered phase images.

11:06 879. Visualization of the Subthalamic Nuclei at High Spatial Resolution and High Contrast with Susceptibility Weighted Phase Imaging Alexander Rauscher1, Stephan Witoszynskyj2, Shannon Kolind1, Volker Coenen1, David Li1 1UBC, Vancouver, Canada; 2Friedrich Schiller Universitaet Jena, Jena, Germany

The stereotactic procedure of placing electrodes into the subthalamicnuclei (STN) to alleviate the symptoms of Parkinson disease requires areliable identification of the STNs' shape and location. This caneither be achieved by defining their position relative to landmarks orby direct targeting using imaging data that show the STN. Currently,heavily T2-weighted spin echo MR imaging is the method of choice fordirect visualization, using the iron content as a source ofcontrast. We present a fast method based on susceptibility-weighted phase imaging that allows the visualization of the STN at high spatial resolutuion with high contrast.

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11:18 880. Delineation of the Subthalamic Nucleus (STN) on High-Resolution Maps of R2* Gunther Helms1, Tabea Gringel1, Michael Knauth1, Peter Dechent1, Erck Elolf1 1Göttingen University, Göttingen, Germany

The subthalamic nucleus (STN) is the target structure for deep brain stimulation for neurosurgical treatment of Parkinson’s disease. It is notoriously difficult to detect on T1-weighted structural MRI, but exhibits a short T2* due to high iron content. Maps of R2*=1/T2* with 0.95 mm resolution were obtained using 3D multi-echo FLASH (TR = 30 ms, &#61537; = 20 , 8 bipolar echoes at TE = 2.23 to 23.2 ms, 370 Hz/pixel). The center and extension of the STN was determined in 20 healthy adults by a thresholded overlay. Marked differences to the generally accepted STN position were found.

11:30 881. High Resolution R2* Maps Reveal Laminar Structure of Human Visual Cortex in Vivo. Masaki Fukunaga1, Marta Bianciardi1, Peter van Gelderen1, Jacco A. de Zwart1, Jeff H. Duyn1 1National Institutes of Health, Bethesda, Maryland, USA

High resolution T2* weighted MRI at high field strength shows substantial contrast variation across laminae in cortical gray matter. This contrast variation is most prominent in phase images and indicates a substantial bulk susceptibility shift. In this work, we investigated whether this susceptibility shift leads to observable changes in R2*. In-vivo R2* maps obtained from human visual cortex at 7T indeed show a prominent, laminar specific R2* increase in the line of Gennari. This finding suggests that, similar to phase data, R2* maps might aid in revealing cortical laminar structure.

11:42 882. Post-Mortem MRI of Human Brain Hemispheres: Effects of Formaldehyde Fixation on T2 Relaxation Robert John Dawe1, David A. Bennett2, Julie A. Schneider2, Sunil K. Vasireddi1, Konstantinos Arfanakis1 1Illinois Institute of Technology, Chicago, Illinois, USA; 2Rush University Medical Center, Chicago, Illinois, USA

Postmortem MRI of the human brain allows histological examination of the tissue specimen following the MR scan. Correlating postmortem MR and histological results may allow the development of novel diagnostic techniques. However, the effects of fixation on the MRI properties of postmortem tissue are not well understood. In this study, five cadaveric human brain hemispheres, immersed in formaldehyde, underwent weekly MR scans for three months postmortem. In deep tissue, the T2 values initially decreased and subsequently increased to reach a plateau at approximately 3 months postmortem. In contrast, the plateau was reached within days postmortem for tissue near the surface.

11:54 883. Magnetisation Transfer Effects in an IR-TSE Study of Cortical Layers in the Area V1 Ana-Maria Oros-Peusquens1, Sandro Romanzetti1, N. Jon Shah1, Robert Turner2 1Institute of Medicine, Research Centre Juelich, Juelich, Germany; 2Max-Planck-Institute for Human Cognitive and Brain Sciences, Leipzig, Germany

Magnetization transfer effects are known to be important in the contrast of 2D-turbo-spin-echo brain images. While using 3D turbo-spin echo imaging at 3 T to identify human cortical layer structure in vivo with isotropic voxels, an apparent shortening of T1 was observed. This can only be explained by invoking a magnetization transfer effect, despite the use of thick slabs for volume imaging. Optimal 3D-TSE sequence parameters for best grey-white contrast thus require empirical determination.

12:06 884. Direct Saturation MRI: Theory and Application to Imaging Brain Iron Seth A. Smith1, 2, Jeff W.M Bulte2, Peter C.M. van Zijl1, 2 1Kennedy Krieger Institute, Baltimore, Maryland, USA; 2Johns Hopkins University, Baltimore, Maryland, USA

We show that direct water saturation can differentiate gray matter (GM) structures with different iron contents. Saturation depends on T1, T2, and the strength, length and frequency offset of RF irradiation. T2 decrease, e.g. due to presence of iron, broadens the saturation spectrum and can be selectively detected when minimizing magnetization transfer effects. A direct saturation ratio (DSR) was determined analogous to magnetization transfer ratios (MTR). DSR in GM correlated with iron concentration. We also show that DSR imaging can be used to determine T1 without influence from compartmental averaging and that T1 relaxation is largely unaffected by iron content

12:18 885. Iron as a Source of Laminar Contrast in MRI of Human Cerebral Cortex Tie-Qiang Li1, Masaki Fukunaga1, Peter van Gelderen1, Jacco de Zwart1, Steve Dodd1, Afonso Silva1, Kant Matsuda2, Bing Yao1, Karin Shmueli1, Hellmut Merkle1, Jeff Duyn1 1NINDS, Bethesda, Maryland, USA; 2NIH, Bethesda, Maryland, USA

We recently showed that resonance frequency changes induced by magnetic susceptibility variations in grey matter allow in-vivo visualization of laminar architecture with unprecedented contrast, and suggested that the contrast might be due to laminar variation in iron and / or myelin content. Here, we compare MRI scans of post-mortem brain tissues before and after chemical extraction of iron, and find that most of the intra-cortical frequency shifts are caused by tissue iron.

Sensitivity Enhancement Through Hyperpolarization of Carbon & Other Nuclei Room 701 B 10:30-12:30 Chairs: Kevin M. Brindle and John Kurhanewicz

10:30 886. Use of Hyperpolarized13C MR to Monitor Cardiiac Metabolism In Vito in Type 1 Diabetes Marie Allen Schroeder1, Lowri Elizabeth Cochlin1, Kieran Clarke1, George K. Radda1, Damian J. Tyler1 1University of Oxford, Oxford, UK

Hyperpolarized 13C MR provides the signal necessary to visualize in vivo substrate uptake and metabolism in real time. This study used hyperpolarized 1-13C-pyruvate as a metabolic tracer to detect changes in cardiac metabolism characteristic of type 1 diabetes. Specifically, a reduction in the activity of pyruvate dehydrogenase (PDH) was observed. This work represents the first instance in which PDH activity has been detected in vivo non-invasively. The ability to monitor PDH activity in vivo should provide a powerful tool for the study of disease progression and treatment in type 1 diabetes.

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10:42 887. NMR Detection of 13CO2 and [13C]Bicarbonate is Sensitive to the Duration of Reperfusion After Brief Myocardial Ischemia Matthew Merritt1, Crystal Harrison1, Charles Storey1, A. Dean Sherry1, 2, Craig Malloy1, 3 1University of Texas Southwestern Medical Center, Dallas, Texas, USA; 2University of Texas at Dallas, Richardson, Texas, USA; 3VA North Texas Healthcare System, Dallas, Texas, USA

13CO2 and [13C]bicarbonate from hyperpolarized [1-13C]pyruvate were monitored by 13C NMR in the isolated rat hearts immediately and 20 minutes after brief global ischemia. 31P NMR spectra for detecting ATP, phosphocreatine and pH were obtained every 3 minutes in parallel experiments. Immediately after ischemia, 13CO2 and [13C]bicarbonatewere not observed although the [ATP] and [phosphocreatine] were nearly normal. Twenty minutes later, the appearance of 13CO2 and [13C]bicarbonate recovered. Using multinuclear NMR, during the first 90 seconds of reperfusion pyruvate oxidation is essentially zero but recovers quickly in reversibly-injured myocardium. 13C NMR is sensitive to the duration of reperfusion.

10:54 888. Serial Hyperpolarized 13C 3D-MRSI Following Therapy in a Mouse Model of Prostate Cancer Albert P. Chen1, Robert Bok1, Vickie Zhang1, duan Xu1, Srivathsa Veeraraghavan1, Ralph E. Hurd2, Sarah J. Nelson1, John Kurhanewicz1, Daniel B. Vigneron1 1UCSF, San Francisco, California , USA; 2GE Healthcare, Menlo Park, California , USA

Using hyperpolarized 13C substrates, it has been demonstrated that tumor progression in an animal model and tumor cells response to chemo-therapy ex vivo can be monitored by MRSI/MRS studies. In this study, a transgenic mouse model of prostate cancer mice were studied serially prior and after androgen deprivation therapy using 13C MRSI with hyperpolarized 13C pyruvate as a substrate. From the preliminary results, lower tumor Lac/Pyr ratios at baseline were associated with a reduction in Lac/Pyr after therapy and a positive response to therapy. More studies are required to understand this possible correlation.

11:06 889. Imaging PH in Vivo Using Hyperpolarized 13C-Labeled Bicarbonate Ferdia Aidan Gallagher1, 2, Mikko I. Kettunen1, 2, Sam E. Day1, 2, De-en Hu1, 2, René in ‘t Zandt3, Pernille R. Jensen3, Magnus Karlsson3, Klaes Golman4, Mathilde H. Lerche3, Kevin M. Brindle1, 2 1University of Cambridge, Cambridge, UK; 2CRUK Cambridge Research Institute, Cambridge, UK; 3Imagnia, Malmö, Sweden; 4Imagnia, Sweden

Alterations in pH underlie many pathological processes and therefore there is a pressing need for techniques that could be used to measure tissue pH in the clinic. We show here that tissue pH can be imaged in vivo from the ratio of the signal intensities of hyperpolarized H13CO3

- and 13CO2 following injection of hyperpolarized H13CO3

-. The technique has shown that the average pH of a mouse tumor was significantly lower than the surrounding tissue in keeping with an acidic extracellular environment.

11:18 890. Signal Enhancement in Low-Dose Hyperpolarized 13C Imaging Using Multi-Slice FSEPSI Sequence Yi-Fen Yen1, Patrick Le Roux2, Rober Bok3, Jim Tropp1, Albert Chen3, Matthew Zierhut3, 4, Ilwoo Park3, 4, Mark Albers3, 4, Hubert Dirven5, Tim Skloss6, Jan Wolber7, Vickie Zhang3, Simon Hu3, 4, Dan Vigneron3, John Kurhanewicz3, Sarah Nelson3, Ralph Hurd1 1GE Healthcare, Menlo Park, California , USA; 2GE Healthcare, France; 3University of California, San Francisco, California , USA; 4Berkeley, California , USA; 5GE Healthcare, Oslo, Norway; 6GE Healthcare, Waukesha, USA; 7GE Healthcare, Amersham, UK

We explored the application of an FSEPSI sequence for low-dose, hyperpolarized 13C metabolic imaging. The sequence utilized a CPMG echo train to sustain the transverse magnetization of the imaging slice. The longitudinal magnetization outside of the imaging slice was remained undisturbed. A symmetric EPSI waveform centered at each spin echo was used for spectroscopic imaging. Multiple slices were acquired, each with a single-shot FSEPSI acquisition. The SNR advantage of the FSEPSI sequence was demonstrated in dog prostate spectroscopic imaging following an injection of low-dose hyperpolarized 13C-pyruvate solution.

11:30 891. How Does Dose of Hyperpolarized 13C1-Pyruvate Affect Metabolic Results in Dog Prostate? Matthew L. Zierhut1, 2, Yi-Fen Yen2, Albert P. Chen, Robert Bok, Mark Albers1, Vickie Zhang, James Tropp2, Ilwoo Park1, Daniel B. Vigneron1, John Kurhanewicz1, Ralph E. Hurd2, Sarah J. Nelson1 1UCB/UCSF, San Francisco, California , USA; 2GE Healthcare, California , USA

Varying dose levels of hyperpolarized 13C1-pyruvate were studied as a tool for investigating in-vivo 13C metabolism of dog prostate. Results suggest that pyruvate is converted into lactate at a higher rate with lower doses. Also, lactate SNR does not change significantly with 13C1-pyruvate dose.

11:42 892. Acetyl-CoA and Acetyl-Carnitine Show Organ Specific Distribution in Mice After Injection of DNP Hyperpolarized 13C1-Acetate Pernille Rose Jensen1, Rene in 't Zandt1, Magnus Karlsson1, Georg Hansson1, Sven Månsson1, Anna Gisselsson1, Mathilde Lerche1 1Imagnia AB, Malmö, Sweden

The metabolism of DNP hyperpolarized 13C1-acetate in mice reveals that acetate is a promising substrate to study metabolism in vivo. Two metabolites were identified; acetyl-CoA and acetyl-carnitine. Significant differences in the ratio between acetyl CoA and acetyl carnitine are observed by single aquisition spectra localized over the heart or liver regions. The acetyl-carnitine level is significantly higher in the heart. The conversion of acetate to acetyl carnitine via acetyl CoA can be visualized in vivo using 13C-DNP NMR, is organ specific and may be a valuable diagnostic tool for fatty acid metabolism under healthy and pathological conditions.

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11:54 893. Imaging Cancer Gene Therapy Using 13C Hyperpolarised MR Technology Yann Jamin1, Steven Reynolds2, Lynette Smyth3, Cristina Gabellieri1, Simon P. Robinson1, Caroline J. Springer3, Martin O. Leach1, Geoffrey S. Payne1, Thomas R. Eykyn1 1Institute of Cancer research and Royal Marsden NHS trust, Sutton, UK; 2Oxford Instruments Molecular Biotools Ltd, Abingdon, UK; 3Institute of Cancer Research, Sutton, UK

We report the successful hyperpolarisation using dynamic nuclear polarization (DNP) of three 13C nuclei of 3,5-Difluorobenzoylglutamic acid (3,5-DFBGlu).3,5-DFBGlu is an in vivo reporter of the enzyme Carboxypeptidase G2 (CPG2). CPG2 is used in Gene Directed Enzyme Prodrug Therapy, a promising gene therapy strategy for cancer treatment to activate non toxic prodrugs into cytotoxic DNA alkylating agents. One of the 13C nuclei combines a consequent 13C NMR chemical shift upon CPG2-mediated cleavage of 3,5-DFBGlu into 3,5-DFBA and glutamic acid with a relatively long 13C T1. The successful hyperpolarisation of 3,5-DFBGlu demonstrates the potential of 13C MRS and hyperpolarised 3,5-DFBGlu to image CPG2 activity and transgene expression in vivo.

12:06 894. Therapeutic Target Metabolism Observed Using Hyperpolarized 15N Choline Cristina Gabellieri1, Steven Reynolds2, Arnon Lavie3, Geoffrey S. Payne1, Martin O. Leach1, Thomas R. Eykyn1 1The Institute of Cancer Research, Sutton, UK; 2Oxford Instruments Molecular Biotools Ltd, Abingdon, UK; 3University of Illinois, Chicago, USA

Choline is widely used as a diagnostic marker in oncology where malignant transformations are associated with altered phospholipid metabolism. Decrease in PCho level in cancer cells and in vivo is increasingly recognised as a positive response to treatments. Here we report the real-time metabolic conversion of 15N choline – hyperpolarized by Dynamic Nuclear Polarization - to hyperpolarized 15N phosphocholine catalyzed by choline kinase. The extraordinary long lifetime of the hyperpolarized signal of both parent and daughter compounds is of the order of many minutes and shows the potential of hyperpolarized 15N choline as a novel biomarker in oncology.

12:18 895. Hyperpolarized 3He MRI Apparent Diffusion Coefficients to Derive Non-Invasive Lung Pressure-Volume Curves Andrea B. Evans1, David G. McCormack2, Roya Etemad-Rezai2, Giles E. Santyr1, Grace Parraga1 1Robarts Research Institute, London, Canada; 2The University of Western Ontario, London, Canada

Pressure-volume curves (PV-curves) of the lung reflect the global static mechanical properties of the respiratory system and yield information such as lung compliance, total lung capacity, and lung elasticity. Typically, PV-curves are generated experimentally in vivo by measuring transpulmonary pressure at various lung volumes while the patient is sedated and a volume of gas is administered to inflate the lung. This approach is invasive and uncomfortable for patients and as such, it is generally only performed on patients already mechanically ventilated which limits its use. We propose to noninvasively generate lung pressure volume-curves in patients using experimentally-derived hyperpolarized 3He magnetic resonance imaging (MRI) apparent diffusion coefficients (ADC). Experimental ADC values are used to derive alveolar/acinar size and using established mathematical models of the lung transpulmonary pressure at various volumes is derived and PV-curves can be generated. The simulated PV-curves are in good agreement with previously published data from healthy subjects and those with COPD.

Targeting RF Safety in Implants & Interventions Room 713 A/B 10:30-12:30 Chairs: Alistair J. Martin and Steffen Weiss

10:30 896. Permanent Non-Invasive Device Safety Monitoring for Clinical MRI Sascha Krueger1, Daniel Wirtz1, Dennis Glaesel1, Ingmar Graesslin1 1Philips Research Europe, Hamburg, Germany

The use of devices containing electric leads or conductive structures is associated with an inherent safety risk for the patient and the physician. The presence of a device inside a patient (e.g.pacemaker) or the necessity to use other devices for diagnosis and treatment (e.g.catheters/guidewires) is, therefore, currently often a contraindication for an MR examination. Virtually any device containing conductive parts may become unsafe and may malfunction under certain conditions. Therefore, a generic detection mechanism of unsafe situations during clinical MRI scans is proposed. Deviations from the RF demand are detected in real-time by monitoring the RF transmission during the MR imaging experiment.

10:42 897. An Optically-Coupled System for Quantitative Monitoring of MRI-Induced RF Currents Into Long Conductors Marta Gaia Zanchi1, Ross Venook2, John Mark Pauly1, Greig Scott1 1Stanford University, Stanford, California , USA; 2Advanced Bionics, Sylmar, California , USA

MRI-induced RF currents in interventional devices pose safety risks that cannot be reliably predicted. We have developed and validated an optically-coupled system capable of quantitatively monitoring in real-time the RF currents induced in long conductors. We have tested it in a birdcage RF safety platform with cable-traps and Q-spoiling loads that reduce the RF currents.

10:54 898. Monitoring Induced Currents on Long Conductive Structures During MRI Ross D. Venook1, 2, William R. Overall1, Kim Shultz1, Steven Conolly3, John M. Pauly1, Greig C. Scott1 1Stanford University, Stanford, California , USA; 2Boston Scientific, Burlingame, California , USA; 3U.C. Berkeley, Berkeley, California , USA

This abstract presents an image-based method for measuring induced axial RF currents on a long conductive structure during an MRI experiment. Extensions of this method represent a way to verify and monitor safety of certain devices and guidewires during an MRI procedure.

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11:06 899. Measuring RF-Induced Currents Inside Implants: Impact of Device Configuration on MRI Safety of Cardiac Pacemaker Leads Peter Nordbeck1, 2, Ingo Weiss2, Philipp Ehses1, Marcus Warmuth1, Florian Fidler3, Peter M. Jakob1, 3, Mark E. Ladd4, Harald H. Quick4, Wolfgang R. Bauer1 1University of Würzburg, Würzburg, Germany; 2Biotronik GmbH & Co. KG, Berlin, Germany; 3Research Center Magnetic Resonance Bavaria, Würzburg, Germany; 4University of Duisburg-Essen, Essen, Germany

RF-related heating of elongated conductive implants such as cardiac pacemaker leads is a serious concern in magnetic resonance imaging (MRI). The implant configuration has been shown to be an important factor in the amount of induced heating, but this issue is still poorly understood, possibly because temperature measurements are very time consuming and particularly vulnerable to positioning errors of the probes. In this study, the electric currents induced inside the implant were measured and correlated to implant heating. This approach allows for fast, systematic and reproducible investigation of the impact of a cardiac implant’s configuration on MRI-related heating effects.

11:18 900. The Effect of Lead Length on Lead Tip Heating in Orphan Leads Verses Leads Connected to Pacemakers at 1.5T Deborah Anne Langman1, Mayil Krishnam1, Noel G. Boyle1, John Paul Finn1 1UCLA, Los Angeles, California , USA

Current safety guidelines label implanted pacemakers as a contraindication for MRI scanning due in part to risks of tissue damage from pacemaker lead tip heating. The goal of this research was to explore the lead tip heating in orphan pacemaker leads compared to leads connected to pacemakers at 1.5T. For clinical lead lengths on the order of 40-57cm the lead tip heating will be worse for capped orphan leads. For shorter lead lengths the resonance effect diminishes lead tip heating when the lead is capped, however heating increases when the pacemaker is connected. It is therefore important to consider the length of the lead implanted when comparing safety of orphan leads verses leads connected to pacemakers.

11:30 901. Clinical Trial to Evaluate Pacemaker Safety and Efficacy in MRI Environment: Device and Study Design Emanual Kanal1, Torsten Sommer2, David Bello3, Roger Luenchinger4, Richard Sutton5, Bruce Wilkoff6 1UPMC Presbyterian, Pittsburgh, Pennsylvania, USA; 2University of Bonn, Bonn, Germany; 3Mid-Florida Cardiology Specialists, Orlando, Florida, USA; 4University Hospital, Zurich, Switzerland; 5St. Mary's Hospital, London, UK; 6Cleveland Clinical Foundation, Cleveland, Ohio, USA

Up to 75% of pacemaker patients need an MRI during the life-time of the pacemaker, therefore MRI-pacemaker compatibility is a significant need. A pacemaker system has been designed and pre-clinically tested for MRI compatibility in a controlled environment. The new pacemaker system is designed to minimize lead tip heating and induced energy on leads. A pacemaker feature also eliminates the impact of MRI-generated electrical noise. A randomized clinical trial has started in 2007 to enroll 470 patients to evaluate safety and efficacy of the pacemaker system in an MRI environment. Patients are randomized to receive MRI or no MRI scan.

11:42 902. A Combined Approach to Assessing Safety of Depth Electrodes and Microwires at 3 Tesla Debra S. Strick1, Mark S. Cohen, Jack W. Judy, Frank G. Shellock 1University of California Los Angeles, Westwood, USA

Implants inadvertently acting as antenna can cause dangerous levels of MR-related heating. The resultant heating can greatly vary due to the non-linear behavior of structures near resonance. We combine heating experiments with characterization of resonant frequency profiles to minimize the uncertainty of safety characterization for a depth electrode and microwire array at 3-Tesla.

11:54 903. Experimental and Numerical Determination of SAR and Temperature Distribution of a Human Endorectal Coil for MR Imaging of the Prostate at 7T Andreas K. Bitz1, Dennis W.J. Klomp2, Mark E. Ladd1 1Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen, Germany; 2Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands

Compliance testing of a transmit and receive endorectal loop coil with respect to the SAR and temperature limits given in the IEC guidelines is performed by numerical calculation of the RF field and SAR distribution as well as experimental temperature measurements in a phantom and in the human prostate in vivo. The results show that for a maximum permissible time-averaged power of 0.76 W, the proposed endorectal coil complies with the SAR and temperature limits given in the IEC guidelines.

12:06 904. Whole Shaft Visibility for Polymer-Based Active IMRI Catheters Using Hybrid Braided Tubes Ozgur Kocaturk1, Ann Kim1, Michael A. Guttman1, Anthony Faranesh1, Andrew J. Derbyshire1, Kanishka Ratnayaka1, Robert J. Lederman1 1National Institutes of Health, Bethesda, Maryland, USA

For MR-guided interventional devices, visualization of the tip and shaft is essential for safe tracking during minimally invasive procedures. Hybrid coaxial braided tubes were implemented into the polymer-based catheter to construct a monopole antenna. Copper wires in the braiding resulted in acceptable RF transmission over the designed monopole stub, while nitinol wires lent mechanical stability to the catheter. Two distal loop coils were also implemented into the catheter body to visualize the tip and its orientation. Good visibility of the tip and whole shaft was observed in vivo and in vitro real time scanning. Torquability and pushability remained unaffected.

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12:18 905. Preclinical Evaluation of a Novel Fiber Compound MR Guide Wire Nils A. Kraemer1, Sascha Krueger2, Sebastian Schmitz3, Marita Linssen4, Heinz Schade5, Steffen Weiss2, Rolf W. Guenther1, Arno Buecker6, Gabriele A. Krombach1 1RWTH Aachen, Aachen, Germany; 2Philipps Research Europe, Hamburg, Germany; 3Fraunhofer Institute for Production Technology, Aachen, Germany; 4Hemoteq GmbH, Wuerselen, Germany; 5Andramed GmbH, Reutlingen, Germany; 6University Clinic Saarland, Homburg, Germany

An MR-conditional guide wire (GW) was evaluated in an animal model. The GW consists of a fiber glass compound with an Nitinol tip. Iron powder within the compound and iron markings improve MR visibility. Using real time MRI-guidance with balanced-SSFP sequences, various MR-interventions were performed (stent placement, embolization or direct MR angiography). Time to reach the target, induced artifacts and handling were assessed. The GW was clearly depictable on real time MRI. The GW allowed reaching all target vessels, and all interventions were completed successfully.

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TRADITIONAL POSTERS Vascular Compliance Hall D Monday 14:00-16:00

906. In Vivo Transit Time MR-Measurements of Pulse Wave Velocity in the Murine Aorta at 17.6 Tesla Marco Parczyk1, Volker Herold1, Gert Klug1, Thomas Schulze-Till1, Wolfgang Bauer1, Eberhard Rommel1, Peter Jakob1 1University of Wuerzburg, Wuerzburg, Germany

Aortic stiffness increases in an early state of arteriosclerosis, assessable by pulse wave velocity (PWV) MR-measurements. Up to now only studies in larger animals and humans have been reported in literature. The feasibility of in vivo PWV MR-measurements by two non-invasive MR-imaging techniques is presented. Because pulse wave and flow velocities are similar to velocities in humans, but dimensions are about 20-times smaller, the challenges in this project were especially the high temporal and spatial resolutions needed.

907. In Vivo Measurement of Local Pulse-Wave Velocity in Mice with MRI at 17.6 T Volker Herold1, Gert Klug1, Marco Parczyk1, Christian Ziener1, Thomas Weber1, Susanta Sarkar2, Wolfgang Rudof Bauer1, Eberhard Rommel1, Peter Michael Jakob1 1University of Wuerzburg, Wuerzburg, Germany; 2GlaxoSmithKline (GSK), King of Prussia, Pennsylvania, USA

Pulse wave velocity (PWV) is an important parameter for the evaluation of the arterial stiffness and cardiovascular risk. Several diseases such as hypertension and arteriosclerosis are associated with vascular remodeling and arterial stiffening. Mouse models of human diseases are increasingly used to investigate patho-physiological mechanisms of the cardiovascular system. A non invasive method is presented to assess local PWV in the ascending and descending aorta of mice with MR-Microscopy at 17.6 T. The results demonstrated the feasibility of high field MR microscopy to quantify local pulse wave velocity as a measure of local aortic stiffness.

908. Carotid Wall Shear Rate Measured with Spiral Fourier Velocity Encoding Joao Luiz Azevedo de Carvalho1, Jon Fredrik Nielsen1, Krishna S. Nayak1 1University of Southern California, Los Angeles, California , USA

Fourier velocity encoding (FVE) has been proposed as a method for non-invasively measuring fluid shear rate and hence vascular wall shear stress, an important factor implicated in atherogenesis. The scan-time of 2DFT FVE is prohibitively long for clinical use, but the recently introduced spiral FVE method shows promise as it is substantially faster. In this work, we investigate the feasibility of using spiral FVE for estimating shear rates near the carotid artery walls in clinically practical scan times. We present: (1) a phantom validation of spiral FVE against high-resolution 2DFT phase contrast; (2) evaluation of resolution requirements; (3) in vivo demonstration.

909. Intracranial Compliance and Pressure Measurement Based on MR Flow Quantification and Brain Circulation Model Circuit: Sensitivity to Hyperventilation and Hydrocephalus Kagayaki Kuroda1, Kosuke Maruhashi1, Moyuru Ohya1, Masatoshi Honda2, Hideki Atsumi3, Koichi Oshio4, Mitsunori Matsumae3 1Tokai University, Hiratsuka, Japan; 2Tokai University Hospital, Isehara, Japan; 3Tokai University, Isehara, Japan; 4Keio University, Shinanomachi, Japan

A noninvasive technique to evaluate brain compliance index (BCI) and intracranical pressure index (ICPI) based on MR flow quantification and an inverse analysis of brain-circulation-equivalent electrical circuits was developed. The technique was applied to healthy volunteers (N = 6) with normal breathing and hyperventilation during scanning. The BCI significantly decrease with hyperventilation in 5 volunteers. The technique was also applied to patients (N = 3) with hydrocephalus. Both BCI and ICPI were significantly lower in those patients than in the normal volunteers. These results indicated that the technique is sensitive to the change or abnormality of the brain physical properties.

910. Compliance and Anatomy of the Neo-Aorta in Children with Hypoplastic Left Heart Syndrome (HLHS) Michael Helle1, 2, Inga Voges1, Michael Jerosch-Herold2, Christopher Hart1, Traudel Hansen1, Hans-Heiner Kramer1, Carsten Rickers1 1Christian-Albrechts-Universität, Kiel, Germany; 2Brigham & Women's Hospital, Boston, USA

The purpose of this study was to assess aortic anatomy and aortic compliance (AC) in children with hypoplastic left heart syndrome (HLHS) using cardiac MRI at 3 Tesla.Cine MRI and contrast enhanced time-resolved MR-angiography were performed in all patients for measuring selected diameters of the neo-aorta and for a selected determination of the AC.Diameters of the aortic root, the ascending aorta and the aortic arch were significantly increased. We found a significant smaller aortic isthmus in children with HLHS, whereas the dimensions of the descending aorta were not significantly changed. AC was decreased in the ascending aorta as well as the aortic arch.

911. Quantitative 2D and 3D Phase Contrast MRI: Optimized Analysis of Blood Flow and Vessel Wall Parameters Aurélien F. Stalder1, Max F. Russe1, Alex Frydrychowicz1, Jelena Bock1, Jürgen Hennig1, Michael Markl1 1University Hospital Freiburg, Freiburg, Germany

The purpose of this work was the development of an optimized quantitative analysis method in order to derive flow and wall parameters from CINE phase contrast (PC) MR data. The data analysis strategy combines “Green’s theorem” and B-spline interpolation with their finite difference property to provide an optimal quantification of several blood flow and vessel wall parameters. Calculation of the local blood flow velocity derivatives onto the vessel contour using B-spline interpolation allowed a direct and reliable estimate of time-resolved segmental WSS vectors independent of any restrictive global assumptions regarding the flow profile.

Poster Sessions

177

MRA: Other Techniques Hall D Tuesday 13:30-15:30

912. High Flow Fistula Imaging: A Study Comparing Bright-Blood and Black-Blood Approaches Anders Niemann1, Samuel Alberg Kock1, Steffen Ringgaard1, Ernst Torben Fründ2, Steffen Ellebæk Petersen, Michael Hasenkam1 1Aarhus University Hospital Skejby, Aarhus N, Denmark; 2Aalborg Hospital, Aarhus University Hospital , Aalborg, Denmark

To generate images suitable for segmentation to be used in CFD simulation of blood flow in fistulas two methods were examined and evaluated. The scans were performed on an in vitro phantom. A mean high steady flow was applied to the inlets of the phantom to simulate the chaotic and turbulent flow in fistulas. Bright blood yielded fast images with excellent image quality except in the fistula chamber, a location with severely turbulent and chaotic flow. Black blood, though slower, yielded excellent image quality everywhere, also in the fistula chamber.

913. Evaluation of the Thoracic Aorta with Gated CE-MRA: Technical Feasibility and Comparison with Ungated Studies Phillip Young1, Eric Williamson1, Maggie Fung2, David Stanley2, James Glockner1 1Mayo Clinic, Rochester, USA; 2GE Healthcare, Waukesha, Wisconsin, USA

Conventional CE-MRA of the thoracic aorta is limited by motion at the aortic root. We describe our experience with 2 and 4 phase gated CE-MRA sequences, with particular attention to improved visualization of the sinotubular junction, aortic arch vessels, and LCA. Our experience indicates technical feasibility, with markedly improved visualization of the aortic root and proximal coronary arteries resulting from the improved temporal resolution. Prolonged image acquisition and reconstruction times caused limitations in some patients. However, all gated CE-MRA sequences offered improved image quality when compared with prior ungated studies. Gated CE-MRA of the thoracic aorta is a promising technique.

914. Real Time Self Tracking of Contrast Kinetics for Whole Heart Coronary Artery Magnetic Resonance Angiography Himanshu V. Bhat1, Peng Lai1, Debiao Li1 1Northwestern University, Chicago, Illinois, USA

Contrast enhanced coronary artery magnetic resonance angiography at 3T with slow infusion of contrast agent has recently shown very promising results. In this work a new method for tracking the contrast enhancement during slow infusion of contrast agent is proposed and validated. This method is based on acquiring an extra projection of the heart during imaging and gives an accurate representation of the contrast enhancement. The method is embedded in the high resolution segmented IR-FLASH sequence and has a host of potential applications.

915. Intra-Thoracic Blood Volume Measurement by Contrast Magnetic Resonance Imaging Massimo Mischi1, Harrie C. M. van den Bosch, Jacques A. den Boer, Jan Verwoerd, Rene` J. Grouls, Cathinka H. Peels, Hendricus H. Korsten 1Eindhoven University of Technology, Eindhoven, Netherlands

The intra-thoracic blood volume (ITBV) is related to the cardiac preload and the left ventricular function. A minimally invasive method for the ITBV measurement by contrast magnetic resonance imaging (MRI) is presented and validated in vitro. The clinical feasibility of the method is also shown. A bolus of a paramagnetic agent is intravenously injected and detected by MRI in the right and left ventricles. The analysis of the measured indicator dilution curves by suitable models, combined with the flow measurement by phase contrast angiography, permits the estimation of the ITBV. The results are accurate and motivate further investigations.

916. 7D Spiral Phase Contrast MRI for the Comprehensive Assessment of Aortic Flow in Mice Robert L. Janiczek1, Brett R. Blackman1, R. Jack Roy1, Scott T. Acton1, Craig H. Meyer1, Frederick H. Epstein1 1University of Virginia, Charlottesville, Virginia , USA

The ability to assess wall shear stress (WSS) in genetically-engineered mice would enable the investigation of the roles of individual genes in the relationship between WSS and atherosclerosis. The ideal method would cover large regions of the vessel of interest, directly measure WSS, and have high temporal resolution. A 3D stack-of-spirals PC sequence was developed to acquire 7D data of the mouse aorta. High resolution geometry was obtained of the abdominal aorta along with all three-components of velocity throughout systole.

Non-Contrast Enhanced MRA Hall D Wednesday 13:30-15:30

917. Adamkiewicz Artery Using Non-Contrast Time-SLIP with 3D Balanced SSFP yuichi yamashita1, Takao Yamamoto, Syuhei Takemoto, Ayako Ninomiya, Ikuo Aoki, Masao Yui 1Toshiba Medical Systems Corporation, Tokyo, Japan

Adamkiewicz artery is am important artery to identify before the surgery in patients with aortic disease. Present studies reported that CTA and CE MRA show visualization of the Adamkiewicz artery. An arterial spin labeling, time-spatial labeling inversion pulse (time-SLIP) allows visualization of marked blood vessels without use of contrast medium. Combination of time-SLIP with 3D balanced SSFP (bSSFP) allows depiction of marked blood traveled within an inversion time (TI) range with good contrast. In this study, we have investigated the technique to depict the Adamkiewicz artery by adjusting TI and the position of a free-hand tag to mark the vessel.

Poster Sessions

178

918. Time Spatial Labeling Pulse Sequence for the Screening of Renal Artery Stenosis: A Non Contrast Enhanced Approach Isabelle Parienty1 1Bois de Verrières Medical Imaging Center, Antony, France

Renal Artery Stenosis (RAS) is the major cause of renovascular hypertension and an important cause of chronic renal insufficiency and end-stage renal disease. Until recently, Contrast Enhanced MRA (CE-MRA) was considered a non-invasive and totally safe technique for the evaluation of RAS. The recent link between gadolinium and nephrogenic systemic fibrosis (NSF) in patient with renal insufficiency ranked down CE-MRA to the least invasive technique with a considerable risk for patients with RAS. In this work we evaluated the clinical usefulness of a totally safe new commercially available non-enhanced MRA technique, Time-SLIP, in the screening of RAS.

919. Automatic Detection of Systolic and Diastolic Phase for NATIVE Alto Stemmer1, Peter Schmitt1, Berthold Kiefer1 1Siemens Medical Solutions, Erlangen, Germany

Blood flow synchronized 3D turbo spin echo imaging can be used for non contrast enhanced peripheral MRA. The optimal trigger times are often determined in a 2D scout scan, which acquires multiple single shot images in various cardiac phases. Here we introduce a technique that evaluates the scout images by means of image processing methods.

920. Non-Contrast Pulmonary Vein Angiography Using Off-Resonance RF Excitation Reza Nezafat1, Christian Stoeck1, Prity Bengani2, Dana C. Peters1, Thomas Hauser1, Neil M. Rofsky1, Warren J. Manning1 1Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA; 2Boston Univeristy, Boston, Massachusetts, USA

Atrial fibrillation is a disorder afflicting over 2 million Americans with higher likelihood occurrence with increasing age. Radiofrequency pulmonary veins isolation is commonly used to treat patients with AF. For these patients evaluation of PV anatomy is essential in pre-procedural planning and post-procedural assessment of this treatment. Today, contrast-enhanced MR angiography is commonly used to evaluate PVs in RF ablation. In today’s clinical practice, PV image acquisition is performed during first pass injection of gadolinium contrast or with computed tomography and iodinated contrast. However, contrast enhanced approaches have adverse safety implications for patients with renal insufficiency. In this study, we investigated the use of off-resonance RF excitation demonstrate the blood in the pulmonary veins without exogenous contrast media.

921. Free-Breathing Non-Contrast-Enhanced Three-Dimensional Steady-State Free Precession MR Angiography for the Detection of Thoracic Aortic Disease and Simultaneous Visualization of Coronary and Internal Thoracic Arteries Yasuo Amano1, Katsuya Takahama1, Shinichiro Kumita1 1Nippon Medical School, Tokyo, Japan

The purpose of this study was to evaluate the usefulness of free-breathing non-contrast-enhanced 3D SSFP MR angiography for the detection of the thoracic aortic diseases and simultaneous visualization of internal thoracic and coronary arteries. The 3D SSFP imaging was combined with cardiac and navigator-gating techniques, and T2-prepared and fat-suppression pulses. Coronal contrast-enhanced 3D MR angiography was performed for comparison. High correlation was observed for diameter of the thoracic aorta between the two MR angiography techniques. Accurate diagnoses of the diseases were made in most patients. Internal thoracic and coronary arteries were visualized better by free-breathing non-contrast-enhanced 3D MR angiography.

922. STAR and STARBURST for Combined Flow Dependent and Flow Independent Carotid MR Angiography Ioannis Koktzoglou1, 2, Robert R. Edelman1, 2 1Evanston Northwestern Healthcare, Evanston, Illinois, USA; 2Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA

In the evaluation of extracranial carotid artery disease, non-contrast MR angiography must be improved to compete with contrast-enhanced examinations. We present the combination STAR and STARBURST, flow dependent and flow independent sequences capable of generating high quality carotid MR angiograms without the need for contrast material.

923. Clinical Application of Non-Contrast Enhanced MRA at 1.5T to Peripheral Arteries in Patients with Obstructive Vascular Disease Isabelle Parienty1 1Bois de Verrieres Medical Imaging Center, Antony, France

CT Angiography and contrast-enhanced MR Angiography (CE-MRA) techniques have become widely established and are nowadays used in routine clinical exploration of peripheral, lower extremities and renal arteries. However, in-patient with renal dysfunction, there is a growing amount of evidence against the systematic use of gadolinium-based CE-MRA as it has been linked to the development of nephrogenic systemic fibrosis. In this work, we investigated the reliability of the commercially available non-contrast enhanced MRA technique: Fresh blood imaging (FBI) in our clinical setting to explore patients with obstructive vascular disease.

924. Applying the BSSFP Dixon Method for Fat-Water Separation to Non-Contrast-Enhanced MRA in the Legs Randall B. Stafford1, 2, Mohammad Sabati1, 2, Michael J. Haakstad2, Houman Mahallati1, 2, Richard Frayne1, 2 1University of Calgary, Calgary, Canada; 2Foothills Medical Centre, Calgary Health Region, Calgary, Canada

Huang et al. showed that the balanced steady-state free precession Dixon method provides good fat-water separation. Separation is achieved by adjusting the centre frequency to collect two images where fat and water are in-phase and opposed-phase, respectively. Adding these two images results in a fat-suppressed water-only image. We hypothesize that this technique can perform fast 3D non-contrast enhanced (NCE) MR angiography (MRA). We collected 3D image volumes in the legs of five healthy volunteers using this method. Good vessel conspicuity was found in our water-only image volumes. We conclude that this technique has the potential for non-contrast-enhanced MR angiography.

Poster Sessions

179

925. Accelerating Phase Contrast MRA by SPEED Using Efficient Multiple Acquisitions and Shared Information Zheng Chang1, Qing-San Xiang2, Jim Ji3 1Duke University, Durham, USA; 2University of British Columbia, Vancouver, Canada; 3Texas A&M University, College Station, Texas, USA

The efficient multiple acquisition technique using shared spatial information by Skipped Phase Encoding and Edge Deghosting (SPEED) has been successfully demonstrated in water-fat imaging with double acquisitions. In this work, the technique is further used to accelerate phase-contrast (PC) MRA. Multiple acquisitions in PC-MRA share similar spatial information. By making use of the shared information, PC-MRA is accelerated by SPEED with factors greater than that achievable for a single acquisition. In this work, a PC-MRA study with two acquisitions is accelerated by a factor of nearly 2, reducing scan time to that of about one acquisition.

926. Axial 2D TOF-Venography with Continuously Moving Table Acquisitions Sandra Huff1, Dominik Paul1, Michael Markl1, Ute Ludwig1 1University Hospital Freiburg, Freiburg, Germany

Time-of-Flight MR-Angiography (TOF-MRA) allows for vessel imaging without the application of contrast agents. A difference method for TOF-MRA of an extended Field of View is presented while the patient table is continuously moved during data acquisition. The peripheral veins from the bifurcation to the feet were imaged using the proposed acquisition technique. Furthermore an optimal flip angle was determined resulting in a high venous signal for the chosen sequence parameters.

927. 3D Dark Blood MR Angiography of the Thoracic Vessels Yiu-Cho Chung1, Stephen Cook, Jaeseok Park2, Marshall Winner, Renate Jerecic, Orlando Simonetti 1Siemens Medical Solutions USA, Inc., Columbus, USA; 2Siemens Medical Solutions, Germany

Followup of patients with aortopathy and congenital heart diseases post-surgery is difficult with current 3D MR angiographic techniques because of their sensitivity to susceptibility artifacts from metallic stents commonly found in these patients. The conventional 2D turbo spin echo techniques suffer from partial volume effects, long scan time and difficult slice positioning in patients with congenital diseases. We propose a new 3D turbo spin echo technique that provides isotropic, high resolution dark blood thoracic MR angiography. The technique has reduced susceptibility artifacts and was found to improve visualization of vessel patency in patients with aortic stents.

928. Non-Contrast, Free Breathing 3D SSFP MR Angiography of Pulmonary Veins: Initial Experience Aparna Singhal1, Anderanik Tomasian1, ALex Sassani2, Vibhas Deshpande2, Gerhard Laub2, J. Paul Finn2, Stefan Ruehm2, Mayil S. Krishnam3 1UCLA, Los Angeles, USA; 2UCLA, USA; 3UCLA, Los ANgeles, USA

We sought to investigate the feasibility of non-contrast, free breathing 3D-SSFP MR Angiography for pulmonary veins evaluation and to correlate with conventional contrast-enhanced MRA. 3D-SSFP MRA provides sufficient vascular delineation and SNR, CNR to support confident evaluation of pulmonary veins.

929. A Method for Removing Fluid-Bearing Voxels from STARBURST MR Angiographic Images Ioannis Koktzoglou1, 2, Robert R. Edelman1, 2 1Evanston Northwestern Healthcare, Evanston, Illinois, USA; 2Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA

STARBURST is a newly proposed method for creating high quality flow-independent angiograms. When acquired with a trueFISP image readout, the STARBURST technique enhances signals from fluids that may obscure view of the angiogram. We present a method for identifying and automatically removing fluid-bearing voxels.

930. Fast Spin-Labeled Projectional Carotid MR Angiography Ioannis Koktzoglou1, 2, Robert R. Edelman1, 2 1Evanston Northwestern Healthcare, Evanston, Illinois, USA; 2Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA

Non-contrast methods for angiography may reduce procedural cost and risk of adverse reactions to contrast material. We present an arterial spin-labeled technique that allows for projectional carotid MR angiography in twenty seconds.

931. Investigation of Background Suppression Strategies in Interactive Fresh Blood Imaging Pauline Wong1, Martin John Graves1, David John Lomas1 1University of Cambridge and Addenbrooke's Hospital, Cambridge, UK

Background suppression in subtraction MR angiography can be a problem when the TR of two acquisitions are different, causing unequal tissue signal which results in an angiogram with high background signal. This is encountered in interactive FBI where triggering occurs alternately in systole and diastole at short TR. Five tissue suppression strategies are investigated to improve the flow contrast in this case: Magnetisation Transfer (MT) prep, Projection dephaser, Inversion Recovery prep, Variable Refocusing Flip Train and single-triggered Fixed TR. Preliminary results suggest that MT, IR, variable flip and Fixed TR can be optimised for background suppression in interactive subtraction angiography.

Poster Sessions

180

932. “Inflow“ Renal MR-Angiography with Steady-State Free-Precession and Slab-Selective Spin Inversion: Intraindividual Comparison with Ce-MRA in Patients Marcus Katoh1, Jan Weidner2, Arno Buecker1, Matthias Stuber3, Rolf W. Gunther2, Elmar Spuentrup2 1University Hospital Saarland, Homburg, Germany; 2RWTH Aachen University Hospital, Aachen, Germany; 3Johns Hopkins University Medical School, Baltimore, Maryland, USA

The reliability of a previously introduced inversion-prepared renal MRA technique was evaluated in patients. 103 renal arteries in 45 patients were investigated on a 1.5 T whole-body MR-system using a free-breathing navigator-gated and cardiac-triggered 3D steady-state free-precession sequence with a preceding slab-selective inversion pulse (inflow-MRA). For comparison contrast-enhanced MRA (ce-MRA) was performed. Images were evaluated in terms of artifacts and visualization of the renal arteries. In addition, the stenosis grade was assessed. Inflow-MRA yielded sonsistently good image quality and showed excellent correlation to ce-MRA with respect to the assessment of the stenosis grade without the need for contrast medium application or breath-hold.

933. Non Contrast Enhanced MRA of the Lower Extremities Using an ECG-Gated Variable Flip Angle 3D Fast Spin Echo Sequence Ruth P. Lim1, Andrew D. Hardie1, Elizabeth M. Hecht1, Danny C. Kim1, Jian Xu2, Pippa Storey1, Thomas P. Mulholland1, Sooah Kim1, James S. Babb1, Vivian S. Lee1 1NYU Medical Center, New York, USA; 2Siemens Medical Solutions, New York, USA

The association of Nephrogenic Systemic Fibrosis with gadolinium chelates has increased interest in the development of clinically viable non contrast MRA techniques. We describe our initial clinical experience with an ECG-gated variable flip angle fast spin echo technique to image the lower limb vasculature. This has the advantage of shorter interecho spacing and a shorter acquisition window compared with a previously described ECG-gated HASTE MRA technique, with improved spatial resolution and timing of systolic and diastolic acquisitions. The technique is feasible with a high negative predictive value, however further optimization includes addressing B1 inhomogeneity.

934. Comparison of Image Reconstruction Algorithms for the Depiction of Vessel Anatomy in PC VIPR Datasets Ashley Gould Anderson1, Kevin M. Johnson1, Jelena Bock2, Michael Markl2, Oliver Wieben1 1University of Wisconsin, Madison, Wisconsin, USA; 2University Hospital Freiburg, Freiburg, Germany

This study compares eight algorithms for the generation of angiograms from cine phase contrast VIPR imaging, a truly 3D radial trajectory with radial undersampling. The motivation for this investigation is based on the renewed interest in non-contrast enhanced MRA methods and the need for accurate depiction of vessel anatomy and boundaries for clinical evaluations and for the direct derivation of hemodynamic parameters such as wall shear stress and trans-stenotic pressure gradients from the velocity vector fields.

Coronary MRA Hall D Thursday 13:30-15:30

935. Coronary Magnetic Resonance Angiography Using Non Spatially Selective Navigator Excitations at 3T Harsh K. Agarwal1, Khaled Z. Abd-Elmoniem1, Michael Schär1, 2, Sebastian Kelle1, Matthias Stuber1, Jerry L. Prince1 1Johns Hopkins University, Baltimore, Maryland, USA; 2Phillips Medical System, Best, Netherlands

B0 inhomogeneity, reduced T2* and off-resonant fat excitation may adversely affect the performance of 2D selective navigator technology, particularly at higher magnetic field strength. Furthermore, localization of a 2D selective navigator is user dependent and time consuming. A navigator technique which uses non-spatially selective excitation in conjunction with local surface coil navigator signal reception is proposed to circumvent the aforementioned issues.

936. Contrast-Enhanced Whole-Heart Coronary MR Angiography at 3.0 T: Comparison to Steady-State Free Precession Imaging at 1.5 T Xin Liu1, Xiaoming Bi, Nondas Leloudas, Renate Jerecic, James C. Carr, Debiao Li 1Northwestern University, Chicago, Illinois, USA

To compare contrast-enhanced whole-heart coronary MRA at 3.0T and steady-state free precession imaging at 1.5 T, 11 healthy volunteers underwent both 3.0 T and 1.5 T coronary MRA using 3D FLASH with slow infusion of MultiHance and 3D TrueFISP, respectively. SNR, CNR, image quality, and coverage of coronary segments were analyzed and compared statistically. Contrast-enhanced whole-heart coronary MRA at 3.0 T demonstrated higher CNR, less acquisition time, and better depiction of coronary segments compared to non-contrast SSFP coronary MRA at 1.5 T.

937. Time-Resolved Contrast-Enhanced Coronary MRA with HYPR PR: A Feasibility Study Lan Ge1, Xiaoming Bi1, Peng Lai1, Hua Peng1, Andrew Larson1, Debiao Li1 1Northwestern University, Chicago, Illinois, USA

During contrast-enhanced coronary MRA, the blood signal changes during the contrast injection time will result in image artifacts, blurring and relatively low SNR, when the k-space segments from different cardiac cycles are combined to reconstruct the final image as ¡ time-averaged¡±. Thus, it is important to acquire data during maximal blood signal enhancement from firstmpass, therefore requiring relatively high temporal resolution. This work demonstrated the feasibility of HYPR PR for time-resolved, contrast-enhanced coronary MRA with an increased temporal resolution. HYPR processed coronary artery images around the time of peak blood signal enhancement significantly improved CNR and suppressed artifacts compared to conventional composite images.

938. "One-Stop Shop" MRI of Coronary Heart Disease at 3T: Technical Feasibility Lan Ge1, Aya Kino1, Xiaoming Bi2, Xin Liu1, Natasha Berg1, Renate Jerecic2, James Carr1, Debiao Li1 1Northwestern University, Chicago, Illinois, USA; 2Siemens Medical Solutions, Chicago, Illinois, USA

Cardiac MRI is a promising tool to detect and evaluate myocardial ischemic disease. Various MRI techniques have been developed, including functional cine scan, first pass myocardial perfusion (FPMP), coronary MRA, and delayed enhancement imaging. Nevertheless, these techniques have not been applied in the same imaging session for a comprehensive examination. The study demonstrated the feasibility of a comprehensive protocol ¡ One Stop Shop¡± for cardiac MRI at 3T. The ¡ one stop shop¡± cardiac MRI was successfully acquired in 4 volunteers with an average time of 43 minutes.

Poster Sessions

181

939. Whole-Heart Magnetic Resonance Coronary Angiography (WH MRCA) with Visual Feedback for Use in a Clinical Setting Shigehide Kuhara1, Tomohisa Okada2, Shotaro Kanao2, Ayako Ninomiya1, Saori Satou1, Toshikazu Kamae2, Kimio Goto2, Kaori Togashi2 1Toshiba Medical Systems, Otawara-shi, Japan; 2Kyoto University Hospital, Kyoto, Japan

We have developed a visual feedback (VFB) system that displays the breathing level to the patient, thus permitting the patient to adjust his or her breathing level. The present study was undertaken to investigate the usefulness of the VFB system in WH MRCA studies, aiming to perform abdominal band-free examinations for clinical use.Using the VFB system, WH MRCA can be performed with less difficulty and without prolonging the scan time, and, in particular, multi-breath-hold WH MRCA with VFB provides the best image quality in the shortest practical time.

940. Contrast Enhanced Coronary Artery Imaging in a Breath-Hold at 3 Tesla Using 3D Segmented EPI: A Feasibility Study Himanshu V. Bhat1, Sven Zuehlsdorff2, Xiaoming Bi2, Renate Jerecic2, Debiao Li1 1Northwestern University, Chicago, Illinois, USA; 2Siemens Medical Solutions, Chicago, Illinois, USA

Contrast enhanced coronary artery magnetic resonance angiography (CMRA) at 3T has recently shown very promising results. Imaging time on the order of five minutes was reported for a whole heart acquisition. Further reduction of the imaging time is required to make CMRA more robust and clinically applicable. Segmented EPI is a method which can be exploited to provide a significant speed gain for CMRA and has previously been reported at 1.5T. In this work the feasibility of 3D segmented EPI for breath-hold high resolution CMRA at 3T has been shown. Segmented EPI is a promising technique for contrast enhanced coronary artery imaging at 3T.

941. Whole-Heart Coronary Angiography at Isotropic Spatial Resolution: High SENSE Acceleration at 3T Utilizing a 32 Element Cardiac Receive Coil Axel Bornstedt1, Vinzenz Hombach1, Marc Kouwenhoven, Volker Rasche1 1University of Ulm, Ulm, Germany

Possible improvement of image acquisition time for whole-heart coronary angiography at isotropic spatial resolution by application of a 32-element cardiac coil is presented. It is shown that parallel imaging factors of up to 7.5 can be applied without severe image degradation.

942. NMR Signals from Hyperpolarized Xe-129 Dissolved in Atherosclerotic Plaques Zhaohui Han1, Nicholas N. Kuzma1 1University of Rochester, Rochester, USA

We report the first confirmed NMR signals from hyperpolarized Xenon-129 (HP Xe-129) dissolved in atherosclerotic plaques of mouse aortas. HP Xe-129 has a broad range of properties that make it a biosensor of choice to characterize biological systems. These properties include high sensitivity to molecular environments, high solubility in biological tissues, and several orders of magnitude increase in NMR signal intensity by optical pumping. Exploring the use of xenon for atherosclerosis diagnostics, we have performed ex-vivo NMR on excised mouse aortas. We have detected characteristic signals from HP Xe-129 dissolved in the atherosclerotic plaques of the apolipoprotein E-deficient mouse.

943. Free-Breathing Steady-State Free Precession 3D Coronary MRA: Comparison of Diaphragm and Cardiac Fat Navigator Gating Techniques Thanh D. Nguyen1, Pascal Spincemaille1, Matthew D. Cham1, Jonathan W. Weinsaft1, Martin R. Prince1, Yi Wang1 1Weill Medical College of Cornell University, New York, New York, USA

The objective of this study was to compare the performance of diaphragm navigator (DNAV) and cardiac fat navigator (FNAV) in free-breathing SSFP 3D CMRA. Imaging was performed in 16 volunteers at 1.5T using the PAWS real-time gating algorithm. Interpretable CMRA was obtained in all subjects with FNAV gating (0% failure rate) and only 14 subjects with DNAV gating (12% failure rate). Compared to DNAV gating, FNAV gating was found to provide more effective motion suppression, significantly better image quality (P<0.01), and a 30% improvement in average navigator efficiency (P=0.002).

944. A Comparison Study of Four Navigator Gating Techniques in Free-Breathing Steady-State Free Precession 3D Coronary MR Angiography Thanh D. Nguyen1, Pascal Spincemaille1, Matthew D. Cham1, Jonathan W. Weinsaft1, Martin R. Prince1, Yi Wang1 1Weill Medical College of Cornell University, New York, New York, USA

The objective of this work was to compare the performance of the restrospective (RETRO), accept/reject (A/R), diminishing variance algorithm (DVA), and phase ordering with automatic windows selection (PAWS) gating techniques in SSFP 3D coronary MRA. Experiments were performed in 10 volunteers without breath coaching and 15 vessels were imaged. PAWS provided significantly better image quality than A/R (P=0.02), DVA (P=0.01) and RETRO (P=0.002). PAWS and DVA were the most efficient algorithms, providing an approximately 20% and 41% higher navigator efficiency compared to A/R (P=0.01) and RETRO (P<0.001).

945. Navigator Echo Biofeedback (NEB) Significantly Increases Navigator Efficiency in Coronary MR Imaging Sebastian Feuerlein1, Martin Jeltsch2, Oliver Klass2, Hans-Juergen Brambs2, Martin HK Hoffmann2 1University of Ulm, Ulm, Germany; 2University of Ulm, Germany

The aim of our study was to investigate whether a modern respiratory biofeedback system using different diaphragm positions and supplemental oxygen could significantly increase navigator efficiency while maintaining image quality compared to conventional respiratory gated MRCA.According to our initial experiences such a Navigator Echo Biofeedback significantly increases navigator efficiency and thereby decreases total imaging time by about 40% compared to a conventional free breathing acquisition strategy.

Poster Sessions

182

Vessel Wall Imaging Hall D Monday 14:00-16:00

946. The Effect of Lipid Core Position on Carotid Fibrous Cap Stress Levels Samuel Alberg Kock1, Jens Vinge Nygaard, Anders K. Niemann1, Anette Klærke, William Paaske, Erling Falk, Won Yong Kim1 1Aarhus University Hospital Skejby, Aarhus N, Denmark

To determine if not only the size of atherosclerotic lipid cores, but also their position influence carotid fibrous cap stress levels, three computational models of a carotid bifurcation with varying lipid core placement were created using geometry based on MRI scans of a patient with a high-grade stenosis. Computational fluid structure interaction simulations were performed on the models revealing proximally based lipid cores to exhibit far greater stress levels than both distally and centrally located lipid cores. Computational analyses may yield valuable additional information concerning fibrous cap stress levels which may support current methods of diagnostics.

947. Ultra-Short TE Imaging Protocol for Detection of Aortic Calcification Daniel A. Herzka1, Reza Nezafat2, Juergen Rahmer3, Warren J. Manning2, Peter Boernert3 1Philips Research North America, Briarcliff Manor, New York, USA; 2Beth Israel Deaconess Harvard Medical School, Boston, Massachusetts, USA; 3Philips Research Europe, Hamburg, Germany

Ultra-short TE sequences are advantageous because they can capture signal from tissues with short T2, while preventing signal loss from sources of artifact such as off-resonance and susceptibility boundaries. We optimized a UTE protocol for visualization of calcified atherosclerotic lesions in vivo in human aortas. The protocol was tested on volunteers and a patient with known atherosclerosis. UTE yielded images with calcium deposits clearly co-localized with atherosclerotic lesions observed with black-blood FSE, and made possible detection of calcification on the luminal side of the aorta. These preliminary results indicate that calcium imaging with MR is feasible and worth further investigation.

948. Signal Features of the Atherosclerotic Plaque at 3.0T Versus 1.5T: Impact on Automatic Classification William Sean Kerwin1, Fei Liu1, Hunter Underhill1, Vasily Yarnykh1, Chun Yuan1 1University of Washington, Seattle, Washington, USA

We evaluated signal differences between 1.5T and 3T MRI of carotid atherosclerotic plaque using an automatic classifier. Despite being trained on only 1.5T data, subjects scanned at both field strengths yielded highly similar classification results for the presence and average areas of calcification, lipid-rich core, hemorrhage, and fibrous tissue. These results suggest that signal properties are sufficiently similar at 3T relative to 1.5T that classifier performance is not significantly affected.

949. Long Segment Dark Blood Carotid Artery Imaging with Pencil-Beam-Excitation and Diffusion Preparation at 3T Axel Bornstedt1, Peter Bernhardt1, Vinzenz Hombach1, Markus Kunze1, Jochen Spiess1, Nico Merkle1, Volker Rasche1 1Uniklinik Ulm, Ulm, Germany

Robust long segment (~150 mm) 3D dark blood vessel visualisation of the carotid arteries at 3T is accomplished with pencil beam excitation and diffusion prepared gradient echo imaging.

950. Magnetic Resonance Imaging Parameters of Atherosclerotic Plaque Burden Successfully Predict Manifested Cardiovascular Disease Venkatesh Mani1, Hamza El Aidi1, Mark Woodward1, Paul Muntner1, Silvia H. Aguiar1, Karen Beth Weinshelbaum1, Hiroaki Taniguchi1, John E. Postley2, Valentin Fuster1, Zahi A. Fayad1 1Mount Sinai School of Medicine, New York, New York, USA; 2Columbia University, New York, New York, USA

The purpose of this study was to evaluate if MRI plaque burden measures in conjunction with traditional risk factors improve predictive capacity for cardiovascular disease (mCVD) and may therefore be useful in pre identification of patients at risk for cardiovascular disease. MR measures of plaque burden were obtained from 296 patients and ROC curves were used to determine predictive capacity of MR derived parameters for predicting mCVD. Combining MR parameters with traditional risk factors provided highest retrospective predictive capacity for mCVD.

951. Longitudinal Observation of Carotid Artery Intraplaque Hemorrhagic Volume on Magnetic Resonance Direct Thrombus Imaging James Qiupeng Zhan1, Alan R. Moody2, General Leung2, Radhakrishnan Ravikumar2, Susan Crisp2 1Sunnybrook Health Sciences Centre, Toronto , Canada; 2Sunnybrook Health Sciences Centre, Toronto, Canada

A study was conducted to measure carotid artery intraplaque haemorrhage (IPH) volume over time using Magnetic Resonance Direct Thrombus Imaging (MRDTI) and correlate it with the occurrence of prior ipsilateral ischemic events. Patients who received multiple MRDTI scans and were diagnosed with complicated plaque were classified as either symptomatic (having previous events) or asymptomatic. Two trained observers analyzed the MRDTI data and determined IPH volumes. The intra-and inter-reader coefficients of variation were 6.2% and 8.2%, with correlation coefficients of 0.987 and 0.972. Relative mean change in IPH volume was 86.31±266.44% for asymptomatic patients and 10.23±54.87 % for symptomatic patients (P<0.01).

952. Improvements in Spatial Resolution Using a Novel 8-Element Carotid Phased Array Coil at 3T Niranjan Balu1, Vasily Yarnykh1, Cecil Hayes1, Joshua Scholnick1, Dongxiang Xu1, Baocheng Chu1, Chun Yuan1 1University of Washington, Seattle, USA

Carotid plaque imaging demands high SNR and high resolution. While current four-element phased array (PA) coils provide adequate SNR over a limited FOV, PA coils with additional elements can improve SNR and coverage. Using a novel eight-element PA (8PA) coil , upto 60% improvement in SNR and CNR were observed with a high-resolution (0.63mm in-plane) protocol. An ultra-high resolution (0.27mm in-plane) T1w black-blood quadruple inversion recovery sequence was implemented to assess the resolution improvement made possible by the 8PA coil. The 8PA coil enabled ultra-high resolution imaging with SNR improvements greater than 1.35 times with better vessel wall delineation.

Poster Sessions

183

953. Time Dependence of Necrotic Core and Fibrous Cap Quantitative Measurements with Gadobenate Dimeglumine Enhanced Carotid Plaque MRI at 3T Kevin DeMarco1, Xiaohai Ma1, John Brooks1, David Zhu1, Vasily Yarnykh2 1Michigan State University, East Lansing, Michigan, USA; 2University of Washington, Seattle, Washington, USA

Contrast-enhanced T1 weighted images (CE T1WI) demonstrate lipid rich necrotic core (LR-NC) with higher contrast-to-noise ratio (CNR) at 1.5T using gadodiamide. This study extends in vivo carotid plaque imaging to 3T and evaluates the effect of post-injection time on appearance of LR-NC using gadobenate dimeglumine by comparing CNR of LR-NC at 5 and 10 minutes after contrast injection in 43 outpatients with carotid stenosis. LR-NC CNR was similar at both time points, but with higher signal-to-noise ratio at 10 minutes. LR-NC volume measurement at both time points employing automated algorithm in MRI-PlaqueView is under investigation as is comparison with histology.

954. Magnetic Resonance Intraplaque Hemorrhage is Associated with Cerebrovascular Outcomes in Asymptomatic Male Patients with Non-Severe Stenosis Navneet Singh1, Alan R. Moody1, General Leung1, Ravikumar Radhakrishnan1, James Zhan1, Robert Magissano1 1Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Canada

Intraplaque hemorrhage (IPH) is an emerging marker of plaque instability. We investigated the correlation of MR detected IPH to cerebrovascular outcomes in a group of asymptomatic males with non-severe stenosis. A GE 1.5T MR and an 8 channel neurovascular coil array (USA Instruments, USA) using a 3D T1-weighted, fat-suppressed spoiled gradient echo sequence was used. The group with IPH (n=30) had six events (2 strokes, 1 amF, 3 TIAs) compared to no events in the MR IPH negative group (n=47) (RR = 9.60, 95%CI 1.21 to 75.9, p=0.0320).

955. Fibrous Cap Projection Length: A Better Biomarker of Plaque Vulnerability Than Lipid Core Size Dongxiang Xu1, Niranjan Balu1, Hunter R. Underhill1, Jianming Cai2, Chun Yuan1 1University of Washington, Seattle, Washington, USA; 2Chinese PLA General Hospital, Beijing, USA

Atherosclerotic disease has become one of the leading causes of death and major disability in the United States. In the past years, with the rapid development of using high resolution magnetic resonance imaging (MRI) technology in assessing atherosclerotic components, more and more evidences have shown that plaque composition is the decisive factor determining plaque vulnerability. Cai et al[1] using gadolinium-based contrast enhanced MRI showed that post contrast T1-weighted images can provide accurate quantitative measurements of the intact fibrous cap (FC) in advanced carotid atherosclerotic plaques in vivo. Based on this observation, an automatic FC detection method was developed and validated in our previous research [2]. In this study, we further explore lesion index Normalized Fibrous cap Projection Length Index (NFPLI). Our preliminary trial result has shown its more predictive power in plaque vulnerability than other plaque measurements.

956. Rapid 3D Vessel Wall Imaging at 3T: Optimization of Diffusion Preparation and Comparison to Other Protocols Mahender K. Makhijani1, Gerald S. Pohost2, Krishna S. Nayak1 1University of Southern California, Los Angeles, California , USA; 2University of Southern California, USA

Multi-contrast high-resolution imaging is used to characterize carotid plaque components. Standard multi-slice methods have long scan times and are not suited for plaque quantitation. Diffusion preparation has been recently proposed as a means for blood suppression in 3D vessel wall imaging. We characterize the tradeoffs of this approach when applied in conjunction with DIR and evaluate its performance at 3T in-vivo for bilateral carotid imaging and compare it with standard protocols and 3D SSFP approach. Cardiac gated 3D carotid vessel-wall datasets with 0.5x0.5x2.5 mm3 resolution over a 16x3.2x5cm3 FOV, and vessel wall CNR > 18, were obtained in 100 seconds

957. Detection of Plaque Vascularity Using Delayed Contrast Enhanced MRI: Correlation with Contrast Enhanced Ultrasound Radhakrishnan Ravikumar1, Alan R. Moody1, General Leung1, James Q. Zhang1, Peter N. Burns1, Susan Crisp1, Marilyn Robertson Horton1, Robert Maggisano1 1Sunnybrook Health Sciences Centre, Toronto, Canada

Plaque neovascularity, in addition to nurturing plaque growth can also be a causative factor for intraplaque hemorrhage thus predisposing the patient to increased risk of cerebrovascular events. Contrast enhanced ultrasound has been effectively used in identifying plaque neovascularity. The main purpose of this study was to see whether contrast enhanced MRI can help identify neovessels within the plaque and to compare the MR findings with contrast ultrasound findings. Delayed enhancement uptake patterns visualised on MR correlated well with neovascularity positive areas detected on contrast ultrasound.

958. High-Resolution T1- And T2-Weighted Black Blood Inner Volume 3D Fast Spin Echo Imaging for Characterizing Vessel Wall Components in Vivo Dimitris Mitsouras1, Robert V. Mulkern1, 2, Christopher D. Owens1, Tianxi Cai3, Amanda G. Whitmore1, Hale Ersoy1, Michael S. Conte1, Mark A. Creager1, Frank J. Rybicki1 1Harvard Medical School & Brigham And Women's Hospital, Boston, Massachusetts, USA; 2Children's Hospital, Boston, Massachusetts, USA; 3Harvard School of Public Health, Boston, Massachusetts, USA

Saphenous vein femoral-popliteal bypass graft imaging using a high spatial resolution (0.312mm in-plane) black-blood inner-volume 3DFSE sequence in 14 subjects revealed significantly larger wall area measured from T1W than T2W images (median ratio 1.52, median difference 5.45mm2, P<0.001). This significant difference was due to an increased outer wall boundary. T2 relaxometry of two specimens revealed shorter T2 values in an outer vs. an inner wall layer, accounting for the in vivo finding of differing areas measured from different contrast weightings. Correlative histology attributed the shorter T2 in the outer layer to collagen-rich fibrous tissue vs. myofibroblasts embedded in proteoglycan-rich matrix.

Poster Sessions

184

959. Gender Differences in Aortic Wall Thickness Regression by Magnetic Resonance Imaging (MRI) and Its Association to HDL Profile: The Plaque Follow Up Study by the National Institute of Aging (NIA) Gustavo Khattar Godoy1, Veronica R.S Fernandes1, Hossein Bahrami1, Christopher Sibley1, Ilan Gottlieb1, David A. Bluemke1, Joao A.C Lima1 1Johns Hopkins University, Baltimore, USA

The aim of the study was to assess the relationship between changes in aortic wall thickness measured by MRI with lipid profile and gender,of 114 participants of a randomized clinical trial using lipid-lowering drugs for 2 years.Were analized 3 segments of the thoracic aorta (ascending,arch and descending),using a double inversion recovery black blood fast spin-eco sequence with ECG-gating and T1-Weighted post-gadolinium.Were found a significant lower rate reduction of the aortic thickness in men when compared to women.Greater HDL levels were related to a decrease in ascending aortic wall thickness ,after adjustments for variables.

960. Quantitative Comparison of Carotid Plaque Composition Between 1.5 and 3.0T Field-Strengths Hunter R. Underhill1, Vasily L. Yarnykh1, Thomas S. Hatsukami1, Jinnan Wang1, Niranjan Balu1, Cecil Hayes1, Minako Oikawa1, Wei Yu1, Dongxiang Xu1, Baocheng Chu1, Bradley T. Wyman2, Nayak L. Polissar3, Chun Yuan1 1University of Washington, Seattle, USA; 2Pfizer, Groton, USA; 3The Mountain-Whisper-Light Statistical Consulting, Seattle, USA

We sought to assess the effects of field-strength on the quantification of carotid atherosclerotic disease. Participants with 16-79% carotid stenosis underwent high-resolution carotid MRI at both 1.5T and 3.0T. There was strong agreement between field-strengths in quantitative measurements of plaque morphology and detection of plaque components. However, the increased magnetic susceptibility of calcification and a stronger effect of paramagnetic ferric iron in hemorrhage at 3.0T may introduce a quantitative bias in measurements of these components. As such, 3.0T imaging may improve the detection of calcification, but more sensitive imaging techniques may need to be used for hemorrhage evaluation at 3.0T.

961. Improved Motion-Sensitized Driven Equilibrium (IMSDE) Blood-Suppression Sequence for Atherosclerosis Plaque Imaging at 3T Jinnan Wang1, 2, Vasily L. Yarnykh1, Baocheng Chu1, Chun Yuan1 1University of Washington, Seattle, Washington, USA

In this study, an improved version of motion sensitization driven equilibrium (iMSDE) sequence was proposed for carotid artery vessel wall imaging. By adding a new refocusing pulse, the iMSDE sequence is less sensitive to the B1 inhomogeneity at high field strength. Both phantom test and in vivo imaging has demonstrated that iMSDE sequence can dramatically increase signal level, when comparing with traditional MSDE sequence, without losing flow suppression efficiency.

962. High-Resolution Ultra-Short TE Imaging of Ex Vivo Human Carotid Plaques Correlates with CT Daniel A. Herzka1, Juergen Rahmer2, Reza Nezafat3, Ray Chan1, Wei Liu1, Peter Boernert2 1Philips Research North America, Briarcliff Manor, New York, USA; 2Philips Research Europe, Hamburg, Germany; 3Beth Israel Deaconess Harvard Medical School, Boston, Massachusetts, USA

Ultra-short TE (UTE) sequences have the advantage that they are able to capture signal components with very short T2. We investigate the use of single and multi-echo UTE sequences for the detection of calcium deposits in ex vivo human carotid samples with known atherosclerosis. UTE images correlated significantly with high-resolution CTs but with better soft-tissue contrast. Though low in intensity, the signal from calcifications is detectable with UTE MRI and may be complementary to current multicontrast atherosclerotic tissue characterization approaches. Further work is required to assess the feasibility of these acquisitions in vivo.

963. Passive Targeting of Atherosclerosis with Paramagnetic Lipid Nanoparticles in a Mouse Model of Vulnerable and Stable Plaques Glenda Sibylle van Bochove1, Leonie E M Paulis1, Dolf Segers2, Willem J M Mulder3, Rob Krams4, Gustav J. Strijkers1, Klaas Nicolay1 1Eindhoven University of Technology, Eindhoven, Netherlands; 2Erasmus Medical Center, Rotterdam, Netherlands; 3Mount Sinai School of Medicine, New York, New York, USA; 4Imperial College London, London, UK

Recently, a mouse model has become available where both stable and vulnerable atherosclerotic plaque phenotypes are induced by the placement of a tapered cast around the right carotid artery of apoE-/- mice. The aim was to evaluate the contrast generated in these plaques by injection of Gd3+ liposomes and Gd3+-micelles to obtain insight in plaque permeability. Both stable and vulnerable plaques appeared non-permeable for liposomes, while accumulation of micelles was observed in both lesion types. Therefore, liposomes are a good candidate for targeting endothelial markers and micelles may also be suitable for targeting factors inside the atherosclerotic plaque.

964. Molecular Imaging of Atherosclerosis Using PEG-Micelles Targeted by an ApoE Derived Peptide Eik Leupold1, Esad Vucic2, Willem Mulder2, Margitta Dathe1, Zahi Adel Fayad2 1Leibniz Institute of Molecular Pharmacology (FMP), Berlin, Germany; 2Mount Sinai School of Medicine, New York, USA

We use Gadolinium labeled PEG-micelles as contrast agents for MRI with ApoE knockout mice as atherosclerosis models. Targeting is achieved by an ApoE derived peptide (A2). The PEG-micelles consist of maleimide-PEG-DPPE, Gd-DTPA-BSA and rhodamine-DPPE. The micelles are produced by lipid-film hydration and A2 is coupled via maleimide/sulfhydryle conjugation.The micelles are 18nm in diameter and have a high stability. In vivo application (50mmol Gd/kg) results in a high, long lasting enhancement of atherosclerotic plaque in MRI using a 9.4T system. The maximum enhancement of 129±46% is reached at 24h, compared to 30±15% in mice treated with control PEG-micelles. Confocal microscopy was performed on sections taken from the thoracic aorta. A co-localization of A2 PEG micelles with macrophages in atherosclerotic plaques could be shown.A2 modified PEG-micelles containing Gd are a new contrast agent that is excellently suited for the MRI based diagnosis of atherosclerosis.

Poster Sessions

185

965. Comparison of Synthetic HDL Contrast Agents for Atherosclerosis Imaging David Peter Cormode1, Rohith Chandrasekar2, Karen C. Briley-Saebo1, Alessandra Barazza1, Willem J. Mulder1, Edward A. Fisher3, Zahi Adel Fayad1 1Mount Sinai School of Medicine, New York, USA; 2The Cooper Union for the Advancement in Science and Art, New York, USA; 3New York University, New York, USA

We have previously reported a macrophage specific MRI contrast agent based on HDL. To make this agent more versatile, we have formed Gd-labeled, synthetic HDL using a 37 or 18 amino acid peptide that mimics apoA-I, the main protein constituent of HDL. The effectiveness of these peptide-agents for detecting macrophages in the abdominal aorta of apoE knockout mice is assessed via MRI studies. Targeting to macrophages is confirmed by confocal microscopy. In addition, the biodistribution and pharmacokinetics are reported and the therapeutic properties of these particles in terms of removing cholesterol from macrophages are investigated.

966. Imaging Vasulcar Injury Using a Novel Gadolinium-Based Contrast Agent Pauliina Lehtolainen1, Manfred Junemann-ramirez, Panagiotis Kyrtatos1, Anthony N. Price1, Kenjiro Ikuta2, Yoshiki Katayama2, John F. Martin, Mark F. Lythgoe 1 Institute of Child Health and Department of Medicine, University College London, London, UK; 2Kyushu University,, Fukuoka, Japan

The vasculature is one of the most promising targets for a site -specific MRI strategy, as the diagnosis of vascular disease in its early stages is essential to a successful treatment intervention. Here we report on an endothelial-lesion specific contrast agent, evans-blue chelated gadolinium (EB-DTPA-Gd) for imaging the vascular damage and regeneration of vascular wall. Vascular injury generated by angioplasty was clearly distinguished by EB-DTPA-Gd accumulation by T1-weighted MR images using 9.4T scanner.

967. Comparison of Gadofluorine M and Gd-DTPA Relaxivities for Quantitation and Characterization of Atherosclerotic Plaque in Mouse at 11.7T Haiying Tang1, Richard Kennan1, Ching H. Chang1, Bernd Misselwitz2, Donna Suresch1, Dan Zhou1, Brett Connally1, Michael Klimas1, Donald S. Williams1, Richard Hargreaves1, Haiying Liu1 1Merck Research Laboratories, Rahway, New Jersey, USA; 2Bayer Schering Pharma AG, Berlin, Germany

Recent advances in MRI technology and novel imaging contrast agents have made MRI an important imaging modality for detecting and characterizing atherosclerosis. Gadofluorine M has been reported to target the extracellular matrix of plaque, and is an important marker of plaque staging. Comparisons of relaxivities and dose response in plaque are made between Gd-DTPA and Gadofluorine M at 11.7 Tesla. The results confirm that Gadofluorine M greatly helps in the identification and quantitation of plaque burden in major arteries of mouse model of atherosclerosis with improved sensitivity and efficiency, and may provide better characterization of plaque components at different stages.

968. Imaging of Macrophage Infiltration in an Abdominal Aortic Aneurysm Mouse Model Gregory Harrison Turner1, Alan R. Olzinski1, Roberta E. Bernard1, Karpagam Aravindhan1, Heather W. Karr1, Robert N. Willette1, Peter J. Gough1, Beat M. Jucker1 1GlaxoSmithKline, King of Prussia, Pennsylvania, USA

Abdominal aortic aneurysms result from a vascular inflammatory process involving macrophage recruitment. Abdominal aortic aneurysms (AAA) can be consistently produced in hyperlipidimic ApoE-/- mice by continuous infusion of Angiotensin-II (Ang-II). Administration of USPIO was used as an imaging biomarker for the distribution of macrophage within an aneurysm. These results demonstrate the feasibility of using a USPIO contrast agent as a surrogate for acute inflammatory processes in the aorta of ApoE-/- mice.

969. GdAAZTA-C17 (Q=2) Labeled High Density Lipoproteins (HDL) for the in Vivo Detection of Atherosclerotic Plaque Karen Briley-Saebo1, Simonetta Geninatti2, David Cormode1, Alessandra Barazza1, Wei Chen1, Edward Fisher3, Silvio Aime2, Zahi A. Fayad1 1Mount Sinai School of medicine, New York, USA; 2University of Torino, Torino, Italy; 3New York University, New York, USA

To increase CNR and reduce the dose administered, high relaxivity gadolinium chelates with two water exchange sites (q=2) were integrated into high-density lipoproteins (HDL). The q=2 HDL adduct was characterized relative to GdDTPA-DMPE (q=1) HDL, and the MR efficacy evaluated in mouse models of atherosclerosis. The results indicate that the q=2 lipid integrates into the lipid core. The q=1 lipid, however, formed a micelle that interacted with the surface. Similar MR arterial enhancement was observed after administration of 0.048 mmol Gd/Kg q=1 HDL and 0.018 mmol/Kg q=2 HDL. The q=2 HDL adduct may allow for low dose detection of atherosclerosis.

970. Characterization of an in Vivo Model of Atherosclerosis Using Histological and MRI Techniques Stephanie Elaine GarWai Chiu1, Alan R. Moody1, James Qiupeng Zhan1, Radhakrishnan Ravikumar1, General Leung1 1Sunnybrook Health Sciences Centre, Toronto, Canada

Intraplaque hemorrhage and plaque neovascularization are recognized as contributors to atherosclerotic plaque vulnerability, but current animal models do not consistently or spontaneously produce these types of lesions. As a first step towards building upon the commonly used hypercholesterolemic rabbit model, a low dose of recombinant human vascular endothelial growth factor (rhVEGF) was administered to a group of rabbits. These injections have been shown to increase both intramural endothelial cell and macrophage density in hypercholesterolemic rabbits. MRI using both an intravascular and an extravascular contrast agent was performed on the rabbits in an attempt to detect these changes non-invasively.

Poster Sessions

186

MRA: Continuous Table Movement Hall D Tuesday 13:30-15:30

971. Towards Automatic Patient Positioning and Scan Planning Using Continuously Moving Table Imaging Peter Koken1, Jochen Keupp1, Sebastian Peter Dries1, Daniel Bystrov1, Peter Börnert1 1Philips Research Europe, Hamburg, Germany

With the increasing number of MRI scan parameters, the operation of a clinical MRI system has become very complex. Improvements in the ease of use of are increasingly important. The idea of this feasibility study is to reduce the operator interaction needed to set up an examination to just selecting the anatomy to be studied by “pushing a single button”. While moving the patient into the MRI magnet, isotropic 3D continuously moving table (CMT) imaging is performed. In parallel, real-time image reconstruction and immediate organ identification is performed using fast image processing. Once the position and extent of the target organ is found, CMT scanning is terminated and the chosen anatomy is automatically positioned in the iso-center. The desired examinations can be started using the automatically derived geometry information without further operator’s interaction.

972. Continuous Table Movement for Peripheral MRA with Matrix Coils at 3.0T - Comparison to Standard Step-By-Step MRA Harald Kramer1, Karin A. Herrmann1, Peter Schmitt2, Michael Zenge2, Christian Glaser1, Maximilian F. Reiser1 1University Hospitals Munich - Grosshadern Campus, Munich, Germany; 2Siemens Medical Solutions, Germany

Because of the well known advantages of magnetic resonance angiography (MRA) like the excellent soft tissue contrast, the lack of ionizing radiation and the possibility of non invasive dynamic imaging, this imaging method established a serious alternative to DSA and CTA. One drawback is the complexity of the exam and the sometimes challenging procedure. One chance to overcome this limitation is the implementation of continuous table movement MRA which shortens and simplifies the entire exam.

973. Suppression of Image Artifacts Arising from Magnetic Field Inhomogeneity in Continuous Moving Table MRI Yo Taniguchi1, Shinji Kurokawa1, Suguru Yokosawa1, Hisaaki Ochi1, Yoshitaka Bito1 1Hitachi, Ltd., Kokubunji, Japan

Image artifacts and distortions arising from magnetic field inhomogeneity in continuous moving table (CMT) MR images have been investigated using computer simulation. A reconstruction algorithm using phase correction has also been developed from the simulation results, and it was stable in the presence of field inhomogeneity. From the images obtained in phantom experiments it was confirmed that artifacts in the experimental results were similar to those in the simulation results. Furthermore, the artifacts in the images acquired in experiments using both phantoms and volunteers were successfully suppressed by the phase correction technique.

974. Continuously Moving Table Peripheral CE-MRA (TimCT) on a 1.5 T Wide-Bore System in an Obese Population Florian M. Vogt1, Michael O. Zenge2, Stephan Kannengiesser2, Joerg Barkhausen1, Mark E. Ladd1, Harald H. Quick1 1University Hospital, Essen, Germany; 2Siemens Medical Solutions, Erlangen, Germany

State-of-the-art cylindrical wide-bore MRI scanners provide improved patient comfort for claustrophobic and obese patients. Recently, data acquisition and reconstruction during continuous table movement (TimCT) has been introduced which features 3D coronal slab MRA with centric reordering and increased spatial resolution at the distal end of the large field-of-view. In this study, 5 healthy volunteers and 10 obese patients with known PAOD underwent TimCT CE-MRA. Although examination of the patients on a conventional scanner was impossible because of patient size, moving-table peripheral CE-MRA was successful in all subjects on the wide-bore system. Furthermore, the workflow introduced with TimCT simplified scan planning.

975. Continuously Moving Table Acquisitions: Generalised Image Reconstruction Accounting for Field Effects (GIRAFFE) Rita Gouveia Nunes1, Joseph V. Hajnal1, Philip G. Batchelor2, David Atkinson3, David J. Larkman1 1Hammersmith Hospital, Imperial College London, London, UK; 2King's College London, London, UK; 3University College London, London, UK

Continuously moving table approaches allow more efficient acquisition of extended field-of-view images. Unfortunately, as the subject moves through the magnet bore, errors due to imperfections in the B0, gradient and RF fields accumulate leading to severe artefacts. Conventionally, to limit these artefacts, only linear sampling schemes are used and the thickness of the excitation slab reduced. We introduce a generalised method which allows for knowledge of such imperfections to be incorporated into the reconstruction leading to accurate images regardless of the chosen k-space sampling scheme. This flexibility is essential in order to simultaneously acquire multiple images with clinically relevant contrasts.

Cardiac Function Hall D Wednesday 13:30-15:30

976. Single Breath-Hold Cardiac Volumetry: A Faster New Approach by Sliding Slice Cine Imaging Peter D. Gatehouse1, Jennifer Keegan, Ricardo Wage, David N. Firmin 1Royal Brompton Hospital, London, UK

Aiming to avoid the need for stabilisation cycles, real-time cine bSSFP imaging was modified to slide the image slice continuously along the long axis of the heart. Cardiac function measurements and blood-myocardium contrast were compared against real-time as normally used with stabilisation on alternate cycles. The sliding-slice continuous cine enables more rapid volume acquisition at reduced blood-to-myocardium contrast.

Poster Sessions

187

977. Evaluation of Right Ventricular Function and Pulmonary Perfusion in Ross Procedure Patients Using Magnetic Resonance Imaging Anna Lakoma1, David Tuite1, John Sheehan1, Peter Weale, James Carr1 1Northwestern University, Chicago, Illinois, USA

The purpose of this retrospective study was to evaluate whether valve dynamics and pulmonary perfusion parameters as measured by MRI can predict right heart dysfunction in patients post Ross procedure.

978. TGRAPPA Accelerated Free Breathing Real-Time Cine Cardiac Imaging with a 32-Channel Coil Neil Isaac1, Sven Zuehlsdorff2, Peter Weale2, Sonia Nielles-Vallespin3, Renate Jerecic2, Harold Litt1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA; 2Siemens Medical Solutions, Chicago, Illinois, USA; 3Siemens Medical Solutions, Erlangen, Germany

A comparison of TGRAPPA accelerated real time cine images of the heart using a 32 channel phased array coil, in comparison with traditional segmented k-space acquisitions using a 32 channel coil, as well as traditional 8 channel phased array coil.

979. Increased Diastolic Pressure Gradients Are Measured During Dobutamine Stress Tests June Cheng Baron1, Ian Paterson1, Mark Haykowsky1, John Mackey1, Richard Thompson1 1University of Alberta, Edmonton, Canada

Measurement of blood pressure gradients (ÄP) between the atrium and ventricle during diastole provides insight into the ability of the ventricle to facilitate filling by rapid relaxation. We examine, for the first time, changes in ÄP during a dobutamine stress test to characterize stress-related increases in these gradients. In 8 subjects, heart rates increase from 58-77 (rest) to 106-160bpm at peak stress, with corresponding increases in filling pressure gradients from 2.4±0.5mmHg (rest) to 4.8±1.8mmHg at peak stress. We attribute increases in ÄP to increased diastolic suction and not pre-load, since end-diastolic volumes drop with stress by 35±16ml.

980. Volumetric Cardiac Quantification Using Three Dimensional Dual Phase Whole Heart MRI Sergio Andres Uribe1, Tarinee Tangcharoen1, Victoria Parish1, Ivo Wolf2, Reza Razavi1, Gerald Greil1, Tobias Schaeffter1 1Kings College London, London, UK; 2Deutsches Krebsforschungszentrum, Heidelberg, Germany

In this abstract we propose a new acquisition that allows precise cardiac volume quantification. The technique acquires isotropic data sets of the whole heart during systole and diastole in a single free breathing scan using independent navigators for each cardiac phase. Quantification of LV and RV cardiac volumes is performed using a semi-automatic segmentation tool. A comparison between the standard Simpson approach and the proposed method shows a good agreement for all volunteers and patients.

981. Inflow Quantification in 3D Cardiac MR: Implications for Whole Heart Coronary Imaging and 3D Cine Reza Nezafat1, Daniel A. Herzka2, Christian Stehning3, Dana C. Peters1, Anne Riley4, Kay Nehrke3, Warren J. Manning1 1Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA; 2Clinical Sites Research Program, Philips Research North America, Briarcliff Manor, New York, USA; 3Tomographic Imaging, Philips Research Europe, Hamburg, Germany; 4Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, USA

Large volume 3D cardiac MR imaging (CMR) is becoming more appealing with applications both in 3D cardiac cine and whole heart coronary imaging. The transition from single 2D slices or small 3D slabs to thicker 3D slabs theoretiecally could result in an increased SNR and better image registration. However, for CMR there is an associated penalty that results from saturation of blood flowing into the imaging volume which can affect blood SNR and blood-myocardium CNR. In this study, we investigated inflow enhancement (or lack thereof) in 3D single-phase imaging (for coronary applications) as well as cardiac cines (for function evaluation).

982. In-Vivo 3-D Left Ventricular Strain Estimation from a 3-D Tag Sequence Using Optical Flow Method Chun Xu1, Lawrence Dougherty2, Gamaliel Isaac2, Aaron Blom1, Joseph H. Gorman1, Robert C. Gorman1, James J. Pilla1 1University of Pennsylvania, Glennolden, Pennsylvania, USA; 2University of Pennsylvania, Philadelphia, Pennsylvania, USA

The aim of this work is to investigate the use of a 3-D MR tissue-tagging imaging sequence combined with a motion estimation approach using a 3-D Optical Flow Method (OFM) for the quantification of left ventricular (LV) mechanics. Utilizing imaging and OFM parameters optimized in a previous simulation study, this method was applied to a healthy volunteer, from which 3-D displacement fields were derived and used to quantify LV contractile functions. Regional heterogeneity of 3-D displacement and strain was characterized in high spatial resolution through out the human LV, with significantly shorter acquisition and analysis time compared with other methods

983. Association Between Elevated Fasting Glucose, in the Absence of Diabetes, and Increased Left Ventricular Mass in Women Michael L. Chuang1, Philimon Gona2, 3, Carol J. Salton1, Noriko Oyama1, Susan J. Blease2, Daniel Levy2, Christopher J. O'Donnell2, Warren J. Manning1 1Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA; 2the NHLBI's Framingham Heart Study, Framingham, Massachusetts, USA; 3Boston University, Boston, Massachusetts, USA

Elevated fasting glucose, in the absence of diabetes, is associated with increased left ventricular (LV) mass in adult women but not men. There were no differences in LV geometry or ejection fraction between subjects with normal or elevated fasting glucose for either women or men.

984. Automated Segmentation of the Left Ventricle Using Myocardial Effusion Threshold Reduction and Intravoxel Computation (METRIC) Noel Christopher Codella1, Jonathan W. Weinsaft1, Matthew D. Cham1, Matt Janik1, Martin Prince1, Yi Wang1 1Weill Medical College of Cornell University, New York, New York, USA

An automated left ventricular segmentation algorithm for cine balanced SSFP images that accounts for partial voxel effects through linear interpolation between the signals of blood and myocardium is presented.

Poster Sessions

188

985. Motion-Corrected Strain Calculation from Long-Axis MRI Strain-Encoded (SENC) Images Ahmed Amr Harouni1, Khaled Z. Abd-Elmoniem1, Monda L. Shehata1, David A. Bluemke1, Nael F. Osman1 1Johns Hopkins University, Baltimore, Maryland, USA

Strain measured from Strain-Encoded (SENC) images are currently extracted from fixed regions, which introduce large error especially in the LV freewall. In this work, we developed a novel algorithm to automatically detect and track the motion of heart wall in long-axis SENC images. We showed that strain values calculated from our algorithm are acceptable and close to strain values calculated from the manual segmentation.

986. Propagation of Complex Noise in a Displacement Encoding Experiment Non-Linearly Affects Quantification of Strain Daniel B. Ennis1, J Andrew Derbyshire2 1Stanford University, Stanford, California , USA; 2National Institutes of Health, Bethesda, Maryland, USA

We first define a simplified 4x4 matrix expression that describes the mathematics of an MRI displacement encoding experiment using homogenous coordinates. This expression is then used to characterize the effect of imaging noise on the strain calculated from simulated displacement measurements. It is shown that the error in estimating the strain is non-linearly related to both the image SNR and the imaging resolution. The highest strain errors occur for combined low SNR and high image resolution. Increases in imaging resolution (decreasing pixel size) can increase the error in the strain estimate even when SNR is held constant.

987. Tracking Motion in TMRI Data Using Binary Image Processing Techniques Tareq Alrefae1, Mohammed D. Alenezy2, Elena I. Popel2, Mehmet Bilgen3 1Kuwait University, Kuwait City, Kuwait; 2University of Kansas, Lawrence, Kansas, USA; 3Medical University of South Carolina, Charleston, South Carolina, USA

Tagged magnetic resonance imaging (tMRI) has found wide-spread applications in various clinical and research areas. The strength of this technique lies in its ability to reveal regional motion of tissue such as that observed in cardiac studies. For purposes of quantification, offline applied algorithms are developed to track the tissue motion of user-selected regions of interest (ROI). Examples of such algorithms include harmonic phase (HARP) techniques and others. To further enrich the library of tracking algorithms, we present an automated method that utilizes binary image processing techniques to follow the tissue motion of user-selected ROI in tMRI data.

988. A Model-Based Time-Reversal of Left Ventricular Motion Improves Cardiac Motion Analysis Using Tagged MRI Tareq Alrefae1, Mehmet Bilgen2 1Kuwait University, Kuwait, Kuwait; 2Medical University of South Carolina, Charleston, USA

Application of tMRI combined with sensitive motion estimation techniques, such as harmonic phase (HARP) analysis, has proven to be feasible and diagnostically valuable in evaluating the performance of normal or diseased hearts in live subjects using conventional global and regional measures. In the presence of large motions, however, the current analysis techniques including HARP fail to accurately describe the absolute displacement of the myocardial tissue. This paper addresses this issue and offers a solution - a simple time-dependent model and its time-reversal- providing motion estimates with improved performance even when the tissue is subject to large movements.

989. Improved Cardiac Strain Estimation from DENSE Using Automatic Outlier Rejection Sandeep Narendra Gupta1, Anthony Aletras2, Maureen N. Hood3, Vincent B. Ho3, Ehud J. Schmidt4, Pelin Aksit5 1GE Global Research, Niskayuna, New York, USA; 2NIH, Bethesda, Maryland, USA; 3NNMC and USUHS, Bethesda, Maryland, USA; 4GE Healthcare, Boston, Massachusetts, USA; 5GE Healthcare, Bethesda, Maryland, USA

DENSE technique allows quantification of regional myocardial strain. We present here a novel method for processing of DENSE data which automatically detects and rejects pixels with poorly conditioned strain calculation. With this outlier rejection method, a three-fold reduction in the variability of circumferential shortening and radial thickening quantification is demonstrated in human studies.

990. A Premature Ventricular Contraction Detection Method for Cardiac MR Acquisitions Using Morphology Feature Liewei Sha1 1GE Healthcare, waukesha, Wisconsin, USA

Premature Ventricular Contractions are ectopic heart beats with ventricular origin. The presence of PVCs degrades image quality, if the gated scans do not differentiate PVCs from normal beats. Accurate detection of PVC not only improves image, but also provides auxiliary information to facilitate diagnosis of ventricular arrhythmias. Many PVC detection algorithms have been proposed [1,2], few consider the noise in MR environment,including distortion due to magnetohydrodynamic effect, gradient noise, and radio-frequency interference. This work proposed a method to detect R-wave and PVC, using combined feature of MR noise resistant 2D VCG morphological distance, the R-peak duration and RR interval.

991. Relation of Myocardial Fiber Structure with Cardiac Wall Motion Using DTI and MR Tagging Yin Wu1, 2, Tracy Yee Chow1, 2, Ke Xia Cai1, 2, Ed X. Wu1, 2 1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong; 2Dept. of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong

LV structure is known to be associated with cardiac function, but the relation of myocardial fiber distribution with regional wall motion remains to be elucidated. In this study, both tagging and DTI were performed in adult rats. LV myocardium twist, circumferential strain, and myocardial fiber architecture were investigated. Results show that the myocardial fiber distribution has direct relation with the LV myocardium twist angle and magnitude of circumferential strain. Such integrated functional and structural analysis may provide more information for understanding the fundamental cardiac mechanics and assessment of pathological changes.

Poster Sessions

189

992. Model-Based Estimation of 3D Myocardial Motion Based on Cine DENSE MRI Patrick Helm1, Frederick Epstein1 1University of Virginia, Charlottesville, Virginia , USA

Multi-slice cine DENSE can acquire displacement-encoded images representing the 3D motion of the entire left ventricle with high spatial resolution and accuracy relative to conventional myocardial tagging, but still with finite signal-to-noise ratio and discrete spatiotemporal sampling. We developed a technique where a patient-specific cardiac model was employed to improve DENSE estimates of the continuous spatiotemporal displacement field throughout the 3D left ventricle. The model-based reconstruction of cardiac motion agreed closely with tagging when undersampled to similar spatial resolution. The higher spatial resolution of DENSE enabled the use of fewer model constraints and potentially improved estimation of 3D motion.

993. Epicardial Contour Extraction by LV-Metric and Active Contour Model Using Cardiac MRI Hae-Yeoun Lee1, Yi Wang1 1Cornell University, New York, USA

In this study, an automatic left ventricle (LV) segmentation algorithm using short-axis cine cardiac MRI is presented. To segment LV and detect endocardial contour, we compensate the coil sensitivity of magnitude images and apply region-growing scheme, termed LV-METRIC. To detect epicardial contour and segment myocardium (MC), we generate a circular map by polar mapping, extract and filter edge information using segmented LV. After defining the external force with prior knowledge, we apply guided active contour model to find epicardial contour, where initial contour is the endocardial contour from LV and only moves to radius direction on the circular map.

994. One Touch Imaging for Improved Cardiac Workflow Robert D. Darrow1, Vivek Vaidya2, Ambey Govenkar3, Rakesh Mullick2, Thomas K.F. Foo4 1GE Global Research, Niskayuna, USA; 2GE Global Research, Bangalore, India; 3Extenprise, Inc., Pune, India; 4GE Global Research, Niskayuna, USA

Cardiac examinations demand highly proficient technologists or operators to complete clinical studies in an efficacious and time-efficient manner. One Touch imaging minimizes operator impact on the quality of the cardiac examination and produces highly repeatable examinations. In addition, by reducing the number of steps needed to identify the cardiac scan planes to a single button push, a simplified cardiac exam is demonstrated with substantial timesavings. We demonstrate a seamlessly integrated image acquisition/feature recognition method that produces short-axis cardiac CINE images with a single button push in less than 10 minutes, including breath-holding time.

Myocardial Perfusion Hall D Thursday 13:30-15:30

995. Automated Breathing Motion Correction in First-Pass Myocardial Perfusion MRI Julien Milles1, Rob J. van der Geest1, Michael Jerosch Herold2, Johan HC Reiber1, Boudewijn PF Lelieveldt1 1Leiden University Medical Center, Leiden, Netherlands; 2Brigham & Women's Hospital, Boston, USA

In this work, we present a fully automatic algorithm for registration of perfusion data that is robust against the large contrast variations during bolus passage, and does not require manual interaction or ROI definition. Validation experiments on 45 MR perfusion studies demonstrate: 1)a high robustness, 2)a substantial reduction in LV center motion after registration, with an average motion of 0.64 ± 0.46 pixel, 3)an increase in the percentage of studies with a motion below 1 pixel from 32% before to 88% after registration and 4)a substantial improvement due to registration of the correlation and NMSE of perfusion curves compared to manually derived perfusion curves. We conclude that the ICA-based registration shows an excellent accuracy, robustness and computation speed, adequate for use in a clinical environment.

996. 3D HYPR-Based MRI Techniques for Myocardial Perfusion Imaging Orhan Unal1, 2, Julia Velikina1, Charles A. Mistretta1 1University of Wisconsin, Madison, Wisconsin, USA

In myocardial perfusion imaging, the goal is to differentiate contrast kinetics of normal and ischemic myocardium. The required high temporal resolution does not allow for acquisition of a fully sampled dataset in each time frame. As a result, reconstructed images suffer from loss of spatial resolution and/or low signal-to-noise ratio (SNR) and undersampling artifacts. Recently developed HighlY constrained backPRojection (HYPR)-based techniques in combination with a hybrid radial/Cartesian acquisition can provide relatively artifact free images with high SNR and high temporal resolution for large undersampling factors.

997. Arterial Spin Labeled Myocardium Perfusion Imaging with Background Suppression Zungho Zun1, Eric C. Wong2, Krishna S. Nayak1 1University of Southern California, Los Angeles, California , USA; 2University of California, San Diego, La Jolla, California , USA

We demonstrate myocardial perfusion imaging at 3 T using arterial spin labeling with background suppression. The measured perfusion rate follows a non-central chi distribution as verified by experiments. The number of averages that provides quantification of myocardial blood flow with a specific percentage confidence interval is roughly 200 times greater than that required for ASL cerebral blood flow measurement with the same confidence. ASL cardiac perfusion imaging is demonstrated in healthy volunteers with measured myocardial blood flow values matching literature values.

998. 3D First-Pass Myocardial Perfusion Imaging at 3T: Towards Complete Left Ventricular Coverage Taehoon Shin1, Houchun Harry Hu1, Samuel S. Valencerina2, Gerald M. Pohost1, Krishna S. Nayak1 1University of Southern California, Los Angeles, California , USA; 2Tenet Healthcare, Los Angeles, California , USA

Inadequate spatial coverage of the left ventricle in current 2D multi-slice first-pass myocardial perfusion imaging (MPI) limits the complete assessment of under-perfused volume. In this work, we investigate 3D MPI, an attractive alternative that provides contiguous volumetric coverage as well as greater signal-to-noise ratio efficiency. In healthy volunteers, we demonstrate 3D MPI with 2D parallel imaging at 3 Tesla. Complete coverage of the left ventricle in diastole with 3x4.5x10 mm3 spatial resolution is achieved. Excellent image quality was obtained, allowing semi-quantitative analysis and visualization of perfusion indices across the whole heart.

Poster Sessions

190

999. Towards Non Contrast Agent Myocardial Perfusion Imaging Using Spin-Echo Based Images with Blood Oxygenation Level Dependent Contrast at 3.0 T Uwe Heinrichs1, Tobias Frauenrath1, Jane Francis Utting1, Gabriele A. Krombach1, Rolf W. Günther1, Thoralf Niendorf1 1University of Aachen, University Hospital, Aachen, Germany

This study examines the feasibility of free breathing, black blood prepared, cardiac gated spin echo based imaging (UFLARE) at 3.0 T to generate BOLD contrast and T2*-maps of the myocardium, without geometric distortions. Phantom and volunteer studies demonstrate the geometrical integrity and high image quality obtained with UFLARE - even for strong T2*-weighting. Results show that T2*-weighted UFLARE may present a realistic alternative to contrast agent studies of myocardial perfusion, which avoids the drawbacks of EPI and gradient echo based imaging. Furthermore, the approach may be extended to map T2*, quantify myocardial iron content, and assess endothelial function.

1000. Quantitative Myocardial Perfusion Imaging Using Different TSENSE Accelerated Pulse Sequences Stefan Weber1, Andrea Kronfeld1, R. Peter Kunz1, Kerstin Münnemann1, Georg Horstick1, Karl Friedrich Kreitner1, Wolfgang G. Schreiber1 1Mainz University Medical School, Mainz, Germany

Quantitative first-pass myocardial perfusion imaging was performed using three TSENSE-accelerated (R=2) pulse se-quences (SR-TrueFISP, SR-TurboFLASH and SR-segEPI). Myocardial blood flow (MBF) was calculated using XSIM using the MMID4 model. All calculated MBF values were the in range expected for young healthy volunteers. However, SR-TurboFLASH and SR-segEPI yielded significant smaller MBF values than SR-TrueFISP. Furthermore, MMID4-fit quality was considerably lower using the SR-TurboFLASH or SR-segEPI pulse sequence compared to SR-TrueFISP. Therefore, under the shown experimental setting SR-TrueFISP seems to be the method of choice for quantitative myocar-dial perfusion imaging.

1001. Steady State Free Precession (SSFP) Cardiac 1st Pass Perfusion MRI: Left Ventricular Blood Pool Saturation Effects and Considerations at 1.5T Jens Vogel-Claussen1, Kakuya Kitagawa1, Joao A.C. Lima1, David A. Bluemke1 1Johns Hopkins Hospital, Baltimore, Maryland, USA

Traditionally gadolinium contrast is administered on a weight-based dosing scheme (mmol/kg). The purpose of this study was to evaluate the impact of this traditional weight-adjusted dosing scheme on the myocardial blood pool contrast concentration for quantitative analysis of first pass perfusion MRI. Traditional weight-adjusted dosing scheme for quantitative analysis of first pass SSFP perfusion MRI using 0.075mmol/kg does not result in uniform left ventricular blood pool contrast concentration. At doses >11ml gadopentetate dimeglumine the T2 effects appear to artificially decrease the measured LV contrast concentration, which cannot be fully corrected by the test bolus.

1002. Multi-Modal Cardiac MRI Monitoring of the Effect of Isoproterenol on Myocardial Perfusion, Function and Morphology Frank Kober1, Mark Cole2, Martine Desrois1, Carole Lan1, Patrick J. Cozzone1, Kieran Clarke2, Monique Bernard1 1CNRS UMR N 6612, Faculté de Médecine, Université de la Méditerranée, Marseille, France; 2University Laboratory of Physiology, Oxford, UK

Isoproterenol is a beta-adrenoreceptor agonist used in animal models to study the mechanisms of cardiac hypertrophy and failure. In this longitudinal CMR study, time-dependent changes in myocardial perfusion were assessed by arterial spin labeling along with morphologic and functional parameters using multimodal cardiac MRI during continuous administration of IP over 7 days. Multimodal MRI has shown that hypertrophy during IP administration is preceded by strong MBF increase and that cardiac function is maintained on a high level even at day 7. This indicates a mismatch between cardiac function and perfusion that might play a major role in the process of ventricular adaptation.

1003. Linear Arterial Input Functions for First-Pass Myocardium Blood Flow Assessment Using Calibration and Bloch Simulation Glenn Reynolds1, Micheal Jerosch-Herold2, Sandeep N. Gupta3 1GE Healthcare, Boston, Massachusetts, USA; 2Brigham and Women's Hospital, Boston, Massachusetts, USA; 3GE Global Research Center, Niskayuna, USA

Quantitative techniques, such as Fermi analysis, are used to assess ischemic regions of the myocardium and require Arterial Input Functions (AIF) and Myocardial Response Functions (MRF). First-pass perfusion imaging, using a single bolus of Gadolinium (Gd) contrast agent, results in a linear Myocardial Response Function and a less than linear Arterial Input Function. The purpose of this study is to demonstrate a method to generate a linear AIF using a combination of imaging, calibration, and Bloch simulation.

1004. Computational Fluid Dynamics Analysis of Bolus Dispersion in Myocardial Perfusion Measurements Dirk Graafen1, Kerstin Münnemann1, Stefan Weber1, Wolfgang G. Schreiber1 1Mainz University Medical School, Mainz, Germany

Using Computational Fluid Dynamics methodology dispersion of a contrast agent bolus was simulated in a straight vessel with different stenoses under steady state conditions. Two different perfusion conditions were examined: resting condition (inlet-velocity v = 0.1m/s) and stress condition (constant inlet-pressure p = 1010 Pa) both realizing a myocardial perfusion reserve of 5 in the absence of a stenosis. The dispersion in resting condition is greater than under stress conditions. Therefore, resting myocardial blood flow may be more underestimated in quantitative myocardial perfusion studies than stress perfusion.

1005. Detection of Coronary Artery Disease with Both Myocardial Blood Flow and Volume: Kyle Stephan McCommis1, Thomas A. Goldstein1, Robert J. Gropler1, Jie Zheng1 1Washington University School of Medicine, St. Louis, Missouri, USA

A newly developed quantitative MR perfusion technique was evaluated in normal and stenotic dogs, at rest and during Dipyridamole or Dobutamine-induced hyperemia. Myocardial perfusion maps were constructed to assess changes in both myocardial blood flow (MBF) and volume (MBV). Stenosis caused gradual attenuations of both hyperemic MBF and MBV in the stenosis subtended region. Interestingly, these parameters were also attenuated in the normal remote myocardial regions. These effects may imply coronary steal and auto-regulation, but further study is necessary. Measurements of both MBF and MBV may allow for more comprehensive diagnoses of coronary artery stenosis and better treatment planning.

Poster Sessions

191

1006. Inline Perfusion – a New Approach for Fully Automated Generation of Semi-Quantitative Parameter Maps Integrated Into Image Reconstruction Sven Zuehlsdorff1, Tongbai Meng2, Ying Sun3, Peter Kellman4, Jens Guehring5, Sonia Nielles-Vallespin6, Christine H. Lorenz2, Renate Jerecic1 1Siemens Medical Solutions USA, Inc., Chicago, USA; 2Siemens Corporate Research, Inc., Baltimore, USA; 3National University of Singapore, Singapore, Singapore; 4National Institutes of Health/NHLBI, Bethesda, USA; 5Siemens Corporate Research, Inc., Princeton, USA; 6Siemens AG Medical Solutions, Erlangen, Germany

The clinical use of first-pass MR myocardial perfusion imaging has shown a significant increase over the last years due to improved image quality and overall increased sequence performance in terms of spatial resolution and speed. Semi-quantitative or quantitative analysis of perfusion images usually requires significant user interaction and expertise that results in prohibitive long times to evaluate myocardial perfusion images. The goal of this work was to implement and test a framework for inline perfusion analysis which completely eliminates the need for user interaction and presents semi-quantitative parameter maps immediately after the scan together with the reconstructed images. The framework was tested on volunteers and patients. The feasibility of a fully automated perfusion analysis was demonstrated.

1007. Effects of Blood Fraction and Noise on a Model-Independent Deconvolution Method for Estimating Myocardial Blood Flow Nathan Allen Pack1, 2, Edward VR DiBella1 1University of Utah, Salt Lake City, USA

A model-independent deconvolution method, which uses iterative minimization and regularization to estimate the impulse response and myocardial blood flow from dynamic contrast-enhanced MRI perfusion images, was evaluated. Variations in the delay time between blood and tissue enhancement changed flow estimates up to 10%. The inclusion of a vascular blood signal was found to linearly increase estimates of blood flow using this deconvolution method. The use of model-independent analysis with noisy pixelwise dynamic MRI perfusion data resulted in flow estimates ~12% higher than flow estimates from large (200 pixel) regions.

Cardiac T2 & T2* Hall D Monday 14:00-16:00

1008. Improved Dark Blood Cardiac Morphology Imaging Using a Navigated ECG-Triggered BLADE Sequence: Scope of Applications Magalie Viallon1, Jean-Noël Hyacinthe1, Dominique Didier1, Pierre Croisille2 1Hopital Universitaire de Genève, GENEVA, Switzerland; 2Hopital Cardiologique Louis Pradel, LYON, France

T1 or T2 weighted TSE and T1 SE dark blood (DB) MR imaging (eventually combined with fat saturation (FS) or inversion recovery(IR)) are involved to characterize pathologies like DAVD, tumours, sarcoïdosis, myocarditis, to determine the area-at-risk in acute myocardium infarction (MI) or to detail cardiac morphology in congenital disease. But Dark-blood TSE methods are subject to artifacts (signal loss due to incoherent cardiac motion from RR length changes), resolution is restricted by the breathhold duration and remain low. In free breathing paediatric patients TSE DB techniques is dramatically hindered by the respiratory motion. PROPELLER then BLADE were new encoding strategies implemented to correct for intra and inter scan motion in brain morphological acquisition and offer a solution in uncooperative patients (Parkinson, stroke or Alzheimer diseases). We investigate here the capabilities of BLADE to circumvent motion sensitivity in DB cardiac morphology imaging and improve image quality.

1009. Detecting Right Ventricular Involvement in Reperfused Myocardial Infarction with T2-Weighted Cardiac MR and IR-Prepared SSFP with Delayed Contrast Enhancement Yuesong Yang1, Ram Vijayaraghavan1, Jay Detsky1, John J. Graham1, Warren Foltz1, Alexander Dick1, Graham A. Wright1 1Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Canada

Right ventricular (RV) myocardial infarction and dysfunction are independent indicators of poor prognosis in patients with acute myocardial infarction (AMI). Conventional DE-MRI has a limited role in the detection of the RV involvement in reperfused MI due to the thinned RV wall and pericardial fat tissue. We hypothesize that a T2-weighted cardiac MR technique with fat saturation is a better method to identify RV involvement in the acute stage of MI, and that the DE-MRI technique based on IR-prepared SSFP is a better technique to demonstrate RV involvement in the chronic stage of MI.

1010. Optimization of T2 and T2* Measurement in Myocardium at 3.0 T Jared Guthrie Cobb1, 2, Huairen Zeng2, 3, Cynthia Paschal2 1Vanderbilt University , Nashville, Tennessee, USA; 2Vanderbilt University, Nashville, Tennessee, USA; 3Vanderbilt University Medical Center, Nashville, Tennessee, USA

High field clinical scanners are increasingly available to researchers and clinicians and possess a significant SNR advantage over 1.5T scanners. New accelerated imaging techniques designed to optimize spatial and temporal acquisition may allow researchers to detect subtle changes in myocardial tissue, including changes that may be indicators of differences in oxygen utilization such as variations in T2 and T2*. In pursuit of this goal, we developed optimized breath hold scans to measure T2 and T2* in the myocardial septum at 3.0T.

1011. Single-Shot SSFP for Imaging of Edematous Myocardium in Patients Jordin D. Green1, 2, James Reavley Clarke2, Matthias G. Friedrich2 1Siemens Medical Solutions, Calgary, Canada; 2University of Calgary, Calgary, Canada

Cardiovascular MR can be used to visualize myocardial edema, a characteristic of patients with acute myocardial infarcts, but can be challenging in difficult patients. SSFP is T2/T1-weighted in the steady state with high imaging efficiency. The purpose of this study was to demonstrate the feasibility of using single-shot SSFP to image myocardial edema. The study was conducted in six patients. Results were compared to a conventional T2-weighted STIR sequence. Of the 32 myocardial segments positive for edema according to the STIR sequence, 24 were positive using SSFP. Of the 52 negative for edema according to STIR, 45 were negative using SSFP.

Poster Sessions

192

1012. Enhanced Detection of Myocardial Edema with Spectrally Selective Inversion Recovery-Prepared T2-Weighted Imaging Myra Sabene Cocker1, Oliver Strohm1, Jordin Daniel Green, 12, Steven M. Shea3, Hassan Abdel-Aty1, Matthias G. Friedrich1 1Libin Cardiovascular Institute at the University of Calgary, Calgary, Canada; 2Siemens Medical Solutions, Calgary, Canada; 3Siemens Corporate Research Inc., Baltimore, Maryland, USA

AASPIR (Asymmetric Adiabatic Spectral Inversion Recovery) was compared with STIR (Short T1 Inversion Recovery) for T2-weighted cardiovascular magnetic resonance (CMR) imaging of global and regional myocardial edema. Our findings support the implementation of AASPIR instead of STIR to visualize myocardial edema, as AASPIR allows for increased SNR and improved image quality.

1013. T2* Measurements in Myocardial Iron Overload: Comparison of Error Models on Optimized Analysis Protocol Marco Borri1 1University of Turin, Turin, Italy

Iron-induced heart failure is the main cause of death in transfusion-dependent anemia. In the presence of tissue iron, the shortening of the relaxation time constant T2* is used for detection of cardiac iron. It has been shown that patients with short T2* - corresponding with myocardial iron loading - have greater risk of systolic dysfunction. T2* measurements are performed with standardized protocols. An error estimation would help the clinical comparison of T2* measurements, especially in single patient’s follow-up. In this work an optimized analysis protocol is indicated and five different error models are compared.

1014. Comparing Myocardial T2* and T2 Measurements in Thalassemia Patients Taigang He1, Peter D. Gatehouse1, Gillian C. Smith1, Raad H. Mohiaddin1, Dudley J. Pennell1, David N. Firmin1 1Royal Brompton Hospital and Imperial College London, London, UK

The aim of this study is to compare myocardial T2* and T2 measurements in vivo in order to establish the relationship between them. In total 137 thalassemia patients were scanned on a 1.5T MRI scanner. It indicates that T2* of 20ms is a useful indicator to identify patient with cardiac iron. It also demonstrates that mmyocardial T2* measurement correlated linearly with T2 measurement in TM patients with iron overload. These findings suggests that both T2* and T2 measurements can be used for assessment of iron overload in the heart for transfusion dependent diseases such as thalassemia.

1015. Multi-Spiral MRI for Cardiac T2-Star Determination Philipp Ehses1, Nicole Seiberlich1, Peter Nordbeck1, Florian Fidler2, Peter Michael Jakob1, 2, Wolfgang Rudolf Bauer1 1University of Würzburg, Würzburg, Germany; 2Research Center Magnetic-Resonance-Bavaria, Würzburg, Germany

Cardiovascular T2* magnetic resonance imaging is a valuable tool in the diagnosis of heart disease. In this work, a multi-spiral method for cardiac T2* determination is presented. A multi-spiral sequence is one that acquires each spiral arm multiple times after an excitation in order to generate multiple T2* contrasts. The spiral trajectory was chosen because it inherently refocuses motion- and flow-induced phase errors, which can be beneficial for cardiac applications.

1016. Postmortem Insitu MRI as an Adjunct to Autopsy for the Diagnosis of Myocardial Infarction Christian Jackowski1, 2, Marcel Warntjes1, 3, Anders Persson1, Michael Thali2, Johan Berge4 1University of Linköping, Linköping, Sweden; 2University of Bern, Bern, Switzerland; 3Division of Clinical Physiology, University of Linköping, Linköping, Sweden; 4Department of Forensic Medicine, Linköping, Sweden

Autopsy diagnosis of myocardial infarction (MI) is still challenging because many lethal ischemic events do not lead to visible myocardial alterations. In these cases the lack of survival time prohibits myocardial reactions after ischemia, such as edema and inflammatory responses. Postmortem non-contrast enhanced insitu MRI (pm-MRI) may support the diagnosis of peracute MI. Being extremely sensitive to water distribution alterations within the myocardial tissue pm-MRI can accurately visualize areas of decreased micro-circulation. The extent of the ischemia is shown by a lowered signal in T2-weighted and proton density weighted images that have been optimized for the post-mortem conditions. As pm-MRI also reliably demonstrates acute, subacute and chronic infarction it might even serve as an alternative in cases in which traditional autopsy is refused for different reasons.

1017. Diffusion-Weighted Imaging Improves the Quantification of Myocardial Oxygenation When Arrhythmias Are Present Kyle Stephan McCommis1, Ioannis Koktzoglou2, Haosen Zhang1, Debiao Li2, Robert J. Gropler1, Jie Zheng1 1Washington University School of Medicine, St. Louis, Missouri, USA; 2Northwestern University, Chicago, Illinois, USA

Double-inversion-recovery (DIR) and diffusion-weighted (DW) prepared T2 images were obtained to determine the myocardial oxygen extraction fraction (OEF) in stenotic canines. These T2 and hyperemic OEF values were determined in the left-anterior descending (LAD) stenosis-subtended region and the remote normal left-circumflex (LCX) region. No significant T2 or OEF differences were found between the two methods. However, the DW technique shows better image quality and OEF accuracy when irregular EKG-triggering or arrhythmias occurs.

1018. Myocardial Iron Distribution in Thalassemia: An in Vivo Study with Black Blood T2* Imaging Taigang He1, Peter D. Gatehouse1, Dudley J. Pennell1, David N. Firmin1 1Royal Brompton Hospital and Imperial College London, London, UK

A black blood T2* technique was employed to investigate myocardial iron distribution in 55 thalassemia patients. The study was conducted on a 1.5T MRI scanner. Images were obtained in the mid-ventricular with 8 echo times and compared for each patient. This is the first in vivo study to demonstrate that myocardial iron deposition is uneven and dominantly in the epimyocardial region in iron overloaded thalassemia patients. This finding agrees well with previously published autopsy reports. These data suggest that T2* measurements in-vivo should use large transmural regions of interest.

Poster Sessions

193

1019. Longitudinal Analysis of Heart and Liver Iron in Thalassemia Major Leila Noetzli1, Nilesh Ghugre1, Thomas Coates1, John Wood1 1Childrens Hospital Los Angeles, Los Angeles, California , USA

The relationship between heart and liver iron in patients with thalassemia major has been complex and ambiguous. There has been evidence of high liver iron being associated with high heart iron, but there seems to be no correlation between the two at any given time. To address this issue, we retrospectively analyzed patients who had three or more MRIs to estimate their liver and heart iron. Through this longitudinal analysis, we found that the majority of patient’s hepatic iron concentration (HIC) versus cardiac R2* trajectories follow a counterclockwise hysteresis loop. In particular, heart iron lags with respect to liver iron. This finding is helpful to understand the complex relationship between heart and liver iron movement.

Animal Cardiac Imaging Hall D Tuesday 13:30-15:30

1020. Monitoring Dynamic Calcium Homeostasis Alterations by Cardiac Manganese-Enhanced MRI (MEMRI) with T1 Mapping in a Murine Myocardial Infarction Model Ben Waghorn1, 2, Tiffany Edwards2, Yuhui Yang2, Nathan Yanasak2, Tom Hu2 1Georgia Institute of Technology, Augusta, Georgia, USA; 2Medical College of Georgia, Augusta, Georgia, USA

There is a critical need for non-invasive monitoring of calcium homeostasis in viable myocardial tissue adjacent to necrotic myocardium after myocardial infarction. This study demonstrates that T1 mapping of murine cardiac Manganese-Enhanced MRI can be used to quantify the in-vivo manganese content. Furthermore, the application of this T1 mapping protocol to a myocardial infarction model demonstrates the sensitivity of the technique to delineate regions of the heart with abnormal Mn uptake. This information can potentially be used to estimate salvageable myocardium in a pre-clinical myocardial infarction mouse model.

1021. Optimization of 3-D Tag Sequence and OFM Using a Synthetic Tag Model Chun Xu1, James J. Pilla1, Gamaliel Isaac2, Aaron Blom1, Joseph H. Gorman1, Robert C. Gorman1, Lawrence Dougherty2 1University of Pennsylvania, Glennolden, Pennsylvania, USA; 2University of Pennsylvania, Philadelphia, Pennsylvania, USA

The aim of this study is to present a novel method of estimating high-resolution 3-D myocardial motion using 3-D tags combined with optical flow method (OFM utilizing a simulation model. A synthetic 3-D tagged cardiac volume was constructed, and deformed by a known systolic flow fields. Prior to phase-to phase pixel displacement estimation, cross correlation coefficient (CC) between the known and estimated flow fields was maximized by adjusting the tag and OFM parameters. This study demonstrates that optimized 3-D OFM combined with 3-D tag sequence has the potential to generate in-vivo myocardial displacement rapidly and accurately.

1022. Noninvasive Visualization of Myocardial Inflammation Using Magnetofluorescent Nanoparticle-Contrasted MRI in Rat Autoimmune Myocarditis Cheongsoo Park1, Eun Jeong Ahn2, Hyo Eun Park1, Kyuhong Lee1, Tae-Jong Yoon3, Ki-Bae Seung2, Chaejoon Cheong1, Ki Yuk Chang2, Kwan Soo Hong1 1Korea Basic Science Institute, Cheongwon, Republic of Korea; 2the Catholic University, Seoul, Republic of Korea; 3Massachusetts General Hospital, Boston, Massachusetts, USA

Myocarditis is defined as inflammation of the myocardium, mostly caused by viral infection, which leads to autoimmune activation against the host¡¯s own myocardial tissue. Endomyocardial biopsy is still considered to be the gold standard for diagnosing Myocarditis, however it is invasive and low sensitive because of sampling error and high inter-observer variability. Therefore, a novel diagnostic modality to detect the inflammation of myocardium through noninvasive means is needed. Here we investigated whether nanoparticle-contrasted cardiac MRI would be feasible and effective in detecting the status, and discriminating the grade of inflammation in a rat model of experimental autoimmune myocarditis (EAM).

1023. Cardiac MRI @ 7 Tesla: Initial Experiments in Pigs Harald H. Quick1, 2, Kai Nassenstein2, Frank Breuckmann2, Stefan Maderwald1, 2, Lena Schäfer2, Mark E. Ladd1, 2, Jörg Barkhausen2 1Erwin L. Hahn Institute for MRI, Essen, Germany; 2University Hospital Essen, Essen, Germany

Cardiac MRI at high field strengths potentially benefits from the increased signal-to-noise ratio (SNR) inherent to high-field MRI. In order to exploit the full SNR potential for cardiac MRI, a number of artifacts and imaging constraints related to the high field strength have to be overcome. The purpose of this study was to perform cardiac MRI in a pig model on a whole-body 7-Tesla MR scanner to evaluate potential advantages and disadvantages specifically associated with cardiac MR imaging at this high field strength.

1024. Cardiac Function in Post-Cardiac Arrest Mice by MRI and Effect of Nitrite Treatment Stasia Ann Anderson1, Cameron Dezfulian1, Aleksey Alekseyenko1, Mark T. Gladwin1 1National Institutes of Health, Bethesda, Maryland, USA

We examined a mouse model of cardiac arrest by cardiovascular MRI and describe the features of post-arrest cardiac function and the effect of nitrite treatment. We hypothesized that systemic NO2 is depleted during global ischemia (cardiac arrest) and its early repletion could protect the heart from reperfusion injury. Cardiovascular MRI demonstrated the existence and extent of RV dysfunction in a mouse model of cardiac arrest. Systemic nitrite after global ischemia is associated with improved pulmonary blood flow, cardiac function, survival and neurological function in survivors. MRI outcomes indicate RV ejection fraction and contractility are improved by nitrite treatment.

Poster Sessions

194

1025. ECG-Gated Cardiac MRI in Mice on a Clinical 3.0T MR Scanner Jie Huang1, Xiaohai Ma1, 2, Beihua Zhong1, Donna Wang1, Mark DeLano1 1Michigan State University, East Lansing, Michigan, USA; 2Beijing Anzhen Hospital, Beijing, People's Republic of China

Transgenic manipulations in mice are increasingly used to probe genetic and physiological aspects of human cardiovascular physiology. Cardiac MRI in humans is recognized as a robust and accurate method for in vivo assessment of cardiac morphology and function. However, due to the small size and fast rate, cardiac MRI in mice is usually performed on high-field animal scanners significantly limiting the opportunity for cardiac MRI research in mice. In this study we demonstrate the feasibility of performing cardiac MRI in mice with a clinical 3.0T system without the need for an amplifier to detect the R-wave for ECG-gating.

1026. Cardiovascular Phenotyping of the Mouse Heart Using 4-Dimensional Radial Acquisition and Liposomal Gd-DTPA Elizabeth Kathleen Bucholz1, Ketan Ghaghada1, Yi Qi1, Srinivasan Mukundan1, G. Allan Johnson1 1Duke University, Durham, North Carolina, USA

We propose a method for high-throughput cardiovascular phenotyping of the mouse using a 4D radial MRI pulse sequence in conjunction with liposomal Gd-DTPA. To validate the usefulness of the technique, myocardial function was evaluated in a population of 12 mice: 4 C57BL/6J, 4 DBA/2J, and 4 DBA/2J CSQ+. Images were acquired at a resolution of 87x87x348 µm3, with a temporal resolution of 9.6 ms, and 10-12 phases of the heart cycle were captured with a total acquisition time of 16 minutes. Calculation of ejection fraction (EF), end diastolic volume (EDV), and end systolic volume (ESV) were determined to be statistically different for all three populations of mice.

1027. Functional Effects of Human Embryonic Stem Cell-Derived Cardiomyocyte Transplantation on Chronic Myocardial Infarction in Rats Anna Naumova1, Sarah Fernandes1, 2, Vasily Yarnykh1, Veronica Muskheli1, 2, Chun Yuan1, Charles E. Murry1, 2 1University of Washington, Seattle, Washington, USA; 2Center for Cardiovascular Biology, Institute for Stem Cell and Regenerative Medicine, Seattle, Washington, USA

Cell transplantation using derivatives of embryonic stem cells (ESCs) is a promising therapeutic approach for heart failure. In real clinical practice, the patients with severe heart failure are most in need of cell transplantation therapy. This is the first study to explore restoration effects of hESC-cardiomyocyte transplantation on chronic myocardial infarction. We found that rat cardiac function was moderately improved in one month after cell transplantation into mature infarction. We assume that effect of human cardiomyocyte transplantation to chronic myocardial infarction will become more apparent during a long-term observation, when graft size would reach its functional capability.

1028. An Optical Fiber-Based Gating Device for Cardiac and Abdominal MRI of Small Animals Adrian Rengle1, Loredana Baboi1, Hervé Saint-Jalmes2, 3, Raphaël Sablong1, Olivier Beuf1 1INSA-Lyon, Université Lyon 1, Villeurbanne, France; 2Faculté de Médecine, Université Rennes 1, Rennes, France; 3Centre Eugène Marquis, Rennes, France

An optical-based device designed to synchronize MRI acquisition on small animals was developed using a transmit-receive pair of optical fibers. Light from a laser diode was focused into the transmit fiber and impinged upon the moving skin. The reflected light was detected by the receive fiber and then carried to a light-voltage amplified photodiode. The output signal was interconnected with a commercial trigger unit. The optical-based signals recorded on mice were correlated with both respiratory and heart motions. Signal amplitudes were large enough to perform an easy adjustment of gating level with good differentiation between cardiac and respiratory signal. The signal was totally unaffected by radiofrequency pulses or currents induced by the magnetic field gradients switching used for imaging. This optical-based gating device was used successfully for dual cardiac and respiratory synchronization for heart and liver examinations of mice at 4.7T. The device developed using thin optical fibers is simple to use and well suitable for small animal MRI using high field strength narrow bore systems.

1029. Cine-MRI vs. 2D-Echocardiography to Measure Left Ventricular Function in Rat Heart in Vivo Daniel J. Stuckey1, Carolyn A. Carr1, Damian J. Tyler1, Kieran Clarke1 1University of Oxford, Oxford, UK

Two dimensional echocardiography is the most commonly used method for studying cardiac morphology and function in small animals. We have compared 2D-echo with cine-MRI measurements of function in control and infarcted rat hearts and demonstrated strong correlations between the two modalities. However, cine-MRI had greater reproducibility and left ventricular ejection fractions were 12 „b 6% higher when measured using MRI. The accuracy of cine-MRI allows the identification of alterations in heart function that may be missed if using 2D-echo. Therefore, caution should be taken when comparing functional results acquired using short axis 2D-echo vs. cine-MRI.

1030. Magnetic Resonance Elastography Based Method for Quantitating Shear Stiffness Within a Heart Simulating Phantom Using a Thin Spherical Shell Model Arunark Kolipaka1, Kiaran P. McGee1, Anthony J. Romano2, Kevin J. Glaser1, Philip A. Araoz1, Armando Manduca1, Richard L. Ehman1 1Mayo Clinic, Rochester, USA; 2Naval Research Laboratory, Washington, District Of Columbia, USA

Knowledge of the mechanical properties of the myocardium has the potential to provide clinically relevant data for diagnosing a variety of cardiac disease processes. MR elastography (MRE) is a phase-contrast MR-based method for spatially resolving shear stiffness. We propose a new MRE-based model for estimating shear stiffness in a spherical shell geometry using a model of shear wave propagation within a thin spherical shell. This study describes the analysis of MRE-derived estimates of shear modulus using this model in varying thickness shells. This model may find useful applications in the heart, eye and bladder.

Poster Sessions

195

1031. Validation of MR Elastography Derived Stiffness Maps Using Established Pressure-Volume Model in a Simulated Heart Model Arunark Kolipaka1, Kiaran P. McGee1, Philip A. Araoz1, Richard L. Ehman1 1Mayo Clinic, Rochester, USA

It is appreciated that change to the mechanical properties of the myocardium are associated with a variety of cardiac disease processes. MR elastography (MRE) is a phase-contrast based MR technique capable of quantitating shear stiffness under static imaging conditions. This study describes the use of MRE to measure shear stiffness in a phantom undergoing dynamic volumetric changes. MRE derived measures of shear stiffness are compared to those derived from a pressure-volume derived method for calculating shear modulus of the left ventricle.

Contrast Agents for MRA Hall D Wednesday 13:30-15:30

1032. Gadobenate Dimeglumine for Contrast-Enhanced MR Angiography of the Carotid, Renal, and Peripheral Arteries: Overview of Phase III Clinical Trials Gilles Soulez1, Siegfried Thurnher2, Nicoletta Anzalone3, Gianpaolo Pirovano4 1University of Montreal, Montreal, Canada; 2University of Vienna, Vienna, Austria; 3San Raffaele Hospital, Milan, Italy; 4Bracco Diagnostics Inc., Princeton, New Jersey, USA

Results of clinical trial evaluating Gd-BOPTA for CE-MRA are presented. In the carotid arteries, blinded readers noted significantly (p<0.001) increased specificity and accuracy compared to 2D-TOF MRA. The sensitivity, specificity, and accuracy of CE-MRA for renal artery stenoses ranged between 60–84%, 89–95%, and 80–87%, respectively. For peripheral MRA, the sensitivity (54–81%), specificity (90%–95%), and accuracy (85%–88%) of CE-MRA for detection of significant iliofemoral disease was significantly (p<0.001) better than TOF MRA (33–63%, 74–89% and 68–77%, respectively). Gd-BOPTA was safe and accurate for CE-MRI at a dose of 0.1 mmol/kg.

1033. Low Dose, Contrast-Enhanced MR Angiography of the Lower Extremities at 3.0 Tesla Reza Habibi1, Derek G. Lohan1, Mayil S. Krishnam1, Fatemeh Barkhordarian1, Mehdi Jalili1, Roya Saleh1, Stefan G. Ruehm1, John Paul Finn1 1UCLA, Los Angeles, USA

Even though the exact correlation between the gadolinium dosage and occurrence of nephrogenic systemic fibrosis (NSF) in patients with low GFR remains to be established, it seems reasonable to minimize dose in susceptible patient groups, awaiting further clarification. The purpose of this study was to assess the feasibility of low-dose CE-MRA of the lower extremities at 3.0 Tesla and to compare the image quality with high-dose and intermediate-dose protocols. The results of our study showed that, taking advantage of the higher SNR at 3.0T, contrast dose for lower extremity MRA can be reduced several fold without any compromise in image quality.

1034. Targeted Contrast Enhancement Using Linear System Theory Daniel Kopeinigg1, 2, Dominik Fleischmann1, Matus Straka1, Rudolf Stollberger2, Roland Bammer1 1Stanford University, Stanford, California , USA; 2Medical University Graz, Graz, Austria

Correct timing of the contrast bolus arrival is a crucial part in CE-MRA. The inability to play continuous waveforms in clinically used power injectors is also an issue in achieving a constant vessel target enhancement. FORWARD was developed to account for this limitation, as well as of physiological limitations like maximum injections flows, among others. In the FORWARD process, characteristics of the test bolus are used to tailor the injection profile to create a more constant vessel enhancement. The possibility to analyze the contrast agent bolus over time and the corresponding dispersion leads to new optimization methods for k-space sampling.

1035. Three-Dimensional High Spatial Resolution Magnetic Resonance Angiography of the Supra-Aortic Arteries at 3.0 Tesla: A Contrast Dose Reduction Study Anderanik Tomasian1, Noriko Salamon, Derek Lohan, Mayil Krishnam, J. Pablo Villablanca, J. Paul Finn 1UCLA, Los Angeles, USA

The purpose of our study was to prospectively establish the non-inferiority of diminished dose regimens compared to higher dose regimens as reflected in the diagnostic image quality of high-spatial-resolution three-dimensional MR angiography of the supra-aortic arteries at 3.0 Tesla.High spatial resolution CE-MRA of the supra-aortic arteries at 3.0T can be performed with a gadolinium dose at least as low as 0.05 mmol/kg, without compromising image quality compared to 0.1 mmol/kg and 0.15 mmol/kg. Although further work is warranted, these initial results suggest that adoption of low-dose protocols in clinical practice may diminish sensitivity to contrast dose-dependent complications and result in cost savings.

Myocardial Viability Methods & Applications Hall D Thursday 13:30-15:30

1036. Improved Dark Blood Delayed Enhancement Imaging with Triple IR Preparation Wolfgang G. Rehwald1, Michael Salerno, Enn-Ling Chen, Robert M. Judd, Raymond J. Kim 1Siemens Medical Solutions, Chapel Hill, North Carolina, USA

We developed a dark blood delayed enhancement technique for MR imaging of myocardial viability employing a triple IR preparation. We implemented the method on a 1.5T clinical MRI scanner and evaluated it in dogs. The contrast between infarct and blood pool improved dramatically compared to the clinical gold standard (GS) while still providing adequate infarct SNR. Compared to previous double-preparation dark blood techniques timing was more flexible and SNR was improved. The slice-selective inversions and readout could be played when the heart was in a similar position providing a homogeneous preparation and reliable blood signal suppression.

Poster Sessions

196

1037. Cardiac MRI: How Much Myocardial Damage is Necessary to Detect Focal Late Gadolinium Enhancement? Kai Nassenstein1, Frank Breuckmann2, Christina Bucher1, Gernot Kaiser2, Thomas Konorza2, Gerd Heusch3, Joerg Barkhausen1 1University Hospital Essen, Essen, Germany; 2Universitiy Hospital Essen, Germany; 3University Hospital Essen, Germany

Detection of structural myocardial abnormalities in non-ischemic diseases is difficult by cardiac MRI, because non-ischemic diseases typically cause multifocal myocardial damages and affect only a small amount of myocardium. To estimate how much myocardial damage is necessary to detect focal myocardial lesions by late enhancement, experimental coronary microembolization was performed in 18 pig as a model for a multifocal myocardial pathology. Our results show, that focal myocardial lesions exceeding 5% of myocardium per section could be detected in vivo by late gadolinium enhancement in 86%.

1038. Late Gadolinium Enhancement Imaging with Automatic Establishment of the Optimal Inversion Delay J.B.M. Warntjes1, 2, J. Kihlberg1, J. Engvall1 1Center for Medical Imaging Science and Visualization (CMIV), Linköping, Sweden; 2Division of Clinical Physiology, Linköping, Sweden

To establish the optimal inversion delay time for inversion recovery images in a Late Gadolinium Enhancement examination is challenging. The optimal delay time depends on many factors such as patient weight, contrast dose and time after contrast injection. A method is presented that allows to visualize LGE images with an inversion delay time that is free to choose. All these images are based on a single breath-hold scan. The procedure is implemented into the PACS visualization software and helps to interactively find the optimal inversion delay for all subsequent MR scans.

1039. Automatic Detection and Quantification of Non-Viable Myocardium in Late Enhancement Images Anja Hennemuth1, Achim Seeger2, Ola Friman1, Stephan Miller2, Heinz-Otto Peitgen1 1MeVis Research, Bremen, Germany; 2University Hospital Tübingen, Tübingen, Germany

Late enhancement imaging is proven to be suitable for the assessment of myocardial infarctions. The purpose of our work was the development and evaluation of an automatic and thus reproducible method to detect and quantify non-viable tissue in short axis late enhancement images. The developed methods are based on an intensity distribution model combined with a watershed segmentation. For evaluation 15 datasets were segmented by experts, with the common 3σ−method and with the new automatic algorithms. Segment-based volume analysis correlated well for automatic and manual segmentations but not for 3σ−results. Overlap comparisons also indicate the appropriateness of the developed algorithms. Further improvements are possible by consideration of long axis images.

1040. A Rician-Gaussian Mixture Model for Segmenting Delayed Enhancement MRI Images Ola Friman1, Anja Hennemuth1, Heinz-Otto Peitgen1 1MeVis Research, Bremen, Germany

A Rician-Gaussian mixture model for segmenting scarred tissue in delayed enhancement MRI images is presented. The parameters in the mixture model are fitted using the Expectation-Maximization algorithm, which also is detailed in the abstract. It is shown that the Rician-Gaussian model fits well, as is predicted by theory. However, partial volume effects due to the large voxel size in delayed enhancement images broaden the fitted distributions. Future work to combat the influence of partial volume effects involves extending the mixture model and introducing spatial context via a Markov Random Field.

1041. Evaluation of Patients with Suspected Cardioembolic Stroke Using Cardiovascular MRI - A Comparative Study with Echocardiography John J. Sheehan1, George Lin1, Jim Conners1, Mark J. Alberts1, Karin Dill1, Reed A. Omary1, Richard A. Bernstein1, James C. Carr1 1Northwestern University, Chicago, USA

CVMR is a non invasive method for the detection of intracardiac thrombi and is clinically advantageous in the detecting non thrombotic findings, including prothrombotic conditions. 106 patients with a suspected CES had CVMR for the detection of intracardiac thrombi. CVMR revealed 10 thrombi in n=9 patients. In 9 patients echocardiography was positive in n=2, indeter. in n=2 and negative in n=5. Additional findings associated with thrombus formation were n=19 (20%) for CVMR and n=7 (7%) for echocardiography. CVMR should be considered as part of the routine evaluation with echocardiography in the assessment of patients with suspected CES.

1042. Correlation and Visualization of Left Atrial Scar Due to Pulmonary Vein Ablation with Recorded Ablation Sites Jason E. Taclas1, John V. Wylie1, Reza Nezafat1, Thomas H. Hauser1, Mark E. Josephson1, Warren J. Manning1, Dana C. Peters1 1Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA

Radio frequency pulmonary vein ablation is a treatment for atrial fibrillation which provides an electrical block between the left atrium and the pulmonary veins. Electroanatomic mapping system CARTOMERGE (Biosense, Webster) records sites of RF application, and registers these sites to angiographic data in real time to help guide the procedure. After the procedure, late gadolinium enhancement (LGE) cardiovascular MR can be used to image scar generated by RF ablation. We have developed a tool using Visual Toolkit (Kitware Inc.) to register electroanatomic mapping data to angiographic data, and render it with LGE scar data.

1043. Application of DE-MRI to Assess the LA Myocardium Composition in AF Patients Robert S. Oakes1, 2, Eugene Kholmovski3, 4, Edward V.R. DiBella3, 4, Nathan Segerson4, Eric Nathaniel Fish4, Christopher J. McGann4, Rob S. MacLeod2, 4, Nassir F. Marrouche5 1University of Utah School of Medicine, Salt Lake City, USA; 2University of Utah, Salt Lake City, USA; 3Utah Center for Advanced Imaging Research, Salt Lake City, USA; 4University of Utah Schol of Medicine, Salt Lake City, USA; 5University of Utah Schol of Medicine, Salt Lake, USA

We report an MRI method to define responders to pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF). Thirty one patients were imaged using a delayed enhancement MRI scan protocol. Novel image processing methods were then applied to visualize and quantify the amount of enhancement in two and three dimensions. Patients with extensive enhancement on MRI were much more likely to suffer recurrence than patients without enhancement. MRI appears to offer a feasible way to define areas of fibrosis in patients with AF and shows great promise in predicting responders to PVI treatment.

Poster Sessions

197

1044. Temporal Evolution of Myocardial Perfusion, Viability and Function After Intramyocardial Transfer of Plasmid DNA Gene Expressing Two Isoforms of Hepatocyte Growth Factor Maythem Saeed1, Alastair J. Martin1, Phlilip Ursell1, Loi Do1, Matthew Bucknor1, Charles B. Higgins1, David Saloner1 1University of California San Francisco, San Francisco, California , USA

Cardiac dysfunction in ischemic cardiomyopathy is most likely due to decreased perfusion and increased collagen synthesis. Therefore, an approach that alters perfusion and fibrosis may open up a new therapeutic avenue. Accordingly, we investigated the angiogenic and antifibrotic effects of intramyocardially delivered hepatocyte growth factor (HGF) gene in acute infarction. Perfusion and viability MR imaging was used to non-invasively assess the therapy. Histopathological methods were used to confirm MR findings. Our novel study demonstrated the biological effects of HGF gene in infarcted myocardium. The beneficial effect of HGF gene includes angiogenesis and formation of peninsulas/islands of viable cells in peri-infarcted myocardium. The MR study provides comprehensive assessment of myocardial perfusion, viability and function after gene therapy.

MR Safety: Fields Hall D Monday 14:00-16:00

1045. SAR and Temperature Compared to Limits in Simulations of a Dedicated Extremity Coil Zhangwei Wang1, Timothy J. Mosher1, Christopher M. Collins1 1Penn State University, Hershey, Pennsylvania, USA

Little information has been published regarding the SAR distributions in extremities using dedicated extremity coils. This has led to gross extrapolations from data calculated for other parts of the body, such as the head, to determine operating limits in extremity imaging. Here we evaluate what RF power levels can be used in imaging of the human knee with a dedicated extremity coil without exceeding IEC or FDA limits on SAR or temperature.

1046. SAR Evaluation of 7.0 Tesla Perfusion Imaging with Arterial Spin Labeling Coil Shumin Wang1, Hellmut Merkle1, Lalith Talagala1 1LFMI/NINDS/NIH, Bethesda, Maryland, USA

We examined the safety of neck labeling coils at 7.0 Tesla by using both numerical simulations and experimental data. This study combines the SAR contribution of a CASL neck labeling coil during RF labeling and that of a volume transmit coil during image acquisition. Results indicate that CASL perfusion with a neck labeling coil will be possible at even higher fields without exceeding the SAR guidelines.

1047. 9.4 T RF Heating: In Vivo Thermoregulatory Temperature Response in Porcine Models Devashish Shrivastava1, Robert Schlentz1, Jeramy Kulesa1, Lance DelaBarre1, Carl Snyder1, Timothy Hanson1, J. Thomas Vaughan1 1University of Minnesota, Minnesota, USA

In vivo thermoregulatory response to RF heating at 9.4 T was studied by measuring temperatures in the heads of eight human-sized porcine models. Temperatures were measured in the scalp and brain by fluoroptic thermometry. Continuous wave RF power was delivered for 2.5-3.4 hours to four anesthetized animals. A four loop head coil was used, which was tuned to 400 MHz. The SAR was maintained close to 3 W/kg. Sham RF was delivered to the other four anesthetized animals to understand the effect of anesthesia on temperatures. Run-away heating response was seen in three out of four RF heated animals.

1048. Proton Resonance Frequency Shift Based NMR Thermometry for Ultra-High Field RF Safety Appl Devashish Shrivastava1, Lance DelaBarre1, Shalom Michaeli1, Carl Snyder1, Timothy Hanson1, J. Thomas Vaughan1 1University of Minnesota, Minnesota, USA

The relative variation in the slopes of proton resonance frequency shift related phase changes was studied over 34.6 and 40.6 C in a non-perfused porcine brain at 7 T. This was done to develop an MR thermometry technique with sub-degree celsius accuracy to measure RF heating in porcine models at ultra-high fields. The phase-change slope varied between (-0.01 ppm/ C) and (-0.015 ppm/ C) in the porcine brain.

1049. Subjective Acceptance of 7T: Initial Experience in the First 210 Subjects Jens Matthias Theysohn1, 2, Stefan Maderwald1, 2, Oliver Kraff1, 2, Christoph Moenninghoff1, 2, Wolfgang P. Becker1, 2, Patrick Kokulinsky1, 2, Michael Forsting1, 2, Mark E. Ladd1, 2, Susanne C. Ladd1, 2 1University Duisburg-Essen, Essen, Germany; 2University Hospital Essen, Essen, Germany

The introduction of ultra high field MRI systems for clinical human imaging leads to a raised consciousness regarding subjective patient acceptance and appearance of side-effects. We present our data collected from the first 210 human subjects undergoing a 7T MRI examination. Following the examination, potential sources of discomfort and side effects were rated on a 10-point scale and documented. General acceptance was high and side-effects tolerable. We believe that the willingness to undergo such an examination will be even higher if medical benefit for the individual is expected. No critical situation occurred.

1050. Lowering the Imager Significantly Reduces the Field Exposure of MRI Occupational Workers Adnan Trakic1, Hua Wang1, Feng Liu1, Hector Sanchez Lopez1, Ewald Weber1, Stuart Crozier1 1The University of Queensland, Brisbane, Australia

In MRI, healthcare workers can be exposed to strong static and time-varying magnetic fields outside the imager, which can lead to the stimulation of electric fields in the body. Tissue of the central and peripheral nervous system (CPNS) in the head and torso is particularly susceptible. Reported is a simple solution that can notably reduce the head/trunk exposure of MRI operators to both static and low-frequency magnetic fields. The numerical results indicate that the upper body CPNS exposure can be reduced by factors of up to 50 or more, when the scanner is lowered by 1 m in height relative to the normal operator position.

Poster Sessions

198

1051. Simple Analytical Equation of the Induced E-Field Esra Abaci1, Emre Kopanoglu1, Vakur Behcet Erturk1, Ergin Atalar1 1Bilkent University, Ankara, Turkey

During MRI, due to the time varying magnetic field, electric field is induced. To derive simplified expression of induced E-field in a cylindrical homogenous volume with radius ρ 0 and conductivity σ the gradient fields are assumed to be uniform. The analytical E-field expression is simplified using low frequency based assumptions. The result satisfies the expected conditions, e.g. the divergence of E-field is zero and also it is in line with our intuitive understanding on what E field should be. With this simplified expression, electric field behavior inside the body can easily be defined without an additional computational work.

1052. Induced Magnetic Forces in the Human Head During MRI Procedures: A Group Analysis Ruiliang Wang1, Dardo Tomasi1, Gene-Jack Wang1, Elisabeth C. Caparelli1, Rita Z. Goldstein1, Nora D. Volkow2, Joanna S. Fowler1 1Brookhaven National Laboratory, Upton, USA; 2National Institutes of Health, Bethesda, USA

Understanding the complex distribution of magnetic field gradients and the induced magnetic forces in human head during magnetic resonance imaging is an important safety issue, particularly for high filed MRI. The magnetic force acting on biological tissues that are exposed to an external magnetic field is proportional to tissue susceptibility and the spatial distribution of the static magnetic field. The aim of this work was to map the magnetic force acting on biological tissues of the human head when the subject’s heads are placed in the homogeneous magnetic field of an MRI scanner for a group of healthy subjects

1053. Tailoring of Gradient Coils for Numerical Exposure Evaluations Based on Experimentally Measured B-Field Feng Liu1, Adnan Trakic1, Hector Sanchez Lopez1, Ewald Weber1, Stuart Crozier1 1The University of Queensland, Brisbane, Australia

Assessment of MRI worker exposures to pulsed magnetic fields produced by gradient coils has recently attracted a lot of awareness in the field of occupational health and safety. To accurately model the exposures, a full three-dimensional distribution of the magnetic field in the vicinity of the magnet end is required. Unfortunately, for many MRI installations, the coil pattern that generates this magnetic field is often not provided by the manufacturer. A method is presented in which the prediction of a current distribution that generates a nearly identical magnetic field pattern is constrained by a number of experimentally measured magnetic field sample points outside the gradient set of interest. The method takes into consideration other important descriptors such as field uniformity in the working volume, gradient coil geometry, driving current, gradient strength, active shielding etc. To demonstrate the application of the method, current density and matching magnetic field distributions of x- and z-axis gradient coils are derived. This enables robust, accurate evaluations of exposures of tissue-equivalent numerical worker models without pre-knowledge of gradient coil patterns.

1054. Tissue-Mimicking Phantoms for a Combined Magnetic Resonance (MR)/ultra-Wideband (UWB) Radar Technique Florian Thiel1, Florian Schubert1, Werner Hoffmann1, Frank Seifert1 1Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany

Our research is aimed towards the synergetic technological development of ultra-broadband (UWB) sounding combined with magnetic-resonance imaging (MRI), to access innovative fields of application such as the imaging of cardiac blood vessels and heart beat monitoring, accurate modelling of electromagnetic wave propagation through heterogeneous, malignant and benign, biological tissue for high-field MRI, and fast and precise identification and localisation of breast cancer. As our first step towards this ambitious aim we report on moveable multilayer tissue-like phantoms specifically designed for testing and development of a UWB-MRI combination setup.

1055. MRI Safety: Quantitative Comparison of RF-Heating on Different MR Scanners Based on the High Frequency B1-Field Florian Fidler1, Toni Hippmann2, Marcus Warmuth3, Philipp Ehses4, Peter Nordbeck3, Michael T. Friedrich5, Wolfgang Geistert5, Walter Kullmann2, Peter Michael Jakob, 14, Wolgang Rudolf Bauer3 1Research Center Magnetic-Resonance-Bavaria, Würzburg, Germany; 2Fachhochschule Würzburg-Schweinfurt, Schweinfurt, Germany; 3University Hospital Würzburg, Würzburg, Germany; 4University of Würzburg, Würzburg, Germany; 5Biotronik GmbH & Co. KG, Berlin, Germany

The understanding of heating effects in MRI, especially in patients with medical implants, is one of the most important issues in MRI safety. Local electric fields are known as the cause of implant heating, but these are in general not accessible. The vast majority of the electric field is induced from eddy currents generated by the high frequency magnetic B1-field. The purpose of this work was to give a quantitative comparison of SAR maps and therefore heating results on different MRI systems and a simulation based on the knowledge of the B1-field.

MR Safety: Devices Hall D Tuesday 13:30-15:30

1056. Updated Overview: Marking and Testing Standards for Magnetic Resonance (MR) Safety and Compatiblity of Items/Devices Used in MR Environments Gregor Schaefers1 1MR:comp GmbH, Gelsenkirchen, Germany

MR safety and image compatibility are internationally recognized as important issues for medical devices. Medical devices and items that can be exposed to an MR environment must be tested on magnetically induced forces, torques, RF heating, induction of voltages and safe functioning as well as MR image artifacts. First standardized test methods were already established. Further standard development is necessary in order to minimize patient risk and guiding device manufacturers in development of MR safe devices as well as supporting the MR user with meaningful experimental results.

Poster Sessions

199

1057. Material- And B0-Dependent Scaling of Torque Effects Roger Luechinger1, Volkert A. Zeijlemaker2, Maarten van Bentem2, Firat Duru3, Peter Boesiger1 1Institute for Biomedical Engineering, University and ETH, Zurich, Switzerland; 2Medtronic Inc., Netherlands; 3University Hospital, Zurich, Switzerland

The scaling with the main magnetic field strength of torque effects on different materials (NdFeB magnet, nickel plate, and Dysprosium sulfate) and on a medical device (Reveal loop recorder) have been investigated. The measurements have been performed at 0.15T, 0.5T, 1T, 1.5T, 3T, and 7T. For ferromagnetic material maximal torque will not change, above its saturation point. Saturation will occur in most ferromagnetic materials in the range of 0.2-1T. Torque on magnets will increase linearly with the main magnetic field strength.

1058. Torque Measurements in MRI Safety Testing Nikolaus M. Szeverenyi1, Mugdha Thakur2 1SUNY Upstate Medical University, Syracuse, New York, USA; 2Syracuse University, Syracuse, New York, USA

ASMT standard F2213-04 specifies how torque measurements are to be obtained in static magnetic fields using a torque balance, but there exists very little literature from investigators actually using such a device. Instead approximations involving rotation of the ferro-metallic sample on a plastic surface or other qualitative observations are usually employed. We describe the fabrication and use of several modified versions of the ASTM torque balance that will be appreciated by the MRI safety testing community. The origins of this force and its field dependence are also investigated.

1059. An EEG System with Carbon Wire Electrodes and an Anti-Polarization Circuit for Simultaneous EEG-FMRI Recording Michiro Negishi1, Ilan Laufer1, Mark Abildgaard1, Terry Nixon1, Robert Todd Constable1 1Yale University, New Haven, Connecticut, USA

Simultaneous EEG-fMRI (Electroencephalography-functional Magnetic Resonance Imaging) recording offers high temporal resolution electrophysiological recording and high spatial resolution hemodynamic recording from the same experimental runs. Carbon wire electrodes (not solid electrodes with carbon leads) are suitable for simultaneous EEG-fMRI recording because they cause less radio frequency heating and less susceptibility artifacts than metallic electrodes. However, carbon wire electrodes have not been used widely in human EEG because of the electrode polarization, or imbalance of DC potentials among electrodes. In this study, we developed and evaluated a prototype EEG system with carbon wire electrodes and a pre-amplifier equipped with an anti-polarization mechanism.

1060. Safety of Localising Intracranial EEG Electrodes Using MRI: A Comparison Between Head and Body Coils at 3T David William Carmichael1, John S. Thornton2, Philip J. Allen2, Louis Lemieux1 1UCL Institute of Neurology, London, UK; 2National Hospital for Neurology and Neurosurgery, London, UK

The safety of post-implantation localisation of intracranial EEG electrodes by MRI was investigated for body and head coils at 3T using a test object with a combination of electrodes simulating a clinical arrangement and a high SAR sequence. For head coil RF-transmission moderate heating was observed (<2ºC) under ‘standard’ conditions, with the external electrode leads (tails) separated, increasing with the tails in electrical contact. Conversely, for body coil RF–transmission, heating was markedly higher (+6.4ºC) with the tails separated. MRI with intracranial EEG electrodes at 3T can be safe, providing SAR is restricted and a head transmit coil is used.

1061. Estimating Specific Absorption Rate (SAR) During MRI in the Human Brain with Intracranial EEG Electrodes Used for Epilepsy Monitoring: A Preliminary Study Using Finite Integral Technique (FIT) Modelling David William Carmichael1, Yan Li2, Andrew McEvoy3, Jeff W. Hand2, 4, Louis Lemieux1 1UCL Institute of Neurology, London, UK; 2Imperial College, London, UK; 3National Hospital for Neurology and Neurosurgery, London, UK; 4Imperial College Healthcare NHS Trust, London, UK

A commercial EM solver was used to model the interaction between an MRI head coil and the human head with a subdural-grid implant used for epilepsy monitoring. The electric field was found to be focused around the implant, with much greater values than seen in the head without the implant. However, when SAR was averaged over both 1g and 10g masses the peak local SAR proximal to the implant increased but the position of maximum local SAR produced (in the sinus region away from the implant) was not altered.

1062. Heating Effects Measured in EEG Electrodes at 3T Ruth L. O'Gorman1, 2, Laura A. Wherity3, Sophie F. Riches4, Owen G. O'Daly2, Dominic H. ffytche2 1King's College Hospital, London, UK; 2Institute of Psychiatry, London, UK; 3King's College Hospital, UK; 4Institute of Cancer Research, London, UK

The simultaneous acquisition of EEG and fMRI data provides a unique opportunity for investigating cerebral function at high spatial and temporal resolution, but simultaneous EEG-MRI raises several patient safety issues. This study investigated the heating effects from several MRI pulse sequences in EEG electrodes placed in a variety of locations and orientations. A maximum temperature rise of 1.44 ºC was recorded, but the time course of the temperature measurements suggests that greater temperature rises may be likely if high-SAR sequences are applied consecutively. In addition, a large variation in recorded temperature change was observed across different electrode positions and orientations.

1063. Improved RF Safety of Interventional Devices Using Cable Traps Krishna N. Kurpad1, Erik T. Bieging1, Orhan Unal1, 2 1University of Wisconsin , Madison, USA; 2University of Wisconsin - Madison, Madison, USA

RF safety is a major concern in the design of active tracking and imaging devices for MR guided interventions. In this work, we demonstrate the potential of simple coaxial cable traps in suppressing RF heating to acceptable levels.

Poster Sessions

200

1064. Reduction of RF Heating of Interventional Cryoprobes Using Chokes Sonal Josan1, Ronald Watkins1, Bruce Daniel1, Kim Butts Pauly1 1Stanford University, Stanford, California , USA

In presence of electrically conductive structures, such as implants, wires, or interventional devices, radio-frequency fields used in MRI can cause significant heating of the surrounding tissue. The magnitude of the heat depends on the device geometry, position within the patient, and position relative to the RF coil electric field. These effects have been described for guidewires at 1.5T and higher. The purpose of this work is to show resonant RF heating from a cryoablation device at 0.5T, to determine the safe & worst-case configurations, and demonstrate the use of RF chokes to reduce unwanted currents on the cable that lead to tissue heating.

RF Coils for Human Imaging Hall D Wednesday 13:30-15:30

1065. Separate Transmit and Receive Arrays for 7T Body Imaging Carl Jason Snyder1, Lance DelaBarre1, Greg Metzger1, Can Akgun1, Patrick Bolan1, Kamil Ugurbil1, Thomas Vaughan1 1University of Minnesota, Minneapolis, USA

It is known that using separate volume transmit coil with local phased array receivers has benefits over using either coil separately. Unfortunately, most body imaging at 7T currently uses surface transceive arrays. We have designed an 8 channel TEM transmit array to be used in conjunction with a 16-channel loop receiver array and a B1+ shimming algorithm for body imaging at 7T. This combination provides a relatively homogeneous volume over a localized region in the body.

1066. Rotating Transmission Line Elements for Optimized Parallel Imaging Zhangwei Wang1, Michael Craig1, Ye Li2, Qing X. Yang1, Christopher M. Collins1, Wei Chen2 1Penn State University, Hershey, Pennsylvania, USA; 2University of Minnesota, Minneapolis, Minnesota, USA

For transmit arrays, independent amplitude and phase control can be used in a variety of ways achieve a homogeneous excitation distribution. However, for a receive array manipulation of sensitivity distributions and the g-factor require variation of the coil geometry. Stemming from work with stripline transmission line elements, we propose a new type of transmission line element which can be used to optimize the field distribution and g-factor easily by adjusting the orientation of independent coils.

1067. Shielded Quadrature Coil Elements for NMR Phased-Arrays Matthias F. Mueller1, 2, Titus Lanz2, Tobias Wichmann2, 3, Felix A. Breuer3, Mark A. Griswold4, Peter M. Jakob1 1University of Wuerzburg, Wuerzburg, Germany; 2Rapid Biomedical GmbH, Rimpar, Germany; 3Research Center Magnetic Resonance Bavaria (MRB), Wuerzburg, Germany; 4University Hospitals of Cleveland, Cleveland, Ohio, USA

Recently MR systems with 128 independent receiver channels have been developed. With these, phased-arrays with up to 128 coil elements have been introduced. While these arrays have provided impressive results, the minimal size of elements is limited if maintaining sample noise dominance is required. Thus, only a fraction of the receive channels can be used to full potential for imaging of more localized region-of-interests. To this end, the concept of shielded quadrature array coil elements is introduced which utilizes additional, perpendicular coil elements to improve signal-to-noise ratio and encoding capability for parallel imaging.

1068. A Novel Decoupling Technique for Non-Overlapped Microstrip Array Coil at 7T MR Imaging Zhentian Xie1, Xiaoliang Zhang1, 2 1UC San Francisco, San Francisco, California , USA; 2UC Berkeley Joint Graduate Group in Bioengineering, San Francisco & Berkeley, California , USA

. In this work, a new magnetic wall decoupling method for designing non-overlapped coil arrays is introduced by using microstrip lines. The micsrotrip lines are the magnetic-wall generators, laced between two adjacent resonant coil elements. There is no physical connection between the decoupling microstrip line and coil elements. Theoretically this method is not frequency-sensitive, therefore the decoupling performance can be maintained in a broad frequency range. Bench test and preliminary imaging results are shown, using the proposed coil array at 7T. The MR images from each resonant element have no signal is observed from other coil, indicating the effectiveness of the proposed decoupling technique at ultrahigh field of 7T. The proposed design provides a robust approach to design of parallel imaging arrays at ultrahigh fields.

1069. 1.5-Tesla Integrated Dual Mode Hand/Wrist Array Coil for Imaging Jacob Weaver1, Joseph Herczak1, Tsinghua Zheng1, Xiaoyu Yang1, 2, Hiroyuki Fujita1, 2 1Quality Electrodynamics, LLC., Mayfield Village, USA; 2Case Western Reserve University, Cleveland, USA

A six-channel dual-mode array coil for hand/wrist MRI imaging at 1.5 Tesla was constructed and tested. The coil offers two variable FOV modes, a full mode with an S-I coverage of 20cm for the entire hand/wrist imaging and a magnifying FOV mode covering 10cm in S-I for high resolution wrist only imaging. The high resolution mode shows significant SNR gains in the wrist region compared to a commercially available QD wrist coil.

1070. 8 Channel Multi-Coil to Image Both Hands and Both Wrists Symmetrically for RA Diagnosis Akira Nabetani1, Harushi Mori2, Atsushi Nozaki1 1GE Yokogawa Medical Systems, Ltd., Hino, Japan; 2University of Tokyo, Bunkyo-ku, Japan

8 channel muti-coil to image both hands and both wrists symmetrically for Rheumatoid Arthritis (RA) diagnosis was designed and developed. At first patientfs posture for symmetrical imaging of both hands and both wrists in comfortable manner was considered. Then holding fixture was designed to keep such posture stably and comfortably. 8 coil element size and layout was determined for the B1 sensitivity of the multi-coil to cover the area of both hands and both wrists as homogeneously as possible. The developed holding fixture had stable and comfortable holding capability so there were no apparent motion artifacts in the images.

Poster Sessions

201

1071. Twelve-Channel Receive-Only MRI Breast Coil at 3T John A.J. de Groot1, Dennis W.J. Klomp2, Evert G.J. Beerens1 1Machnet BV, Maarn, Netherlands; 2Radboud UMC Nijmegen, Nijmegen, Netherlands

In this study we show simulation results of a twelve-channel MRI breast coil at 3T and measurements with phantoms and volunteers. The system consists of an existing 4-channel breast coil and a newly designed 8-channel add-on coil. The goal was to increase acquisition speed without compromising SNR compared to the existing breast coil. High reduction factors can be achieved by keeping coil couplings low and maintain good g-factor maps. We show that the system SNR is improved significantly and that high reduction factors can be applied.

1072. Central and Peripheral SNR as a Function of Number of Active Coils for 32 and 96 Channel Receive Coils at 3 Tesla Graham C. Wiggins1, Jonathan Polimeni1, Andreas Potthast2, Thomas Witzel1, Lawrence L. Wald1, 3 1Massachusetts General Hospital, Charlestown, Massachusetts, USA; 2Siemens Medical Solutions,Inc, Charlestown, Massachusetts, USA; 3Harvard-MIT Division of Health Sciences and Technology, Cambridge, Massachusetts, USA

When using arrays with large numbers of small coils there is commonly a concern about the sensitivity provided by the small elements at distances farfrom the array. It is important to understand how the SNR in the center of the sample increases as a function of the number and distribution of coil elements around the head, whether in fact the SNR may decrease beyond a certain number of coils, and therefore how much benefit is gained from costly and complicated designs with 96 channels or more. We find particular benefit from the coils arranged over the dome of the head in our high-N arrays even for central SNR.

1073. Noise Correlation and Coupling Mechanisms: A Comparison of Overlapped and Non-Overlapped Surface Coils at 3T Nicola De Zanche1, Jurek Antonin Nordmeyer-Massner1, David Otto Brunner1, Klaas Paul Pruessmann1 1University and ETH Zurich, Zurich, Switzerland

Overlap is commonly used to minimize mutual inductance, and thereby coupling, among nearest neighbors in a coil array. In parallel imaging, however, it has been shown that non-overlapped coils provide more favorable sensitivity profiles than their overlapped counterparts. We provide data that demonstrate a clear advantage of non-overlapped over overlapped coils also in terms of noise correlation among channels when effective preamplifier decoupling provided by standard techniques is present.

1074. Approaching Ultimate SNR and Ideal Current Patterns with Finite Surface Coil Arrays on a Dielectric Cylinder Riccardo Lattanzi1, 2, Aaron K. Grant2, 3, Daniel K. Sodickson4 1Harvard-MIT, Cambridge, Massachusetts, USA; 2Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA; 3Harvard Medical School, Boston, Massachusetts, USA; 4New York University Medical Center, New York, New York, USA

In this work we compare the SNR and current patterns of realistic coil models with the ultimate intrinsic SNR and the corresponding ideal current patterns for a homogeneous cylindrical sample. Calculations were repeated at different magnetic field strengths and for various acceleration factors, using coil arrays with increasing numbers of elements, in order to investigate how rapidly the ultimate behavior was approached in each case. In the center of the sample, 128-element arrays reached approximately 90% of the optimum SNR at 1.5T, whereas performance was lower at higher field strength due to increasing complexity in the ideal current patterns.

1075. Empirical Validation of 3T 96 Channel G-Factors and Comparison to Ultimate G-Factor Graham C. Wiggins1, Jonathan R. Polimeni1, Andreas Potthast2, Thomas Witzel1, Lawrence L. Wald1, 3 1Massachusetts General Hospital, Charlestown, Massachusetts, USA; 2Siemens Medical Solution, Inc, Charlestown, Massachusetts, USA; 3Harvard-MIT Divisions Of Health Sciences and Technology, Cambridge, Massachusetts, USA

Accelerated imaging performance is one of the primary motivators for the development of receive arrays with higher and higher numbers of elements, typically characterized by the SENSE G-factor Metrics such as the maximum or the mean G-factor for a particular acceleration rate are frequently given as a key characteristic of a particular coil array. In practice, there are many factors which can influence the calculated G-factor map, including the field of view relative to object size (which determines the degree of aliasing), noise level and degree of smoothing in the sensitivity profiles, and whether regularization is used. We use time series data to validate analytical G-factor values for a 3T 96 Channel coil and compare these to the Ultimate G-factor. The 96 Channel coil appears to approach the ultimate G-factor for accelerations up to R=6

1076. A 1.5T 32-Channel Cardiac Array Coil for Coronary and Whole Heart MRI Hiroyuki Fujita1, 2, Tsinghua Zheng1, Xiaoyu Yang1, 2, Joseph Herczak1, Jacob Weaver1, Kazuya Okamoto3, Takahiro Ishihara3 1Quality Electrodynamics, LLC., Mayfield Village, USA; 2Case Western Reserve University, Cleveland, USA; 3Toshiba Medical Systems Corporation, Otawara, Japan

MRI provides unparalleled soft-tissue contrast, and the temporal resolution has been much improved because of the rapid developments of high channel receiver count MRI hardware system and sophisticated parallel imaging applications. These state-of-the-art parallel imaging technologies enable effective real-time MR cardiac imaging. In this work, the authors constructed and tested a 1.5T 32-channel cardiac array, which is capable of higher acceleration factors to advance coronary and whole heart MRI.

1077. A 3D Parallel Imaging Capable Transmit and 15-Channel Receive Array Knee Coil at 3T Matthew Finnerty1, Joseph Herczak1, Tsinghua Zheng1, Jacob Weaver1, Xiaoyu Yang1, 2, Hiroyuki Fujita1, 2 1Quality Electrodynamics, LLC., Mayfield Village, USA; 2Case Western Reserve University, Cleveland, USA

While knee imaging at 3T offers advantages over 1.5T in regards to greater spatial resolution and higher SNR, current commercial knee coils are susceptible to pulsation/flow artifacts since they only have one row of elements in the S-I direction. To address these challenges, a 15-channel knee coil with local 12-rung birdcage transmitter has been developed that utilizes three rows of elements in the S-I direction, which allows for 3D parallel imaging while providing high SNR and good uniformity with a larger coil inner diameter.

Poster Sessions

202

1078. SENSE Optimized Sixteen Element Receive Array for Cervical Spinal Cord Imaging at 3T Jerzy Bodurka1, Patrick Ledden2, Peter Bandettini1 1National Institute of Mental Health, NIH, Bethesda, Maryland, USA; 2Nova Medical Inc., Wilmington, Massachusetts, USA

High quality and high resolution anatomical and functional imaging the human spinal cord remains a significant challenge in MRI. The benefits of parallel imaging with surface coil arrays have been clearly shown particularly in the brain imaging for both anatomical and fMRI studies. Here we demonstrate a custom design and build of a sixteen element receive-only surface coil array for spinal cord MRI imaging at 3 Tesla.

1079. Coil Design for Highly Accelerated 2D SENSE MRA of the Lower Legs Casey P. Johnson1, Clifton R. Haider1, Phillip J. Rossman1, Thomas C. Hulshizer1, Eric A. Borisch1, Stephen J. Riederer1 1Mayo Clinic, Rochester, Minnesota, USA

Typical acceleration directions for 2D SENSE of the legs are left-right (L/R) and anterior-posterior (A/P). However, the fields of view along these directions can differ by a factor of three. In this work we describe an eight-element array in which the A/P elements are designed to have reduced depth of response compared to the L/R elements to account for the FOV differences. Compared to an eight-element array with uniformly-sized elements, the new design typically provides a 25% reduction in g-factors for acceleration factors >7. 2D SENSE CE-MRA of the lower legs at these high accelerations is of high quality.

1080. SNR and Parallel Imaging Performance of a 32-Channel Array for Human Brain Imaging at 7 Tesla Jacco A. de Zwart1, Peter van Gelderen1, Shumin Wang1, Jeff H. Duyn1 1National Institutes of Health, Bethesda, Maryland, USA

Multi-channel coil arrays have led to substantial sensitivity and resolution improvements in human brain MRI. These benefits generally increase with the number of coil elements but level off at large element counts. An increased number of array elements also increases parallel imaging (PI) performance. Data from a 32-channel array at 7T were compared with a simulation and with numerically derived lower element count arrays to investigate these two aspects. SNR improves about a factor of 4 on average over the brain compared to one channel. Up to ~6-fold acceleration can be achieved with a mean PI penalty of <~20%.

RF Transmit Array Methods Hall D Thursday 13:30-15:30

1081. Analysis of Coil Configurations for Transmit SENSE Glen Morrell1 1University of Utah, Salt Lake City, USA

A framework is presented for evaluation of coil configurations for transmit SENSE. For subsampled Cartesian k-space, a matrix A of coil sensitivity values is inverted at each spatial location to calculate the individual per-coil excitation profiles which add to give the desired excitation. We show through mathematical analysis and Monte Carlo simulation that the condition number of A, evaluated point by point in the spatial domain, is a good measure of the fidelity of excitation that can be achieved by a transmit SENSE coil configuration in the presence of noise in the coil sensitivity profiles.

1082. Q Measurement and Simulation for RF Coils Geoff Jacobs1, Abel Assefa1, Jacob Willig-Onwuachi1 1Grinnell College, Grinnell, USA

While Q measurements are used widely to characterize RF coils and the theory involved is well understood, there is surprisingly little literature on how to most accurately perform these measurements. This project is an initial attempt to compare several common methods of measuring Q with each other and with expected theoretical results. A basic model for simulation is presented.

1083. Selective Excitation Without Gradients with Accelerated TRASE Jonathan C. Sharp1, Scott B. King2, Donghui Yin2, Vyacheslav Volotovskyy2, Boguslaw Tomanek1 1National Research Council Institute for Biodiagnostics, Calgary, Canada; 2National Research Council Institute for Biodiagnostics, Winnipeg, Canada

The abstract shows how slice selection can be achieved using only pair of RF coils and a single-channel transmitter system. This method uses two or more uniform amplitude RF volume coils designed with B1 phase gradients. A train of refocusing pulses, applied alternately between the two coils, provides a k-space trajectory. Interleaved small tip angle pulses with a sinc envelope results in slice selection. In addition, the method may be accelerated to reduce the echo train length by use of two or more coils for the small tip angle pulses following each refocusing pulse.

1084. B1-Shimming at 3T Using an 8-Channel Transmit Array Scott B. King1, Mike J. Smith1, Ulrich Fontius2, Peter Latta1, Jarod Matwiy1, Franz Schmitt2, Boguslaw Tomanek1 1Institute for Biodiagnostics, Winnipeg, Canada; 2Siemens Medical Solutions, Erlangen, Germany

B1-shimming can be accomplished with hardware-only using a transmit-array with appropriately driven amplitude and phase of each array element, or using 2D/3D RF spatially selective pulses. On a new Siemens 8-channel transmitter 3T Trio-Tim MRI system, we have shown that B1-shimming using the hardware approach using an azimuthal distribution of array elements is unable to adequately achieve uniform excitation and therefore future Tx-array coils will require elements to be placed along the axis of the coil as well. 2D/3D RF pulses can effectively produce uniform excitation but require Tx-arrays (Tx-SENSE) to minimize acceptable pulse lengths.

Poster Sessions

203

1085. B1 Transmit Field Correction at 7T Using Coupled Inner Elements Hellmut Merkle1, Shumin Wang1, Peter van Gelderen1, Tie Q. Li1, Joseph Murphy-Boesch1, Alan P. Koretsky1, Jeff H. Duyn1 1National Institutes of Health, Bethesda, Maryland, USA

Multiple resonant loop elements placed within the interior of a circularly polarized volume transmit coil have been used to modify the field profile over a conductive phantom. The phantom has been filled with low dielectric material and saline to approximate the dielectric and conductive properties of the head. A B1 mapping sequence has been used to provide quantitative information about the modified transmit B1 field.

1086. Improved Parallel Imaging Using Small FOV Excitation on an 8-Channel Transmit Array System Mike J. Smith1, Scott B. King1, Peter Latta1, Jarod Matwiy1, Ulrich Fontius2, Franz Schmitt2, Boguslaw Tomanek1 1National Research Council Institute for Biodiagnostics, Winnipeg, Canada; 2Siemens Medical Solutions, Erlangen, Germany

Transmit array systems can generate better 2D excitation profiles in shorter time than single channel transmitters. We used our new 3T Siemens 8-channel transmit system in enhancing parallel imaging when the sample exceeds the ROI. When excitation artifact signals are below the image noise level, g-factor maps are significantly improved, and effective reduction factors larger than the receive array are possible.

1087. Subject-Dependent Optimization of Parallel RF Transmission for High-Field MRI Yeun Chul Ryu1, Jung Ho Hyun1, Jong Soek Oh1, Yong Gwon Kim1, Soo Yeol Lee2, Heung Kyu Lee3, Chang Hyun Oh1 1Korea University, Seoul, Republic of Korea; 2Kyung-Hee University, Suwon, Republic of Korea; 3KAIST, Dae-jeon, Republic of Korea

A Subject-dependent rapid RF field mapping method for parallel RF transmission.

1088. Transmit B1 Shimming at High Field with SAR Constraints: A Two Stage Optimization Method Independent of the Initial Set of RF Phases and Amplitudes Tsung-Hui Chang1, Zhi-Quan Luo1, Xiaoping Wu2, Can Akgun2, Thomas Vaughan2, Kamil Ugurbil2, 3, Pierre-Francois Van de Moortele2 1University of Minnesota, Minneapolis, Minnesota, USA; 2University of Minnesota Medical School, Minneapolis, Minnesota, USA; 3Max Planck Institute for Biological Cybernetics, Germany

There has been an increasing interest in constraining transmit B1 shimming with specific absorption rate (SAR) limits, especially at high magnetic field. Since most of the existing methods rely on solving a nonconvex optimization problem, they are typically faced with two difficulties: Only local optimum solutions are obtained, and they are susceptible to the chosen initial points for optimization. Here we introduce a two stage optimization method where a reliable initial point is acquired in the first stage by a convex semidefinite relaxation (SDR) approximation method. A high quality B1 shimmed map then can be obtained in the second stage optimization using the SDR initial points. The presented technique is verified with simulations for a 16-channel transmit coil array at 7T with a human head model.

RF Transmit Array Hardware Hall D Monday 14:00-16:00

1089. Suppressing Transmit Coil Load Change Effects with Ultra-Low Output Impedance RF Power Amplifier Xu Chu1, Juan Sabate2, Yudong Zhu2 1GE Global Research Center, Shanghai, People's Republic of China; 2GE Global Research Center, Niskayuna, New York, USA

Current variation in a transmit coil due to load change can be substantial in a setup using a conventional RF power amplifier. The capability of a newly developed ultra-low output impedance RF power amplifier in suppressing such current variation is explored. The new amplifier, when connected to drive a transmit coil with L-type input-matching network, acts approximately as a current source, suppressing current variation due to load change and/or EM coupling. Meanwhile, the output-matching network of the MOSFET transforms the input impedance of the coil into the optimum load of the MOSFET, hence maximizing the available output power.

1090. An Integrated Multi-Channel RF Transmitter for Continuous Arterial Spin Labeling with Multiple Label Coils Adam Martin Winchell1, 2, Ralf Berthold Loeffler1, Yong Zhang1, Ruitian Song1, Kathleen J. Helton1, Lawrence L. Wald3, Claudia Maria Hillenbrand1 1St. Jude Children's Research Hospital, Memphis, Tennessee, USA; 2University of Memphis and UTHSC Joint Biomedical Engineering Program, Memphis, Tennessee, USA; 3Massachusetts General Hospital, Charlestown, Massachusetts, USA

A complete territorial brain perfusion system was developed using three independent surface-coils for the left, right carotid and vertebral arteries. Three independent trigger signals controlled by the sequence program gated a single external RF pulse to apply flow-driven adiabatic spin inversion for imaging. This low cost approach was demonstrated in both phantom and volunteer measurements. The volunteer measurements produced well-defined and localized territorial perfusion images which correspond with expected normal physiological conditions.

1091. RF Current Source Development for Parallel Transmit Arrays Using a High Power MOSFET WonJe Lee1, Eddy B. Boskamp, Thomas M. Grist, Krishna N. Kurpad 1Uinversity of Wisconsin-Madison, Madison, USA

RF current source technology is gaining ground in parallel transmit arrays in order for B1 field pattern and local SAR control in high fields. In this work we present a RF current source development using a high power MOSFET by means of driven current amplitude and suppression of current induced by a neighboring element. Experimental results demonstrate improved craven current efficiency and reliability against load impedance changes. Simultaneously, current induced by a neighboring element is suppressed by a factor of 17 dB at the closest loop to loop distance by shunting the output capacitance of the chosen MOSFET.

Poster Sessions

204

1092. Design of a Strip Transmit Coil/Array for Low Field Open MR Bing Wu1, 2, Jun Gao1, Jiabin Yao1, Cunli Zhang1, Xiaoliang Zhang2, 3 1GE Healthcare, Beijing, People's Republic of China; 2UCSF, San Francisco, California , USA; 3UCSF/UC Berkeley Joint Graduate Group in Bioengineering, San Francisco & Berkeley, California , USA

RF coils with microstrip transmission line structure have shown the advantages for high and ultrahigh field MRI due to the excellent high frequency performance. In this work, we explore the feasibility of transmit body coil or coil array design using microstrip design technique for low-field open MR applications. Result shows that the proposed microstrip transmit (Tx) coil or parallel transmit array appears to be more compact and efficient than the conventional saddle-type transmit coils.

1093. An 8 Channel TX-RX Head Array for Improved SNR at 3T Frank Resmer1, Markus Klarhöfer2, Titus Lanz1 1Rapid Biomedical GmbH, Rimpar, Germany; 2University of Basel, Basel, Switzerland

The design of an 8 channel TX-RX Array for 3T is described. It provides an SNR comparable to a volume coil of similar dimensions. Sufficient decoupling between elements is vital with TX-RX arrays. So far TX-RX arrays have been built with strip lines or gap designs to decouple individual elements. These approaches provide good intrinsic decoupling but also reduce the coil sensitivity. The coil presented here uses a conventional design with a capacitive decoupling network and so combines a high SNR with good element decoupling.

1094. Efficiency of a 3T Whole Body 16 Channel TEM Transmit Array Ed Boskamp1, Scott Lindsay1, Patrick Gross2, Hans-Peter Fautz2, Mika Vogel2, John Lorbiecki1, Yudong Zhu3 1GE Healthcare, Waukesha, Wisconsin, USA; 2GE Research, Munich, Germany; 3GE Research, Niskayuna, New York, USA

A 3T whole body 16 channel TEM style transmit array was built and compared to an 8 loop whole body transmit array. The new 16 channel version has an efficiency of 0.231 uT /ãW of B+1 in the center of the coil when driven in an emulated homogeneous birdcage mode. The new array displays lower temperature than the 8 loop design. This array is connected to an 8 channel transmit chain. Each channel is sending power via splitter to 2 rungs, which can be opposite (180 degree phase difference) or neighboring (22.5 degree phase difference)

1095. 7 Tesla Localized RF Excitation/Reception Using a Highly Coupled Coil and Without B1 Measurements Tamer S. Ibrahim1, YiK-Kiong Hue1, Lin Tang2 1University of Pittsburgh, Pittsburgh, Pennsylvania, USA; 2University of Oklahoma, Norman, Oklahoma, USA

The presented results demonstrate that by properly modeling the load, transmit/receive array, and the excitation/reception scheme, an RF power-controlled B1 shimming can be 1) guided with simulations that require a minimum of computational time required (seconds) and 2) efficiently implemented without any B1 measurements. Localized excitation/reception is demonstrated using a 7T system.

1096. Evaluation of a Phase Shifting Matrix for Body Coil B1+ Shimming in a Dielectric Phantom Elisabeth Beermann1, Patrick Gross2 1GE Healthcare, Solingen, Germany; 2GE Global Research, Munich, Germany

One challenges in high field MRI is the B1-field inhomogeneity due to particular patient RF permittivity. This results in artifacts in the MR images and thus can compromise their diagnostic value. RF shimming and parallel transmit offer a potential solution to this challenge. In order to interface an 8-channel system with a 16-channel transverse-electromagnetic (TEM) body-array, the use of a phase shifting or Butler matrix was investigated and B1 shimming in a dielectric phantom was performed. The results for a dielectric phantom thus indicate that the advantages of using a phase shifting matrix are similar to those in a non-dielectric phantom previously published.

1097. Preamp-Like Decoupling and Amplitude Modulation in CMCD Amplifiers for Transmit Arrays Jeremiah Aaron Heilman1, Natalia Gudino, Matthew J. Riffe, Markus Vester2, Mark A. Griswold 1Case Western Reserve University, Cleveland, Ohio, USA; 2Siemens Medical Solutions, Erlangen, Germany

Development of current-mode class-D amplifier, including improvements for amplitude modulation, greater efficiency, and decoupling.

RF Coils for Animal Imaging Hall D Tuesday 13:30-15:30

1098. Solenoidal Out-Of-Plane Micro Coils for MR Analysis Manufactured with a Wire Bonder Kai Kratt1, Ulrike Wallrabe1, Jan G. Korvink1 1University of Freiburg - IMTEK, Freiburg, Germany

We present the development of 3 D solenoidal micro coils for MR analysis based on an automatic wire bonder. By developing a stable and repeatable bond process with insulated wire, micro coils with sub millimeter diameter have been manufactured. The winding process for a single coil takes about 200 ms, whereas the manufacture of a 100 coil array takes less than a minute. Micro coils with 4 windings and inner diameter of 200 µm exhibit an inductance of 12.7 nH and a resistance of 580 mΩ at 300 MHz. A quality factor of 41 enables high-resolution MRI/NMR.

1099. An Inductively Decoupled Coil Array for Parallel Imaging of Small Animals at 7T George Carlos do Nascimento1, Fernando Fernandes Paiva1, Afonso C. Silva1 1National Institutes of Health, Bethesda, USA

A two channel small animal coil array for 7T was designed based upon the method of inductive decoupling between the channels. The level ofisolation can be adjusted by adjusting the coupling in the passive transformer.The method shows a very nice immunity to standing waves, cross talking effects and otherparasitic signals in the array channels. The acquired images shows also that the method provides a good signal to noise ratio.

Poster Sessions

205

1100. A 4-Channel Transceive Surface Coil Array for Small Animal Imaging at 9.4T Samuel O. Oduneye1, 2, Ravi S. Menon1, 2 1The University of Western Ontario, London, Canada; 2Robarts Research Institute, London, Canada

As operational frequencies increase linearly with higher static fields, the wavelength approaches the size of the sample being imaged. The resulting standing wave mode deteriorates image homogeneity. With phased array surface coils, the produced B1 field can be tailored to overcome the so called ‘dielectric resonance effect’, high RF power deposition and signal radiation losses. Here we present a novel high field transceive surface coil array for small animal imaging at 9.4T. Additionally, this design allows the coil to be employed for fast parallel imaging techniques while maintaining the high signal to noise ratio inherent advantage of surface coil designs.

1101. Modular 4-Element Coil Array Constructed of Simple Coil Loops Without Extra Shielding for the Simultaneous MRI of Multiple Small Animals Stefan Fischer1, Florian Martin Meise1, Andrea Kronfeld1, Beat Alessandri1, Wolfgang G. Schreiber1 1Mainz University Medical School, Mainz, Germany

Animal models with small animals like rats and mice are common in the research on diseases and its treatment. For those studies the simultaneous examination of multiple small animals is preferable to avoid an overall long scan time for large numbers of animals. A design without shielding, resulting in an inexpensive and simple array construction, allows time effective building of individual coil setups. Theoretically it can be expanded with further elements for multi channel receive systems up to 32 channels, if state-of-the-art scanner technology is used.

1102. Four Channel Array for 9.4T Animal Studies Christopher Joseph Wargo1, John C. Gore1, Malcolm J. Avison1 1Vanderbilt University, Nashville, Tennessee, USA

Parallel arrays are commonly used in human clinical MR studies due to the benefits they provide. Beyond SNR improvement compared to a volume coil, parallel arrays support rapid imaging methods such as SENSE. The reduced scan time can be used to improve experiment efficiency, increase resolution, or help reduce field-dependent T2* and B0 inhomogeneity blurring and distortion artifacts. To date, parallel imaging has not been widely adapted to animal scanner applications, where advantages for improved performance are sometimes less obvious. We have developed a four channel array intended for 9.4T animal imaging, and evaluated parallel imaging performance in rat brain.

1103. Optimization of Phased Array Coils for Small-Animal MRI at 9.4T Zhangwei Wang1, Martin Tabbert2, Sven Junge2, Roy E. Gordon2, Qing X. Yang1, Michael B. Smith3, Christopher M. Collins1 1The Pennsylvania State University, Hershey, Pennsylvania, USA; 2BRUKER Biospin GmbH, Ettlingen, Germany; 3Novartis Institutes for BioMedical Research, Inc., Boston, Massachusetts, USA

Animal imaging with phased array coils in high field MRI has become increasingly routine. Mice and rats are among the species most often imaged. To increase the SNR in comparison to existing standard quadrature birdcage coils and an existing phased array coil design, we have performed a numerical analysis and comparison of several proposed array geometries loaded with either a rat head or a mouse body considering the axial B1-homogeneity, B1-sensitivity and g-factor distribution.

1104. Design of a Highly Sensitive Solenoid-Based RF-Coil for Small Animal Brain Imaging Hisaaki OCHI1, Satoshi Minoshima1, Donna J. Cross1, Cecil E. Hayes1 1University of Washington, Seattle, Washington, USA

A highly sensitive solenoid-based RF-coil whose sensitivity distribution is suitable for small animal brain imaging has been designed and fabricated. The designed coil was constructed as a combination of solenoid, Counter-Rotating-Current (CRC), and surface coils. We made a current loop at the top of the CRC coil so that the coupling between CRC and surface coils can be canceled out by adjusting the area of the top loop of the CRC coil. The sensitivity of this coil is 30% or more greater than those of QD birdcage coil and multi-channel phased-array coil of the same size.

1105. 20-Channel Mouse Phased-Array Coil for Clinical 3 Tesla MRI Scanner Boris Keil1, Lawrence L. Wald2, Graham C. Wiggins2, Christina Triantafyllou3, Florian M. Meise4, Klaus Jochen Klose1, Johannes T. Heverhagen1 1Philipps University, Marburg, Germany; 2A.A. Martinos Center for Biomedical Imaging, MGH Dept. of Radiology, Harvard Medical School, Charlestown, Massachusetts, USA; 3A.A. Martinos Center at McGovern Institute for Brain Research, MIT, Cambridge, Massachusetts, USA; 4Mainz University School, Germany

The purpose of this study was to develop a dedicated 20-channel phased-array coil for mice imaging using a clinical 3 Tesla MRI system. Especially the challenges for the miniature design and the construction of large numbers phased-array mouse coils is presented. A tiny tubular conductors with an inner and outer diameter of 0.8 mm and 1.2 mm respectively was chosen to build all 20 coil elements. The preamplifiers impedance was transformed to a short at the detuning circuits to provide preamplifier decoupling. The small coil geometry shows good decoupling between elements and performs well in SNR.

1106. Multiple-Mouse MRI with Multiple Arrays of Receive Coils (MARCs) Marc Stephen Ramirez1, James Andrew Bankson1 1The University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA

The efficiency of small-animal MRI studies can be improved by simultaneously scanning multiple animals within a single MRI scanner. To date, this has involved dedicating up to one independent resonator for each animal. In this work, multiple-animal and phased-array technologies were combined to further enhance the imaging efficiency and flexibility of small-animal MRI. Multiple arrays of receive coils (MARCs) were used for accelerated anatomical imaging of two mice in vivo. Reconstructed images from a sensitivity encoding (SENSE) algorithm demonstrate the feasibility of using MARCs to substantially improve the efficiency and reduce the cost of small-animal MRI.

Poster Sessions

206

RF Coil Technology: Non-Array Hall D Wednesday 13:30-15:30

1107. A Novel Planar Design for a 3 T Superconducting “Intrinsically Detuned” MRI Coil Jarek Wosik1, Krzysztof Nesteruk2, Maged R. Kamel1, Flora Ip1, L.-M Xie1, Alexander C. Wright3, Felix W. Wehrli3 1University of Houston, Houston, USA; 2Institute of Physiscs Polish Academy of Sciences, Warsaw, Poland; 3University of Pennsylvania Medical Center, Philadelphia, USA

We report on the design and fabrication of a novel planar superconducting 3.0 T coil for MRI. We have designed and fabricated a high Q coil which is, in principle, intrinsically isolated from the entire body scanner transmit coil. The coil was made out of YBa2Cu3O7-x thin film deposited on a low-loss dielectric substrate. The design consists of two connected double-sided split-gap resonators. Bench measurements as well as numerical simulations of the coils showed more than -40 dB isolation from the transmit coil. In a uniform rf field, this coil should not require special detuning circuitry.

1108. Optimization of SNR Via Cryogenically Cooled Radiofrequency Coils in Hyperpolarized Noble Gas MR Imaging of the Lungs Warren Berger1, 2, Willaim Dominguez – Viqueira1, 2, Juan Parra – Robles1, Giles Santyr1, 2 1J.P. Robarts Research Institute, London, Canada; 2University of Western Ontario, London, Canada

Operating at the low magnetic field strength provided by hyperpolarized noble gases allows significant increases in SNR to be achieved by decreasing the coil’s operating temperature. A receiver coil was constructed and used to image a Xe-129 phantom and rat ventilated with Xe-129. Experiments were performed at room temperature (300K) and at 118K (using liquid nitrogen as a coolant). The gain in SNR by operating at 118 K was measured to be 1.55 and 1.41 in the phantom and rat respectively (corresponding to theory) and are only possible because of the low noise from the sample provided by using Xe-129.

1109. HTS Volume Coil with Improved Imaging Volume S. Y. Chong1, J. G. Liu1, X. G. Zhao2, Keddy Chandran3, S. M. Yeung1, Q. Y. Ma1, E. S. Yang2 1Time Medical System, Hong Kong, Hong Kong; 2University of Hong Kong, Pokfulam, Hong Kong; 3Duke University, USA

In this abstract, a multi-turn 5.5¡¨ large HTS solenoid volume coil & compact cryostat prototype with improved field-of-view (FOV) & high SNR is presented. Although HTS thin-film phased array coil has been demonstrated to increase imaging volume, coupling & isolation between multi-coil, tuning & matching element require complex operation. The result shows the possibility of future large HTS volume coil with compact cryostat for human neuro-imaging with increased FOV & SNR.

1110. Mold Metallization Process for the Batch Fabrication of High-Resolution MRI Solenoidal Micro-Coils Enabling Low Loss Integration of Electronic Devices Mona Julia Katharina Klein1, 2, Takahito Ono3, Masayoshi Esashi4, Jan Gerrit Korvink2 1CSEM, Neuchâtel, Nebraska, Switzerland; 2IMTEK, University of Freiburg, Freiburg, Germany; 3Tohoku University, Sendai, Japan; 4Tohoku University, Tohoku, Japan

The objective of this work is the development of a MEMS-compatible process for the parallel fabrication of solenoidal micro-coils for MR microscopy of biological tissues, e.g. cells. The micro-coil is embedded within two bonded wafers and has a hollow core which enables direct micro-fluidic integration. Signal loss caused by connection to external circuitry may be minimized in this design due to the planar wafer geometry, enabling the use of well-established device bonding techniques. In this paper, we particularly focus on the mold metallization process.

1111. Noise Parameter Extraction in the Design of Low Noise Amplifiers (LNA) for MRI Barbara L. Beck1 1University of Florida, Gainesville, Florida, USA

The first stage of amplification for the very small MRI signal is the Low Noise Amplifier (LNA). An engineering method commonly applied to LNA design in communications utilizes matching components that transform the source impedance to the optimum reflection coefficient of the transistor. Key parameters necessary to perform this method are listed on manufacturer data sheets, but typically for frequencies much higher than those used in MRI. This paper describes a technique to extract these key parameters from simulation, utilizes them to design an optimized LNA, and compares the LNA to one that has been configured for phased array operation.

1112. Implantable MR Probe to Non-Invasively Monitor a Bioartificial Pancreas in Vitro and in Vivo at 11.1T Nelly A. Volland1, Ioannis Constantinidis2, Thomas H. Mareci2, Nicholas E. Simpson2 1University of Florida, Gainesville, Florida, USA; 2University of Florida, Gainesville, USA

Introduction: Development of an implantable inductively-coupled coil system for non-invasive in vivo monitoring of a bioartificial pancreas (tissue engineered construct) at 11.1T is discussed. Methods: System (implantable coil inductively coupled to external coil) was simulated and constructed. Coating and integration of implantable coil with the construct were pursued to test system in vitro. Results: Implantable coil was coated with 1-mm PDMS and cell-free and cell-containing beads were imaged. Sensitivity was shown to be over 10 times higher than sensitivity of previous studies. Conclusions: Implantable inductively coupled coil system was successfully developed and used to image bioartificial pancreas in vitro.

Poster Sessions

207

1113. A Dual-Tuned Quadrature Microstrip Volume Coil for 13C/1H MRI/S at 7T Zhentian Xie1, Duan Xu1, Douglas A. Kelley2, Dan B. Vigneron1, 3, Xiaoliang Zhang1, 3 1UC San Francisco, San Francisco, California , USA; 2GE Healthcare, San Francisco, California , USA; 3UCSF/UC Berkeley Joint Graduate Group in Bioengineering, San Francisco & Berkeley, California , USA

We present an 8-element by 8-element dual-tuned microstrip volume coil for in vivo 13C/1H MRI/S animal studies at 7T. The design strategy of using a mix of half-wavelength resonators and ƒ8¡51/4 wavelength resonators was employed to the 300MHz and 75MHz operating frequencies simultaneously.Preliminary results from a corn oil phantom were acquired using the proposed coil at 7T. The results show that dual-tuned microstrip volume coil is feasible and efficient, provided that sufficient radial separation is maintained between the strip conductor and the ground to provide sufficient coupling between corresponding elements. The proposed design may provide a simple approach to dual-tuned volume coil design for in vivo multinuclear MR at ultrahigh fields.

1114. Dual Tuned Helmholtz Coil for Breast Cancer Imaging Anderson Nnewihe1, 2, Ernesto Staroswiecki1, Neal Bangerter1, Brian Hargreaves1 1Stanford University, Stanford, California , USA

Clinical breast exams using x-ray mammography have limited specificity and sensitivity for detecting breast tumors. Additional imaging modalities such as sodium (23Na) MR have the potential to increase the sensitivity and specificity of breast cancer detection because 23Na MR can reflect the disruption of the membrane Na-K pump associated with cancer. The purpose of this study was to investigate the difference between a dual-tuned Helmholtz coil and a dual-tuned surface coil in providing high SNR and high quality B1 homogeneity for multinuclear imaging as well as perform preliminary breast imaging using the dual-tuned Helmholtz coil.

1115. Circularly Polarized Surface Coil with a Single Port Yoshihisa Soutome1, Hideta Habara1, Yoshitaka Bito1 1Hitachi Ltd., Kokubunji, Japan

A circularly polarized surface coil with a single port has been designed and fabricated. The designed coil was constructed with two series connected loop-coils with an overlap, and its capacitors were designed to have a phase difference of 90o between the two loop currents. A phantom image of the designed coil was very similar to that of a QD surface coil. The SNR profile of the phantom image of the designed coil was identical to that of the QD surface coil. These results indicate that our coil can receive a circularly polarized B1 field without having a QD hybrid like that of the QD surface coil.

1116. Wireless Control of an Implantable Coil System for MRI/S Barbara L. Beck1, Brian S. Letzen1, Rizwan Bashirullah1, Thomas H. Mareci1 1University of Florida, Gainesville, Florida, USA

A proposed solution for monitoring a bioartificial pancreas is a microfabricated wirelessly-controlled multiple-frequency MRI/S coil system. This coil system consists of an external surface coil inductively coupled to an internal monitoring coil. The design incorporates a switchable capacitor/varactor array driven by a microcontroller based on information received wirelessly. The focus of this work was to build a proof-of-concept prototype before developing the entire micro fabricated integrated chip system.

1117. An Efficient Switched Double-Frequency Birdcage Coil for 3He and 1H Imaging Jian-Xiong Wang1, Eddy B. Boskamp2, Giles E. Santyr3, Brian K. Rutt3 1GE Healthcare, London, Canada; 2GE Healthcare, Waukesha, USA; 3University of Western Ontario, London, Canada

This work presented a switched double-frequency birdcage coil aiming for the development of double-frequency clinic body coil. This new technique doesn’t have the coupling problem and it’s easy to be implemented into existing clinic system.

1118. Optimization of Internal MRI Coils Using Ultimate Intrinsic SNR Yigitcan Eryaman1, Yusuf Öner2, Ergin Atalar1 1Bilkent University, Ankara, Turkey; 2Gazi University, Ankara, Turkey

In this work an optimization method for internal MRI coils is explained. Ultimate intrinsic SNR which is the maximum value of the intrinsic SNR that can be obtained by internal MRI coils is used as a measure of performance. As a sample optimization endorectal MRI coils are optimized. The optimized coil is tested in both phantom and patient studies for prostate imaging. Similar methods can be used to optimize different type of internal MRI coils.

RF Systems & Components Hall D Thursday 13:30-15:30

1119. An MRI System with 128 Seamlessly Integrated Receive Channels for Multi-Nuclear Operation Bernd Stoeckel1, Andreas Potthast1, Niels Oesingmann1, Daniel Sodickson2, Ray Lee2, Davide Santoro2, Glyn Johnson2, Thomas Heumann3, Thomas Arnold3, Michael Wullenweber3, Matthias Buettner4 1Siemens Medical Solutions USA, Inc., New York, New York, USA; 2Center for Biomedical Imaging, New York, New York, USA; 3Siemens Medical Solutions, Inc., Erlangen, Germany; 4Astrum IT, Erlangen, Germany

We present the expansion of a commercially available Siemens 3T MR scanner to a system, which enables the online acquisition and reconstruction of images from up to 128 receive channels and which offers multi-nuclear capabilities. The combination of hyperpolarization and a very high number of receive elements is very interesting for two reasons: The initially available SNR is increased and the SNR loss traditionally associated with accelerated parallel imaging may be mitigated or even eliminated. As an example first volunteer lung images with hyperpolarized helium are shown which were acquired with a 128 element receive array at 3He frequency.

Poster Sessions

208

1120. Analog Optical Transmission of 4 MRI Receive Channels with High Dynamic Range Over One Single Optical Fiber Stephan Biber1, Peter Baureis2, Jan Bollenbeck1, Phillip Höcht1, Hubertus Fischer1 1Siemens Medical Solutions, Erlangen, Germany; 2University of Applied Sciences Wuerzburg Schweinfurt, Germany

A new prototype system for analog optical signal transmission between local coil and the receiver is presented in this paper. The system allows to transmit 4 MRI receiver signals on the same optical fiber and implements an optical link with high dynamic range using low cost vertical cavity surface emitting laser diodes (VCSEL). The advantage of an optical transmission concept is the fact that large bundles of copper cables including cable traps for shield wave suppression can become redundant.

1121. Design of Digital Wireless Transmission for 64 Channel Array Using IEEE 802.11n Gary X. Shen1, Juan Wei, Yong Pang 1The University of Hong Kong, Hong Kong, People's Republic of China

This work investigates MRI application using the recent developed technology of WLAN 802.11n (draft) for multiple RF channel EPI. The number of RF channel, signal dynamic range, bandwidth, ADC sampling rate, direct digital synthesizer and digital signal processing control are analyzed and discussed in detail. FDM modulation is used to increase the number of RF channels before ADC. The theoretical analysis and bench test results show that 802.11n can be used for ultra-fast EPI (20 images/s) with 64 RF channels. The MR signal dynamic range could be up to 120 dB.

1122. A Preamplifier for 7T MRI with Extended Dynamic Range and Integrated Cable Trap Klaus Markus Huber1, Martin Hemmerlein1, Stephan Biber1, Ralph Oppelt1, Karsten Wicklow1 1Siemens AG, Erlangen, Germany

The new 7T preamplifier is capable of handling input powers of up to -15.6dBm although consuming less than 250mW of dc power. Its noise figure is as low as 0.6dB. An integrated cable trap suppresses common mode signals and thus makes the design of high channel array coils much easier. The actual size of the amplifier PCB is only about 41mm x 18mm. With a first 3-channel array equipped with the new preamplifiers, outstanding signal to noise ratios have been achieved in a Siemens 7T MRI-system.

1123. Influence of Magnetic Field on Preamplifiers Using GaAs FET Technology Cecilia Possanzini1, Marco Boutelje1 1Philips Medical Systems, Best, Netherlands

In this paper, we show the influence of magnetic field on preamplifiers carrying a GaAs FET (field effect transistor). The S-parameters of the amplifier are measured with magnetic field parallel and perpendicular to the carriers in the FET and compared with data at zero magnetic field. The difference in behaviour of the preamplifier with and without magnetic field can be explained by the occurrence of Hall effect.

1124. Preamp Decoupling - Eigenvalue Solution Approach Victor Taracila1, Keerthi Shet2, Fraser Robb1 1GE Healthcare, Aurora, USA; 2Ohio State University, Columbus, USA

The most modern decoupling method is the preamp decoupling, which consists in bringing a low impedance preamp as close as possible to the coil element and inserting it into a parallel resonance trap which itself is in series with the coils element. This method allows decoupling of the coil elements placed far from each other, which exhibits week coupling and cannot be decoupled by other means. Although there are many interpretation of this techniques based on transmission line theory, we consider that an eigenvalue interpretation is closer to the multiple-degree electrical oscillator, which the MR RF coil represents par excellence.

1125. Optimizing Artwork Cross-Section for Surface RF Coils Victor Taracila1, Fraser Robb1 1GE Healthcare, Aurora, USA

At high frequency the current flows only on the surface of the conductor due to the well known skin effect, the excess of copper will not lower the noise coming from the coil itself. Moreover, very large copper strips will shield the subject (object) under study from transmit RF field introducing significant B1 field distortion. This problem can be solved for one dimension and even two dimensions for a rectangular cross-section using complicate mathematical methods. Presented method is simpler and can easily be applied to any cross section of the copper strip.

1126. Can Inkjet Printing Produce MRI Coils? Patrick J. Smith1, Dario Mager1, Ute Loeffelmann1, Jan G. Korvink1 1University of Freiburg, Freiburg, Germany

To the knowledge of the authors, inkjet printing has not yet been used to produce MRI RF transmit and receive coils, possibly because of the variability of the fabrication technology, and the lack of low resistivity metal-containing inks. In this paper, we discuss the questions and responses facing an inkjet-based processing route for MRI coils, and report on the experimental steps that have been undertaken to demonstrate the veracity of the answers.

1127. Ultra Low Susceptibility PIN Diodes for High Field Ronald D. Watkins1, William Doherty2, Pavel Voskoboynik 1Stanford Medical School, stanford, California , USA; 2MicroSemi Corp, Lowell, USA

Authors here have developed and demonstrated greatly improved RFPIN Diode components for reducingsusceptibility artifacts at high field

1128. Spurious Proton Signal from Phased Array Coil Materials- How Much Proton Signal is Too Much? Victor Taracila1, Fraser Robb1 1GE Healthcare, Aurora, USA

A receive RF coils contains material like Kapton™ tape, Delrin™ rods, Polycarbonate, Nylon etc., which do contain a certain amount of proton signal. The ideal situation would be to eliminate completely all Hydrogen from all building components. However, it could be costly and sometimes unnecessary if the amount and relaxation times T1 and T2 are correlated with existing gradient slew rates, RF pulse width and the very matter we intend to image – living organisms.

Poster Sessions

209

1129. MRI Dynamic Range: Theory and Measurement Refaat E. Gabr1, Michael Schar1, 2, Arthur D. Edelstein3, Paul A. Bottomley1, William A. Edelstein1 1Johns Hopkins University, Baltimore, Maryland, USA; 2Philips Medical Systems, Cleveland, Ohio, USA; 3University of California, Berkeley, Berkeley, California , USA

We have undertaken MRI dynamic range (DR) measurements in order to determine compatibility of MR multicoil images with fiber optic signal transmission. Our results indicate that such links should be viable at 3T and possibly higher.

Transceiver & Control Systems Hall D Monday 14:00-16:00

1130. A Simple Vector Modulator Approach to Phase and Amplitude Control for B1 Shimming Ke Feng1, Xiaojun Chen1, William A. Grissom2, Douglas C. Noll2, Mary Preston McDougall1, Steven M. Wright1 1Texas A&M University, College Station, Texas, USA; 2University of Michigan, Ann Arbor, Michigan, USA

B1 shimming is an alternative approach to Transmit SENSE as a method of compensating for full-wave effects at high fields. In order to perform B1 shimming, independent amplitude and phase control of the overall RF pulse is required for each element or input port of a multi-port coil. Digital attenuators and phase shifters with sufficient resolution are quite expensive. This paper presents an inexpensive alternative which combines a vector modulator with digital potentiometers to realize a simple and scalable system to control an array for B1 shimming. In addition, by replacing the digital potentiometers with more expensive fast digital-to-analog boards, the system is capable of full modulation for transmit SENSE.

1131. RF Switching Matrix Enables 128 Channel Architecture and Dynamic Element-To-Receiver Routing Yuan Ma1, Jennifer A. Black1, Vanish K. Dabra1, William Peterson1 1GE Healthcare, Waukesha, Wisconsin, USA

A high linearity, low-noise radio frequency switching matrix has been created to enable 128-channel architecture and dynamic element-to-receiver routing. This was accomplished using RF simulation tools, careful component selection, and programmable intelligence control.

1132. A Wire-Free, Radio-Frequency, Shielded Projection Window for MRI Suites David Ian Hoult1, Patricia Gervai1, Uta Sboto-Frankenstein1 1National Research Council Institute for Biodiagnostics, Winnipeg, Canada

The investigation by fMRI of neural mechanisms associated with visual stimuli is now relatively common. However, the absence of high-quality, wire-free projection windows in MRI suites, particularly at the back of the magnet, often forces investigators to place video projectors inside the shielded room. This poses potential hazards including the risk of projector malfunction and over-heating. Thus a salt-solution window with good optical properties is proposed as a solution to this problem.

1133. Reconfiguration of a “standard” Biospec Spectrometer for Simultaneous 2-Channel Acquisitions: Application for Mouse Brain MRI and MRS Adrian Rengle1, Hélène Ratiney1, Adriana Bucur1, Sophie Cavassila1, Olivier Beuf1 1INSA-Lyon, Université Lyon 1, Villeurbanne, France

In the field of small animal imaging, the interest for phased-array coil imaging is growing but high field MR experimental systems with multiple receiver channels are still rare and the upgrade of existing systems is relatively expensive. In this work, a standard 4.7T Bruker Biospec Avance II spectrometer was modified to allow simultaneous two-channel acquisitions. Modifications were validated on imaging and spectroscopy on metabolite solution phantom as well as on mice brain using a home-made two-channel array coil. Compared to a single-channel surface coil, the mean SNR was improved by about 20%. Modifications realized for proton multiple-channel acquisitions could also be applied for any X-nucleus. Compared to quadrature detection coils, two-channel coils offer the ability to use parallel acquisitions techniques.

1134. Dynamic Downconversion Module for MR Applications Jennifer A. Black1, Yuan Ma1, Vanish K. Dabra1 1GE Healthcare, Waukesha, Wisconsin, USA

A small down-conversion module was developed for 1.5T and 3T MR imaging subsystems to allow for dynamic amplification and increased system modularity. This module places the frequency of the MR signal within the frequency range of an analog-to-digital receiver board. Noise figure, linearity, and amplification re optimized in this 1-inch by 2.5-inch module, which can be used for “mix-on-coil” surface coil development or within large switching matrices.

1135. Efficient Tune and Match with Multiple Transmit Coils John P. Strupp1, Edward J. Auerbach1, Ark Gozubuyuk1, Gregor Adriany1, Kamil Ugurbil1, Pierre Francois Van de Moortele1 1University of Minnesota, Minneapolis, Minnesota, USA

An RF switch box with a multi-channel cable assembly was engineered to facilitate the efficient tune and matching of multi-channel transmit coils as used in ultra high field applications. A particular challenge was finding components that were either made of non-magnetic materials or that could be easily modified to be so. Typically the system can decreases coil setup time from tens of minutes to just minutes when compared to the traditional method using just an RF sweeper probe tuner and a handful of 50 ohm terminators.

Poster Sessions

210

1136. Direct MRI Detection at 3T and 9.4 T Using 16-Bit High-Speed Digital Receiver Andrzej Jesmanowicz1, James S. Hyde1 1Medical College of Wisconsin, Milwaukee, Wisconsin, USA

A new 16-bit digital receiver with three LTC2208 A/D converters sampling at 100 MHz at 3T and 120 MHz at 9.4T was evaluated for off-line real-time image acquisition. Tested were: the dynamic range improvement, the maximum usable MRI frequency range and the ability to abandon a reference frequency shift between slice selection pulse and readout time. At 35T (1500 MHz) the dynamic range increase together with drop of sensitivity makes the dynamic range of this converter equal to the old, 2 MSPS 16-bit A/D converters used in commercial scanners.

1137. Influence of RF Synthesizer Phase Noise on MR Imaging Stability Martin Nisznansky1, Joerg Stapf1, Markus Vester1, Philipp Hoecht1, Jan Bollenbeck1, Wilfried Schnell1 1Siemens AG Medical Solutions, Erlangen, Germany

phase noise, RF synthesizer, EPI, fMRI, image-to-image stability, SNR

1138. Ultra Low Noise Preamplifier for Transmit/receive Coils: Upgrading MR Systems Without Further Modifications of the Hardware Johannes Sell1, Florian Fidler2, Toni Hippmann3, Michael Ledwig2, Peter Michael Jakob1, 2 1University of Wuerzburg, Wuerzburg, Germany; 2Research Center Magnetic-Resonance-Bavaria, Wuerzburg, Germany; 3FH Wuerzburg-Schweinfurt, Germany

A concept for a noise matched low noise preamplifier with integrated transmit bypass is proposed. It has a single wire connection and can be integrated into many existing MR systems without the need of additional wiring. Successful tuning/matching of transmit/receive coils has been demonstrated. The design is adjustable for a wide frequency range with minor changes.

1139. A 500 W, Broadband, Non-Magnetic RF MOSFET Amplifier for MRI Use David Ian Hoult1, Glen Kolansky1 1National Research Council Institute for Biodiagnostics, Winnipeg, Canada

Initial experiences in building a push-pull, 500W, broadband, non-magnetic MOSFET amplifier are described. For use with Cartesian feedback, the amplifier can be placed at the magnet bore entrance. Strategies for dissipating 1 kW of heat are described and cold-plate liquid cooling is advocated. Direct Q-factor measurements confirm that the MOSFET dynamic output resistance alone (without feedback) is not high enough to provide good current blocking in coupled phased-array coils. A 4:1 Guanella toroidal transformer and a pancake autotransformer are advocated to provide broadband power performance while coping with the MOSFETs’ large drain-source capacitance.

1140. Scalable Low-Profile Linear Amplifier Module for Parallel Transmission in MRI Xiaojun Chen1, Ke Feng1, Mary Preston McDougall1, Steven M. Wright1 1Texas A&M University, College Station, Texas, USA

Parallel transmission has been suggested as a method to improve RF excitation, in paticular, multi-dimensional and spatially selective excitation at high fields. Both B1 shimming and Transmit SENSE require multiple channels of RF amplifiers, though at lower power levels than may be required with single channels. Particularly as the number of channels increases, the power level requirement per channel drops to values that lend themselves to modular compact construction. This abstract reports our progress in developing a low-profile, linear, high-gain amplifier with a high degree of noise blanking. The module reported here generates 45 watts per channel and offers high efficiency, high linearity, low cost and plug-in modality which make it attractive for scalable parallel transmission systems. It could also serve as a driver stage for whole body Transmit SENSE. This work is designated to be used with a vector modulator designed in-house.

1141. On the Operation of Bluetooth Devices Inside the MR Faraday Cage General Leung1, Garry Liu1, Kevan J T Anderson1 1Sunnybrook Health Sciences Centre, Toronto, Canada

Bluetooth technology provides an attractive means of communicating with devices confined within the Faraday cage of the MR magnet. Unfortunately, the Faraday cage significantly attenuates a Bluetooth signal such that communication becomes unreliable. To circumvent this, a USB Bluetooth transceiver can be placed within the waveguide enabling broadcasting of the Bluetooth signal inside the Faraday shield. The purpose of this study was to quantify the communication reliability of Bluetooth devices compared with image noise contamination by compromising the waveguide.

1142. A Versatile USB-Based Control System for Instrumentation in a Magnetic Field Derek Foreman1, Glen Kolansky1, David Ian Hoult1 1National Research Council Institute for Biodiagnostics, Winnipeg, Canada

Massively-parallel digital control, from outside the MR suite, of instrumentation (e.g. multiple Cartesian feedback transceivers) in a strong magnetic field close to an MR magnet creates problems of complexity, cross-talk, interference and speed reduction. To solve these problems, a low-cost, 40 MByte per second USB-based, bi-directional, non-magnetic serial link requiring only 2 coaxial or fibre-optic cables has been implemented, together with a custom programming language that describes the computer-instrument interface hardware.

1143. Quantitative Mechanical Stimulator for FMRI and MicroPET Studies Wei-Chieh Wong1, Yen-Yu Shih1, 2, Yun-Chen Chiang1, 2, Chien-Hsiang Huang1, 2, Chen Chang2, Fu-Shan Jaw1 1Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan; 2Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan

The present study developed a fully MR-compatible, computer-controlled, pneumatic stimulator to deliver quantitative tactile stimulation. Mechanical stimulation of the hindpaw of rat significantly increased BOLD signal intensity in the primary somatosensory cortex of the hindlimb region (S1HL). The results validated the feasibility of this stimulator and were coincident with the microPET experiment.

Poster Sessions

211

1144. A Simple, Robust, Low-Cost Respiratory Trigger Unit for Imaging Rodents in Whole Body Clinical Scanners Karl-Heinz Herrmann1, Enrico Wagner1, Andreas Deistung1, Ines Krumbein1, Jürgen R. Reichenbach1 1Friedrich-Schiller-University, Jena, Germany

Animal experiments are increasingly conducted on clinical MR systems. For rodents, however, the default trigger systems of whole-body scanners are usually not sensitive enough to detect the tiny motions. Therefore, an MRI-compatible low-cost solution for triggering the respiratory motion of small rodents was constructed. An optical motion detector was used in conjunction with a robust analog electronic circuit, which converts the original optical into an electrical signal, compensates slow drifts and offsets and finally converts the motion signal into a TTL trigger for the clinical whole body MRI scanner. The trigger was successfully applied in mouse experiments.

1145. An Ultra-Low Field Imaging Instrument and Analysis of Its SNR and Scaling Properties Byeong-Ho Eom1, Mark Steven Cohen2, Inseob Hahn1, Konstantin I. Penanen1 1California Institute of Technology, Pasadena, California , USA; 2University of California, Los Angeles, Los Angeles, California , USA

We present here a description of a novel approach to MRI operating at less than the earth's field and show that the SNR potential is comparable to that of traditional high field instruments.

1146. Development of a Local RF Shielding Method for Whole Hand Imaging Shinya Handa1, Kazuya Taniguchi1, Katsumi Kose1, Tomoyuki Haishi2 1University of Tsukuba, Tsukuba, Japan; 2MRTechonology Inc., Tsukuba, Japan

A local RF shielding method has been developed using a conducting plate and a LC balun circuit for a whole hand MRI system. Using an artificial external noise, the RF shielding performance was quantitatively evaluated. The result demonstrated that the whole hand imaging could be performed without a shielded room.

1147. Intuitive Interface for MR Scan Plane Prescription Rahul Sarkar1, 2, Chrishnika de Almeida1, Noureen Syed1, Sheliza Jamal1, Jeff Orchard1 1University of Waterloo, Waterloo, Canada; 2Sunnybrook Research Institute, Toronto, Canada

We present a novel 3D user interface model for scan plane prescription in MRI. The interface consists of a hand-held panel that is manipulated by the user in free space, resulting in analogous real-time prescription of the scan plane in the reference volume. By providing 3D input directly, the interface aims to reduce the cognitive effort associated with conventional interfaces that use the mouse for scan plane prescription. We describe a basic implementation of this model and the results of a user study that compared the effectiveness of the panel interface with a traditional mouse-based interface.

MR Systems, Magnets, Gradients, Shims Hall D Tuesday 13:30-15:30

1148. Self-Shielded Open Superconducting Magnet Design Franco Bertora1, Elisa Molinari1, Andrea Viale1 1Italian Institute of Technology, Genova, Italy

Permanent magnet design for MRI has always followed lines that are forcedly different from those employed in designs using superconductors yet, from a basic point of view, the physical principles are the same and a block of permanently magnetized material can be considered as the epitome of ambient temperature superconductivity. When confronted with the problem of designing an open scanner for functional imaging the techniques employed in designing permanent magnets can advantageously be applied to superconducting windings, particularly now that emerging materials such as MgBr2 afford relative ease in the construction of cryogen-free devices.

1149. An Optimised Elliptical Magnet for Deep Surface NMR Imaging Manola Ciarrocchi1, Angelo Galante1, Vincenzo Di Miccoli2, Marcello Alecci1, Antonello Sotgiu1 1University of L'Aquila, L'Aquila, Italy; 2Itel Telecomunicazioni, Ruvo di Puglia, Italy

Unilateral NMR allows positioning of the sample on the surface of a portable measuring device and this technique has been used for several MRS/MRI applications. However, the open magnet geometry produces a magnetic field with high inhomogeneity, giving rise to reduced relaxation time T2*. MRI applications require a good field homogeneity and increased penetration depth. Unfortunately, most of the unilateral devices present in the literature do not satisfy both these requirements. Here we report the design of a novel elliptical unilateral magnet with improved field homogeneity and penetration along one direction.

1150. Shimming a 0.2 T Permanent Imaging Magnet with Small NdFeB Magnets David Ian Hoult1, Qunli Deng2, Boguslaw Tomanek2 1National Research Council Institute for Biodiagnostics, Winnipeg, Canada; 2National Research Council Institute for Biodiagnostics, Calgary, Canada

Field shimming (20 ppm over a 30 cm diameter sphere) with small NdFeB magnets on the pole faces of an inexpensive, 0.2 T, permanent imaging magnet is described. Problems overcome included: 950 ppm starting inhomogeneity; drift during field plotting; magnetic moment inconsistency; unknown, induced local pole-face magnetisation; change of magnetisation with magnet inversion, and insufficient convergence of spherical harmonic amplitude with order for magnets close to pole face centres. Keys to success were the modelling of pole face magnetisation by a perpendicular line of magnets and the use of constrained linear programming to maximise the number of shimming magnets.

Poster Sessions

212

1151. Characterization of MRI Properties of Human Body Tissues at MicroTesla Magnetic Fields Byeong-Ho Eom1, Mark Steven Cohen2, Inseob Hahn1, Konstantin I. Penanen1 1California Institute of Technology, Pasadena, California , USA; 2University of California, Los Angeles, Los Angeles, California , USA

Using an imager operating at 170 microTesla we studied the in vivo relaxation characteristics of human tissue and discuss the contrast range and instrument optimizations necessary to provide quality low field imaging

1152. Towards Routine Field Monitoring for MRI: A Transmit/receive System Based on Shielded NMR Probes Christoph Barmet1, Nicola De Zanche2, Bertram Wilm2, Klaas P. Pruessmann2 1University and ETH Zürich, Zürich, Switzerland; 2University and ETH Zürich, Switzerland

Magnetic field monitoring with NMR probes is a promising approach but suffers from practical limitations when performed with receive-only probes, relying on external RF excitation. This contribution describes the implementation of a transmit/receive monitoring system, relying on autonomous probeheads equipped with individual RF excitation and RF shielding against MR contamination from the actual imaging experiment. The newly designed probes are found to offer sufficient sensitivity and RF shielding, enabling straightforward monitoring of MRI procedures, as exemplified by initial phantom scans.

1153. Residual Magnetism in MR Suites After Field Rampdown of Superconducting Magnets Steffen Sammet1, Francisco Aguila1, Regina Maria Koch1, Michael Vincent Knopp1 1The Ohio State University, Columbus, USA

The rampdown of two superconducting clinical magnets, one at 8T and one at 0.7T, was used to evaluate residual magnetization within the MRI suite environments prior, during and after field-rampdown. A controlled rampdown of even an ultrahigh field MR system does not lead to retained magnetic contamination, while forced quenched rampdown of a mid-field system revealed temporary negative remanence.

1154. Comparison of Magnetic Field Monitoring with Alternative K-Space Trajectory Measurement Methods Silke Maria Lechner1, 2, Adam B. Kerr3, Pekka T. Sipilä1, 2, Rolf F. Schulte1, Dirk Lange1, Florian Wiesinger1 1GE Global Research, Munich, Germany; 2Technical University Munich, Munich, Germany; 3Stanford University, Stanford, USA

Magnetic Field Monitoring (MFM) has been used as k-space trajectory measurement technique, whereupon the calibrated information is used in image reconstruction and result in reduced imaging artifacts like blurring and geometric distortions. This work presents a comparison of MFM with an alternative measurement method commonly used in MR. It is shown that higher image quality and less blurring artifacts are achieved using MFM. The comparison is evaluated in multi shot spiral out and echo-planar imaging sequences and demonstrated to substantially reduce artifacts in both, spiral and EPI. Image entropy is used as a quantitative quality metric.

1155. Gradient Linear System Modeling Using Gradient Characterization Joseph Y. Cheng1, Borjan Aleksandar Gagoski1, Divya S. Bolar1, Christina Triantafyllou2, 3, Michael Hamm4, Gunnar Krueger5, Elfar Adalsteinsson1 1MIT, Cambridge, Massachusetts, USA; 2Athinoula A. Martinos Imaging Center, McGovern Institute for Brain Research, MIT, Cambridge, Massachusetts, USA; 3Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, MGH, Charlestown, Massachusetts, USA; 4Siemens Medical Solutions, Charlestown, Massachusetts, USA; 5Siemens Medical Solutions, Lausanne, Switzerland

The gradient system is modeled here as a linear time-invariant system, H(f), through a frequency-domain analysis. The model is obtained using a recent gradient characterization technique that combines two previous methods to optimize flexibility, speed, and accuracy. The obtained H(f) generalizes the gradient system to allow for a fast and accurate distortion prediction. As a result, the model will contribute to a robust correction method.

1156. Compensation of Eddy Current by an R-L-C Circuit Model of the Gradient System Sang Heom Cho1, Pan Ki Kim1, Jong Woo Lim2, Su Yeol Jeon1, Chang Beom Ahn 3 1Kwangwoon University, Seoul, Republic of Korea, 2ISOL Technology

The k-space trajectory is important in the design of spiral pulse sequence as well as in the reconstruction of the image. The real trajectory is, however, usually deviated from the theoretical trajectory obtained from the gradient waveforms due to the eddy currents and non-ideal performances of the gradient systems such as finite bandwidth and slew rate. Such deviations inevitably result in distortions in the reconstructed image. In this paper, we derived an R-L-C circuit model to estimate the real k-space trajectory, by which a significant improvement of reconstruction was achieved at 3 Tesla MRI system.

1157. Reduction of MRI Scanner Acoustic Noise Using a Micro-Perforated Panel Absorber Michael Li1, Chris K. Mechefske1 1Queen's University, Kingston, Canada

The trend toward higher field strength is worsening the noise problem in MRI. A Boundary Element Method simulation showed that a micro-perforated panel acoustic absorber can significantly reduce MRI noise in the scanner bore. The impedance function of the absorber was used to predict the sound attenuation effect. However, the absorption coefficient functions calculated according to Maa’s theory do not reflect the absorbing effect of a micro-perforated panel absorber in a cylindrical duct such as an MRI scanner bore because the expression of impedance of air gap is based on the assumption of plane waves.

1158. Vibration Induced Eddy Current and Its Effect on Image Quality for MRI System Longzhi Jiang1, Tim Havens2, William Einziger2 1GE Healthcare, Florence , USA; 2GE Healthcare, Florence, USA

During normal operation, MRI systems experience vibration from different external sources, e.g. refrigeration unit, environmental ground vibration and gradient coil pulse. Moving conductors within the MRI system will generate eddy currents, disturbing the homogenous magnetic field and affecting image quality (so called “ghosting”). In this study, vibration induced magnetic field fluctuation was investigated on a system with a single degree of freedom to illustrate the behavior. The methodology was then extended to a 3 dimensional MRI system by using FEM/BEM. Experimentally simulated results are presented, showing general agreement between experimental results and simulation for the 1.5T MRI system.

Poster Sessions

213

1159. Control of Gradient Coil Natural Frequency Using a Topology Optimization Technique Sun Yong Kim1, Il Yong Kim1, Chris K. Mechefske1, Doo Ho Lee2 1Queen's University, Kingston, Canada; 2Dong-eui University, Busan, Republic of Korea

By controlling the natural frequency of the single-winging gradient coil, it is possible to reduce vibration resonant frequency amplitude. The overall noise and vibration of the structure can also be reduced. Viscoelastic damping material is widely used to suppress noise and vibration in industry due to its easy application and economic advantage. A full treatment of the damping material on the gradient coil does not give a maximum damping effect for the structure. The optimum location, thickness and shape of the damping sheets are being determined using topology optimization. This work aims to minimize the level of noise and vibration of the structure.

1160. Phantom Correction of Human Images for Spatial Scaling Errors Jeff Gunter1, Matt Bernstein2, Bret J. Borowski2, Paula J. Britson1, Chadwick P. Ward2, Clifford R. Jack, Jr. 2 1Mayo Clinic and Foundation, Rochester, Minnesota, USA; 2Mayo Clinic, Rochester, Minnesota, USA

An investigation of the applicability of phantom-derived scanner scaling estimates close-in time human images is presented. Phantom correction reduces human image scaling variability within and across scanners.

1161. Frequency Spectrum of Partial Discharge Events Derek A. Seeber1, Tony M. Linz2, Bruce D. Collick2, Anthony Mantone1 1GE Healthcare, Florence, South Carolina, USA; 2GE Healthcare, Waukesha, Wisconsin, USA

Each gradient coil, inner and outer, consists of three layers corresponding to the X, Y, and Z-axes of the gradient coil. The inner and outer gradient coils each have two radial spaces between adjacent axes. The radial spacing between adjacent axes is required to reduce the occurrence of “white pixels” and voltage breakdown during an MRI scan. If the “white pixel” performance of the gradient coil can be increased, the radial space savings can be incorporated into an increased patient bore, reduced magnet expenditure, or increased gradient slew rates with higher applied gradient voltages.

1162. Modal Sound Radiation from Finite Cylindrical Shells Tian Ran Lin1, Peter O'Shea1, Chris K. Mechefske2 1Queensland University of Technology, Brisbane, Australia; 2Queen's University, Kingston, Canada

Modal radiation efficiencies of two fundamental circumferential modes of several different length finite cylindrical shells are studied in this paper. Modal radiation efficiencies of the finite cylinders are found to asymptotically approach those of the corresponding infinite cylindrical shell when the length of the cylinder divided by the circumference modal index (n>1) is more than twice that of the acoustic wavelength. There are two radiation peaks in the modal radiation efficiency attributed to the ring and critical frequencies of the finite cylinder.

1163. Initial Realisation of a Multichannel, Non-Linear PatLoc Gradient Coil Anna Masako Welz1, Maxim Zaitsev1, Heinrich Lehr2, Gerrit Schultz1, Zhenyu Liu3, Feng Jia3, Hans Post2, Jan Korvink3, Jürgen Hennig1 1University Hospital Freiburg, Freiburg, Germany; 2Bruker BioSpin MRI GmbH, Ettlingen, Germany; 3University Freiburg, Freiburg, Germany

This abstracts presents the initial realisation of image encoding with a multichannel, non-linear PatLoc (parallel imaging in localized gradients) gradient coil and first reconstructed images. Imaging in non-linear, non-bijective magnetic fields has the advantage of faster imaging, or higher resolution especially at the periphery. To conserve some image reconstruction properties, in plane orthogonal gradients were chosen, in radial and circumferential direction. A cylindrical concept was developed for later use as a head gradient set. The first demonstrator is designed for use in an animal system for easier access to the hardware.

1164. Parametrical Optimization of a PatLoc Gradient Coil zhenyu Liu1, Feng Jia1, Maxim Zaitsev2, Anna Welz2, Gerrit Schultz2, Jan G. Korvink1, Juergen Hennig2 1Dept. of Microsystems Engineering, Laboratory for Simulation, University Freiburg, Freiburg, Germany; 2Dept. of Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Freiburg, Germany

A simple iterative optimization method, instead of the commonly used target field method, is presented to design PatLoc gradient coil. The optimization procedure includes the calculation of the magnetic value using the Biot-Savart method, the determination of the optimal number of conductor should be used, and the corresponding space positions. In order to use the continuous optimization method to optimize the discrete conductors, the continuation method is used to transform the integral design variable to bounded continuous design variable. The optimal solution still keeps the discrete conductor distribution so that the optimized gradient coil can be fabricated without further post-processing.

1165. Shoulder-Slotted Insertable Gradient and Shim Coil Set Michael Poole1, Dan Green2, Richard Bowtell1 1University of Nottingham, Nottigham, UK; 2Magnex Scientific Ltd., Yarnton, UK

Insert gradient and shim coils designed specifically for head imaging can be made smaller and therefore of lower inductance and resistance as well as capable of producing more intense magnetic fields. Here, an Inverse Boundary Element Method was used to design a cylindrical, shoulder-slotted 3-axis head gradient coil set, also containing 0th and 2nd order shim coils, The shim coils were designed to have low-inductance so as to allow the fast current switching required by dynamic shim updating. The gradient and shim coil set has been constructed and tested at 3T in imaging experiments.

Poster Sessions

214

1166. Dynamic Shimming at 7 Tesla Saikat Sengupta1, Yansong Zhao2, David Foxall2, Piotr Starewicz3, Adam Anderson1, John Gore1, Malcom Avison1 1Vanderbilt University Institute of Imaging Science, Nashville, USA; 2Philips Medical Systems, Inc, USA; 3Resonance Research, Inc, Billerica, USA

We have implemented dynamic shimming on Philips Achieva human 7Tesla system A Real Time Shim System, RTS, (Resonance Research Inc, MA, USA), was used for higher order shim control. Shim corrections were calculated from preacquired fieldmaps. The 1st order corrections were loaded slice wise through the gradient controls and the 2nd order shims were loaded from the RTS system. The static field standard deviations across the brain in all slices were significantly lower with dynamic shimming than with global shimming. This improvement in B0 homogeneity was reflected in reduced signal drop-out and lower image distortion.

1167. Power Versus Inductance: Finite Length Shim Coil Design for High-Field MRI Parisa Jamali1, Blaine A. Chronik1 1University of Western Ontario, London, Canada

We designed high power, high order shim sets with constrained length using two methods: the minimum inductance method and the minimum power method. While the minimum inductance method gave higher inductive merit and the minimum power method gave higher resistive merit, the percent difference in merits between the two methods was less than six percent. This indicates that we can use the minimum power method for the design of our shim axes.

1168. Local Uni-Planar Gradient Array Design Using Conformal Mapping and Simulated Annealing Sung M. Moon1, D.N. Ghosh Roy1, K. Craig Goodrich1, J. Rock Hadley1, Dennis L. Parker1 1University of Utah, Salt Lake City, Utah, USA

Many imaging problems, such as breast lesion characterization, can require high spatial and temporal resolution. The improved gradient performance required to achieve high spatial and temporal resolution may be achieved by specially designed local gradient coils such as planar gradient inserts. We present simple and rapid method for design of flat gradient inserts to produce a high strength gradient field and a reasonably uniform imaging region. The planar gradient set is to be placed inside of the imaging bore of the magnet (within the body gradients). For cylindrical gradients, a one dimensional stream function (SF) is used to specify currents on the cylinder surface. For planar gradients, however, this becomes a more complicated two dimensional problem.

1169. Effect of Active Shielding on Zonal Shim Coils for a 31cm Bore 9.4T MR System Dustin Wesley Haw1, Blaine Alexander Chronik1 1University of Western Ontario, London, Canada

MRI and in-vivo spectroscopy in preclinical applications at very high field (9.4T and above) require improved shimming capabilities. Our goal is to develop and optimize high strength, dynamic shim systems for our 31cm bore 9.4T MR system. It is clear that dynamic shim systems will need to be actively shielded; however, we are interested in investigating how shim performance of shielded shim coils changes as a function of shim order. In all cases the efficiency of unshielded shim coils is better than that of shielded shim coils, as expected. However, the difference decreases considerably with increasing shim order.

1170. MR Imaging Capability of a Field-Cycled MRI/PET Scanner Kyle Michael Gilbert1, Timothy James Scholl1, Blaine Alexander Chronik1 1The University of Western Ontario, London, Canada

Field-cycled MRI employs two separate, actively controlled resistive magnets to polarize a sample and to provide the magnetic field environment under which data is acquired. A field-cycled MRI system was constructed with a central gap to allow for the inclusion of a PET ring. The SNR and magnetic field homogeneity of the field-cycled MRI system were sacrificed to create a dual-modality scanner. To compensate, a low-pass birdcage coil and a higher order shim set were built, allowing for the acquisition of quality MR images.

1171. From Static to Dynamic: Construction of a B0 Insert for Field-Cycled Contrast in a Clinical MR Scanner Jamu K. Alford1, Timothy J. Scholl1, William B. Handler1, Brian K. Rutt2, Blaine A. Chronik1 1The University of Western Ontario, London, Canada; 2Robarts Research Institute, London, Canada

To allow field-cycled contrasts in superconducting MR scanners, we have built an actively shielded B0 insert. This insert produces significant magnetic field shifts in the imaging region of clinical MR systems without destabilizing their main field or producing eddy-currents. The insert coil is composed of a powerful primary coil responsible for the B0 field shift and a precisely designed, counter wound, outer shield designed to reduce the insert's fringe field. Design, construction and testing of this unique insert are discussed.

1172. Towards Simultaneous PET and Field-Cycled MRI: Active Shielding for PMT Detectors Dustin Wesley Haw1, Blaine Alexander Chronik1 1University of Western Ontario, London, Canada

Combined PET and MR scanners are currently under development as a means to obtain specific functional data from PET, registered both temporally and spatially with high-resolution anatomical images from MRI. One approach is to use PET and field-cycled MRI (FCMRI), which uses two separate and dynamically controlled magnets for the polarization and readout phases of MRI, in an interleaved manner. Actively shielded polarizing magnets reduce the magnetic field over the region in which the PMTs would be placed, and allow for extended PET operation during the polarizing phase of FCMRI.

1173. Quantitative Signal and Phase Analysis of a Field-Cycled MRI Scanner Kyle Michael Gilbert1, Timothy James Scholl1, Jamu Krishna Alford1, Blaine Alexander Chronik1 1The University of Western Ontario, London, Canada

Field-cycled MRI employs two actively controlled electromagnets to polarize a sample and to provide the magnetic field environment during data acquisition. Instabilities in the readout magnet can cause phase errors and image artifacts in the phase-encode direction. The stability of the readout magnet was quantitatively evaluated, along with the expected signal trends. Images were acquired with no visible phase-encode artifacts.

Poster Sessions

215

1174. Preliminary Results of CdTe Detector Capabilities Toward MRI-SPECT Takao Goto1, Yuji Iwadate1, Yoshio Mito2, Tetsuji Tsukamoto1 1GE Yokogawa Medical Systems, Hino-shi, Japan; 2Acrorad co. ltd, Uruma-shi, Japan

Recently there have been new interests in MR Hybrid Systems such as MR-PET and MR-SPECT. CdTe detector has valuable potentials as a new radiation detector and does not need Photo Multiplier. We investigated the interference of MR and CdTe detector toward MR-SPECT realization measuring Enegry Spectra changes, imaging Co-57 point source and scanned MR phantom with Tungsten laminated collimator in both 1.5T and 3T magnetic field. As a result, it is demonstrated that there was no significant effect in working CdTe detector in both 1.5T and 3T and found collimator effect could be avoided to scan specified imaging plane.

1175. Design and Fabrication of a Magnetic Resonance Stage Microscope Andrey V. Demyanenko1, Julian Michael Tyszka1 1California Institute of Technology, Pasadena, California , USA

A uniplanar geometry analogous to an inverted stage optical microscope is proposed for high resolution MR imaging which addresses many of the limitations of conventional volume gradient and RF coil designs, particularly restrictions on medium volume and physical access when imaging small organisms such as developing embryos or thin tissue explants. The stage microscope geometry provides unhindered access to the sample from above, encouraging the future integration of optical imaging equipment with MR microscopy.

1176. Multiple Mouse Imaging of 16 Live Mice Jonathan Eric Bishop1, Shoshana Spring1, Jun Dazai1, Brige Paul Chugh1, Sharon Portnoy1, Steven Suddarth, G Ronald Morris, R Mark Henkelman1 1Hospital for Sick Children, Toronto, Canada

Preliminary results for fully parallel imaging of 16 live mice are presented. The technique scales well and provides a significant increase in throughput compared to single mouse imaging.

1177. Development of a Compact Whole Hand MRI System for Diagnosis of Rheumatoid Arthritis Using a 0.3 T Permanent Magnet Shinya Handa1, Katsumi Kose1, Tomoyuki Haishi2 1University of Tsukuba, Tsukuba, Japan; 2MRTechonology Inc., Tsukuba, Japan

A compact whole hand MRI system for diagnosis of rheumatoid arthritis (RA) was developed using a 0.3 T permanent magnet and a locally shielded RF probe. The total system was installed in a 1.5 m × 2.0 m open space. Because the T1 weighted 3D images showed 1.6 times SNR advantage over those obtained with a 0.21 T permanent magnet previously reported, we concluded that our new system can be used for evaluation RA with reduced examination time or higher spatial resolution in the same examination time.

Computational Electromagnetics Hall D Wednesday 13:30-15:30

1178. 3D MRI-Based Electric Properties Tomographie Reconstruction Using Volume Currents in the Method of Moments Christian Findeklee1, Ulrich Katscher1 1Philips Research Europe, Hamburg, Germany

The distribution of the electric conductivity σ; and permittivity ε; of human tissue can be used as diagnostic parameter and for a prediction of local SAR during MR measurements. Electric Properties Tomography (EPT) offers a way to determine these electric properties via MRI. In this work, equivalent volume currents in the Method of Moments were used for the iterative 3D EPT reconstruction.

1179. Electric Properties Tomography: Calculation of the In-Vivo Electric Field Within Realistic Computation Times Using Quasi-Stationary Zooming Cornelis A.T. Van den Berg1, Mikel Boute1, Bob Van den Bergen1, Jan J.W. Lagendijk1, Ulrich Katscher2 1University Medical Center Utrecht, Utrecht, Netherlands; 2Philips Research Europe-Hamburg, Hamburg, Germany

Electric Properties Tomography (EPT) is a method to determine the dielectric properties during an MRI scan. It can be used as a diagnostic parameter or more precise local SAR assessment. Using an iterative computation scheme the dielectric properties are determined from the curl of the measured transverse magnetic field and a calculated axial electric field distribution. Conventional methods such as FDTD solvers are too slow to calculate the electric field with millimetre resolution. We successfully tested a method called quasi-stationary zooming that reduced the computation time with a factor of 20 without serious degrading the EPT results.

1180. Empirical and Computed B0 Perturbations Induced by Metallic Implants Kevin M. Koch1, R Scott Hinks1 1GE Healthcare, Waukesha, Wisconsin, USA

Metallic implants used in arthroplasty procedures can induce severe spatial B0 perturbations and significantly distort conventional MRI. Information on the nature of these field perturbations has previously been difficult to assess. Here, it is demonstrated that FFT-based computations of approximated solutions to Maxwell’s equations can be used to rapidly and accurately predict high-resolution B0 distributions induced by metallic implants. A novel method is also presented that allows for MR-based collections of far-off resonance (>8kHz) contour B0 maps. The presented techniques are utilized to determine the previously unpublished magnetic susceptibility of a commonly used cobalt-chromium metal alloy.

Poster Sessions

216

1181. A Physical Shepp-Logan Head Phantom Julian R. Maclaren1, Philip Bones1, Rick P. Millane1, Richard Watts1 1University of Canterbury, Christchurch, New Zealand

An MR-compatible Shepp-Logan head phantom has been constructed from layers of polycarbonate. When imaged using the correct slice thickness, the partial volume effect generates the required contrast values for each region. This phantom can be used to validate simulations conducted using the well-known numerical version. The physical phantom has been combined with a computer controlled moving platform to allow the effect of motion on various pulse sequences to be studied. This abstract compares data obtained from the physical phantom with data generated using the mathematical model of the Shepp-Logan head phantom.

1182. B1 Field Optimization for Microstrip Transmission Line Volume Coil at High Field Chunsheng Wang1, Xiaoliang Zhang1 1University of California San Francisco, San Francisco, USA

B1 field distributions within MTL head coils with different substrate thickness were investigated by finite difference time domain method. Although the B1 field homogeneity can be improved by increasing substrate thickness of MTL coils for unloaded case, the B1 field homogeneity of MTL coils after loading can be optimized by selecting appropriate substrate thickness by making use of ¡®dielectric resonance¡¯ effect.

1183. Numerical Model of a Dielectric Resonator for High Field MRI Bu Sik Park1, Andrew G. Webb2, Michael B. Smith3, Christopher M. Collins3 1Penn State University, College of Medicine, Hershey, Pennsylvania, USA; 2Penn State University, University Park, Pennsylvania, USA; 3Pennsylvania State University, Hershey, Pennsylvania, USA

Based on previous research, we have designed a dielectric resonator of barium strontium titanate (having a dielectric constant of 323) with a diameter of 28 mm for high field MRI and performed full Maxwell numerical calculations of the electromagnetic fields to evaluate the resonator. The cylindrical dielectric resonator has a region of low loss and high sensitivity along its central axis, and should provide lower sample loss than (for example) a solenoid design, which is found to produce a significant electric field in the sample due to the electrical potential on the wires.

1184. A New Analytical Approach to RF Coils at High Frequency: the Spiral Coil Example Xin Chen1, Xingxian Shou1, Hiroyuki Fujita, 12, Victor Taracila3, Robert W. Brown1 1Case Western Reserve University, Cleveland, Ohio, USA; 2Quality Electrodynamics, LLC., Mayfield Village, Ohio, USA; 3GE Healthcare, Aurora, Ohio, USA

RF field inhomogeneity continues to be a major challenge in today’s high-field MRI. The RF wavelength is significantly shortened in biological samples due to a high dielectric constant, leading to field nonuniformities. We present a new analytical approach that is robust for optimization studies. As an example, we analyze a spiral coil, with special attention paid to the interplay between transverse and axial wavelength effects. The analytical results are consistent with previously published experiments and preliminary numerical simulations. An optimized spiral coil leads to improved field homogeneity, relative to the birdcage coil, up to (at least) 400MHz.

1185. A Numerical Analysis of Conservative and Magnetically-Induced Electric Field for Low-Frequency Human Imaging Bu Sik Park1, Christopher M. Collins2 1Penn State University , Hershey, Pennsylvania, USA; 2Penn State University, Hershey, Pennsylvania, USA

Although it is generally believed that almost all of the sample loss for the Birdcage Coil is magnetically-induced, there have been some suggestions that conservative E-fields may play a significant role, including suggestions that low-pass (LP) and high-pass (HP) BCs have significantly different E-field distributions (and may couple to the human subject very differently) due to their differing capacitor placement. Here we apply a recently-developed method to evaluate the conservative and magnetically-induced E-fields, as well as the sample power loss for a birdcage coil loaded with the head.

1186. Investigation of Mutual Inductance Coupling and Capacitive Decoupling of N-Element Array System Lian Xue1, L.-M Xie1, Maged R. Kamel1, Flora Ip1, Jarek Wosik1, Alexander C. Wright2, Felix W. Wehrli2 1University of Houston, Houston, USA; 2University of Pennsylvania Medical Center, Philadelphia, USA

We report on the analyzes of the inductive coupling and capacitive decoupling of N-element array resonant system. A two-state rf current direction model for magnetically coupled coils was developed to calculate number of possible resonant modes in N-element array. We have obtained an analytical solution for number of possible frequency modes in a symmetric resonant linear and circular system of N-element array. Decoupling was achieved by using a set of capacitors to reduce the frequencies of higher modes to the lowest mode frequency. Examples of capacitive-only decoupling of 2x1, 2x2 and 4x1 arrays are shown and mechanism of such decoupling is analyzed.

1187. Exchange of Surface Coil Antenna Patterns Due to Gyrotropism Cornelius von Morze1, 2, Albert Pofu Chen1, Duan Xu1, Daniel B. Vigneron1, 2, James Tropp3 1UCSF, San Francisco, USA; 2UCSF/UCB Joint Graduate Group in Bioengineering, San Francisco, USA; 3GE Healthcare, Fremont, USA

A recent formulation of NMR reciprocity that accounts for the gyrotropism of spins was tested through experiments on oppositely polarized 3.0T MRI scanners. The transmit and receive antenna patterns of a surface coil are distinct, and furthermore exchange on field reversal. The receive patterns of a bilaterally symmetric dual array were first measured through a receive-only experiment. Following the proper pattern exchanges and multiplications, these results predicted the distinct appearance of images obtained by operating the coil in transmit-receive mode on oppositely polarized systems.

Poster Sessions

217

1188. Fast, Accurate Calculation of Maximum Local N-Gram Specific Absorption Rate Adam Charles Zelinski1, Vivek K. Goyal1, Elfar Adalsteinsson1, 2, Lawrence L. Wald, 23 1MIT, Cambridge, Massachusetts, USA; 2Harvard-MIT Division of Health Sciences & Technology, Cambridge, Massachusetts, USA; 3Harvard Medical School, MGH, Charlestown, Massachusetts, USA

SAR is a major concern in MRI; it is crucial to be able to quickly and accurately calculate maximum N-gram local SAR due to a pulse. In contrast with low-resolution models that lack many compartments and have overly-smooth tissue-boundaries, high-resolution models permit accurate local SAR calculations. Unfortunately, the fine resolution of such models makes calculating average N-gram SAR at each location a computationally intractable problem (straightforward region-growth methods may no longer be used). We pose a rapid algorithm that is equal in speed to the fixed-cube method, yet always averages over a N-gram region, ensuring accuracy of local SAR estimates.

1189. Phased Array Evaluation Using a Human Body Model at 3T Selaka Bandara Bulumulla1, Christopher J. Hardy1 1GE Global Research, Niskayuna, USA

We use an anatomically accurate human body model with distinct electrical properties for different tissue types for evaluating the SNR of a 16-element phased array used for body imaging at 3T. Using numerical methods, we estimate the electromagnetic fields in the model and calculate an intrinsic SNR metric to evaluate the imaging performance of the array. The results highlight many of the artifacts common in 3T imaging, including left-right shading arising from wavelength effects. This method can be used to evaluate the imaging performance of a given array, and to optimize array configurations at various field strengths.

1190. Lower RF Power Absorption Combined with Uniform Excitation Using Multi-Port B1 Shimming: Numerical Simulations and Experiments at 7T Lin Tang1, YiK-Kiong Hue2, Tamer S. Ibrahim, 12 1University of Oklahoma, Norman, Oklahoma, USA; 2University of Pittsburgh, Pittsburgh, Pennsylvania, USA

We show using the finite difference time domain method that improving the B1+ field homogeneity over 3-D regions with volumes as large as the whole head while simultaneously reducing the total RF absorption by human head to values lower than that associated with quadrature excitation can be achieved at 7T. The concept of B1 shimming with reduced RF power absorption was validated using a 7T whole-body system with a Tx array.

1191. Estimation of Local SAR Using B1 Mapping Ulrich Katscher1, Tobias Voigt2, Christian Findeklee1, Kay Nehrke1, Steffen Weiss1, Olaf Doessel2 1Philips Research Europe - Hamburg, Hamburg, Germany; 2University Karlsruhe, Karlruhe, Germany

The local specific energy absorption rate (SAR) is one of the major issues for MRI at 3T and above. For an exact determination of local SAR, the spatial distribution of the electric field and electric conductivity throughout the patient are required. Alternatively, according to Maxwell's equations, the required quantities can be deduced by the magnetic field of the RF coil. In this study, the local SAR is estimated via suitable post-processing of a standard B1 map. Simulations show, that the information content of a B1 map might be sufficient to estimate local SAR close to the correct local SAR.

1192. A BiCG Solution Based Quasi-Static Finite-Difference Scheme for Induced Field Evaluation in MRI Hua Wang1, Feng Liu1, Adnan Trakic1, Stuart Crozier1 1The University of Queensland, Brisbane, Australia

This study presents a biconjugate gradient method (BiCG) that can significantly improve the performance of the quasi-static finite-difference scheme, which has been widely used to model field induction phenomena in voxel phantoms. The proposed BiCG method offers remarkable computational advantages in terms of convergence performance and memory consumption over the conventional iterative, successive over-relaxation algorithm. The wide application capability and computational performance of the BiCG method is demonstrated by modelling the exposures of MRI healthcare workers to fields produced by pulsed field gradients, which is presently an important topic of research in light of the Physical Agents Directive 2004/40/EC.

1193. A Complete Modeling System with Experimental Validation for Calculating the Transmit and Receive Fields, Total Power Deposition, Input Impedance, and Coupling Between Coil Elements YiK-Kiong Hue1, Tiejun Zhao, Yongxian Qian1, Fernando E. Boada1, Tamer S. Ibrahim1 1University of Pittsburgh, Pittsburgh, Pennsylvania, USA

A complete finite-difference time-domain (FD-TD) model of a highly coupled RF coil is provided at 7T. Experimental results that validate all of the coil’s (while loaded) electromagnetic characteristics (calculated using the FD-TD method) including coupling, excite and receive field, input impedance, and total RF power deposition are presented.

1194. Time-Domain Finite-Difference/Finite-Element Hybrid Simulations of High-Field RF Coils Shumin Wang1, Jeff H. Duyn1 1LFMI/NINDS/NIH, Bethesda, Maryland, USA

A Time-Domain Finite-Difference/Finite-Element (TD-FD/FE) hybrid method was developed to simulate high-field RF coils with realistic modeling of both the human body and the RF coils. The FEM is only applied to model curved coil structures while the human body is simulated by the FDTD method. Since both methods are applied simultaneously in a same simulation, the interaction between the human body and RF coils are fully accounted for with well balanced accuracy and efficiency. Numerical results demonstrate the validity, accuracy and capability of this approach.

Poster Sessions

218

1195. Ultra-Fast Electromagnetic Field Computation for RF Shimming, Parallel Transmission and Coil Design Bob van den Bergen1, Chris C. Stolk2, Jan Bouwe van den Berg3, Cornelis A. T. van den Berg1 1University Medical Center Utrecht, Utrecht, Netherlands; 2University of Twente, Enschede, Netherlands; 3VU University Amsterdam, Amsterdam, Netherlands

RF shimming and parallel transmission have shown to be able to improve the image quality and reduce the SAR for high field MR imaging. However, both methods require information about the electromagnetic fields, of which only the magnetic part can be measured. FDTD calculations have become standard as alternative to measurements, although these calculations are time-consuming and therefore unsuitable for on-line use. We present a new method that can calculate the electric and magnetic field in the body in one or two minutes, thereby increasing the on-line feasibility of both RF shimming and parallel transmission drastically.

1196. Transmit and Receive FDTD Modeling as a Valuable Tool for RF Coil Development: Validation of Simulations with in Vivo Torso Imaging at 7 Tesla Can Akgun1, Carl J. Snyder1, Steen Moeller1, Pat John Bolan1, Thomas Vaughan1, Kamil Ugurbil1, Pierre-Francois Van de Moortele1, Greg Metzger1 1University of Minnesota, Minneapolis, Minnesota, USA

In an era where large arrays and complex geometries are being proposed for UHF to maximize parallel imaging performance, B1+ shimming flexibility, and receive sensitivity, the ability to predict transmit and receive characteristics in vivo becomes imperative. In support of our 7T prostate imaging, we measured in vivo B1+ maps and g-factor maps with 8- and 16-channel phased array coils and found the results were correctly predicted by simulations using Remcom’s XFDTD software. These findings build confidence in our ability to evaluate SAR for the development of future optimization procedures, as well as guiding future RF coil development.

MR-Guided Interventions (Non-Thermotherapy) Hall D Thursday 13:30-15:30

1197. Cardiovascular MR Imaging is a Platform for Percutaneous Transendocardial Delivery and Assessment of Gene Therapy Maythem Saeed1, Alastair J. Martin1, Alexis Jacquier1, Loi Do1, Matthew Bucknor1, Charles B. Higgins1, David Saloner1 1University of California San Francisco, San Francisco, California , USA

MR fluoroscopy was used for guiding transendocardial delivery of plasmid VEGF and for evaluating myocardial perfusion, viability and function in occlusive infarction. A mixture of plasmid VEGF and LacZ or plasmid LacZ and Dy-DTPA-BMA were delivered into the border and core of MR hyperenhanced infarcted region. At 7-8 wks, plasmid VEGF increased ejection fraction, perfusion, vascularity and decreased infarcted region on MR imaging and histochemical staining. MR imaging was successfully used in guiding delivery of genes and assessing myocardial viability and function. The effectiveness of this approach most likely stems from VEGF effects on neovascularization in scar tissue.

1198. MR-Guided Biopsy Targeting Transplanted MR-Visible Magnetocapsules (MCs) Containing Human Islets David Arthur Woodrum1, Thomas Link2, Wesley D. Gilson2, Christine H. Lorenz2, Dara L. Kraitchman2, Jeff WM Bulte2, Aravind Arepally2 1Mayo Clinic, Rochester, Minnesota, USA; 2Johns Hopkins University School of Medicine, Baltimore, Maryland, USA

Magnetic resonance (MR)-trackable magnetocapsules (MCs) were created to simultaneously immunoprotect pancreatic beta cells and non-invasively monitor, in real-time, portal vein delivery and engraftment using MR imaging (MRI). The purpose of this study was to demonstrate the feasibility of MR-guided targeted biopsy of MCs containing human islets to assess viability and function. MR-compatible 14g biopsy needle was tracked (using a passive artifact from the needle) and steered into the four quadrants of the liver using a real-time sequence through a percutaneous access. By utilizing MRI, needle placement close to the MCs was ensured and core biopsies were obtained.

1199. Endoluminal In-Vivo High-Resolution MR Imaging of the Esophageal Wall with Histological Correlation Sherif G. Nour1, 2, Jens O. Heidenreich1, Jamal J. Derakhshan, Simi Paul1, Fadi W. Abdul-Karim1, Mark A. Griswold1, Vikas Gulani1, John Jesberger, Philip A. Linden1, Jeffrey L. Duerk1 1University Hospitals Case Medical center / Case Western Reserve University, Cleveland, Ohio, USA

Esophageal cancer affects 5/100,000 people in the USA. 5-year survival rate is <10% despite therapeutic advances. Accurate staging and appropriate treatment rely on determining the depth of tumor invasion through the esophageal wall. Here, a catheter-mounted receiver coil was used to obtain in-vivo high-resolution images of esophageal wall. The performance of various MR-pulse sequences was tested, imaged segments were harvested, and images were correlated with histology. Results show that high-resolution esophageal wall MRI is feasible with commercially-available imaging catheters and there is high correlation with histology in delineating various layers of normal esophageal wall as required for future MR staging.

1200. PSIF Imaging with Outer Volume Suppression for Percutaneous Interventions Jaane Rauschenberg1, Wolfhard Semmler1, Michael Bock1 1Deutsches Krebsforschungszentrum (dkfz), Heidelberg, Germany

In percutaneous MR-guided interventions imaging can be significantly accelerated by inner volume excitation or outer volume suppression, which restricts the phase encoding FOV. The combination of outer volume suppression with steady state pulse sequences such as PSIF is challenging, as conventional suppression pulses lead to a violation of the steady state condition. Here, a new integrated outer volume suppression technique, which maintains the steady state, is presented and evaluated in phantom and volunteer experiments.

Poster Sessions

219

1201. Image Fusion Techniques for Integrated MR-Endoscope System Makiya Matsumoto1, Yuu Shoji1, Yuichiro Matsuoka2, Etsuko Kumamoto1, Kagayaki Kuroda2, 3, Toshiya Kaihara1 1Kobe University, Kobe, Japan; 2Institute of Biomedical Research and Innovation, Kobe, Japan; 3Tokai University, Hiratsuka, Japan

We have devised image fusion techniques for the integrated MR-endoscope system, in which real time MR scanning is performed with an intraluminal surface coil during endoscopic observation and surgery for gastrointestinal applications. To navigate the scope and to match the scope coordinates with that of the scanner, wireless resonators with Gadolinium-absorbed gel were developed. For the image fusion, the MR images were deformed numerically with a fifth order, two dimensional approximation function obtained from the optical distortion of the scope view, after appropriate Affine-transformations for scaling and trapezoidal conversion were applied.

1202. Motion-Corrected Intravascular MRI with an Active Tracking Catheter Ann-Kathrin Homagk1, Sven Müller1, Peter Hallscheidt2, Marc-Andre Weber1, Wolfhard Semmler1, Michael Bock1 1Deutsches Krebsforschungszentrum (dkfz), Heidelberg, Germany; 2University Heidelberg, Heidelberg, Germany

The present study proposes a method of acquiring intra-arterial images using additional MR tracking information. An imaging and tracking pulse sequence was implemented and tested on a healthy anesthetized pig. The position of the tracking catheter tip was continuously extracted from projection data to use them for retrospective gating of the acquired images. For motion compensation, a range of positions was defined which were accepted as input for the subsequent image calculation. A comparison between motion-corrected images and uncorrected images showed that the use of projection data for motion correction leads to a significant improvement in image quality.

1203. 3D MRI-Guided Passive Catheter Tracking and Visualization Using HYPR-Based Techniques Orhan Unal1, 2, Julia Velikina1, Charles M. Mistretta1 1University of Wisconsin, Madison, Wisconsin, USA

Catheter tracking and visualization require both good spatial and temporal resolution. Recently developed HighlY constrained back PRojection (HYPR)-based techniques in combination with radial or hybrid radial/Cartesian acquisition techniques provides relatively artifact free images with large undersampling factors and is therefore well-suited for MRI-guided passive catheter tracking and visualization applications.

1204. Reverse Polarization Method for Catheter Tracking: Phased Array Coil Studies and Real-Time TSENSE Implementations Haydar Celik1, Michael A. Guttman2, Onur Kocaturk2, Christina Saikus2, Kanishka Ratnayak2, Anthony Faranesh2, Andrew Derbyshire2, Robert Lederman2, Ergin Atalar1, 3 1Bilkent University, Ankara, Turkey; 2National Institude of Health, Bethesda, Maryland, USA; 3Johns Hopkins University, Baltimore, Maryland, USA

In MRI-guided vascular interventions, visualization of interventional devices is rather difficult. For this purpose many tracking techniques have been developed. In one of these studies, reverse polarized signal was acquired using a receive-only birdcage coil in order to separate the anatomical information from a catheter which contains a receive coupled RF (RCRF) coil.In present work, the reverse polarization method has been implemented to phased array coils and real-time experiments have been conducted on phantom using TSENSE algorithm. As a result, reverse polarization mode of image, which consists of the catheter, and color-coded image are obtained. In order to show safety profile, phantom heating experiments were conducted.

1205. Automated Tracking of a Passive Endomyocardial Stiletto Catheter with Dephased FLAPS MRI: A Feasibility Study Ioannis Koktzoglou1, 2, Sotirios A. Tsaftaris3, Sven Zuehlsdorff4, Debiao Li2, Aggelos K. Katsaggelos3, Rohan Dharmakumar2 1Evanston Northwestern Healthcare, Evanston, Illinois, USA; 2Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA; 3Northwestern University, Evanston, Illinois, USA; 4Siemens Medical Solutions, Chicago, Illinois, USA

Automated tracking of a passive stiletto catheter for regenerative myocardial therapy under the MR environment may improve the accuracy ofthe procedure. We report successful implementation of automated computer-assisted tracking for this purpose in a controlled phantom study.

1206. Non-Excitory Steady-State Interference Elimination (NESSIE) MRI Fiducial Tracking Donald W. McRobbie1, Marc Rea1 1Imperial College Healthcare NHS Trust, Charing Cross Hospital, UK

Inductively coupled fiducial markers have an inconsistent appearance on MR images.The Non-Excitory Steady-State Interference Elimination (NESSIE) pulse sequence has been developed to remove this imaging sequence dependence. The contrast of the fiducials can be controlled independently from the background anatomy using NESSIE pre-pulses, potentially improving MR tracking during interventions.

1207. Catheter Visualization Using Rubber Bands and Ultrashort TE Imaging Juergen Rahmer1, Sascha Krueger1 1Philips Research Europe, Hamburg, Germany

Increasingly, interventional procedures rely on MR imaging for tracking of catheters in the body. Active catheter visualization allows highlighting the tip position in a standard MR image, but requires additional equipment and dedicated catheters. In contrast, passive visualization requires only minimal device modification. Typically, susceptibility markers are attached to the device to cause local contrast in the image. However, this contrast effect is permanent and can negatively affect the anatomical information in the MR image. We propose to use short-T2 material with T2 shorter than about 1 ms as a passive marker. This material does not interfere with standard MR imaging, but can be visualized using ultrashort echo-time (UTE) sequences. This work demonstrates the passive visualization of the full catheter length using 3D UTE imaging of short-T2 rubber bands inserted into the catheter.

Poster Sessions

220

1208. Rubber Materials for Active Device Tracking Reiner Umathum1, Michael Bock1 1Deutsches Krebsforschungszentrum (dkfz), Heidelberg, Germany

Active device tracking is challenging in anatomical areas such as the lung where no MR signal is present. To overcome this limitation, a signal reservoir needs to be integrated into the tracking coil; however, these reservoirs require frequent re-filling. In this work we propose semi-solid rubber materials for MR tracking which are long-term stable. Due to their short T2* relaxation times, pulse sequences with ultra-short TE below 1 ms need to be used for device tracking.

1209. A Novel Intravascular MRI Coil with Optimized Sensitivity Stephan Fandrey1, Steffen Weiss2, Jörg Müller1 1Hamburg University of Technology, Hamburg, Germany; 2Philips Research Europe , Hamburg, Germany

A modified micro Helmholtz coil was designed for intravascular imaging and tracking with the objective to achieve maximum homogeneity of the coil sensitivity in the surrounding medium. The optimal design was determined using finite element simulations. Foil-based micro-Helmholtz-coils were fabricated with this design using planar micro systems technology and mounted on a 5F catheter tube. The sensitivity pattern of the coils was evaluated in phantom experiments and found to be conform with the simulation results. The use of micro systems technology allows coil fabrication in large batches with high reproducibility.

1210. Ground Pad for Better Look-Ahead Visualization in Guidewire Imaging Lizabeth Y. Li1, William R. Overall1, Greig C. Scott1, John M. Pauly1 1Stanford University, Stanford, California , USA

We apply the use of a grounding pad in combination with a wire receiver antenna to increase signal intensity in front of the wire tip for use in interventional MRI, offering a significant improvement in look-ahead visualization over a guidewire receiver antenna only. The ground pad directs the current density off of the wire, increasing the receiver B1 field and the resulting signal. With different positioning of the return current path from the ground pad, we can also selectively increase the signal intensity at locations near the front of the guidewire.

1211. MR-Assisted Retrograde Drilling of Osteochondral Lesions of the Talus - A Feasibility Study - Christian Seebauer1, Florian Wichlas1, Jens Rump1, Jens Pinkernelle1, Ioannis Papanikolaou1, Tobias Jung1, Sascha Chopra1, Ulf Teichgräber1, Hermann Josef Bail1 1Charité, Berlin, Germany

Osteochondrosis dissecans is a localized subchondral aseptic bone necrosis. However, its pathogenesis is still controversial. Various operative techniques for the treatment of osteochondral lesions of the talus with varying success have been reported. MRI yields additional information on the vitality and stability of the osteochondral fragment and allows differentiating the surrounding tissue, providing information on the fixation of the fragment. Here, we propose an innovative method for the retrograde drilling of necrotic areas in the talus using a MR-compatible drilling guide.

1212. Novel Circumferential Immobilization of Breast Tissue Displacement During MR-Guided Procedures: Initial Results Matthew Smith1, Xu Zhai1, Ray Harter2, Sean Fain1 1University of Wisconsin, Madison, Wisconsin, USA; 2Marvel Medtech LLC, Madison, Wisconsin, USA

The performance of image-guided devices for breast procedures is dependent on how well the tissue is stabilized during interventions. Novel MR-compatible devices for breast interventions have been previously developed by various groups using conventional 2D compression plates for breast tissue immobilization during a procedure. However, these devices typically distort the anatomy and cause discomfort for many women. We find that tissue is sufficiently immobilized during a trocar insertion with a 3D tissue immobilization concept using circumferential air bladders compared to an insertion without immobilization. Patient studies are planned to optimize the bladder shape and evaluate the required stabilization pressure.

1213. An MR Compatible Tactile Sensor Array for Palpation-Based Diagnosis and Noise Analysis in MR Environment Zion Tsz Ho Tse1, Abbi Hamed1, Michael Lamperth1 1Imperial College London, London, UK

In this research piezoelectric sensors are utilized for force sensing and developed into an array for the purpose of inner-body palpation using an endoscope system. The sensors are shown to be MR compatible and highly sensitive and will output a charge signal on the slightest deformation (micron scale), however this property and their highly capacitive nature also entail that they are very sensitive to interference from the noisy scanner environment and hence significant attention must be paid into attenuating unwanted signals before they can present a serviceable transduction solution.

1214. Navigation System for Interventional MR Image Guidance in a Closed-Bore Scanner: System Setup and Estimation of Targeting Accuracy Harald Busse1, Robert Trampel1, 2, Wilfried Gründer3, Nikita Garnov3, Jochen Fuchs1, Tim-Ole Petersen1, Thomas Kahn1, Michael Moche1 1Leipzig University Hospital, Leipzig, Germany; 2Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; 3Leipzig University, Leipzig, Germany

The ongoing development of powerful MR imaging techniques also allows for advanced possibilities to guide and control minimally invasive interventions. Various navigation concepts have already been described for practically all regions of the body. Most diagnostic scanners, however, do not allow the physician to guide the instrument inside the magnet and, consequently, the patient needs to be moved out of the bore. The purpose of this work was to present a concept for real-time navigation with automatic patient registration and interventional control for a closed-bore scanner and to provide first estimates on the overall targeting accuracy in an experimental setup.

Poster Sessions

221

1215. 3D Real-Time Tracking Using Passive Fiducial Markers and Image Processing Marc A. Rea1, 2, H Elhawary2, Zion T. Tse2, Donald W. McRobbie, 12, Michael Lamperth2, Ian Young2 1Charing Cross Hospital, London, UK; 2Imperial College London, London, UK

This abstract reports the implementation of an imaging methodology enabling real-time 3-dimensional tracking of devices using only passive micro-coil fiducials and image processing. A modified FLASH sequnce was executed with a minimum update rate of 1.8 seconds, sufficient for tracking movements up to 7mm/s. Using a MRI-compatible manipulator, prostate phantom lesions were successfully targeted with a maximum accuracy of 0.5mm.

1216. Imaging-Guided Percutaneous Punctures Using a Combined MR Imaging / C-Arm CT Approach: A Pilot Study Assessing the Feasibility Bernhard C. Meyer1, Alexander B. Brost2, Liron Yatziv3, Norbert Strobel4, Wesley Gilson5, Karl Juergen Wolf1, Jonathan S. Lewin6, Frank K. Wacker, 16 1Charite - Universitätsmedizin Berlin, Berlin, Germany; 2Universität Erlangen, Erlangen, Germany; 3Siemens Corporate Research, Princeton, New Jersey, USA; 4Siemens Medical Solutions, Forchheim, Germany; 5Siemens Corporate Research, Baltimore, Maryland, USA; 6Johns Hopkins University, Baltimore, Maryland, USA

Purpose: To test the use MR images augmented on C-arm CT images to guide needle punctures in phantoms. Method: 10 punctures with 6 mm radius ring targets and 2 punctures of 15-20 mm cysts were performed. MR based fluoroscopic guidance was used.Result: The needle tip was correctly placed in 8/10 rings with a maximum distance to the center of 5mm. The cyst punctures were successful with a needle deviation of 10 and 8 mm.Conclusion: The combination of preacquired MR images, C-arm CT and fluoroscopy allows puncture of lesions not visible with fluoroscopy and hardly accessible using MR.

1217. Advanced Communication Device for Interventional MR Communication and Talking Margarita Con Lima1, James Bean, Thomas Collins 1Lima Institute for Advanced Studies, Lima, Peru

An advanced, MR compatible communication device for interventional MR is presented. It is made of space age polymers and fibers, and can transmit audio data up to three meters with only 98% losses.

Thermal Therapy & HIFU Hall D Monday 14:00-16:00

1218. Temperature Mapping Close to the Surface of Ultrasound Transducers Using Susceptibility-Compensated MRI Andrew Webb1, Eun-Joo Park, Thomas Neuberger, Nadine Smith 1Penn State University, University Park, Pennsylvania, USA

An MRI technique for non-invasively mapping temperature increases close to the surface of an ultrasound transducer is presented. Using conventional sequences, image artifacts caused by the magnetic susceptibility of the ultrasound transducer preclude this type of measurement. Using susceptibility-compensating sequences, temperature measurements can be obtained ~1 mm from the transducer surface. Applications to phased array cymbal tranducers used for non-invasive insulin delivery are shown.

1219. MR-Temperature Maps of a HIFU CMUT Serena H. Wong1, Ronald D. Watkins1, Mario Kupnik1, Kim Butts-Pauly1, Butrus T. Khuri-Yakub1 1Stanford University, Stanford, California , USA

Noninvasive surgeries with high intensity focused ultrasound (HIFU) under MR guidance are becoming more popular. Though piezoelectric transducers have been used traditionally for these applications, capacitive micromachined ultrasonics transducer(CMUT) have shown advantages in ease of fabrication, efficient performance, and minimal self-heating. We demonstrate heating of a gel phantom using HIFU from an unfocused CMUT and also monitoring of this heating using MR-temperature maps in a 3.0 T scanner.

1220. 3T MR Phased Array as a Hyperthermia Applicator Selaka B. Bulumulla1, Arjun Arunachalam1, Keith J. Park1, Thomas K. Foo1, Yudong Zhu1 1GE Global Research Center, Niskayuna, USA

Overlapping coil arrays have been used as phased array receivers in parallel receive schemes as well as transmit elements in parallel transmit schemes. In this work, we consider surface coil arrays excited by continuous wave RF sources as RF hyperthermia applicators for oncology. Using numerical analysis and experimental work, we study the heating patterns from loop elements and demonstrate the feasibility of selective heating from surface coils. The resulting array has the potential to function as parallel transmitters and phased array receivers for diagnostic imaging as well as an applicator for hyperthermia oncology therapy.

1221. Evaluation of Nanoshell Mediated Tumor Ablation with Real Time Multiplanar MR Temperature Imaging in a Canine Brain Tumor Model Anil Shetty1, Roger Price, Jon Schwartz, Rajesh Uthamanthil1, James Wang, Andrew Elliott1, John D. Hazle1, R Jason Stafford1 1The University of Texas M.D.Anderson Cancer Center, Houston, USA

A controlled minimally invasive alternative for brain tumor treatments is nanoshell mediated heating with intratumoral fiber placement. These particles are configured to preferentially absorb near-infrared (NIR) light and to emit heat through the process of surface plasmon resonance. Preferential damage was seen on the tumor side in a canine brain tumor model, with minimal damage in the contralateral normal brain. The tumor heated up to a higher lethal temperature (~18¢ªC), compared to the contralateral control side. These preliminary results prove the efficacy of these nanoshells to deliver lethal damage to the tumor in a minimally invasive manner.

Poster Sessions

222

1222. Validation of Percutaneous MRI-Guided Laser Ablation with Real-Time MR Temperature Monitoring in a Canine Prostate Model Anil Shetty1, Roger McNichols, Ashok Gowda, Sherry Klumpp1, Andrew Elliott1, Agatha Borne1, David Brammer1, John D. Hazle1, R Jason Stafford1 1The University of Texas M.D.Anderson Cancer Center, Houston, USA

The goal was to validate the efficacy of using a MR-registrable perineal template to percutaneously guide and execute multi-fiber laser treatment in a canine prostate model with real-time MR temperature monitoring. The maximum discrepancy between the actual signal void from the laser catheter and the center of the predicted trajectory was less than 1 mm. Real-time monitoring detected a maximum temperature rise of ~ 50 ¢ªC. This minimally invasive approach to laser ablation of tissue in the prostate performed well, with a maximal positional error of less than 1 mm at an insertion depth of 6 cm.

1223. Perfusion Calculation Based on MR-Temperature Maps and Focused Ultrasound Heating. Theoretical and Experimental Study Iulius Dragonu1, Philippe Lourenço de Oliveira1, Christophe Laurent, 12, Baudouin Denis de Senneville1, Charles Mougenot, 13, Chrit Moonen1, Bruno Quesson1 1Laboratory for Molecular and Functional Imaging, Bordeaux, France; 2Saint André Hospital, Service de Chirurgie Digestive, Bordeaux, France; 3Philips Medical Systems, Suresnes, France

The objectives of the present work were to propose a method for quantitative estimation of perfusion rate, thermal diffusivity and energy absorption coefficients and to evaluate the pertinence of the bio-heat transfer equation (BHTE) to model the temperature distribution in presence of perfusion. Ex vivo kidneys were heated with HIFU under 3D thermometry, varying the input flow. Excellent concordance was observed between the theoretical description and the experimental results. This method allows for automatic determination of tissue thermal properties which influence the efficiency of thermotherapy in highly perfused organs.

1224. Contribution of Temperature Dependent T1-Change, Slice Thickness and Positioning to an Artifact in Temperature Images of FUS Heating Viola Rieke1, Kim Butts Pauly1 1Stanford University, Stanford, California , USA

The PRF-change with temperature is frequenctly used to monitor focused ultrasound (FUS) ablation. Because the heating area with FUS is small, partial volume effects are common. In addition, temperature dependend T1-changes can influence PRF based temperature measurements. In this work, we are investigating how partial volume effects, slice position, and temperature dependent T1-changes can influence PRF-based temperature measurements during FUS ablation.

1225. Referenceless Multi-Coil Reconstruction Viola Rieke1, Rexford Newbould1, Roland Bammer1, Kim Butts Pauly1 1Stanford University, Stanford, California , USA

Referenceless PRF thermometry estimates the phase due to a temperature rise in the heating region from the background phase and, therefore, does not need a baseline image for image subtraction. To estimate the background phase the phase images have to be smooth after phase unwrapping. We describe a phase reconstruction method for multi-coil acquisitions that prevents phase discontinuities to allow the combined images to be reconstructed with the referenceless method.

1226. 3D Navigated Real-Time Thermometry for Abdominal Imaging Max Köhler1, Gregory Maclair2, Baudouin de Senneville2, Chrit Moonen2, Mario Ries2 1Philips Medical Systems, Finland; 2IMF, CNRS / Univ. Bordeaux2, Bordeaux, France

This work presents a combination of slice tracking combined with 2D image registration and look-up table based phase corrections for 3D navigated real-time MR-thermometry on abdominal organs.

1227. Real-Time Correction of Respiratory-Induced Field Disturbances for PRFS-Based MR-Thermometry in the Human Breast Silke Hey1, Gregory Maclair1, Baudouin de Senneville1, Yasmina Berber1, Bruno Quesson1, Chrit Moonen1, Mario Ries1 1IMF, CNRS / Univ. Bordeaux2, Bordeaux, France

Real-time MR-thermometry based on the proton resonance frequency (PRF) technique allows monitoring of the local temperature evolution during radio-frequency, laser, cryogenics or focused ultrasound thermal ablation. Especially in the human breast, the presence of magnetic field fluctuations induced by the respiratory cycle can lead to thermometry artefacts if no correction is applied. For this purpose a look-up-table-based multi-baseline correction algorithm based on pencil-beam navigator data is applied to MR-thermometry to correct for the periodic B0-field changes. The feasibility of the correction method in real-time is demonstrated experimentally in a healthy volunteer using pencil-beam navigators for respiratory control.

1228. A Hybrid PRF/T1 Pulse Sequence for Rapid, Simultaneous Temperature Tracking in Soft and Adipose Tissues Nick Todd1, Dennis L. Parker 1University of Utah, Salt Lake City, Utah, USA

Here we present a hybrid PRF/T1 pulse sequence capable of measuring those two temperature dependent parameters rapidly and simultaneously. The PRF information is acquired in the usual, using a gradient echo sequence. The T1 information is extracted by varying the flip angle between consecutive scans and using the relation between signal intensity, T1 and flip angle. This method allows the TR of the sequence to remain fixed, and keeps scan time short enough for real time temperature tracking. Results from an oil/water heating experiment demonstrate the pulse sequences ability to monitor temperature changes in both water-based and fat-based substances.

1229. Hot Spot Tracking for Focused Ultrasound Surgery of Liver Using Filtered Venography Daisuke Kokuryo1, Etsuko Kumamoto2, Atsuya Okada3, Takamichi Murakami4, Susumu Fujii5, Toshiya Kaihara1, Kagayaki Kuroda6, 7 1Graduate School of Engineering, Kobe University, Kobe, Japan; 2Information Science and Technology Center, Kobe University, Kobe, Japan; 3The Center of Imaging Assisted Minimally Invasive Therapy, Iseikai Hospital, Osaka, Japan; 4School of Medicine,

Poster Sessions

223

Kinki University, Sayama, Japan; 5Faculty of Science and Technology, Sophia University, Japan; 6Graduate School of General Science and Technology, Tokai University, Hiratsuka, Japan; 7Molecular Imaging Research Group, Institute of Biomedical Research and Innovation, Kobe, Japan

A target tracking technique using relative displacements of gravity points of cross sectional images of blood vessels was proposed to guide the ultrasound focus in the liver which moves with respiration. Experiments with healthy volunteer livers demonstrated that the average error of the target position estimation was within 3mm. The error was less than 4mm even with a position prediction process for considering time delay between the time points of position estimation and transducer setup. These results suggested that the proposed technique was sufficient for guiding the focus and hence the imaging slab position and orientation for the "self-reference" thermometry.

1230. Temperature Monitoring with MURPS in a Reduced Field-Of-View Mohammed Hassan Aljallad1, 2, Jing Yuan3, Magda Pilato3, Lawrence Patrick Panych3 1University of Massachusetts Lowell, Lowell, Massachusetts, USA; 2Brigham and Women's Hospital, Boston, Massachusetts, USA; 3Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA

MURPS was implemented for reduced field-of-view (rFOV) imaging using 2D RF excitation so that no additional time would be needed to acquire three MURPS slices compared to the time to acquire a single, full field-of-view slice without MURPS.

1231. Auto-Tracking Self-Reference Temperature Mapping During HIFU Transmission: Ex-Vivo Experiments and Motion Simulations Yu-Shun Wang1, Teng-Yi Huang1, Chih-Ching Wu2, 3, Hsu-Hsia Peng2, Wen-Shiang Chen, 34, Wen-Yih Isaac Tseng5 1National Taiwan University of Science and Technology, Taipei, Taiwan; 2National Taiwan University, Taipei, Taiwan; 3National Health Research Institutes, Taipei, Taiwan; 4National Taiwan University Hospital, Taipei, Taiwan; 5Medical College of National Taiwan University, Taipei, Taiwan

MR temperature mapping by proton resonance frequency (PRF) shift has been shown useful to monitor the treatment process of high-intensity- focused-ultrasound (HIFU) thermotherapy. However, the conventional reference subtraction method for temperature mapping has one major drawback. The accuracy of temperature mapping may be affected by tissue movement (e.g. respiration). To solve this problem, we proposed an alternative method which tracked the heating region automatically and estimated its background phase by applying 2D polynomial fitting. In this study, the proposed method was applied on ex-vivo porcine liver experiments. Moreover, simulated motion was added into the acquired image to test the efficiency of our method. The result shows our method is a robust and reliable method for temperature monitoring.

1232. Analysis and Optimization of the IR-GRE Delayed Enhancement MRI Sequence Used for Imaging Post RF Ablation Scars in the Posterior Wall of the Left Atrium Sathya Vijayakumar1, 2, Eugene Gennaidy Kholmovski1, Nassir Marrousche1, Edward DiBella1 1University of Utah, Salt Lake City, USA

Radio Frequency (RF) ablation of posterior wall of the left atrium (LA) has become an accepted form of treatment for atrial fibrillations. Recently Delayed Enhancement MRI (DE-MRI) using an Inversion Recovery 3D Gradient Echo (IR-GRE) sequence has been proposed to visualize and assess the extent of post RF ablation scars in the LA. In this study, we analyze the performance of this sequence with respect to flip angles, inversion times and image contrast. The importance of phase images to distinguish scar and fat is also established.

1233. Improved Precision of MR Temperature Mapping of Mobile Organs Using Magnetic Field Modeling Gregory Maclair1, 2, Baudouin Denis de Senneville1, Mario Ries1, Bruno Quesson1, Pascal Desbarats2, Jenny Benois-Pineau2, Chrit Moonen1 1Laboratory for Molecular and Functional Imaging, Bordeaux, France; 2LaBRI, Talence, France

Real-time thermometry provides real-time temperature monitoring inside the human body and is an interesting tool to control interventional therapies based on thermal ablation. The PRF technique gives an estimate of temperature change at instant t by evaluating phase shifts between dynamically acquired images and reference data sets. The proposed approach for MR-thermometry consists in modeling the contribution of phase changes induced by respiratory motion in the abdomen during a learning step by assuming that demagnetization field changes can be approximated in first order with a linear term. Subsequently, during the intervention, the necessary phase reference maps are calculated in real-time.

1234. Combining 2D RF Excitation, Parallel Imaging and UNFOLD in Focused Ultrasound Heating Experiment Chang-Sheng Mei1, 2, J. Yuan2, B. Madore2, N. McDannold2, L. P. Panych2 1Boston College, Chestnut Hill, Massachusetts, USA; 2Harvard Medical School, Brigham and Women's Hospital, Boston, Massachusetts, USA

In many clinical MRI-Guided Focused Ultrasound procedures, the focus is often much smaller than FOV. In addition, for acoustic wave to transfer to the ROI, there must be water in between the sonication source and the heated subject, resulting in even larger FOV and more scan time imaging unwanted region. To improve temporal resolution, we use technique that combines three different approaches at fast imaging: parallel imaging, UNFOLD and 2D RF excitation [3]. Results are shown in phase images where the FOV was fitted to a heated target, the FUS focus region, allowing temporal resolution to be increased by 8 fold.

1235. A New Spectrum-Based Model for MR Thermometry Xinyi Pan1, Cheng Li1, Kui Ying1 1Tsinghua University, Beijing, People's Republic of China

In this work, a novel spectrum based model is proposed for MR PRF thermometry. The new model describes the signal under temperature change accurately and can be solved by using a modern spectrum analysis algorithm ¨C the extended Prony method, which offers a good spectral resolution compared to conventional FFT analysis. With this model, the absolute temperature map can be obtained using a multi-echo GRE sequence without suffering from the disturbances caused by the fat component, inter-view motion and field drift. The results of phantom experiment are quite consistent with the real temperature measurement by the thermocouple probe.

Poster Sessions

224

1236. Absolute Temperature Imaging with Non-Linear Fat/Water Signal Fitting Kevin Michael Johnson1, Venkata Chebrolu1, Scott B. Reeder1 1University of Wisconsin - Madison, Madison, Wisconsin, USA

Previous work has shown improved absolute temperature mapping using fat as an internal reference in spectroscopic imaging in tissues that contain both water and fat. We propose a rapid method signal model based method for fat-water temperature mapping, capable of producing absolute temperature images with far fewer time points than spectroscopic method. Evaluations in a fat/water phantom show excellent agreement with measurements made using a temperature probe.

1237. Rapid MR Temperature Imaging Based on Model-Predictive Filtering of Undersampled Data Nick Todd1, Ran Niu, Mikhail Skliar, Dennis L. Parker 1University of Utah, Salt Lake City, Utah, USA

Thermal therapies under MR guidance would benefit from an acceleration in the rate at which MR temperature maps are acquired. For procedures that induce rapid tissue heating, current MR techniques to monitor temperature cannot simultaneously provide adequate temporal resolution, spatial resolution and FOV coverage. We present an algorithm that combines thermal model predictions with undersampled k-space data to reconstruct accurate temperature maps. When applied to proton resonance frequency (PRF) data, accurate temperature maps are created using one-sixth of the full measurement data. Reducing the number of acquired k-space lines allows for faster scan times, greater volume coverage or higher spatial resolution.

1238. Cramer-Rao Lower Bound for Model-Based PRF Temperature Mapping Cheng Li1, Xinyi Pan1, Kui Ying1 1Tsinghua University, Beijing, People's Republic of China

In this work, the expression for Cram¨¦r-Rao Lower Bound (CRLB) for model based PRF Temperature mapping is derived by exploiting the characteristic that the temperature estimation intrinsically is a frequency difference estimation of damped complex exponential signal. With the CRLB, the noise performance of two algorithms to estimate the temperature, Prony algorithm and LM algorithm based on ML criterion, is evaluated and compared. By investigating the CRLB dependence on the imaging SNR, number of echoes, echo times, fat/water ratio, the choice of imaging parameters is discussed. The CRLB analysis theoretically provides insight into how the imaging parameters and estimation algorithm affect the noise performance in temperature mapping.

1239. Preclinical Testing of a Second-Generation MRI-Guided Focused Ultrasound System for Transcranial Brain Tumor Ablation Nathan McDannold1, Eyal Zadicario2, Magdalini Pilatou1, Ferenc Jolesz1 1Harvard Medical School and Brigham and Women's Hospital, Boston, Massachusetts, USA; 2InSightec, Haifa, Israel

This work tested the performance of a second-generation focused ultrasound device developed for noninvasive thermal ablation of brain tumors. Tests were performed using cadaver skulls and tissue-mimicking phantoms. MRI-based thermometry was used to evalu-ate the focal heating during high-power sonications (for ablation), lower power sonications (to verify the focal point localization), and heating adjacent to the skull bone. The device, which uses cavitation-enhanced heating, expanded the range of targetable regions in the brain and increased the ratio between focal heating and skull-induced heating. This ratio was 15.6±5.6 when cavitation was evident and 1.6±0.8 when it was not.

1240. MR Acoustic Radiation Force Imaging: Comparison of Encoding Gradients Jing Chen1, 2, Ron Watkins1, Kim Butts Pauly1 1Stanford University, Stanford, California , USA

MR acoustic radiation force imaging (MR-ARFI) is a novel method toguide HIFU interventions. It measures the tissue displacement inducedby the acoustic radiation force, which is most suitable forapplications with little temperature elevation. In this work, threedifferent gradient sets for displacement encoding are implemented andcompared for MR-ARFI. By using the repeated bipolar gradients, thenonlinear background phase was reduced, and the SNR was significantlyenhanced. Displacement on the order of submicrons could be detectedwith the improved encoding gradients.

1241. Monitoring of HIFU Treatment Effectiveness by MR Imaging: Advantage of the Magnetization Transfer Ratio Over the Thermal Dose as Evidenced by Overheating Experiments Hsu-Hsia Peng1, Teng-Yi Huang2, Hsiao-Wen Chung1, Chih-Ching Wu1, Wen-Shiang Chen3, Wen-Yih Isaac Tseng4 1National Taiwan University, Taipei, Taiwan; 2National Taiwan University of Science and Technology, Taipei, Taiwan; 3National Taiwan University Hospital, Taipei, Taiwan; 4Medical College of National Taiwan University, Taipei, Taiwan

We performed a deliberately designed overheating HIFU treatment experiment where tissues were heated over 100 °C, to investigate the use of the magnetization transfer ratio (MTR) for evaluation of treatment extent in the presence of boiling-induced air bubbles and the consequent susceptibility artifacts. The thermal dose as conventionally used to estimate cell damage failed to outline the heated areas reliably, whereas the MTR measured after termination of HIFU treatment correctly indicate the heated extents. Geometrical consistency between MTR maps and optical images of the heated spot suggests the importance of simultaneous measurements of temperature and MTR changes for HIFU heating.

1242. Acute and Chronic Magnetization Transfer Ratio Observations in Canine Cryoablation Andrew B. Holbrook1, 2, Sonal Josan1, Donna M. Bouley1, Bruce Daniel1, Kim Butts Pauly1 1Stanford University, Stanford, California , USA

MR-guided cryoablation is a promising minimally invasive treatment of prostate cancer. However, it is not clear what images acquired after ablation provide in terms of tissue assessment. Besides contrast-enhanced (CE) imaging, magnetization transfer (MT) imaging is a potential way of assessing tissue in-vivo. Cryolesions were created in three canines, each imaged three times over 2-3 weeks with MT and CE protocols before being euthanized for histological analysis. MT contrast could be seen immediately and persisted throughout the chronic experiment, even as hemorrhage decreased and the lesions changed. MT contrast could complement CE imaging for assessing the prostate as it heals.

Poster Sessions

225

1243. MRI-Guided Cryoablation - Acute Cryolesion Assessment with T1, T2 Imaging Sonal Josan1, Maurice van den Bosch1, Jarrett Rosenberg1, Bruce Daniel1, Kim Butts Pauly1 1Stanford University, Stanford, California , USA

MRI guided cryoablation is a promising minimally invasive therapy for prostate tumors. Contrast enhanced(CE), DWI and MT images can be used to predict the extent of tissue necrosis. The purpose of this work was to evaluate the appearance of the acute canine prostate cryolesion on conventional T1 and T2 weighted images, and compare those to the CE images. The signal enhancement on T2w images was correlated to the freeze area, and the lesion boundaries on T1 and T2 images were compared to the CE lesion.

B1 Mapping & Correction Hall D Thursday 13:30-15:30

1244. Radiofrequency (B1) Field Mapping in the Heart and Lungs Using a HASTE Double Angle Method Kelvin Chow1, Ian Paterson1, Richard Thompson1 1University of Alberta, Edmonton, Canada

The double angle method for mapping radiofrequency (B1) fields was adapted for use in the heart and lungs using the HASTE pulse sequence and free breathing acquisition. At 1.5T, significant heterogeneity was found within the chest, with flip angle variations >20 between the right and left heart, as well as ~10 between the base and apex. The right lung experiences an average flip angle ~20 less than the left lung, with the largest spatial gradients around the heart. The HASTE approach to mapping B1 fields is applicable to other regions and higher field strengths (with minor modifications).

1245. Adiabatic B1 Mapping for RF Current Density Imaging Kim Shultz1, Greig Scott1, John Pauly1 1Stanford University, Stanford, California , USA

RF current density imaging, useful for ablation treatment planning and RF safety evaluation, requires mapping a large range of B1 magnitudes in the presence of strong off-resonance effects. Standard B1 mapping methods like the double angle method require many repetitions to achieve the necessary dynamic range and lose accuracy in B1 phase measurement as off-resonance effects increase. An adiabatic excitation that is not brought fully to on-resonance creates transverse magnetization approximately linearly dependent on B1 magnitude over a large range of B1 values. Off-resonance effects can be corrected using a second excitation with a negative frequency offset.

1246. B1 Correction Using Double Angle Look-Locker (DALL) Trevor Wade1, 2, Brian Rutt1 1Robarts Research Institute, London, Canada; 2University of Western Ontario, London, Canada

A new method for B1 mapping is introduced that takes advantage of fast 3D imaging at low flip angles. By sampling the inversion recovery curve using two different, small tip angle RF pulses, an expression is obtained for both a corrected T1 and the achieved flip angle. This results in a B1 mapping technique that is very fast and efficient at low flip angles and does not require long TR values.

1247. B1 Mapping of Coil Arrays for Parallel Transmission Hans-Peter Fautz1, Mika Vogel1, Patrick Gross1, Adam Kerr2, Yudong Zhu3 1GE Global Research, Garching, Germany; 2Stanford University, Stanford, California , USA; 3GE Global Research, Niskayuna, New York, USA

A composite technique for B1 mapping of transmit coil arrays is proposed that uses all coil elements for signal excitation whereas the flip angle produced by the individual coils is encoded using a magnetization preparation. Only one flip angle encoding scan is required per coil element plus one reference scan that is used for the calibration of all coils. The dynamic range of the excitation pulse of the imaging part is reduced over the FOV allowing a significant increase in precision with which low B1 field amplitudes from single coils can be determined.

1248. Simultaneous Measurement of B0- And B1-Maps with Modified Actual Flip Angle Imaging Sequence Alexis Amadon1, Nicolas Boulant2 1CEA-Saclay, Gif-sur-Yvette, France; 2Siemens Medical Solutions, Saint-Denis, France

In high-field MRI, more and more sequences make use of the prior knowledge of B0- and B1-maps of the object under study. This abstract describes a fast method to simultaneously measure 3D maps of the B0 and B1 fields. Examples of brain maps acquired with this method are given at 3T.

1249. Rapid Proton Density Weighted Abdominal MRI at 3 Tesla with RF Non-Uniformity Correction Houchun Harry Hu1, Kyunghyun Sung1, Krishna S. Nayak1 1University of Southern California, Los Angeles, California , USA

A retrospective approach to compensate variations in signal intensity due to RF transmit and receive inhomogeneity is described for proton-density-weighted abdominal imaging. The model utilizes rapid, low-resolution acquisitions to measure the RF transmit and receive fields. Corrections for RF-induced signal shading are not only helpful in improving image quality, but are essential in applications requiring signal-intensity-based quantification. We hypothesize that this method can accurately remove signal intensity non-uniformity typically encountered in multi-coil abdominal imaging, and demonstrate its performance at 3 Tesla. Signal non-uniformity was reduced from 46% to 4% and 25% to 15% in phantom and in vivo experiments, respectively.

Poster Sessions

226

B0 Inhomogeneity Correction (Global/Local) Hall D Monday 14:00-16:00

1250. Multiple Resonant Frequency Offset Acquisitions for Imaging of Metallic Implants Kevin M. Koch1, R F. Busse2, T A. Lewein1, H G. Potter3, R S. Hinks1, K F. King1 1GE Healthcare, Waukesha, Wisconsin, USA; 2GE Healthcare, Madison, Wisconsin, USA; 3Hospital for Special Surgery, New York, New York, USA

Most metallic implants used in bone and joint arthroplasty induce severe spatial perturbations to the B0 magnetic field utilized in MR. These perturbations distort slice-selection and frequency encoding techniques utilized in conventional 2D MR imaging and tremendously hinder MR diagnosis of complications from arthroplasty. A method is presented whereby multiple 3D fast-spin-echo images are collected using discrete offsets in RF transmission and reception frequency. It is demonstrated that these images can be combined into a composite image that is devoid of slice-plane distortion and possesses greatly reduced distortions in the readout direction, even in the immediate vicinity of metallic implants.

1251. Dynamic Compensation of B0 Field Inhomogeneities Restores Complex FMRI Time Series Activation Power Andrew David Hahn1, Andrew S. Nencka1, Daniel B. Rowe1 1Medical College of Wisconsin, Milwaukee, USA

Fluctuations in the main magnetic field (B0) often occur during fMRI experiments as a result of subject respiration or motion. The effect is temporal noise in both the magnitude and phase, which can reduce the significance of statistical tests for functional activity. If a single image in a time series is chosen as a reference, all other images in the series can be corrected using their inherent phase information such that the B0 field offset at each acquisition point is time invariant. This reduces or removes effects of temporal variations in B0 homogeneity, providing higher quality fMRI time series.

1252. Towards Parcellated Dynamic Shimming Michael Poole1, Richard Bowtell1 1University of Nottingham, Nottigham, UK

The need for a homogeneous magnetic field in MRI is well established, especially at high static magnetic field strengths where susceptibility-induced image distortions and signal losses become excessively large. Dynamic shim updating has been shown to improve magnetic field homogeneity to a greater extent than conventional whole volume shimming. Previous work showed by simulation that the magnetic field inhomogeneity can be further reduced if shimming is performed over a series of compact, cuboidal sub-volumes. In this work we corroborate the simulated results with experimental data obtained at 7T and demonstrate a fast, robust automatic field mapping and shim calculation routine.

1253. Dynamic B0 Shimming in the Heart at 3T Jeff A. Stainsby1, Venkat Ramanan2, Graham A. Wright2 1GE Healthcare, Toronto, Canada; 2Sunnybrook Health Sciences Centre, Toronto, Canada

Dynamic shim updating has been recently demonstrated to provide benefit in neuro applications. This study investigates the feasibility of performing dynamic shim updates as a function of both spatial location and cardiac phase in cardiac imaging at 3T. Dynamic shim updating was shown to reduce the mean frequency offset across multiple slices and cardiac phases from 28.5Hz to 2.3Hz and in-plane linear field variations from –3.35 and 3.05Hz/cm to –0.19 and 1.15Hz/cm respectively.

1254. Sense Shimming (Sensh); a Fast Approach for Determing Field Inhomogeneities Using Coil Sensitivity Information Daniel Nicolas Splitthoff1, Maxim Zaitsev1 1University Hospital Freiburg, Freiburg, Germany

The pursuit for ever higher field strengths and faster data acquisitions has led to the construction of coil-arrays with high numbers of elements. With the SENSE approach, it has been shown by Pruessmann et al., how the sensitivity of those elements can be used for image encoding. We will here present a proof of principle of a method which can be considered a special case of the SENSE method and completely abstains from using encoding gradients. The FID data thus obtained can be used for determining field inhomogeneities; the method has therefore been termed SENSH for SENsitivity Shimming.

1255. Dependence of the View-Angle-Tilting Technique on the Slice Orientation Angle in Correcting Susceptibility Artifacts Kwan-Jin Jung1, 2, Chan-Hong Moon2, Hua Peng1 1Univ. of Pittsburgh & Carnegie Mellon Univ., Pittsburgh, Pennsylvania, USA; 2University of Pittsburgh, Pittsburgh, Pennsylvania, USA

The view-angle-tilting (VAT) technique has been known to be effective in correcting the susceptibility artifacts in slice selective MR imaging. However, it has been discovered that VAT works only when the slice orientation is orthogonal to the longer axis of the object with susceptibility. This discovery has been theoretically analyzed and confirmed by computer simulation and experimentation at 3T on a phantom and a human head.

1256. Correction of Susceptibility Artifacts in Slice Selective MR Imaging at a Specific Slice Orientation Angle Kwan-Jin Jung1, 2, Chan-Hong Moon2 1Univ. of Pittsburgh & Carnegie Mellon Univ., Pittsburgh, Pennsylvania, USA; 2University of Pittsburgh, Pittsburgh, Pennsylvania, USA

The effects of susceptibility in slice selective MR imaging include slice offset in the slice direction, and the readout shift in the readout direction. When the projection of the slice offset onto the readout axis has the same length as the readout shift but with an opposite polarity, the geometric shift is corrected on the reconstructed image. This correction condition is met when the slice orientation is made oblique to the longer axis of the object with susceptibility by an angle of arctan(GS/GR). This discovery has been theoretically analyzed and confirmed by a computer simulation and experiments at 3T on a phantom and a human head.

Poster Sessions

227

1257. Inhomogeneity Correction at 7 Tesla Using Masked Mean Filtering of Fast and Low Resolution Gradient Echo Reference Data Michael Schildt1, 2, Kai Zhong2, Klaus Dietz Tönnies2, Oliver Speck2 1Leibniz-Institute for Neurobiology, Magdeburg, Germany; 2"Otto von Guericke" University, Magdeburg, Germany

High resolution and high contrast T1 images are widely used as anatomical reference for functional imaging studies. The anatomical information is obtained from 3D gradient echo data (e.g. MPRAGE). Typically, images acquired at high field strength of 7 Tesla suffer from severe B1 inhomogeneity resulting in erroneous segmentation due to strong intensity variation of voxels representing similar tissue (e.g. brain gray or white matter). In this study fast and low resolution gradient echo reference data with minimal intrinsic contrast are used to estimate the B1 inhomogeneity by masked mean filtering and correspondingly correct the MPRAGE intensity variation.

1258. Reduction of Artifacts in Susceptibility Weighted Imaging Zhaoyang Jin1, 2, Ling Xia2, Yiping Peter Du3 1Hangzhou Dianzi University, Hangzhou, People's Republic of China; 2Zhejiang University, Hangzhou, People's Republic of China; 3University of Colorado Denver School of Medicine, Denver, Colorado , USA

In susceptibility weighted imaging, sub-optimal selection of the size of low-pass filter results in large residual background phase in the phase mask in regions with severe field inhomogeneity and artifacts in the susceptibility weighted images. The minimum-intensity projection (mIP) can also cause signal loss in peripheral regions of the brain. In this study, we demonstrate the dependency of the severity of artifacts in the phase mask on the size low-pass filter. We also present a volume-segmented mIP approach to eliminate the signal drop-off in peripheral region of the brain.

Parallel Imaging Hall D Tuesday 13:30-15:30

1259. A Variable Projection Method to JSENSE Leslie Ying1, Jinhua Sheng1 1University of Wisconsin - Milwaukee, Milwaukee, Wisconsin, USA

JSENSE formulates parallel imaging as a nonlinear problem to estimate the coil sensitivities and the desired images simultaneously. The existing algorithm solves the problem by iterative alternating minimization, which requires quite a few self calibration data for an accurate initial sensitivity estimation. In this abstract, we propose to use variable projection method to solve the nonlinear optimization problem. This method requires very few self calibration data because it converges to an optimal solution regardless of the initial value. The proposed method has been tested on a set of simulation data and demonstrated promising results.

1260. Automatic Coil Selection for SENSE Imaging with Large Coil Arrays Mariya Doneva1, Peter Börnert2 1University of Luebeck, Luebeck, Germany; 2Philips Research Europe, Hamburg, Germany

The use of a large number of coil elements for parallel imaging allows improved imaging performance and increased SNR but can lead to memory storage problems and increased reconstruction times. We present an efficient approach for coil selection, based on singular value decomposition (SVD), applicable to massively parallel SENSE imaging. The SVD-based coil selection can be used instead of manual coil selection in conventional scan planning and is especially useful in planning double oblique SENSE scans. It is also applicable to real-time or interventional imaging, where the selection could be performed locally enabling dynamical coil switch during image acquisition.

1261. A Comparison of Reconstruction Techniques for Non-Uniformly Sampled 3D Parallel Imaging Zhikui Xiao1, 2, William Scott Hoge2, R. V. Mulkern, 23, Guangshu Hu1, Walid E. Kyriakos2, 3 1Tsinghua University, Beijing, People's Republic of China; 2Brigham and Women's Hospital, Boston, Massachusetts, USA; 3Children's Hospital, Boston, Massachusetts, USA

In this abstract, we explore a specific non-uniform sampling scheme for 3D imaging on a rectilinear grid. We show that high-quality images can be reconstructed by 2D-SPACE RIP and 2D-GRAPPA-Operator. To evaluate the proposed sampling method and reconstruction schemes, results from a phantom study and in-vivo 3D human data are shown. Overall, fewer artifacts can be seen in the 2D-SPACE RIP reconstructions.

1262. Accelerating Acquisition in Spiral Imaging Ajit Devaraj1, Jim Pipe1 1St. Joseph's Hospital and Medical Center, Phoenix, Arizona , USA

Most present day 3D imaging techniques are based on non-cartesian trajectories to help traverse k-space rapidly. The ever increasing demand for reduced scan time makes non-cartesian parallel imaging necessary. However non-cartesian parallel imaging is computation intensive and algorithmically complex. PILS-like algorithms provide a good compromise between potential acceleration factors and the complexity introduced in reconstruction. Presented here is a PILS inspired algorithm for multi-coil reconstruction of spiral data acquired with a bird-cage coil geometry.

1263. Parallel Image Reconstruction Using a Single Signal and PSFT Anti-Alias Image Reconstruction Satoshi Ito1, Yoshifumi Yamada1 1Utsunomiya University, Utsunomiya, Japan

Sensitivity encoding (SENSE) accelerate MR scan time by using multiple receiver coil in parallel scan time. Here, we propose a method to reconstruct under-sampled images using only a single set of signals. The signal obtained in the phase-scrambling Fourier Transform imaging (PSFT) can be transformed into the signal described by the Fresnel transform of the objects, in which alias-free images can be obtained by optionally scaling the object images to fit in the field-of-view (FOV). By applying a weighting function to the alias-free image corresponding to sensitivity of the receiver coil and then calculating a weighted PSFT signal from the weighted alias-free images, we can obtain two or more signals with different sensitivity distributions. The proposed method is demonstrated using 2-fold under-sampling with k-space trajectories.

Poster Sessions

228

1264. Non-Cartesian Parallel Reconstruction Using Null Operations (NC-PRUNO) Jian Zhang1, Chunlei Liu1, Michael Moseley1 1Stanford University, Stanford, California , USA

A new k-space based parallel reconstruction method is proposed which is called Non-Cartesian Parallel Reconstruction Using Null Operations (NC-PRUNO). This method can be used for interleaved trajectories with auto-calibration such as variable density spirals. In NC-PRUNO, all missing interleaved k-space samples are synthesized from solving a linear equation, which is formulated by applying some local null operators on all k-space locations. We also demonstrate that it can be solved efficiently and accurately with a conjugate gradient method. In comparison with other k-space methods, NC-PRUNO tries to directly estimate the missing interleaves while strictly maintaining the consistency of the acquired samples.

1265. Reconstruction of Phase Images for GRAPPA Based Susceptibility Weighted Imaging (SWI) Christian Ros1, Stephan Witoszynskyj1, Karl-Heinz Herrmann1, Jürgen R. Reichenbach1 1Friedrich-Schiller-University, Jena, Germany

Susceptibility Weighted Imaging (SWI) relies on both magnitude andphase information. Long acquisition times make SWI an interestingapplication for parallel imaging techniques, such as GRAPPA. However,the use of phased arrays requires schemes for combining images of theindividual channels. We have implemented a method that usessensitivity information from a separate measurement within the Siemens image-reconstruction framework. The results of this method were compared tothe standard Adaptive Combine reconstruction and to data obtained withthe body-coil. Images computed with our method were in good agreementwith the body-coil's data. Adaptive Combine did not only frequentlyfail to reconstruct phase images correctly, but also caused severeartifacts in magnitude images.

1266. Automatic Time Frames Subset Selection for Improved TGRAPPA Reconstruction Roger Nana1, Xiaoping Hu1 1Georgia Institute of Technology / Emory University, Atlanta, USA

In TGRAPPA, several adjacent undersampled time frames are combined to compose the data used for deriving the weights for the GRAPPA reconstruction. In this work, a method that exploits the shift invariance property of Cartesian GRAPPA is introduced to automatically select the set of time frames for the calibration that results in an optimal TGRAPPA reconstruction. This data-driven approach was demonstrated with experimental data to lead to improved performance.

1267. Smoothing Effect of Sensitivity Map on FMRI Data Using a Novel Regularized Self-Calibrated Estimation Method Yoon Chung Kim1, Jeffrey A. Fessler1, Douglas C. Noll1 1University of Michigan, Ann Arbor, Michigan, USA

In parallel imaging, sensitivity map is widely used as calibration data which plays a crucial role during the unaliasing process. Sensitivity map estimation process usually includes spatial/temporal smoothing in order to improve robustness to noise or motion artifacts. However, the effect of smoothing has not been thoroughly investigated to date. In our study, we investigate the effects of both spatial and temporal smoothing of sensitivity maps on motion corrupted fMRI data. We also propose a novel self-calibrated sensitivity map estimation technique that controls noise and smoothness via regularization.

1268. A Self-Calibration Technique for Suppression of Radial Undersampling Artifacts in Parallel Imaging Yu Li1, Feng Huang1, Randy Duensing1 1Invivo Diagnostic Imaging, Gainesville, USA

In this study, a self-calibration technique was developed to suppress the radial undersampling artifacts for parallel imaging. This technique takes advantage of an intrinsic property of radial sampling and does not need any extra calibration data. It was demonstrated that the streak artifacts can be efficiently suppressed using this method in 2D and 3D (VIPR) radial imaging.

1269. Phase Constrained Parallel Imaging for Improved Fat Suppression in Multi-Echo LC SSFP Youngkyoo Jung1, Alexey A. Samsonov1, Richard Kijowski1, Jessica L. Klaers1, Walter F. Block1 1University of Wisconsin-Madison, Madison, Wisconsin, USA

The Linear Combination SSFP (LC-SSFP) method that combines two steady-states with different passbands provides fat/water separation. However, unwanted bright fat signal is not fully suppressed. With proper phase constraints in voxels with partial voluming, the residual unwanted fat signal in water volume can be effectively removed. In this work, we demonstrate an improved SMART CG algorithm to provide parallel imaging, phase coherence, and markedly improved fat/water separation in LC SSFP images acquired with dual half-echo 3D PR trajectories. Our result demonstrates substantial image quality improvement in musculoskeletal images.

1270. A Sparse TSENSE Approach for Improved Dynamic Parallel MRI Martin Blaimer1, Felix A. Breuer1, Peter M. Jakob1, Peter Kellman2, Mark A. Griswold3 1Research Center Magnetic Resonance Bavaria (MRB), Würzburg, Germany; 2National Institutes of Health, National Heart, Lung and Blood Institute, Bethesda, USA; 3University Hospitals of Cleveland and Case Western Reserve University, Cleveland, USA

In dynamic parallel MRI improved reconstruction quality can be achieved by taking into account that signal changes occur in localized regions only. Here, a frame-work for improved TSENSE reconstructions is presented. TSENSE is based on a time-interleaved acquisition scheme and does not require a separate pre-scan for coil sensitivity estimation. Thus, robust reconstructions at high frame rates can be obtained. It is shown, that the noise enhancement due to ill-conditioning of the inverse problem is significantly reduced by considering only dynamic regions for the reconstruction process. A simple algorithm is presented for determining the dynamic regions and reducing the ill-conditioning.

Poster Sessions

229

1271. Highly Accelerated 2D GRAPPA by Randomized K-Space Sampling Clifton R. Haider1, Stephen J. Riederer1 1Mayo Clinic, Rochester, Minnesota, USA

With typical Cartesian acquisition the maximum acceleration along a single direction is more often limited by the inability to unalias the image than by the noise amplification. Because acceleration techniques are generally more robust when performed along two vs. one direction, the initial implementation of random sampling GRAPPA studied uses 2D acceleration. Further, a Gaussian distribution is applied to differentially weight the sampling of the lower spatial frequencies to improve image quality. We show experimental studies done in phantoms using eight coils with net acceleration factors, including the autocalibration region, of 4 and 8.

1272. Parallel Image Reconstruction Using a Single Signal in Phase-Scrambling Fourier Imaging Technique Satoshi Ito1, Yoshifumi Yamada1 1Utsunomiya University, Utsunomiya, Japan

A novel image reconstruction technique is proposed in which parallel image reconstruction is performed based on the SENSE algorithm using only a single set of signals. The signal obtained in the phase-scrambling Fourier transform imaging technique can be transformed to the signal described by the Fresnel transform of the objects, which is known as the equation of diffracted wave-front equation of the object in acoustics or optics. The application of a weighting function to the PSFT signals has a similar effect as the application of a sensitivity function to the object function itself. Therefore, we can obtain two or more folded images from a single set of signals, and image reconstruction based on the SENSE algorithm is possible using a series of folded images given different weighting functions.

1273. Variable Density Sampling in Radial K-T GRAPPA Jingsi Xie1, Feng Huang2, Kui Ying3, Debiao Li1 1Northwestern University, Chicago, Illinois, USA; 2Invivo Corporation, Gainesville, USA; 3Tsinghua University, Beijing, People's Republic of China

Radial GRAPPA and radial k-t GRAPPA have been proposed in radial imaging. But they need extrally acquired or calculated full k-space data, which require more reconstruction time. In this abstract, we show that variable density sampling is applicable in radial k-t GRAPPA, which avoids the extra acquisition or calculation of calibration signal.

1274. Channel Compression for BLADE Alto Stemmer1, Vladimir Jellus1, Stephan Kannengiesser1, Berthold Kiefer1 1Siemens Medical Solutions, Erlangen, Germany

Novel multi-channel coils with 32 or more elements allow shorter scan times due to improved signal to noise ratios and higher parallel imaging performance. Increased reconstruction times for advanced imaging techniques such as BLADE can, however, be a problem in routine clinical imaging. In this work, we show that the reconstruction times can be reduced by introducing channel compression techniques at various points in the BLADE reconstruction pipeline.

1275. Phase-Constrained Reconstruction of GRAPPA for Accelerated MR Acquisitions Mohammad Sabati1, 2, Haidong Peng1, 2, Richard Frayne1, 2 1University of Calgary, Calgary, Canada; 2Calgary Health Region, Calgary, Canada

Scan time reduction is important in clinical MR imaging. Partial Fourier acquisitions rely on the conjugate symmetry of Hermitian data and allow for shorter scan times with fewer phase-encoding steps. A further scan time reduction has been achieved by combining partial k-space acquisitions with parallel imaging. In this study, we propose a combined GRAPPA+POCS (GRAPOCS) technique that allows simple and efficient inclusion of phase- and data-consistency constraints in reconstruction to improve image quality and to achieve higher acceleration factors. We evaluate the performance of this method using phantom and human data.

1276. GRAPPA-POCSENSE Eugene G. Kholmovski1 1University of Utah, Salt Lake City, USA

GRAPPA is a widely used technique for parallel MRI. The technique usually has sub-optimal SNR and residual aliasing in comparison with SENSE. One of the main causes for the GRAPPA sub-optimality is an inconsistency between individual coil images which reconstructed independently one from the others. POCSENSE is an iterative technique for parallel MRI that enforces consistency between individual coil images and allows incorporation of various constraints to improve resulting image quality. GRAPPA and POCSENSE can be readily combined to utilize strong points of both methods for improved parallel MRI reconstruction.

1277. An Approach to Coil Calibration Based on Prior Training Data Francesco Padormo1, Rita G. Nunes1, David Atkinson2, Philip G. Batchelor, Jo V. Hajnal1, David J. Larkman1 1Hammersmith Hospital, Imperial College London, London, UK; 2University College London, UK

Calibration of coil sensitivities is an intrinsic part of the MR exam. Calibration is used for parallel imaging or to correct signal modulations due to local coils. As coils become smaller, higher resolution images are needed for calibration and scan times increase. Parallel transmit further increases the time taken to calibrate as both the transmit (B1) and receive fields are required. This work explores the variation in receive coil sensitivities across a population and using this to construct a model of coil sensitivity which could be used to reconstruct unknown coil sensitivities, reducing or removing the need for individual calibration.

Poster Sessions

230

1278. Improved Spatial Homogeneity and Sensitivity Estimation for Multi-Coil Image Reconstruction Tolga Çukur1, Dwight Georger Nishimura1 1Stanford University, Stanford, California , USA

Receiver arrays composed of surface coils generally yield non-uniform coverage over the spatial extent of the array. If the coil sensitivities are exactly known, then this non-uniformity can be corrected for in the reconstruction step. However, accurate sensitivity information is usually not available. For most applications, either a sum-of-squares (SOS) reconstruction is performed or an SOS normalization is used to estimate the sensitivities. Nevertheless, the SOS combination usually yields intensity modulations. A pth-norm combination that achieves a flatter profile can instead be employed to improve the sensitivity estimates. Both multi-coil image combination and self-calibrated parallel imaging applications are shown to benefit from the proposed method.

1279. The Impact of Parallel Imaging Reconstruction on Image Phase: Implications for Phase-Sensitive Imaging Anja C.S. Brau1, Philip J. Beatty1, Charles A. McKenzie2, Huanzhou Yu1, Ann Shimakawa1, Scott B. Reeder3, Jean H. Brittain4 1GE Healthcare, Menlo Park, California , USA; 2University of Western Ontario, London, Canada; 3University of Wisconsin, Madison, Wisconsin, USA; 4GE Healthcare, Madison, Wisconsin, USA

This work examines the impact of parallel imaging reconstruction on image phase to identify possible sources of phase perturbation. The phase effects of SENSE and ARC reconstruction are compared in the context of multi-point phase-sensitive imaging. It is shown that when the unaliasing step is separated from the coil combination step, for example in coil-by-coil reconstructions, original image phase is unperturbed. This finding has implications for the design of parallel imaging calibration strategies for phase-sensitive imaging.

1280. Phase-Preserving Multi-Coil Combination with Improved Intensity Modulation Rexford David Newbould1, Stefan Skare1, Roland Bammer1 1Stanford University, Stanford, California , USA

Each coil image in a phased array contains a different phase offset, due to the coil's geometry, wiring, receiver delays, and electrical properties under varied loads. Coil images are usually combined using the magnitude sum-of-squares (SoS) operation, due to its ease and no a priori coil knowledge required. However, the SoS discards phase information, used in a number MR measurements, and exacerbates image intensity variation from the coil sensitivities which can be problematic in arrays with large numbers of small coils. A straightforward robust method for estimating coil phase offsets is presented, which can handle coils without direct signal overlap.

1281. Self-Calibrating Gridding for 3D Radial Trajectories Using GRAPPA Operator Gridding (GROG) Nicole Seiberlich1, Philipp Ehses1, Sonia Nielles-Vallespin2, Felix A. Breuer3, Martin Blaimer3, Peter M. Jakob1, 3, Mark A. Griswold4 1University of Wuerzburg, Wuerzburg, Germany; 2Siemens AG Medical Solutions, Erlangen, Germany; 3Research Center Magnetic Resonance Bavaria (MRB), Wuerzburg, Germany; 4University Hospitals of Cleveland, Cleveland, Ohio, USA

GRAPPA Operator Gridding (GROG) has been recently demonstrated as an alternative to convolution gridding. This method has a number of advantages over other gridding methods, but because it employs parallel imaging concepts to shift k-space points, a calibration dataset to determine the GROG weights is required. In two dimensional radial and spiral imaging, these weight sets can be determined by using the non-Cartesian datapoints themselves; this abstract demonstrates that an extension of this method can be used to determine GROG weights for 3D radial data. To this end, examples of an UTE dataset gridded with 3D SC-GROG are depicted.

1282. Description of Noise and Signal Probability Density Functions in SENSE Reconstructed Images Alejandro Ribes1, I-Yun Chen1, Ching-Po Lin1 1National Yang-Ming University, Taipei, Taiwan

We describe the noise and signal PDF (Probability Density Function) for images reconstructed by SENSE. We formulate a hypothesis about the shape of the PDF using the Central Limit Theorem. For checking this hypothesis we experimentally approximate the distributions by histograms and fit different PDFs to them. The results indicate that Ricean PDFs appears in signal areas of the image and Rayleigh PDFs in image areas presenting no signal. These results are useful for the future development of methods to estimate Signal-to-Noise Ratio in SENSE reconstructed images and also for image post-processing algorithms.

1283. Sensitivity Encoding of Chemical Shifts Justin P. Haldar1, Diego Hernando1, Dimitrios C. Karampinos1, Bradley P. Sutton1, John G. Georgiadis1, Zhi-Pei Liang1 1University of Illinois at Urbana-Champaign, Urbana, Illinois, USA

Conventional spectroscopic imaging experiments acquire multiple temporal encodings to enable the separation of different resonance frequencies. In this work, we explore a new kind of spectroscopic imaging that requires only a single temporal encoding, relying instead on the sensitivity encoding provided by an array of receiver coils. This provides a single-shot mechanism for chemical shift artifact correction and spectroscopic signal separation, although this comes at the expense of significant noise sensitivity.

1284. Improving Image Quality by Combining Outer Volume Supression and Parallel Imaging: Zoomed EPI with GRAPPA at 7T Robin Martin Heidemann1, Fabrizio Fasano2, Markus Vogler3, 4, Christoph Leuze1, Josef Pfeuffer4, Robert Turner1 1Max-Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; 2Fondazione Santa Lucia, Rome, Italy; 3University of Applied Sciences, Hof, Germany; 4Siemens Medical Solutions, Erlangen, Germany

The use of parallel imaging can reduce blurring due to T2* relaxation and distortions due to off-resonance effects significantly. This can also be realized with a zoomed approach, eg using outer-volume suppression (OVS). However, both methods have their limitations. Due to imperfections in the reconstruction, parallel imaging can be affected by residual foldover artifacts. On the other hand, the zoomed images can be affected by remaining signal from imperfect OVS. The combination of both methods, in this work zoomed EPI with OVS and GRAPPA, is capable to deal with both problems at once and leads to increased image quality.

Poster Sessions

231

1285. G-Factor Maps of Conjugate Gradient SENSE Reconstruction Bo Liu1, Emad Abdelsalam2, Jinhua Sheng1, Lei Ying1 1University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA; 2GE Healthcare, Waukesha, Wisconsin, USA

In parallel imaging with Cartesian sampling, the spatially varying g-factor represents the loss in signal to noise ratio (SNR) due to ill-conditioning of the matrix inverse in SENSE reconstruction. In this abstract, we propose a method to calculate the spatially varying g-factor map for conjugate gradient (CG) SENSE reconstruction with arbitrary trajectories. The method allows us to analyze how different trajectories and number of iterations in CG affect the SNR in a spatially dependent way. Our experiments show that the g-factor maps of CG SENSE increase with the number of iterations.

1286. Characterization of Artifacts and Noise Enhancement Introduced by GRAPPA Reconstructions Jonathan Rizzo Polimeni1, Graham C. Wiggins1, Lawrence L. Wald1 1MGH, Harvard Medical School, Charlestown, Massachusetts, USA

Two main sources of error---noise enhancement and image artifact---are introduced during accelerated parallel imaging. However few methods exist for characterizing the image reconstruction performance outside of the SENSE g-factor. Here we consider the noise enhancement and image artifact introduced by GRAPPA. Image artifact is quantified by validating the consistency of the GRAPPA kernel on fully-sampled data, and demonstrates an inability of the kernel to reconstruct high-frequency image features. Noise enhancement is measured through comparing image SNR between reconstructions from accelerated and unaccelerated acquisitions, and the spatial distribution of noise enhancement for GRAPPA is shown to differ substantially from the SENSE g-factor.

1287. Tikhonov Regularization: Effects on the Detection of Activations in SENSE Functional MRI Alejandro Ribes1, Cyril Poupon2, Ching-Po Lin1 1National Yang-Ming University, Taipei, Taiwan; 2Commissariat a l'Energie Atomique, Saclay, France

We apply Tikhonov regularization to the SENSE reconstruction of fMRI series. We optimise the Tikhonov regularization parameter for the detection of such activations. Results on fMRI series at reduction factor 2 are shown.

1288. A Regularization with Prior Information Technique for GRAPPA Feng Huang1, Yu Li1, George Randy Duensing1 1Invivo Corporation, Gainesville, Florida, USA

In this work, a regularized GRAPPA [2] with prior information technique is introduced. The regularization parameters are channel-wise, and are automatically determined by fitting the auto calibration signal (ACS) lines. Experimental results demonstrate that the proposed method can dramatically improve image quality, even if there is significant difference between the prior information and the target image. Moreover, the usage of low frequency prior information will not reduce the spatial resolution of the target image. The reconstruction time of conventional GRAPPA and the proposed regularized GRAPPA are almost idential.

1289. Local Mutual Information Guidied Denoising for Self-Calibrated PPI Weihong Guo1, Feng Huang2 1University of Alabama, Tuscaloosa, Alabama, USA; 2Invivo Corporation, Gainesville, Florida, USA

Local mutual information (LMI) detects the similarity of two images. It is proposed in this work that the LMI between the image reconstructed by fully acquired central k-space data and the image by GRAPPA is used to detect the noise distribution and location of the edges, and then guide the adaptive noise suppression. Experimental results show that the proposed method significantly improved SNR without reducing the high frequency information.

1290. Temporal and Noise Behavior of PEAK-GRAPPA Simon Bauer1, Matthias Honal1, Bernd Jung1, Jürgen Hennig1, Michael Markl1 1University Hospital Freiburg, Freiburg, Germany

PEAK-GRAPPA using a single uniform k-t GRAPPA is a promising tool for accelerated dynamic MR imaging. The purpose of this study was a detailed evaluation of the performance of PEAK-GRAPPA and the dependence of blurring and image quality on object dynamics. Results indicate that image quality, blurring, and noise behavior are considerably improved by PEAK-GRAPPA compared to standard methods. Noise performance demonstrated a clear dependency on object motion but was still superior to standard GRAPPA even at high object velocities.

1291. GRAPPA Navigators: Motion Correction with Parallel Imaging Paden Roder1, Jacob Willig-Onwuachi1 1Grinnell College, Grinnell, USA

The SMASH navigator method for motion correction is adapted for use with GRAPPA. Simulations comparing the SMASH and GRAPPA versions are presented and discussed.

1292. Automated GRAPPA Kernel Selection Using Akaike Information Criterion Keith Heberlein1, Roger Nana2, Stephen LaConte3, Xiaoping Hu2 1Siemens AG, Medical Solutions, Erlangen, Germany; 2Emory/GA Tech Dept. of Biomedical Engineering, Atlanta, Georgia, USA; 3Baylor College of Medicine, Department of Neuroscience, Houston, Texas, USA

GRAPPA reconstructions from parallel receivers rely on local mutual information between k-space neighbors acquired across multiple channels. Typically, the criteria for inclusion in the reconstruction kernel are based on ad hoc or empirical considerations. This work shows that the GRAPPA kernel selection can be framed as a model selection problem and that the well known Akaike Information Criterion (AIC) provides an automated and practical choice of reconstruction kernel.

Poster Sessions

232

1293. The GRAPPA Coefficients Estimation Using Weighted Least Squares Method Eugene G. Kholmovski1, Sathya Vijayakumar1 1University of Utah, Salt Lake City, USA

GRAPPA is a widely used technique for parallel MRI. Essential component of this technique is an estimation of reconstruction coefficients from auto-calibrating data. Typically, least squares (LS) method is used to solve this over-determined problem. Weighted least squares (WLS) method is valid alternative to LS. The conventional WLS is formulated with weights proportional to signal SNR. The reason why this WLS formulation is not applicable for the GRAPPA coefficients estimation and the WLS modification to address the GRAPPA problem has been studied.

1294. Iterative GRAPPA (IGRAPPA) for Dynamic Parallel Imaging Roger Nana1, Tiejun Zhao2, Keith Heberlein2, Sven Zuehlsdorff2, Renate Jerecic2, Xiaoping Hu1 1Georgia Institute of Technology / Emory University, Atlanta, USA; 2Siemens Medical Solutions, Malvern, USA

iGRAPPA is a recently introduced method in which other acquired lines in addition to the calibration lines are iteratively used to achieve an improved interpolation kernel for GRAPPA reconstruction. In this work, iGRAPPA is extended to real time non-gated non-breath-hold cardiac imaging in which the auto-calibrating lines for GRAPPA reconstruction are acquired only during the first time frame. The weights determined from the first time frame are iteratively updated based on data acquired at other frames in order to track the relative change in coil sensitivities. The effectiveness of this approach is demonstrated with in vivo data.

1295. Quantification of SNR and G-Factor for Parallel MRI: Universal Application to Image-Based and K-Space-Based Image Reconstructions Philip M. Robson1, Aaron K. Grant1, Ananth J. Madhuranthakam2, Riccardo Lattanzi1, 3, Daniel K. Sodickson4, Charles A. McKenzie5 1Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA; 2GE Healthcare, Boston, Massachusetts, USA; 3Harvard-MIT Division of Health Sciences and Technology, Boston, Massachusetts, USA; 4New York University School of Medicine, New York, New York, USA; 5University of Western Ontario, London, Canada

We demonstrate a general and robust method for the quantification of signal-to-noise-ratio (SNR) and g-factor for parallel MRI. The pseudo multiple replica SNR measurement described here allows image noise to be estimated on a pixel-by-pixel basis producing maps of SNR and g-factor that correctly represent the spatially-variant noise amplification of parallel imaging reconstruction techniques. This approach is universally applicable to any linear image reconstruction technique. We demonstrate SNR and g-factor maps for reconstructions from the same undersampled k-space data via the image-based generalized SENSE and the k-space-based GRAPPA techniques. The generality of this noise analysis method enables rigorous and quantitative comparisons between parallel imaging strategies, k-space trajectories, and image processing routines. We demonstrate SNR and g-factor maps in vivo which would have been impossible to obtain with either direct calculations or conventional multiple image replicas.

1296. Rapid Partially Parallel Reconstruction Using a Single Synthetic Target Coil Weitian Chen1, Peng Hu1, Craig H. Meyer1 1University of Virginia, Charlottesville, Virginia , USA

In GRAPPA and BOSCO, convolution operations are performed on reduced FOV k-space data from each coil and then summed to obtain a full FOV k-space data set for an individual coil. The process is repeated for each coil and the images are then combined. We propose a novel parallel imaging method that formulates the convolution process in the image domain but with dramatically reduced computational cost, particularly when a large number of coils are used. We remove the outer loop over coils by generating one unaliased data set corresponding to a synthetic “coil”. The method is demonstrated using spiral acquisitions but is applicable to more general k-space sampling methods.

1297. Analytical Computation of G-Factor Maps for Autocalibrated Parallel Imaging Philip James Beatty1, Anja C. S. Brau1 1GE Healthcare, Menlo Park, California , USA

This work describes how g-factor maps can be analytically and efficiently computed directly from the unaliasing coefficients used in autocalibrated parallel imaging. This direct approach allows the proposed method to be used with variable density and non-Cartesian acquisitions. The usefulness of g-factor maps as a tool for reconstruction parameter selection is examined in two important areas: selection of the coil combination method and selection of the reconstruction kernel size.

1298. Regularized Non-Cartesian SENSE Using a Multiscale Wavelet Model Bo Liu1, Emad Abdelsalam2, Leslie Ying1 1University of Wisconsin - Milwaukee, Milwaukee, Wisconsin, USA; 2GE Healthcare, waukesha, Wisconsin, USA

The iterative conjugate gradient method (CG-SENSE) has been widely used for non-Cartesian SENSE. However, when the reduction factor is large, the ill-conditioning problem prevents the CG-SENSE from converging to the optimal reconstruction. To address this problem, we propose a regularization technique where the regularization term is a multiscale wavelet transform. The method has the advantage that the wavelet coefficients at different wavelet scales can be weighted by different regularization parameters such that both the smooth regions and sharp edges of images can be represented accurately. The experimental results demonstrate that the proposed method improves the convergence behavior and reconstruction quality.

1299. Improved Noise Performance Using Regionally Optimized Reconstruction for Partially Parallel Imaging Yu Li1, Feng Huang1 1Invivo Diagnostic Imaging, Gainesville, USA

In this study, a regionally optimized reconstruction method for partially parallel imaging is introduced. Compared with the conventional SENSE, this method can reduce the ill-conditioning problems and improve the noise performance in the regions where g-factors are high. Compared with GRAPPA, this method minimizes the least-square error in reconstruction regionally instead of globally and hence gives better image quality in the regions where g-factors are low.

Poster Sessions

233

1300. Simultaneous Calibration Scheme for Data-Driven Parallel Imaging Reconstruction Anja C.S. Brau1, Ann Shimakawa1, Philip J. Beatty1 1GE Healthcare, Menlo Park, California , USA

This work presents a flexible calibration strategy for data-driven parallel imaging whereby multiple datasets with potentially different magnetization can be used simultaneously to train the reconstruction. Such strategies could offer improved determination of reconstruction weights when calibration data from a single dataset is limited by motion, pulse sequence, or scan time. Technical feasibility is demonstrated in volunteer studies in which calibration is performed over multiple datasets acquired with different image contrast and phase.

Parallel RF Transmission Methods Hall D Wednesday 13:30-15:30

1301. Fast Optimal Control Method for Large-Tip-Angle RF Pulse Design in Parallel Excitation William Allyn Grissom1, Dan Xu2, Jeffrey A. Fessler1, Douglas C. Noll1 1University of Michigan, Ann Arbor, USA; 2GE Healthcare, Waukesha, USA

When applied to parallel excitation, the optimal control pulse design method has some nice advantages over other methods. However, the method requires long computation times, limiting its practical use. We introduce a fast optimal control method that reduces computation time by linearizing the Bloch equation about an underlying pulse, and designs perturbations to the pulse using the linear conjugate gradient algorithm. The new method also has reduced memory requirements compared to conventional optimal control.

1302. Sparsity-Enforced Coil Array Mode Compression for Parallel Transmission Adam Charles Zelinski1, Vijayanand Alagappan2, Vivek K. Goyal1, Elfar Adalsteinsson1, 3, Lawrence L. Wald2, 3 1MIT, Cambridge, Massachusetts, USA; 2Harvard Medical School, MGH, Longwood, Massachusetts, USA; 3Harvard-MIT Division of Health Sciences & Technology, Cambridge, Massachusetts, USA

Forming linear combinations of the elements of a parallel transmission array can transform its spatial modes into a different basis set, potentially capturing TX efficiency and acceleration capabilities in a subset of the modes. Available TX channels are then applied to only a subset of array modes, those that best contribute to TX efficiency and encoding. Here we propose a target-dependent sparsity-enforced subset selection (SESS) algorithm that explicitly accounts for the desired excitation when choosing the mode subset. Brute-force search shows that SESS actually determines the best of all 12,871 possible subsets during an experiment using a 16-mode, 8-channel system.

1303. Sparsity-Enforced Joint Spiral Trajectory & RF Excitation Pulse Design Adam Charles Zelinski1, Vivek K. Goyal1, Lawrence L. Wald2, 3, Elfar Adalsteinsson1, 3 1MIT, Cambridge, Massachusetts, USA; 2Harvard Medical School, MGH, Charlestown, Massachusetts, USA; 3Harvard-MIT Division of Health Sciences & Technology, Cambridge, Massachusetts, USA

A fast sparsity-enforcement algorithm that applies to both single-channel and parallel transmission systems is proposed that generates sparse, quickly-traversable k-space trajectories & a corresponding RF excitation pulses when provided with user-defined target patterns. L1-regularization is used to tractably search over a number of possible candidate k-space trajectory segments and determine a small subset of these segments, along with an RF pulse, that best form the desired excitation. A trajectory algorithm then connects the segments in the small subset into an overall smooth trajectory. Here, we provide the method with candidate rings and generate trajectories that significantly outperform conventionally-accelerated spirals.

1304. Magnitude Least Squares Optimization for Parallel RF Excitation Design Demonstrated at 7 Tesla with 8 Channels Kawin Setsompop1, Vijayanand Alagappan2, Borjan Gagoski1, Lawrence Wald3, Elfar Adalsteinsson1 1Massachusetts Institute of Technology, Cambridge, Massachusetts, USA; 2A. A. Martinos Center for Biomedical Imaging, MGH, Charlestown, Massachusetts, USA; 3A. A. Martinos Center for Biomedical Imaging, Department of Radiology, MGH, Charlestown, Massachusetts, USA

Parallel RF excitations are often designed as a least-squares (LS) optimized approximation to a target magnitude and phase profile. However, adherence to the target phase profile is usually not important as long as the excitation phase is slowly varying compared to the voxel dimension. We describe and validate an MLS method with slice selective spoke and 4X spiral square target excitations, using an 8-channel transmit array on a 7T human MRI scanner. The method resulted in significant benefits, particularly for the spoke, where a 34% drop in root magnitude mean square error and 49% drop in RF power were observed.

1305. Slice-Selective RF Pulses for in Vivo B1+ Inhomogeneity Mitigation at 7 Tesla Using Parallell RF Excitation with a 16-Element Coil Kawin Setsompop1, Vijayanand Alagappan2, Borjan Gagoski1, Thomas Witzel2, 3, Jonathan Polimeni2, Andreas Potthast4, Ulrich Fontius5, Franz Schmitt5, Lawrence Wald, 36, Elfar Adalsteinsson1, 3 1Massachusetts Institute of Technology, Cambridge, Massachusetts, USA; 2A. A. Martinos Center for Biomedical Imaging, MGH, Charlestown, Massachusetts, USA; 3Harvard-MIT Division of Health Sciences and Technology, Cambridge, Massachusetts, USA; 4Siemens Medical Solutions, Charlestown, Massachusetts, USA; 5Siemens Medical Solutions, Erlangen, Germany; 6A. A. Martinos Center for Biomedical Imaging, Department of Radiology, MGH, Charlestown, Massachusetts, USA

At 7T, B1+ inhomogeneity for human brain imaging causes spatially inhomogeneous flip-angle with detrimental non-uniformity for both SNR and CNR. In this work we applied 8-channel parallel excitation waveforms in the low-flip-angle regime with echo-volumnar k-space trajectories that deposit slice-selective sinc “spokes” in kz, whose complex amplitudes are modulated in (kx,ky) to mitigate in-plane B1+ inhomogeneity. We designed parallel RF spoke pulses with magnitude least squares criteria, spoke location optimization, and B0 field map incorporation that demonstrated excellent B1+ mitigation for brain imaging on three human subjects at 7T.

Poster Sessions

234

1306. High-Flip-Angle Slice-Selective Parallel RF Excitation with 8 Channels at 7 Tesla Kawin Setsompop1, Vijayanand Alagappan2, Andreas Potthast3, Ulrich Fontius4, Lawrence Wald5, Elfar Adalsteinsson1 1Massachusetts Institute of Technology, Cambridge, Massachusetts, USA; 2A. A. Martinos Center for Biomedical Imaging, MGH, Charlestown, Massachusetts, USA; 3Siemens Medical Solutions, Charlestown, Massachusetts, USA; 4Siemens Medical Solutions, Erlangen, Germany; 5A. A. Martinos Center for Biomedical Imaging, Department of Radiology, MGH, Charlestown, Massachusetts, USA

At high magnetic field, B1+ inhomogeneity causes undesired non-uniformity in SNR and contrast. Parallel RF “spoke”-based designs have been shown to correct this problem and produce highly uniform in-plane magnetization with excellent slice selection with relatively short excitation durations. However, at large flip angles the excitation k-space based design method fails. Recently, several large-flip-angle excitation designs have been proposed. In this work we propose and successfully demonstrate a large-flip parallel excitation design for 90º and 180º spin-echo pulses for 8 channels at 7T in the presence of B1+ variation similar to that of human brain.

1307. In-Vivo Comparison of B1 Shimming and Spatially Tailored Parallel Excitation at 7T Vijayanand Alagappan1, 2, Kawin Setsompop3, Andreas Potthast4, Ulrich J. Fontius5, Franz Schmitt5, Elfar Adalsteinsson3, Lawrence L. Wald1 1Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, USA; 2Tufts University, Medford, Massachusetts, USA; 3MIT, Cambridge, Massachusetts, USA; 4Siemens Medical Solutions, Charlestown, USA; 5Siemens Medical Solutions, Erlangen, Germany

The inhomogeneous transmit B1 pattern in conventional volume coils at higher field strengths has motivated the development of new RF excitation strategies with multiple transmit channels. The array approach allows the transmit B1+ field inhomogeneity to be addressed by B1 shimming or by using accelerated spatially tailored 2D or 3D RF pulses. In this work we have compared the achievable flip angle homogeneity of the 2 techniques on a slice selective excitation using 8 transmit channels.

1308. RF Encoding Via Non-Linear, Iteratively Determined Encoding Functions Ulrich Katscher1, Jonathan Lisinski2, Peter Boernert1 1Philips Research Europe - Hamburg, Hamburg, Germany; 2University of Applied Sciences, Hamburg, Germany

For spatial MRI signal encoding, RF encoding via B1-gradients are an alternative to the standard Bo-gradients. RF encoding might omit all Bo-gradients, allowing for MR scanning almost free of acoustic noise. This study investigates RF encoding using non-linear encoding functions using an eight-channel transmit array for phantom imaging. Encoding functions are determined iteratively by randomized superposition of the array element sensitivities. The possibility of pure RF phase encoding (via constant B1 amplitude encoding functions) is investigated to allow future steady state-like applications. Furthermore, RF encoding was combined with 1D Fourier encoding as additional alternative for sequence acceleration.

1309. Array-Optimized Composite Excitation Pulse for Simultaneous Homogenous Excitation and Low SAR in a Human-Body Transmit-Array at 3.0T Sukhoon Oh1, Sylvie Garrett2, Christopher M. Collins1 1The Pennsylvania State University, Hershey, USA; 2The Pennsylvania State University, State College, USA

In this numerical study, an array-optimized composite RF pulse is designed to simultaneously improve the excitation homogeneity and reduce the peak SAR within the human body at 3T. The composite RF pulse can achieve both significantly better excitation homogeneity and significantly lower SAR levels than are possible with RF shimming alone.

1310. Transmit-PILS RF Pulse Design for Small-Tip-Angle Parallel Excitation William Allyn Grissom1, Jeffrey A. Fessler1, Douglas C. Noll1 1University of Michigan, Ann Arbor, USA

Existing pulse design methods for small-tip-angle parallel excitation either design pulses iteratively and can have high computational cost, or design pulses non-iteratively and are restricted to echo-planar trajectories. We introduce a method that is non-iterative and applicable to general trajectories. Compared to iterative methods, transmit-PILS achieves lower computational cost by dividing the pulse design problem for R coils into R sub-problems that are solved individually using conjugate phase pulse design.

1311. 3D RF Shimming Using Multi-Frequency Excitation Ulrich Katscher1, Holger Eggers1, Ingmar Graesslin1, Giel Mens2, Peter Boernert1 1Philips Research Europe - Hamburg, Hamburg, Germany; 2Philips Medical Systems, Best, Netherlands

For RF shimming, amplitudes and phases of a transmit RF coil array are optimized to obtain a homogeneous B1 profile. In this study, the different Tx elements are driven with different frequencies (Multi-Frequency Excitation, "MULTIFEX"). Thus, the different elements relate to different slices due to the underlying slice selection gradient. MULTIFEX enables the simultaneous excitation of different slices with different B1 profiles. It might also be used for saturation pulses, refocusing pulses, 3D RF encoding, and 3D local excitation. The study demonstrates the feasibility of MULTIFEX experimentally using a whole-body, eight-channel Tx system at 3T.

1312. Toeplitz-Based Acceleration of RF Pulse Design for Parallel Excitation Daehyun Yoon1, William A. Grissom2, Jeffrey A. Fessler2, Douglas C. Noll2 1University of Michigan, Ann Arbor, USA; 2University of Michigan, Ann Arbor, Michigan, USA

Recently, an iterative algorithm for designing the RF pulses in the spatial domain for parallel excitation using a Conjugate Gradient(CG) algorithm together with Non-Uniform FFT(NUFFT) operations was proposed. This abstract presents a method based on Toeplitz matrices to further accelerate the computation time of the aforementioned method. This method eliminates the need for interpolation and in certain circumstances, can reduce the dimensionality of the minimization problem.

Poster Sessions

235

1313. Parallel Excitation Experiments Using Measured K-Space Trajectories for Pulse Calculation Peter Ullmann1, Martin Haas2, Franciszek Hennel1, Markus Wick1, Jerôme Voiron1, Maxim Zaitsev2, Jürgen Hennig2, Wolfgang Ruhm1 1Bruker BioSpin MRI GmbH, Ettlingen, Germany; 2University Hospital Freiburg, Freiburg, Germany

Parallel Excitation has proven to be a powerful tool to reduce the typically long durations of spatially selective pulses and the resultant degradation of the excitation patterns due to off-resonance or B0-inhomogeneity effects. However, the effects of some experimental imperfections such as k-space trajectory deviations, e.g. by eddy currents, are not reduced by Parallel Excitation. In this study it is demonstrated that using measured k-space trajectories for the calculation of Parallel Excitation pulses is an effective and convenient method of reducing errors in the excitation patterns caused by such experimental imperfections of the gradient system.

1314. Automated Pulse Sequence Design for Minimal SAR in Parallel Transmission Yinan Liu1, Jim Ji1 1Texas A&M University, College Station, Texas, USA

Managing and reducing SAR is a critical issue for parallel transmission. In this work, an automated pulse sequence design method is presented to achieve minimal SAR for a given excitation pattern without extending the pulse duration. The Lagrange dual method is used to iteratively optimize the RF pulses and corresponding k-trajectory. The method is verified using computer simulations of a 4-channel parallel transmission system.

1315. Specific Absorption Rate Studies of the Parallel Transmission of Inner-Volume Selective Excitations at 7 Tesla Adam Charles Zelinski1, Leonardo M. Angelone2, Vivek K. Goyal1, Giorgio Bonmassar2, Elfar Adalsteinsson1, Lawrence L. Wald, 12 1MIT, Cambridge, Massachusetts, USA; 2MGH, Charlestown, Massachusetts, USA

SAR is a major concern in the parallel transmission (pTX) of spatially-tailored 2D and 3D excitation pulses due to E field superposition that occurs when driving multiple channels concurrently and the inefficiency of producing excitations via regional cancellation. In this work, we model average and local SAR using FDTD-simulated field data of an 8-channel pTX array and a human head model. Mean and local SAR are analyzed for 2D spiral-trajectory, inner-volume, spatially-selective RF excitation pulses as a function target flip angle, position, size, smoothness, orientation, and trajectory acceleration factor.

1316. Equiripple Design of Multidimensional RF Pulses Via Convex Optimization Daeho Lee1, Michael Lustig1, John Mark Pauly1 1Stanford University, Stanford, USA

We propose a new approach to designing RF pulses which achieves equiripple excitation profile. It formulates the RF design problem as a convex optimization problem. Thus, other physical constraints (e.g. peak RF) and regularization terms (e.g. RF power) can be easily embedded into the problem if they are represented in the form of convex functions. This approach can be extended to parallel RF transmission.

1317. Improved Accuracy of Actual Flip Angle Imaging (AFI) Kay Nehrke1, Peter Börnert1, Ulrich Katscher1 1Philips Research Europe, Hamburg, Germany

Simulations based on configuration theory have been performed to study the accuracy of the AFI technique depending on different sequence and tissue parameters. The simulation show that the spoil properties, and hence, the accuracy of the technique may be controlled by the RF spoil phase shift increment along with the diffusion sensitivity resulting from spoiling gradients. For a favorable spoil phase, moderate gradient spoiling is already sufficient to allow a good performance of the technique for a reasonable range of tissue parameters. Phantom and in-vivo experiments showed an excellent accordance with the simulations.

1318. Multidimensional Spatial Encoding by Parallel Excitation Wolfgang Ruhm1, Peter Ullmann1 1Bruker BioSpin MRI GmbH, Ettlingen, Germany

A method of MRI and spectroscopic imaging is described which allows multidimensional spatial encoding during the excitation period. It is called SPEEDI (Spatial Encoding by Excitation with Multidimensional RF Pulses) and uses multidimensional RF pulses not only for spatial modulation of the transverse magnetization magnitude, but also for generating a targeted spatial distribution of the transverse magnetization phase. Repeated excitation with different phase distributions according to a spatial encoding scheme allows measuring multidimensional images with different contrasts or spatial distributions of spectral information. SPEEDI has been implemented using Parallel Excitation and its successful experimental verification is reported.

1319. Two-Step Small Transverse Magnetization Method for the Design of 180 Spatially Selective RF Pulses Martin Haas1, Peter Ullmann2, Jürgen Hennig1, Maxim Zaitsev1 1University Hospital Freiburg, Freiburg, Germany; 2Bruker BioSpin MRI GmbH, Ettlingen, Germany

A new method for designing two-dimensional spatially selective 180° pulsesis presented, which is based on the observation that the design equation for the small tip angle regime also holds when the spin population is aligned close to both the +z and -z directions. In combination with one Bloch integration, the gap between these regimes is bridged.We demonstrate that these new pulses can perform both selective inversion and refocusing in an arbitrarily shaped target area. Similarly to transmit SENSE, STM pulses can be accelerated and RF transmit profiles of multiple coils and B0 inhomogeneities can be taken into account.

Poster Sessions

236

RF Pulse Design Hall D Thursday 13:30-15:30

1320. Improved Half RF Slice Selectivity in Presence of Eddy Currents with Quadratic Phase Saturation Sonal Josan1, 2, Elena Kaye2, John Pauly1, Bruce Daniel2, Kim Butts Pauly2 1Stanford University, Stanford, California , USA; 2Stanford University, USA

Half RF excitation pulses used in ultrashort T2 imaging are very sensitive to eddy currents which distort its slice profile. The purpose of this work is to improve slice selectivity of the half RF in the presence of eddy currents, by using quadratic phase RF saturation to suppress any out of slice magnetization, thus providing a simple robust method for accurate T2* quantitation.

1321. Fast Fat Suppression RF Pulse with Insensitivity to B1 Inhomogeneity: H-Sinc Takayuki Abe1, Takeuchi Hiroyuki1, Takahashi Tetsuhiko1 1Hitachi Medical Corporation, Kashiwa, Japan

Robust fatsat is important in clinical applications. With 1.5-T or higher MRI scanners, an adiabatic inversion pulse is used for reducing the residual fat shown on an image caused by B1 inhomogeneity. Since this pulse is a 180‹-one, a long TI is required resulting in a dead time of the measurement. So, we developed a new fast fatsat pulse called H-Sinc, which excites at a flip angle near 90‹ and is insensitive to B1 inhomogeneity. Because H-Sinc can easily induce an arbitrary FA and does not require TI, it shows faster fat suppression than that of the adiabatic inversion pulse.

1322. Improved Slice Profiles Using Low-Ripple Numerically Optimized SINC Pulses Randy Lee Tyson1, Jonathan Sharp1, Boguslaw Tomanek1 1National Research Council of Canada, Calgary, Canada

Low-ripple RF pulse design through numerical optimization using the coefficients of the discrete cosine or Fourier transform of the SINC waveform as initial parameters. Bloch simulation and optimization of waveform parameters fitted to a target slice profile results in decreased rippling in both the pass and stopbands.

1323. SLR RF Pulse Design for Arbitrarily-Shaped Excitation Profiles Joëlle Karine Barral1, John Mark Pauly1, Dwight George Nishimura1 1Stanford University, Stanford, California , USA

The Shinnar-Le Roux algorithm has been widely used to reduce the pulse design problem to a well-known finite impulse response digital filter design problem when a rectangular slice profile is desired. However, there is no intrinsic limitation to such a profile. An adaptation of the SLR algorithm is proposed, which allows the design of large flip-angle pulses producing arbitrarily-shaped excited slice profiles accurate in both, magnitude and phase. This design should benefit alternative schemes like wavelet encoding which so far suffer from magnitude and phase distortions of the excited magnetization profiles, especially when SNR-efficient large flip-angles are desired.

1324. Selective Adiabatic Refocusing Pulse Train for Nonlinear Phase Dispersion and Flip Angle Error Compensation Ziqi Sun1, Jay L. Zweier1 1The Ohio State University, Columbus, USA

A selective adiabatic full passage (AFP) pulse train, consisted of two 90 degree hyperbolic secant (HS1_R20) pulses of alternate frequency sweep (AFS) at the two ends of the pulse train, and two low power HS1_R20 AFP pulses in the middle, was developed for spin refocusing in a 3D spin echo sequence. In comparison to an amplitude-modulated refocusing pulse, AFP-AFS pulse train substantially improved signal sensitivity and uniformity, which is ascribed to the effective compensation of the nonlinear phase dispersion and flip-angle errors associated with selective AFP pulses. This interpretation is supported by the theoretical analysis and Bloch equation simulation results.

1325. Calibration Procedure of 2D RF Excitation Pulses Using Echo-Planar K-Space Trajectories Carsten Warmuth1, Robert Krieg1 1Siemens Medical Solutions, Erlangen, Germany

A temporal mismatch between gradient and RF waveforms causes strong N/2 ghosting in two-dimensional excitations when using echo-planar k-space trajectories. We implemented a quick delay calibration approach preceding each sequence using 2D RF respiratory navigators.

1326. 2D-Selective RF Excitations Based on the PROPELLER Trajectory Martin G. Busch1, 2, Jürgen Finsterbusch1, 2 1University Medical Center Hamburg-Eppendorf, Hamburg, Germany; 2Neuroimage Nord, Hamburg-Kiel-Lübeck, Germany

This work presents 2D-selective RF excitations based on the PROPELLER trajectory. The trajectory consists of segments of parallel lines which are rotated to one another. The center of k-space is covered by all segments which yields large flip angles for all segments. Profile blurring in the presence of off-resonance effects like chemical shift or magnetic field inhomogeneities is avoided by using non-selective refocusing RF pulses between the individual lines of each segment.

1327. A New Method for Single-Shot 2-D OVS Nathaniel James Powell1, Malgorzata Marjanska1, Julien Valette2, Pierre-Gilles Henry1, Michael Garwood1 1University of Minnesota, Minneapolis, USA; 2CEA-neurospin, Gif-sur-Yvette, France

Outer Volume Suppression (OVS) is sometimes needed in MR imaging and, more often, in spectroscopy. MR Spectroscopic Imaging (MRSI) studies of the brain and other anatomical regions generally require some form of OVS to ensure that the strong lipid signals from the layer of skin and subcutaneous fat do not interfere with the desired signals from deeper tissues of interest. Typically when OVS is used in brain MRSI, the standard approach involves sequentially applying multiple slice-selective (1D) suppression pulses at different angles around the periphery of the object, an approach that has drawbacks in terms of efficiency and Specific Absorption Rate (SAR). Our method employs a single two-dimensional pulse to suppress an elliptically shaped annulus in one shot, saving both time and SAR, and in some cases providing a suppression pattern that more closely matches the anatomy.

Poster Sessions

237

High Field Imaging Methods Hall D Monday 14:00-16:00

1328. Double Inversion Recovery MRI with Fat Suppression at 3T and 7T Guillaume Madelin1, Matilde Inglese1, Niels Oesingmann2 1New York University, New York, New York, USA; 2Siemens Medical Solutions USA, New York, New York, USA

Double Inversion Recovery (DIR) MRI combines two inversion pulses in order to simultaneously suppress signals from tissues with different T1 relaxation times. In the brain, DIR allows to selectively image gray matter (GM) by nulling the signal from white matter and cerebrospinal fluid at the time of the excitation pulse. Imaging GM structures is important in the study of many neurological disorders such as Alzheimer's disease, epilepsy and multiple sclerosis. This study demonstrates the feasability of 2D and 3D DIR MRI with chemical shift fat inversion recovery (csFatIR) at 3T and 7T.

1329. Comparison of BSSFP and GRE at 9.4 Tesla Joseph S. Gati1, L Martyn Klassen1, Ravi S. Menon1 1Robarts Research Institute, London, Canada

Balanced steady-state free precession (bSSFP) pulse sequences have found widespread use at clinical field strengths because of short acquisition times, unique contrast and increased signal to noise characteristics compared to similarly acquired gradient-recalled echo (GRE) methods. To date there has been no published demonstration of the advantages of bSSFP over GRE at an ultrahigh magnetic field strength that quantifies the advantages in vivo. This study performs the simple task of comparing signal to noise ratio and contrast in optimized bSSFP images versus acquisition matched GRE images in mouse brain at 9.4 T.

1330. Progress in 3d Imaging at 4 T with SWIFT Curtis Andrew Corum1, Djaudat Idiyatullin1, Steen Moeller1, Michael Garwood1 1University of Minnesota, Minneapolis, Minnesota, USA

We demonstrate high resolution T1 and proton density weighted imaging in human brain with SWIFT at 4 T. SWIFT has several unique properties. The gradient updating is very sooth so SWIFT is quieter, even than quiet radial sequences. The data can be motion corrected, similar to PROPELLER or other radial sequences, and further is immune to other common gradient based errors such as incidental phase encoding.SWIFT is 40dB quieter than equivalent fast cartesian 3d GRE imgaing sequences. We report our progress in SWIFT at 4 T for human brain imaging and look forward to developing SWIFT's potential for T1 and PD pediatric neuroimaging.

1331. High Resolution T2* Weighted Reverse and Forward Spiral Imaging at 7Tesla Peter Börnert1, Wouter M. Teeuwisse2, Holger Eggers1, Mark A. van Buchem2, Matthias JP van Osch2 1Philips Research Europe, Hamburg, Germany; 2Leiden University Medical Center, Netherlands

High resolution spiral imaging could find an interesting application in ultra-high field imaging. Reverse and long TE forward spiral imaging providing strong T2* weighting are of interest for susceptibility weighted imaging showing high anatomical detail. In this work, the basic applicability of forward and reverse spiral imaging at 7T is investigated with respect to performance, necessary corrections and contrast properties. In-vivo results are shown and discussed underlining the great potential of spiral sampling at 7T.

1332. Oh No, Where Did My Contrast Go? - Righting the Shameful Wrong About SE T1 Contrast at High Field Roland Bammer1, Anne Marie Saywer1, Jung Jiing Hsu1, Gary H. Glover1, Rexford David Newbould1 1Stanford University, Stanford, California , USA

Over the last few years concerns have been raised about lacking contrast in SE T1-weighted sequences. Specifically, 3T’s ability to provide adequate GM/WM contrast in the brain and spine was criticized. Nevertheless, it is well known that the T1 relaxation times of semi-solid tissue will increase with field strength, whereas T1 of CSF as well as T2 relaxation times remain almost unchanged across B0. Recently, it was even shown that T1 dispersion in brain tissue increases with increasing B0. T1 prolongation and dispersion actually benefit T1w imaging. The objective of this study was therefore to determine the optimal T1 contrast at 1.5T, 3T, and 7T and to find out whether or not there is truly a loss in tissue contrast with increasing B0.

1333. Optimization of HyperTSE at 7T for Efficient T2-Weighted Imaging Oliver Speck1, Matthias Weigel2 1Otto-von-Guericke-University, Magdeburg, Germany; 2University Hospital, Freiburg, Germany

The high SNR achievable at 7T can be utilized to increase the spatial resolution of morphologic T2-weighted images. However, the very high RF-power requirements can dramatically limit the efficiency of multi-spin-echo methods (TSE). HyperTSE has been proposed to reduce SAR without compromising image quality. We demonstrate that with further optimization of the RF-pulses and the flip angle variations, T2-weighted imaging at 7T with high resolution and high volume coverage is feasible without increased scan times due to SAR limitations. Without prolongation of the pulse lengths a four-fold improvement in temporal efficiency compared to a standard TSE implementation is possible.

Poster Sessions

238

Pulse Sequence Design Hall D Tuesday 13:30-15:30

1334. Control of Effective TE for 3D Fast Spin Echo – Image Quality Implications Reed F. Busse1 1GE Healthcare, Madison, Wisconsin, USA

Fast Spin Echo sequences acquire multiple echoes in a train, thus k-space is filled with echoes of varying TE. This produces signal modulation in ky-kz space, the pattern of which is determined by view order. For 3D-FSE, view ordering is highly flexible. This work introduces a number of novel view ordering strategies and explores the image quality implications of each. It is found that ordering views to produce monotonically varying TEs, with “effective TE” controlled by adjusting the echo train length produces images with the fewest artifacts and highest apparent resolution and contrast.

1335. Pulse Sequence Programming with Shared Components: An Open Source Approach Jeremy F. Magland1, Walter R.T. Witschey II2 1University of Pennsylvania Medical Center, Philadelphia, Pennsylvania, USA; 2University of Pennsylvania, Philadelphia, Pennsylvania, USA

Improvements in pulse sequence methodology as well as advances in scanner hardware continue to open new possibilities for magnetic resonance imaging. However, this growth is accompanied by increased complexity in the task of pulse sequence programming. As a result there is a growing need to share complex pulse sequences between laboratories and across institutions. Scanner incompatibilities and software complexities can hamper this kind of dissemination. Here we present a pulse sequence development paradigm that seeks to solve these problems by simplifying the pulse program implementation procedure and the act of sharing sequences between laboratories and institutions via scanner-independent, open source sequence development software.

1336. Efficient Pulse-Sequence Simulation Using Variable Subsampling and Decomposition William R. Overall1, John M. Pauly1 1Stanford University, Stanford, California , USA

A new technique for complete pulse-sequence simulation is described which takes advantage of temporal sparsity and redundancy in MR pulse sequences to greatly reduce computation time without additional a priori assumptions. Using this technique, a wide range of synthetic images can be computed in minutes. Additionally, strategies for decomposing sequence-simulation tasks in order to improve computational efficiency are described. The algorithm is implemented in a flexible, graphical simulation environment that is available online.

1337. The Optimal Acquisition Strategy for Exponential Decay Constants Estimation Roman Fleysher1, Lazar Fleysher1, Oded Gonen1 1NYU School of Medicine, New York, USA

In this report, chi^2 fitting of multi-point data is used to demonstrate that the most efficient acquisition strategy for estimating relaxation constant of (mono-) exponentially decaying signals is a two-point scheme. We also conjecture that the smallest coefficient of variation of the decay constant achievable in such experiment is 3.6 times larger than that in the image intensity obtained by averaging N acquisitions with minimal exponential weighting.

1338. Quantifying the Signal to Noise Ratio Benefit of Apodization by Sampling Density Design: A Demonstration with Sodium MRI of the Human Brain Robert Wayne Stobbe1, Christian Beaulieu1 1University of Alberta, Edmonton, Canada

For low signal applications like sodium MRI, Gibbs' ringing can degrade image quality. Apodization by sampling density design offers a significant signal to noise ratio benefit over apodization by post-acquisition filtering. This advantage is quanitifed and demonstrated with sodium imaging of the human brain.

1339. Variable Density 3D Shells Acquisition with an Increased FOV Yunhong Shu1, Matthew Bernstein1 1Mayo Clinic, Rochester, Minnesota, USA

Sometimes 3D non-Cartesian acquisitions like shells require an increased imaging FOV. To keep the spatial resolution constant, the acquisition time needs to be increased roughly as the cube of FOV, which is not acceptable for time-constrained applications. The proposed solution uses a variable density scheme which samples only the central shells more densely, while undersampling the outer shells. Here we demonstrate that variable density sampling for a 3D shells acquisition can increase the imaging FOV with less acquisition time penalty compared to a fully-sampled acquisition strategy. Previously it was shown that the undersampling artifacts are tolerable, especially for contrast-enhanced applications.

1340. Generalized Density Weighted Imaging Marcel Gutberlet1, Oliver Marcel Geier2, Dietbert Hahn1, Herbert Köstler1 1Universität Würzburg, Würzburg, Germany; 2Rikshospitalet University Hospital, Oslo, Oslo, Norway

A new method "generalized density weighted imaging" is presented that allows simultaneously to optimize the SNR and the SRF for sequences with non – constant magnetization (SR sequences, EPI, FSE) during data acquisition.

1341. Design Metrics for Data Undersampling and Weighting Strategies James G. Pipe1 1Barrow Neurological Institute, Phoenix, Arizona , USA

There is great interest in undersampled data collection, particularly for Non-Cartesian MRI, as a means to decrease scan time at the minimal expense of aliasing the high spatial frequencies. This work presents a framework in which both relative SNR and aliasing may be compared between different trajectories and data weighting schemes (necessary for nonuniformly sampled data). Ultimately this will aid in both designing and choosing specific trajectories and data-weighting methods.

Poster Sessions

239

1342. An Improved Analytical Solution for Variable Density Spiral Design Tiejun Zhao1, Youngxian Qian2, Yik-Kiong Hue2, Tamer S. Ibrahim2, Fernando Boada2 1Siemens Medical Solutions, USA, Pittsburgh, Pennsylvania, USA; 2University of Pittsburgh, Pittsburgh, Pennsylvania, USA

An improved analytical solution was presented for designing the variable density spiral trajectory. The maximum slew rate of the trajectory generated from the new method was tested for different k-space oversampling factors and varied spiral segments. Compared to the previous method, the new spiral trajectory design method eliminated the slew rate overflow around the k-space center and only slightly increased the total spiral readout duration. The phantom results showed an improved imaging quality for the images acquired with trajectories generated from the new method.

1343. Comparison of Three Radial Trajectories for Highly Time-Resolved, Short TE Imaging Kuan J. Lee1, Jim M. Wild1 1University of Sheffield, Sheffield, UK

In certain applications, e.g. Hyperpolarized 3He of the lung, both good time resolution and short TE is required to obtain dynamic information in the presence of field inhomogeneities. Symmetric radial, asymmetric echo radial and Quark trajectories are compared to discover (i) which trajectory recovers most signal in the least time under conditions of short T2 and off-resonance (ii) which trajectory gives fewest artifacts when angularly undersampled for increased time resolution. Our simulations show that Quark gives higher time-resolution than symmetric radial, and recovers signal better than asymmetric echo radial. Therefore we conclude Quark represents a good compromise.

1344. Temporal Stability of 3D-PR Based on Multidimensional Golden Means: Simulation and Implementation Rachel Wai-chung Chan1, Donald Bruce Plewes2 1University of Toronto, Toronto, Canada; 2Sunnybrook Health Sciences Centre, Toronto, Canada

Adaptive sampling of k-space allows images in dynamic contrast-enhanced MRI to be reconstructed at various spatial and temporal resolutions from the same dataset. A golden-angle radial k-space sampling scheme achieves this flexibility in-plane with samples incremented by the golden angle. We extend this method to 3D Projection Reconstruction (3D-PR) using multidimensional golden means, which are derived from modified Fibonacci sequences. Using both simulations and experiments, we show that the golden 3D-PR approach has improved temporal stability compared to conventional 3D-PR.

1345. Theoretical and Experimental Aspects of Time Shared Sweep Excitation Using HSn Pulses Djaudat Idiyatullin1, Curt Corum1, Steen Moeller1, Michael Garwood1 1CMRR, University of Minnesota, Minneapolis, Minnesota, USA

An MRI method called SWIFT (SWeep Imaging with Fourier Transform), has significant benefits for studying objects with ultra fast spin-spin relaxation rates. SWIFT uses swept RF excitation and virtually simultaneous signal acquisition in a time-shared mode. This work investigates frequency-modulated pulses of the HSn family as excitation pulses and how the excitation property of pulses varies with the introduction of the gaps needed for acquisition. The quality of the resulting images highly depends on the fidelity of excitation profile, which can be maximized by oversampling the pulse function. For illustration, 3D SWIFT images of human head are presented and discussed.

1346. Comparison of Simple and B1-Compensated Spin-Lock Preparation Techniques at Strong B0 Magnetic Field Inhomogeneities Petros Martirosian1, Michael Deimling2, Berthold Kiefer2, Nina Franziska Schwenzer1, Fritz Schick1 1University of Tübingen, Tübingen, Germany; 2Siemens Medical Solutions, Erlangen, Germany

The purpose of this work was a comparison between a simple Spin-Lock (SL) and a B1-compensated SL preparation technique at strong B0 magnetic field inhomogeneities. The behavior of the spin magnetization is described by the rotating matrix formalism. Measurements with a water phantom were performed at 1.5 T using a SL magnetization-prepared gradient echo sequence. Experimental and theoretical results show that B1-compensated SL pulse preparation works well if the SL pulse amplitude is much higher than static local field inhomogeneities. In body regions with strong B0-field inhomogeneities, the simple SL pulse is advantageous for acquisition of artifacts-free images.

1347. Double Inversion Recovery 3D FSE with 2D-Centric Encoding Reed F. Busse1, Daniel W. Rettmann2, H Glenn Reynolds3, Sterling C. Johnson4, Howard A. Rowley4 1GE Healthcare, Madison, Wisconsin, USA; 2GE Healthcare, Rochester, Minnesota, USA; 3GE Healthcare, Boston, Massachusetts, USA; 4University of Wisconsin, Madison, Wisconsin, USA

Double Inversion Recovery (DIR) nulls CSF and white matter to better visualize gray matter and white matter lesions. A 3D FSE readout with centric view ordering minimizes TE and maximizes SNR, but may result in blurring. A new 2D-centric view ordering for 3D FSE is compared to conventional 1D-centric. Variable flip refocusing is also examined, exploring the trade offs between resolution, SNR and scan time enabled by varying the minimum refocusing flip angle α min) and echo train length. It is found that 2D-centric view ordering results in higher resolution than 1D-centric and resolution can be further enhanced by reducing α min.

1348. Adiabatic Selective Excitation in Single-Slab 3D Turbo Spin Echo Imaging Jaeseok Park1, John P. Mugler III2 1Siemens Medical Solutions, Erlangen, Germany; 2University of Virginia, Charlottesville, USA

Spatially selective single-slab three-dimensional (3D) turbo spin echo (SE) sequence has been recently developed to increase imaging efficiency employing a highly selective excitation radio-frequency (RF) pulse, very short non-selective refocusing pulses, and variable low flip angles with long echo trains. Despite the enhanced imaging efficiency, this sequence is sensitive to spatially varying B1 amplitude, in particular, at high field, generating non-uniform signal-intensity or contrast over the field-of-view. The purpose of this work is to develop a version of single-slab 3D turbo SE sequence less prone to B1 inhomogeneity without compromising the imaging efficiency using composite adiabatic selective excitation.

1349. Optimized MRI Gradient Waveforms for Acoustic Noise Reduction Marcel Segbers1, Carlos V. Rizzo S. 1, Hendrik Duifhuis1, Hans Hoogduin1 1University Medical Center Groningen, University of Groningen, Groningen, Netherlands

The noise produced by MR scanners is a major concern. A framework is presented that allows the construction of trapezoidal gradient waveforms that inherently damp two resonance frequencies of the gradient coil. An example is provided which shows a 9 dB reduction in sound pressure level.

Poster Sessions

240

PROPELLER Hall D Wednesday 13:30-15:30

1350. Advantages of Long-Axis PROPELLER EPI Via K-Space Weighting: Comparison of Point Spread Function with Short-Axis PROPELLER EPI Tzu-Chao Chuang1, Teng-Yi Huang2, Fu-Nien Wang3, Hsaio-Wen Chung1 1National Taiwan University, Taipei, Taiwan; 2National Taiwan University of Science and Technology, Taipei, Taiwan; 3National Tsing Hua University, Hsinchu, Taiwan

Due to the largely shortened echo spacing, short-axis PROPELLER EPI (SAP-EPI) reduces the image blurring without the k-space weighting scheme, which has been previously proposed for de-blurring in long-axis PROPELLER EPI (LAP-EPI) by emphasizing data suffering less from off-resonance field during the combination of blades. Results in this simulation study revealed that the k-space weighting scheme dramatically improved sharpness on LAP-EPI by suppressing side lobes of point spread function in magnitude, while little influence was found for SAP-EPI. As a result, LAP-EPI using a proper weighting function has potentials to obtain images without blurring at the cost of SNR.

1351. PROPELLER EPI Using Asymmetric Blades: A Preliminary Study on Point Spread Function Fu-Nien Wang1, Tzu-Chao Chuang2, Teng-Yi Huang3 1National Tsing Hua University, Hsinchu, Taiwan; 2National Taiwan University, Taipei, Taiwan; 3National Taiwan University of Science and Technology, Taipei, Taiwan

Blades with asymmetric number of positive and negative phase encoding lines are implemented to long-axis PROPELLER EPI. Simulations and in vivo experiments are performed. The point spread function investigated in this study validate that the proposed method could reduce the image blurring effect introduced by distorted EPI blade.

1352. 3D SAP-EPI for Self-Navigated T1w Spoiled Gradient Echo Imaging Samantha J. Holdsworth1, Stefan Skare1, Anders Nordell2, Rexford D. Newbould1, Roland Bammer1 1Stanford University, Palo Alto, California , USA; 2Karolinska University Hospital, Stockholm, Sweden

3D T1w Spoiled Gradient Echo (SPGR) imaging is commonly used in the clinical care due to its high gray-white matter contrast and isotropic resolution. While the short TR makes the total scan time reasonable (~3-10 mins), it is prone to motion-induced ghosting. Short-axis readout propeller EPI (SAP-EPI) has been suggested as an approach to efficient self-navigated imaging. A 3D GRE version of the SAP-EPI sequence is implemented here, by acquiring 3D ‘bricks’ instead of blades. We demonstrate motion and distortion-corrected phantom data from controlled motion experiments. Initial human images acquired in a sub-minute scan time are presented.

1353. View-Sharing PROPELLER with Pixel-Based Optimal Blade Selection (POBS) for Dynamic Contrast-Enhanced MRI Tzu-Chao Chuang1, Fu-Nien Wang2, Teng-Yi Huang3, Chih-Ching Wu1, Hsaio-Wen Chung1 1National Taiwan University, Taipei, Taiwan; 2National Tsing Hua University, Hsinchu, Taiwan; 3National Taiwan University of Science and Technology, Taipei, Taiwan

A novel method termed pixel-based optimal blade selection (POBS) to minimize reconstruction artifacts in dynamic contrast-enhanced view-sharing PROPELLER imaging due to under-sampled outer k-space data. POBS is based on an iterative process to search for one set of blades exhibiting the closest image contrast with the target blade, on a pixel-by-pixel basis by least square error estimation. Results from computer simulations and animal experiments show that POBS yields errors less than 15% with five-fold acceleration as compared with the fully sampled images, with reduction of reconstruction artifacts visually perceivable.

1354. CNR Optimization in Variable Pitch PROPELLER MRA Nicholas R. Zwart1, James G. Pipe1 1Barrow Neurological Institute, Phoenix, USA

The optimization of inflow enhancement in Variable Pitch PROPELLER relies on the fine tuning of the RF-chirp pulse design, refocussing of slice selective gradient and the order in which blade-slabs are overlapped. These mechanisms provide eight distinctive parameters that are optimized in terms of an image quality metric that is constrained through the experimental results using a custom flow phantom.

1355. BLADE-VAT for Geometric Distortion Correction Guobin Li1, Bida Zhang1, Hua Guo, Qiang Zhang1 1Siemens Mindit Magnetic Resonance Ltd., Shenzhen, People's Republic of China

The View angle tilting (VAT) corrects for in-plane geometric distortion from field inhomogeneity, but may introduce serious image blurring. In this abstract,a novel method, called BLADE-VAT, which employs low resolution acquisition in readout direction, provides high efficient reduction of such blurring.

1356. Accelerating PROPELLER-MRI by Means of Under-Sampling and Iterative Image Reconstruction Using the Non-Uniform Fast Fourier Transform Ashish A. Tamhane1, Mark A. Anastasio1, Konstantinos Arfanakis1 1Illinois Institute of Technology, Chicago, Illinois, USA

PROPELLER-MRI is a multi-shot fast spin-echo (FSE) data acquisition technique with reduced sensitivity to motion and B0 inhomogeneities. However, PROPELLER acquisitions are at least 50% slower than conventional FSE. Under-sampling k-space in PROPELLER by reducing the number of blades per acquisition, while increasing the distance between lines, can significantly reduce imaging time, but leads to severe image artifacts when reconstructing images using conventional gridding. In this study, we investigated the trade-off between imaging time, artifacts and noise, for under-sampled PROPELLER acquisitions with iterative reconstruction using the non-uniform fast Fourier transform.

Poster Sessions

241

SSFP Methods Hall D Thursday 13:30-15:30

1357. Partially Dephased SSFP for Elimination of Dark Bands Brian A. Hargreaves1 1Stanford University, Stanford, California , USA

Balanced SSFP imaging sequences provide high signal-to-noise, rapid imaging, and diagnostically useful contrast, but their clinical utility is limited primarily by the dark-band artifacts resulting from off-resonance effects, especially at 3.0T. This work demonstrates that using an unbalanced gradient immediately before and after the readout, combined with a modified reconstruction, a signal with balanced SSFP characteristics and no dark band artifacts can be obtained. The technique is demonstrated in phantoms and human scans.

1358. A Simplified Model for Stabilizing Alternating TR SSFP Sequences Hsu-Lei Lee1, Krishna S. Nayak1 1University of Southern Califonia, Los Angeles, California , USA

An efficient initial preparation is critical for reducing the transient signal fluctuation in non-continuous steady-state imaging. For conventional SSFP, LeRoux derived a Fourier relation between RF amplitude increments and the resulted oscillatory residues. In alternating TR SSFP the Fourier relation is also altered and the preparation scheme has to be modified. We utilized the SU2 formalism to build a simplified model for alternating TR SSFP sequences and present a design method that can be applied to arbitrary repetition times and RF phase cycling combinations. This approach is used to design stabilizer sequences for ATR-SSFP and wideband SSFP.

1359. On the Spoiler Gradient in RF-Spoiled Gradient Echo Sequences Jochen Leupold1, Jürgen Hennig1, Klaus Scheffler2 1University Hospital Freiburg, Dept. of Diagnostic Radiology, Medical Physics, Freiburg, Germany; 2MR Physics, Department of Medical Radiology, University Hospital of Basel, Basel, Switzerland

RF-spoiled gradient echo sequences are widely used in clinical MRI. However, the theoretical description of the measured signal is not trivial, as a pseudo steady state of the voxel magnetisation is built up. We demonstrate that the well known occasional occurrence of ghost artifacts is a direct consequence of the existence of the PSS, and that there is no rigid rule for the needed moment of the spoiler gradient of an RF spoiled gradient echo sequence.

1360. Banding Reduction in SSFP Imaging Through Accurate, Image-Based Estimation of the SSFP Sensitivities Tolga Çukur1, Michael Lustig1, Dwight Georger Nishimura1 1Stanford University, Stanford, California , USA

Balanced steady-state free precession (SSFP) imaging offers high SNR efficiency within short scan times, but suffers from banding artifacts in the presence of strong field inhomogeneities. A common approach is to combine multiple SSFP images with different phase-cycling schemes. There is an inherent trade-off between SNR and the level of banding artifact reduction for most combination methods. In this work, accurate estimates of the SSFP sensitivities are obtained from multiple phase-cycled acquisitions using the magnitude-weighted complex-sum combination as an initial reference. Banding-free images with true SSFP contrast are reconstructed without sacrificing SNR performance.

1361. Synthesis of Multiple Phase Cycled SSFP Images to Remove Band Artifacts as Well as to Improve the SNR by Use of a Spectral Decomposition Kwan-Jin Jung1, 2 1Univ. of Pittsburgh & Carnegie Mellon Univ., Pittsburgh, Pennsylvania, USA; 2University of Pittsburgh, Pittsburgh, Pennsylvania, USA

The band artifacts in SSFP can be removed by MIP of the multiple acquisitions of the phase cycled SSFP images. MIP, however, cannot take the effect of averaging of the multiple images to improve the SNR. There were two reported methods, i.e., the complex sum and the squared sum, that had claimed to achieve both objectives. These two methods, however, could not be confirmed to achieve the major objective of the band artifacts removal. A new method to achieve both effects has been developed by use of the spectral decomposition of each phase cycled image into the low and high frequency components. The low frequency components are processed by MIP, while the high frequency components are averaged. The MIP of the low frequency components and the average of the high frequency components are summed, and results in the synthesized image that is free from the band artifacts with the improved SNR.

EPI - Corrections Hall D Monday 14:00-16:00

1362. Ghost Reduction for Oblique EPI Using Entropy Based Compensation of Phase Encoding Blips Magnus Mårtensson1, 2, Anders Nordell1, 2, Bo Nordell1, 2, Stefan Skare3 1Karolinska University Hospital, Stockholm, Sweden; 2Karolinska Institute, Stockholm, Sweden; 3Stanford University, Stanford, California , USA

A new sequence has been developed to be used as a calibration scan with an altering compensation blip factor for phase encoding, followed by an entropy calculation to find the best compensation blip factor. This method can be used both with single and multi-shot EPI sequences with equally good ghost reduction. Using this calibration scan for each scan plane angle in the exam is a robust technique that results in a major improvement of ghosting artifact suppression for oblique EPI scans. The presented method has great potential when implemented in oblique EPI such as fMRI, DWI, PWI and cardiac imaging.

Poster Sessions

242

1363. Ghost Reduction for Oblique EPI Using Entropy Based Regridding Magnus Mårtensson1, 2, Mathias Engström1, 2, Bo Nordell1, 2 1Karolinska University Hospital, Stockholm, Sweden; 2Karolinska Institute, Stockholm, Sweden

In oblique EPI acquisitions data is sampled in a Cartesian coordinate system, but phase offsets, due to system time delays and eddy currents, will cause the phase encoding lines to be non-equidistantly separated, resulting in non-Cartesian data and thus ghosting. This study proposes a non-Cartesian approach for Cartesian data sets, using entropy calculations to regrid data in order to reduce ghosting artifacts.

1364. Phase and Amplitude Correction in Bipolar Multi-Gradient-Echo Water-Fat Imaging Holger Eggers1, Peter Koken1, Peter Boernert1 1Philips Research Europe, Hamburg, Germany

Gradient system and receive coil imperfections give rise to differences in phase and amplitude between the signal from odd and even echoes in bipolar multi-gradient-echo imaging. A reliable water-fat separation with generalized multi-point Dixon methods based on data from such acquisitions requires a suitable compensation for these imperfections. In this work, a spatially resolved estimation and subsequent correction of phase and amplitude errors is suggested. It is demonstrated to substantially reduce artifacts in whole-body water-fat imaging with continuous table movement.

1365. Multiple-Channel EPI Phase Correction for SENSE Based Image Reconstruction Fred J. Frigo1, Sangwoo Lee1, R. Scott Hinks1 1GE Healthcare, Waukesha, Wisconsin, USA

Inherent in the data collection scheme for Echo Planar Imaging (EPI) are phase errors that lead to image artifacts when left un-corrected. One method for reducing phase errors is to use the nearest-neighbor EPI phase correction approach. For SENSE based image reconstruction, the phase characteristics between channels must be preserved after EPI phase correction. The proposed method of applying nearest-neighbor EPI phase correction for each spatial location and each channel provides a robust and highly effective phase correction technique for SENSE based EPI that can accommodate double oblique scan geometries and has demonstrated excellent image quality.

1366. New Algorithm of Correction for Eddy Current-Induced Distortion of DWI Yung-Chin Hsu1, Ching-Han Hsu1, Wen-Yih Isaac Tseng2 1National Tsing Hua University, Taiwan; 2National Taiwan University College of Medicine and Hospital, Taiepi, Taiwan

In DWI, diffusion gradients usually incur residual eddy currents which lead to gross geometry distortions. Previous retrospective methods usually assume the deformation field is linear which may not be true for high b-value DWI images. In the present study, we propose a generalized algorithm incorporating with two DWI images which are acquired with opposite diffusion gradients. With this algorithm, higher order of the deformation field can be taken into consideration. The proposed method is applicable to DSI or QBI dataset where high b-value is used and data points are symmetric about the origin in the q-space.

Flow Quantification Methods & Applications Hall D Tuesday 13:30-15:30

1367. Higher Order Weighted Least-Squares Phase Offset Correction for Improved Accuracy in Phase-Contrast MRI Tino Ebbers1, Henrik Haraldsson1, Petter Dyverfeldt1, Andreas Sigfridsson1, Marcel Warntjes1, Lars Wigström1 1Center for Medical Imaging Science and Visualization (CMIV) and Linköping university, Linköping, Sweden

Phase-contrast magnetic resonance imaging has the ability to accurately measure velocities. Unwanted spatially varying phase offsets caused by eddy currents are often corrected by estimating a linear fit of the phase values from either a number of manually defined areas or by semi-automatic detection of stationary tissue. In many applications a linear model is no longer sufficient to describe the phase offset variations. In this study we investigate the variation of the phase offset over the complete 3D volume of interest and propose a completely automated correction approach based on a weighed fit of a high order polynomial.

1368. Velocity Mapping in Highly Stenotic Tubes by the Use of Short-Echo Spiral Acquisitions Anders Nilsson1, Einar Heiberg2, Freddy Ståhlberg1, Karin Markenroth Bloch3 1Lund University, Lund, Sweden; 2Lund University Hospital, Lund, Sweden; 3Philips Medical Systems, Lund, Sweden

Measurement of peak-velocities in stenotic blood vessels is important in order to estimate the severity of occlusions. As stenotic vessels often present complex flow patterns, lower echo times is desirable. We have evaluated a spiral phase-contrast gradient echo (PC-GRE) sequence together with a conventional cartesian PC-GRE sequence and a k-t BLAST accelerated cartesian GRE sequence (k-t factor of 5) in a stenotic phantom, with respect to flow volume and peak-velocity. The results show that the spiral sequence can be used to depict both flow volume and peak-velocity correctly in shorter acquistion times than a k-t BLAST accelerated gradient sequence.

1369. Efficient Data Acquisition for MR Doppler Daeho Lee1, Adam Bruce Kerr1, Juan Manuel Santos1, Bob Sueh-Chien Hu2, John Mark Pauly1 1Stanford University, Stanford, USA; 2Palo Alto Medical Foundation, Palo Alto, USA

MR Doppler is a technique that provides real-time imaging of the velocity profile of blood flow analogous to Doppler ultrasound imaging. It provides a mechanism for quickly interrogating valvular flow characteristics, either for identifying valvular stenoses or regurgitant flow. To detect peak velocity of patients, velocity field of view is often required to be in the range -4m/s ~ +4m/s, which results in a lower spatial resolution. We present a flexible design method that makes it easier to realize the desired k-space trajectory in a time-optimal way and this can be used to achieve higher spatial resolution.

Poster Sessions

243

1370. Velocity Contour Mapping for Rapid Practical Flow Examination Ludovic de Rochefort1, Thanh Nguyen1, Pascal Spincemaille1, Yi Wang1 1Weill Medical College of Cornell University, New York, New York, USA

Flow-selective pulses have been proposed using velocity encoding gradients between several RF excitations. Here, we describe a technique to obtain a single image containing velocity isocontours encoded in signal amplitude by tagging in the velocity domain. This method, that provides an original way to look at velocity, is validated on phantom and applied in vivo.

1371. Optimized Pre-Processing Strategy for the Correction of Gradient Field Inhomogeneities in 3D-PC-MRI Daniel Giese1, Jelena Bock1, Aurelien Stalder1, Ramona Lorenz1, Michael Markl1 1University Hospital Freiburg, Freiburg, Germany

Phase Contrast MRI is widely used to assess and quantify blood flow and tissue motion. In particular for applications analyzing 3D blood flow within large volumes gradient non-linearities can introduce substantial errors in the encoded velocities. This study presents an optimized pre-processing strategy to retrospectively correct velocity data. Application in phantom studies demonstrated its correction impact on velocity encoded data and confirmed the necessity for a systematic correction of the effect of gradient imperfections on 3D Phase Contrast measurements.

1372. Effect of Voxel Size, Image Orientation, VENC and TE on Phase Contrast Measurements in Turbulent Stenotic Jets Kieran R. O'Brien1, Brett R. Cowan1, Andreas Greiser2, Alistair A. Young1 1University of Auckland, Auckland, New Zealand; 2Siemens, Erlangen, Germany

Aortic Stenosis may lead to turbulent jets of more than 400cm/s. Often these jets suffer from significant errors in peak velocity and flow due to intravoxel dephasing. The factors affecting the accurate measurement of these high velocity turbulent jets remains unclear. We have investigated, using up-to-date gradient hardware, the influence of TE, voxel size, velocity encoding and image orientation relative to the jet . All of which have previously been found to cause signal loss and intravoxel dephasing in high velocity turbulent jets.

1373. Clinical Evaluation of Aortic Coarctation with 4D Flow MR Imaging Michael D. Hope1, Thomas A. Hope1, Karen Ordovas1, Alison Meadows1, David Saloner1, Gautham P. Reddy1, Marc T. Alley, Charles B. Higgins1 1UCSF, San Francisco, California , USA

In order for 4D Flow to be a clinically viable tool for evaluation of aortic coarction, it must be reasonably fast and generate reliable blood flow data, as well as offer advantages over the standard MR protocol. We address these first two objectives using parallel imaging in a direct comparison of 4D Flow and 2D phase contrast data in patients. With regard to its advantages, 4D Flow allows does not require prospective placement of 2D planes for PC acquisition, and offers unique visualization of flow data that is not available by traditional 2D PC imaging.

1374. Late Consequences After Surgery of Left Sided Diaphragmatic Hernia in Children: Lung Volumes and Blood Flow Nasreddin Abolmaali1, Knut Götzelt2, Arne Koch1, Christian Vogelberg3, Michael Laniado, Gabriele Hahn2 1OncoRay, TU Dresden, Dresden, Germany; 2Pediatric Radiology, Dresden, Germany; 3Pediatric Pulmonology, Dresden, Germany

To compare pulmonary arterial and cardiac findings in children operated for left-sided diaphragmatic hernia in comparison with healthy children. At least six years after surgery, patients received a clinical interview, pulmonary function testing and echocardiography. Furthermore, all children received MRI examinations for functional cardiologic evaluation and velocity encoded flow measurements of pulmonary arteries. Examinations other than MRI revealed neither pathologic findings nor significant differences between volunteers and patients. On the other hand, MRI showed significantly reduced cardiac volumes, while the heart rate was increased. The flow parameters of the left pulmonary artery in patients were reduced and pulmonary blood flow was shifted from the left to the right main pulmonary artery. These findings indicate persistent pulmonary hypotrophia on the operated side.

1375. Accurate Quantification of Aortic Regurgitation with PC-MRI Meera Sekar1, John Sheehan, Jennifer Berliner, Issam Mikati, James Carr2 1Northwestern University, Chicago, USA; 2Northwestern University, USA

This retrospective study is a comparison of MRI quantification of aortic regurgitation at varying anatomic levels in relation to the aortic valve with Echocardiographic quantification.

1376. Hemodynamic Response to Exercise in Small Abdominal Aortic Aneurysms Adam Sebastian Tenforde1, Christopher P. Cheng1, Kelly Y. Suh1, Andrea S. Les1, Ronald L. Dalman2, Robert J. Herfkens1, Charles A. Taylor1 1Stanford University, Stanford, USA; 2Stanford University Medical Center, Stanford, USA

Abdominal Aortic Aneurysm (AAA) is a vascular disease whose course may be altered by exercise. Six male patients with small AAA were compared to eight healthy control patients while performing lower limb exercise on an MR-compatible bicycle. PC-MRI data was collected at supraceliac, infrarenal, and mid-aneurysm positions on a GE 0.5T MRT. Measured outcomes include average mean flow and oscillatory flow index (OFI). AAA patients had similar values of average mean flow to control patients during rest and exercise, and AAA patients reduced OFI during exercise. These results suggest mild exercise may reduce adverse hemodynamic conditions in AAA disease.

1377. Vortex Ring Formation in Diastolic Dysfunction: Phase Contrast MRI of Left Ventricular Filling William Sean Kerwin1, David Owens1, Jean Hertzberg2, Robin Shandas2, Edward Gill1 1University of Washington, Seattle, Washington, USA; 2University of Colorado, Boulder, Colorado , USA

We developed a method for viewing complex 3D vortex ring formation in the left ventricle during filling using CINE phase-contrast MRI. We evaluated the potential of the method by comparing vortex ring formation in 5 subjects with diastolic dysfunction to 5 normal subjects. Two distinct vortices were observed during filling, with the first appearing significantly weaker and delayed in subjects with diastolic dysfunction. We conclude that vortex ring characteristics observed with this method may be valuable for diagnosis and staging of diastolic dysfunction.

Poster Sessions

244

1378. Breathhold Time-Resolved Three-Directional MR Velocity Mapping of Aortic Flow in Patient Follow-Up After Aortic Valve-Sparing Surgery Xin Liu1, Peter Weale, Randall Ramsay1, Aya Kino1, Gert Reiter, Karin Dill1, James Carr1 1Northwestern University, Chicago, Illinois, USA

To evaluate the potential of breathhold time-resolved three-directional MR velocity mapping for the follow-up in patients after aortic valve-sparing surgery, 13 patients with valve-sparing surgery as well as 10 healthy volunteers and 12 patients with ascending aortic aneurysm were evaluated by time-resolved three-directional MR velocity mapping. Aortic laminar flow, turbulent flow, and the presence of vertical flow in the sinuses of Valsalva were analyzed. Breathhold time-resolved three-directional MR velocity mapping allows for the detection of flow patterns in aortic root and ascending aorta. Normal laminar flow in the ascending aorta and vertical flow in the sinuses of Valsalva can be restored in patients after aortic valve-sparing surgery. Evaluation of aortic flow patterns using MR velocity mapping may be a useful indicator for outcome of patients with aortic valve-sparing surgery.

1379. Non-Contrast-Enhanced MRA of the Renal Vasculature with the BSSFP Dixon Method Randall B. Stafford1, 2, Mohammad Sabati1, 2, Michael J. Haakstad2, M Louis Lauzon1, 2, Houman Mahallati1, 2, Richard Frayne1, 2 1University of Calgary, Calgary, Canada; 2Foothills Medical Centre, Calgary Health Region, Calgary, Canada

Renal artery stenosis is a major cause of renal insufficiency. Gadolinium-based MR contrast agents have been linked to nephrogenic systemic fibrosis in patients with renal insufficiency. The purpose of this research was to collect non-contrast-enhanced MR angiograms of the renal arteries using the balanced steady-state free precession Dixon method in healthy volunteers. The results showed that the technique produced images with good fat-suppression and strong arterial vessel conspicuity. We conclude that this technique is suitable for non-contrast-enhanced renal MR angiograms.

Fat-Water Imaging Hall D Wednesday 13:30-15:30

1380. k-T Accelerated IDEAL for Robust Water-Fat Dynamic Imaging Jeffrey Tsao1, Yun Jiang1 1Novartis Institutes for BioMedical Research, Cambridge, Massachusetts, USA

IDEAL is an attractive water-fat separation method. A drawback is the prolonged scan time due to the need to acquire at least 3 echo times. Dynamic imaging with IDEAL can be combined with k-t acceleration to reduce scan time below the nominal time for a single image. In this work, we demonstrated net acceleration factors of 4.3x and 6.3x, resulting in scan times of 70% or 47% compared to a single-average scan. The combination of IDEAL and k-t acceleration is favorable since the IDEAL echo times present an extra data dimension, which can be used for signal packing and acceleration.

1381. Water-Fat Separation with IDEAL, Undersampled Radial Acquisition, and Off-Resonance Deblurring Yun Jiang1, Jeffrey Tsao1 1Novartis Institutes for BioMedical Research, Cambridge, Massachusetts, USA

In this work, we combined radial acquisition with IDEAL water-fat separation and off-resonance correction. Phantom and in vivo data demonstrate that it is a robust method to accelerate fat-water separation.

1382. Water-Fat Decomposition with Regularized Field Map Wonseok Huh1, Jeffrey A. Fessler1, Alexey A. Samsonov2 1University of Michigan, Ann Arbor, Michigan, USA; 2University of Wisconsin-Madison, Madison, Wisconsin, USA

We proposed a method for water-fat decomposition with regularized field map estimation. In this work, we describe a penalized-likelihood method for jointly estimating water, fat, and the field map. The method uses the a priori knowledge that field maps are usually smooth by including a regularization term in the cost function. The fat and water components can be solved for analytically as a function of the field map. By providing a field map estimate that is inherently smooth even in regions of low signal intensity, the method may yield improved water and fat images.

1383. Simultaneous Water-Fat and T2* Mapping with 3-Point Acquisitions Qing-San Xiang1 1University of British Columbia, Vancouver, Canada

Water and fat images are obtainable using either gradient-echo or spin-echo sequences with incremental echo shifts. Similar sequences can also be used for T2* mapping. This work demonstrates simultaneous mapping of both water-fat and T2* with as few as 3 acquisitions. Three complex images were acquired with water and fat vectors at (90, 270, 450) degrees, forming Three-Orthogonal-Phase (TOP) sampling. Orthogonality between water and fat allows decoupling of T2* and chemical shift effects. T2* map is readily computed from three otherwise identical magnitude images while water-fat images are obtained after phase correction with Regional Iterative Phasor Extraction (RIPE).

1384. Water Fat Shift Displacement Artifact Correction in Two Point Dixon Imaging Olof Dahlqvist Leinhard1, 2, Andreas Johansson1, Peter Lundberg1, 2 1Linköping University, Linköping, Sweden; 2Center for Medical Image Science and Visualization (CMIV), Linköping, Sweden

The chemical shift artifact in a two point Dixon acquisition can be removed by an iterative solver taking advantage of the known fat water shift. A simple implementation has been made and the initial results are presented with promising results.

1385. Multislice Water-Fat Imaging with Simultaneous Echo Refocusing (SER-Dixon) Kuan J. Lee1 1University of Sheffield, Sheffield, UK

A new multislice water-fat imaging sequence is introduced which combines Simultaneous Echo Refocusing (SER) with Partially-Opposed-Phase (POP) acquisition. By slightly increasing the interval between echoes from one slice, echoes from another slice may be fitted in between.

Poster Sessions

245

1386. TIDE BSSFP as a Fat-Suppression Preparation Yin-Cheng Kris Huang1, Hsiao-Wen Chung2, Teng-Yi Huang3 1National Taiwan University , Taipei City, Taiwan; 2National Taiwan University, Taipei City, Taiwan; 3National Taiwan University of Science and Technology, Taipei City, Taiwan

The Transition into Driven Equilibrium balanced steady-state free precession (TIDE bSSFP) sequence has been shown to carry an intrinsic suppression of off-resonance signals after experiencing a certain number of RF pulses, just with an appropriate choice of the timing passing through the k-space center. The stopbands are wide in comparison to other fat-suppression schemes such as CHESS. Therefore, it should be possible to incorporate TIDE bSSFP fat suppression into other routine readout module, by truncating the TIDE bSSFP up to the null point for off-resonance signals. In regions where good shimming is harder to achieve, the wide stopbands of TIDE may be helpful.

1387. RF Phase-Cycling Water-Saturated 3D B-SSFP for Fast Abdominal Fat Imaging Yao Ding1, Anqi Zhou2, Roderick W. McColl1, Paul T. Weatherall1, Qi Peng2 1UT Southwestern Medical Center at Dallas, Dallas, Texas, USA; 2UT Health Science Center at San Antonio, San Antonio, Texas, USA

A fast water-suppressed b-SSFP sequence was reported previously for abdominal fat imaging using a manual f0 shift of -220Hz (at 1.5T) to fat resonant frequency peak to avoid banding artifacts on fat. We propose here a clinically available, automatic phase-cycling b-SSFP scheme to avoid manual f0 shift difficulties. Theoretical analysis of the new phase-cycling approach is provided and three subjects were scanned using both techniques. No image quality difference was noticed, and fat quantification on those images show little differences (<0.5%). Therefore, the proposed approach can replace the previously reported manual f0 shift approach for fast abdominal fat imaging.

1388. Comparison of Fat-Water Separation by 2D RF Pulse and Dixon Method in Balanced Steady-State Free Precession Jing Yuan1, Bruno Madore1, Lawrence P. Panych1 1Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA

2drf pulse excitation is presented as a novel method for fat-water separation in b-SSFP imaging. It has the advantages of only single acquisition and no image post-processing. This study compares fat-water separation by 2-point Dixon method and 2drf pulse in b-SSFP sequence. The results show that 2drf pulse has comparable separation performance to Dixon method. Pros and cons by these two fat-water separation are discussed.

New Methods for Generating Contrast Hall D Thursday 13:30-15:30

1389. Fast Low-Angle Positive-Contrast Imaging with Alternating Repetition Time SSFP Tolga Çukur1, William Overall1, Dwight Georger Nishimura1 1Stanford University, Stanford, California , USA

Methods for generating positive-contrast images from susceptibility-induced magnetic field variations are useful for applications such as the guiding of interventional devices or imaging of super paramagnetic iron oxide (SPIO)-labeled cells. SSFP-based methods, such as fast low-angle positive-contrast SSFP (FLAPS), offer fast imaging and flow insensitivity. However, the level of background suppression can be limited. In this work, we employ the alternating repetition time (ATR) SSFP stop-band to suppress the signal from on-resonant spins. The ATR sequence provides positive contrast with robust suppression for a wide range of flip angles and tissue parameters.

1390. Short T2 Positive Contrast Imaging with Self-Refocused Spiral Pulse Sequence Angus Zoen Lau1, Charles Henry Cunningham1 1Department of Medical Biophysics, University of Toronto, Toronto, Canada

Conventional imaging of superparamagnetic iron oxide (SPIO) particles yields negative contrast in the region surrounding the particles. Recent positive contrast techniques refocus this dephased signal using an off-resonance spin echo sequence. We investigate the possibility of imaging off-resonance short T2 spins using a short TE spiral pulse sequence containing a spectrally-selective self-refocusing RF pulse. A short T2 agar gel model using gadolinium as the field perturber is used to evaluate the performance of this sequence. We demonstrate that the short TE sequence is able to refocus increased signal from off-resonance short T2 spins compared to a spectrally-selective spin echo sequence.

1391. Faster Myelin Imaging in Vivo; Validation of 3D Multi-Echo T2-Relaxation Measurements Shannon Heather Kolind1, Burkhard Mädler2, Alex Lloyd MacKay1 1University of British Columbia, Vancouver, Canada; 2Philips Medical Systems,, Vancouver, Canada

We compared results from a recently introduced 3D multi-echo T2-relaxation imaging technique to the standard single-slice multi-echo T2-relaxation measurement most common in the literature. For 10 healthy controls, myelin water fraction correlated strongly between the techniques (slope=1.00,intercept=-0.91%,R2=0.89,p<0.0001) with significant differences only occurring in peripheral brain. Geometric mean T2 was not significantly different in any brain structure examined except minor forceps. SNR was generally higher using the 3D technique. In conclusion, results from the 3D multi-echo T2-relaxation technique were generally consistent with single-slice results, and achieved 7 times greater brain coverage in similar scan times with higher SNR.

Poster Sessions

246

1392. Voxel-Based Morphometry at 3 Tesla: Which T1-Weighted Sequence is Best? Christine Lucas Tardif1, D Louis Collins1, G Bruce Pike1 1Montreal Neurological Institute, Montreal, Canada

The stability and accuracy of the voxel-based morphometry (VBM) process is crucial in large studies to improve the power of statistical results and minimize regional bias. In this study, we evaluated three protocols, FLASH, MP-RAGE and MDEFT, from the perspective of VBM. Nine volunteers were scanned twice for each protocol. We performed a VBM analysis of grey matter (GM) density between the sequences, as well as GM density scan-rescan variability. The results show large areas of significant difference in GM density and variability between the three protocols, and suggest that MDEFT is best suited to this type of analysis.

1393. MP2RAGE, a Self-Bias Field Corrected Sequence for Improved Segmentation at High Field José P. Marques1, 2, Tobias Kober1, 3, Wietske van der Zwaag1, 2, Gunnar Kruegger1, 3, Rolf Gruetter1, 4 1Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland; 2University of Lausanne, Lausanne, Switzerland; 3Siemens Medical Solutions-CIBM, Lausanne, Switzerland; 4University of Lausanne and Geneva, Switzerland

To improve bias field correction as well as contrast between tissues with different T1’s, the MPRAGE sequence was modified into a MP2RAGE (Magnetization Prepared with 2 RApid Gradient Echoes), which accommodates two gradient echo modules after each inversion, GRETI1 and GRETI2, which are characterized by their two different inversion times (TI1 and TI2) and flip angles α 1 and α 2). The use of the combined images resulted in higher contrast between CSF, GM and WM.

1394. Acceleration of Multi-Echo Spin-Echo Imaging for T2 Mapping Using Single or Multiple Coils Julien Sénégas1, Wei Liu2, 3, Hannes Dahnke1 1Philips Research Europe, Hamburg, Germany; 2National Institutes of Health, Bethesda, USA; 3Philips Research North America, Briarcliff Manor, USA

This work presents a new acceleration method that exploits the temporal correlation of the k-space signal at different echo times to reduce the number of phase-encoding steps in a multi-echo spin-echo sequence. The extension to the case of multiple coils is addressed. The approach is evaluated with respect to SNR and reconstruction artefacts, and compared to SENSE and GRAPPA. For single coil acquisitions, the proposed method represents a new way of reducing the scan time that was not accessible with sensitivity encoding approaches. For multiple coils acquisitions, it extends the existing methods and allows an appreciable improvement in reconstruction quality, limiting especially noise amplification.

1395. "High-Frequency Relaxation" with Contrast Agents Christian Hoehl1, Nouri Elmiladi1, Jessica Mende1, Karl Maier1 1Rheinische Friedrich-Wilhelms-Universität, Bonn, Germany

A new method of contrast may be achieved by using different nanoparticles as high frequency transmitters. Activated by ultrasound radiation, the nanoparticles emit electromagnetic waves within their nearest neighborhood. This produces a change in the relaxation rate, depending on the ultrasound parameters and the physical properties of the tissue.

1396. An Optimal Pulse Sequence for Parahydrogen-Induced Polarization of Heteronuclei Stephen Kadlecek1, Vahid Vadhat1, Kiarash Emami1, Richard A. Guyer1, Robert V. Cadman1, Jiangsheng Yu1, John MacDuffie Woodburn1, Masaru Ishii, 12, Hans Hyonchang Kim1, Warren Gefter1, Rahim R. Rizi1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA; 2Johns Hopkins University, Baltimore, Maryland, USA

We present a closed-form prescription for NMR pulses and delays which maximizes heteronuclear hyperpolarization through transfer of spin order from a coupled nuclear singlet state. This result is applicable to the preparation of MRI contrast agents through the method of Parahydrogen-Induced Polarization. The sequence is derived using a geometric analogy to the evolution of orthogonal density matrix components. We find that the sequence is optimal in that it minimizes sequence duration, and therefore T2-like relaxation, and is less sensitive to pulse imperfections than other prescriptions studied.

1397. Triggered Angiography Non-Contrast Enhanced (TRANCE) of Peripheral Arteries: Optimization of Systolic and Diastolic Time Delays for Electrocardiographic Triggering Andreas Stadlbauer1, Wilma van der Riet2, Markus Scheidegger3, Stephan Gruber4, Erich Salomonowitz1 1Landesklinikum St.Poelten, St. Poelten, Austria; 2European MRI Consultancy (EMRIC), Strasbourg, France; 3Philips AG Medical Systems, Zurich, Switzerland; 4Medical University Vienna, Vienna, Austria

We determined the optimal systolic and diastolic time delays (TD) for ECG-triggering of a non-contrast enhanced MRA (TRANCE) in patients with peripheral arterial disease. We specified the requirements for the systolic images with minimal and the diastolic images with maximum arterial SNR. An ECG-triggered T2w TSE (VISTA) sequence was performed in 12 patients using variable trigger delays for systolic and diastolic phase. The SNR in the popliteal and anterior tibial arteries of systolic and diastolic images were determined. The optimal systolic TD was 14–21ms smaller, the optimal diastolic TD 200ms apart from time of maximum peak velocity.

1398. Spectrally Selective Hard Pulses (SSHP) for Positive Contrast MRI: Theory and Validation Twinkle Gupta1, Saurabh Shah2, Sumeet Virmani, Reed Omary1, Andrew Larson1 1Northwestern University, Chicago, Illinois, USA; 2Siemens Medical Solutions, Chicago, Illinois, USA

We investigated the use of spectrally selective hard pulses (SSHP) for positive contrast MRI of paramagnetic markers. Our primary focus was to study the effects of specific SSHP-parameters (targeted off-resonance and no. of binomial sub-pulses=N) upon marker conspicuity, background and fat suppression. Studies were performed using simulations and phantom models. Background suppression increased with increasing N and targeted off-resonance. Marker conspicuity was higher at lower N and off-resonance values. Fat suppression maximized at 100Hz off-resonance. SSHP pulses offer a promising method for positive contrast MR. Further developments are needed to demonstrate the utility of this technique for in-vivo clinical applications.

Poster Sessions

247

1399. A Novel FLAIR PROPELLER Technique for T1-Weighted Brain Imaging Zhiqiang Li1, Donglai Huo2, Eric Aboussouan2, Xiaoli Zhao3, John Karis2, Leland Hu2, Zhu Li3, James G. Pipe2 1GE Healthcare, Phoenix, Arizona , USA; 2Barrow Neurological Institute, Phoenix, Arizona , USA; 3GE Healthcare, Waukesha, Wisconsin, USA

Spin Echo (SE) sequence is widely used for T1-weighted brain imaging. T1 FLAIR FSE also has drawn significant attention recently due to superior SNR and CNR, and improved lesion conspicuity. However, these techniques are significantly impaired in regions affected by flow artifact, which is even worse in post-contrast imaging. Turboprop is a technique insensitive to flow artifact. In this work, we combine FLAIR preparation with turboprop to produce superior T1 contrast with minimized flow artifact. This technique can be used for both pre- and post-contrast T1 imaging, and has several advantages over current clinical T1 SE protocols.

1400. T1 Mapping of MT Effects in BSSFP Rexford David Newbould1, Marcus T. Alley1, Stefan Ropele2, Roland Bammer1 1Stanford University, Stanford, California , USA; 2Medical University Graz, Graz, Austria

Recent work has presented the concept of magnetization transfer effects in balanced SSFP (bSSFP) acquisitions for calculating MTR maps from variation in the steady-state magnetization. Another quantity of interest is the variation in T1 of the free pool under varying saturation of the bound pool. By prefacing the bSSFP train with an inversion pulse, the transient magnetization progresses towards steady-state with an apparent rate constant known as T1*, which can be related to underlying T1. In this work IR-bSSFP relaxometry is performed with varying direct RF power deposition, which can measure both the variation in steady-state levels and underlying T1.

1401. Magnetization Transfer Effects in Cardiac Balanced SSFP Imaging at 3T Kyunghyun Sung1, Hsu-Lei Lee1, Houchun Harry Hu1, Krishna S. Nayak1 1University of Southern California, Los Angeles, California , USA

Magnetization transfer (MT) in 3T cardiac balanced steady state free precession (bSSFP) imaging can possibly produce a new type of contrast to detect infarcts and inflammation of the myocardial tissue. We evaluate the range of MT ratio (MTR) with different RF pulse elongations by a constant TR (3.6ms – 5.6ms). We also perform multiple measurements to establish variation range in 3T cardiac imaging. The study shows a MTR of 12 – 19% in 3T bSSFP cardiac imaging while a MTR of 30 – 50% has been reported in brain applications.

1402. Integration of Magnetization Preparation Sequences Into SSFP Sequences: A Fat Saturation Example Sergio Andres Uribe1, Reza Razavi1, Tobias Schaeffter1 1Kings College London, London, UK

In this work we present a new method that allows the integration of magnetization preparation sequences into b-SSFP sequence without disturbing the steady state. Gradients and rf pulses are integrating into steady state free precession sequence after certain time interval without the need to stop and re-establish the steady state. An example for fat suppression has been implemented and tested in phantom and volunteers. Other preparation techniques can also benefit from this method, such as regional saturation (REST) or spin labeling.

1403. Dual Acquisition Phase Difference SSFP for Improved Fat Suppression Catherine Judith Moran1, Walter F. Block2 1University of Wisconsin, Madsion, USA; 2University of Wisconsin, Madison, USA

Linear Combination SSFP is one of a number of methods that provide fat-water separation in balanced SSFP. Fat/water separation in this dual pass method suffers when the magnitude of the signal varies between passes. Instead, we recognize the phase difference between the two passes robustly falls into two categories, 0 for water and 180 degrees for fat. Unlike previous phase-sensitive methods, common mode sources of phase error cancel out. Thus an extremely simple reconstruction method can classify fat voxels and remove them. We demonstrate the method in dramatic improvements of contrast in breast and knee imaging.

1404. Balanced Steady-State Free Precession Spatial Gridding Walter Robert Thurmond Witschey II1, Mark A. Elliott, Jeremy Magland1, Ravinder Reddy 1University of Pennsylvania, Philadelphia, USA

Steady-state free precession gridding exploits the external field sensitivity of the balanced gradient echo sequence to generate a uniform image grid. A simple gradient pulse added to the balanced gradient echo sequence 'unbalances' the sequence and generates a grid with spacing proportional to the gradient pulse amplitude and gradient. Potential applications include steady-state diffusion weighting and persistent motion sensitivity.

1405. Simultaneous T1 and T2* Mapping Without B1 Correction Philipp Mörchel1, Gerd Melkus1, Markus Kotas1, Michael Flentje1, Peter Michael Jakob1 1University of Würzburg, Würzburg, Germany

A new method for the simultaneous measurement of T1 and T2* maps is presented. This method is robust against variations in flip angles due to B1 inhomogeneities of the resonator. Moreover, this sequence is time efficient because both parameters can be measured in the time the T1 measurement would take. Another advantage is that there no misregistration artifacts due to motion during a consecutive measurement of the single parameters T1 and T2*.

1406. TRITONE: RF Insensitive T1 Estimator Using SPGR Acquisitions Roman Fleysher1, Lazar Fleysher1, Songtao Liu1, Oded Gonen1 1NYU School of Medicine, New York, USA

We present a method of T1 estimation designed to be free of systematic errors caused by B1 inhomogeneity in which the value of T1 is extracted from three 3D spoiled-gradient-recalled-echo (SPGR) images acquired with EPI readout. The method provides protocols optimized for precision in T1 given available scan time. The precision is comparable to that of the adopted two-SPGR method in the same time and spatial resolution. If the two-SPGR methods are combined with B1 measurement for accuracy, then TRITONE supersedes them in precision in the same total time.

Poster Sessions

248

1407. Intermolecular Zero-Quantum Coherence Imaging in Structured Samples Bernard Siow1, Li Sun1, Andrew M. Blamire1 1Newcastle University, Newcastle upon Tyne, UK

Intermolecular multiple quantum coherence imaging sequences have recently been shown to provide a fundamentally different contrast mechanism to conventional MRI. A numerical study of intermolecular zero-quantum coherence imaging has shown sensitivity to susceptibility gradients at selected distance scales. In this study, an iZQC sequence was implemented and iZQC signal verified. The sequence was used to investigate sensitivity to susceptibility gradients at selected distance scales in structured samples. Images show contrast in areas where susceptibility gradients are present. Furthermore, contrast was modulated by the distance scale selected. Further results suggest that contrast is modulated by specific resonant frequency difference at distance scale selected.

1408. Measurement of T2* Relaxation Time of Cerebral White Matter Structures Using Large-Scale Field Inhomogenetiy Correction Technique in Healthy Volunteers at 3T Akira Sasao1, Mika Kitajima1, Toshinori Hirai1, Hirofumi Fukuoka1, Tomoko Okuda1, Tomoyuki Okuaki2, Shutaro Saiki2, Yasuyuki Yamashita1 1Kumamoto University, Kumamoto, Japan; 2Philips Medical Systems, Japan

We measured T2* values of the five white matter structures, the genu and splenium of the corpus callosum, posterior limb of the internal capsule (PLIC), occipital white matter adjacent to the lateral ventricle and frontal white matter, at 3T using a multi-echo fast field echo sequence with and without the main field inhomogeneity (B0 inhomogeneity) correction in 20 neurologically normal cases. The mean T2* values of all measured white matter regions using B0 inhomogeneity correction was statistically longer than those without B0 inhomogeneity correction. The mean T2* value of PLIC using B0inhomogeneity correction was longest among the five regions.

Relaxometry & Quantitation Hall D Monday 14:00-16:00

1409. Interpolated Estimates of Magnitude, R2*, and Frequency Offset in SS-PARSE Imaging Weidong Tang1, Stanley J. Reeves1, Donald B. Twieg2 1Auburn University, Auburn, Alabama, USA; 2University of Alabama at Birmingham, Birmingham, Alabama, USA

This paper proposes a new reconstruction method for single-shot parameter assessment by retrieval from signal encoding (SS-PARSE). The cubic convolution interpolation is used to reconstruct higher resolution images with limited data from short read-out time. A polynomial approximation is suggested to address the problematic exponential time function in SS-PARSE model. By this approximation, reconstruction algorithm based on conjugate-gradients can be accomplished by FFTs. Results with this method show sharper edges and smoother reconstructions in areas known to be smooth.

1410. Derivation of Optimal Flip Angles Via Minimization of Noise Factor Over Large Range of T1 for Accurate Variable Flip Angle-Derived T1 Estimations Keiko Miyazaki1, David J. Collins1, Dow-Mu Koh1, David J. Hawkes2, Martin O. Leach1, Matthew R. Orton1 1Institute of Cancer Research, Sutton, UK; 2University College London, London, UK

The variable flip angle method allows relatively accurate estimation of T1 in a short time period compared to lengthy inversion recovery methods. Here, we propose a simple and efficient method of obtaining the optimal pair of flip angles which would enable accurate T1 estimations in a sample with a large T1 range by using an optimization scheme. This is of great importance in numerous areas in MRI, particularly in DCE-MRI studies where accurate determination of T1 is crucial in obtaining quantitative parameters which are widely used to monitor disease progression and regression.

1411. Measuring T2 and T2' in the Brain at 1.5T, 3T and 7T Using a Hybrid Gradient Echo-Spin Echo Sequence and EPI Eleanor F. Cox1, Penny A. Gowland1 1University of Nottingham, Nottingham, UK

T2 and T2′ was measured in the brain at 1.5, 3 and 7T using a gradient echo-spin echo (GESE) sequence and T2 was also measured with single shot SE-EPI. Both sequences were used to measure values of T2 in grey (both frontal and occipital) and white matter in four healthy volunteers at all three field strengths. Inverse T2 contrast was seen in the occipital region of the brain. The T2 values measured agreed with previously published data and the GESE sequence was calibrated against SE-EPI results using phantoms.

1412. Measuring T2 and T1 Simultaneously in the Abdomen Using T2-Prepared BTFE at 3T Eleanor F. Cox1, Caroline L. Hoad1, Penny A. Gowland1 1University of Nottingham, Nottingham, UK

It is possible to measure T2 and T1 simultaneously using a T2-prepared balanced turbo field echo sequence (T2-prep bTFE) which has particular application in the abdomen at 3T. The T2-prep bTFE sequence was calibrated against EPI using gel phantoms and was then used to measure T2 and T1 in the kidneys, liver and spleen. The results were comparable to previously published results using spin echo and inversion recovery FSE. The ability to measure T2 and T1 in a reasonable time has important applications in studying changes of gastrointestinal (GI) contents, such as viscosity and dilution, in the GI tract.

Poster Sessions

249

1413. B1 Insensitive Saturation Recovery T1 Measurements at 3 Tesla Using Water Suppression Enhanced Through T1 Effect (WET) Saturation Pulse Frederic Courivaud1, 2, Henrik B.W. Larsson3, 4 1Philips Medical Systems, Oslo, Norway; 2Rikshospitalet, Oslo, Norway; 3Glostrup Hospital, University of Copenhagen, Copenhagen, Denmark; 4Norwegian University of Science and Technology (NTNU), Trondheim, Norway

Quantitative measurements of MR relaxation properties (T1 and T2) are relevant parameters for diagnosis and prognosis of various diseases. T1 measurement is particularly important in the development of T1-based contrast enhanced perfusion measurements. However, most of T1 measurements methods at high field require B1 mapping correction before signal analysis. We demonstrate here the use of optimized four-pulse Water suppression Enhanced through T1 effects (WET) for B1 insensitive saturation recovery T1 measurements at 3T, without the use of B1 mapping. T1 values in accordance with published results and WM/GM segmentation of the brain are shown.

1414. Lipid T2* Determination by Modeling the Intra-Molecular Chemical Shift Effect Christian Graff1, Eric Clarkson1, Kenneth L. Weiss2, Maria I. Altbach1 1University of Arizona, Tucson, Arizona , USA; 2University of Cincinnati, Cincinnati, Ohio, USA

T2* measurements are important for the quantification of physiological events or pathologies related to susceptibility changes in tissue. When fat is present, the T2* signal decay is modulated by the chemical shift of the various hydrogen types that make up the fat molecule leading to improper T2* estimation. In this work we present a signal equation model for extracting T2* for fat, minimizing the effects of the intra-molecular chemical shift.

1415. Magnetization Transfer Effect on T2 Measurement Using Steady-State Free Procession Zhongliang Zu1, Yanming Yu1, Qi liu1, Xuna Zhao2, Min Chen3, Shanglian Bao1 1Peking University, Beijing, People's Republic of China; 2Philips MRI Center, Beijing, People's Republic of China; 3Beijing Hospital, Beijing, People's Republic of China

DESPOT2 is a rapid T2 mapping technique based on acquisition of a pair of or several SSFP images and prior knowledge of T1. However, recent research has reported that in biological tissues the steady-state signals of SSFP deviate from theoretical predictions based on Bloch equations, which could be attributed to magnetization transfer (MT). Therefore, the accuracy of DESPOT2 is doubted. We analysed the MT effect on T2 measurement. Optimized imaging parameters were proposed to avoid the MT effect on T2 mapping.

1416. Towards Online Reconstruction of Quantitative Magnetization-Transfer Imaging Dirk K. Müller1, Thies H. Jochimsen1, Torsten Schlumm1, Harald E. Möller1 1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany

A challenging aspect of quantitative magnetization-transfer (qMT) is the complex model describing a solid and a semi-solid pool exchanging magnetization, causing long scanning times and difficult post processing. We present a fast fitting algorithm for qMT imaging which greatly reduces post-processing times. Based on the model of Ramani, a combination of brute force and Levenberg-Marquardt algorithms leads to a dramatic reduction of processing times which could eventually be used for online reconstruction in future clinical applications.

1417. Magnetic Field and Age Dependence of the Distribution of the Longitudinal Relaxation Time in the Living Human Brain Ana-Maria Oros-Peusquens1, Maija Laurila1, N. Jon Shah1 1Institute of Medicine, Research Centre Juelich, Juelich, Germany

We report the results of a 12-volunteer study on the mapping of the T1 relaxation time at 1.5T, 3T and 4T and its field and age dependence. Three nearly identical whole-body scanners have been employed, operating at field strengths of 1.5T (Siemens Avanto), 3T (Siemens Trio) and 4T (Siemens/Bruker MedSpec). Close to whole-brain T1 mapping was performed using TAPIR, a sequence based on the Look-Locker method, which uses an interleave of slice and time point read-outs for fast multi-slice acquisition whilst maintaining good temporal resolution. The whole-brain histogram of T1 values was fitted using a superposition of three Gaussian distributions. The dependence of the centroids of the WM and GM peaks on field strength was investigated and compared to empirical formulae by Bottomley or Fischer. The age dependence of the centroids was also investigated; no clear behaviour was observed for the WM; a clear decrease of the T1 of GM was found at all three fields.

1418. Estimation of the Inversion-Pulse Efficiency in the Context of Multi-Exponential Analysis of Spin-Lattice Relaxation Christian Labadie1, 2, Jing-Huei Lee3, Harald E. Möller4 1Max Planck Institute for Human Cognitive and Brain Science, Leipzig, Germany; 2University of Leipzig, Leipzig, Germany; 3University of Cincinnati, Cincinnati, USA; 4Max Planck Institute for Human Cognitive and Brain Science, Leipzig, Germany

A CONTIN-based procedure to estimate the inversion-pulse efficiency in the context of multi-exponential longitudinal relaxation is proposed and compared to a mono-exponential three-parameter NLLS fit. Simulations using continuous T1 distributions show that the three-parameter NLLS fit underestimates the efficiency when a small T1 peak is present below 400 ms. Such underestimation of the efficiency is apparent in the white matter of the human brain at 4 Tesla. The novel procedure enables to adequately estimate the inversion-pulse efficiency necessary to perform a reliable multi-exponential analysis of spin-lattice relaxation.

1419. Ultrashort T2* Relaxometry Using Conventional Multiple Gradient Echo Sampling with S0 Fitting: Validation with Quantitative UTE (QUTE) Imaging Peter Roland Seevinck1, Clemens Bos2, Chris J.G. Bakker1 1University Medical Center, Utrecht, Netherlands; 2Philips Medical Systems, Best, Netherlands

To quantify ultrashort T2* components associated with the increasing interest in high field MR as well as in (super-)paramagnetic contrast agents (iron-oxide or holmium), we propose a post-processing methodology, based on the incorporation of S0 (S at t=0ms) in the fitting algorithm, which is generally applicable for T2* relaxometry and does not increase scan time. Sub-millisecond T2* species introduced by holmium-loaded microspheres in gel and ex vivo rabbit liver were assessed qualitatively and quantitatively using S0-fitting and results were compared to quantitative UTE. S0-fitting is accurate and time efficient and therefore suitable for in vivo studies.

Poster Sessions

250

1420. Modeling the Role of Membrane Permeability and T2 Relaxation TE-Dependent Signal Decay Kevin Harkins1, Jean-Philippe Galons1, Timothy Secomb1, Theodore Trouard1 1University of Arizona, Tucson, USA

The presence of compartmental T2 differences in tissue has been discount due to the experimental measurement of monoexponential T2 decay in tissue. To assess the role of exchange, T2 relaxation and noise on fitting of signal decay, we have developed a finite element model consisting of square cells separated from extracellular space by a permeable membrane. In the presence of physiological membrane permeability and reasonably high SNR, tissues with considerably different T2 relaxation times in the intra and extracellular spaces can exhibit monoexponential behavior.

1421. Determining Precision of Relaxation Time Measurements: Application to T2 Mapping Julien Sénégas1, Clemens Bos2, Hannes Dahnke1 1Philips Research Europe, Hamburg, Germany; 2Philips Medical Systems, Best, Netherlands

Usually, reproducibility of relaxation time mapping is assessed, by comparing relaxation time values across regions of interests in multiple patients. However, generally, little is known on the precision of the individual experiment performed in a specific subject. Here, a maximum likelihood method is presented that calculates a map of the relaxation time standard deviation, from a single mapping experiment, accounting for the noise level of the input images and the sequence parameters. The proposed method was evaluated in simulations and in vivo in T2 mapping of the knee. Knowing the relaxation time standard deviation, the significance of (localized) relaxation time changes over experiments can be more precisely stated.

1422. Evaluation of Parameter Estimation Methods for T2* Relaxometry: A Monte Carlo Approach Matthew T. Latourette1, James E. Siebert1 1Michigan State University, East Lansing, Michigan, USA

T2* relaxometry gains increasing importance with its new clinical role measuring regional iron concentrations for managing iron overload patients. Using Monte Carlo simulations, this study evaluates the performance of five methods for parameter estimation for T2* quantitation from multi-echo gradient echo data. The simulations show that nonlinear least squares fitting of data corrected by SC√|S2-2ς 2| and maximum likelihood estimation provide the most accurate and precise results. Earlier literature R2* values published for clinical decision thresholds can still be used. Caution should be given for results based upon methods with bias and higher variance especially when number of subjects is small.

1423. WAter Saturation Shift Referencing (WASSR) for Chemical Exchange Saturation Transfer Experiments Mina Kim1, 2, Joseph Gillen, 2, Jinyuan Zhou, 2, Peter Christiaan van Zijl, 2 1, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA; 2Kennedy Krieger Institute, Baltimore, Maryland, USA

Chemical exchange saturation transfer (CEST) imaging exploits exchange-based magnetization transfer (MT) between solute and water protons. CEST measurements generally require an asymmetry analysis of the water saturation spectrum (Z-spectrum) with respect to the water frequency, a process exquisitely sensitive to magnetic field inhomogeneities. We show that direct water saturation images acquired with a brief low-power RF saturation pulse can be used to measure the precise water frequency in each voxel, allowing proper centering of Z-spectra independent of spatial B0 variations. After validation in a phantom, the approach is demonstrated in vivo to detect glycogen in human muscle at 3T.

1424. Quantitative MT Measurement - is 3T the Solution or the Problem? Mara Cercignani1, 2, Daniel C. Alexander2, Rebecca S. Samson2, Mark R. Symms2, Gareth J. Barker3 1Fondazione Santa Lucia, Roma, Italy; 2UCL, London, UK; 3Institute of Psychiatry, KCL, London, UK

Here, we address the design of an optimal acquisition protocol for quantitative MT at 3.0T, and assess the performances of this technique at 1.5T and at 3.0T. This involves selecting the most appropriate acquisition parameters, such as TR and flip angle, as well as the optimal sampling scheme, under some field strength dependant constraints. We compare 3 acquisition protocols (2 at 3T and 1 at 1.5T) performing a formal analysis of advantages and limitations of higher field strength using both numerical simulations and real data, in order to determine whether the SNR benefits at 3T outweigh the disadvantages.

1425. Investigating the Dependence of R2* of Whole Blood on Oxygenation, Contrast Agent Concentration and

Magnetic Field Strength Nicholas P. Blockley1, Alexander G. Gardener1, Susan T. Francis1, Penny A. Gowland1 1University of Nottingham, Nottingham, UK

The relaxation properties of blood are key to many functional MRI techniques. The transverse relaxation rate, R2*, is of particular relevance to BOLD

imaging and MR angiography. In this work we investigate the dependence of R2* on the oxygenation and the concentration of ProHance contrast agent in

whole blood. The variation of R2* with contrast agent concentration was non linear. These experiments were performed at field strengths of 1.5T, 3.0T and

7.0T allowing the trends in relaxivity as a function of magnetic field strength to be studied.

1426. Investigating the Dependence of R1 and R2* of Gadofosveset Concentration and Magnetic Field Strength LEI JIANG1, Nicholas Blockley1, Catherine Ludman2, Sue Francis1, Penny Gowland1 1University of Nottingham, Nottingham, UK; 2Nottingham University Hospital NHS Trust, Nottingham, UK

The relaxation properties of blood are key to many MRI techniques. In this work we measure the R1 and R2* relaxivities of a blood pool contrast agent Gadofosveset (Vasovist™, Schering) in whole human blood at 37oC at 1.5 T, 3.0 T, and 7.0 T. We found that the R1 relaxivity reduced with field strength. The R2* relaxivity was non linear, but showed greater sensitivity to contrast agent concentration at higher field strength.

1427. Investigation of Water Diffusion Effect on the Signal Relaxation in Presence of a Stochastic Cylinder Network: A Phantom Study Maja C. Sohlin1, Jan Sedlacik2, Jürgen R. Reichenbach2, Lothar R. Schad3 1German Cancer Research Center, Heidelberg, Germany; 2Friedrich Schiller - University, Jena, Germany; 3Faculty of Medicine Mannheim, University Heidelberg, Germany

A signal decay model valid in the static dephasing regime is commonly used to map the oxygen extraction fraction (OEF) in the brain. In this work, the model was examined in a phantom study under non-static conditions, i.e. small vessel radius. Our measurements show that water diffusion must be taken into account to obtain proper OEF values for small vessel diameters. Both methods become unstable when more than two fit parameters are used, this can be a severe problem in vivo. Furthermore, using T2 as a fit parameter in the static model seems to give misleading results.

Poster Sessions

251

1428. Tissue (Brain) Water Longitudinal Relaxation is Biexponential Andrew M. Prantner1, G L. Bretthorst, Jeffry J. Neil, Joel R. Garbow, Joseph J H Ackerman 1Washington University in St Louis, St Louis, Missouri, USA

Longitudinal relaxation rates in vivo are typically modeled as a monoexponential function because few TI values are collected. When the number of TI values is increased, multiple R1 components can be resolved in peripheral nerve but not in brain gray matter. High-resolution IR data on in vivo rat brain using either 64 or 128 exponentially spaced TI values indicates that there is a ubiquitous distribution of voxels in rat brain gray matter that are best modeled as a biexponential function because of magnetization transfer.

1429. Fast Quantitative T2* Mapping with Elimination of Macroscopic Susceptibility Artifacts

Yu-Guang Meng1, Hao Lei1 1Wuhan Institute of Physics and Mathematics, Chinese Academy of Science, Wuhan, People's Republic of China

In this work, a novel fast z-shimming method was proposed to acquire quantitative T2* maps in the presence of macroscopic susceptibility artifacts. The

method is based on acquisition of two gradient-echo images in the same scan, one at very short echo time without compensation and the other at long echo time but with compensation for in-slice field inhomogeneities. The feasibility of the method was demonstrated in vivo.

1430. Evidence of Multiexponential T2 in Rat Glioblastoma Richard D. Dortch1, 2, Thomas E. Yankeelov1, Mark D. Does1 1Vanderbilt University, Nashville, Tennessee, USA

Multiexponential T2 (MET2) analysis is capable of decomposing bulk NMR signal into components that represent underlying tissue compartments. The goal of this preliminary study was to determine whether MET2 analysis could be applied in a rat glioblastoma tumor model in vivo. Results showed tumor signal to be biexponential, with a short-T2 component (16 ± 12 ms) representing 6 ± 8 % of the signal and a long-T2 component (75 ± 12 ms) representing the remaining signal fraction. Thus, MET2 holds promise as a non-invasive tool for characterizing tumor microenvironment in vivo.

1431. Multi-Channel Line-Sharing for Rapid T1 Mapping: Application to TAPIR Nadim Jon Shah1, Irtiza Ali Gilani1, Heiko Neeb1, A M. Oros-Peusquens1 1Institute of Neurosciences and Biophysics (Medicine), Research Centre Jülich, Jülich, Germany

Measurement of the spin-lattice relaxation time constant, T1, can provide important insights into pathological processes in the human brain such as multiple sclerosis or hepatic encephalopathy. Acquisition times, however, tend to be long and therefore reductions through line sharing are desirable. TAPIR, a Look-Locker based multislice, multishot sequence for rapid T1 mapping is capable in vivo quantification with high spatial resolution by interleaving the slices and time-points. The objective of this work is to accelerate TAPIR using a multi-channel, line-sharing method which acquires sufficient k-space data for high quality T1 mapping. The method is generally applicable to relaxation time mapping.

1432. Iterative Reconstruction for R2 Mapping Based on Radial Fast Spin-Echo MRI Kai Tobias Block1, Martin Uecker1, Jens Frahm1 1Biomedizinische NMR Forschungs GmbH, Goettingen, Germany

The present work describes a novel reconstruction method for radial fast spin-echo MRI which obtains a spin-density and relaxivity map directly from the measured data without calculating intermediate images. This allows for an efficient T2 quantification from a single radial data set. The method is based on an inverse formulation of the problem and involves a modeling of the received MRI signal. Because a solution is found by a numerical optimization procedure, the approach makes optimal use of all data acquired. Experimental data for the human brain in vivo is presented to demonstrate the feasibility of the method.

1433. A Simple Noise Correction for Rapid T1 Measurements Carl Ganter1, Rene Botnar2, Marcus Settles1 1Technical University Munich, Munich, Germany; 2King’s College London, London, UK

Rapid T1 measurements like Look-Locker or IR-TrueFISP are very susceptible to low SNR values, especially near the zero-crossing of the magnetization. But even for very low SNR, reliable results can still be obtained, if the measured signal is fitted against its expectation value according to the Rician distribution, using noise a additional fit parameter. This is particularly helpful, when noise is not easily accessible in the experiment, e.g. if parallel imaging is used.

1434. Between Session Reproducibility and Between Subject Variability of Absolute T1 Jan Scholz1, Heidi Johansen-Berg2, Sean Deoni2 1FMRIB Centre, Oxford, UK; 2FMRIB Centre, UK

T1 relaxation times provide quantitative assessment of pathology and have the potential to provide a measure of structural changes due to disease, recovery or learning. We acquired high-resolution whole-brain quantitative T1 maps with the DESPOT1 protocol in multiple subjects on several occasions to access the intra- and inter-session reproducibility of T1 measurements. These values will be useful to determine power and sample size required to detect changes in T1 values over time. In combination with other markers of structural properties these T1-maps might help to elucidate the processes underlying structural changes in the human brain.

1435. A Multiple Species Separation Method Based on T1 Dehe Weng1, 2 11Siemens Mindit Magnetic Resonance Ltd, Shenzhen, People's Republic of China; 2Institute of Biophysics, Chinese Academy of Sciences, Beijing, People's Republic of China

Introduction New technique for multiple species separation based on T1 was introducedMethod Description theory of this methodResult Separation result images with phantomDiscussion Advantage and disadvantage of new technique

Poster Sessions

252

1436. Accelerated T1 Mapping for Brain MRI Perfusion Quantification Jessy J. Mouannes1, Wanyong Shin2, Maulin Shah1, Timothy J. Carroll1 1Northwestern University, Chicago, USA; 2National Institute of Health, Bethesda, USA

An accelerated method for brain T1 mapping before and after contrast agent injection for MR perfusion quantification is presented, which has the potential to substitute for the conventional, time-consuming T1 mapping technique that applies least square fitting to compute T1 value for each voxel. By including this new method in our fully automatic reconstruction chain for cerebral blood flow and cerebral blood volume quantification using the Bookend technique, we can facilitate the widespread dissemination of this technique and its clinical use.

New Contrast Mechanisms Hall D Tuesday 13:30-15:30

1437. Temperature Mapping of Mouse Brain Tissue Using MRI-PARACEST Contrast Agents Alex Xuexin Li1, 2, Mojmir Suchy, 12, Craig K. Jones1, Ravi S. Menon1, 2, Robert H.E. Hudson2, Robert Bartha1, 2 1Robarts Research Institute, London, Canada; 2The University of Western Ontario, London, Canada

The linear relationship between temperature and bound water chemical shift of MRI-PARACEST contrast agent might be used to measure temperature in-vivo. Temperature maps with standard deviations <1 C were acquired at 9.4 Tesla in phantoms containing A) an aqueous solution of 10 mM Eu3+-DOTAM-Gly-Phe, B) 5% bovine serum albumin with 15 mM Eu3+-DOTAM-Gly-Phe, and C) mouse brain tissue with 4 mM Eu3+-DOTAM-Gly-Phe.

1438. Modulated CEST, Using Cross-Correlation to Measure the CEST Effect Thijs Hendrix1, 2, Klaas Nicolay1, Rolf Lamerichs2 1Eindhoven University of Technology, Eindhoven, Netherlands; 2Philips Research, Eindhoven, Netherlands

A new method is presented to asses the CEST effect. This modulated CEST uses the correlation between the signal change and the RF saturation paradigm. The advantages are that it can be executed real-time. The correlation method will detect the CEST contrast more reliably than averaging when additional signal changes occur, caused by motion or flow artefacts.

1439. CEST in the Presence of MT Kimberly L. Desmond1, Greg Jan Stanisz1, 2 1University of Toronto, Toronto, Canada; 2Sunnybrook Health Sciences Centre, Toronto, Canada

This work explores the validity of the assumption that chemical exchange saturation transfer (CEST) and magnetization transfer (MT) effects are decoupled, with relevance to in-vivo applications involving amide proton transfer (APT) and PARACEST contrast agents. We compared the results of a two-pool compartmental model containing only a CEST component, to a three-pool model which also included MT parameters. It was found that a description of the CEST effect in terms of asymmetry alone may result in its underestimation in the presence of MT, leading to errors in the calculation of physiological quantities including pH and solute concentration.

1440. Optimized Contrast for On-Resonance Proton Exchange Processes of MRI-PARACEST Agents in Biological Systems Alex Xuexin Li1, 2, Craig K. Jones1, Mojmir Suchy, 12, Ravi S. Menon1, 2, Robert H.E. Hudson2, Robert Bartha1, 2 1Robarts Research Institute, London, Canada; 2The University of Western Ontario, London, Canada

A four-pool model based on the modified Bloch equations with exchange terms for the proton exchange processes of a PARACEST agent in biological systems was used to predict the optimal saturation pulse duration for maximum on-resonance PARACEST contrast in-vivo. This predication was verified experimentally by imaging aqueous and bovine serum albumin (BSA) phantoms containing Tm3+-DOTAM-Gly-Lys.

1441. Evaluation of Hyperoxic Gas Induced δR1 and δR2* as MRI Biomarkers of Tissue Oxygenation Status in Human Subjects James P B O'Connor1, 2, Josephine H. Naish1, David L. Buckley1, Alan Jackson1, John C. Waterton1, 3, Yvonne Watson1, Giovanni A. Buonaccorsi1, Deirdre M. McGrath1, Sue Cheung1, Samantha J. Mills1, Gordon C. Jayson2, Geoffrey J M Parker1 1University of Manchester, Manchester, UK; 2Christie Hospital NHS Trust, Manchester, UK; 3AstraZeneca, Macclesfield, UK

Differences in tissue longitudinal relaxation rate (R1) and effective transverse relaxation rate (R2*), induced 100 % oxygen and carbogen inhalation were evaluated in ten healthy subjects. Significant reductions in R1 were demonstrated in spleen, liver and renal cortex, following oxygen and carbogen inhalation. Significant increase in R2* was observed in all organs following carbogen inhalation, an opposite effect to that observed in many studies of tumour pathophysiology. R2* was not changed by breathing 100 % oxygen. The R1 and R2* changes represent distinct but complementary mechanisms of tissue contrast and this study offers further insight into their physiological mechanisms.

1442. Water Diffusion and Magnetization Transfer in Normal and Pathologic Lumbar Disc Meritxell Garcia1, Thomas Egelhof2, Klaus Scheffler3, Oliver Bieri3 1University Hospital Erlangen, Erlangen, Germany; 2University Hospital Basel, Switzerland; 3University of Basel, Switzerland

Diffusion has been shown to be sensitive to intervertebral disc degeneration and pathologies but quantification is often hampered by global motion and susceptibilities. In this work, we investigate possible correlations between the magnetization transfer ratio (MTR) imaging and apparent diffusion constamts (ADC) to yield a possible alternative characterization method of disc diseases that relate to diffusion. ADC and MTR is compared between normal appearing discs of young healthy volunteers and patients. High correlations between MTR and ADC values were found suggesting that changes in water diffusion for intervertebral discs are also reflected in MT measurements.

Poster Sessions

253

1443. Delta Relaxivity Enhanced MR (DreMR): Theory of T1-Slope Weighted Contrast Jamu K. Alford1, Brian K. Rutt2, Timothy J. Scholl1, William B. Handler1, Blaine A. Chronik1 1The University of Western Ontario, London, Canada; 2Robarts Research Institute, London, Canada

Delta relaxivity enhanced MR (dreMR) is a novel MR method for producing image contrasts related to the magnetic field dependence of tissue relaxation rates. Applications include cellular/molecular MRI, where dreMR may significantly increase the detection sensitivity/specificity to in-vivo target molecules. Molecular specificity is obtained by accessing the dramatic change in relaxivity slope, seen upon molecular binding of activatable contrast agents, as the source of contrast. The dreMR double inversion recovery method as well as the necessary hardware requirements to perform dreMR in a clinical MR scanner will be discussed.

1444. Modulation of Tumour R1: A Novel Biomarker of Oxygenation Status James P B O'Connor1, 2, Alan Jackson1, Giovanni A. Buonaccorsi1, Yvonne Watson1, Sue Cheung1, Gordon C. Jayson2, Geoffrey J. Parker1 1University of Manchester, Manchester, UK; 2Christie Hospital NHS Trust, Manchester, UK

Inhalation of 100% oxygen has been shown to increase normal tissue R1. We describe modulation of tumour R1 in five patients with advanced solid tumours. Significant increase in R1 was measured on oxygen inhalation(p<0.001; group range 0.0087-0.0526 s-1). This suggests that the technique shows promise for producing novel biomarkers of tumour oxygenation status.

1445. Positive-Contrast Imaging of Microscopic Paramagnetic Particles Using Field-Encoded Fluctuating-Equilibrium SSFP William R. Overall1, John M. Pauly1 1Stanford University, Stanford, California , USA

We propose a new technique for positive-contrast visualization of small volumes of paramagnetic agents using fluctuating-equilibrium steady state in conjunction with opposing refocusing gradients. The combination of these two techniques provides better background suppression than either one alone, and the use of a dual-equilibrium steady state allows for concurrent acquisition of an anatomic reference. Detection limits of the technique are explored theoretically and experimentally, and images demonstrate improved detection when compared to previous techniques.

1446. Positive Contrast with Therapeutic Iron Nanoparticles for in Vivo Follow Up at 4.7T Monica Sigovan1, Misara Hamoudeh2, Achraf Al Faraj1, Hatem Fessi2, Emmanuelle Canet-Soulas1 1Université de Lyon, Université Lyon1, Creatis-LRMN, UMR CNRS 5220, U630 INSERM, INSA-Lyon, Lyon, France; 2Université de Lyon, Université Lyon1, LAGEP, UMR CNRS 5007, Lyon, France

Magnetic nanoparticles (MNP) are expected to enable the inclusion of specific drugs in order to combine a therapeutic action to the MRI diagnostic approach. The importance of positive contrast techniques is the improved sensitivity for iron detection compared to standard T2* methods. We report the application of the “white marker” technique at a relatively high field of 4.7 T in a preliminary in vitro and in vivo study using a novel MNP system designed for local therapy. Compared to the standard gradient echo the method shows the ability to discern between high concentrations. The combined negative and positive contrast protocol allowed a good characterisation for the in vivo localization of MNP and their follow up.

1447. Positive Contrast Fe Nano-Particle Imaging of Mouse Brain Vasculature with SWIFT Curtis Andrew Corum1, Geoffrey L. Curran2, Deepali Sachdev1, Djaudat Idiyatullin1, Steen Moeller1, Michael Garwood1 1University of Minnesota, Minneapolis, Minnesota, USA; 2Mayo Clinic College of Medicine, Rochester, Minnesota, USA

We demonstrate initial results with positive contrast enhancement in an in-vivo wild type mouse brain, after bolus I.V. injection(s) of the mono-crystalline ion oxide nano-particle solution1 MION-47. MION-47 has both R1 and R2* relaxivity, but the R2* relaxivity typically dominates at high concentrations and/or high fields.Utilizing SWIFT (SWeep Imaging with Fourier Transform) we show high field, high concentration R1 induced positive T1 contrast at 5mg/kg and 20 mg/kg MION-47 doses.

1448. Visualization of Inhomogeneous Local Magnetic Field Gradient Due to Susceptibility Contrast HyungJoon Cho1, Seungoh Ryu2, Jerry L. Ackerman3, Yi-Qiao Song2 1Memorial Sloan Cancer Center, New York, New York, USA; 2Schlumberger Doll Research, Cambridge, Massachusetts, USA; 3Martinos Center, Department of Radiology, Massachusetts General Hospital, Cambridge, Massachusetts, USA

We visualize inhomogeneous local magnetic field (internal magneticfield) gradient arising from susceptibility contrast between anarray of cylindrical glass tubes (solid matrix) and surroundingwater (pore fluids) in a uniform applied magnetic field. MRIwas performed to determine the spatially resolved decay rates due to diffusion in the internal magneticfield. These rates are shown to be directly proportional to thelocal gradient strength obtained from theoretical calculations. Wealso spatially resolve the interference pattern ofthe cross-terms between internal and external pulsed fieldgradient (PFG) along different PFG orientations and extractcorresponding cross-terms in this model system. This workdemonstrates a simple yet representative case for visualizing thelocal susceptibility induced magnetic fields in porous media.

1449. Combined Positive Contrast and Relaxation in the Rotating Frame for Molecular Imaging of In-Vivo SPIO Labeled Cells Ovidiu Cristian Andronesi1, 2, Dionyssios Mintzopoulos1, 2, Meenu Kesarwani1, Laurence Rahme1, Aria A. Tzika1, 2 1Massachusetts General Hospital and Shriners Burn Hospital, Harvard Medical School, Boston, Massachusetts, USA; 2Athinoula A. Martinos Center for Biomedical Imaging, Boston, Massachusetts, USA

We present a refined MRI method for positive contrast (PC) molecular imaging of superparamagnetic iron-oxide (SPIO) labeled macrophages to visualize infection in-vivo and monitor its progression. Existing negative and positive contrast methods for SPIO detection have difficulties due to quantification and specificity limitations, respectively. We combine existing positive contrast schemes with relaxation in the rotating frame to improve the specificity for SPIO. Our results on phantom, and test and control mice suggest that this combination can be used to fine-tune the level of contrast and to quantify the SPIO and macrophage accumulation at the infection site.

Poster Sessions

254

1450. Novel Detection of Super-Paramagnetic Tracers Using an Off-Resonance Preparation Pulse with Short-Echo-Time Gradient Echo Imaging Sherif R. Fahmy1, Nicole Mascheri1, Tanja Paunesku1, Gayle Woloschak1, Debiao Li1, Todd Parrish1 1Northwestern University, Chicago, Illinois, USA

An off-resonance preparation pulse is used to selectively dephase spins in the vicinity of a super-paramagnetic tracer. Short echo times reduce T2* effects outside of the frequency range being saturated. The signal from background tissue remains intact as compared to positive contrast techniques for tracer detection.

1451. Off-Resonance Projection Imaging of USPIO-Enhanced Bone Marrow Carsten Warmuth1, Michael Reinhardt2, Hanns-Joachim Weinmann2, Robert Krieg1 1Siemens Medical Solutions, Erlangen, Germany; 2Bayer Schering Pharma, Berlin, Germany

Ultrasmall superparamagnetic iron-oxide (USPIO) particles are taken up by healthy bone marrow. With an off-resonance spin echo sequence, projection images of the bone marrow comparable to scintigraphy or X-Ray acquisitions can be obtained.

1452. Assessing the Detection Sensitivity of Iron Loaded Cells in Spoiled Gradient Echo Imaging Xavier Helluy1, Wing Chow2, daniel Haddad1, R Ebert1, M Weber1, P M. Jacob1 1University of Würzburg, Würzburg, Germany; 2University of Toronto, Toronto, Canada

Susceptibility inhomogeneities induced by iron particles affect the magnitude and phase of gradient echo images, facilitating the detection of iron-loaded cells with MR. The goal of this study is to quantify the iron detection sensitivities of spoiled gradient echo magnitude and phase images and evaluate the possible gain in iron detection sensitivity when combining phase and magnitude information. To this end extended statistical analysis of numerical simulations and experimental measurements on iron-loaded cells dispersed in gels have been conducted, and various image filters evaluated.

1453. Application of Positive Contrast SSFP Imaging to USPIO-Labeled Macrophage Cells: Theory and in Vitro Experiment Nicole Mascheri1, Zhuoli Zhang1, Tanja Paunesku1, Gayle Woloschak1, Rohan Dharmakumar1, Debiao Li1 1Northwestern University, Chicago, Illinois, USA

Inflammatory activity in atherosclerotic lesions is an indicator of plaque vulnerability. MRI is capable of detecting inflammation through accumulation of ultrasmall superparamagnetic iron oxide nanoparticles (USPIO) in macrophage cells in the plaque. The purpose of this work was to investigate the application of a recently developed positive contrast imaging method, termed Fast Low-Angle Positive contrast Steady-state free precession (FLAPS) imaging, to USPIO-labeled macrophages at clinical field strength and resolution. The dependence of positive contrast on flip angle and concentration of labeled cells was also evaluated.

1454. Fast Relaxation Induced by SPIO Compromises Contrast from Intermolecular Double–quantum Coherence in CRAZED–MRI Elvira Mehlin1, Stefan Kirsch1, Peter Bachert1 1German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany

The CRAZED sequence permits detection of signal generated by intermolecular double–quantum coherence (iDQC). When applied to 1H MRI, a novel type of contrast is obtained, in particular, a positive contrast when superparamagnetic iron oxide particles (SPIOs) are present. We demonstrate that the high T1–relaxivity of SPIOs can cause spurious signal in CRAZED MRI which cannot be attributed to iDQC.

1455. Improved T2* Based Quantification of Holmium-Loaded Microspheres in Gels and Liver Tissue Using Multiple Gradient Echo Sampling of FID Rather Than SE Signals Peter Roland Seevinck1, Jan-Henry Seppenwoolde1, Jaco Zwanenburg1, Chris J.G. Bakker1 1University Medical Center, Utrecht, Netherlands

Quantitative assessment of the radionuclide biodistribution is of major importance for dosimetry in transcatheter hepatic arterial embolization with radioactive holmium-loaded microspheres (HoMS). In this work, we demonstrate that T2*-based quantification of holmium-loaded microspheres can be done best using multiple gradient echo sampling of FID (MGEFID) rather than SE (MGESE) signals. MGESE caused a severe underestimation of the integral HoMS dose present, specifically at higher concentrations, which can be attributed to the diffusion sensitivity of MGESE, as was shown by in vitro. MGEFID strongly reduced the underestimation of HoMS in ex vivo rabbit livers.

1456. Modeling CPMG Behavior in a Realistic Magnetically-Heterogeneous Tissue Matrix Nilesh R. Ghugre1, 2, John C. Wood1 1Childrens Hospital Los Angeles, Los Angeles, California , USA

R2* and single echo R2 have been successfully calibrated for hepatic iron concentration. Despite several advantages of CPMG sequences, their implementation in quantifying clinical iron burden has been difficult. They are complicated by anomalous non-exponential signal decay characteristics and R2-iron calibrations may also vary with echo spacing τ). We employed a realistic tissue geometry to interrogate the inner mechanisms of CPMG behavior in the presence of magnetic inhomogeneities, via computational modeling. Model-predicted R2τ behavior was consistent with previous findings. Moreover, predicted R2-iron relationships at specified τ were in confirmation with published in vivo calibration curves. A validated computational model will complement existing theoretical predictions in understanding the underlying biophysics of proton-iron interaction in an iron-rich tissue matrix.

Poster Sessions

255

1457. MR Contrast Media at 7Tesla - Preliminary Study on Relaxivities Iris M. Noebauer-Huhmann1, Oliver Kraff2, Vladimir Juras1, Pavol Szomolanyi1, 3, Stefan Maderwald2, Vladimir Mlynarik4, Jens M. Thyesohn2, Susanne C. Ladd2, Mark E. Ladd2, Siegfried Trattnig1 1MR Centre - Highfield MR, Vienna, Austria; 2Erwin L.Hahn Institute for MRI, Essen, Germany; 3Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia; 4EPFL / LIFMET, Lausanne, Switzerland

Contrast media are a powerful tool to improve the diagnostic value of MRI. The relaxivities have been determined for the routinely used magnetic field strengths 1.5T and 3T. Recently, 7 Tesla magnets have been introduced for whole body imaging. In preliminary calculations, the relaxivities r1 and r2 in physiologic saline soluton at 37 C were lower at 7 Tesla than has been described in the literature for lower field strengths. The values decrease with higher contrast agents concentrations. The values for blood were also calculated. The different r1 and r2 relaxivities at 7 Tesla have to be taken into account.

1458. Optimization of Parameters for the Distant Dipolar Field Signal Acquired in CRAZED-Multiecho Pulse Sequence Chung Ki K. Wong1, Jianhui Zhong1 1University of Rochester, Rochester, New York, USA

The decrease of dipolar signal with refocusing pulses of finite duration in a CRAZED-multiecho acquisition was investigated previously. It was found that the rephasing of the dipolar signal during the refocusing pulses in the multiecho sequence depends substantially on the phase of the pulses. In this abstract, the total signal acquired from the multiecho sequence was optimized with the parameters of the sequence. The results show that the attenuation of the signal due to the finite duration of the refocusing pulses can be compensated with a longer τ2 and a proper choice of the phase of the pulses.

1459. Cross-Relaxation in Methacrylic Acid-Based Dosimetry Gels Heather Marie Whitney1, Jim Joers1, John C. Gore1 1Vanderbilt University, Nashville, Tennessee, USA

Radiation dose distributions can be quantified using MRI of irradiated polymer gels The dose response mechanism responsible is believed to involve magnetization exchange between polymer protons and the bulk water in the gel. This study seeks to quantify the contributions of chemical exchange or dipolar cross-relaxation to the dose response mechanism in methacrylic acid-type polymer gels through studies of relaxation properties of the monomers present in the gel system. The results show that dipolar cross-relaxation between water and methacrylic acid monomer may contribute to relaxation through magnetization transfer between the methyl proton and water and one methylene proton and water.

1460. Synthesis and Physicochemical Characterization of a New Gd Complex and Its Eu Analogue, Suitable Bimodal Contrast Agents for MRI and Optical Imaging Sophie Laurent1, Luce Vander Elst1, Mélanie Wautier1, Chantal Galaup2, Claude Picard2, Robert Muller1 1University of Mons-Hainaut, Mons, Belgium; 2Université Paul Sabatier, Toulouse, France

The lanthanide complexes of the PMN-tetraacetic acid present thus interesting properties both for MRI and for optical imaging. In fact the Ln-complexes have a relatively good stability in physiological environment. The Gd-complex has a high proton relaxivity and a value of tM which approaches the optimal value required to obtain high relaxivity once the chelate is bioconjugated to macromolecules. Moreover, an efficient energy transfer from the pyridine to the metal occurs in the Eu-complex and the luminescence lifetime of the complex is long enough to avoid the overlapping with biological background.

1461. Compliance Weighted Imaging in MR Elastography ingolf sack1, Eberhard Siebert1, Uwe Hamhaber1, Dieter Klatt1, Sebastian Papazoglou1, Jürgen Braun1 1Charité - University Medicine Berlin, Berlin, Germany

Compliance weighted imaging (CWI) is introduced that uses ultra-low frequency mechanical excitation. As a result, viscous damping is negligible which allows the approximation of a constant strain-energy averaged over one oscillation period. Using first-derivative data-processing yields a new contrast that is scaled by the inverse stiffness (compliance) of the material. The spatial resolution in CWI-MRE is comparable to that of standard MR images which considerably improves the detail resolution in MRE. CWI-MRE allows mapping the anatomical structure of the brain based on its mechanical properties. The method can further be used to examine mechanical properties of pathologic tissue.

Motion Correction Hall D Wednesday 13:30-15:30

1462. Inverse Interpolation Algorithm for Retrospective Motion Correction in Interleaved Images Torsten Rohlfing1, Martin H. Rademacher1, Adolf Pfefferbaum1 1SRI International, Menlo Park, California , USA

Patient motion between passes of an interleaved image acquisition makes the resulting image stack unusable for 3D image analysis. This paper introduces an algorithm for retrospective correction of characteristic interleaved motion artifacts. The correction is cast as an image reconstruction problem, which is solved by an inverse interpolation algorithm.

1463. Spectral Selective Pencil-Beam Navigator for Abdominal Imaging Max Köhler1, Chrit Moonen2, Mario Ries2 1Philips Medical Systems, Finland; 2IMF, CNRS / Univ. Bordeaux2, Bordeaux, France

A spectral selective pencil-beam navigator is presented, which is based on a 121-binomial pulse train of 2D-selective pulses. The beam allows robust real-time slice tracking of abdominal organs without interference with water-selective MR-imaging.

Poster Sessions

256

1464. Parallel Imaging PROPELLER with Across-Blade Calibration: In Vivo Results Philip James Beatty1, Zhiqiang Li2, Zachary William Slavens3, Anja C. S. Brau1 1GE Healthcare, Menlo Park, California , USA; 2GE Healthcare, Phoenix, Arizona , USA; 3GE Healthcare, Waukesha, Wisconsin, USA

Parallel imaging PROPELLER with across-blade calibration supplements intra-blade calibration with an external "calibration blade". This allows the number of calibration phase encodes acquired with each accelerated blade to be minimized, increasing the net acceleration factor. Using in vivo acquisitions performed during subject motion, it is demonstrated that the across-blade approach is resilient to motion. This study used an acceleration factor of three with two additional calibration phase encodes on each accelerated blade; combined with an echo-train length of 24, this resulting in a net acceleration factor of 2.67 per accelerated blade.

1465. Decoupling Motion Navigation from Imaging Using Spatial-Spectral RF Pulses Andre J. W. van der Kouwe1, Thomas Benner1, Lawrence L. Wald1 1Massachusetts General Hospital, Charlestown, Massachusetts, USA

Cloverleaf navigators can be used for real-time motion correction of anatomy that moves as a single rigid body. The technique requires that the signal for imaging and navigation come from the same slab and that the magnetization be kept in steady-state. These requirements may be relaxed by separately exciting fat for the navigation and water for imaging. The utility of cloverleaf navigator motion correction may thus be expanded to include imaging techniques such as clinical 2D fast spin echo and DTI. The principle of decoupling imaging and navigation is shown for translational motions in a phantom and human volunteer.

1466. Navigator Gated Imaging with Phase Based Edge Detection Kenichi Kanda1, Yuji Iwadate1, Aki Yamazaki1, Tetsuji Tsukamoto1, Susumu Kosugi1 1GE Yokogawa Medical Systems, Hino, Japan

In navigator echo technique, accurate position detection of the diaphragm is essential. As most algorithms rely on the magnitude of the navigator spatial profile, they have some difficulties in the accurate detection when the navigator tracker is partially saturated by the RF pulse of the imaging sequence. We propose a new navigator algorithm that uses the phase profile of navigator echo data to improve the accuracy of the position detection even with the saturation effect. Our results show that the phase based algorithm is feasible and can be used in the navigator gated imaging to reduce motion artifacts.

1467. Head Movement Correction for MRI with a Single Camera Lei Qin1, 2, Peter van Gelderen1, Jacco de Zwart1, Fenghua Jin2, Yang Tao2, Jeff H. Duyn1 1AMRI, LFMI,NINDS,National Institutes of Health, Bethesda, Maryland, USA; 2University of Maryland, College Park, Maryland, USA

We propose a new motion correction method for MRI using single camera that does not require calibration. A short training scan is required to relate the camera images to motion parameters derived from concurrently acquired EPI data. With this information, motion during an actual MRI scan with arbitrary pulse sequence is estimated by matching each newly captured camera image with one or more images from the training data. The average motion parameters of these training images served as motion estimate for that new image. Initial results show an overall accuracy of better than 0.3 mm translation and 0.3° rotation.

1468. Navigator Echo Analysis Hybridizing Magnitude and Phase Edge Detection Yuji Iwadate1, Kenichi Kanda1, Aki Yamazaki1, Susumu Kosugi1, Tetsuji Tsukamoto1 1GE Yokogawa Medical Systems, Hino, Japan

Applicability of navigator echo is limited to the series where the main sequence FOV is distant from the navigator position, due to interference of RF pulses. We developed a hybrid algorithm utilizing both magnitude and phase information to detect the diaphragm position robustly. The proposed method could detect the diaphragm position correctly without RF interference affection. This method can be used to improve the abdominal image quality of the patients who have difficulty in breath hold.

1469. Spiral Projection Imaging Motion Correction Using Lines of Intersection Ken O. Johnson1, James G. Pipe1 1Barrow Neurological Institute, Phoenix, Arizona , USA

In Spiral Projection Imaging, planes of data are collected to fill a sphere in k-space. Every plane intersects every other plane on a line. Therefore, any two planes can be compared, to determine which line from each plane is common between them. Planar orientations can then be deduced, that are consistent with the calculated lines of intersection.

1470. In-Plane Estimation Based Motion Correction for Spiral Projection Imaging Ryan K. Robison1, Eric Aboussouan1, James G. Pipe1 1Barrow Neurological Institute, Phoenix, USA

Prior studies have asserted the potential of SPI (Spiral Projection Imaging) to accomplish 3D self-navigated motion estimation and correction. The goal of this study was to verify the capability of SPI to correct for three degrees of rotational motion. Through the application of an in-plane estimation based correction algorithm to simulated SPI data, it was determined that SPI is capable of producing a motion corrected 3D data set.

Poster Sessions

257

1471. Self-Navigated Motion Compensation in Simultaneous 19F/1H 3D Radial Imaging Using Golden Means Profile Interleaving Juergen Rahmer1, Jochen Keupp1, Shelton D. Caruthers2, 3 1Philips Research Europe, Hamburg, Germany; 2Washington University, St. Louis, Missouri, USA; 3Philips Medical Systems, Andover, Massachusetts, USA

MR detection of low concentrations of imaging agents labeled with 19F often requires long signal averaging times and therefore motion compensation is desirable. Simultaneous acquisition of 1H and 19F signal allows self-navigated motion tracking using the stronger 1H signal. In this work, 3D isotropic radial imaging has been combined with a profile acquisition order based on the 2D golden means. Thereby, the intrinsic robustness of radial sequences against motion and undersampling can be combined with a flexible, motion-adaptive temporal frame rate. The technique is demonstrated in 19F/1H in-vivo scans with 1D translational motion and phantom scans with 3D rigid-body motion.

1472. k-Space Sampling for Motion Correction with Parallel Imaging Techniques Philip Martyn Robson1, Aaron K. Grant1, David C. Alsop1 1Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA

Motion related artifacts are a common cause of image corruption in MRI. For many protocols, even speeding image acquisition with parallel imaging is not sufficient to freeze motion. Rigid body motion can be detected with a variety of MRI and non MRI methods, and potentially used to correct for motion during reconstruction. However, the ability to faithfully reconstruct a motion corrected image depends upon the chosen k-space trajectory, the number of receive coils employed, and the time dependence of the motion. We implemented a general least squares reconstruction algorithm for motion correction using all redundant information in the receive coils. In simulated data, occasional, sudden translation and rotation can be fully corrected if a suitable k-space acquisition order is employed.

1473. Automatic Motion Correction of FSE Wrist Exams: Towards Full Clinical Implementation Armando Manduca1, David S. Lake1, Heidi A. Ward1, Jie Liang1, Lauren C. Edge1, Scott O. Stiving1, Natalia Khaylova1 1Mayo Clinic, Rochester, Minnesota, USA

Fully automatic translational motion correction of high resolution FSE wrist exams, based on optimization of an image quality measure, was tested on all FSE wrist exams acquired on a clinical scanner over a 3 month period. Motion correction was automatically performed on all exams in an average time of 1 min 51 sec. 44% of the 160 series acquired were judged to have some sign of motion, and 91% of these were improved to some degree. A separate study in which the corrected exams are returned to the scanner and evaluated by radiologists is now under way.

1474. Extraction of Abdominal Motion for Molecular Imaging Frederik J. de Bruijn1, Munibe Simsek-Yildirim, 12, Aart J. Nederveen3, Muhammed Yildirim1, 4, Andre M.J. Sprengers3, Jaap Stoker3, Rolf M.J.N. Lamerichs1 1Philips Research, Eindhoven, Netherlands; 2Gebze Institute of Technology, Gebze, Turkey; 3Academic Medical Center, Amsterdam, Netherlands; 4Eindhoven University of Technology, Eindhoven, Netherlands

MRI of the human bowel is generally complicated due to its motility and due to the intrinsically weak and often ambiguous tissue contrast. We present a method to extract colon motion from volumetric time sequences without the need for extensive bowel preparation. The method combines the use of chemical-shift induced tissue features with a recursive spatiotemporal method to generate spatially consistent motion patterns without the use of prior tissue-segmentation and -modelling. Its application is discussed to motion-corrected signal accumulation of 19F-based targeted contrast agents.

1475. Motion Insensitive 3D T2 and T1-Weighted Imaging with a Real-Time, Image-Based PROspective MOtion Correction Technique (3D PROMO) and Automated Re-Acquisition of Motion-Corrupted K-Space Segments Ajit Shankaranarayanan1, Eric Han1, Cooper Roddey2, Nate White2, Reed Busse3, Joshua Kuperman2, Juan Santos4, Dan Rettmann5, Ehud Schmidt6, Anders Dale2 1GE Healthcare, Menlo Park, California , USA; 2UCSD, San Diego, California , USA; 3GE Healthcare, Madison, Wisconsin, USA; 4Stanford University, Palo Alto, California , USA; 5GE Healthcare, Rochester, USA; 6GE Healthcare, Boston, Massachusetts, USA

A complete motion correction solution for 3D imaging has been presented here. The real time image-based 3D PROspective MOtion correction method (3D PROMO) previously presented has been integrated with a 3D T2-weighted imaging sequence (3D FSE acquisition) as well as a 3D T1 weighted imaging sequence (3D IR-SPGR acquisition.). In addition, an automated re-acquisition of left over motion-corrupted k-space views to further increase the robustness of PROMO has been described. In vivo scans demonstrate the efficacy of both 3D T2w and T1w PROMO in presence of motion.

1476. Motion Insensitive Imaging Using 3D PROspective MOtion (PROMO) Correction with Region-Of-Interest Tracking John Cooper Roddey1, Ajit Shankaranarayanan, Eric Han, Nathan White, Anders M. Dale 1University of California, San Diego, La Jolla, California , USA

A region-of-interest (brain) in navigator images is automatically specified and tracked. Regions within the navigator FOV that move non-rigidly relative to the ROI are effectively ignored during tracking. Motion insensitive 3D MR images are acquired.

Poster Sessions

258

Compressed Sensing Hall D Thursday 13:30-15:30

1477. Suppression of MRI Truncation Artifacts Using Total Variation Constrained Data Extrapolation Kai Tobias Block1, Martin Uecker1, Jens Frahm1 1Biomedizinische NMR Forschungs GmbH, Goettingen, Germany

Finite sampling of k-space causes ringing artifacts from signal truncation at the border of the measured k-space. This work demonstrates that the simple assumption of a piecewise-constant object can be exploited to extrapolate the data in k-space beyond the measured part. The assumption translates into a total variation minimization problem which can be solved with a non-linear optimization algorithm and allows for a significant reduction of truncation artifacts without compromising resolution. In the presence of substantial noise, a modified approach offers edge-preserving denoising which, in addition to supplementing data, also tolerates slight deviations from the measured data.

1478. Compressed Sensing Parallel Imaging Chen Zhao1, Tao Lang1, Jim Ji1 1Texas A&M University, College Station, USA

Both parallel MR Imaging (pMRI) and compressed sensing (CS) can significantly reduce image acquisition time in MRI, the former by utilizing multi-channel receivers and the latter by utilizing the sparsity of MR images in a transformed domain. An integrated approach was developed to use CS as a regularization tool to improve the pMRI reconstruction. Reconstruction results from in-vivo data show that CS can significantly suppress the aliasing artifacts and improve SNR, but with very minor resolution loss. Comparison with the truncated SVD and the Tikhonov regularization were presented.

1479. Nonlinear Inversion with L1-Wavelet Regularization – Application to Autocalibrated Parallel Imaging Martin Uecker1, Kai Tobias Block1, Jens Frahm1 1Biomedizinische NMR Forschungs GmbH am MPI für biophysikalische Chemie, Goettingen, Germany

Recent algorithms for autocalibrated parallel imaging estimate the coil sensitivities and the image at the same time. Regularization is commonly employed to counteract the low SNR due to the reconstruction process (quantified by the g-factor map). In contrast to linear reconstruction methods which are restricted to a regularization related to the L2-norm of the image, nonlinear regularization methods like the L1-norm in combination with a sparsity transform or total variation are known to suppress noise much more efficiently. This work demonstrates how L1-wavelet regularization can be incorporated into an autocalibrating parallel imaging algorithm based on a regularized nonlinear inversion method.

1480. Applying Compressed Sensing in Parallel MRI Bing Wu1, Rick P. Millane1, Richard Watts1, Philip Bones1 1University of Canterbury, Christchurch, New Zealand

Compressed sensing is used in recovering images from multiple receiver coil data sets, and the results are compared to those obtained from using a direct image recovery method (SENSE). It is shown that compressed sensing achieved better reconstruction results than the conventional SENSE approach at high acceleration factors, since the latter suffers badly from deteriorated SNR.

1481. Accelerating Dynamic Contrast-Enhanced MRI Using Compressed Sensing Tao Lang1, Jim Ji1 1Texas A&M University, College Station, USA

Compressed Sensing (CS) is an effective approach to fast imaging by utilizing the signal sparsity in a transformed domain. We developed a CS imaging method for dynamic contrast enhanced MRI. Specifically, a difference operator is applied to the successive temporal data frames to enhance the spatial signal sparsity for CS reconstruction. The new algorithm method is assessed using simulated and in-vivo dynamic imaging data. The result shows that the new method provides higher resolution than zero-padded Fourier reconstruction and the Keyhole method, and it results in reduced artifacts and noise than conventional CS reconstruction where no temporal information is used.

1482. Interventional MRI with Sparse Sampling: An Application of Compressed Sensing Diego Hernando1, Justin Haldar1, Leslie Ying2, Kevin King3, Dan Xu3, Zhi-Pei Liang1 1University of Illinois at Urbana-Champaign, Urbana, Illinois, USA; 2University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA; 3G.E. Medical Systems, Milwaukee, Wisconsin, USA

Interventional MRI (I-MRI) is an important dynamic imaging application, allowing the guidance of therapeutic procedures, which requires high frame-rate and near-real-time reconstruction. Compressed sensing (CS) allows high-resolution reconstruction from a reduced number of samples by exploiting the sparsity of the signal. In this work, CS is tailored to ¡ maximize¡± the sparsity in each frame while satisfying the inherent causality constraints in I-MRI reconstruction, so that high-quality images can be obtained from a small number of samples.

1483. Prior Information Constraint Compressed Sensing (PICCS): A Novel Technique for MR Myocardial Perfusion Imaging Orhan Unal1, 2, Jie Tang1, Guang-Hong Chen1 1University of Wisconsin, Madison, Wisconsin, USA

Recently, a novel reconstruction technique called PICCS (Prior Information Constraint Compressed Sensing) has been developed. This technique enables accurate reconstruction of high SNR images with large undersampling factors (>50 in 2D). In this work, PICCS and its utility in MR perfusion imaging is investigated. In PICCS, the sparsity of the difference image between the target image and the high SNR prior image is exploited. When this PICCS sparsity is combined with other known sparsifying transforms such as total variation (TV) norm used in compressed sensing (CS), PICCS enables accurate reconstruction of images using fewer projections than required by CS and standard filtered backprojection (FBP) reconstruction

Poster Sessions

259

1484. MRI with Accelerated Multi-Coil Compressed Sensing Luca Marinelli1, Christopher J. Hardy1, Daniel J. Blezek1, 2 1General Electric, Niskayuna, USA; 2Mayo Foundation and Clinic, Rochester, USA

Parallel imaging methods reduce acquisition time at the expense of aliasing artifacts and image SNR. Compressed sensing has emerged as a framework for exact reconstruction for compressible signals and images. A novel approach is proposed to adapt distributed compressed sensing algorithms to accelerated multi-coil MR imaging. The algorithm employs coil sensitivity maps and can be combined with parallel imaging to achieve high acceleration factors. We demonstrate the convergence properties of the method on a numerical phantom and apply it to FGRE imaging.

1485. Superresolution Parallel Magnetic Resonance Imaging Ricardo Otazo1, Fa-Hsuan Lin2, Graham Wiggins2, Ramiro Jordan1, Stefan Posse1 1University of New Mexico, Albuquerque, New Mexico, USA; 2Massachusetts General Hospital, Boston, Massachusetts, USA

Parallel MRI reconstruction is formulated as a superresolution problem where acceleration is performed by acquiring the low spatial resolution representation of the object being imaged and coil sensitivity maps are acquired with higher target spatial resolution. The increase in spatial resolution will be determined by the degree of sensitivity variation within the low resolution voxel. The method is applicable to receiver arrays with a large number of small elements which provide strong spatial variation of the coil sensitivity maps. Superresolution Sensitivity-Encoding (SURE-SENSE) represents a powerful alternative to standard SENSE for the same acquisition time and it is advantageous for low spatial resolution where the aliasing from intra-voxel coil sensitivity variation is removed. We show feasibility of the method for human brain imaging using receiver arrays with 32 and 96 elements.

1486. An Experimental Comparison of Super-Resolution Techniques in 2-D Multi-Slice MRI Richard Z. Shilling1, Marijn E. Brummer2 1Georgia Insitute of Technology, Atlanta, Georgia, USA; 2Emory University, Atlanta, Georgia, USA

Most super-resolution reconstruction (SRR) techniques proposed for MRI to date have involved multiple multi-slice acquisitions with sub-pixel shifts in the slice-selection or phase-encoding direction. Another SRR technique has been developed called “Multi-stack” (MS), which instead of using sets of parallel shifted scans (PS), uses multiple multi-slice stacks of the same object, scanned at different orientations, rotated about the frequency-encoding axis. In this work we compare these methods with a real scanning experiment using 2-D Inversion Recovery acquisition.

1487. Introduction of a Nonconvex Compressed Sensing Algorithm for MR Imaging André Fischer1, 2, Felix Breuer2, Martin Blaimer2, Nicole Seiberlich1, Peter Michael Jakob1, 2 1University of Wuerzburg, Wuerzburg, Germany; 2Research Center for Magnetic Resonance Bavaria e.V., Wuerzburg, Germany

In recently published works, convex optimization procedures were chosen for recovering missing data with Compressed Sensing (CS). This method depends on a proper adjustment of parameters in the functional to be optimized; this is often computationally expensive and reduces the advantage of accelerated data acquisition. In this work, a CS reconstruction algorithm based on a nonconvex procedure is introduced for MR imaging. No parameter determination is necessary, thus reducing the computational load. A preliminary application in the field of MR is shown, as well as a demonstration which indicates that the nonconvex technique offers similar results as a convex optimization.

1488. Combining Compressed Sensing and Parallel Imaging Kevin F. King1 1GE Healthcare, Waukesha, Wisconsin, USA

Compressed sensing uses L1-norm minimization in a sparse transform space to reconstruct randomly undersampled k-space data. Parallel imaging uses L2-norm error minimization to incorporate receive B1 information into the reconstruction of undersampled multicoil k-space data. An L1-norm penalty function has also been used for denoising and regularization of parallel imaging and non-Cartesian k-space reconstructions. These methods are overlapping and complimentary and can be combined by reconstructing randomly undersampled multicoil k-space data with both L1- and L2-norm minimization. This combines compressed sensing and L1-regularized parallel imaging and denoises the image. The resulting acceleration can be higher than with either technique alone.

1489. Data Interpolation in Phase-Scrambling Fourier Transform Technique by Modified Gerchberg's Algorithm for Alias-Free Image Reconstruction Yoshifumi Yamada1, Satoshi Ito1 1Utsunomiya University, Utsunomiya, Japan

This report presents a novel data interpolation method in the phase-scrambling Fourier transform (PSFT) imaging technique. A coarsely sampled PSFT signal which an aliasing artifact is produced in the reconstructed image can be interpolated to obtain fully encoded signal by using an iteration method based on the Gerchberg's algorithm known as a super resolution technique. Modification of the Gerchberg's algorithm is made to apply the method to interpolation of PSFT signal. Numerical simulation using MR images shows that alias-free images are reconstructed from the interpolated PSFT signal by using this technique.

Image Reconstruction Hall D Monday 14:00-16:00

1490. Rapid Non-Cartesian Parallel Imaging Reconstruction on Commodity Graphics Hardware Thomas Sangild Sørensen1, David Atkinson1, Redha Boubertakh, 12, Tobias Schaeffter2, Michael Schacht Hansen3 1University College London, London, UK; 2King's College London, London, UK; 3University College London, UK

This presentation describes an implementation of non-Cartesian SENSE and kt-SENSE accelerated on commodity graphics hardware. This inexpensive hardware platform is now fully programmable and very suited for solving reconstruction problems. We show that for both SENSE and kt-SENSE the reconstruction time per frame is now below the acquisition time providing non-Cartesian reconstruction with only minimal delay between acquisition and subsequent display of images. This is demonstrated by four-fold and eight-fold undersampled real-time radial imaging reconstructed in 25 ms to 55 ms per frame.

Poster Sessions

260

1491. Interactive Adjustment of Regularization in SENSE and K-T SENSE Using Commodity Graphics Hardware Michael Schacht Hansen1, David Atkinson1, Thomas Sangild Sorensen1 1University College London, London, UK

This project demonstrates that modern commodity graphics cards (GPUs) can be used to perform fast Cartesian SENSE and k-t SENSE reconstruction. Specifically, the SENSE inversion is accelerated by up to two orders of magnitude and is no longer the time-limiting step. The achieved reconstruction times are now well below the acquisition times thus enabling real-time, interactive SENSE imaging, even with a large number of receive coils. The fast GPU reconstruction is also beneficial for datasets that are not acquired in real-time. We demonstrate it can be used for interactive adjustment of regularization parameters for k-t SENSE in the same way that one would adjust window and level settings. This enables a new way of performing imaging reconstruction, where the user chooses the setting of tuneable reconstruction parameters, in real-time, depending on the context in which the images are interpreted.

1492. Real-Time High-Throughput Scalable MRI Reconstruction Via Cluster Computing Eric Allen Borisch1, Roger C. Grimm1, Phillip J. Rossman1, Clifton R. Haider1, Stephen J. Riederer1 1Mayo Clinic, Rochester, Minnesota, USA

Real-time 3D MR reconstruction, enabled through parallel imaging techniques such as SENSE and GRAPPA, places significant communication and computational challenges on a reconstruction system. We have designed and implemented a distributed, scalable cluster-based image reconstruction system that has enabled real-time 3D reconstruction and visualization during data acquisition. The hardware and software techniques used will be described, as well as reconstruction performance and benchmarks.

1493. Fast MR Image Reconstruction Using Graphics Processing Units Justin P. Haldar1, Sam S. Stone1, Haoran Yi1, Stephanie C. Tsao1, Bradley P. Sutton1, Wen-mei W. Hwu1, Zhi-Pei Liang1 1University of Illinois at Urbana-Champaign, Urbana, Illinois, USA

Advanced algorithms for image reconstruction are becoming increasingly common, but their utility is limited by computational requirements. In this work, we show that significant improvements in reconstruction speed can be achieved by performing data-parallel computations on graphics processing units (GPUs). Specifically, we leverage the resources of a single NVIDIA GeForce 8800 GTX to achieve computational performance of more than 150 GFLOPS, hundreds of times faster than what is reported on a single modern central processing unit (CPU).

1494. Optimized Post-Processing of 7Tesla Simultaneous Triple Contrast: T1-Weighted, TOF Arteriography, and BOLD Venography Peter A. Wassenaar1, Joseph Dunbar1, Donald William Chakeres1, Darlene Meeks1, Michael V. Knopp1, Petra Schmalbrock1 1Ohio State University, Columbus, USA

Inversion Recovery dual turbo gradient echo (IR-dTFE) imaging at ultrahigh field strength can generate images with three types of contrast simultaneously. These are T1 weighting and TOF- arteriography on the first echo and BOLD venography on the second echo. For the MRA information to be useful it is necessary to reconstruct MIP images depicting the vasculature in three dimensions. However, while arteries and veins are well depicted on the original images, standard MIP fails because of increased skull and parenchymal signal. We present here a method for processing 7T IR-dTFE images allowing for MIP visualization of arteries and veins.

1495. Slight Modification of Reconstruction Improves the Isotropy of Non-CPMG Patrick Le Roux1 1GEHC, Palaiseau, France

The non-CPMG sequence permits to acquire phased object in Spin Echo mode without relying on the Carr-Purcell-Meiboom-Gill constrain. But it still suffers from some magnitude modulation when the initial phase of the magnetization varies. It is shown that a slight modification of the reconstruction process, projection direction or change of the reference axis, permits to reduce this anisotropy effect to less than 1%.

1496. Dynamic Imaging Methods Assessed with a 2D MTF Approach Bruno Madore1 1Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA

As the field of dynamic imaging is expanding and new methods are introduced, reliable methodologies to assess the performance of these methods would be highly desirable. We propose here a 2D Modulation Transfer Function (MTF) approach, whereby the performance of a given method gets tested at every combination of spatial and temporal frequencies. As an example, the performance of two dynamic imaging methods, kt-SENSE and UNFOLD-SENSE, was tested.

1497. SETS: Simultaneous Equations with Taylor Expansions in Undersampled Cartesian Data Jason Kraig Mendes1, Dennis L. Parker1 1University of Utah, Salt Lake City, USA

Imaging time constraints often prevent the acquisition of a full k-t space for dynamic objects. In many instances, only part of the k-t space is acquired and the missing information can be approximated using various techniques. UNFOLD is a method which assumes that more than one spatial point can share the same temporal bandwidth without overlap. This work presents a method based on the theory of UNFOLD that allows some degree of overlap in the temporal bandwidth. This can be accomplished with a Taylor series approximation of the signal intensities from each spatial point in the image.

Poster Sessions

261

1498. 3D Reproducing Kernel Hilbert Spaces for Reconstruction of Heart Rate Modulated Cardio-Respiratory Magnetic Resonance Imaging Nicolae Cîndea1, 2, Freddy Odille1, 2, Gilles Bosser3, 4, Jacques Felblinger2, 3, Pierre-André Vuissoz1, 2 1Nancy University, Nancy, France; 2Inserm, Nancy, France; 3Centre Hospitalier Universitaire, Nancy, France; 4Institut Régional de Réadaptation, Nancy, France

Heart MRI reconstructions in free-breathing acquisition is a challenge. Usual techniques assume identical rescaled copies of heart cycle independently of RR length. In this work, a method for cardio-respiratory acquisition and reconstruction in free-breathing taking RR into account is presented. This method uses a Reproducing Kernel Hilbert Space (RKHS) interpolation scheme for retrospective gated reconstruction in 3 dimensions (cardio-respiratory phase and instantaneous heart rate). With this scheme, it is possible to study the cardio-respiratory interactions and particularly respiratory modulation of heart rate and diastolic filling. Clinical cardiac images were reconstructed at a fixed cardio-respiratory phase for two different RR values.

1499. An Automatic Stopping Criterion for Iterative MRI Reconstructions Martin Uecker1, Kai Tobias Block1, Jens Frahm1 1Biomedizinische NMR Forschungs GmbH am MPI für biophysikalische Chemie, Goettingen, Germany

Image reconstructions from undersampled data such as in parallel imaging require the inversion of an ill-posed linear (or non-linear) system. In these cases the quality of the reconstruction critically depends on the choice of the regularization which requires a trade-off between substantial noise and still visible undersampling artefacts. Here, we propose an automatic stopping criterion which terminates the iteration as soon as all undersampling artefacts are fully removed. This is accomplished when the energy density of the inferred k-space positions equals the energy density of the directly measured positions. In an image without undersampling artefacts both quantities should be equal.

1500. Variable Spatial Resolution Reconstruction from Data Acquired with Non-Constant Sampling Density in Phase-Encoding Direction Volker Rasche1, Axel Bornstedt1, Vinzenz Hombach1 1University of Ulm, Ulm, Germany

The variable gridding kernel extent technique is applied for the reconstruction of data acquired on a Cartesian sampling pattern with gradually decreasing dasmpling density in phase encoding (PE) dierection. Examples of carotid artery images show a possible reduction of imaging time of about 70% under the compromise of grdually decreasing spatial resolution along PE direction.

1501. Tradeoff Analysis of Variable Density Spiral K-Space Trajectories Used in MRI Dimitris Mitsouras1, Onur Afacan2, Dana H. Brooks2, Frank J. Rybicki1 1Harvard Medical School & Brigham And Women's Hospital, Boston, Massachusetts, USA; 2Northeastern University, Boston, Massachusetts, USA

Variable density k-space trajectories, such as spirals, have been recently used in many applications to enhance acquisition speed. In such schemes k-space sampling density is reduced below the Nyquist rate, typically as a function of distance from the k-space center. While their use and diversity is rapidly increasing, a systematic comparison and characterization of their tradeoffs has not been performed to-date. Moreover, various reconstruction methods have been proposed for such trajectories. This work provides such an analysis of different variable density trajectories and different reconstruction methods using well-founded metrics such as SNR, root-mean-square error, and point-spread function analysis.

1502. Fast and Accurate Implementation of Radial K-T FOCUSS for Dynamic MRI Using Implicit Gridding Jaeheung Yoo1, Jong Chul Ye1 1KAIST, Daejeon, Republic of Korea

For dynamic MR imaging , radial trajectory is often employed since it is more robust to motion artifacts due to the over-sampled k-space center region. Furthermore, scan time can be further reduced using view undersampling. However, this view undersampling often causes visually annoying streaking artifacts. In radial k-t FOCUSS [1], high spatio-temporal cine imaging without streaking artifact were successfully obtained from undersampled radial trajectory using FOCUSS(FOCal Underdetermined System Solver) [2] that exploits the sparsity of fact x-f support of cardiac cine. We further showed that radial k-t BLAST/SENSE is an approximation of our radial k-t FOCUSS that is asymptotically optimal from compressed sensing perspective. However, the radial k-t FOCUSS was computationally expensive due to the iterative application of the projection and backprojection steps. Application of gridding algorithm to reduce the computational complexity was, however, not often successful due to the propagation of gridding artifacts during FOCUSS iteration. The main contribution of this paper is to eliminate the necessity of gridding or backprojection/reprojection steps by showing that the non-regular sampling structure can be easily incorporated as a filtering process during k-t FOCUSS iteration in regular grid. This implicit gridding operation incurs only minimial computational overhead. Experimental results demonstrate that the modified radial k-t FOCUSS significantly improves the radial k-t FOCUSS algorithm both in reconstruction speed as well as image quality.

1503. A Very Fast Reconstruction Algorithm for Non-Cartesian Multi-Coil Dynamic MRI Uygar Sümbül1, Juan Manuel Santos1, John Mark Pauly1 1Stanford University, Stanford, California , USA

A very fast reconstruction algorithm is presented for non-Cartesian parallel dynamic MRI. The algorithm constrains the images both spatially(via the coil sensitivities) and temporally(via estimating how rapidly individual pixel values change) to achieve alias-free reconstructions. The only major computations are 2 gridding and 2 Fourier operations per each frame. Dynamic whole heart imaging experiments show high temporal resolution of rapidly moving cardiac structures.

Poster Sessions

262

1504. Image Enhancement Via Sliding Window Method for Thermal Noise Reduction Christine S. Law1, Chunlei Liu1, Gary H. Glover1 1Stanford University, Stanford, California , USA

We propose a sliding window self-calibrated parallel imaging method that reduces thermal noise and provides SNR gain over conventional SENSE reconstruction. This method calculates sensitivity profiles dynamically by using a sliding window approach: combining fully sampled data of adjacent frames in an interleaved acquisition, i.e., sensitivity profiles are updated synchronously with image acquisition. No spatial smoothing is performed so as to retain thermal noise in sensitivity profiles. This sliding window technique is especially applicable to acquisition of high spatial-resolution images where thermal noise predominates.

Image Registration Hall D Tuesday 13:30-15:30

1505. GPU-Accelerated Linear and Deformable 3D Medical Image Registration Daniel Henrik Adler1, 2, Sonny Chan, 23, Eric Scott Penner1, 2, J Ross Mitchell1, 2 1University of Calgary, Calgary, Canada; 2Foothills Med Ctr, Calgary Health Region, Calgary, Canada; 3Stanford University, Palo Alto, USA

We describe an automatic medical image registration framework for which all computationally and memory intensive components are implemented on graphics hardware. We accelerate linear and deformable registration 10 to 20-fold on commodity workstations. Accuracy and speed evaluations are performed on neurological clinical data and against other software packages.

1506. Eliminating Functional Localizers Using a Probabilistic Atlas of V1 Oliver Hinds1, Jonathan Polimeni, Mukund Balasubramanian, Graham Wiggins, Florian M. Meise2, Eric L. Schwartz, Bruce Fischl, Lawrence L. Wald, Christina Triantafyllou1 1MIT, Cambridge, Massachusetts, USA; 2Section of Medical Physics, Department of Diagnostic and Interventional Radiology, Mainz University, Germany

Functional localizers simplify the analysis and interpretation of fMRIdata, but cost substantial scantime that could be devoted toinvestigation of other brain function. Here we demonstrate anautomatic method for predicting the boundary of the human primaryvisual cortex (V1) directly from structural scans using aprobabilistic atlas, thus eliminating the need for a V1 localizer. TheV1 boundary was estimated using both fMRI-based localizers and aprobabilistic atlas in six subjects. We found an average distance of less than 7 mm (~2 functional voxels) between theatlas-predicted boundary and the fMRI boundary across subjects.

1507. Development and Application of a Quantitative Water Content Brain Atlas Veronika Ermer1, Heiko Neeb1, Nadim Jon Shah1, 2 1Research Centre Juelich, Juelich, Germany; 2Institute of Physics, Dortmund, Germany

A series of spoiled gradient echo images with different T2*-weighting (QUTE) was acquired in order to create high-resolution quantitative water maps of the human brain. The resulting maps of several volunteers were transformed to the same stereotactic space and were averaged. A first comparison of the new water content atlas of the human brain with the brain of an MS patient is shown.

1508. Non-Rigid Registration of Histological and MRI Sections for Prostate Cancer Mapping Jonathan C. Chappelow1, Anant Madabhushi1, John Tomaszewski2, Michael Feldman2, Mark Rosen2 1Rutgers University, Piscataway, New Jersey, USA; 2University of Pennsylvania, USA

Multimodal image registration methods are also under active development for a variety of visualization and diagnostic applications such as image guided surgery and multimodal image fusion for cancer diagnosis and treatment planning. We present a new non-rigid registration method termed COFEMI-TPS for robust alignment of multimodal images, and demonstrate the method for alignment of 26 prostate MRI-histology slice pairs by identifying spatial extent of cancer on MRI by directly mapping histological cancer ground truth to the resulting co-registered MRI. It was observed that the cancer labels on MRI found using our registration method are qualitatively accurate and comparable to expert-determined labels.

1509. Registration of In-Vivo MRI to Histology Using 3D Block Face Imaging as Common Reference: Application to Cell Tracking in a Murine Model of HIV-1 Encephalitis Mariano G. Uberti1, 2, Yutong Liu1, Huanyu Dou1, Howard E. Gendelman1, Michael Douglas Boska1 1University of Nebraska Medical Center, Omaha, Nebraska, USA

A methodology for registration of in-vivo MRI to histology using 3D block face histology is presented. Superparamagnetic iron oxide (SPIO) labeled bone-marrow derived macrophages (BMM) were injected intravenously and tracked across the blood-brain barrier (BBB) using T2*-weighted MRI. Histological sections (HS) were obtained and stained with Prussian blue. MRI volumes were registered to HS using the introduced methodology. SPIO-labeled cells were detected by subtraction of Pre MRI minus 7 day Post MRI and compared to stained histology. We found that spatial distribution and cell areas detected with in vivo MRI show a good correlation with histopatology. We conclude that MRI can be used in vivo to track cells migrating across the blood-brain barrier in a mouse model of HIV-1 encephalitis. However, further study is required to determine sensitivity and specificity of the method.

1510. Novel Contour-Based Registration Algorithm for VBM Pre-Processing Joao M. S. Pereira1, Peter J. Nestor1, Guy B. Williams1 1University of Cambridge, Cambridge, UK

A novel contour based registration algorithm is proposed which uses as input registered grey and white matter segments output by SPM5. The main goal is to improve surface (ventricles and cortex) normalization, which is known to be sub-optimal in SPM. A two-step method is described for each slice: first, subject and target contours are matched and registered by translations using an approximation to elastic registration; then, demon-based forces are used to drive a viscous-fluid registration around the contours. An increased subject/target similarity was achieved for both controls and Alzheimer’s disease patients.

Poster Sessions

263

Image Analysis - Parameter Mapping Hall D Wednesday 13:30-15:30

1511. Abnormal Iron Content and Distribution in the Basal Ganglia in Parkinson’s Disease: A Susceptibility-Weighted Imaging Study Andreas Ebel1, 2, Lara Stables3, Gail A. Kang4, Graham Glass, 34, Rachel Millin1, 2, Daniel McCoy1, 3, Peter Lorenzen1, 3, Yu Zhang1, 3, Wang Zhan1, 3, Michael W. Weiner1, 3, William Marks, 34, Norbert Schuff1, 3 1Center for Imaging of Neurodegenerative Diseases, San Francisco, California , USA; 2Northern California Institute for Research and Education, San Francisco, California , USA; 3University of California, San Francisco, California , USA; 4VA Medical Center, San Francisco, California , USA

Susceptibility-weighted imaging (SWI) was used to assess abnormalities in the nigrostriatal system in Parkinson’s disease (PD). Abnormal SWI phase values, consistent with increased iron content in brain tissue, were observed in the caudate nucleus, putamen, and the subthalamic nucleus. Furthermore, the regional dispersion of SWI phase, measured in terms of entropy, strongly correlated with PD severity. Taken together, these results imply that SWI has potential for diagnosing PD, assessing disease severity, and tracking response to disease modifying interventions.

1512. Phase-Based Quantification of Magnetic Susceptibility in Healthy Volunteers and Patients with Neurological Disorders at 7T Kathryn E. Hammond1, Janine M. Lupo, Suchandrima Banerjee, Doug A. Kelley, Dan B. Vigneron, 1, Susan M. Chang, Pratik Mukherjee, Sarah J. Nelson, 1 1University of California San Francisco (UCSF) / Berkeley Joint Graduate Group in Bioengineering, San Francisco, California , USA

This study presents a technique for quantifying magnetic susceptibilities χ by post-processing the phase of gradient echo images acquired at 7T at a spatial resolution of 0.35x0.35x1mm. The χ of hemorrhages and calcifications was calculated by comparing phase images of the B0 field to theoretical models of χ effects. Model χ−effects were also used to automatically separate hemorrhage from veins. Detection and characterization of χ−shifted compounds is clinically relevant as a surrogate for brain injury following trauma or secondary to therapeutic radiation and may have an enormous impact on studies of iron deposition in neurodegenerative disorders.

1513. High Resolution Positive Contrast Via Post-Processing from Conventional 3D Imaging Hannes Dahnke1, Wei Liu2, Richard Bowtell3, Joseph A. Frank4 1Philips Research Europe, Hamburg, Germany; 2Philips Research North America, Briarcliff, USA; 3University of Nottingham, Nottingham, UK; 4National Institutes of Health, Bethesda, USA

We demonstrate a method to calculate positive contrast from a conventional gradient echo image, without loss in resolution. The method combines the high resolution, up to now only achieved by means of dedicated positive contrast sequences, with the advantages of a post-processing method that requires no extra measurement time and less a-priori knowledge about the induced susceptibility. We show that it allows for the selective imaging of SPIO labeled cells at higher CNR than in the original image. First 7T data demonstrate the selective imaging of blood vessels by means of this method.

1514. Estimation of Sparse Magnetic Susceptibility Distributions from MRI Using Non-Linear Regularization Bryan Kressler1, 2, Ludovic de Rochefort2, Pascal Spincemaille2, Tian Liu1, 2, Yi Wang1, 2 1Cornell University, Ithaca, USA; 2Weill-Cornell Medical College, New York, USA

Non-linear regularization techniques are used to estimate sparse magnetic susceptibility distributions from MRI field maps. Use of regularization terms that promote sparsity of susceptibilities or sparsity of boundaries between regions of different susceptibilities leads to reduced streaking artifacts, improved boundary delineation, and more accurate estimation of susceptibilities than conventional Tikhonov regularization. The techniques are demonstrated on gadolinium phantoms and agar gels containing superparamagnetic iron oxide particles, and yield estimates of the susceptibility of every voxel in the image.

1515. Estimation of Field Maps with Susceptibility Gradient Mapping Sunbok Lee1, Qun Zhao1 1University of Georgia, Athens, Georgia, USA

In this study a new method based on the Susceptibility Gradient Mapping (SGM) is proposed for estimating a field map without a phase unwrapping procedure. The shift theorem of Fourier Transform shows that the SGM map and field map are equivalent with a proportional constant. Compared with traditional methods of acquiring a field map that needs two phase maps at two different TEs and requires a reliable phase unwrapping algorithm, only one phase map acquired with a single TE is required by the SGM method to generate a field map.

1516. Visceral Fat Assessment with 3D Dual Echo Dixon Technique Kajoli Banerjee Krishnan1, Rakesh Mullick1, Uday Patil1, Ajay Narayanan1, Anthony T. Vu2, Patrice Hervo3 1GE Global Research, Bangalore, India; 2GE Healthcare, Wisconsin, USA; 3GE Healthcare, Buc, France

We have devised an acquisition-based threshold to automatically assess visceral fat fraction from fat-only MEDAL images. The threshold works on a slice-by-slice basis and has been applied to seven clinical datasets representing varying age, gender and body weight. The results are compared with manually drawn visceral masks on water-only MEDAL images that are used to demarcate the subcutaneous layer from the visceral region on the fat-only image. The automatic algorithm provides a systematic estimate of visceral fat within a fraction of 0.1 of the manually assisted method comparable to the range of values reported in the literature.

Poster Sessions

264

1517. Estimation of Water/fat Images, B0 Field Map and T2* Map Using VARPRO Diego Hernando1, Peter Kellman2, Justin Haldar1, Zhi-Pei Liang1 1University of Illinois at Urbana-Champaign, Urbana, Illinois, USA; 2National Institutes of Health, Bethesda, Maryland, USA

T2* estimation in Dixon imaging is important for obtaining accurate water/fat intensity estimates when the relaxation effect cannot be neglected. Moreover, the T2* map can have diagnostic value of its own. Here we present a method for estimating B0- and T2*-maps along with water/fat images from Dixon acquisitions, by extending a recently proposed variable projection method. This method provides accurate estimates regardless of the nonconvexity of the corresponding estimation problem. Furthermore, an efficient approximate algorithm is derived based on Cramer-Rao bound analysis. The performance of the proposed methods has been validated using cardiac imaging data.

1518. Fully-Automated Abdominal Fat Quantification on Water-Saturated MRI Anqi Zhou1, Yao Ding2, Roderick W. McColl2, Paul T. Weatherall2, Qi Peng1 1UT Health Science Center at San Antonio, San Antonio, Texas, USA; 2UT Southwestern Medical Center at Dallas, Dallas, Texas, USA

A fully automated abdominal fat quantification method on water-saturated MR images is presented here. This method combines automatic SAT and VAT segmentation with an automated gray-scale thresholding method for fat voxel determination. 64 slices MR images obtained from 8 subjects were tested using this fully-automated method. A slower semi-automated approach was also used as a reference technique. SAT and VAT quantified using the automated method were slightly smaller (4.4% and 2.7%, respectively) than those obtained by the reference method. About 95% of the slices were quantified with excellent accuracy. We conclude that fully-automated abdominal fat quantification is feasible.

1519. Intensity Inhomogeneity Correction in Two Point Dixon Imaging Olof Dahlqvist Leinhard1, 2, Andreas Johansson1, Joakim Rydell1, 2, Magnus Borga1, 2, Peter Lundberg1, 2 1Linköping University, Linköping, Sweden; 2Center for Medical Image Science and Visualization (CMIV), Linköping, Sweden

A simple and effective approach for correcting intensity inhomogeneity in fat volumes reconstructed from a two point Dixon protocol is to identify pure adipose tissue values and interpolate a correction field with normalized convolution from these. An implementation has been made and tested on 50 acquisitions from 20 different subjects showing high stability.

1520. Phase-Correction Algorithms for Fat-Water Separation with Dual-Echo Sequences Maria A. Schmidt1 1St George's Hospital NHS Trust, London, UK

Dual-echo sequences for two-point fat-water separation often result in images characterised by phase changes along the readout direction due to asymmetric echoes and eddy currents. This work compares phase-correction algorithms in test objects and volunteers, using dual-echo sequences. Pre-processing to remove linear phase drifts and different quality maps to guide the region-growing process were investigated. Algorithms starting from low resolution images and stepping up towards the original resolution were found to provide the best performance. Phase shifts up to 4.1º/pixel were found, and for the largest shifts a linear correction of the phase map was required for correct fat-water separation.

1521. Three Dimensional Phase Sensitive Reconstruction for Water/fat Separation in MR Imaging Using Inverse Gradient Joakim Rydell1, 2, Andreas Johansson1, Olof Dahlqvist Leinhard1, 2, Hans Knutsson1, 2, Gunnar Farnebäck1, Peter Lundberg1, 2, Magnus Borga1, 2 1Linköping University, Linköping, Sweden; 2Center for Medical Image Science and Visualization (CMIV), Linköping, Sweden

Three dimensional phase sensitive reconstruction on two point Dixon volumes has been implemented with use of the inverse gradient. The results has been compared with the inverse gradient method in two dimensions as well as with the well established region growing method proposed by Ma. The inverse gradient method in 3D is able to unwrap the phase field in uncertain regions where the region growing method and the inverse gradient method in 2D come to a stop.

1522. R2* Measurement Errors at Ultrahigh Field in the Presence of Nonlinear B0 Inhomogeneities

Xiangyu Yang1, Petra Schmalbrock1, Steffen Sammet1, Michael V. Knopp1 1The Ohio State University, Columbus, Ohio, USA

Accurate measurement of R2* was hindered by B0-inhomogeneity-induced errors in 2D MRI. While such inhomogeneities can be neglected or corrected as a

linear gradient at low field, nonlinearity must be taken into consideration at ultrahigh field. In this study, we demonstrated that all three commonly-used relaxation models (exponential, exponential-plus-constant, and sinc-modulated exponential) generate severe biases in R2

* estimation in the presence of quadratic B0 inhomogeneity. Phantom study results suggest that such biases can be largely compensated by a quadratic correction using measured B0 map, even when the actual B0 inhomogeneity is not strictly quadratic.

1523. Comparison of ASSETx1 and Corrected Power Images for T2 Quantification Andrew James Patterson1, Martin John Graves1, Tjun Tang1, Jonathan H. Gillard1 1University of Cambridge and Addenbrooke's Hospital, Cambridge, UK

The accuracy of T2 quantification is limited by the decay of the signal into the background noise. In low SNR conditions an optimal multi-coil B1 reconstruction method decreases the mean background noise in comparison to the standard root-sum-of-squares (RSS) reconstruction. We compared the RSS and optimal reconstruction method with a previously published power corrected algorithm. Quantitative T2 measurements obtained in a phantom demonstrated that the optimal reconstruction and the power method are both effective and comparable at improving accuracy and precision.

Poster Sessions

265

1524. Quantification of Whole Brain T1 and T2 Relaxation Times - Automated Grouping of Similar Regions to Define Cortical Areas Berengere M. Aubert-Broche1, Christophe Grova1, Bruce G. Pike1, Louis D. Collins1 1MNI, Montreal, Canada

The aims of the present study were to use rapid volumetric relaxometry methods to (1) quantify T1 and T2 values in specific cortical grey matter (GM) regions for healthy volunteers at 1.5T and (2) aggregate regions showing statistically dependent relaxation times to define cortical areas. To study the spatial statistical dependencies seen in cortical GM relaxation times, the method combines standardized anatomic segmentation, correspondence analysis and ascending hierarchical clustering. Groups of structures that are related statistically are identified and correspond to large cortical regions that have been previously defined anatomically.

1525. Determining Uncertainty in Estimates of Relaxation Time (T2) and Proton Density (S0) Derived from T2 –weighted MRI Using Bootstrap Method Ruiwang Huang1 1Research Center Juelich, Juelich, Germany

T2–weighted spin echo MRI permits determination of the transverse relaxation time (T2) and proton density (S0) within image voxels. Several MR sequences for T2 mapping have been proposed, but little effort has been made to estimate the uncertainty of T2–map. Here, we use the bootstrap approach to investigate uncertainties of (S0, T2) from real T2-weighted MR human brain images and to examine the influence of voxel size on the reliability of (S0, T2) derived from fitting a mono–exponential function.

1526. Polar Decomposition Radio-Frequency Current Density Imaging with Dual-Unwrapping: Simulation and Experimental Results Weijing Ma1, 2, Dinghui Wang1, Tim P. DeMonte2, Adrian I. Nachman1, Michael L. G Joy1 1University of Toronto, Toronto, Canada; 2Field Metrica Inc., Toronto, Canada

Polar Decomposition Radio-frequency Current Density Imaging (PD-RFCDI) is an imaging technique that non-invasively measures current density components inside a sample using a MRI imager. However, due to the requirement of PD-RFCDI to avoid phase wraps, this method was noisier than the rotary echo method and was not implemented on clinical MRI scanners. This work proposes a novel dual-unwrapping technique that removes these constraints on PD-RFCDI. Both the simulation and experiment were used to verify this algorithm.

1527. Experimental Testing of Radio Frequency Current Density Imaging with a Single 180-Degree Rotation Dinghui Wang1, 2, Weiing Ma1, Tim P. DeMonte2, Adrian I. Nachman1, Michael L. G Joy1 1University of Toronto, Toronto, Canada; 2Field Merica Inc., Toronto, Canada

Previously implemented radio frequency current density imaging (RF-CDI) techniques can evaluate the component of the injected Larmor frequency current density in the direction of the static magnetic field only under strict assumption which can be easily violated in biomedical applications. The goal of this work is to experimentally verify a new reconstruction method based on one 180-degree rotation. The results show that with this method one component of the current density can be fully recovered by the two sample orientations.

1528. A Robust Method for Estimation of Regional Pulmonary Parameters in the Presence of Noise Richard A. Guyer1, Michael D. Hellman2, Kiarash Emami1, Stephen Kadlecek1, Robert V. Cadman1, Jiangsheng Yu1, Vahid Vadhat1, Masaru Ishii1, 3, John MacDuffie Woodburn1, Hans Hyonchang Kim1, Rahim R. Rizi1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA; 2Jefferson Medical College of Thomas Jefferson University, Philadelphia, Pennsylvania, USA; 3Johns Hopkins University, Baltimore, Maryland, USA

Principal component analysis (PCA) permits data points in a series of hyperpolarized gas MR images to be clustered based upon their similar signal kinetics rather than their spatial proximity in the images. This allows points to be grouped and averaged to control noise without degrading the resolution of the image. As a result, more reliable estimations of regional lung parameters, such as the alveolar partial pressure of oxygen and the oxygen depletion rate, can be obtained. This is demonstrated with a synthetic dataset derived from images of a rabbit’s lungs.

1529. Noise Statistics, Discretization Artifacts, and SNR Measurements at Very Low Noise Levels Olaf Dietrich1, José G. Raya1, Maximilian F. Reiser1 1Ludwig Maximilian University of Munich, Munich, Germany

The well-known noise distributions of MRI data (Rayleigh, Rician, or non-central chi-distribution) describe the probability density of real-valued (i.e. floating-point) intensity signals; however, MR image data is typically discretized to integers before visualization or archiving in the DICOM format. Depending on the scaling factors used for the discretization and the signal-to-noise ratio (SNR), very low noise levels with substantial discretization artifacts can occur. The purpose of this study was to analyze the consequences of such discretization artifacts and to suggest an improved method for noise and SNR measurements in the presence of very low noise levels.

1530. A Method for Automatic Estimation of Noise Variance and SNR Philip James Beatty1 1GE Healthcare, Menlo Park, California , USA

This work proposes a straightforward method to automatically estimate the noise variance of each receive channel directly from parallel imaging calibration data. The proposed method can be used to identify low SNR channels that do not contribute in a meaningful way to the image reconstruction. By using only data acquired during image acquisition, the need for a separate scan to determine noise variance is eliminated and there is no possibility of incorrect registration between a noise variance acquisition and the image acquisition.

Poster Sessions

266

Tissue Segmentation & Localization Hall D Thursday 13:30-15:30

1531. Analysis of Bilateral Asymmetries in Breast MR Images Based on Texture and Directional Statistics of the Breast Parenchymal Ricardo J. Ferrari1, Anne L. Martel1, 2 1Sunnybrook Health Sciences Centre, Toronto, Canada; 2University of Toronto, Toronto, Canada

The main objective of this work is to use bilateral asymmetry analysis to detect abnormal global changes in the breast parenchymal flow. The analysis, which is based on the differences in texture and directional edge information obtained from the left and right MR breast images, aims to help radiologists in the detection of breast cancer in women with a high risk of developing such disease. Preliminary results of the proposed method has shown an average accuracy of 75.0% on the classification when applied to 40 MRI cases (20 benign and 20 malignant).

1532. Improved Vessel Segmentation Within Tumors Using Implicit Active Contours Driven by Local Binary Fitting Energy Chunming Li1, Zhaohua Ding1, Mary M. Zutter1, John C. Gore2, Thomas Yankeelov3 1Vanderbilt University, USA; 2Institute of Imaging Science, USA; 3Vanderbilt University, Nashville, USA

We apply our recently developed local binary fitting (LBF) method of image segmentation to the problem of separating angiogenic vessels amid a heterogeneous intensity background and show how it yields superior results than common methods of vessel segmentation which include simple intensity thresholding and the Chan-Vese model. The LBF algorithm is less sensitive to noise than thresholding and Chan-Vese model, provides more accurate segmentation and can be applied to images with substantial intensity inhomogeneities.

1533. Fast and Robust Brain-Tissue Segmentation Suyash Prakash Awate1, James C. Gee1 1University of Pennsylvania, Philadelphia, USA

We present a novel, fast, and robust brain-tissue segmentation method.

1534. Pinned Snakes: A Technique to Extract Mouse Brain Data from Whole Head MRI Yutong Liu1, 2, Mariano Uberti1, Michael Boska1 1University of Nebraska Medical Center, Omaha, Nebraska, USA

We developed a technique to extract mouse brain from in vivo head MRI based on an active contour model (“snake”). Most brain extraction techniques developed for human head MRI that employ the image intensity and gradient cannot be directly used for mouse. We include higher level image constraints (“pins”) in the energy function of the snake. The definition of the pins and the initial snakes are automated in this technique. Results have demonstrated that pinned snakes can accurately extract the brain from 3D head MRI with minimal user intervention.

1535. Optimized Filtering of ICA Corrected DCE-MRI Perfusion Images Using Tikhonov Regularization Gernot Reishofer1, Stefan Ropele1, Franz Ebner, Rudolf Stollberger2 1Medical University Graz, Graz, Austria; 2Technical University Graz, Graz, Austria

Previous studies have shown the potential of independent component analysis to separate the signal assigned to macro vessels from tissue signal. This enables an algorithm for minimizing macro-vessel signal in DCE-MRI perfusion imaging to avoid overestimation of relative blood flow and blood volume. The reconstruction step for restoring corrected DCE-MRI time series involves the solution of ill-posed linear systems. Direct back transformation leads to noise amplification in the reconstructed dynamic time series which results in noisy hemodynamic parameter maps. We found that Tikhonov regularization improves the visualization of hemodynamic parameter changes without affecting the quality of macro-vessel minimization through ICA

1536. Kidney Segmentation in 4D DCE-MRI Renal Studies: A Physiological Approach Voreak Suybeng1, Borys Shuter1, David Stringer2, Ashraf Kassim1, Shih-Chang Wang1 1National University of Singapore, Singapore, Singapore; 2National University Hospital, Singapore, Singapore

4D DCE-MRI studies contain temporal information which may be useful in segmenting the kidney, liver and spleen. Three cluster analysis techniques (Kohonen Neural Network, Fuzzy K-Means, Expectation-Maximization) and Factor Analysis of Dynamic Structures (FADS) are compared. All performed similarly in segmenting kidney parenchyma from other abdominal organs. FADS appeared to be most sensitive to the temporal information producing TICs for kidney compartments that were of more physiological interest.

1537. Vein Classification Using Vesselness Filters on SWI Data Acquired at 3T and 7T Peter Jan Koopmans1, Rashindra Manniesing2, Wiro J. Niessen2, Max A. Viergever3, Markus Barth4, 5 1F.C. Donders Centre for Cognitive Neuroimaging, Radboud University, Nijmegen, Netherlands; 2Department of Medical Informatics and Radiology, Rotterdam, Netherlands; 3Image Sciences Institute, University Medical Center Utrecht, Netherlands; 4F.C. Donders Centre for Cognitive Neuroimaging, Radboud University, Nijmegen, Netherlands; 5Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Germany

MR venography data of the brain were acquired at 3T and 7T using susceptibility weighted imaging (SWI). Two automated vein segmentation filters, the Utrecht vesselness filter and Vessel Enhancing Diffusion (VED), were tested. VED results were in excellent agreement with manual segmentation. Results at 3T were marginally better than those at 7T due to increased inhomogeneity at the latter field strength. However, the acquisition time at 3T was 50% longer. SWI at 7T shows good promise for future MR venography.

Poster Sessions

267

1538. Partial Volume Segmentation Using Super-Resolution, Structure Maps and Multi-Scale Processing James P. Withers1, Mark E. Bastin1, Amos J. Storkey1 1University of Edinburgh, Edinburgh, UK

The segmentation of brain MRI volumes is complicated by noise as well as partial volume voxels that contain a mixture of tissue types. Automated algorithms that perform partial volume segmentation often rely on average tissue class maps that may not represent the target anatomy, especially blood vessels and cortical sulci. These small structures can also be smoothed out by aggressive homogeneity constraints or confined to tissue boundaries only. In this abstract, robust techniques for minimizing aliasing through super-resolution, quantifying mixtures over a small number of discrete mixture states, and detecting tube-like structures using differential geometry are examined.

1539. Lesions Detection on 3D Brain MRI Based on Robust Hidden Markov Chain Stephanie Bricq1, 2, Christophe Collet1, Jean-Paul Armspach2 1LSIIT - UMR CNRS 7005, Illkirch, France; 2LINC - UMR CNRS 7191, Strasbourg, France

We present a new automatic robust method to estimate parameters to segment brain MR images (WM, GM, CSF) and MS lesions using the Hidden Markov Chain (HMC) model. For this aim, we use the Trimmed Likelihood Estimator (TLE) to extract outliers and propose to include a priori information brought by a probabilistic atlas. Tests on Brainweb images with MS lesions have been carried out.

1540. Automated Lesion Discrimination and Outlining David Scott Wack1, 2, Michael Dwyer1, Sara Hussein1, Christopher Caiola1, Peter Hojczyk1, Robert Zivadinov1 1State University of New York at Buffalo, Buffalo, USA

A method which uses Stochastic Discrimination for the detection of MS lesions was trained using 40 scans from MS subjects acquired from 4 scanners. Thirty-nine scans were used as a test set. The pattern recognition results were subsequently used in a stage which created an outline of the lesions in a format accepted by JIM (Java Image Manipulation) software, allowing for further editing of the results. A comparison of the un-edited ROIs and expert drawn ROIs had median Kappa value of .61. ROIs from either method predicted over 93% of the lesions found in the other.

1541. Increasing the Sensitivity of Detection of Targeted MRI Contrast Agents Using Bayesian Image Analysis Methods Holly C. Canuto1, 2, Marko Velic3, Charles I. McLachlan3, Mikko I. Kettunen1, 2, Anant S. Krishnan1, Andre' A. Neves1, 2, Maaike M. de Backer1, De-en Hu1, Michael P. Hobson1, 3, Kevin M. Brindle1, 2 1University of Cambridge, Cambridge, UK; 2Cancer Research UK, Cambridge, UK; 3Metropolis Data Consultants, Cambridge, UK

The capability to perform reliable and accurate automated segmentation of MR images does not currently exist within the MR imaging community. Bayesian image analysis methods have been used successfully in the astronomy community for more than thirty years to de-noise images and enhance feature recognition. We have developed a Bayesian Multi-Region Segmenter (BMRS) to provide reliable assessment of contrast heterogeneity within murine lymphomas and potentially enhance the sensitivity of contrast agent detection.

1542. Gradient-Field-Based MRI Knee Cartilage Segmentation Algorithm with Self Correction Ana Rodriguez-Soto1, 2, Julio Carballido-Gamio2, Thomas M. Link2, Sharmila Majumdar2 1Universidad Iberoamericana, Mexico City, Mexico; 2University of California, San Francisco, San Francisco, California , USA

In this work a semi-automatic cartilage segmentation technique is presented. The bone cartilage interface was extracted by Canny edge detection and was used as initialization for the segmentation of the articular surface. First and second order gradients of pixel intensities were used to move the control points of the splines representing the cartilage contours. A self correction technique based on local cartilage thickness values of adjacent slices was implemented to reduce user interaction. The algorithm was tested with 10 human knees with different levels of OA which were segmented twice. The global CV was 0.57% for 3D cartilage thickness and 1.69% for cartilage volume demonstrating the good performance of the technique.

1543. A Novel Pixel-By-Pixel Texture Analysis Technique Improves Frequency Resolution of Local MS Spectra Sylvia Drabycz1, J Ross Mitchell1 1University of Calgary, Calgary, Canada

Previous studies have demonstrated that local spectral analysis using the polar S-transform (PST) can help discriminate between normal-appearing white matter (NAWM) and active as well as inactive multiple sclerosis (MS) lesions on MR images. However, the very large number of computations required for even moderately sized images relegates the PST to a region-of-interest approach, which reduces the resulting spectral resolution. We introduce a novel spectral analysis technique that uses circularly symmetric windows in the frequency domain and averages the contribution of each complex spectral contribution. Our method produces a complex, and fully invertible, 3D local frequency domain with complete spectral resolution.

1544. A Common De-Scalping Procedure for Various Different MRI Proctols Ankur Purwar1, RKS Rathore1, RK Gupta2, MK Sarma1, G Bayu1, D Rathore1, R Trivedi2, JK Singh1, Anup Singh1, S Verma1 1IIT Kanpur, Kanpur, India; 2SGPGIMS Lucknow, Lucknow, India

De-scalping the brain is a very useful procedure with enormous applications in visualization, surface rendering, decreasing the complexity of subsequent processing algorithms, and the like. Many applications related to brain imaging either require, or benefits from the ability to accurately segment brain from the non-brain tissue. For example, (a) in the registration of b0-images to DW images in DT-MRI, both b0 and DW images often contain considerable portions of eyeballs, skin etc. that cause problems in the registration process, which gets improved once these non-brain parts of the images are removed, (b) a second application of de-scalping is in tissue-type segmentation, which helps in isolating brain tissue from other parts of the stack such as CSF, (c) in the removal of strong ghosting effects which can occur with EPI and (d) creating probabilistic atlases from large groups of subjects. This work describes an automatic procedure for de-scalping in the brain for MRI for scans with axial orientation. The procedure has effective in all types of brain imaging techniques including T1, T2W, PD, and T2W-EPI.

Poster Sessions

268

1545. Computer-Assisted Segmentation of White Matter Lesions in 3D MR Images, Using Support Vector Machines Zhiqiang Lao1, Dinggang Shen1, Elias R. Melhem1, Nick R. Bryan1, Christos Davatzikos1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA

We present a computer-assisted white matter lesions (WMLs) segmentation method, based on local features extracted from multi-parametric MRI sequences. A Support Vector Machine (SVM) classifier is first trained on expert-defined WML’s, and is then used to classify new scans. Subsequent post-processing analysis further reduces false positives by utilizing anatomical knowledge and measures of distance from the training set. Cross-validation on 35 patients from 3 different imaging sites with WMLs of varying sizes, shapes and locations tests the robustness and accuracy of the proposed segmentation method, compared to the manual segmentation results from two experienced neuroradiologists.

MR Elastography Methodology Hall D Tuesday 13:30-15:30

1546. Comparison of Dynamic MR Elastography of Living Brain at 7 T and 1.5 T Uwe Hamhaber1, Dieter Klatt1, Bernd Beierbach1, Sebastian Papazoglou1, Maurice Hollmann2, Jörg Stadler3, Ingolf Sack1, Johannes Bernarding2, Jürgen Braun1 1Charité - Universitätsmedizin Berlin, Berlin, Germany; 2Otto-von-Guericke University, Magdeburg, Germany; 3Leibniz Institute for Neurobiology, Magdeburg, Germany

MR elastography allows the quantification of viscoelastic parameters of the living brain at 1.5 T and 3 T. The stronger static magnetic field at 7 T imposes imaging complications by RF resonances and stronger susceptibility artifacts and distinctly different relaxation times of brain tissue. The objective of the presented study is to investigate whether the determination of viscoelastic properties of brain tissue is feasible at 7T and if the reconstructed viscoelastic parameters are comparable with those determined at 1.5 T.

1547. MR Elastography Reveals Tissue Degeneration in Multiple Sclerosis Patients Jens Thomas Wuerfel1, 2, Bernd Beierbach1, Dieter Klatt1, Uwe Hamhaber1, Sebastian Papazoglou1, Juergen Braun1, Ingolf Sack1 1Charité - University Medicine Berlin, Berlin, Germany; 2University Schleswig-Holstein, Luebeck, Germany

Physicians have been using palpation as an effective clinical examination tool for centuries. However, the brain, an organ that eluded the examination by the palpating hand, has not thus far been accessible in vivo. Magnetic resonance elastography is a unique, non-invasive approach to evaluate the elasticity of soft tissues in vivo. Here, we present cerebral viscoelasticity data from 40 multiple sclerosis patients with relapsing-remitting disease course, as well as from 17 matched healthy controls. Mean shear stiffness was significantly lower in MS patients, exceeding 0.5kPa in comparison with healthy brains. MRE is feasible for application in a routine clinical setting.

1548. Radiation Force Imaging and HIFU Therapy Monitoring in Phantom Gels by Means of High Resolution MR-Elastography – in Vivo Application to the Rat Brain Benoit Larrat1, Ralph Sinkus1, Mathieu Pernot1, Jean-François Aubry1, Mickael Tanter1, Mathias Fink1 1ESPCI-CNRS-Univ Paris 7-INSERM, Paris, France

In this study, an HIFU experiment together with an MR-Elastography acquisition is performed inside a 7T scanner. The exact position of the ultrasound focal point is visualized by means of a dedicated motion sensitized sequence. This allows checking the correct positioning of the targeted tissue relatively to the ultrasound beam with low power. The elasticity maps are calculated before and after HIFU treatment, showing significant stiffening at the exact location of the focal spot. In vivo preliminary experiments in the rat brain have also been conducted.

1549. In Vivo Myocardial MR Elastography: Observation of Stiffness-Related Shear-Wave Amplitude Variations Thomas Elgeti1, Jens Rump1, Dieter Klatt1, Uwe Hamhaber1, Sebastian Papazoglou1, Jürgen Braun1, Bernd Hamm1, Ingolf Sack1 1Charité Universitätsmedizin Berlin, Berlin, Germany

Wave amplitude variations of external introduced low frequency shear waves are detected with phase-sensitive MR elastography sequences in human myocardium of 6 healthy volunteers.

1550. MRE of the Eye: Inversion Using a Thin Spherical-Shell Model Daniel V. Litwiller1, Sung Lee1, Arunark Kolipaka1, Kevin J. Glaser1, Jose S. Pulido1, Richard L. Ehman1 1Mayo Clinic, Rochester, Minnesota, USA

Assessments of ocular, intraocular and orbital rigidity, are currently limited to qualitative assessment by direct palpation, more invasive methods or other conventional methods such as tonometry, which may yield indirect or inaccurate results. Recently, MR Elastography (MRE) has emerged as a promising technique for investigating motion in the eye and other fluid-filled membranes. Because the eye is not a homogeneous solid, however, reconstructing its shear stiffness with existing wave inversion algorithms is not feasible. In this work, we demonstrate that it is possible to interpret MRE images of flexural waves in the eye using direct inversion in a thin spherical-shell model.

Poster Sessions

269

MRS Methodology Hall D Wednesday 13:30-15:30

1551. The Spurious Echo Artefact in 1H-MRS and PRESS Åsa Carlsson1, 2, Maria Ljungberg1, 2, Göran Starck1, 2, Eva Forssell-Aronsson1, 2 1Göteborg University, Gothenburg, Sweden; 2Sahlgrenska University Hospital, Gothenburg, Sweden

The spurious echo artifact is often encountered in in vivo MRS and is once again actualized with application of MRS in more susceptibility influenced regions. It originates from signals excited in regions outside the VOI that refocus into an echo during signal acquisition. Here k-space formalism was used as a new approach to analyze the spurious echo artifact of the PRESS sequence, and in vitro measurements were performed for verifications and characterisations. Different coherences were separately refocused and studied. The FID of the second refocusing pulse was most probable to cause an artifact and also caused the most pronounced.

1552. Exploiting the Chemical Shift Displacement Effect in the Detection of Glutamate and Glutamine (Glx) with PRESS Atiyah Yahya1, 2, B. Gino Fallone1, 2 1Cross Cancer Institute, Edmonton, Canada; 2University of Alberta, Edmonton, Canada

The observation of the collective levels of glutamate/glutamine (Glx) by proton magnetic resonance spectroscopy is of value in the study of cancer, neurodegenerative and psychiatric disorders. A PRESS sequence is presented in this work that can yield high signal, comparable to that which can be achieved by a one-pulse acquire sequence, from the C2 protons of Glx at long echo times which is favourable for the decay of macromolecule signal. The efficacy of the sequence was verified on phantoms and in vivo on brain.

1553. Multiple-Refocusing for Suppression of Myo-Inositol for Glycine Measure at 1.5T: Simulation Study Changho Choi1 1University of Texas Southwestern Medical Center, Dallas, USA

A preliminary result of a numerical study for suppression of myo-inositol (mI) for detection of the glycine (Gly) singlet at 3.55 ppm for 1.5T is reported. Multiple refocusing was investigated with density-matrix simulation to calculate the responses of the strongly-coupled resonances of mI. The study indicated that suppression of mI enhances with increasing number of 180° pulses, N. It is predicted that, for an mI-to-Gly concentration ratio of 8, ignoring T1 and T2 effects, mI-to-Gly peak amplitude ratio is 39%, 35%, 31%, 12% and 4% at TE = 108, 146, 176, 239, and 298 ms, for N = 3, 4, 5, 6, and 7, respectively.

1554. Glutamate and Glutamine Discrimination Via Constant Echo Time Difference Spectroscopy Jeff Snyder1, Richard B. Thompson1, Alan H. Wilman1 1University of Alberta, Edmonton, Canada

This study investigates the discrimination of glutamate and glutamine using a simple constant echo time subtraction spectroscopy method based on PRESS. The technique relies on coupled spin signal variation differences between glutamate and glutamine along a constant TE line. The theoretical simulations calculated 96% of the glutamate/glutamine signal in the 2.06-2.15 ppm was due to glutamate. Phantom and volunteer measurements were performed to support the simulations and validate the technique. The results illustrate a large signal remaining in the above noted ppm range, with other resonances suppressed.

1555. 13C MRS Study of Human Ornithine Transcarbamylase Deficiency Andrea Lynne Gropman1, Napapon Sailasuta2, Lawrence Robertson3, Kent Harris4, Peter S. Allen5, Brian D. Ross 1Children's National Medical Center, Washington, USA; 2Huntington Medical Research Institutes, Pasadena, California , USA; 3Spin Dynamics, South Pasadena, USA; 4Huntington Medical Research Institutes, Pasadena, USA; 5University of Alberta, Edmonton, Canada

Ornithine transcarbamylase deficiency leads to hyperammonemic encephalopathy. 1H MRS shows elevations in glutamine and decreases in myoinositol and choline. Specificity of 1H MRS suffers from complex peak patterns due to J-coupling. 13C MRS can quantitate distinct signals from Glu and Gln. We imaged three subjects with partial OTCD and compared to controls using natural abundance 13C MRS followed by intravenous low dose 99% 1-13C glucose infusion. 1-13C glucose appeared in the 13C brain spectra; enrichment of C1 – thru C5 glutamate and glutamine occurred. Excess enrichment in glutamine C4 and C2 in subjects was consistent with abnormality in glial glutamine synthesis.

1556. 13C Isotopomer Metabolic Modeling: Automatic Generation of the Mathematical Model Julien Valette1, Alexander Shestov1, Kamil Ugurbil1, Pierre-Gilles Henry1 1CMRR, University of Minnesota, Minneapolis, Minnesota, USA

Because they describe 13C spectra fine structure, 13C isotopomer metabolic models take full advantage of the biochemical information that can be measured by 13C NMR during an infusion of labelled substrate, allowing the measurement of metabolic fluxes with an increased accuracy. In this work, a concept related to isotopomers, dubbed “probabimer”, which allows reducing the number of equations compared to isotopomer models, is briefly introduced. Then a program is presented that automatically generates and simplifies the differential equations describing the time evolution of probabimers. This program is finally exemplified on the neuron-glia model.

1557. Improved Spectral Dispersion in Proton MR Spectroscopy of the Neurochemical Profile in the Rat Brain at 14.1 Tesla Vladimir Mlynárik1, Cristina Cudalbu1, Lijing Xin1, Rolf Gruetter1, 2 1Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; 2Universities of Lausanne and Geneva, Switzerland

Ultra-short-echo time spectra of rat brain were obtained at 14.1 Tesla. Metabolite concentrations were calculated using LCModel and were compared with those obtained at 9.4 T. It was found that quantitation of metabolites, which are poorly characterized in proton MR spectra in vivo (such as alanine, glycerophosphocholine, GABA, glycine and NAAG), was improved.

Poster Sessions

270

1558. Determination of the Glutamate-Glutamine Cycling Flux Using Two-Compartment Dynamic Metabolic Modeling is Sensitive to Astroglial Dilution Jun Shen1, Douglas Rothman, Kevin Behar 1NIMH, Bethesda, Maryland, USA

13C MRS combined with the infusion of [1-13C]glucose has been used to measure the rate of the glutamate-glutamine cycling. Here we evaluated the accuracy and precision of 13C MRS measurement of this cycling rate using Monte Carlo analysis of a previously published two-compartment metabolic model of the glutamate-glutamine cycle which takes into account astroglial dilution. The Monte Carlo analysis confirmed that the neuronal TCA cycle and glutamate-glutamine cycle fluxes can be determined reliably from the 13C enrichment time courses measured with 13C MRS during infusion of [1-13C]glucose.

1559. Time Resolved Functional Proton MR Spectroscopic Investigations of Cortical Glutamate Changes During Painful Heat Stimulation Alexander Gussew1, Reinhard Rzanny1, Hans Christoph Scholle2, Werner Alois Kaiser1, Jürgen Rainer Reichenbach1 1Friedrich-Schiller University of Jena, Jena, Germany; 2Friedrich-Schiller-University of Jena, Jena, Germany

Cortical alternations of glutamate concentrations induced by cyclic peripheral painful heat stimulations at the left forearm were measured by means of time resolved in vivo 1H-fMRS in the left insular cortex of 3 volunteers. Synchronization between the stimulation unit and the MR-scanner allowed acquisition of spectra at two different time points (stimulus and rest) of the stimulation cycle. For all volunteers spectra acquired during the stimulus showed increases of glutamate concentration (up to 17%) compared to the reference spectrum without stimulation. However, observed differences of glutamate concentration during the resting period among the volunteers indicate interindividual variability.

1560. In Vivo 13C Spectroscopy of Human Brain on a Clinical 3T Scanner Using [2-13C]Glucose Infusion Shizhe Steve Li1, Yang Zhang1, Jehoon Yang1, Maria Ferraris Araneta1, Robert B. Innis1, Jun Shen1 1NIH, Bethesda, Maryland, USA

Contaminatiion from subcutaneous lipid signals and strong RF decoupling power requirement are two major technical difficulties in human brain 13C spectroscopy when [1-13C]glucose is used. In a recent study of monkey brain, we proposed a novel strategy of using [2-13C]glucose infusion and detecting 13C label incorporation into the caboxylic/amide spectral region to overcome those difficulties. Here we report results of human brain 13C spectroscopy using [2-13C]glucose infusion on a 3 Tesla clinical scanner. With pseudo noise decoupling, we were able to acquire 13C spectra of carboxylic/amide carbons with reduced average RF power deposition and without lipid contamination.

1561. A Strategy for 13C MRS Study of Human Frontal Lobes Napapon Sailasuta1, Larry Robertson2, Kent Harris1, Brian Ross1 1Huntington Medical Research Institutes, Pasadena, California , USA; 2Spin Dynamics, South Pasadena, California , USA

Evaluation of several low power noise proton decoupled carbon detect MRS method for glutamatergic neurotransmission of the human frontal lobes.

1562. Time-Zero Signal Truncation in CRAZED Experiments Due to Rephasing Gradient Delays Leads to Incorrect Frequency-Domain Lineshapes Stefan Kirsch1, William Edmund Hull1 1German Cancer Research Center (DKFZ), Heidelberg, Germany

In contrast to the decay of a conventional pulse-acquire FID, the time-domain signal from of a CRAZED-type pulse sequence for coherence order n > 1 increases from initially zero to a maximum, followed by an exponential decay. We show that the finite duration of the coherence rephasing gradient and any subsequent recovery delays lead to loss of the initial portion of the time-domain signal. This so-called “time-zero truncation artefact” results in an altered frequency-domain lineshape with incorrect integral and linewidth. Correct analysis requires time-domain fitting of right-shifted data.

1563. In Vivo Human Whole Cerebellum MRS Under Severe Field Inhomogeneity with IDQC Method Tianliang Gu1, 2, Zhong Chen1, Xiaoxu Liu1, Ling-chih Lin1, Jianhui Zhong1 1University of Rochester, Rochester, New York, USA

An intermolecular double quantum coherence (iDQC) 2D MRS pulse sequence was created and implemented on a 3T scanner for acquisition of human brain 1H spectra in regions susceptible to field inhomogeneity such as the cerebellum. High resolution 1D MRS could be obtained in a few minutes with iDQC over the whole cerebellum, whereas conventional single voxel 1D MRS was working successfully only when regions much smaller were covered. NAA/Cr and Cho/Cr measured with both methods in 5 healthy subjects agreed well with each other.

1564. Two-Dimensional Zero-Quantum Coherence 1H NMR Spectroscopy of Glutamate and Glutamine Sarah Rebecca Snyder1, Stefan Kirsch1, Katharina Kraus1, Peter Bachert1 1German Cancer Research Center, Heidelberg, Germany

Strong signal overlap of glutamate and glutamine creates a spectroscopic imaging challenge. To more precisely differentiate the two, we recorded series of ¹H NMR stimulated-echo acquisition mode (STEAM) spectra with varying mixing time intervals from Glu and Gln model solutions on a 3 Tesla whole-body MR tomograph. For scalar-coupled molecules, this leads to an intrinsic phase modulation frequency of zero-quantum coherences (ZQC). The outer peaks of the α -CH triplet of both glutamate and glutamine could be clearly identified due to their chemical shifts and ZQC modulation. This provides an additional parameter for the identification of glutamate and glutamine.

1565. Double Quantum Spectroscopy Using Phase Rotation at 7T Saadallah Ramadan1, Eva M. Ratai2, Lawrence L. Wald2, Graham C. Wiggins2, Carolyn E. Mountford3 1Brigham and Women's Hospital, Boston, Massachusetts, USA; 2Massachusetts General Hospital, Boston, Massachusetts, USA; 3Brigham and Womens Hospital, Boston, Massachusetts, USA

**Add synopsis**

Poster Sessions

271

1566. Sensitivity of Single Shot Multiple J-Coupled Metabolite Detection Using Dual Sel-MQC (D-Sel-MQC) Editing Gerd Melkus1, Philipp Mörchel1, Markus Kotas1, Michael Flentje1, Peter Michael Jakob1 1University of Würzburg, Würzburg, Germany

The spectral editing technique Sel-MQC (Selective Multiple Quantum Coherence) is extended by an additional spectral selective pulse to increase the number of detectable J-coupled resonances in a single scan. The first frequency selective pulse is placed on the 1.1-1.7 ppm region to excite lactate and alanin, the second frequency selective pulse is placed on the 1.8-2.4 ppm region to excite γ−aminobutyric acid, glutamate and glutamine. The timing of the sequence is defined by J of the edited resonances. Double-quantum coherences are filtered using gradients. The sensitivity of the one scan editing sequence is evaluated using simulations and phantom experiments.

1567. Shortening of Metabolite Relaxation Times of Prefrontal Cortex in Mild Cognitive Impairment Antonio Napolitano1, 2, Federico Giove, 23, Gianfranco Spalletta4, Dorothee P. Auer1, Bruno Maraviglia2, 3 1University of Nottingham, Nottingham, UK; 2La Sapienza University, Rome, Italy; 3Enrico Fermi Center, Rome, Italy; 4Santa Lucia Foundation, Rome, Italy

A spectroscopy study was performed to measure the T2 values of NAA, tCrin Alzheimer’s patients and in controls. The amplitudes of NAA, tCr and Cho from 16 spectra with different TE were fitted and the T2 values of control subjects were compared with those of Alzheimer’s patients. We found a 13% decrease in T2 of NAA (p<0.035), a 9% decrease in T2 of tCr (p<0.01) and a 15% decrease in T2 of Cho (p<0.033). Such decreases we found in the metabolite relaxation times can be correlated to the presence of elevated iron levels associated with neurodegenerative disorders such as Alzheimer’s disease.

1568. Bone Marrow 1D and 2D Correlation MR Spectroscopy at 7T Saadallah Ramadan1, Eva M. Ratai2, Lawrence L. Wald2, Graham C. Wiggins2, Carolyn E. Mountford3 1Brigham and Women's Hospital, Boston, Massachusetts, USA; 2Massachusetts General Hospital, Boston, Massachusetts, USA; 3Brigham and Womens Hospital, Boston, Massachusetts, USA

When compared to low field MRS, high field MRS offers additional benefits, including spectral dispersion. However, benefits come with more technological challenges from an RF, Bo and pulse sequence design perspective. An attempt to implement 1D and 2D spectroscopic correlation experiments on a 7T whole body magnet is carried out, with application to tibial bone marrow. The resulting spectra are analyzed and compared to existing spectra at lower fields.

1569. 1D and 2D Correlation Spectroscopy of Muscle at 7T Saadallah Ramadan1, Eva M. Ratai2, Lawrence L. Wald2, Graham C. Wiggins2, Carolyn E. Mountford3 1Brigham and Women's Hospital, Boston, Massachusetts, USA; 2Massachusetts General Hospital, Boston, Massachusetts, USA; 3Brigham and Womens Hospital, Boston, Massachusetts, USA

**Add synopsis**

1570. 1H MRS in the Human Calf with a Spatially Selective RF Surface Coil Maria Alfonsetti1, Claudia Testa2, Stefano Iotti2, Emil Malucelli2, Valeria Clementi2, Bruno Barbiroli2, Giuseppe Placidi1, Antonello Sotgiu1, Marcello Alecci1 1Università di L'Aquila, L'Aquila, Italy; 2Università di Bologna, Bologna, Italy

In this work we describe the use of transverse field RF coils to improve proton MRS SNR and spatial selectivity at 1.5T in the resting calf of a healthy volunteer. The RF coil of diameter 10 cm allows in the calf muscle an improved 1H-PRESS SNR along the A/P direction within a given depth from the surface. These features should be of benefit in clinical MRS studies of muscle metabolism and in brain metabolites quantification.

1571. An Integrated Analysis Platform for Magnetic Resonance Spectroscopy Jordan Hovdebo1, 2, Herve Momo-Jeufack2, Michael West2, Lawrence Ryner1, 2 1National Research Council Institute for Biodiagnostics, Winnipeg, Canada; 2University of Manitoba, Winnipeg, Canada

We present a new system for individual and population analyses of magnetic resonance spectroscopy data. The system consists of two parts: a database for storage, and a client application for accessing the information and performing analyses. Combined, these two parts give an analysis platform capable of managing the large volumes of information generated and sufficiently flexible to accommodate several sources of clinically-relevant data.

1572. On the Importance of Quality Assurance in Spectroscopic Imaging of Prostate Mahir Sinan Ozdemir1, Yves De Deene2, Geert Villeirs2, Eric Achten2, Ignace Lemahieu1 1Gent University, Gent, Belgium; 2Gent University Hospital, Gent, Belgium

Spectroscopic imaging of prostate (SI) aided by endorectal coils (ER) has gained considerable interest recently as it provides high SNR and spatial resolution and allows one to detect signal changes, in particular, of the metabolites such as citrate (Cit) and choline (Cho). Although the diagnostic statements are based on the obtained data and the quality of the data and accuracy of the methods used are important for a correct diagnosis, a routine quality assurance of prostate spectroscopy is lacking. In this contribution, we duplicated a typical clinical prostate SI as performed commonly by using a homogenous phantom to assess the accuracy of ratio-based results.

1573. Benign and Atypical Meningioma Metabolic Differences by HR-MAS Molecular Profiling Daniel Monleon1, Jose Manuel Morales2, Jose Gonzalez, Fernando Talamantes, Concha Lopez-Gines2, Miguel Cerda-Nicolas2, Bernardo Celda2, 3 1Fundacion Investigacion Hospital Clinico Universitario Valencia, Valencia, Spain; 2University of Valencia, Valencia, Spain; 3Centro de Investigación Biomédica en Red de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Spain

Meningiomas are neoplasms that arise from the leptomeningeal covering of the brain and spinal cord, accounting for 15%–20% of CNS tumors. Although the majority of these tumors are histologically benign, some meningiomas show signs of malignancy such as marked vascularity, mitotic figures, nuclear pleomorphism, focal necrosis, or infiltration to the adjacent brain. The WHO classifies meningiomas into three histologic grades: benign, atypical, and anaplastic in accordance with the clinical prognosis. Atypical and anaplastic meningiomas tend to recur. In this communication, we show differences between benign and atypical meningiomas in HRMAS molecular profiles of meningioma biopsies.

Poster Sessions

272

1574. Three-Dimensional Isotropic Filter Design with Arbitrary Pass-Band and Stop-Band Specifications Joonsung Lee1, Elfar Adalsteinsson1 1Massachusetts Institute of Technology, Cambridge, Massachusetts, USA

Variable-density sampling of k-space with accompanying proportional filtering, offers improved spatial impulse response without SNR tradeoffs . Prior work relied on 1-D filter specifications, a widely investigated topic, while the general three-dimensional case is much less studied. While three dimensional filters can be derived by simple transformations from 1D, optimality of the filter will in general be lost. We present here an algorithm for the direct design of an optimal, spherically symmetric, three-dimensional filter with arbitrary extent in k-domain, and pass-band (i.e. voxel size) and stop-band (side lobe suppression) specified in the image domain.

1575. Optimal Phased Array Combination for Spectroscopy Mark Bydder1, Gavin Hamilton1 1University of California San Diego, San Diego, California , USA

A method is described for making a weighted linear combination of the spectra acquired by a phased array coil. Unlike previous combination methods, no reference points in the data are chosen to represent the coil weights. Instead all the data points are used, which results in more reliable estimation.

Spectroscopy Methodology: Miscellaneous Hall D Thursday 13:30-15:30

1576. Reproducibility Study of Whole-Brain Spectroscopic Imaging with Automated Quantification Meng Gu1, Dirk Mayer1, Edith Sullivan, Adolf Pefeeferbaum, Daniel Spielman1 1Stanford University, Stanford, USA

A reproducibility study of proton magnetic resonance spectroscopic imaging of the human brain was conducted to evaluate the reliability of an automated 3D in vivo spectroscopic imaging acquisition and associated quantification algorithm. The complete study consisted of 7 healthy adult subjects scanned within a one month interval to assess inter-subject variability and one subject scanned six times to assess intra-subject variability. The observed inter-subject and intra-subject coefficients-of-variation from five regions-of-interest were comparable to those reported for single-voxel acquisitions from similar ROIs. These results demonstrate that reproducible whole-brain 1H-MRSI data can be robustly obtained with the proposed methods.

1577. Imaging of Physiologic Lactate Concentrations by SelMQC Spectroscopy with Hadamard Slice Selection on a Clinical Scanner Eric Albert Mellon1, Stephen J. Pickup1, Gamliel Isaac1, Sueng Cheol Lee1, Edward J. Delikatny1, Ravinder Reddy1, Jerry D. Glickson1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA

Selective Homonuclear Multiple-Quantum Coherence-transfer (Sel-MQC) lactate spectroscopy has shown excellent promise for the detection of lactate with full fat and water suppression. While 2D versions of this technique have been published on animal scanners and very recently a 3D technique has been proposed, to our knowledge these techniques have not been implemented on a clinical scanner. Here a 2D phase encoded, 1D Hadamard encoded Sel-MQC sequence is demonstrated in single and double quantum modes for the detection of physiologic levels of lactate in phantoms on a 3T clinical scanner with a standard coil for the goal of future clinical studies.

1578. New Technique for Simultaneous Acquisition of Metabolite and Water Signals in 1H-CSI Toru Shirai1, Yukari Yamamoto1, Yoshitaka Bito1, Satoshi Hirata2 1Hitachi, Ltd., Kokubunji-shi, Japan; 2Hitachi Medical Corporation, Kashiwa-shi, Japan

We propose a new technique for simultaneous acquisition of metabolite and water signals in CSI. The pulse sequence of this technique includes a CHESS pulse whose amplitude is switched alternately in accordance with phase encoding steps in order to reverse the polarity of the water signal. Because the water signal is shifted to the top and bottom of the reconstructed image, the metabolite signal is separable from the water signal. The results of phantom experiments showed that this technique was effective in suppressing water signal, which suggests the usefulness of the proposed method.

1579. Lipid Suppression with Variable-Density Spiral Trajectory for Volumetric Brain CSI Joonsung Lee1, Borjan Gagoski1, Elfar Adalsteinsson1 1Massachusetts Institute of Technology, Cambridge, Massachusetts, USA

Estimates of cortical brain metabolites using chemical shift imaging (CSI), especially those of NAA, are severely hampered by strong, subcutaneous lipid signals. by reducing the spatial side lobes and using the variable-density spiral trajectories, lipid signals can be bound spatially to reduce the amount of lipid signal leakage. A 3D filter was designed and demonstrated in variable-density spiral-based trajectory for volumetric brain CSI. Excellent lipid suppression was achieved via the filter function without minimal SNR tradeoffs.

1580. Improved Spatial Coverage for 3D MRSI by Automatic Placement of Outer-Volume Suppression Saturation Bands Eugene Ozhinsky1, 2, Sarah J. Nelson1, Daniel B. Vigneron1 1University of California San Francisco, San Francisco, California , USA

To improve coverage of the brain, while simultaneously reducing lipid contamination, we have developed a technique for automatic optimization of sat band position and orientation that simultaneously maximizes coverage of subcutaneous fat and minimizes the portion of brain tissue that is removed. This allows to prescribe a much larger PRESS box and provides MR spectra from a significantly larger volume of the brain.

Poster Sessions

273

1581. Off-Resonance Effects in Non-Conventional Spectroscopic Imaging Claudiu Schirda1, Fernando Boada2 1State University of New York at Buffalo , Buffalo, New York, USA; 2University of Pittsburgh, Pittsburgh, Pennsylvania, USA

Fast spectroscopic imaging enables resolving the spectral information at much higher spatial resolutions compared to classical Chemical Shift Imaging (CSI) experiments, in shorter scan times. Besides fast CSI techniques that sample k-space on a Cartesian grid (e.g. Dixon), a number of non-conventional approaches employing non-Cartesian trajectories have been developed. Among them are stochastic trajectories, PREP, spiral and rosette trajectories. We theoretically analyze and experimentally demonstrate the off-resonance effects associated with these non-conventional encoding techniques.

1582. High Speed Magnetic Resonance Spectroscopic Imaging Using Wavelet Encoding and Parallel Imaging Yao Fu1, Hacene Serrai1 1National Research Council Institute for Biodiagnostics, Winnipeg, Canada

This work describes a new MRSI technique resulting from combination of wavelet encoding and parallel imaging. The purpose of this work is to reduce acquisition time in MRSI and minimize the SNR loss inherent to parallel imaging. Similar to Fourier encoding with parallel imaging where a predetermined number of k-space lines are skipped depending on the speed factor R, fewer lines in the wavelet domain, which resemble to k-space for wavelet encoding, are omitted and reconstructed from the acquired signals. As a result, reduction of acquisition time achieved by a factor R with minimum loss of SNR as compared to Fourier encoding.

1583. Optimal Number of Excitations for a Rosette Spectroscopic Imaging Experiment Claudiu Schirda1, Fernando Boada2 1State University of New York at Buffalo , Buffalo, New York, USA; 2University of Pittsburgh, Pittsburgh, Pennsylvania, USA

Fast spectroscopic imaging enables resolving the spectral information at much higher spatial resolutions compared to classical Chemical Shift Imaging (CSI) experiments, in shorter scan times. Besides fast CSI techniques that sample k-space on a Cartesian grid (e.g. Dixon), a number of non-conventional approaches employing non-Cartesian trajectories have been developed. Among them are stochastic trajectories, PREP, spiral and rosette trajectories. We theoretically analyze and experimentally demonstrate the off-resonance effects associated with these non-conventional encoding techniques.

1584. Breath-Hold High Resolution Spectroscopic Imaging of the Liver Using Rosette Trajectories Claudiu Schirda1, 2, Fernando Boada2 1State University of New York at Buffalo , Buffalo, New York, USA; 2University of Pittsburgh, Pittsburgh, Pennsylvania, USA

Nonalcoholic fatty liver disease (NAFLD) affects an estimated 14% to 30% of the general population in the United States, with an important number of these patients progressing to nonalcoholic steatohepatitis (NASH), cirrhosis or die of liver failure. The earliest manifestation of NAFLD/NASH is hepatic steatosis (fatty infiltration of the liver) and regrettably, the utility of liver biopsy is very limited. MRI techniques based on a two-point or multi-point Dixon methods were demonstrated for fat-water separation and fat fraction quantification in liver. However, FT based techniques are much more susceptible to even minimal amounts of motion compared to methods using center-out k-space trajectories. We propose the use of Rosette Spectroscopic Imaging (RSI) for fat-water separation in liver.

1585. Impact of T2* Decay on the Quantification of Hepatic Steatosis with MRI Venkata Veerendranadh Chebrolu1, Huanzhou Yu2, Ethan K. Brodsky1, Charles McKenzie, Scott B. Reeder1 1University of Wisconsin Madison, Madison, USA; 2GE Healthcare, Menlo Park, California , USA

This study investigates the impact of T2* decay on the ability of MRI using water-fat separation techniques to quantify fatty infiltration of the liver. A new generic analytical model, that includes the effects of line-width caused by T2* decay, is developed to the quantity the amount of different chemical species present in a specimen using MRI. The model is used to demonstrate the effect of line-width on the quantification of fat-fraction in non-alcoholic fatty liver disease. Our results demonstrate the need for methods that compensate for the effects of T2* decay when attempting to measure hepatic fat content.

1586. Comparison Between TmDOTP5- and TmDOTMA- Temperature Probes in Rat Brain Daniel Coman1, Fahmeed Hyder1 1Yale University, New Haven, USA

In the last decade, a new non-invasive method for temperature and pH determination was developed based on temperature and pH dependencies of the 1H chemical shifts emanating from TmDOTP5-. More recently a similar temperature-sensitive probe was introduced, based on temperature dependence of the methyl 1H chemical shift of TmDOTMA-, which is pH independent. Here we report detection of TmDOTMA- in the rat brain and compare in vivo temperature distributions obtained using TmDOTP5- and TmDOTMA- complexes. Additionally we discuss advantages and/or disadvantages of using these two complexes as exogenous probes for temperature and pH sensing in rat brain.

1587. Assessment of Lipids in Skeletal Muscle: Comparison of the Water and Fat Referenced Spectroscopy Jan Weis1, Lars Johansson1, Francisco Ortiz-Nieto1, Håkan Ahlström1 1Uppsala University Hospital, Uppsala, Sweden

The unsuppressed water line is almost exclusively used as a concentration reference in quantitation of the muscle lipids. In spectroscopy of the skeletal muscle, the necessity for relaxation correction of water reference is a fundamental disadvantage. Alternatively, the fat signal can be used as the internal standard. In this study we compare both methods for the determination of lipid content in human skeletal muscle: relaxation effects sensitive water referenced single-voxel 1H MRS and relaxation effects robust high-spatial-resolution MRSI with fat (yellow bone marrow) as the internal or vegetable oil as the external concentration reference.

Poster Sessions

274

1588. Design of Quality Control Measures for a Multi-Site Clinical Trial of Breast MRS - ACRIN 6657 Patrick J. Bolan1, Michael Garwood1, Mark A. Rosen2, Anthony Levering3, Jeffrey D. Blume4, James Gimpel3, Laura J. Esserman5, Nola Hylton5 1University of Minnesota, Minneapolis, Minnesota, USA; 2University of Pennsylvania, Philadelphia, USA; 3ACRIN, Philadelphia, USA; 4Brown University, Providence, Rhode Island, USA; 5University of California, San Franciso, San Francisco, California , USA

The American College of Radiology Imaging Network (ACRIN) and the I-SPY network are supporting a multi-site clinical trial using quantitative single voxel spectroscopy (SVS) to quantify early response to neoadjuvant therapy in 140 patients. Ensuring that the spectroscopic [tCho] measurements can be performed with sufficient accuracy and precision to address this clinical aim is a difficult challenge, especially considering that field strength, scanner manufacturer, breast coil, and sequences will vary between sites. The goal of this abstract is to describe the design of the study and its quality control measures and present initial findings from the quality control phantom scans.

1589. P-31 MRS for Detection of Myocardial Microvascular Disease in Latino Type-I Diabetes Mellitus Patients Hee-Won Kim1, Gerald M. Pohost1, Padmini Varadarajan2, Milena Ocon1, Rafit Drori3, Patrick Colletti1, Adina E. Zeidler1 1University of Southern California, Los Angeles, California , USA; 2Loma Linda University Medical Center, Loma Linda, California , USA; 3Hillel Yaffe Medical Center, Hadera, Israel

The change of high energy phosphate (HEP) level in the heart of Latino Type-1 diabetes mellitus (DM) patients was evaluated during rest and stress at 3T in order to identify impaired left ventricular function that is associated with reversible, exercise-induced metabolite alteration in Type-1 DM patients. The significant drop of PCr/ATP was found during handgrip stress among 28% of the patient compared with normal control. It may suggest systemic microvascular disorder as bioenergetic changes present among Type-1 DM patients and the non-invasive 31P cardiac MRS may facilitate the prediction of cardiomyopathy in such patients.

High Field Spectroscopic Quantitation & Methodology Hall D Monday 14:00-16:00

1590. LASER 1H-MRS Optimized for Prostate Spectroscopy with Low B1 Ronald Ouwerkerk1 1Johns Hopkins University School of Medicine, Baltimore, Maryland, USA

The fully adiabatic 1H-MRS LASER sequence was modified for use with lower B1s. Refocusing pulses were optimized for minimum threshold and maximum bandwidths. The LASER sequence with Optimized Pulses (LASEROP) was tested in simulation using Bloch equations, which showed a B1 threshold of about 20 μ]T for 4 kHz BW. On phantoms with body coil excitation and with body coil loads the sequence produced excellent spectra of a citrate-containing phantom at TE 39 ms requiring only 21 μ T peak B1 field. This is particularly useful for 1H-MRS of the prostate where the LASER sequence can provide spectra that are much easier to quantify.

1591. Semi-LASER 1H-MR Spectroscopic Imaging of the Human Brain at 7T Tom WJ Scheenen1, Dennis WJ Klomp1, Pierre-Francois van de Moortele2, Gregor Adriany2, Arend Heerschap1 1Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands; 2University of Minnesota, Minneapolis, Minnesota, USA

The semi-LASER pulse sequence is a combination of conventional non-adiabatic slice-selective excitation and double slice-selective refocusing by two pairs of adiabatic full passage pulses. Combined with an efficient 16 channel head coil the sequence can produce a 3D spin echo localized volume of interest at an echo time of 30 ms. With a small chemical shift displacement error and the relative insensitivity for B1 inhomogeneities, the semi-LASER technique is able to provide useful MR spectra over a large part of the brain at 7T without additional lipid or outer volume suppression.

1592. Proton Spectroscopy of Human Brain at 3T and 7T: Signal-To-Noise Ratio, Spectral Linewidth and Relaxation Times Yan Li1, 2, Duan Xu1, Albert P. Chen1, Daniel B. Vigneron1, Sarah J. Nelson1 1University of California, San Francisco, California , USA

The purpose of this study was to estimate the relaxation times of Cho, Cr and NAA at both 3T and 7T, to evaluate the effects of relaxation times in the long echo time acquisition, to examine the differences in SNR between 3T and 7T and to investigate how the acquisition parameters influence the quality of the spectra. Statistical significance was found for both T1 and T2 values of metabolites between 3T and 7T for all metabolites except for the Cho T1 value. After corrections for relaxation parameters, the SNR ratios between 7T and 3T were on average 1.53.

1593. High Spatial Resolution Short TE Proton-Echo-Planar-Spectroscopic-Imaging (PEPSI) in Human Brain at 7 Tesla Using B1-Compensation and Adiabatic Refocusing Tom WJ Scheenen1, Pierre-Francois van de Moortele2, Gregor Adriany2, Andre van der Kouwe3, 4, Ricardo Otazo5, Stefan Posse5 1Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands; 2University of Minnesota, Minneapolis, Minnesota, USA; 3Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, USA; 4Massachusetts General Hospital, Boston, Massachusetts, USA; 5University of New Mexico, Albuquerque, New Mexico, USA

Non-uniform spatial sensitivity, increased chemical shift displacement errors, lipid contamination due to B1-inhomogeneity, and increased RF power deposition are major challenges for metabolite imaging at ultra-high field (7T). In this study at 7T we combine Proton-Echo-Planar-Spectroscopic-Imaging with paired adiabatic refocusing pulses and B1-compensated outer volume suppression (OVS) to enable short TE (20 ms) metabolite mapping. We demonstrate the feasibility of high spatial resolution (0.25 cc voxel size) metabolite mapping in central and peripheral regions of the human brain in a clinically feasible measurement time using a 16-channel line array headcoil.

Poster Sessions

275

1594. 1H NMR T1 Relaxation Times of the Neurochemical Profiles in Rat Brain at 14.1T Cristina Cudalbu1, Vladimir Mlynárik, Lijing Xin, Rolf Gruetter, 2 1 Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland; 2Departments of Radiology, Universities of Lausanne and Geneva, Switzerland

The aim of the present study was to measure in vivo T1 relaxation times of the neurochemical profiles at 14.1T in rat brain. T1 measurements were accomplished using a progressive saturation technique, which was validated with an adiabatic inversion recovery. The T1 measured at 14.1 T is similar (~10%) to those measured at 9.4 and 11.7T suggesting that for metabolites, T1 increases are of minimal consequence beyond 9.4 Tesla.

1595. Selective Measurement of Brain Glutamate and Glutamine in Vivo by Spectrally-Selective Refocusing at 7T Changho Choi1, Chenguang Zhao1, Ivan Dimitrov1, 2, Ana Stan1, Carol Tamminga1 1University of Texas Southwestern Medical Center, Dallas, USA; 2Philips Medical Systems, Cleveland, Ohio, USA

Spectrally-selective refocusing has been applied to separate the signals between glutamate (Glu) and glutamine (Gln) in human brain selectively at 7.0 T. The C4-proton resonances of Glu and Gln, which differ by ~0.1 ppm ≈ 30 Hz), was selectively refocused using a 50-ms long Gaussian 180° pulse implemented within PRESS. Ignoring T1 and T2 effects, an optimal echo time of 137 ms gave Glu and Gln multiplets at 2.35 and 2.45 ppm with peak amplitude 67% and 53% with respect to 90°−acquisition respectively. Preliminary in vivo results from the human brain are presented.

1596. Analysis of 1H Metabolite Ratios Using Image Segmentation at 7T in Adult Patients with X-Linked Adrenoleukodystrophy Trina Kok1, Eva-Maria Ratai2, 3, Florian Eichler, 34, Elfar Adalsteinsson1 1Harvard-MIT Division of Health Sciences and Technology, Cambridge, Massachusetts, USA; 2A.A. Martinos Center for Biomedical Imaging, Cambridge, Massachusetts, USA; 3Harvard Medical School, Boston, Massachusetts, USA; 4A.A. Martinos Center for Biomedical Imaging,, Cambridge, Massachusetts, USA

The combination of segmented structural data with low-SNR spectroscopy has been used to provide brain metabolite estimates in separate tissue compartments [1-3]. To correct for comparison across subjects under different scanning conditions, expressing metabolite signals as ratios to the sum of the metabolite signals from Cr and PCR (Cr') is a common technique. We extend compartmental analysis of absolute metabolite measures to ratio measures, and demonstrate its use in a study of NAA+NAAG (NAA') changes in X-linked adrenoleukodystrophy at 7T

1597. Composition of Adipose Tissue and Marrow Fat by 1H MR Spectroscopy at 7 Tesla Jimin Ren1, 2, Ivan Dimitrov1, 3, A. Dean Sherry1, Craig Malloy1, 4 1University of Texas Southwestern Medical Center, Dallas, USA; 2Advanced Imaging Research Center, Dallas, USA; 3Philips Medical Systems, Dallas, USA; 4VA North Texas Health Care System, Dallas, USA

1H MR spectra were obtained from subcutaneous adipose tissue and bone marrow in the tibia in 10 healthy subjects at 7T. The ultra-high field spectroscopy offers a simple method to obtain detailed information about fatty acid composition, due to well-resolved proton resonances for all major structural fragments including –CH3, -(CH2)n-, -CH2-COO, -CH2-CH2-COO, -CH=CH-, -CH=CH-CH2-CH=CH, -CH2-CH2-CH=CH-, and in some instances from the methine and methylene protons of glycerol backbone. The composition of marrow and adipose fat were similar, ~24-26% polyunsaturated, 46-49% monounsaturated and 28-29% saturated. The estimated fraction of 16-carbon and 18-carbon fatty acids was about 32% and 68%, respectively.

1598. Proton Spectroscopic Imaging of the Human Prostate in Vivo at 7T Dennis Klomp1, Andreas Bitz2, Arend Heerschap1, Tom Scheenen1 1Radboud University Nijmegen, Medical Center, Nijmegen, Netherlands; 2Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen, Germany

To meet the demand for a better sensitivity in 1H MRSI of the prostate the magnetic field strength of 7T can be employed. We introduce the endorectal RF coil as a tranceiver, validate its safety for in vivo use and present a new pulse sequence optimzed for 3D MRSI of the human prostate at 7T. Safe use of the coil was validated with SAR calculations, MR thermometry and in vivo temperature monitoring. The pulse sequence was designed and validated with quantum mechanical simulations, phantom and in vivo measurements.

1599. Adiabatic T1ρ and T2ρ Relaxation Measurements of J-Coupled Spins. Results from Phantoms and from the Human Brain at 4T Silvia Mangia1, Michael Garwood1, Dennis Sorce1, Kamil Ugurbil1, 2, Shalom Michaeli1 1University of Minnesota, Minneapolis, Minnesota, USA; 23. Max Planck Institute for Biological Cybernetics, Tubingen, Germany

The phase modulation introduced by J-evolution complicates the analysis of spectra, and impairs the possibility of estimating relaxation rates of J-coupled spins. The phantom and in vivo results presented in this work demonstrate that rotating frame relaxation measurements (T1ρ and T2ρ) performed with specific configurations of adiabatic full passage pulses are not affected by J-evolutions. This notably simplifies the estimation of relaxation rates in the rotating frame also for resonances other than singlets. Since the analysis of the relaxation rates measured in the rotating frame can provide quantitative information on the spin dynamics, our results imply that dynamics of several compounds relevant for brain function and metabolism (as for instance glutamate) can be probed by adiabatic T1ρ and T2ρ relaxation measurements.

1600. Reproducibility of Cerebral Metabolite 1H T2 Relaxation Measurements at 3T Audrey Jennifer Chang1, Sergey Cheshkov1, Subhendra Sarkar1, Richard Briggs1 1UT Southwestern Medical Center, Dallas, Texas, USA

MR spectroscopy has become a valuable tool in the investigation of the pathologies underlying many neurodegenerative disorders. The goal of this study is to investigate the reproducibility of metabolite T2 relaxation time measurements in normal subjects at 3T, and to develop a standard protocol for acquisition of T2 relaxation measurements in neurodegenerative disease patients within a clinically feasible scan time (1 hr). In addition to influencing the ability to detect significant changes in cerebral metabolite concentrations, information about variation in time of T2 relaxation measurements might provide insight into molecular mechanisms of disease progression.

Poster Sessions

276

1601. In Vivo J-Difference Lactate Editing at 3.0 Tesla Mari A. Smith1, Jason A. Koutcher1, Kristen L. Zakian1 1Memorial Sloan-Kettering Cancer Center, New York, USA

The goal of this study was to implement in vivo detection of lactate by J-difference editing 1H MRS on a 3 Tesla human scanner for potential applications in patients. The current study extends the previous work cited in the literature regarding BASING editing for lactate detection by testing the sequence in the presence of high lipid concentrations in vivo at 3 T. The results demonstrate the ability of the BASING J-difference technique to detect lactate in the presence of strong lipid signals and indicate successful lactate editing in the presence of lipid at 3 T.

1602. Turbo Spin Echo Based Spatially Resolved Correlated Spectroscopic Imaging Gaurav Verma1, Saadallah Ramadan2, 3, Scott Lipnick1, Nagarajan Rajakumar1, M. A. Thomas1 1UCLA, Los Angeles, California , USA; 2Brigham & Women's Hospital, Boston, Massachusetts, USA; 3Harvard Medical School, Boston, Massachusetts, USA

The purpose of this study is to develop a turbo spin echo (TSE) based sequence for recording multi-voxel based 2D COSY MR Spectra. Through incorporating an echo train in each TR rather than a single acquisition, which has been routinely used in conventional MR Spectroscopic Imaging (MRSI), the data acquisition was accelerated by a factor of 4 or more, thus reducing the total duration required for recording 4 dimensional (4D) MRSI (2D Spatial, 2D Spectral) to times reasonable for adding this sequence to any clinical MRSI protocol.

1603. A Pilot Comparison of 2D and 1D MR Spectroscopic Quantitation of Metabolites in Healthy Human Brain at 3T Enrique Frias-Martinez1, Nagarajan Rajakumar1, S. Ramadan1, S. Banakar1, X. Liu1, A. Singhal1, Michael Albert Thomas1 1UCLA, Los Angeles, California , USA

Using a 3T MRI scanner, spatially resolved two-dimensional (2D) MR spectra including L-COSY and JPRESS, and one-dimensional (1D) PRESS spectra were recorded in the occipital white/gray matter regions of healthy human volunteers. ProFit algorithm was used to quantify the 2D MRS raw data and LC-Model for the 1D signal. Eight healthy volunteers and a white matter phantom have been investigated so far. Preliminary results indicate that COSY-ProFit provides better specificity that JPRESS-ProFit, and both of them provide better specificity and a higher number of detected metabolites than 1D PRESS processed using LC-Model.

1604. Tissue-Dependent Analysis of Metabolic Alterations in the Brain by MR Spectroscopic Imaging Andrew A. Maudsley1, Colin Studholme2, Varanavasi Govindaraju1 1University of Miami, Miami, Florida, USA; 2University of California San Francisco, San Francisco, California , USA

A method for analysis of single-subject metabolite images is presented that uses knowledge of the local tissue distributions and of the tissue-specific metabolite values generated from a group of comparison subjects. By incorporating spatial normalization procedures that convert all metabolite image results to a standardized space, this procedure enables voxel-based analyses without the requirement for accurate spatial alignment on the sulcal level.

1605. Assessment of Normative Metabolite Variations in Fronto-Cerebellar Voxels Using 1H MRS Kevin Wayne Waddell1, Parham Zanjanipour2, Subechhya Pradham1, James M. Joers1, Edward Brian Welch3, Peter R. Martin1, Malcolm J. Avison1, John C. Gore1 1Vanderbilt University, Nashville, USA; 2University of Kentucky, Lexington, USA; 3Vanderbilt University, Nashville, Tennessee, USA

The relationships of N-acetyl aspartate (NAA) and choline-containing compounds in the anterior cingulate and cerebellar vermis of chronic alcoholics have previously been studied using proton spectroscopy. Advances in clinically available high-field scanners have made it possible to measure levels of the major inhibitory neurotransmitter, gamma-aminobutyric acid (GABA), in these areas. We used these methods to establish normative fronto-cerebellar concentrations of metabolites using J-difference spectroscopy. We found that ratios of GABA* with respect to creatine are 140% higher on average than their cerebellar-vermian counterparts. Corresponding ratios of glutamate and NAA were also elevated in the anterior cingulate.

1606. The Roles of PCr in Brain Activity Mary C. Stephenson1, Kay E. Head1, Andrew M. Peters1, Dorothee P. Auer, Peter G. Morris1 1University of Nottingham, Nottingham, UK

Activation in the brain increases energy use but, due to the haemodynamic response there is a delay of a few seconds in the supply of additional glucose and oxygen. This study uses 31P spectroscopy to explore the possible role of PCr in meeting energy demand during this first few seconds of activation. Three seconds after the onset of intense visual stimulation we measured small increases in PCr, decreases in Pi and pH. These are consistent with the energy shuttle hypothesis but not a buffering role for PCr.

1607. Blipped Phase-Encoding in MR Spectroscopic Imaging Revisited: Comparison to SENSE-MRSI Peng Qu1, Joseph Gillen1, Peter B. Barker1, 2 1Johns Hopkins University, Baltimore, Maryland, USA; 2Kennedy Krieger Institute, Baltimore, Maryland, USA

Blipped phase-encoding (BPE) has previously been used to accelerate echo-planar spectroscopic imaging sequences. However, it apparently has not been applied to conventional magnetic resonance spectroscopic imaging (MRSI). This abstract describes the implementation of BPE-MRSI on 1.5 and 3.0T systems, and compares the results to those from sensitivity-encoded MRSI.

Poster Sessions

277

1608. Volumetric Spiral Chemical Shift Imaging with 32-Channel Receive Coil at 3T with Online Gridding Reconstruction Borjan Aleksandar Gagoski1, Michael Hamm2, Jonathan Polimeni3, 4, Gunnar Krueger5, Eva-Maria Ratai3, 4, Graham Wiggins3, 4, Uwe Boettcher6, Joonsung Lee1, Florian Eichler3, 4, Stefan Roell7, Elfar Adalsteinsson1, 8 1Massachusetts Institute of Technology, Cambridge, Massachusetts, USA; 2Siemens Medical Solutions, Charlestown, Massachusetts, USA; 3A. A. Martinos Center for Biomedic Imaging, Charlestown, Massachusetts, USA; 4Harvard Medical School, Boston, Massachusetts, USA; 5Siemens Medical Solutions, Lausanne, Switzerland; 6Siemens Medical Solutions, Erlangen, Germany; 7Siemens Medical Solutions, Malvern, Pennsylvania, USA; 8Harvard-MIT Division of Health Sciences and Technology, Cambridge, Massachusetts, USA

Coil arrays with large number of receive elements are well suited for the time-efficient CSI acquisitions, as they provide important SNR gain for metabolite detection. In this work we make use of the encoding efficiency of the spiral CSI to quickly encode 3D volumetric brain acquisitions with small voxel sizes. We use a custom-built 32-channel coil array to maximize SNR and fast online gridding reconstruction. We present in-vivo results demonstrating that combining the spiral CSI with large receive coil arrays yields large-volume, high-resolution spectroscopic imaging data.

1609. Proton-Echo-Planar-Spectroscopic-Imaging (PEPSI) Acquired Using Radial Trajectory (RPEPSI) Shang-yueh Tsai1, Yi-Ru Lin2, Teng-Yi Huang3, Stefan Posse4, 5, Fa-Hsuan Lin6, 7 1Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan; 2Dept. of Electronic Engineering, National Taiwan University of Science and Technology, Taiwan; 3Dept. of Electrical Engineering, National Taiwan University of Science and Technology, Taiwan; 4Dept. of Psychiatry, University of New Mexico, Albuquerque, New Mexico, USA; 5Dept. of Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico, USA; 6Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts, USA; 7MGH-HMS-MIT Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, USA

Proton Echo Planar Spectroscopic Imaging (PEPSI) has been developed to reduce the scan time of 2-dimensional MRSI to the order of several minutes. However the spectral quality may still be influenced by motion. Radial acquisition is known to be less sensitive to motion artifacts compared with Cartesian sampling scheme. Here a radial PEPSI (rPEPSI) sequence is implemented and compared with regular PEPSI. Spectra and metabolite maps quantified with LCModel from rPEPSI and PEPSI are comparable. The concentrations and fitting errors are at similar level. In this preliminary report, we demonstrate the feasibility to combine radial acquisition and PEPSI technique.

1610. Sensitivity Improvements in Peak Detection of Glutamate, GABA and Glutamine in the Human Brain Using ISIS CT-PRESS at 4.7 T Hidehiro Watanabe1, Nobuhiro Takaya1, Fumiyuki Mitsumori1 1National Institute for Environmental Studies, Tsukuba, Japan

A ISIS CT-PRESS sequence was implemented on a 4.7-T whole-body spectrometer for peak detection of glutamate, GABA and glutamine in the human brain with higher sensitivity. Three diagonal peaks of GABA C2H (2.28 ppm), Glu C4H (2.35 ppm) and Gln C4H (2.44 ppm) were resolved on CT-PRESS spectra of a phantom containing a brain mixture. Signal to noise ratio of Glu C4H on a CT-PRESS spectrum was 2.24 times higher than that obtained by localized CT-COSY. In volunteer studies, these three peaks were resolved on CT-PRESS spectra of parieto-occipital regions with sensitivity improvement by a factor of 1.7.

1611. Optimized CT-PRESS for Localized Proton NMR Spectroscopy of the Human Brain at 3 Tesla Wolfgang Dreher1, 2, Dmitry Ebel1, 2, Dieter Leibfritz1, 2 1University of Bremen, Bremen, Germany; 2Center for Advanced Imaging (CAI), Bremen, Germany

Different ways to optimize CT-PRESS measurements and maximize the SNR on a 3 T human head scanner are examined. Short tc values corresponding to the mean echo time are realized by using a short TE PRESS module and an additional rectangular 180 . Strong spoiler gradients make phase cycling obsolete and enable weighted averaging in t1. A local RF transmitter adjustment accounts for spatial B1 inhomogeneities and avoids severe signal losses by deviation from the nominal flip angles. Truncation artifacts can be reduced below the noise level for in vivo measurements by using the S-TRAF function for apodization in t1.

1612. The Reliability of Vitamin C (Asc) Detection in Human Brain Using Standard PRESS on a Clinical 3T MR-Scanner Yi-Yu Shih1, 2, Dominik von Elverfeldt2, Martin Buechert2, Hsiao-Wen Chung1, Juergen Hennig2 1National Taiwan University, Taipei, Taiwan; 2University Hospital Freiburg, Freiburg, Germany

The Asc concentration was successfully detected in 71 of 76 in vivo human brain spectra using PRESS sequence on 3T MR-scanner in our study. To further evaluate the reliability in quantification, three of the spectra with different line-widths were chosen to add artificial Asc spectrum (virtual titration) with different concentrations and SNR levels, followed by analysis via LCModel. The results show the good linearity between added and estimated concentrations of Asc. Other neighboring metabolites (mI and Glx) are only slightly affected (within 10% concentration change) if the line-width was less than 0.043 ppm. Therefore, it is feasible to detect Asc using standard clinical MRS acquisition in combination with LCModel.

1613. Signal Normalization for MR Spectroscopic Imaging Using an Interleaved Water-Reference Andrew A. Maudsley1, Claudia Domenig1 1University of Miami, Miami, Florida, USA

A signal normalization method for MRSI in the brain is described that uses a tissue water MRSI, obtained using an interleaved measurement, as an internal reference. When combined with spatial registration functions, this procedure enables voxel-based comparisons between repeated studies in the same subject as well as comparisons between subjects. Results for analysis of individual voxel results for intra-subject and inter-subject comparisons are presented, as well as for tissue regression analyses over different brain volumes.

Poster Sessions

278

1614. Applying Optimized Variable-Rate Excitation for Outer Volume Suppression in Fast 3D Proton Spectroscopic Imaging of the Human Brain at 3 Tesla Dmitry Ebel1, 2, Christian Schuster1, 2, Wolfgang Dreher1, 2, Dieter Leibfritz1, 2 1University of Bremen, Bremen, Germany; 2Center for Advanced Imaging (CAI), Bremen, Germany

Spectroscopic Missing-Pulse SSFP (spMP-SSFP) is a powerful method for fast 3D spectroscopic imaging. However, further improvements are hampered by specific absorption rate (SAR) and timing limitations. In this study, optimized RF and gradient waveforms were applied within spMP-SSFP to improve saturation of extracranial lipid signals. The number of applicable OVS slices was increased when applied on the human brain at 3 Tesla using VERSE-like 90 pulses, calculated by genetic algorithms, with reduced SAR and improved off-resonance behavior. This approach enables better defined regions of interest and will allow to implement spMP-SSFP at higher magnetic fields.

1615. Voxel Based Analysis and Reconstruction of Spectroscopic Imaging Data Jullie Pan1, Xenophon Papadametris1, Susan Spencer, Dennis Spencer1, Hoby Hetherington1 1Yale University, New Haven, Connecticut, USA

We have developed and implemented methods to identify and reconstruct spectroscopic imaging pixels using either a common anatomical atlas (MNI standard brain) and other imaging modalities (e.g. PET,CT and SPECT) to define the target locations. Co-registration driven selection and registration provides for precise positioning of the target voxels and the elimination of user bias in voxel selection. We have applied these methods to investigate: 1) the extent of asymmetric subcortical metabolic abnormalities in patients with temporal lobe epilepsy and 2) the relationship between regions with abnormal intracranial EEG (electrodes identified by CT) and decreased NAA in patients with neocortical epilepsy.

1616. Resolution Enhancement of Brain Glutamate at PRESS {TE1, TE2} = {35, 75} Ms at 3T Changho Choi1, Nicholas J. Coupland2, Peter Seres2, Chenguang Zhao1, Sanjay Kalra2, Philip G. Tibbo2 1University of Texas Southwestern Medical Center, Dallas, USA; 2University of Alberta, Edmonton, Canada

PRESS echo time dependence of brain glutamate (Glu) selectivity was investigated, with density-matrix simulation, for TE1 and TE2 between 30 and 80 ms, incorporating the neighboring resonances of glutamine, N-acetylaspartate and glutathione. The numerical calculation indicated that Glu signal intensity and resolution are both maximized at {TE1, TE2} = {35, 75} ms, its peak amplitude being 73% with respect to 90°−acquisition. An in vivo brain spectrum from these subecho times is presented, in comparison with a spectrum from the previously-proposed echo time {40, 40} ms.

1617. Lactate Edited 3D MR Spectroscopic Imaging of Gliomas at 3T Using Ellipsoidal SENSE with BASING Pulses Esin Ozturk-Isik1, Wei Bian1, Ilwoo Park1, 2, Albert P. Chen1, Jason C. Crane1, Daniel B. Vigneron1, 2, Susan M. Chang1, Sarah J. Nelson1, 2 1University of California at San Francisco, San Francisco, California , USA; 2University of California at San Francisco and Berkeley, San Francisco, California , USA

Lactate is an important metabolite that has been detected in high-grade brain tumors, ischemia and stroke cases. Lactate detection requires a special editing scheme like the J-difference technique using dual BASING pulses due to coresonant lipid peaks. The J-difference based lactate detection requires two cycles of spectral data acquisition which results in doubled scan time. In this study, we propose to use a fast data acquisition method, the ellipsoidal SENSE technique, with BASING pulses to acquire 3D lactate edited MRSI of brain tumor patients with the clinically feasible scan time of 9 min at 3T.

MRS Processing Hall D Tuesday 13:30-15:30

1618. Multivariate Statistical Mapping of Spectroscopic Imaging Data Karl Young1, Patrice Weber1, Varanavasi Govindaraju, Khema Sharma, Ammar Darkazanl, Colin Studholme1, Lawrence Hall, Andrew A. Maudsley, Norbert Schuff1 1University of California and VA Medical Center, San Francisco, California , USA

Voxelwise multivariate statistical mapping is introduced for analysis of spectroscopic imaging (SI) data. Applications to experimental SI data demonstrate that multivariate statistical mapping yields greater power for detection of regional metabolite alterations than univariate tests implying that multivariate statistical mapping should be used for SI whenever simultaneous changes of metabolites are expected.

1619. Semi-Parametric Estimation in Magnetic Resonance Spectroscopy: Automation of the Disentanglement Procedure Hérald Rabeson1, Hélène Ratiney2, Dirk van Ormondt3, Danielle Graveron-Demilly2 1Université Lyon 1, Villeurbanne, France; 2Université Lyon 1, Villeurbanne, France; 3Delft University of Technology, Delft, Netherlands

Magnetic Resonance Spectroscopy (MRS) is a unique tool for non-invasive in vivo detection and quantitation of metabolites. A point of concern is disentanglement of perturbing – macromolecules and lipid - signals from the wanted metabolite signals. Cramér-Rao bounds (CRBs) on the data-points of the perturbing signals are derived. Exploiting the attendant formulae, we show that it is possible to automate – for use in clinics – the disentanglement procedure in the metabolite quantitation algorithm ‘QUEST’, part of the freely available MRS software jMRUI.

1620. MRSTANK - A User-Friendly Yet Powerful Alternative Software Package for Spectral Processing Marc Rea1 1Charing Cross Hospital, London, UK

Here we present a novel software package that allows easy creation and cross referencing of user databases of clinical spectra. The user-friendly GUI provides access to powerful statistical methods including Principal Components Analysis, Independent Component Analysis, and Linear Discriminant Analysis.

Poster Sessions

279

1621. Web-Based Graphical User Interface for the GE MRS/MRSI Data with LCModel Cheng-Yun Hsu1, Cheng-Wen Ko1, Wei-Der Lui1, Martin Buechert2, Shang-Yueh Tsai3 1National Sun Yat-sen University, Kaohsiung, Taiwan; 2University Hospital Freiburg, Freiburg, Germany; 3National Taiwan University, Taipei, Taiwan

In this work we implemented an user interface based on web browser for LCModel access within an institution. It provides users a convenient approach to access LCModel and benefits the plug-in development due to the popularity of web scripts, e.g. PHP, Java, and HTML. We believe that this tool will be very helpful and valuable for MRS studies.

1622. 1H MRS Signal Calibration in Clinical Conditions Using a Non-Synchronized Reference Signal (Eretic II) Gabriela Hossu1, 2, Francois Kauffmann3, Guillaume Calmon2, Sebastien Davard2, Muriel Perrin2, Sebastien Saez4, Christophe Dolabdjian4, Pierre Denise5, Andre Sesboue6, Jean-Marc Constans5 1CAEN University Hospital, CAEN, France; 2GE Healthccare, BUC, France; 3University, CAEN, France; 4GREYC CNRS UMR 6072 ENSICAEN, CAEN, France; 5CAEN University Hospital, CAEN, France; 6University, CAEN, France

Developed by Barantin ERETIC method consists of adding and synchronizing a pseudo-FID and metabolite signals electronically produced to calibrate. We present a simpler method ERETIC-II not requiring any synchronization. The ERETIC signal was continuously sent and unprocessed 1H 1.5T PRESS short TE spectra were acquired in full temporal resolution without averaging and separately analyzed with SCI-MRS-LAB program. Intra-variability and inter-recording CV were respectively 0.5% and 0.2%, showing improvements variability compared to previous results. This ERETIC-II method decreases variability, avoid difficulties of synchronization, could be applied in CSI and contributes to quality control in order to improve variability quantification in pathologies.

1623. An Automatic Time-Domain Algorithm for the Quantification of in Vivo Non-Water-Suppressed MR Spectroscopy: The Filter-Diagonalization Method (FDM) Jyh-Miin Lin1, Shang-Yueh Tsai1, Hua-Shan Liu1, 2, Hsiao-Wen Chung1, Chou-Ming Cheng3, Tzu-Chen Yeh3, Robert V. Mulkern4, Nan-Kuei Chen5 1Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan; 2Department of Radiology, Tri-Service General Hospital and National Defense Medical Center, Taipei, Taiwan; 3Taipei Veterans General Hospital, Taipei, Taiwan; 4Department of Radiology, Children's Hospital and Harvard Medical School, Boston, Massachusetts, USA; 5Brain Imaging and Analysis Center, Duke University, Durham, North Carolina, USA

It has been shown that the metabolite signals can be quantified more accurately using the non-water-suppressed (NWS) MRS technique, in which the water signals are fitted and removed in post-processing, because (1) the metabolite signals are not distorted by water suppression pulses and (2) the un-suppressed water serves as an internal reference for metabolite quantification. Here we propose to use the Filter-Diagonalization Method (FDM), an algorithm originally developed for quantum dynamic computation, to reliably and automatically quantify the metabolite signals in NWS MRS data with a very economic computational cost. In comparison to the existing post-processing methods, FDM has a much better localization property and can be applied to analyze a selected spectral range. Results from our simulation, phantom, and in vivo MRS studies demonstrate that the proposed technique is superior to the existing NWS MRS data processing methods

1624. Refinement of Simulated Basis Set for LCModel Analysis Ivan Tkac1 1Univervity of Minnesota, Minneapolis, Minnesota, USA

Simulated bases set for LCModel analysis was refined using phantom metabolite spectra and highly resolved in vivo spectra from the rat brain at 9.4 T. Metabolite quantification using the new simulated basis set is in excellent agreement with the quantification performed using the experimental basis set. In addition, CRLB were significantly reduced. This update is mainly important for the weakly represented metabolites, such as Asc, Glc and GSH.

1625. Gaussian Mixture Model Estimation Using the Expectation Maximization Algorithm for MRS Inversion-Recovery Signals Hélène Ratiney1, Adriana Bucur1, Cristina Cudalbu1, Sophie Cavassila1 1CNRS UMR 5220, Inserm U630, INSA-Lyon, Université Lyon 1, Villeurbanne, France

The MR spectroscopic macromolecular signal, usually considered as a nuisance contribution in the quantification of short echo time signals, might reveal some interest as a disease marker by itself. Enabling its objective quantification and deriving a model function for its description is the purpose of the proposed method. Inversion recovery macromolecular spectrum coming from unresolved proteins, lipids and residual water shows broad patterns close to a gaussian mixture model. The proposed method takes advantage of the Expectation Maximization (EM) algorithm usually applied in machine learning or pattern recognition to provide a novel fitting procedure for broad patterns MR spectroscopic signal.

1626. Lineshape Accommodation in Quantitation of Magnetic Resonance Spectroscopy Signals Emil Popa1, Hérald Rabeson1, Dirk van Ormondt2, Danielle Graveron-Demilly1 1Université Lyon 1, Villeurbanne, France; 2Delft University of Technology, Delft, Netherlands

Lineshape distortions due to residual eddy currents and magnetic field inhomogeneities are often present in short echo-time 1H spectroscopic data. If left uncorrected, these lineshape distortions lead to errors in metabolite concentration estimates when using quantification methods that incorporate model functions with specific lineshapes. In this study a new method is investigated, namely, the lineshape of the simulated metabolite basis-set signals is given the estimated lineshape of a reference spectrum before the quantitation step. Analytical formulae for the Cramér-Rao lower bounds on model function parameters of a Lorentzian and Gaussian singlet are also derived.

Poster Sessions

280

NMR of Cells, Body Fluids & Other Hall D Wednesday 13:30-15:30

1627. Assessment of Fulminant Hepatic Failure and Liver Grafts by 1H NMR Spectroscopy of Serum Pratima Tripathi1, Ashish Gupta1, Raja Roy1, S K. Mandal1, Rajan Saxena2, S K. Yachha2, Chunni Lal Khetrapal1 1Centre of Biomedical Magnetic Resonance, Lucknow, India; 2Sanjay Ghandhi Post-graduate Institute of Medical Sciences, Lucknow, India

1H NMR spectroscopy has been used to study the metabolic profile of serum in Fulminant Hepatic Failure (FHF) patients and liver grafts (LG). Both in FHF and LG concentrations of alanine, lysine, glutamine, tyrosine, histidine and phenylalanine were significantly elevated in fatal cases when compared to recovered cases. Additionally in LG lactate, methionine and citrate were significantly more in fatal cases compared to successful cases. Principal Component Analysis showed lysine, glutamine, tyrosine and histidine to be the early discriminants for predicting the status of both FHF and LG.

1628. Metabolic Profiling of Renal Cell Carcinoma Studied by High-Resolution 1H NMR Spectroscopy on Human Serum in Combination with Multivariate Data Analysis Hongchang Gao1, Baijun Dong2, Xia Liu1, Yiran Huang2, Donghai Lin1 1Shanghai Institute of Materia Medica, the Chinese Academy of Sciences, Shanghai, People's Republic of China; 2Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, People's Republic of China

1H NMR-based metabonomics was applied in human serum samples to characterize the metabolic profiling of the renal cell carcinoma (RCC) tumor. The results showed that (a) the early RCC patients can be well distinguished from the healthy humans, and (b) the RCC patients after nephrectomy can be discriminated well from those before nephrectomy. Compared to healthy human serum, the RCC serum displayed higher levels of lipid (mainly very low-density lipoproteins), lactate, alanine, pyruvate, glycerol, and unsaturated lipid, but declined levels of acetoacetate, choline, and glucose/glycogen. Such systemic changes of metabolite concentrations were reversed after nephrectomy.

1629. Study on Vanadyl Sulfate Toxicity Using NMR-Based Metabonomics Jiyang Dong1, Xiaoxia Dai1, Hongting Cao1, Zhong Chen1 1Xiamen University, Xiamen, People's Republic of China

This study investigated the toxicity effects of VOSO4 oral administration in male Wistar rats using 1H NMR-based metabonomic analysis and clinical chemistry analysis. Urine was collected and their 1H NMR spectra were acquired, and then subjected to multi-variable statistical analysis. Compared to control groups, urinary excretion of lactate, TMAO, creatinine, taurine and hippurate increased following VOSO4 dosing, with concomitant decrease in the level of acetate and succinate. The dosed groups can be readily discriminated from the controls by principle component analysis. All of the results show that VOSO4 can affect energy metabolism process and induce hepatic and renal lesion.

1630. Phospholipid Composition of Postmortem Schizophrenic Brain by 31P NMR Spectroscopy Richard A. Komoroski1, 2, John M. Pearce1, 2, Robert E. Mrak2 1University of Cincinnati, Cincinnati, Ohio, USA; 2University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA

Cell membrane abnormalities due to changes in phospholipid (PL) composition and metabolism have been implicated in schizophrenia pathogenesis. High resolution 31P NMR spectroscopy was used to characterize PLs of gray matter in three regions of postmortem brain for 20 schizophrenic and 20 control subjects. There were no statistically significant differences (p<0.05) between the groups for any of the individual PLs. The sum of all phosphatidylethanolamine headgroups was significantly lower (p=0.047) for schizophrenics than for controls in frontal cortex. The present results are minimally correlated with previous results for aqueous PL metabolites on these same samples.

1631. Non-Invasive Diagnosis of Type II Diabetes Based on Non-Glucose Regions of 1H NMR Spectrum of Urine: A Metabolomics Approach Alina Nicolescu1, Tedros Bezabeh2, Brion Dolenko2, Lorena Ivona Stefan3, Coziana Ciurtin4, Eugenia Kovacs5, Ian C. P. Smith2, Calin Deleanu6 1 “Petru Poni” Institute of Macromolecular Chemistry, Iasi, Romania; 2Institute for Biodiagnostics, National Research Council, Winnipeg, Canada; 3Craiova Clinical Hospital, Craiova, Romania; 4 “Dr. I. Cantacuzino” Clinical Hospitat, Bucharest, Romania; 5 “Carol Davila” University of Medicine and Pharmacy, Bucharest, Romania; 6Institute of Organic Chemistry, Bucharest, Romania

While 1H NMR spectroscopy of urine can detect glucose in patients with type II diabetes mellitus, such information may not help much for the early diagnosis of diabetes. Changes in other metabolites present in urine may precede glucosuria and 1H NMR spectroscopy can play a role in the assessment of such changes. In patients already exhibiting glucosoria, the spectrum is dominated by signals from glucose. In such instances, conventional methods of analysis are not helpful. In this study, the use of a statistical classification strategy (SCS) has resulted in high accuracy in classifying urine spectra of normal controls from those of diabetic patients using the non-glucose spectral regions.

1632. High Resolution Nmr Based Analysis of Serum Lipids in Duchenne Muscular Dystrophy Patients and Its Possible Diagnostic Significance Niraj Kumar Srivastava1, Sunil Pradhan1, Balraj Mittal1, Raja Roy2 1Sanjay Ghandhi Post-graduate Institute of Medical Sciences, Lucknow, India; 2Center of Biomedical Magnetic Resonance, Lucknow, India

Lipid extract of serum of thirty-one clinically, genetically and biochemically proven Duchenne Muscular Dystrophy patients (DMD) was studied by 1H NMR spectroscopy. Triglycerides, phospholipids, free-cholesterol, cholesterol-esters and total cholesterol were 2 to 3 times higher in DMD patients than controls. Ratio of free-cholesterol to cholesterol-esters was also significantly higher. Ten cases of DMD that showed negative gene-deletion-test due to point-mutation, demonstrated similar lipid profile like proven-cases in NMR analysis. Among all these variables, there was a consistent increase in the quantity of phospholipids in DMD patients when compared to controls. These observations indicate the potential of NMR to discriminate DMD.

Poster Sessions

281

1633. Multiple-Oocyte in Vivo Localized MR Spectroscopy Verena Hoerr1, Armin Purea1, Cornelius Faber1 1University of Wuerzburg, Wuerzburg, Germany

A novel approach to intracellular MR spectroscopy, which combines solvent-localized (SOLO) NMR with chemical shift reagents, allowed for recording of intracellular MR spectra from a sample with 100 Xenopus leavis oocytes. Upon selective excitation of either intra or extracellular water signal, only intra or extracellular components were observed, respectively. SOLO afforded a 30-fold sensitivity gain compared to PRESS. Since only a single-axis gradient is required, the method was also implemented on a high-resolution NMR-system with cryo-probe. The method is readily applicable on most NMR spectrometers, making novel applications in pharmaceutics and developmental biology possible.

1634. Development of the Layered Dumbbell Shape Phantom for MRS Quality Assurance Dong-Cheol Woo1, Sang-Soo Kim1, Hyang-Shuk Rhim1, Hyun-Man Baik2, Orhan Nalcioglu2, Geon-Ho Jahng3, Bo-Young Choe1 1The Catholic University of Korea, Seoul, Republic of Korea; 2University of California, Irvine, Irvine, USA; 3East-West Neo Medical Center, Kyung-Hee University, Seoul, Republic of Korea

The purpose of this study was to develop a standard MRS phantom, to establish a QA protocol with principal factors and to perform QA of an MR system. For the QA of MRS, seven principal factors were selected and measured. The form of the phantom was made of acrylic resin and the layered dumbbell shape vial was filled with various metabolite and all experiments were performed on two 3T systems. All MRS QA factors of each MRI/MRS system were calibrated. The follow-up study showed that the QA factor values in September 2007 were superior to those obtained in June 2007.

1635. Silicon-Cylinder Nano Liter NMR-Probe for Biomedical Analysis Systems Stefan Leidich1, Thomas Riemer2 1Chemnitz University of Technology, Chemnitz, Germany; 2University of Leipzig, Leipzig, Germany

We present a new NMR-micro-probe designed for the analysis of sample volumes in the range of 10 nl to 50 nl. It is based on spiral micro-coils in a Helmholtz configuration which is housed in a silicon cylinder for susceptibility matching purpose.

1636. Development of a Diagnostic Test Based on Nanoscale Distance Measurements Between the Fatty Acid Binding Sites in Human Serum Albumin Dariush Hinderberger1, Marcos Gelos2 1Max Planck Institute for Polymer Research, Mainz, Germany; 2Augusta-Kranken-Anstalt, Bochum, Germany

We characterize the affinity of the fatty acid binding sites by exposing HSA in different ratios to paramagnetic fatty acids spin labels. We employ double-electron-electron resonance (DEER), a modern method of pulse EPR that measures dipolar couplings between individual spin labels. Through the known r-3-dependence of the dipolar coupling the distances r between the spin labels are obtained. Data analysis is so far in an experimental stage but we aim at standardizing the method and developing it into a diagnostic tool by expanding the studies from simple HSA in solution to actual blood samples from patients with different disease backgrounds.

Quantitative MRS of Glutathion 2 13C Labeled Metabolites Hall D Thursday 13:30-15:30

1637. Adaptive Spectral Registration Method for Glutathione Measurement Using J-Difference Editing Li An1, Yan Zhang1, David M. Thomasson1, Lawrence L. Latour1, Eva H. Baker1, Jun Shen1, Steven J. Warach1 1National Institutes of Health, Bethesda, Maryland, USA

In this work, we present a fully automated spectral registration method for frequency, phase, and linear baseline corrections. Instead of using a Lorenzian and/or Gaussian curve, target spectra for spectral registrations are generated from the data by a fitting and selection process. Spectral registrations are performed using broader ranges of spectral data instead of just one peak in the spectrum. A linear baseline correction is also done in the spectral registration process, which is important for GSH measurement where residual water baseline is a bigger problem than for other J-difference editing experiments.

1638. Strategy for Yield Enhancement in Glutathione Double-Quantum Filtering Changho Choi1, Nicholas J. Coupland2, Peter Seres2 1University of Texas Southwestern Medical Center, Dallas, USA; 2University of Alberta, Edmonton, Canada

A new strategy for yield enhancement of glutathione (GSH) double-quantum (DQ) filtering for detection of the 2.95-ppm resonances is proposed. Following the double-quantum preparation and DQC encoding, a spectrally-selective 180° RF pulse is employed to interchange DQC and ZQC, followed by another DQC encoding step. With the large bandwidth of adiabatic 180° pulses for space localization, an edited signal amplitude ~100% with respect to the 90°−acquired multiplet can be achieved at an optimal sequence time. Preliminary results of numerical simulation and phantom tests are presented.

1639. A New Strategy to Measure Reduced Glutathione (GSH) at 3 and 4 Tesla Using an Optimized STEAM Sequence Shaolin Yang1, Yihong Yang1 1National Institute on Drug Abuse, NIH, Baltimore, Maryland, USA

The reduced form of glutathione (GSH) is a major intracellular antioxidant. Due to its strong spectral overlap with other metabolites, spectral editing or LCModel analysis of short-echo PRESS or STEAM spectra has been suggested to measure GSH. We propose here a new strategy to resolve the spectral overlap between GSH and other metabolites by optimizing the timing parameters of a standard STEAM sequence through spectral simulation. The results show that the proton resonances of GSH at 2.54 ppm can be resolved from other metabolite resonances at 3T and 4T, which provides a potential to significantly improve the quantification of GSH.

Poster Sessions

282

1640. Practical Glutathione Measurement in Human Brain at 3 T Li An1, Yan Zhang1, David M. Thomasson1, Lawrence L. Latour1, Eva H. Baker1, Jun Shen1, Steven J. Warach1 1National Institutes of Health, Bethesda, Maryland, USA

This work demonstrates the ability to consistently measure GSH in human brain on a commercial 3 T scanner with a scan time of nine minutes. A relatively long TE of 131 ms yields good GSH signal, smaller water baseline, as well as near in-phase GSH and co-edited NAA/NAAG resonances. A novel spectral registration method was also developed to perform frequency, phase, and linear baseline corrections without human intervention. From scanning normal volunteers and stroke patients, this work appears to be a step forward toward practical use of GSH measurement in clinical studies.

1641. Simultaneous Detection of Antioxidant Concentrations and Their T2 Using Double Edited 1H MRS Melissa Terpstra1, Dinesh Deelchand1, Ivan Tkac1, Pierre-Gilles Henry1 1University of Minnesota, Minneapolis, Minnesota, USA

Quantification of ascorbate (Asc) and glutathione (GSH) concentrations may be useful to study neurodegenerative disease. T2 might differ between patients and controls. The goal of this study was to measure T2 along with Asc and GSH concentrations in the human occipital cortex in vivo. Asc and GSH resonances were detected at multiple echo times using DEW MEGA-PRESS edited 1H MR spectroscopy at 4 T. Reasonable T2 were measured in one subject without compromising signal to noise for detection of Asc and GSH. Data can be averaged over several subjects to reduce uncertainty in measurement of T2.

1642. Direct Measurement of Malate-Aspartate Shuttle Activity at Different Cytosolic Redox States in Intact Hearts Using 13C NMR Spectroscopy Ming Lu1, 2, Suhanti Banerjee1, Gerald M. Saidel1, Xin Yu1 1Case Western Reserve University, Cleveland, USA

To examine the effect of cytosolic redox state (NADH/NAD+) on malate-aspartate (M-A) shuttle activity in hearts, oxidative cardiac metabolism was studied using 13C NMR spectroscopy. Isolated rat hearts were perfused with either 2.5mM [2-13C]acetate or 2.5mM [2-13C]acetate plus glucose and lactate to increase cytosolic NADH/NAD+. Tricarboxylic acid (TCA) cycle flux (VTCA) and M-A shuttle flux (VM-A) were determined by least-square fitting of a novel multi-domain kinetic model of cardiac metabolism to dynamic 13C NMR spectra. Our results showed that VTCA was unaltered by changes in cytosolic redox state, whereas VM-A increased by 38% at high cytosolic NADH/NAD+.

1643. Mathematical Model of Glial Metabolism Assessed Using C1-Labeled Acetate Bernard Lanz1, Kai Uffmann1, Matthias T. Wyss2, Bruno Weber2, 3, Alfred Buck2, Rolf Gruetter1, 4 1Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; 2PET Center, University Hospital Zurich, Zurich, Switzerland; 3University Zurich, Zurich, Switzerland; 4Universities of Lausanne and Geneva, Lausanne and Geneva, Switzerland

Combining PET and NMR for cerebral labeling studies in vivo requires a common model to compare and combine the results given by both techniques. The aim of the present study is to develop a metabolic model of neuro-glial metabolism suitable to assess metabolic rates resulting from an infusion of acetate labeled at the C1 position and to apply this model to experimental radiotracer time courses following 11C[1]-acetate infusion. We developed and applied successfully a model based on traditional NMR modeling to simulate and fit PET data.

1644. Simultaneous Measurement of Neuronal and Glial Metabolism in Rat Brain In Vivo Using Co-Infusion of [1,6-13C2]Glucose and [1,2-13C2]Acetate Dinesh K. Deelchand1, Chris Nelson1, Alexander A. Shestov1, Kamil Ugurbil1, Pierre-Gilles Henry1 1University of Minnesota, Minneapolis, Minnesota, USA

In this work the feasibility of measuring neuronal-glial metabolism in rat brain in vivo using co-infusion of [1,6-13C2]glucose and [1,2-13C2]acetate was investigated. The distinct 13C spectral pattern observed in glutamate and glutamine directly reflected the fact that glucose was metabolized primarily in the neuronal compartment and acetate in the glial compartment. Time courses of concentration of singly and multiply-labeled isotopomers of glutamate and glutamine were obtained. We expect that dynamic metabolic modeling of these new 13C isotopomer data using two-compartment neuronal-glial models will lead to a more precise determination of metabolic rates, particularly the rate of glutamate-glutamine cycle.

Molecular Imaging Agents: Applications & Detection Hall D Monday 14:00-16:00

1645. Longer in Vivo Retention and Accumulation Improves Detection of PARACEST MRI Contrast Agents M. Meser Ali1, M. D. Pagel1 1Case Western Reserve University, Cleveland, Ohio, USA

PARACEST MRI contrast agents suffer from poor temporal resolution and limited detection sensitivity. Agents with longer in vivo retention times may compensate for poor temporal resolution, and agents that accumulate at high concentrations within in vivo tissues may compensate for limited sensitivity. The PARACEST agent EuDOTA-OBnS2-Gly2-COOH has both of these advantages relative to EuDOTAMGly, due to the addition of two o-benzyl moieties. This was demonstrated by the detection of the PARACEST effect of EuDOTA-OBnS2-Gly2-COOH in the in the inferior vena cava, kidney, and liver of a normal mouse.

1646. Heteronuclear Relaxivity of Commercial Gadolinium Contrast Agents Cristina Gabellieri1, Geoffrey S. Payne1, Martin O. Leach1, Thomas R. Eykyn1 1The Institute of Cancer Research, Sutton, UK

Development of hyperpolarisation techniques have led to increasing interest in non-proton MR for metabolic and molecular imaging. Potential biomarkers with nuclei with long relaxation times are needed to effectively use the high non-equilibrium polarization attained. Here we report relaxivities of two Gd-based contrast agents on 13C in glycine and 15N in choline in aqueous solutions. We also confirm that extracellular contrast agents exert little influence on the relaxation properties of intracellular metabolites by looking at cell suspension by 31P NMR of . This may be important in the future use of hyperpolarized tracers to relax the extracellular parent signal and better observe the intracellular daughter compounds.

Poster Sessions

283

1647. Improved Molecular Imaging of Sparse Neovascular Biomarkers with a Novel Lipophilic Gd-DOTA Chelate on Targeted Nanoparticles Patrick M. Winter1, Shelton D. Caruthers1, Anne H. Schmieder1, Todd A. Williams1, Dennis Riley, William McGhee, Samuel A. Wickline1, Gregory M. Lanza1 1Washington University, St. Louis, Missouri, USA

The purpose of this study was to compare the relaxivity and in vivo signal enhancement of targeted nanoparticles formulated with two different paramagnetic chelates, Gd-DTPA-BOA and Gd-DOTA-Amide-PE. Nanoparticles were targeted to the α ν β 3-integrin for molecular imaging of angiogenesis induced by tumor growth. The Gd-DOTA-Amide-PE nanoparticles had 50% higher relaxivity and produced 74% higher enhancement in a rabbit tumor model. These results suggest that paramagnetic chelates with improved relaxivity may facilitate increased sensitivity with molecular imaging agents.

1648. In Vivo Imaging of α vβ 3 - Targeted Micellar Nanoparticles in an NSCLC Tumor Xenograft Model by Off-Resonance Saturation Method Chase W. Kessinger1, Chalermchai Khemtong1, Jimin Ren1, Erik A. Bey1, David A. Boothman1, A. Dean Sherry1, Jinming Gao1 1University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA

Here we describe the use of off-resonance saturation (ORS) method to image α v β 3 - targeted superparamagnetic polymeric micelles (SPPM) for the molecular imaging of cancer. The ORS contrast is achieved by water signal attenuation with an RF pulse set at an off-resonance position to bulk water. The ORS method was demonstrated in a human NSCLC tumor xenograft model in nude mice in vivo. The ORS contrast can be turned “on” and “off”, to produce an accurate contrast image of superparamagnetic nanoparticles targeting to tumor neovasculature.

1649. Intracellular Uptake of Targeted Paramagnetic Contrast Agent Leads to Quenching of T1 Contrast Maarten B. Kok1, Sjoerd Hak1, Willem J.M Mulder2, Daisy van der Schaft1, Gustav J. Strijkers1, Klaas Nicolay1 1Eindhoven University of Technology, Eindhoven, Netherlands; 2Mount Sinai School of Medicine, New York, USA

This study shows that the effective relaxation enhancement introduced by an internalized paramagnetic contrast agent depends crucially on its intracellular localization. The effective T1 relaxivity of internalized áíâ3-targeted liposomes was much lower than that of non-targeted liposomes. This finding has important implications for the interpretation of target specific MRI in vivo, as significant local uptake of contrast agent by target tissue might go undetected.

1650. Novel Method to Characterize Paramagnetic Contrast Agents Association to 2-Dimensional Surfaces H.M.H.F. Sanders1, H.P. Huinink1, S.J.F. Erich1, O.C.G. Adan1, M. Merkx1, G. J. Strijkers1, K. Nicolay1 1Eindhoven University of Technology, Eindhoven, Netherlands

Receptor mapping of cells lining blood vessels is a major application of molecular MR imaging using targeted contrast agents, for example for atherosclerosis or angiogenesis characterization. Here we show that very high-resolution MRI depth profiling by using a saturation recovery pulse sequence, combined with mathematical modelling, is capable of quantifying the surface water longitudinal relaxation rate induced by a surface-bound contrast agent. This technique is helpful in studying the behavior of targeted contrast agents and will yield valuable insights for the optimization of the MRI-based detection of target-associated contrast agents.

1651. Imaging Targeted Delivery of Liposomes to Tumor Vasculature Maria Mikhaylova1, Amin Hajitou2, Yoshinori Kato1, Saraswati Sukumar, Dmitri Artemov1, Marie-France Penet1, Wadih Arap2, Renata Pasqualini2, Zaver M. Bhujwalla1 1JHU ICMIC Program, The Johns Hopkins University, School of Medicine, Baltimore, Maryland, USA; 2The University of Texas, MD Anderson Cancer Center, Houston, Texas, USA

We recently identified a novel peptide that binds specifically to breast cancer vasculature. Here we have examined the potential of this peptide for targeting multifunctional liposomes to tumor vasculature in an MDA-MB-231 human breast cancer model. In vivo magnetic resonance imaging revealed specific accumulation of targeted liposomes in tumor vasculature starting at 3h following intravenous injection compared to liposomes with a control peptide. This finding was supported by optical imaging and immunofluorescent localization. These data suggest that the newly identified peptide may provide a means to deliver therapeutic and analytical cargo to breast cancers under image-guidance.

1652. Targeted Herceptin-Dextran Nanoparticles for Noninvasive Imaging of Her2/neu Receptor by MRI Yun-Ming Wang1, Ting-Jung Chen1, Chiao-Yun Chen2, Gin-Chung Liu2 1Kaohsiung Medical University, Kaohsiung, Taiwan; 2Kaohsiung Medical University Hospital, Kaohsiung, Taiwan

The fabrication and characterization of dextran-coated magnetic nanoparticles CLIO-Herceptin as nanoprobes for MR imaging to target specific receptors were reported. From the results, we found that the CLIO-Herceptin had well-dispersed in different pH value solutions, low protein absorption from medium, no hysteresis, high saturation magnetization and low cytotoxicity of different cells. Moreover, CLIO-Herceptin had ability to target the SKBR-3, BT-474, MDA-MB-231 and MCF-7 cells proved by in vitro and in vivo MR imaging studies.

1653. Molecular MRI of the Estrogen Receptor in Human Breast Cancer Cells Adi Pais1, Chidambaram Gunanathan1, David Milstein1, Hadassa Degani1 1Weizmann Institute of Science, Rehovot, Israel

The estrogen receptor (ER) serves as an important prognostic factor and a marker for predicting response to hormonal therapy. We present two novel contrast agents targeted to ER, composed of a gadolinuimpyridiniumtetraacetate conjugated to estradiol (EPTA-Gd), or to tamoxifen (TPTA-Gd) both with a micromolar binding affinity to ER. These agents exhibited agonistic effect on cell proliferation, disparity in inducing ER degradation and high relaxivities in solution. Concentration dependent studies of T1 and T2 relaxation in viable ER+ cells and in the same cells with null ER indicated a specific binding to ER which reflected the level of this receptor.

Poster Sessions

284

1654. Molecular Imaging of Benfluorex Treatment in Diabetic Rats with α vβ 3-Integrin Targeted Nanoparticles Kejia Cai1, Todd A. Williams1, Shelton D. Caruthers1, 2, Gregory M. Lanza1, Samuel A. Wickline1, Patrick M. Winter1 1Washington University, Saint Louis, Missouri, USA; 2Philips Medical Systems, Andover, Massachusetts, USA

The metabolic syndrome is highly associated with cardiovascular disease. JCR:LA-cp diabetic rats were treated with benflurorex for 15 weeks to study the effects on cardiovascular disease. ávâ3-integrin targeted gadolinium nanoparticles were used for molecular imaging of angiogenesis, a hallmark of atherosclerosis. Benfluorex treatment decreased MR signal enhancement by about 60%, indicating suppression of angiogenesis, and possibly inhibition of atherosclerosis. These results suggest that molecular imaging with targeted nanoparticles can detect cardiovascular disease associated with metabolic syndrome and monitor the treatment response.

1655. Evaluation of Sensitivity Increase by T1 and T2 Contrast Agents in 19F MRI of PF15C Thomas Christian Basse-Luesebrink1, Thomas Kampf2, Christian Herbert Ziener2, Gert Klug2, Wolfgang Rudolf Bauer2, Peter Michael Jakob2, Daniel Haddad1 1Research Center Magnetic Resonance Bavaria, Wuerzburg, Germany; 2University of Wuerzburg, Wuerzburg, Germany

In this study the influence of T1 and T2 contrast agents in 19F MRI on SNR per measurement time is investigated. Therfore Turbo Spin Echo (RARE) and Fast Gradient Echo (FLASH) sequences are applied to different cases. As a result this study suggests that the usage of T1 contrast agents is not generally preferable.

1656. On the Optimal Field Strength for Detection of Targeted Gd-Based Contrast Agents in Molecular MR Imaging Olivier Girard1, Philippe Robert2, Luc Darrasse1 1Univ Paris-Sud, CNRS, Orsay, France; 2Guerbet Recherche, Roissy Charles-De-Gaulle, France

Molecular MR Imaging using targeted Contrast Agents (tCA) is a promising tool for early diagnosis purpose. For macromolecular Gd-based CA (e.g. a tCA bound to its target) the T1-relaxivity tends to decrease rapidly above 20-30 MHz raising the question of their efficiency at high field. We investigate theoretically and experimentally the Contrast-to-Noise Ratio (CNR) obtained with a paramagnetic tCA as a function of the field strength, accounting for NMRD profiles derived from experimental data. Results indicate that Molecular MR Imaging with Gd-based tCA do not benefit from high field strength and should be performed around 1-1.5 T to optimise the CNR and differentiate bound and free pools of tCA.

1657. Early Stage Investigations of USPIO-Induced Signal Changes After Focal Cerebral Ischemia in Mice Virginie Desestret1, Jean-Christophe Brisset1, Emilie Devillard1, Samir Moucharrafie1, Serge Nataf2, J. Honnorat2, Norbert Nighoghossian1, Yves Berthezene1, Marlène Wiart1 1Creatis-LRMN (UMR CNRS 5220, Inserm U630), Bron, France; 2Inserm U842, Bron, France

The interpretation of USPIO-induced MR signal changes at the early stages of focal cerebral ischemia remains controversial. Cerebral infarctions were induced in 40 mice using permanent middle cerebral artery occlusion (pMCAO) by electrocoagulation. Ferumoxtran-10 USPIO (Guerbet, France) were injected i.v. 5h post-injury. On gradient echo T1- weighted imaging, four areas of signal changes after USPIO injection were observed at 6 and 24h post ischemia. On histology, iron staining was mostly associated to the vascular and the cerebrospinal fluid compartments. These results strongly suggest that we must consider time-window dependent results interpretation of USPIO-related signal changes in experimental stroke models.

Novel Molecular & Cellular Imaging Agents Hall D Tuesday 13:30-15:30

1658. Single Polyplex Based Image-Guided Combined SiRNA and Enzyme/Prodrug Cancer Therapy Cong Li1, Paul Winnard Jr1, Tomoyo Takagi1, Dmitri Artemov1, Zaver M. Bhujwalla1 1Johns Hopkins Univ., Baltimore, Maryland, USA

We have previously demonstrated the feasibility of performing image-guided prodrug enzyme therapy by incorporating MR and optical reporters on a prototype agent containing bacterial cytosine deaminase (CD), the enzyme that converts a non-toxic prodrug 5-fluorocytosine (5-FC) to 5-fluorouracil (5-FU). In a separate study we observed that siRNA-mediated downregulation of choline kinase increased the cell kill effects of 5-FU in breast cancer cells, but not nonmalignant breast cells. Here we are developing a strategy to incorporate siRNA within this prototype agent to generate 5-FU through conversion by CD within the tumor together with downregulation of choline kinase

1659. Bacterial Gene Provides Cellular Contrast for MRI Donna Elizabeth Goldhawk1, Claude Lemaire2, Savita Dhanvantari1, R. Terry Thompson1, Frank S. Prato1 1LHRI, London, Canada; 2University of Waterloo, Waterloo, Canada

Magnetotactic bacteria derive their magnetic properties from magnetosomes: membrane-bound, intracellular structures that form iron biominerals in response to the coordinated activity of approximately 20 genes. Similar to SPIO particles in size and composition, magnetosomes respond comparably to magnetic fields. We have investigated the ability of mammalian cells to produce magnetosome-like particles by expressing one of the bacterial genes: MagA, which encodes a putative iron transporter. High field MRI demonstrated that overexpression of GFP-MagA fusion protein increases cellular contrast in mouse neuroblastoma cells. These findings suggest that reporter gene expression systems for molecular MRI may be developed using magnetosome-related genes.

1660. A Gene Reporter System for Detection of Cellular LacZ Expression by Magnetic Resonance Imaging Niclas Emanuel Bengtsson1, Glenn A. Walter1, Edward W. Scott1 1University of Florida, Gainesville, Florida, USA

The commercially available substrate S-gal reacts with â-galactosidase to produce a dark iron-rich precipitate that can be used as a genetic reporter system for simultaneous detection by MRI and histology. We found that S-gal labeling reduced T2* relaxation time for â-gal expressing bone marrow cells (BMCs) significantly more than control cells and the change in T2* increased dramatically with increasing magnetic field strengths. This decrease in T2* relaxation time translated into increased sensitivity and detection capabilities of transplanted â-Gal+ BMCs in vivo at 11.1T compared to 4.7T.

Poster Sessions

285

1661. Nanoprobes for 1H MRI Based Oximetry Vikram D. Kodibagkar1, Xianghui Wang, Praveen Gulaka, Ralph P. Mason2 1UT Southwestern Medical Center at Dallas, Dallas , USA; 2UT Southwestern Medical Center at Dallas, Dallas, USA

There is increasing evidence for the importance of tissue oxygenation in development, progression, and response to cancer therapy. We present here synthesis, characterization and application of HMDSO based nanoemulsions suitable for intravenous delivery for 1H MR oximetry applications. The nanoprobes were prepared by ultrasonic emulsification of a mixture of HMDSO, Solutol® as surfactant and de-ionised water. Samples were bubbled with different oxygen mixtures and R1 (=1/T1) was measured as a function of pO2. The calibration curve for HMDSO based nanoprobes matched that of neat HMDSO. The nanoprobes show promise for in vivo measurements of pO2 and studies are currently underway.

1662. Carbon Coated Microshells Containing Nanosized Gd(III)-Oxidic Phases for Multiple Bio-Medical Applications Eliana Gianolio1, Aldo Arrais2, Stefano Avedano2, Giovanni Battista Giovenzana3, Enrico Boccaleri2, Mauro Botta2, Pier Luigi Staghellini2, Silvio Aime1 1Università di Torino, Torino, Italy; 2Università del Piemonte Orientale A. Avogadro, Alessandria, Italy; 3Università del Piemonte Orientale A. Avogadro, Novara, Italy

Herein is reported the high-yield synthesis and characterization of microsized graphenic carbon shells embedding nanometric Gd(III) oxidic phase to be applied as T2-susceptibility agents in MRI, X-ray scattering material in CT and activable substrates for Neutron Capture Therapy. The materials have been simply achieved by thermal treatment of raw humic acid precursor and GdCl3. They have been characterized by mean of multiple FT-IR and Raman, TGA, XRPD, XPS, SEM-EDAX and TEM techniques. The obtained capsular systems are featured with enhanced thermal and chemical stability and inherteness.

1663. Towards Powerful T1 and T2 MRI Contrast Agents: Noncovalent Functionalization of Carbon Nanotubes with Amphiphilic Gd3+ Chelates Cyrille Richard1, Bich-Thuy Doan2, Jean-Claude Beloeil3, Michel Bessodes4, Eva Toth3, Daniel Scherman1 1CNRS, Paris, France; 2CNRS, Gif sur Yvette, France; 3CNRS, Orléans, France; 4INSERM, Paris, France

A new T1 and T2 contrast agent has been developed, based on an amphiphilic gadolinium chelate adsorbed on multiwalled carbon nanotubes. The stable suspensions have been characterized with regard to MRI contrast agent applications. Relaxivities, r1, (20, 300 and 500 MHz) show a strong dependence on the GdL concentration, particularly at low field. Relaxation times T2 are practically independent of both the frequency and the GdL concentration. An in vivo feasibility MRI study performed at 300 MHz in mice revealed a negative contrast after injection of a suspension of functionalized nanotubes into the leg muscle.

1664. In Vitro Relaxivities Studies of Gadolinium Carbon Nanotubes at 0.2T Kelvin Wong1, Jeyarama S. Ananta2, Samuel Patz3, Iga Muradyan3, Lon J. Wilson2 1The Methodist Hospital Research Institute, Houston, USA; 2Rice University, Houston, USA; 3Brigham and Women's Hospital, Boston, Massachusetts, USA

In this study, we characterize the r1 and r2 relaxivities of Gadonanotubes with different surfactant coatings at 0.2T using phantom imaging. The r1 relaxivity of bundled and individual Gadonanotubes were around 380 and dextran-coated Gadonanotubes has a high r1 at 800 mM-1s-1. All Gadonanotubes we tested have higher r1 relaxivities than previously reported NMRD studies. The r2 relaxivities of all Gadonanotubes are similar in the range of 300 mM-1s-

1. Gadonanotubes is a strong positive MR contrast agents at 0.2T.

1665. In Vitro Relaxivities Studies of Gadolinium Carbon Nanotubes at 3T Kelvin Wong1, Jeyarama S. Ananta2, Stephen Lin1, Lon J. Wilson2 1The Methodist Hospital Research Institute, Houston, USA; 2Rice University, Houston, USA

Gadolinium loaded ultra-short single wall carbon nanotubes have been recently proposed to be a high r1 relaxivity superparamagnetic MR contrast agent. Three Gadonanotube samples with different surfactant coatings were prepared and used in an in vitro phantom study. They were compared to two other contrast agents, a commercial gadolinium chelate and monocrystalline iron-oxide (MION). Our results show that bundled Gadonanotubes have at least three times higher r2* relaxivity compared to individual Gadonanotubes and about ten times higher r2* relaxivity than MION, indicating that Gadonanotubes may be a promising agent for in vivo cell labeling MRI.

1666. MRI Observation of the Light-Induced Release of Contrast Agent from Photo-Controllable Polymer Micelles Martin Lepage1, Jinqiang Jiang1, Jérôme Babin1, Bo Qi1, Luc Tremblay1, Yue Zhao1 1Université de Sherbrooke, Sherbrooke, Canada

A contrast agent was encapsulated into a photo-controllable nanocarrier and subsequently released upon absorption of UV light. We describe an in vitro MRI assay that can evaluate the state of incorporation of a small Gd-based contrast agent.

1667. A Novel Solubility-Switchable MRI Agent Allows the Non-Invasive Detection of Matrix Metalloproteinase-2 Activity in Vivo in a Mouse Model Réjean Lebel1, Beata Jastrzebska1, Hélène Therriault1, Marie-Michèle Cournoyer1, J Oliver McIntyre2, Emanuel Escher, Witold Neugebauer, Benoit Paquette1, Martin Lepage1 1Faculté de médecine, Université de Sherbrooke, Sherbrooke, Canada; 2Vanderbilt University Medical Center, Nashville, Tennessee, USA

A novel MRI protease-modulated contrast agent (PCA) was developed to detect the activity of matrix metalloproteinase-2 (MMP-2) in vivo. The PCA incorporates a solubility switch : upon cleavage by MMP-2, it becomes hydrophobic (PCA2-switch). This leads to an accumulation of PCA2-switch in an MMP-2-positive, MC7-L1 mammary carcinoma tumor in a Balb/c mouse model compared to a MC7-L1 MMP-2-knockdown tumor. When a scrambled peptide sequence is inserted into the PCA (PCA2-scrambled), the in vitro cleavage efficiency by MMP-2 is reduced and no accumulation is detected in vivo. In conclusion, PCA2-switch specifically accumulates in MMP-2-positive tumors.

Poster Sessions

286

1668. A New Bioactivated MRI Contrast Agent : Synthesis, Characterization and MR Imaging Studies Yun-Ming Wang1, Yu-Zheng Su1, Tian-Lu Cheng1, Yu-Tong Kuo2, Twei-Shiun Jaw2, Gin-Chung Liu2 1Kaohsiung Medical University, Kaohsiung, Taiwan; 2Kaohsiung Medical University Hospital, Kaohsiung, Taiwan

A smart contrast agent, the β -glucopyronuronate-containing gadolinium(III) complex GdL1 (L1 = 1-(2-difluoromethyl-4-(1-(4,7,10-triscarboxymethyl-(1,4,7,10-tetraazacyclodecyl))acetamido)phenyl β -D-glucopyronuronate) was synthesized and characterized. Relaxometric studies show that the T1 change percentage in the value of GdL1 decreases dramatically (51%) in the presence of β -glucuronidase β -G) and human serum albumin (HSA). A significant signal change percentage enhanced by MR images was observed for GdL1 solution in the presence of β -G and HSA. The MR images also shows high intensity enhancement in CT26(+β -G) with β-G gene expression but not for the CT26 β -G) without β -G gene expression.

1669. Polymersomes: A New Tool in the Armoury of CEST Agents Silvio Aime1, Daniela Delli Castelli1, Nicoletta Minari2, Alberto Sanino1, Enzo Terreno1 1University of Turin, Torino, Italy; 2University of Turin, T, Italy

The purpose of this work is to test the potential of polymersomes as novel platform for paramagnetic MRI-CEST agents. Liposomes loaded with paramagnetic shift reagents have been already proposed for this scope, but for in vivo applications it is necessary to improve the stability of the nanovesicles that are quite avidly taken up by macrophages. It has been reported that polymersomes display a higher in vivo stability than liposomes. The main result of this work is that the CEST properties of polymersomes are very similar to liposomes, thus making the former promising candidates for in vivo detection of CEST contrast.

1670. Novel Type of 19F MRI Contrast Agent Stefanie Cordula Sparka1, Anne Werner1, Thomas Kampf1, Thomas Christian Basse-Lüsebrink2, Daniel Haddad2, Wolfgang Rudolf Bauer3, Peter Michael Jakob1, Wolfdieter A. Schenk1 1Universität Würzburg, Würzburg, Germany; 2Research Center Magnetic Resonance Bavaria, Würzburg, Germany; 3Universtätsklinikum Würzburg, Würzburg, Germany

A new type of 19F MRI contrast agent based on NH2-1B-DTPA were synthesized. Furthermore, MR-experiments were performed to analyze and visualize the different multi resonant 19F contrast agents.

1671. Synthesis of a Blood Brain Barrier (BBB)-Permeable MR Imaging Probe Mohanraja Kumar1, Zdravka Medarova1, Guangping Dai1, Anna Moore1 1Massachusetts General Hospital, Charlestown, USA

The discovery of novel carriers capable of transporting imaging or therapeutic agents across the blood brain barrier is an important goal of neurological research. Here we report on a synthesis of a Gd-labeled fatty acylated polyarginine peptides (MPAP-Gd) with unique membrane translocation capacity. It was tested in mice injected intravenously MPAP-Gd. On T1 weighted images, there was a distinctive enhancement of the ventricles after injection of MPAP-Gd. Quantitative T1 map analysis revealed a marked shortening of the brain T1 immediately after injection. The ICP analysis of brain homogenates revealed an increase Gd content compared to mice injected with Gd-DOTA.

1672. Functionalizing Poly(Ethyleneimine) DNA Carriers with Gd-DOTA Contrast Alexander B. Pine1, 2, Min Suk Shim2, Young Kwon2 1Cleveland Clinic, Cleveland, Ohio, USA; 2Case Western Reserve University, Cleveland, Ohio, USA

Recently we developed a method for functionalizing the polymeric gene carrier with an MRI contrastagent. Our technology involves DNA-encapsulating poly(ethyleneimine) (PEI) nanoparticles, which were fabricated in such a way that a controlled amount of MRI contrast agent, Gd-DOTA, was conjugated with primary amine terminals of PEI, which were subsequently condensed into DNA/PEI polyplexes. The presence of chelated paramagnetic gadolinium ions made the nanoparticles amenable to noninvasive detection using MRI, thus enabling a new approach to studying trafficking, biodistribution and localization ofthe polyplexes.

Cell Labelling Applications Hall D Wednesday 13:30-15:30

1673. Measuring Dendritic Cell Migration to Lymph Nodes Jonatan Ashchar Snir1, Greg A. Dekaban2, Peta O’Connell2, Paula J. Foster1 1Robarts Research Institute, London, Canada; 2Robarts research Institute, London, Canada

The immune system plays an important role in preventing cancer. Dendritic Cells (DC) are considered effective therapeutic candidates for treatment of cancer; however, many fundamental questions about how to best prepare and administer them are unanswered. At present, it is not possible to quantitate the delivery and migration of DC-based vaccines without biopsy or excision of the lymphoid tissue. Our study shows that DC can be labeled with Feridex and imaged using a 1.5T GE MR scanner. Further, the lymph node volume, signal void volume and fractional signal loss measured correlate with the delivery and migration of in vitro-generated DC.

1674. Magnetically Labeled Neural Stem Cells Exhibit Differential Gene Expression of Zinc (Finger) Binding Proteins Dorota Anna Kedziorek1, Piotr Walczak1, Chunfa C. Jie1, Naser Muja1, Jesus Ruiz-Cabello2, Assaf A. Gilad1, Jeff W.M. Bulte1 1Johns Hopkins University, Baltimore, USA; 2Universidad Complutense de Madrid, Madrid, Spain

We assessed the time-dependent changes in gene expression following labeling of neural stem cells with Feridex and poly-L-lysine.A pronounced difference in the time course of the expression of zinc (finger) binding proteins was found. These specific regulatory proteins are responsible for maintaining cellular homeostasis indirectly through DNA and RNA binding interference. Our results are relevant for further clinical implementation of MRI cell tracking.

Poster Sessions

287

1675. Developing Cellular MPI: Initial Experience Jeff W. M. Bulte1, 2, Bernhard Gleich3, Jurgen Weizenecker3, Segun Bernard1, Piotr Walczak1, Dennis E. Markov4, Hans C. J. Aerts5, Jorgen Borgert3, Hans Boeve4 1The Johns Hopkins University School of Medicine, Baltimore, USA; 2The Johns Hopkins University Whiting School of Engineering, Baltimore, USA; 3Philips Research Europe, Hamburg, Germany; 4Philips Research Europe, Eindhoven, Netherlands; 5Philips Medical Systems, Best, Netherlands

Using clinical formulations of SPIO particles used as MRI contrast agents, we investigated the potential of magnetic particle imaging (MPI) for quantitative stem cell tracking. We observed a linear correlation between MPI signal and iron content, representative for the total cell number over a wide range of concentrations, independent of the particle state as free or intracellular entity. Unlike in MRI, Resovist had a 4–fold higher efficacy per unit Fe than Feridex for two different stem cell types tested. MPI has potential for non-invasive quantitative cell tracking and deserves further exploration with or without the use of MRI in parallel.

1676. Non-Invasive Assessment of Chronic Cardiac Allograft Rejection in a Rat Model with in Vivo MR Imaging of Immune Cells Labeled with MPIO Particles Qing Ye1, Yijen L. Wu1, Lesley M. Foley1, T. Kevin Hitchens1, Haosen Zhang1, Haval Shirwan2, Chien Ho1 1Carnegie Mellon University, Pittsburgh, Pennsylvania, USA; 2University of Lousville, Louisville, Kentucky, USA

Chronic cardiac allograft rejection (CCAR) constitutes a major obstacle to the long-term success of heart transplantation. Studies indicate the involvement of immune cells in the development of CCAR. In this study, we used a chronic rejection working heart rat model. Immune cells (mainly macrophages) were labeled in situ with micrometer-sized paramagnetic iron oxide (MPIO) particles, and their accumulation in the rejecting allograft was monitored non-invasively with MRI. Our data showed that the distribution of macrophage can be non-invasively assessed using in vivo MRI, and the MRI results were well correlated with ex vivo MR microscopy and the pathology changes.

1677. Does Prussian Blue Staining Correlate with Dextran Staining of Ferumoxides Labeled Cells? Aneeka Chaudhry1, Joseph A. Frank1, Edyta Pawelczyk1 1National Institutes of Health, Bethesda, USA

Dextran coated iron oxide nanoparticles (SPION) are used to magnetically label cells for cellular MRI. Prussian blue (PB) and/or dextran staining has been used to identify SPION labeled cells in tissue on histology. However, no comparisons have been made on the detection efficiency of SPION in cells. Ferumoxides (FE) labeled cells were followed over 14 days for dextran positive cells compared to PB + cells and iron content. Results demonstrated that there was greater percentage of PB +cells compared to dextran positive cells at 7 and 14 days post FE labeling.

1678. MRI of Neural Stem Cell Migration in the Adult Mouse Brain Jeffrey You Ling Shyu1, Brian J. Nieman1, Daniel H. Turnbull1 1New York University School of Medicine, New York, New York, USA

Iron-oxide particles, a favored agent for cellular MRI, can be used to label endogenous neural stem cells (NSCs) in situ in rodents. Previous studies required the injection of large numbers of micron-sized particles of iron oxide (MPIOs), creating a large hypointensity artifact that restricts the study of NSC response to injury. In this work, MPIOs were injected directly into the subventricular zone of the adult mouse brain; a much smaller volume of iron-oxide particles was needed to observe migration along the rostral migratory stream. This method may greatly aid the study of endogenous NSC responses to brain injury and disease.

1679. Quantitative Cellular Tracking MRI of Human Mesenchymal Stem Cells Home to the Metastatic Breast Cancer in the Rat Brain Ho-Taek Song1, 2, Elain K. Jordan1, Bobbi K. Lewis1, Jae-Hyun Lee, Young-wook Jun, Jinwoo Choen, Joseph A. Frank1 1Clinical Center, National Institite of Health, Bethesda, USA; 2College of Medicine, Yonsei University, Seoul, Republic of Korea

In this study we demonstrate that the MR T2* map histogram can be used to monitor the homing of magnetically labeled human mesenchymal stem cells (hMSCs) to sites of metastatic breast cancer in rat brains at 3T. hMSCs were labeled with ferumoxides-protamine sulfate, micron sized iron oxide particles and engineered manganese iron oxide nanoparticles. Quantitative T2* maps revealed no difference among the labeled MSC to home to sites of brain metastatsis as confirmed by immunohistochemical stainning for MSCs<

1680. In Vivo Serial Monitoring of Implanted Chemically Biotinylated Cells by MRI Po-Wah So1, Tammy Kalber1, Jimmy D. Bell1 1Hammersmith Hospital, Imperial College London, London, UK

In vivo monitoring of specific cell populations is essential for the development of cell based therapies. Recently, chemical biotinylation of cells and their subsequent ‘tagging’ by antibodies to biotin conjugated to SPIOs has been proposed as a ready and rapid method of labeling cells for MRI tracking in vivo. In this study we have demonstrated the feasibility of cells labeled in this manner for serial MRI monitoring over a period of 3 days after implantation.

1681. Direct Incubation of PBMCs with Ferumoxides Labels Monocytes and B Cells John S. Pratt1, Anna Moore1, Alma Gregory Sorensen1 1Massachusetts General Hospital, Charlestown, Massachusetts, USA

The purpose of this study was determine the feasibility of labeling peripheral blood mononuclear cells (PBMCs) by direct incubation with ferumoxides, and to evaluate the types of leukocytes labeled by this method for the eventual development of MRI-based clinical monitoring of leukocytes in patients. Human peripheral blood mononuclear cells are readily labeled by direct incubation with clinically approved ferumoxides. Labeling was sufficient for detection of cells by 4.7T MRI. Detailed analysis of the cell types labeled revealed B cells were primary lymphocytes labeled. Application of this methodology may contribute new knowledge to the poorly understood role of B cells in leukemia and other diseases, and further clinical translation of MRI-based cellular imaging.

Poster Sessions

288

1682. Quantification of Magnetically Labeled Cells with an SPIO Labeled Tumor Model in Rats wei liu1, E Kay Jordan2, Hannes Dahnke3, Joseph A. Frank2 1Philips Research North America, Briarcliff Manor, New York, USA; 2National Institutes of Health, Bethesda, Maryland, USA; 3Philips Research Europe, Hamburg, Germany

Quantifying the number of labeled stem cells in target tissues in experimental models is of great importance to optimize dose and timing of cellular therapy. In this study, we investigated the quantitative relationship between labeled cells and tumor R2* relaxation rate at different stages of the tumor development with an SPIO labeled tumor model in rats. The individual linear relationship from each tumor was consistent with the gross linear correlation between tumor R2* and number of SPIO labeled cells/mm3. The detection limit for SPIO labeled tumor cells was estimated at about 316 cells/mm3 in this model.

1683. Tracking Magnetotactic Bacteria Using an MRI System for Future In-Vivo Therapeutic Targeting Ouajdi Felfoul1, Sylvain Martel1 1École Polytechnique de Montréal (EPM), Montreal, Canada

Magnetotactic bacteria (MTB) are flagellated microorganisms that can be controlled using an external magnetic field. MTB synthesize intracellular magnetite nanoparticles, called magnetosomes, assembled in a chain acting as a compass to influence through magnetotaxis the swimming direction of the bacteria. The magnetosomes that disturb the local magnetic field could allow MTB tracking deep in the human body using an MRI system. MR-images of MTB are studied in order to validate the possibility of tracking MTB-based drug delivery operations using a clinical MR scanner. MTB affect more the T2 than the T1-relaxation rate and can be though as a negative contrast agent.

1684. Superparamagnetic Iron Oxide and Protamine Sulfate Do Not Affect the Viability and Multi-Transdifferentiation Capacity of Adult Stem Cells Jixian Deng1, Bo Xiang1, Tonghua Yang1, Lei Wang1, Gang Li1, Jian Wang1, Tarek Kashour1, Alan Menkis2, Boguslaw Tomanek1, Roxanne Deslauriers1, Rakesh Arora2, Ganghong Tian1 1National Research Council Canada, Winnipeg, Canada; 2St. Boniface General Hospital, Winnipeg, Canada

This study was designed to assess the effects of superparamagnetic iron oxide (SPIO) and protamine sulfate (PS) on the viability and multi-transdifferentiation capacity of adult stem cells. To achieve the objective, adipose-derived stem cells (ADSCs) were cultured in a medium containing different concentrations of SPIO and PS. Then, the ADSCs were subjected to three types of transdifferentiation inductions (adipogenic, osteogenic, and myogenic induction). We found that SPIO and PS did not affect the viability and multipotent transdifferentiation capacity of the ADSCs. We therefore conclude that SPIO is a safe MR contrast reagent for in vivo tracking of the adult stem cells and PS is a safe SPIO-loading reagent.

1685. USPIO-Enhanced MR Imaging of Macrophage Recruitment Into the Rat Brain Following MCP-1 Microinjection Andrew Peter Brown1, 2, Irene Tracey1, Daniel C. Anthony1, Sebastien Serres1, Yanyan Jiang1, Nicola R. Sibson1 1University of Oxford, Oxford, UK; 2Glaxosmithkline, Hammersmith Hospital, UK

USPIOs can be visualised as a distinct reduction in signal intensity on T2* weighted MR images and can provide a method of tracking macrophage recruitment to sites of neuroinflammation. There are issues regarding the distinction between iron-laden recruited macrophages and the entry of free iron across a permeable blood brain barrier (BBB) in disease cases. In the current study we have shown that USPIO-enhanced MRI can provide a technique to determine the relationship between the number of recruited macrophages to an area of CNS tissue damage and signal change following microinjection of MCP-1 into the rodent striatum.

1686. Biocompatible Chitosan Nanoparticles Encapsulating Iron Oxide with a MRI High-Relaxivity Hsiao-Yun Kuo1, 2, Jiun-Jie Wang, Rei-Tsan Tsai, I-Ru Chang1, KoonKuan Ng, Chao-Lin Liu3, Chia-Rui Shen1 1Chang Gung University, Kweishan, Taiwan; 2 Chang Gung Memorial Hospital, Kweishan, Taiwan; 3Min Chi University of Technology, Taishan, Taiwan

Chitosan encapsulating superparamagnetic iron oxide maintains the desirable high relaxivity and less cytotoxicity

1687. T1 and T2 Quantification of Free USPIO and USPIO-Labeled Macrophages at 4.7T and 7T Jean-Christophe Brisset1, Virginie Desestret1, Sebastien Marcellino2, Emilie Devillard1, Florence Lagarde2, Norbert Nighoghossian1, Yves Berthezene1, Marlene Wiart1 1Université de lyon, CREATIS-LRMN, UMR CNRS 5220, Inserm U630, Lyon, France; 2Université de lyon, Laboratoire des Sciences Analytiques, UMR 5180 CNRS-UCBL, Lyon, France

USPIO-enhanced MRI is a promising tool for the experimental study of inflammation. The aim of this study was to quantify the effects of compartmentalization of USPIO on T1 and T2 relaxivities at 4.7T and 7T, using phantoms of free USPIO versus USPIO-labeled macrophages. Compartmentalization of USPIO resulted in a decrease of T1 and T2 effects of the iron particles. T1 and T2 relaxivities of USPIO-labeled cells were lower at 7T than at 4.7T. Taken together, these results suggest that working at 4.7T may be a good compromise between sufficient spatial resolution achievable to image small animals and USPIO relaxivity properties

1688. 19F MRI Detection of Acute Cardiac Allograft Rejection with in Situ Perfluorocarbon Labeling of Immune Cells T Kevin Hitchens1, 2, Qing Ye1, Haosen Zhang1, Lesley M. Foley1, Jelena M. Janjic1, Eric T. Ahrens1, Chien Ho1 1Carnegie Mellon University, Pittsburgh, Pennsylvania, USA

The gold standard for diagnosing and staging rejection after organ transplantation is biopsy, which is not only invasive but also prone to sampling errors. Cellular imaging of the immune cell accumulation in the rejecting graft may provide a better approach. We present a method to detect rejection in a rodent cardiac transplantation model via in situ labeling of immune cells with a perfluorocarbon nanoemulsion. The accumulation of 19F labeled cells can be located and quantified, unambiguously, by 19F MRI, then the labeled cells can then be placed in their correct anatomical context with a conventional 1H image.

Poster Sessions

289

1689. Manganese Guided Cellular Magnetic Resonance Imaging Enables Evaluation of Human Stromal Cell Viability Mayumi Yamada1, Paul T. Gurney1, William Stein1, Pratima Kundu1, Alan Smith2, Robert C. Robbins1, Phillip C. Yang1 1Stanford University, Stanford, California , USA; 2Cognate Bio Services, Inc., Sunnyvale, California , USA

Manganese chloride can demonstrate the potential to detect cellular viability and biological property and it can be used for non invasive biological evaluation of transplanted human stromal stem cells within injured myocardium.

1690. In Vivo Mitochondrial Labeling Using Mito-Carboxy Proxyl (Mito-CP) Enhanced Magnetic Resonance Imaging Douglas Edward Prah1, Eric S. Paulson1, Melissa Lynn Wagner-Schuman1, J Zielonka1, Marcos Lopez1, Miguel J. Hardy1, Joy Joseph1, B Kalyanaraman1, Kathleen M. Schmainda1 1Medical College of Wisconsin, Milwaukee, Wisconsin, USA

Due to their single unpaired electron, nitroxides could potentially be used as MR contrast agents. Recent evidence suggests that the nitroxide, Mito-Carboxy Proxyl (Mito-CP), preferentially targets mitochondria. MR contrast agents specific to mitochondria would provide another avenue to study mitochondrial diseases or pathologies that exhibit abnormal metabolic and/or mitotic activity (e.g., tumors). We demonstrate here, in an in vivo study, the uptake of Mito-CP into rat breast tumor.

1691. SPIO Labeled Cells: Magnetic Resonance Source Quantification by Inverting the Dipole Field Ludovic de Rochefort1, Maire Poirier-Quinot2, Bryan Kressler1, Claire Wilhelm3, Florence Gazeau3, Jean-Christophe Ginefri2, Luc Darrasse2, Yi Wang1 1Weill Medical College of Cornell University, New York, New York, USA; 2Unité de Recherche en Résonance Magnétique Médicale, U2R2M, Université Paris-Sud, CNRS UMR8081, Le Kremlin-Bicêtre, France; 3Laboratoire Matières et Systèmes complexes, Université Paris 7, CNRS UMR7057, Paris, France

The local dipole field resulting from the strong magnetic moment surrounding superparamegnetic iron oxides creates signal voids (T2* effects) very well observed with gradient-echo imaging. Here, we propose the MR-SQUID technique which combines field mapping and data processing to allow quantification of the magnetic source causing the field shifts. This quantitative 'positive contrast' technique is applied on SPIO-loaded cells. Measured mass of iron per cell agrees with calibrated quantities down to the pg level.

1692. In Vitro / in Vivo MRI Visualization of PFC / VSOP Double-Labeled Mesenchymal Stem Cells Thomas Kampf1, Thomas Christian Basse-Luesebrink2, Meike Weber1, Andrea Heymer1, Regina Ebert1, Christian Stoetzel1, Uwe Gbureck1, Ulrich Noeth1, Peter Michael Jakob1, Wolfgang Rudolf Bauer3, Daniel Haddad2 1University of Wuerzburg, Wuerzburg, Germany; 2Research Center Magnetic Resonance Bavaria, Wuerzburg, Germany; 3Universtity of Wuerzburg, Wuerzburg, Germany

In this work we introduce an new double lable scheme for non ambigouse monitoring of iron oxide labeled cells. The superparamagnetic iron oxide particles can be used as MRI markers in high resolution T2* weighted 1H-MR images. To distinguish the iron oxide labeled cells from other hypointensities in the MR image cells are additionally labeled with PF15C nanoparticles. In lower resolved 19F-MR images the position of the double labeled cells can be verified.

1693. Rat Glioma C6 Cells Labeled with a Fluorinated Gd-GlyMe-DOTA-Complex Markus Plaumann1, Jan Willmann1, Ekkehard Küstermann1, Uwe Schüssler1, Dieter Leibfritz1 1University of Bremen, Bremen, Germany

Fluorine is of interest in medical chemistry and diagnostics, because of its very low natural abundance in living organisms and high MR sensitivity. Fluorinated contrast agents allow to record 19F-images without any background signals. Six different 3,5-Bis(trifluoromethyl)benzyl derivatives were selected as model compounds to compare Gd-DTPA- and Gd-GlyMe-DOTA-complexes with respect to their T1-times. Furthermore the lipophilic properties of these Gd-complexes and also of different M3+ ions complexes of 3,5-Bis(trifluoromethyl)phenylhydrazine-DTPA, -GlyMeDOTA and -GlyMeAsp-DOTA were determined. MRI experiments and ICP-MS measurements proof the possibility to label rat glioma C6 cells with 3,5-Bis(trifluoromethyl)phenylhydrazine-Gd-GlyMeDOTA.

1694. Magnetic Resonance Imaging to Potentially Monitor Migration of Magnetically Labeled Mesenchymal Stem Cells in a Murine Model of Myocardial Infarction Yidong Yang1, 2, Ben Waghorn1, 2, Yuhui Yang1, Brianna Klein1, Nathan Yanasak1, William David Hill1, Tom C-C. Hu1, 2 1Medical College of Georgia, Augusta, Georgia, USA; 2Georgia Institute of Technology, Atlanta, Georgia, USA

MRI could serve as a powerful tool to clarify the role of mesenchymal stem cells (MSCs) in myocardial injury and the subsequent recovery process. In this study, MSCs were labeled in vitro with micrometer-sized particles of iron oxide (MPIOs) with an efficiency of 98% plus and introduced to mice via transplantation. Region of attenuated signal and dark spots in MRI were observed in the myocardial infarction site. Further work to quantify the trafficking of MSCs is needed.

Multi-Modality Contrast Agents Hall D Thursday 13:30-15:30

1695. Characterization of Graphite/metal Core-Shell Nanocrystals as Multi-Modality Contrast Agents for Macrophage and Atherosclerosis Imaging Hisanori Kosuge1, Masahiro Terashima1, Sarah Sherlock, Jin Hyung Lee, Hongjie Dai, Michael V. McConnell 1Stanford University, Stanford, California , USA

The novel graphite/metal core-shell nanocrystals (CN) are effectively taken up by macrophages in vitro and in vivo. This particles show promising properties as MRI contrast agents for noninvasive evaluation of atherosclerosis.

Poster Sessions

290

1696. A Novel Redox-Responsive, Dual-Modality MRI/optical Imaging Probe Chuqiao (Tom) Tu1, Ryan Ngao1, Angelique Louie1 1UC Davis, Davis, California , USA

We have developed a small molecule gadolinumm contrast agent that changes conformation in response to redox activity, thereby modulating relaxivity. The synthesized contrast agent responds to NADH at biologically relevant concentrations. Significant changes in MR image contrast are produced in response to chemical reductants and oxidants.

1697. Pharmacokinetics and Bio-Distribution of a Novel Silica-Based Multimodal Nanoparticle Matti M. van Schooneveld1, Esad Vucic2, Rolf Koole1, Yu Zhou2, Cheuk Y. Tang2, Klaas Nicolay3, Andries Meijerink1, Zahi A. Fayad2, Willem J.M. Mulder2 1Utrecht University, Utrecht, Netherlands; 2Mount Sinai School of Medicine, New York, New York, USA; 3Eindhoven University of Technology, Eindhoven, Netherlands

We investigated the pharmacokinetics and bio-distribution of a novel silica-based multimodal nanoparticle. This probe consists of a quantum dot (for fluorescence imaging) incorporated in a 35 nm silica nanoparticle, which is coated by paramagnetic (for MRI) and pegylated lipids to overcome the limited bio-applicability of silica particles. MRI, optical techniques, relaxation measurements, and ICP-MS were used to determine the blood half-life value and the tissue distribution at anatomical and cellular level. A 10-fold increase in the half-life value was observed in case the particles were lipidic coated as compared to non-coated particles (t1/2 = 17 min vs. 180 min).

1698. Kinetics of Avidin-Induced Clearance of Biotinylated Bimodal Liposomes for Improved MR Molecular Imaging Geralda A.F. van Tilborg1, Gustav J. Strijkers1, Emilie M. Pouget1, Chris P.M. Reutelingsperger2, Nico A.J.M. Sommerdijk1, Klaas Nicolay1, Willem j.m. Mulder3 1Eindhoven University of Technology, Eindhoven, Netherlands; 2University of Maastricht, Maastricht, Netherlands; 3Mount Sinai School of Medicine, New York, USA

Bimodal liposomes, carrying large amounts of gadolinium-lipids, were recently proposed as potent contrast agents for MR molecular imaging. These nanoparticles display a long circulation time, which enables massive accumulation at the targeted site but also keeps the target to background ratio low for a prolonged period. In this study an avidin chase was designed to rapidly clear paramagnetic biotinylated liposomes from the blood circulation. Avidin-induced alterations in the biodistribution and blood clearance kinetics were studied. The ability to rapidly clear circulating contrast agent opens up exciting possibilities to study targeting kinetics and to optimize nano-particulate contrast agent formulations.

1699. In Vivo T1 and T2 Effects of Paramagnetic Quantum Dot Based Contrast Agents for Molecular Magnetic Resonance Imaging Marlies Oostendorp1, 2, Kim Douma2, Tilman M. Hackeng2, Anouk Dirksen2, Mark J. Post2, Marc A.M.J. van Zandvoort2, Walter H. Backes1, 2 1Maastricht University Hospital, Maastricht, Netherlands; 2Maastricht University, Maastricht, Netherlands

Paramagnetic quantum dots (pQD), Gadolinium-loaded fluorescent semiconductor nanoparticles, are becoming more popular as molecular MRI contrast agent. Besides decreasing the local T1 relaxation time, it is expected that the semiconductive properties of pQD result in field inhomogeneities, which contribute to T2 relaxation time shortening. It is therefore unknown whether T1 or T2 based methods show the strongest contrast enhancement upon pQD injection. Here, we applied a quantitative molecular MRI method to analyze tissue T1 and T2 and the changes thereof induced by pQD targeted to the angiogenic tumor vasculature. Significant differences were only found for T1 based effects.

1700. MR and Optical Target Imaging for Intracranial Tumors with Chlorotoxin Conjugated Nanoprobes Donghoon Lee1, Conroy Sun1, Omid Veiseh1, Chen Fang1, Stacey Hansen2, Miqin Zhang1, James Olson2, Richard Ellenbogen1 1University of Washington, Seattle, Washington, USA; 2Fred Hutchinson Cancer Research Center, Seattle, Washington, USA

Nanoprobes were developed for MR and optical target imaging of intracranial tumors. Currently, nanoconjugates have been limited in target imaging for intracranial tumors due to insufficient accumulation within tumor and inability to cross the blood brain barrier (BBB). Our developed nanoconjugates were iron oxide nanoparticles coated with PEG (polyethylene glycol)-chitosan conjugated with chlorotoxin. Images acquired by MR and optical imaging revealed specific particle uptakes by intracranial tumors for 2-5 days post injections and evidence of the nanoprobes passing through the BBB for mouse model with BBB intact. Histology data also supported the results.

1701. Multimodal Imaging of Luciferase Transgenic Dendritic Cells Using Magnetic Resonance Imaging (MRI) Based Tracking After Allogeneic Hematopoietic Cell Transplantation Wilfried Reichardt1, Robert Zeiser2, Jürgen Hennig1, Dominik von Elverfeldt1 1University of Freiburg, Freiburg, Germany; 2Stanford University School of Medicine, Stanford, USA

Synopsis:Insight into the trafficking pattern of dendritic cell (DC) populations into lymphoid and non-lymphoid tissues after allogeneic hematopoietic cell transplantation (aHCT) is critical to understand the complex processes that regulate graft-versus-host disease. We were able to generate a platform for in vivo bioluminescence (BLI) and magnetic resonance imaging (MRI) based cell trafficking studies by labelling luciferase transgenic DC with superparamagnetic iron oxide (SPIO) Nano particles bound to a murine IgG antibody.

Poster Sessions

291

1702. Dual Modality Imaging of Phosphatidylcholine-Specific Phospholipase C in DU145 Prostate Cancer Cells and Solid Tumors Theresa Meganne Mawn1, Daniel-Joseph Leung1, Nancy Beardsley1, Anitoliy Popov1, E. James Delikatny1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA

We have employed a dual modality approach to detect changes in lipid metabolites and phosphatidylcholine-specific phospholipase C (PC-PLC) activity in prostate cancer cells and solid tumors. MRS studies have consistently revealed the presence of elevated levels of phosphocholine (PCho) in various types of cancer. However, it remains uncertain whether these elevations are due to choline transport and choline kinase, or occur catabolically through the action of PC-PLC. By combining MRS with a near-infrared (NIR) PC-PLC-activated optical imaging probe, we are able to directly image the relative contributions of the anabolic and catabolic pathways to PCho elevations in cancer.

1703. Molecular NMR and EPR in Vivo Detection of Inflammation Using Specific E-Selectin Targeted Iron Oxides Kim Anne Radermacher1, Nelson Beghein1, Sebastien Boutry2, Sophie Laurent2, Luce Vander Elst2, Robert N. Muller2, Benedicte F. Jordan1, Bernard Gallez1 1Université Catholique de Louvain, Brussels, Belgium; 2University of Mons-Hainaut, Mons, Belgium

The aim of the study was to develop a molecular marker for non invasive diagnosis and monitoring in the early stages of inflammation. An E-selectin ligand was coupled to ultrasmall particles of iron oxide (USPIO). After intravenous injection of the grafted or ungrafted USPIO, their concentration was evaluated in inflamed muscle ex vivo by an EPR X-band and in vivo by an EPR L-band, as well as by MRI. All three methods demonstrate that the specific targeting of grafted USPIO was twice higher in inflamed tissues than using the ungrafted ones.

Perfusion & Permeability Methodology Hall D Monday 14:00-16:00

1704. Is It Possible to Measure Water Exchange Using Conventional DCE-MRI? David L. Buckley1, Lucy E. Kershaw1, Greg J. Stanisz2, 3 1University of Manchester, Manchester, UK; 2University of Toronto, Toronto, Canada; 3Sunnybrook Health Sciences Centre, Toronto, Canada

The importance of cellular-interstitial (transcytolemmal) water exchange (WX) in the measurement of contrast agent concentration using MRI is unclear. Early studies suggested that its influence could be avoided by appropriate choice of imaging sequence. More recent papers stress the importance of measuring WX (e.g. using a “shutter-speed” model). We studied human muscle and analyzed DCE-MRI data with a series of models encompassing the full range of WX scenarios. We concluded that the effect on our data was small and that conventional DCE-MRI is unsuitable for WX measurement.

1705. Impact of AIF Errors on DCE-MRI Pharmacokinetic Parameters: Comparison of a High Temporal Resolution AIF and a Biexponential Description Hai-Ling Margaret Cheng1, 2 1The Hospital for Sick Children, Toronto, Canada; 2University of Toronto, Toronto, Canada

A rapidly sampled arterial input function (AIF) is known to be essential for accurate DCE-MRI quantification. However, AIF measurement is subject to errors, particularly in the initial bolus phase, and it is unknown how these affect pharmacokinetic parameter accuracy. Simulations are performed to investigate the impact of AIF errors and to compare with a more slowly but carefully acquired biexponential AIF. Results show that a bolus amplitude error in a rapidly sampled AIF introduces significant error in the transfer constant and blood volume. When the bolus amplitude error exceeds 25%, the biexponential AIF provides more accurate parameter estimates.

1706. Sampling Frequency Dependent Identifiability of Pharmacokinetic Parameters for Small and Large Molecular Contrast Agents Karolien Jaspers1, 2, Mark J. Post2, Tim Leiner1, 2, Walter H. Backes1, 2 1Maastricht University Hospital, Maastricht, Netherlands; 2Maastricht University, Maastricht, Netherlands

The influence of the sampling rate and SNR on the identifiability of pharmacokinetic parameters, as defined in the Kety model, was investigated using Monte Carlo simulations, and the implications on designing a DCE-MRI protocol were discussed. In vivo measurements were used for construction of the arterial input function and noise level determinationThe precision and accuracy in parameter estimation at the lower frequencies was better for large molecular than for small molecular contrast agents This would allow lower sampling rates for large molecular contrast agents, and concomitant increase of spatial resolution, provided that sufficient SNR is obtained.

1707. IntraVoxel Partially Coherent Motion (IVPCM) Technique: Application on Skeletal Muscle Microvasculature Dimitrios C. Karampinos1, 2, Kevin F. King2, Bradley P. Sutton1, John G. Georgiadis1 1University of Illinois at Urbana-Champaign, Urbana, Illinois, USA; 2General Electric Healthcare, Waukesha, Wisconsin, USA

A reformulation of the IntraVoxel Incoherent Motion (IVIM) technique, based on the low b-value diffusion-weighted imaging regime, is proposed to characterize microcirculation of tissues perfused with partially coherent blood flow. The new methodology, termed IntraVoxel Partially Coherent Motion (IVPCM) technique, is suitable for tissues with oriented microvasculature and is currently applied to analyze certain geometrical parameters of the microvasculature of human calf muscle at rest. The proposed methodology has the unique capability of characterizing the anisotropy of microcirculation in vivo, in a manner analogous to the capability of high b-value diffusion to characterize the anisotropy of neural tracts.

Poster Sessions

292

1708. The Effect of Blood Inflow and B1 Inhomogeneity on the Arterial Input Function in 3-D DCE-MRI Caleb Roberts1, Ross A. Little1, Sha Zhao1, Yvonne Watson1, David L. Buckley1, Geoff J. Parker1 1The University of Manchester, Manchester, UK

An accurate individual measurement of the arterial input function (AIF) is required to achieve reliable estimates of microvascular characteristics in 3D dynamic contrast-enhanced MRI studies. Specific errors due to blood inflow and B1 inhomogeneity mean that the AIF measurement is challenging and location choice within the imaging slab is crucial. Using a combination of computer simulations, a flow phantom (including a “gold-standard” AIF), B1 mapping and clinical in vivo measurements we quantify these errors and demonstrate that accurate measurements of the AIF are achievable under certain conditions.

1709. Portal Delay Estimation from DCE-MRI Liver Tissue Data : Feasibility and Effect on Vascular Parameter Estimates Matthew R. Orton1, James A. d'Arcy1, David J. Collins1, David Atkinson2, David J. Hawkes2, Martin O. Leach1 1Institute of Cancer Research, Sutton, UK; 2Univeristy College London, London, UK

Using a fixed input function for kinetic modelling of DCE-MRI data is a simple and robust technique, and in many cases gives more repeatable estimates than using a measured input function. For DCE-MRI liver data a more complex dual input function is needed, and accurate determination of the delay between the arterial and portal components is critical for obtaining accurate vascular parameter estimates. This abstract presents a technique for estimating the portal delay using only tissue data, and assesses the impact of this approach on estimates of the arterial-portal partition term (also known as the Hepatic Portal Index).

1710. Limits of Accuracy in Assessing Vessel Permeabilities Using Permeability-Surface(PS)-Limited Two-Compartment Models Guido Correia Carreira1, Dirk Beyersdorff1, Lutz Lüdemann1 1Charité, Berlin, Germany

Aim of this work is to assess systematically possible over- and underestimation of vascular permeability, when using compartment models to fit DCE-MRI data of normal and tumor tissue in prostate. To this end, numerical diffusion simulations for several tissue models, describing the CM distribution process at the microscopic scale, are compared with a standard PS-limited (low permeability) two-compartment model. The results show a systematic underestimation of vessel permeabilty by the two compartment model of at least 3% to 7% up to 20% depending on the diffusion coefficient of tissue.

1711. The Effect of RF Field Non-Uniformity on Tracer Quantification in DCE MRI of the Pelvis at 3 T Cornelis A.T. van den Berg1, Reto Treier2, Jan G. Korporaal1, Greetje Groenendaal1, Fredy Visser1, Marco van Vulpen1, Uulke A. van der Heide1 1University Medical Center Utrecht, Utrecht, Netherlands; 2University of Zurich and ETHZ, Zurich, Switzerland

In DCE MRI of the pelvis the variable flip angle method is popular method to measure T1 changes allowing quantification of the bolus passage. In this study we investigated how flip angle deviations corrupt the tracer concentration quantification at 3 T. Using a B1 mapping method we found that RF field effects result in a highly inhomogeneous flip angle pattern. Flip angles in the prostate deviate 10 to 15%, flip angles in the right Iliac Externa can be 30 to 40 % lower. This will result in a large overestimation of the AIF tracer concentration as demonstrated by simulations and measurements.

1712. WITHDRAWN

MR Microscopy

The increasing application of pharmacokinetic models in combination with DCE-MRI makes it indispensable to analyze whether different models yield comparable results. Thus, we performed a comparison of two frequently used pharmacokinetic models developed by Tofts and Brix. The comparison based on the simulation model MMID4 combined with measured AIFs and physiological muscle tissue parameters found in literature. Both models showed a good sensitivity for changes in perfusion and plasma volume but a low sensitivity for permeability changes. It also indicated that the Tofts model is more robust for extreme values but only if a sufficiently high tissue perfusion exists. Hall D Tuesday 13:30-15:30

1713. Improved Tissue Contrast of Ex Vivo Mouse Brain Using Magnetic Resonance Microscopy with Different MR Contrast Agents Shuning Huang1, 2, Christina Liu2, Guangping Dai2, Young Ro Kim2, Bruce R. Rosen, 12 1MIT, Cambridge, Massachusetts, USA; 2MGH, Charlestown, Massachusetts, USA

Magnetic resonance microscopy (MRM) has been successfully used in anatomical studies of various mouse strains and transgenic/mutant mouse models. Our data now demonstrate that MR contrast agents (Gd-DTPA and MnCl2) that have different relaxation properties and tissue affinity provide different image contrast, which shows well correlation in microscopic contrast with detailed cytocarchitecture.

Poster Sessions

293

1714. Uniplanar MR Stage Microscopy: Proof-Of-Concept Imaging and Distortion Correction Lin Zhao1, Andrey V. Demyanenko1, Yun Kee1, Julian M. Tyszka1 1California Institute of Technology, Pasadena, California , USA

Initial experiences using an MR stage microscope to image millimeter scale samples are presented. An efficient model-based volumetric distortion correction scheme is also described. The stage microscope design has particular advantages for imaging relatively sensitive living samples such as developing embryos and cultured tissue explants since a much large volume of fluid medium can be used when compared to conventional volume coils with comparable sensitivity.

1715. MRI Measurements of the Morphology and Vasculature of the Mouse Eye in Vivo in Control Animals and Models of Diabetic Retinopathy Thomas Neuberger1, Sebastian Aussenhofer1, Nadine Smith1, Mary Kennett1, Thomas Gardner1, Alistair Barber1, Andrew Webb, 1, 1Penn State University, University Park, Pennsylvania, USA

To develop an in vivo model for studying ocular diseases in mouse models using MRI the morphology and the vasculature were studied in wild type as well as in retinopathy developing C57BL/6J Ins2 Akita mice. Single retinal layers were detected with nine times higher spatial resolution than achieved previously. A comparison between retinal thickness in wild type and retinopathic mice did not show statistically significant differences, unlike previous studies in rats. High resolution 3D time-of-flight measurements allowed major blood vessels of the eye in the inner retinal layer and in the outer eye to be visualized for the first time.

1716. Quantitative Magnetization Transfer Imaging for Evaluating the Tissue-Engineered Cartilage Weiguo Li1, Liu Hong1, Guoquan Zhang1, Richard Magin1 1University of Illinois at Chicago, Chicago, USA

Tissue-engineered cartilage is a promising approach for cartilage regeneration and repair. In this study, measurements of the development of tissue-engineered cartilage with quantitative magnetization transfer imaging (QMTI), T1, T2, and ADC were conducted over a 3-week growth period. These results were correlated with subsequent biochemical analysis for GAG contents. Bound proton faction (BPF) and magnetization transfer rate (k) show a statistical increase after one week in the tissue culture. This change was highly correlated with the increase of GAG. This study demonstrates that the QMTI can be used to access the changes of the ECM during engineered cartilage development.

1717. Time-Course Assessment of Pathology in a Mouse Spinal Cord Model of Multiple Sclerosis Using Ex Vivo 3D MR Microscopy Cheryl R. McCreary1, 2, Viktor Skihar1, 2, V Wee Yong1, 2, J Ross Mitchell1, 2, Jeff F. Dunn1, 2 1Unversity of Calgary, Calgary, Canada; 2University of Calgary, Calgary, Canada

Local injection of lysolecithin into the cervical spinal cord of mice provides an animal model of demyelination and remyelination. Volumes are currently assessed with serial histology, which is very time-consuming, and the results are highly variable. The aim of this study was to measure the size and extent of lysolecithin lesions using high resolution 3D gradient echo imaging of the fixed mouse spinal cord to characterize the lesion over a 4 week period.

1718. Microscopic Skin Imaging at 7T Stefan Maderwald1, 2, Oliver Kraff1, 2, Jens M. Theysohn1, 2, Marc U. Schlamann, 12, Mark E. Ladd1, 2, Harald H. Quick1, 2, Susanne C. Ladd1, 2 1Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen, Germany; 2Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen, Germany

The high SNR of 7T MRI in conjunction with a 10-cm-diameter single loop transmit/receive coil opens up new perspectives for noninvasive imaging and characterization of human skin. In-vivo MRI with high resolution (voxel volumes of 10-2mm3 and smaller) over a 10 cm FOV within short examination times are feasible and were successfully performed in ten healthy volunteers, resulting in microscopic images with excellent quality. Detailed anatomic display of normal human skin as well as birthmark lesions is provided by this imaging concept, which includes the combination of a surface TX/RX RF coil at 7T and a dedicated high-resolution imaging protocol.

1719. Perfluoropolyethers in Magnetic Resonance Microscopy: Effect on Quantitative Magnetic Resonance Imaging Measures and Histological Properties of Formalin-Fixed Brain Tissue Harpreet Hyare1, 2, Caroline Powell1, John S. Thornton1, Harry Parkes1, Laura Mancini1, Tarek Yousry1, Sebastian Brandner1, Po-Wah So2 1Institute of Neurology, London, UK; 2MRC Clinical Sciences Centre, Hammersmith Hospital, Imperial College London, London, UK

Purpose of this study was to determine whether perfluoropolyethers (PFPE) for ex vivo Magnetic Resonance Microscopy (MRM) alters MRI properties and/or the histological properties of fixed tissue. 4 of 8 formalin-fixed CD1 mouse brains were immersed into Fomblin® for 48 hours and 4 remained in 10% formol-saline as controls. After 2 days all were transferred to Fomblin® for MRI at 9.4T. No significant differences in any quantitative MR measure between the control and Fomblin-immersed mouse brains noted and no visible difference in anatomical or cellular detail noted, confirming suitability of PFPE as an embedding medium for MRM of fixed tissue.

1720. Rapid MR Microscopy of Mouse Inner Ear Structures in Vivo Using Linear Combination Steady-State Free Precession MRI H. Douglas Morris1, John A. Butman1 1National Insititutes of Health, Bethesda, Maryland, USA

MRI is an excellent method for visualizing the anatomical structures of the inner ear. Murine models of congenital deafness mutations can be quantified by microscopic MR imaging. Steady-state free precession imaging is highly selective for the endolymphatic fluid in the inner ear. Field distortions in SSFP images from nearby air filled structures can be reduced or cancelled by using a linear combination of SSFP images with different RF phase progressions. We demonstrate the utility of LCSSFP imaging in visualizing the inner ear structures of mice at 7.0T.

Poster Sessions

294

1721. Proton NMR and MRI Study of Sub-Millimeter Sized Biological Objects Seongjin Choi1, 2, Peter Christopher Hammel1, David Tay1, Petra Schmalbrock1 1Ohio State University, Columbus, USA

NMR microscopy has been used for biological research but is particularly challenging for miniature objects. Although typical NMR experiments on small seeds suffered line-broadening, oil rich seeds could be distinguished from other seeds with standard liquid NMR studies. Conventional NMR and MRI are still useful for studying seed imbibition. In our study, water-uptake in seed material in an oxygen limited environment was observed. Thus MR microscopy can be used as a complementary method to conventional seed conductivity which assesses seed quality. With further development, the current NMR microscopy system could be used for MR biopsy.

1722. Noise Characterization and SNR Benefit of Cryogenic RF Coil Xiaoli Zhang1, 2, Jun Dazai1, R Mark Henkelman1, 2 1Toronto Centre for Phenogenomics, Toronto, Canada; 2University of Toronto, Toronto, Canada

Signal-to-noise ratio is usually the major limitation to achieve higher spatial resolution in magnetic resonance microscopy such as mouse imaging. As the coil size decreases to a certain level, it becomes coil noise dominant. The purpose of this study was to understand coil and sample noise for surface coils as frequency and coil size change. A crossover point where coil noise equals sample noise at 7 T was found to be 2.1 cm in radius. SNR ratio of cryogenic coil to room temperature was predicted and compared with experimental results.

1723. Magnetic Resonance Microscopy of Blood Digestion in Ixodes Scapularis Kevin J. Hallock1 1Boston University School of Medicine, Boston, Massachusetts, USA

Hematophagous arthropods infect millions of people every year with a wide variety of diseases including Lyme disease. Lyme disease is transmitted by several ticks, but the primary vector in the northeastern United States is Ixodes scapularis. Blood feeding and digestion are essential for I. scapularis development, but few methods exist to study these processes in vivo. Here we present the first serial magnetic resonance microscopy (MRM) investigation of blood digestion in I. scapularis and report the contrast changes caused by the digestion of hemoglobin. These results demonstrate that MRM is a promising tool for studying blood digestion in ticks.

1724. Enhancement, De-Enhancement and Contrast Locking of Fixed Rodent Brains Hargun Sohi1, Daniele Procissi1, Xiaowei Zhang1, Julian Michael Tyszka1 1California Institute of Technology, Pasadena, California , USA

Contrast enhancement of fixed rodent brain tissue samples is an essential component of high SNR efficiency MR histology at high magnet fields [MR microscopy]. There is however very little information regarding the rate of ingress and egress of contrast agent from fixed tissue. We present estimates for the enhancement and de-enhancement time constants for perfusion fixed mouse brains within the skull, and propose a method for halting or locking the contrast enhancement at a desired stage for longer term storage prior to MR imaging.

Electron Spin Resonance/Oximetry Hall D Wednesday 13:30-15:30

1725. Oxymetric Imaging in EPR: Single Point Imaging Versus Two-Pulse Echo Imaging Sankaran Subramanian1, Shingo Matsumoto, Sonny Batra, Nallathamby Devasahayam, Fuminori Hyodo, Murali C. Krishna 1National Institutes of Health, Bethesda, USA

Time-domain radiofrequency EPR imaging has been developed to study the distribution of free radicals in vivo and to quantitatively assess the spatial distribution of oxygen non-invasively. Quantitative oxymetry is important in the treatment of tumor by radiation. Oxygen estimates are based on the spatially resolved spectral characteristics (local line width) of the free radical. Two modalities, namely, (a) the 90-τ 80 spin echo and filtered back projection that can provide T2-weighted images, and (b) the single point imaging (with pure phase-encoding and Fourier reconstruction) that can provide a series of T2*-weighted images, are examined for their relative merits.

1726. 3D Superresolution EPR Imaging of Nitroxyl Radicals in Mice Yusuke Ikebata1, Hideo Sato-Akaba1, Hirotada Fujii2, Hiroshi Hirata1 1Yamagata University, Yonezawa, Japan; 2Sapporo Medical University, Sapporo, Japan

We report the superresolution technique of three-dimensional (3D) continuous-wave (CW) EPR imaging of live mice. This post-processing technique could improve the spatial resolution of 3D EPR images. We used anesthetized ICR mice, and administered 0.2-0.25 ml solution of 200 mM 3-hydroxymethyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl (hydroxymethyl-PROXYL) spin probes intraperitoneally. We show a superresolution EPR image that was generated from a blurred image of nitroxyl probes in mouse head.

1727. EPR Imaging of Short-Lifetime Nitroxyl Radicals in Mouse Head Hideo Sato-Akaba1, Hirotada Fujii2, Hiroshi Hirata1 1Yamagata University, Yonezawa, Japan; 2Sapporo Medical University, Sapporo, Japan

Three-dimensional (3D) EPR imaging of 4-Hydroxy-2,2,6,6-tetramethylpiperidine-d17-1-15N-1-oxyl in mouse head was reported. To enable EPR imaging of nitroxyl spin probes that have a half-life of a few minutes possible, the time of field scanning was decreased to 0.5 s in animal experiments. The total acquisition time of 46 projections for a 3D image was achieved at 30 s. Applicability of 3D continuous-wave (CW) EPR imaging to short-lifetime nitroxyl spin probes in animals was demonstrated.

Poster Sessions

295

1728. Nanoencapsulation of Perfluorinated Trityl Radicals and Evaluation as Sensors for EPR Oximetry Nicolas Charlier1, Benoît Driesschaert1, Jacqueline Marchand1, Véronique Préat1, Bernard Gallez1 1Université catholique de Louvain, Brussels, Belgium

Trityls radicals are interesting probes for EPR spectroscopy/imaging as they possess a narrow EPR Line Width (LW) (high signal-to-noise ratio). However, they have a low sensitivity to changes in oxygenation. It is possible to increase the sensitivity by using lipophilic solvent, such as perfluocarbon solvents as they have high oxygen solubility and biocompatibility. We developed a nanoemulsion containing a newly synthesized perfluorinated trityl. X-band measurements of LW were carried out at 21% and 0% and showed LW variation of 2.3G compared to 0.1G for hydrophilic trityl. In vivo results showed that emulsion is higly responsive to subtle pO2 variations.

1729. Molecular Electron Paramagnetic Resonance Imaging of Melanin in Melanomas: A Proof-Of-Concept Nicolas s. Charlier1, Emilia Vanea1, Julie De Wever1, Mustapha Dinguizli1, Olivier Feron1, Jean-François Baurain1, Bernard Gallez1 1Université catholique de Louvain, Brussels, Belgium

Taking into account the abundance of the naturally occurring free radicals (melanin pigments) in proliferating melanocytes and their localization pattern, we hypothesized that EPR Imaging (EPRI) could be a unique tool to map melanomas with high sensitivity and high resolution. The potential of EPR to image melanoma samples was demonstrated in vitro in animal and human samples. Using EPR systems operating at low frequency, we were also able to record in vivo EPR spectra and images from the melanin present in a subcutaneous melanoma implanted in a mouse.

1730. Relationship Between Oxygenation Status and Tumor Metabolites. Noninvasive Evidence for Aerobic Glycolysis (Warburg Effect) in Tumor by Sequential EPR Oxymetric Imaging and MRS Shingo Matsumoto1, Fuminori Hyodo1, Jeeva Munasinghe2, Sonny Batra1, Sankaran Suburamanian1, Nallathamby Devasahayam1, James B. Mitchell1, Murali C. Krishna1 1National Cancer Institute, NIH, Bethesda, Maryland, USA; 2National Institute of Neurological Disorder and Stroke, NIH, Bethesda, Maryland, USA

Tumor hypoxia is an important prognostic factor in radiotherapy, and non-invasive methods to assess tumor hypoxia such as Electron Paramagnetic Resonance Imaging (EPRI) can provide useful a priori information to guide therapy. To investigate the correlation between oxygenation status and tumor metabolites detectable by MR spectroscopy (MRS), we developed a pulsed EPRI 3D oxygen imaging technique that operates at 300 MHz enables to be sequentially combined with 7T MRI/MRS using a common RF coil without disturbing the object. This combined system clearly shown the oxygenation dependent MRS metabolic change in tumor, especially aerobic glycolysis (lactate production) known as Warburg effect.

1731. Surface Coil for EPR Irradiation to Reduce SAR in Fixed-Field PEDRI Keerthi Shet1, 2, Sergey Petryakov3, Jay L. Zweier3 1Ohio State University, Columbus, Ohio, USA; 2Davis Heart and Lung Research Institute, Columbus , Ohio, USA; 3Davis Heart and Lung Research Institute, Columbus, Ohio, USA

Proton Electron Double Resonance Imaging (PEDRI) is a combination of proton nuclear magnetic resonance (NMR) imaging and electron paramagnetic resonance (EPR). The technique involves irradiating a paramagnetic sample at its electron spin resonance and this is followed by NMR signal acquisition to produce an Overhauser enhanced NMR signal. The EPR frequency at about 660 times the NMR frequency and may cause sample overheating if irradiated for longer periods of time. Proposed here is a study that uses surface coils for EPR irradiation instead of whole body EPR coils when the organ of interest is closer to the surface of the sample.

1732. Comparison of Methods to Measure the PO2 Mustapha Dinguizli1, Nelson Beghein1, Bernard Gallez1 1Université Catholique de Louvain, Brussels, Belgium

To clarify the source of discrepancy between pO2 vreported for SC tissue, we used sequential monitoring of pO2 using EPR oximetry and OxyLite probes. Initial pO2 measurements by EPR show low values in subcutaneous area (10 mm Hg). After insertion of the OxyLite probes, the pO2 recorded using this system indicate significant larger values (40 mm Hg). Immediately after the OxyLite measurements, the second EPR measurements indicate systematically pO2 increased compared to the first measurement. While comparison of oximetry methods is generally valuable in deep tissues, the use of invasive methods near the skin potentially disturb the local pO2

1733. Spin Density Distribution in Foodstuff After Heat Treatment or Irradiation Philippe P. Levêque1, Quentin Godechal1, Bernard Gallez1 1Université catholique de Louvain, Brussels, Belgium

Irradiated food can be detected by EPR spectroscopy according to current European Standards. When spatial distribution of spin densities is needed, EPR imaging can be used to locate radicals in biomaterial.We applied on going developments of this technique to study spin density distribution in irradiated frog-leg and roasted coffee bean, as an illustration of the instrumentation capabilities.In irradiated frog leg, spin density is concentrated in bone tissue, whereas in roasted coffee bean it follows a gradient from the center to the edges.EPR imaging offers unique capabilities to monitor the fate of free radicals in biological sample.

Poster Sessions

296

Non-Proton MRI Hall D Thursday 13:30-15:30

1734. Natural Abundance 17O NMR Spectroscopy of Rat Brain In Vivo Robin A. de Graaf1, Peter B. Brown1, Kevin L. Behar1 1Yale University, New Haven, Connecticut, USA

Despite the rich abundance of oxygen in biologically relevant compounds, oxygen detection by NMR is limited largely by the low natural abundance of oxygen-17 (0.037%) and the broad resonances (spin 5/2). However, the favorable T1 relaxation constants, together with the increased spectral dispersion and sensitivity at high magnetic fields allowed the detection of natural abundance 17O NMR spectra from rat brain in vivo. A large number of resonances originating from phosphate, sulfate and carbonyl groups were readily detected.

1735. Evaluation of Lung Tumor Oxygenation in Rats Using FREDOM Jesus Pacheco1, 2, Dawen Zhao1, Vikram D. Kodibagkar1, Angelina Contero1, Debabrata Saha3, Sebastian Cerdan2, Ralph P. Mason1 1University of Texas Southwestern Medical Center, Dallas, Texas, USA; 2Instituto de Investigaciones Biomédicas "Alberto Sols" - CSIC, Madrid, Spain; 3University of Texas Southwestern Medical Center, Dalas, Texas, USA

Hypoxia is recognized to influence tumor response to therapy. 19F MRI using the reporter molecule hexafluorobenzene has been demonstrated to measure pO2 dynamics in tumors growing in animals- the FREDOM approach. Here, we explore the use of FREDOM to evaluate pO2 distributions and response to hyperoxic gas breathing in H460 lung tumor xenografts growing in rats. Oxygenation is found to range from hypoxia to well oxygenated and the H460 tumors are found to be highly responsive to hyperoxic gas breathing. The regions, which are initially best oxygenated showed greatest response. These results show further application of 19F MRI oximetry.

1736. Fluorinated Anaesthetics Uptake Kinetic Investigation on Large Animal Model Using 19F MRS/MRI Maxim Terekhov1, Alexander Scholz2, Ursula Wolf1, Julien Rivoire1, Wolfgang Schreiber1 1Mainz University Medical School, Mainz, Germany; 2Mainz University Medical School,, Mainz, Germany

MRS and MRI of drugs are emerging tools in the development and understanding of pharmacons. Some drugs, e.g. the inhaled anesthetics such as sevoflurane, embody fluorine. In these cases, 19F MRI allows for in vivo imaging.without background signal. We established a large animal model for NMR/MRI investigations of fluorinated anesthetics at 1.5T medical scanner that may be considered as a further step towards human studies. This imaging and spectroscopy techniques may allow for a regional analysis of pharmacokinetic and better understanding of molecular interactions of inhaled anesthetics.

1737. Phase Contrast MRI of 19F and 3He Gas Flow: Phantom Studies

Daniel Kalthoff1, 2, Ursula Wolf1, Kerstin Münnemann1, Wolfgang Günther Schreiber1 1Mainz University Medical School, Mainz , Germany; 2Max Planck Institute for Neurological Research, Cologne, Germany

A method of phase contrast MRI was implemented to study flow of 3He and especially 19F gases which are currently used in lung imaging. Experiments were performed on a custom-made gas flow phantom that produced a continuous gas flow with in-vivo-like characteristics in flow rates and geometry. Turbulent and laminar flow were observed as expected in C4F8 and 3He respectively. A comparison of MRI data to simultaneous flow sensor measurements showed excellent agreement and verified the accuracy of the presented method. Thus, phase contrast MRI of 19F and 3He appears to suitable for quantitative investigation of lung ventilation.

1738. Reduction of Chemical Shift Artifacts in 19F Imaging Utilizing Coil Sensitivities Oliver Lips1, Jochen Keupp1 1Philips Research Europe, Hamburg, Germany

19F-MRI bears potential as a tracer technique for applications in diagnosis and therapy monitoring when combined with fluorine-labeled agents. However, 19F-MRI suffers from chemical shift (CS) artifacts due to multi-line spectra of typical 19F-agents or the presence of multiple agents exhibiting different CS. Hence, countermeasures are needed, which do not spoil the SNR or significantly increase scan time. A concept is presented, which utilizes different coil sensitivity profiles to correct for CS artifacts applying a SENSE-like algorithm in the frequency encoding direction. Simulations and initial experiments were performed. The results indicate, that the method has potential to improve multi-line 19F-imaging.

1739. 19F MR for Drug Delivery Research Xin Liu1, Zhong-Xing Jiang1, Y. Bruce Yu2, Eun-Kee Jeong1 1University of Utah, Salt Lake City, USA; 2University of Maryland, College Park, USA

1H MR imaging of water protons in tissue is widely used for studying the pharmacokinetics of Gd-chelate based endogenous contrast agent. The concentration of the delivered compound is indirectly measured by analyzing the change in the proton MRI signal intensity. this method is not practical in most of dynamic MR imaging due to the long imaging time for T1 mapping. In this report, 19F MRI is presented as an alternative method to access the drug quantity. The concentration of fluorine compound is directly proportional to the 19F signal in density weighted 19F-MRI.

1740. Combining Tissue Segmentation with Quantitative 31P and 1H MRSI Can Resolve the Distribution of Three Trimethylamine Components in Gray and White Matter Joerg Magerkurth1, Ulrich Pilatus1 1Johann Wolfgang Goethe Universität, Frankfurt a. M., Germany

Voxelwise coregistration for combining quantitative 31P and 1H MR spectroscopy ishampered by the rather large voxel size and the poor point-spread-function (PSF) of 31PMRSI data. The problem can be addressed by minimizing the partial volume effects usingimage segmentation and linear regresson analysis as described previously for 31P and 1H. The approach was evaluated to determine concentration differences between gray and whitematter for the three components of the trimethylamine (tCho) signal at 3.2 ppm in 1HMRSI. This study demonstrates that application of tissue segmentation in combination with quantitative 31P and 1H MRSI can resolve the distribution of these components in gray andwhite matter.

Poster Sessions

297

1741. Preliminary Results of 31P MR Imaging at 9.4T Using a RARE Sequence Aiming Lu1, Ian C. Atkinson1, Xiaoong Joe Zhou1, Theodore Claiborne1, Keith R. Thulborn1 1Univ. of Illinois at Chicago, Chicago, Illinois, USA

31P MRI can provide quantitative bioenergetic information of human brain non-invasively. However, quantitative determination of the spatial distribution of 31P is challenging due to its low MR sensitivity. With the increased sensitivity at 9.4T, initial 31P images with reasonable SNR have been obtained on a phantom with concentration comparable to that of PCr in human brain within 10 minutes using a RARE sequence, which demonstrates the potential of quantitative 31P metabolic imaging at 9.4T.

1742. Optimization of Xenon Biosensors for Increased Sensitivity Tyler Meldrum1, Monica A. Smith1, Leif Schroeder1, Thomas Lowery1, David Wemmer1, Alex Pines1 1University of California, Berkeley, Berkeley, California , USA

We have developed a modular approach to xenon-based biosensor synthesis that facilitates optimization of the sensors for increasing sensitivity. By synthesizing a biosensor with a negatively-charged side chain, together with increased temperature (37 C) and the HYPER-CEST detection method, we can detect biosensor concentrations as low as 10 nM.

1743. Measurement of Pressure from the Diffusion Coefficient of 3He Gas Jim M. Wild1, Steven R. Parnell1 1University of Sheffield, Sheffield, UK

Non-invasive measurement of pressure with NMR could have a variety of applications in-vivo (e.g. measurement of blood pressure) and in non-medical applications (e.g. pressure jets in fluid dynamics). In this work an inverse relation between the pressure of 3He and the measured (apparent) diffusion coefficient (D) was observed using intermediate diffusion time pulsed gradient spin echo (PGSE) methods. Extension of the technique for measuring pressure in-vivo in micro bubbles is proposed using different gas mixtures and short time scale diffusion sequences.

1744. Are We Nearly There Yet? Cardiac 23Na Imaging at 3T Using a 3D Ultrashort TE Acquisition and Phased-Array Reception Matthew David Robson1, Stefan Neubauer1 1Oxford University, Oxford, UK

We have implemented and evaluated a 3D stack of spokes acquisition at 3T using an 8-channel phased array sodium coil. This incorporates an ultra-short TE readout, and can be run as an SSFP sequence. This combination of technologies boosts the signal to noise, and provides higher image quality than have previously been demonstrated.

Hyperpolarized 13C & Other Nuclei Hall D Monday 14:00-16:00

1745. In Vivo Carbon-13 Dynamic MRS and MRSI of Rat Liver with Hyperpolarized 13C-1-Pyruvate Simon Hu1, 2, Albert P. Chen1, Matthew L. Zierhut1, 2, Robert Bok1, 2, Mark Van Criekinge1, Yi-Fen Yen3, Marie A. Schroeder4, Ralph E. Hurd3, Sarah J. Nelson1, 2, John Kurhanewicz1, 2, Daniel B. Vigneron1, 2 1University of California at San Francisco, San Francisco, California , USA; 2UCSF & UCB Joint Graduate Group in Bioengineering, San Francisco, California , USA; 3GE Healthcare, Menlo Park, California , USA; 4University of Oxford, Oxford, UK

Previous studies have demonstrated the ability to detect uptake and metabolism of hyperpolarized 13C pyruvate through non-localized dynamic MRS spectra in normal rats. This study was designed to obtain and characterize hyperpolarized 13C dynamic spectra localized to the liver and to investigate differences between non-fasted and fasted rats. Following fasting, we observed significantly altered 13C-alanine levels in the liver, which agrees with prior biochemical studies showing elevated levels of alanine aminotransferase during fasting. This study demonstrated that hyperpolarized 13C MR can detect significant changes in liver metabolic states in vivo and may be valuable for liver disease state studies.

1746. Pulse Sequence for Dynamic Volumetric Imaging of Hyperpolarized Metabolic Products Charles H. Cunningham1, Albert P. Chen2, Michael Lustig3, Janine Lupo2, Duan Xu2, John Kurhanewicz2, Ralph E. Hurd4, John M. Pauly3, Sarah J. Nelson2, Daniel B. Vigneron2 1Sunnybrook Health Sciences Centre, Toronto, Canada; 2UCSF, San Francisco, California , USA; 3Stanford University, Stanford, California , USA; 4ASL, GE Healthcare, Menlo Park, California , USA

A spectral-spatial excitation pulse was designed to excite a single line of the spectrum resulting from metabolism of hyperpolarized carbon-13. The pulse was implemented along with an echo-planar readout trajectory to give volumetric coverage every 3.5 seconds. The pulse sequence was applied to measure the different lactate dynamics in different tissues in a normal rat model and a mouse model of prostate cancer. The results suggest that significantly different dynamic curves can be observed in tumour vs. non-cancerous tissue.

1747. Apparent T2 of 13C-Labeled Metabolites In Vivo Yi-Fen Yen1, Patrick Le Roux2, Robert Bok3, Jim Tropp1, Albert Chen3, Vickie Zhang3, Matthew Zierhut3, 4, Mark Albers3, 4, Ilwoo Park3, 4, Sarah Nelson5, Dan Vigneron3, John Kurhanewicz3, Ralph Hurd1 1GE Healthcare, Menlo Park, California , USA; 2GE Healthcare, France; 3University of California, San Francisco, California , USA; 4Berkeley, California , USA; 5UCSF, San Francisco, California , USA

Apparent T2 relaxation time of 13C-labeled metabolites was measured for the first time in animals, following an injection of hyperpolarized 13C-pyruvate solution. Pyruvate and its metabolic products such as lactate, alanine and bicarbonate, were observed in the T2 measurements. A CPMG sequence was employed to acquire spectra at every spin echo for total of 8-10 seconds. The T2-decay curves were best described by multiple T2 components. The in vivo T2 results presented here are valuable for future sequence designs in13C metabolic imaging applications. The T2 information may also have diagnostic value as T2 may vary between healthy and diseased tissues.

Poster Sessions

298

1748. First Studies with Hyperpolarized [2-13C]pyruvate in the Rat Brain Isabelle Iltis1, Dinesh Kumar Deelchand1, Malgorzata Marjanska1, Christopher Nelson1, Kamil Ugurbil1, Pierre-Gilles Henry1 1Center for Magnetic Resonance Research, Minneapolis, Minnesota, USA

In this work, we successfully hyperpolarized [2-13C]pyruvate and measured hyperpolarized 13C signals in the rat brain in vivo following i.v. injection of the molecule. Resonances from [2-13C]pyruvate, [2-13C]pyruvate hydrate and [2-13C]lactate, but not from TCA cycle intermediates, were observed. The T1 relaxation time of [2-13C]pyruvate was on the order of 15 s in vivo.

1749. Combined Reconstruction of Rosette Sampled Data for Hyperpolarised 13C Metabolic Imaging Rolf F. Schulte1, Florian Wiesinger1, Ileana Hancu2 1GE Global Research, Munich, Germany; 2GE Global Research, Niskayuna, New York, USA

Metabolic imaging with hyperpolarised 13C requires rapid acquisition sequences in order to encode both spectrally and spatially with a high resolution. The rosette trajectory is one of the most efficient acquisition sequences with a high spectral selectivity, however at the cost of a high sensitivity towards B0 inhomogeneities. Including as much physical information as possible improves the robustness considerably. In this work, we combine coil sensitivities, B0 correction and chemical shifts in one reconstruction. The encoding model is extended by this information and solved with conjugate gradient iterative reconstruction. Simulations, in-vivo and in-vitro scans show promising results.

1750. Parallel Imaging with GRAPPA CSI for Hyperpolarised 13C Metabolic Imaging Rolf F. Schulte1, Arjun Arunachalam2, Kenneth M. Fish3, David B. Whitt3, Florian Wiesinger1, James Tropp4, Ileana Hancu2 1GE Global Research, Munich, Germany; 2GE Global Research, Niskayuna, New York, USA; 3GE Global Research, Niskayuna, USA; 4GE Healthcare, Menlo Park, California , USA

Metabolic imaging of hyperpolarised 13C1-pyruvate was combined with parallel image CSI acquisition and GRAPPA reconstruction. A custom-built, four-channel rat-coil was used for signal acquisition after injecting hyperpolarised 13C1-pyruvate in a rat. Data was acquired with a fully-sampled FID CSI sequence with a spatial and spectral resolution of 24x24 and 256, respectively. The spectral dimension was reconstructed by chemical-shift modelling (matrix inversion) to the three resonances (pyruvate, alanine/pyruvate-ester and lactate). One GRAPPA kernel was fitted from the k-space centre for the three resonances The data was artificially undersampled and then GRAPPA interpolated to yield the same metabolic maps as from the fully sampled data.

1751. Sensitivity Mapping for Parallel Imaging of Hyperpolarized 13C Compounds Daniel Blezek1, 2, Arjun Arunachalam1, David Whitt1, Kenneth Fish1, Ileana Hancu1 1GE Research, Niskayuna, New York, USA; 2Mayo Clinic, Rochester, Minnesota, USA

Coil sensitivity profiles for hyperpolarized 13C compounds may be acquired in phantoms prior to actual scanning. Low coil loading permits profiles to be measured once for rigid geometry coils. We have developed a method to register pre-acquired sensitivity profiles to 13C-pyruvate acquisition using fudical spheres rigidly affixed to the coil. A 13C-acetate and 23Na phantom were constructed and imaged. Using a custom 4 channel rat-sized coil, we compare 13C-pyruvate rat images reconstructed from fully sampled signals to SENSE recon using self-calibrated profiles(R=1.5), pre-acquired 13C-acetate(R=2) and 23Na profiles(R=2). Parallel imaging results compare favorably with full reconstruction.

1752. Accelerated Imaging of Hyperpolarized Carbon-13 Compounds Arjun Arunachalam1, David Whitt1, Kenneth Fish1, Randy Giaquinto1, Ileana Hancu1 1GE Global Research Center, Niskayuna, New York, USA

The long scan time characteristic of traditional chemical shift imaging sequences (CSI) is a major limitation for metabolic imaging of hyperpolarized compounds. In this work, the ability to accelerate the spatial encoding process during a CSI scan of hyperpolarized compounds is demonstrated in vivo through parallel imaging. A hardware set up designed to acquire 13C signal data from multiple receivers simultaneously is presented and the ability to perform parallel imaging is demonstrated in vivo. The CSI data from the accelerated scans is reconstructed using self-calibrated SENSE, by using coil sensitivity maps obtained from the central region of k-space.

1753. Hyperpolarized 13C MRI with a Triple-Frequency RF Coil S. James Wood1, Brian K. Rutt1, Joseph Piel2, David B. Whitt2, Kenneth M. Fish2, W. Thomas Dixon2, Ileana Hancu2 1Robarts Research Institute, the University of Western Ontario,, London, Canada; 2GE Global Research Center, Niskayuna, New York, USA

Imaging 13C hyperpolarized compounds requires new MR hardware capabilities. 1H imaging is required for anatomical localization and shimming. Accurate flip angle calibration for 13C scans can be performed using natural abundance 23Na signal. We demonstrate here a triple-frequency RF resonant structure, which mitigates signal loss of previous designs and eliminates the need for multiple coils. In vivo, hyperpolarized 13C experiments are demonstrated where images are acquired sequentially at 1H, 23Na, and 13C frequencies without moving the coil or specimen. Proton, sodium, lactate, and pyruvate images are acquired; as expected, high 23Na and 13C signals are visible over the kidneys.

1754. Time-Resolved Metabolic Imaging in the Rat After Injection of Hyperpolarized 13C-1-Pyruvate at 3 Tesla Dirk Mayer1, 2, Yi-Fen Yen3, Yakir S. Levin1, James Tropp3, Adolf Pfefferbaum, 12, Ralph E. Hurd3, Daniel M. Spielman1 1Stanford University, Stanford, California , USA; 2SRI International, Menlo Park, California , USA; 3GE Healthcare, California , USA

This work reports on the development of rapid time-resolved 13C spiral chemical shift imaging for the assessment of localized metabolic parameters. The sequence was tested at 3 Tesla on a phantom to measure the longitudinal relaxation constant of hyperpolarized 13C-1-pyruvate. In the in vivo application, the time course of pyruvate, lactate, and alanine were measured in the kidneys and the liver of a rat after tail vein injection 1 ml of hyperpolarized 13C-1-pyruvate.

Poster Sessions

299

1755. Ultra-Fast in Vivo Metabolic Imaging in the Rat After Injection of Hyperpolarized 13C-1-Pyruvate at 3 Tesla Dirk Mayer1, 2, Yi-Fen Yen3, Yakir S. Levin1, James Tropp3, Adolf Pfefferbaum, 12, Ralph E. Hurd3, Daniel M. Spielman1 1Stanford University, Stanford, California , USA; 2SRI International, Menlo Park, California , USA; 3GE Healthcare, California , USA

A fast spiral chemical shift imaging sequence has been developed for application in hyperpolarized 13C imaging. The sequence exploits sparse spectra and prior knowledge of resonance frequencies to reduce the measurement time by undersampling the data in the spectral domain. Multiple data sets having only frequency components within a certain bandwidth are reconstructed “in-focus” while others are severely blurred (“spectral tomosynthesis”). The sequence was applied to sub-second metabolic imaging of the rat in vivo after injection of hyperpolarized 13C-1-pyruvate.

1756. Detection and Imaging of Hyperpolarized 6-Lithium in the Rat Brain in Vivo Ruud Bernardus van Heeswijk1, Kai Uffmann1, Arnaud Comment1, Fiodar Kurdzesau1, 2, Chiara Perazzolo1, Cristina Cudalbu1, Sami Jannin1, J.A. Konter3, Patrick Hautle2, Ben van den Brandt2, Jacques J. van der Klink1, Gil Navon4, Rolf Gruetter1, 5 1Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; 2Paul Scherrer Institute, Villigen, Switzerland; 3Paul Scherrer Institute, Villigen, Switzerland; 4Tel Aviv University, Tel Aviv, Israel; 5Universities of Lausanne and Geneva, Switzerland

This study focused on the feasibility and characterization of the usage of in vivo hyperpolarized lithium-6. Therefore, hyperpolarized lithium-6 chloride was infused in the rat femoral vein. Pulse-acquire as well as fast spectroscopic imaging were used to study the signal decay and spatial distribution of the lithium in the rat head. The relaxation time appeared to change over time from an initial 32 to 94 s and was detectable up to five minutes after dissolution. The spectroscopic imaging demonstrated that lithium appears to distribute in the brain.

1757. A Simple, Low-Cost Device for Producing Hyperpolarized Heteronuclear Contrast Agents Using Parahydrogen-Induced Polarization Stephen Kadlecek1, Vahid Vadhat1, Robert V. Cadman1, Kiarash Emami1, John MacDuffie Woodburn1, Richard A. Guyer1, Masaru Ishii, 12, Jiangsheng Yu1, Hans Hyonchang Kim1, Warren Gefter1, Rahim R. Rizi1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA; 2Johns Hopkins University, Baltimore, Maryland, USA

We present the essential design details for a device which produces hyperpolarized, 13C-containing solutions using the spin-order derived from parahydrogen. The device provides flexible conditions for changing the target molecule and optimizing hydrogenation chemistry. It is based on a small jet reactor, which is housed in a low-field, transmit-only NMR apparatus. Preliminary results hyperpolarizing several 13C-labeled molecules is presented.

1758. A Mobile DNP Polarizer for Clinical Applications Kerstin Münnemann1, Christian Bauer2, Jörg Schmiedeskamp2, Hans Werner Spiess2, Wolfgang G. Schreiber1, Dariush Hinderberger2 1Mainz University Medical School, Mainz, Germany; 2Max-Planck-Institute for Polymer Research, Mainz, Germany

A mobile and low cost apparatus for DNP hyperpolarization is presented and its performance is demonstrated at room temperature and with three radical species. DNP enhancement factors for a triarylmethyl-based radical (TAM), TEMPOL and a polyelectrolyte spin-labeled with nitroxide radicals are measured as a function of mi-crowave power and the projected maximum enhancement factors are compared. The spin-labeled polyelectro-lyte shows the best DNP efficiency and 1H DNP enhancement factors up to -50 were observed. The results demonstrate that we are able to perform reliable DNP experiments in the proposed mobile apparatus and to ob-tain reasonably high 1H-DNP enhancements.

1759. Hyperpolarization of Hetero Nuclei Via Adiabatic Field Cycling of Parahydrogenated Molecules Bob C. Hamans1, Anna Andreychenko2, Sybren S. Wijmenga2, Arend Heerschap1, Marco Tessari2 1Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands; 2Radboud University Nijmegen, Nijmegen, Netherlands

Para-hydrogen induced polarization (PHIP) makes use of the macroscopic spin order contained in para-hydrogen gas (pH2) to produce hyperpolarization. Field cycling following a para-hydrogenation reaction allows for polarization transfer from the pH2 protons to other protons and hetero nuclei (e.g. 13C, 31P) of the hydrogenated substrates. A complete numerical simulation of this field cycling experiment is of great help in the selection of the optimal biologically interesting para-hydrogenatable substrates as well as for determining optimal field cycling conditions.

1760. New Hyperpolarized Agents from Para-Hydrogenation of 13C-Labelled Butynoic Acid and Methylbutynoate Alessandra Viale1, Daniela Santelia1, Francesca Reineri1, Roberta Napolitano1, Roberto Gobetto1, Silvio Aime1 1University of Torino, Torino, Italy

Para-hydrogenations of butynoic acid and its methyl ester (both protonated and deuterated) yield 13C signal enhancements in the reaction products, useful for 13C-MRI. Since the hydrogenation yield is higher for the ester and it is well soluble in water, it has been used to produce 13C MR images.

1761. Method for Measuring Spin Relaxation During Production of Hyperpolarized 13C Robert V. Cadman1, Stephen Kadlecek1, Kiarash Emami1, Richard A. Guyer1, Masaru Ishii, 12, Hans Hyonchang Kim1, Vahid Vadhat1, John MacDuffie Woodburn1, Jiangsheng Yu1, Rahim R. Rizi1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA; 2Johns Hopkins University, Baltimore, Maryland, USA

We perform a numerical calculation of the effect of relaxation during a pulse sequence used to transfer spin order from protons in a state with total spin zero to a heteronucleus. We propose that by measuring polarization resulting from a variety of pulse sequences, the relaxation time constants may be determined. Knowledge of relaxation time constants would allow for better optimization of the pulse sequences.

1762. Sensitivity Enhancement of Hyperpolarized Nuclei Through Polarization Transfer Stephen Kadlecek1, Kiarash Emami1, Vahid Vadhat1, Jiangsheng Yu1, Richard A. Guyer1, Robert V. Cadman1, Masaru Ishii, 12, John MacDuffie Woodburn1, Hans H. Kim1, Warren Gefter1, Rahim R. Rizi1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA; 2Johns Hopkins University, Baltimore, Maryland, USA

We demonstrate a technique for enhancement of hyperpolarized heteronuclear sensitivity by transferring polarization to a vicinal, higher-gyromagnetic ratio nucleus. Phantom imaging results provide evidence that significant signal-to-noise gains can be achieved without sacrificing the advantages of a negligible background when imaging the heteronucleus directly. Efficient transfer can be achieved despite the non-ideal nature (low-power pulse, unavoidable between-pulse delays) of a clinical MRI environment.

Poster Sessions

300

1763. Mimicking the Role of NADH and FADH2 with Homogenous Hydrogenation Catalysts and Parahydrogen Providing 13C-Hyperpolarized Biochemical Intermediates for 13C-MRI or 13C-MRS Joachim Bargon1, 2, Ute Bommerich3, Matthias Stephan1, Rahim R. Rizi2 1University of Bonn, Bonn, Germany; 2University of Pennsylvania Medical Center, Philadelphia, Pennsylvania, USA; 3Leibniz Institute for Neurobiology, Magdeburg, Germany

The role of both enzyme-mediated biochemical redox systems, flavin adenine dinucleotide (FAD), the precursor molecule to 1,5-dihydro-FAD (FADH2), and nicotinamide adenine dinucleotide (NAD+) and its reduced form, NADH, can be mimicked by water-soluble homogeneous hydrogenation catalysts, which convert the unsaturated forms into their saturated derivatives. In connection with parahydrogen both proton and 13C-hyperpolarization result, which boosts the sensitivity of 13C-MRS and -MRI by some orders of magnitude. In this fashion various intermediates, for example of the degradation and synthesis of fatty acids and amino acids have been hyperpolarized successfully. Characteristic examples include glutamate, amino butyrate, succinate, fumarate, L-DOPA, etc.

1764. Investigating the Metabolism of Glucose: An Alternative to 13C-Hyperpolarized Pyruvate Joachim Bargon1, 2, Rahim R. Rizi, 12 1; 2University of Pennsylvania Medical Center, Philadelphia, Pennsylvania, USA

Water-soluble chiral homogeneous Rh(I)-hydrogenation catalysts containing ligands derived from the chiral pool of natural sugars hydrogenate glucose-derived unsaturated precursors to yield hyperpolarized derivatives boosting the sensitivity of 13C-MRI or 13C-MRS, providing an alternative to hyperpolarized pyruvate. The 1H-PHIP spectra reveal the formation of intermediate complexes consisting of the catalyst and the unsaturated substrate. The number of possible stereoisomers of these intermediates depends on the symmetry of the ligands used. The spectral analysis of these intermediates yields information about the enantiomeric purity of the hydrogenation product formed. For hyperpolarizing glucose this is of special importance since only D-glucose can be metabolized.

1765. Providing 13C-Hyperpolarized Nicotine Derivatives for Use in 13C-MRI or 13C-MRS Joachim Bargon1, Ute Bommerich2, Achim Koch3, Rahim R. Rizi4, Meike Roth3, Jorg Schmiedeskamp3, Hans W. Spiess3 1University of Bonn, Bonn, Germany; 2Leibniz Institute for Neurobiology, Magdeburg, Germany; 3Max-Planck Institute for Polymers, Mainz, Germany; 4University of Pennsylvania Medical Center, Philadelphia, Pennsylvania, USA

13C-hyperpolarized alkylated nicotines mimic neurotransmitters like acetylcholine, but unlike those they readily and hence quickly penetrate the blood-brain barrier. Nicotine derivatives are considered as medications to treat Parkinson's disease, Alzheimer's disease, schizophrenia, depression, anxiety or pain. On the other hand, nicotine serves an important role in provi-ding pleasure and relaxation. Due to its addictive properties, quitting smoking is difficult, even though the consequences of smoking health-wise are severe. 13C-hyperpolarized nicotines are a prerequisite applying 13C-MRI or 13C-MRS due to the low sensitivities of these methods. The required unsaturated precursors are readily synthesized. SIB-1509Y is a drug itself.

1766. Observation of Anomalously Long-Lived Hyperpolarized C13 States in Parahydrogen-Induced Polarization< Aaron K. Grant1, Elena Vinogradov1 1Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA

Hyperpolarized contrast media based on nuclei such as 13C yield dramatic enhancements of signal-to-noise ratio in MRI. The comparatively short T1 relaxation time of the available agents presents a challenge to applications of hyperpolarization. Recent observations have shown that certain quantum-mechanical spin states possess relaxation times significantly longer than T1 when they are stored under low field conditions. Measurements in parahydrogen-induced polarization have demonstrated significant lifetime enhancements in homonuclear proton systems, but large enhancements have not been observed in heteronuclear systems. Here we present observations in a heteronuclear system where a carbon in a ‘CH’ group possesses an anomalously long lifetime.

1767. Conservation of Hyperpolarized Long-Lived States in Low Field: Theory and Experiment Elena Vinogradov1, Aaron K. Grant1 1Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA

Hyperpolarized liquid-phase contrast media dramatically improve the sensitivity of MRI. Although the signal enhancements achieved with hyperpolarization are dramatic, they are also short-lived owing to the comparatively short T1 relaxation times of the available agents. Recent observations have shown that certain quantum-mechanical states can have lifetimes significantly longer than T1. Here we present results of theoretical and experimental work on long-lived states in three- and four-spin systems at low field. We document a long-lived state in hyperpolarized ethyl acrylate, and describe how a ‘bottleneck’ in the relaxation process accounts for the observed time dependence of NMR spectra from this compound.

1768. MRI of Hyperpolarized 3He at 3T Kevin Teh1, Nicola de Zanche2, Salma Ajraoui1, Matthew Clemence, Klaas Pruessmann2, Jim M. Wild1 1University of Sheffield, Sheffield, UK; 2University and ETH Zürich, Zurich, Switzerland

The optimum B0 field strength for hyperpolarised (HP) MRI experiments is the subject of some discussion. The non-Boltzmann polarisation (achieved here with laser optical pumping) makes the magnetisation independent of B0, and low field MRI becomes a realistic possibility. Furthermore the field inhomogeneity at high B0 in the lungs makes the use of higher fields for lung imaging more challenging. Nevertheless, MRI manufacturers are shifting their multinuclear engineering focus on to higher B0 systems and engineering quality as well as electromagnetic physics will ultimately determine SNR in practice. The objective of this work was to investigate the feasibility of HP 3He MRI at 3T on a whole body system. The engineering aspects of upgrading our 3T system for 3He transmit receive are presented. Preliminary imaging results and SNR comparisons are made with data acquired at 1.5T with non-lossy 3He samples and coils of the same size and geometry.

1769. Radiation Damping as a Diagnostic Tool for 3He Polarimetry in Optical Pumping Cells Steven R. Parnell1, 2, Steven Boag2, Max Skoda2, Chris D. Frost2, Jim M. Wild1 1University of Sheffield, Sheffield, UK; 2Rutherford Appleton Laboratories, UK

For hyperpolarised 3He, accurate measurement of the polarisation is necessary. In-situ polarimetry of gas in the cell typically relies on small tip angle NMR from a coil close to the cell. In this work we investigate the effects of the high magnetisation on the observed FID from the optical pumping cell in both the high and low energy states and the effect of radiation damping on the observed total magnetisation.

Poster Sessions

301

1770. Pulmonary Oxygen Mapping with 3He MRI at Very-Low-Field Ross William Mair1, Rachel Nora Scheidegger1, 2, Leo Lee Tsai, 23, Matthew Scott Rosen1, 4, Ronald Lee Walsworth1, 4 1Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts, USA; 2Harvard-MIT Division of Health Sciences and Technology, Cambridge, Massachusetts, USA; 3Harvard Medical School, Boston, Massachusetts, USA; 4Harvard University, Cambridge, Massachusetts, USA

The partial pressure of oxygen in the lung may be derived from the attenuation of the 3He MRI signal, if the RF flip-angle is precisely known. In clinical MRI systems this measurement is non-trivial, due to coil-loading effects of different human subjects and the B1 inhomogeneity of RF coils used at high field. Therefore, flip-angle calibrations are incorporated into every measurement. We employ an open-access, very-low-field human MRI system to study posture-dependent effects on pulmonary function. Operation of this system at 210 kHz has resulted in a simplification of the pulmonary oxygen measurement technique in comparison to high-field methods.

1771. High Production of Hyperpolarized Helium-3: Commercial Prototype Iulian C. Ruset1, 2, David Watt1, Jan Distelbrink1, Adam Straub1, John Brackett1, Edward J. Kotkowski2, Chad D. Everbeck2, Korac MacArthur1, Alex J. Johnston2, Peter L. Conti2, F.W. W. Hersman1, 2 1Xemed LLC, Durham, New Hampshire, USA; 2University of New Hampshire, Durham, New Hampshire, USA

We present a commercial prototype for the high-production of hyperpolarized helium-3. The system is based on hybrid-alkali optical-pumping using kilowatt laser power. The polarizing cell is a large eight liter cylinder placed inside a pressure aluminum vessel which minimizes the stress on the glass. A gas line designed to minimize polarization losses and alkali diffusion allows for helium removal and renewal. The system is envisioned to produce 100 liters/day at 70% hyperpolarized helium-3. Preliminary tests confirmed the feasibility of the system. Polarization was limited to few percent by the low relaxation time of the Pyrex cell used. Improvements are underway.

1772. Accelerated 3D Imaging of Oxygen Partial Pressure Using Projection Acquisition and Constrained Reconstruction Rafael Luis O'Halloran1, James Hartman Holmes1, Sean Bedillion Fain1 1University of Wisconsin, Madison, Wisconsin, USA

A 3D stack-of-stars acquisition for oxygen partial pressure and flip angle parametric mapping in hyperpolarized helium-3 MRI is presented, validated in a phantom and demonstrated in a healthy volunteer. The acquisition provided 10 axial slices at 16 distinct time-points within a 16 s breath-hold. Measured oxygen pressures matched previously observed values in human lung and demonstrated the known anterior/posterior dependence in the supine position.

1773. Evaluation of Dynamic Lung Function Using Non-Equilibrium Xenon Uptake Spectroscopy (NEXUS) Kai Ruppert1, Jaime F. Mata2, Talissa Altes1, James R. Brookeman2, Klaus D. Hagspiel2, John P. Mugler III2 1The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA; 2University of Virginia, Charlottesville, Virginia , USA

Non-Equilibrium Xenon Uptake Spectroscopy (NEXUS), an extension of a commonly-used hyperpolarized xenon-129 MRS pulse sequence, might provide unique insights into the lung-function dynamics of a freely breathing subject that far exceed those of conventional spirometry. For instance, the gas transit time to travel to the alveolar gas-exchange sites might become an indicator of small airway disease. Other applications for NEXUS might include a free-breathing exam in children who cannot perform forced respiratory maneuvers. Also, with a temporal resolution of 30ms or better, which is much greater than that of any existing technique, not even a breath hold would be required.

1774. Temperature-Sensitive Imaging by Means of Exchangeable Functionalized 129Xe Monica A. Smith1, 2, Leif Schröder1, 2, Tyler Meldrum1, 2, Thomas J. Lowery1, 2, Alexander Pines1, 2, David E. Wemmer1, 2 1University of California, Berkeley, Berkeley, California , USA; 2Lawrence Berkeley National Laboratory, Berkeley, California , USA

Recent advances using functionalized 129Xe biosensors and hyperpolarized chemical exchange saturation transfer (HYPER-CEST) have overcome some of the intrinsic limitations when using 129Xe as a contrast agent, but additional gains in sensitivity are required for use of these methods in vivo. Here, the effect of increasing the temperature of the system was investigated. It was shown that HYPER-CEST contrast increased when the temperature was increased from 26 C to 32 C. Preliminary data suggests that additional contrast is achievable at body temperature, which holds promise for in vivo applications.

1775. Absolute Quantification of Pulmonary Perfusion Using Intravenous Injection of Hyperpolarized 129Xe Harald E. Möller1, Bastiaan Driehuys2, James Pollaro2, Laurence W. Hedlund2 1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; 2Center for In Vivo Microscopy, Durham, North Carolina, USA

Recently, a means of lung perfusion imaging based on intravenous injection of hyperpolarized 129Xe dissolved in saline was proposed. Combination of such images with information obtained from serial gas-phase spectroscopy allows quantification of global lung perfusion. This information that can be used for scaling the image to obtain maps of regional lung perfusion in absolute units.

1776. Hyperpolarized Xenon at 10 Liters Per Hour for Diagnostic MRI Jan Distelbrink1, Jeff Ketel1, David Watt1, Adam Straub1, Iulian C. Ruset1, 2, Walt Porter1, Stephen Ketel1, John Brackett1, Aaron Hope1, Korac MacArthur1, Silviu Covrig2, F.W. W. Hersman1, 2 1Xemed LLC, Durham, New Hampshire, USA; 2University of New Hampshire, Durham, New Hampshire, USA

We present a compact system for high polarization, high volume (50% at 10 liters/hr) production of hyperpolarized xenon. Preparations to build production units have started. The system is based on the existing 1 liter/hr Xemed XeBox-B polarizer. Its 2” diameter glass column was replaced by a 6” square copper column for increased gas flow and dissipation of heat from the 800 Watt wavelength narrowed CW laser. An on-board computer controls the polarizer. Automated operation is facilitated by a web-based interface. Compliance with FDA 21 CFR 210 and 21 CFR 211 is anticipated.

Poster Sessions

302

Diffusion: Modelling Hall D Tuesday 13:30-15:30

1777. Thalamic Nuclei Clustering on High Angular Resolution Diffusion Images Azzurra Grassi1, Leila Cammoun1, Claudio Pollo, Patric Hagmann2, Reto Meuli2, Jean Philippe Philippe Thiran1 1Signal Processing Institute, Ecole Polytechnique Federale de Lausanne, Ecublens, Switzerland; 2Centre Hospitalier Universitaire Vaudois and University of Lausanne, Switzerland

Thalamic nuclei can be distinguished by their characteristic fiber orientations, which influence the diffusion. Fiber orientations are relatively aligned within a nucleus due to the fact that the cerebrocortical striations within a nucleus all target the same region of cortex. The number of thalamic nuclei reported with histological methods varies with the method employed, although most cyto/myeloarchitectonic stains identify 14 major nuclei. We present a new approach for thalamic nuclei segmentation on High Angular Diffusion Resolution Images (HARDI), performed with a constrained k-means clustering.

1778. Application of Discrminant Principal Component Analysis to Distinguish Schizophrenic Subjects from Normal Controls Based on Fractional Anisotropy Measurements Arvind Caprihan1, Godfrey D. Pearlson2, 3, Vince D. Calhoun1, 4 1The MIND Institute, Albuquerque, USA; 2Olin Neuropsychiatry Research Center, Hartford, USA; 3Yale University, USA; 4University of New Mexico, Albuquerque, USA

In a pattern classification study the standard PCA can eliminate features that discriminate and keep features that best represent the group. We study an alternative method for selecting features which maximize the Mahalanobis distance between groups. We apply this discriminatory PCA (DPCA) to a fractional anisotropy data set from schizophrenic subjects and normal controls. We show that the choice of features can have significant impact if not done in a manner consistent with the final objective. For our data we were able to reduce the image dimensions from 149206x90 to a 60x90 matrix without any significant increase in classification error.

1779. Agreement and Disagreement Between Two Models of Diffusion MR Signal Matt G. Hall1, Daniel C. Alexander1 1University College London, London, UK

We compare two models of diffusion in white matter undergoing inflammation: an analytical model and a monte-carlo model. We use both models to synthesise diffusion-weighted signals from spins diffusing in an environment undergoing cell swelling. We find good agreement in the models until the cylinders begin to abutt and overlap, when the monte-carlo model deviates from the analytical. We infer that cylinder abutting can have measurable effect on diffusion-weighted signal.

1780. A Hexagon is a Circle Matt G. Hall1, Daniel C. Alexander1 1University College London, London, UK

We compare approximations of cylinders of circular cross-section with cylinders with regular polygonal cross-section as restricting geometries in Monte-Carlo simulations of diffusion used to generate synthetic diffusion-weighted measurements. We find that a cylinder with six facets gice a good approximation of a circular cross section. We also present preliminary results approximating a sphere with platonic solids. We find that a tetrahedron has low anisotropy.

1781. Full Tensor is Not Required to Quantify the White Matter Damage in Contusive Spinal Cord Injury Tsang-Wei Tu1, Joong Hee Kim2, Hsiao-Fang Liang2, Sheng-Kwei Song2 1Aerospace and Structural Engineering, Washington University School of Engineering, St. Louis USA, Missouri, USA; 2Washington University School of Medicine, St. Louis, Missouri, USA

SynopsisA two-direction diffusion encoding gradient scheme to derive the directional diffusivities for assessing the extent of white matter damage in a mouse model of contusive spinal cord injury (SCI) has been examined and compared with the commonly used 6-direction DTI. Comparable results have been observed in diffusion anisotropy and directional diffusivities for the control mouse spinal cords. More importantly, the extent of white matter injury estimated using 6-direction DTI was comparable with those determined by 2-direction DWI. All in vivo MRI findings were validated with immunohistochemisty. The results suggest that the full tensor analysis is not necessary to quantity the extent of white matter injury in mouse SCI. This approach offers the advantage of saving a 67 % scan time needed for the conventional six-direction DTI.

1782. Parsimonious Model Selection for DTI Tissue Segmentation and Classification Applied to Clinical Data Raisa Z. Freidlin1, 2, Evren Ozarslan1, Peter J. Basser1, Carlo Pierpaoli1 1NIH, Bethesda, USA; 2George Washington University, Washinton, District Of Columbia, USA

We used a statistical method for parsimonious model selection to choose the most appropriate water diffusion model (isotropic, oblate, prolate, or general anisotropic) for in vivo DTI of the human brain. We found that the prolate model reliably identifies structures with orientationally coherent fibers (e.g., the mid sections of the corpus callosum). However, most white matter regions are identified by the general anisotropic model, suggesting that their underlying fiber architecture is consistent with multiple fiber population within a voxel. The information provided by this method may be useful for optimal experimental design of diffusion MRI experiments and for selecting approaches to data analysis.

1783. The Elliptical Cone of Uncertainty in Diffusion Tensor Imaging and Its Normalized Measures Cheng Guan Koay1, Peter J. Basser1 1National Institutes of Health, Bethesda, Maryland, USA

This study presents a technique of constructing the cone of uncertainty (COU) of the major eigenvector of the diffusion tensor based on the inverse of the Gnomonic projection, and two normalized geometric measures associated with the COU—the normalized areal and circumferential measures. These measures are local coherence measures for quantifying tract dispersion. The proposed measures, which are directly linked to the uncertainty in the major eigenvector of the diffusion tensor, may be important for probing the integrity of the white matter tracts in the brain and for DT-MRI tractography.

Poster Sessions

303

1784. Diffusivity in the Brain White Matter: Application of the Recursive Effective Medium Approximation Oleg Petrovich Posnansky1, Nadim Jon Shah1 1Institute of Neurosciences and Biophysics (Medicine), Research Centre Juelich, Juelich, Germany

In order to explore the effects of a large range of geometrical and physical structural microparameters on the effective apparent diffusion coefficient we have developed a recursive effective medium approximation. The key point of this approximation consists in step-by-step averaging from the micro to the millimeter scale of the strongly fluctuating effective diffusivity. Such an approach provides insight into the fundamental of the diffusive process in a very random and heterogeneous structure of brain white matter and allows quantification of the sensitivity of the apparent diffusion coefficient to the variations of the different microparameters.

1785. Ellipsoidal Area Ratio (EAR): An Alternative Anisotropy Index for Diffusion Tensor Imaging Dongrong Xu1, 2, Jiali Cui1, Peterson S. Bradley1, 2 1Columbia University, New York, New York, USA; 2New York State Psychiatric Institute, New York, New York, USA

Diffusion Anisotropy Index (DAI) is a scalar measure of diffusion tensor imaging data, and Fractional Anisotropy (FA) is the most popular one. However, FA is sensitive to noise and is not directly linked to the intuitive interpretation of a tensor¡¯s morphology. We have developed a novel DAI, called Ellipsoidal Area Ratio(EAR), that offers higher signal-to-noise ratios and maintain similar contrast-to-noise ratios.

1786. Dynamic Diffusion Analysis of Chitosan-Based Hydrogels Using Magnetic Resonance Richard Wong1, Chih-Chang Chu, 12, Chao Zhong1, Yi Wang1, 3 1Cornell University, Ithaca, New York, USA; 2Cornell Unversity, Ithaca, New York, USA; 3Weill Medical College of Cornell University, New York, New York, USA

This study identifies three major metrics of hydrogel design and analyzes a chitosan-based family of hydrogels using MR techniques. Results demonstrate the behavioral variability that can be achieved by altering a hydrogel’s composition and illustrates to use of MR in synthesizing metric-based hydrogels.

Diffusion-Biophysics Hall D Wednesday 13:30-15:30

1787. Change in Water Diffusion Properties with Altered Muscle Architecture Anneriet M. Heemskerk1, 2, Tuhin K. Sinha1, Kevin J. Wilson1, Bruce M. Damon1 1Vanderbilt University, Nashville, Tennessee, USA

For skeletal muscle λ2 and λ3 are perpendicular to the fiber direction and previous studies suggest that they have different structural origins. The goal of this study was to determine whether and how the DTI indices change upon muscle lengthening. Ten subjects were studied with their foot in two different positions and twice in the same position. The latter showed reproducible DTI values. However, the second eigenvalue decreased with increased foot rotation, whereas the other indices remain constant. This confirms that the λ 2 and λ3 have different structural origins.

1788. The Role of Surface Relaxivity and Magnetic Susceptibility in the Design of Anisotropic Fiber Phantoms Els Fieremans1, Chi Chen1, Yves De Deene2, Eric Achten3, Ignace Lemahieu1 1Ghent University, Ghent, Belgium; 2Ghent University Hospital, Ghent, Belgium; 3Ghent University Hospital, Belgium

Anisotropic fiber phantoms have been proposed for the validation of DTI on clinical MR-scanners and to test fiber tracking algorithms, particularly in the case of fiber crossings. Several fiber materials have been used: rayon, Dyneema®, hemp, linen, acrylic fibers, rayon, acrylic fiber, … Choosing the appropriate fiber material requires insight in the factors influencing the diffusion and the signal-to-noise ratio. This study enumerates the different parameters (fiber diameter, fiber density, surface relaxivity and susceptibility differences) and their impact in the resulting diffusion properties and T2.

1789. Voxel-Based Correlation Analysis Between Diffusion Anisotropy Measures and Myelin Content in Human Brain Burkhard Mädler1, 2, Shannon H. Kolind2, Alex L. MacKay2 1Philips Medical Systems, Vancouver, Canada; 2University of British Columbia, Vancouver, Canada

We compare T2-relaxation data and diffusion tensor data from normal human brain. The relationships between myelin water fraction (MWF) and various diffusion tensor measures in white and grey matter structures in the brain were examined in 6 normal subjects at 3.0T. We found some degree of linear correlation between these measurements, but by using ROI-based analysis we also observed several structures which seemed to deviate significantly from a linear relationship. From all investigated relationships between various diffusion tensor measures and myelin-water content, fractional anisotropy (FA) and perpendicular diffusivity (ADCperp) yielded the highest correlation coefficients with MWF. However, diffusion anisotropy was also significantly influenced by factors other than myelin water content. The less operator dependent voxel-based analysis between myelin-water and diffusional anisotropy measures is proposed as an innovative alternative to ROI-based analysis.

1790. Investigation of Bi-Exponential Diffusion in Treated Brain Tumors Benjamin Alan Hoff1, Denis Le Bihan2, Alnawaz Rehemtulla1, Thomas L. Chenevert1, Brian D. Ross1, Craig J. Galban1 1University of Michigan, Ann Arbor, Michigan, USA; 2NeuroSpin, CEA, Saclay, France

The purpose of this study was to investigate bi-exponential diffusion of water in a brain tumor following therapeutic treatment. Diffusion-weighted images at 17 different b-values were acquired in a 9L glioma rat model. Both fast and slow diffusion coefficients were found to peak significantly by day 6 of treatment, whereas the fast diffusion fraction in the bi-exponential fit peaked at day 9. We found that the fast diffusion coefficient was the most sensitive to therapy, indicating that the therapeutic response not only involves a shift in the relative fractional volume, but also the actual diffusion rates.

Poster Sessions

304

1791. On the Effects of a Varied Diffusion Time in Vivo: is the Diffusion in White Matter Restricted? Markus Nilsson1, Jimmt Lätt1, Emil Nordh1, Ronnie Wirestam1, Freddy Ståhlberg1, Sara Brockstedt1 1Lund University, Lund, Sweden

The signal-vs-b curve was measured perpendicular to the corticospinal tract in vivo to determine whether effects of restricted diffusion could be observed when varying the diffusion time between 64 and 256 ms and sampling b-values up to 86 000 s/mm2. Restricted diffusion with exchange was simulated for equally sized cylinders. The measurements showed no effects of restriction perpendicular to the tract. Comparisons of the signal-vs-b curves from the measurements with the simulations further indicated that no effects of restricted diffusion could be observed perpendicular to the tract.

1792. Probing Intracellular Compartments in Normal Brain and Brain Tumor Using Short Diffusion Times Douglas Edward Prah1, Eric Scott Paulson1, Melissa L. Wagner-Schuman1, Kathleen M. Schmainda1 1Medical College of Wisconsin, Milwaukee, Wisconsin, USA

Standard imaging techniques inadequately detect tumor cell invasion. Often the failure of surgical resection and radiation therapy, the primary treatments for gliomas, are attributed to tumor invasion. Treatment outcome may improve if more localized therapies are prescribed to areas of invasion. Results from this study demonstrate that diffusion data acquired at short diffusion times, may be more sensitive to the tissue/tumor intracellular environment, and therefore may be able to detect invading tumor cells.

1793. Diffusional Restrictivity: Looking at the Slow Water Mariana Lazar1, Jens H. Jensen1, Joseph A. Helpern1 1New York University School of Medicine, New York, USA

In this abstract we introduce a new metric, the diffusional restrictivity (RD), which primarily depicts contributions from shorter diffusion paths. As a result, RD is more sensitive to restricted water compartments and smaller scale structures and less prone to partial volume averaging effects from the fast water compartments (such as CSF contamination). Thus, it should provide a more robust marker of the tissue microstructure. RD can be decomposed into Gaussian and non-Gaussian components. Restrictivity maps for human brain diffusion data show significant white matter/gray matter contrast with higher restrictivity being observed in white matter.

1794. A Realistic DTI Simulation Environment Gregory T. Balls1, Lawrence R. Frank1 1University of California, San Diego, La Jolla, California , USA

Simulations of diffusion in neural tissues have traditionally been limited to analytical solutions or to grid-based solvers unable to simulate realistic complex neural tissues. We have built a simulation environment that combines a Monte Carlo Brownian dynamics simulator with a MR signal generator. The Monte Carlo simulator is capable of simulating diffusion in arbitrarily complex polygonal geometries and modeling chemical reactions and relaxation. The signal generator is flexible enough to handle a variety of pulse sequences. We demonstrate results for aligned and crossing straight fibers, varying fiber packing density and permeability.

1795. Multiexponential Diffusion Measurements of Varying Densities of Astrocytoma Cells Pamela R. Jackson1, Roland G. Henry2, Tracy R. McKnight2 1University of California, Berkeley and San Francisco, San Francisco, California , USA; 2University of California, San Francisco, San Francisco, California , USA

To better understand how cell density affects diffusion, we suspended different densities of cells (0%, 25%, 50%, 75%, and 100%) in agarose and measured diffusion using 32 b values. Monoexponential, biexponential, and non negative least squares algorithms were used to fit the data, and the Spearman Rank test was used to test correlation . The monoexponential decrease in diffusion with increasing cell density was dominated the fast diffusion component. The faster diffusion component appeared to be associated with agar presence and the slower component may have been associated with the cells.

1796. Effects of Water Exchange: a High B-Value Diffusion Study of Ischemic Stroke Lesions in the Human Brain Jimmy Lätt1, Markus Nilsson1, Danielle van Westen1, Ronnie Wirestam1, Fredrik Örtendahl1, Freddy Ståhlberg1, Stig Holtås1, Sara Brockstedt1 1Clinical Sciences Lund University, Lund, Sweden

Diffusion weighted imaging (DWI) enables visualization of ischemic stroke in the acute phase. However, the underlying reasons for the altered signal characteristics of the ischemic lesion are still under debate. In this preliminary study, measurements at different diffusion times were performed, potentially providing information about the tissue microstructure, with respect to restricted diffusion and exchange mechanisms.

1797. Diffusion-Weighted Signal in White Matter: What is Behind the B-Factor Dependence? Valerij G. Kiselev1, Kamil A. Il'yasov2 1University Hospital Freiburg, Freiburg, Germany; 2Kazan State University, Kazan, Russian Federation

Diffusion weighted signal can be characterised via an infinite set of coefficients of the expansion in b-factor. In practice, the number of detectable coefficients is restricted by the noise. This description is examined in the corpus callosum. It is shown that only two coefficient can be found using b-factors up to 2500 mm^2/s. Those are the diffusion coefficient and the kurtosis excess. This means that the contributions of the intra- and extra-axonal compartments cannot be recognised in the total signal. The discussion focuses on constraints this result imposes on the currently unknown diffusion parameters in extra-axonal space.

Poster Sessions

305

Diffusion Acquisition Hall D Thursday 13:30-15:30

1798. Effects of T2-Weighting on Optimum b-Value vs. SNR for ADC Measurements Emine Ulku Saritas1, Jin Hyung Lee1, Dwight G. Nishimura1 1Stanford University, Stanford, California , USA

The optimization of b-value for two-point apparent diffusion coefficient (ADC) estimation schemes were previously investigated, assuming high signal-to-noise ratio (SNR) imaging and considering the effects of T2-weighting. Here, we investigate both the dependence of the optimum b-value on the SNR of the imaging scheme and also on the T2 of the tissue of interest. The results of this work are especially important for high-resolution diffusion-weighted imaging, which intrinsically suffers from low SNR.

1799. Investigation of the Effects of Quality Weighting in Turboprop-DTI on the Diffusion Tensor Noise Due to Brain Pulsation Minzhi Gui1, Zhe Hu1, Konstantinos Arfanakis1 1Illinois Institute of Technology, Chicago, Illinois, USA

In the image reconstruction process for Turboprop diffusion tensor imaging (DTI), weights representing the quality of the data are estimated for each k-space blade (quality weighting, QW), and used during reconstruction to reduce the contribution of corrupted blades to the final image. This weighting procedure reduces artifacts due to: bulk motion, odd/even echo fluctuations, and other sources of k-space data variation between blades. In this work, the degree to which the QW also compensates for the increase in the total variance of the diffusion tensor due to cardiac-induced brain pulsation is investigated in both simulations and experiments on humans.

1800. Evaluation of Spatial Normalization in Turboprop-DTI vs. SE-EPI-DTI Huiling Peng1, Gady Agam1, Minzhi Gui1, Konstantinos Arfanakis1 1Illinois Institute of Technology, Chicago, USA

Accurate spatial normalization in diffusion tensor imaging (DTI) requires data with minimal artifacts. Conventional spin-echo echo-planar DTI (SE-EPI-DTI) suffers from severe B0-related image artifacts, which are prominent in certain brain regions, such as the brainstem, the frontal and temporal lobes. In contrast, Turboprop-DTI is relatively immune to image artifacts caused by magnetic field inhomogeneities. In this study, the performance of spatial normalization of DTI data obtained with SE-EPI-DTI and Turboprop-DTI was evaluated. The results demonstrated that, Turboprop-DTI may lead to more accurate spatial normalization than SE-EPI-DTI in regions where the latter suffers from magnetic field inhomogeneity artifacts.

1801. Improvement of Diffusion Weighted Images with Reduced-View Radial Acquisitions Yeji Han1, JinYoung Hwang2, HyunWook Park2 1University Hospital Freiburg, Freiburg, Germany; 2Korea Advanced Institute of Science and Technology, Republic of Korea

The proposed method aims to generate high-resolution diffusion-weighted (DW) images from a reduced number of projection data acquired with any kind of existing radial acquisition sequences. After acquiring less than a half of the required number of projection data, a reasonable estimation of the unacquired part of the projections is performed. After that, the proposed process refines the estimated projection data utilizing information of a full-resolution non-DW image. By using the proposed method, the acquisition time can be decreased while preserving the image quality. The simulation and experiment results show that the proposed method gives high-resolution DW images from the reduced-view projection dataset.

1802. 3T PROPELLER DiffusionTensor Imaging and Tractography : A Method for SAR Reduction Hiroyuki Kabasawa1, Shigeki Aoki2, Yoshitaka Masutani2, Osamu Abe2, Kuni Ohtomo2 1GE Yokogawa Medical Systems, Hino-shi, Japan; 2The university of Tokyo, Bunkyo-ku, Japan

We demonstrated that VERSE implementation to PROPELLER reduced SAR and that helped to increase volume coverage and reduce scan time to clinically acceptable range. Slice coverage was increased from less than slice to 28 slices with 8sec of repetition time. The proposed method has potential for acquiring diffusion tensor images without compromising both image geometry accuracy and slice coverage.

1803. SNR Improvement and Reduction of Geometric Distortion in 3D SingleShot Diffusion-Weighted STimulated-EPI (3D Ss-DWSTEPI) Xianfeng SHI1, Eugene Kholmovski1, Eun-Kee Jeong1 1University of Utah, Salt Lake City, USA

3D single-shot Diffusion-Weighted STimulated-EPI (3D ss-DWSTEPI) suffers from low SNR because it uses only half the diffusion-weighted magnetization stored into the longitudinal plane by a 90o RF and spoils another half. The degree of susceptibility-induced distortion in EPI-type acquisitions is inversely proportional to the speed of the k-space traveling in phase-encoding direction. To improve SNR and reduce the susceptibility-induced distortion, 3D ss-DWSTEPI in-plane readout is shorten by reducing FOV in phase-encoding direction. Parallel imaging technique has been implemented in 3D ss-DWSTEPI to reduce the geometric distortion and a method has been developed to improve SNR by utilizing whole diffusion-weighted magnetization.

1804. Diffusion Weighted Fast Spin Echo PROPELLER at 9.4T Irvin Teh1, 2, David J. Larkman1, Xavier Golay2, 3 1Imperial College London, London, UK; 2Singapore Bioimaging Consortium, Singapore, Singapore; 3National Neuroscience Institute, Singapore

Diffusion weighted imaging is widely used for studying tissue integrity and structure. Single shot DW-EPI is commonly used to improve motion robustness and efficiency, but suffers from lower resolution and magnetic field inhomogeneity effects. At high fields, image distortion and short T2* make multishot FSE methods more attractive. Periodically Rotated Overlapping ParallEL Lines with Enhanced Reconstruction (PROPELLER) has been demonstrated in humans as a self navigating and efficient sequence robust to motion artifacts and image distortion. Here, we present the novel application of DW-FSE-PROPELLER in in-vivo imaging of mice at 9.4T.

Poster Sessions

306

1805. K-Space Weighted Multi-Channel Regularization for Motion Correction in Multi-Shot DWI Sheng Fang1, Kui Ying1 1Tsinghua University, Beijing, People's Republic of China

Multi-shot diffusion-weighted imaging suffers from motion-induced phase error that varies from shot to shot. Conjugate-gradient (CG) based reconstruction may not adequately correct this error if phase estimation is not accurate enough. Besides, the CG algorithm only utilizes the phase information from the navigator image. In this work, we propose an effective k-space weighted multi-channel regularization algorithm based on Tikhonov regularization to fully utilize acquired navigator data and further reduce the residual motion-induced aliasing artifacts left by standard Tikhonov regularization. Both single-coil and multi-coil simulations have been performed to demonstrate the feasibility of the proposed method.

1806. Multi-Slice High Resolution Cerebellum Diffusion Tensor Imaging Using Pre-IR Inner Volume Excitation Tzu-Cheng Chao1, Yi-Jui Liu2, Teng-Yi Huang3, Hsiao-Wen Chung1, Cheng-Yu Sandy Chen4 1National Taiwan University, Taipei, Taiwan; 2Feng-Chia University, Taichung, Taiwan; 3National Taiwan University of Science and Technology, Taipei, Taiwan; 4Tri-Service General Hospital, Taipei, Taiwan

Susceptibility-induced geometric distortions in diffusion tensor EPI limit the image resolution in regions showing strongly inhomogeneous magnetic fields. In this work, we proposed an alternative inner volume excitation scheme for EPI with reduced FOV, which employed a pre-inversion approach suitable for multi-slice acquisition without severe compromise in SNR. Simulations and experimental results for diffusion tensor imaging in the cerebellum showed that this approach could provide simultaneous signal uniformity and good SNR throughout all slices. Susceptibility-related distortions were effectively minimized via a shortening of the data acquisition window to achieved DTI of the cerebellum at 0.86mm in-plane resolution.

1807. Comparison of Sequences for Improved Diffusion Weighted Imaging at 7 T Paul S. Morgan1, Ron J. Coxon1, Josef Habib1, Penny A. Gowland1, Richard Bowtell1 1University of Nottingham, Nottingham, UK

Application of diffusion-weighted (DW) MRI on a 7 T scanner holds the promise of significantly increased spatial resolution. However the challenges involved in implementing DW-EPI at 7 T require re-evaluation of the best sequence for obtaining DW images. Here we have therefore implemented four different DW-EPI sequences at 7 T and compared the results in terms of signal-to-noise and spatial distortion, as well as studying the effect of parallel imaging. Twice-refocused DW-EPI acquisitions were found to offer the best compromise between SNR and spatial distortion.

1808. Comparison of Short-Readout Trajectories for Diffusion-Weighted Imaging Samantha J. Holdsworth1, Stefan Skare1, Rexford D. Newbould1, Anders Nordell2, Roland Bammer1 1Stanford University, Palo Alto, California , USA; 2Karolinska University Hospital, Stockholm, Sweden

“Short-Axis readout Propeller EPI” (SAP-EPI), its dual-blade variant (dual-blade SAP-EPI), and Readout-Segmented EPI (RS-EPI) have been proposed as variants of EPI for high resolution diffusion-weighted (DW) imaging. While there are many similarities between these sequences, there are various differences between them which affect the scan efficiency and overall image quality. The purpose of this abstract is to make an initial assessment of these schemes with regard to diffusion preparation/acquisition ratio, normalized scan time, and image quality for a typical set of scan parameters we have been using for high resolution GRAPPA-accelerated DW imaging.

1809. Non-Uniform Distribution of Diffusion Gradient Directions Using Preferred Diffusion Tensor Orientations in the Human Brain Jeroen Siero1, Hans Hoogduin1 1University Medical Center Groningen / University of Groningen, Groningen, Netherlands

A non-uniform gradient direction scheme for DTI is presented based on the non-uniform fiber orientations in the human brain. A comparison with a uniform 60 direction scheme shows an increase in FA values and a decreased error for the dominant fiber directions.

1810. On the Utility of Complex-Averaged Diffusion-Weighted Images Rexford David Newbould1, Stefan Skare1, Roland Bammer1 1Stanford University, Stanford, California , USA

Magnitude averaging is very common in diffusion imaging, as it avoids random phase offsets in the data from the diffusion-sensitizing gradients. Noise in magnitude MR images is Rician distributed. In low SNR magnitude images, such as diffusion images, the Rician distribution approaches a Rayleigh distribution. This introduces a severe non-zero bias of the signal expectation value and underestimates the calculated ADC. The deflection of the diffusion attenuation can reduce the CNR and mimic biexponential decay. Combining magnitude diffusion images for signal averaging or to create isotropic DWI images does not lower this mean, whereas combining complex diffusion images does.

1811. High Angular Resolution Diffusion Imaging with B0 Distortion Correction at 7T Ha-Kyu Jeong1, 2, Adam W. Anderson1 1Vanderbilt University, Nashville, Tennessee, USA

In this study, high angular resolution diffusion imaging (HARDI) measurements performed at 7T were corrected for distortions due to B0 field inhomogeneities using a static field map. After the correction, the anatomy of individual brain slices and corresponding fiber tracts are much closer to those of multishot gradient echo images, which have relatively small distortions. The improvements in spatial accuracy of the HARDI data are critical for quantitative applications of diffusion MRI at high field strengths.

1812. In Vivo Human Brain Diffusion Tensor Imaging (DTI) at 3T and 7 T Ralf Luetzkendorf1, Tobias Moench1, Maurice Hollmann1, Sebastian Baecke1, Claus Tempelmann1, Joerg Stadler2, Johannes Bernarding1 1University of Magdeburg, Magdeburg, Germany; 2Leibniz Institute for Neurobiology, Magdeburg, Germany

Higher B0 fields are expected to increase the signal-to-noise ratio which should lead to higher spatial resolution of DTI. At high fields B1 inhomogeneities are strong and result in sever distortions and signal voids in DTI. We used parallel imaging techniques combined with data post-processing to reduce distortions and to reach a high spatial resolution. The same starting maps and waypoint maps to track the apparent fibers of the same volunteer were used in both 3T and 7T to ensure the comparability of the data.

Poster Sessions

307

1813. Fast Fluid Suppressed DTI Allen W. Song1, Zoe Englander1, Bin Chen1 1Duke University, Durham, North Carolina, USA

DTI images suffer from fluid contaminations from CSF and vasculature, especially in the ventral brain regions, periventricular space and cortical surface, because of the hyper-intensity of fluid in the T2 weighted baseline image. Early methods for removing these confounds have relied on inversion recovery technique which could result in a large reduction in signal-to-noise ratio and temporal resolution. Here we propose a method that applies flow-sensitive diffusion weighting to the baseline scan, and evaluate its advantage on improving the delineation of white matter anisotropy. Much improved characterization of white matter anisotropy is found with further separation from the gray matter.

1814. Compressed Sensing in Diffusion-Weighted Radial-FSE Ted P. Trouard1, 2, John Wade Totenhagen1, Ali Bilgin1 1University of Arizona, Tucson, Arizona , USA

Compressed Sensing (CS) reconstruction enables generation of images from dramatically undersampled MRI data. In this work, CS methodology is applied to undersampled diffusion-weighted radial-FSE datasets to evaluate the utility of CS to reduce scan times in multishot DW-radial-FSE acquisitions. DW-radial-FSE has been shown to produce diffusion-weighted images with high spatial resolution and little artifact from motion and/or magnetic field inhomogeneities, but requires considerably more acquisition time than single-shot DW-MRI methods. CS reconstruction of severely undersampled radial-FSE data is shown to produce diffusion-weighted images and ADC maps without the streaking artifacts generated by filtered backprojection or regridding reconstruction.

1815. In Vivo Diffusion Tensor Imaging of Human Optic Nerve Using 2D Interleaved Inner Volume Technique on 3T System Seong-Eun Kim1, Eun-Kee Jeong1, Tae Ho Kim1, J Rock Hadley1, Emilee Minagla1, Jeff Anderson1, Dennis L. Parker1 1University of Utah, Salt Lake City, USA

In this work we present the in vivo DTI measurement of the normal human optic nerve using two different interleaved multiple inner volume diffusion weighted EPI sequences and a 20 channel dedicated optic nerve coil on 3T system. The results indicate that both 2D IMIV-DWEPI and 2D rFOV-DWEPI allow reliable DTI measurement of optic nerve and ocular muscle. Quantitative analysis of diffusivity and anisotropy in the human optic nerve area appears to be feasible and has potential to enable more sensitive and specific detection and monitoring of structural changes caused by pathology including multiple sclerosis, optic neuritis, and neurofibromatosis.

1816. A Simple But Robust Isotropic and Background Gradient Independent Diffusion Gradient Design Hua Guo1, 2, Allen W. Song2, Ed X. Wu1 1The University of Hong Kong, Pokfulam, Hong Kong; 2Duke University, Durham, North Carolina, USA

Due to computation and design complexity, there is no design so far for isotropic and background gradient independent diffusion gradients. In this abstract, we present a simple but robust method to design orientation invariant and background magnetic field insensitive diffusion gradients. Although the diffusion weighting efficiency is reduced, this design provides a set of diffusion gradients that may be used to map ADC efficiently and accurately or in presence of severe field inhomogeneity such as induced by metal implants.

1817. DTI of the Human Brain with Sub-Millimeter Voxel Size: Clear Depiction of Fiber Decussation in the Optic Chiasm Joelle E. Sarlls1, Stefano Marenco1, Carlo Pierpaoli1 1National Institutes of Health, Bethesda, Maryland, USA

Sub-millimeter isotropic voxel diffusion tensor images (DTI) of the optic chiasm are presented, in vivo, for the first time. Data are acquired with a modified radial-FSE sequence, which allows anatomical details of structures in the brain to be studied with a voxel size about 10 times smaller than that currently achievable with EPI-based DTI. These images clearly depict the decussation of the medial fibers in the optic chiasm. Geometric distortion and susceptibility artifacts are virtually eliminated in these high-resolution DTI maps.

Diffusion: Artifacts, Phantoms, QA, Reproducibility Hall D Monday 14:00-16:00

1818. Testing the Reproducibility of Diffusion Tensor Imaging at 3.0T Jesper Frandsen1, Leif Østergaard1, Eva B. Vedel Jensen2 1Aarhus University Hospital, Aarhus C, Denmark; 2Aarhus University, Aarhus C, Denmark

From Diffusion Tensor Imaging (DTI) scalar indices such as apparent diffusion coefficient (ADC) and fractional anisotropy (FA) can be extracted. This indices are often used for comparing groups of healthy controls to groups with neurodegenerative deceases. In this study we have performed DTI on the same subject 20 times within few days to examine the reproducibility of these indices on a 3.0T scanner.

1819. Quantitative Evaluation of Diffusion Weighted-MRI Phantoms Wilhelmus LPM Pullens1, 2, Alard Roebroeck3, Rainer Goebel3 1Maastricht University, Maastricht, Netherlands; 2Brain Innovation BV, Maastricht, Netherlands; 3Maastricht University, Netherlands

This paper presents phantoms for qualitative and quantitative validation of diffusion weighted MRI and fiber tracking. The aim is to construct a phantom with properties (T2 and anisotropy) similar to human white matter , combined with the possibility to create different geometries, to be measured with clinical protocols. Phantoms show higher perpendicular versus parallel ADC, as well as exponential signal decay when b-value is increased. FA is in a similar range as FA in human white matter. The phantom can be used for validation of fiber tracking; the construction method is suitable for crossing or kissing geometries at various angles.

Poster Sessions

308

1820. Effects of Motion on Clinical Diffusion Tensor Imaging Rob Hendrikus Tijssen1, Jacobus F. Jansen2, Walter H. Backes2 1Eindhoven University of Technology, Eindhoven, Netherlands; 2Maastricht University Hospital, Maastricht, Netherlands

In DTI, the gradient sampling scheme affects the propagation of image noise. Various optimized schemes have been proposed. However, these schemes are not immediately available in a clinical setting. Additionally, subject motion may have a considerable effect. This work assesses six clinically available gradient schemes by in vivo analyses and computer simulations. Our data show that, like image noise, motion effects are dependent on the sampling scheme. Whereas schemes with medium and high angular resolution showed similar results, gradient schemes with only six gradient directions demonstrated a considerably lower reproducibility and incur positive bias in the presence of motion.

1821. Interpolation and Regularization of Diffusion Tensors Along Geodesics Jaime E. Cisternas1, Marcelo Gálvez2, Gonzalo Rojas2, Takeshi Asahi2 1Universidad de los Andes, Santiago, Chile; 2Universidad de Chile, Santiago, Chile

The processing of diffusion tensor imaging (DTI) and tractography involve a number of steps, such as the registration, the estimation and the smoothing of tensor fields. These procedures implicitly rely on a measure to compare two or more tensors as well as on a continuous transformation of tensors.Several strategies for measuring distances between tensors have been proposed, some of them inspired from sophisticated mathematics and some others aiming at fast computations. Here we propose a simple theoretical framework to separate the problem into two parts: the first considers the shape of tensors, and the second their orientation. We illustrate the application of the interpolation and the regularization methods built from such a distance using a synthetic example and a DTI scan from a fiber phantom.

1822. Towards a Diffusion Standard Ruler: Rigid Diffusion Phantom Koji Sakai1, 2, Takashi Azuma1, Susum Mori2, Koji Koyamada1, Sadami Tsutsumi1 1Kyoto University, Kyoto, Japan; 2Johns Hopkins University, Baltimore, Maryland, USA

Anisotropy phantom for DTI studies is much needed for calibration of multi-center studies. Ideally, we can control the degree of anisotropy and the phantom is stable and mass-producible. In this paper, we introduce a DTI phantom based on channeled silicon plates. We demonstrate that the water diffusivity and anisotropy can be controlled by changing the channel depth and the anisotropy can be as high as 0.8. Interestingly, we observed axial diffusivity higher than free diffusion, posing us an interesting question about the interpretation of DTI results. Quality control for the production is a current issue to make this phantom available.

1823. The Impact of Robust Tensor Estimation on Voxel-Wise Analysis of DTI Data Daniel Jon Peterson1, Bennett A. Landman2, Laurie E. Cutting1, 2 1Kennedy Krieger Institute, Baltimore, Maryland, USA; 2Johns Hopkins School of Medicine, Baltimore, Maryland, USA

Methods of robust diffusion tensor estimation, like RESTORE, have been shown to decrease the effect of artifacts in a single subject. Here we demonstrate the impact of RESTORE on a voxel-wise group analysis of DTI data, using Cerebellar Ataxia as a sample condition. In a voxel-wise statistical comparison of the difference in FA between controls and patients, RESTORE was found to decrease the number of small areas of significance that are likely to be spurious. Additionally, a high number of outliers were found in regions vulnerable to artifacts, and RESTORE was shown to alter FA in a spatially heterogeneous manner

1824. How Reliable Are Diffusion Tensor Spectroscopy Measures of Metabolite Diffusion? Jacob Ellegood1, Chris C. Hanstock1, Christian Beaulieu1 1University of Alberta, Edmonton, Canada

Diffusion tensor spectroscopy (DTS) of metabolites in human brain could provide novel information, but it is challenging given low apparent diffusion coefficients (ADC) and poor signal-to-noise. Too much variability in measured ADC with diffusion gradient direction could artificially inflate fractional anisotropy (FA) values, particularly at low ADC, and make isotropic regions appear anisotropic. More accurate measurements could result from the use of higher b values (5000 s/mm2) than that more commonly used in DTS (1500-2000 s/mm2). The sensitivity of FA was shown to be true for a range of isotropic alcohols with low ADC and in human occipital gray matter.

1825. Non-Linearity in Diffusion-Gradient Induced Eddy-Current Fields in a Head Only 3T Scanner Pablo Velasco1, Souheil J. Inati1 1NYU, New York, New York, USA

We investigated the linearity of the eddy-current induced fields in diffusion-weighted imaging in a head-only 3T scanner. We find that the short-time eddy-current fields scale with the amplitude of the diffusion gradients, but the long-time eddy-current induced fields do not. This non-linearity implies that a full characterization of the spatio-temporal distribution of the field is needed for optimal image quality in DWI.

1826. Employing Bootstrapping Methods to Examine the Need for Pulse Triggering in Diffusion-Weighted Imaging Zoltan Nagy1, Chloe Hutton1, Daniel C. Alexander1, Ralf Deichmann1, 2, Nikolaus Weiskopf1 1University College London, London, UK; 2University of Frankfurt, Frankfurt, Germany

Employing pulse triggering is in wide-spread use for diffusion weighted imaging since the demonstration that this reduces image variance. However, gradient systems have improved in speed/strength and parallel imaging methods have further reduced the acquisition time. We employed bootstrapping statistical methods to establish whether pulse triggering reduces the variance in diffusion-weighted datasets acquired using recent gradient systems. To this effect we found no significant advantage resulting from the use of pulse triggering. This offers the possibility for a significant reduction in acquisition time or the chance for multiple acquisitions but should be determined individually for each scanner/site/patient group.

Poster Sessions

309

1827. Robust Diffusion Tensor Estimation by Maximizing Rician Likelihood Bennett Allan Landman1, Pierre-Louis Bazin1, Jerry L. Prince1 1Johns Hopkins University, Baltimore, Maryland, USA

Maximum likelihood tensor estimation based on a full treatment of Rician distributed MR intensities (DTEMRL) has been recently shown to significantly improve DTI reliability in clinical and high SNR applications. However, DTEMRL suffers from low reliability in low SNR applications. Here, we present a robust maximum a posteriori generalization (rDTEMRL) of the DTEMRL technique by inclusion of noise level Bayesian priors and a robust likelihood function. In simulation, the new method is shown to offer superior reliability and robust performance in the presence of artifact. In an empirical study, rDTERML improves the consistency of diffusion tensor estimates.

1828. Dealing with Artifacts Induced by Spike Noise in Diffusion Tensor Imaging Jonathan S. Jackson1, Elvina M. Chu1, Mara Cercignani2, Maria A. Ron1, Claudia A. Wheeler-Kingshott1 1UCL Institute of Neurology, London, UK; 2Fondazione Santa Lucia, Rome, Italy

DTI data can be affected by many types of artifact. In a case where one out of 68 diffusion weighted images was affected by spike noise, the FA map showed an artifactual 5% variation in white matter, which is of the order of changes induced by pathology. The effect of this artifact can be removed through a combination of manual editing and the RESTORE algorithm proposed by Chang et al. (2005).

1829. Comparison of EPI Distortion Correction Methods in Diffusion Tensor MRI Minjie Wu1, 2, Alan S. Barnett1, Stefano Marenco1, Lindsay Walker1, Herve Lemaitre1, Carlo Pierpaoli1 1National Institutes of Health, Bethesda, Maryland, USA; 2University of Pittsburgh, Pittsburgh, Pennsylvania, USA

EPI distortions in diffusion-weighted images (DWIs) degrade the quality of brain DT-MRI. In this study, we evaluate the performance of two methods for correcting EPI distortions: the standard method based on B0 field mapping (B0M) and a newly proposed b-spline image registration method (BSP). We found that both methods can effectively reduce the EPI geometric distortion improving the anatomical accuracy of quantities derived from the diffusion tensor. However, the BSP algorithm consistently provides better correction for rostral brain regions while the B0M method performs better at the base of the brain, including temporal lobes, brainstem, and cerebellum.

1830. Robust DTI Noise Level Estimation Improves RESTORE Tensor Estimation Bennett Allan Landman1, Pierre-Louis Bazin1, Jerry L. Prince1 1Johns Hopkins University, Baltimore, Maryland, USA

We present a noise level estimation method that specifically addresses the challenges of diffusion tensor imaging (DTI) data. Our method utilizes two repeated DTI acquisitions, which are commonly acquired in clinical DTI protocols, to identify the spatially varying noise profile. The novel noise level estimates significantly improve accuracy of the RESTORE tensor estimation method when compared with conventional noise level estimation approaches. This method is robust to background signal suppression, spatial noise correlation, and coil sensitivity variability.

Fiber Tracking & Connectivity Mapping Hall D Tuesday 13:30-15:30

1831. Exploiting the Fibre-Orientation Distribution for Probabilistic Tractography Kiran Kumar Seunarine1, Shahrum Nedjati-Gilani1, Matt G. Hall1, Philip A. Cook2, Daniel C. Alexander1 1University College London, London, UK; 2University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA

Probabilistic tractography generates a map of connectivity of each voxel to a specified seed voxel, and typically use models of the uncertainty in each fibre-orientation estimate to provide fibre-direction samples for multiple repeats of the streamline tractography process. The assumption is that these uncertainty models reflect the true underlying distribution of fibre-orientations in each voxel, but may differ significantly in practice. We present an initial study into using the actual fibre-orientation distribution directly. Our method generates a calibration procedure to learn a mapping between features of the diffusion tensor and the fibre-orientation distribution and use that for probabilistic tractography.

1832. Combining Spherical Deconvolution and Streamline Tractography : Preliminary Results Flavio Dell'Acqua1, 2, Paola Scifo1, Marco Catani2, Giuseppe Scotti1, Ferruccio Fazio1 1San Raffaele Scientific Institute, Milan, Italy; 2Institute of Psychiatry, London, UK

In this study, we combined a simple streamline tractography method with a modified damped Richardson-Lucy spherical deconvolution algorithm to perform dissections of white matter pathways in a complex brain region with several crossing fibers. Preliminary results on in-vivo data are shown.

1833. White Matter Tract Visualisation Using a Parabolic Eigensystem Thomas Richard Barrick1, Nigel Lawes1, Chris A. Clark2 1Saint George's, University of London, London, UK; 2University College London, London, UK

Here we present a method for visual segmentation of tracts by interrogation of streamline termination coordinates and invocation of a parabolic eigensystem. This approach was designed to avoid problems associated with previous colour mapping schemes, in particular to avoid discontinuities in the colour mapping and reduction of computational time. The method is applied to a normalized brain dataset comprising 30 healthy individuals. Visualisations of brain stem structures, thalamic structures and the recently described three segment model of the arcuate fasciculus are demonstrated. Additionally, this technique provides several geometric parameters that may be useful for streamline segmentation algorithms.

Poster Sessions

310

1834. Whole Brain White Matter Tract Segmentation of Single Subject Diffusion Tensor Tractography Data Thomas Richard Barrick1, Nigel Lawes1, Chris A. Clark2 1Saint George's, University of London, London, UK; 2University College London, London, UK

Here we present an algorithm for clustering of tracts throughout the white matter of the entire brain which requires the user to simply identify the constituent parts of the tract of interest. We show that this is robust when applied to DTI datasets of individual subjects. This allows rapid tract extraction to be performed without the need for group mapping or averaging of datasets, therefore maintaining characteristic features of individual subjects.

1835. Diffusion Tensor MRI Can Anatomically Segment Human Amygdaloid Subnuclei in Vivo Eugenia Solano-Castiella1, Alfred Anwander1, Carol Docherty1, Enrico Reimer1, Marcel Weiss1, Angela D. Friederici1, Robert Turner1 1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany

The amygdaloid subnuclei are hard to distinguish using standard MRI. Their differential connectivity to other brain areas suggests that each might have a preferential internal fiber orientation. In this study we provide evidence for the segmentation of amygdaloid nuclei, using DTI data obtained in-vivo in 15 subjects and clustered with an automatic K-means algorithm. This finding may assist in discrimination of the distinct roles of these nuclei in processing of emotions and cognitive function, and in psychiatric disorders.

1836. Group Analysis of Human Brain White Matter Using Mean Path Analysis Method Wen-Yang Chiang1, Van J. Wedeen2, Wen-Yih Isaac Tseng1 1National Taiwan University College of Medicine, Taipei, Taiwan; 2MGH Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, USA

While globally optimized normalization was achieved, the performance of alignment for local structure, empirically, was not always guaranteed. In this study, we proposed a simple and effective strategy for group analysis of human white matter via co-registration of inter-subject mean paths of the tract bundles. Using the affine transform matrix estimated from coregistration of B0 images, the length of mean pathways of individual white matter could be normalized inhomogeneously. In addition to obtaining the averaged structural information, we can also analyze the change of the averaged tract bundle in a more reasonable way.

1837. A Ground Truth Analysis of the Preservation of Diffusion Tensor Information in a Population Specific Atlas Wim Van Hecke1, 2, Alexander Leemans3, Steve De Backer1, Everhard Vandervliet2, Jan Sijbers1, Paul M. Parizel2 1VisionLab, University of Antwerp, Antwerp, Belgium; 2University Hospital Antwerp, University of Antwerp, Antwerp, Belgium; 3CUBRIC, University of Cardiff, Cardiff, UK

An important requisite for voxel based morphometry, studies is the use of a non-rigid coregistration technique, and the availability of a population specific atlas. In this context, aDTI atlas is created that preserves theorientational DT information and contains a minimal bias towards any individual image. To evaluate the proposed atlas, a ground truth method is developed using a single subject DT image that is deformed with 20 deformation fields. We demonstrate that the atlas contains all orientational diffusion information accurately and precisely, due to the use of all DT elements during coregistration and the specific atlas construction methodology.

1838. Probabilistic Tract-Based Atlas with High Angular Resolution Diffusion Imaging Yi-Ping Chao1, Chun-Hung Yeh2, Kun-Hsien Chou2, Kuan-Hung Cho1, Jyh-Horng Chen1, Ching-Po Lin2 1National Taiwan University, Taipei, Taiwan; 2National Yang-Ming University, Taipei, Taiwan

In this study, we proposed a tract-based transformation to realign the multi-fiber trajectories with high angular resolution diffusion imaging. Transformation matrices were estimated by coregistering T1-weighted image of each subject to MNI-152 brain image using a 12-parameters affine linear registration. The matrices were then applied to the propagated neural bundles from individual subjects derived from QBI with MFACT tracking algorithm. By summarizing individual transferred tracts in the standard MNI-152 coordinate, a probabilistic tract-based atlas can be generated to assist clinical studies into the variations of complex connectivity between different subjects.

1839. A Comparison of Seeding Strategies for Group Tractography Jonathan Daniel Clayden1, Amos J. Storkey2, Mark E. Bastin2 1University College London, London, UK; 2University of Edinburgh, Edinburgh, UK

The aim of this work was to illustrate and discuss the effects of applying common seeding strategies for tractography to a typical data set. Single and multiple seed approaches are compared with regard to their usefulness for robust segmentation in groups. We also examine the effects of thresholding on the results. We find that single seed strategies can be successful, whilst ROI methods using a group of seed points may not be as reliable as is often assumed.

1840. Probabilistic Combination of Tractography Data from Multiple Seed Points for White Matter Segmentation Jonathan Daniel Clayden1, Amos J. Storkey2, Mark E. Bastin2 1University College London, London, UK; 2University of Edinburgh, Edinburgh, UK

This work describes how a probability distribution based on topological tract matching can be used to combine information derived from tractography for multiple seed points. This process provides broader coverage of a white matter structure of interest than data from a single seed voxel would, whilst maintaining high confidence in the segmentation. We also demonstrate that this approach mitigates the tendency for voxels with very high probability of connection to the seed point to be overrepresented in tractographic output.

Poster Sessions

311

1841. Application of a Double Inversion-Recovery Sequence to Diffusion Tractography Simon J. P. Meara1, David M. Morris1, Karl V. Embleton1, Hamied A. Haroon1, Geoffrey J. M. Parker1 1University of Manchester, Manchester, UK

Areas of activation detected by functional magnetic resonance imaging (fMRI) experiments have previously been used to define seed regions for diffusion tractography. The present study has used a white matter-selective double inversion-recovery image to restrict regions of interest (ROIs) derived from fMRI results to contain only grey matter. It was found that the tractography results showed loci where a higher probability of connection was detected when using the whole ROIs, as compared to using the restricted ROIs. It must therefore be ensured for future studies that the ROIs used do not contain any of the surrounding white matter.

1842. Reproducible Quantification of Fiber Integrity Profiles in the Cingulum and the Fornix Using an Experimental 32 Channel Head Coil Bram Stieltjes1, 2, Jan Klein3, Ben Hyman2, L G. Naul2, Val Runge2, Marco Essig1 1DKFZ, Heidelberg, Germany; 2Scott and White Hospital, Temple, USA; 3MeVis Research, Bremen, Germany

The combination of parallel imaging (PI) and high field strength holds great promise for the improvement of EPI-based DTI and fiber tracking as shown previously. Here we show the first result using an experimental 32 channel head coil for depiction and quantification of small, strongly curved fibers such as the fornix and the cingulum. We show that within 4 minutes data can be obtained that allow for a reproducible quantification of fiber integrity in these structures. This method can be used for investigation of these structures in psychiatric diseases like Alzheimer’s and autism.

1843. Acquiring Optimal DWI Data for Tractography on Post Mortem Brain Tissue Tim Bjørn Dyrby1, Jacob Jelsing2, Daniel C. Alexander3, Lise V. Søgaard1 1Copenhagen University Hospital Hvidovre, Hvidovre, Denmark; 2Copenhagen University Hospital Bispebjerg, Bispebjerg, Denmark; 3University College London, London, UK

The use of fixated post-mortem brains allows validation of mathematical models in a neuronal environment close to in vivo. However, lowered temperature and the process of fixation decrease the diffusion coefficient observed post-mortem. A wide range of b-values were investigated on a perfusion fixated pig brain. DWI data was acquired in one continuous scanning session and reconstructed using two methods with the ability to detect single and complex fibre compositions. For detection of crossing fibers a lower bound of b>2475s/mm2 was found. An upper bound was found to be b<8181s/mm2, and likely dependent upon the noise floor.

1844. Visualization of the Cingulum Bundles In-Vivo Using Optimized MR Diffusion Spectrum Imaging marzieh Nezamzadeh1, Van Wedeen, Ruopeng Wang, Yu Zhang1, Wang Zhan1, Karl Young1, Michael Weiner1, Norbert Schuff1 1Radiology, University of California San Francisco, san francisco, California , USA

Previous DTI studies have shown that diffusion measurements at the tract level of cingulum fibers might yield a powerful marker of incipient AD pathology. However, DTI results can be ambiguous, especially in areas of crossing nerve fibers. Diffusion spectrum imaging (DSI) is more powerful than DTI and likely more sensitive to alterations of the cingulum bundles in AD. Our aim in this in-vivo 4T study on humans was therefore to optimize DSI parameters, especially spatial resolution and diffusion encoding to be able to accurately resolve the cingulum bundles for tract level measurements of diffusion. This study significantly demonstrates a reproducible identification of the cingulum bundles of human brain based on DSI acquisition with only 12 minutes duration. The gold standard setting provided from this study will be used for detection of the cingulum fibers in aging, mild cognitive impairment and Alzheimer’s disease.

1845. Reconstruction of Brainstem White-Matter Fiber Systems with Combinatorial Tracking Shlomi Lifshits1, Arie Tamir, Yaniv Assaf 1Tel-Aviv University, Tel-Aviv, Israel

Tractography enables delineation of white matter trajectories. Recently we suggested the combinatorial tracking framework in which the DTI data is mapped to a graph, were the center of each voxel is connected to its neighbor voxel centers by graph edges. Here, we applied combinatorial tracking to reconstruct two fiber systems in the Brainstem: the pyramidal decussation (PD) and the medial cerebellar peduncle (MCP). We compare the results of the two reconstruction algorithms: the most probable random walk path and reaction path algorithms. Although both successfully reconstruct the PD, only the later reconstructs the MCP in an anatomically consistent manner.

1846. Fuzzy Anatomical Connectedness Using Diffusion MRI: An Approach to Tractography of the Brain Stamatios N. Sotiropoulos1, Christopher R. Tench1, Li Bai1 1University of Nottingham, Nottingham, UK

We present a new framework for tract reconstruction from diffusion-weighted MR images. Given that medical images are inherently fuzzy due to physical limitations of the imaging device, we utilise a fuzzy connectedness algorithm. The strength of connectivity between any two voxels is assessed by examining all possible pathways connecting them to find the strongest path. We show how this algorithm can be applied to tract extraction using local fibre orientation estimates. Maps of the calculated connectedness values can be used to infer connectivity between a seed voxel and all other voxels in the brain.

1847. Investigating the Anatomical Substrate of Functional Networks Obtained at Rest: A Combined FMRI and Fiber Tracking Approach Arnaud Messé1, Vincent Perlbarg1, Guillaume Marrelec1, Mélanie Pélégrini-Issac1, Habib Benali1, 2 1Inserm and Université Pierre et Marie Curie, Faculté de médecine Pitié-Salpêtrière, Paris, France, Metropolitan; 2Université de montréal, Montréal, Canada

This work investigates anatomo-functional connectivity in the human brain. Functional networks were identified from resting-state fMRI data using Independent Component Analysis. Using DTI data from the same subjects, a probabilistic fiber tracking method revealed the anatomical structure of the networks. Functional and anatomical connectivity indices were defined (functional correlation and mean number of fibers between pairs of regions in all networks, respectively) and a Multidimensional Scaling analysis was used to study the functional and anatomical organization of the networks. Results show similarities between functional and anatomical connectivities, supporting the existence of an underlying anatomical substrate for the functional networks.

Poster Sessions

312

1848. Fast-Marching Tractography for Connection Matrix (Fast-TraC) Xavier Gigandet1, Leila Cammoun1, Reto Meuli2, Jean-Philippe Thiran1, Patric Hagmann1, 2 1Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; 2Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland

Although high angular resolution diffusion MRI techniques are able to solve multiple intra-voxel fiber orientations, the usual streamline Diffusion Spectrum Imaging (DSI) tractography algorithms present some limitations in their ability to map complex fiber-crossings in the brain white matter because they select locally only the most linear trajectories. In this work, we present a fast marching tractography algorithm for DSI, called Fast-TraC, which 1) is able to efficiently address this issue, 2) creates fiber trajectories between 1000 small cortical ROIs covering the entire brain and 3) builds a whole brain connection matrix. We also see selected tracts that are accurately reconstructed.

1849. The Application of Point Spread Function Weighting in Probabilistic Tractography David Mark Morris1, Sha Zhao1, Geoff JM Parker1 1University of Manchester, Manchester, UK

In probabilistic tractography linear interpolation is generally used to determine the weighting of the probability of selecting the streamline prorogation direction from neighbouring Probability Density Functions. Using the point spread function of the imaging acquisition has the potential to more realistically determine the weightings and improve the probabilistic tracking results. These point spread function weighting were determined the probability of selecting a particular Probability Density Function is compared between this implementation and the linear weighting at different positions. Differences observed are variable potentially influencing tractography results depending on the tracking environment.

1850. DTI Fiber Volume Measurement Using a Wrapping Algorithm Bin Chen1, 2, Allen W. Song1 1Duke University, Durham, North Carolina, USA

DTI fiber tractography can potentially lead to quantitative assessment of brain development and pathology, provided that the size and volume of the neuronal fibers can be accurately measured. However, the relatively low resolution of DTI makes the voxel counting technique, the most commonly used method to estimate the fiber volume from tracked trajectories, less accurate because it has inherent partial volume effect. A fiber wrapping algorithm is proposed here to reduce such an effect for more accurate volume measurement.

1851. Development of DT-MRI Muscle Fiber Tracking Algorithms Bruce M. Damon1, Zhaohua Ding1 1Vanderbilt University, Nashville, Tennessee, USA

Diffusion-tensor MRI is a promising tool for structural characterization of muscle, including fiber tracking. Partial volume artifacts due to intramuscular fat deposition require the development of new tracking algorithms capable of proper muscle fiber trajectories on the basis of readily measurable MR parameters. Here we use Monte Carlo simulations to test two sets of stop criteria and four interpolation schemes. We found that stop criteria using linear weighting of T2-weighted signal, FA, and curvature combined with nearest-neighbors interpolation provided optimum tracking results.

1852. Comparison of DT Tractography Algorithms with MEMRI and BOOT-TRAC Chia-Ling Chen1, Kuan-Hung Cho2, Ke-Hsin Chen1, Ching-Po Lin1 1National Yang-Ming University, Taipei, Taiwan; 2National Taiwan University, Taipei, Taiwan

Three tractography algorithms, FACT, RungeKutta method (RK), and TEND, are evaluated by bootstrap tractography (BOOT-TRAC) and manganese-enhanced MRI (MEMRI). By changing the number of averages from 1 to 7, the success rate and the tolerance to noise are assessed. The results show that the higher success rate is obtained for all algorithms while higher SNR is achieved. For RK, the step size may also affect the results of tractography. In addition, the success rate of RK is generally higher than that of FACT and TEND. RK also gives a higher reliability for estimating neuronal connections.

1853. Establishment of the In Vivo Tracing of Spinal Pathway Using Diffusion Tensor Tractography in Nonhuman Primates Kanehiro Fujiyoshi1, Masaya Nakamura, Masayuki Yamada, Keigo Hikishima, Junichi Yamane, Hiroyuki Katoh, Kazuya Kitamura, Osahiko Tsuji, Seiji Okada, Akio Iwanami, Suketaka Momoshima, Yoshiaki Toyama, Hideyuki Okano 1Keio University school of medicine, Shinjuku, Japan

The evaluation of axonal fibers is essential to assess the spinal cord injury (SCI), but conventional methods are highly invasive, precluding clinical applications. We therefore sought to establish a non-invasive method to evaluate axonal fibers in vivo using diffusion tensor tractography (DTT). In this study, we performed DTT of both intact and injured spinal cords in common marmosets and confirmed the accuracy of DTT through histology. Our results revealed that DTT can depict the course and the disruption of specific neural pathways even in live animals, demonstrating the possible contribution of DTT to the clinical studies of SCI therapy.

1854. Simulations of DTI Voxel Size Resolution on Fiber Tract Measurements Daniel T. Franc1, Kelvin O. Lim 1University of Minnesota, Minneapolis, USA

Diffusion tensor imaging (DTI) is being increasingly used to determine the orientation, size, and degree of anisotropy of individual white matter tracts for research studies and clinical practice protocols. The relatively low resolution for DTI leads to voxels that will partially sample anatomically separate tracts throughout the white matter when tracts have a similar size or smaller. This study uses modeled fiber tracts downsampled at different voxel resolutions to measure the uncertainty inherent in tract-specific DTI region-of-interest and fiber tracking measurements.

Poster Sessions

313

1855. A Comparative Study of Diffusion Tensor Field Transformations Madhura Aditya Ingalhalikar1, Jinsuh Kim1, Vincent A. Magnotta1, Andrew Alexander2 1University of Iowa, Iowa City, Iowa, USA; 2University of Wisconsin, Madison, Wisconsin, USA

Diffusion tensor (DT) magnetic resonance imaging is unique in its ability to non-invasively visualize the white matter fiber tracts in human brain in vivo. MR diffusion is based on microscopic diffusion of water molecules which is a truly three dimensional process. A symmetric second rank tensor is often used as a model for characterizing the diffusion. Diffusion tensors contains orientational information that is affected by the transforms applied during image registration. Therefore, this directional information needs to be correctly rotated such that the tensors are consistent with the tissue reorientation caused by application of the resulting transformations. Previous work carried out in this area concentrates on reorientation of tensors by different methods. Xu et al (2003) have used the transformation and fiber direction estimate to reorient the tensors. Alexander et al (2001) have implemented the preservation of principle direction method. We have addressed this problem with a novel technique where the rotation in applied to the diffusion sensitizing gradients providing a voxel by voxel estimate of the diffusion gradients instead of a volume of by volume estimate. We have compared our technique with an existing method where the transformation is applied to the resulting diffusion tensors. In both the methods, rotation is computed from the deformation field by decomposing the local linear transformation.

Crossing Fibers & Non-Tensor Approaches Hall D Wednesday 13:30-15:30

1856. A Tensor Based Approach to Crossing Fibers Using the Wild Bootstrap Ai Wern Chung1, Thomas Richard Barrick2, Chris A. Clark1 1UCL, Institute of Child Health, London, UK; 2Saint George's, University of London, London, UK

Multiple-fiber reconstruction algorithms are often mathematically and computationally intensive. We present a simple method for detecting crossing structures by using k-means clustering to group principal eigenvector distributions provided by the Wild bootstrap diffusion tensor model into two populations. Using this Wild-tensor approach, we were able to produce results in the frontal pericallosal region comparable to the Q-Ball method on a 60-directional dataset at b = 0 - 3000s mm-2. Our method shows potential by providing plausible trajectories. Furthermore, the availability of bootstrapped data enables calculation of a variety of indices within and between cluster groups.

1857. Random Effects Modelling of Crossing Fibre Voxels in Diffusion MRI Martin D. King1, David G. Gadian1, Christopher A. Clark1 1UCL Institute of Child Health, London, UK

Synopsis Random effect (RE) models were applied to the crossing-fibre problem that arises in the analysis of multiple-directions diffusion-weighted MR data. Among these models is the Besag-York-Mollie model, which includes both exchangeable and spatial RE terms. The analyses were performed using a Markov chain Monte Carlo algorithm (Gibbs sampling). Two crossing fibre brain regions were used to show that RE modelling provides a useful alternative to current methods documented in the MR tractography literature.

1858. Multi-Model Diffusion Image Analysis: A Correlative Study Between Diffusion Spectrum Imaging and Diffusion Tensor Imaging on Structural Lateralization Wen-Yang Chiang1, Li-Wei Kuo2, Van Jay Wedeen3, Wen-Yih Isaac Tseng1 1National Taiwan University College of Medicine, Taipei, Taiwan; 2Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan; 3MGH Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, USA

Since there are dramatic differences between each diffusion-based imaging modality, it is challenging to compare different diffusion indices from different imaging modalities. In this study, we used DSI data to analyze structural lateralization of arcuate fasciculus and compared the result which used DTI reconstruction method. The experiment results showed that both diffusion indices and lateralization index are highly correlated between DTI and DSI which means that the structural analysis, even with different diffusion imaging modalities, is comparable. This fundamental study, which might be the first one that compares diffusion indices and lateralization between different diffusion imaging modalities, may facilitate inter-sites collaborations of diffusion MR researches.

1859. Improved Detection of Non-Gaussian Diffusion with Nonlinear Fitting at High B-Values Ryan Fobel1, Greg Stanisz2 1University of Toronto, Toronto, Canada; 2Sunnybrook HSC, Toronto, Canada

Higher-order diffusion models, including those based on the Spherical Harmonics and Generalized Diffusion Tensors, are typically fit using linear least-squares methods. This leads to limited performance at high b-values. A nonlinear fitting algorithm which compensates for magnitude bias results in more accurate fitting at b-values of up to 3000 s/mm2. The performance of model selection (ie. classification of voxels as having either isotropic, non-isotropic Gaussian or non-Gaussian diffusion) is significantly improved with this new fitting method. Experimental results show that more than twice as many voxels exhibiting non-Gaussian diffusion are detected at b=2000 s/mm2 relative to b=1000 s/mm2.

1860. A Modified Damped Richardson-Lucy Algorithm to Improve the Estimation of Fiber Orientations in Spherical Deconvolution Flavio Dell'Acqua1, 2, Paola Scifo1, Giovanna Rizzo, 12, Giuseppe Scotti1, Ferruccio Fazio1, 2 1San Raffaele Scientific Institute, Milan, Italy; 2IBFM-CNR University of Milano-Bicocca, Milan, Italy

The presence of partial volume effect between white matter and isotropic tissues can increase the number of instabilities and spurious fiber orientations in spherical deconvolution methods. In this work, we proposed a modified damped version of the Richardson-Lucy algorithm to improve results also in these regions. Simulation and in-vivo results are shown.

Poster Sessions

314

1861. A Regularised Two-Tensor Model Fit to Low Angular Resolution Diffusion Images Stamatios N. Sotiropoulos1, Christopher R. Tench1, Li Bai1, Paul S. Morgan1, Dorothee P. Auer1, Cris S. Constantinescu1 1University of Nottingham, Nottingham, UK

Diffusion Tensor Imaging (DTI) is prone to partial volume artefacts. Given that routine clinical use of high angular resolution diffusion imaging is still tentative, a regularised two-tensor model to resolve fibre crossings from conventional DTI datasets is presented. The model utilizes the planar diffusion profile depicted by DTI in regions of crossing fibres. Relaxation labelling is then applied to regularise and preserve slow changes in the two resolved orientations across a neighbourhood. Orientational, anisotropy, and diffusivity information can be resolved in regions of two fibre crossings using full brain coverage scans acquired in less than 6 minutes.

1862. A Comparison Between Diffusion Tensor Imaging and Q-Ball MRI in the Study of Post-Stroke Plasticity Cristina Granziera1, Thomas Benner2, Ashok Kumar2, Dave Tuch2, Aneesh Singhal3, Walter Koroshetz3, Gregory Alma Sorensen2 1CHUV, Lausanne, Switzerland; 2Martinos Center-MGH-Harvard medical school, Charlestown, Massachusetts, USA; 3MGH, Boston, Massachusetts, USA

Diffusion tensor imaging (DTI) has been advocated as a valuable non-invasive tool to monitor post-stroke recovery. However, its inaccuracy in regions of fibers crossing/kissing could limit its application in studying the complex white matter plasticity characterizing functional recovery after stroke. We compared DTI to q-ball imaging in the study of white matter remodeling during stroke recovery of five patients with small ischemic MCA strokes. Qball MRI appeared to be more accurate than DTI in monitoring post-stroke plasticity because : 1. it showed more fiber trajectories at all time points ; it better unraveled longitudinal qualitative and quantitative modulations of fiber tracts ; it disentangled some fibers which appeared to "cross" the compact structure of the cortico-spinal tract.

1863. Real-Time MR Diffusion Tensor and Q-Ball Imaging Using Kalman Filtering Fabrice Poupon1, 2, Alexis Roche1, 2, Jean-François Mangin1, 2, Cyril Poupon1, 2 1CEA,NeuroSpin, Saclay, France; 2IFR49, Saclay, France

Magnetic resonance diffusion imaging has become an established technique for inferring structural anisotropy of tissues and mapping the white matter connectivity of human brain. We developed a method to process diffusion tensor and Q-ball imaging in real-time. The basic idea is to use a Kalman filtering framework to fit either the linear tensor or Q-ball model incrementally, thus updating the model estimate after the acquisition of any new diffusion-weighted volume during ongoing scans.

1864. Comparison Between Q-Ball Reconstructions Using Radial Basis Function and Spherical Harmonic Basis Chun-Hung Yeh1, Kuan-Hung Cho2, Ching-Po Lin1, 3 1Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan; 2Interdisciplinary MRI/MRS Lab, Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan; 3Institute of Neuroscience, National Yang-Ming University, Taipei, Taiwan

A systematical comparison between q-ball imaging (QBI) reconstruction using radial basis function (RBF) and spherical harmonic basis (SHB) is performed in this study. For both reconstruction methods, the accuracy in defining fiber orientations is assessed using a diffusion phantom model of 45¢X fiber crossing. The results show that both RBF QBI and SHB QBI are capable of resolving crossing fibers, while the separation angles may be underestimated using an insufficient b-value. We propose that b-value is the predominant factor to determine the intrinsic angular resolution in QBI.

1865. Multi-Shelled Q-Ball Imaging: Moment-Based Orientation Distribution Function Eizou Umezawa1, Mayo Yoshikawa2, Kana Ohno3, Emi Yoshikawa4, Kojiro Yamaguchi1 1Fujita Health University, Toyoake, Japan; 2NGK Insulators, Ltd., Nagoya, Japan; 3Gifu Public Health Center, Kakamigahara, Japan; 4Kyushu Koseinenkin Hospital, Kitakyusyu, Japan

We propose a method that calculates an orientation distribution function (ODF) based on the moments of the probability density function of diffusion displacement. The method is based on q-ball imaging and an idea of "q-space imaging using small magnetic field gradient" that have been proposed in our previous work. The ability of the ODF to identify fiber crossing is also investigated by numerical simulation. The results imply the possibility that the moment-based ODF can reduce the number of data acquisition measurements in keeping higher ability to identify fiber crossing.

1866. Splines on the Sphere Q-Ball Imaging Nader Metwalli1, 2, John D. Carew, 3, Xiaoping P. Hu1 1Georgia Institute of Technology / Emory University, Atlanta, Georgia, USA; 2Cairo University, Cairo, Egypt; 3Georgia Institute of Technology, Atlanta, Georgia, USA

We present splines on the sphere as a method of modeling raw high angular resolution diffusion imaging (HARDI) data with the added feature of smoothing of the diffusion data in the 3D diffusion space. With an extension to Q-Ball imaging (QBI), Splines on the Sphere QBI (S2QBI) resultant orientation distribution functions (ODFs) are of better quality than their QBI counterparts without compromising angular directionality which will be beneficial in QBI-based fiber tracking applications.

Diffusion & Perfusion Studies in Animal Models Hall D Thursday 13:30-15:30

1867. Rapid High-Field Diffusion MR Histology: Image-Based Phase Correction for Diffusion-Weighted RARE Julian Michael Tyszka1, Lawrence R. Frank 1California Institute of Technology, Pasadena, California , USA

Two phase correction schemes for eddy-current ghosting in high-field diffusion-weighted RARE imaging are presented. The schemes are tailored for efficient MR diffusion histological studies of samples such as fixed rodent brains, in which physiological motion is absent and per-acquisition navigation can be eliminated. The effectiveness of both approaches is demonstrated in rat brain samples.

Poster Sessions

315

1868. Altered Fiber Connectivity in Adult Brain of PAX6 Knock-Out Mice Revealed by DTI in Vivo Susann Boretius1, Anastassia Stoykova1, Roland Tammer1, 2, Jens Frahm1, Thomas Michaelis1 1Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany; 2DFG Center of Molecular Physiology of the Brain (CMPB), Göttingen, Germany

Cortex specific conditional knock-out of transcription factor PAX6 at the beginning of neurogenesis in mice results in almost full abolishment of the upper cortical layers. To assess putative structural abnormalities in the cortex at maturity, pairs of mutant and control mice were studied by diffusion tensor imaging (DTI). Tracking of major neuronal fiber bundles revealed a lack of interhemispheric connectivity as well as pronounced fiber reorganization in the septal region and fimbria. These findings indicate an important role of PAX6 in establishment of the intracortical fiber connectivity.

1869. Quantifying Cerebral Blood Volume Over the Mouse Cerebral Cortex Using Micro-CT Co-Registered to an MRI Anatomical Atlas Brige P. Chugh1, Jason P. Lerch1, Lisa X. Yu1, R Mark Henkelman1, John G. Sled1 1Mouse Imaging Centre,Toronto Centre for Phenogenomics, Hospital for Sick Children, Toronto, Canada

Measurement of the cerebral blood volume (CBV) in local regions of the mouse brain will be useful to describe the phenotypes of models of neurodegenerative diseases that alter microvasculature including Alzheimer’s disease. A limitation of current methods to determine CBV in mice, including MRI methods sensitive to magnetic susceptibility changes, is that they do not provide absolute quantification of CBV over the entire mouse cerebral cortex. To overcome this difficulty, we developed a method to determine absolute CBV over the mouse cortex using micro-computed tomography (micro-CT) co-registered to an MRI anatomical brain atlas.

1870. Diffusion Tensor Imaging Detects and Characterizes Proliferative Diabetic Retinopathy in the Murine Retina Saurav Chandra1, Angelos Barmpoutis1, John Forder1 1University of Florida, Gainesville, USA

The specific aim in this study is to prove that the alterations in the eye following damage (by laser damage and diabetic retinopathy) can be detected by DTI. This is done by comparing the fractional anisotropies in the retinas of controls versus diabetic eyes. The mice had been subjected to Type I diabetes. The experiments were successful in determining significant differences between the fractional anisotropies of retinas in controls compared to the lasered as well as diabetic retinas. Future studies will involve in vivo imaging of mice with various stages of the disease.

1871. In Vivo Quantification of Lamina T1, T2, and Apparent Diffusion Coefficient in the Mouse Retina at 11.74T Junjie Chen1, Qing Wang1, Huiying Zhang1, Xiaoxia Yang1, Jian Wang2, Bruce A. Berkowitz3, Samuel A. Wickline1, Sheng-Kwei Song1 1Washington University, St. Louis, Missouri, USA; 2Chinese Pharmaceutical Association, Beijing, People's Republic of China; 3Wayne State University, Detroit, Michigan, USA

Quantitative MRI of the mouse retina (~ 250 µm thick) is challenging due to its limited thickness. In the present study, T1 and T2 relaxation time constants, and the directional apparent diffusion coefficient (ADC) in three MR-detected retina layers of C57/BL6 mice were measured at 47 x 47 x 400 µm 3 resolution. This study establishes, for the first time, normative metrics of T1, T2, and ADC of the mouse retina. These MR parameters are expected to be useful in future evaluation of developmental and pathological alterations of retinal cell layers in mice.

1872. Blood-Flow MRI of Retinal Degeneration Yingxia Li1, Haiying Cheng1, Qiang Shen1, Moon K. Kim2, Darin E. Olson1, Peter M. Thule1, Machelle T. Pardue2, Timothy Quyen Duong1 1Emory University, Atlanta, Georgia, USA; 2Department of Veterans Affairs Medical Center, Atlanta, Georgia, USA

Vision loss due to retinal degeneration is a major problem in clinical ophthalmology. We have previously reported a thinning of the retina and perturbed BOLD fMRI responses to physiologic challenges in the retina of an animal model of progressive retinal degeneration (Royal-College-of-Surgeons rats). In this study, we extend previous findings by studying basal blood flow (BF) and physiologically induced BF changes in RCS rat retinas and age-matched controls at 90x90x1500-ƒÝm. Quantitative BF was measured using the continuous arterial-spin-labeling technique. MRI provides quantitative BF data without depth limitation and large field-of-view and could complement existing retinal imaging techniques.

1873. Quantification of Perfusion and Blood Volume in the Brains of Rats Breathing Carbogen Using ASL and a Two Compartment Model John Carr1, David Buckley1, Jean Tessier2, Geoff Parker1 1University of Manchester, Manchester, UK; 2AstraZeneca, Macclesfield, UK

ASL is shown to be a feasible method for measuring F in a subcutaneous tumour model and sensitive enough to quantify changes resulting from carbogen breathing. A positive correlation is shown between T2* change and F change due to carbogen (r = 0.68, p = 0.01) and between ADC and F (r = 0.67, p =0.04). No correlation was found between IAUC and F indicating IAUC measurements are dominated by CA leakage. In summary, a novel application of the ASL technique is demonstrated showing how ASL can be used in tumours outside the brain in animals and potentially in humans.

1874. Arterial Spin Labeling Quantification of Cerebral Blood Flow and Cerebrovascular Reactivity to Carbon Dioxide in Normotensive and Hypertensive Rats: A Comparative Study Fernando F. Paiva1, 2, Erica C. Henning1, Alberto Tannus2, Afonso C. Silva1 1National Institutes of Health, Bethesda, Maryland, USA; 2Universidade de Sao Paulo, Sao Carlos, Brazil

Cerebral blood flow under basal and hypercapnic condition (5% and 10% CO2) were obtained in normotensive and hypertensive rats using a continuous ASL EPI sequence with a a three coil system comprised of a homogeneous volume excitation coil, a receive-only quadrature surface coil and a dedicated labeling RF coil. Higher CBF values were found in hypertensive rats both under normocapnia and hypercapnia. While the vascular reactivity under 5% carbon dioxide was not significantly different amongst both strains, the hypertensive rats displayed impaired reactivity when submitted to 10% CO2.

Poster Sessions

316

1875. Dynamic Arterial Spin Labeling Functional MRI (DASL-FMRI) Fernando F. Paiva1, Bojana Stefanovic1, Yoshiyuki Hirano1, Alberto Tannus2, Afonso C. Silva1 1National Institutes of Health, Bethesda, Maryland, USA; 2Universidade de Sao Paulo, Sao Carlos, Brazil

Dynamic arterial spin labeling (DASL) is an efficient way to quantitatively measure cerebral blood flow (CBF), the transit-time τƒnof the endogenous labeled arterial water and T1 of the brain. In this work, we combine DASL with fMRI experiments during somatosensory stimulation in rats. We show that the combination of DASL with fMRI constitutes an interesting approach to obtain, in a single experiment, dynamic quantification of both resting and functional hemodynamics with improved efficiency and SNR. This new methodology is poised to become a versatile experimental plat-form for studying the spatial and temporal characteristics of functional cerebral hemodynamics.

1876. Agonists of Alpha2-Adrenoceptors and Imidazoline Receptors Show Selectivity-Related Differential Effects on Cerebral Blood Flow in Rat: An MR Perfusion Imaging Study Xiao-xia Du1, Fu-chun Lin2, Hao Lei1 1Wuhan Institute of Physics and Mathematics, Chinese Academy of Science, Wuhan, People's Republic of China; 2 Wuhan Institute of Physics and Mathematics, Chinese Academy of Science, Wuhan, People's Republic of China

Agonists/antagnoists of alpha2-adrenoceptor and imidazoline receptor are known to have the ability to affect cerebral blood flow (CBF). Xylazine, clonidine and moxonidine have different receptor affinities for alpha2-adrenoceptors and imidazoline receptors. In this study, continuous arterial labeling (CASL) perfusion imaging was used to investigate the effects of xylazine, clonidne and moxonidine on CBF in rats. The results showed that, at the dosages used, the three drugs induced similar cardiovascular responses, but significantly different effects on CBF.

1877. Insulin Reverses Attenuation of Cerebral Blood Flow (CBF) Caused by Hyperglycemia in a Mouse Model of Diabetes: Potential Impact on Acute Ischemic Stroke Samir Kamalesh Amin1, Faridis Serrano1, Tomoya Terashima1, Lawrence Chan1, Lingyun Hu1, Robia G. Pautler1 1Baylor College of Medicine, Houston, Texas, USA

Diabetes is associated with microvascular disease and believed to increase cerebrovascular complications, particularly acute ischemic strokes. Studies have shown that both acute and chronic hyperglycemia cause cerebral blood flow (CBF) reduction, however, little is known about the mechanism of change. We used an in vivo mouse model of diabetes not only to evidence reduced CBF utilizing Flow-sensitive Alternating Inversion Recovery (FAIR) arterial spin labeling (ASL), but also to determine if this vascular effect is reversible by modifying glucose levels with insulin. In conclusion, we observed CBF reduction in a diabetic mouse model (STZ) and witnessed an “insulin rescue” in CBF.

1878. High-Field MRI Detection of Magnevist Permeation Into Normal Mouse Brain Parenchymal and Ventricular Spaces Martin M. Pike1, 2, William D. Rooney2, Xin Li2, Christine Neumann Stoops1, G Yancey Gillespie1, Charles S. Springer2 1University of Alabama at Birmingham, Birmingham, USA; 2Oregon Health & Science University, Portland, USA

Recent evidence suggests that contrast agent (CA) permeation into normal brain parenchyma is detectable with high-field MRI, which should increase detection sensitivity via tissue 1H2O T1 increases, concomitant with greater CA-induced T1 reductions. During gradual, sustained GdDTPA2- infusions, we observed substantial image intensity increases in the normal mouse brain ventricular system, and in non-ventricular parenchyma, using ultra high-field MRI (8.5T). These data provide clear and convincing evidence of standard monomeric Gd(III) chelate MRI CA permeation into normal brain parenchyma, consistent with improved CA detection sensitivity at high-field, potentially enabling implementation of powerful new CA approaches in normal and diseased brain.

1879. Cerebral Blood Volume Alterations After Traumatic Brain Injury in the Rat Brain - 2 Weeks MRI Follow-Up Riikka Johanna Immonen1, Juha Yrjänheikki2, Taneli Heikkinen2, Leena Tähtivaara2, J Puoliväli2, R I. Grundy3, T Tuinstra4, A Phinney4, B Van Vliet4, Olli Gröhn1 1A.I.Virtanen Institute for Molecular Sciences, University of Kuopio, Kuopio, Finland; 2Cerebricon Ltd., Kuopio, Finland; 3Cerebricon Ltd., London, UK; 4Solvay Pharmaceuticals BV, CP Weesp, Netherlands

Hypoperfusion may have a role in the secondary injury cascade following traumatic brain injury. We measured relative cerebral blood volume (CBV) changes and diffusion in rat brain following cortical impact injury aiming to find out more about the hemodynamics in the perifocal area surrounding the lesion. The Δ R2 and Δ;R2* maps using iron oxide contrast agent and average diffusion maps were acquired at 1h, 2h, 4h, 1d, 2d, 3d, 4d, 7d and 14d after TBI. Both Δ R2 and Δ;R2* showed acute drop in CBV in the perifocal area, which then started to recover. Yet even after 14d, ΔR2 remained decreased.

1880. Velocity Selective Arterial Spin Labeling in Rat Brain Kim C.C. van de Ven1, Rick M. Dijkhuizen1, Ivo A.C.W. Tiebosch1, Annette Van der Toorn1 1University Medical Center Utrecht, Utrecht, Netherlands

Velocity Selective Arterial Spin Labeling (VSASL) is an ASL-based perfusion MRI technique that magnetically labels blood spins based ontheir velocity instead of their spatial position. Thus far VSASL perfusionimaging has not yet been assessed for application in an animal model. We measured VSASL subtraction signal in in vivo rat brain at 9.4T, which diminished to noise level after asphyxiation. Our study demonstrates that VSASL can be successfully applied in rat brain studies.

1881. Automatic Analysis of Quantitative Cerebral Perfusion in Rodents Rui Liu1, Ping Hou2, Kurt H. Bockhorst2, Renjie He2, Ponnada A. Narayana2 1University of Houston, Houston, Texas, USA; 2University of Texas Medical School at Houston, Houston, Texas, USA

Synopsis: A method for automatic determination of the perfusion parameters based on dynamic susceptibility contrast MRI is proposed and applied to determine the hemodynamic parameters. Our algorithm is based on the singular valued decomposition (SVD) technique in which the thresholds are automatically determined. In addition, our algorithm automatically determines the arterial input function by searching the whole image volume. Application of this method to rodents yielded a value of the cerebral blood volume that is very close to the value determined using the microsphere technique, considered to be the “gold standard”.

Poster Sessions

317

Perfusion & Permeability: Dynamic Contrast Enhanced Methods Hall D Monday 14:00-16:00

1882. Comparison of Perfusion Analysis in DCE-MRI of Brain Tumors with and Without T1-Quantification Michael Ingrisch1, Steven Sourbron1, Karin Herrmann1, Maximilian Reiser1, Michael Peller1 1Klinikum Großhadern, Munich, Germany

Quantification of tissue perfusion and permeability parameters from DCE-MRI bolus-tracking data requires a measurement of the tracer concentration, which can be obtained from a measurement of pre-contrast tissue relaxation rate. This study compares the effect of T1-quantification on the perfusion parameters measured with DCE-MRI in brain metastases, to a simpler approach based on relative signal enhancement. Contrary to expectations, values of perfusion and permeability parameters are increased after T1-quantification. Simulations confirm that T1-quantification may introduce additional errors if the actual flip angle is not precisely known.

1883. Measuring Cerebral Blood Flow and Blood-Brain-Barrier Leakage with DCE-MRI at 3T Steven Sourbron1, Michael Ingrisch1, Axel Siefert1, Maximilian F. Reiser1, Karin Herrmann1 1Ludwig-Maximilian-University Munich, Munich, Germany

DSC-MRI measurement of perfusion and permeability in the brain suffers from serious quantification issues. Here we propose an alternative in the form of an optimized DCE-MRI protocol at 3T, and evaluate it using measurements in normal tissue and in brain tumors. Maps of CBF approach the quality of DSC-MRI images. AIF selection is straightforward, CBF in Grey Matter agrees with gold-standard values, and Extraction Flow can be quantified from the same data. We conclude that DCE-MRI at 3T provides a viable alternative to DSC-MRI for the quantification of cerebral perfusion and permeability in a wide range of applications.

1884. Correction of Partial Volume Effects in Plasma Time Curve for Tracer Kinetic Analysis in DCE-MRI RKS Rathore1, A Singh1, RK Gupta2, M Haris2, SK Verma1, A Purwar1, G Bayu1, MK Sarma1, J Singh1, S Agarwal1, DKS Rathore1 1Indian Institute of Technoloky, Kanpur, Kanpur, India; 2SGPGIMS, Lucknow, India

Tracer kinetic analysis of DCE-MRI data requires the plasma concentration time curve. The use of individually measured plasma curve (if accurately measured) has advantages over standard plasma curve as it improves accuracy of measurements. In a brain DCE-MRI data the partial volume effect (PVE) is the main problem in the measurement of accurate plasma curve. The automated AIF extraction method proposed here is similar to that described by Rijpkema et al., 2001 and Parker et al., 2006, but it additionally corrects for the PVE, and also does an automatic estimation of bolus arrival time (BAT) using PL model.

1885. Comparison of Arterial Input Functions Obtained from Unlabeled- And 14C-Labeled-Gadolinium-Diethylenetriaminepentaacetic Acid and Its Application in MRI Estimation of Blood-To-Brain Influx and Cerebral Microvascular Blood Space Kishor Karki1, 2, Tavarekere N. Nagaraja1, James R. Ewing1, 2, Joseph D. Fenstermacher1, Robert A. Knight1, 2 1Henry Ford Hospital, Detroit, Michigan, USA; 2Oakland University, Rochester, Michigan, USA

The arterial input function (AIF) of contrast agent (CA) is required to calculate blood-to-brain transfer constant (Ki) and cerebral microvascular blood volume (vD). We compared AIFs from MRI and quantitative autoradiography studies using identically prepared CAs viz., unlabeled- and 14C-labeled- gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA and Gd-[14C]DTPA, respectively) in a rat model of transient focal cerebral ischemia to test our hypothesis that the reconstructed AIF generated from Gd-[14C]DTPA can be used to correct MRI-derived estimates of Ki and vD. For the regions with a leaky BBB, the reconstructed MRI-AIF produced significantly lower values of Ki and vD than did the original.

1886. An MRI Estimate of Vascular Permeability in 9L Cerebral Tumor Agrees with Those of Quantitative Autoradiography James Russell Ewing1, 2, Tavarekere N. Nagaraja1, ramesh paudyal3, Hassan Bagher-Ebadian1, 4, Knight Robert1, Ledbetter Karyn1, Joseph D. Fenstermacher1 1Henry Ford Hospital, Detroit, Michigan, USA; 2Oakland University, Rochester, Michigan, USA; 3oakland University, rochester, Michigan, USA; 4Amir-Kabir University of Technology, Tehran, Iran

In 15 rats implanted with 9L tumor, the vascular transfer constant (K1 or Ktrans) was assessed by MRI means, and then, in a terminal experiment, by quantitative autoradiography (QAR). Essentially the same indicator, albumin, tagged with Gd in the MRI, and with 125I in the QAR, was used. The K1’s estimated by the two techniques were in agreement.

1887. Vascular Permeability to Gd-DOTA and USPIO in C6 and RG2 Rat Glioma Models Marine Beaumont1, 2, Benjamin Lemasson, 13, Régine Farion1, 2, Christoph Segebarth1, 2, Chantal Remy1, 2, Emmanuel Luc Barbier1, 2 1INSERM U836, Grenoble, France; 2Université Joseph Fourier, Grenoble Institut des Neurosciences, UMR_S836, Grenoble, France; 3Oncodesign Biotechnology, Dijon, France

DCE-MRI provides insight into vascular permeability of tumors. Typically, a contrast agent such as Gd-DOTA is used and data are analyzed using classical pharmacokinetic models to obtain microvascular parameters. For further characterization, intravascular contrast agent (USPIO) can be used to determine blood volume and vessel size index under stationary conditions. In view of eventually combining these two approaches into a single imaging protocol, we evaluated whether the USPIO remains intravascular during a DCE-MRI protocol. DCE-MRI experiments using Dotarem® and Sinerem® were therefore performed on two brain tumor models. The presence of macrophages, potential transporters of iron, was equally investigated.

Poster Sessions

318

1888. Quantitative Permeability MRI in Acute Ischemic Stroke: How Long Do We Need to Scan? Logi Vidarsson1, Fang Liu1, Brandy Moran1, David Mikulis2, Andrea Kassner1 1The Hospital for Sick Children and the University of Toronto, Toronto, Canada; 2The Toronto Western Hospital, Toronto, Canada

Dynamic T1-weighted MR permeability imaging with subsequent pharmacokinetic modeling, provides valuable information on blood-brain-barrier (BBB) integrity in acute ischemic stroke (AIS) and can lend insight into which AIS patients later develop hemmorrhage. However, the relatively long scan duration (5 min) is problematic in critically ill AIS patients. In this work we examine the effects of reducing scan time on quantitative permeability (KPS). Our results indicate that the uncertainty in permeability estimates increases as less and less data is used for analysis.

1889. Which Voxels Should Be Analysed in DCE-MRI Studies of Anti-Vascular/angiogenic Compounds? Chris J. Rose1, James P. O'Connor1, Brandon Whitcher2, Geoff J. Parker1 1The University of Manchester, Manchester, UK; 2GlaxoSmithKline, London, UK

This abstract describes a problem with the way that average Ktrans is often computed in the context of studies of anti-vascular/angiogenic compounds, provides a simple geometrical explanation, proposes a solution and compares the statistical power of tests based on the two methods. Tumours often have an enhancing rim, thought to correspond to increased angiogenic activity. In such cases, we found that a given statistical power can be achieved using a smaller sample size when computing a voxel-wise average Ktrans from the enhancing region only, compared to computing the voxel-wise average Ktrans from all tumour voxels.

1890. Quantifying Spatial Heterogeneity in Dynamic Contrast-Enhanced MRI Parameter Maps Chris J. Rose1, Sam Mills1, James P. O'Connor1, 2, Gio Buonaccorsi1, Caleb Roberts1, Yvon Watson1, Sha Zhao1, Brandon Whitcher3, Gordon Jayson2, Alan Jackson1, Geoff J. Parker1 1The University of Manchester, Manchester, UK; 2Christie Hospital NHS Trust, Manchester, UK; 3GlaxoSmithKline, London, UK

In DCE-MRI-based drug trials, each tumour voxel is summarised using model-free or tracer kinetic model parameters. The tumour is summarised by average parameter value, but this fails to capture heterogeneity information. Heterogeneity has been described using histograms (for example), but previous methods discard all spatial information. This may be important to the correct interpretation of the structure of DCE-MRI parameter maps. We have developed statistics that consider parameters’ values and spatial locations. We show that these are sensitive to known drug effects and may predict the grade of gliomas (which are determined in histology by spatial heterogeneity).

1891. Assessing Drug Effects by Comparing DCE-MRI Parameter Maps Using the Earth Mover's Distance Metric Chris J. Rose1, Heather Reynolds1, James P.B. O'Connor1, 2, Sue Cheung1, Yvon Watson1, Gordon Jayson2, Brandon Whitcher3, Geoff J. Parker1 1The University of Manchester, Manchester, UK; 2Christie Hospital NHS Trust, Manchester, UK; 3GlaxoSmithKline, London, UK

In DCE-MRI drug trials, current practice involves computing parameters such as Ktrans at each tumour voxel and then summarising the tumour by the median Ktrans value. The change in median values before and after treatment is used as a dissimilarity measure. Drug effects are often observed in particular locations within the tumour. Median Ktrans may be insensitive to these heterogeneous local changes as they neglect the spatial location of parameters. This abstract describes how drug effects can be assessed by using the cost of matching pre- and post-treatment parameter maps using the Earth Mover's Distance metric.

1892. Fusion of Dynamic Contrast Enhanced (DCE) Perfusion Metrics with DTI Metrics Results in Better Assessment of Corticospinal Tract Infiltration in Malignant Gliomas Rakesh K. Gupta1, Mohammad Haris1, Mazhar Husain2, Sanjay Verma3, Anup Singh3, Abhishek Yadav1, Nuzhat Husain2, Ram Kishore Singh Rathore3 1Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India; 2CSM Medical University, Lucknow, India; 3Indian Institute of Technology, Kanpur, India

Edema surrounding the malignant tumors is a morphological sign of tumor infiltration in the adjacent white matter. Diffusion tensor imaging has been used to differentiate the infiltrative white matter tract from the normal white matter tract. The Malignant gliomas have shown high value of cerebral blood volume (CBV), cerebral blood flow (CBF), permeability (ktrans) and leakage (ve). In the current study, we fused DTI indices maps with perfusion maps with a hypothesis that the perfusion maps when combined with DTI maps should able to separate the edematous region from infiltrating fibers which may not be possible alone on DTI.

1893. DCE-MRI for Assessment of Effects of Anti-Angiogenic Therapy: Comparison of the Transfer Constant (Ktrans) to Blood Permeability Derived by a Distributed Parameter Model Choon Hua Thng1, Tong San Koh2, Septian Hartono1, 2, Helmut Rumpel3, James Boon Kheng Khoo1, Albert Su Chong Low3, Ai Bee Ong4, Norita Sukri4, Bee Choo Tai5, Ross Soo4, Rod A. Humerickhouse6, Boon Cher Goh4 1National Cancer Centre, Singapore, Singapore; 2Nanyang Technological University, Singapore; 3Singapore General Hospital, Singapore; 4National University Hospital, Singapore; 5National University of Singapore, Singapore; 6Abbott Laboratories, North Chicago, Illinois, USA

Dynamic contrast enhanced MRI (DCE-MRI) with tracer kinetic modeling has been proposed as a biomarker of angiogenesis imaging. Generalized kinetic (GK) model and uptake integral approach are commonly used DCE-MRI models whose representative parameters are Ktrans and initial area under the signal-time curve (IAUC), respectively. The distributed parameter (DP) model is a DCE-MRI model that enables derivation of blood flow and capillary permeability-surface area product (PS) independently. We aim to study the DP model as an alternative method of angiogenesis assessment and correlate the above parameters to drug exposure and patient outcome in a Phase I anti-angiogenic trial.

1894. Effect of Image Acquisition Protocol on Vascular Parameter Estimates from DCE-MRI Liver Data Matthew R. Orton1, David J. Collins1, David J. Hawkes2, David Atkinson2, Martin O. Leach1 1Institute of Cancer Research, Sutton, UK; 2Univeristy College London, London, UK

Since the liver is a highly vascularised organ, accurate pharmaco-kinetic models for DCE-MRI liver data must include a plasma fraction. The temporal resolution of the acquired data must therefore be fast enough to allow this feature to be observed. This work assesses the impact on the vascular parameter estimates of acquiring two volumes per breath-hold in a liver imaging protocol instead of one.

Poster Sessions

319

Perfusion & Permeability: Dynamic Susceptibility Contrast Methods Hall D Tuesday 13:30-15:30

1895. Is PRESTO Advantageous for DSC-Perfusion MRI Using Local AIF Measurements Due to Crushing of Intravascular Signal? Egbert Jan Willem Bleeker1, M. A. van Buchem1, M. J.P. van Osch1 1Leiden University Medical Center, Leiden, Netherlands

Local arterial input functions have less dispersion and delay than an AIF selected in the vicinity of the MCA. Another advantage is that flow-territory specific AIFs are used for deconvolution. It has been shown previously, that for local AIF measurements it is optimal to select voxels located completely outside the arteries. It could therefore be argued that crushing of vascular signal would improve local AIF measurements. The current study investigated the possible advantage of PRESTO, which crushes the vascular signal, over non crushing sequences at different echo times.

1896. Determination of Artery Input Function in Dynamic Susceptibility Contrast MRI Based on Regions Around Arteries Segmented by Independent Component Analysis Sharon Chia-Ju Chen1, Keh-Shih Chuang1, Yuan-Yu Hsu2, Ho-Ling Liu3, 4 1National Tsing Hua University, HsinChu, Taiwan; 2Buddhist Tzu-Chi General Hospital-Taipei, Taipei, Taiwan; 3Chang-Gung University, Tao-Yuan, Taiwan; 4Chang-Gung Memorial Hospital, Tao-Yuan, Taiwan

Determination of arterial input function (AIF) is very critical in quantifying cerebral blood flow (CBF) in perfusion MRI study. Recent investigations suggest that the region of most T2* signal change during the passage of contrast agent is around vessels. Conventional region selection by hand drawing suffers from partial volume effect and cause error in the estimation of AIF. Independent component analysis (ICA) method decomposes signal into the interested source signal with alleviative partial volume effect. It provides more precise determination of AIF and quantification of CBF.

1897. DSC-MRI Perfusion Imaging: Which Input Function? – a Comparison to CT Perfusion Imaging Irene K. Mikkelsen1, Doerthe Ziegelitz2, Birgitte F. Kjølby1, Göran Starck2, 3, Arnold Skimminge4, Maria T. Widmark2, Mats Tullberg3, Stig Holtås5, Carsten Wikkelsø3 1Århus University, Århus, Denmark; 2Sahlgrenska University Hospital, Göteborg, Sweden; 3Göteborg University, Göteborg, Sweden; 4Copenhagen University Hospital, Hvidovre, Denmark; 5Lund University Hospital, Lund, Sweden

The choice of artery for input function (AIF) measurement in dynamic susceptibility contrast imaging (DSC-MRI) influences the cerebral blood flow estimates (CBF). The DSC-MRI has no simple correction scheme for partial volume effects, whereas this is easily corrected for with CT. This study investigates the correlation between DSC-MRI and CT perfusion values for a typical CT and MR input functions. It is demonstrated that the correlation between DSC-MRI and CT are moderate for absolute perfusion values whereas the correlation of the GM/WM CBF ratio between modalities follows the identity line.

1898. Does Deconvolution in DSC-MRI Deliver Bolus-Shape Independent Results, or Why Noise is the Limiting Factor in DSC-MRI? Matus Straka1, Rexford D. Newbould1, Gregory W. Albers1, Roland Bammer1 1Stanford University, Stanford, California , USA

In quantitative DSC-MR PWI, deconvolution was aimed to reduce dependency of computed perfusion parameter on bolus shape. Theoretically, deconvolution should deliver perfusion parameter estimates independent of signal shape, but noise present in data and low-pass filtering induced by regularization causes dependency of CBF estimates on shape of the AIF, tissue curves and impulse response function of the underlying brain tissue. The error due to AIF shape change possible in typical measurements was found to be 10% of the true CBF value (20% of the estimates). Further, causes and solutions for the problem are discussed.

1899. What is a Good Sampling Rate for DSC-MRI Brain Perfusion Measurements? Matus Straka1, Rexford D. Newbould1, Gregory W. Albers1, Roland Bammer1 1Stanford University, Stanford, California , USA

In quantitative DSC-MRI perfusion imaging, deconvolution process employs regularization to suppress noise-induced instabilities. Regularization therein has a strong low-pass filtering effect, hence removal of the high frequencies poses a question if a lower temporal resolution is acceptable as longer TRs are advantageous (less vessel signal clipping, more slices). Sampling at frequency related to the regularization cut-off leads to undesired changes due to spectrum aliasing, therefore sampling at higher frequency (related to spectra of signals and noise level) is proposed. Results confirm that sampling faster than necessary brings little benefit. For current MR PWI and noise, TR<2s might have no advantage.

1900. On the Optimal Injection Speed for Bolus Tracking Perfusion Peter Gall1, Irina Mader1, Birgitte Fuglsang Kjølby2, Valerij Kiselev1 1University Hospital Freiburg, Freiburg, Germany; 2Aarhus University Hospital, Aarhus, Denmark

The choice of an appropriate contrast agent injection speed and dosage is crucial for every DSC perfusion protocol. Contrast to noise (CNR) and temporal sampling are two competing measures for Gd-DTPA tracers. Simulations show that for typical bolus widths and sampling rates aliasing can occur. In order to avoid aliasing, CNR can be sacrificed by reducing the injection speed and therefore gain relative temporal resolution. The optimal injection setup was explored based on a study with 16 volunteers that underwent the measurement under different injection rates and dosages. The study shows that aliasing occurs for injection times smaller than 3*TR.

Poster Sessions

320

1901. Improved Deconvolution of Residue Function in MR Perfusion in the Presence of Bolus Delay and Dispersion Using Least-Absolute-Deviation Regularization Kelvin Wong1, Chi-Pan Tam2, Michael Ng2, Stephen T.C. Wong1, Geoffrey Young3 1The Methodist Hospital Research Institute, Houston, USA; 2Hong Kong Baptist University, Hong Kong, People's Republic of China; 3Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA

In this study, we report the development of a model-independent deconvolution technique using least-absolute-deviation (LAD) regularization to improve the CBF estimation accuracy in the presence of bolus delay and bolus dispersion. Monte Carlo simulations were performed to compare the accuracy of CBF estimates derived from LAD, reformulated SVD (rSVD) and standard SVD (sSVD). The LAD method resulted in more accurate and reproducible residue function calculation than either rSVD or sSVD methods from no dispersion up to 1s dispersion.

1902. A Novel Nonparametric Population Deconvolution for DSC-MRI Quantification: Assessment on Simulated Data Denis Peruzzo1, Gianluigi Pillonetto1, Alessandra Bertoldo1, Claudio Cobelli1 1University of Padova, Padova, Italy

A novel nonparametric population deconvolution algorithm (PD), for DSC-MRI images quantification, is proposed and validated on simulated data. PD allows to simultaneously estimate the residue functions R(t) taking advantage of the entire collection of measures obtained from pixels population.PD provides more accurate estimates of CBF values than SVD, especially with dispersed R(t). R(t) obtained by PD are very regular, without unphysiological oscillations and closer to true R(t) than those obtained by SVD. When applied on a population having a bimodal CBF distribution, PD still provides closer estimates of R(t) than SVD, but less accurate CBF values.

1903. Model Free Bolus Arrival Time Estimation for Dynamic Contrast MR Studies Arjan W. Simonetti1, Stefan Sunaert2, Ping Yang1, Arianne van Muiswinkel1 1Philips Medical Systems, Best, Netherlands; 2University Hospitals of the Catholic University, Leuven, Belgium

The estimation of bolus arrival time in dynamic MR data is relevant for clinical applications that rely on quantitative analysis like perfusion and permeability. We describe a method that uses the common lineshape of the MR signal intensity time curves and provides a sub-pixel correction of bolus arrival time. We show how this method can be used to select target pixels in arteries that may be used for arterial input function estimation and we show how relative bolus arrival time maps can be constructed.

1904. Comparison of an FT Based MMSE Method with OSVD Method for CBF Estimation in Patients with VCI Unal Sakoglu1, Branko H. Garate1, Gary Rosenberg1, Rohit Sood1 1University of New Mexico, Albuquerque, New Mexico, USA

PWI using bolus-tracking technique based on DSC MRI has been developed to assess blood flow parameters such as CBF, CBV and MTT. Data processing of the acquired MRI data involves computation based on one of the two widely used convolution methods, circular SVD based method (oSVD) and the FT based method. In this study, a modified FT based MMSE (Minimum Mean Squared Error) method, that was proposed earlier and implemented as a simulation, has been used to extract flow parameters from PWI in 9 patients with Vascular Cognitive Impairment (VCI) and the results are compared with the existing standard oSVD method. The flow results are reported as relative CBF values, which is the ratio of CBF (normal white matter (WM) to gray matter (GM) and WM lesions (WML) to GM). Initial results demonstrate a significant decrease in relative CBF in the WM lesions (p<0.05, paired, two-tail t-test, n=9) with the results being more significant for the FT based MMSE method.

1905. Using Dynamic Susceptibility Contrast MRI for Cerebral Perfusion While Studying Alzheimer's Disease Rachel DiAnne McKinsey1, Zhifei Wen2, Sterling Johnson, Alan McMcMillian1, Beth Meyerand2, Michele Fitzgerald, Cynthia Carlsson, Gemma Gliori, Sean B. Fain2 1University of Wisconsin Madison, Madison , USA; 2University of Wisconsin Madison, Madison, USA

The purpose of this study is to investigate the ability of DSC MRI with hybrid applications that combines bolus and infusion techniques to measure CBV and CBF changes in subjects with AD. Ten subjects with AD and ten Control Normal subjects were scanned on a GE Signa 1.5T MR. The statistical maps generated showed perfusion differences among AD and Control groups for CBV and CBF. Hypoperfusion was observed in both the Posterior Cingulate and thalamus for CBV and CBF. Other areas of decreased perfusion were caudate for CBV and posterior hippocampus for CBF. The data support DSC MRI as a viable means for measuring relative perfusion changes in AD.

1906. Modeling the Regulation of Cerebral Oxygen Extraction by Flow Heterogeneity Sune Nørhøj Jespersen1, Mahmoud Ashkanian1, Kim Mouridsen1, Leif Ostergaard1 1Aarhus University, Aarhus, Denmark

The normal heterogeneity of blood flow velocities within the capillary bed has been speculated to constitute a reserve capacity, by which the oxygen extraction fraction can be increased through homogenization of microvascular flows, even at constant cerebral blood flow. For example, homogenization of the capillary flow distribution has previously been shown to be associated with high risk of subsequent infarction in acute ischemic stroke. Here we develop and analyze a comprehensive framework relating flow heterogeneity to the oxygen extraction fraction from dynamic susceptibility contrast perfusion raw data, and present an initial validation of the approach by comparison to O15 PET.

1907. Investigation of Vascular-Space-Occupancy (VASO) MRI for Quantitative Measurement of Cerebral Blood Volume (CBV) Jinsoo Uh1, Kelly Lewis-Amezcua1, Rani Varghese1, Hanzhang Lu1 1University of Texas Southwestern Medical Center, Dallas, USA

Vascular-Space-Occupancy (VASO) MRI is a new method for measuring cerebral blood volume (CBV) in humans, but several confounding factors need to be understood to fully optimize the method for accurate measurement. We performed VASO experiments (n=9) and simulations to investigate the effects of confounding factors including transverse relaxation, capillary water-exchange, and the change of concentration of contrast agent. The results demonstrate that water exchange can cause over-estimation, and T2/T2* effects can cause under-estimation in VASO CBV measurement. A post-contrast scan between 5-15 min with a multiple-echo acquisition scheme is recommended for accurate estimation of absolute CBV.

Poster Sessions

321

1908. Quantification of Cerebral Blood Volume Changes in Response to a Visual Stimulus in Humans Nicholas P. Blockley1, Roman Wesolowski1, Susan T. Francis1, Penny A. Gowland1 1University of Nottingham, Nottingham, UK

It has previously been shown that dynamic changes in total cerebral blood volume (CBV), in response to a stimulus, can be monitored by using an infusion of contrast agent (CA). However this method only provides the percentage change in CBV. In this work we produce quantitative time-courses of CBV by integrating a DSC-MRI protocol into the existing paradigm. Rather than relying on a steadily increasing CA concentration provided by an infusion, here we rely on the exponential wash out of CA by the kidneys to measure the change in CBV. Pilot studies of this protocol were performed at 3.0 T and 7.0 T.

1909. Steady-State Relationship Between Cerebral Blood Flow and Venous Blood Volume J. Jean Chen1, G. Bruce Pike1 1McGill University, Montreal, Canada

Grubb’s power coefficient has been widely used to derive total cerebral blood volume (CBV) from cerebral blood flow (CBF), but knowledge of the relationship between venous CBV (δCBVv) and CBF is scarce, yet it is well established that the BOLD signal is mainly modulated by venous CBV. In this work, we used the venous refocusing for volume estimation (VERVE) technique to measure δCBVv. We derived the steady-state relationship between δCBVv and δCBF in human subjects using graded visual and sensorimotor stimulation. We obtained a venous-specific power-law coefficient of 0.26, significantly lower than Grubb’s estimate of 0.38.

1910. High Resolution MR Vessel Size Imaging Using Dual Contrast Agent Injections Wei-Shan Yang1, 2, Yuan-Yu Hsu3, Ho-Ling Liu1, 4 1Chang Gung University, Tao-Yuan, Taiwan; 2Cheng Hsin Rehabilitation Medical Center, Taipei, Taiwan; 3Buddhist Tzu Chi General Hospital, Taipei, Taiwan; 4Chang Gung Memorial Hospital, Tao-Yuan, Taiwan

Microvascular dimensions can be estimated by vessel size imaging (VSI) based on R2* and R2 measurements following bolus injection of contrast agents. VSI has been successfully applied in humans using a double-echo sequence which is however not widely available in clinical scanners and may be limited in spatial resolution. This study showed that VSI maps could be acquired with clinical sequences at 128x128 matrix during two separate dynamic contrast scans and the resulted vessel calibers agreed well with previously published data. Potential errors caused by temporal misalignment between two dynamic contrast scans were found within 8% based on computer simulation.

1911. Comparison of Susceptibility-Weighted Imaging and Tracer Kinetic Model Analysis in Brain Tumors Chun-Jung Juan1, Hua-Shan Liu1, 2, Hing-Chiu Chang3, Hsiao-Wen Chung2, Chao-Ying Wang1, Queenie Chan4, Nai-Yu Cho5, Cheng-Yu Chen1, Chun-Jen Hsueh1, Chung-Ping Lo1, Guo-Shu Huang1 1Tri-Service General Hospital, Taipei, Taiwan; 2National Taiwan University, Taipei, Taiwan; 3GE Healthcare Taiwan, Taipei, Taiwan; 4Philips Medical Systems, Hong Kong; 5National Yang-Ming University, Taipei, Taiwan

This study was designed to evaluate the blood oxygenation level dependency (BOLD)-based vasculature and angiogenic status with microvascular proliferation in brain tumors by using susceptibility-weighting imaging (SWI) and the first-pass pharmacokinetic (FPPM) model of T2* MR perfusion-weighted images. We compared SWI and FPPM images with supplementary information from conventional contrast-enhanced T1-weighted (CET1) imaging to find associated pathological condition of vascular hyperplasia occurred on tumor proliferations. The preliminary results of observation show that CET1 excelled in tumor boundary detection. SWI excelled in visualizing blood vasculature and the FPPM model of perfusion-weighted imaging is good at detection in internal architecture than SWI and CET1.

1912. Modeling T1 and T2 Effects of Contrast Agent Extravasation and Pre-Loading Dose in Dynamic Susceptibility Contrast MRI Yi-Ying Wu1, 2, Ho-Ling Liu1, 2 1Chang Gung University, Kwei-Shan, Taiwan; 2Chang Gung Medical Hospital, Kwei-Shan, Taiwan

Disruption of BBB in brain tumors can cause errors in perfusion measurements using DSC MRI. Such errors were mainly caused by T1 effects in slightly leaky conditions and may be corrected using existing models. This study proposed a two-compartmental model and both T1 and T2 effects were taken into account in the signal time curve. In addition, the effects of the pre-loading dose were incorporated in the model. This model was showed to agree well with the existing ones in slightly leaky conditions and be able to simulate the additional T2 effects in very leaky conditions.

1913. Optimizing DSC-MRI Acquisition Parameters to Minimize Extravascular T1 and T2* Effects Due to Contrast Agent Leakage: A Simulation Study C. Chad Quarles1, Sunil Narayan1, John C. Gore1, Thomas E. Yankeelov1 1Vanderbilt University, Nashville, Tennessee, USA

DSC-MRI methods for assessing tumors are confounded by the extravasation of contrast agent resulting in simultaneous changes in the EES T1 and T2* that can confound susceptibility-induced signal decreases and yield unreliable CBV and CBF measurements. A methodological study of these relaxation interactions has yet to be reported. This is of note since the DSC parameter estimates could be significantly affected by both physiological and pulse sequence parameters. In this contribution we perform a series of simulations in which we systematically vary relevant MRI pulse sequence and physiological parameters and assess the errors returned in CBF and CBV.

1914. Simultaneous Measurement of DSC- And DCE-MRI Parameters Using Dual-Echo Spiral with a Standard Dose of Gadolinium Eric Scott Paulson1, Douglas Edward Prah1, Kathleen Marie Schmainda1 1Medical College of Wisconsin, Milwaukee, USA

We demonstrate here that DSC and DCE parameters, both corrected for confounding contrast agent effects, can be obtained simultaneously using a dual-echo spiral acquisition with a standard dose of gadolinium.

Poster Sessions

322

1915. Contrast Agent Extravasation Correction Combined with Automated AIF Identification in DSC-MRI Qing Ji1, John O. Glass1, Wilburm E. Reddick1 1St.Jude Children's Research Hospital, Memphis, Tennessee, USA

We developed and implemented a simple and fast contrast agent leakage correction method in DSC perfusion MRI. In this method, the arterial input function (AIF) was first calculated from the perfusion MRI scan using a previously developed technique called iterative self-organizing map clustering technique. Then the AIF was directly used in a modified pharmacokinetic model to fit the concentration-time course in patient’s perfusion MRI scan. Because no extra parameters were introduced in the model, the fitting was fast. T2* weighted image data sets from fifteen pediatric brain tumor patients have been evaluated with this method. The results have demonstrated that both T1 and T2* effects caused by the contrast agent leakage can be corrected with this model.

Arterial Spin Labelling Methods Hall D Wednesday 13:30-15:30

1916. Comparison of Continuous Arterial Spin Labeling Perfusion MRI at 7T and 3T S. Lalith Talagala1, T-Q Li1, H. Merkle1, S. Wang1, J. Bodurka1, P. van Gelderen1, J Duyn1 1National Institutes of Health, Bethesda, Maryland, USA

This work compares continuous ASL (CASL) perfusion data at 7T and 3T on the same subjects using the same protocol. Good quality 7T CASL data, which compared very well with 3T data, were obtained from all subjects. The measured perfusion signal (range 1.3-1.6%) was similar at the two field strengths. The intrinsic SNR of the difference signal was 55-95% better at 7T compared to 3T. However, the temporal SNR of the difference signal (range 0.7-1.6) was similar at both fields. Results indicate that 7T CASL data may be further improved by optimization of labeling efficiency and reduction of signal fluctuations.

1917. Is It Possible to Achieve Sufficient Inversion Efficiencies in CASL Experiments at High B0 and Low B1 Field Strengths? Robert Trampel1, Thies H. Jochimsen2, Toralf Mildner2, Carol Docherty2, Harald E. Möller2, Robert Turner2 1Max Planck Institute for Human Cognitive and Brain Sciences , Leipzig, Germany; 2Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany

Perfusion imaging using magnetically labeled water is capable of measuring cerebral blood flow. As the signal-to-noise ratio increases with the main magnetic field strength B0 perfusion measurements at 7 T are expected to be more sensitive. For the quantification of perfusion, however, a reliable determination of the inversion efficiency α is required. A numerical method for predicting α under various conditions is demonstrated. At 7 T the specific absorption rate (SAR) limits the application of radio-frequency (RF) pulses. Therefore, we especially investigated whether it is possible to achieve sufficient inversion efficiencies in CASL experiments at high B0 and low B1 field strengths.

1918. Human Brain Perfusion MRI at 7T Using a Segmented True FISP ASL Method Elan J. Grossman1, Ke Zhang1, Jing An2, Yulin Ge1, Jian Xu3, Qun Chen1 1New York University, New York, New York, USA; 2Siemens Medical China, Beijing, People's Republic of China; 3Siemens Medical USA, Malvern, Pennsylvania, USA

Ultra-high field (7T) MR imaging should benefit ASL methods due to increased SNR and longer T1 relaxation times. Here we assess the use of true FISP ASL as a feasible alternative to EPI-based methods of perfusion imaging at 7T. Preliminary results show that this sequence is capable of measuring local tissue perfusion in human brain at 7T with high spatial resolution and without the distortion artifacts commonly identified with EPI-based methods of ASL, although banding artefacts associated with true FISP imaging can sometimes degrade image quality.

1919. Hippocampal Blood Flow and Vascular Reserve: TrueFisp ASL at 3T Henry Rusinek1, Miroslaw Brys, Remigiusz Switalski, Francois Haas, Kellyanne Mcgorty, Mony de Leon, Qun Chen 1NYU School of Medicine, New York, New York, USA

We have developed and tested a protocol based on segmented true FISP to measure regional cerebral blood flow (rCBF) in the hippocampal region of 12 young normal volunteers. The measurements were repeated during the carbon dioxide challenge achieved with a rebreathing technique. Baseline rCBF were 79.4±16.7 ml/100g/min in the right and 84.3±21.9 in the left hippocampus. During CO2 challenge, rCBF increased to 96.2±19.2 in the right and 98.5±22.9 in the left hippocampus. The technique is relatively quick and easily repeatable, which may be of particular importance in research on Alzheimer’s disease, epilepsy, and other neurological disorders of medial temporal lobe.

1920. Effects of CBV and Capillary Permeability on ASL Signal Changwei Wesley Wu1, 2, Jyh-Horng Chen2, Yihong Yang1 1National Institute on Drug Abuse, Baltimore, Maryland, USA; 2National Taiwan University, Taipei, Taiwan

Although the arterial spin labeling (ASL) has been utilized to measure cerebral blood flow (CBF) for decades, none of the existing models considered the effects of cerebral blood volume (CBV) change on CBF quantification. In this study, the contributions of CBV and capillary permeability on the pulsed ASL signal were investigated using a two-compartment (2-comp) model. Results show that these physiological effects might induce up to 8% ASL signal change. CBV effect might have more influence on the estimated perfusion in animal models, while permeability might have more effect on human subjects.

1921. Reliability and Reproducibility of Perfusion MRI in Elderly Control Subjects Li Jiang1, 2, Mina Kim1, 2, BettyAnn Chodkowski1, Manus J. Donahue1, 2, James J. Pekar1, 2, Peter C.M. Van Zijl1, 2, Marilyn Albert2 1Kennedy Krieger Institute, Baltimore, Maryland, USA; 2Johns Hopkins Medical Institution, Baltimore, Maryland, USA

Intraclass correlation coefficients (ICC) and within-subject variation coefficients (WSC) were used to estimate reliability and reproducibility of pulsed arterial spin labeling (ASL) MRI. Twelve elderly healthy subjects were scanned four times during one year. The first two scans were processed by two raters, the results of which showed high reliability (ICC>0.96) and reproducibility (WSC <0.01). However, over the total period of one year, reliability reduced (ICC = 0.59~0.68) while the reproducibility still remained high (WSC < 0.08). It was also found that the coefficient of random noise increased to greater than 0.24, which limited the reliability of perfusion measurements.

Poster Sessions

323

1922. Regional CBV Characteristics in Normal Subjects and Its Relation to CBF: A VASO and ASL MRI Study Sina Aslan1, Jinsoo Uh1, Perry Mihalakos1, Binu Thomas1, Carol Tamminga1, Hanzhang Lu1 1UT Southwestern Medical Center, Dallas, Texas, USA

CBF and CBV are important physiological parameters associated with neuronal activity measured by ASL and VASO MRI, respectively. In this study, we provide a reference aCBV for normal humans during resting state in four major cerebral lobes: temporal>occipital> parietal>frontal, 4.46±0.55 > 3.89±0.76 > 3.07±0.45 > 2.85 ± 0.46, respectively. Additionally, the relationship between CBF and CBV was examined using exponential model, CBV=0.778*CBF0.497. These results suggest CBV values could be used as a reference biomarker to provide prognosis and diagnosis. Furthermore, CBV can be calculated when CBF is known by using exponential model.

1923. Effects of Pulsatile Flow on Arterial Input Function and CBF Quantification in Continuous ASL Tsukasa Nagaoka1, Xiaodong Zhang1, Robbie Champion1, Govind Nair1, Yoji Tanaka1, Thimothy Q. Duong1 1Emory University, Atlanta, Georgia, USA

CBF is quantified by arterial input function (AIF) and the regional distribution of the tracer. However, AIF on ASL is calculated assuming an arbitrarily shaped AIF without considering pulsatile flow profiles. In this study, we simulated the effect of different flow profiles on the AIF. This model was applied to the arterial ASL signals obtained at different post-labeling delays with and without diffusion gradients in anesthetized monkey. We estimated the potential errors in CBF quantification due to flow dynamics over wide ranges of physiological and MRI measurement parameters.

1924. Distribution of Arterial Transit Times Investigated by MATISSE Toralf Mildner1, Karsten Müller1, Stefan Hetzer1, Robert Trampel1, Wolfgang Driesel1, Derek V.M. Ott1, D. Yves von Cramon, 12, Harald E. Möller1 1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; 2Max Planck Institute for Neurological Research, Cologne, Germany

Mapping of Arterial Transit times by Intravascular Signal SElection (MATISSE) is introduced as an approach to map the distribution of arterial transit times, a, in the human brain. The method is based on a smooth modulation of the efficiency of CASL between subsequent repetitions, and on the application of a

short repetition time. Under these conditions, the difference in a between two brain regions can be measured directly by evaluating the phase shift between the corresponding perfusion-weighted time series. CASL was performed by a separate labeling coil at the neck. The smooth modulation of the efficiency of CASL was achieved by changing the frequency offset of the labeling radiofrequency stepwise from repetition to repetition. It is demonstrated that MATISSE yields whole-brain a difference maps which are consistent with respect to the vascular territories of the human brain.

1925. Comparison Between Pseudo-Continuous and Separate Labeling Coil in Continuous Arterial Spin Labeling Hesamoddin Jahanian1, Tiffany M. Love1, Gregory R. Lee2, Luis Hernandez-Garcia1 1University of Michigan, Ann Arbor, USA; 2Case western reserve University, Cleveland, USA

Perfusion based functional MRI through Arterial Spin Labeling (ASL) has remarkable potential as a tool to study brain function because of its quantifiable nature and close relation to neuronal activity. Many techniques have been developed to increase the sensitivity of ASL perfusion MRI. Continuous labeling techniques (CASL) offer SNR advantages over pulsed labeling techniques (PASL). In this study, we compare two continuous labeling schemes in terms of their success in improving the SNR and their activation detection efficiency in vivo: flow driven adiabatin inversion using a separate labeling coil (Double coil CASL)and pseudo-continuous inversion (pCASL).

1926. Simultaneous Quantification of Cerebral Blood Flow and In-Vivo T2 and T2* of Cerebral Blood Using Continuous Arterial Spin Labeling Guangping Dai1, Jie Lu2, 3, Yasu Egi2, Eng H. Lo2, Young Ro Kim1 1A.A. Martinos Center/MGH, Charlestown, Massachusetts, USA; 2Neuroprotection Research laboratory/MGH, Charlestown, Massachusetts, USA; 3Xuanwu Hospital, Beijing, People's Republic of China

A new pulse sequence has been developed for quantifying in vivo intravascular blood oxygenation level dependence (BOLD) signal using continuous arterial spin labeling (CASL). Specifically, we have measured in-vivo T2 or T2* values of rat cerebral blood using the TE dependence of cerebral blood flow (CBF) signals obtained by CASL. With the transition of inhaled gas from air and 100% oxygen, we have demonstrated that our measurement scheme can be used for reliably quantifying the CBF and in vivo T2 and T2* changes of cerebral blood.

1927. Quantitative Perfusion Imaging Using Q2TIPS-FAIR PROPELLER EPI Huan Tan1, Craig A. Hamilton1, Robert A. Kraft1 1Wake Forest University School of Medicine, Winston-Salem, USA

Perfusion imaging of the brain is greatly affected by subject motion and off-resonance effects. PROPELLER is an advanced imaging technique that is less sensitive to both motion artifacts and magnetic field inhomogeneity. We have implemented the Q2TIPS-FAIR PROPELLER EPI sequence that produced quantitative cerebral blood flow maps with improved image quality and spatial resolution.

1928. PASL Filtering: A Method of Improving Clinical Perfusion Imaging Huan Tan1, Joseph A. Maldjian1, Jonathan H. Burdette1, Andrew R. Deibler1, Jeffrey M. Pollock1, Robert A. Kraft1 1Wake Forest University School of Medicine, Winston-Salem, USA

Arterial spin labeled MR imaging is a powerful method for quantitatively measuring cerebral perfusion. We have implemented ASL as a routine part of the clinical MR evaluation, acquiring 3500 cases over a 10-month period. In a small, but significant number of these cases, the data is uninterpretable, largely due to excess patient motion and system instability. We have implemented a post processing filter which can recover the perfusion signal in many of these previously uninterpretable cases.

Poster Sessions

324

1929. A Systematic Approach to Optimizing Background Suppression for Arterial Spin Labeling Perfusion Imaging Nasim Maleki1, Weiying Dai2, David C. Alsop2 1University of Toronto, Toronto, Canada; 2Beth Israel Deaconess Medical Ctr, Boston, Massachusetts, USA

In this paper a systematic approach to optimizing background suppression for pulsed and continuous perfusion imaging is reported. We describe an algorithm to solve a nonlinear optimization problem with bounds on the pulse timings in order to decrease the background static signal for a broad range of T1s. Results of the optimization were added to pseudo-continuous ASL sequence and validated both in phantoms and in brain perfusion imaging in healthy subjects. Greater than 100 fold decrease in background signal intensity was successfully achieved such that the ASL signal change exceeded the residual signal from static tissue.

1930. Comparison of Pulsed Arterial Spin Labeling Sequences Using Different Absolute Quantification Methods Mustafa Cavusoglu1, Kamil Ugurbil1, 2, Kamil Uludag1 1Max-Planck-Institute for biological Cybernetics, Tuebingen, Germany; 2Radiology, Minnesota, USA

Three different ASL schemes (Q2TIPS, FAIR-QUIPSSII and PICORE-QUIPSSII with asymmetric BASSI pulses) were compared measuring absolute cerebral blood flow (CBF) in the human brain at 3T. Signal-to-noise ratios (SNR), magnetization difference between control and tag images and three different absolute CBF quantification schemes were evaluated. For identical sequence parameters and voxels, it was found that a) FAIR-QUIPSSII has the highest SNR b) FAIR-QUIPSSII yields slightly higher CBF values c) absolute CBF values depend on the quantification scheme utilized. One possible explanation for the findings is that effective labeling efficiency and physiological noise contamination are different for the tagging procedures used.

1931. Variable-Density Spiral Improves Quality of Multi-Shot Arterial Spin Labeling Perfusion Images Eric Scott Paulson1, Douglas Edward Prah1, Kathleen Marie Schmainda1 1Medical College of Wisconsin, Milwaukee, USA

By oversampling the center of k-space with each interleaf, variable-density spirals offer increased immunity against motion as well as facilitate self-navigated phase correction. We demonstrate here that variable-density spiral readouts improve the quality of multi-shot ASL perfusion images in brain.

1932. Quantification of Retinal Blood Flow Using a Pseudo-Continuous Arterial Spin Labeling Technique Nasim Maleki1, Weiying Dai2, 3, David C. Alsop2, 3 1University of Toronto, Toronto, Canada; 2Beth Israel Deaconess Medical Ctr, Boston, Massachusetts, USA; 3Harvard Medical School, Boston, Massachusetts, USA

Measurement of perfusion to the retina has implication in the assessment of many important disorders of retinal vascular supply and growth which could lead to blindness. In this paper, we applied a pseudo-continuous arterial spin labeling technique to quantify the blood flow of the retina using multiple delay times, 3 Tesla imaging, and 8-channel phased array head coil on healthy subjects. The results of this study establish the feasibility of imaging and quantification of blood flow to the retina with contrast free MRI in humans and may also provide a unique window for the study of choroidal blood flow control and pathology.

Animal Models & Cerebral Ischemia Hall D Thursday 13:30-15:30

1933. Longitudinal MRI for the Detection of a Typical Pattern of Cerebral Blood Flow (CBF) and Tissue Integrity Changes After Stroke in Ischemia Tolerant Rats Susanne Wegener1, Tommy Shute1, Eric C. Wong1 1University of California San Diego, La Jolla, USA

One of the unresolved problems in stroke therapy is the heterogeneity of the disease and of the individual resistance to ischemic damage. We used longitudinal MRI to study ischemia tolerance, induced in rats by preconditioning with 3-nitroproprionic acid (3NPA). When preconditioned rats were subjected to transient ischemia, the immediate deficit on apparent diffusion coefficient maps was dramatically reduced within 30min of occlusion, together with better maintained residual blood flow (CBF) in the ischemic area compared to controls. Besides, CBF was lower on the unaffected side in NPA animals. MRI might have the potential to detect a “signature” of ischemia tolerance.

1934. The Relationship Between Perfusion and Diffusion Imaging Parameters in Ischemic Stroke Qiang Shen1, Meghana Bhatta1, Ryan Jessee1, Timothy Q. Duong1 1Emory Unviersity, Atlanta, Georgia, USA

Ischemic stroke occurs when cerebral blood flow (CBF) falls below a critical threshold, resulting in energy failure which subsequently manifests into a reduction in the water apparent diffusion coefficient (ADC). However, how the ADC is affected by CBF over time and under different ischemic conditions remains poorly understood. In this study, ADC and CBF in rat models following permanent and transient (30-min, 60-min and 90-min) MCAO were systematically studied at multiple time points after stroke. These results provide novel insight into the relationship between ADC and CBF under different ischemic durations and time after stroke.

1935. Postischemic Hyperperfusion: The Insight from a Multi-Parameter MRI Study Qiang Shen1, Hanh Nguyen1, Timothy Q. Duong1 1Emory Unviersity, Atlanta, Georgia, USA

We investigated postischemic hyperperfusion in rats subjected to three different occlusion durations. Diffusion, perfusion and T2 imaging during acute and sub-acute phase were acquired. Hyperperfusion was observed predominantly in the core after 24 hrs post-occlusion in the 30-min MCAO group, some in the 60-min group, and none in the 90-min group. No hyperperfusion was observed in normal tissues. Tracking tissue fates indicates that subsequently salvaged tissue has normal CBF (no hyperperfusion) whereas tissue destined to infarct showed hyperperfusion. These results suggest that chronic phase hyperperfusion is due to changes in blood-brain permeability which leads to increased CBF in infarct regions.

Poster Sessions

325

1936. Effects of Blood-Brain Permeability on CBF Measured by Arterial Spin Labeling and Dynamic Susceptibility Contrast Yoji Tanaka1, Tsukasa Nagaoka1, Govind Nair1, Timothy Q. Duong1 1Emory University, Atlanta, Georgia, USA

Stroke disrupts blood brain barrier, resulting in changing vascular permeability which is expected to affect cerebral blood flow (CBF) quantification. However, permeability changes are generally not taken into account in perfusion imaging of stroke. The aim of this study is to examine how changes in permeability affect CBF measured by arterial-spin-labeling and dynamic-susceptibility-contrast MRI on the same animals under different experimental conditions which included stroke, hypercapnia and permeability disruption by mannitol. We concluded that permeability changes markedly affects the CBF, it affects the two methods very differently, and CBF MRI of stroke needs to take permeability changes into account.

1937. Comparison of Ischaemic Lesion Evolution Using Diffusion and Perfusion Imaging in the Shrsp RAT and WKY RAT Following Permanent Middle Cerebral Artery Occlussion (MCAO) Chris McCabe1, William Matthew Holmes1, Lindsay Gallagher1, Willy Gsell2, Anna F. Dominiczak1, Barrie Condon1, I Mhairi Macrae1 1University of Glasgow, Glasgow, UK; 2Imperial College London, London, UK

In the present study we investigated the spatiotemporal evolution of stroke in the SHRSP rat and compared this to its normotensive control the WKY rat. We have demonstrated that the SHRSP rat has significantly less penumbral tissue than the WKY within 1 hour of stroke onset and by 6 hours the SHRSP has no diffusion/perfusion mismatch. These results could have important implications for the management of stroke patients with pre-existing hypertension and suggest ischaemic damage could progress at a faster rate in the presence of known risk factors such as hypertension.

1938. Differential Spatio-Temporal Cerebral Blood Volume Response to Normobaric Oxygen Therapy in an Experimental Rat Stroke Model Ona Wu1, Jie Lu1, Yasu Egi1, Guangping Dai1, Yoshi Murata1, Joseph B. Mandeville1, John J. Marota1, A Gregory Sorensen1, Rick M. Dijkhuizen2, Kenneth K. Kwong1, Eng H. Lo1, Aneesh Singhal3 1Massachusetts General Hospital, Charlestown, Massachusetts, USA; 2University Medical Center Utrecht, Utrecht, Netherlands; 3Massachusetts General Hospital, Boston, Massachusetts, USA

In rodent and pilot human acute stroke studies, normobaric oxygen therapy (NBO, or inhaled 100% oxygen) transiently improved neurological deficits and diffusion-weighted imaging abnormalities. We used serial MRI in rodent stroke models to investigate the hemodynamic effects of NBO in different brain regions. NBO induced an early, reproducible change in cerebral blood volume Δ CBV) in different brain regions, with ‘salvageable’ tissue showing increased CBV. This effect diminished over 3 hours. Whether this effect indicates a mechanism (e.g a hemodynamic “reverse steal phenomenon”) or a consequence of ‘salvaged’ tissue requires further investigation.

1939. Vasculature Changes Early After Stroke Using One-Hour MCAo Mouse Model at 9.4T Shuning Huang1, Dmitriy Atochin2, Guangping Dai2, Paul Huang2, Bruce R. Rosen2, Young Ro Kim2 1MIT/MGH, Cambridge, Massachusetts, USA; 2MGH, Charlestown, Massachusetts, USA

Restoration of cerebral blood supply at early stage of stroke is critical for salvaging brain tissues at risk. We characterized vascular transformation during the reperfusion phase of transient ischemia using steady-state intravascular contrast agent techniques. Previous studies have shown that relative cerebral blood volume (rCBV) measured from Δ R2 and Δ R2*, the transverse relaxation rate change before and after the contrast agent administration, reflects total and micro-vascular CBV. The goal of this study was to understand cerebrovascular changes (rCBV and vessel size) in transient stroke mouse models using an intravascular contrast agent (superparamagnetic iron oxide nanoparticles) at 9.4T.

1940. Diffusion and Extracellular Space Volume in the Rat Somatosensory Cortex During Recovery from Transient Global Ischemia/hypoxia Ivan Vorisek1, 2, Norbert Zoremba3, Ales Homola1, 2, Karel Slais1, 2, Eva Sykova1, 2 1Institute of Experimental Medicine ASCR, Prague, Czech Republic; 2Charles University, 2nd Medical Faculty, Prague, Czech Republic; 3University Hospital RWTH Aachen, Aachen, Germany

The aim of the present study was to quantify the changes in ECS diffusion parameters during recovery from transient ischemia by TMA+-diffusion and MRI measurements and to describe their time course. The data were correlated with the results of DC-potential recordings and measurements of extracellular potassium levels. To the best of our knowledge, the diffusion parameters of the ECS during recovery from transient ischemia have not yet been studied in vivo.

1941. MRI/MRS of Ischemic Evolution in Mouse Brain at 14.1 T Hongxia Lei1, 2, Carole Berthet3, Lorenz Hirt3, Rolf Gruetter1, 4 1Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland; 2University of Lausanne, Lausanne, Switzerland; 3Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland; 4University of Geneva, Lausanne, Switzerland

High magnetic fields increase sensitivities and thus using a recently installed 14.1 T/26cm MR system, we sought to determine the feasibility of studying lesion developing and neurochemical changes following 30 min of ischemia in mouse brain. At 8 and 24h after the insult, T2-weighted images presented lesion developing and localized spectra were obtained with 0.035ppm linewidths in the stroke region after B0 homogenneities adjustment with 2nd-order shimming. Prominent changes include a transient doubling of brain Gln, postulated to reflect Glu excitotoxicity, and decreases in several compounds such as NAA, Glu, Tau, as well as increases in acetate (attributed to NAA breakdown) and Lactate.

Poster Sessions

326

1942. Radiation Pretreatment Result in a Dramatic Increase in ADC After Ischemic Brain Injury in Rats Elena Titova1, Arash Adami1, Robert Ostrowski1, Serafin Lalas1, Roman Vlkolinsky1, John H. Zhang1, Gregory Nelson1, Andre Obenaus1 1Loma Linda University School of Medicine, Loma Linda, California , USA

Radiation is routinely used in general medical practice significantly increases risk of stroke among patients but the response of the brain after such kind of injury is still insufficiently studied. We report that a single radiation (8Gy) exposure at 10 days prior to middle cerebral artery occlusion appears to reduce cytotoxic edema but dramatically increased ADC values at later time points. Thus, stroke outcomes in previously irradiated patients differ from the normal population and relatively low doses of radiation result in less brain edema in acute stages.

1943. White Matter Injury in Neonatal Rats After a Mild Cerebral Hypoxic- Ischemic Insult: MR Confirmation Prior to Assessment of Injury Markers Ursula I. Tuor1, 2, Min Qiao1, Sanju Lama2, Salma Shivji2, Kumud Deka2, Tadek Foniok1 1National Research Council - Institute for Biodiagnostics (West), Calgary, Canada; 2University of Calgary, Calgary, Canada

We hypothesized that mild cerebral hypoxia-ischemia producing selective white matter injury would have accompanying markers of injury in white matter reflecting mechanisms of damage. T2 MRI was used in our mild model of cerebral hypoxia-ischemia to screen animals with relatively selective white matter injury. In such animals, substantial white matter injury appeared irreversible as demonstrated by an increased labelling of cells with TUNEL and a reduced myelination detected with O4 and MBP. Inflammatory responses associated with microglia activation (ED1) were observed selectively in the whiter matter at 48hrs post a mild hypoxia ischemia.

1944. Effect of Gender on Cerebral Hypoxic-Ischemic Injury in Neonatal Brain: a Magnetic Resonance Imaging Perspective Sanju Lama1, 2, Min Qiao2, Tadek Foniok2, Ursula I. Tuor, 12 1University of Calgary, Calgary, Canada; 2National Research Council Institute for Biodiagnostics (West), Calgary, Canada

In adults, stroke injury is affected by gender. We hypothesized that neonates would also exhibit gender-differences in the extent, distribution or degree of vasogenic edema detected with MRI following cerebral hypoxia-ischemia. Seven day old rats were subjected to cerebal hypoxia-ischemia and T2 imaging to determine infarct size and edema. Three days post insult, the ischemic lesion volume was similar in male and female pups, however, T2 values in ischemic parietal cortex were less in female than male rat pups. The greater edema in males supports a sexual dimorphism regarding the mechanisms of hypoxic-ischemic injury in immature brain.

1945. Cerebral Reorganization After Transient Focal Ischemia in Developing Rat Brain Chrystelle Po1, Sebastien Fau2, Christiane Charriaut-Marlangue2, Philippe Meric1, Brigitte Gillet1 1ICSN/CNRS, Gif-sur-Yvette, France; 2UMR-CNRS 7102, Paris, France

The evolution of the injured tissues after a transient focal cerebral ischemia in neonate rats was investigated by serial measurements of T2 maps and DTI. Since day 7 after ischemia up to day 21, a significant low T2 value area on T2 maps and significant perturbations of tissue organization evidenced on maps of anisotropy fraction and of first eigenvector of DTI appeared in the previously ischemic area. At day 21, this area correlated with a significant increase of cell density on corresponding cresyl-violet stained brain slices suggesting that these data reflect tissue healing processes such as gliosis.

1946. Tissue Water Dynamics in Acute Ischemic Stroke by T1ρ and T2ρ MRI Using Adiabatic Pulses Kimmo Jokivarsi1, Juha-Pekka Niskanen1, 2, Heidi Gröhn3, Shalom Michaeli4, Michael Garwood4, Risto A. Kauppinen5, Olli H. Gröhn1 1A.I.Virtanen Institute for Molecular Sciences, Kuopio, Finland; 2University of Kuopio, Kuopio, Finland; 3Kuopio University Hospital, Kuopio, Finland; 4University of Minnesota, Minneapolis, Minnesota, USA; 5Dartmouth Medical School, Hanover, New Hampshire, USA

Rotating frame relaxation obtained with adiabatic pulses allows for the contribution of dipolar interactions and exchange effects to be modulated by changing amplitude and phase modulation of the RF pulses. Using a known two-site exchange model the inherent correlation times, population sizes and exchange correlation times can be computed. We investigated the water dynamics during evolving cerebral ischemia in a rat permanent stroke model. Our results show that both adiabatic T1 ρ and T2 ρ MRI reveal cerebral ischemia early on. Changes in fitted exchange parameters are indicative of increase in free water content and lytic damage to tissue.

1947. Differentiating the Early Stage Ischemic Stroke Severity in Mice Using Diffusion Tensor Imaging Tzy-Haw Wu1, 2, Hsiao-Fang Liang2, Chin-I Chen, 23, Chung-Yi Hsu4, Sheng-Kwei Song2 1National Taiwan University Hospital, Taipei, Taiwan; 2Washington University School of Medicine, St. Louis, Missouri, USA; 3Taipei Medical University - Wanfang Municipal Hospital, Taipei, Taiwan; 4Graduate Institute of Neuroscience, Taipei Medical University, Taipei, Taiwan

SynopsisWe generated a mouse stroke model to determine if DTI can differentiate the different severities of ischemic stoke in the early stage. In this study, the areas of infarcted cortex and external capsule (EC) were evaluated by DTI. The result showed that axial diffusivity and radial diffusivity in the area of infarcted EC are statistically different among the three ischemic stroke groups of different severities. The infarcted cortex volume increases with the increased severity of stroke. ADC values in the infarcted cortex are not as sensitive as axial diffusivity or radial diffusivity in the area of infarcted EC. The DTI predicted axonal injury in EC was also validated by immunohistochemistry. In conclusion, DTI provides a good quantitative measure to evaluate the severity of early stage ischemic stroke in mice, especially the measurement in the area of infarcted EC.

Poster Sessions

327

Imaging in Stroke: Clinical Studies Hall D Monday 14:00-16:00

1948. Biomarkers of Cerebral Microvascular Angiopathy in Healthy Subjects at Risk of Stroke Alan Jackson1, Johann Selvarajah2, Marietta Scott3, Sharon Hulme3, Rachel Georgiou3, Nancy Rothwell3, Pippa Tyrell4 1University of Manchester, Withington, UK; 2Greater Manchester Neuroscience Centre, Salford, UK; 3University of Manchester, Manchester, UK; 4Greater Manchester Neuroscience Centre, Manchester, UK

We have examined 2 imagign biomarkers of cerebral microvascular disease in normal elderly subjects at risk of stroke. Both dilated Virchow Robin Spaces and Arterial-CSF pulsewave propogation rates were significantly different in subjects at risk and subjects not at risk whilst white matter lesion distribution was not significantly different.

1949. Detection of Crossed-Cerebellar Hypoperfusion in Acute Stroke Using Perfusion-Weighted MRI Jonathan T. Kleinman1, Doris D.M. Lin1, Robert J. Wityk1, Rebecca F. Gottesman1, Andrew W. Lee1, Peter B. Barker1 1Johns Hopkins University, Baltimore, Maryland, USA

Crossed cerebellar diaschisis (CCD) is commonly reported in the nuclear medicine literature in studies of acute stroke. This abstract reports on the incidence of CCD (hypoperfusion) in acute stroke as detected by MR perfusion imaging.

1950. Correlation of Acute Perfusion Lesion Volumes with Neurological Deficits Depends on Deconvolution Algorithm Ona Wu1, Jie Lu1, Vicky J. Tiglias1, Christian A. Holt2, Thomas Benner1, William A. Copen2, E Murat Arsava1, Hakan Ay1, Pamela W. Schaefer2, R Gilberto Gonzalez2, Lee H. Schwamm2, Aneesh B. Singhal2, A Gregory Sorensen1 1Massachusetts General Hospital, Charlestown, Massachusetts, USA; 2Massachusetts General Hospital, Boston, Massachusetts, USA

A consecutive series of acute stroke patients who received PWI<12h of stroke onset was retrospectively studied (N=144) to determine whether the extent of correlation of PWI maps with neurologic deficits depends on deconvolution algorithm. Lesion volumes on perfusion maps calculated using truncated standard singular value decompositions (sSVD) was compared with PWI maps generated using a delay-insensitive technique (oSVD). oSVD was found to produce maps that correlated better with acute and follow-up neurological deficits than sSVD. oSVD produced maps that also better corresponded with follow-up lesion volumes in patients not given thrombolytic therapy.

1951. Acute Middle Cerebral Artery Stroke - Comparison of Haemodynamic Timing Properties Assessed by Dynamic Contrast-Enhanced Perfusion Measurement and Arterial Spin Labeling Johannes Gregori1, 2, Achim Gass1, 3 1Klinikum Mannheim, Universität Heidelberg, Mannheim, Germany; 2mediri GmbH, Heidelberg, Germany; 3Universitätsspital Basel, Basel, Switzerland

Dynamic Susceptibility Contrast (DSC) imaging and Arterial Spin Labeling (ASL) yield different basic timing properties – e. g. time to peak (TTP) in DSC and bolus arrival time (BAT) in ASL - which give different measures of the same underlying haemodynamic mechanisms. While the temporal resolution of DSC is limited to 1-2 seconds, ASL time series can in principle be acquired in arbitrarily small intervals.Reliable assessment of haemodynamics is crucial in acute stroke - especially penumbral areas are of major interest. In this work we present a comparison of BAT and TTP maps for cases of acute middle cerebral artery stroke. Focus is layd on arterial inflow delay differences on a sub-second scale which are difficult to assess by DSC imaging.

1952. Does Arterial Spin Labeling Have a Role in Stroke Imaging? Preliminary Results from a 180 First Time Stroke Patients Study Esben Thade Petersen1, Amandine Cheze1, Violet Chua1, N V. Ramani1, Robert Ngo Gan1, Xavier Golay, 12 1National Neuroscience Institute, Singapore, Singapore; 2Singapore Bioimaging Consortium, Singapore, Singapore

Arterial Spin Labeling suffers from an inherently low signal-to-noise ratio which necessitates averaging and therefore relative long scan times, making the technique prone to motion artifacts. In addition, the white matter signal is at the sensitivity limit and it is often debatable whether ASL can contribute to stroke imaging at all. In this work, we compare information obtained with standard gadolinium-based perfusion methods to that obtainable using arterial spin labeling techniques. Comparable CBF and timing information was demonstrated with both techniques, while ASL delivered additional information on collateral perfusion which plays an important role in patients with cerebral artery occlusion.

1953. Added Combined Value of Pulse Arterial Spin Labelling (PASL) and Susceptibility Weighted Imaging (SWI) in Cerebral Vascular Occlusion, Stroke and Recovery Magalie Viallon1, Andrea Federspiel2, Stephen Altrichter1, Aphrodite Syrogiannopoulou1, Roman Sztajzel1, Maria-Isabel Vargas1, Jacqueline Delavelle1, Karl Olof Lövblad1 1Hopital Universitaire de Genève, GENEVA, Switzerland; 2University Hospital of Psychiatry, BERN, Switzerland

Improving diagnosis, prognosis and management patient with cerebral vascular diseases means determining degree of tissue injury, location of occlusion and ischemic lesions, presence or not of micro-hemorrhages, of collateral luxury perfusion or not, etc. We believe that advanced new technique like ASL and SWI can bring new determinant informations to hightligh the hemodynamic compromise and improve patient management, with ASL being an helpful technique to follow reliably recovery. We try to address on 30 patients how ASL and SWI added to a clinical stroke protocol could lead to improved diagnosis, prognosis and patient management.

Poster Sessions

328

1954. Which Physiological Parameters Determine Outcome in the Acute and the Subacute Phases of Acute Ischemic Stroke? Kristjana Yr Jonsdottir1, Leif Ostergaard1, Kim Mouridsen1 1Aarhus University Hospital, Aarhus, Denmark

Patients presenting with acute ischemic stroke within 3 hours of symptom onset are routinely treated with rt-PA. However, chronic tissue damage may not be avoided by acute recanalization alone. We use predictive algorithms to characterize the temporal evolution of infarct risk in acute stroke, and assess the extent to which perfusion and diffusion MRI parameters predict subsequent infarct. Perfusion parameters are primarily dominant for the risk of tissue damage in acute phases, while diffusion determines final outcome in sub-acute phases. We speculate that predictive algorithms may elucidate the diagnostic significance of imaging findings at various time intervals after stroke onset.

1955. Clinical Utility of Parametric Perfusion Estimates in Prediction of Final Outcome in Acute Stroke Kim Mouridsen1, Kristjana Yr Jonsdottir1, Sune Jespersen1, Leif Ostergaard1 1Aarhus University Hospital, Aarhus, Denmark

DSC-MRI parameters such as cerebral blood flow (CBF) and mean transit time (MTT) are important diagnostic maps, e.g. in acute stroke where they are used to identify ischemic regions. These parameters are commonly estimated using standard SVD (sSVD) or block-circulant SVD (oSVD). Recently, a parametric Bayesian approach based on a physiological model of the microvasculature has been suggested which additionally allows computation of oxygen extraction fraction (OEF). Here we use voxel-wise predictive algorithms to demonstrate that the parametric model leads to significantly improved prediction of final infarct size. Moreover, the highest performance is observed by inclusion of the OEF.

1956. DSC-MRI Errors Due to Bolus Delay and Dispersion in Sub Acute Stroke Patients: Implications for Extending the Therapeutic Time Window Lisa Willats1, Alan Connelly1, 2, Henry Ma, 23, Geoffrey Donnan2, 3, Fernando Calamante1, 2 1Brain Research Institute, Melbourne, Australia; 2University of Melbourne, Melbourne, Australia; 3National Stroke Research Institute, Melbourne, Australia

DSC-MRI perfusion measurements in stroke patients with cerebrovascular abnormalities are often erroneous because of bolus delay/dispersion. Treatment of ischaemic stroke patients using thrombolytic agents such as tissue-type plasminogen activator (tPA) is currently restricted to a logistically demanding time window of less than 3 hours from symptom onset. Extension of this time window in individual patients requires reliable perfusion information. We show that the presence of dispersion causes an overestimation of the perfusion abnormality using standard and delay insensitive deconvolution analyses in a group of sub acute patients, and present a methodology to minimise dispersion errors in the affected patients.

1957. Predicting Infarct Growth with Multi-Parametric Modeling in Acute Ischemic Stroke Michael S. Bristow1, Brett W. Poulin1, Jessica E. Simon1, Michael D. Hill1, Jayme C. Kosior2, 3, Shelagh B. Coutts1, 4, Richard Frayne, 13, J Ross Mitchell, 13, Andrew M. Demchuk1, 4 1University of Calgary, Calgary, Canada; 2Schulich School of Engineering, Calgary, Canada; 3Seaman Family MR Research Centre, Calgary, Canada; 4Hotchkiss Brain Institute, Calgary, Canada

The purpose of this study was to determine if different multi-parametric models optimally distinguish infarct growth from each of the physiologically distinct core infarct and region of benign oligemia in acute ischemic stroke. We used logistic regression analysis to build models using diffusion- and perfusion-weighted MR imaging parameters that differentiate among these regions in 13 acute ischemic stroke patients. Interaction among MR parameters was also tested. We found that indeed different parameters, and consequently different models, optimally distinguish infarct growth from core infarct as compared to those that optimally distinguish infarct growth from benign oligemia.

1958. Semi-Automated Topographical Scoring for MR Imaging of Ischemic Stroke Robert Karl Kosior1, 2, Nikolai Steffenhagen2, Jayme Cameron Kosior1, 2, Andrew M. Demchuk2, 3, Richard Frayne2, 3 1University of Calgary, Calgary, Canada; 2Foothills Med Ctr, Calgary Health Region, Calgary, Canada; 3Hotchkiss Brain Institute, University of Calgary, Calgary, Canada

The Alberta Stroke Program Early CT Score (ASPECTS) is a topographical stroke scoring system based on the regional occupancy of identifiable brain infarct lesions on CT images. Infarct can also be detected by MR diffusion-weighted imaging (DWI). ASPECTS may be extended to MR and such an approach may have advantages over CT. We assessed ASPECTS-based MR topographical scoring (auto-MR-TS) using a digital brain atlas for 30 ischemic stroke patients. There were small but significant differences between auto-MR-TS and ASPECTS. Auto-MR-TS is objective and reproducible and may provide greater accuracy through greater lesion sensitivity.

1959. Can Diffusion Tensor Imaging Detect the Degree of Neuronal Cell Membrane Damage in Stroke Patients? : A Patient Study Koji Sakai1, 2, Kei Yamada3, Susum Mori2, Tsunehiko Nishimura3 1Kyoto University, Kyoto, Japan; 2Johns Hopkins University, USA; 3Kyoto Prefectural University of Medicine, Japan

We attempted to further extend our hypothesis to real life brain infarctions involving the tightly packed white matter bundle. We performed retrospective measurements of diffusion tensor coefficients on patient with hyperacute/acute stage infarction involving posterior limb of internal capsule. From the results, we will consider the changes of diffusion tensor coefficients as the function and structure changing discriminants in hyperacute/acute brain infarction at different stage.

Poster Sessions

329

1960. Elevations of Diffusion Anisotropy Are Associated with Hyper-Acute Stroke: A Serial Imaging Study Yusuf A. Bhagat1, Muhammad S. Hussain1, Robert W. Stobbe1, Kenneth S. Butcher1, Derek J. Emery1, Ashfaq Shuaib1, Muzzafar M. Siddiqui1, Perkash Maheshwari1, Fawaz Al-Hussain1, Christian Beaulieu1 1University of Alberta, Edmonton, Canada

DTI studies of human ischemic stroke ≤24 hours of symptom onset have reported variable findings of changes in diffusion anisotropy. To address these heterogeneous results, we characterized longitudinal changes of fractional anisotropy (FA) by analyzing discrete ischemic deep and subcortical white matter, and deep and cortical gray matter regions during the hyperacute (2.5-7h) and acute (21.5-29h) phases of stroke onset in 13 patients. Overall, 9/13 patients scanned ≤7h showed elevated FA in at least one of the four tissues, and within the same cohort, 11/13 patients showed reduced FA in one of the four tissues 21.5-29h after stroke.

1961. Comparing Mean and Directional Diffusivity in Human Ischemic Stroke Chin-I Chen1, 2, Tammie L.S. Benzinger2, Peng Sun2, Tzy-Haw Wu, 23, Agus Priatna4, Chung-Yi Hsu5, Sheng-Kwei Song2 1Taipei Medical University - Wanfang Municipal Hospital, Taipei, Taiwan; 2Washington University, School of Medicine, St Louis, Missouri, USA; 3National Taiwan University Hospital, Taipei, Taiwan; 4Siemens Medical Solutions, USA, Inc, USA; 5Graduate Institute of Neuroscience, Taipei Medical University, Taipei, Taiwan

We present a study which compared DWI and DTI study in ischemic stroke with four different parameters: apparent diffusion coefficient (ADC), scaled relative anisotropy (sRA), axial diffusivity (AD) and the radial diffusivity (RD). We found the ADC and AD are significantly decreased in acute/subacute cases. RA and RD show the same trend but not statistically significant. In conclusion, axial diffusivity is comparable to ADC. DTI could potentially provide a quantitative biomarker to evaluate the ischemic stroke and predict outcome.

1962. Neural Predictors of Immediate and Delayed Intense Naming Training Success in Chronic Aphasia Harald Kugel1, Ricarda Menke1, Michael Deppe1, Annette Baumgaertner2, Hagen Schiffbauer1, Marion Thomas1, Kira Kramer1, Hubertus Lohmann1, Walter Heindel1, Stefan Knecht1, Caterina Breitenstein1 1University of Muenster, Muenster, Germany; 2Univerity Medical Center Hamburg-Eppendorf, Hamburg, Germany

Intense training facilitates the reacquisition of language in the chronic stage after stroke. We investigated with functional MRI, which brain regions are involved in immediate versus long-term success of intense naming training in patients with single left hemisphere strokes involving both Broca's and Wernicke's areas. All patients significantly improved after training. Short-term training success was predicted by increased activity in hippocampi, (pre)motor and attention areas, and right occipital lobe. Long-term training success, however, was predicted by increased activity in the left superior temporal lobe perilesionally to Wernicke's area and in the right-sided Wernicke's homologue.

1963. Cerebrovascular Reserve Impairment is Associated with Recurrent Events in Patients with Carotid Artery Occlusion Stephen Goode1, Sunil Munshi2, Shane MacSweeney2, Dorothee Auer2 1Nottingham University Hospitals (NUH), Nottingham, UK; 2NUH, UK

Cerebrovascular reserve (CVR) measurements have been shown to be useful in predicting haemodynamic impairment and risk of future ischaemic events in patients with carotid artery disease. The aim of this study was to investigate the CVR of patients with carotid artery occlusion in relation to the presence of recurrent symptoms using hypercapnia fMRI. 13 patients with symptomatic carotid artery occlusion were scanned(1.5T). The degree of side-to-side asymmetry in the brain was calculated using the Asymmetry Index for all patients. In patients with recurrent symptomatic episodes we found a significantly increased asymmetry with ~18% ipsilateral reduced CVR.

1964. Q-Ball MR Imaging of Longitudinal Brain Rewiring During Functional Recovery After Ischemic Stroke Cristina Granziera1, Thomas Benner2, Dave Tuch2, Aneesh Singhal3, Walter Koroshetz3, Gunnar Krueger, Gregory Alma Sorensen2 1CHUV, Lausanne, Switzerland; 2Martinos Center-MGH-Harvard medical school, Charlestown, Massachusetts, USA; 3MGH, Boston, Massachusetts, USA

Investigating connectivity changes underlying post-stroke recovery is a challenging research’s field, with a potential future impact in treatment options and rehabilitation. We applied Q-ball MRI to monitor white matter plasticity in patients recovering from small MCA strokes. Our results showed a decrease in fiber trajectories at 1 month after stroke followed by a relative increase at 6 months in functional tracts involved in patients’ symptoms. This phenomenon could be due to masking/unmasking of the dominant ODF (edema, cellular/connectivity necrosis or damage) or to initial axonal degeneration followed by regenerative phenomena. Q-ball MRI appears a valuable method to establish new therapeutic targets in stroke rehabilitation. Larger cohort studies are needed to confirm these preliminary findings.

Clinical Imaging with DTI & fMRI Hall D Monday 14:00-16:00

1965. Diffusion Tensor Peripheral Nerve Tractography ~ Histological Changes and Diffusion Anisotropy ~ Takehiko Takagi1, 2, Masaya Nakamura1, Masayuki Yamada2, Keigo Hikishima3, Suketaka Momoshima1, Kanehiro Fujiyoshi1, Hirotaka James Okano1, Yoshiaki Toyama1, Hideyuki Okano1 1Keio University School of Medicine, Shinjuku-ku, Japan; 2Fujita Health University School of Health Sciences, Toyoake, Japan; 3Keio University Center of Integrated Medical Research, Shinjuku-ku, Japan

We tried to determine whether noninvasive diffusion tensor tractography (DTT) could be used to track the peripheral nerve and whether recovery from contusion would show up as in ability to track fibers distal to the lesion site, correlating with histological and functional recovery. Diffusion tensor MRI data and fiber tracking were analyzed for peripheral nerve injury. We also measured fractional anisotropy (FA) values, histological and functional parameters. FA values reflected histological and functional changes, demonstrating the possible contribution of DTT to the evaluation of the some clinical events for peripheral nerve degeneration and regeneration.

Poster Sessions

330

1966. Functional MRI Detection of Acute and Chronic Brain Plasticity Following Median and Ulnar Nerve Transection Using Direct Nerve Stimulation at 9.4T Rupeng Li1, Seth R. Jones1, Christopher Pawela1, Daniel Lee Shefchik1, Ji-Geng Yan1, Safwan S. Jaradeh1, Hani S. Matloub1, James S. Hyde1 1Medical College of Wisconsin, Milwaukee, USA

This study has four novel aspects. First, it showed, pure motor nerve activation in the rat central nervous system can be demonstrated using fMRI. Second, it proved that the motor nerve is less sensitive to injury than the sensory nerve. Third, it showed that inter-hemispheric brain plasticity occurs in the motor and sensory areas even if more than one nerve of the brachial plexus is intact. Finally, the thalamus and caudate putamen were activated in different ways in acute and chronic brain plasticity, which suggests that they may also play an important role in brain reorganization.

1967. Cerebral White Matter Changes in Chronic Kidney Disease Patients Using DTI Jiachen Zhuo1, Jiazheng Wang1, 2, Stephen Seliger1, David Lefkowitz1, Joshua Betz, 12, Shari Waldstein2, Leslie Katzel, 3, Steven Roys1, Rao Gullapalli1 1University of Maryland School of Medicine, Baltimore, Maryland, USA; 2University of Maryland Baltimore County, Baltimore, Maryland, USA; 3Baltimore Veterans Affairs Medical Center, Baltimore, Maryland, USA

Large prevalence of cerebral atherosclerosis and brain infarcts has been described in chronic kidney disease(CKD) patients. On 27 CKD patients, we used whole-brain/regional analysis and voxel-based-morphometry of DTI data to examine their brain white-matter(WM) changes. Both ADC and FA values were altered globally and regionally in CKD patients, reflecting disruption of WM microstructure. Among patients, higher GFR correlated with lower ADC and higher FA within the corpus-callosum. Regional microstructural changes were also more pronounced among diabetic compared to non-diabetic CKD patients. Our results indicate that DTI is able to differentiate morphological changes corresponding to functional changes in CKD patients.

1968. Validation of Diffusion Tensor Imaging Tractography of Language Tracts with Intraoperative Subcortical Stimulations Delphine Leclercq1, Hugues Duffau, Laurent Capelle, Christine Delmaire, Peggy Gatignol, Mathieu Ducros, Stephane Lehericy2 1Hopital Pitie-Salpetriere, Paris, France; 2Hopital Pitie Salpetriere, Paris, France

In this study, we used intraoperative subcortical electrical stimulations was to validate diffusion tensor imaging (DTI) tractography of language fiber tracts. Positive stimulation mapping was concordant with DTI fiber bundles in 81% of the stimulations. Stimulations of the different fasciculi induced variable language disorders that were specific of each fiber tract.

1969. Optic Radiation Impairment in Friedreich Ataxia: A Diffusion-Weighted Imaging and Neurophysiological Study David Neil Manners1, Giovanni Rizzo1, Filippo Fortuna1, Valerio Carelli1, Maria Lucia Valentino1, Emil Malucelli1, Caterina Tonon1, Rocco Liguori1, Bruno Barbiroli1, Raffaele Lodi1 1Università di Bologna, Bologna, Italy

Optic impairment is common in mitochondrial disorders. Its occurrence in Friedreich Ataxia (FRDA) has been recognized for a long time, but poorly characterized. Diffusion weighted imaging (DWI), which can disclose increased water apparent diffusion coefficient (ADC) in brain areas where axonal loss occurs, and visual evoked potentials (VEPs) were used to look for evidence of optic radiation involvement in FRDA patients. We provide evidence that microstructural damage of the optic radiations in FRDA patients contributes to clinical and neurophysiological visual involvement in this disease.

1970. Greater Attentional Modulation in HIV Patients: A One-Year Follow-Up Study Linda Chang1, Renat Yakupov1, Grace Crocket1, Mary Ricardo-Dukelow1, Helenna Nakama1, Michael Watters1, Thomas Ernst1 1John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, USA

HIV-infection can lead to decreased attention, which may be further exacerbated with aging. Functional MRI was performed in 46 HIV-subjects and 32 seronegative-controls during three visual attention tasks at baseline and one-year. Over one-year, these clinically stable HIV-patients showed increased BOLD signals in the load regions of the attention network for all tasks, while controls showed decreased activation in the attention network for one task. These findings suggest that HIV patients required increased usage of reserve regions to maintain performance with aging after only one year. Further longitudinal follow-up will determine whether this reserve capacity will exhaust with further aging.

1971. Diffusion-Weighted Imaging and Magnetization Transfer Imaging of Tardive and Edentulous Orodyskinesia Yvan Boulanger1, Abdesslem Khiat1, Yevgeniy Kuznetsov1, Pierre J. Blanchet2 1CHUM, Montreal, Canada; 2Université de Montréal, Montreal, Canada

The possibility of using diffusion-weighted imaging (DWI) and magnetization transfer imaging (MTI) parameters as markers of dyskinesia was investigated by comparing data for four groups of subjects: drug-treated patients with tardive dyskinesia (TD), edentulous orodyskinesia patients (EOD), drug-treated patients without TD and control subjects. Apparent diffusion coefficients (ADC) were increased in the basal ganglia in drug-treated patients with TD relative to those without TD and to control subjects as well as in EOD patients relative to control subjects. Magnetization transfer ratios (MTR) were also increased in EOD patients relative to control subjects but ADC values offered the best discrimination potential.

1972. Normalization of FMRI Activation Patterns in HIV Positive Individuals with Cognitive Impairment After Treatment with Lithium Giovanni Schifitto1, Michelle D. Gaugh1, Madalina Tivarus1, Tong Zhu1, Kim Cruttenden1, David Gill2, Jianhui Zhong, 13, Harris A. Gelbard1 1University of Rochester, Rochester, New York, USA; 2Pennsylvania State University, Hershey, Pennsylvania, USA; 3University of Rochester, Rochester, New York, USA

HIV positive patients with cognitive impairment were enrolled in a ten-week clinical trial of lithium 300mg BID, and administered an FMRI working memory task at baseline and week 10. A group of HIV positive patients without impaired cognitive functioning were administered the same task at a single time point. Results indicate that activation patterns in post-treatment lithium patients more closely resemble patterns of HIV patients without impairment than activation patterns in lithium patients before treatment, and suggest that lithium may normalize brain activation during a working memory task in HIV patients with cognitive impairment.

Poster Sessions

331

1973. The Brain's FMRI Response to Heat-Pain Stimulation in Diabetic Neuropathy Iain D. Wilkinson1, Rajiv A. Gandhi2, Michael D. Hunter1, Dinesh Selvarajah2, Celia J. Emery2, Paul D. Griffiths1, Solomon Tesfaye2 1University of Sheffield, Sheffield, UK; 2Royal Hallamshire Hospital, Sheffield, UK

Abnormal pain perception is common in Diabetic Neuropathy (DN). This work investigates the brain’s response to pain stimulation in patients with Diabetes Mellitus using BOLD fMRI. Twenty-three males took part: 5 without diabetes, 6 with diabetes without DN; 6 with diabetes with painful DN and 6 with diabetes with painless DN. Heat-pain stimulation was provided by a peltier-type device during BOLD-fMRI. Brain response was compared using SPM. Analysis indicates differences in the brain’s haemodynamic response to heat-pain between subject groups at different stages of DN with a negative correlation between composite neuropathy score and BOLD response within the thalamus.

1974. Differentiating Pain-Intensity from Stimulus Encoding in Brain Activation in Neuropathic Pain lino Becerra1, 2, Gautam Pendse1, david Borsook1, 2 1McLean Hospital, Belmont, Massachusetts, USA; 2Massachusetts General Hospital, Boston, Massachusetts, USA

We studied neuropathic pain patients with pain to one side of the face. We sought to determine brain structures that encoded pain intensity regardless of stimulated side; brain substrates that encoded sensation regardless of the perception of the stimulus (painful or not); and brain structures whose activation significantly differed between the affected and unaffected side but that do not encode pain intensity. Thermal (heat and cold) and mechanical (brush) stimuli were used to evoke pain.

1975. fMRI in Patients with Lumbar Radiculopathy Harish Sharma1, Raj Gupta2, Bill Olivero3 1University of Illinois at Urbana-Champaign, Urbana, Illinois, USA; 2UIC college of Medicine at Urbana-Champaign, USA; 3Carle Hospital, USA

fMRI is used as a tool to study how brain processes pain. Most of the studies done are fMRI with artificially induced pain on normal subjects. In the current study we have tried to use fMRI in understanding where and how chronic pain is processed in the brain. Our analysis showed activations in the pain centers of the brain when the patient experienced pain while no activation was observed when the patient experienced no pain.

1976. Visual Cortex Reorganization Among Early and Late Blind for Tactile Object Recognition Anand Mohan Sinha1, Senthil S. Kumaran1, Rohit Saxena1, Uma Sarma1 1All India Institute of Medical Sciences, New Delhi, India

Using BOLD fMRI technique, we investigated the differences between early and late blind subjects on tactile object recognition task. We observed early blind predominantly recruiting temporal-frontal whereas late blind subjects had significant parietal-frontal activation. This contrasting activation pattern suggests adaptive changes in brain with input of visual stimuli.

MRA & Flow: Physiology & Diseases Hall D Tuesday 13:30-15:30

1977. High-Speed MR Imaging of Intervascular Physiolgy Theodore J. Huppert1, Broc A. Burke, Solomon G. Diamond 1University of Pttsburgh, Pittsburgh, Pennsylvania, USA

Using high-speed (9.4Hz) T1-weighted functional MRI, we examine the physiological oscillations within the cerebral vasculature. We examine the temporal dynamics of signals from the major cerebral arteries and veins and explore the different characteristics of these signals and their relationships to systemic physiology.

1978. Improving Radial Sliding Window Cotrast-Enhanced Intracranial MRA Using HYPR Hyun Jeong1, Christpher S. Eddleman1, Christopher Getch1, Matthew Walker1, Ty A. Cashen1, Timothy John Carroll1 1Northwestern University, Chicago, Illinois, USA

Intracranial contrast-enhanced angiography using radial sliding window reconstruction has been improved using HYPR processing. Using a sliding composite for the HYPR, significant increase in SNR was observed without significant changes in temporal profiles. Patients with angiographically confirmed AVMs were imaged.

1979. Hybrid STAR MR Angiography of the Intracranial Circulation Robert R. Edelman1, 2, Ioannis Koktzoglou1, 2 1Evanston Northwestern Healthcare, Evanston, Illinois, USA; 2Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA

We propose a new approach to imaging of the intracranial circulation called hybrid STAR. Volunteers were imaged on a 1.5T Siemens Avanto system. Maximum lengths (in mm) for the ACA, MCA, PCA, and basilar artery (hybrid STAR vs. 3D TOF) were 113 ± 10 vs. 84 ± 17 (p < 0.01), 164 ± 10 vs. 126 ± 27 (p < 0.01), and 119 ± 11 vs. 89 ± 19 (p < 0.05). Hybrid STAR depicted significantly more branching vessels. Our preliminary results suggest the hybrid STAR technique provides much improved depiction of the intracranial circulation than has previously been feasible.

1980. Evidence of Vascular Steal in the Cerebral Circulation Jeff A. Stainsby1, Julien Poublanc2, Adrian Crawley2, Daniel M. Mandell2, Jay S. Han3, Joe A. Fisher3, David J. Mikulis2 1GE Healthcare, Toronto, Canada; 2The Toronto Western Hospital, Toronto, Canada; 3Toronto General Hospital, Toronto, Canada

Measurements of Cerebral Vascular Reactivity using BOLD MRI provide can probe the autoregulatory capacity of the brain. Diseased tissue may often present with a negative reactivity (reduction in BOLD signal) following inhalation of carbon dioxide. This paper presents data comparing the CVR response, the timing of the response and the timing of blood flow arrival as measured by dynamic susceptibility contrast MR that supports the steal hypothesis used to explain these regions of negative reactivity.

Poster Sessions

332

1981. MR Susceptibility Weighted Imaging with Multi-Echo Acquisition Yiping P. Du1, Zhaoyang Jin2, 3 1University of Colorado Denver School of Medicine, Denver, Colorado , USA; 2Hangzhou Dianzi University, Hangzhou, People's Republic of China; 3Zhejiang University, Hangzhou, People's Republic of China

A multi-echo 3D gradient-recalled echo pulse sequence was developed to improve the visibility of veins in susceptibility weighted imaging (SWI). Three echoes with echo times of 19.7ms, 23.4ms, and 37.6ms were acquired in a TR of 47ms. The veins were better depicted in short TE dataset in regions with severe field inghomogeneity due to reduced image artifacts. The veins in other regions have higher visibility in long TE dataset.

1982. High Resolution MR Susceptibility Weighted Imaging with Partial 3D K-Space Acquisition Zhaoyang Jin1, 2, Ling Xia2, Yiping P. Du3 1Hangzhou Dianzi University, Hangzhou, People's Republic of China; 2Zhejiang University, Hangzhou, People's Republic of China; 3University of Colorado Denver School of Medicine, Denver, USA

Partial 3D k-space acquisition with partial echo and unsampled ky and kz views were used to reduce the scan time in susceptibility weighted imaging (SWI). Three-dimensional projection onto convex sets (POCS) algorithm was used for image reconstruction. Views at the corners of (ky,kz) domain were unsampled to further reduce scan time. A 3D Fermi filter was used to increase the signal-to-noise ratio and reduce angular dependence of spatial resolution. The effects of a 44% partial k-space acquisition and Fermi filter on the visibility of venous vasculature were demonstrated.

1983. Automatic Reconstruction of Different Types of Magnetic Resonance Angiograms: Comparison, Evaluation and Reliability Michael Sibila1, 2, André Manuel Gaudnek1, 2, Monika Carola Lehmpfuhl3, Klaus Helmuth Obermayer1, 2, Andreas Hess, 24 1University of Technology, Berlin, Germany; 2Bernstein Centre for Computational Neuroscience, Berlin, Germany; 3Ludwig Maximilians University, Munich, Germany; 4Friedrich Alexander University Erlangen/Nuremburg, Erlangen, Germany

Since angiograms show blood vessels as spatially closely confined features, they can be used to register MR images of other types (e.g. fMRI) acquired in the same imaging session. This is only possible if MRA delivers reliable, reproducible images and does not show major random distortions. Therefore, we examine the reliability of MRA over subsequent scanning sessions and different imaging methods(2DTOF, 3DTOF,PC-MRA). Using an appropriate distance measure on our automatically generated geometric vasculature models, we examine the variance between different specimens in order to value the possibility of inter-specimen registration. We further use the rheological information contained in PC-MRA to investigate the reconstructed geometric models with respect to their function by means of fluid dynamics.

1984. Combination of Parallel Imaging and a Cut-Corner Acquisition for Neurovascular 4D-Flow Thomas A. Hope1, Michael D. Hope, Roland Bammer, Marcus T. Alley 1Kaiser San Francisco, San Francisco, California , USA

Time-resolved three-dimensional phase-contrast MRI (4D-flow) is a tool for imaging blood flow velocity profiles, but is limited in its clinical applications by its long scan time. In this study, we analyze the effect of the combination of GRAPPA with an acquisition that removes the corners of k-space in order to further limit scan time. We also analyzed the effect on both mean velocity across the vessel lumen as well as the difference between individual velocity vectors, as individual vectors may effect calculations of wall shear stress and other variables that depend on the local velocity field. We show that the combination of a cut-corner acquisition to parallel imaging results in minimally decreased image quality when combined with GRAPPA while decreasing scan time by 20%.

1985. Curve-Fitting Aided Pressure Gradient Assessment in Aqueduct of Sylvius Ming-Yen Chen1, Hsiao-Wen Chung1, Teng-Yi Huang2, Cheng-Yu Chen3 1National Taiwan University, Taipei, Taiwan; 2National Taiwan University of Science and Technology, Taipei, Taiwan; 3Tri-Service General Hospital and National Defense Medical Center, Taipei, Taiwan

Intracranial pressure (ICP) measurement was significant for diagnosis and treatment in hydrocephalus diseases. Noninvasive ICP MR estimation was proposed by Noam Alperin [1]. However, spatial and temporal limitations in cerebrospinal fluid (CSF) flow study of aqueduct of Sylvius, which were still bothered researchers¡¦ assessment. Since its small structure is deeply located in a brain, according to our past studies [2], the total pixels in aqueduct imaging were merely 9~25 in normal volunteers. Therefore, time-varying pressure gradient individually derived from each correspondingly spatial-averaged CSF velocity data, which might far identify with profile of velocities in these aqueduct-segmented pixels. This project aimed at evaluating through-plane flowing time-varying functions set by 2D curve-fitting method. By using a simplified Navier Stokes equation [1], we could depict deliberatively in ICP measurement. Here, we also compared different 2D curve-fitting methods, e.g. 4-order polynomial, parabolic and Gaussian fitting, when they applied to cine phase contrast (PC) MR images.

1986. Compare Image Segmentation Methods for Evaluating Aqueductal CSF Hemodynamic Ming-Yen Chen1, 2, Hsiao-Wen Chung1, 3, Teng-Yi Huang4, Cheng-Yu Chen3 1National Taiwan University, Taipei, Taiwan; 2Yuanpei University of Science and Technology, Hsin-Tzu, Taiwan; 3Tri-Service General Hospital and National Defense Medical Center, Taipei, Taiwan; 4National Taiwan University of Science and Technology, Taipei, Taiwan

According to our past studies, even sacrificed outside of aqueduct region with partially spatial overlapped, the total pixels in aqueduct imaging were merely 9~25 in normal volunteers. Therefore, post-processing in image segmentation played an important role in calculating aqueductal area, stroke volume and related flow parameters. To avoid errors from inter-observer and intra-observer in region of interest (ROI) selection, we adopted automated image segmentation, including adaptive threshold in magnitude image, pulsatility based segmentation (PUBS) and independent component analysis (ICA). For accuracy and precision, both phantom and normal human study by using 2D cine magnetic resonance phase contrast imaging were compared.

Poster Sessions

333

1987. Venous Outflow of Label in ASL Perfusion MRI of Healthy Children and Children with Sickle Cell Disease Wen-Chau Wu1, Hengyi Rao1, Mikolaj A. Pawlak1, Kim M. Cecil2, John VanMeter3, Thomas A. Zeffiro4, John A. Detre1, Elias R. Melhem1, Jiongjiong Wang1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA; 2Cincinnati Children's Hospital, Cincinnati, Ohio, USA; 3Georgetown University Medical Center, Washington DC, USA; 4Massachusetts General Hospital, Boston, Massachusetts, USA

In perfusion studies of human brain using arterial spin labeling methods, it is generally assumed that all labeled water will exchange into brain tissue or relax before reaching the venous end. However, venous outflow of the label can present with elevated flow and prolonged blood T1 such as in a child’s brain. In the present study, venous outflow were detected as hyperintensities in the saggital sinus and further quantified as a function of the average flow in gray matter in healthy children and children diagnosed with sickle cell disease. Our data demonstrated significant venous outflow effects in the pediatric population.

1988. Identification of MR Biomarkers to Predict Outcome in Patients Undergoing Endoscopic Third Ventriculostomy Alan Jackson1, Deborah Sinclair2, Stavros Stivaros3 1University of Manchester, Withington, UK; 2Salford Royal Hospitals NHS Trust, Salford, UK; 3University of Manchester, Manchester, UK

We have examined the relationship between premorbid measurements of CSF and blood flow measurements to predict objective changes in brain volume and ventriculostomy flow in a group of patients undergoing third ventriculostomy for communicating hydrocephalus

1989. Arterial Spin Labeling MRI Measurements of Timing Parameters in Relation to Collateral Flow Patterns in Patients with Carotid Artery Occlusion Reinoud Pieter Harmen Bokkers1, Peter Jan van Laar1, Kim C C van de Ven1, L J. Kappelle1, C J M Klijn1, Jeroen Hendrikse1 1University Medical Center Utrecht, Utrecht, Netherlands

Arterial spin labeling (ASL) at multiple delay times can be exploited in perfusion MRI imaging to visualize and quantify the temporal dynamics of blood inflow. This is the first study to investigate the consequences of internal carotid artery (ICA) occlusion and collateral blood flow patterns on regional timing parameters. Assessment of timing parameters in patients with ICA occlusion (n=17) demonstrated regional heterogeneity. With presence of leptomeningeal collaterals, impaired cerebral hemodynamics was found in the frontal region, indicating that ASL can be used to quantify the delay of arterial blood associated with collateral perfusion and the extent of such collateral perfusion.

1990. Arterial Spin Labeling Perfusion MRI at Multiple Delay Times in Patients with an Internal Carotid Artery Occlusion: A Correlative Study with 15O Positron Emission Tomography Reinoud Pieter Harmen Bokkers1, Jeroen Hendrikse1, J P. Pluim1, J M. Bremmer1, C J M Klijn1 1University Medical Center Utrecht, Utrecht, Netherlands

Arterial spin labeling (ASL) perfusion MRI at multiple delay times has previously been introduced as an ASL method to compensate for the blood transit delays in patients with an internal carotid artery (ICA) occlusion. The aim of this work was to compare the use of ASL at multiple TIs and Oxygen-15 PET in patients with a symptomatic ICA occlusion. Assessment of CBF with both PET with ASL demonstrated a good correlation between CBF gray (r=0.54, p<0.01) and white-matter (r=0.53, p<0.01), indicating that ASL at multiple TIs can be used in clinical practice as a non-invasive technique to assess brain perfusion.

1991. Mid-Sagittal Saturated MRA for Assessment of Blood Flow from STA-MCA Bypass Toshiaki Akashi1, 2, Toshiaki Taoka1, Hiroyuki Nakagawa1, Toshiteru Miyasaka1, Masahiko Sakamoto2, Satoru Kitano1, Satoru Iwasaki3, Kimihiko Kichikawa1 1Nara Medical University, Kashihara, Japan; 2Nara Prefectural Nara Hospital, Nara, Japan; 3Higashiosaka City General Hospital, Higashiosaka, Japan

Conventional MRA and contrast angiography have been selected as modalities to assess the bypass flow following STA-MCA bypass. However, conventional MRA can not differentiate whether the blood flow come retrograde from the bypass or antegrade. Whereas external carotid angiography (ECAG) can demonstrate the bypass flow, it is invasive and may not show natural flow because of pressure injection of contrast. We demonstrated usefulness of time of flight MRA with saturation band in the mid-sagittal area to suppress signal from internal carotid arteries (gMid-sagittal saturated MRAh) for visualization of natural bypass flow from STA-MCA, and agreement with the ECAG.

1992. Improvement in Patients Cerebrovascular Reserve Following Carotid Endarterectomy Stephen Goode1, 2, Shane MacSweeney3, Dorothee Auer3 1Queens Medical Centre, Nottingham, UK; 2NUH, Nottingham, UK; 3NUH, UK

In patients with symptomatic carotid artery disease(CAD) the predominant mechanism causing ischaemic injury is considered to be thromboembolic, however cerebral haemodynamics can also be compromised. Currently data concerning haemodynamic status before and after carotid endarterectomy(CEA) is insufficient. The aim of this study was to assess the haemodynamic effects of CEA on CVR in patients with CAD using hypercapnia fMRI. 12 patients with symptomatic CAD were scanned. Following CEA there is a significant improvement in the ipsilateral CVR but no improvement in the contralateral territory. Assessment of the AI in these patients revealed that this asymmetry is actually reversed following intervention.

1993. A Contrast Dose Reduction Study for 3D High-Spatial Resolution Contrast-Enhanced Cerebral Magnetic Resonance Venography at 3.0 Tesla Anderanik Tomasian1, Noriko Salamon, Mayil Krishnam, J. Pablo Villablanca, J. Paul Finn 1UCLA, Los Angeles, USA

The purpose of our study was to prospectively establish the non-inferiority of diminished dose regimens compared to higher dose regimens as reflected in the diagnostic image quality of high-spatial-resolution three-dimensional MR angiography of the supra-aortic arteries at 3.0 Tesla.High-spatial-resolution cerebral CE-MRV performed comparably well with the two contrast dose regimens for evaluation of large intra-cranial venous structures at 3.0T

Poster Sessions

334

1994. 3D TOF MR Angiography at 3T vs. Catheter Angiography: A Quantitative Comparison Sanjoy Nagaraja1, Kuan J. Lee1, David Capener1, Stuart Coley, Matthew Kaduthodil, Lee Walton, Jim M. Wild1, Andras Kemeny, Iain D. Wilkinson1, Paul D. Griffiths1 1University of Sheffield, Sheffield, UK

Arteriovenous malformations in the brain are complex vascular lesions that are a major cause of haemorrhagic stroke. We used MRA at 3T to measure nidal maximum linear dimensions, nidal volumes and the number of venous drainers, and compared the results with measurements made with the gold standard, catheter angiography.

1995. In-Vivo Plaque Imaging of the Carotid Arteries at 7 Tesla: First Results Oliver Kraff1, 2, Stefan Maderwald1, 2, Steffen Hahn1, 2, Jens M. Theysohn1, 2, Mark E. Ladd1, 2, Joerg Barkhausen1, 2, Elke R. Gizewski1, 2, Harald H. Quick1, 2 1Erwin L. Hahn Institute for MRI, Essen, Germany; 2University Hospital Essen, Essen, Germany

Recently, imaging of the carotid arteries at 3T has demonstrated the advantages of high-field MRI in plaque depiction. To further push the limits of high-field carotid MRI, our study aimed to optimize different 2D and 3D GRE and TSE sequences for plaque imaging at 7T using a transmit/receive single loop coil. The sequences were first optimized in five healthy volunteers and subsequently tested in one patient. Plaque and degeneration of the vessel wall were clearly visible in the 7T images. SAR restrictions, difficulties with the ECG trigger, and high-field related image artifacts were identified as challenges of 7T carotid MRI.

1996. 3D High Resolution Susceptibility Weighted Imaging (SWI) Venography at 3T and 7T Yulin Ge1, Samuel Barnes, Samantha Heller1, Yingbiao Xu, Qun Chen1, E Mark Haacke, Robert I. Grossman1 1New York University School of Medicine, New York City, New York, USA

This work describes a markedly improved susceptibility weighted imaging (SWI) based venography that is acquired at 7T vs 3T. Preliminary results indicating the promise of using ultra-high field SWI to generate a high resolution and high quality venography by virtue of greatly increased signal-to-noise ratio (SNR) and susceptibility contrast.

ENT: Tumors, Anatomy & Functional Hall D Wednesday 13:30-15:30

1997. Squamous Cell Carcinoma of the Head and Neck: Can Diffusion Weighted Imaging (Dwi) Pre-Treatment and During Early Treatment with Chemoradiation Predict Therapeutic Response? Ann D. King1, Hua Zhou1, 2, Brian K H Yu1, David K W Yeung1, Frankie Mo1, Gary M K Tse3, Alex C. Vlantis1, Anil T. Ahuja1 1The Chinese University of Hong Kong, Shatin, Hong Kong; 2First Affiliated Hospital of Zhejiang University, Hangzhou, People's Republic of China; 3Prince of Wales Hospital, Shatin, Hong Kong

Diffusion-weighted imaging (DWI) is a MR technique that has been shown to be useful in the characterization of lesions. We investigated the usefulness of this technique in predicting treatment response in 31 patients with squamous cell carcinoma (SCC). ADC values from DWI of SCC decrease early in the course of treatment but the pre treatment ADC value and early change in ADC values does not seem to be able to predict tumor response.

1998. Squamous Cell Carcinoma of the Head and Neck: Can 1H MRS Pre-Treatment and During Early Treatment with Chemoradiation Predict Therapeutic Response? Ann D. King1, David K. Yeung1, Hua Zhou1, 2, Brian K H Yu1, Frankie Mo1, Gary M K Tse3, Alex C. Vlantis1, Anil T. Ahuja1 1The Chinese University of Hong Kong, Shatin, Hong Kong; 2First Affiliated Hospital of Zhejiang University, Hangzhou, People's Republic of China; 3Prince of Wales Hospital, Shatin, Hong Kong

In vivo 1H MR spectroscopy has been shown to be useful in the characterization of tumors, including those in the head and neck. Whether this technique may be useful to predict treatment response following chemoradiation treatment is not known. We employed this technique to examine 39 patients with squamous cell carcinoma (SCC) and to compare spectroscopy results with tumor response assessed at 6 weeks after treatment. Our results showed that this technique has limited use to predict treatment response in patients with SCC.

1999. The Evaluation of Radiation-Induced Changes in Water Content of the Parotid Gland Using MRI Antonetta Christina Houweling1, C A.T. van den Berg1, T Dijkema1, J M. Roesink1, C H. J. Terhaard1, C. P. J. Raaijmakers1 1University Medical Center Utrecht, Utrecht, Netherlands

The radiation-induced changes in water content of the parotid glands of five healthy subjects and three radiotherapy patients was evaluated with MR sialography and a multi-point Dixon technique. With MR sialography, the major ductal system of the parotid gland was visualized nicely. The water and fat content were successfully visualized using the multi-point Dixon technique. Radiation-induced changes in water content and the ductal system were not observed. However, the fat content appeared to change after radiotherapy.

2000. High Resolution MRI of the Parotid Gland and Duct at 7 Tesla Oliver Kraff1, 2, Jens M. Theysohn1, 2, Stefan Maderwald1, 2, Stefan Kruszona1, Mark E. Ladd1, 2, Elke R. Gizewski1, 2, Susanne C. Ladd1, 2 1Erwin L. Hahn Institute for MRI, Essen, Germany; 2University Hospital Essen, Essen, Germany

Most examinations of gland diseases are still performed with X-ray sialography. MR imaging at ultra high fields (7T) offers an increase in SNR and hence spatial resolution as well as new image contrasts which might be able to replace conventional sialography in the future. Our study aimed to optimize different PD and T2 weighted GRE and TSE sequences at 7T for high resolution MRI of the parotid gland and duct. The final imaging protocol at 7T provides a non-invasive examination within 20 minutes as well as excellent image contrast and resolution of the parotid duct and branches.

Poster Sessions

335

2001. Motion Corrected 3D High Resolution Larynx Imaging with a Two-Coil Array Joëlle Karine Barral1, Edward J. Damrose1, Dwight George Nishimura1 1Stanford University, Stanford, California , USA

Laryngeal cancer is usually treated with radiotherapy and chemotherapy to preserve speech and swallowing abilities. However, if the cartilage has been invaded, this treatment is ineffective and partial or total laryngectomy is required. The latter has a dramatic impact on the quality of life of the patient. If cartilage invasion is detected early, partial laryngectomy, with preservation of speech and swallowing, can be performed in lieu of total laryngectomy. A 3D trajectory is investigated to get coverage of the larynx at high resolution in less than 5 minutes with motion correction, and a two-coil array is proposed, which better fits the larynx geometry.

2002. Real-Time MRI of Swallowing in Upright Position Juan Manuel Santos1, Kim Butts Pauly1, Gerald R. Popelka1, John M. Pauly1 1Stanford University, Stanford, USA

Swallowing disorders are difficult to study because they have multiple etiologies and involve the careful coordination of many different oral structures. These oral structures are not readily visible in their natural state, nor are their mechanics completely understood We have adapted the RTHawk real-time system to the SP 0.5 T GE interventional MRI scanner allowing a person to be scanned in an upright position. Swallowing function can then be studied in a natural position with continuous real-time imaging.

2003. Application of Compressed Sensing to 3D Imaging of the Vocal Tract for Speech MRI Yoon-Chul Kim1, Jon-Fredrik Nielsen1, Shrikanth Narayanan1, Dani Byrd2, Krishna S. Nayak1 1Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California , USA; 2Department of Linguistics, University of Southern California, Los Angeles, California , USA

Three-dimensional (3D) MRI of the vocal tract during speech production has the potential to provide full anatomical information of the vocal tract shaping, but it requires prohibitively long scan time. In order to reduce scan time and achieve reconstructed image quality comparable to the image from fully sampled data, we apply the principle of compressed sensing MRI to 3D imaging of the vocal tract. Sustained unvoiced English fricative consonants were tested to demonstrate the effectiveness of the method with an acceleration factor of 3.

2004. MR Evaluation in Patients with Congenital Dysosmia Hui You1, Feng Feng2, Jian-Feng Liu2, Xue-Yan Wu2, Jian Wang, Zhengyu King 1Peking Union Medical College Hospital, Beijing, People's Republic of China; 2Peking Union Medical College Hospital, People's Republic of China

To study the MR imaging findings of congenital dysosmia, 47 patients with congenital dysosmia including 39 patients with Kallmann syndrome and 8 with isolated dysosmia, and 21 age-matched normal volunteers underwent high-resolution MRI examination. All the patients had abnormal findings in olfactory bulbs and tracts. And the pituitary gland was smaller and the stalk was thinner in patients with Kallmann syndrome than volunteers. MR can readily depict the malformation of olfactory bulbs and tracts in congenital dysosmic patients.

2005. Field-Corrected Dynamic Imaging of the Velopharyngeal Musculature During Swallow Charles A. Conway1, Youkyung Song1, David P. Kuehn1, Bradley P. Sutton1 1University of Illinois at Urbana-Champaign, Urbana, USA

Real-time dynamic MRI of swallowing is particularly difficult because field inhomogeneity due to air-tissue interfaces changes as the anatomy moves. The aim of this study is to reconstruct dynamic field-corrected images, allowing us to gain temporal resolution by lengthening readouts without paying the penalty of additional image distortion. This method has been applied to a spiral FLASH sequence for imaging the velopharyngeal musculature during swallow with 61 ms temporal resolution. Scans of healthy adults demonstrate the ability of MRI to compete with traditional methods of clinical swallowing evaluation including endoscopy and X-ray fluoroscopy.

2006. Magnetic Resonance Imaging in Orthodontics: Three-Dimensional Localization of Impacted Teeth Olga Tymofiyeva1, Kurt Rottner1, Florian Schmid1, Ernst-Juergen Richter1, Peter Michael Jakob1 1University of Wuerzburg, Wuerzburg, Germany

Impacted teeth are teeth that are unable to erupt properly and remain under the gum. They often become infected or damage neighbouring teeth. Information about three-dimensional positioning of impacted teeth is invaluable in orthodontic diagnosis and treatment planning. The purpose of this study was to assess the feasibility of MRI of three-dimensional localization of impacted teeth in children and adults. MRI yielded a clear separation between impacted teeth and the surrounding tissue, and the position and angulation of impacted teeth in all three spatial dimensions could be assessed.

2007. In Vivo Caries Imaging Using Contrast-Enhanced Dental MRI Olga Tymofiyeva1, Kurt Rottner1, Florian Schmid1, Ernst-Juergen Richter1, Peter Michael Jakob1 1University of Wuerzburg, Wuerzburg, Germany

For diagnosis of carious lesions and estimation of their extension X-ray imaging has been routinely used in clinical practice. However, the technique only provides two-dimensional projections, which yields only limited information regarding localization and size of the lesion. In this article the first in vivo demonstration of carious lesion visualization and quantification using contrast-enhanced dental MRI is presented. Advantages of this innovative technique for caries diagnostic include the three-dimensionality of lesion visualization and quantification, the possibility to determine relative position of the lesion in relation to the pulp and absence of ionizing radiation.

Poster Sessions

336

Alzheimer's Disease & Mild Cognitive Impairment Hall D Thursday 13:30-15:30

2008. Diffusion Tensor Imaging and Voxel-Based Morphometry Study in Mild Alzheimer's Disease Qin Chen1, Ling Zou, Qiang Yuan1, Zheng-Yan Li, Luo Ou-Yang, Wei-Wei Zhang, Li-Jun Jiang, Dong Zhou1, Qi-Yong Gong 1West China Hospital of Sichuan University, Chengdu, People's Republic of China

Despite many efforts to draw a clear cut picture of the disease, a comprehensive characterization of grey and whiter matter changes in mild Alzheimer's disease (AD) is still not available. In this study, we aimed to characterize the brain changes in mild AD by the combined used of VBM and DTI. Our results suggest atrophy of cortical and subcortical structures and nerurodegeneration of specific fibre tracts may contribute to neurological deficits in AD. This approach guide future research investigating the relation between the brain areas involved and the clinical features in different phases of the disease.

2009. DTI Measures at the Midline Corpus Callosum in Patients with Incipient and Mild Alzheimer′s Disease Julio Acosta-Cabronero1, Guy B. Williams1, Peter J. Nestor1 1University of Cambridge, Cambridge, UK

The corpus callosum (CC), which contains millions of inter-hemispheric axons, is known to become atrophic early in AD, and its integrity is assumed to be associated with global cognitive performance. In this study, we extracted several DTI measures at the midline CC, and compared their relationships with CC area, as a marker of disease-related atrophy, and with global cognitive data. Radial diffusivity exhibited the strongest correlation to brain atrophy, whereas global cognition was better predicted by mean diffusivity measures. We found that high diffusivity integrals were systematically better predictors of both atrophy and global cognition than mean ROI values.

2010. Location of Affected Pathways in MCI and AD Through FA Comparison Darryl H. Hwang1, Witaya Sungkarat1, Manbir Singh1 1University of Southern California, Los Angeles, California , USA

Study was conducted to detect common regions in the brain where FA was reduced both in MCI and AD when compared to normals, but reduced more in AD than MCI. Pathways in a normalized space were generated from these regions by sorting normalized DTI tractography. Resulting pathways are consistent with the biology of Alzheimer Disease.

2011. Characteristic Patterns of White Matter Disintegration in Frontotemporal Dementia and Alzheimer’s Disease by DTI Yu Zhang1, 2, Norbert Schuff1, 2, An-Tao Du1, Howard J. Rosen2, Joel H. Kramer2, Maria Luisa Gorno-Tempini2, Bruce L. Miller2, Michael W. Weiner1, 2 1Center for Imaging of Neurodegenerative Diseases, VA Medical Center, San Francisco, California , USA; 2University of California, San Francisco, California , USA

Alzheimer’s disease (AD) and frontotemporal dementia (FTD) are two common dementias but difficult to be differentiated. In this study, diffusion tensor imaging (DTI) was used with tractography-based analysis and global analysis in 13 AD patients, 12 FTD, and 13 control (CN) subjects. DTI analyses showed that FTD had significant lower fractional anisotropy (FA) than CN predominantly in the anterior (frontal) and temporal brain; AD had significant lower (FA) than CN predominantly in the posterior (parietal) and temporal brain. These distinct FA patterns of FTD and AD may aid the differential diagnosis between the two types of dementias.

2012. Decreased Olfactory Tract Fiber Integrity in Mild Cognitive Impairment as Revealed by Diffusion Tensor Imaging Donna J. Cross1, Yoshimi Anzai1, Jeffery Stevenson1, Kenneth R. Maravilla1, Elaine R. Peskind, Satoshi Minoshima1 1University of Washington, Seattle, Washington, USA

synopsis

2013. Decrease of Glutathione Levels in a Transgenic Mouse Model of Alzheimer’s Disease Expressing Both β-Amyloid and Tau Pathology Wen-Tung Wang1, Sang-Pil Lee1, Mary L. Michaelis2, In-Young Choi1 1University of Kansas Medical Center, Kansas City, Kansas, USA; 2University of Kansas, Lawrence, Kansas, USA

The levels of neurochemicals can be altered through various pathological mechanisms, thus providing insights into the disease progression. Neurochemical profiles were acquired from the hippocampus of triple-transgenic mice with mutations in APP, PS1, and tau using ultra-short echo time 1H MRS at 9.4 T. Our preliminary study showed significant decreases of glutathione, a critical antioxidant, in the 19 months old transgenic mouse brain in vivo, indicating increased oxidative stress in AD.

2014. Regional Myo-Inositol Concentration in Mild Cognitive Impairment and Alzheimer Disease Using 1H Magnetic Resonance Spectroscopic Imaging Malgorzata Siger1, 2, Norbert Schuff1, Xiaoping Zhu1, Michael Weiner1 1Veterans Administration Medical Center, San Francisco, California , USA; 2Medical University of Lodz, Lodz, Poland

In this study, we used spectroscopic imaging (MRSI) to determine whether both MCI and AD show systematic regional patterns of metabolite abnormalities in white matter and gray matter. Results of our study suggests vulnerability of white matter in the pathology of AD and MCI as indicated by widespread increased myo-inositol in white matter regions. Furthermore, increased myo-inositol may be an even more robust and sensitive marker for MCI and AD than NAA, which was not significantly reduced in white matter compared to aging

Poster Sessions

337

2015. Longitudinal 4T Magnetic Resonance Spectroscopy of the Hippocampus in Alzheimer Disease Patients on Galantamine Jacob Penner1, 2, Raul Rupsingh1, 2, Matthew Smith3, Jennie Wells, 23, Michael Borrie, 23, Rob Bartha1, 2 1Robarts Research Institute, London, Canada; 2University of Western Ontario, London, Canada; 3Lawson Health Research Institute, London, Canada

Short echo time LASER localized proton magnetic resonance spectroscopy at 4.0 Tesla was used to quantify the levels of glutamate (Glu), N-acetyl aspartate (NAA), and creatine (Cr) in ten newly diagnosed Alzheimer disease patients at baseline and after 4 months of Galantamine treatment. A significant increase was found in the Glu/NAA ratio (p < 0.05) after 4 months, while there were no significant changes in the ratio of Glu/Cr, the absolute Glu, NAA, or Cr concentrations, or cognitive scores.

2016. 1H MR Spectroscopy of the Cingulate Gyrus Reveals Evidence for Unique Neurometabolic Profiles for Amnestic and Non-Amnestic Mild Cognitive Impairment Andreana P. Haley1, Kathleen L. Fuchs2, Sarah Andrea Dunham3, Carol A. Manning2, Jack Knight-Scott3 1The University of Texas at Austin, Austin, USA; 2University of Virginia, Charlottesville, Virginia , USA; 3Children's Healthcare of Atlanta, Atlanta, Georgia, USA

In this work, we demonstrate that differences in regional metabolic patterns can improve the differentiation between amnestic and non-amnestic mild cognitive impairment. Proton MRS measurements in the anterior and posterior cingulate gyrus provide unique metabolic profiles for both diagnoses indicating these sub-types are also unique neuropathologies.

2017. Magnetic Resonance Imaging and Spectroscopy Measures of Cognitive Decline in Mild Cognitive Impairment and Alzheimer’s Disease Converters Brenda Lynn Bartnik Olson1, Matthew Wagner1, William Britt1, Wolff Kirsch1, Barbara A. Holshouser1 1Loma Linda University, Loma Linda, California , USA

This study compares global brain, white and gray matter volumes as well as cerebral metabolite levels and ratios in tracking cognitive decline in twenty MCI and 13 cognitively normal control subjects. Structural 3D T1-weighted MRI and single voxel 1H MRS of the posterior cingulated gyrus (PCG) studies were performed over a 2-year period with repeat studies approximately every 12 months and neurocognitive testing every 6 months. Results show that the conversion to AD is associated with an increased rate of GM loss and decreases in NAA and Glx levels, compared to cognitively normal aging adults. Baseline NAA and Glx levels had a higher predictive accuracy than tissue or CSF volume.

2018. Correlation Between Global Severity Scales in Cognitive Impairment (GDS and CDR) and Magnetic Resonance H1 Spectroscopy, Perfusion Weighed Imaging and Diffusion Weighted Imaging Jorge Humberto Davila Acosta1, Nicolas Nicolas Fayed1, Antonio Oliveros Cid1 1Hospital Quiron, Zaragoza, Spain

The clinical evaluation, the diagnosis and the following of patients with AD and MCI is very complex. The use of clinical tools as GDS and CDR help to classify these patients, to compare them and to evaluate the response to the treatment. Some studies have found a good correlation between these clinical scales and the pathologic stages in AD described by Braak. The use of MRS, PWI and DWI in patients with AD and MCI has showed structural and metabolic changes. These changes can help in the clinical evaluation of patients with AD and MCI if a good correlation with the clinical stages is demonstrated.

2019. Association Between the Apolipoprotein E ε4 Gene Polymorphism and Cerebral Ventricular Dilatation Measured from Serial Magnetic Resonance Imaging in Subjects Enrolled in the Alzheimer’s Disease Neuroimaging Initiative Sean M. Nestor1, Raul Rupsingh1, Vittorio Accomazzi, Michael J. Borrie2, Matthew Smith3, Jennie Wells2, Jennifer Fogarty2, Robert Bartha1 1Robarts Research Institute, London, Canada; 2University of Western Ontario, London, Canada; 3Lawson Health Research Institute, London, Canada

The current study compares ventricular dilatation between carriers for the apolipoprotien E ε4 allele (ε4+) and subjects with other polymorphisms (ε4-), in subjects with Alzheimer disease(AD) and mild cognitive impairment (MCI), over a short interval. Six-month longitudinal data were selected from the Alzheimer’s Disease Neuroimaging database, which included 502 subjects (elderly controls, MCI, and AD). Baseline and six-month unprocessed 3D T1-weighted MP-RAGE 1.5 Tesla MR images, neurocognitive, and genetic measures were acquired. Ventricular volume was computed using a semi-automated region-growing algorithm (Cedara Software). Ventricular dilatation was significantly greater in the AD ε4+ group compared to AD ε4- subjects (p< 0.05).

2020. Shifting Regional Atrophy Rates in the Progression from Normal Aging to Alzheimer’s Disease Quantified by Fluid Registration Jasper D. Sluimer1, Wiesje M. van der Flier1, Giorgos B. Karas1, Ronald A. van Schijndel1, Josephine Barnes2, Richard G. Boyes2, Keith S. Cover1, Silvia D. Olabarriaga3, Nick C. Fox2, Philip Scheltens1, Hugo Vrenken1, Frederik Barkhof1 1VU University Medical Center, Amsterdam, Netherlands; 2University College London, London, UK; 3Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands

In 64 patients with Alzheimer’s disease (AD), 44 patients with mild cognitive impairment (MCI) and 34 controls, we determined regional atrophy rates in six different brain regions by applying Fluid nonlinear registration software to 3D coronal MPrage images from two timepoints. In MCI, the temporal lobe shows the greatest atrophy rate. In AD patients, the medial temporal lobe shows an atrophy rate comparable to MCI, while the remaining part of the temporal lobe demonstrates an even higher rate of atrophy. Moreover, atrophy also accelerates in parietal and occipital lobes.

Poster Sessions

338

2021. Regional Atrophy Demonstrated in Alzheimer’s Disease and Mild Cognitive Impairment (MCI) Using Minimal Post-Processing Time David L. Henderson1, John Frederic Schenck1, Natalie A. Staples1, Earl A. Zimmerman2 1General Electric Global Research, Niskayuna, USA; 2Albany Medical College, Albany, USA

Quantitative T2-mapping holds great promise for increasing the utility of MRI in the management of neurodegenerative diseases (NDDs), such as Alzheimer's disease, which affect millions of patients. Although many studies have the potential of quantitative brain imaging, they usually require prohibitive levels of time-consuming postprocessing analysis to provide useful results. We show examples of semi-automated image analysis capable of quantifying regional brain atrophy in various NDDs that may greatly reduce this bottleneck and promote the widespread use of MRI in these conditions.

2022. Sodium MRI Enhancement of the Medial Temporal Lobe in Mild Alzheimer’s Disease Eric Albert Mellon1, David T. Pilkinton1, Reddy Shashank Beesam1, Christopher M. Clark1, Elias R. Melhem1, Walter R. Witschey1, Arijitt Borthakur1, Ravinder Reddy1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA

There is substantial interest in quantitative techniques for the study of Alzheimer’s Disease (AD) to track the progression of disease for both prognosis and to monitor new therapies for AD. Towards this, presented is a study of changes in the medial temporal lobes by sodium MRI within the brains of patients with AD versus non-demented elderly controls on a clinical 3T scanner. An optimized Gradient Recalled Echo readout shows a statistically significant 12% enhancement between 4 mild AD patients and 5 age-matched control subjects. Work is already underway to elucidate the mechanisms and specificity of this enhancement.

2023. T2 Relaxometry and Volumetry of Postmortem Human Hippocampi Robert John Dawe1, David A. Bennett2, Julie A. Schneider2, Sunil Vasireddi1, Konstantinos Arfanakis1 1Illinois Institute of Technology, Chicago, Illinois, USA; 2Rush University Medical Center, Chicago, Illinois, USA

One advantage of postmortem MRI over in vivo imaging is that the in vitro tissue can be held nearly motionless indefinitely, making it possible to perform very high resolution imaging. This opportunity is exploited in the current study. Thirty-eight cadaveric human brains were scanned, and the T2 values and volumes of the hippocampi were correlated with the subjects' MMSE scores and which hemisphere was imaged (right or left). It was found that in postmortem brain specimens, low MMSE scores are associated with lower hippocampal T2 values.

2024. Correlation of Increased R2 with B0 and Cognitive Status Sarah Pachtman1, Himachandra Chebrolu1, Charles Dennis Smith1, Peter Andrew Hardy1 1University of Kentucky, Lexington, USA

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2025. Quantitative Comparison of Cerebral Blood Volume Between Patients with Alzheimer's Disease and Elderly Controls Jinsoo Uh1, Kelly Lewis-Amezcua1, Kristin Martin-Cook1, Myron Weiner1, Ramon Diaz-Arrastia1, Hanzhang Lu1 1University of Texas Southwestern Medical Center, Dallas, USA

Recent study suggests that Alzheimer’s Disease (AD) is featured by vascular factors, which may be useful for better understanding and early marker of AD. Utilizing a novel MR technique, Vascular-Space-Occupancy (VASO)-MRI, we quantitatively assessed Cerebral Blood Volume (CBV) of the entire brain on mild AD patients compared with age-matched controls. In particular, we identified brain regions that show significant differences between the two groups using ROI and voxel-by-voxel analyses based on elastic co-registration. Our study revealed that mild AD patients manifest significant reduction of CBV by 10-20% particularly at limbic system and basal ganglia regions.

2026. Detaild FMRI Investigation of Multiple Cognitive Domains in Patients with Amnesic MCI delia Lenzi1, 2, Laura Serra3, patrizia Pantano1, eraldu Paulesu, franco Giubilei1, roberta Perri3, gian luigi Lenzi1, carlo Caltagirone3, emiliano Macaluso3, marco Bozzali3 1Universita"La Sapienza", Rome, Italy; 2Fondazione Santa Lucia, IRCCS , Rome, Italy; 3Fondazione Santa Lucia, IRCCS, Rome, Italy

Amnesic Mild Cognitive Impairment (a-MCI) is considered as a frequent prodromal state of Alzheimer’s disease. Aim of this study was to investigate, using fMRI, the patterns of activation in patients with a-MCI when performing multiple tasks that selectively engage specific cognitive domains. 15 patients with MCI and 10 sex- and age-matched group of healthy controls were studied during tasks assessing memory functions, spatial attention, and empathic ability. During all tasks there was a significantly increased activation in the same network observed in healthy controls. This might reflect an initial compensation that explains the maintenance of performance in patients with MCI.

2027. Direct Visualization of Senile Plaques Using Clinical Field-Strength MRI and a Cholesterol-Fed Rabbit Model of Alzheimer’s Disease John A. Ronald1, 2, Yuanxin Chen1, Lisa M. Bernas1, 2, Robert A. Hegele1, 2, Kem A. Rogers2, Brian K. Rutt1, 2 1Robarts Research Institute, London, Canada; 2University of Western Ontario, London, Canada

We demonstrate a novel model of Alzheimer’s disease by feeding rabbits a low-level cholesterol diet for extended periods of time. These animals develop extracellular beta-amyloid rich plaques similar to compact plaques found in humans, and these plaques also reliably accumulate iron. High-resolution MRI of excised brains revealed signal voids throughout the brain parenchyma that directly correlated to iron-laden plaques in matched tissue sections. Minimal voids were seen in control brains. This is both the first successful attempt at direct imaging of plaques formed in a large animal model and first successful clinical field-strength imaging of plaques in any model.

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2028. Improved Magnetic Resonance Microimaging of Individual Amyloid Plaques in Alzheimer's Transgenic Mice Ryan Chamberlain1, Denise Reyes2, Geoffry L. Curran2, Thomas M. Wengenack2, Joseph F. Poduslo2, Michael Garwood1, Clifford R. Jack2 1University of Minnesota, Minneapolis, Minnesota, USA; 2Mayo Clinic College of Medicine, Rochester, Minnesota, USA

One of the principal pathologies of Alzheimer’s disease is amyloid plaques, the reduction of which has been identified as a major therapeutic objective. Plaques appear hypointense relative to background tissue on both T2- and T2

*-weighted images. The major limitations of existing approaches are long scan time and low CNR. This investigation analyzes the ability to increase the CNR over a previously verified spin echo sequence by summing multiple spin echoes and using multiple spin echo susceptibility weighted imaging.

2029. Comparison of Amyloid Plaque Characteristics in Transgenic Mouse Models of AD Using MR Microscopy Palamadai Nilakantan Venkatasubramanian1, 2, Gheorghe Iordanescu1, Alice M. Wyrwicz1 1ENH Research Institute, Evanston, Illinois, USA; 2Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA

Amyloid plaques in two APP transgenic mouse lines were imaged directly without the use of external contrast agent. Plaque characteristics such as size, number and regional distribution were different between the two transgenic lines.

2030. Iron is a Prerequisite for Direct Visualization of Alzheimer’s Plaques in Animal Models Yuanxin Chen1, John A. Ronald1, 2, Lisa M. Bernas1, 2, Robert A. Hegele1, 2, Kem A. Rogers2, Brian K. Rutt1, 2 1Robarts Research Institute, London, Canada; 2University of Western Ontario, London, Canada

Our lab has shown that direct visualization of Alzheimer’s disease (AD) plaques in a cholesterol-fed rabbit model of AD is possible using clinical-field strength ex vivo MRI. These rabbits formed plaques with dramatic iron accumulation. Here, we performed MRI in an additional two AD models including rabbits fed a high-cholesterol diet for a short time and an AD transgenic mouse. We demonstrate that amyloid plaques formed in these models without iron deposits were not detectable on MR imaging. This suggests that the ability to detect AD plaques in animal models is due to their clear association with excess iron.

2031. Overexpression of SOD-2 Rescues Reduced Cerebral Blood Flow in the Tg2576 (APP) Mouse Model of Alzheimer’s Disease Samir Kamalesh Amin1, Cynthia Massaad1, Lingyun Hu1, Eric Klann2, Robia G. Pautler1 1Baylor College of Medicine, Houston, Texas, USA; 2New York University, New York City, New York, USA

A-beta peptide accumulation is pivotal in Alzheimer’s disease (AD) pathogenesis. Few studies have addressed A β involvement in oxidative impairment of cerebrovascular regulation in AD. We studied this aspect of A β pathogenesis using transgenic mice with Flow-sensitive Alternating Inversion-Recovery EPI arterial spin labeling. We wanted to determine if overexpression of the reactive oxygen species scavenger SOD-2 in APP mice leads to reversal of cerebral blood flow attenuation. We found that oxidative damage on cerebrovasculature occurs early in the pathogenesis and can be “rescued” with SOD-2 overexpression. Our present findings support the idea that ROS formation precedes plaques in the AD pathogenesis.

2032. Cerebrovascular Alterations in APP23 Transgenic Mice Modelling Alzheimer’s Disease Studied Non-Invasively by MRI Nicolau Beckmann1, Stefan Zurbruegg1, Catherine Cannet1, Christelle Gérard1, Dorothee Abramowski1, Karl-Heinz Wiederhold1, Matthias Staufenbiel1 1Novartis Institutes for BioMedical Research, Basel, Switzerland

MRI was used to detect in APP23 mice the effects of cerebral amyloid angiopathy. Endorem® was administered i.v. 24h before imaging. Foci of signal attenuations became apparent in the brain cortex as well as in thalamic regions of 16-month-old APP23 mice. An age-dependent increase in the number of foci displaying attenuated signal was observed in older animals. With a few exceptions, these foci were absent in age-matched, wildtype littermate controls. Histology revealed that, at sites of signal loss detected by MRI, iron was localized in or around damaged vessels, entrapped in microglia/macrophages.

2033. Geriatric Rhesus Monkeys Have in Vivo Proton MRS Signatures of Human Alzheimer's Disease Rose-Ann Blenman1, Marie Holahan1, Denise Welsh1, Jacquelynn Cook1, Richard Hargreaves1, Donald Williams1 1Merck & Co. Inc., West Point, Pennsylvania, USA

Proton MRS biomarkers were assessed in young adult and geriatric Rhesus monkeys. Since geriatric Rhesus monkeys (≥ 24 years) have been characterized as models of neurodegenerative disease, our hypothesis was that geriatrics would have altered biochemical profiles suggesting neuronal degeneration and glial activation. MRS in the posterior cingulate of geriatric Rhesus showed that NAA/tCr decreased by ≈15%, mI/tCr increased by ≈30%, and tCho/tCr decreased by ≈20% as compared to the young adult monkeys (≤15 years). Results also showed that NAA/tCr, mI/tCr and tCho/tCr are highly correlated with age and that tCho/tCr is correlated with NAA/tCr and NAA/mI.

2034. Interhemispheric Visual Integration in Alzheimer's Disease: Decrease of FMRI BOLD Response in VP/V4 Areas Laurent Uldry1, Isabelle Bourquin1, Andrea Brioschi1, Joseph Ghika1, Philippe Maeder1, Reto Meuli1, Eleonora Fornari1 1Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland

During an fMRI study, we compared 15 newly diagnosed Alzheimer (AD) patients with 15 age-matched subjects and investigated higher-order visual areas to detect AD-related malfunction before the appearance of clinical signs. Our paradigm addresses visual interhemispheric integration functions, with stimuli obeying (IG) or not (OG) the Gestalt principle. We found that the interhemispheric integration process (IG vs. OG contrast) induced BOLD increase within VP/V4 areas. AD patients showed the same activation pattern as control subjects, but characterized by a reduction of intensity and extent, possibly due to an already decreased myelination of cortico-cortical connections involved in spatial integration.

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2035. Cerebral Blood Flow Measurement in Alzheimer Disease and Mild Cognitive Impairment Using QUASAR and 3T MRI Takashi Yoshiura1, Tomoyuki Noguchi1, Akio Hiwatashi1, Osamu Togao1, Koji Yamashita1, Eiki Nagao1, Hidetaka Arimura1, Tomoyuki Okuaki2, Ivan Zimine2, Marc van Cauteren2, Hiroshi Honda1 1Kyushu University, Fukuoka, Japan; 2Philips Medical Systems, Japan, Tokyo, Japan

Nine patients with MCI, seven patients with AD and seven normal subjects were studied using a quantitative ASL pulse sequence (QUASAR) and 3T MRI. Absolute CBFs were measured in whole gray matter region, bilateral thalami and bilateral inferior parietal (IP) cortices. Relative CBF values of bilateral IP cortices normalized by whole gray matter CBF and by thalamic CBF were also obtained. Both absolute and relative CBFs in the right IP cortex were significantly decreased in AD group. Moreover, relative CBF in right IP normalized by whole gray matter CBF was significantly decreased in MCI group in comparison with normal group.

Normal Human Brain: Connections & Activations Hall D Monday 14:00-16:00

2036. Pre-Attentive Processing of Contour Deviance in Musicians Benedikt Habermeyer1, Marcus Herdener, Fabrizio Esposito, Caroline C. Hilti, Markus Klarhoefer, Francesco di Salle, Klaus Scheffler, Katja Cattapan-Ludewig, Erich Seifritz 1University of Basel, Basel, Switzerland

Impact of musical expertise on functional capabilities of frontal brain regions remains elusive. We used fMRI to investigated differential BOLD responses between musicians and non-musicians. Musicians showed a different activation pattern with an activation in the right ventromedial prefrontal cortex, bilateral inferior frontal gyrus and left superior temporal gyrus. BOLD signal showed a significant correlation to behaviourally tested ability to discriminate changes in sound patterns. Our data shows that prefrontal cortex is engaged in melody processing. Activation in the ventromedial prefrontal cortex supports the hypothesis that this area is a node that is important for binding music with memories within an broader melody-responsive network.

2037. Alcohol-Induced Changes in the Hemodynamic Response Function in Event-Related FMRI : Evidence for Slow Down of Neurovascular Coupling Michael Luchtmann1, Tobias Moench1, Maurice Hollmann1, Katja Jachau1, Sandra Boettcher1, Johannes Bernarding1 1Otto-von-Guericke University of Magdeburg, Magdeburg, Germany

The influence of ethanol on human neurophysiology was examined by methods of functional neuroimaging. The individual hemodynamic response functions (HRF) of 15 volunteers were observed within four different brain areas (left and right motor cortex, supplementary motor area (SMA), visual cortex) for changes caused by acute alcohol intoxication. With a mean blood alcohol concentration of 0.82 ‰ all subjects showed clear changes in shape of HRF, whereby most significant alteration was observed in SMA. The presented results may be a hint for the known effect of alcohol to impair initiation of complex motor actions.

2038. Heart-Brain Interaction: An FMRI Study of the Human Brain Response to the Cold Pressor Test Raphael Delano Hazel1, Deepu Alexander1, Edwin Estrada1, Marguerite Roth1, William Schapiro1, Mark Wagshul2, Nathaniel Reichek1 1St Francis Hospital, Roslyn, New York, USA; 2Stony Brook University, Stony Brook, New York, USA

The goal of this study was to establish the extent and characteristics of the heart-brain interaction through the neurogenic response to the CPT using fMRI. Activity was observed in the insular cortex in all subjects, but activity in the region of the brainstem involving the NTS was recorded in only two subject during the 60s CPT. Early observations suggest a progressive brain response to the cold stress.

2039. Compensatory Recruitment After 36 H Total Sleep Deprivation and the Relationship with Executive Control Yong-cong Shao1, Bo Wen2, En-mao Ye1, Jian-lin Qi1, Guo-hua Bi1, Dan-Min Miao3, Lin Ma2, Zheng Yang1 1Beijing Institute of Basic Medical Sciences, Beijing, People's Republic of China; 2General Hospital of People's Liberation Army of China, Beijing, People's Republic of China; 3the Forth Military Medical University, Xi'an, People's Republic of China

Executive function relying on inhibition is affected by total sleep deprivation (TSD). In this study, we investigated the influence of TSD on response inhibition using combined behavioral, fMRI techniques and a visual Go/No-go task. Results indicated that sleep deprivation lowered Go/No-go sustained, task-related activation of ACC regions. The significant activation of prefrontal lobe had shown a along with the decline performance, more attention resources were needed to perform the Go/No-go task after TSD. These results suggested that TSD were accompanied with an impact on brain functions of response inhibition and required more anticipation of prefrontal lobe for compensatory recruitment.

2040. Increased Change in Water Dffusion MRI Following Low Frequency Repetitive Transcranial Magnetic Stimulation Mitsunari Abe1, Tatsuya Mima1, Nobukatsu Sawamoto, Shin-ichi Urayama1, Toshihiko Aso2, Denis Le Bihan2, Hidenao Fukuyama1 1Human Brain Research Center, Kyoto Grad. Sch. Med., Kyoto, Japan; 2NeuroSpin, France

Low frequency repetitive transcranial magnetic stimulation (rTMS) was performed within a 3T MRI scanner while diffusion-weighted MR images were collected, before and after the stimulation. Following the rTMS, water diffusion was significantly increased in bilateral motor-related areas. The water diffusion increase in the stimulated primary motor cortex was recovered within 10 min while that of some remote areas in contralateral hemisphere remained for 10-20 min. These findings support that rTMS conditioning effects (cortical inhibition) induce transient structural changes in extended motor network systems.

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2041. Effects of Directional Resolution in Diffusion Tensor Tractography: Comparisons on Total Fiber Volume and Fiber Consistency Yen-Wei Cheng1, Ming-Chung Chou1, Hsiao-Wen Chung1, Cheng-Yu Chen2, Yi-Jui Liu3 1National Taiwan University, Taipei, Taiwan; 2Tri-Service General Hospital, Taipei, Taiwan; 3Feng Chia University, Taichung, Taiwan

To keep the scan time almost the same, DTI data were acquired separately using direction resolution of 6, 15 and 32 at NEX of 5, 2 and 1 .We found that 32 directional DTI had the largest traced fiber volume and highest fiber consistency. It suggests the directional resolution is more important than image SNR in terms of traced fiber volume and fiber consistency. Our results showed that the increase of diffusion directions in DTI not only impacts the precision and accuracy of in vivo fractional anisotropy, mean diffusivity, and principal eigenvector, but also improves the diffusion tensor tractography results.

2042. Reproducibility of Fractional Anisotropy and Mean Diffusivity in Diffusion Tensor Imaging at 3.0 T Yundi Shi1, Sarang Joshi1, James N. Lee1, William R. Marchand, 12, Esther Rashkin1, Edward W. Hsu1 1University of Utah, Salt Lake City, Utah, USA; 2Department of Veterans Affairs, VISN 19 MIRECC, Salt Lake City, Utah, USA

DTI has been widely used in brain study, which made reproducibility of the measurements essential in order to perform comparison neuroimaging techniques. This abstract described our recent study using Fisher-Pitman permutation test to compare two DTI datasets acquired at 3.0T, different scan time with the same protocol voxel-by-voxel, with the goal to evaluate statistically the significant difference between scans as well as locate the voxels with detectable difference. Results reveal that DTI measurements including FA and mean diffusivity are highly reproducible. Furthermore, the significant different voxels were found to be mostly at the brain periphery, which could be caused by imperfect registration or partial volume effects.

2043. Grey Matter Changes and Motor Learning of Meaningful and Meaningless Actions: A Tensor-Based Morphometry Study Elisabetta Pagani1, Antonia Ceccarelli1, Maria A. Rocca1, Roberto Gatti1, Andrea Falini1, Massimo Filippi1 1Scientific Institute and University Ospedale San Raffaele, Milan, Italy

Cross-sectional voxel based morphometry studies have demonstrated learning-dependent changes in the adult human brain. We performed tensor based morphometry (TBM) on 3D T1-weighted fast field echo images in 22 healthy subjects at three different time points: 1) before motor training; 2) at the end of two weeks of training and, 3) three months later. During motor training, 11 subjects learned meaningful (MF) actions, and the other 11 meaningless (ML) actions. We demonstrated that learning of MF and ML actions might result in structural GM changes in different brain areas which are part of specific neuronal networks.

Pediatric Normal Brain: Multimodality Hall D Tuesday 13:30-15:30

2044. Observation of Intrinsic and Extrinsic Mechanisms During Cortical Convolution Development Latha Srinivasan1, 2, Hui Xue1, Serena J. Counsell1, Joanna M. Allsop1, Julie A. Fitzpatrick1, Giuliana Durighel1, A David Edwards1, Mary A. Rutherford1, Daniel Rueckert1, Joseph V. Hajnal1 1Imperial College London, London, UK

Convolutions are the most striking feature of third trimester cortical development. 120 preterm infants were studied between 25 and 50 weeks gestation using a neonatal specific cortical segmentation and reconstruction technique. The cortical surface area expanded exponentially until 36 weeks after which the surface area and volume increased proportionally. Curvature analysis of the inner cortical surface revealed that the early surfeit in surface area corresponded with an increase in the intrinsic curvature whereas the later proportional growth mirrored an increase in the extrinsic curvature, suggesting that both intrinsic and extrinsic mechanisms are active albeit at different phases of cortical gyrification.

2045. MRI Children Atlas Based on a Robust Estimator Juan José Ortiz1, Leopoldo José Gonzalez1, Roberto Emmanuele Mercadillo1, Fernando Alejandro Barrios1 1Universidad Nacional Autonoma de Mexico, Queretaro, Mexico

Brain atlases are used to project and localize activated structures in fMRI or statistical differences in BVM. Brain atlases or templates are averaged 3D image volumes projected into stereotactic space, generated from one or several subjects using different medical imaging techniques. Children templates pose interesting challenges since structure and spatial localization differs from other children during development and form the adult brain. In this work a one children template was generated using the mode as robust statistical estimator, and three different realignment processes are compared.

2046. Age and Regional Dependent Changes of Glutamate in Human Brain: In Vivo Quantitation with MR Spectroscopy Ashok Panigrahy1, Jane Tavare1, Marvin D. Nelson1, Floyd H. Gilles1, Istvan Seri1, Stefan Bluml1, 2 1Childrens Hospital Los Angeles/USC, Los Angeles, California , USA; 2Rudi Schulte Research Institute, Santa Barbara, California , USA

Age-dependent normal changes of glutamate concentrations were determined in 416 subjects with normal MRI and unremarkable clinical follow-up ranging in age from 25 weeks post-conceptional age (15 weeks premature) to 20 years. Glutamate concentrations increased from 3.7 ±2.0 mmol/kg at term to adult levels of 8.6±1.1mmol/kg in parietal white matter and from 4.4±1.5 mmol/kg to 12.9±1.3mmol/kg in occipital grey matter within the first year of life. The highest rate of net glutamate synthesis in WM was observed at 6 weeks after birth (0.46mmol/kg/week) and in grey matter 12 weeks after birth (0.36mmol/kg/week).

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2047. T2 Relaxometry of Normal Pediatric Brain Development Ilana Ruth Leppert1, C Robert Almli, Robert C. McKinstry, Robert V. Mulkern, Carlo Pierpaoli, Michael J. Rivkin, Gilbert Bruce Pike1 1Montreal Neurological Institute, Montreal, Canada

This work establishes normal age-related changes in MR T2 relaxation time constants using data collected as part of the NIH MRI Study of Normal Brain Development. The main finding, based on over 200 subject scans, is the parametrization of the mono-exponential evolution of T2 in several brain regions for children aged 0 to 4.5 years. This behavior is believed to reflect the rapid water content changes as well as myelination processes during neonatal brain development. These results represent a subset of a publicly available normative pediatric MRI database, providing a basis for comparison for studies assessing normal brain development and deviation due to various neurological disorders.

2048. Brain Development of Neonatal Guinea Pigs in Vivo Measured by Diffusion Tensor Imaging at 9.4 T Jieun Kim1, In-Young Choi1, Yafeng Dong1, Carl P. Weiner1, Sang-Pil Lee1 1University of Kansas Medical Center, Kansas city, Kansas, USA

Guinea pigs are ideal for studying the growth and development of the brain due to their precocious neurological development. DTI provides good endogenous brain tissue delineation contrast. We obtained quantitative measurement for brain white matter development in postnatal guinea pigs using DTI in vivo. This work could pave a way to study abnormalities of brain development and to understand the underlying mechanisms of the most common cause of fetal brain damage, chronic fetal hypoxemia.

2049. Comparative DTI Study of Preterm and Normal Newborns : SPM and ROI Analyses Paola Scifo1, 2, Cristina Baldoli1, 2, Silvia Pontesilli1, 2, Federica Navarra1, 2, Roberta Scotti1, 2, Antonella Poloniato1, Giuseppe Scotti1, 2, Ferruccio Fazio1 1Scientific Institute H San Raffaele, Milan, Italy; 2Università Vita-Salute San Raffaele, Milan, Italy

In this work, we show a comparative DTI study between a group of normal newborns and a group of preterm newborns these last acquired three times, at different stages of development. Analyses have been performed both on voxel-by-voxel basis and with ROIs. Results show a delayed myelination in preterm newborns with respect to normal subjects but this evidence is reduced along time. Comparison between SPM and ROI analyses show congruent results.

2050. Diffusion Tensor Imaging of Normal White Matter Maturation from Late Childhood to Young Adulthood: Voxel-Wise Evaluation of Mean Diffusivity, Fractional Anisotropy, Radial and Axial Diffusivities Deqiang Qiu1, Li-Hai Tan1, Pek-Lan Khong1 1The University of Hong Kong, Hong Kong, People's Republic of China

Using diffusion tensor MR imaging(DTI) and advanced voxelwise analysis tools, we aim to study changes of diffusivities and anisotropy of white matter in three age groups from late childhood to young adulthood (7.4yrs +/-0.3, n=24, 10.3yrs +/-0.5, n=27, 22.8yrs +/-2.3, n=24). We found predominantly increased FA and decreased MD with increasing age in regions of cerebellar white matter, right temporal white matter and a large portion of the superior frontal and parietal white matter driven by both the reduction of radial diffusivity and axial diffusivity but the latter to a lesser extent.

2051. Lateralization of the Superior Longitudinal Fasciculus Across the Age Span and Its Relation to Cognitive Abilities in Children Catherine Lebel1, Christian Beaulieu1 1University of Alberta, Edmonton, Canada

The superior longitudinal fasciculus (SLF) is a white matter tract involved in many cognitive tasks. This study used diffusion tensor tractography to investigate SLF asymmetry in 223 healthy, right-handed subjects aged 5-58 years, and a subgroup of 59 children 5-13 years who also underwent cognitive assessment. We tracked the direct SLF segment in each hemisphere, and classified subjects as left-lateralized, symmetric, or right-lateralized. Most individuals were left-lateralized; however, some individuals, mainly children, showed rightward asymmetry. Symmetric children outperformed left-lateralized children on five of seven cognitive assessments and right-lateralized children on three tasks, suggesting symmetric arrangements offer a certain cognitive advantage.

2052. Relations Between White Matter Integrity and Working Memory in Children and Adolescents Donald Mabbott1, 2, Joanne Rovet1, 2, Conrad Rockel1 1The Hospital for Sick Children, Toronto, Canada; 2University of Toronto, Toronto, Canada

In this diffusion tensor study we examined regional differences in the relations between age and hemispheric white matter fractional anisotropy (FA) and tested the relations between FA, age, and working memory in 36 typically developing children. FA was calculated for 12 regions of hemispheric white matter. The effect of age on FA was stronger for frontal-parietal than posterior white matter. Only right inferior-frontal regions contributed uniquely beyond the effect of age in accounting for working memory performance. Our findings are consistent with the growth of regional white matter organization as playing an important role in increased working memory with age.

2053. Mapping of Paediatric Motor Function and Structure Using Magnetoencephalography (MEG) and Diffusion Tensor Imaging (DTI) Donald Mabbott1, 2, William Gaetz1, Elysa Widjaja1, Sonya Bells1, Conrad Rockel1 1The Hospital for Sick Children, Toronto, Canada; 2University of Toronton, Toronto, Canada

MEG was used to identify motor fields for the left and right hands in young children and these activations were used as seeds for probabilistic tractography of the associated white matter pathways. Quantitative measures of the integrity of these tracts were calculated and we evaluated whether differences existed between the dominant and non-dominant hands, and age-related changes were evident. The Motor Field was localized to the hand area of pre-central gyrus with tractography delineating cortical-spinal tracts. FA for the dominant hand cortical-spinal tract was greater than for the non-dominant hand and age related changes were evident for the dominant hand only.

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2054. Perfusion Imaging of Normal Brain Development from Childhood to Young Adulthood Hengyi Rao1, Sumei Wang1, Joan Giannetta2, Kim M. Cecil3, John VanMeter4, Thomas A. Zeffiro5, Hallam Hurt2, John A. Detre1, Jiongjiong Wang1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA; 2the Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA; 3Cincinnati Children's Hospital, Cincinnati, Ohio, USA; 4Georgetown University Medical Center, Washington DC, USA; 5Massachusetts General Hospital, Boston, Massachusetts, USA

Continuous arterial spin labeling (CASL) perfusion MRI was used to examine the typical development of cerebral blood flow (CBF) in a cohort of 90 healthy pediatric (5-16yrs) and young adult (18-30yrs) subjects. The global CBF showed a monotonic decrease with age. After adjusting the global CBF differences, significant relative regional CBF increases with age were found in the cingulate, angular, superior temporal and frontal cortex, which may reflect the later maturation of these brain regions. These results support the feasibility and potential of ASL perfusion MRI for longitudinal neuroimaging studies to follow the functional development of the growing human brain.

2055. Significant Differences Found in the Distribution of Pulsatile Flows in the Preterm Infant Brain Compared to the Adult Brain Gary P. Zientara1, Janet S. Soul2, Kate McCann1, 3, Adre du Plessis2, Hiam Bassan2, Richard L. Roberston Jr. 2, Stephan E. Maier1, Ferenc A. Jolesz1, Lawrence P. Panych1, Steven A. Ringer1 1Harvard Medical School and Brigham and Women's Hospital, Boston, Massachusetts, USA; 2Harvard Medical School and Children's Hospital Boston, Boston, Massachusetts, USA; 3University of Maine at Orono, Orono, Maine, USA

Previously, we described a rapid EPI-based method for using slice inflow to investigate frequency band-specific pulsatile flow in the brain, and indicated its importance in revealing the physiology of the preterm infant. In a study of 30 preterm infants, we computed frequency band-specific pulsatile flow images, and then computed the distribution of flow-related signal. Our findings reveal that throughout the age range studied, the frequency distribution of pulsatile flow in the preterm infant brain is dominated by very low and low frequency components, the opposite of that described in published studies of flow in the adult brain.

2056. PROPELLER FSE T2-Weighted Imaging in Pediatric Brain Imaging: Can We Replace Standard FSE T2-Weighted Imaging? Alexandra Talia Vertinsky1, Erika Rubesova2, Michael Vladimir Krasnokutsky3, Sabine Bammer2, Jarrett Rosenberg2, Allan White2, Patrick David Barnes2, Roland Bammer2 1University of British Columbia, Vancouver, Canada; 2Stanford University, Stanford, California , USA; 3Madigan Army Medical Center, Tacoma, USA

PROPELLER is a relatively new method of reducing motion artifact, which produces similar motion reduction to SSFSE while providing improved image contrast. A comparative evaluation of T2w-FSE and T2w-PROPELLER on image quality and diagnostic yield was performed on a consecutive series of pediatric patients. Although no substantial benefit in diagnostic confidence was observed, T2w-PROPELLER FSE offers sufficient diagnostic information that it may be substituted for conventional FSE T2 in pediatric exams in order to reduce motion and improve image quality. However, caution is required in using PROPELLER to identify blood products and further studies are warranted to investigate the nature of this difference in sensitivity.

Pediatric Brain: Metabolic, Leukodystrophy Hall D Wednesday 13:30-15:30

2057. Magnetic Resonance Spectroscopy in Patients with Fabry and Gaucher Disease Stephan Gruber1, Margareta Holub2, Wolfgang Bogner1, Andreas Stadlbauer3, Martin Krssak2, Olaf Bodamer2 1Medical University of Vienna, Vienna, Austria; 2Medical University of Vienna, Austria; 3Landesklinikum St. Poelten, Austria

Fabry and Gaucher disease are rare, progressive, inherited disorders of glycosphingolipid metabolism that affect multiple organ systems. Aim of this studies was to investigate central nervous system involvement using MR spectroscopic imaging. Absolute metabolite values revealed no differences between Fabry- and Gaucher- (Type 1) patients and controls. Previous work reported increased Cho in a Gaucher Type 1 patient, which can be explained by using different echo time and inappropriate control group. In this study we found significantly decreasing NAA/Cho in all three goups measured (between 5 and 8% per decade) pointing out the importance of sex- and age-matched controls.

2058. Quantitative Diffusion Tensor Imaging and T1 Relaxometry in Niemann-Pick C Disease christabel ec Lee1, David M. Thomasson1, Nicole M. Yanjanin2, Eva H. Baker2, Forbes D. Porter2 1National Institutes of Health, Bethesda, Maryland, USA; 2National Institutes of Health, Bethesda, Maryland, USA

We imaged the brains of 14 patients with Niemann-Pick C disease using diffusion tensor imaging and T1 relaxometry to develop MR based quantitative measurements for the assessment of disease severity. We correlated patients’ symptom-based severity scores with fractional anisotropy (FA), apparent diffusion coefficient (ADC), and T1 relaxation time. For DTI, we found 8 different anatomical locations had statistically significant correlation to the symptom-based severity score, while for T1 relaxation, we found statistically significant correlations at 2 locations. We suggest DTI may be more sensitive than T1 relaxometry as a quantitative measurement for assessment of this disease.

2059. MRS Measurement of Disease Severity in Niemann-Pick Disease Type C Eva H. Baker1, Nicole M. Yanjanin2, Forbes D. Porter2 1Clinical Center, NIH, Bethesda, Maryland, USA; 2National Institute of Child Health and Development, NIH, Bethesda, Maryland, USA

Niemann-Pick disease, type C is an autosomal recessive lipid storage disorder involving liver, spleen, lungs, and brain. Onset of symptoms is usually in childhood; rate of progression is variable, and patients can survive into adulthood. Neurologic findings follow a progressive degenerative course. Brain imaging findings are nonspecific; MRI is often normal. Seeking an MR-based measure of disease severity, we examined metabolite levels at 4 locations in the brain, and found statistically significant correlation between NAA+NAAG and symptom-based severity score at 2 locations in the cerebellum. Thus, NAA+NAAG levels could prove useful for monitoring disease progression and response to treatment.

Poster Sessions

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2060. Quantitative T2 Mapping in a Niemann-Pick Type C Mouse Model John Totenhagen1, Katherine Thome1, Christine Howison1, Robert P. Erickson1, Theodore P. Trouard1 1University of Arizona, Tucson, USA

Niemann-Pick Type C (NPC) disease is a fatal autosomal recessive neurodegenerative disorder with no current effective treatments. A quantitative measure of the progression and response to treatment of NPC disease is desired for evaluation of NPC therapies. In this work we have investigated quantitative T2 mapping in a mouse model of NPC disease. Mice were imaged with a radial FSE sequence and T2 maps created from individual radial datasets. Differences in T2 values were measured in white matter regions of NPC, transgenic NPC and control mice.

2061. 1H MR Spectroscopy of Creatine Deficiency Syndrome Caused by a Novel Mutation Monika Dezortova1, Filip Jiru1, Milan Hajek1, Vera Malinova2, Jan Petrasek1, Milan Jirsa1 1Institute for Clinical and Experimental Medicine, Prague, Czech Republic; 21st Faculty of Medicine, Charles University, Prague, Czech Republic

Two siblings (male and female) were repeatedly examined using 1H MR spectroscopic imaging. First, MR spectra showed significantly reduced creatine concentration only in the male, whereas other metabolites were in normal range. Creatine concentration calculated from female’s spectra was near the lower control limit. Initial hypothesis of creatine transporter deficiency was proved when, one year later, creatine supplementation did not improve clinical status of the male and another decrease in creatine was observed in his spectra. Our findings strongly indicated the diagnosis which was confirmed by finding a novel nonsense mutation del c.219C in exon 1 of the SLC6A8 gene.

2062. L-2-Hydroxyglutaric Aciduria: Pattern of MRI Abnormalities in 53 Patients Marjan Elisabeth Steenweg1, N M. Verhoeven1, C Jakobs1, G S. Salomons1, M S. van der Knaap1 1VU University Medical Center, Amsterdam, Netherlands

L-2-hydroxyglutaric aciduria is a rare, inherited metabolic disorder. Affected individuals only have neurological manifestations. We studied the brain-MRI pattern associated with the disease. Using a standard protocol for reviewing the MR images we found a consistent pattern of signal abnormalities. The most severe white matter abnormalities were seen in the frontal, subcortical white matter. In addition, bilateral involvement of the globus pallidus, caudate nucleus, putamen, and dentate nucleus was almost invariably seen. Over time the white matter abnormalities showed antero-posterior and centripetal progression and atrophy of the cerebral white matter occurred.

2063. MRI Findings and Neuropathology in a Mouse Model of Maple Syrup Urine Disease Jelena Lazovic1, Kathryn LaNoue2, Gregg Homanics3, William Zinnanti2 1California Institute of Technology, Pasadena, California , USA; 2Pennsylvania State University, Hershey, Pennsylvania, USA; 3University of Pittsburgh, Pittsburgh, Pennsylvania, USA

A mouse model of intermediate maple syrup urine disease (iMSUD) is introduced. Elevated to highly elevated T2-values were present in the striatum, thalamus, occipital lobes and cerebellum indicating irreversible injury. Immunohistochemistry revealed intense vacuolation similar to spongiform changes throughout these regions, accompanied by severe loss of neuronal processes. We propose that prominent vacuolation rather than dysmyelination are contributing to increased signal on T2-weighted images in the iMSUD mouse model. The MSUD associated neuropathology was minimized when animals were placed on low branched chain amino acids (BCAA) diet, indicating the importance of BCAA control to prevent MSUD related brain injury.

2064. Effect of Standard Oral Aminoacid Mixtures on Cerebral Phenylalanine Content and the Dynamics of Blood-Brain-Barrier Dynamics in PKU Patients Roland Kreis1, Karin Zwygart1, Thomas Lutz2, Chris Boesch1, Joachim Pietz2 1University Berne, Berne, Switzerland; 2University of Heidelberg, Heidelberg, Germany

Phenylketonuria is normally treated with dietary protein restriction and supplementation with the other amino acids (AA). It was shown earlier that oral substitution with high loads of large neutral AA can hinder the entry of additional phenylalanine (Phe) into brain for several hours. We now show with MRS that the same short-term effect can be reached with commercial AA powder in realistic dosage and that regular AA supplementation leads to lowering of cerebral steady state Phe levels on the long run because of its modulating influence on the BBB transport, which is described with asymmetric Michaelis Menton kinetics.

2065. Directional Diffusivity as an MR Biomarker of Axonal Injury in Leukodystrophy Tammie LS Benzinger1, Chin-I Chen, 2, Agus Priatna, Junqian Xu, Peng Sun1, Amy Lee, Anne Cross, Sheng-Kwei Song1, Soe Mar 1Washington University in Saint Louis, St. Louis, Missouri, USA; 2Wangang Municipal Hospital, Taipei, Taiwan

Luekodystropy represents a broad category of genetic white matter diseases, characterized by varying degrees of myelin and axonal damage, depending upon the subtype. Frequently, these patients present for MR imaging without a known diagnosis. Although leukodystrophies have a very classic appearance on MRI, identifying the correct genetic subtype, which is critical for prognosis, is currently difficult by MRI alone. Here, we use axial and radial directional diffusivity to estimate the degree of axonal versus myelin damage, thus allowing for more precise diagnosis and prognosis.

2066. Multi-Slice Spectroscopic Imaging of Late Infantile Metachromatic Leukodystrophy (MLD) Lars G. Hanson1, Christine I. Dali2, Jens M. Fogh3 1Copenhagen University Hospital, Hvidovre, Denmark; 2Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark; 3Zymenex A/S, Roskilde, Denmark

Late infantile metachromatic leukodystrophy (MLD) is a fatal genetic disease leading to brain degeneration after the first year of life. Since treatments are being developed, it is important to be able to diagnose and monitor the disease in the early stages. Few spectroscopic studies of this rare condition exist and little is known about the progression and spatial distribution of metabolic changes. Four children in different stages of the disease were scanned with multi-slice echo planar spectroscopic imaging. An almost complete loss of white matter NAA signal was found in the later stages of the disease.

Poster Sessions

345

2067. Contrast-Enhanced Ex Vivo MR Reveals Inflammatory Zone in X-Linked Adrenoleukodystrohpy Megan L. Blackwell1, W C. Hubbard, M Selig, Bruce R. Rosen1, Ann B. Moser, Florian S. Eichler 1Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, USA

We demonstrate with luxol fast blue-enhanced MR microscopy a zone of macrophages and myelin debris at the leading edge of active demyelination. Both immunohistopathology and biochemistry helped to explain the distinct contrasts seen in LFB-enhanced MR images: inflammation on T2*-weighting and NAWM on T1-weighting. Thus, a single contrast agent is able to measure different biochemical parameters.Our findings support the conclusion that enhanced T2* susceptibility in ALD samples is in part due to compartmentalization of the LFB contrast agent. Our technique of contrast-enhanced ex vivo MR microscopy allows for the investigation of lipids and inflammation in the process of demyelination.

Developmental Brain Disorders Hall D Thursday 13:30-15:30

2068. Altered Diffusion Tensor MRI Indices of Frontal Cortical and Basal Ganglia in Children with Tourette Syndrome Assessed by Voxel-Based Analysis Study Malek Makki1, Michael Behen1, Elizabeth Primeau1, Benjamin Wilson1, Arpi Bhatt1, Harry Chugani1 1Wayne State University, Detroit, Michigan, USA

The neurobiological abnormalities underlying Tourette syndrome (TS) remain unknown despite various biochemical, neuroimaging, neurophysiological, and genetic studies that suggest a role of the basal ganglia and related thalamic and cortical regions. MRI studies of TS have reported volume reductions in the basal ganglia, frontal cortex, hippocampal gyrus, and white matter. We investigated interhemispheric brain asymmetry in children with TS using voxel-based analysis of diffusion tensor indices. Results show abnormal white matter integrity in regions comprising the fronto-striato-thalamic circuit in children with TS as compared to age-matched healthy controls, extending previous work that has shown this circuit as involved in TS.

2069. Abnormal White Matter Integrity of Striato-Thalamic Structures in Children with Tourette Syndrome Malek Makki1, 2, Mike Behen1, Arpi Bhatt1, Harry Chugani1 1Wayne State University, Detroit, USA

Despite a plethora of evidence suggesting that the fronto-striato-thalamic (FST) circuitry is abnormal in patients with Tourette Syndrome (TS), the structural integrity of white matter pathways has not yet been directly investigated. We used DT-MRI to test the hypothesis that TS may be associated with specific white matter abnormalities in the lentiform nuclei, thalamus, and caudate nucleus, and that individuals with TS will show decreased FA and increased ADC in fibers of FST as compared to healthy controls. We also examined whether abnormalities on DTI are associated with tic severity and obsessive-compulsive disorder and attention deficit hyperactivity disorder comorbidity.

2070. Application of Probabilistic Fiber Tracking for the Quantitative Assessment of the Connectivity Pattern Between Basal Ganglia and Frontal Cortex in Children with Tourette Syndrome Otto Muzik1, Malek Makki2, Darshan Pai2, Anita Dias3, Jing Hua2, Harry Chugani1 1Wayne State University, Detroit, Michigan, USA; 2Wayne State University, USA; 3CHM PET Center, Detroit, Michigan, USA

This paper describes a method for the quantitative assessment of fiber tract connectivity strength based on Bayesian probabilistic tractography. For each fiber path a normalized probability value is calculated which characterizes the probability of connection between two predefined cortical areas. We applied this method to DTI data derived from children with Tourette Syndrome (TS) and pediatric controls to evaluate the connectivity strength between subcortical and cortical regions. Our findings indicates an abnormal connectivity pattern between the head of caudate and frontal lobe regions in children with TS as compared to control children.

2071. Transverse Relaxation Rime Abnormalities of the Basal Ganglia in Tourette Syndrome Yann Gagnon1, Tim Devito1, Janet Hendry1, N Gelman1, N Rajakumar2, P Williamson2, R Nicolson2, Dick Drost1 1University of Western Ontario, Lawson Health Research Institute, London, Canada; 2University of Western Ontario, London, Canada

The transverse relaxation time (T2) is a quantitative parameter of magnetic resonance imaging which is indicative of the molecular environment in brain tissue. In this study, T2 times of lobar white matter were evaluated in a group of patients with autism. Images obtained at 3 Tesla using the GESFIDE technique were spatially normalized for statistical analysis. Patients in this study had an increase in left-sided white matter T2 as well as an increase in frontal and parietal white matter T2.

2072. Possible Sources of Functional Connectivity and Under-Connectivity in Adolescents with Autism Spectrum Disorders Tyler Bridgeland Jones1, Lauren Kenworthy, 12, Laura K. Case1, Shawn C. Milleville1, Peter Anthony Bandettini1, Alex Martin1, Rasmus Matthias Birn1 1National Institutes of Health, Bethesda, Maryland, USA; 2Childrens National Medical Center, Washington, District Of Columbia, USA

Adolescents with autism spectrum disorders (ASD) show decreased functional connectivity relative to typically developing individuals, supporting a model of underconnectivity in autism. Employing an overt fluency task to probe language and executive deficits typical of ASD, we aim to determine what factors contribute to the decreased correlations of spatially remote BOLD fMRI time series observed in ASD. By sequentially regressing out various factors, including differential task activation, trial-to-trial task response variability, and certain scanner artifacts, we conclude that the disruption in functional connectivity in ASD is at least partially due to differences in task-unrelated, or “spontaneous,” neuronal fluctuations.

Poster Sessions

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2073. A Study of Underconnectivity in Autism Using DTI: W-Matrix Tractography Jee Eun Lee1, David Hsu1, Andrew L. Alexander1, Mariana Lazar2, Erin D. Bigler3, Janet E. Lainhart3 1University of Wisconsin, Madison, Wisconsin, USA; 2New York University School of Medicine, New York, New York, USA; 3University of Utah, Salt Lake City, Utah, USA

A novel probabilistic method for diffusion tensor tractography (W-matrix tractography) was developed to study underconnectivity in autistic children. This algorithm incorporates measures of intravoxel and intervoxel structure and allows simultaneous multi-directional branching of white matter tracts. In preliminary testing comparing 43 autistic subjects with 34 matched controls, we find a strong tendency to segregate the autistic from the control populations, particularly in the younger subjects. With further tuning, W-matrix tractography may be useful in the early diagnosis of autism.

2074. White Matter Abnormalities in Youth with High Functioning Autism or Asperger Syndrome Using DTI Tractography and Voxelwise Analyses Manzar Ashtari1, Joel Bregman2, Shana Nichols2, Carolyn McIlree3, Linda Spritzer2, Andrew Adesman4, Melissa Narain5, Babak Ardekani6 1Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA; 2Fay J. Lindner Autism Center, Bethpage, New York, USA; 3University of Vermont, Burlington, USA; 4Schneider Children's Hospital, New Hyde Park, New York, USA; 5North Shore LIJ Health System, Glen Oaks, New York, USA; 6Nathan Kline Institute of Psychiatry, Orangeburg, New York, USA

We have applied diffusion tensor imaging to a whole-brain voxelwise analysis and tractography in a group of high-functioning youth with Autism Spectrum Disorder (ASD) and demographically matched controls. Results from tractography and voxelwise analysis showed increased FA in the posterior portion of the cingulate bundle (limbic system). Increased FA positively correlated with the social-emotional reciprocity and autistic mannerism of the ASD patients. Our data suggest that alterations in the limbic system secondary to suboptimal connectivity may lead to core impairments of social interaction and behavior associated with the autism phenotype.

2075. XXY (Klinefelter Syndrom): A FMRI Study of Prepubertal Boys Song Lai1, Fumiko Hoeft2, Jianrong Shi1, John Lackey1, Udomchai Techavipoo1, Adam Flanders1, David Roeltgen1, Allan L. Reiss2, Judith Ross1 1Thomas Jefferson University, Philadelphia, Pennsylvania, USA; 2Stanford University, Stanford, California , USA

A fMRI study was conducted to investigate the functional brain differences between prepubertal boys with KS (8-12 years) and age-matched control boys, and to examine function associated with androgen replacement in KS, so as to improve our understanding of cognitive deficits associated with KS and androgen deficiency. Relative to the age-matched control group, boys with KS showed aberrant activation patterns in a regional specific manner, depending on the cognitive operation (language and motor functions). Aberrant activation patterns showed ‘normalization (i.e., increase in activation)’ with androgen treatment.

2076. MRI of Prepubertal Boys with Klinefelter Syndrom: A Voxel-Based Morphometric Study Song Lai1, John Lackey1, Jianrong Shi1, Udomchai Techavipoo1, David Roeltgen1, Adam Flanders1, Fumiko Hoeft2, Allan L. Reiss2, Judith Ross1 1Thomas Jefferson University, Philadelphia, Pennsylvania, USA; 2Stanford University, Stanford, California , USA

A voxel-based morphometry study was conducted to investigate the structural brain differences between prepubertal boys with KS (8-12 years) and age-matched control boys in order to obtain insight of the underlying neuroanatomy of the KS cognitive phenotype. Boys with KS were found to have smaller brain volumes in regions related to cognitive functions of interest, including the left insula, ventrolateral prefrontal and temporal lobes, [language function], the bilateral anterior limb of the internal capsule (ALIC), globus pallidus, pre and post-central gyri and corpus callosum [for bimanual motor function], and the dorsolateral prefrontal and parietal lobes [working memory function.

2077. Deformation Based Morphometry of Brain Structure in Children with Difficulties in Mathematics Zhaoying Han1, 2, Lynn Fuchs1, Nikki Davis1, Christopher J. Cannistraci2, Adam W. Anderson2, John C. Gore2, Benoit M. Dawant1 1Vanderbilt University, Nashville, Tennessee, USA; 2Vanderbilt University Institute of Imaging Science, Nashville, Tennessee, USA

Anatomical differences between normal children (NC) and children with math difficulties (MD) are investigated with deformation based morphometry in a population comprised of 20 pairs of age and gender matched NC and MD children. High resolution MR images have been acquired and one population average has been computed using a non-rigid registration technique that produces dense deformation fields. Statistically significant differences in the deformation fields between the two populations were found in several areas that have been previously reported in functional studies as related to computation. These findings may explain the differences that have been observed in functional studies.

2078. Networks Utilized for Receptive Speech in Children with Right and Left Unilateral Sensorineural Hearing Loss Vincent Jerome Schmithorst1, Scott Kerry Holland1 1Children's Hospital Medical Center, Cincinnati, Ohio, USA

Children with severe-to-profound unilateral sensorineural hearing loss (USNHL) show deficits in higher-order auditory processing tasks. We investigate the task of receptive speech using functional MRI (fMRI) in children with right and left USNHL. The paradigm consisted of a “modified token” task. Subjects viewed an arrow moving to point to two shapes shown on a video screen. Subjects would respond if the speaker correctly described the motion of the arrow. Using group Independent Component Analysis (ICA), activation was shown in auditory processing and higher-order integrative regions. Results also indicate the preferential formation of auditory processing pathways ipsilateral to the hearing ear.

Poster Sessions

347

2079. Differences in White Matter Microstructure Between Children with Right and Left Unilateral Sensorineural Hearing Loss Vincent Jerome Schmithorst1, Scott Kerry Holland1 1Children's Hospital Medical Center, Cincinnati, Ohio, USA

Children with right unilateral sensorineural hearing loss (USNHL) show greater deficits in academic performance as compared to children with left USNHL. We investigate possible differences in white matter microstructure using diffusion tensor MRI (DTI). Children with right USNHL displayed greater fractional anisotropy (FA) in the genu and splenium of the corpus callosum, in frontal regions bilaterally, and in the left occipital lobe. Children with left USNHL displayed greater FA in temporo-parietal white matter in the left hemisphere. Results indicate preferential formation of inter-hemispheric pathways in children with right USNHL, and intra-hemispheric pathways in the left hemisphere in children with USNHL.

2080. Networks Used for Interpretation of Speech-In-Noise in Children with Unilateral Sensorineural Hearing Loss Vincent Jerome Schmithorst1, Scott Kerry Holland1 1Children's Hospital Medical Center, Cincinnati, Ohio, USA

We used functional MRI (fMRI) in conjunction with an audiological test performed in-scanner to investigate the source of auditory processing deficits in children with unilateral sensorineural hearing loss (USNHL). The task involves interpretation of speech-in-noise at varying levels of SNR. Using group Independent Component Analysis, networks were found related to task difficulty. Two attentionally-related components were found with activation in the frontal lobes. Two auditory-related components were also found, with activation in Wernicke’s area and its RH homolog, and activation in the left IFG (BA 45/47). Differences were also found between children with left and right USNHL.

2081. MRSI Detects Abnormalities in Normal-Appearing Frontal Lobe of Sturge-Weber Syndrome Patients Zhifeng Kou1, Meng Li1, Quan Jiang, Navid Seraji, Yang Xuan1, E Mark Haacke1, Harry T. Chugani, Csaba Juhasz, Jiani Hu1 1Wayne State University School of Medicine, Detroit, Michigan, USA

This study was to determine whether MRSI can improve detection of frontal lobe involvement in children with SWS. Among 16 children (age: 0.9 -10.4 years) with unilateral SWS, 8 children presented normal-appearing frontal lobes on conventional MRI, but 7 of them showed abnormal NAA and/or choline content in the frontal lobe of the affected hemisphere. Lower frontal lobe gray matter NAA was associated with earlier onset of seizures (r = 0.76; p = 0.04) and was an excellent predictor of motor function (r=-0.89, p<0.001). MRSI is more sensitive than conventional structural MRI for detection of frontal lobe involvement in SWS.

Drugs & the Developing Brain Hall D Monday 14:00-16:00

2082. Retinal Folding in the Term Rabbit Fetus - Developmental Abnormality or Fixation Artefact? Jane Halliday1, Julian French1, Marietta Scott1, Carsten Liess1, John Waterton1, Jane Stewart1 1AstraZeneca, Macclesfield, UK

Prior to administration of candidate medicines to women of child bearing potential, studies must be performed in pregnant animals to assess detrimental effects, such as malformations in embryofetal development. One such effect is “slight retinal folding” in the rabbit fetus. However, there is evidence that these folds may be caused by the traditional fixation process used in their examination. This study used MRI to assess rabbit retinal architecture both pre- and post-fixation. Whilst no retinal folding was detected in fresh specimens, folds were observed in 79% of fetuses post-fixation, inferring that retinal folds in the rabbit fetus are commonly artefactual.

2083. Effect of Fluoxetine on the Developing Brain Willy Gsell1, Estelle Jamard2, Francois Dauphin2, Michel Boulouard2, Jan Booij3, Amy Herlihy1, Sharon Williams1, Liesbeth Reneman3 1Hammersmith Hospital, Imperial College London, London, UK; 2University of Caen, Caen, France; 3Academic Medical Centre, Amsterdam, Netherlands

Fluoxetine (a serotonin reuptake inhibitor) has recently been approved for use in children and adolescents based on clinical trials performed in adults. However, there are concerns on the safety of fluoxetine when administered to children and adolescents. In this study we conducted a pre-clinical assessment to determine if the effects of the fluoxetine on the serotonin system are dependent on age, with respect to behaviour, density of serotonin transporters, and brain activation.

2084. Regional Brain Alterations in Children with Prenatal Alcohol Exposure: A Preliminary 3D Multi-Voxel 31P Spectroscopy Study at 4 Tesla Jeffrey A. Stanley1, Lisa M. Chiodo1, Dalal Khatib1, Rachel M. Dick1, Jalpa Patel1, Virginia Delaney-Black1, John H. Hannigan1 1Wayne State University School of Medicine, Detroit, Michigan, USA

Maternal alcohol consumption during pregnancy can harm the fetus, particularly the vulnerable central nervous system, making prenatal alcohol exposure (PAE) a leading cause of mental retardation and developmental disorders that include deficits in behavior and cognition (focused attention, arithmetic and working memory). Young children with and without PAE were assessed in 4 key regions using 3D multi-voxel 31P spectroscopy; a method sensitive to critical neurodevelopmental changes. Results show regional alterations in membrane phospholipid and high-energy phosphate metabolism. This suggests that maternal alcohol consumption during pregnancy may alter the time course of developmental changes from that seen in healthy children.

Poster Sessions

348

2085. Diffusion Tensor Tractography of Children with Fetal Alcohol Spectrum Disorder Catherine Lebel1, Carmen Rasmussen1, Katy Wyper1, Gail Andrew2, Jerome Yager1, Christian Beaulieu1 1University of Alberta, Edmonton, Canada; 2Glenrose Hospital, Edmonton, Canada

The purpose of this study was to determine the range of white matter abnormalities in children with fetal alcohol spectrum disorder (FASD) using diffusion tensor imaging (DTI). 24 children with FASD and 95 controls 5-13 years underwent DTI scans. Tractography delineated ten white matter tracts in each individual and measure fractional anisotropy and mean diffusivity. Significant diffusion abnormalities were observed in the splenium and genu of the corpus callosum, superior and inferior longitudinal fasciculi, inferior fronto-occipital fasciculus and cingulum. This supports previous findings of callosal abnormalities in FASD and demonstrates diffusion changes beyond the corpus callosum for the first time.

2086. Increased Creatine and Choline in the Brains of Children Exposed to Methamphetamine Prenatally Linda Chang1, Christine Cloak1, Bradley Tokeshi1, Brooke Hedemark1, Caroline Jiang1, Sarah Farhnam1, Lynne Smith2, Thomas Ernst1 1John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, USA; 2Harbor-UCLA Medical Center, Torrance, USA

Methamphetamine (METH) is a neurotoxic drug but its effects on brain development has not been well studied. Proton MRS was performed in seventy 3-4 year old children (33 METH-exposed prenatally and 37 un-exposed controls). Despite similar physical characteristics (including head circumference), global cognitive function (on Stanford-Binet), parental education, intelligence and mood, METH-exposed children had higher total creatine and choline concentration than un-exposed controls. Since total creatine and choline are higher in glia than neurons, these findings suggest abnormalities in glia development in these children with prenatal METH-exposure.

2087. MRI Evaluation of Morphological Changes Following Soman Exposure and Galantamine Treatment Jiachen Zhuo1, Jiazheng Wang2, Eduardo Helal-Neto3, Yasco Aracava3, George Makris1, Edna F.R. Pereira3, Rao P. Gullapalli1, Edson X. Albuquerque3 1University of Maryland School of Medicine, Baltimore, Maryland, USA; 2University of Maryland Baltimore County, Catonsville, Maryland, USA; 3University of Maryland Baltimore, Baltimore, Maryland, USA

The acute toxicity of nerve agents such as soman, sarin, tabun and VX has been associated with their potency to irreversibly inhibit acetylcholinesterase. In this study we examine the brain morphological changes following lethal exposure of soman in a guinea pig model. Further we assess the therapeutic effects of galantamine that blocks the effectiveness of the nerve agent. Our study reveals that both male and female guinea pigs undergo morphological changes immediately following soman exposure with large effects in the area of piriform, amygdalar and hippocampal areas with maximal damage at 24 hrs. Further, the effect of galantamine is immediate and is able to reverse this damage.

2088. Neuroprotective Effects of Alpha Lipoic Acid on Ecstasy-Exposed Zebra Finches: An in and ex Vivo Volumetric Analysis Parastou Foroutan1, 2, Crystal P. Perreault1, Susanne L.T. Cappendijk1, Samuel Colles Grant1, 2 1The Florida State University, Tallahassee, Florida, USA; 2FAMU-FSU College of Engineering, Tallahassee, Florida, USA

Adolescent Ecstasy use is known to induce cognitive impairment later in life. There are indications that this impairment is due to free radical formation. MR Microscopy techniques at 21.1 T were used to study the effects of the antioxidant alpha lipoic acid on Ecstasy-exposed zebra finches. Multi-slice 2D fast spin-echo images were acquired both in and ex vivo. 3D gradient-recalled echo images (40-micron isotropic resolution) also were obtained from ex vivo brain samples, and a volumetric analysis was performed on all datasets. These techniques contribute to a better understanding of the pharmacological effects of Ecstasy on neuroanatomical pathways of cognition.

2089. Identification of the Teratologic Effect of Prenatal Exposure of Cocaine Using Voxel Based Morphometry Eric Yann Pierre1, Sonia Minnes1, Olivier Salvado2, Lynn Singer1, Paul Weishampel1, Daniel T. Boll3, Jean Adelaide Tkach1 1Case Western Reserve University, Cleveland, USA; 2CSIRO - e-Health Research Centre, Brisbane, Australia; 3Duke University, Durham, USA

Cocaine crosses the placental and fetal brain barriers and directly affects neurodevelopment. Prenatal Cocaine Exposure (PCE) has been correlated with deficits in cognitive and language functioning, visual-spatial and arithmetic skills. However, little is known about specific teratologic effects of PCE. We used high spatial resolution MRI of exposed and non cocaine-exposed children and Voxel Based Morphometry to identify local tissue volume differences between the two populations. Local reductions in white and gray matter in regions of the visual association cortex involved in visual-spatial task performance were identified in PCE subjects.

The Aging Brain Hall D Tuesday 13:30-15:30

2090. Diffusion Tensor Imaging of Memory Decline Efrat Sasson1, Glen M. Doniger2, Ofer Pasternak1, Yaniv Assaf1, 3 1Tel Aviv University, Tel Aviv, Israel; 2NeuroTrax Corporation, Newark, New Jersey, USA; 3Tel Aviv Sourasky Medical Center, Tel Aviv, Israel

The brain imaging correlates of age-related memory decline were studied in 51 healthy subjects, age 25-82 years. Diffusion imaging parameters were correlated with memory performance in multiple regions. Since these changes stem in part derived from age-related changes we conducted partial correlation between MRI parameters and memory performance controlling for age. W found that changes in brain integrity correlated with memory decline adjusted for age are most prominent in gray matter, in language-related regions (the STG, IFG) and hippocampal complex. These results suggest that diffusion MRI, especially the ADC, can be a useful regional quantitative marker for memory decline.

Poster Sessions

349

2091. Orientation-Specific Degeneration of the Cerebral White Matter in Aging Brain Investigated by Geometric DTI Chun-Jung Juan1, Yi-Jui Liu2, Cheng-Yu Chen1, Tzung-Tzuo Tsai2, Ming-Chung Chou3, Tzu-Cheng Chao3, Chun-Jen Hsueh1, Chung-Ping Lo1, Hsiao-Wen Chung3, Te-Cheng Lai2, Guo-Shu Huang1 1Tri-Service General Hospital, Taipei, Taiwan; 2Feng Chia University, Taichung, Taiwan; 3National Taiwan University, Taipei, Taiwan

Geometric DTI is capable of characterizing the diffusion anisotropy into linear, planar and spherical orientations. It is therefore an excellent tool to investigate the degeneration of the cerebral white matter. In this study, geometric DTI will show you the orientation-specific degeneration of the corpus callosum and periventricular white matter of the aging brain before the occurrence of volume loss. Specifically, the genu of corpus callosum and the anterior periventricular white matter demonstrate greater decrease of planar diffusion anisotropy, while the posterior periventricular white matter harbors greater loss of linear diffusion anisotropy in the elders.

2092. Robust Segmentation of White Matter Tracts in the Aging Brain Mark E. Bastin1, Jonathan D. Clayden2, Jakub P. Piatkowski1, Amos J. Storkey1, Laura J. Brown1, Alasdair M J MacLullich1 1University of Edinburgh, Edinburgh, UK; 2University College London, London, UK

Understanding how aging affects brain structure is an important challenge for medical science. By allowing segmentation of tracts of interest from diffusion MRI data, tractography provides a promising tool for assessing white matter connectivity in old age. However, the output from tractography algorithms is strongly dependent on the subjective location of user-specified seed points, with the result that it can be difficult and time consuming to identify the same tract in different subjects. Here we evaluate the performance of a new method which reduces the sensitivity of tractography algorithms to seed point placement in the brains of normal aging subjects.

2093. Combined Multi-Spectral Quantitative MRI and Volumetry of the Brain with the Mixed-TSE Pulse Sequence and Bisecting Dual-Clustering Segmentation: A Technique for Studying Regional Ageing Patterns in Large Populations Naoko Saito1, Osamu Sakai1, Hernan Jara1 1Boston Medical Center, Boston University School of Medicine, Boston, Massachusetts, USA

Purpose: To develop a combined quantitative MR imaging (Q-MRI) and volumetry technique for assessing simultaneously the segmental brain ageing patterns and volumetric changes in children, adults, and elder humans. Methods: The whole-head datasets of 75 subjects (0.5-87 years) generated with the mixed-TSE pulse sequence were segmented with a dual-clustering segmentation technique generating 6 sub-segments (bilateral frontal, bilateral posterior and bilateral cerebellar segments). Results: The volumetric and relaxometric age changes in the cerebellar segments were more gradual than in the posterior and frontal segments. Conclusion: A combined Q-MRI-volumetry technique has been developed and tested with 75 subjects over the human lifespan.

2094. Cortical Thickness and Mobility Status in Healthy Aging Istvan Csapo1, Nicola Moscufo1, Leslie I. Wolfson2, Charles R. G. Guttmann1 1Brigham and Women's Hospital, Boston, Massachusetts, USA; 2University of Connecticut Health Center, Farmington, Connecticut, USA

We set out to investigate the link between cortical thickness and mobility status, white matter lesion load, and cognitive function in healthy elderly subjects. We found that regional cortical thickness correlates with mobility status. Thus, cortical thickness is a potentially important marker of mobility.

2095. Parallel Imaging in 3D MP-RAGE for Consistent Brain Volume Imaging Ek Tsoon Tan1, Clifton R. Haider1, Roger C. Grimm1, Jeffrey L. Gunter1, Chadwick P. Ward1, Denise A. Reyes1, Matthew A. Bernstein1, Clifford R. Jack1, Stephen J. Riederer1 1Mayo Clinic, Rochester, Minnesota, USA

Serial brain volume measurements can detect small changes in brain morphology that are attributable to pathologic progression of Alzheimer’s disease. However, the long scan time of pulse sequences used for this application, for example T1-weighted magnetization prepared rapid gradient echo (MP-RAGE), increases the probability of motion artifacts and decreases throughput. Parallel imaging can be applied to reduce scan time, but its inherent noise amplification might distort volume measurements. This work demonstrates that with acceleration factors up to six-fold, a recessed elliptical-centric view order results in more consistent volume measurements (<0.06% deviation) than a standard sequential view order (<0.5% deviation).

2096. Longitudinal Changes in Brain MRI and Cognition in Older Adults Ira Driscoll1, Yang An1, Michael Kraut2, Christos Davatzikos3, Susan Resnick1 1NIH, Baltimore, Maryland, USA; 2Johns Hopkins Medical Institutions, Baltimore, Maryland, USA; 3University of Pennsylvania, Philadelphia, Pennsylvania, USA

Application of serial imaging to study pathology demands understanding of structural changes with normal aging. The present study examines how volumetric MRI changes relate to cognitive decline in two groups of older adults (age 56-86) prospectively followed for up to 9 years: Normal (N = 131) and MCI (N = 18). Results suggest the lack of relationships between longitudinal structural brain changes and cognitive decline in clinically normal older adults, with significant relationships emerging only after MCI participants are added to the sample. One interpretation is that of a threshold beyond which structural changes result in negative functional cognitive outcomes.

2097. Brain Adaptations in Normal Aging Evaluated with Diffusion Tensor Imaging David C. Zhu1, Rose T. Zacks1, Jill M. Slade1 1Michigan State University, East Lansing, Michigan, USA

Older adults often have more difficulty with attention, executive function and memory compared to young adults. One possible cause of these difficulties is the alteration of neural fiber connectivity. Diffusion tensor imaging (DTI), through the derived parameters such as fractional anisotropy (FA), can directly assess the white matter fiber tracts which possibly degenerate with normal aging and more so with Alzheimer’s disease and mild cognitive impairment. Based on our recent DTI comparison study of normal young (age 20 ± 3 yrs) and older (age 74 ± 7 yrs) adult brains, we found FA changed at some specific anatomical regions with aging, suggesting an adaptation process.

Poster Sessions

350

2098. Quantitative Fiber Tracking in the Normal Aging Brain: Neuropsychological Correlates Natalie May Zahr1, Torsten Rohlfing2, Adolf Pfefferbaum2, Edith V. Sullivan1 1Stanford University, Stanford, California , USA; 2SRI International, Menlo Park, California , USA

Quantitative fiber tracking was used in young and elderly healthy men and women to examine age effects on white matter integrity and to examine functional correlates of these systems. Fiber tracking allowed quantification of FA and ADC for commissural (genu, splenium, anterior commissure) and bilateral association fibers (inferior longitudinal fasciculus, cingulate, uncinate and fornix). Age effects were prominent in anterior tracts, specifically, the uncinate, fornix and genu. Differential correlations between FA or ADC in fiber tracts and scores on working memory, motor or problem solving tasks provide convergent validity to the biological meaningfulness of the fiber tracked loci and metrics.

2099. Changes in CSF Pulsatile Flow Distributions with Age Mark E. Wagshul1, 2, Michael R. Egnor1, Susan Fiore1, Sarah L. Hochberg, Erin J. Kelly2, Candice J. Perkins1, Zengmin Yan1 1Stony Brook University, Stony Brook, New York, USA; 2Toshiba Medical Systems, Irvine, California , USA

Hyperdynamic pulsations of CSF flow in the cerebral aqueduct have been used as a marker of abnormal CSF dynamics in hydrocephalus. However, studies have shown that only severely elevated aqueductal stroke volume reliably predicts shunt success, while prediction is very variable in patients with normal to mildly-elevated levels. Furthermore, most prior literature has studied CSF flow in normal pressure hydrocephalus, while studies in pediatric hydrocephalus are very limited. In this study, we investigated the flow distribution between the ventricular and subarachnoid space in healthy controls and find marked changes in the distribution of CSF pulsations with age.

Diabetes Mellitus & the CNS Hall D Wednesday 13:30-15:30

2100. Cortical Thickness is Correlated with Tract-Specific Fractional Anisotropy in Type I Diabetes Daniel T. Franc1, Chris Kodl, Bryon Mueller, Ryan Muetzel, Elizabeth Seaquist, Kelvin O. Lim 1University of Minnesota, Minneapolis, USA

Tract-specific fractional anisotropy and regional cortical thickness measures were found to be reduced and correlated in patients with Type 1 diabetes.

2101. Non Invasive Detection of Glucose in the Brain of a Patient with Type 1 Diabetes by Means of 1H MRS at 3 Tesla Benjamin Schmitt1, Peter Bachert1 1German Cancer Research Center, Heidelberg, Germany

This study demonstrates a possibility to trace the energy metabolism in human brain tissue non invasively by means of proton NMR spectroscopy. We observed that it is possible to detect resolved glucose signals in the brain of a patient with type 1 diabetes on a commercial 3-T MR scanner. This technique does not require specific equipment and can therefore be easily included in clinical routine MR examinations at 3 Tesla.

2102. Glucose Transport and Neurochemical Profile in the Hippocampus of STZ-Induced Diabetic Rats Under Hyper- And Euglycaemia Studied by in Vivo 1H MRS at 9.4T João MN Duarte1, 2, Rui A. Carvalho1, Rodrigo A. Cunha1, Rolf Gruetter2 1Center for Neuroscience and Cell Biology, Coimbra, Portugal; 2Laboratory for functional and metabolic imaging, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland

Diabetes mellitus accentuates the age-dependent decline of cognitive function which is related to reduction of hippocampal volume, a brain structure involved in learning and memory processing. In the present study, we measured the neurochemical profile and the kinetics of glucose transport in the hippocampus of streptozotocin (STZ)-induced diabetic rats using non-invasive 1H NMR spectroscopy. Our results show that chronic hyperglycemia does not alter brain glucose transport/content and that glycemia restoration immediately normalizes most neurochemical alterations.

2103. Cerebral H-MRS Correlates of Painless Diabetic Neuropathy Rajiv Gandhi1, Dinesh Selvarajah1, Celia J. Emery1, Paul D. Griffiths2, Solomon Tesfaye1, Iain D. Wilkinson2 1Royal Hallamshire Hospital, Sheffield, UK; 2University of Sheffield, Sheffield, UK

Previous proton spectroscopy (H-MRS) studies have demonstrated abnormalities within the thalamus in patients with diabetic neuropathy (DN). It is unclear which parts of the brain’s sensory matrix are involved. A large 130 subject cohort was studied consisting subjects at different stages of DN plus controls without diabetes. Single voxel H-MRS was performed within the thalamus and somatosensory cortex at two TE’s. In subjects with painless DN, lower NAA/Cr was observed in the thalamus at long TE and lower NAA in the sensory cortex at short TE. There is spatial variation in H-MRS abnormalities in subjects with painless DN.

2104. Neurochemical Changes in Hippocampus of Developing Rats During Acute Hypoglycemia Ivan Tkac1, Kathleen Ennis1, Raghavendra Rao1 1University of Minnesota, Minneapolis, Minnesota, USA

In vivo 1H NMR spectroscopy at 9.4 T was used to investigate neurochemical changes in hippocampus of 14-day-old rat pups during insulin induced hypoglycemia. Significant changes from homeostasis were observed for Asp, Glc, Gln, Glu, Lac, Cr and PCr. Time courses of individual metabolites revealed different mechanisms supporting energy production. When endogenous Glc resources ware exhausted, amino acids Gln, Glu became primary sources to feed TCA cycle through different anaplerotic pathways.

Poster Sessions

351

Animal Models: Demyelination & Regeneration in Brain & Spine Hall D Thursday 13:30-15:30

2105. q-Space MRI and DTI of Excised Myelin Deficient Rat Brains Amnon Bar-Shir1, Ian D. Duncan2, Yoram Cohen1 1Tel-Aviv University, Tel-Aviv, Israel; 2University of Wisconsin, Madison, USA

High b-value q-space diffusion MRI was reported to be sensitive to myelination disorders. In the present study we used high b-value q-space diffusion MRI and conventional DTI to describe, for the first time, the diffusion characteristics of myelin-deficient (md) rat brains and their age-matched controls. This study clearly demonstrates that myelin affects, significantly, all three diffusion indices obtained from q-space DWI (i.e. displacement probability and kurtosis). This study also shows that FA, extracted from conventional DTI, blurs the differences between the two groups.

2106. Evaluation of Demyelination and Remyelination in Mouse Spinal Cord Using Multiexponential T2 and Magnetization Transfer Ratio Cheryl R. McCreary1, 2, Thorarin A. Bjarnason2, Viktor Skihar1, 2, J Ross Mitchell1, 2, V Wee Yong1, 2, Jeff F. Dunn1, 2 1Unversity of Calgary, Calgary, Canada; 2University of Calgary, Calgary, Canada

Identification of remyelination is important in the evaluation of potential treatments of demyelinating diseases like multiple sclerosis. Areas of demyelination with spontaneous remyelination have been observed in mice after a local injection of lysolecithin. The aim of this study was to determine if multi-exponential T2 analysis and magnetization transfer imaging, both indicative of myelin content, could detect changes in myelination, particularly remyelination, of the cervical spinal cord in mice treated with lysolecithin. We found that the short and intermediate T2 components showed significant changes over time and had began to return to control levels, while the MTR remained lower over the time course studied.

2107. Significant Brain Atrophy Precedes the Onset of Disability in a Murine Model of Multiple Sclerosis Istvan Pirko1, Yi Chen1, Jeremiah McDole1, Scott Dunn2, Diana Lindquist2, Aaron J. Johnson1 1University of Cincinnati, Cincinnati, Ohio, USA; 2Cincinnati Childrens Hospital Medical Center, Cincinnati, Ohio, USA

Brain atrophy is widely recognized in MS, but its pathomechanism remains unclear. Extensive central atrophy has not been reported in MS models. We demonstrate significant brain atrophy in TMEV infected SJL mice, an accepted MS model. Brain parenchymal fraction and ventricular volume analysis showed significant atrophy as early as 3 months, whereas motor deficits became significant at 4 months after induction. Atrophy progressed until 6 months, motor disability until 9 months after induction. NAA decrease accompanied the progressive atrophy. This model will enable us to investigate the pathomechanism of brain atrophy, and may lead to novel therapies addressing MS-related neurodegeneration.

2108. Mouse Brain Diffusion Tensor Magnetic Resonance Imaging (DT-MRI):Assessment of Demyelination and Recovery Laura Adela Harsan1, Dominik Paul1, Dominik von Elverfeldt1, Jerome Steibel2, Jürgen Hennig1, Said M. Ghandour2 1University Hospital Freiburg, Freiburg, Germany; 2Université Louis Pasteur, Strasbourg, France

In vivo DT-MRI was used to quantify the demyelination extent and the effects of a novel thyroid hormone (T3) based therapy, applied to induce recovery in the chronic demyelinated mouse brains. Long-term cuprizone treatment in mice resulted in severe and irreversible brain demyelination. The pathology caused changes of DT-MRI derived parameter values, including loss of anisotropy and increase of radial water diffusion values, D(radial). T3 hormone injections restored progressively a normal level of myelin. The microstructural reorganization of the white matter fiber tracts during the remyelination involved gradual recovery of the white matter anisotropy and restoration of normal D(radial) values.

2109. Radial Diffusivity Reveals a Role of Fibroblast Growth Factor 2: Inhibition of Remyelination After Chronic Demyelination Mingqiang Xie1, Regina C. Armstrong2, Sheng-Kwei Song3 1Washington University in St. Louis, St. Louis, Missouri, USA; 2Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA; 3Washington University, St. Louis, Missouri, USA

SynopsisMultiple sclerosis (MS) is an inflammatorily repeated or chronic demyelinating disease. Although populations of oligodendrocyte progenitors (OP) persist in the chronically demyelinating lesions, they typically fail to differentiate into myelinating oligodendrocytes. Previous study showed that absence of fibroblast growth factor 2 (FGF2) promotes OP differentiation into remyelinating oligodendrocytes and enhances remyelination. In this study, to monitor the spatial and temporal progression of spontaneous remyelination non-invasively, in vivo DTI biomarker of myelination, radial diffusivity was measured longitudinally in cuprizone treated live FGF2 -/- mice throughout the course of recovery period. The result showed that radial diffusivity in FGF2 -/- mice increased significantly following 12 weeks of cuprizone ingestion and returned to the control level at the end of the 12-week recovery period. Therefore, DTI detection was a sensitive measure for in vivo detection of the improved repair of chronic demyelination.

2110. Dynamics of USPIO Contrast in the Central Nervous System Unraveled in an Animal Model of Multiple Sclerosis Raoul Oude Engberink1, Elga de Vries2, Annette van der Toorn1, Susanne van der Pol2, Christien Dijkstra2, Erwin Blezer1 1University Medical Center Utrecht, Utrecht, Netherlands; 2VU Medical Center Amsterdam, Amsterdam, Netherlands

We studied the fate of USPIO longitudinally in a rat model of multiple sclerosis. Repetitive MRI was performed within a 6h period following a single intravenous USPIO injection both at onset as peak of the disease. Contrast effects in the brain are detected in 1h after injection and histological validation at 6h shows extra-cellular USPIO in the brain parenchyma. Signal changes in the brain are no longer detected 72h after injection and imaging of the cervical lymph nodes reveals USPIO accumulation over time. This study identifies USPIO as a marker for BBB damage in an early time frame.

Poster Sessions

352

2111. Evaluating Wallerian Degeneration in Visual Pathway of EAE Mice Shu-Wei Sun1, Hsiao-Fang Liang1, Anne H. Cross1, Sheng-Kwei Song1 1Washington University School of Medicine, St Louis, Missouri, USA

In this study, the feasibility of using axial and radial diffusivities in characterizing the primary and secondary axonal damage of EAE mice was evaluated. The decreased axial followed by increased radial in optic tract (OT) suggested that OT was likely damaged by the Wallerian degeneration. Since Wallerian degeneration can be delayed in Wlds mice, the delayed damage of OT in Wlds EAE, i.e., one month later than the damage to optic nerve (ON), supported that OT damage is a secondary degeneration originating from the initial ON damage.

2112. Axial Diffusivity in Optic Nerve Correlates Retinal Ganglia Cell Loss in EAE Mice Shu-Wei Sun1, Hsiao-Fang Liang1, Anne H. Cross1, Sheng-Kwei Song1 1Washington University School of Medicine, St Louis, Missouri, USA

Axonal and neuronal loss is the primary cause of the permanent disabilities in patients with MS. However, the relation between axonal and neuronal damage is still not clearly. Derived from DTI, axial and radial diffusivities have been used to detect axonal and myelin in optic nerve from EAE mice, an animal model for human MS. In this study, significant correlations between retinal ganglion cells (RGC, the cell body of optic nerve axons) loss and DTI abnormalities to optic nerve were demonstrated. This study suggested a causal relationship between the observed axonal and neuronal injuries in EAE mice.

2113. Focal Lesions Do Not Cause Neurological Impairment in EAE: Correlating Histology with in Vivo DTI Matthew D. Budde1, Sheng-Kwei Song1 1Washington University, Saint Louis, Missouri, USA

A decrease in axial diffusivity correlates with both axonal damage and hindlimb motor function in the spinal cord white matter of mice with experimental autoimmune encephalomyelitis (EAE), a model of Multiple Sclerosis. However, mice with EAE have varying degrees of long-term impairment as well as heterogeneous distributions of lesions. In the current study, both DTI parameter maps and histological sections stained for axonal damage were registered to a common space to address the relationship between localized axonal damage and neurological impairment in EAE. Both modalities demonstrate axonal damage is present throughout the white matter, not solely within lesions.

2114. High Resolution 1H NMR Spectroscopic Based Metabolomic Urine Analysis of EAE, an Experimental Murine Model of Multiple Sclerosis Harold G. Parkes1, Sarah Romero Shorter2, Po-Wah So3, David Baker4, Gavin Giovannoni4, Gareth Pryce4, Klaus Schmierer1 1University College London, London, UK; 2Birkbeck College, London, UK; 3Hammersmith Hospital, Imperial College London, London, UK; 4Queen Mary University of London, London, UK

EAE is an experimentally induced autoimmune disease in mice, exhibiting a similar disease progression as multiple sclerosis (MS) pathology in man including different pathology categorised as acute, chronic, remitting and relapse. 1H NMR spectroscopic analysis of urine showed significantly decreased excretion of certain metabolites, and specific to each pathology type. Thus, urine biomarkers may be generated by 1H spectroscopy to aid diagnosis and monitoring as well as pathological classification of clinical MS.

2115. Systemic Reactivation of a Focal MOG-EAE Lesion in Rat Brain Revealed by MRI and Immunohistochemistry sebastien Serres1, Yanyan Jiang1, Damian Tyler1, Daniel Anthony1, Nicola Sibson1 1University of Oxford, Oxford, UK

Multiple sclerosis (MS) is a neurodegenerative disease characterised by a chronic inflammatory disorder associated with demyelination. MS can display a relapsing-remitting form of disease in which bacterial infection may play a role. The aim was to discover whether a systemic infection can reactivate a quiescent MS-like lesion in the brain by using MRI and immunohistochemistry. Early increase of regional cerebral blood volume (rCBV) surrounding the lesion provides an insight into systemic reactivation of MS-like lesions and revealed the reactivation of a previously quiescent CNS lesion can be induced by a systemic inflammatory response in a clinically-relevent model of MS.

2116. Elucidating the Involvement of Spino-Olivocerebellar Pathways in Relapsing-Remitting EAE Using USPIO MRI Madhavi Pai1, 2, Peter F. Bousquest2, Annette J. Schwartz2, Bradford L. Mcrae2, Christine M. Nelson2, Vincent P. Hradil1, Bryan F. Cox1, Gerard B. Fox1, Chih-Liang Chin1 1Abbott Laboratories, Abbott Park, Illinois, USA; 2Abbott Bioresearch Center, Worcester, Illinois, USA

Experimental autoimmune encephalitis (EAE) is a widely-used animal model of multiple sclerosis. Recently, it has been demonstrated USPIO-enhanced MRI allows monitoring macrophage infiltration in vivo during the disease course of EAE. Here, we investigated the occurrence of lesions and its implications on observed neurological deficits in relapsing-remitting EAE. Results indicate USPIO-labeled lesions occurred in distinct CNS regions at various phases: brainstem (acute), no lesion (remission), and cerebellum and spinal cord (relapse), which reveal the involvement of spino-olivocerebellar pathways (cerebellar control of the limb posture and movement), in EAE. Our data provide important insights into further understanding of this disease model.

Diffusion Measures of Disease in MS Hall D Monday 14:00-16:00

2117. Diffusion Tensor Imaging in Pediatric Multiple Sclerosis: Studying Hemispheric White Matter Allison Bethune1, Brenda Banwell1, 2, Conrad Rockel1, John Sled3, Donald Mabbott1, 2 1The Hospital for Sick Children, Toronto, Canada; 2University of Toronto, Toronto, Canada; 3Toronto Centre for Phenogenomics, Toronto, Canada

The goal of this study was to explore hemispheric white matter (WM) changes in pediatric onset multiple sclerosis using DTI. T1, PD/T2 and DTI images for sixteen affected children and sixteen healthy controls were compared. Robust significant differences in fractional anisotropy and apparent diffusivity were observed in children with MS relative to healthy controls, and suggest compromised WM integrity may occur early in MS pathology. Further knowledge of pediatric onset MS is valuable in understanding the impact of WM damage in developing neural tissue.

Poster Sessions

353

2118. Diffusion Tensor Imaging in Multiple Sclerosis: Comparison of Radial and Axial Diffusivity Markers in Different Clinical Forms Salem Hannoun1, Françoise Durand Dubief, 12, Danielle Ibarrola3, Christian Confavreux2, Dominique Sappey-Marinier1, 3 1CREATIS-LRMN, UMR5220 CNRS & U630 INSERM & Université de Lyon, Villeurbanne, France; 2Hôpital Neurologique, Groupement Hospitalier Est, Bron, France; 3CERMEP-Imagerie du vivant, Groupement Hospitalier Est, Bron, France

This work concerned a longitudinal study of MS patients being followed by DTI to provide new markers of pathological processes and to evaluate the progression rate of the disease. Diffusion coefficients such as axial and radial diffusivities (ë1, ë2) were compared to FA and ADC. Preliminary results obtained in 35 patients showed significant increase of ADC, ë1 and ë2 values in different brain regions such as corpus callosum, grey nuclei, and white and grey matter. A larger change in ë2 suggested that radial diffusivity might be a better marker of myelin integrity whereas ë1 is more specific to axonal degeneration.

2119. Diffusion Tensor Eigenvalues Demonstrate Inherent Differences Between MS Lesion Subtypes Irene Vavasour1, Cornelia Laule1, Shannon Kolind1, David Li1, Anthony Traboulsee1, Alex MacKay1 1University of British Columbia, Vancouver, Canada

20 MS subjects were scanned with diffusion tensor imaging, and mean diffusivity, fractional anisotropy and the diffusion tensor eigenvalues were determined for enhancing lesions, isointense T1 lesions, hypointense T1 lesions and areas of contralateral NAWM. Diffusion metrics were significantly different between all lesion types and NAWM. The largest increase in eigenvalues was observed in hypointense T1 lesions (λ 1=36%, λ 2=74%, λ 3=131%), followed by enhancing lesions (λ 1=20%, λ 2=42%, λ 3=83%) and then isointense T1 lesions (λ 1=14%, λ 2=25%, λ 3=38%). The changes in mean diffusivity and especially FA were driven by the larger changes in smaller eigenvalues rather than the primary eigenvalue.

2120. A Diffusion Tensor Imaging Surrogate Marker of Brain Atrophy in Multiple Sclerosis Khader M. Hasan1, Christopher Halphen1, Arash Kamali1, Jerry S. Wolinsky1, Ponnada A. Narayana1 1University of Texas Health Science Center at Houston, Houston, USA

In this report we used a recently described and validated diffusion tensor imaging method to obtain the brain parenchymal fraction as a surrogate of atrophy on a cohort of relapsing and remitting (RRMS) patients and healthy adult controls. We demonstrate the utility of this approach by demonstrating strong correlation with the expanded disability status score (EDSS) and disease duration (DD).

2121. DTI Measures of Forniceal Injury Correlate with Episodic Memory Dysfunction in MS Micheal Phillips1, Kenneth Sakaie1, Stephen Rao1, Janice Zimbelman1, Lael Stone2, Erik Beall2, Katerine Koenig2, Ruthann Marrie3, Jian Lin2, Mark Lowe2 1Cleveland Clinic, Cleveland , USA; 2Cleveland Clinic, Cleveland, USA; 3University of Manitoba, Winnipeg, Canada

Cognitive deficits affect as many as 50% of patients with MS with 30-40% of patients having specific deficits in episodic memory. The hippocampus and fornix a clear role in episodic memory function. DTI measures forniceal injury were compared to neuropsychological tests of episodic memory function in MS patients. Axial diffusivity within the left hippocampus demonstrates an inverse correlation with verbal episodic memory dysfunction. Axial diffusivity within the right hippocampus demonstrates an inverse correlation with nonverbal memory dysfunction. Finding suggests that DTI of the fornix may be a potential future noninvasive biomarker of episodic memory dysfunction in MS.

2122. Diffusion Tensor Imaging of Multiple Sclerosis Cervical Spinal Cords T. H. Kim1, L. Zollinger1, X. F. Shi1, J. Anderson1, J. Rose1, Eun-Kee Jeong1 1University of Utah, Salt Lake City, Utah, USA

Multiple sclerosis (MS) is a white-matter disease with various pathologic stages such as demyelination, remyelination, inflammation, and axonal damage. These stages change the microscopic physical environments of the tissue water. Diffusion tensor MRI (DTI) is sensitive to the physical change in the tissue and may be used to detect early changes in the course of the disease. To investigate cervical spinal cord (CSC) damage, DTI has been employed using a 3D multi-shot diffusion-weighted EPI (ms-DWEPI), necessitating the development of a quadrature rf-coil and a controlled experimental environment. From DTI images, we have attempted to demonstrate cervical spinal cord damage in white matter in radial and longitudinal views of the cord.

2123. Temporal Changes of Fractional Anisotropy in DTI of the Corpus Callosum in Secondary Progressive Multiple Sclerosis: A Putative Marker of Accumulating Tissue Damage Weitian1, Jianhui Zhong1, Xiang Liu1, Praveen Rao2, Benjamin M. Segal2, Sven Ekholm1 1University of Rochester Medical Center, Rochester, New York, USA; 2University of Michigan, Ann Arbor, Michigan, USA

Secondary progressive multiple sclerosis (SPMS) is characterized by gradually accumulating neurological disability while regular MR imaging findings including enhanced lesions on the postcontrast images are not sensitive and specific in predicting the prognoses. Diffusion tensor imaging (DTI) was suggested to be sensitive in detecting brain tissue damage in MS. A longitudinal DTI study, including 11 patients who completed 6 bimonthly MR scans in the period of one year and 5 matched controls, was performed. Patients were divided into enhancing and non-enhancing group based on the presence of T1 enhancing lesions during the one-year study period. The Fractional anisotropy (FA) and Mean Diffusivity (MD) values in genu, body and splenium of corpus callosum (CC) were measured and compared between groups by repeated measures analysis of variance(ANOVA). Our results showed a significant difference in the time course change of FA between groups. Enhancing group also showed significantly progressive FA decrease in body and splenium CC over time. Our results suggest that the temporal decrease in FA in corpus callosum may be used as a putative marker to predict the severity and activity of SPMS.

Poster Sessions

354

2124. Geometric Distortion Correction on EPI: An Application for Diffusion Tensor Imaging of the Human Optic Nerve Udomchai Techavipoo1, 2, Annette Okai1, Thomas Leist1, Alex Dresner2, John Lackey1, Jianrong Shi1, Song Lai1 1Thomas Jefferson University, Philadelphia, Pennsylvania, USA; 2Philips Medical Systems, Netherlands

A reliable and practical method based on PLACE and SPHERE for correction of field-inhomogeneity distortion on EPI was applied to diffusion tensor imaging (DTI) of the human optic nerve. A conventional DTI sequence was tailored practically to overcome difficulties such as the optic-nerve size, the confounding signals from surroundings, the persistent motions, and the geometric distortion caused by susceptibility-induced magnetic field inhomogeneity from bone cavities and sinuses around the optic nerve. Values of DTI parameters before and after geometric distortion correction were compared to observe the integrity of the DTI sequence and the distortion correction.

2125. Visualisation and Quantitative Assessment of the NAWM in MS Patients by Using Q-Space Analysis of the Slow Diffusion Component at 3T Katrin Weier1, Eli Renate Gruener2, Jochen G. Hirsch1, Matthias Guenther3, Michael Amann1, Ludwig Kappos1, Wolfgang Steinbrich1, Ernst-Wilhelm Radue1, Achim Gass1 1University Hospital Basel, Basel, Switzerland; 2University of Bergen, Bergen, Norway; 3University Hospital Mannheim, Mannheim, Germany

Previous clinical studies have shown promising results of Q-space imaging of the slow diffusion component. It has been suggested, that the slow diffusion might predominantly represent intra-axonal/intra-cellular water diffusion. In order to investigate abnormality in the normal appearing white matter (NAWM) of MS patients we used an adapted protocol for clinical use of probability of zero displacement (PZD) on a 3T system. PZD maps were highly sensitive to detect reductions of the slow diffusion component in the NAWM of patients with different MS types. The resulting data allows a visual analysis to assess abnormality in the otherwise NAWM.

2126. Resting State Sensorimotor Functional Connectivity in Multiple Sclerosis Correlates with Transcallosal Motor Pathway Transverse Diffusivity Mark J. Lowe1, Erik B. Beall1, Ken E. Sakaie1, Katherine A. Koenig1, Lael Stone1, Ruth Ann Marrie2, Micheal D. Phillips1 1Cleveland Clinic, Cleveland, Ohio, USA; 2University of Manitoba, Winnipeg, Canada

We present initial results demonstrating, for the first time, a significant correlation between anatomic connectivity using DTI-based measures of white matter integrity and functional connectivity using spontaneous low frequency BOLD fluctuations. We report a signicant inverse correlation between transverse diffusivity of water averaged along the transcallosal motor pathway and functional connectivity between the primary sensorimotor regions in multiple sclerosis patients.

2127. Towards Assessing White Matter Integrity in Patients with Relapsing-Remitting Multiple Sclerosis Treated with Pioglitazone Dinesh K. Shukla1, Claudia K. Kaiser1, Demetrios D. Skias1, Glenn T. Stebbins2, Douglas L. Feinstein1 1University of Illinois at Chicago, Chicago, Illinois, USA; 2Rush University Medical Center, Chicago, Illinois, USA

Pioglitazone is an FDA-approved agonist, which has shown to reduce clinical and histological symptoms in MS animal model. We carried out a phase-I clinical trial of Pioglitazone in RRMS patients to monitor longitudinal changes in the characteristics of intrinsic brain tissue properties. DTI data were acquired and the results suggest that DTI parameters are sensitive markers to study the MS disease progression and may be predictive of pathological changes. Pioglitazone may improve anisotropy and reduce mean diffusivity at the site of degenerating tissue in RRMS patients. Further testing of this drug in larger cohort of MS patients is therefore warranted.

2128. Application of Locally Linear Embedding to Diffusion-Weighted MRI Data: Potential New Contrast Patterns in Multiple Sclerosis Peter Mannfolk1, Markus Nilsson1, Jimmy Lätt1, Elna-Marie Larsson1, Freddy Ståhlberg1, Ronnie Wirestam1, Sara Brockstedt1 1Lund University, Lund, Sweden

Several contrast parameters can be established by the use of diffusion weighted MRI, such as the apparent diffusion coefficient (ADC). These parameters are calculated from several samples of the diffusion signal attenuation. Although such contrast parameters can reveal differences between healthy and pathological tissue there exists a risk that different types of tissue are classified as similar even though they display differences in the signal versus b-curve. We investigate whether more information can be found in such data sets by use of Locally Linear Embedding. Analysis is performed on DW images acquired from one patient suffering from multiple sclerosis.

Multiple Sclerosis: MR Analysis Hall D Tuesday 13:30-15:30

2129. 7T MRI: A Powerful Vision of Microvascular Abnormalities in Multiple Sclerosis Yulin Ge1, Vahe Zohrabian1, Robert I. Grossman1 1New York University School of Medicine, New York City, New York, USA

Ultra-high-field (>3T) MRI techniques have the great potential to assess the venous vasculature by virtue of increased signal-to-noise (SNR) ratio and enhanced susceptibility effects. In this work, we describe 7T MRI findings on susceptibility-sensitive imaging in patients with MS, and relate our observations to early microvascular abnormalities as primary in vivo evidence of lesion development.

Poster Sessions

355

2130. Functional Correlates of Corpus Callosum Thickness in Multiple Sclerosis Christin Sander1, Mehul P. Sampat1, Annika M. Berger1, Peter Hildenbrand1, Rohit Bakshi1, Samia Khoury1, Howard Weiner1, Dominik S. Meier1, Charles R. G. Guttmann1 1Brigham and Womens Hospital, Boston, USA

A new automated method for generating an accurate width profile of the corpus callosum (CC) in mid-sagittal brain MR images was implemented. This approach utilizes Fourier descriptors to obtain a parameterized version of the boundary of the CC. The average CC width measurements were used to assess differences between clinical subtypes of Multiple Sclerosis and we observed that there was a significant difference between the Secondary Progressive patients and the Primary Progressive/Relapsing Remitting patients. The average CC width showed a negative correlation with clinical scores (EDSS, AI). A negative correlation was found with the sensory and cerebellar EDSS functional sub-scores.

2131. Different Patterns of Regional Subcortical and Cortical Atrophy in Patients with Multiple Sclerosis. a Case Control Study Deepa Preeti Ramasamy1, Michael G. Dwyer1, Jennifer L. Cox1, Milena Stosic1, David Fritz1, Robert Zivadinov1 1State University of New York at Buffalo, Buffalo, New York, USA

FreeSurfer, an automated method computed regional subcortical and cortical volumes in 21 normal controls (NC), 71 multiple sclerosis (MS) and 17 clinically isolated syndrome (CIS) patients. GLM analyses revealed significantly lower subcortical volumes for ventral diencephalon, thalamus, pallidum, hippocampus, putamen and increased volumes of entire ventricular system. Right posterior cingulate was the only cortical volume that showed difference between MS and NC groups. Patients with progressive MS had significant atrophy of caudate, hippocampus and amygdala compared to NC. Hence regional subcortical atrophy is more prominent than cortical atrophy in MS patients and also related to higher disability.

2132. Caudate Nuclei Degeneration in Multiple Sclerosis: A Multi-Modal Quantitative MRI Approach Khader M. Hasan1, Christopher Halphen1, Arash Kamali1, Jerry S. Wolinsky1, Ponnada A. Narayana1 1University of Texas Health Science Center at Houston, Houston, USA

We hypothesized that concomitant measurement of the intrinsic T2 relaxation time and DTI-derived metrics along with CNV would provide important clues to understanding the pathogenesis of MS. In this report we used DTI at 3T combined with T2 relaxation measurements along with caudate volumes on both age and gender-matched adult controls and relapsing-remitting (RRMS) patients to investigate the interplay between CNV, DTI metrics, T2, age, disease duration (DD), and disability (EDSS) in order to explore the microstructural contributors that lead to the normal-appearing caudate “macrostructural” atrophy.

2133. T2-Maps of Normal Appearing Brain Tissue Show Clusters of Voxels Correlating with Neuropsychological Test Results in MS Henrik Lund1, Agnete Jønsson2, Egill Rostrup3, Per S. Sørensen2 1Copenhagen University Hospital, Hvidovre, Denmark; 2Copenhagen University Hospital, Copenhagen, Denmark; 3Copenhagen University Hospital, Glostrup, Denmark

In 50 newly diagnosed patients with multiple sclerosis we address whether T2-changes in normal appearing brain tissue can add to the only moderate correlation between conventional magnetic resonance imaging and neuropsychological impairments as well as clinical measures. Outside focal lesions T2-maps showed clusters of voxel-wise correlation with impairments. As T2 lesion loads showed correlations with the same neuropsychological impairments but not with clinical measures, the latter might not capture the actual impairment of the patient. The study demonstrates its practical relevance and emphasizes a need for large-scale studies as results were obtained using conventional sequences from various sites and vendors.

2134. Phonological Fluency and Functional Connectivity in Multiple Sclerosis Katherine A. Koenig1, Erik Beall1, Michael Phillips1, Lael Stone1, Janice Zimbelman1, Stephen Rao1, Ruth Ann Marrie2, Mark J. Lowe1 1The Cleveland Clinic, Cleveland, Ohio, USA; 2University of Manitoba, Winnipeg, Canada

The nature of MS as a demyelinating disease leads us to hypothesize that patients will show reduced resting state functional connectivity as measured with low frequency BOLD fluctuation when compared to controls. Degeneration of specific white matter pathways is expected to correlate with performance on cognitive tasks dependent on those pathways. Sixteen individuals with multiple sclerosis and six controls were administered a test of phonological fluency, the Controlled Word Association Test. In MS patients, performance was significantly correlated with connectivity between posterior and anterior language regions. Functional connectivity may be a marker of pathway specific white matter disease in MS.

2135. Reduced Functional Adaptation to Working Memory Tasks with Increasing Complexity in Patients with Early Stages of Relapsing-Remitting Multiple Sclerosis Michael Amann1, 2, Jochen Gunther Hirsch2, Carla Raselli3, Iris Katharina Penner3, Ernst Wilhelm Radue2, Ludwig Kappos2, Achim Gass2 1Universitätsspital Basel, Basel, Switzerland; 2Universitätsspital Basel, Basel, Switzerland; 3Universität Basel, Basel, Switzerland

We investigated functional activation and connectivity in patients with early forms of relapsing-remitting multiple sclerosis (MS) on a 3T-scanner. So far, 6 MS patients and 6 controls performed an alertness task and three N-back tasks with increasing task difficulty. Significant differences between patients and controls were found in 2-back and 3-back, where patients had higher activation in medial frontal gyrus. In controls, the contrast between 3-back and 1-back showed a widely distributed change of activation, whereas in patients only sparse increase of signal was detected. The functional connectivity analysis revealed a slight trend of decreased connectivity in patients.

Poster Sessions

356

2136. Quantifying MRI with Increased Specificity for MS Pathology: A Longitudinal Method for Obtaining Whole-Brain Metrics of 3D Maps Derived from Non-Conventional MRI Jacqueline T. Chen1, D. Louis Collins1, Mishkin Derakhshan1, Douglas L. Arnold1 1Montreal Neurological Institute/McGill University, Montreal, Canada

Three-dimensional maps derived from non-conventional imaging have increased specificity to MS pathology, and whole-brain metrics based on these maps could clarify the evolution of pathology occurring concurrently with atrophy. However, cross-sectional analysis to calculate longitudinal change may be affected by inconsistent voxel populations due to atrophy of the brain between scans. We developed a longitudinal methodology, including non-brain-constrained-symmetric registration and joint-brain-mask calculation, to ensure evaluation of whole-brain metrics on the same voxels at both timepoints. We demonstrate that the approach is necessary and sufficiently accurate for use in clinical trials of MS therapies.

2137. Atrophied T2 Hyperintense Lesion Volume is Highly Predictive of Disability Progression. a 2-Year Longitudinal Study Using Voxel-Wise Dynamic Classification Robert Zivadinov1, 2, Niels Bergsland1, David Fritz1, Nima Hani1, Fernando Nussenbaum1, Bianca Weinstock-Guttman2, Jacqueline Durfee1, Nadir Abdelrahman1, Sara Hussein1, Marlieke De Bruijn1, Jennifer L. Cox1, Michael G. Dwyer1 1State University of New York, Buffalo, New York, USA; 2The Jacobs Neurological Institute, Buffalo, New York, USA

A fully automated voxel-wise based dynamic method of T2-lesion volume (LVs) classification into new, stable, resolving and atrophied T2-LVs was developed and validated in 208 multiple sclerosis (MS) patients. Over 2 years, 59.3% of the total T2-LV was stable, 50.8% was new, 38.4% resolved and 1.7% atrophied into the CSF. Atrophied T2-LV showed the strongest relationship with disability development (r=0.44, p=0.0008) and evolution of all non-conventional MRI measures (all p<0.0001). Robust correlation of atrophied T2-LV with all clinical and MRI parameters suggests that shrinkage of lesions into the CSF is an important mechanism of disease progression in MS.

2138. Evolution of Quantitative Magnetization Transfer Imaging Parameters in Acute Lesions of Multiple Sclerosis Ives R. Levesque1, Paul S. Giacomini1, Sridar Narayanan1, Luciana T. Ribeiro1, John G. Sled2, Doug L. Arnold1, G Bruce Pike1 1McGill University, Montreal, Canada; 2Hospital for Sick Children, Toronto, Canada

This study reports quantitative magnetization transfer imaging (QMTI) parameters longitudinally in acute, gadolinium-enhancing lesions of five multiple sclerosis patients. Significant changes were observed in most of the QMTI parameters when compared to contralateral regions of normal appearing white matter. The differences were greatest at the time of enhancement, and followed a pattern of partial recovery that stabilized over two to three months. The degree to which the recovery reflects remyelination and resolution of edema is not definitive, but the pattern suggests relatively quick resolution of inflammation and slower process of remyelination.

2139. Grey Matter Magnetization Transfer Ratio Reflects Clinical Evolution in Primary Progressive Multiple Sclerosis: A Longitudinal Study Zhaleh Khaleeli1, Daniel Altmann1, 2, Mara Cercignani3, Olga Ciccarelli1, David Miller4, Alan Thompson1 1Institute of Neurology, London, UK; 2London School of Hygiene and Tropical Medicine , London, UK; 3Institute of Neurology, UK; 4Institute of Neurology , London, UK

Surrogate and prognostic markers are needed for clinical trials in primary progressive MS (PPMS). We examined MTR Histograms in PPMS over three years. We used piecewise mixed effect linear regression models to calculate the relationship between rate of change in MTR and clinical variables, and multiple proportional odds ordinal logistic regression models to find whether baseline MTR predicted clinical progression. More rapid decline in grey matter (GM) mean MTR was associated with more rapid clinical progression, and GM peak height MTR independently predicted clinical outcome at three years. GM MTR is a useful surrogate marker for clinical progression in PPMS.

2140. Longitudinal Cortical Atrophy Detection Using Geometric Active Contours: A Validation Study Kunio Nakamura1, Richard Rudick, Elizabeth Fisher1 1Cleveland Clinic Foundation, Cleveland, Ohio, USA

Gray matter (GM) involvement in multiple sclerosis is well established, but difficult to measure. GM atrophy measurement using cross-sectional segmentation is too imprecise for short-term studies. We developed a new cortical longitudinal atrophy detection algorithm (CLADA) that creates a subject specific deformable model using data from all available time-points. CLADA was evaluated for accuracy using comparisons to manual segmentation and for reproducibility using a scan-rescan test. The results showed excellent correlations (>0.9) and low coefficient of variation (0.42%), indicating CLADA is suitable for measurement of cortical GM atrophy in longitudinal studies of MS patients.

2141. Assessment of Demyelination and Remyelination in Acute MS Lesions: Magnetization Transfer Ratio Imaging Versus Quantitative Magnetization Transfer Imaging Paul Steven Giacomini1, Ives R. Levesque1, Luciana T. Ribeiro1, Sridar Narayanan1, G Bruce Pike1, Douglas L. Arnold1 1McGill University, Montreal, Canada

We used quantitative magnetization transfer imaging (qMTI) to validate magnetization transfer ratio (MTR) change as a marker of myelin content change in acute gadolinium-enhancing lesion voxels, where inflammation and edema could potentially confound MTR changes. We longitudinally studied six patients with acute enhancing lesions and found that, despite some attenuation of the MTR decrease at the time of enhancement, the MTR and the restricted pool proton density (a qMTI marker of myelin change that is less susceptible to changes in water content) were strongly correlated as the enhancing lesion voxels evolved.

Poster Sessions

357

2142. New Approaches for MS Lesion Characterization with Ultrahigh Field MRI: Comparison of T2*/Phase Susceptibility Weighted Images with T2- And Inversion Recovery Fast Spin Echo Sequences Jaimin Shah1, Kottil Rammohan1, Michael Racke1, Kathrine Hawker1, Amir Abduljalil1, Steffen Sammet1, Michael V. Knopp1, Petra Schmalbrock1 1Ohio State University, Columbus, USA

Ten MS patients were scanned at 7T with susceptibility weighted imaging (SWI) to generate proton density/T2*-weighted magnitude and phase images. T2-weighted and white matter attenuated IR-TSE images were acquired. Of the lesions seen on T2 and IR-TSE, 85-100% were seen on SWI-magnitude images. Conversely, only 34-74% of the lesions seen on the SWI- magnitude images were seen on the SWI-phase images. Lesions seen only on magnitude images likely reflect increased free water due to demyelination, whereas lesions seen on the SWI-phases have a paramagnetic component either due to increased tissue iron, or due to increased deoxyhemoglobin indication increased vasculature.

2143. R2, Field Dependent R2 Increase (FDRI) and Refocusing Pulse Time Dependent R2 Increase τ DRI) in Multiple Sclerosis Compared to Healthy Controls Jaimin Shah1, Georgeta Mihai1, Kottil Rammohan1, Michael K. Racke1, Francisco Aguila1, Xiangyu Yang1, Steffen Sammet1, Michael V. Knopp1, Petra Schmalbrock1 1Ohio State University, Columbus, USA

R2 relaxation rates were measured at 3T and 7T, with long and short refocusing pulse times, in Multiple Sclerosis and healthy controls. R2 measurements for MS patients were lower compared to controls, seemingly because demyelination increases free water content in MS. R2 differences at 7T versus 3T (field dependent R2 increase, FDRI) were larger in MS patients, reflecting iron. Conversely, refocusing pulse time dependent R2 increases τ DRI) were larger in healthy subjects than in MS. This may be due to increased diffusion in demyelinated MS brain dominating τ DRI.

2144. Optimizaion of Imaging Parameters of 3D-FSE-XETA FLAIR for Detection of Multiple Sclerosis (MS) Lesions on a 3T Scanner Yi Tang1, J.-y Gerorge Chiou1, Dominik S. Meier1, Yang Duan1, 2, Arnaud Charil1, Janice Fairhurst1, Hammond G. Reynolds3, Gilbert J. Beers1, Amir Arsalan Zamani1, Charles R.G Guttmann1 1Brigham and Women’s Hospital Harvard Medical Schoo, Boston, Massachusetts, USA; 2The First Hospital China Medical School,, Shenyang, People's Republic of China; 3GE Medical Systems , Boston, Massachusetts, USA

The 3D-FSE-XETA (eXtended Echo Train Acquisition) FLAIR sequence was tested on a 3T MR scanner (GE Signa) with the following parameters: automatically calculated TI for nulling CSF signal; TR=6200 msec; TEs, ranging from 130 (GE prototype), 155, 200, 220 msec for improving T2 contrast between lesions and normal brain tissues. 3D-FSE-XETA FLAIR is a promising sequence for MS imaging on 3T scanners. The MS lesions can be identified with higher confidence when the parameters of TE and voxel size are optimized to increase lesion contrast and conspicuity.

2145. Absolute Quantification of T1, T2, PD and B1 on Patients with Multiple Sclerosis, Covering the Brain in 5 Minutes J. West1, 2, J.B.M Warntjes2, 3, O. Dahlqvist Leinhard1, 2, P. Lundberg1, 2 1Division of Radiation Physics and Radiology, Linköping, Sweden; 2Center for Medical Image Science and Visualization, Linköping, Sweden; 3Division of Clinical Physiology, Linköping, Sweden

There is only a weak correspondence between clinical symptoms of Multiple Sclerosis and Magnetic Resonance findings. In order to improve the assessment of structural changes in the brain using MRI a method was developed that allows for simultaneous quantification of T1 and T2 relaxation, proton density and the B1 field that covers the complete brain with high resolution in a scan time of only 5 minutes. Gradual changes of white matter into MS lesions can be clearly be distinguished. Partial volume of MS lesions into white matter can be quantified resulting in the absolute determination of pure lesion volume in the brain.

Epilepsy Hall D Wednesday 13:30-15:30

2146. SPHARM Detects Hippocampal Subfield Pathology in Temporal Lobe Epilepsy Hosung Kim1, Mark Niethammer2, Boris C. Bernhardt1, Sylvain Bouix2, Neda Bernasconi1, Andrea Bernasconi1 1Montreal Neurological Institute and Hospital, Montreal, Canada; 2Harvard Medical School, Boston, Massachusetts, USA

Our purpose was to detect volume changes in the hippocampal subfields of patients with pharmacoresistant temporal lobe epilepsy (TLE) using SPHARM, a surface-based shape analysis method. We studied 95 TLE patients with unilateral hippocampal atrophy on MR volumetry and 46 controls. SPHARM applied to manual hippocampal labels measured a distance at each vertex between groups. In more than 40% of patients, we found a bilateral CA1 inward deformation more marked ipsilateral to the focus. These changes were negatively correlated with disease duration. Predominant CA1 atrophy with relative sparing of other subfields is in agreement with histopathological hippocampal sclerosis.

2147. Abnormal Gyrification of the Cerebral Cortex in Mesial Temporal Lobe Epilepsy Cathy Scanlon1, Lisa Ronan1, Colin Doherty2, Norman Delanty1, Mary Fitzsimons1 1Beaumont Hospital, Dublin 9, Ireland; 2St. James's Hospital, Dublin 6, Ireland

The aim of this project is to identify abnormalities of cerebral cortical gyrification in mesial temporal lobe epilepsy using advanced quantitative magnetic resonance image-based techniques. Our results demonstrate a statistically significant reduction in temporal lobe gyrification. The identification of brain morphological abnormalities in TLE may help to further elucidate the pathogenesis of this disease.

Poster Sessions

358

2148. Simultaneous FMRI and Electrophysiology During Intracerebral Stimulation of Partial Seizures in Rats Dario J. Englot1, Asht M. Mishra1, Michael Purcaro1, Peter Herman1, Fahmeed Hyder1, Hal Blumenfeld1 1Yale University School of Medicine, New Haven, Connecticut, USA

fMRI could be a useful tool for studying partial limbic seizures because of its success with other seizure models. However given patient movement during temporal lobe seizures, human fMRI recordings in temporal lobe epilepsy are technically difficult. Therefore, animal models would be extremely valuable. Here we describe an anesthetized rat model where electrical stimulation of the hippocampus induces limbic seizures which mimic complex-partial temporal lobe seizures in humans. We achieved reliable EEG and fMRI data, simultaneously acquired, during intracerebral stimulation. The network of increased BOLD signal changes occurred within expected areas based on separate neurophysiologic studies.

2149. Decrypting Cryptogenic Partial Epilepsy Using White Matter Fractional Anisotropy Analysis Simon Sean Keller1, Thomas Duning2, Christoph Kellinghaus2, Siawoosh Mohammadi2, Hagen Schiffbauer2, E Bernd Ringelstein2, Stefan Knecht2, Michael Deppe2 1University of Liverpool, Liverpool, UK; 2University of Muenster, Germany

In patients with electroclinical evidence of cryptogenic partial epilepsy (PE) without brain abnormalities on conventional MRI, we show reduced fractional anisotropy (FA) in multi-lobar regions symmetrically, and asymmetrical temporal lobe FA reduction consistent with the side of the epileptogenic focus. We suggest that diffusion tensor imaging analysis of FA may represent an effective method for lateralising a neuroanatomical abnormality underlying the epileptogenic zone during pre-surgical evaluation of PE.

2150. Multimodal MRI Reveals Secondarily Generalized Seizure Related Microstructural Brain Tissue Abnormalities at 1.5 T Jacobus F.A. Jansen1, M Eline Kooi1, Marielle C.G. Vlooswijk1, H J.M. Majoie1, Rianne P. Reijs1, Paul A.M. Hofman1, Klaas Nicolay2, Marc C.T.F.M. de Krom1, Albert P. Aldenkamp1, Walter H. Backes1 1Maastricht University Hospital, Maastricht, Netherlands; 2Eindhoven University of Technology, Eindhoven, Netherlands

Patients who have suffered a high number of secondarily generalized tonic-clonic seizures (SGTCS) frequently show cognitive comorbidity. We have investigated whether a high number of SGTCS accumulated over life is associated with microstructural and metabolic changes in brain tissue. Sixteen patients with localization-related epilepsy with SGTCS underwent multimodal quantitative MRI (1.5 T), comprising T2 relaxometry, DWI, and MRSI. SGTCS are associated with significant changes in microstructural brain tissue characteristics within the frontal lobes, but not in the temporal lobes. These frontal changes possibly explain the cognitive problems which are often observed in patients with many SGTCS. This knowledge may help in the development of treatment aimed at preventing decline in cognitive abilities.

2151. Voxel Based Morphometry of 3D FLAIR Imaging in Cryptogenic Intractable Focal Epilepsy Kate J. Riney1, 2, Kling C. Chong2, J Helen Cross1, 2, Chris A. Clark1 1University College London Institute of Child Health, London, UK; 2Great Ormond Street Hospital for Children NHS Trust, London, UK

Fluid-attenuated inversion-recovery (FLAIR) magnetic resonance imaging has improved the detection of focal cortical dysplasia (FCD) which can underlie intractable focal epilepsy (IFE). Recently methods have been developed to allow the acquisition of 3D FLAIR volumes. Voxel based morphometry (VBM) is an objective method of assessing 3D volumetric imaging, performing a voxel-wise comparison between an individual brain and a control group. In this study we report on a method for performing VBM of 3D FLAIR and validate this technique through reliably detecting the FCD in 7/8 children with IFE and visible FCD. In addition we report that VBM of 3D FLAIR detected abnormality in 4/14 children with cryptogenic IFE and in 2/4 the VBM abnormality was subsequently found to represent FCD not seen on previous image reporting. For the children in whom FCD has been detected with VBM of 3D FLAIR, epilepsy surgery may now become a possible treatment option.

2152. Combined EEG, FMRI, and Cognitive Testing in Childhood Absence Epilepsy Rachel Berman1, Michiro Negishi1, Marisa Spann1, Mi Hae Chung1, Michael Joseph Purcaro1, Edward J. Novotny1, R.Todd Constable1, Hal Blumenfeld1 1Yale University, New Haven, Connecticut, USA

Patients with childhood absence epilepsy (CAE) have repeated 5-10 s episodes of unresponsiveness, associated with a “spike-wave” discharge on electroencephalography. The fundamental mechanisms of altered brain function and impaired attention in CAE are not known. Our central hypothesis is that SWD cause dysfunction in specific networks important for attention, including the medial frontal cortex and thalamus. If confirmed, this may lead to regional therapies targeted at improving impaired attention in patients with CAE. We will, therefore, map abnormal function in CAE, between and during seizures, using simultaneous EEG-fMRI and test attentional vigilance with the continuous performance task (CPT).

2153. Short and Long Term MRI Abnormalities After Experimental Febrile Seizures Jacobus F.A. Jansen1, Evi M.P. Lemmens1, Gustav J. Strijkers2, Jeanine J. Prompers2, M Eline Kooi1, Klaas Nicolay2, Govert Hoogland1, Walter H. Backes1 1Maastricht University Hospital, Maastricht, Netherlands; 2Eindhoven University of Technology, Eindhoven, Netherlands

Experimental febrile seizures (FS) are known to increase the risk for eventual temporal lobe epilepsy. Quantitative multimodal MRI may provide early markers of microstructural and metabolic changes. FS were induced in 9-day old rats by hyperthermia exposure. Hippocampal volumetry and 1H-MRS, and cerebral T2 relaxometry and DTI was applied in FS rats and controls (24h and 8w later). At 9 weeks histological analysis was performed. Hippocampal T2 elevations at 24 hours appeared to be transient. DTI abnormalities detected in the amygdala at 24 hours persisted up to 8 weeks. Hippocampal volume was not affected. Histological analysis showed increased hippocampal (fiber density and anisotropy) and amygdalar changes. Quantitative MRI is able to detect both transient and long-term FS induced abnormalities in the limbic system that reflect microstructural alterations. These long-term findings support the concept that early-life FS are related to epilepsy.

Poster Sessions

359

2154. MRI Measurements After Status Epilepticus Can Be Used as an Early Biomarker for the Hippocampal Injury in the Rat Lithium-Pilocarpine Model ManKin Choy1, Rodney C. Scott1, David L. Thomas2, Ken K. Cheung2, David G. Gadian1, Mark F. Lythgoe, 12 1UCL-Institute of Child Health, London, UK; 2UCL, London, UK

Status epilepticus (SE) can cause hippocampal injury, with subsequent cognitive decline and development of temporal lobe epilepsy (TLE). We investigated these events using CBF, ADC and T2 in the lithium-pilocarpine rat model of SE and identified time-dependent MR changes that peaked on day 2. A strong relationship was identified between these peak changes and subsequent hippocampal volumes measured on day 21, which suggests that MRI measurements on day 2 after SE can be used as an early biomarker for the associated progressive hippocampal injury.

2155. Perfusion MRI Changes During Status Epilepticus in the Rat Pilocarpine Model ManKin Choy1, Rodney C. Scott1, David L. Thomas2, Jack A. Wells2, Edward Proctor1, David G. Gadian1, Mark F. Lythgoe, 12 1UCL-Institute of Child Health, London, UK; 2UCL, London, UK

There is a known relationship between convulsive status epilepticus (SE) and hippocampal injury, although the reasons for particular hippocampal injury remain uncertain. Potential mechanisms of injury include excitotoxicity and ischaemia. During the early phase of seizures, CBF increases in the cortex to meet energy demand, but it remains uncertain whether similar changes occur in the hippocampus. We have used perfusion MRI to investigate SE and have identified a limited CBF response in the hippocampus during pilocarpine-induced SE, which may in part account for the selective vulnerability.

2156. A New Method to Quantify Language Lateralization in FMRI Using Whole Brain Analysis Stephen E. Jones1, Shamseldeen Younes Mahmoud1, Mark J. Lowe1, Michael D. Phillips1 1CCF, Cleveland, Ohio, USA

We present a new method to quantify language lateralization from fMRI studies, which uses a whole brain histogram approach. Advantages include no need to a priori threshold, and higher sensitivity for small activations.

2157. TLE is Associated with Reduced Folding of the Temporal Neocortex Boris Christian Bernhardt1, Hosung Kim1, Neda Bernasconi1, Andrea Bernasconi1 1Montreal Neurological Institute and Hospital, Montreal, Canada

Our purpose was to quantify the neocortical gyrification in temporal lobe epilepsy (TLE), and to investigate its relationship to underlying morphological parameters using MRI. We extracted skeletons of the temporal neocortex of 92 TLE patients and 33 controls. On the skeletons, we measured the fractal dimension (FD), total sulcal sulcal length (TL), and average sulcal depth. In the lateral temporal cortex, we observed a bilateral decrease of FD and TL in TLE with a left-sided seizure focus. FD was positively correlated to TL, but not to sulcal depth. A ”simplified” lateral temporal lobe may indicate a neurodevelopmental disruption in TLE.

Mixed Brain Pathology Hall D Thursday 13:30-15:30

2158. First Evidence That Frontal Lobe Choline-Containing Compounds Further Decrease and NAA Increases During Early Abstinence in Alcohol Dependent Patients Gabriele Ende1, Nuran Tunc-Skarka1, Derik Hermann1, Mareen Hoerst1, Sigi Walter1, Matthias Ruf1, Katharina Kraus1, Sabine Klein1, Karl Mann1 1Central Institute of Mental Health, Mannheim, Germany

Previous MRS studies have left the question how and when the Cho increase with alcohol consumption reverts into decreased Cho in abstinent alcoholics. We studied alcohol dependent patients early during detoxification and 2 weeks into abstinence, heavy alcohol drinkers and light to medium social drinkers at 3T. We see first evidence for our hypothesis that alcohol triggers non-linear dynamic changes of the Cho concentration: Cho initially increases with alcohol consumption but starts to decrease when alcohol abuse starts and significantly decreases during alcohol early abstinence. In contrast NAA shows a trend towards recovery within the first 2 weeks of abstinence.

2159. Positive Correlation Between Absolute Choline Concentration with Alcohol Consumption in the Frontal White Matter of Social Drinkers Nuran Tunc-Skarka1, Mareen Hoerst1, Tim Wokrina1, 2, Gabriele Ende1 1Central Institute of Mental Health, Mannheim, Germany; 2now at Bruker BioSpin MRI GmbH, Ettlingen, Germany

It has been previously shown at a 1.5T scanner that in alcohol dependent patients after detoxification the Cho and its ratio to Cr is below-normal and increases with duration of abstinence. Now we aimed to replicate the correlation at a 3T scanner and also wanted to examine whether the correlation is caused by Cho concentration change or if it might be an effect of altered relaxation. We could corroborate a significant positive correlation between the Cho concentration in the FWM and alcohol consumption of the last two weeks (R = 0.823, p = 0.000).

2160. Longitudinal Changes of Cerebral Gray Matter Perfusion in Smoking and Non-Smoking Abstinent Alcoholics Anderson Mon1, Timothy Craig Durazzo1, Stefan Gazdzinski2, Dieter Johannes Meyerhoff1 1UCSF, San Francisco, California , USA; 2CIND, San Francisco, California , USA

Synopsis: We used longitudinal perfusion MRI analysis to study cerebral gray matter perfusion changes in short-term abstinent alcoholics. The subjects were divided into cigarette-smoking alcoholics and non-smoking alcoholics. We observed that cerebral perfusion significantly increased in the non-smoking alcoholics over the first month of abstinence from alcohol but did not change in the smoking alcoholics. This suggests that cigarette smoking modulates cerebral perfusion recovery.

Poster Sessions

360

2161. Diffusion Tensor Imaging of White Matter Abnormalities in Patients with Writer’s Cramp Christine Delmaire1, Marie Vidailhet2, Maxime Descoteaux3, Demian Wassermann3, Frederic Bourdain4, Christophe Lenglet3, Sophie Sangla2, Axel Terrier5, Rachid Deriche3, Stéphane Lehéricy6 1Roger Salengro Hospital, Lille, France; 2Pitie Salpetriere Hospital, Paris, France; 3INRIA, Sophia Antipolis, France; 4Foch Hospital, France; 5Saint Antoine Hospital, Paris, France; 6University Pierre and Marie Curie-Paris 6, Paris, France

In this study, we investigated white matter abnormalities using diffusion tensor imaging (DTI) in 26 patients with focal hand dystonia compared with 26 healthy volunteers. SPM analysis showed that patients had increased FA values bilaterally in the area of the posterior limb of the internal capsule. FA abnormalities were located along the fiber tracts connected to the primary motor and sensory areas. These FA abnormalities were likely to reflect a specific disturbance of the white matter pathways that carry afferents and efferents to the primary sensory motor cortex.

2162. Autonomic Dysfunction in Primary Biliary Cirrhosis (PBC) is Associated with Structural Brain Abnormalities, Particularly in the Globus Pallidus Kieren Grant Hollingsworth1, Ahmed M. El-Sharkawy1, Zia U. Khan1, Andrew M. Blamire1, Roy Taylor1, David E. Jones1, Julia L. Newton1 1Newcastle University, Newcastle Upon Tyne, UK

Autonomic dysfunction (AD) is a frequent finding in the autoimmune liver disease Primary Biliary Cirrhosis (PBC). This study examined structural lesions in 29 early stage PBC patients. Lesions were quantified on T2w images by two trained, independent observers according to the Scheltens scale. Autonomic function of the patients was assessed using a continuous beat-to beat Taskforce system. Total lesion load and lesion load in the globus pallidus was found to correlate with impaired baroreflex sensitivity. This is consistent with AD arising in PBC secondary to central effects.

2163. DTI Reveals Widespread White Matter Abnormalities in Myotonic Dystrophy Type 1 and Type 2 Populations Daniel T. Franc1, Bryon Mueller, Joline Dalton, Cameron Naughton, John W. Day, Kelvin O. Lim 1University of Minnesota, Minneapolis, USA

Significant reductions in fractional anisotropy throughout cerebral white matter were observed in three Myotonic Dystrophy populations.

2164. Correlation Between Regional Cerebral Volumes and Markers of Renal Function in Chronic Kidney Disease Patients Joshua Francis Betz1, 2, Stephen L. Seliger, David Lefkowitz, Jiachen Zhuo, Shari R. Waldstein, Leslie I. Katzel, Rao P. Gullapalli 1University of Maryland Baltimore County, Baltimore, USA; 2University of Maryland, Baltimore, USA

Chronic Kidney Disease is associated with a number of factors implicated in structural and functional changes in the brain. The goal of the study is to elucidate relationships between clinical markers of renal function and structural changes related to aging. After controlling for the effects of age, clinical markers of renal function and cardiovascular health were related to lower region-specific measures of white and gray matter, and higher region-specific measures of cerebrospinal fluid in patients with Chronic Kidney Disease. Our research indicates that Chronic Kidney disease is related to morphological changes which are detectable through quantitative cranial MRI.

2165. The [Ins]/[NAA] Ratio is Highly Correlated with Clinical Score in Huntington’s Disease, Likely Reflecting Simultaneous Astrogliosis and Neuronal Loss Myriam Chaumeil1, 2, Hélène Bataille1, Fawzi Boumezbeur1, Julien Valette1, Anne-Catherine Bachoud-Levi3, Philippe Hantraye2, Vincent Lebon1, 2, Pierre Brugières3 1NeuroSpin, Gif-sur-Yvette, France; 2MIRCen, Fontenay-aux-Roses, France; 3Hôpital Henry Mondor, Créteil, France

Metabolic abnormalities associated with Huntington’s Disease (HD) can be detected by NMR spectroscopy. Up to now 1H spectroscopy in HD has revealed almost systematic decreases in N-acetyl-aspartate and occasional increases in lactate and glutamate+glutamine. Although the glial marker myo-inositol could be a potential marker of degeneration, it has not been quantified yet in the adult form of HD. In this study short echo time 1H spectroscopy of the striatum was combined with LCmodel analysis in order to quantify myo-inositol in HD patients. We observed significantly elevated Ins in the striatum and strong correlation of the Ins/NAA ratio with clinical scores.

2166. MRI T2 Hypointensity Load and Gray Matter Loss in Patients with Huntington’s Disease Radu Serban Jasinschi1, Ahmet Ekin1, Adriaan van Es2, Mark Augustinus van Buchem2, Rene Engbers3, C. Damkat1, Caroline Jurgens2, Jeroen van der Grond2 1Philips Research, Eindhoven, Netherlands; 2Leiden University Medical Center, Leiden, Netherlands; 3Tass, Eindhoven, Netherlands

We investigate two MRI features computed in the Basal Ganglia (BG) of Huntington’s disease (HD) patients. One feature is the hypointensity load in T2-weighted (T2-w) images, and the other one corresponds to gray matter (GM) loss detected in T1-weighted (T1-w) images. We automatically select BG regions [2] given by a set of grid cells which define the region-of-interest (ROI). The T2-w hypointensity load within the ROI is computed by comparing image brightness with a threshold determined based on ROC curve analysis. The tissue segmentation was implemented based on a K-harmonic means clustering algorithm. We tested these two features on 28 subjects, 14 HD patients and 14 controls. We found out that, on average, the percentage of hypointense pixels in the BG is 3.95 times higher for HD patients compared to the controls. Also, the HD patients have 87 % less GM compared to controls, and about 8 % more white matter (WM), significant at p = 0.05 in t-test.

2167. Voxel-Based Morphometry in the Mouse Brain: The R6/2 Huntington's Disease Model Stephen J. Sawiak1, Guy Barnett Williams1, Nigel I. Wood1, A J. Morton1, T A. Carpenter1 1University of Cambridge, Cambridge, UK

Mouse models of disease are of increasing importance, in part because of the comparative ease of developing transgenic variants. Growing amounts of data make traditional analysis techniques such as histology prohibitive. Whilst MRI offers the potential for in-vivo investigation, the analysis problem is not yet fully addressed. Here we present our work in extending automated voxel-based morphometry techniques to the mouse brain, using the popular statistical parametric mapping (SPM) package. Although our work is applicable to any mouse brain model, here we present our methods and results from the R6/2 model of Huntington's disease with 87 three-dimensional, high resolution datasets.

Poster Sessions

361

2168. Presymptomatic Detection of Brain Abnormalities in a Transgenic Ratmodel for Huntington' Disease Using in Vivo Diffusion Tensor Imaging Ines Blockx1, Nadja Van Camp, 12, Marleen Verhoye1, Johan Van Audekerke1, Huu Phuc Nguyen3, 4, Stephan Von Horsten3, Olaf Riess5, Annemie Van der Linden1 1University of Antwerp, Antwerp, Belgium; 2Commissariat a L'Energie Atomique - CEA, Orsay, France; 3Medical school of Hannover, Hannover, Germany; 4University of Tubingen , Germany; 5University of Tubingen, Germany

Diffusion tensor imaging has been widely used for detailed analyses of tissue morphology and pathology. Previous DTI studies have successfully demonstrated neurodegenerative changes in a lesion model of Huntington Disease. Transgenic models provide the advantage of mimicking the human pathology more closely and in addition they display a more progressive course of the disease. We aimed at revealing the first signs of neurodegeneration by investigating changes of microstructure and neuroconnectivity in young presymptomatic (2 months) transgenic animals. The results of this study will be highly valuable for pre-clinical screening as well as for the understanding of the specific underlying pathogenesis.

2169. Imaging the Progression of Brain Atrophy in a Mouse Model of the Huntington’s Disease Jiangyang Zhang1, Kenichi Oishi1, Qi Peng1, Qing Li1, Michael I. Miller2, Susumu Mori1, Wenzhen Duan1 1Johns Hopkins University School of Medicine, Baltimore, Maryland, USA; 2Johns Hopkins University, Baltimore, Maryland, USA

We studied the progression of brain atrophy in R6/2 mice, a model of Huntington’s disease, using in vivo longitudinal MRI. High resolution images captured macroscopic changes in brain morphology from three weeks to 12 weeks after birth in the same animals. Quantitative analysis revealed atrophy in the striatum, motor and pimiform cortex, as well as enlargement of the lateral ventricles in 5 week old mice. Longitudinally, the rates of brain atrophy were not uniform. Our results suggested that atrophy in the striatum was most active at around 5 weeks old.

2170. Voxel-Based Morphometry Study in Restless Legs Syndrome (RLS): Volumetric Increase in Multiple Brain Regions Byeong-Yeul Lee1, Jeffrey Vesek1, Shoaib Alam1, James R. Connor1, Qing X. Yang1 1Penn State Univeristy College of Medicine, Hershey, Pennsylvania, USA

Restless leg syndrome (RLS) is a sensory-motor disorder coupled with iron deficiency in the RLS brain. It is not known whether or not RLS brain volume is different from normal control. We hypothesize that insufficient iron concentration in RLS may contribute to the global regional change. To test our hypothesis, we conducted a voxel-based morphometry study on RLS. Our data demonstrate that a significant volumetric increase was found in the gray and white matter in RLS. Thus, we may speculate that iron deficiency contribute to the increase in volume in RLS patients compared to controls.

2171. Decreased R2 and Increased Concentrations of Multiple Cerebral Metabolites in the Restless Legs Syndrome (RLS) Brain: Exploring Iron Deficiency Consequence in RLS Byeong-Yeul Lee1, Jeffrey Vesek2, Elana Farace2, Shoaib Alam2, James R. Connor2, Qing X. Yang2 1Penn State University College of Medicine, Hershey, Pennsylvania, USA; 2Penn State Univeristy College of Medicine, Hershey, Pennsylvania, USA

Restless legs syndrome (RLS) is a neurological disorder in which iron deficiency in central nervous system is a contributing factor. However, in vivo human studies which link iron deficiency to brain metabolism in RLS brain have not been previously reported. Using in vivo MRI and proton MRS, we investigated the effect of insufficient iron contents on the neurochemical metabolism in RLS.The result showed that decreased in R2 values and increase in various metabolite concentrations in the RLS brain. Thus, the findings of our study may provide insight into neurochemical derangements resulting from iron deficiency in RLS.

2172. Metabolic Changes in the Thalamus of Restless Legs Syndrome Patients: Preliminary 1H-MRS Findings Giovanni Rizzo1, 2, Pasquale Montagna1, Caterina Tonon1, Roberto Vetrugno1, Claudia Testa1, Giuseppe Plazzi1, Federica Provini1, Bruno Barbiroli1, Raffaele Lodi1 1University of Bologna, Bologna, Italy

Restless legs syndrome (RLS) is a common disorder in the general population. The pathophysiology of RLS is poorly understood. Recent studies have suggested a potential thalamic involvement. We performed a 1H-MRS study in patients with RLS and normal controls selecting a volume of interest at the level of the medio-posterior region of the thalamus, in order to identify metabolic changes in this structure. In RLS patients we detected a significant reduction in NAA/Cr and in the absolute concentration of NAA. Our preliminary spectroscopic data confirm a thalamic involvement in RLS patients.

2173. Global Brain Iron Deficiency in Restless Legs Syndrome Examined by an Increase of T2-Values Jana Godau1, Katharine Schweitzer1, Adriana Di Santo1, Daniela Berg1, Uwe Klose1 1University Hospital Tuebingen, Tuebingen, Germany

Restless Legs Syndrome (RLS) is a disorder, for which brain iron deficiency is suspected. In this study with RLS patients, we examined alterations of the T2 relaxation, which is expected to occur with reduced iron content. T2-values were calculated from 2 echoes from a Turbo spin-echo sequence. Circular ROIs were bilaterally placed in ten selected regions. In every examined brain region the average T2 value histogram plots were remarkably shifted to higher T2 intensities in the RLS patient group. Increased T2 values in RLS patients compared to controls suggest decreased iron content in all examined brain regions.

2174. Factor Analysis Reveals Metabolic Differences in Macaques with SIV/AIDS and Encephalitis Margaret R. Lentz1, Vallent Lee1, Susan V. Westmoreland2, Eva-Maria Ratai1, Elkan F. Halpern3, R. Gilberto Gonzalez1 1Massachusetts General Hospital, Charlestown, USA; 2New England Primate Research Center, Southborough, USA; 3Massachusetts General Hospital, Boston, USA

1H MRS provides multivariate data on metabolites in the HIV-infected brain, and can benefit from the use of factor analysis (FA). We applied FA to identify patterns in the metabolic processes underlying the pathogenesis of neuroAIDS, using frontal cortex extracts from SIV-infected macaques moribund with AIDS. One factor could discern between SIV/AIDS animals and healthy controls. Another factor could distinguish animals with encephalitis, and was significantly different across classifications of encephalitis severity. We demonstrate the strengths of FA and discuss the implications that the data raise regarding the analysis of in vivo MRS.

Poster Sessions

362

2175. Glutamate is Reduced in the Frontal Lobe of HIV Patients Napapon Sailasuta1, Kimberly Shriner2, Brian Ross1 1Huntington Medical Research Institutes, Pasadena, California , USA; 2Huntington Hospital, Pasadena, California , USA

First report of direct measurement of brain glutamate concentrations in HIV patients

2176. Increased GABA in Basal Ganglia of HIV-Infected Adults Measured by 1 H MRS Kevin Wayne Waddell1, David W. Haas1, Robin Avison1, Parham Zanjanipour2, Subechhya Pradham3, John C. Gore1, Rebecca Basham, Kirsten L. Haman1, Malcolm J. Avison1 1Vanderbilt University, Nashville, USA; 2University of Kentucky, Lexington, USA; 3Vanderbilt, Nashville, USA

The basal ganglia are rich in GABA innervations and show evidence of HIV within weeks of infection and bear a high viral burden. We therefore hypothesized that altered GABA metabolism in this region may be an early consequence of HIV infection and used a robust and reproducible GABA editing protocol to compare basal ganglia GABA levels in chronically infected, relatively immunocompetent, neurocognitively intact HIV+ patients who were not receiving antiretroviral treatment, with those of presumed non-infected control subjects. In this small cohort, GABA levels in the HIV+ group were approximately 150% higher than in normal (healthy) volunteers.

2177. Lower NAA Correlates with CD16+ Monocyte Expansion During Primary/Early HIV Infection Margaret R. Lentz1, Woong-Ki Kim2, Vallent Lee1, Kenneth Williams3, Eric Rosenberg4, R. Gilberto Gonzalez1 1Massachusetts General Hospital, Charlestown, USA; 2Eastern Virginia Medical School, Norfolk, USA; 3Boston College, Chestnut Hill, USA; 4Massachusetts General Hospital, Boston, USA

1H MRS has demonstrated that brain metabolism changes in chronic HIV infection, and animal studies have suggested that neuronal injury and inflammation may also be occurring in primary (acute) infection. We report the validation of metabolic changes during primary/early HIV infection, and their correlation with immunologic factors. Subjects with primary/early HIV infection had lower levels of neuronal marker NAA and a greater proportion of monocytes in their blood. Further analysis shows that neuronal injury is correlated to the expansion of a specific subset (CD16+) of monocytes, signifying the possible establishment of the brain as a viral reservoir early during infection.

2178. An MRI Study of Rat Model of Cryptococcal Meningo-Encephalitis Ami Pai1, Rohit Sood1 1University of New Mexico, Albuquerque, New Mexico, USA

C. neoformans meningoencephalitis (CNME) is the commonest fungal infection associated with the death of HIV infected patients. Newer pharmaceutical based treatment options for CNME require testing in animal models. A critical step in the evaluation of newer drug treatments is to be able to assess drug efficacy in the same animal over time. MRI provides the optimal framework for performing drug studies in rat models due to its non-invasive nature and ability to follow the longitudinal course of the disease in the same animal. In this study, MRI has been used to characterize a rat model of CNME and the MRI results have been compared with histological findings. Initial results suggest that intracerebral lesions due to CNME were well visualized using MRI. Additionally, MRI results were in good agreement with findings from the histopathological staining method.

2179. Quantitative Analysis of Metabolic Alterations in a Mouse Model of Neuro-Inflammation Using in Vivo MR Spectroscopy Adriana Bucur1, Arlette Bernard2, Cristina Cudalbu1, Pascale Giraudon2, Danielle Graveron-Demilly1, Hélène Ratiney1, Sophie Cavassila1 1CNRS UMR 5220, Inserm U630, INSA-Lyon, Université de Lyon, Université Lyon 1, Villeurbanne, France; 2Inserm U842, Faculté Laennec, Lyon, France

Quantification of the NMR spectroscopic observable metabolites can provide considerable biochemical information and can help clinical investigators in understanding the role of metabolites in normal and pathological conditions associated with neuro-inflammation disease. The aim of the present study was to monitor the metabolic changes in a mouse model of neuro-inflammation. Significant concentration changes of NAA, Lac and Tau were detected from the early stages of the neuro-inflammation. The decrease of NAA has been described in neuronal insults and may sign a neuronal suffering virus-induced. Taurine has been thought to be essential for the development and survival of neural cells and to protect them under cell-damaging conditions and its release could constitute an important mechanism against excitotoxicity. High concentration of Lactate may indicate alterations of oxidative phosphorylation seen in pathological condition of anaerobic metabolism. In conclusion, MRS is useful to detect metabolic dysfunctions from the early stages and investigate the outcome of neuro-inflammation disease.

2180. New Perspectives for Vascular Dementia Patients at 7T! Jens Matthias Theysohn1, 2, Oliver Kraff1, 2, Stefan Maderwald1, 2, Wolfgang P. Becker1, 2, Markus Barth1, 3, Lena Schaefer1, 2, Susanne C. Ladd1, 2, Michael Forsting1, 2, Mark E. Ladd1, 2, Elke Ruth Gizewski1, 2 1University Duisburg-Essen, Essen, Germany; 2University Hospital Essen, Essen, Germany; 3F.C. Donders Centre for Cognitive Neuroimaging, Nijmegen, Netherlands

Introduction of 7 Tesla MRI systems for human imaging is an important development which might provide potential for further perfecting clinical diagnostics. The purpose of this study was to evaluate the value of 7 Tesla MRI in the assessment of cerebrovascular alterations as seen in vascular dementia (VD). Eight patients with known microangiopathy and/or microbleeds were examined. Improved detection of microbleeds coupled with good visualization of white matter lesions at 7T might have significant impact on the early diagnosis of cerebrovascular patients, and provide additional criteria to optimize antithrombotic treatment.

Poster Sessions

363

2181. Assessment of BBB Damage in Patients with VCI Using MRI Saeid Taheri1, Heiko Neeb2, N J Shah2, Gary Rosenberg1, Rohit Sood1 1University of New Mexico, Albuquerque, New Mexico, USA; 2Institute for Medicine, Julich, Germany

Vascular Cognitive Impairment (VCI) is a neurological disorder characterized by dementia with histopathological evidence of cerebrovascular disease and neuroimaging findings of multiple infarctions and white matter (WM) abnormalities. It has been postulated the white matter abnormalities in these patients may be associated with BBB damage. In this study, an MRI technique has been used to quantify BBB damage by measuring BBB permeaility. The technique has been developed and successfully implemented in an animal model of stroke and in this study has been used to accurately quantify BBB damage in patients with VCI. Initial results suggest that white matter lesions are associated with high permeability and are regions of active BBB damage. This study is an example of the role of translational research in improving patient care.

2182. Detection of Stroke and Microbleeds Using Susceptibility Weighted Imaging Muhammad Ayaz1, 2, Ewart Mark Haacke1, 2, Alexander S. Boikov1, Elena S. Manova2, April Dickson3, Cindy Dickson3, Grant McAuley3, Wolff Mayer Kirsch3, Daniel Kido3, Floyd F. Peterson3, William G. Britt3, James P. Larsen3 1The MRI Institute for BioMedical Research, Detroit, USA; 2Wayne State University, Detroit, USA; 3Loma Linda University, Loma Linda, USA

Microbleeds (MBs) are associated with vascular dementia (VaD) and cerebral amyloid angiopathy (CAA). These MBs are small hemorrhages resulting from vessel wall injury from CAA. Patients with VaD have a higher risk of developing MBs. Susceptibility Weighted Imaging (SWI), a high resolution gradient echo imaging technique, is sensitive to hemosiderin even for arteriole bleeds and has revealed MBs much smaller than 5 mm (above which they are usually referred to as macrobleeds). There is also an association between MBs and stroke. The purpose of this paper is to examine the presence of developing major bleeds over time for Alzheimer patients

2183. Defining and Categorizing Microbleeds (MB) in Neurodegenerative Disease Using SWI Muhammad Ayaz1, 2, Ewart Mark Haacke1, 2, Alexander S. Boikov1, Wolff Mayer Kirsch3, Daniel Kido3 1The MRI Institute for BioMedical Research, Detroit, USA; 2Wayne State University, Detroit, USA; 3Loma Linda University, Loma Linda, USA

Microbleeds(MB) in aging is gaining more and more attention. Most studies include a large number of subjects and are snapshots of variety of ages and conditions. These studies discuss the roles of cerebral amyloid angiopathy(CAA), intracranial hemorrhage(ICH) and signal-hyperintensites. The purpose of the current study is to use Susceptibility Weighted Imaging(SWI) to follow a set of 6 subjects and to find and categorize the types of MB that occur in these subjects. No previous study clearly defines when to call a signal loss a microbleed (especially with MB as small as a few pixels) nor has anyone categorized these MBs

2184. DTI Analysis of White Matter Deficits in Frontotemporal Lobular Dementia Jane Asmuth1, Hui Zhang, Murray Grossman, James Gee 1University of Pennsylvania, Philadelphia, Pennsylvania, USA

Diffusion tensor imaging is used to compare underlying white matter differences between three patient subgroups of frontotemporal lobular dementia

2185. Regional Brain Metabolite Pattern in Fronto-Temporal Dementia Sanjeev Chawla1, Sumei Wang1, John H. Woo1, Lauren B. Elman1, Leo F. McCluskey1, Elias R. Melhem1, Murray Grossman1, Harish Poptani1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA

We performed multivoxel magnetic resonance spectroscopy on fifteen patients with frontal-temporal dementia (FTD) and six controls to assess metabolic abnormalities in prefrontal cortex (PFC) and motor cortex (MC) and parietal cortex (PC). A significant reduction in N-acetyl aspartate (NAA) and creatine (Cr) and increase in choline (Cho) and myo-inositol (mI) was observed from the PFC of patients compared to controls. Significantly lower NAA and higher Cho concentrations were also observed in MC of patients. Within patients, both MC and PFC exhibited significantly lower NAA and higher Cho compared to PC. Only PFC had significantly lower Cr and significantly higher mI compared to PC.

2186. Altered Functional Connectivity in Aged Rat Model of Postoperative Cognitive Dysfunction Peng Xie1, 2, Tian Yu1, 2, Xiao-yun Fu1, 2, Ye Tu1, 2, Su Lui2, Xu-na Zhao3, Hua-fu Cheng4, Xiao-qi Huang2, Ti-jing Zhang2, Xiu-li Li2, Qiang Yue2, Dong-ming Li2, Qi-yong Gong2, 5 1Affiliated Hospital of Zunyi Medical College, Zunyi, People's Republic of China; 2Huaxi MR Research Center (HMRRC),West China Hospital of Sichuan University, Chengdu, People's Republic of China; 3Philips Medical System, Beijing, People's Republic of China; 4School of Science and Technology, University of Electronic Science and Technology, Chengdu, People's Republic of China; 5Division of Medical Imaging, Faculty of Medicine, University of Liverpool, UK

Postoperative cognitive dysfunction (POCD) is a common complication occurs after cardiac and major non-cardiac surgery with general anesthesia in the elderly, but its causes and mechanism remains unclear to date. Present study aims to use resting-state fMRI to explore changes of the functional connectivity in animal model of POCD on aged rats. Our findings implied that the change of functional connectivity in the related cortex and hippocampus maybe one of the underlying causes for the cognitive deficit presented after surgery. Further study on human beings will help to clarify the similar clinical profiles in POCD.

Poster Sessions

364

2187. Voxel-Based T2 Relaxometry Detects Brain Injury in Autonomic and Cognitive Regulatory Areas in Patients with Heart Failure Rajesh Kumar1, Mary A. Woo1, Paul M. Macey1, Stacy L. Serber1, Ronald M. Harper1 1UCLA, Los Angeles, USA

Heart failure (HF) patients often show severe autonomic, emotional, and cognitive deficits which could only result from brain alterations; yet, there are few reports describing brain injury in this group. We assessed neural injury in HF and controls using voxel-based T2 relaxometry. Higher T2 relaxation values in HF, indicating areas of injury, emerged in hypothalamus, solitary tract nucleus, hippocampus, cerebellum, caudate, thalamus, anterior fornix, corpus callosum, cingulate, and insula. The affected structures are essential to maintain autonomic, mood and cognitive functions. The mechanisms underlying damage are unclear, but may result from ischemic or hypoxic processes.

2188. White Matter Alterations in Callosal Agenesis: A Diffusion Tensor Imaging Study Michael Wahl1, 2, Elliott H. Sherr1, Anthony James Barkovich1, Steven W. Hetts1, Mari Wakahiro1, Pratik Mukherjee1 1University of California, San Francisco, San Francisco, California , USA

Testing. Fill in later.

2189. In Vivo MRI and MRA at 9.4T Show How (LT) α–TNF Receptor 2 or LTβ Receptor Deficiency on Mutant Mice Affects the Development of Experimental Malaria Dieudonnée Togbe1, Paulo Loureiro de Sousa2, Mathilde Fauconnier1, Victorine Boissay1, Lizette Fick3, Stefanie Scheu4, Klaus Pfeffer4, Robert Menard5, Georges Grau6, Laurent Renia7, Bernhard Ryffel1, Valérie Quesniaux1, Bich-Thuy Doan8, Jean-Claude Beloeil2 1University of Orléans, Orléans, France; 2CNRS, France; 3Institute of Infectious Disesase, Cape Town, South Africa; 4University of Dusseldorf, Germany; 5Pasteur Institute, Paris, France; 6The University of Sydney, Australia; 7Institut Cochin, France; 8CNRS, Gif sur Yvette, France

Cerebral malaria is a frequent cause of death in children infected with Plasmodium falciparum, which is characterized by the sequestration of parasitized erythrocytes in cerebral blood vessels.In this work, investigations on experimental cerebral malaria (ECM) revealed that the lymphotoxin α (LTα) and signaling through TNFR2 are critical. Indeed, LTβR and LTαβ deficient mice, did not develop the neurological signs contrary to C57BL/6J wild type and TNF deficient mice.T2 and angiographic MRI were used to verify the lack of ischemia and microvascular pathology in TNF, LTαβ and LTβR deficient malarial mice. The results were validated by histological studies.

Brain Tumor: Perfusion, Diffusion & Contrast Techniques Hall D Monday 14:00-16:00

2190. Validation of Neuroradiologic Response Assessment in Adult Glioblastoma: Cross-Comparison of Linear and Volumetric Methods on Post-Contrast Standard Thick and High Resolution T1WI Mei-Yun Wang1, Jing-Liang Cheng2, Wei-Ting Zhang1, Ming-Wang Zhu1, Craig Peterson1, Poe-Zhou Chen1, Heisoog Kim1, Prescilla Yeo1, Jie Bai2, Hui-Xia Zhang2, Yan Du2, A Gregory Sorensen1 1Massachusetts General Hospital, Charlestown, Massachusetts, USA; 2the First Affiliated Hospital of Zhengzhou University, Zhengzhou, People's Republic of China

The improvement of imaging technology and volume measurement software has made volumetric method become a more practical and promising end point for evaluating tumor response status in GBM. This study showed that volumetric method has more sensitivity and accuracy than linear method in detecting tumor response in adult GBM, particularly volume on post-contrast high resolution T1WI; volume on post-contrast thick T1WI may be taken an alternative to volume on post-contrast high resolution T1WI when considering the advantage of less time-consuming in both image acquisition and volume measurement.

2191. MRI for Evaluation of Brain Lesions: Intraindividual Comparison of Gadobenate Dimeglumine vs Conventional Gadolinium Contrast Agents Howard A. Rowley1, Guiseppe Scialfa2, Pei-yi Gao3, Kenneth R. Maravilla4, Joseph A. Maldjian5, Matthew J. Kuhn6 1University of Wisconsin, Madison, Wisconsin, USA; 2Hospital Niguarda Ca'Granda, Milan, Italy; 3Beijing Tian Tan Hospital, Beijing, People's Republic of China; 4University of Washington, Seattle, Washington, USA; 5Wake Forest University, Winston-Salem, North Carolina, USA; 6Southern Illinois University, Springfield, Illinois, USA

The enhancement provided by a unique contrast agent with transient protein interaction (gadobenate dimeglumine) was compared with enhancement after other non-protein interacting gadolinium contrast agents in two large scale trials. The greater enhancement seen after gadobenate dimeglumine at a dose of 0.1 mmol/kg bodyweight may prove beneficial for presurgical patient management decisions by more accurately defining the extent of disease in patients with cerebral gliomas or brain metastases. Better definition of radiosurgical target volumes and better selection of patients for whom surgical intervention would not prove beneficial may potentially improve prognosis or quality-of-life in this group of patients.

2192. Initial Area Under the Curve (IAUC) is an Objective, Pragmatic and Translatable MRI Biomarker for Quantifying Human Brain Tumor Perfusion: Correlation with Histopathology Bradford Armstrong Moffat1, Catherine Klotz2, Amanda Lovell2, Soren Christensen2, Patricia M. Desmond2 1University of Melbourne, Parkville , Australia; 2University of Melbourne, Parkville, Australia

In this study the normalized initial area under the time curve (IAUC) was quantified in 21 high grade brain tumor patients. This model free analysis allowed for a completely objective measure of brain tumor perfusion. In addition it was able to distinguish and predict WHO histopathological subtype. This suggests that IAUC has the potential to be a pragmatic and translatable MRI biomarker for imaging brain tumor angiogenesis.

Poster Sessions

365

2193. Contrast-Enhanced MR Imaging of the Central Nervous System in Children: Evaluation of Gadobenate Dimeglumine Matthew J. Kuhn1, Pei-yi Gao2, Claudio Fonda3, Emilio Cianciulli4, Mieczyslaw Pasowicz5 1Southern Illinois University, Springfield, Illinois, USA; 2Beijing Tian Tan Hospital, Beijing, People's Republic of China; 3Anna Meyer Pediatric Hospital, Florence, Italy; 4 “Santobono Pausillipon” Children’s Hospital, Naples, Italy; 5John Paul II Hospital, Krakow, Poland

A multinational clinical trial of the safety and efficacy of 0.1 mmol/kg Gd-BOPTA for MRI of the CNS in children is described. To date, 71 children have been enrolled. Gd-BOPTA was well tolerated by all children enrolled: 4 mild adverse events have been reported, and no clinically meaningful changes in laboratory parameters/ECGs have been observed. In all children with enhancing lesions, contrast enhancement was considered good to excellent. Compared to unenhanced images, Gd-BOPTA resulted in improved evaluation of the extent of disease, lesion border delineation, and lesion internal morphology.

2194. The Functional Perfusion Map: A Novel Imaging Biomarker for Early Prediction of Tumor Patient Response Craig J. Galbán1, Daniel A. Hamstra1, Charles R. Meyer1, Pia Sundgren1, Christina Tsien1, Theodore S. Lawrence1, Alnawaz Rehemtulla1, Thomas L. Chenevert1, Brian D. Ross1 1University of Michigan, Ann Arbor, Michigan, USA

We describe a novel, perfusion MRI approach which provides an imaging biomarker capable of early prediction of treatment response in glioma patients. Perfusion MRI was performed on 45 patients pre and post-treatment. Voxel-wise differences in relative cerebral blood volume (rCBV) maps were calculated as a functional perfusion map (fPMrCBV). Survival analysis was performed by stratification of patient outcome based on fPMrCBV or percent difference of mean rCBV. In contrast to mean rCBV, overall survival was closely associated to fPMrCBV. This study provides a potentially standardized method for using perfusion MRI as an early predictor of cancer patient treatment response.

2195. Self-Learning Predictive Modeling in Glioma Grading Kyrre Eeg Emblem1, 2, Bjorn Tennoe1, Baard Nedregaard1, Terje Nome1, Paulina Due-Tonnessen1, John K. Hald1, David Scheie1, Atle Bjornerud1, 2 1Rikshospitalet, Oslo, Norway; 2University of Oslo, Oslo, Norway

Studies have shown that cerebral blood volume (CBV) maps derived from MR perfusion can improve glioma grading. However, the current grading methods are prone to user-bias. An important step towards a user-independent, automated glioma grading is the need to develop self-learning predictive models. In this study, we have developed and evaluated four self-learning predictive models based histogram analysis of CBV heterogeneity. Preliminary results suggest that the predictive models are able to correctly predict glioma grade in 7-8 out of 10 patients, and the ability to correctly grade new glioma cases increase with the number of cases in the reference database.

2196. DSC-MRI Estimates of Perfusion Predict Survival in Brain Tumor Patients Kathleen Marie Schmainda1, 2, Devyani Bedekar1, Eric S. Paulson1, Scott D. Rand1, Hendrikus G J Krouwer 1Medical College of Wisconsin, Milwaukee, Wisconsin, USA

Survival is the primary measure used to evaluate the success of new treatments in brain tumor and other patients. However, analysis of survival requires studying a large cohort of patients and estimating survival long after the treatment study has ended. Consequently, an imaging biomarker, which is predictive of survival early on, has the potential to improve the efficiency of clinical drug trials and patient management in the short term. Here we demonstrate that both GE rCBV (relative cerebral blood volume) and mVD (mean vessel diameter) information, derived from DSC perfusion studies, and obtained at initial diagnosis are predictive of survival.

2197. MR Perfusion Imaging and Voxel-Based Diffusion Tensor Imaging of Non-Enhancing Cerebral Gliomas Xiang Liu1, Wei Tian1, Sven Ekholm1, Per-Lennart Westesson1 1University of Rochester School of Medicine & Dentistry, Rochester, New York, USA

14¨C45% of non-enhancing supratentorial gliomas, which are usually misdiagnosed as low grade glimoas (WHO grade 1and 2) because of lack of enhancement, are malignant(WHO grade 3 and 4). Thus it is important of correct pre-operative grading in non-enhancing cerebral gliomas, but which is difficult by conventional MR imaging. We speculate that MR perfusion weighted imaging(PWI) and diffusion tensor imaging(DTI) will be benefit for differentiating low grade with high grade non-enhancing supratentorial gliomas. 33 patients with pathology confirmed non-enhancing supratentorial glioma were enrolled in this study. Maximal ratio of relative cerebral blood volume (rCBV), trace apparent diffusion coefficient ( trace ADC) and Fractional anisotropy (FA) in the tumor were calculated and compared between low grade group and high grade group. There is significant difference of maximal ratio of rCBV and FA between low grade(rCBV 0.931¡À0.056, FA 0.128¡À0.033 ) and high grade group(rCBV 3.91¡À2.87, FA 0.356¡À0.133) (P=0.000, by Mann-Whitney U test) . About 96% patients could be classified correctly based on maximal ratio of rCBV of 1.75 and cutoff FA value of 0.21. There is no significant difference of mean trace ADC value between groups(P>0.05). Our study proves that there is increased perfusion and higher anisotropy changes in the high grade non-enhancing supratentorial glioma. Combing MR PWI and DTI are useful in the accurate pre-operative grading non-enhancing supratentorial gliomas.

2198. MR Measurements of Pre-Treatment Tumour Perfusion Appear to Correlate with Response to Dexamethasone in Patients with Gliobastoma Multiforme Paul A. Armitage1, Chris Schwindack1, Mark E. Bastin1, Ian R. Whittle1 1University of Edinburgh, Edinburgh, UK

Dynamic susceptibility contrast MRI (DSC-MRI) and dynamic contrast-enhanced MRI (DCE-MRI) were used to obtain measurements of tumour perfusion and permeability in a series of nine glioblastoma multiforme patients imaged before and 48 -72 hr following administration of dexamethasone. Pre-treatment tumour perfusion was correlated with pre-post treatment changes in DCE-MRI parameters. A strong correlation was found between pre-treatment tumoural blood flow and tumoural blood volume and the resulting treatment effect as measured by DCE-MRI. The results suggest that pre-treatment measurements of tumour perfusion may be useful predictors of response to brain tumour therapies.

Poster Sessions

366

2199. Differentiation of Recurrent Intra-Axial Metastatic Tumor from Delayed Radiation Effects of Gama Knife Radiosurgery Using Dynamic Susceptibility Weighted Contrast Enhanced Perfusion MR Imaging Ramon Francisco Barajas Jr. 1, Jamie Chang1, Patricia K. Sneed, Soonmee Cha 1University of California San Francisco, San Francisco, California , USA

The purpose of our study was to determine whether relative cerebral blood volume (rCBV), relative peak height (rPH), and percentage of signal intensity recovery (PSR) derived from DSC perfusion MR imaging can differentiate recurrent tumor from the delayed effects of radiation in patients previously treated with gamma knife radiosurgery for metastatic intra-axial tumors. Thirty four cases were retrospectively investigated by drawing regions of interest around contrast enhancing areas producing T2* signal intensity-time curves. We found that mean PSR values were lower (P <0.01) and rCBV and rPH values were higher (P <0.024) in cases of recurrent tumor.

2200. Preclinical MRI Evaluation of Human Glioblastoma Response to an Anti-Angiogenic Treatment Benjamin Lemasson1, 2, Thomas Christen2, 3, Regine Farion2, 3, Emanuel Barbier2, 3, Xavier Tizon1, Christoph Segebarth2, 3, Philippe Genne1, Olivier Duchamp1, Chantal Remy2, 3 1Oncodesign Biotechnology, Dijon, France; 2Inserm U836, Grenoble, France; 3Université Joseph Fourier, Grenoble Institut des Neurosciences UMR-S836, Grenoble, France

Despite aggressive surgery, radiotherapy and chemotherapy, malignant gliomas remain uniformly fatal. These tumours stimulate the formation of new blood vessels (angiogenesis). Therapies directed against tumour vasculature or preventing angiogenesis have recently been developed. Monitoring changes in microvasculature should help to evaluate the efficiency of anti-angiogenic therapies. Recently, MRI has shown its ability to map different microvascular parameters. Moreover, they have the sensitivity to reveal differences between normal and tumoral tissues as well as differences between tumour types. The aim of this work was to apply MRI to evaluate the efficiency of a particular anti-angiogenic therapy on a human glioma model.

2201. Images of Restricted Water in Brain with Applications to Neurosurgery Sharon Peled1, Stephen Whalen, Ferenc Jolesz1, Alexandra Golby 1Brigham and Women's Hospital, Boston, Massachusetts, USA

DTI-based fiber tracking in white matter has become a useful tool for preoperative planning of brain tumor surgery. However, edema and/or tumor infiltration can cause the diffusion anisotropy to be low, causing tractography algorithms to fail in critical areas around tumors. Here we show a clinically applicable DTI-based method for identifying where viable intracellular space still exist by isolating the signal from restricted water in each voxel. The ability to quantify this water also provides a new contrast mechanism whose sensitivity to different pathological states of tissue is under evaluation.

2202. The Use of ADC Parameters to Distinguish Paediatric Brain Tumours Jonathan G. Bull1, Martin D. King1, Dawn E. Saunders2, Christopher A. Clark1 1UCL Institute of Child Health, 30 Guilford Street, UK; 2Great Ormond Street Hospital for Sick Children, Great Ormond Street, UK

A study to discrminate different paediatric brain tumour types using ADC histograms of the tumour volume in 56 histopathologically verified cases. We show that using linear discriminant analysis of the ADC histogram parameters it is possible to discriminate the 3 common posterior fossa tumours and to differentiate between a rare agressive tumour atypical teratoid rhabdoid tuumour (ATRT) and medulloblastoma. This is currently not possible pre-operatively. These findings may diminsh the need for invasive surgical biopsy and its attendant risk of morbidity and mortality.

2203. Serial Diffusion Tensor Imaging Study in Children Receiving Cranial Radiation Firouzeh Tannazi1, Todd McNutt1, Siamak Ardekani2, Doris Lin1, Ori Shokek1, Kenneth Cohen1, Moody Wharam1, Peter Barker1, Susumu Mori3, Alena Horska3 1Johns Hopkins University School of Medicine, Baltimore, Maryland, USA; 2Johns Hopkins University, Baltimore, Maryland, USA; 3Johns Hopkins University School of Medicine,, Baltimore, Maryland, USA

A longitudinal DTI based study was conducted to examine white matter injury associated with radiation therapy (RT) in children with brain tumor. Six patients (8.7-18.7 years old) were examined before, 6, and 15 months after RT. Results were compared to 27 aged matched control subjects (scanned with the same intervals). Initially, in comparison to control subjects, significant drop in FA and increase in ADC values in several regions were detected. However, in 6 and 15 months follow-ups the diffusion parameters tended toward control values. This observation may suggest DTI can capture recovery of brain from acute side effects of radiation.

2204. A Study of Correlation Between Neovascularity and Tumor Infiltration of Gliomas Using Perfusion and Diffusion MRI Shuohui Yang1, John L. Villano1, Girish Srinivasan1, 2, Keith R. Thulborn1, Xiaohong Joe Zhou1 1Univ. of Illinois Medical Center, Chicago, USA; 2University of Illinois at Chicago, Chicago, USA

Neovascularity and tumor infiltration are important characteristics defining glioma growth and aggressiveness. In this study, we have investigated the possible correlation between neovascularity and tumor infiltration of low-grade and high-grade gliomas by employing both perfusion and diffusion tensor imaging (DTI) techniques. Our result in general did not support a spatial correlation between neovascularity revealed by perfusion imaging and tumor infiltration assessed by two DTI parameters. However, the combination of DTI and perfusion imaging may be useful to reveal the temporal relationship between neovascularity and tumor infiltration through a time-course study.

2205. Behavior of DTI Parameters as Functions of Distance from a Tumor Ashok Kumar1, Weiting T. Zhang1, E di Tomaso2, D G. Duda2, R K. Jain2, T T. Batchelor2, Alma Gregory Sorensen1 1A. A. Martinos Center, Massachusetts General Hospital, Charlestown, Massachusetts, USA; 2Masschusetts General Hospital, Boston, Massachusetts, USA

Water-diffusion parameters have a dominant localized behavior as a response to injury. That is, the diffusion tensor eigenvalues vary monotonically from the site of the injury and assume a more normal value far away from the injury. Differerent eigenvalues may vary at different rates with distance. So even though each of them may show a monotonic response, due to their different rates of change, their combined effect on FA is to create a more complicated behavior with distance.

Poster Sessions

367

2206. Quantification of Therapy Induced Cerebral Blood Flow Changes in Pediatric Diffuse Pontine Gliomas and Normal Appearing Brain Parenchyma by Arterial Spin Labeling During Phase I Combined Radiation and Antiangiogenesis Therapy Yong Zhang1, Fred H. Laningham1, Ralf Loeffler1, Ruitian Song1, Josef Pfeuffer2, Alberto Broniscer1, Zoltan Patay1, Claudia M. Hillenbrand1 1St. Jude Children's Research Hospital, Memphis, USA; 2Siemens Medical Solutions, Erlangen, Germany

We used pulsed arterial spin labeling (PASL) to evaluate brain perfusion changes in the first four pediatric patients enrolled in a new Phase I study of diffuse pontine glioma treated with a combination of local radiotherapy and an anti-angiogenic drug. Cerebral blood flow (CBF) measurements were performed in both normal appearing brain parenchyma and in tumor regions at three sequential time points. A similar trend of CBF changes were observed in both regions. Initial success of PASL in detecting and quantifying CBF changes offers potential to use this technique to monitor changes in tumor vasculature induced by treatment.

Amyotrophic Lateral Sclerosis (ALS) Hall D Tuesday 13:30-15:30

2207. Regional Brain Metabolite Changes and Their Correlations with Upper Motor Neuron Function Measures in ALS: Application of a Whole-Brain Proton MRSI Method Varanavasi Govindaraju1, Khema Sharma1, Brian Bowen1, Claudia Domenig1, Andrew Maudsley1 1University of Miami, Miami, USA

Brain metabolites (NAA, CR, and CHO) have been measured at multiple anatomical locations along the corticospinal tract (CST) in subjects with amyotrophic lateral sclerosis (ALS), using a high-spatial resolution whole-brain proton MR spectroscopic imaging method. Metabolite ratios were significantly decreased in many regions, starting from the subcortical white matter of the precentral gyrus to the medulla. Metabolite ratios from 6 anatomical regions correlated strongly with the clinical upper motor neuron (UMN) function measures, suggesting an association between the cerebral metabolite levels and UMN function.

2208. Are There Vascular Deficiencies in Amyotrophic Lateral Sclerosis? Caroline Sage1, Ronald Peeters1, Wim Robberecht1, Stefan Sunaert1 1University Hospitals of the Catholic University of Leuven, Leuven, Belgium

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease predominantly affecting the motor system. Apart from neuronal loss, vascular deficiencies could play a role in the physiopathology of ALS. We performed an fMRI study, assessing the activation pattern in the brain induced by an alternating hyperventilation/breath-hold task. This task allows assessment of the cerebrovascular reactivity, which reflects the ability of the cerebral circulation to adapt the vasomotor tone to vasodilatory or vasoconstrictory stress. The obtained activation patterns were compared to those of healthy age- and sex-matched controls, to evaluate whether vascular deficiencies might contribute to the in vivo physiopathology of ALS.

2209. Regional Average Brain Cortical Thickness and Cognitive Exams in ALS Don Charles Bigler1, Claire Flaherty-Craig1, Ryan Zimmerman2, Helen E. Stephens1, Kevin R. Scott1, Paul J. Eslinger1, Zachary Simmons1, Qing X. Yang1 1Penn State Milton S. Hershey Medical Center, Hershey, Pennsylvania, USA; 2Elizabethtown College, Elizabethtown, Pennsylvania, USA

Increasing evidence suggests that ALS is not simply a motor neuron disease, but a more widespread neurodegenerative process. In this study average thickness in select brain regions was measured and correlated to a cognitive screen exam sensitive to the three recognized FTD syndromes. Significant negative correlation between subtests scores and average thickness were found in temporal and occipital brain regions. These results support the evidence that ALS is a more widespread neurodegenerative disease. Furthermore, MRI validation of this FTD screen exam contributes to the success of approaches to facilitate ALS-FTD decision-making during discussions of treatment planning and end-of-life issues.

2210. Magnetic Resonance and Detailed Histological Analysis of the Primary Motor Cortex in Amyotrophic Lateral Sclerosis Mark David Meadowcroft1, 2, Nathan J. Mutic1, 2, Ryan P. Zimmerman1, James R. Connor1, Zachary Simmons1, Michael B. Smith3, Qing X. Yang1 1Penn State College of Medicine, Hershey, Pennsylvania, USA; 2Vanderbilt University, Nashville, Tennessee, USA; 3Novartis Institutes for BioMedical Research, Inc., Cambridge, Massachusetts, USA

Ex vivo imaging of cadaver brains from ALS patients has relieved signal intensity and relaxation differences in the primary motor cortex compared to other brain regions. The aim of this study is to quantifying the cause of these differences with MR techniques and various histological stains (GFAP, neurofilament, and Luxol fast blue). The data indicate an overall trend of distress within the gray and white matter primary motor cortex in Amyotrophic Lateral Sclerosis.

2211. MRS Study of the Effects of Minocycline on Markers of Neuronal and Microglial Integrity in ALS Abdesslem Khiat1, Yvan Boulanger1, Frédérique Souchon1, Monique D'Amour1 1Centre hospitalier de l’Université de Montréal, Montréal, Canada

Brain proton magnetic resonance spectroscopy was used to study the longitudinal effects of minocycline administration on amyotrophic lateral sclerosis (ALS) patients. Ten newly diagnosed ALS patients were examined by MRS in the precentral gyrus and in the brainstem before minocycline treatment and at three and six weeks after initiation of treatment. Results did not show the expected decrease of NAA/Cr in the precentral gyrus and an increased NAA/Cr ratio in the brainstem suggested neuronal recovery. Increased mI/Cr in the brainstem suggests a glial reaction.

Poster Sessions

368

2212. Image-Based Analysis of Metabolic Alterations with ALS Andrew A. Maudsley1, Varanavasi Govindaraju1, Khema R. Sharma1 1University of Miami, Miami, Florida, USA

Voxel-based analysis of proton-MR-observed metabolite distributions has been applied to a group of subjects with amyotrophic lateral sclerosis. This technique is shown to be able to map the metabolic consequences of neurodegeneration in the corticospinal tracts, as well as showing evidence of more widespread metabolic alterations in the frontal lobe.

2213. In Vivo Detection of Axonal Degeneration in Cervical Spine from a Mouse Model of Amyotrophic Lateral Sclerosis Joong Kim1, Jin-Moo Lee1, Sheng-Kwei Song1 1Washington University School of Medicine, St. Louis, Missouri, USA

In vivo DTI was performed to evaluate neuro-degeneration in brain stem and cervical spinal cord from wild type and G93A-SOD1 transgenic mice, an animal model of ALS. Statistically significant decreases in axial diffusivity and trace were found in the ventrolateral white matter of G93A-SOD1 mice at the cervical spinal cord levels as well as in Nc VII and Nc XII nucleus in brain stem compared to wild type mice. No significant difference was observed in dorsal white matter or gray matter in cervical spinal cord. The presented study showed that in vivo DTI may be used for evaluating axonal degeneration in animal model ALS.

2214. White Matter Impairment in Amyotrophic Lateral Sclerosis (ALS): Diffusion Tensor Imaging and High B-Value DWI Study Artzi Moran1, Orna Aizenstein, Vivian Drory, Beatrice Nefussy, Yaniv Assaf, Talia Zachor, Dafna Ben Bashat 1The Wohl Institute for Advanced Imaging, Tel Aviv Sourasky Medical Center, Israel, Kfar Yona, Italy

White matter impairment in Amyotrophic Lateral Sclerosis (ALS): Diffusion Tensor imaging and high b-value DWI study1Artzi , M., 2,3Drory, V., 2Nefussy, B., 1Zachor. T., 1,3Assaf, Y., 1Aizenstein, 0. 1*Ben Bashat, D.,1The Wohl Institute for Advanced Imaging, TASMC, 2ALS Clinical Department of Neurology, TASMC, 3Tel Aviv University* dafnab@tasmc.health.gov.il Background: Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder of the motor system causing damage to both the upper and lower motor neurons (UMN/LMN). To date, there are no imaging techniques available for objectively assessing the UMN damage. Purpose: to evaluate the cerebral white matter quantitatively using diffusion tensor imaging (DTI) and high b-value diffusion weighted imaging (DWI). Method: MR protocol included T1, T2, DTI (b=1,000 s/mm2) and high b-value DTI (b values up to12, 000 s/mm2). Twenty- three UMN ALS patient and 20 age match healthy volunteers were scanned on a 3T GE MRI scanner. Diffusion tensor tracktography (DTT) was used and mean FA, Prob and Disp were calculated for the motor and sensory fibers separately. Results: Significant reduction in FA was detected in the CST in both axial and coronal data sets (p<0.05) for both sensory and motor fibers, between the study group and the control group. Significant increase in displacement values were also detected in the left CST but not on the right or with the Prob values. Correlations between FA, eigen values and Prob and disease duration was obtained only within a subgroup of patients with bulbar onset (n=5) but not for the whole group of ALS patients. On histogram analysis significant reduction in restriction was observed for Disp and Prob in the gray matter peak only (p<0.05).Our findings provide quantifiable information regarding to the CST degeneration that occurs in ALS. The results showed damage to the white matter as well as to the gray matter, and show damage to the extra motor

Innovative Imaging of the Normal Brain Hall D Wednesday 13:30-15:30

2215. The Normal Anatomy of the Substantia Nigra Using High Field 9T MRI: Correlation of Postmortem Images and Histopathology Mario Alcides Miranda1, Luke A. Massey1, Harry G. Parkes1, So Po-Wah2, John S. Thornton1, Janis Holton1, Laura Mancini3, P Cheshire1, K Strand1, Andrew J. Lees1, Tamas Revesz1, Tarek A. Yousry1 1Institute of Neurology, UCL, London, UK; 2Imperial College School of Medicine, MRC Clinical Sciences Centre, Hammersmith Hospital, London, UK; 3Lysholm Department of Neuroradiology, London, UK

High resolution T2W MRI images at 9.4T of the midbrain targeted on the Substantia Nigra (SN) have been compared with histopathology samples. The detailed micro environment of the SN and the superior midbrain is described. The SN is seen as two layered band of tissue with a hypointense antero-lateral segment (par reticulata) and a hyperintense postero-medial component (pars compacta). This is probable the first MRI description of both segments of the SN (pars reticulata and compacta) that has been achieved.

2216. Susceptibility-Weighted Imaging (SWI) Delineates the Whole Length of the Optic Radiation Nobuyuki Mori1, Yukio Miki1, Chikara Maeda1, Seiko Kasahara1, Shin-ichi Urayama1, Nobukatsu Sawamoto1, Hidenao Fukuyama1, Kaori Togashi1 1Kyoto University Graduate School of Medicine, Kyoto, Japan

This study examined whether low signal-intensity band (LSB) lateral to the lateral ventricles on 3T SWI represented the optic radiation (OR) by measuring profiles of LSB in 4 anatomical planes. Seven healthy volunteers entered. Comparison was also made with diffusion tensor tractography (DTT) of the OR. Measured profiles of the LSBs were consistent with the anatomical literature regarding the OR; even Meyerfs loops were clearly demarcated on SWI. DTT overlapped all LSBs posterior to the geniculate body, while at Meyerfs loop overlapped incompletely. Visualization of the whole length of the OR on SWI may have clinical relevance.

Poster Sessions

369

2217. Quantitative Cytoarchitectural Mapping of the Parahippocampal Region Neda Bernasconi1, 2, Thomas Mansi2, Gheorghe Postelnicu1, Jean C. Augustinack1, Bruce Fischl1 1Athinoula Martinos Center, Massachusetts General Hospital, Harvard Medical School, Boston, USA; 2Montreal Neurological Institute, Montreal, Canada

Our purpose was to delineate cytoarchitectonic borders of parahippocampal region structures based on their laminar cortical pattern on ultra-high resolution MRI at 7T. We obtained ex-vivo 100 ?m isotropic images of the temporal lobe in three neurologically healthy subjects using a multiecho multi flip-angle sequence. The cortex was extracted by solving the Laplace Equation. This process generated streamlines between GM/CSF and GM/WM boundaries, and allowed computing laminar distribution of grey level intensities across the cortex. Applying multivariate statistics on laminar intensity profiles allowed distinguishing cytoarchitectonic borders between parahippocampal subregions that are currently invisible to conventional means of analysis.

2218. High-Resolution in Vivo MR Imaging of the Human Hippocampus at 7 Tesla Zang-Hee Cho1, Kyoung Nam Kim1, Young-Bo Kim1, Kyongtae T. Bae2, Chan-Hong Moon2 1Gachon University of Medicine and Science, Incheon, Republic of Korea; 2University of Pittsburgh, Pittsburgh, Pennsylvania, USA

Volumetric atrophy of the hippocampus is associated with a wide range of neurodegenerative diseases (ND), such as Alzheimer¡¯s disease (AD), and has been thoroughly evaluated at 1.5 or 3 T magnetic field MR imaging. Neuronal deaths precede atrophy of whole hippocampus and affect its subdivisions regionally at different rates. Recent literature concerning in vivo MR imaging of the brain cortex at 7 T proposed that hippocampus layer structures may be discernible with imaging at ~200 μm pixel resolution. Thus, the purpose of our study was to demonstrate the feasibility of high resolution in vivo 7 T MR imaging of the detailed layers of the hippocampus, which may be used as a biomarker for the detection of early stage ND.

2219. Cortical Architecture of the Human Hippocampus Tie-Qiang Li1, Bing Yao1, Peter van Gelderen1, Hellmut Merkle1, Alan Koresky1, Jeff Duyn1 1NINDS, Bethesda, Maryland, USA

High resolution T2*-weighted MRI was used to study the hippocampus of the human brain at 7T. Both the magnitude and phase information were analyzed to provide complementary information about the details of the cortical architecture in and around the hippocampus. The results provide convincing evidence that entorhinal cortical layer structures can be visualized in vivo using T2*-weighted MRI at 7T.

2220. In Vivo Investigation of Cortical Layers in Area V1 by High Resolution MR Imaging Ana-Maria Oros-Peusquens1, Sandro Romanzetti1, N. Jon Shah1, Robert Turner2 1Institute of Medicine, Research Centre Juelich, Juelich, Germany; 2Max-Planck-Institute for Human Cognitive and Brain Sciences, Leipzig, Germany

We present a method which provides reliable 3D characterisation of Gennari’s stripe in vivo, using an affordable amount of measurement time at a widely available field strength of 3T. Images of six volunteers (4 male and 2 female, mean age 32 years) were acquired using a magnetisation-prepared 3D TSE sequence with nearly isotropic resolution of 0.4x0.4x0.5mm3. Between 3 and 5 separate volumes are reconstructed for each volunteer and averaged off-line. Besides optimisation of the white-grey matter contrast with the magnetisation prepared TSE, coregistration, complex averaging and parallel imaging turn out to be very important in the detection of myelination patterns in vivo

2221. Assessing Spatial Correspondence Between Subtle Cortical Dysplasias and Sulcal Pattern Pierre Besson1, Andrea Bernasconi1 1McGill University, Montreal, Canada

We examined the spatial correspondence between small focal cortical dysplasia (FCD) and sulci on MRI in 43 patients. 21/43 (48%) patients had small FCD. 18/21 (86%) FCD had been overlooked. Sulci were identified automatically and visualized with FCD in 3D. We measured the depth of the sulci related to FCD and corresponding sulci in 21 controls. 18/21 (86 %) small FCD were located at the bottom of a sulcus. Sulci related to FCD were 23% deeper than in controls. Small FCD are located at the bottom of a deep sulcus. Sulcal morphology should be scrutinized when evaluating epileptics with FCD.

Poster Sessions

370

2222. Quantitative Histological Validation of Fiber Orientation Distributions Based on High-Angular Resolution Diffusion Imaging Nate White1, Trygve B. Leergaard2, Ingeborg Bolstad2, Jan G. Bjaalie2, Helen D’Arceuil3, Alex de Crespigny3, 4, Anders Martin Dale5, 6

Novel diffusion-based magnetic resonance imaging techniques are increasingly applied to measure multi-directional tissue architecture. Although these methods are promising, there is a need for validation against measurements derived directly from the underlying tissue. We here compare standard diffusion tensor estimates and high-angular resolution diffusion-MRI derived fiber orientation distributions (FODs) against “gold standard” histologically-derived FODs of myelinated fibers in fixed rat brain tissue. In regions with unidirectional myeloarchitecture, both methods correlate well with average histological measurements. In regions with in-plane crossing myeloarchitecture, DT estimates correlate poorly, while the high-angular diffusion-based FOD estimates yield average correlations above 85%. 1University of California, San Diego, USA; 2University of Oslo, Norway; 3Massachusetts General Hospital, Harvard Medical School, USA; 4Oxford University, UK; 5UCSD, La Jolla, California , USA; 6Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA

2223. Optimized In-Vivo High-Resolution Monkey DTI in Practice Xiaoxu Liu1, Jianhui Zhong1 1University of Rochester, Rochester, New York, USA

DTI coupled with fiber tracking provides a unique tool to study the brain structure and function non-invasively. Non-human primate brain plays important roles in the related studies but fixed brains are often used. In this study, an optimized in-vivo high-resolution monkey DTI scan procedure was proposed and the impact of scan resolution on fiber tracking was analyzed. Using the proposed protocol, we are able to derive the diffusion tensor and track the fiber at relatively high spatial resolution with the DTI data acquired in an acceptable scan time. It is important to collect the real high-resolution data instead of interpolation for accurate tensor calculation and fiber tracking.

2224. T1, T2, and ADC of the Rat Retina at 7T Govind Nair1, Qinag Shen1, Timothy Q. Duong1 1Emory University, Atlanta, Georgia, USA

The retina is about 200-300 μm thick, posing a significant challenge for MRI applications. Nonetheless, the highly structured retina with well-defined and multiple layers provides an excellent model to test high-resolution anatomical, physiological and functional MRI techniques. With increasing interests in using MRI to study the thin retina, knowledge of quantitative T1, T2 and ADC would help to systemically optimize structural, physiological and functional MRI contrasts of the retina. The goal of this study is to quantitatively measure T1, T2 and ADC in the rat retinas at very high spatial resolution.

2225. Super-Resolution in Layer-Specific MRI of the Retina Eric R. Muir1, Timothy Q. Duong1, Govind Nair1 1Emory University, Atlanta, Georgia, USA

Super-resolution (SR) algorithms are post-processing methods that use sets of spatially shifted images to improve spatial resolution. Super-resolution applied in-plane to MRI has been problematic, and the consensus is that little information is added by SR from shifting the field of view. Physical motion of the object being imaged can be used to obtain the spatial shifts for SR MRI, but this technique has not yet been studied. We apply in-plane SR to in vivo MRI of the rat retina to improve layer-specific resolution by utilizing the spontaneously slow drifting movement of the eye to obtain the spatial shifts.

2226. Noninvasive Detection of Retina Degeneration in Mice Using Diffusion MRI at 11.74T Qing Wang1, Junjie Chen, Huiying Zhang, Shiming Chen, Sheng-Kwei Song1 1Washington University, Saint Louis, Missouri, USA

Diffusion weighted images were acquired along three orthogonal directions on the retina in retina degeneration-1 (rd1) and the age matched control mice at 11.74T. Apparent Diffusion Coefficient maps were examined for both rd1 and control mice. The retina thickness of the rd1 mouse was thinner than that of the control due to the degeneration of photoreceptor cells, resulting in a single MR-detected retina layer observed in the rd1 mouse. This layer exhibited significantly higher ADC^ and ADC„U than the corresponding MR-detected inner retina layer of the control mouse. The current findings demonstrate that diffusion MRI can be a noninvasive tool to detect retinal degeneration in mice.

2227. In Vivo Measurements of Ocular Accommodation Eric Frederick1, 2, Kathryn Richdale3, Mirko Hrovat4, Samuel Patz2 1UMass Lowell, Lowell, USA; 2Brigham and Women's Hospital, Boston, Massachusetts, USA; 3Ohio State University, Columbus, Ohio, USA; 4Mirtech Inc, Brockton, Massachusetts, USA

We observed ocular accommodation in vivo with a custom 1" surface coil over a taped eye. The contralateral eye was allowed to fixate on two optical stimuli: eye charts located 22cm away and another at optical infinity. This setup reduced motion artifacts associated with blinking and allowed for accurate measurements of the accommodative structures of the eye. The accommodative changes in the ciliary body ring diameter, equatorial lens diameter, and lens thickness were measured. The mean chord lengths of the ciliary body diameter and lens diameter both decreased when presented with the closer stimulus while the lens thickness increased as expected. Traditional Poster In Vivo Measurements of Ocular Accommodation

2228. Improved Structural MRI of Mouse Brain in Vivo by Combined T1 and T2 Mapping at 9.4 T Lars Kasper1, Jens Frahm1, Thomas Michaelis1, Susann Boretius1 1Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany

Apart from high spatial resolution, a sufficient contrast-to-noise ratio is essential for distinguishing neuronal structures. Here, anatomical details of the cerebellum in healthy adult mice could be resolved by their relaxation characteristics in T1 and T2 maps obtained by high-resolution 3D MRI at 9.4 T. Respective data sets were exploited to improve the distinction of cerebellar white matter from the granular cell layer and molecular layer by combining the information of T1 and T2 maps in a suitably synthesized T1+T2 map.

Poster Sessions

371

2229. Validation of Different MRI Vessel Caliber Index Models with In-Vivo 2-Photon Microscopy Measurements of Vessel Caliber in a U87 Mouse Brain Tumor Model Christian T. Farrar1, Carsten D. Ley2, Walid Kamoun2, Young R. Kim1, Bruce R. Rosen1, Rakesh K. Jain2, A. Gregory Sorensen1 1Massachusetts General Hospital, Charlestown, Massachusetts, USA; 2Massachusetts General Hospital, Boston, Massachusetts, USA

Relative vessel caliber index (rVCI) measurements may provide an important biomarker for assessing tumor angiogenesis. The aim of this study is to validate the MR methods for determining rVCI with in-vivo 2-photon microscopy data in a U87 mouse brain tumor model. In particular, two models for calculating the rVCI from MR measurements of R2* and R2, acquired before and after MION injection, have been proposed: a linear and a 3/2 power model. For the field strength (9.4T) and MION concentration (20 mg/kg) used in this study we find excellent agreement between the 2-photon data and the linear rVCI model.

2230. Venous Detectability with 9.4-T BOLD 3D Microscopy: Comparison with Two-Photon Microscopy Sung-Hong Park1, 2, Kazuto Masamoto2, Iwao Kanno2, Seong-Gi Kim1 1University of Pittsburgh, Pittsburgh, Pennsylvania, USA; 2National Institute of Radiological Sciences, Inage, Japan

Rat brain vasculature was imaged at 9.4 T with blood oxygenation level dependent (BOLD) microscopy without exogenous contrast agent. Quantification in the somatosensory cortex shows a decrease of intracortical venous density with cortical depth, with smaller diameter veins being more numerous in shallow regions, while larger diameter veins drain the deeper cortical regions. Since venous diameters are not directly quantifiable by BOLD, we also measured diameter dependent intracortical venous density by in vivo two photon microscopy. Density comparisons between the two modalities show that veins as small as 15 µm diameter are detectable with 9.4 T BOLD microscopy under our imaging conditions.

2231. Angiography and Venography in a Single SWI Acquisition Samuel Barnes1, Elena Manova1, E. Mark Haacke1 1Wayne State University, Detroit, Michigan, USA

We demonstrate that it is possible to collect the entire vasculature of the brain, both arteries and veins, in a single scan using an SWI sequence with a contrast agent or with MTC.

2232. Investigation of Caffeine's Impact on Cerebral Physiology Using SWI (Susceptibility-Weighted-Imaging) Katharina Helm1, Jan Sedlacik1, Alexander Rauscher2, Hans-Joachim Mentzel1, Jürgen R. Reichenbach1 1Friedrich Schiller Universität, Jena, Germany; 2UBC MRI Research Center, Vancouver, Canada

Caffeine enhances the BOLD (blood oxygenation level dependency) signal change by acting as an adenosine antagonist and thus changing the cerebral blood flow. Recent study has shown that caffeine has a contrast enhancing effect on cerebral veins using SWI. Aim of this study was to investigate moment and dimension of maximal signal change comparing caffeine-inured and -abstinent volunteers.

2233. Microangiography of the Primate Brain at 7 Tesla Using USPIO Particles Myriam Marianne Chaumeil1, 2, Christopher Wiggins1, Valdis Gudmundsdottir1, Jean-Sebastien Raynaud3, Eric Giacomini1, Yoann Buvat1, philippe hantraye2, vincent lebon1, gaelle louin3 1NeuroSpin, Gif-Sur-Yvette, France; 2MIRCen, Fontenay-aux-Roses, France; 3Guerbet, Roissy CDG, France

Utrasmall SuperParamagnetic Iron Oxide (USPIO) particles were used to perform microangiography of the primate brain on a clinical 7 Tesla system. Cumulated doses of 5/15/45/135ìmol/kg were injected and the relationship between dose and contrast was evaluated qualitatively. Microvasculature was shown to be clearly visible at a 45ìmol/kg dose of USPIO, giving potential way for applications of this technique in humans.

2234. High-Resolution Contrast-Enhanced Magnetic Resonance Angiography of the Mouse Circle-Of-Willis Ketan B. Ghaghada1, 2, Gabriel Philip Howles, 12, Yi Qi1, G A. Johnson1, Srinivasan Mukundan1 1Duke University Medical Center, Durham, North Carolina, USA; 2Duke University, Durham, North Carolina, USA

In clinical practice, magnetic resonance angiography (MRA) is a valuable tool for non-invasively evaluating neurovascular pathology. In the laboratory, transgenic mouse models for these diseases are available; however, translation of MRA techniques for use with MR microscopy has been limited by spatial resolution and signal-to-noise. In this work we use a surface-conjugated Gadolinium liposomal blood pool contrast agent to achieve adequate signal-to-noise to facilitate high-resolution (50x50x100 µm3) MRA of the mouse brain. Images generated at this resolution are able to demonstrate anatomic detail in the mouse that begins to approach anatomic detail seen in clinical MRA of humans.

2235. Physiological Component in Background Flow Velocity in MR Phase Contrast Measurements Stefan K. Piechnik1, Peter Jezzard2, James V. Byrne2, Paul E. Summers2, 3 1Oxford University , Oxford, UK; 2Oxford University, Oxford, UK; 3University of Modena, Modena, Italy

We constructed a simple model to investigate the partial volume of phase encoded velocity components in a large reference region as typical in background correction of MR phase contrast images. We demonstrate that perfect nulling of velocity components from microvascular pools should be treated as an exceptional coincidence of factors, rather than the general case. Even though the magnitude of the effect shown in simulation and experimental data is well under 1mm/s it may affect the measurements of slow flowing compartments, such as CSF.

2236. In Vivo Characterization of White Matter Microvasculature Anisotropy with Diffusion-Weighted MRI Dimitrios C. Karampinos1, 2, Bradley P. Sutton1, John G. Georgiadis1 1University of Illinois at Urbana-Champaign, Urbana, Illinois, USA

Cerebral microvasculature is generally thought as being isotropic and totally random. However, there are areas in brain parenchyma where the local network of the microvessels has a preferential orientation, typically aligned with the neural tracts. The aim of the current study is to use of low b-value Diffusion-Weighted Imaging regime to characterize in vivo the cerebral white matter microvasculature anisotropy. Extending the IntraVoxel Incoherent Motion (IVIM) technique, we extract direction-sensitive Cerebral Blood Volume values which are consistent with the DTI results for the orientation of neural tracts.

Poster Sessions

372

2237. Brain Morphology and Vascular Patterning Analysis in Gli2-KO Mutant Mice Using Contrast Enhanced Micro-MRI Cesar Augusto Berrios-Otero1, Youssef Zaim Wadghiri, Alexandra Joyner2, Daniel H. Turnbull1 1Skirball Institute of Biomolecular Medicine, NYU School of Medicine, New York, USA; 2Memorial SloanKettering Cancer Center, New York, USA

Vascular cell proliferation and patterning is critical for normal embryonic development and also underlies many disease processes such as tumor angiogenesis. In the current study, we use 3D micro-MRI to analyze brain defects in Gli2 mutant mice, which have previously been shown to have midbrain and cerebellum defects. Furthermore the Gli gene family have been implicated as transducers in the Hedgehog signaling pathway and thought to act upstream of VEGF and Notch pathways, which are important mediators of vascular development. Therefore, we also used contrast-enhanced 3D micro-MRI to analyze the cerebral vasculature of the Gli2 mutants and wild type littermates.

2238. MRI Study in Rat to Evaluate the Effect of Cyclooxygenase Inhibition on Blood Brain Barrier Disruption Following Intracerebral Injection of Tumor Necrosis Factor-[alpha] Saeid Taheri1, Eduardo Candelario-Jalil1, Eduardo Estrada1, Gary Rosenberg1, Rohit Sood1 1University of New Mexico, Albuquerque, New Mexico, USA

Recombinant human Tumor Necrosis Factor (rhTNF-Ą) is elevated in a variety of neuropathologies including multiple sclerosis and HIV encephalitis. In the context of ischemic stroke, several studies indicate that rhTNF-Ą is involved in BBB disruption and the initiation of inflammation in the brain. There is increasing evidence that cyclooxygenase (COX-1 and 2 isoforms) inhibition limits BBB disruption following ischemic stroke but the mechanisms involved are unknown. In this study, an MRI technique for estimating barrier permeability coefficient, based on a graphical analysis method has been used for investigating the effect of inhibition of COX-1 and 2 isoforms by indomethacin on BBB permeability in a well characterized animal model of rhTNF-Ą induced BBB disruption. The results suggest that MRI based permeability quantification technique would be a useful non-invasive tool to study and investigate the effect of pro-inflammatory cytokines on BBB damage and test the sensitivity of BB blocking effect of drugs.

2239. Oxygenation-Dependent 9.4-T BOLD 3D Microscopy Sung-Hong Park1, 2, Seong-Gi Kim1 1University of Pittsburgh, Pittsburgh, Pennsylvania, USA

Blood oxygenation level dependent (BOLD) microscopy was performed for rat brain at 9.4 T with three different levels of inspired oxygen (30, 21, and 15%). The results confirmed that the hypointense pixels in the images were indeed of venous origin, and not magnetic susceptibility effects from sources other than venous dHb (e.g., arterial dHb, iron deposits, air/tissue/bone interfaces). When the systemic arterial oxygen saturation level was ~85%, BOLD microscopy revealed additional intracortical vessels presumed to be arteries. According to previous vascular histology, diameters of these intracortical artery-like vessels range 30-50 µm, in agreement with our computer simulations.

2240. Cortical Thickness Measurements as a Function of Choice of T1-Weighted Volume Rysia Burmicz1, A. Simone Reinders, Paula Dazzan, Andrew Simmons1 1Institute of Psychiatry, Camberwell, UK

The impact on cortical thickness measures of using a range of different 3D T1-weighted volumes at 1.5T has been investigated with the aim of determining the sensitivity of these measures to acquisition parameters. Across the different volumes small systematic variations in whole brain cortical thickness measurements were found but data was found to be reasonably consistent. The mean thicknesses of cortical lobes varied consistently across volumes with the exception of the temporal lobes. This may be indicative of the challenges of isolating this region of cortical ribbon.

2241. Multi-Parameter Mapping of the Human Brain at 1mm Resolution in Less Than 20 Minutes Nikolaus Weiskopf1, Gunther Helms2 1University College London, London, UK; 2Goettingen University, Goettingen, Germany

A 3D FLASH-based protocol was designed for the human brain to obtain maps of T1, T2*, PD and MT at 1 mm resolution in less than 20 minutes. Spatial distortions were limited by acquisition of multiple gradient echoes with high receiver bandwidth; the associated loss of SNR was compensated by averaging the echoes. MT-maps provided high contrast between GM, WM and CSF without spatial bias and excellent delineation of basal cortical structures. T2*-maps identified iron-containing structures and vessels. Both promise to improve the segmentation of brain structures.

2242. High-Resolution Cross-Relaxation Imaging of the Rat Brain at 3.0T Hunter R. Underhill1, Chun Yuan1, Vasily L. Yarnykh1 1University of Washington, Seattle, USA

We sought to determine the feasibility of capturing the in vivo white matter fiber tracts of the rat brain using cross-relaxation MRI at 3.0T. Pulsed Z-spectroscopic data with variable offset frequencies of the off-resonance saturation pulse were acquired with a 3D spoiled GRE pulse sequence. Through a constrained matrix model of pulsed magnetization transfer, we produced k- and f-maps of the in vivo rat brain. These quantitative maps yielded high-quality anatomic detail, which enabled the visualization of distinct white matter fiber tracts. This study provides compelling evidence for using this technique in translational research involving rat models of human disease.

2243. Detection of the Myelin Water Fraction in 4 Tesla Longitudinal Relaxation Data by Cross-Regularized Inverse Laplace Transform Christian Labadie1, 2, Jing-Huei Lee3, Silvia Jarchow4, William D. Rooney5, Charles S. Springer5, Harald E. Möller1 1Max Planck Institute for Human Cognitive and Brain Science, Leipzig, Germany; 2University of Leipzig, Leipzig, Germany; 3University of Cincinnati, Cincinnati, USA; 4University of Münster, Münster, Germany; 5Oregon Health and Science University, Portland, USA

The multiexponential analysis of normal brain 1H2O inversion recovery data, geometrically sampled starting at ca. 40 ms, reveals the presence of a small relaxographic peak at T1 = ca. 200 ms. This corresponds to 0.12 fraction of the total white matter water signal. It is attributed to the myelin water fraction (MWF), and suggests that water exchange in the human brain is sufficiently slow to enable the observation of water compartmentalization in longitudinal relaxation. In gray matter, the MWF represents ca. 0.05 of its total water and the peak is positioned at the same T1 value as in white matter.

Poster Sessions

373

2244. Measuring Cerebral Metabolism of Oxygen with Multimodal MRI and Near-Infrared Spectroscopy Qiong Zhang1, 2, Ying Wu, 1, Ursula Tuor1, Dave Kirk, 1, Foniok Tadeusz, Kumud Deka, MIchael Smith1, Jeff Dunn, 1 1University of Calgary, Calgary, Canada

Cerebral metabolic rate of oxygen (CMRO2) is the measurement of O2 which is consumed in the brain by metabolic processes and is an important indicator of brain function. A non-invasive novel means of accurately measuring CMRO2, using a multimodality MR and near-infrared spectroscopy system, was presented in this study.

2245. Reproducibility of GABA Quantification in the Brain and the Difference of GABA Concentration by Female Genital Cycle Measured by MEGA-PRESS Using Clinical 3T MRI Apparatus Masafumi Harada1, Hitoshi Kubo, Naomi Morita, Hiromu Nishitani, Tsuyoshi Matsuda 1University of Tokushima, Tokushima city, Japan

The purposes of this study are to evaluate reproducibility of GABA values measured by MEGA-PRESS at a clinical 3T machine and differences of GABA by female genital cycle depending on the brain locations. The reproducibility of GABA was considered to be acceptable under the clinical measurement because the ICC was more than 0.7. Though the GABA concentrations in the follicular state were statistically different depending on the brain location, this regional difference became ambiguous in the luteal state. The GABA concentration in the normal brain would be different depending on the location and influential by the female genital cycle.

2246. 3D Inhomogeneity Correction for MRI Brian Coe1, Douglas P. Munoz1, Olivier Salvado2 1Queens University, Kingson, Canada; 2e-Health Research Centre - CSIRO, Brisbane, Australia

High field magnetic resonance imaging (MRI) can give us beautiful images of the brain but even the best images suffer from intensity inhomogeneity. Neuroscientists face the difficult problem of correcting for intensity inhomogeneity when identifying white matter from grey matter. This delineation is required to mathematically flatten or inflate the cortex for further analysis. Here we present an improved 3D version of a local entropy minimization technique which deals with both local (tissue susceptibility) and global (receiver coil sensitivity) inhomogeneity issues. This new technique also corrects for intersubject variability to assist with an automated grey matter/white matter segmention.

2247. 3T MRI of Patients with a Vagus Nerve Stimulator: Initial Experience Under Controlled Conditions Robert E. Watson Jr. 1, Matt A. Bernstein1, Krzysztof R. Gorny1 1Mayo Clinic, Rochester, Minnesota, USA

Initial experience of scanning 9 patients with an implanted vagal nerve stimulator (VNS) at 3T is described. All exams were performed with a transmit/receive head coil. Average head SAR, as calculated and displayed by the scanner, was kept below 1.3 W/kg as monitored by an MRI physicist. The VNS was turned off, the patients were instructed to use the squeeze-ball alarm at the onset of heating or any other discomfort. Patient well-being was monitored further by intercom communication between all imaging series. Although no patient discomfort or adverse event was reported, extreme caution should be exercised when generalizing this experience.

MRI/MRS of Psychiatric Disease Hall D Thursday 13:30-15:30

2248. Learning Potential in Schizoprenia is Related to Neuronal Integrity of the Anterior Cingulate Cortex as Measured by Proton MR Spectroscopy Harald Kugel1, Jochen Bauer1, Ansgar Siegmund1, Anette Kersting1, Volker Arolt1, Thomas Suslow1, Walter Heindel1, Anya Pedersen1, Patricia Ohrmann1 1University of Muenster, Muenster, Germany

Impairment in cognitive domains has been described in patients with schizophrenia. In this study learning potential was assessed in 35 schizophrenic patients and 23 healthy controls using a dynamic version of the Wisconsin Card Sorting Test (WCST). Cognitive performance was related to cerebral metabolites measured with single voxel proton MRS of the dorsolateral prefrontal cortex (DLPFC) and the anterior cingulate cortex (ACC). In schizophrenic patients a positive correlation between learning potential and NAA levels of the ACC, whereas in healthy controls a correlation between learning and NAA levels of the DLPFC was observed.

2249. Functional MRI of Choice Reaction Time in Chronic Schizophrenia and First-Degree Relatives David Paul McAllindon1, 2, Alan H. Wilman1, Scot E. Purdon1, 2, Philip G. Tibbo1, 2 1University of Alberta, Edmonton, Canada; 2Bebensee Schizophrenia Research Unit, Edmonton, Canada

Slower and more variable reaction time may be a specific cognitive deficit of schizophrenia. This study examines differences in brain activations between healthy volunteers, men with chronic schizophrenia, and first-degree relatives of a person with schizophrenia while the subject performs a visual 2-choice reaction time task.

2250. Glutamatergic Changes in First Episode Schizophrenia After Long Term Assessment Naoko Aoyama1, 2, Jean Theberge1, 3, Dick J. Drost1, Richard WJ Neufeld1, Rahul Manchanda1, Maria Densmore2, Betsy Schaefer1, Peter C. Williamson1 1University of Western Ontario, London, Canada; 2Lawson Health Research Institute, London, Canada; 3, St. Joseph’s Health Care, London, Canada

Schizophrenia is a life long disease with an unknown cause and mechanism. One possible explanation is the glutamate hypothesis, which suggests that decreased NMDA receptor increases glutamate leading to neuronal toxicity. A five year longitudinal proton MRS study on never treated schizophrenics has found a significant decrease in NAA, glutamate, and creatine between 10 months and 60 months after beginning treatment in the left Thalamus. The changes in both NAA and glutamate between 10M and 60M correlated inversely with the length of illness. These results may indicate the neuronal degeneration occurs early in schizophrenia.

Poster Sessions

374

2251. Withdrawn

2252. Joint Source Based Morphometry to Identify Sources of Gray Matter and White Matter Relative Differences in Schizophrenia Versus Controls Lai Xu1, 2, Godfrey Pearlson3, 4, Vince D. Calhoun1, 2 1The MIND institute, Albuquerque, New Mexico, USA; 2The University of New Mexico, Albuquerque, New Mexico, USA; 3Olin Neuropsychiatry Research Center, Institute of Living, Hartford, USA; 4Yale University School of Medicine, New Haven, USA

In this study, we use a novel approach, joint source based morphometry (jSBM), to identify the joint sources networks of gray matter and white matter to reveal differences between schizophrenia patients and healthy controls. JSBM is a multivariate approach for image fusion among different types of structural MRI images. Our approach provides a way to jointly identify changes in both gray and white matter and may prove to be a useful tool to study the brain.

2253. Cortical Glutamate is Linked to Reward Related Ventral Striate Activity – a Study Combining FMRI and MRS at 3 T Florian Schubert1, Ruediger Bruehl1, Frank Seifert1, Jan Reuter2, Martin Voss2, Theresa Dembler2, Nicola Klein2, Yehonala Gudlowski2, Corinna Pehrs2, Juergen Gallinat2, Andreas Heinz2 1Physikalisch-Technische Bundesanstalt, Berlin, Germany; 2Charite Universitätsmedizin, Berlin, Germany

Processing of rewarding stimuli increases firing rate of dopamine neurons in the ventral striatum (VS), which is disturbed in diseases with dysfunctional reward behavior, eg schizophrenia. Interactions between dopamine and glutamate (Glu) may play an important role in reward processing. We examined VS activity (BOLD contrast during reward processing) and Glu in the anterior cingulate (AC) in healthy subjects at 3T in combined fMRI-MRS experiments. VS activation was negatively correlated with AC Glu concentration. Our findings indicate a relationship between frontal glutamate and activation of the ventral striatum and thus indirectly visualize an interaction of dopaminergic and glutamatergic neurotransmission.

2254. Interhemispheric Connectivity in Schizophrenia and Bipolar I Disorder: A Probabilistic Tractography Study Christopher A. Chaddock1, Gareth J. Barker1, Robin M. Murray1, Colm McDonald2 1Institute of Psychiatry, London, UK; 2National University of Ireland, Galway, Ireland

Background: A single cortical area has not been identified that can explain the wide range in symptoms identified in psychotic disorders, therefore a hodological approach, which investigates the pathways that link major cortical and subcortical structures may prove more beneficial. Method: Interhemispheric connectivity was assessed in schizophrenia and bipolar disorder using probabilistic tractography. Results: Significantly reduced FA was detected in the splenium of corpus callosum (but not genu) within the core of the tract in bipolar disorder patients. No significant reductions of FA were detected in schizophrenia. Conclusion: Abnormalities in white matter coherence may be greater in bipolar disorder than schizophrenia.

2255. Schizophrenia But Not Bipolar Adolescent Offspring Show Developmentally Mediated Deficits in Prefrontal Structure and Function Dhruman Goradia1, Diana Mermon1, Debra Montrose1, Boris Birmaher1, Matcheri Keshavan, 12, Vaibhav Diwadkar, 12 1Western Psychiatric Institute and Clinic, Pittsburgh, Pennsylvania, USA; 2Wayne State University, Detroit, Michigan, USA

We hypothesized that relative to controls (HC), schizophrenia (HRS) but not bipolar offspring would show developmentally related deficits in prefrontal structure and function. Region of interest, voxel based analyses of frontal lobe on three age and gender matched groups HC, HRS and HRB with intra-group median splits by age were performed. Spatial working memory addressed frontal lobe function. Only the HRS group showed greater decreases in gray matter density in older adolescents. Corresponding significant decrements in spatial working memory were noted. Results are consistent with exaggerated gray matter pruning in schizophrenia and suggest vulnerability of the frontal cortex in risk for schizophrenia.

2256. fMRI Guided 31P Spectroscopy in Bipolar Disorder Wen-Jang Chu1, 2, Martin Lamy1, James Eliassen1, Xin Wang1, Stephen Strakowski1, JingHuei Lee1 1Univ. of Cincinnati, Cincinnati, USA

The combined approach of fMRI and 31P spectroscopy is proposed to study bipolar disorder patients. A novel behavioral task, Balloon Analogue Risk Task, was used for fMRI study to identify brain regions associated with behavior impairments. Three-dimension 31P MRSI data were used to measure brain chemistry in the brain regions vulnerable to risk taking. Our preliminary result showed that PCr/ATP ratio in the cerebellar vermis of bipolar patients decreased as compared with healthy subjects. However, other regions such as the anterior cingulate cortex, left/right inferior frontal gyrus, left/right thalamus showed hyperactivity in fMRI but no significantly abnormal in 31P metabolites.

2257. Tract-Based Spatial Statistics (TBSS) of Diffusion Tensor Imaging Data in Bipolar Disorder:Abnormalities of the Neurocircuitry Ping-Hong Yeh1, Serap Monkul-Nery, Mark A. Nicoletti, Fabiano G. Nery, Giovana B. Zunta-Soares, John Li, Jack Lancaster, Jair C. Soares 1University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA

Microstructural abnormalities of neurocircuitry in unmedicated bipolar disorder (BD), characterized by low fractional anisotropy in bodies and genu of corpus callosum, anterior cingulum, superior corona radiata and anterior limb of internal capsule, were demonstrated by using tract-based spatial statistics (TBSS) of diffusion tensor imaging data. These findings provide direct evidence of compromised integrity of the inter-hemispheric connections, fronto-limbic and cortico-striatal circuits in BD. These abnormalities could be partially responsible for deficiencies in executive functions, behavioral regulation and impulse control commonly described in BD.

Poster Sessions

375

2258. Quantitative FA Analysis Based on VBM and Probabilistic Tractography Connectivity Between Treatment-Resistant Patients and Treatment-Responsive Patients with Major Depressive Disorder Wu Li1, George Andrew James1, Helen S. Mayberg2, Xiaoping Hu1 1Georgia Tech and Emory University, Atlanta, USA; 2Emory University School of Medicine, Atlanta, USA

Treatment-resistant depression is a severely disabling disorder. Up to 20% of depression patients fail to respond to standard interventions. To study microstructual alterations of cerebral white matter between treatment-resistant and treatment-responsive depression patients, we proposed an approach that quantifies fractional anisotropy changes between these two groups based on VBM and probabilistic tractography connectivity using diffusion tensor imaging. Results indicate treatment-resistant patients have less diffusivity and fiber integrity in thalamus and subgenual anterior cingulate regions than treatment-responsive patients. This robust finding may aid future studies of microstructural changes associated with clinical severity, as well as aid future diagnosis or treatment.

2259. Resting State FMRI in Geriatric Depression Before and After Treatment Minjie Wu1, Robert Tamburo1, Meryl Butters1, Charles F. Reynolds, III1, Howard J. Aizenstein1 1University of Pittsburgh, Pittsburgh, Pennsylvania, USA

The low-frequency (0.01-0.1 Hz) fluctuations in BOLD signal at resting-state have been hypothesized to reveal the baseline of brain activity. In this study, we compared the default-mode functional connectivity in elderly healthy controls, elderly patients with late life depression (LLD), and patients after antidepressant treatment of LLD. Our results show the default-mode functional connectivity of patients with LLD is significantly lower than that of elderly controls in the prefrontal cortex region for a corrected p < 0.05 and there is no statistically significant differences between the patients after treatment and patients before treatment or between patients after treatment and controls.

2260. White Matter Changes in Obsessive-Compulsive Disorder Revealed by Diffusion Tensor Imaging Ivanei Edson Bramati1, Leonardo F. Fontenelle, 12, Jorge Moll1, Ricardo de Oliveira-Souza1, 3, Fernanda Tovar-Moll1 1LABS-D'Or Hospital Network, Rio de Janeiro, Brazil; 2Institute of Psychiatry - Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; 3Gaffree e Guinle University Hospital, Rio de Janeiro, Brazil

Previous studies addressing the involvement of the white matter (WM) tracts in obsessive-compulsive disorder (OCD) have shown contradictory findings. This study applied diffusion tensor imaging to investigate WM changes in patients with OCD, as compared to healthy volunteers. Whole brain, tract-based spatial statistic and a priori selected regions of interest showed decreased fractional anisotropy and increased diffusivity in regions of the internal capsule and tracts of the limbic system. These findings are in accordance to previous studies and also point to the possible involvement of additional WM structures in OCD.

2261. Emotional Arousal and Regulation in Adolescents Prenatally Exposed to Cocaine: An FMRI Study Priya Santhanam1, Zhihao Li1, Claire Coles1, Mary Ellen Lynch1, Stephan Hamann1, Xiaoping Hu1 1Emory University, Atlanta, Georgia, USA

Prenatal cocaine exposure (PCE) causes disrupted emotional arousal regulation. In this study, emotional network activity and emotion regulation during a working memory task were examined in PCE adolescents using fMRI. Several regions of an emotional network were found to have higher baseline functional connectivity with the right amygdala in PCE subjects. Also, a higher memory load during task led to reduced amygdala activity in controls but not in PCE. Results suggest that the emotional network in PCE subjects is more active in the resting state and high activity level continues even with increased cognitive demand, possibly causing impaired attentional control.

2262. Prenatal Cocaine Exposure Alters Default Mode Brain Activity: Functional and Resting State MRI Evidence Zhihao Li1, Priya Santhanam1, Claire D. Coles2, Mary Ellen Lynch2, Stephan Hamann2, Xiaoping Hu1 1Emory Univ./Georgia Tech., Atlanta, Georgia, USA; 2Emory Univ., Atlanta, Georgia, USA

Prenatal cocaine exposure alters the "default mode" brain network activity, which may be part of the neurobiological basis of the teratogenic effect.

2263. Functional Connectivity of Alexithymia in Heroin Addicts chunming Xie1, 2, chunming Xie3, guohua Bi1, guangxiong Liu1, liping Fu1, yongcong Shao1, jun Xie2, wenjun Li2, zhilin Wu2, lin Ma4, zheng Yang1, shi-jiang Li2 1Beijing Institute of Basic Medical Science, Beijing, People's Republic of China; 2Medical College of Wisconsin, Milwaukee, USA; 3Medical College of Southeast University, Nanjing, People's Republic of China; 4Department of Radiology, PLA Hospital, Beijing, People's Republic of China

Alexithymic individuals have difficulty in recognizing and describing emotions. Although recent neuropsychological and neuroimaging data have addressed the fundamental role of the amygdala in mediating emotion in different diseases, such as depression, schizophrenia, and cocaine abuse,to the best of our knowledge, the neural processing of an alexithymic response in heroin-dependents has not been examined. To this end, we utilized resting-state functional connectivity MRI to determine changes in functional connectivity and investigate the neural basis of the alexithymia in heroin addicts

2264. Impaired Decision-Making in Abstinent Methamphetamine Addicts: Iowa Gambling Task Jae-Jun Lee1, Hui-jin Song1, Joo-hyun Kim1, Seung-Tae Woo1, Hee-Kyung Kim1, Ji-Ae Park1, Hui-joong Lee, Yang-Tae Kim2, Yongmin Chang1 1Kyungpook National University, Daegu, Republic of Korea; 2Bugok National hospital, Republic of Korea

Substance dependent individuals (SDI) are characterized by repeated substance use and loss of control, despite the presence of negative consequences. This study assessed temporal response of neural activation in healthy subject and substance dependent individuals (SDI) using the BOLD functional magnetic resonance imaging (fMRI) and Iowa Gambling task(IGT). The results of normal subject showed the activity in right dorsolateral prefrontal cortex (DLPFC) and the right medial superior frontal cortex during ambiguous decision-making Risky decision making on the other hand was more associated with activity in right orbitofrontal cortex (OFC), ventromedial anterior cingulated cortex (ACC), and cerebellum. Compared to normal subjects, SDI failed to activate ventromedial cortex and DLPFC. These differences of frontal activation area were accompanied by an increased susceptibility to the influence of immediately preceding trial outcome.

Poster Sessions

376

2265. Brain Glutamate and Empathy. a Proton MRS Study at 3 Tesla Florian Schubert1, Frank Seifert1, Christiane Montag2, Jürgen Gallinat2, Andreas Heinz2 1Physikalisch-Technische Bundesanstalt, Berlin, Germany; 2Charite Universitätsmedizin, Berlin, Germany

Empathy is an essential element of human behavior. Dysfunctions of empathy and mentalizing have been seen as a basal feature of psychopathological syndromes in severe mental disorders. We investigated the relationship between self-rated dimensions of empathy as measured by the Interpersonal Reactivity Index, and concentrations of cerebral glutamate determined by 1H-MRS at 3 Tesla in 17 healthy subjects. Glutamate concentration in the dorsolateral prefrontal cortex was predicted by empathy factor 'perspective taking'. DLPFC glutamate level and 'perspective taking' score showed a significant negative correlation. These data suggest a possible involvement of cerebral glutamate in cognitive empathy.

2266. Clinical Application of Low-Power 13C MRS Suited to Neuropsychiatric and Frontal Brain Disorders N. Sailasuta1, A L. Gropman2, L. Robertson3, K. Harris1, P. S. Allen4, B. Ross1 1Huntington Medical Resrearch Institutes, Pasadena, California , USA; 2Children's National Medical Center, USA; 3Spin Dynamics, South Pasadena, California , USA; 4University of Alberta, Edmonton, Canada

Neuropsychiatric disorders can be studied with 13C MR spectroscopy only if the regions of brain implicated fall into those distant from the eyes, This has skewed MR research in these important diseases, because proton decoupling power exceeds SAR. New sequence solves this problem - as shown in this Abstract.

2267. White Matter Abnormalities in Tardive Dyskinia: A Diffusion Tensor Image Study Kun-Hsien Chou1, I-Yun Chen2, Pin-Yi Chiang3, Ya-Mei Bai4, Tung-Ping Su4, Woei-Chyn Chu1, Ching-Po Lin2, 3 1Institute of Biomedical Engineering, National Yang-Ming University, Taipei, Taiwan; 2Institute of Neuroscience, National Yang-Ming University, Taipei, Taiwan; 3Institute of Biomedical Imaging and Radiological Sciences, Taipei, Taiwan; 4Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan

Tardive dyskinesia (TD), the most severe side effect of antipsychotics, is characterized by late-onset, repetitive involuntary choreiform movement, tics and grimaces of the orofacial muscles, and dyskinesia of the distal limbs. Pervious studies have suggested that schizophrenic patients with TD had an excess of neurodevelopmental disturbance, particularly minor physical anomalies, in association with cognitive dysfunction and abnormalities of cerebral structure. Abnormality of white matter (WM) change with schizophrenia had been found, but no report ever investigated WM abnormality of TD. Here we presented a study on schizophrenia subjects with/without TD and healthy subjects using voxel-based diffusion tensor imaging technique

Imaging Traumatic Brain & Spine Injury Hall D Monday 14:00-16:00

2268. Quantitative T2 But Not Lesion Volume Correlates with Functional Outcome After Traumatic Brain Injury Alejandra Sierra1, Irina Kharatishvili1, Riikka Immonen1, Asla Pitkänen1, Olli Gröhn1 1A. I. Virtanen Institute for Molecular Science, University of Kuopio, Kuopio, Finland

In traumatic brain injury (TBI) model the animal variety is large. The aim of this study was to test if simple MRI measurements correlate with the functional outcomes measured using behavioural tests. Quantitative T2 measurement was correlated with Beam Balance and neuroscore tests. T2 changes were also detected in the hippocampus and correlated with the Morris Water Maze test. These findings suggest that T2 mapping in lesion and hippocampus 3 days after TBI is an indicator of the functional impairment and has potential as a clinical marker for severity of post traumatic tissue damage.

2269. DTI-Tractography to Detect and Quantify Brain Pathways Affected in Traumatic Brain Injury Manbir Singh1, Jeong-Won Jeong1 1University of Southern California, Los Angeles, California , USA

DTI-tractography is ideally suited to detect axonal injury in traumatic brain Injury (TBI) and quantify disruptions along affected pathways. We have conducted a study where FA maps of four TBI subjects were compared individually to those of 10 normal controls in a standard MNI space to reveal injured regions, which were then used as ROIs to sort and quantify normalized tracts from individual subjects. Results show several regions in individual TBI subjects with significantly reduced FA values (p<0.001), but no regions where FA increased in TBI. ROI sorted tracts in MNI space show significant connectivity reduction along several critical pathways.

2270. 3D MRSI of Traumatic Brain Injury Patients at 3T Duan Xu1, 2, Srivathsa Veeraraghavan1, Qian Zhao1, Hana Lee1, Michele R. Meeker1, Ying Lu1, Jamshid Ghajar3, Geoffrey T. Manley1, Daniel B. Vigneron1, 2, Pratik Mukherjee1 1UCSF, San Francisco, California , USA; 2UCSF/UC Berkeley, San Francisco/Berkeley, California , USA; 3Brain Trauma Foundation, New York, New York, USA

With 1.4 millions of Americans suffering from traumatic brain injury, better diagnosis and treatment planning is needed. In this study, 3D MRSI at 3T was performed on moderate-severe and mild TBI patient groups, and on matched control subjects, confirming previous 1.5T MRSI and whole brain NAA analyses of decreased NAA following injury. NAA/CHO ratios were 1.55±0.14, 1.87±0.41, 1.94±0.51 for moderate-severe, mild, and control groups, respectively. However, only the moderate-severe TBI patient group demonstrated a statistically significant difference (P<<0.01) compared to control subjects. In the longitudinal study of the mild TBI patients within 2 weeks, at 1 month and at 1 year, a trend towards decreasing NAA/Cho ratio did not reach statistical significance (P=014).

Poster Sessions

377

2271. Pathophysiological Changes in Pericontusional Tissue Post Traumatic Brain Injury: A Diffusion Tensor Imaging Study Virginia F. Newcombe1, Guy B. Williams1, M G. Abate1, Doris A. Chatfield1, Joanne G. Outtrim1, Sally G. Harding1, Jonathan P. Coles1, Jonathan H. Gillard1, Peter J. Huchinson1, John D. Pickard1, T Adrian Carpenter1, David K. Menon1 1Cambridge University, Cambridge, UK

Perilesional tissue is a major component of the traumatic penumbra, where physiology is deranged, but clinical interventions may enhance tissue survival. The time course of imaging changes in such target tissue is not well described. We have used diffusion tensor imaging (DTI) to understand temporal changes in pathophysiology around contusions and traumatic intracerebral haematomas, and identify possible biomarkers. This study describes the heterogeneity within lesions and their evolution following acute TBI.

2272. Region of Interest Analysis of DTI FA Histogram Differentiates Mild Traumatic Brain Injury from Controls Zhifeng Kou1, Ramtilak Gattu2, Randall R. Benson2, Naftali Raz2, E Mark Haacke1 1Wayne State University School of Medicine, Detroit, Michigan, USA; 2Wayne State University, Detroit, Michigan, USA

Autopsy data revealed that, in diffuse axonal injury, the corpus callosum (CC), internal capsule, and rostral part of brain stem are major locations of damage. It is still unknown how DTI findings are consistent with reported autopsy data on the regional locations of brain damage. This study is to investigate whether CC is a major location for DTI signal changes after brain injury. Our regional FA histograms of the whole CC and the body of CC showed prominent group differences between MTBI and controls. Our DTI ROI analysis of CC may serve as a hallmarker of mild traumatic brain injury.

2273. Unique Changing Patterns of DTI Parameters Associated with Sport-Related Concussions from Wild Bootstrap Analysis Tong Zhu1, Madalina Tivarus, Jeffray Bazarian, Jianhui Zhong 1University of Rochester, Rochester, New York, USA

Complexities in changing patterns of DTI parameters under sports related concussions as well as the induced mild Traumatic Brian Injury (mTBI) reflect the complex nature of the underlying pathological progress. The mechanical forces during concussions not only cause commonly patterns of axonal injury in vulnerable brain regions but also may result in subject-dependent impact. In this study, we applied a wild bootstrap based analysis in a group of high school hockey and football players to investigate the subject-dependent DTI changing patterns. The spatial locations as well as the levels of DTI changes are shown to be subject-dependent that are not easily detected by the ROI-based or group analysis. Unique patterns of elevated FA and reduced MD under concussion presented in this study is most likely due to the axonal swelling during the process of axonal injury.

2274. Volumetric MRSI of Metabolic Alterations with Traumatic Brain Injury Varanavasi Govindaraju1, Steven F. Falcone1, Jonathan R. Jagid1, Andrew A. Maudsley1 1University of Miami, Miami, Florida, USA

Volumetric 1H MRSI at 3 T has been obtained in subjects with mild and moderate traumatic brain injury. Results indicate significant and widespread alterations of metabolite ratios within all brain regions in comparison to control subjects, with the strongest effect being increased choline/NAA in white matter regions throughout the cerebrum.

2275. Voxel-Based Diffusion Tensor Imaging Study of Mild Traumatic Brain Injury Zili Chu1, 2, Elisabeth A. Wilde3, Stephen R. McCauley3, Jill V. Hunter1, 2, Erin D. Bigler4, 5, Maya Troyanskaya3, Ragini Yallampalli3, Jonathan M. Chia6, Harvey S. Levin3 1Baylor College of Medicine, Houston, USA; 2Texas Children's Hospital, Houston, Texas, USA; 3Baylor College of Medicine and the University of Texas-Houston Medical School, Houston, Texas, USA; 4Brigham Young University, Provo, Utah, USA; 5University of Utah, Utah, USA; 6Philips Medical Systems, Cleveland, Ohio, USA

In many cases, early detection of mild TBI is complicated by unremarkable CT and conventional MRI, despite patient complaints of post-concussion symptoms including memory loss, attention problems and anxiety. This work presents a voxel-based diffusion tensor imaging (DTI) study exploring the underlying structural basis of the somatic, affection and cognitive deficits after MTBI. All injury-affected regions showed marked decreased radial diffusivity despite minimally changed axial diffusivity, consistent with axonal swelling secondary to cytotoxic edema as the probable mechanism of injury. The findings demonstrated the feasibility and potential utility of using DTI as a diagnosis and evaluation tool in acute MTBI.

2276. Diffusion Tensor Imaging Parameters of Apparent Diffusion Coefficient and Fractional Anisotropy in the Evaluation of Traumatic Cervical Spine Injury Sendhil Kumar Cheran1, Kathirkamanathan Shanmuganathan1, Jiachen Zhuo2, Stuart E. Mirvis1, Rao P. Gullapalli2 1University of Maryland Medical Center, Baltimore, Maryland, USA; 2University of Maryland School of Medicine, Baltimore, Maryland, USA

This retrospective study compared DT-MRI parameters of ADC and FA in 11 controls and 50 patients with blunt traumatic cervical spine injury. ADC and FA were measured in the upper, middle, and lower cervical cord regions. Patients were divided into 4 subgroups of expected injury severity and compared to controls. ADC decrease reflects the severity of injury. FA shows significant decrease in the middle and lower cervical spinal cord of all patient groups. ADC and FA changes were found even in the absence of cord contusion by conventional MRI sequences.

2277. Traumatic Extra-Axial Hemorrhage: Correlation of Postmortem MSCT, MRI, and Forensic-Pathological Findings Eva Scheurer1, 2, Javier Anon, Luca Remonda, Adrian Spreng, Gerhard Schroth, Michael Thali1, Kathrin Yen3, Chris Boesch2 1University Bern, Bern, Switzerland; 2University Bern & Inselspital, Bern, Switzerland; 3Medical University Graz, Graz, Austria

Diagnosis of traumatic extra-axial hemorrhage is of paramount importance in forensic investigations of living or dead injured subjects in order to determine the legally relevant evolution of fights and accidents. Imaging techniques are increasingly used in forensic medicine to complement or even replace invasive methods. Thus, the diagnostic accuracy of postmortem multi-slice computed tomography (MSCT) and magnetic resonance imaging (MRI) was retrospectively evaluated using subsequent autopsy as a reference standard. CT and MRI are of comparable potential in forensic medicine as diagnostic tools for traumatic extra-axial hemorrhage in living or dead injured subjects.

Poster Sessions

378

Parkinson's Disease Hall D Tuesday 13:30-15:30

2278. Neurocognitive Mapping in Parkinson’s Disease and Supranuclear Palsy for Sustained Phonation and Phoneme Tasks S Sachin1, Senthil S. Kumaran1, Sumit Singh1, Vinay Goyal1, Garima Shukla1, Madhuri Behari1 1All India Institute of Medical Sciences, New Delhi, India

FMRI was carried out in 22 patients with Parkinson’s disease and 18 with progressive supranuclear palsy with speech dysfunction using sustained phonation and phoneme tasks. Analysis using SPM2 was done for 8 PD, 7 PSP patients and 6 healthy controls. For sustained phonation, superior temporal gyrus was activated in PD patients and occipital cortex in PSP subjects in comparison to controls. For phoneme, PD and PSP patients recruited lingual gyrus obviating the need for more efforts for the task. Increased activation of other areas in PD could be due to failure of the executive fronto-striatal network.

2279. Lack of MRI Evidence for Increased Iron in the Substantia Nigra of PD Brains at 7T Eleanor F. Cox1, Krishna Gontu2, Andrew Peters1, Andreas Schaefer1, Nin Bajaj2, Penny A. Gowland1, Dorothee P. Auer3 1Univerisity of Nottingham, Nottingham, UK; 2Nottingham University Hospital, Nottingham, UK; 3University of Nottingham, Nottingham, UK

We aimed to study effects of increased nigral iron in PD on transverse relaxivity at 7T. 5 PD patients and 5 age matched controls were studied using a GESE sequence. Regional fits for T2, T2* and T2’ failed to show enhanced relaxation in the substantia nigra or elsewhere in PD brains. We found a trend towards increased T2 in the putamen of patients. We assume that additional pathological processes reduce transverse relaxivity, thus effectively offsetting any iron related effect. This would explain previous controversial findings and suggest that iron concentrations cannot be simply inferred from relaxivity measures in diseased tissue.

2280. Initial Study of Parkinson's Disease at 7T: Can Differences Between Parkinson's Patients and Healthy Controls Be Depicted? Brenda Reader Cuson1, Peter Wassenaar1, Karen Thomas1, Atom Sarkar1, Amir Abduljalil1, Michael V. Knopp1, Petra Schmalbrock1 1Ohio State University, Columbus, USA

Control and Parkinson’s disease (PD) subjects were imaged at 7T with an IR-dTFE sequence. T2* from ROIs of the red nucleus, substantia nigra, white matter tract medial to the substantia nigra, putamen, globus pallidus, and caudate were generated to obtain R2* values. In the RN, reduced R2* was found only in PD. For all other brain regions, R2* was similar. Interestingly, we also found that PD 1st echo brain stem images had diminished contrast as compared to controls. Overall, R2* may reflect vasculature rather than brain iron, and diminished contrast of RN in PD could be due to T1 differences.

2281. Brain Atrophy and White Matter Hyperintensities in Early Incident Parkinson Disease. a Large Case-Control Study Turi Olene Dalaker1, 2, Jan Petter Larsen2, Niels Bergsland1, Mona Beyer2, Guido Alves2, Michael G. Dwyer1, Ole-Bjorn Tysnes3, Ralph HB Benedict1, Arpad Kelemen1, Robert Zivadinov1 1State University of New York at Buffalo, Buffalo, New York, USA; 2Stavanger University Hospital, Stavanger, Norway; 3Haukeland University Hospital, Bergen, Norway

We measured the extent of brain atrophy and WMH in a large sample of early Parkinson Disease (PD) patients compared to age-matched NC. There were no significant MRI differences between PD and NC subjects. A novel finding was that a higher WMH load correlated with impaired cognition (measured by the Mini Mental Status Examination, MMSE) in PD, but not in NC. Logistic regression showed that the total volume of WMH was a significant predictor of the MMSE score (ß= -.272, p<0.0001) in early clinical stages of incident PD.

2282. Mild Cognitive Impairment in Early Parkinson Disease is Associated with Posterior Cingulate Atrophy. a Voxel Based Morphometry Study Turi Olene Dalaker1, 2, Robert Zivadinov1, Jan Petter Larsen2, Mona Beyer2, Jennifer Cox1, Guido Alves2, Kolbjorn Bronnick2, Ole-Bjorn Tysnes3, Ronald Antulov1, 4, Dag Aarsland2 1State University of New York at Buffalo, Buffalo, New York, USA; 2Stavanger University Hospital, Stavanger, Norway; 3Haukeland University Hospital, Bergen, Norway; 4Clinical Hospital Centre Rijeka, Rijeka, Croatia

We investigated whether mild cognitive impairment in early, incident Parkinson�s Disease is associated with regional gray matter atrophy. Using white matter lesion-corrected voxel-based morphometry analysis, we found atrophy in the right posterior cingulate (p= 0.054 corrected for multiple comparisons) in MCI patients (n= 21) compared to unimpaired patients (n=22).

2283. MRI Methods at 4.7 T for Imaging Parkinson’s Disease Robert Marc Lebel1, Amir Eissa1, Myrlene Gee1, Marguerite Wieler, Wayne Robert Wayne Martin, Alan H. Wilman1 1University of Alberta, Edmonton, Canada

In this work we consider three techniques for following Parkinson's disease using high field MRI at 4.7 T. The three methods are: extremely high resolution T2-weighted imaging, apparent T2 mapping and susceptibility imaging. Together these three methods provide both superb spatial rsolution and contrast sensitivity to iron in the basal ganglia.

2284. Diffusion Abnormalities in Parkinson's Disease Depend on Clinical Subtype Dorothee Auer1, Krishna Gontu, Gayathiri Sivasubramaniam1, Paul S. Morgan1, Nin Bajaj 1University of Nottingham, Nottingham, UK

The study aims to evaluate the usefulness of diffusion tensor imaging as biomarker of Parkinson’s disease (PD), and to study the effect of clinical subtypes. 21 patients with PD (11 with tremor dominant type [TDPD] and 10 with postural instability gait disorder [PIGD] and 14 controls were studied at 3T. Nigral ADC was significantly elevated in patients and discriminated PIGD from TDPD. Putamenal ADC and FA were significantly increased in patients. Nigral FA and putamenal ADC were moderately associated with clinical severity. DTI at 3T depicts may serve as neurodegeneration marker in PD.

Poster Sessions

379

2285. Parkinsonism Caused by Substantia Nigra Injury Following CO Intoxication: A Quantitative Study by IR Gray Matter Subtraction MR Imaging Cheng-Yu Chen1, 2, Nai-Yu Cho3, Hua-Shan Liu1, 4, Chun-Jen Hsueh1, Hung-Wen Gao1, Ming-Chung Chou4, Chao-Ying Wang1, 4, Hsiao-Wen Chung4, Guo-Shu Huang1 1Tri-Service General Hospital, Taipei, Taiwan; 2National Defense Medical Center, Taipei, Taiwan; 3National Yang-Ming University, Taipei, Taiwan; 4National Taiwan University, Taipei, Taiwan

This study was designed to evaluate the pars compacta (PC) degeneration in carbon-monoxide-induced parkinsonism (COIP) patients using inversion-recovery gray matter suppression (IR-GMS) sequence with a skeleton-based image segmentation program. PC injuries in COIP patients were of significant changes with hyperintensity in middle and lateral segments on IR-GMS imaging as compared to the control group (p<0.05). There was also a general trend of increased degeneration in segment approaching to the lateral parts of PC in our preliminary observations. The novel application with IR-GMS sequence in this study successfully demonstrated its usefulness in allowing a confident differentiation between COIP and normal control groups.

2286. Quantitative Diffusion Tensor Imaging of the Brain Reflects Motor Impairments in a PD Mouse Model with Intraneuronal [alpha]-Synuclein Aggregates Greetje Vanhoutte1, Andy Buys1, Philipp Kahle2, Annemie Van der Linden1 1University of Antwerp, 2020 Antwerp, Belgium; 2Hertie Institute for Clinical Brain Research, University Clinics Tubingen, 72076 Tubingen, Germany

Parkinson’s Disease is a progressive neurodegenerative disorder associated with movement impairments. The neuropathological hallmark of PD is loss of dopaminergic neurons in the substantia nigra and formation of Lewy bodies including á-synuclein. The exact relationship between á-synuclein misfolding and neurodegeneration is still unclear. (Thy1)-h[A30P]áSYN transgenic mice in which the á-synucleinopathy manifests itself as intraneuronal áSYN inclusions were subjected to in-vivo DTI measurements. In accordance with the behavioral deficits we observed alterations in microstructural integrity in the motor circuit reflected as a decrease in FA, ë1 and ë2 for the motor cortex and a decrease in ë1 for the substantia nigra.

Advanced Imaging of the Spine & Spinal Cord Hall D Wednesday 13:30-15:30

2287. Reliability of 1H-MRS of the Cervical Spine at 3T Nashiely Pineda-Alonso1, Michael Benatar2, Robert Smith1, Xiaoping Hu1, John Carew3 1Emory University, Atlanta, USA; 2Emory University. School of Medicine, Atlanta, USA; 3Emory University. School of Public Health, Atlanta, USA

1H-MRS of the spinal cord has been applied to observe the differences between multiple sclerosis patients, spinal tumor patients and healthy subjects, comparing sometimes the concentrations of major metabolites within the spinal cord to other regions of the central nervous system. The purpose of this study was to quantify the intra-subject variability (reliability) of the spectroscopy of the spinal cord at 3T, a useful estimate for determining the detectability of metabolite changes that are measured longitudinally within-subject. Our pooled standard deviation estimates of intra-subject reliability are the first to be reported in the literature.

2288. Altered Spinal Cord and Brainstem Activation in Response to Peripheral Sensitization to Sensory Stimuli: A Spinal FMRI Study Niousha Foad Ghazni1, Cathy M. Cahill1, Caroline F. Pukall1, Natalie Kozyrev1, Patrick W. Stroman1 1Queen's University, Kingston, Canada

To understand how peripheral sensitization affects the nervous system, we must first examine the transmission pathways in the spinal cord and brainstem of healthy individuals. Spinal fMRI studies, using a HASTE sequence, were carried out in 26 healthy individuals. Innocuous and noxious stimuli were applied before and after sensitization using capsaicin. The findings from this study suggest that peripheral sensitization alters what would normally be an innocuous response to that of a painful response, strongly implying pain pathway activation.

2289. Diffusion Tensor Imaging and Quantitative Tractography in Chronic Spinal Cord Injury Benjamin Michael Ellingson1, Shekar N. Kurpad2, John L. Ulmer2, Brian D. Schmit1 1Marquette University, Milwaukee, Wisconsin, USA; 2Medical College of Wisconsin, Milwaukee, Wisconsin, USA

This study focuses on diffusion tensor imaging and quantitative tractography in subjects with chronic spinal cord injury. We observed significant differences in fiber tract density, as well as rostral-caudal asymmetry at the lesion site in subjects with chronic lesions.

2290. 3D Myelin Water Imaging of Cervical Spondylotic Myelopathy at 3T Erin Leigh MacMillan1, Armin Curt1, 2, Burkhard Mädler1, David K B Li1, Marcel F. Dvorak1, 2, Alex L. MacKay1 1University of British Columbia, Vancouver, Canada; 2International Collaboration on Repair Discoveries, Vancouver, Canada

Cervical spondylotic myelopathy (CSM) is characterized by spinal canal narrowing leading to cord damage, however, conventional MRI cannot elucidate the underlying pathological processes. We present a multi-echo T2 relaxation measurement, which resolves the ratio of myelin-associated water to the total water through analysis of the T2 decay curves, providing a myelin water fraction (MWF). This study presents the first MWF determined for spinal cord white matter, and illustrates the promise of T2 relaxation imaging as a tool to investigate pathological changes in spinal cord white matter with a successful application to CSM.

Poster Sessions

380

2291. Longitudinal Dynamic Contrast-Enhanced (DCE-) MRI of Spinal Cord Injury in Mouse Mehmet Bilgen1 1Medical University of South Carolina, Charleston, USA

Spinal cord injury (SCI) disrupts blood spinal cord (SC) barrier (BSCB) permeability, which leads to secondary injuries, resulting in permanent neurological deficits. Recent trend indicates that mouse models are gaining popularity in SCI research, despite that the resulting inflammation response is different than rat. Our goal is to demonstrate the feasibility of performing DCE-MRI of SCI and determine vascular changes to explain why the neuropathology of injured SC in mouse is different. We also provide insights on how to develop pharmacokinetic models to quantify the BSCB permeability and explore surrogate bioimaging markers for assessing the functional status of injured SC.

2292. Neuronal and Vascular Changes in Syringomyelia: Investigations Using Longitudinal MRI Mehmet Bilgen1 1Medical University of South Carolina, Charleston, USA

Syringomyelia is a heterogeneous collection of neuropathological conditions characterized by abnormal fluid-filled cavities (syringes) within spinal cord (SC). This condition develops in significant portion of patient population with spinal cord injury (SCI). The mechanisms causing the formation and enlargement of syringes following SC trauma are complex and still not fully understood. Using longitudinal MRI, the current study aims to show the evolution of neuronal and vascular changes, describe the onset and advancement of syringomyelia and demonstrate how this condition affects the overall structure and function of the injured SC.

2293. Diffusion Weighted SSFSE with Dixon Fat-Water Separation Ken-Pin Hwang1, Jingfei Ma2, Ananth J. Madhuranthakam3, Eric T. Han4, Wei Sun5, Zachary W. Slavens5, David C. Alsop6, 7 1GE Healthcare, Houston, Texas, USA; 2University of Texas M.D. Anderson Cancer Center, Houston, Texas, USA; 3GE Healthcare, Boston, Massachusetts, USA; 4GE Healthcare, Menlo Park, California , USA; 5GE Healthcare, Waukesha, Wisconsin, USA; 6Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA; 7Harvard Medical School, Boston, Massachusetts, USA

High lipid signal in diffusion weighted images could potentially mask lesions near or within fatty tissue. Image-based Dixon methods have demonstrated excellent fat suppression but are not readily compatible with EPI acquisitions. In this work we insert time shifts in a diffusion weighted SSFSE sequence that provides phase information from the start of the echo train. In-phase and out-of-phase images are acquired with this sequence and are passed into a recently developed Dixon algorithm (MEDAL). We demonstrate that undistorted diffusion weighted images with uniform fat suppression can be obtained in challenging areas such as the cervical spine.

2294. Quantitative Assessment of Traumatic Spinal Cord Injury with Diffusion Tensor and Magnetization Transfer MRI Seth A. Smith1, 2, Visar Belegu1, 2, Bennett A. Landman2, BettyAnn A. Chodkowski1, 2, Jonathan A.D. Farrell2, Peter C. van Zijl1, 2, John W. McDonald1, 2 1Kennedy Krieger Institute, Baltimore, Maryland, USA; 2Johns Hopkins University, Baltimore, Maryland, USA

Spinal cord damage contributes to functional deficits in patients with traumatic spinal cord injury (SCI). Clinical and conventional MRI methods may lack specificity for prognosis and identification of the potential for recovery. Thus, a spinal cord MRI protocol that quantitatively examines the tract-specific structural integrity that can be related to function would be beneficial in the clinic. We present a combined diffusion tensor and magnetization approach that shows aberrant metrics in a patient with SCI compared to healthy controls. DTI tractography and column-specific metrics may be particularly useful in revealing the microstructural evolution of SCI in vivo.

2295. IDEAL ASSIST (Automated Spine Survey Iterative Scan Technique): Metastasis Detection Kenneth Lee Weiss1, Rebecca S. Cornelius2, Elyse E. Lower3, Jane L. Weiss4, Dongmei Sun5, Jun Ying6, Bruce W. Mahoney2, Maria I. Altbach7, Mariano Fernandez-Ulloa2 1University of Cincinnati, Cincinnati, Ohio, USA; 2University of Cincinnati, Cincinnati, USA; 3University of Cincinnati, Cincinati, USA; 4WestImage, Cincinnati, USA; 5Jiaotong University, Beijing, People's Republic of China; 6Univeristy of Cincinnati, Cincinnati, USA; 7University of Arizona, Tucson, USA

We prospectively tested IDEAL (Iterative Decomposition of Water and Fat with Echo Asymmetric and Least-squares Estimation) ASSIST (Automated Spine Survey Iterative Scan Technique) in 24 breast cancer patients at 3T. The novel methodology provided high sensitivity, specificity and inter-rater agreement for the detection of spinal metastases, performing better than PET-CT. In all studies, FSE IDEAL provided uniform fat and water separation throughout the entire 70cm FOV. FGRE ASSIST afforded subminute submillimeter in-plane resolution with high contrast between disc and vertebrae in two contiguous breath-hold series. The rapid automated high resolution and contrast MRI technique holds significant promise for metastasis surveillance.

2296. Feasibility of Delayed Anionic Gadolinium Enhancement in the Intervertebral Disc as a Quantitative Measurement of Disc Degeneration Joshua Levitz1, Burkhard Mädler1, Brian Kwon1, David Wilson1 1University of British Columbia, Vancouver, Canada

Delayed gadolinium enhancement of cartilage has been used to identify cartilage degeneration in synovial joints. The same underlying mechanisms of degeneration are present in the intervertebral disc as in cartilage. This study looks at the feasibility of using anionic contrast agent uptake in porcine intervertebral discs, in-vitro, to quantify disc degeneration. T1 maps of healthy and chemically degenerated discs after immersion in anionic contrast agent were created. Degenerated discs showed a greater change in T1 times after contrast agent enhancement compared to healthy specimens, showing this to be a feasible technique.

Poster Sessions

381

2297. Non-Subjective Spatial and Temporal Evolution of Damage Following Spinal Cord Injury: Automated and Semi-Automated Recognition of Affected Areas Observed in Q-Space MR Maps Revital Nossin-Manor1, 2, Yoram Cohen1 1Tel-Aviv University, Tel-Aviv, Israel; 2The Hospital for Sick Children, Toronto, Canada

Quantification of spinal cord damage following trauma is difficult. In the past, we have demonstrated the utility of using high b-value q-space diffusion-weighted MRI to follow the spatial and temporal damage evolution after spinal cord hemi-crush injury. In these studies spinal cords were assigned according to their unilateral trauma severity. The spinal cord were removed and fixed 5 days, 10 days and 6 weeks after hemi-crush and scanned by MRI using heavily diffusion-weighted imaging. Here we preset automated and semi-automated recognition methods to obtain non-subjective spatial and temporal evolution of the damage following spinal cord injury (SCI).

2298. Exploring the Information Content of Q-Space Diffusion Weighted Imaging: Application to Multiple Sclerosis (MS) Spinal Cord Lesions Bennett Allan Landman1, Jonathan Andrew David Farrell1, 2, Seth A. Smith2, 3, Peter A. Calabresi3, Peter C. van Zijl, 23, Jerry L. Prince1 1Johns Hopkins University, Baltimore, Maryland, USA; 2Kennedy Krieger Institute, Baltimore, Maryland, USA; 3Johns Hopkins University School of Medicine, Baltimore, Maryland, USA

Q-space imaging is an emerging analysis technique for diffusion weighted images that shows promise for assessing tissue microstructure. Using a robust analysis method that accounts for image noise characteristics, we investigated q-space MR findings in the in vivo human spinal cord for a control and two patients with multiple sclerosis (MS). The probability density function (PDF) for diffusion showed substantial heterogeneity, which may be indicative of substructure within the white matter and gray matter (e.g., dorsal root collaterals). We present a compact and intuitive visual representation of the information content in the PDF in healthy tissue and in MS lesions.

2299. Direct Imaging of Spinal Cord Axons in Intact Lamprey by Diffusion-Weighted μ-MRI Alexander C. Wright1, Guixin Zhang1, Suzanne L. Wehrli2, Michael E. Selzer1, Felix W. Wehrli1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA; 2Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA

Sea lampreys (Petromyzon marinus) are used to model axonal regeneration following spinal cord injury, since axons in these animals spontaneously regenerate. Recently µ-MRI has been used to image axon tracts in excised lamprey spinal cord, as well as regional differences in diffusion anisotropy. This suggests the possibility of in vivo serial imaging of axonal recovery from injury, provided sufficient SNR and diffusion-weighted contrast can be achieved. As a step toward this goal, we here report direct visualization of spinal cord axons in an intact lamprey by diffusion-weighted µ-MRI.

2300. Sub-Acute DTI Predicts Long-Term Behavioral Outcome in the Mouse Models of Spinal Cord Injury Tsang-Wei Tu1, Joong Hee Kim2, Sheng-Kwei Song2 1Washington University School of Engineering, St. Louis, Missouri, USA; 2Washington University School of Medicine, St. Louis, Missouri, USA

SynopsisCurrently, there is no effective noninvasive method capable of predicting long-term neurological outcome in spinal cord injury (SCI). In this study, we applied the diffusion tensor imaging (DTI) to a mouse model of SCI acutely (~ 3 hrs after injury) and sub-acutely (7 days pst injury) to evaluate the intact (or survived) white matter after SCI. The determination of residual ventrolateral white matter (VLWM) using DTI derived anisotropy index was demonstrated to predict the long-term behavioral outcome of the injured mice. Our results suggest that anisotropy map derived by DTI measurement, specifically sub-acute phase, has potential to estimate non-invasively the extent of the residual VLWM and predict the long-term behavioral outcomes in SCI.

2301. Correlating the Decreased Axial Diffusivity with Morphological Changes After Axonal Injury Tsang-Wei Tu1, Joong Hee Kim2, Mingqiang Xie2, Sheng-Kwei Song2 1Aerospace and Structural Engineering, Washington University School of Engineering, St. Louis, Missouri, USA; 2Washington University School of Medicine, St. Louis, Missouri, USA

SynopsisRecently, Diffusion Tensor Imaging (DTI) has been used to quantify the severity of white matter damage in rodent models of Spinal Cord Injury (SCI). It has been demonstrated that axial diffusivity derived from DTI was a sensitive biomarker of axonal damage in SCI. It is hypothesized that the axonal morphology plays a key role influencing the modulation of axial diffusivity after injury. In this study, the comparison of in vivo DTI and confocal microscopic images were conducted on the Yellow Fluorescent Protein (YFP) mice. Swelling, beading, and fragmentation of YFP+ axons were found in the injured cord paralleling the decreased the axial diffusivity. The present result suggests that the axial diffusivity strongly depends on the morphological changes resulting from the injury to axons.

2302. Brain DTI of Spinal Cord Injured Rats Jaivijay Ramu1, Juan Herrera1, Raymond Grill1, Tobias Bockhorst1, Ponnada Narayana1 1University of Texas, Houston, USA

In order to understand the neural basis for the extensive cortical plasticity seen on fMRI in experimental spinal cord injury, brain DTI and immunohistochemical studies were performed on normal and injured rats. These studies revealed fiber plasticity in the internal capsule and cerebral peduncle. The plasticity includes both strengthening of the connectivity of the existing fibers, as inferred by the increased FA values, and increased number of fibers, as inferred from the tractography and GAP43 expression.

2303. Discrepancies Between DTI Measures and Histology in Spinal Cord and Brain in Experimental Animal Models Juan Jose Herrera1, Jaivijay Ramu1, Alex Li1, Tessy Chacko1, Ponnada A. Narayana1 1Univ. of Texas Health Science Center at Houston, Houston, Texas, USA

Fractional anisotropy (FA), based on diffusion tensor imaging (DTI), provides important information about tissue integrity. The value of FA depends on a number of factors that include degree of myelination and axonal morphometry and thus lacks pathologic specificity. There is some literature, mainly based on animal studies, that the individual diffusivities, longitudinal (?l) and radial (?t) improve pathologic specificity over FA. In this study we performed DTI and histology in both spinal cord and brain in experimental animal models. These studies demonstrate in some instances there is no direct correlation between the individual diffusivities and myelin and neurofilament.

Poster Sessions

382

2304. Actively Decouled Two Coil System Enables in Vivo DTI of Mouse Cervical Spinal Cord at 4.7 T Joong Hee Kim1, Justin Haldar2, Zhi-Pei Liang2, Sheng-Kwei Song1 1Washington University School of Medicine, St. Louis, Missouri, USA; 2University of Illinois at Urbana Champaign, Urbana Champaign, Illinois, USA

In vivo DTI was performed for mouse cervical spinal cord at a 4.7 T magnet. Actively decoupled volume coil (RF excitation) and saddle type surface coil (signal receiver) provided good SNR to perform in vivo DTI within one hour using the conventional spin echo diffusion weighted imaging sequence. The acquired DTI maps revealed anisotropic characteristics of white matter and dorsal gray matter. Also, the coherent, axially elongated axonal fiber tracts can easily be seen with diffusion ellipsoids. The present results showed feasibility of in vivo diffusion observation of mouse cervical spinal cord at 4.7 T with reduced scan time.

MRI of Animal Brain Hall D Thursday 13:30-15:30

2305. MRI Look Locker Estimates of the Longitudinal Relaxation Rate Are Approximately Linear in Contrast Agent Tissue Concentration Ramesh Paudyal1, 2, Hassan Bagher-Ebadian3, Tavarekere N. Nagaraja3, Swayam Panda3, Joseph D. Fenstermacher3, James R. Ewing, 13 1Oakland University, Rochester, Michigan, USA; 2Henry Ford Hospital, Detroit, Michigan, USA; 3Henry Ford Hospital, Detroit, Michigan, USA

We investigate the effect of intra- to extracellular water exchange on a Look-Locker estimate of the tissue longitudinal relaxation rate, R1, when contrast agent (CA) enters the extracellular space. We demonstrate through modeling and experiments in cerebral tumor that Look-Locker estimates of tissue R1 scale approximately linearly with tissue concentration of CA.

2306. Opening the Blood Brain Barrier with Ultrasound for in Vivo Contrast-Enhanced Imaging of the Mouse Brain Gabriel Philip Howles1, 2, Kristin Frinkley1, Yi Qi1, Kathryn Nightingale1, G A. Johnson1 1Duke University, Durham, North Carolina, USA

In vivo MRI of the mouse brain is limited by the long T1 of the brain. T1-shortening contrast agents are excluded from the brain by the blood brain barrier (BBB). We present here a novel technique for BBB Opening with Lipid microspheres and UltraSound (BOLUS). The co-administration of perflutren lipid microspheres and ultrasound opens the BBB both globally and non-invasively. Using this technique, Gd-DTPA can enter the brain, enabling contrast-enhanced imaging in vivo. With contrast enhancement, high-resolution (50x50x100 µm3) T1-weighted brain images can be acquired in less than one hour.

2307. Early Life Stress: Longitudinal Monitoring of Morphological Impact on the Hippocampus Using in Vivo MR-Imaging in Mouse Model Wilfried Reichardt1, Claus Gross2, Inga Herpfer2, Carola Haas2, Klaus Lieb2, Dominik von Elverfeldt1 1University of Freiburg, Freiburg, Germany; 2University Hospital Freiburg, Freiburg, Germany

Early life stress constitutes a risk factor for the development of psychological disorders, such as depression in human. Early life stress was modelled in C57Bl6 mice using a model of unpredictable maternal separation (daily 3h, between post-natal days 1-14). Previous results of our group had shown sex-related differences on RNA- and protein level between the experimental groups, especially at day 15 post partum. We set out to show, that it is possible to detect morphological changes of the hippocampus in an early life stress model in mice using highresolution in vivo MRI.

2308. Hippocampal Anisotropy is Associated with Dendritic Quantity Jason C. Pych1, 2, P N. Vankatasubramanian1, 3, James Faulkner IV1, Alice M. Wyrwicz1, 3 1ENH Research Institute, Evanston, Illinois, USA; 2Northwestern University Weinberg College of Arts and Sciences, Evanston, Illinois, USA; 3Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA

Previous research from our lab found that diffusion tensor imaging-derived fractional anisotropy (DTI-FA) values are lower in the hippocampus of Tg2576 Alzheimer’s Disease mice than in wildtype controls. The present study seeks to understand the structural correlates of hippocampal anisotropy. The hippocampi of mice were characterized via DTI-FA and microscopy at 3 or 5 months of age. Results demonstrated that both FA and the percent of neuropil occupied by dendrites increased from 3 to 5 months of age, supporting the hypothesis that an increase in FA is associated with an increase in the number of dendrites in the hippocampus.

2309. Magnetic Resonance Imaging of Acute Alterations in the Rat Brain Following Simulated Space Radiation Lei Huang1, Anna Smith1, Peter Cummings2, Edward J. Kendall3, Andre Obenaus1 1Loma Linda University School of Medicine, Loma Linda, California , USA; 2University of Virginia, Charlottesville, Virginia , USA; 3Memorial University of Newfoundland, St. John's, Canada

In the rat model of space radiation, we reported here the sensitivity of quantitative MRI in assessment of acute molecular disturbances in brain. At 1 week after whole-brain only 56Fe radiation (0, 1, 2 and 4 Gy) with 6 rats per group, T2WI, DWI and CET1 were performed. In absence of visible abnormalities in the images, quantitative analysis T2WI and DWI revealed the significantly increase in T2 relaxation time and decrease of ADC within hippocampus and entorhinal cortex. Except for the variable astrocytes activation in 4 Gy group, neuropathology was not evident. This approach may be translatable to clinical context.

2310. Investigating the Role of SuFu in Cerebellar Development Matthijs Christiaan van Eede1, Jung-Eun Jinny Kim, Shoshana Spring1, Jason P. Lerch1, Norman Rosenblum2, R M. Henkelman1 1Toronto Centre for Phenogenomics, Toronto, Canada; 2The Hospital for Sick Children, Toronto, Canada

MRI techniques have been increasingly used for phenotyping mouse models. This study has provided proof of principle of the power of MR imaging in the Sufu mutants, resulting in striking visual malformations of the cerebellum.

Poster Sessions

383

2311. Quantitative MRI to Study Ocular Drug Distribution from Sub-Tenons’ Injection Susan S. Lee1, 2, David Z. D'Argenio1, Gevorg Karapetyan2, Ira Harutyunyan2, Hyun Kim2, Rex A. Moats2 1University of Southern California, Los Angeles, California , USA; 2Childrens Hospital Los Angeles, Los Angeles, California , USA

Drug distribution and pharmacokinetics of sub-Tenon's injection were studied with quantitative ocular MRI. Depots of higher viscosity demonstrate longer residency time, and drug from the depot diffused from the sub-Tenon's space into the aqueous humor. This study demonstrates that sub-Tenon's injection of viscous formulations have potential for sustained drug release.

2312. Brain Redox Imaging Using Blood Brain Barrier Permeable Nitroxide MRI Contrast Agent Fuminori Hyodo1, Kai-Hsiang Chuang, Artem G. Goloshevsky, Shingo Matsumoto1, James B. Mitchell1, Alan P. Koretsky, Murali C. Krishna1 1National Cancer Institute/NIH, Bethesda, USA

Reactive oxygen species (ROS) and compromised antioxidant defense may contribute to numerous brain disorders. Nitroxides are nontoxic stable organic free radicals having a single unpaired electron and therefore are capable of providing MRI contrast via shortening the longitudinal relaxation time (T1). In addition, nitroxides exhibit catalytic antioxidant activity. In this study, the ability of a blood brain barrier (BBB) permeable nitroxide, methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl (MC-P), as an MRI contrast agent for brain tissue redox imaging was examined. Furthermore, MC-P relaxation in the rodent brain was quantified by MRI at 4.7 T using a fast Look-Locker (LL) T1 mapping sequence.

Manganese in the Brain: Method & Application Hall D Monday 14:00-16:00

2313. Detection of Olfaction Induced Activation in the Brain After Systemic Manganese Infusion Otto Heikki Henrikki Manninen1, Toni Aittoniemi1, Arto Lipponen1, Heikki Tanila1, Olli Gröhn1 1University of Kuopio, Kuopio, Finland

The aim of this study was to test whether activation dependent MEMRI using systemic Mn adminstration with intact BBB is feasible in the olfactory system. We detected significant differences in T1 between the stimulated and the control groups at the olfactory bulb but not in the olfactory cortex.It appears that activation dependent MEMRI with systemic Mn administration with intact BBB is possible only in specific brain regions that have naturally more permeable blood-brain barrier.

2314. Pharmacological Manganese-Enhanced MRI (PhMEMRI) Without Osmotic Breakdown of the Blood Brain Barrier Alessandro Gozzi1, Adam Schwarz1, Valerio Crestan1, Angelo Bifone1 1GlaxosmithKline Medicine Research Centre, Verona, Italy

The application of MEMRI to pharmacological studies could complement phMRI approaches that measure haemodynamic responses as a surrogate. Although manganese does not readily cross the BBB, we recently observed that continuous infusion of MnCl2 can produce weak but reproducible MEMRI signal increases in rat brain parenchyma. Here we have investigated whether this intrinsic permeability can be exploited to map drug-induced MEMRI signal changes in the brain. Amphetamine challenge elicited a bilateral pattern of MEMRI signal increases consistent with previous haemodynamic and metabolic studies. These data suggest the feasibility of functional MEMRI without the need of invasive procedures to breakdown the BBB.

2315. 3D Statistical Mapping of Odor Induced Differences in Manganese Uptake in the Mouse Olfactory System Waqas Majeed1, Matthew Magnuson1, Kerry Ressler, Mike Davis, Shella Keilholz1 1Georgia Institute of Technology / Emory University, Atlanta, Georgia, USA

In this abstract, we report odor-induced differences in enhancement 42 hours after nasal administration of manganese chloride.

2316. Detection of Thalamocortical Inputs of the Rat Whisker Barrel Field Using Manganese Enhanced MRI Jason Tucciarone1, Alan Koretsky1 1National Institutes of Health, Bethesda, USA

The goal of this work was to determine if neural track tracing using manganese enhanced MRI (MEMRI) can distinguish individual thalamocortical inputs to whisker barrels of the barrel field cortex of the rat. Three to five hours post injection of manganese into the ventral posteriormedial thalamic nucleus revealed a narrow band of layer four enhancement confined to the whisker barrel field cortex. Additionally, the T1 enhancement had a periodic structure consistent with the size and location of whisker barrels. This technique has potential applications to investigate anatomical changes in the whisker barrel cortex during plasticity in individual rodents.

2317. Reproducible Imaging of Rat Corticothalamic Pathway by Using Longitudinal Manganese-Enhanced MRI (L-MEMRI) Guadalupe Soria1, Dirk Wiedermann1, Carles Justicia2, Pedro Ramos-Cabrer3, Mathias Hoehn1 1Max Planck Institute for Neurological Research, Cologne, Germany; 2Institut d'Investigacions Biomediques de Barcelona-Consejo Superior de Investigaciones Cientificas, Barcelona, Spain; 3Hospital Clinico Universitario-Universidad Santiago de Compostela, Santiago de Compostela, Spain

Our objective was to optimize the experimental conditions of MEMRI to study the somatosensory pathway longitudinally, and to provide functional information on rat corticothalamic connectivity in parallel with fMRI. Animals received repetitive MnCl2 injections. Spatiotemporal patterns showed a significant hyperintensity induced by manganese transport in structures related to the somatosensory pathway. Parallel fMRI experiments showed that fMRI studies and longitudinal MEMRI can be performed in the same animals. We demonstrate, for the first time, a reliable and reproducible technique to perform longitudinal MEMRI to study the time-course changes of the corticothalamic connections following stroke in the rat.

Poster Sessions

384

2318. Neural Substrate of Chronic Neuropathic Pain in Mice Revealed by Manganese-Enhanced MRI Chun-Xia Li1, Wen-Ju Pan1, Hao Lei1 1Wuhan Institute of Physics and Mathematics, Chinese Academy of Science, Wuhan, People's Republic of China

Manganese-enhanced magnetic resonance imaging (MEMRI) was used to mapping and assessing brain activation pattern of chronic neuropathic pain induced by the chronic constriction injury (CCI) in waken, free moving mice. The data obtained indicated that chronic neuropathic pain induced by CCI involves not only neural activation of the supraspinal structures participating in pain perception and modulation, but also deactivation of descending antinociceptive system and the reward system.

2319. Optic Nerve Damage of EAE Mice Detected by DTI But Not by MEMRI Shu-Wei Sun1, Sheng-Kwei Song1 1Washington University School of Medicine, St Louis, Missouri, USA

In this study, the feasibility of using MEMRI to detect the optic nerve (ON) damage induced by experimental autoimmune encephalomyelitis (EAE), an animal model for human MS, was evaluated. Since axial and radial diffusivities derived from diffusion tensor imaging (DTI) have been reported to detect ON injury in the EAE mice, these parameters were also measured to compare with MEMRI findings. Our results showed that although axonal and myelin damage was detected by significantly decreased axial and increased radial diffusivities in ON from EAE mice, MEMRI showed no significant difference between EAE and control mice.

2320. Negative MEMRI in Optic Nerve After Transient Retinal Ischemia Shu-Wei Sun1, Matthew D. Budde1, Sheng-Kwei Song1 1Washington University School of Medicine, St Louis, Missouri, USA

In this study, the feasibility of using MEMRI to detect optic nerve damage after transient retinal ischemia was evaluated. The results showed that although intensive Mn2+ accumulated in the vitreous space was noticeable in MEMRI, no passive diffusion of the ion into the intra- and inter-cellular space of visual pathway was observed. Damage manifested as significantly reduced MEMRI enhancement in the optic nerve as well as the decreased axial diffusivity without changes in radial diffusivity derived from DTI. This study demonstrated that the uptake of Mn2+ requires functional neuronal cells (the retinal ganglion cells) and the intact axonal transport system.

2321. Glial Tissue Imaging at Ischemic Legion by MEMRI Using Manganese Oral Administration Yuko Kawai1, Masahiro Umeda1, Yasuharu Watanabe1, Toshihiko Higuchi1, Chuzo Tanaka1 1Meiji University of Oriental Medicine, Kyoto, Japan

We succeeded to detect of brain signal enhancement at the ischemic lesion after oral administration of manganese as drinking water continuously after onset of ischemia. We made the temporary middle cerebral artery occlusion (MCAO) model. After MCAO, we started oral administration of manganese solution. T1-W and DWI were acquired during one month after MCAO using a 4.7T-MRI. The signal enhancement of ischemic region was confirmed in oral administration group. With the method of continuous oral dosage of a little manganese, it was suggested that the manganese was accumulated and changed a signal of the brain.

2322. Utilizing MEMRI to Screen Drug Therapies in Mouse Models: the Effect of an Aβ 1-42 Lowering Drug, R-Flurbiprofen, on Axonal Transport Rates in an Alzheimer's Disease Mouse Model Karen Dell Brown Smith1, Robia G. Pautler1 1Baylor College of Medicine, Houston, USA

R-Flurbiprofen is a non-steroidal anti-inflammatory drug (NSAID) that has been shown to reduce A[beta] 1-42 levels and is currently being employed in clinical trials as a potential therapy for Alzheimer’s Disease (AD). Utilizing MEMRI, we report that treatment of the Tg2576 mouse model AD with R-Flurbiprofen shows marked improvement of previously reported axonal transport deficits. These data implicate A[beta] 1-42 as having a deleterious effect on axonal transport and support the use of MEMRI as a pharmacological screening tool in mouse models.

2323. Variations of Intensity Patterns of Manganese-Labeled Corticospinal Tract with Spinal Levels Mehmet Bilgen1 1Medical University of South Carolina, Charleston, USA

Manganese-enhanced MRI (MEI) offers a novel neuroimaging tool to anterogradely trace corticospinal tract (CST) in live rats and detect axonal fiber connectivity in injured spinal cord (SC). Anatomically, the transverse size and shape of SC as well as its gray matter white matter intensity pattern varies in cervical, thoracic, lumbar and sacral levels. The same is true for the CST. Our goal is to establish baseline intensity patterns of manganese-labeled CST in different levels of SC in normal rat. This normative data would allow detecting any changes due to dysfunctional axonal fibers as a result of SCI or neuropathological alterations.

2324. Signal Enhancement Achieved Through Hypotonic Bath Application of Manganese Chloride in MR Microscopy of the Rat Hippocampal Brain Slice Model Jeremy J. Flint1, Choong H. Lee1, Timmothy M. Shepherd1, Stephen J. Blackband1, 2 1University of Florida, Gainesville, USA; 2Natonal High Magnetic Field Laboratory , Tallahassee, USA

The present study investigates our ability to achieve signal to noise increases and contrast enhancement in the brain-slice model using bath application of hypotonic solutions containing low concentrations of manganese chloride (10μM to 100μM). Manganese concentrations above 10μM elicited significant signal increases compared to control groups. These signal enhancement effects were still present 24 hours following the initial exposure to manganese. Concentrations above 60μM resulted in non-native contrast enhancement of specific hippocampal lamina while concentrations above 100μM resulted in drastic signal loss due to manganese's T2-shortening effects. Future studies will concentrate on optimizing manganese concentration as a function of TR.

Poster Sessions

385

MRS of Animal Brain Hall D Tuesday 13:30-15:30

2325. Regional Metabolite T2 in the Healthy Rhesus Macaque Brain at 7 T Songtao Liu1, Oded Gonen1, Lazar Fleysher1, Roman Fleysher1, Brian J. Soher2, Sarah Pilkenton3, Margaret R. Lentz3, Eva-Maria Ratai3, R Gilberto Gonzalez3 1NYU School of Medicine, New York, New York, USA; 2Duke University Medical Center, Durham, North Carolina, USA; 3Massachusetts General Hospital, Boston, Massachusetts, USA

Non-human primate is an excellent model system for the study of neurological diseases. To correct for unknown T2 weighting in MRS quantification, the T2s of NAA, Cho and Cr in gray and white matter (GM and WM) regions of rhesus macaques were measured at 7T. Data was acquired with 3D multivoxel proton MRSI at 64uL resolution. The results show that the macaques?NAA T2s in GM, 99? ms, (mean ?standard error of the mean) were 10% shorter than that in WM: 111? ms. T2s of Cho, 113? ms and Cr, 99? ms, did not differ between GM and WM.

2326. Regional Variation in the Methyl 1H Signal Intensity of Ethanol in the Non-Human Primate Brain Graham Stallard Flory1, 2, Christopher David Kroenke1, Kathleen A. Grant1, 2 1Oregon Health & Science University, Portland, Oregon, USA; 2Oregon National Primate Research Center, Beaverton, Oregon, USA

In non-human primates, a consistent and reproducible pattern of brain region specific differences in ethanol signal intensity has been observed using multi-voxel NMR spectroscopy. At a TE of 150 ms, the ethanol signal intensity is approximately 30% greater in medial voxels, where CSF concentration is greatest. A similar pattern is observed in water signal intensity and T2. As the CSF contribution to the total ethanol signal intensity is expected to increase with TE, this relationship between ethanol signal intensity and CSF concentration should be considered in designing MRS studies of ethanol in the human brain.

2327. MRS of Orthotopic Mouse Brain Tumors Growing from Directly Implanted Human Tumor Tissue Michael Rosol1, Anat Erdreich-Epstein1, Ignacio Gonzalez-Gomez1, Jonathan L. Finlay1, Marvin D. Nelson1, Mark D. Krieger1, Ashok Panigrahy1, Patrick Reynolds1, Stefan Bluml1, 2 1Childrens Hospital Los Angeles/USC, Los Angeles, California , USA; 2Rudi Schulte Research Institute, Santa Barbara, California , USA

We investigated the in vivo metabolic profiles of untreated brain tumors in humans and of tumors subsequently grown in mice after immediate implantation of tumor cells obtained at the time of surgery. Atypical teratoid/rhabdoid tumor and choroid plexus carcinoma cells were grown in NOD/SCID mice. MR spectra obtained in mice replicated the metabolic patterns of the original tumors.

2328. Metabolic Changes in a Contralateral Hemisphere After Cortex Injury Assessed by 1H MRS. an Animal Study Vít Herynek1, 2, Katerina Ruzicková2, 3, Pavla Jendelová2, 3, Eva Syková2, 3, Milan Hájek1 1Institute for Clinical and Experimental Medicine, Prague, Czech Republic; 2Second Medical Faculty, Charles University, Prague, Czech Republic; 3Institute of Experimental Medicine ASCR, Prague, Czech Republic

Metabolic changes in the brain after an experimental injury of the rat cortex were monitored both in ipsilateral and contralateral hemispheres using proton MR spectroscopy. Decrease of creatine and N-acetyl aspartate concentrations was observed in the lesion, whereas an increase of N-acetyl aspartate and glutamate occurred contralaterally. We hypothesize that uninjured tissue partly substitutes the function of the damaged tissue.

2329. Metabolic Effects of Methamphetamine on the Young Mouse Brain Palamadai Nilakantan Venkatasubramanian1, 2, James Faulkner IV1, Tongyou Ji1, Alice M. Wyrwicz1 1ENH Research Institute, Evanston, Illinois, USA; 2Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA

Methamphetamine abuse in adolescents is a health and social problem in the U.S. Little is known about the effects of this drug on the young brain. We have investigated the behavioral and metabolic effects of different doses and regimens of methamphetamine on the young mouse brain to understand how the drug affects the developing brain. Following methamphetamine administration, behavior was observed. Concentrations of metabolites in the whole brain were measured by high resolution MR spectroscopy on brain extracts.

2330. Adapting Proton Magnetic Resonance Spectroscopy for Non-Invasively Measuring Amine Neurotransmitters and Their Major Metabolites in Vivo Igor Feinstein1, Mary Kritzer, 12, Petar Djuric1, 1, Yao Li1, 1, Mei Yu1, 1, S. David Smith1, 1, Helene Benveniste1, 1 1; 2Stony Brook University, Stony Brook, USA

The studies described involve the development and validation of a novel, non-invasive strategy for measuring amine neurotransmitters in vivo. Although methods like positron emission tomography can provide quantitative neurochemical information, their requirements for radioactive tracers make them unsuitable for use in infants and children. This has left the neurochemistry of the developing human brain virtually unstudied in both health and disease. Our studies in rats indicate that a singular value decomposition approach to positron magnetic resonance spectral analysis can be used to overcome this barrier and provide selective, non-invasive means for measuring neurotransmitter and metabolite levels in the living brain.

2331. Gy Mice Lacking Spermine Show Reduced Taurine in Brain Hippocampus Detected by 1H MRS Xiaojing Wang1, Byeong-Yeul Lee2, Qing X. Yang2, Anthony E. Pegg1 1PennState College of Medicine, Hershey Medical Center, Hershey, Pennsylvania, USA; 2Pennsylvania State Hershey Medical Center, Hershey, Pennsylvania, USA

The polyamines putrescine, spermidine, and spermine are essential for cell growth, differentiation and cell death. The precise roles of polyamines are still unknown. Spermine synthase (SpmS) is 1 of 5 enzymes involved in the synthesis of polyamines from ornithine and methionine. We applied MRS technique to determine the metabolic changes after the SpmS gene is altered in the mouse brain. Our data are the first to demonstrate that the spermine deficiency of Gy mice is correlated with a decrease in taurine. This may be related to the fact that methionine is a precursor for both polyamines and sulfur containing amino acids including taurine.

Poster Sessions

386

2332. 1H MR Spectroscopic Measurement of Neurochemical Alterations in the Hippocampus of a Rat Model of Depression Sung-Tak Hong1, Chi-Bong Choi2, Bo-Young Choe2, Cheongsoo Park3, Gwan Soo Hong3, Jeong-Ho Chae4 1Max Planck Institute for Biological Cybernetics, Tuebingen, Germany; 2The Catholic University of Korea, Seoul, Republic of Korea; 3Korea Basic Science Institute, Ochang, Republic of Korea; 4Saint Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea

The objective of this study is to investigate whether there is an alteration in the level of choline between control animals and rats with depressive characteristics induced by the use of the forced swimming test (FST), an animal model of depression for assessing antidepressant activity. 1H MRS spectra were obtained from both the left and right hippocampus. Rats subjected to the FST showed a significant decrease of the choline/creatine and choline/N-acetylaspartate ratios in the left hippocampus but not in the right hippocampus, an analogue of result in patients with depression.

2333. 13C Spectroscopic Imaging of Glycogen and Metabolites in the Rat Brain Ruud Bernardus van Heeswijk1, Rolf Gruetter1, 2 1Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; 2Universities of Lausanne and Geneva, Switzerland

The Fourier-series window (FSW) spatial localization technique was used in 13C spectroscopic imaging to study glycogen and metabolite distribution in the rat brain after infusion of C1,6-labeled 13C glucose. At a voxel size of 76 μ l we demonstrated good localization for glycogen, glucose, glutamine, glutamate and NAA as well as extracerebral glycerol.

2334. Localized 1H[13C] NMR Measurement of N-Acetyl-Aspartate Turnover in Rat Brain Lijing Xin1, Hanne Frenkel1, Florence D. Morgenthaler1, Vladimír Mlynárik1, Rolf Gruetter1, 2 1Laboratory of Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; 2University of Lausanne and Geneva, Switzerland

In vivo N-acetyl aspartate (NAA) metabolism has been considered to be slow. In the present study NAA turnover was directly measured at very low levels of NAA enrichment using a recently described selective resonance suppression approach to 1H [13C] spectroscopy. NAA turnover in a white/gray matter mixture of rat brain was estimated at 0.24µmol/g h.

2335. Improving the Precision of Brain 13C Metabolic Modeling Using Co-Infusion of [1,2-13C2]acetate and [1,6-13C2]glucose Alexander A. Shestov1, Dinesh K. Deelchand1, Kamil Ugurbil1, Pierre-Gilles Henry1 1University of Minnesota, Minneapolis, Minnesota, USA

Most 13C metabolic modeling studies in the brain have used [1-13C]glucose or [1,6-13C2]glucose as the infused substrate. The goal of the present study was to determine whether the use of alternative substrates (eg acetate) or combination of substrates leads to improved precision on fitted metabolic rates in the model using Monte-Carlo simulations. Results suggest that 13C metabolic modeling using co-infusion of [1,2-13C2]acetate and [1,6-13C2]glucose yields more precise results than either 13C-glucose or 13C-acetate alone.

2336. Rational Design of One-Phase Brain Tissue Extracts for Highly Reproducible 31P MRS of Phospholipids Norbert W. Lutz1, Patrick J. Cozzone1 1Université de la Méditerranée, Marseille, France

Brain lipid extracts are being employed to analyze phospholipid (PL) composition by in vitro 31P MRS. To enable quantitation of a large number of PL classes, several PL solvents have been proposed. However, little attention has been paid to the influence of the other extract components on PL signal separation. We studied chemical shift and LW as a function of sample concentration, and the concentration of chelating agent in the aqueous component of a one-phase solvent system. Thus, we provide essential data for the generation of optimized one-phase extracts for highly reproducible and well-resolved 31P MR spectra of brain PL.

2337. Relayed Magnetization Transfer from Nuclear Overhauser Effects and Chemical Exchanges Observed by the In Vivo31 P MRS in the Rat Brain Fei Du1, Wei Chen1 1University of Minnesota, Minneapolis, Minnesota, USA

The magnetization transfer (MT) effects among NMR resonances of PCr, γ-ATP and Pi have been commonly applied to measure chemical exchange fluxes of the CK and ATPase reactions by saturating γ-ATP resonance. Beside the expected reductions in the Pi and PCr NMR signals upon saturating γ-ATP resonance, one particularly interesting phenomenon, i.e. decreases of signal intensity in α-ATP and β-ATP, was also observed. The underlying mechanism is still not fully understood. The purpose of this study is to identify the possible sources of chemical exchange and NOE which could result in the magnetization reductions of α-ATP and β-ATP when γ-ATP is saturated, and their possible impact on the measurement of chemical exchange rates using the three-site exchange system of PCr←→γATP←→Pi.

Poster Sessions

387

Physiological Characterization in fMR Hall D Wednesday 13:30-15:30

2338. Complex Constant Phase Statistical Model Reduces Venous Contributions to BOLD Cortical Activations in the Visual Cortex Andrew S. Nencka1, Eric S. Paulson1, Daniel B. Rowe1 1Medical College of Wisconsin, Milwaukee, Wisconsin, USA

Dependent upon deoxyhemoglobin concentration, the blood oxygen level dependent (BOLD) signal used in functional MRI is sensitive to both active parenchyma and down-stream draining veins. Some methods have been previously introduced which utilize phase data to identify and discount draining veins in cortical activation computations. In this abstract we consider the phase regressor and complex constant phase statistical methods in data with obvious draining veins to evaluate the efficacy of the statistical methods. In agreement with previous simulations, the constant phase method more robustly biases against draining veins.

2339. Estimating Cerebral Blood Volume with Expanded VASO Slice Coverage Christopher B. Glielmi1, Ronald A. Schuchard2, Xiaoping P. Hu1 1Georgia Institute of Technology / Emory University, Atlanta, Georgia, USA; 2VA Medical Center, Atlanta, Georgia, USA

Recent research efforts have focused on quantifiable complements to blood oxygenation level dependent (BOLD) contrast including cerebral blood flow (CBF) measurement with arterial spin labeling (ASL) and cerebral blood volume (CBV) estimation with vascular space occupancy (VASO). The present work combines simultaneous VASO, CBF and BOLD acquisition with a previous CBV estimation model based on singular VASO acquisition. Furthermore, this work expands this model from a single slice to multiple slice acquisition and models effective blood relaxation to account for the fresh inflow of unsaturated blood, a previous confound of CBV quantification based on VASO contrast.

2340. Partial Volume Effects of CSF and White Matter in Grey Matter Nulled Functional Magnetic Resonance Images Yuji Shen1, Ida Mengyi Pu2, Risto A. Kauppinen3 1University of Birmingham, Birmingham, UK; 2Goldsmiths, University of London, London, UK; 3Dartmouth Medical School, Hanover, USA

We investigated partial volume effects of cerebrospinal fluid (CSF) and white matter (WM) on the recently introduced grey matter nulled (GMN) fMRI. In GMN fMRI, grey matter (GM) signal is suppressed by inversion recovery approach to reveal cerebral blood volume (CBV) change to brain activation. However, residual CSF and WM contributions in the inversion recovery scans will contaminate the desired blood signal, causing the true CBV change being underestimated and overestimated, respectively. Residual CSF is a dominant source of error for CBV estimation with GMN fMRI, giving more than 75% underestimation of true CBV change when CSF fraction > 0.1.

2341. Assessment of Intravascular and Extravascular BOLD Signal with Grey Matter Nulled and VASO FMRI Methods Yuji Shen1, Ida Mengyi Pu2, Risto A. Kauppinen3 1University of Birmingham, Birmingham, UK; 2Goldsmiths, University of London, London, UK; 3Dartmouth Medical School, Hanover, USA

We explored intravascular and extravascular BOLD signals at 3T using grey matter nulled (GMN) and VASO fMRI techniques. Neither GMN nor VASO fMRI showed practical contamination from large draining veins. The activation maps obtained by GMN and VASO fMRI were used to delineate intravascular and extravascular activation regions for the BOLD response. At the spatial resolution of 2x2x5 mm3, the intravascular BOLD signal change is larger than the extravascular one, and the BOLD response outside the CBV increase areas was only 30% of that determined in GMN and VASO positive parenchyma.

2342. Evaluation of Hypercapnic Tasks to Hemodynamically Scale Activation-Induced FMRI-BOLD Signals Nirvish Shah1, Sridhar S. Kannurpatti1, Bharat B. Biswal1 1UMDNJ, Newark, New Jersey, USA

Hemodynamic scaling of fMRI responses reduces BOLD signal variation due to vascular sensitivity. Scaling of fMRI-BOLD response to a neural task is currently carried out using vascular reactivity information usually determined by a hypercapnic task such as breath hold (BH), breathing CO2 or hyperoxia. Hemodynamic scaling is accomplished by simply dividing the task induced response signal with the response obtained during a hypercapnic task. However, the optimal level of hypercapnia obtained either during the BH task or breathing CO2 for hemodynamic scaling is not yet estimated. If the hypercapnic response in a corresponding voxel is greater than the neural-task response in the same voxel, then it has a greater chance to get scaled out (loses significance as a result of scaling). To optimize hemodynamic scaling using hypercapnia tasks such as BH or CO2, we have studied different durations of inspirational BH and breathing various levels of CO2 in healthy young individuals. We have estimated the extent of scaling during each condition on the neural task-induced fMRI-BOLD response.

2343. Effects of Oxygen and Carbon Dioxide on BOLD, CBF, CBV and VSI in Anesthetized Rats Jie Lu1, 2, Guangping Dai, Yasu Egi, Shuning Huang, Eng H Lo, Young Ro Kim 1 Massachusetts General Hospital , Charlestown, Massachusetts, USA; 2Xuanwu Hopital,Capital Medical University, Beijing, People's Republic of China

Cerebrovascular responses during the inhalation of oxygen (O2) and carbon dioxide (CO2) in normal brain tissue are important for investigating exogenous regulation of cerebral hemodynamics. In this study, we characterized various cerebrovascular parameters in response to 100% O2 and 5% CO2 gas inhalation using multiple MRI techniques in rat models. In particular, using both gradient and spin echo- echo planar imaging (GE-EPI and SE-EPI) pulse sequences, we quantified blood oxygenation level dependence (BOLD), cerebral blood flow (CBF), and blood volume (CBV) changes with the use of arterial spin labeling and an intravascular contrast agent.

Poster Sessions

388

2344. Repeatability of a Dual Gradient-Recalled Echo MRI Method to Measure Post-Isometric Contraction Blood Volume and Oxygenation Changes Otto A. Sanchez1, Elizabeth A. Louie1, Bruce M. Damon1 1Vanderbilt University, Nashville, Tennessee, USA

The repeatability of a dual gradient-recalled echo (GRE) MRI sequence that measures change in blood volume and oxygenation in the microvasculature of skeletal muscle is presented. Subjects performed 3 types of isometric dorsiflexion contractions and dual GRE EPI dynamic scans were acquired before, during and after contractions. Signal intensities (δSI) were plotted as a function of time and post-contraction parameters SI, time to half peak and time to peak were determined. Intraclass correlation coefficient was determined to compare the between-day variations. The method is reliable although the repeatability method depends on the parameter evaluated, the muscle, and the TE.

2345. Mapping Hypercapnic Cerebral Vasoreactivity Using Bold FMRI: Regional Variation and Correlations Uma S. Yezhuvath1, Kelly Lewis-Amezcua1, Rani K. Varghese1, Hanzhang Lu1 1UT Southwestern Medical Center, Dallas, USA

BOLD fMRI with 5% CO2 breathing was used to study cerebrovascular reactivity (CVR) in different brain regions in young, healthy controls. Physiological parameters were measured during scan. CVR was computed by regressing measured EtCO2 against BOLD signal. Results indicate heterogeneous vascular reserve across regions (cerebellum had maximal and insula minimal vascular responsiveness). Additionally, we found that regional CVRs are correlated and there appears to be a global factor specific to each person. Based on this, we recommend use of relative CVR instead of absolute CVR in group comparisons. No correlations were found between CVR and measured physiologic parameters or age.

2346. Fast, Calibrated, Quantitative Functional MRI for Single Repeats Using Hyperoxia Daniel Bulte1, Peter Jezzard1 1University of Oxford, Oxford, UK

Increased fractions of inspired oxygen enables the modelling of relative changes in CMRO2, as well as estimating the baseline cerebral blood volume. Subjects were imaged using an interleaved, BOLD/ASL sequence while they performed a 2-level graded motor task followed by two short hyperoxic epochs. These data were used to estimate the theoretical maximal BOLD signal and calculate the relative regional increase in CMRO2 for each task. The hyperoxia BOLD data were also used to produce baseline CBV maps. From the measured relative CBF changes, estimates of quantitative blood volume changes in the motor regions with activation were calculated.

2347. Regional Heterogeneity in Vascular Response to Respiratory Challenges as Measured with BOLD FMRI Molly Gallogly Bright1, 2, Silvina G. Horovitz1, Peter Jezzard2, Jeff H. Duyn1 1National Institutes of Health, Bethesda, Maryland, USA; 2University of Oxford, Oxford, UK

Measurements of regional cerebrovascular reactivity to changes in arterial gas tensions using functional MRI have been shown to accurately indicate pathological abnormalities associated with disease. However, these studies have traditionally focused on the magnitude of the BOLD signal change during prolonged breath-holding or carbogen inspiration. Here we show that simple deep breaths, a task suitable for clinical use, cause transient BOLD signal decreases comparable in magnitude to hypercapnia studies. A new fitting technique using linear optimized basis functions allows for whole-brain voxelwise characterization of both magnitude and relative timing of the cerebrovascular response to the breathing task.

2348. Using 3D GRASE-ASL to Measure Hypercapnic Changes in Cerebral Blood Flow and Arterial Arrival Time Bradley J. MacIntosh1, Kyle TS Pattinson1, Daniel Gallichan1, Imran Ahmad1, Karla L. Miller1, David Feinberg2, Peter Jezzard1 1FMRIB Centre, Oxford, UK; 2Advanced MRI Technologies LLC, Sebastopol, California , USA

Abstract: Adequate Cerebral Blood Flow is necessary to maintain healthy brain tissue. Arterial Spin Labeling is a technique that provides perfusion-weighted images without the use of a contrast agent. ASL can be used to investigate stroke and cerebrovascular disease, but to date there has been only a limited amount of clinical translation. Ideally, we would want our ASL acquisition to produce whole brain quantitation perfusion estimates, in a reasonable length of time (< than 6 minutes). The present study attempts to address these issues, using a hypercapnia model to test the sensitivity of a 3D GRASE-ASL sequence.

2349. Hypercapnia as a Global FMRI Stimulus at 1.5T and 3T: Comparison of Spiral Imaging with Cartesian Parallel EPI Andrea Kassner1, 2, Julien Poublanc3, Jeff Winter2, David Mikulis3, Adrian Crawley3 1University of Toronto, Toronto, Canada; 2The Hospital for Sick Children, Toronto, Canada; 3The Toronto Western Hospital of the UHN, Toronto, Canada

Sensitivity of spiral EPI and cartesian EPI with parallel imaging (ASSET) techniques to susceptibility effects, specifically signal dropout, was quantitatively assessed using hypercapnia as a global BOLD stimulus. Five healthy volunteers were imaged at both 1.5 T and 3.0 T, with both EPI techniques. A significant increase in signal dropout existed for spiral EPI compared with ASSET EPI, however, only at 3.0 T. No differences in the magnitude or variance of the BOLD signal response to hypercapnia existed. Results suggest that using ASSET EPI may improve the quality and interpretation of functional MRI in regions of susceptibility differences.

Poster Sessions

389

fMRI: Mechanisms Hall D Thursday 13:30-15:30

2350. Plausibility of Delayed Arteriolar Compliance as Cause of the BOLD Post-Stimulus Undershoot in Presence of Post-Stimulus Elevation in CMRO2: The Arterial Balloon Model Benedikt Andreas Poser1, 2, David Gordon Norris1, 2 1Radboud University, Nijmegen, Netherlands; 2University Duisburg-Essen, Essen, Germany

There is converging MR and optical imaging evidence suggesting the BOLD post-stimulus undershoot is caused by sustained oxygen metabolism, and that activation related CBV changes occur in the arterial/arteriolar compartment. Under the hypothesis that capillary/venous CBV and CBF rapidly and simultaneously return to base after the stimulus but CMRO2 remains elevated, a sharp transition into the undershoot would ensue. As this is typically not observed there must be a mechanism counteracting rapid accumulation of deoxyhemoglobin in the capillaries. We propose, and in simulations show plausible, that delayed arterial compliance (‘arterial ballooning’) can cause the observed temporal characteristics of the undershoot.

2351. A Multicompartment Vascular Model for Multimodal Analysis Theodore J. Huppert1, Solomon G. Diamond2, David A. Boas3 1University of Pttsburgh, Pittsburgh, Pennsylvania, USA; 2Dartmouth College, USA; 3Massachusetts General Hospital, USA

We describe a dynamic multi-compartment Windkessel model for combining multimodal flow, BOLD, and optical measurements.

2352. Quantification of Vessel Contribution to BOLD Nonlinearity Nanyin Zhang1, Xiao-Hong Zhu1, Wei Chen1 1University of Minnesota, Minneapolis, Minnesota, USA

We have demonstrated that the source of BOLD nonlinearity can completely originate from vascular origin. To further investigate which component(s) inside the vascular tree (capillary or venous vessel) has dominant contributions, we divided all activated pixels in ROI into two groups: in one group, all voxels primarily contain microvasculature; in the other group, voxels are biased by large vessels. By removing all the activated pixels located at large vessels, we found BOLD nonlinearity becomes much less significant. This observation suggests that a very large component, if not all, of BOLD refractoriness is attributed to large vessels.

2353. Single-Subject Hemodynamic Refractory Effects in Healthy Volunteers Benedicte Descamps1, Pieter Vandemaele1, Koen Paemeleire1, 2, Luc Leybaert2, Eric Achten1 1Ghent University Hospital, Ghent, Belgium; 2Ghent University, Ghent, Belgium

We propose a method to measure hemodynamic refractory effects in a single subject. With four different conditions and an acquisition time of 45’30”, reducible to 23’15”, non-linearity of the hemodynamic response could be demonstrated within a single subject. Several processing methods are compared. Very short interstimulus intervals tend to show larger differences then longer interstimulus intervals and one should take this into account when using fast event-related designs. Because migraineurs may lack these refractory effects, this measurement method could be used to distinguish them from healthy volunteers.

2354. Stimulus Frequency Dependency of Postive BOLD (PBOLD) and Post Stimulus Undershoot (PSU) Uzay Emrah Emir1, Zubeyir Bayraktaroglu2, Ahmet Sabri Alper3, Ahmet Ademoglu3, Cengizhan Ozturk3, Tamer Demiralp2 1Bogazici University, Istanbul, Turkey; 2Istanbul University, Istanbul, Turkey; 3Bogazici University, Istanbul, Turkey

most of the researches on BOLD transients were studied with input stimulus frequencies up to 30Hz. An interesting question is how BOLD transient components including the PSU change their behavior when stimulated with a finer frequency resolution up to 40 Hz. In this study we focused on PBOLD and PSU responses during to the stimulation frequencies beyond 8Hz and explored the additional local maxima emerging from a stimulation scheme with a finer frequency resolution. The correlation between the PBOLD and PSU across different stimulation frequencies was analyzed to explore the underlying physiological mechanisms of these two transients.

2355. Inflow Effects on Hemodynamic Responses Characterized by Gradient-Echo BOLD Functional MRI Pei-Shan Wei1, Yau-Yau Wai1, 2, Wan-Chun Kuan3, Chih-Mao Huang1, 2, Changwei W. Wu4, Yung-Liang Wan1, 2, Ho-Ling Liu1, 2 1Chang Gung University, Taoyuan, Taiwan; 2Chang Gung Memorial Hospital, Taoyuan, Taiwan; 3National Tsing Hua University, Hsinchu, Taiwan; 4National Taiwan University, Taipei, Taiwan

Inflow effects on the measured BOLD hemodynamic responses (HRs) of visual stimulations were investigated using gradient echo EPI (TR = 1 s, FA = 300, 600 and 900) at 3 T and 1.5 T. Inflow related signal increases were observed only in the 3T results. Comparing the HRs from the 3T results, the 900-FA responses exhibited latencies significantly faster than the 300-FA. The falling times of the 900-FA responses were later than those of the 300-FA, but the differences were not statistically significant. The 900-FA responses demonstrated greater latency variations than the 300-FA when comparing at the same CNR levels.

2356. Spatial and Temporal Characteristics of the FMRI Response to Brief Somatosensory Stimulation in Rats Yoshiyuki Hirano1, Bojana Stefanovic1, George C. Nascimento1, Afonso C. Silva1 1National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA

The BOLD, CBF and CBV hemodynamic response (HDR) to brief somatosensory stimulation was measured in rats. The HDR to a single 333 μ s pulse was easily detectable and it was confined to medially located regions in S1FL. These results suggest that the HDR to extremely brief stimuli will allow for a better understanding of the mechanisms of neurovascular coupling and allow establishment of the ultimately achievable spatial and temporal resolution of functional neuroimaging.

Poster Sessions

390

2357. Effect of Acoustic Imaging Noise and Recent Acoustic History on Auditory FMRI Response Olumide Olulade1, Shuowen Hu1, Greg Tamer, Jr. 1, Joseph Santos1, Wen-Ming Luh, Thomas Talavage1 1Purdue University, West Lafayette, Indiana, USA

A complicating factor in event-related auditory fMRI analysis is Acoustic Imaging Noise (AIN), produced by rapidly switching gradients during echo planar imaging. The presence of AIN alters fMRI detection of auditory stimuli by producing undesired neuronal activations that can mask stimulus-induced responses. Additionally, activation accumulated over multiple stimuli can elevate the baseline, reducing the available dynamic range. To best evaluate responses to auditory stimuli, there is a need to account for the presence of AIN, beginning with an understanding of the extent of memory in the system, herein referred to as the necessary duration of the acoustic time history of an experiment. A first step toward this goal is examination of the dependence of response attenuation on inter-stimulus interval (ISI) and repetition time (TR).

2358. A Comparison of the BOLD Response Between Two High Magnetic Field Strengths: 7.0 and 11.7 Tesla Joerg Ulrich Seehafer1, Andreas Beyrau1, Tracy Deanne Farr1, Pedro Ramos-Cabrer2, Dirk Wiedermann1, Mathias Hoehn1 1Max Planck Institute for Neurological Research, Cologne, Germany; 2Hospital Clínico Universitario de Santiago, Santiago de Compostela, Spain

Our objective was to compare the BOLD response following forepaw stimulation in rats in two horizontal small animal MRI systems: 7.0 Tesla and a new 11.7 Tesla system. Using the same MR-protocol on both systems we show that increased magnetic field strength and SNR do not lead to higher BOLD signal changes in S1 or S2 areas, but to a better detectability of activated pixels. Subsequently, we used a protocol optimized for the higher gradient strength at 11.7 Tesla, which resulted in high-resolution BOLD-EPI images that showed also activation in thalamus, as well as structure of cortical layers.

2359. Correlation of CBV Changes with FMRI and Laser-Doppler Measurements: Implications on CMRO2 Calculation Peter Herman1, 2, Basavaraju Ganganna Sanganahalli1, Fahmeed Hyder1 1Yale University, New Haven, Connecticut, USA

Quantitative mapping of changes in CMRO2 with BOLD calibration require multi-modal MRI measurements of CBF, CBV, and BOLD. CBF measurements are frequently substituted by laser-Doppler measurements while the CBV measurement can be estimated by vascular physiology based models. We found an alternative method to estimate the CBV changes during stimulation using backscattered light intensity signals from the laser-Doppler measurement. We found a strong correlation between the fMRI measured CBV and the optically measured back scattered light intensity. The backscattered intensity signal follows the CBV changes, therefore it can substitute the CBV measurement without any modeling effort to calculate the CMRO2.

Novel fMRI Techniques Hall D Monday 14:00-16:00

2360. A New Real-Time Functional Magnetic Resonance Imaging Method for Neurofeedback Audrey Yu Ching Kuo1, Charles H. Cunningham1, Simon James Graham1 1University of Toronto, Toronto, Canada

As an alternative to commonly used fMRI methods for on-line visual feedback during an fMRI neurofeedback (NF) experiments such as EPI or spiral imaging, an imaging technique is developed that localizes a column of tissue using outer volume suppression and provides multi-echo (ME) acquisition to sample T2* decay in great detail. The advantages of this technique are enhanced BOLD contrast sensitivity by echo summation and reduced data processing time due to reduced data size. These advantages were confirmed by experiment, indicating that the implementation and validation of the prototype ME acquisition technique has favorable features for performing fMRI NF experiments.

2361. Enhanced BOLD Effect in the Mouse Brain with Fast CRAZED Imaging at High Magnetic Fields Johannes Thomas Schneider1, Cornelius Faber1 1University of Wuerzburg, Wuerzburg, Germany

A fast CRAZED sequence detecting the signal from intermolecular multiple-quantum coherences (iMQC) was implemented at 17.6 T to observe the BOLD effect in the mouse brain. Signal readout as echo train employing a four-step phase cycle for the refocusing pulses and an intensity-ordered k-space sampling allowed for acquisition of CRAZED images in 30 seconds. In the CRAZED images the BOLD effect was more pronounced than in RARE images but smaller than in gradient echo images. Combination of iMQC with T2*-effects may provide larger signal changes than conventional BOLD methods.

2362. Efficient High Resolution FMRI at 7T Anders Nordell1, Samantha Holdsworth2, Rexford Newbould2, Roland Bammer2, Stefan Skare2 1Karolinska University Hospital, Stockholm, Sweden; 2Stanford University, Palo Alto, California , USA

In this work we perform a high resolution fMRI experiment at 7T using a gradient echo Short Axis propeller readout EPI (SAP-EPI) sequence. GRAPPA accelerated SAP-EPI is much less susceptible to image distortion than conventional single shot EPI and has further properties that enable high resolution while maintaining good temporal resolution and volume coverage. The echo time was chosen sufficiently long so that the bulk of the BOLD response originated from extravascular tissue.

2363. Increased Specifity in Functional Magnetic Resonance Imaging from Vessel-Size Estimates Thies H. Jochimsen1, Harald E. Moeller1 1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany

A general problem with the BOLD contrast is its inability to properly localize the region of activity. Rather, the contrast reflects changes in blood oxygenation which can be distant from the activated site, e.g. in the presence of large veins. In this work, the approach of vessel-size imaging was employed using deoxygenated hemoglobin as the contrast agent to increase the specifity of the BOLD contrast. This was achieved by classifying activated voxels according to their microstructure, i.e. the average vessel radius, in order to filter out voxels which contain predominantly large vessels.

Poster Sessions

391

2364. Optimized Acquisition of Susceptibility Weighted Imaging (SWI) at 7T Andreas Deistung1, Alexander Rauscher2, Jan Sedlacik1, Jürgen R. Reichenbach1 1Hospital of the Friedrich Schiller-University, Jena, Germany; 2UBC MRI Research Centre, Vancouver, Canada

Since the relaxation times of blood and brain tissues at 7T are very different from the values obtained at lower field strengths a linear relationship between SWI contrast, echo time (TE) and field strength cannot be assumed. To determine the optimum echo time for SWI at 7T we simulated the complex signal decay of venous vessels in the subvoxel regime as well as the contrast to WM for different aspect ratios (slice thickness : inplane resolution) and blood volume fractions. The simulation and in vivo measurements revealed an optimum SWI contrast for TE≈14ms with voxel aspect ratios larger than 2.

2365. Integration of Generalized Series and Parallel Imaging (GS-Parallel) for High-Resolution FMRI Sungdae Yun1, Sung Suk Oh1, Yeji Han1, HyunWook Park1 1Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea

BOLD fMRI is a technique to study brain function, which requires a high spatiotemporal resolution. To satisfy this requirement, the EPI has been widely used. While the resolution of EPI is sufficient for most fMRI, it is inadequate for studying brain function at the millimeter level. With the EPI technique, it is very difficult to increase the resolution of the fMRI data due to the T2* decay. In this study, we propose a high spatiotemporal resolution MRI technique that combines the parallel MRI and the generalized series techniques with the conventional gradient-echo sequence for fMRI at high magnetic fields.

2366. fMRI with 16 Fold Reduction Using Multibanded Multislice Sampling Steen Moeller1, Eddie Auerbach1, Pierre-Francois van de Moortele1, Gregor Adriany1, Kamil Ugurbil1, 2 1University of Minnesota, Minneapolis, Minnesota, USA; 2Max Planck Institute for Biological Cybernetics, Tubingen, Germany

Multiband multislice acquisition with a 16 channel head coil at 7Tesla is investigated for parallel imaging performance and reconstructions using both GRAPPA and SENSE. With GE-EPI, functional MRI studies with 16 fold reduction, and maximal aliasing of 12 is demonstrated for combined visual and motor studies.

2367. Single-Shot Echo-Volumar Imaging Using Highly Parallel Detection Thomas Witzel1, 2, Jonathan R. Polimeni2, Graham C. Wiggins2, FaHsuan Lin, 23, Stephan Biber4, Michael Hamm5, Ravi Seethamraju5, Lawrence L. Wald2 1Harvard-MIT Division of Health Sciences and Technology, Cambridge, Massachusetts, USA; 2Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, USA; 3National Taiwan University, Taipei, Taiwan; 4Siemens Medical Solutions AG, Erlangen, Germany; 5Siemens Medical Solutions Inc., Malvern, Pennsylvania, USA

Volumetric imaging holds intrinsic sensitivity advantages. FMRI, however, benefits from single-shot acquisition, which reduces the influence of physiologic noise and head motion. Single-shot Echo-Volumar Imaging (EVI) has been proposed to address these issues, but requires excessive amounts of encoding for conventional spatial resolutions. We address this by using high acceleration in the two phase encoding directions made possible by a 32-channel receive coil array. We demonstrate highly-accelerated single-shot EVI with functional studies at 1.5 T. Although susceptibility distortions are larger than those in EPI, the single-shot 3D technique promises increased SNR, vastly improved temporal resolution, and more benign motion effects.

2368. Parallel Imaging Accelerated Multi-Echo FMRI at 7T Heiko Schmiedeskamp1, Rexford David Newbould1, Roland Bammer1 1Stanford University, Stanford, California , USA

At 7T, EPI suffers from severe image distortions due to off-resonance effects. This is particularly critical for fMRI experiments, where accurate localization of functional activation is desired. Image distortions can be reduced using parallel imaging to R-times undersample k-space, therefore reducing the echo spacing in phase-encoding direction and shorten the EPI readout. The loss in SNR from parallel imaging can be compensated by the acquisition of multiple echo images per excitation pulse. Consequently, parallel imaging leads to greatly reduced image distortions at 7T, while maintaining SNR by multi-echo acquisitions.

2369. Distortion Free, BOLD-Contrast FMRI Using a K-T Accelerated Spin-Echo Based Approach at 7 Tesla Jane Frances Utting1, 2, Uwe Heinrichs1, Sebastian Kozerke2, Roger Luechinger2, Ralph Schnitker1, René Vohn1, Thoralf Niendorf1 1RWTH-Aachen, Aachen, Germany; 2University and ETH Zuerich, Zuerich, Switzerland

In order to maximally exploit the advantages of ultra high magnetic fields for BOLD - fMRI without suffering the gross geometric distortion and signal drop-out intrinsic to echo planar imaging, k-t accelerated displaced UFLARE was performed at 7 Tesla. Activation induced signal changes were measured and mapped, using a functional motor paradigm in normal subjects with and without k-t BLAST factors 2, 5, 8 and 16. The sensitivity to BOLD contrast of k-t accelerated displaced UFLARE is shown to be comparable to that of EPI, promising possibilities such as high resolution fMRI with freely selectable T2 or T2* weighting.

2370. Distortion-Free FMRI in the Orbitofrontal Cortex Using RASER Ute Goerke1, Ryan Chamberlain1, Essa Yacoub1, Michael Garwood1, Kamil Ugurbil1, 2 1Radiology/University of Minnesota Medical School, Minneapolis, USA; 2Max-Planck-Institute for Biological Cybernetics, Tuebingen, Germany

In fMRI with conventional gradient-echo (GE) EPI, macroscopic magnetic field variations near air-filled cavities result in signal loss and geometric distortions in the images. T2-weighted sequences mitigate such problems. In this paper, a novel T2-weighted sequence, RASER, is applied to fMRI of brain regions, which are challenging to image with GE-EPI. It is demonstrated that activation in the orbitofrontal cortex is fully recovered using RASER.

Poster Sessions

392

2371. Statistical Significance of the BOLD Response Probed by RASER Ute Goerke1, Ryan Chamberlain1, Michael Garwood1, Kamil Ugurbil1, 2 1Radiology/University of Minnesota Medical School, Minneapolis, USA; 2Max-Planck-Institute for Biological Cybernetics, Tuebingen, Germany

T2-weighted fMRI sequences provide advantages with respect to specificity to the site of neuronal activity at ultrahigh magnetic field since they are dominated by signal components originating from the tissue in the capillary bed. However, in conventional implementations, they suffer from inaccurate non-T2 (i.e. T2

*) contributions that arise from EPI which is typically used for spatial encoding. In this paper, it is demonstrated that a novel T2-weighted sequence RASER, which eliminates this complication, is able to detect activation as well as the more conventional spin echo-EPI method although its maximal relative signal change is lower.

2372. BOLD FMRI Using T2* Weighted Selective Parity Single Shot 3D GRASE Imaging Benedikt Andreas Poser1, 2, Matthias Günther3, 4, David Gordon Norris1, 2 1Radboud University, Nijmegen, Netherlands; 2University Duisburg-Essen, Essen, Germany; 3Neurological Clinic, University Hospital Mannheim, University Heidelberg, Germany; 4mediri GmbH, Heidelberg, Germany

A single-shot T2* weighted 3D-GRASE sequence is implemented based on the principles of the recently presented method for selective parity RARE imaging; this removes the CPMG constraint and furthermore reduces the energy deposition by introduction of a variable flip angle scheme. Attractions of the multiply refocused sequence include potentially higher SNR due to 3D excitation, and very high acquisition speed. Initial functional experiments using visual checkerboard stimulation suggest that brain activation can be detected with high BOLD sensitivity.

2373. Sub-Millimeter Single-Shot 3D GRASE with Inner Volume Selection for T2 Weighted FMRI Applications at 7 Tesla David A. Feinberg1, Noam Harel2, Sudhir Ramanna1, Kamil Ugurbil2, Essa Yacoub2 1Advanced MRI Technologies, Sebastopol, California , USA; 2Center for Magnetic Resonance Research, Minneapolis, Minnesota, USA

Sub-millimeter resolution fMRI will facilitate probing the human brain for a better understanding of the functional organization of cerebral cortex. To date, inner-volume segmented 2D SE-EPI has been used for sub-millimeter resolutions at 7T, but limited to single slice acquisitions due to cross-irradiation. A novel sequence, inner volume 3D GRASE is developed for single-shot imaging to obtain multiple slices. Results show 0.5 mm in-plane resolution 3D single-shot fMRI activation maps in human brain similar to 2D maps. The spin echo refocusing minimized less specific large vessel BOLD effects, and enhanced sensitivity to signals from smaller vessels within tissue.

2374. T2 Weighted FMRI Simultaneously Acquired in Two Distinct Areas of the Human Brain at Ultra-High Field Johannes Ritter1, Pierre-Francois Van de Moortele1, Kamil Ugurbil1 1University of Minnesota, CMRR, Minneapolis, Minnesota, USA

In this study, a Slab wise magnetization Preparation for Functional Imaging with a T2 weight (SPIF-T2) [1] is used. Fifteen oblique slices were positioned to go through the visual- as well as the motor-cortex. This technique is used in conjunction with Parallel Imaging (PI) methods with a one-dimensional reduction factor of four, a half-Fourier technique and a sixteen-channel geometrically adjustable (“flex”) volume coil [2] to allow for whole brain coverage while maintaining short acquisition times, necessary to keep Gradient Echo (GE) contributions small. Specific absorption rate (SAR) is reduced by ~4 fold for 15 slices when compared to a standard multi slice Spin Echo (SE) sequence. This makes it possible to use the more accurate Spin Echo (SE) fMRI (see for instance [1],[3],[4]). Robust activation can be seen in both the visual and motor areas of the brain. This technique can now be applied towards cognitive paradigms corresponding to regions of the brain not previously studied at 7T.

2375. Improved BOLD Detection at 3T Using High-Resolution GRAPPA EPI FMRI Dionyssios Mintzopoulos1, 2, Loukas G. Astrakas1, Graham C. Wiggins1, Lawrence L. Wald1, Bruce R. Rosen1, A Aria Tzika1 1Massachusetts General Hospital, Boston, Massachusetts, USA

Parallel-imaging (pMRI) enables whole-brain fMRI at increased resolution. pMRI penalties include reduced image SNR and spatially correlated noise; gains include reduced susceptibility artifacts and improved BOLD from higher spatial resolution at optimal TE. We performed a motor fMRI experiment with GRAPPA EPI (factor 3) and with a no-GRAPPA EPI sequence at lower spatial resolution. Detected BOLD values were consistently and significantly higher using GRAPPA versus the no-GRAPPA sequence. Since high spatial resolution is impossible unless severely limiting the FOV and/or increasing TE beyond the optimal range for BOLD detection, we conclude that GRAPPA fMRI benefits may outweigh its disadvantages.

2376. Monitoring Tissue Volume Fraction and T1 Changes During Brain Activation Using a Look-Locker EPI Sequence Wanyong Shin1, Hong Gu1, Yihong Yang1 1National Institute on Drug Abuse, NIH, Baltimore, Maryland, USA

We have developed an EPI-based Look-Locker sequence running at a steady-state to monitor physiological and biophysical changes during brain activation. Tissue volume fractions (gray matter, white matter, and cerebral spinal fluid) and T1 were measured every 10 sec, during which a block-design visual stimulation paradigm was presented. Following the stimulation, GM fraction was increased and WM fraction was decreased, while CSF fraction remained the same. T1 was decreased during activation. This new method provides a powerful tool for observing signal changes in tissue components, and would help understand and interpretate fMRI signals.

Poster Sessions

393

2377. Turbo Z-Shimmed UNFOLD EPI Gaohong Wu1, Shi-Jiang Li1 1Medical College of Wisconsin, Milwaukee, USA

Susceptibility differences around the air/bone-tissue boundaries in the human brain induce static field inhomogeneities and result in two major artifacts: image distortion and signal dropout. Most of the studies related to reduction of the susceptibility-induced artifacts attacked one of these two artifacts. An fMRI pulse sequence is proposed to simultaneously reduce both of the artifacts while achieving high spatial coverage with typical imaging parameter settings. The UNFOLD technique and selective z-shim strategy are employed and combined in a framework of the turbo segmented imaging technique. This sequence could be a solution to susceptibility-effect reduction in ultra-high field for fMRI.

2378. Optimizing 3D EPI with K-Space Energy Spectrum Analysis (KESA) Ming-Long Wu1, Larry Panych1, Nan-Kuei Chen2 1Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA; 2Duke University, Durham, North Carolina, USA

In phase-encoded 3D EPI, the k-space energy may shift along the z-direction as a result of local susceptibility field gradients. When the k-space energy is shifted outside of the k-space sampling range, the signal loss artifacts occur. To address this issue, we use the recently developed k-space energy spectrum analysis (KESA) to optimize both acquisition and reconstruction strategies for 3D EPI. The k-space sampling scheme is chosen based on the energy distribution patterns quantified by the KESA. 3D z-shim method is incorporated to further improve the signal-to-noise ratio of the reconstructed 3D EPI.

2379. Asymmetric Spin-Echo Reduces Susceptibility Distortion Without Loss of BOLD CNR Kimberly D. Brewer1, 2, James Rioux1, 2, Xiaowei Song1, Ryan C.N. D'Arcy1, 2, Chris V. Bowen1, 2, Steven D. Beyea1, 2 1National Research Council of Canada, Halifax, Canada; 2Dalhousie University, Halifax, Canada

Recently the Asymmetric Spin-Echo (ASE) Spiral technique has been proposed for overcoming susceptibility induced field gradients (SFG). Using a breath-hold task to elicit whole brain activation, we evaluate the use of this sequence for fMRI. ASE Spiral permits acquisition of up to three spiral images with equivalent R2’-weighting (where R2’ = R2*-R2 and R2 = 1/T2) and k-space filtering (equal to spiral-in). This results in combined images with the reduced image distortion seen in Dual Spiral-In/In, but since all images have matched R2’-weighting, the BOLD CNR is equivalent (or better in regions of SFG) to that of the Dual Spiral-In/Out method.

2380. Single Shot Partial Dual Echo (SPADE) EPI - An Efficient Acquisition Scheme for Whole Brain FMRI Christian Schwarzbauer1, 2, David Porter3 1MRC Cognition and Brain Sciences Unit, Cambridge, UK; 2University of Cambridge, Cambridge, UK; 3Siemens Medical Solutions, Frimley, UK

SPADE is a new acquisition scheme for fMRI based on dual-echo EPI. As in previous work, additional spin-echo EPI images are used to recover signal in regions of susceptibility-related sensitivity losses in the gradient echo images. However, with SPADE the additional spin-echo images are only acquired for the affected slices in the lower part of the brain, reducing the time required to image each volume. This provides an efficient acquisition scheme for fMRI applications where whole brain coverage (and sensitivity) is required. Our preliminary experimental results demonstrate the feasibility of this approach.

2381. Silent Echoplanar Imaging for Auditory FMRI Sebastian Schmitter1, Eugen Diesch2, Michael Amann3, Alexander Kroll1, Maurice Moayer2, Lothar Rudi Schad4 1German Cancer Research Center, Heidelberg, Germany; 2Central Institute of Mental Health, Mannheim, Germany; 3University Hospital of Basel, Switzerland; 4University of Heidelberg, Mannheim, Germany

A new low-noise EPI-sequence is presented that is optimized for auditory fMRI measurements. The sequence produces a narrow-band acoustic frequency spectrum by using a sinusoidal readout echo train, which is adapted to the frequency response function of the MR scanner. Compared to a standard EPI-sequence the acoustic noise reduction amounts up to 20 dBA. Statistical parametric mapping of a simple block-design fMRI experiment with a pure-tone stimulus results in higher levels of significance of auditory activation for the low-noise sequence compared to a standard EPI sequence. These findings strongly suggest that the low-noise sequence generates enhanced BOLD contrasts.

Non-BOLD Contrast Hall D Tuesday 13:30-15:30

2382. Quantification of the BOLD Contrast Mechanism, Including Its Dynamic Approach to Steady State, for Pass-Band Balanced-SSFP FMRI Steve Patterson1, 2, Steven D. Beyea1, Chris V. Bowen1 1Institute for Biodiagnostics (Atlantic), National Research Council , Halifax, Canada; 2 Dalhousie University, Halifax, Canada

A Monte-Carlo simulation was used to quantify the contrast mechanism in pass-band balanced steady state free precession (b-SSFP) fMRI. The simulation permitted susceptibility-induced field offsets, intra-vascular T2 changes, and water self-diffusion effects to be turned on and off in various combinations, quantifying their relative contribution to total BOLD contrast. b-SSFP contrast is dominated by intra-vascular T2 changes at short TR and by susceptibility induced field offsets at long TR. Short TR b-SSFP is preferentially sensitive to oxygenation changes in capillary sized vessels. A strong peak in BOLD CNR was observed before reaching steady state for high flip angle pulses.

2383. A Model for SSFP FMRI Karla L. Miller1, Peter Jezzard1 1Oxford University, Oxford, UK

Steady-state free precession (SSFP) has been proposed for FMRI due to its potential to reduce distortions and signal dropout. It has been demonstrated experimentally that the source of contrast is more complicated than conventional FMRI, and that the contrast can be T2- or T2*-like depending on the imaging parameters. We present a simple but powerful model that describes this complicated behavior, and demonstrate its ability to model data acquired over a wide range of imaging conditions.

Poster Sessions

394

2384. Transition-Band SSFP FMRI with Increased Spatial Coverage: Slice-Dependent Frequency Adjustments in a Bilateral Motor Activation Experiment Pei-Hsin Wu1, Teng-Yi Huang2, Ming-Long Wu3, Hua-Shan Liu1, 4, Hsiao-Wen Chung1, 4, Cheng-Yu Chen4 1National Taiwan University, Taipei, Taiwan; 2National Taiwan University of Science and Technology, Taipei, Taiwan; 3Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA; 4Tri-Service General Hospital, Taipei, Taiwan

Since transition-band balanced steady-state free precession (SSFP) fMRI is sensitive to field inhomogeneity, the narrow sensitivity band would cause sub-optimized functional activation mapping. For bilateral motor fMRI, the wider spatial coverage is particularly important because the functional activation areas in the two cerebral hemispheres are far apart from each other. In our study, we acquire the bilateral motor fMRI by using the slice-dependent frequency adjustment technique to overcome the spatial coverage limitation of SSFP fMRI, such that accurate results at increased functional sensitivity could be obtained.

2385. Improvements in Sweep Scans for Frequency Adjustments in SSFP FMRI Using Coarse Sampling with Cubic Spline Interpolation Pei-Hsin Wu1, Teng-Yi Huang2, Ming-Long Wu3, Hua-Shan Liu1, 4, Hsiao-Wen Chung1, 4, Cheng-Yu Chen4 1National Taiwan University, Taipei, Taiwan; 2National Taiwan University of Science and Technology, Taipei, Taiwan; 3Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA; 4Tri-Service General Hospital, Taipei, Taiwan

The native sensitivity to spatial and temporal field instability is the major problem of transition-band balanced steady-state free precession (SSFP) fMRI. The slice-dependent frequency adjustment technique is a method to potentially overcome the spatial field inhomogeneity. However, fine increment in the SSFP angle is needed for the sweep scan, which prolongs the scan time. In this study, the time of sweep scan is shortened by using a modified processing based on cubic spline interpolation. Results show that the frequency adjustment values could be estimated with sufficient accuracy with 10-fold reduction in sweeping time.

2386. Cortical Depth Dependence and Implications on the Neuronal Specificity of the Functional Apparent Diffusion Coefficient Contrast Trong-Kha Truong1, Allen W. Song1 1Duke University, Durham, North Carolina, USA

A contrast mechanism based on functional changes of the apparent diffusion coefficient (ADC) was previously proposed as an alternative to the blood oxygenation level-dependent (BOLD) contrast to improve the functional localization. Here, we investigate its cortical depth dependence in humans by performing simultaneous high-resolution BOLD and ADC imaging during visual stimulation. Our results indicate that the functional ADC changes are significantly higher in the deep cortical layers than at the cortical surface, whereas the BOLD signal changes are more widespread across the cortex, thus demonstrating the improved spatial specificity of the functional ADC contrast.

2387. Comparison of Diffusion and Hemodynamic Response Functions in Human Visual Cortex Toshihiko Aso1, Shin-ichi Urayama2, Nobukatsu Sawamoto2, Hidenao Fukuyama2, Denis Le Bihan1 1CEA, NeuroSpin, Saclay, France; 2Human Brain Research Center, Kyoto University Graduate School of Medicine, Kyoto, Japan

Neural activation can be detected using heavily diffusion-sensitized MRI (DfMRI). The DfMRI response to a visual stimulation is different from that of BOLD-based fMRI indicating a different signal origin. From the raw signals in the visual areas, we estimated a diffusion response function (DRF) using a pair of gamma density functions under the assumption of a linear time-invariant system and compared it with the BOLD hemodynamic response funciton (HRF). The DRF had a strikingly steeper onset compared to HRF, suggesting a link with a mechanism preceding the vascular response.

2388. Behaviour of Compartmentalized Diffusion-Weighted FMRI Signal from Human Brain During Hypercapnia Daigo Kuroiwa1, Jeff Kershaw2, Yoshiyuki Hirano2, Hiroko Kamada2, Hiroi Nonaka2, Masaya Hirano3, Hiroo Ikehira2, Iwao Kanno2, Takayuki Obata2 1National Institute of Radiological Sciences, Chiba, Japan; 2National Institute of Radiological Sciences, Japan; 3GE Yokogawa Medical Systems, Hino, Japan

Recently, it has been suggested that diffusion-weighted fMRI could provide a more direct method of observing neuronal activity. In this study, signal originated from brain during hypercapnia and visual stimulation diffusion-weighted fMRI experiments was decomposed into intravascular, fast-diffusion phase, and slow-diffusion phase components. It was concluded that the slow-diffusion phase signal change must reflect the neural activation, although the exact mechanism remains unclear.

2389. T1ρ FMRI at 9.4 T: Different Contrasts in the Parenchyma and at the Cortical Surface Tao Jin1, Seong-Gi kim1 1University of Pittsburgh, Pittsburgh, Pennsylvania, USA

We measured the functional response of T1ρ at 9.4 T during cat visual stimulation. It was recently reported that T1ρ increased during activation of human visual cortex at 3 T. This functional elevation of T1ρ was mostly attributed to an increase in cerebral blood volume since the T1ρ of blood water was found to be much longer than that of tissue at 3 T. Our results show a T1ρ increase within the parenchyma and a T1ρ decrease at the cortical surface, indicating spatially different contrast mechanisms.

2390. BOLD FMRI with Magnetization Transfer Effects: Determination of Arterial Blood Volume Change During Neural Stimulation Tae Kim1, Kristy Hendrich1, Seong-Gi Kim1 1University of Pittsburgh, Pittsburgh, Pennsylvania, USA

BOLD fMRI was performed during neural activation in rats at 9.4T with varying levels of magnetization transfer for the purpose of separating intra- and extra-vascular components. Since venous contribution are minimal when TE is long relative to T2, intravascular components represent arterial cerebral blood volume changes (δCBVa). Mean ± SD values of δCBVa were 0.46 ± 0.15 ml/ 100g (n = 13)

Poster Sessions

395

2391. The Effect of Blood Inflow on Vascular-Space-Occupancy (VASO) Contrast Manus Joseph Donahue1, 2, Peter van Zijl1, 2 1The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA; 2The Kennedy Krieger Institute, Baltimore, Maryland, USA

We investigated the effect of inflow of fresh blood-water spins on the signal changes measured using vascular-space-occupancy (VASO) fMRI. VASO contrast is generated using a non-selective inversion, generally employing the scanner’s body coil. We measured VASO signal changes for varying inversion volume thicknesses. The results show that signal changes do not plateau unless the inversion volume has a thickness of at least 500mm and 200mm for TR=2000ms and TR=5000ms, respectively. This is accomplished with most body coils, but care should be taken in quantifying CBF or CBV using VASO when small body coils, or head coils, are used for transmission.

2392. VASO ACDC with Applications to BOLD Calibration Amy Margaret Jane Scouten1, R. Todd Constable1 1Yale University, New Haven, USA

A method is presented for VASO-based calculation of relative CBV change which incorporates both resting CSF fraction, xc,rest, and the change in CSF fraction with activation, δxc. VASO Accounting for Dynamic CSF (ACDC) is applied across the whole brain during a breath-holding task, providing results consistent with gold-standard PET data obtained during hypercapnia. CBV measurements obtained using VASO ACDC are used for calibration of the BOLD signal across the whole brain, offering a promising alternative to calibration using CBF data, the latter of which is limited by complexities associated with the implementation of multi-slice ASL.

2393. Enhanced Sensitivity of Perfusion Imaging to Neuronal Activation Using Turbo Pseudo-Continuous Arterial Spin Labeling (Turbo-PCASL) Hesamoddin Jahanian1, Luis Hernandez-Garcia1 1University of Michigan, Ann Arbor, USA

The recent introduction of pseudo-continuous inversion pulses has greatly facilitated the use of continuous Arterial Spin Labeling (ASL), by compensating for magnetization transfer effects in an efficient manner without using additional hardware [1]. A fast multislice imaging scheme based Turbo-CASL [2] methodology was implemented in order to improve the temporal resolution and sensitivity of pseudo-continuous ASL (pCASL) in functional MRI studies. This method leverages changes in arterial transit time to boost activation constrast.

2394. Dynamic Measurement of Cerebral Perfusion Using CASL: A Tool for Assessment of Pharmacologic Activity in the Brain Denise C. Welsh1, Alexandre Coimbra1, David Williams1, Cyrille Sur1, Jacquelynn Cook1, Richard Hargreaves1, Donald S. Williams1 1Merck & Co.,Inc, West Point, Pennsylvania, USA

Arterial spin labeling (ASL) is used to assess dynamic cerebral perfusion following administration of compounds that modulate NMDA receptor function. Cerebral perfusion is increased following administration of the glycine site co-agonist D-serine, and decreased following GlyT1 inhibitor administration. Blockade of the NMDA glycine site with the antagonist L-701324 attenuated both the D-serine and GlyT1 inhibitor response, lending support to the idea that the changes in perfusion are related to NMDA activity. In conclusion, changes in cerebral perfusion, measured in vivo with non-invasive ASL, can provide a physiologic biomarker for assessment of the pharmacodynamic effects of novel psychoactive compounds.

2395. Neuroelectric Detection in FMRI Data of Frequent Interictal Activity in Patients with Epilepsy Roman Rodionov1, 2, Michael Siniatchkin3, Rachel Thornton1, 2, David W. Carmichael1, 2, Maxime Guye4, Adam Liston5, Louis Lemieux1, 2 1Institute of Neurology, University Colledge London, London, UK; 2MRI Unit, The National Society for Epilepsy, Chalfont St Peter, Buckinghamshire, UK; 3Christian-Albrechts-University, University Hospital of Pediatric Neurology, Kiel, Germany; 4INSERM, U 751, Laboratoire de Neurophysiologie et Neuropsychologie, France; 5London, UK

Previous experimental studies have suggested that direct detection of neuronal electrical (neuroelectric) activity using MRI might be possible. Here we perform neuroelectric analysis of resting-state EEG-correlated fMRI data in four patients with symptomatic epilepsy and extremely frequent focal interictal activity. All cases demonstrated regional signal changes putatively related to a fast neuroelectric response. We conclude that this phenomenon require further validation and that epileptic activity is a particularly suitable for this endeavor.

2396. Upper Bound Estimation of Neuronal Current-Induced Magnetic Field Changes in Humans Kevin Murphy1, Jerzy Bodurka1, Peter Anthony Bandettini1 1National Institute of Mental Health, Bethesda, USA

Direct MRI detection of neuronal activity is theoretically possible since the resulting ionic currents produce transient magnetic field changes that affect the measured signal. In this study, we employed EEG time series statistics to aid in the detection of these small effects and determine the lower limits of detectability in phantoms and humans. The sensitivity of this technique was investigated using a current phantom, simulations and human activation data. From the data, we have obtained an upper bound estimate of the size of the neuronal current effect using fMRI in humans on the order of 1nT.

Poster Sessions

396

Functional Brain Networks & Connectivity Hall D Wednesday 13:30-15:30

2397. Schematic Correlation Mapping of the Response Similarity Among the Brain Areas Using Dynamic FMRI Toshiharu Nakai1, Epifanio Bagarinao2, Yoshio Tanaka2, Chikako Nakai3, Masafumi Hiraoka1, Kayako Matsuo1 1National Center for Geriatrics & Gerontology, Ohbu, Japan; 2National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan; 3Toyohashi Sozo University, Toyohashi, Japan

Dynamic monitoring of t-statistics is potentially useful to monitor and characterize the ongoing the brain activities during switching of several task conditions. The correlation coefficients (CCs) of the t-statistics response function among the motor areas were obtained and schematically labeled on a wire-frame map (SCM). The dominance of the left higher motor areas during sequential movements of the left fingers could be systematically visualized. SCM is a data driven analysis without pre-defined restriction. This method will be useful to conceptually organize the dynamics of functional network including several brain areas.

2398. Dynamics for Functional Connectivity in 24-Hour Default-Mode Networks Hae-Jeong Park1, 2, Bumhee Park1, 2, Joong-il Kim1, 2 1Yonsei University College of Medicine, Seoul, Republic of Korea; 2Yonsei University College of Medicin, Seoul, Republic of Korea

The study evaluated the intra-individual variations of connectivity measures of default-mode network using fMRI according to brain states by measuring data during 24 hours, every 3 hours. The results showed that no significant difference between connectivity of different acquisitions times, which implies the long-term representation of the default-mode network. The fMRI of the default-mode network might be used to evaluate connectivity changes between groups.

2399. Deriving Unbiased Seed-Based Functional Connectivity Maps with an Iteration Strategy Wen-Jun Pan1, Hao Lei1 1Wuhan Institute of Physics and Mathematics, Chinese Academy of Science, Wuhan, People's Republic of China

Seed-based cross-correlation analysis (sCCA) has been widely used in functional connectivity MRI (fcMRI) studies. However, it is known that, with this method, the detected network may be biased by empirical and often subjective selection of the initial seed. To address this problem, here we propose a novel approach, seed-iteration cross-correlation analysis (siCCA), to examine the brain default network at rest. The method was shown to give results that are not dependent on the choice of the initial seed.

2400. High Spatio-Temporal Resolution Imaging of Resting State Fluctuations at 7T Natalia Petridou1, Andreas Schäfer1, Penny Gowland1, Richard Bowtell1 1University of Nottingham, Nottingham, UK

Studies have shown that physiological fluctuations at rest consist of BOLD and non-BOLD related noise. Here we investigate the spatiotemporal nature of these fluctuations at 7T, using a high spatial resolution where physiological and thermal noise are similar in magnitude, multiple TEs, and a short TR as to sample physiological fluctuations adequately. Both magnitude and phase were examined. At so high resolution, magnitude time series fluctuations consisted solely of BOLD related noise at frequencies <0.13Hz. Phase time series fluctuations increased with TE and were dominated by respiration, however, BOLD-like noise at frequencies <0.13Hz was observed.

2401. The Effect of Respiration Variations on Independent Component Analysis of Resting State Functional Connectivity Rasmus Matthias Birn1, Kevin Murphy1, Peter Anthony Bandettini1 1National Institute of Mental Health, Bethesda, Maryland, USA

MRI signal changes induced by variations in breathing depth and rate occur at low frequencies (<0.1Hz) and overlap with the default mode network, causing problems for functional connectivity analysis. In this study we investigate the impact of respiration changes on independent component analysis (ICA). We find that ICA can separate respiration-related from default mode network regions, but an independent measure of respiration is important to distinguish artifactual from neuronally relevant components. Furthermore, time series associated with the default mode network component are still significantly correlated with variations in respiration volume per time.

2402. The Effect of Motion on FMRI BOLD Resting State Low-Frequency Fluctuation Jaroslav Hlinka1, Charilaos Alexakis1, Paul S. Morgan1, Dorothee P. Auer1 1University of Nottingham, Nottingham, UK

Studies in spontaneous brain activity consistently reveal coherent low-frequency (0.01-0.1 Hz) fluctuations in areas spatially organized into functionally relevant networks (Resting State Networks). The power of these fluctuations has been proposed to reflect altered brain state, while the underlying mechanism is not understood. In our study, we have observed significant increase of low frequency fluctuation power in midazolam sedation in several ROIs including the visual cortex and callosal white matter. An in-depth analysis shows that the apparent increase of LFF power is attributable to the observed increase of motion accompanying sedation.

Poster Sessions

397

2403. Reliability of the Resting State Fluctuation Amplitude as a Hemodynamic Scaling Parameter Nirvish S. Shah1, Sridhar S. Kannurpatti1, Bharat B. Biswal1 1UMDNJ, Newark, New Jersey, USA

BOLD fMRI responses to a neural task can vary across brain regions, sessions and subjects depending on the underlying cerebro-vasculature and basal conditions. Though hypercapnia, induced through breath holding and CO2 inhalation, has been used for vascular reactivity studies, it is disadvantaged by various concerns such as patient compliance, evoked neural activity and requirement of additional equipment for hemodynamic scaling. Recently, we have observed high correlation between the resting state fluctuation amplitude (RSFA), breath hold response amplitude and CO2 response amplitude and demonstrated the use of RSFA for hemodynamic scaling. In this study, we have used the bootstrap resampling method to validate the use of RSFA as an alternative to hypercapnia-based scaling. Reliability of the correlation between RSFA, breath hold response amplitude and CO2 response amplitude was evaluated by bootstrapping the BOLD-fMRI time series. Stability of the correlation between RSFA, breath hold response amplitude and CO2 response amplitude was evaluated by bootstrapping varying lengths of the BOLD-fMRI time series.

2404. Functional Connectivity of the Motor Cortex: Test-Retest Reliability Neha Ravindra Shah1, 2, Steven R. Roys1, Jiachen Zhuo1, Joel M. Morris2, Rao P. Gullapalli1 1University of Maryland, School of Medicine, Baltimore, Maryland, USA; 2University of Maryland, Baltimore County, Baltimore, Maryland, USA

This study examines the spatial consistency of functional connectivity within the primary motor cortex of the resting brain within and across sessions. Seven subjects underwent two functional and three rest scans per session, during three separate sessions. Functional connectivity was determined using seven different sets of seed voxels from the motor cortex as identified from the motor activation scan. The functional connectivity maps obtained before and after filtering of physiological noise were found to be spatially consistent, within and across sessions. Although not significant, physiological filtering removes some of the variability in the results.

2405. Investigating Reproducibility of Working Memory Effective Connectivity Nia Goulden1, Shane McKie1, John Francis William Deakin1, Rebecca Elliott1 1University of Manchester, Manchester, UK

Studies carrying out effective connectivity analyses have a wide range of volunteer numbers. A typical number of volunteers for fMRI and effective connectivity analyses is 11 per group. Working memory tasks are likely to have variable results due to different volunteer abilities and strategies for carrying out the task, so 11 may not be a representative number. The aim of this work is to find out whether 11 volunteers is adequate for a study by comparing the results for independent groups of 11 volunteers.

2406. Gender Difference of Resting Rhythms Detected by BOLD-Based FMRI Tzu-Chen Yeh1, Wen-Jui Kuo2, Chou-Ming Cheng1, Jen-Chuen Hsieh1, Low-Tone Ho1 1Taipei Veterans General Hospital, Taipei, Taiwan; 2National Yang-Ming University, Taipei, Taiwan

The characteristic brain default network (tripod component) has been detected during resting by BOLD-based 3T fMRI studies. By identifying the default network using informax independent component analysis and automatic sorting using spatial template, resting BOLD-based fMRI studies of 40 normal subjects (gender- and age-matched) demonstrated the gender difference of resting default networks by group random-effect analyses. Men had relatively more extensive default network than women in bilateral posterior cingulate cortices (Brodmann Area 31).

2407. Functional Network Connectivity in Semantic Object Recall Task Using Independent Component Analysis Kanchana Jagannathan1, Michal Assaf1, 2, Vince D. Calhoun, 13, Godfrey D. Pearlson1, 2 1Institute of Living, Hartford, USA; 2Yale University, New Haven, USA; 3The MIND Institute , Albuquerque, USA

Using features to recall an object is a specific operation in semantic memory processing. The regions involved in the object-recall task were not significantly associated with the performance. We therefore hypothesized that temporal based dependency among independent component analyses ( ICA ) time courses would explain differences in neuronal network connections between good and poor performing healthy individuals. Consistent with our hypothesis, good performers showed higher correlation between language network, right hemisphere network and thalamus.

2408. Correction of the Low-Frequency Physiological Noise in the Resting State BOLD FMRI - Effect on the ICA Default-Mode Analysis at 1.5T Tuomo Henrik Starck1, Jukka Remes1, 2, Juha Nikkinen1, Osmo Tervonen1, Vesa Kiviniemi1 1Oulu University Hospital, Oulu, Finland; 2Oulu University, Oulu, Finland

Lagged estimates of the low-frequency respiratory and cardiac noise fluctuations and RETROICOR type of physiological correction have been shown to explain notable signal variance in the regression analysis of the resting state networks. Default-mode network spatially overlaps with regions significantly affected by physiological low-frequency fluctuations and they occur at similar frequencies, but it is not known how well ICA can separate noise processes from the default-mode network or other resting-state networks. This study showed that in spatial default-mode analysis, ICA accuracy does not improve significantly after physiological noise correction. In time and frequency domain studies correction may be beneficial

2409. A Conjunction Analysis-Based Approach to Compare the Lateralizing Power of FMRI Responses in Different Language Tasks Stephane, R Simon1, Mohamed, L Seghier, 2, François Lazeyras, Jean-Marie Annoni3, Asaid Khateb3 1Bio-Medical Imaging Center, Geneva University Hospitals, Geneva, Switzerland; 2Wellcome Trust Centre for Neuroimaging, Institute of Neurology, UCL, London, UK; 3Neuropsychology Unit, Geneva University Hospitals, Geneva, Switzerland

An original functional ROI-based approach was used to compute hemispheric laterality index obtained from four different linguistic tasks, in a group of healthy volunteers. Different ROIs were derived from the SPM conjunction group analysis based on all the tasks. The present data demonstrate the differential potential of the tasks to elicit clear regional hemispheric dominance. We conclude that the combination of several linguistic tasks, as well as the use of such a ROI-based approach is of great interest for pre-surgical mapping of language related areas.

Poster Sessions

398

2410. Motor Sequence Learning: A Functional Integration Study in FMRI David Coynel1, 2, Vincent Perlbarg1, 2, Guillaume Marrelec1, 2, Mélanie Pélégrini-Issac1, 2, Stéphane Lehéricy2, 3, Habib Benali1, 2 1Inserm and Université Pierre et Marie Curie, Faculté de médecine Pitié-Salpêtrière, Paris, France; 2IFR49 - Institut d'Imagerie Neurofonctionnelle, Gif-Sur-Yvette, France; 3Université Pierre et Marie Curie, Paris, France

We tested a model of motor sequence learning, according to which the representation of a motor sequence within brain areas shifts from a motor associative to a sensorimotor loop during the learning process. We used fMRI data to investigate the evolution of the motor network during learning. The network involved in the learning task was identified using spatial independent component analysis and hierarchical clustering. Then, the functional interactions within this network were quantified using a hierarchical integration measure. We demonstrated that learning induces changes in both the spatial structure of the motor network and its functional connectivity pattern.

2411. Long-Term Motor Training Induced Changes in Resting State Brain Liangsuo Ma1, Binquan Wang, Jinhu Xiong2 1University of Iowa, Iowa City, USA; 2University of Iowa,, Iowa City, USA

Functional activation often only reflects differentiated involvement and temporal relationship of brain regions compared between the task performance and the control states on a transient level. However, lasting changes in metabolic and hemodynamic physiology and synaptic plasticity induced by motor skill learning common to both states have not been elucidated. To address this issue, we explored long-term motor training induced neuronal and physiological changes in normal human subjects during task performance and resting state using MRI and PET. We have observed long-term motor training induced changes in both rCBF, which may reflect more fundamental changes in the brain.

2412. Modulation of Coherent BOLD Fluctuation in Human Visual Cortex with Continuous Brain Stimulation Xiao Liu1, 2, Xiao-Hong Zhu1, Wei Chen1 1University of Minnesota, Minneapolis, Minnesota, USA

The present study is to investigate the modulation of coherent BOLD fluctuations within human visual system under two conditions with continuous stimuli. We found that (i) under continuously-stimulated conditions, the activated brain region formed its own coherent network while the other inactivated regions of visual system still remained their temporal correlation as in resting-state; (ii) the coherent network at resting-state covered the widest areas and included some regions not activated by full-field visual stimulus; and (iii) no significant differences in terms of coherence strength were found among those two stimulation conditions and resting-state.

2413. Studying Coherent BOLD Fluctuation and Functional Connectivity of Cortico-Thalamic Visual Network in Anesthetized Cat Brain and Their Dependence on Anesthesia Depth Xiao Liu1, 2, Xiao-Hong Zhu1, Yi Zhang1, Wei Chen1 1University of Minnesota, Minneapolis, Minnesota, USA

The present study is to examine the coherent BOLD fluctuation and functional connectivity at resting-state in the anesthetized cat brain with the focus on the visual system. We found that the spontaneous BOLD signals detected in the LGN, PMLS, the areas 18 and 19 were temporally correlated with that in the area 17 (V1). We also observed that such coherence was much stronger at the light anesthesia condition than mild anesthesia condition. These findings not only prove the existence of coherent BOLD fluctuation in the cortico-thalamic visual pathway in the cat brain, but also provided clear evidence for the neural origin of coherent BOLD fluctuation.

2414. Regional Spontaneous Brain Activity in Male ADHD Revealed by Amplitude of Low Frequency Fluctuation Hong Yang1, 2, Qian-Qian Li, Min-Ming Zhang2, Xiang-Yu Long3, Lan-Ting Guo, Chao-Zhe Zhu3, Xiang-Ping Zhou1, Yu-Feng Zang3, Qi-Yong Gong1 1Department of Radiology, West China Hospital of Sichuan University, Chengdu, People's Republic of China; 2First Affiliated Hospital of College of Medical Science, Zhejiang University, Hangzhou, People's Republic of China; 3Beijing Normal University, Beijing, People's Republic of China

Using ALFF, to investigate the spontaneous activity in boys with ADHD. Seventeen boys with ADHD were compared with 17 controls. Data were acquired using 3T MRI system and data processing was performed using AFNI software. Significant decreased ALFF was found in the right inferior frontal gyrus, left supplementary motor areas and left anterior cingulate gyrus meanwhile significant increased ALFF was found in the bilateral superior frontal gyrus, left precentral gyrus and right ACG in ADHD patients compared with controls. The decreased spontaneous prefrontal activity is in line with the decreased response control function in prefrontal lobe of boys with ADHD.

2415. Modulation of Functional Connectivity in the Resting Brain by Typical and Atypical Antipsychotic Drugs Yazhuo Kong1, Shane McKie1, Anna Murphy1, Tirthankar Mukherjee1, Serdar Dursun1, Bill Deakin1, Steve Williams1 1University of Manchester, Manchester, UK

We investigated the default-mode network in normal volunteers using resting-state BOLD fMRI. 3 groups of subjects all had baseline scans, before receiving either placebo or the anti-psychotics risperidone (D2 antagonist/5HT2A antagonist) or aripiprazole (partial agonist). 3½ hours later they were rescanned. Group ICA was used for the identification of the default mode network nodes. Connectivity maps from anterior and posterior seed regions were generated for all conditions. Pre-drug and placebo maps were consistent with other descriptions of the default-mode network, but there was a significant decrease of the anterior to posterior connection for both drugs compared to pre-drug and placebo.

Poster Sessions

399

2416. Increased Resting State Dorsal Lateral Prefrontal and Medial Temporal FMRI Activation in Early Alzheimer’s Disease Xiaowei Song1, Kenneth Rockwood2, Ryan D'Arcy1, Alma Major3, John Fisk, Sultan Darvesh, Elissa Asp2, James Rioux1, Chris Bowen1, Steven Beyea1 1National Research Council Canada, Halifax, Canada; 2QEII Health Sciences Centre, Halifax, Canada; 3Dalhousie University, Halifax, Canada

This study investigates the characteristic fMRI fluctuation that exists at rest and how this differs between early AD patients and cognitively healthy adults, particularly in the dorsal lateral prefrontal cortex and the medial temporal lobe. The study suggests that there exist common patterns of neural activity fluctuation during rest. Patients with mild AD have increased resting state neural activity in both regions, suggesting the neural compensation effect in the early stages of AD progression. This study suggests that care needs to be taken with inferring cognitive task fMRI results when referenced to the resting state.

2417. Spontaneous BOLD Signal Changes Mimic Task-Related Activation in Anesthetized Rats Matthew Magnuson1, Shella Keilholz1 1Emory University/Georgia Institute of Technology, Atlanta, Georgia, USA

Electrical forepaw stimulation is a commonly used paradigm in rodent functional MRI. In recent experiments signal changes similar in magnitude and duration to those associated with stimulation were observed in scans where no stimulation was administered. This phenomenon was investigated further by comparing two groups of rats on two separate imaging systems under two diffent anesthsias; alpha-chloralose and medetomidine.

2418. Spatial Specificity of Functional Connectivity Maps for Different Frequency Bands in Rats Waqas Majeed1, Matthew Magnuson1, Shella Keilholz1 1Georgia Institute of Technology / Emory University, Atlanta, Georgia, USA

This abstract presents some initial resluts which suggest that frequncy band selection for filtering may impact spatial specificity and seed-location dependence of the connectivity maps.

2419. Effect of Different Frequency Bands on Functional Connectivity in the Motor Cortex Network Yin Xu1, Shi-Jiang Li1 1Medical College of Wisconsin, Milwaukee, Wisconsin, USA

Spontaneous low-frequency fluctuations (SLF) detected by functional MRI (fMRI) techniques have been utilized to investigate functional connectivity in human brain networks. The effective frequency band of the SLF signal is usually defined as 0~0.1Hz. However, few studies have investigated SLF signal at different narrower frequency bands. In the present study, we investigate the functional connectivity of SLF in the primary motor model and determine the effect of different frequency bands of the SLF signal on functional connectivity maps.

2420. Frequency Specificity of Functional Connectivity in Brain Networks Changwei Wesley Wu1, 2, Hong Gu1, Hanbing Lu1, Jyh-Horng Chen2, Elliot Stein1, Yihong Yang1 1National Institute on Drug Abuse, Baltimore, Maryland, USA; 2National Taiwan University, Taipei, Taiwan

The synchronous low-frequency fluctuations in the resting-state fMRI signal have been analyzed in the frequency domain and been evaluated through four brain networks (sensorimotor, visual, default mode, and limbic systems). The results show that strongest connections in these networks falls upon 0.01-0.06 Hz and discrepancies in the spectrograms subsist between brain networks. Our data also showed that long-distance connections seem to be more frequency specific, whereas short-distance connections are distributed in a wider frequency range. Such frequency-specific features in the resting state fMRI signal imply that brain networks have different spectral characteristics at rest.

fMRI: Multimodal Integration Hall D Thursday 13:30-15:30

2421. Distances Between EEG Spikes, BOLD Activation and Lesions for Different EEG Techniques Mario Forjaz Secca1, 2, Joana Cabral1, Henrique Fernandes1, Alberto Leal3 1Universidade Nova de Lisboa, Monte de Caparica, Portugal; 2Ressonancia Magnetica - Caselas, Lisboa, Portugal; 3Hospital Julio de Matos, Lisboa, Portugal

One of the common treatments in drug resistant Epilepsy is the surgical removal of the “offending” part of the brain and its success depends on the accurate localization of the focal region in the brain generating the seizures. The goal of EEG and MR Imaging is to help localization in presurgical evaluation, however the two techniques differ slightly and are not coincident with the lesion. So we quantified the distance between the EEG dipoles, the BOLD clusters and the lesions for different inverse problem approaches in order to develop analysis methods that diminish that discrepancy.

2422. The Relationship Between the FMRI BOLD Response and Beta Band Neuromagnetic Effects Claire Stevenson1, Matthew Brookes1, Peter Morris1 1The University of Nottingham, Nottingham, UK

There is a good correlation between fMRI BOLD data and induced oscillatory effects in MEG. Here, the induced oscillatory response in the beta-band is measured by MEG and the haemodynamic response is measured by fMRI for both finger movement of varying durations and visual stimuli of varying contrast. The linearity of the responses is assessed in order to determine the extent to which the BOLD response is governed by beta activity. The excellent co-localisation of BOLD and beta activity strongly suggests that the two processes are linked.

Poster Sessions

400

2423. Assessment of BOLD Signal Adaptation Using Single Event FMRI at 7 T and Its Correlation with MEG Peter J. Wright1, M Brookes1, J Dixon1, P Morris1, P Gowland1, S Francis1 1University of Nottingham, Nottingham, UK

Recent studies have shown the fMRI BOLD response becomes smaller over time, suggesting a degree of adaptation of the response. However the indirect nature of the BOLD response means that the cause of this adaptation is unclear. In the present work we compare the degree of adaptation observed using both MEG and fMRI at 7 T. Results show that 7 T fMRI can be used to measure and fit the haemodynamic response on a trial by trial basis. We found adaptation in the fMRI response but not the MEG evoked response to median nerve stimulation in two subjects.

2424. Is the Habituation of the Visual Evoked EEG Response Reflected in the Simultaneously Acquired BOLD and ASL FMRI Signals? Stephen Daniel Mayhew1, 2, Bradley John MacIntosh1, Sharon G. Dirckx1, Kyle T.S Pattinson1, Richard Geoffrey Wise2 1University of Oxford, Oxford, UK; 2University of Cardiff, Cardiff, UK

We investigated the neurovascular coupling in the human brain between the visual-evoked responses measured during simultaneous recording of EEG-BOLD and EEG-ASL. We correlated the temporal features of BOLD and CBF signals with EEG measurements of the underlying neural activity. A significant decrease in the amplitude of the visual-evoked EEG response was measured across a 30-s block of stimulation. No corresponding habituation was measured with BOLD fMRI, but a significant subtle habituation of the CBF response was measured using a region-of-interest based analysis. This suggests the neuronal EEG response may be better temporally correlated with CBF than with BOLD haemodynamic fMRI signals.

2425. Validation of Calibrated MRI Using Continuous-Wave and Time-Domain Near-Infrared Spectroscopic Imaging Claudine Gauthier1, 2, Louis Gagnon, 23, Juliette Selb4, David Boas4, Frédéric Lesage, 23, Richard D. Hoge1, 2 1Université de Montréal, Montreal, Canada; 2Institut de gériatrie de Montréal, Montreal, Canada; 3École Polytechnique de Montréal, Montreal, Canada; 4Massachusetts General Hospital, Charlestown, Massachusetts, USA

MRI-based estimates of task-induced changes in oxygen consumption were validated using near infrared spectroscopic imaging in both continuous-wave and time-domain modes. This combination of optical measures allowed determination of the fractional change in tissue deoxyhemoglobin concentration, which was compared with values implied by the MRI model during hypercapnia and a motor task. Fractional dHb changes during hypercapnia were in close agreement for the two methods. Changes measured by optical imaging during the task were lower than those suggested by MRI, to a degree consistent with the partial volume effect in the optical data.

2426. Simultaneous EEG-FMRI Acquisition: Effect of Choice of MRI Pulse Sequence on Gradient Artifacts and EEG Data Quality Hari M. Bharadwaj1, Scott Peltier1, Douglas C. Noll1, Jinsoo Chun1, Patricia J. Deldin1 1University of Michigan, Ann Arbor, USA

Multimodal functional neuroimaging with EEG and fMRI offers great promise for the future. With the advent of a wide variety of pulse sequences for fast and high resolution fMRI, it is necessary to understand the effect of the choice of pulse sequence on EEG data quality in multimodal experiments. A study was performed using two commonly used pulse sequences:EPI and Spiral. Both task activation and resting state conditions were studied. The gradient artifacts were removed independently using 2 different artifact removal algorithms. It was found that the EEG data acquired concurrently with EPI was more akin to the EEG data acquired during no MR acquisition. This is attributed to the fact that the EPI gradient waveforms are spectrally disjoint with the EEG bands on interest (0-70 Hz) and the Spiral gradients have significant overlap.

2427. Minimalist EEG-Recording for Improving FMRI: Simple Encoding of Noise Variables in MRI Data Lars G. Hanson1, Arnold Skimminge1, Christian G. Hanson1 1Copenhagen University Hospital, Hvidovre, Denmark

Most fMRI studies can benefit from simultaneous recording of EEG and other electrophysiological signals, even when EEG is not of interest in itself. It is demonstrated that simple hardware and few, easily positioned electrodes can provide measures of eye-blinks, alpha-activity and pulse that increases fMRI sensitivity and reliability. The analysis is facilitated by EEG and MRI being measured and stored together by the scanner.

2428. A New Hardware-Software Coil Positioning System for Interleaved TMS/fMRI: A Motor Cortex Stimulation Study Marius Moisa1, Kamil Uludag1, Kamil Ugurbil1, Axel Thielscher1 1Max Planck Institute for Biological Cybernetics, Tübingen, Germany

Interleaved TMS/fMRI is a promising technique to study connectivity between brain areas. An important practical challenge is the positioning of the coil inside the MRI scanner. We describe a novel method that combines software and hardware for accurate TMS coil placement and report pilot results on its usage studying the motor system. In a phantom study, the accuracy of the method was demonstrated to be within the range previously reported for normal neuronavigation systems. The results of the motor cortex study are in concordance with prior findings, demonstrating the viability of our positioning method and our overall interleaved TMS/fMRI setup.

2429. Improved Artifact Rejection for Simultaneous EEG/fMRI at 7T Using a High EEG Channel Density and a Vector Beamformer Matthew Jon Brookes1, Karen Julia Mullinger1, Gerda Bjork Geirsdottir1, Claire Michelle Stevenson1, Peter Gordon Morris1, Richard William Bowtell1 1University of Nottingham, Nottingham, UK

Previously it has been shown that the application of a vector beamformer to EEG data recorded simultaneously with fMRI allows for source localization of electrical responses, extraction of the timecourse of neuronal activity and rejection of residual artifacts induced in the EEG data by the MR scanner. In this work we show that the signal to noise ratio of beamformer-reconstructed estimates of electrical activity is improved by the use of increased numbers of EEG channels. Furthermore, we show that the beamformer approach allows for the measurement of low amplitude, high frequency gamma band electrical effects at ultra high field (7T).

Poster Sessions

401

2430. Electrical and Haemodynamic Effects Measured Using MEG and Combined EEG/fMRI Matthew Jon Brookes1, Karen Julia Mullinger1, Claire Michelle Stevenson1, Gerda Bjork Geirsdottir1, Richard William Bowtell1, Peter Gordon Morris1 1University of Nottingham, Nottingham, UK

Recent MEG studies have shown that evoked (1-40Hz) and gamma band (50-200Hz) neuronal responses can be measured in the 100ms time window immediately following electrical stimulation of the median nerve. Here we measure these characteristic responses using both MEG and EEG recorded simultaneously with 7T fMRI. We show that a combination of averaged artifact subtraction and an EEG beamformer allows for adequate SNR to record low amplitude gamma band effects in EEG/fMRI. Furthermore, we show that the EEG and MEG signals are temporally comparable to each other, and spatially coincident with the haemodynamic response.

2431. An Approach for Fusion Between EEG and FMRI Data Lei Wu1, 2, Vince Daniel Calhoun1, 2 1The Mind Research Network, Albuquerque, New Mexico, USA; 2University of New Mexico, Albuquerque, New Mexico, USA

An improved ICA to fuse multi-channel ERP and fMRI with high spatialtemporal resolutions in AOD tasks was presented. We acquired and preprocessed the data first, then used PCA data reduction, pseudo reconstruction, jICA capturing relationships between different modalities and hybrid data simulation. For all sub-methods, the components can be separated well. Different peaks of ERP match different regions of activities of fMRI. The ERP components from multi-channels correspond better to sources than those from single channels. Dipolar close to cz channel works better than other locations. Therefore, we can reveal the EEG-fMRI signals’ relationship and enhance the visualization of neural responses.

2432. Near-IR Optical Calibration of the BOLD Signal Theodore J. Huppert1, Solomon G. Diamond2, David A. Boas3 1University of Pttsburgh, Pittsburgh, Pennsylvania, USA; 2Dartmouth College, USA; 3Massachusetts General Hospital, USA

In this work, we use concurrently measured near-IR optical measurements to calibrate the BOLD signal. We develop a data fusion model to incorporate both optical and BOLD measurements into a unified model of the underlying hemodynamic response. Through simulations and experimental results, we demonstrate the improved quantitative accuracy of our model.

2433. Current Density Weighted Indices for Correspondence Between FMRI with Electrocortical Stimulation Maps Desmond Teck Beng Yeo1, 2, Charles R. Meyer2, Jack M. Parent2, Daniela N. Minecan2, Oren Sagher2, Karen J. Kluin2, Boklye Kim2 1University of Michigan, Ann Arbor, Michigan, USA; 2University of Michigan Medical School, Ann Arbor, Michigan, USA

The gold standard for presurgical brain mapping is subdural electrocortical stimulation (ECS), which is an invasive procedure. Functional MRI (fMRI), a non-invasive technique, may be a plausible alternative. However, it must be shown that fMRI-ECS activation maps are spatially consistent. There are indications that the level of elicited neuronal activation is influenced by electrical stimulus levels, and thus, a correspondence index that incorporates current density information may be physically more meaningful. This work formulates a 3D current density weighted method to measure ECS-fMRI correspondence for our clinical ECS-fMRI mapping procedure. Euclidean distance information between activated voxels and ON/ OFF electrode pairs is embedded in current density maps obtained by solving the Laplace equation for a quasistatic volume conductor. The proposed current density weighted indices were computed for three patient datasets.

fMRI: Animal Models Hall D Monday 14:00-16:00

2434. BOLD and Blood Volume-Weighted FMRI of Rat Lumbar Spinal Cord During Non-Noxious and Noxious Hindpaw Stimulation Fuqiang Zhao1, Mangay Williams1, Xiangjun Meng1, Denise Welsh1, Alexandre Coimbra1, Eric Crown1, Catherine Abbadie1, Jacquelynn Cook1, Mark Urban1, Richard Hargreaves1, Donald Williams1 1Merck Research Laboratories, West Point, Pennsylvania, USA

This study investigates the reproducibility, robustness, and spatial accuracy of fMRI of lumbar spinal cord activation due to transcutaneous noxious and non-noxious electrical stimulation of the hindpaw in á-chloralose anesthetized rats. BOLD and Blood Volume-weighted fMRI data were acquired without and with intravenous injection of USPIO, respectively. Neuronal activation in the spinal cord induced by noxious stimulation can be robustly detected by both fMRI techniques with excellent reproducibility. Spatially, the fMRI signal extended ~5 mm in the longitudinal direction, covering L3-L5 segments. In the cross-sectional direction, the highest signal change of BV-weighted fMRI was in the middle of the ipsilateral dorsal horn, which roughly corresponds to laminae V and VI, while the highest signal change of BOLD fMRI was in the ipsilateral dorsal surface. This study demonstrates that spinal cord fMRI can be performed in anesthetized rats reliably and reproducibly offering it as a potential tool for analgesic drug discovery.

2435. BOLD and Blood Volume-Weighted FMRI of Rat Cervical Spinal Cord with GE and SE EPI Fuqiang Zhao1, Mangay Williams1, Xiangjun Meng1, Denise Welsh1, Eric Crown1, Alexandre Coimbra1, Catherine Abbadie1, Jacquelynn Cook1, Mark Urban1, Richard Hargreaves1, Donald Williams1 1Merck Research Laboratories, West Point, Pennsylvania, USA

fMRI results of cervical spinal cord with regard to the spatial extension, in both longitudinal and cross-sectional direction, of neuronal activation are inconsistent and inconclusive. Previous cervical spinal cord fMRI experiments were mainly performed using a fast spin echo (RARE) sequence because of it is less sensitive to magnetic field inhomogeneities, but compromising fMRI sensitivity. In this study, we investigate the feasibility of pain fMRI in the cervical spinal cord by BOLD and Blood Volume-weighted fMRI using gradient echo (GE) and spin-echo (SE) EPI in á-chloralose anesthetized rats at 7T In BOLD and BV-weighted fMRI, the largest signal changes occur at the spinal cord segments of C4 to C8 in rostral-caudal direction, and in the ipsilateral dorsal horn in cross-sectional direction. An advantage compared to a RARE sequence is EPI's better temporal resolution allowing acquisition of more data to improve the statistical power of fMRI signal detection.

Poster Sessions

402

2436. BOLD FMRI Investigation of Trigeminal Nerve Stimulation at 9.4T Nathalie Just1, Hanne Frenkel, Rolf Gruetter2 1UNIL,EPFL, Lausanne, Switzerland; 2UNIL,EPFL, University of Geneva, Lausanne, Switzerland

The vibrissal system of the rat is an interesting system to explore structure, function, development and plasticity within the somatosensory cortex because of the functional and morphological correlation between the vibrissae and the barrels. In the present study, single shot EPI gradient echo fMRI of the rat brain at 9.4T was used to map barrel activation during electrical stimulation of the trigeminal nerve. The aim of this study is to establish a reproducible paradigm to measure the BOLD_fMRI response to trigeminal nerve stimulation and determine a relationship between neuronal activity and BOLD changes in the rat somatosensory cerebral cortex.

2437. CBV-Weighted FMRI Study of Neurovascular Coupling in the Caudate Putamen Following Graded Electrical Stimulation in the Forepaw of Rats Yen-Yu Shih1, 2, You-Yin Chen3, Chiao-Chi Chen2, Bai-Chuang Shyu2, Tiing-Yee Siow2, Zi-Jun Lin2, Jyh-Cheng Chen4, Fu-Shan Jaw1, Chen Chang2 1National Taiwan University, Taipei, Taiwan; 2Academia Sinica, Taipei, Taiwan; 3National Chiao-Tung University, Hsinchu, Taiwan; 4National Yang-Ming University, Taipei, Taiwan

This is the first imaging study that demonstrates the role of caudate putamen in pain-induced neurovascular processing. By evaluating CBV responses following graded electrical stimulation (5 ¡V 60V), salient bilateral vasoconstriction effect was observed specifically in the caudate putamen, while vasodilation only appeared in the contralateral somatosensory cortex.

2438. Mapping Plasticity in the Forepaw Digit Barrel Subfield of Rat Brain Using Functional MRI Jun-Cheng Weng1, 2, Kai-Hsiang Chuang1, Artem Goloshevsky1, Stephen Dodd1, Jyh-Horng Chen2, Alan P. Koretsky1 1National Institutes of Health, Bethesda, Maryland, USA; 2National Taiwan University, Taipei, Taiwan

This well-defined relationship between the cortical barrels and the forepaw digit makes this system a good model for the study of neuronal function and plasticity. Although the representation of digit columns has been previously investigated by optical imaging of intrinsic signal, mapping this topographically organized representation non-invasively remains challenging. Functional MRI (fMRI) has been shown to map columns in cat visual as well as in rodent whisker barrels. The goal of this study was to test the feasibility of and to optimize fMRI to map the forepaw digit representations in the SI of the rat. Further, this technique was applied for mapping brain plasticity after digit amputation.

2439. Assessment of Functional Cortical Plasticity with BOLD FMRI Mapping of Adjacent Somatosensory Representations in Rat Artem G. Goloshevsky1, Stephen J. Dodd1, Alan P. Koretsky1 1National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, USA

Assessment of the reorganizational capacity of adult brain is important for the investigations of the mechanisms of functional cortical plasticity. In this work, a three-dimensional BOLD fMRI mapping of somatosensory limb representations was used to study cortical reorganization in adult rat brain, 2-3 weeks following the peripheral nerve deafferentiation (5 weeks old rats underwent an excision of the sciatic and saphenous nerves in a hindpaw). A sufficient data averaging significantly improved the delineation of the fMRI maps, and the alteration of the map profiles demonstrated an expansion of the forepaw representation into the cortical area corresponding to the hindpaw. Thus, the technique allowed a detailed mapping of the induced plasticity of the cortical somatosensory representations when employed in rats.

2440. Somatotopic Plasticity of the BOLD Response Following Spinal Cord Injury in Rats: Use of Anatomical Landmarks on EPI Images for Accurate Topological Mapping Esther Gertrud Sydekum1, Christof Baltes1, Arko Ghosh2, Thomas Mueggler1, Martin Schwab2, Markus Rudin2, 3 1University and ETH , Zurich, Switzerland; 2University of Zurich, Switzerland; 3University and ETH, Zurich, Switzerland

Assessment of changes in functional topology of the cortex with fMRI depends on the quality of the reference coordinate system. We have used a highly reproducible artifact caused by the Bregma line on coronal EPI images recorded at 9.4T as geometrical reference to map fMRI data to Paxinos brain atlas. The accuracy of the method was evaluated by analyzing the sensory representation of fore and hind paw derived from BOLD-fMRI using electrical stimulation. As application we studied plastic events in cortical area S1 after spinal cord injury: both the temporal profile and the spatial extent of the response were altered.

2441. Cortical Plasticity of the Brain After Median Nerve Transection Using FMRI at 9.4T by Direct Nerve Stimulation Seth Reuben Jones1, Rupeng Li1, Chris Pawela1, Daniel L. Shefchik1, Hani Matloub1, Ji-Geng Yan1, Safwan Jaradeh1, James S. Hyde1 1Medical College of Wisconsin, Milwaukee, Wisconsin, USA

A clinical observation provided by our peripheral nerve surgeons is that after transection of a single nerve, in many cases the median nerve, the patient will get partial return of sensory function at the borders between adjacent nerve sensory distributions. We hypothesize this is a form of brain plasticity and the adjacent nerves will show an expansion of cortical signal with direct nerve stimulation. In a mulidisciplinary effort we created a rat model that we believe shows plasticity while providing a clinical correlate

2442. Longitudinal FMRI in Rats Following Spinal Cord Lesion and Spontaneous Functional Improvement Dirk Wiedermann1, Veronica Estrada2, Nicole Brazda2, Anreas Beyrau1, Pedro Ramos-Cabrer3, Hans-Werner Mueller2, Mathias Hoehn1 1Max Planck Institute for Neurological Research, Cologne, Germany; 2Heinrich Heine University, Düsseldorf, Germany; 3Hospital Clínico Universitario, Universidad de Santiago de Compostela, Santiago de Compostela, Spain

After spinal cord injury (SCI) axonal regeneration is impeded, but previous studies have also reported spontaneous regeneration of motor function. Here, we present an investigation on the recovery of the somatosensory system in female rats after SCI using longitudinal fMRI studies. The main challenge of longitudinal fMRI is a suitable anesthesia. Therefore we developed an anesthesia protocol for female rats suitable for robust and repetitive fMRI, with a measurement protocol to perform reliable, longitudinal fMRI in SCI and followed up of the spontaneous recovery after SCI with fMRI up to 11 weeks post injury.

Poster Sessions

403

2443. Invasion of Whisker Cortical Maps by Adjacent Forepaw Representations Visualized with BOLD FMRI Benito de Celis Alonso1, Andrew S. Lowe2, John P. Dear3, Kalok C. Lee4, Gerald T. Finnerty5 1King´s College London, London, UK; 2UCL London, UK; 3Imperial College, London, UK; 4King’s College London, UK; 5MRC Centre for Neurodegeneration Research, UK

The adult brain is not hard-wired, but changes with experience. We reported recently that reorganization in adult rodent somatosensory cortex induced by whisker trimming can be visualized with BOLD fMRI. Here, we use BOLD fMRI to ask whether plasticity is restricted to the sensory input that is altered, i.e. the whiskers, or whether other non-deprived sensory maps, e.g. forepaw, reorganize. Our findings indicate that non-traumatic sensory deprivation is sufficient to cause expansion of adjacent representations that are not directly modified by the deprivation protocol. This suggests that cortical representations compete with adjacent representations for cortical space in the normal brain.

2444. 11.74T FMRI of Cortical and Subcortical Visual Networks in the Rat Christopher Bailey1, 2, Basavaraju Sanganahalli1, Alyssa Siefert3, Peter Herman1, Albert Gjedde2, Fahmeed Hyder1 1MRRC, Yale University, New Haven, Connecticut, USA; 2CFIN, Aarhus University, Aarhus, Denmark; 3Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA

Though a predominantly nocturnal animal, the rat has a fully functional visual system. Here we developed methods to probe this sensory system with both high field fMRI and electrophysiological techniques. Our design of stimulus delivery differs from the stroboscopic-based or dark-light adapted systems which generate very robust intensity stimuli. We demonstrate that our stimulus delivery method elicits weak but reproducible brain responses to track hemodynamic and electrophysiological signal changes in cortical and subcortical structures of the rat visual pathway. We demonstrate stimulus frequency-dependent correlations between electrical and BOLD signal changes in the primary visual cortex.

2445. fMRI of Delay and Trace Eyeblink Conditioning in the Visual Cortex of the Rabbit Michael J. Miller1, 2, Craig Weiss3, Gheorghe Iordanescu2, 3, Xiaomu Song2, 3, John F. Disterhoft3, Alice M. Wyrwicz2, 3 1Northwestern University, Evanston, Illinois, USA; 2Evanston Northwestern Healthcare Research Institute, Evanston, Illinois, USA; 3Northwestern University Feinberg Medical School, Chicago, Illinois, USA

We used fMRI in parallel with delay and trace eyeblink conditioning to image learning-related functional activation within the primary visual cortex (V1). Our results indicate that these paradigms produce distinct patterns of functional change in V1 with learning. Trace conditioning produced an expansion of activated area, without any change in maximum BOLD magnitude, whereas the simpler delay paradigm showed an increase in maximum BOLD magnitude but no accompanying change in area. These differences suggest that the recruitment of additional neurons in V1 is necessary to support the more demanding memory of the trace paradigm.

2446. Post-Oral Nutritive Substances Elicit Brain Activation in Rats Tomokazu Tsurugizawa1, Takashi Kondoh1, Kunio Torii1 1Ajinomoto Co., Inc., Kawasaki, Japan

Recent studies have shown that post-oral nutritive taste substances are critical in determining preference and appetite for foods. We showed spatio-temporal activation in the higher center of the brain by sweet (glucose), umami (MSG) or salty (NaCl) substances. Subdiaphragmatic total vagotomy (TVX) eliminated the activation by MSG and NaCl. While, glucose was affected little by TVX. These results indicated that post-oral nutritive taste substances activate higher center of the brain via vagal or non-vagal (humoral or spinal) pathway.

2447. Functional Magnetic Imaging of Neural Activity in Rat CNS in Response to Chromatic Stimuli Christopher Paul Pawela1, Matt C. Mauck1, James Kuchenbecker2, Anthony G. Hudetz1, Jay Neitz1, James S. Hyde1 1Medical College of Wisconsin, Milwaukee, USA; 2Marquette University, Milwaukee, USA

For the first time the response to chromatic stimuli was studied in the visual system of the rodent. This study is an important first step toward developing a CNS model to evaluate the functional consequences of newly introduced therapeutic opsin molecules targeted to either M- or S- photoreceptors.

2448. BOLD FMRI of Sensory Forepaw Stimulation in Mice Using a Cryogenic RF Probe Operating at 400 MHz Simone Claudia Bosshard1, Christof Baltes1, Thomas Mueggler1, Markus Rudin1 1ETH and University of Zürich, Zürich, Switzerland

The feasibility of BOLD fMRI in mouse after somatosensory forepaw stimulation was investigated using the highly sensitive cryogenic RF transceiver probe. The experiment was performed under isoflurane anesthesia in artificially ventilated and constantly monitored mice. GLM (general linear model) analysis of sequential bilateral forepaw stimulation at 1.5mA and 3Hz showed statistically significant activation in the sensory cortex. BOLD signal changes peaked at 0.85±0.21% on the contralateral and at 0.82±0.23 on the ipsilateral side. This study demonstrates that the use of a cryogenic RF probe provides the high sensitivity required for detection of BOLD changes in small rodents such as mice.

fMRI Correction Strategies Hall D Tuesday 13:30-15:30

2449. Respiratory Noise Correction Using Phase Information Hu Cheng1, Yu Li2 1Indiana University, Bloomington, Indiana, USA; 2Invivo Corporation, Gainesville, Florida, USA

A new method, respiratory noise correction using phase information (RCP), was developed to reduce the respiratory signals in fMRI data. This method takes advantages of the respiration information in the phase signal of complex fMRI data and does not need extra data acquisition. It was demonstrated that the respiratory noise can be removed efficiently using this method. The new method is compared with RETROICOR and shows better performance when the respiration deviates from being quasi-periodic. This technique is useful for correcting respiratory noise from abnormal breathing.

Poster Sessions

404

2450. Novel Correlated Noise Suppression Method Substantially Improves Detection of FMRI Response to Weak Stimuli at 7 T Marta Bianciardi1, Masaki Fukunaga1, Jeff H. Duyn1, Peter van Gelderen1, Jacco A. de Zwart1 1National Institutes of Health, Bethesda, Maryland, USA

Higher magnetic field strength has certain benefits for fMRI, such as increased intrinsic contrast-to-noise ratio and specificity. However, contribution of physiologic and other spatially correlated noise typically increases with field strength, dominating temporal stability in voxels as small as 1 mm3 at 7 T. We demonstrate the benefits of a novel spatially correlated noise suppression method for the detection of the fMRI response to weak visual stimuli at 7 T. The correlated noise suppression method yielded an increase in detection power of 86 % for three PCA-derived correlated noise regressors and 64 % for a single correlated noise regressor.

2451. Sliding Window SENSE Calibration for Reducing Noise in FMRI Christine S. Law1, Chunlei Liu, Gary H. Glover 1Stanford University, Stanford, California , USA

We propose a self-calibrated parallel imaging fMRI method in which sensitivity profiles are calculated dynamically using a sliding window approach: averaging a small number of consecutive fully-sampled multishot images. This technique provides an SNR gain over conventional SENSE reconstruction. For conjugate gradient CG-SENSE reconstruction (1,2), profiles are updated at every time frame. No spatial smoothing is performed so as to retain thermal noise in sensitivity profiles. Sliding window width determines similarity between thermal noise in sensitivity profiles and thermal noise in the windowed raw data. Narrower window width yields more similarity and provides better noise cancellation in the reconstructed image time-series. This sliding window technique is especially applicable to acquisition of high spatial-resolution images (where thermal noise dominates over physiological noise). Activation from visual stimulation is revealed where conventional sensitivity calculations falter.

2452. Improved Physiological Noise Modelling for Brainstem Functional Imaging Jonathan Brooks1, Ann Harvey1, Kyle Pattinson1, Mark Jenkinson1, Richard Wise2 1Oxford University, Oxford, UK; 2School of Psychology, Cardiff, UK

Respiratory and cardiac effects contribute towards signal variability found in functional magnetic resonance imaging (FMRI) signals. A modified version of the retrospective image correction (RETROICOR) method for physiological noise correction was implemented on resting brainstem echo-planar imaging (EPI) data. The optimal model contained 3 cardiac (C) and 4 respiratory (R) harmonics, and 1 multiplicative (X) term. Interactions between cardiac and respiratory fluctuations were a significant source of physiological noise in brainstem EPI data. Using this model, increased significance of pain-related brainstem activation was detected when compared to a model which did not account for physiological noise.

2453. Spectral-Spatial Pulse Design for Signal Recovery in T2*-Weighted BOLD Functional MRI Chun-yu Yip1, Sangwoo Lee2, William Grissom1, Jeffrey A. Fessler1, Douglas C. Noll1 1University of Michigan, Ann Arbor, Michigan, USA; 2GE Healthcare, Waukesha, Wisconsin, USA

We propose a method of using specially designed spectral-spatial pulses for signal recovery in T2*-weighted BOLD fMRI. It is a novel approach to precompensate for through-plane dephasing between excitation and acquisition. It is effective in signal recovery even when the field offset is high and there are multiple signal loss regions. The pulses can be computed and stored offline, and retrieved for deployment during an fMRI experiment (no online computation needed).

2454. Minimization of Nyquist Ghosting for FMRI at Ultra-High Fields Based on a ‘negative Read-Out Gradient’ Strategy Wietske van der Zwaag1, 2, Hongxia Lei1, 2, Nathalie Just1, 2, José Marques1, 2, Rolf Gruetter1, 3 1Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland; 2University of Lausanne, Lausanne, Switzerland; 3Universities of Lausanne and Geneva, Switzerland

The increased frequency distribution at high B0 results in more substantial Nyquist ghosting. The traditional ghost correction approach based on acquiring reference k-space lines without phase-encode gradient was supplemented with schemes based on continually reversing read-out polarity in EPI in every other volume. Three strategies were evaluated in rat brain at 9.4 Tesla, all of which substantially reduced the ghosting up to 70%, resulting in up to 40% increase in activated areas and higher Z-scores. We conclude that at very high B0, substantial gains are possible by alternating the read-out gradient every other volume, allowing continuous artefact reduction.

2455. A Shimming Procedure for FMRI, Optimizing the Local BOLD Sensitivity Evelyne Balteau1, 2, Nikolaus Weiskopf2 1University of Liege, LIEGE, Belgium; 2University College London, LONDON, UK

Field inhomogeneities are well-known to lead to severe dropouts and geometric distortions in echo-planar images. The optimization of the field homogeneity or shimming, is therefore an important step in the imaging process. However in fMRI, the BOLD sensitivity is the measure of interest, and it is only indirectly related to the spatial variation of the magnetic field. In particular, it depends on the EPI signal and the local TE. A regularized algorithm is presented to optimize the BOLD sensitivity, as a fMRI-dedicated shimming procedure, and an alternative to the shimming algorithms based on field homogeneity only.

2456. Optimising TR for Fitting Single Trial HRFs Peter J. Wright1, M Brookes1, J Dixon1, S Francis1, P Gowland1 1University of Nottingham, Nottingham, UK

With the advent of ultra-high field MRI scanners single trial fMRI is fast becoming a reality, allowing the quantification of trial-by-trial variations to response to stimulation. This work aims to determine optimum TR to acquire single trial data through Monte Carlo simulations fitting a Gaussian variate with added noise along with experimental confirmation from 2 subjects scanned at 7 T. Results showed that for simulation the random error was relatively constant for TR up to the time-to-peak of the HRF with experimental results showing a similar trend with a tendency for errors to increase relative to simulations for long TR.

Poster Sessions

405

2457. Apodization and Smoothing Alter Voxel Time Series Correlations Andrew S. Nencka1, Daniel B. Rowe1 1Medical College of Wisconsin, Milwaukee, Wisconsin, USA

Apodization is a standard pre-reconstruction process used to reduce Gibbs ringing in Fourier reconstructed data and is prominently used in spiral reconstruction. Similar to Gaussian smoothing, apodization effectively includes convolving image space data with the Fourier transform of the k-space apodization window. This convolution spreads a voxel’s signal over its neighboring voxels. We illustrate in this abstract that such a convolution process induces non-negligible effects in voxel time series correlations. This suggests that voxel time series correlation considerations can be improved with proper adjustment for the effects of pre-processing operations.

2458. Cardio-Respiratory Effects on the Phase in EPI Chloe Hutton1, Eric Featherstone1, Nikolaus Weiskopf1 1UCL, London, UK

Several studies have shown that cardio-respiratory effects can be a confound in fMRI. However, the characteristics of these effects on phase in EPI are not well understood. In this work, the spatial characteristics of cardiac pulsatility and respiration are identified for phase and magnitude data constructed from a standard EPI sequence. Statistical maps indicate how phase and magnitude images are differentially affected by cardiac and respiratory effects. These results suggest that robust methods for physiological noise correction should be based on both phase and magnitude data.

2459. Large-N Coil Arrays Decrease the Scantime Required to Accurately Identify Cortical Visual Areas Oliver Hinds1, Michael Hamm, Karsten Jahns2, Franz Hebrank, Christina Triantafyllou1 1MIT, Cambridge, Massachusetts, USA; 2Siemens Medical Solutions, Erlangen, Germany

Large-n array coils provide increased SNR for fMRI. While computingthe benefit of increased SNR on detection of BOLD-related signalchanges is straightforward, the effective benefit for fMRI analysesthat do not share a simple relationship to SNR must be determinedempirically. Here, we compare the accuracy of the estimated locationof cortical area V1 derived from images acquired using a prototype32-channel phased-array head coil and with a standard 12-channel headcoil. We report that the 32-channel coil provides an approximatelyfour-fold decrease in the scantime required for V1 estimates ofcomparable quality.

2460. A Quadrant-Specific Monocular Visual Functional MRI Paradigm Designed to Minimize Attention and Loss-Of-Fixation Biases Thomas M. Jenkins1, Laura Mancini2, Ahmed T. Toosy1, Olga Ciccarelli1, Gordon T. Plant2, 3, David H. Miller1, Alan J. Thompson1 1Institute of Neurology, London, UK; 2National Hospital for Neurology and Neurosurgery, London, UK; 3Moorfields Eye Hospital, London, UK

Synopsis: We describe a novel quadrant-specific visual fMRI paradigm using red/green filter goggles to isolate each eye. The technique facilitates monocular stimulation of both eyes within the same scanning run, and minimizes the risk of fixation loss in subjects with monocular blindness.

2461. Inter-Subject Heterogeneity: -When a Fixed Effects Analyses Fixes the Problem Torben E. Lund1, 2, Kristoffer H. Madsen2, 3, Kirsten Korsholm2 1Aarhus University, Aarhus, Denmark; 2Hvidovre Hospital, Hvidovre, Denmark; 3Technical University of Denmark, Lyngby, Denmark

In patients with optic neuritis (ON), location and severity of scotomas in the acute phase can vary greatly and may be central, paracentral, quadrantic, or small defects in the periphery. Over time the the Patients with ON undergo cortical and subcortical neuroplasticity as revealed by functional magnetic resonance imaging (fMRI) [1]. The heterogeneity of scotomas renders standard random effects group analysis [2] inadequate. In this particular case we do not expect a general effect [3] in visual cortex during improvement in visual performance, rather we expect an effect on average. This is due to the fact that certain voxels, for certain subjects will show an effect of an improvement in visual performance in certain parts of the visual field. Here we introduce a new method of modeling scotomas in fMRI, to reveal a clearer pattern of neuroplasticity, across a heterogeneous patient-population.

2462. Group Analysis Reproducibility of Block and Event-Related FMRI Designs Using Language Tasks Francois Lazeyras1, Mohamed L. Seghier, 12, Stephane Simon3, Alan J. Pegna4, Khateb Asaid4 1University Hospital of Geneva, Geneva, Switzerland; 2Institute of Neurology, UCL, London, UK; 3University of Geneva, Geneva, Switzerland; 4Neurology, University Hospital of Geneva, Geneva, Switzerland

We investigated the reproducibility of normative fMRI maps using block and event-related paradigms in 12 volunteers in two visits separated by 3 months. We used a conjunction analysis to determine the common activation between the 2 sessions. The primary language regions were highly reproducible across sessions. In term of region size, roughly 40% of the voxels in these language regions were common in both sessions. Finally, the lateralisation index was very reproducible in the block paradigm, somewhat less in the event-related approach reflecting more involvements of the right hemisphere. In conclusion, both language paradigms are adequate for reliable clinical investigations.

Poster Sessions

406

2463. Blind Removal of Gradient Noise from Overt Participant Speech During FMRI Matthew D. Kleffner1, Ian C. Atkinson2, Douglas L. Jones1 1University of Illinois at Urbana-Champaign, Urbana, Illinois, USA; 2University of Illinois at Chicago, Chicago, Illinois, USA

Interpretation of overt participant speech (50-70 dBA) functional MRI (fMRI) is made difficult due to significant acoustic noise produced during image acquisition (>100 dBA). Removing this noise while preserving the speech is challenging, in part because mouth movement alters the noise recorded by microphones placed close to the mouth. A recently-developed blind, multi-microphone speech-enhancement algorithm is robust to speaker position, reverberation, and noise. This technique is applied to overt speech recorded during fMRI to suppress the gradient noise without distorting the desired speech signal. Estimated signal-to-noise ratio (SNR) gains of 20-27 dB are achieved from multiple microphone configurations.

fMRI: Signal Variation & Noise Hall D Wednesday 13:30-15:30

2464. Is T2* Always the Optimum Echo Time in BOLD FMRI? Challenging a Common Concept with a New Contrast to Noise Ratio BOLD Model Pierre-Francois Van de Moortele1, Kamil Ugurbil, 12, Stephane Lehericy, 13 1University of Minnesota, Minneapolis, Minnesota, USA; 2Max Planck Institute for Biological Cybernetics, Tuebingen, Germany; 3CENIR, INSERM U610, University Paris 6, Paris, France

It is generally accepted that BOLD activation peaks at TE=T2*. Thus, matching TE with T2* should improve activation detection. This concept, however, has been challenged by studies where similar fMRI activation detection was obtained at different TE's and it has been shown that a large noise fraction in fMRI series has physiological origins. We propose a new model for BOLD Contrast to Noise Ratio (CNR) which accounts for heterogeneous sources of noise. This model predicts that BOLD CNR varies slowly with TE and that optimal TE can be longer than T2*. Those findings may significantly impact BOLD fMRI acquisition parameters.

2465. Physiological Noise in Gradient Echo and Spin Echo EPI Using Multi-Channel Array Coils Christina Triantafyllou1, 2, Jonathan R. Polimeni3, Lawrence L. Wald3 1Athinoula A. Martinos Imaging Center, McGovern Institute for Brain Research, MIT,, Cambridge, Massachusetts, USA; 2Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, MGH , Charlestown, Massachusetts, USA; 3Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, MGH, Charlestown, Massachusetts, USA

We evaluate the physiological noise in both GRE and SE single-shot EPI time series by comparing temporal to thermal SNR (tSNR and SNR0). We modulate the SNR0 by using different flip angles as well as single channel and multiple channel coils. Our findings suggest that the relationship between tSNR and SNR0 can be well parameterized by the Krueger model for both SE and GRE time-series and for array data, with 20% difference in &#61548; for GRE and SE. This suggests that when SNR0 is modulated in this way, the SE physiological noise can be modeled as proportional to the signal.

2466. Retrospective Estimation and Correction of Long-Term Physiological Effects in FMRI Jaemin Shin1, Richard Cameron Craddock2, Xiaoping Hu1 1Georgia Tech / Emory Univ, Atlanta, Georgia, USA; 2Georgia Tech, Atlanta, Georgia, USA

Low-frequency fluctuations in the cardiac rate and the depth and the rate of breathing have been identified as a significant source of low-frequency (<0.1 Hz) fluctuations in the BOLD signal. In this study, we estimate these low-frequency physiological fluctuations, pixel-by-pixel from BOLD timecourse by estimating the impulse responses of physiological processes, and correct these signal changes. The correlations between the resting-state fMRI timecourses and 7, and 12 sec delayed respiration volume changes are substantially reduced by this approach. In the grey matter, the fraction of standard deviation (SD) in the original timecourse accounted for by physiological fluctuations was 28.09% for respiration and 12.49% for heart beat. These results indicate that our method is effective for removing physiology-induced low frequency fluctuation, which is significant in fMRI data.

2467. Efficient Correction for Artificial Signal Fluctuations in Resting-State FMRI-Data Andreas Weissenbacher1, Christian Windischberger1, Rupert Lanzenberger, Ewald Moser1 1Medical University of Vienna, Vienna, Austria

Spontaneous low frequency fluctuations in the brain that are the basis for functional connectivity analysis are overlaid with various other signals originating from residual motion artifacts, respiration and cardiac action. Here we suggest an automated correction approach using multiple linear regression methodology to compensate the effects of non-neural-related signal changes, including global, ventricle and white matter signal, as well as residual motion. Based on data from 40 healthy subjects we show that the proposed method greatly improves the specificity of functional connectivity analysis results.

2468. An Analysis of the Robustness of the RVT Correction in the Presence of Non-White Noise Processes in FMRI Data Erik B. Beall1, Mark J. Lowe1 1Cleveland Clinic, Cleveland, Ohio, USA

Respiratory variation is believed to produce significant variation in fMRI timeseries data, and in particular affect resting state connectivity analyses. The RVT (respiratory variation over time) correction is a proposed method of dealing with the problem. However, the RVT delay searching process may produce incorrect lags in the presence of non-white noise. We show detected RVT delay in simulation that are incompatible with injected RVT delay and delays incompatible with the physiologic theory of RVT in fMRI data.

Poster Sessions

407

2469. Reducing Physiological Noise in FMRI Using Simultaneous Echo Refocusing Sequence with 8 Slices (SER-8) Suk-tak Chan1, 2, Timothy G. Reese2, Kenneth K. Kwong2 1The Hong Kong Polytechnic University, Hunghom, Hong Kong; 2Massachusetts General Hospital, Charlestown, Massachusetts, USA

Cardiac and respiratory pulsations are the bane of fMRI brain studies. We extended the Simultaneous Echo Refocusing (SER) EPI sequence from its original 2 slice single-shot acquisition into (SER-8) which can acquire 8 slices at one-shot. We demonstrated how SER-8 with a TR of 150ms can be used to remove physiological noise in brain activation. Cardiac gated imaging, collected all at the same cardiac phase, is another approach to reduce cardiac noise and respiratory noise. Our findings showed that physiological noise can be effectively separated from BOLD images acquired with either short TR or T1-corrected cardiac gated SER-8 sequence.

2470. Adaptive FID-Navigators for Respiration Monitoring in Multi-Slice FMRI Applications Tobias Kober1, 2, Wietske van der Zwaag2, 3, Jose Marques2, 3, Reto Meuli4, Rolf Gruetter2, 5, Gunnar Krueger1 1Siemens Medical Solutions-CIBM, Lausanne, Switzerland; 2Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland; 3University of Lausanne, Lausanne, Switzerland; 4CHUV, Lausanne, Switzerland; 5Universities of Lausanne and Geneva, Switzerland

The sensitivity of task-based and resting state fMRI methods is often limited by respiratory and cardiac fluctuations masking the activation-induced BOLD response. Several correction strategies have been proposed, typically applied either during acquisition or post-processing. We propose a more comprehensive implementation that samples respiration-induced B0-changes using the intrinsic MR-signal. Extending previous implementations, respiration is monitored continuously in multi-slice experiments. This allows simultaneous correction of (a) slice dependent global B0-fluctuations during image reconstruction and (b) residual effects through additional regressor for the fMRI analysis. Results proof the feasibility to acquire fully automatic and user-independent fMRI data of highest quality.

2471. Noise Reduction in FMRI GRE EPI Acquisitions Using Real-Time Navigators Daniel Nicolas Splitthoff1, Oliver Speck, 1, Maxim Zaitsev1 1University Hospital Freiburg, Freiburg, Germany

As is well known, GRE EPI imaging suffers heavily from susceptibility artifacts. When these effects vary with time, this can influence the results of functional imaging experiments. We here present the first results of the application of a recently introduced real-time prospective shim correction method in a volunteer measurement. It is demonstrated that the method decreases significantly the energy in the spectra of unexplained noise in an fMRI experiment, especially in the lower frequency range, corresponding to artifacts induced by motion.

2472. Minimizing the Effect of Body Motion on EPI Time Series by Digital Tuning Frank Q. Ye1, Qing San Xiang2 1National Institutes of Mental Health, NIH, Bethesda, Maryland, USA; 2University of British Columbia, Vancouver, Canada

In fMRI of non-human primates, subjects’ body motion poses a difficult technical challenge. A simple linear model is proposed to approximate the magnet field change induced by the body motion, and a simple digital tuning procedure during image reconstruction is used to restore the motion-affected EPI time series. The method is demonstrated on both phantom and monkey scans.

2473. Preprocessing Pipeline Considerations to Compensate for Paradigm-Related Subject Movement Robert L. Barry1, 2, Joy M. Williams1, L. Martyn Klassen1, Jody C. Culham, Ravi S. Menon1 1Robarts Research Institute, The University of Western Ontario, London, Canada

Functional MRI is sensitive to spatial and temporal perturbations in main magnetic field homogeneity within the brain due to movement outside the imaging field of view. To simulate paradigm-related subject movement, a phantom arm was constructed and moved (creating 6 Hz peak-to-peak spatially varying field inhomogeneities in a mid-axial slice) while subjects performed visual activation experiments. The inclusion of a complex phase regressor after navigator correction resulted in a 10.1% increase in average t-statistics, demonstrating the complementary nature of these techniques to further reduce geometric distortions and precondition data to make them more amenable to the benefits of spatial smoothing.

2474. Physiological Noise Reduction in Spinal FMRI from a Single-Stage, Motion-Compensating GLM Approach Chase R. Figley1, Patrick W. Stroman1 1Queen's University, Kingston, Canada

Recent reports suggest that the sensitivity and specificity of functional magnetic resonance imaging of the spinal cord (spinal fMRI) are reduced by motion of the cord itself. However, because this motion is persistent, it has been proposed that modeling the motion-related confounds and including them in a general linear model (GLM) approach is the most effective and efficient way to increase the sensitivity of spinal fMRI to neuronal function. Therefore, we have developed such an approach, using a single-stage GLM, and quantified the improvements in sensitivity and specificity (compared to uncompensated methods) afforded by this new spinal fMRI analysis method.

2475. Vascular Signal Contributions in MR-Encephalography: Direct Observation of Intra- And Extravascular ECG-Pulsatility Benjamin Zahneisen1, Thimo Grotz1, Jürgen Hennig1 1University Hospital Freiburg, Freiburg, Germany

MR-Encephalography is an extremely fast technique to monitor physiological changes by use of simultaneous readout with multiple small RF-coils. A sampling rate far below breathing and ECG frequencies allows for a very accurate determination of the BOLD response. Aim of this work was to separate blood flow related contributions of the BOLD signal from those of tissue and to investigate the influence of blood flow on the physiological noise caused by ECG pulsatility. It is demonstrated that the suppression of intravascular signal reduces the average BOLD amplitude by approximately 40%. Our results show that significant ECG pulsatility persists even when intravascular signal contributions are removed.

Poster Sessions

408

2476. Assessment of Signal Variations in EPI, Induced by Breathing and Hardware Instabilities Daniel Nicolas Splitthoff1, Jürgen Hennig1, Maxim Zaitsev1 1University Hospital Freiburg, Freiburg, Germany

Many approaches have been suggested for correcting for field inhomogeneities in GRE EPI measurements. To our knowledge, however, none of them has investigated on the typical effects of inhomogeneities induced by physiological noise and hardware instabilities. We here determine the order of typical field changes at 3T in phantom and volunteer measurements over a time frame of 5min and present the means to assess their effects. It will be shown, that for bigger matrix sizes the effect of breathing might not be negligible for fMRI measurements.

2477. The Effect of Physiological Noise on FMRI Phase Time Series Gisela E. Hagberg1, Marta Bianciardi2, Valentina Brainovich1, Antonio Cassarà3, Bruno Maraviglia3 1Santa Lucia Foundation, Rome, Italy; 2NIH, Bethesda, Maryland, USA; 3University “La Sapienza”, Rome, Italy

Recently the possibility to use both magnitude and phase time-series for the statistical evaluation of fMRI studies has been proposed, with the prospective of increasing both statistical power and spatial specificity of the activation maps. In order to fully take advantage of the additional information in phase images, knowledge regarding available phase stability is needed. Here we propose and investigate three models for the phase stability at 3T, each model being dependent on the relation between the effect of physiological noise on magnitude and phase variations.

fMRI Analysis Methods Hall D Thursday 13:30-15:30

2478. Using Local Field Potential Information Instead of the Block Design Model for BOLD Analysis Joanna K. Huttunen1, Lauri Lehto1, Antti M. Airaksinen1, Markku Penttonen2, Olli Gröhn1 1University of Kuopio, Kuopio, Finland; 2University of Jyväskylä, Jyväskylä, Finland

Simultaneous local field potential and functional magnetic resonance imaging measurements provide unique premise to use the information measured directly from the brain as the model of the BOLD signal in fMRI analysis. Conventionally the block design model has been used in BOLD analysis. In this study we made the model by using the simultaneously measured LFP signal. In most cases, the LFP model predicts the activation in the somatosensory cortex of a rat similarly to the block design model, but the LFP model predicts the activation in all cases when no activation was detected with the block design model.

2479. MDL-Based Estimation of the Hemodynamic Response Function for FMRI Data Negar Bazargani1, Aria Nosratinia1 1University of Texas at Dallas, Richardson, USA

We propose a method based on the minimum description length (MDL) principle to estimate the hemodynamic response function (HRF) from fMRI data. The proposed method provides a nonparametric approach to HRF estimation without any explicit assumptions. The simulation results show the ability of the MDL-based algorithm to estimate the benchmark HRF with good precision. The statistical analysis with the estimated HRF shows better estimates of the t-statistics compared with that from fixed HRF models. Also, the HRF variability can be captured by this method.

2480. Comparison of Linear Parametric Models for Predicting fMRI Response Parina J. Gandhi1, Bharat B. Biswal1 1UMDNJ, Newark, New Jersey, USA

The purpose of this study was to compare different parametric models and in particular their ability to predict the fMRI response. The transfer function for each voxel depends upon the complex interactions among neurons, underlying hemodynamic function and the task. However, the linear transform model may vary on a voxel by voxel basis. The noise also plays an important role in predicting the stimulated response. This helps in understanding the underlying neuronal activity of the brain. Investigators have tried to predict the fMRI response using linear-time invariant (LTI) techniques. In a LTI system, an output can be determined by convolving the input with the transfer function. Boynton and colleagues [1] characterized LTI relationship between fMRI and neural activity. In a similar study, Glover [2] measured the temporal characteristics of the BOLD response in sensorimotor and auditory cortices while stimuli were presented that varied between durations of 167 msec to 16 seconds. Cohen [3] used a gamma-variate model to fit the impulse response function with the behavioral conditions to obtain a better prediction of the fMRI response.

2481. Sparse Decoding in FMRI Jongho Lee1, Masaki Fukunaga1, Marta Bianciardi1, Jacco de Zwart1, Peter van Gelderen1, Jeff H. Duyn1 1National Institute of Health, Bethesda, Maryland, USA

Under the assumption of sparsity, fMRI data are decomposed into several sources. The resulting sources show good correspondences with the task pattern and the resting-state maps.

2482. A Multivariate Approach to FMRI-Based Subject Discrimination Jeff John Fortuna1, 2, Michael D. Noseworthy1, 2, Adrian Matthew Yuri Koziak2, John MacGregor1 1McMaster University, Hamilton, Canada; 2Brain-Body Institute, Hamilton, Canada

A novel multivariate approach to between-subject fMRI analysis based on multi-way linear algebra and PCA is presented. The approach was compared to a traditional linear regression analysis applied to an experiment which attempted to discriminate between male and female responses to images of human faces. The three spatial, one temporal and one subject dimensions of the fMRI data was collapsed into a two-dimensional data matrix (each row was a spatiotemporal representation of each subject). PCA was used to provide a two-dimensional representation of each subject. In this space, male and female subjects were grouped sufficiently to be linearly separable.

Poster Sessions

409

2483. Detecting Outliers in FMRI Studies with Small Sample Size Rutuparna Sarangi1, Samata M. Kakkad1, Bharat B. Biswal, 1 1UMDNJ, Newark, New Jersey, USA

The purpose of this study was to develop a method to detect outliers for smaller subject populations. In most of the fMRI experiments conducted, one assumes that the variations among subjects are minimal and that the resulting errors are random and Gaussian in nature. However, the data sets used in fMRI are small (usually less than 20 subjects) and cannot be easily determined as fitting the Gaussian model. Besides, increasing the risk of errors in the measurement of the distribution parameters, there is a possibility that the distribution which is being modeled is not the correct distribution. In the case of an outlier, there is no immediate way to differentiate between outliers and normal data points. The outliers can either increase or decrease the “mean” averages. To compensate for this, the subject population usually associated with the fMRI experiments (15-20 subjects) can be increased (80 or more subjects) to make it easier to detect outliers and give a more accurate resampling data sets. In addition to being expensive due to increased scanning time, and other subject related costs, for certain patient populations, it is not possible to increase the sample size to 80 or 100. In this paper, we present a method for detecting outliers in small sample sizes.

2484. An Improved Algorithm for Data Reduction Prior to Independent Component Analysis of Functional MRI Data in the Presence of Colored Noise and Low Source Signal-To-Noise Ratio Vincent Jerome Schmithorst1, Scott Kerry Holland1 1Children's Hospital Medical Center, Cincinnati, Ohio, USA

Data reduction (usually performed via Principal Component Analysis, PCA) and accurate model order estimation are necessary for accurate blind-source-separation in noisy data, performed via a method such as Independent Component Analysis (ICA). PCA assumes white noise while noise in fMRI data can have significant temporal autocorrelation. A data reduction method has been previously published which uses an AR(1) model of the noise. However, the method significantly underestimates the model order at low SNR. We modify the technique for accurate estimation of the model order and extraction of the source subspace in the presence of colored noise and low source SNR.

2485. Identification of Brain Image Biomarkers by Optimized Selection of Multimodal Independent Components Rogers Ferreira da Silva1, 2, Vince Daniel Calhoun, 12 1University of New Mexico, Albuquerque, New Mexico, USA; 2The MIND Research Network, Albuquerque, New Mexico, USA

This study is a segment of a broad research on the analysis of multimodal datasets for the investigation of mental illness and brain diseases. It is dedicated to the use of a data fusion analysis method popular in the neuroscience community called joint independent component analysis (jICA) which has been shown to be able to reveal hidden ‘cross’-information lying within heterogeneous datasets. Our specific goal is the use of an optimization factor based on the distributions of the independent components obtained from jICA to select the (set of) component(s) that mostly discriminates groups of individuals.

2486. Classification of ICA FMRI Data Using Suppot Vector Machines Xuelin Cui1, Michael Cole2, Linda Chang3, Thomas Ernst3, Benjamin Stokes3, Victor Andrew Stenger3 1Univeristy of Hawaii, Manoa, Honolulu, Hawaii, USA; 2John A. Burns School of Medicine, University of Hawaii, Manoa, Honolulu, Hawaii, USA; 3John A. Burns School of Medicine, Univeristy of Hawaii.Manoa, Honolulu, Hawaii, USA

Independent component analysis (ICA) of fMRI data is of current interest because it is data driven [1], requiring no a priori activation model. Unfortunately, visual inspection is still the most common way of determining meaningful IC¡¯s. Several techniques have been proposed to automatically classify IC¡¯s in fMRI [2]. In this work a technique based on 3D discrete wavelet transform (3DDWT) compression and support vector machine (SVM) classifiers is presented. We found that this approach could successfully classify IC¡¯s in a block-designed fMRI experiment at 3T.

2487. Fuzzy Clustering on FMRI Responses Using Autocorrelation Function Features Cheng-Chieh Cheng1, Fu-Nien Wang2, Hsiao-Wen Chung1 1National Taiwan University, Taipei, Taiwan; 2National Tsing Hua University, Hsinchu, Taiwan

In fMRI analysis, data-driven methods are taken to generate the activation patterns, while dimension reduction strategies must be applied to overcome the high computational complexity. Autocorrelation function (ACF) is commonly used to exclude possibly inactive voxels, however, features of the ACF contain important information of signal as well as noise. Thus, we proposed to use the features in the ACF domain not only to differentiate signal and noise, but also to summarize different signal sources. After applying fuzzy C-means algorithm for clustering, averaged time courses (ATCs) are generated to be our activation patterns. In our study, very high correlation (>0.8) between the original data and ATCs is represented.

2488. Bayesian Variable Selection in FMRI Bradley McEvoy1, Rajesh Nandy1 1UCLA, Los Angeles, California , USA

The classical analysis of fMRI data is characterized by a two step process-a statistical model and a thresholding process. This paradigm, though informative, performs these steps as independent processes. In other words, the statistical model is run independent of the thresholding process. We propose to unite these steps under one coherent framework. We achieve this by exploiting characteristics of the Bayesian variable selection technique Stochastic Search Variable Selection (SSVS). The appeal of this framework is it permits the inclusion of prior information on hypothesized effect and avoids sensitivity and specificity issues introduced by the thresholding.

2489. Detection of Spinal Activation of Rat Using Generalized Likelihood Ratio Tests Qiong Zhang1, Cheryl McCreary, Dave Kirk, Foniok Tadeusz, MIchael Smith1, Jeff Dunn 1University of Calgary, Calgary, Canada

To improve the detection of activation in spinal fMRI, the generalized likelihood ratio tests (GLRT) method based on the general linear model (GLM) was applied in this study. The GLRT method with a modified hemodynamic response function was applied to magnitude spinal fMRI data on Gaussian distribution and Rician distribution respectively.The results show that the GLRT method with HRF could detect the activation regions with higher detection rate than Student-t test in the Gaussian case.

Poster Sessions

410

2490. Modeling of Phase Changes in BOLD FMR Zhaomei Feng1, 2, Arvind Caprihan1, Kraston Blagoev, Fuqiang Zhao, Vince D. Calhoun1, 2 1The MIND Institute, Albuquerque, New Mexico, USA; 2University of New Mexico, Albuquerque, New Mexico, USA

In order to better elucidate the source of the phase changes of BOLD fMRI in humans, simulations based on the theory of the Lorentz sphere are performed to model effects of volume-averaged magnetization and demagnetization. The phase model is applied to gradient-echo BOLD fMRI data collected from 16 human subjects during finger tapping experiments at 3 Tesla and preprocessed using the SPM5. The modeled phase change matches the experimentally observed phase change pattern. The agreement is true for all of the subjects studied. Further studies which include the effects of diffusion and large vessels are needed to refine the model.

2491. Separating BOLD Activation from Stimulus-Correlated Motion by Means of Linear Source Extraction Applied to Multi-Echo Data Pieter François Buur1, Christian Wolfgang Hesse1, David Gordon Norris1 1F.C. Donders Centre for Cognitive Neuroimaging, Nijmegen, Netherlands

A novel method is presented that seeks to separate the R2* and S0 signal components in multi-echo fMRI data. The method makes no explicit assumptions about activation time-course or location and is based on a simple linear mixing model of how the sources R2* and S0 project onto the measured data. Using a paradigm where functional activation and subject motion occur simultaneously, succesful extraction of the two sources is achieved. As in principle, all physical processes that give rise to changes in S0 can be separated from those in R2*, the approach also holds promise to reduce e.g. physiological fluctuations.

phMRI Hall D Monday 14:00-16:00

2492. Cerebral Response to Electrical Stimulation at the Different Anesthetic Intervals: An FMRI Study Xiao-yun Fu1, 2, Tian Yu1, Peng Xie1, 2, Ye Tu1, 3, Su lui2, Huafu Cheng4, Ti-jiang Zhang2, Xiao-Qi Huang2, Qi-yong Gong2, 5 1Zunyi Medical Collge, Zunyi, People's Republic of China; 2Huaxi Hospital,Sichuan University, Chengdu, People's Republic of China; 3 Huaxi Hospital,Sichuan University, Chengdu, People's Republic of China; 4University of Electronic Science and Technology, Chengdu, People's Republic of China; 5University of Liverpool, London, UK

It is still unclear how anesthesia affects such cerebral function during pain processing. Our study aims to investigate functional imaging of brain responses to electrical stimulation in rats at different anesthetic intervals. Our results show that incidence and amplitude of activation in the brain vary across the sequential anesthetic intervals The fuctional MRI can therefore provide further evidence for brain processing of nociceptive stimulation at the various anesthetic intervals. It is likely that increasing incidence and amplitude of activation indicates decreased anesthetic depth. Further study is necessary to clarify the relationship between activation map of brain and anesthetic depth.

2493. A Comparison of Alpha-Chloralose and Propofol as Anaesthetic Regimes for BOLD-FMRI Nachiket Abhay Nadkarni1, Benito de Celis Alonso2, Jimmy David Bell1 1Hammersmith Hospital, Imperial College London, London, UK; 2Kings College London, London, UK

Most pre-clinical BOLD-fMRI protocols use anaesthesia with the terminal agent alpha-chloralose. This study investigated the use of propofol anaesthesia instead from which recovery is possible- a crucial advantage for many studies. Using a whisker movement stimulation protocol at 9.4 T, we observed a reduced BOLD response under propofol anaesthesia compared to alpha-chloralose (0.49±0.2% vs. 0.91±0.2% signal intensity change, 19.5±8 vs. 130±47 voxels extent size, threshold p<0.05). This reduction agrees with previous observations using propofol for BOLD-fMRI. However, the attenuation of response is an acceptable compromise for studies where recovery is essential.

2494. Levo-Tetrahydropalmatine Modulates Activities in Dopaminergic Circuits of Naïve Rat Brain Xiping Liu1, Zheng Yang2, Jun Xie1, Qian Yin1, Shi-Jiang Li1 1Medical College of Wisconsin, Milwaukee, USA; 2Beijing Institute of Basic Medical Science, Beijing, People's Republic of China

L- tetrahydropalmatine (l-THP), a D1, D2 receptor antagonist purified from traditional Chinese herb Stephanie [1], has long been used as an analgesic and anti-anxiety agent in China. Recent study has demonstrated that l-THP can significantly attenuate heroin craving and relapse in heroin addicts [2]. Animal behavior experiments also demonstrated this compound can inhibit cocaine’s rewarding effect in terms of self-administration, reinstatement, and brain stimulation reward [3]. Being such a promising treatment for addiction, the baseline action sites and neuronal effect of l-THP, however, have yet to be fully understood. To further understand neuropharmacological mechanisms of l-THP, here, we employed high-field pharmacological MRI (phMRI) to detect activation induced by acute l-THP administration in naïve rat brain.

2495. Remifentanil-Induced Activation Pattern in Rat Brain Detected with PhMRI and Independent Component Analysis Wim Otte1, Jan M. van Ree2, Kajo van der Marel1, Annette van der Toorn1, Rick M. Dijkhuizen1 1Image Sciences Institute, Utrecht, Netherlands; 2Rudolf Magnus Institute of Neuroscience, Utrecht, Netherlands

Analysis of phMRI data is often complicated by lack of knowledge about thepharmacological activation model. We have applied a model-freeprobabilistic independent component analysis to assess a pharmacologicalstimulation paradigm in rats that received repetitive injections withincreasing dose of the µ-opioid receptor agonist remifentanil, with orwithout prior administration of its antagonist naloxone. Our analysisdemonstrated significant remifentanil-induced BOLD responses insubcortical regions. The spatial activation pattern was unaffected bynaloxone pretreatment, which blocked the activation responses to the firstlower doses of remifentanil. This model-free analysis demonstrates itspotential for phMRI studies with complex drug adminstration patterns.

Poster Sessions

411

2496. CBV FMRI in Conscious Animals Using USPIO: Development of a Tool for Measuring Pharmacodynamic Activity in Drug Development Denise C. Welsh1, Alexandre Coimbra1, Fuqiang Zhao1, Mangay Williams1, Richard Hargreaves1, Donald S. Williams1 1Merck & Co.,Inc, West Point, Pennsylvania, USA

The ability to assess drug-induced cerebral activity in awake animals allows investigation of neurologic processes under true physiologic conditions, and provides more clinically relevant information during the drug development process. In conscious animals, we benchmark CBV changes elicited by administration of the carbonic anhydrase inhibitor, acetazolamide(ACZ), and compare it to isoflurane-anesthetized rats. Improved sensitivity is achieved with USPIO and washout signal changes have successfully been detrended. ACZ administration produces a greater CBV response in awake animals compared to anesthetized animals. Thus, conducting fMRI in conscious animals may allow for an increased dynamic range to detect small stimulus-induced changes in activity.

2497. Systemic Infection Alters 5-HT Function in the Rodent Brain as Demonstrated by PhMRI Josephine Raley1, 2, Andrew E. Davis1, Trevor Sharp1, Daniel C. Anthony1, Nicola R. Sibson1 1University of Oxford, Oxford, UK

It is well established that the neurotransmitter 5-hydroxytryptamine (5-HT) is important in key brain functions such as mood regulation, cognition, sleep and pain processing. Furthermore, dysfunction of the 5-HT system has been implicated in the pathophysiology and treatment of a range of psychiatric disorders including major depression. Here we show that activation of 5-HT2A receptors mediates BOLD responses induced by the 5-HT-releasing agent fenfluramine, and that a systemic inflammatory response can markedly alter 5HT function in the brain. Our findings strongly support a role for peripheral infection in the pathogenesis of mood disorders associated with the 5-HT system.

2498. Early Life Stress Impairs Serotonergic Neurotransmission Specifically in the Prefrontal Cortex Revealed by Pharmacological FMRI in Mice Florence Razoux*1, Holger Russig*1, Thomas Mueggler1, Christof Baltes1, Isabelle M. Mansuy1, Markus Rudin1, 2 1University & ETH Zurich, Zurich, Switzerland; 2University Zurich, Zurich, Switzerland

Early life stress is a risk factor of depression. We are investigating the role of serotonergic neurotransmission in this transition using fMRI in a mouse model of early life stress (MSUS) by analyzing changes in cerebral blood volume (CBV) after injection of a 5HT1A receptor agonist. In MSUS and control mice, a decrease in CBV was detected in regions with 5-HT1A receptor expression. The decrease in the prefrontal cortex was significantly lower in MSUS than in control mice. Cross-correlation of 30 brain areas further identified subcortical structures with large differences in inter-regional correlation between the MSUS and control mice.

2499. Changes in BOLD Signaling Induced by Local Chemical Activation of the Dorsal Midbrain in Rats Jason Berwick1, Aneurin Kennerley1, Christopher Martin1, Myles Jones1, Luke Boorman1, Ying Zheng1, John Mayhew1, Peter Redgrave1 1University of Sheffield, Sheffield, UK

In human brain imaging studies, it is rarely possible to explore the consequences of direct manipulations of relevant circuitry. The purpose of the present study was, therefore, to establish technology and procedures for measuring the effects of direct, local chemical stimulation of the brain with fMRI. Using an established model of subcortical visual processing the present study demonstrated that regional changes in neural responses to light stimuli evoked by local chemical stimulation of the midbrain superior colliculus can be measured with fMRI.

2500. Mechanisms of a Negative BOLD Response to Acute Cocaine Administration in Rat Brain Junfang Xian1, 2, Gaohong Wu2, Qian Yin2, Zhilin Wu2, Chunming Xie2, Xiping Liu2, Shi-Jiang Li2 1Beijing Tongren Hospital, Capital Medical University, Beijing, People's Republic of China; 2Medical College of Wisconsin, Milwaukee, USA

The negative BOLD responses after systemic administration of cocaine have been reported, but the detailed mechanisms remain unclear. We observed significant negative BOLD signals, large vessel dilation in the rat brain and significant MABP decrease after cocaine administration during the transient period of the negative BOLD signal. Further, a significant correlation existed between the changes in the negative BOLD and the changes in the vessel size. In conclusion, our results demonstrated that the transient negative BOLD signals could result from cocaine-induced dilation of large vessel in the rat brain observed by using high-resolution fMRI study at high field strength.

fMRI: Cognition & Other Non-Clinical Applications Hall D Tuesday 13:30-15:30

2501. Successful FMRI of the Hypothalamus at 3T Martin Fürsatz1, 2, Christian Windischberger1, Karl Ægir Karlsson2, Ewald Moser1 1Medical University of Vienna, Vienna, Austria; 2Reykjavik University, Reykjavik, Iceland

High field functional magnetic resonance imaging (fMRI) at 3T specifically optimized for ventral brain was used to assess whether emotional stimuli may trigger activation in the hypothalamus in healthy subjects. Random-effects analysis for significant activation differences between stimuli of different emotional content was performed, and parameter estimates from the hypothalamic activation peak were extracted. Thereby it could be shown for the first time that hypothalamus activation is strongly modulated by emotional valence. In concordance with clinical evidence showing that sudden happy arousal may trigger narcoleptic attacks, our results support the theory that narcoleptic episodes are indeed initiated by hypothalamic activity.

Poster Sessions

412

2502. The Role of Middle Temporal and Medial Prefrontal Cortex in Representational Momentum: A FMRI Study Xin Di1, Yulong Ding1, Zhe Qu1, Binbin Ye1, Dingguo Gao1, Hengyi Rao1, 2 1Sun Yat-Sen University, Guangzhou, People's Republic of China; 2University of Pennsylvania, Philadelphia, USA

Representational momentum (RM) refers to the memory shift of the final position of a moving target, yet the roles of the middle temporal (MT) and prefrontal cortex in mediating RM are not clear. Using fMRI, we found that MT was equally activated in RM and non-RM tasks compared to fixation baseline, while medial prefrontal cortex (MPFC) was less deactivated for RM than non-RM tasks. Moreover, MPFC activity negatively predicted the amplitude of memory shifts. These findings support the view that high-level prefrontal cortex rather than low-level motion perception MT area plays the key role in mediating RM effect.

2503. Replicability of Memory Task-Induced Brain FMRI Activation Patterns in Older Adults Xiaowei Song1, 2, Ryan D'Arcy1, Steven Beyea1, Chris Bowen1, James Rioux1, Alma Major2, John Fisk3, Kenneth Rockwood, 23 1National Research Council Canada, Halifax, Canada; 2Dalhousie University, Halifax, Canada; 3QEII Health Sciences Centre, Halifax, Canada

This study investigates whether cognitive task-induced brain fMRI activation patterns can be replicated in older adults. The study suggests that properly designed episodic memory encoding and retrieval tasks can generate sufficiently consistent brain fMRI activation patterns in older adults that reflect memory related neural networks. However, considerable variation may exist in the brain activation of older individuals.

2504. Faces We Know: Neural Processing of Parent, Partner and Own Faces Margot J. Taylor1, Marie Arsalidou1, 2, Drew Morris1, Sarah J. Bayless3, Emmanuel Barbeau4 1Hospital for Sick Children, Toronto, Canada; 2York University, Toronto, Canada; 3Winchester University, Winchester, UK; 4CerCo-CNRS, Toulouse, France

Understanding the neural mechanisms for processing personally familiar faces may have important clinical implications, as impairments in face processing are associated with disorders such as schizophrenia and autism spectrum disorders. Functional magnetic resonance imaging (fMRI) was used to examine the neural correlates of personally familiar faces. Ten participants viewed photographs of their parents, partner, own, famous and unfamiliar faces. Data were analyzed using random effects ANOVA and two ROI analyses. Results show anatomical distinctions in processing personally familiar faces and the involvement of both the core visual system and extended systems of emotional, self and other social knowledge processes.

2505. Discrimination of the T-Statistics Correlation Depends on the Qualitative and Quantitative Task Switching - An Application of Dynamic FMRI to Explore the Cognitive Structures Toshiharu Nakai1, Epifanio Bagarinao2, Yoshio Tanaka2, Chikako Nakai3, Masafumi Hiraoka1, Kayako Matsuo1 1National Center for Geriatrics & Gerontology, Ohbu, Japan; 2National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan; 3Toyohashi Sozo University, Toyohashi, Japan

In order to properly discriminate the correlation coefficient (CC) of the t-statistics response function (TRF) among the brain areas, the effect of qualitative and quantitative modulation of task demand on the TRF was investigated. The CCs of the TRF represented the role of the network including left PMD, bilateral SPL and right basal ganglia for real-time processing of body representation and motor selection. The coupling between the right PMD and the motor areas on the left side corresponded to generation of sequential movements. TRF correlation analysis will be potentially useful for systematic characterization of the cognitive structure under various conditions.

2506. The Sequential Involvement of Distinct Portion of Anterior Cingulated Cortex in Different Stages of Decision Making Using Iowa Gambling Task Jae-Jun Lee1, Hui-jin Song1, Ji-Ae Park1, Joo-Hyun Kim1, Seung-Tae Woo1, Hee-Kyung Kim1, Hui-Joong Lee1, Yongmin Chang1 1Kyungpook National University, Daegu, Republic of Korea

The BOLD functional magnetic resonance imaging was used to assess temporal response of neural activation in healthy subject during the Iowa Gambling Task (IGT) which utilizes decisions involving ambiguity and decisions involving risk. This study suggest that the cognitive division of mPFC including dorsal portion of ACC plays major role in ambiguous decision-making and the IGT corresponding to risky decision-making was associated with significant activities within a corticolimbic network strongly implicated in emotion and reinforcement. In addition, our results also suggest that the decision under ambiguity and the decision under risk situation can be further divided into sub-phases based on the neural network involved.

2507. Functional Neuroimaging & Psychology of Parent-Infant Bonding James E. Swain1, James F. Leckman1, Linda C. Mayes1, Ruth Feldman2, Pilyoung Kim1, Robert T. Constable1 1Yale University, New Haven, Connecticut, USA; 2Bar Ilan University, Ramat Gan, Israel

Objective: With childbirth, parents bond with infants using brain circuits for baby-related empathy, reward and obsessive-compulsive thoughts. Methods: We are studying parental attachment in sets of parents: administering interviews and videos to assess parenting and psychology, and performing functional-magnetic-resonance-imaging of parent brains while they attend to own- and other-baby-cries and pictures – with data acquired longitudinally at 2-4 weeks and 3-4 months postpartum. Results: Overall, mothers and fathers activate a stable circuit over the first four months postpartum, including regions that regulate anxiety and social cognitions. However, individual and group differences emerge according to parental gender, experience timing, and parenting measures.

Poster Sessions

413

Ingestion, Drugs & Pain: Effects or fMRI Signed Hall D Wednesday 13:30-15:30

2508. The Enigma of Intermediate and Ventral Spinal Cord Activity with Thermal Sensory Stimulation: a Spinal FMRI Investigation Patrick W. Stroman1, 2, Chase R. Figley1, Niousha Foad Ghazni1, Natalie Kozyrev1 1Queen's University, Kingston, Canada

Neuronal activity in intermediate and ventral regions of the human spinal cord in response to thermal stimulation was investigated. These areas of activity are not known to be associated with sensory responses, yet they are consistently observed with fMRI of the human spinal cord. Thermal stimuli were systematically varied between 15 C and 29 C, as was the order of experiments, during fMRI of the spinal cord and brainstem. Activity in these cervical spinal cord regions depends on the stimulus temperature, and is correlated with activity in brainstem regions involved with the descending modulation of thermal sensation and pain responses.

2509. Gender Differences in Voluntary Micturition Control - An FMRI Study Juergen Baudewig1, Sandra Seseke1, Kai Kallenberg1, Rolf H. Ringert1, Florian Seseke2, Pe Dechent1 1Georg-August-University Goettingen, Goettingen, Germany; 2Martha-Maria Hospital, Halle, Germany

As bladder dysfunction affects patients of both sexes, we wanted to compare the activation of micturition-related brain areas in healthy men and women directly to better prepare the use of fMRI in patients. Previously, we characterized the cerebral network involved and reported for the first time reliable BOLD activations in brainstem in women. Here, we focused on healthy men and were able to identify the same cerebral network including well-localized activations in the periaquaeductal grey as well as in the continence and micturition centre in the pons. In general, the network revealed stronger activation in men compared to women.

2510. The Effects of Exercise on Regional Brain Activation in Response to Smoking Cues During Temporary Abstinence from Smoking Abdelmalek Benattayallah1, Kate Janse Van Rensburg, Tim Hodgson2, Jon Fulford, Adrian Taylor 1University of Exeter, Exter, UK; 2University of Exeter, UK

fMRI studies were undertaken comparing activations areas in somkers with and without exercise, prior to a protocol presenting the images of smoking. Reduction in activation of the orbito-frontal cortex, at the same time as a reduced self-reported craving, may suggest that exercise has the ability to reduce the perceived incentive salience both of the drug and the craving for the drug This is the first study to explore neurobiological mechanisms for how exercise acutely reduces cigarette cravings.

2511. Sildenafil and the Response to Functional and Hypercapnic Activation - A BOLD and VEP Study Christina Kruuse1, 2, Adam Espe Hansen1, Jes Olesen1, Martin Lauritzen1, Henrik BW Larsson1, Egill Rostrup1, 2 1Glostrup Hospital, University of Copenhagen, Denmark; 2Hvidovre Hospital, University of Copenhagen, Denmark

Sildenafil (Viagra), a selective inhibitor of the cGMP-hydrolyzing phosphodiesterase5 enzyme (PDE5), can induce migraine in the absence of immediate changes in cerebral blood flow or cerebral artery diameter. Based on its mechanism of action (blocked clearance of second messenger) Sildenafil may be expected to enhance the local or global vascular response to external stimuli. Due to common second messenger systems enhanced neuronal excitability has also been hypothesised. These hypotheses were tested in the visual system by evaluating the BOLD and VEP responses to checkerboard stimulation during Sildenafil administra-tion. The global vascular response was evaluated in relation to CO2 inhalation.

2512. The Effect of Remifentanil Upon the Conscious Control of Breathing Kyle T S Pattinson1, Ricardo G. Governo2, Elizabeth C. Russell1, Bradley J. MacIntosh2, Imran Ahmad1, Stephen D. Mayhew1, Douglas R. Corfield, Irene Tracey1, Richard G. Wise 1University of Oxford, Oxford, UK; 2University of Oxford, UK

We investigated the effect of remifentanil, a µ-opioid agonist, upon the neural correlates of a voluntary breathing task, a short breath hold. As remifentanil causes a rise in baseline CO2, we used a series of control measures to disentangle global vascular from neuronally mediated effects. We showed reductions in BOLD responses to the control measures, with significantly greater reductions in the BOLD response to the breath hold in the operculum and dorsolateral prefrontal cortex suggesting depression of neuronal activity. This methodology would be appropriate for investigation of other drugs with profound physiological effects that may confound interpretation of BOLD.

2513. Oral Fat Representation in Human Cerebral Cortex Sally Fathy Eldeghaidy1, Luca Marciani1, Tracey Hollowood2, Kay E. Head1, Joanne Hort2, Jason Stokes3, Francis McGlone4, Johanneke Busch5, Andy Taylor2, Robin C. Spiller1, Penny A. Gowland1, Susan T. Francis1 1University of Nottingham, Nottingham, UK; 2University of Nottingham, Leicestershire, UK; 3Unilever Coporate R&D, Colworth, UK; 4Unilever R&D, Wirral, UK; 5Unilever R&D, Vlaardingen, Netherlands

We have mapped the cortical representation of oral fat in iso-viscous fat emulsions using a protocol close to the normal experience of consuming liquid fatty foods. Concurrent recording of EMG during fMRI acquisition allowed identification of the time of swallowing to improve detection of fMRI responses. We have identified for the first time cortical areas correlated with increasing fat concentration using a parametric analysis. Activated areas were (a) taste areas (frontal opercular and anterior insula) (b) areas associated with intraoral somatosensory textural attributes (postcentral gyrus, precentral gyrus, superior parietal cortex), (c) areas representing hedonic properties (dorsolateral prefrontal cortex, thalamus, amygdala).

Poster Sessions

414

2514. A High Fat Meal Has No Direct Effect on the Brain BOLD Response in Young Adults Natalie J. Stein1, 2, Joseph J. Carlson1, Sean C. Forbes, Ronald A. Meyer, Robert W. Wiseman1, Jill M. Slade1 1Michigan State University, East Lansing, Michigan, USA

The hemodynamic response can be altered by vasoactive substances and can therefore affect the blood oxygen level-dependent (BOLD) response in functional MRI that is associated with neuronal activity. Nutrient composition, e.g. a meal high in fat, has been shown to alter vascular function and may therefore also affect the brain BOLD response. In this study, adding fat to a meal did not affect the brain BOLD response in young, healthy adults.

2515. Expertise Modulates the Perception of Pain in Others Kun-Hsien Chou1, Ya-Wei Cheng, Jean Decety, I-Yun Chen, Ching-Po Lin 1Institute of Biomedical Engineering, National Yang-Ming University, Taipei, Taiwan

Perceiving the pain of others activates a large part of the pain matrix in the observer. Since this shared neural representation may lead to empathy or personal distress, regulatory mechanisms must operate in people who inflict painful procedures in their practice with patient populations in order to prevent their distress from impairing their ability to be of assistance. In this fMRI study, physicians who practice acupuncture were compared to naïve participants while observing animated visual stimuli depicting needles being inserted into different body parts. Results indicated that different brain network was activated between control and expert groups

2516. Using Arterial Spin Labeling to Image the Changes in Cerebral Blood Flow Caused by Sustained Muscular Pain Daron Gordon Owen1, 2, Collin Clarke2, Vel Velayutham2, Sugantha Ganapathy2, Frank S. Prato1, 3, Keith S. St. Lawrence1, 2 1Lawson Health Research Institute, London, Canada; 2The University of Western Ontario, London, Canada; 3St. Joseph's Hospital, London, Canada

Most imaging studies of pain have involved superficial stimuli of brief duration, whereas clinical pain is generally prolonged and arises from deep tissues. In this study, arterial spin labeling (ASL) was used to collect images of cerebral blood flow during a 15 min intramuscular infusion of hypertonic saline. The largest CBF increases and decreases occurred during initial 5 min of pain, and generally dissipated over time. This study demonstrated that ASL can be used to track changes in regional CBF that occur during a prolonged clinically relevant pain model.

fMRI Applications Hall D Thursday 13:30-15:30

2517. A High Resolution FMRI Study of Episodic Memory Retrieval at 7T Bing Yao1, Tie-Qiang Li1, James K. Kroger2, Peter van Gelderen1, Jacco de Zwart1, Doerte Spring2, Jeff H. Duyn1 1National Institues of Health, Bethesda, Maryland, USA; 2New Mexico State University, Las Cruces, New Mexico, USA

The process of human memory retrieval was investigated in an event-related fMRI study using a 7T MR scanner. The results provide convinced evidences that both the medial and lateral anterior prefrontal cortex play important role in the memory retrieval process.

2518. Using High-Resolution FMRI to Identify Individual-Specific Speech Motor Regions Satrajit Sujit Ghosh1, Michael Hamm2, Karsten Jahns3, Christina Triantafyllou1, 4 1Massachusetts Institute of Technology, Cambridge, Massachusetts, USA; 2Siemens Medical Solutions, Charlestown, Massachusetts, USA; 3Siemens Medical Solutions, Erlangen, Germany; 4Massachusetts General Hospital, Charlestown, Massachusetts, USA

The experiment aimed to dissociate speech related clusters of activity around ventral pre-motor cortex and the supplementary motor area in individuals. These clusters are difficult to separate using low-resolution scans. We utilized multi-channel phased-array coils to achieve high-resolution fMRI acquisition with 1mm and 2mm isotropic voxel sizes. Using data from a 32-channel coil, our findings demonstrate localization of sulcal bank-specific activity. Compared to a 12-channel head coil, the 32-channel coil provides greater sensitivity and precision to the size and location of brain activity. High-resolution data permits use of small smoothing kernels thus limiting smearing of activity across functionally distinct regions.

2519. Functional Magnetic Resonance Imaging of the Motor Network with 65ms Time Resolution Zoltan Nagy1, Chloe Hutton1, Ralf Deichmann1, 2, Nikolaus Weiskopf1 1University College London, London, UK; 2University of Frankfurt, Frankfurt, Germany

: Functional magnetic resonance imaging (fMRI) is a widely used technique to image brain function. Its limitations include a relatively low time resolution (compared to EEG for example) and that the observed signal changes are related to hemodynamic response to neuronal activity and this response have regional and intersubject variability. We used a data re-ordering technique on an event-related data set to achieve a time series with 65ms time resolution. Based on this dataset we show demonstrate the regional variability of the hemodynamc response. In addition we also observed, region-specific, high-frequency changes in the signal.

2520. Corticothalamic Neuronal Interaction Revealed by Dynamic FMRI Nanyin Zhang1, Xiao-Hong Zhu1, Yi Zhang1, Wei Chen1 1University of Minnesota, Minneapolis, Minnesota, USA

It has recently been suggested that the LGN relay function is not as effective if it is in the ‘burst mode’, compared to the situation when it is in the ‘tonic mode’. In this study, we investigated the corticothalamic interaction using the dynamic fMRI approach. Both V1 and LGN activities are significantly suppressed when the visual system is within the refractory period. However, there is additional reduction in LGN BOLD activity compared to V1. This reduction is presumably induced by corticothalamic feedback. These results suggest that it is feasible to use the dynamic fMRI approach to investigate large-scale neural networks.

Poster Sessions

415

2521. Spinal Cord Functional MRI: Gradient Echo Versus Spin Echo Chris J.C. Bouwman1, 2, Walter H. Backes2 1Eindhoven University of Technology, Eindhoven, Netherlands; 2Maastricht University Hospital, Maastricht, Netherlands

Spin echo and gradient echo pulse sequences for cervical spinal cord fMRI were optimized for signal sensitivity and signal-to-noise characteristics and evaluated for finger motion tasks at 3T field strength. Gradient echo based fMRI appeared more signal sensitive, location-specific and reproducible than spin echo imaging.

2522. Mapping Human Somatosensory Cortex with FMRI at 1 Mm Isotropic Resolution Rosa Maria Sanchez Panchuelo1, Denis Schluppeck1, Sue Francis1, Richard Bowtell1 1University of Nottingham, Nottingham, UK

The increased BOLD contrast to noise ratio available at 7T has been exploited in measuring the topographic representation of the digits of the hand in human somatosensory cortex at 1 mm isotropic resolution in experimental runs of a less than 10 minutes duration. A ‘travelling wave’ paradigm was used and the data analysed using a Fourier-based method, normally employed in retinotopic mapping. Results were displayed on high resolution anatomical images and the inflated somatosensory cortex. Activation was confined to the grey matter strip and clearly showed the expected digit ordering along the postcentral gyrus.

2523. Regularized Localized Parallel EVI: Application to the Study of Habituation Effects in FMRI Cécile Rabrait1, Philippe Ciuciu1, Alejandro Ribés1, Cyril Poupon1, Ghislaine Dehaene-Lambertz1, 2, Patrick Le Roux3, Denis Le Bihan1, Franck Lethimonnier1 1Commissariat à l'Energie Atomique, Gif-sur-Yvette, France; 2INSERM, Gif-sur-Yvette, France; 3GEHC, Buc, France

2D SENSE imaging and field-of-view reduction make Localized Parallel EVI a powerful 3D single-shot acquisition method, which allows the acquisition of relatively large brain volumes at high scanning rates. In this study, temporal SNR was increased due to the optimization of the acquisition parameters and the regularization of parallel reconstruction. The efficiency of the optimized setting has then been demonstrated using a language comprehension task inducing habituation effects. High temporal resolution single-voxel hemodynamic response function have been estimated and their timing properties have been extracted. This new approach could improve the understanding of complex neurovascular mechanisms.

2524. Interaction Between GCBF and RCBF and Normalization of Language BOLD FMR Maps Using Breath Holding Gianpaolo Basso1, Stefano Magon2, Jens Volkmar Schwarzbach1, Manuela Orsini1, Nico Dario Papinutto1 1University of Trento, Mattarello, Tennessee, Italy; 2University of Verona, Verona, Italy

Use of BOLD fMR to explore brain correlates of cognitive functions in humans must face possible confounding due to non-neural BOLD signal modifications. Notably, BOLD signal due to systemic CO2 modulation systemic of global cerebral blood flow (gCBF) could confound interpretations of BOLD signal related to regional cerebral blood flow (rCBF) due to neurovascular coupling. In the present study we found that gCBF modulation due to breath hold and rCBF due to a language task act additively in frontal and temporo-parietal language related areas. On the other hand, vascular reactivity maps obtained with breath hold allowed normalization of spatial variability of cognitive related BOLD maps.

Spine & Bone Hall D Monday 14:00-16:00

2525. Decay from Diffusion in Internal Field (DDIF) and R2* Contrast in Bovine Tibiae Samples at 3 T and 7 T Eric Edward Sigmund1, Edward X. Guo2, Yi-Qiao Song3 1New York University, New York, New York, USA; 2Columbia University, New York, New York, USA; 3Schlumberger-Doll Research, Cambridge, Massachusetts, USA

An in vitro study of 8 mm bovine tibiae trabecular bone (TB) samples was conducted as part of an implementation on clinical scanners of a recently developed TB structural contrast, based on decay due to diffusion in the internal field (DDIF). Both DDIF and R2* contrast were measured in 10 samples, varying in strength by a factor of 10, as a function of field strength (3 T vs. 7 T) and field angle relative to the bone axis. Both contrasts show sensitivity to scale and anisotropy information., and provide valuable data for the optimization of DDIF for in vivo imaging.

2526. MR Imaging at 3T of Trabecular Bone Structure InType 2 Diabetes Patients: Comparison with In-Vivo Micro-CT Markus B. Huber1, Ben Hyun1, Roland Krug1, Umesh Masharani1, Sharmila Majumdar1, Thomas M. Link1 1University of California, San Francisco, San Francisco, USA

Type 2 diabetes patients have elevated bone mineral density (BMD) but an increased risk of fracture of the e.g. hip. To assess the differences in bone quality, we performed high resolution MRI at 3T of the calcaneus, the distal tibia and the distal radius and in-vivo micro-CT imaging of diabetes patients and a age- and BMI-matched control group. We found differences in the trabecular bone structure between the two groups which were very site dependant. We conclude that the general model for fracture risk prediction might not be accurate for type 2 diabetes patients.

2527. In Vivo Trabecular Bone Micro-Imaging at Isotropic Resolution Using 3D FLASE with Parallel Imaging at 3T Jeremy F. Magland1, Michael J. Wald1, Rostislav Lemdiasov2, Felix W. Wehrli1 1University of Pennsylvania Medical Center, Philadelphia, Pennsylvania, USA; 2InsightMRI, LLC., Worcestor, Massachusetts, USA

A modified 3D FLASE pulse sequence tailored for micro-imaging at 3T field strength is shown to be able to generate images in vivo of trabecular bone with 160 µm3 isotropic voxel size at the distal tibia. Unlike past studies that involve highly anisotropic acquisitions (anisotropy factor of 3 or more), the present methodology provides detailed insight into the plate-rod architecture of the trabecular network in all three dimensions. The higher resolution, acquired in 16 minutes scan time, was achieved with a custom-built 4-element phased array in conjunction with partial parallel imaging.

Poster Sessions

416

2528. Image Resolution and SNR in 2D Radial Ultrashort TE Imaging Mark Bydder1, Jiang Du1, Atsushi Takahashi2, Matthew D. Robson3, Graeme Bydder1 1University of California, San Diego, California , USA; 2GE Healthcare, Menlo Park, California , USA; 3Oxford University, UK

The optimal SNR in radial imaging is obtained with a short readout duration. However this also limits the attainable resolution. Various trade-offs of SNR and resolution are considered.

2529. Clinical Evaluation of the Compact MRI System for Trabecular Bone Microstructure Measurements of the Finger Katsumi Kose1, Nachiko Iita1, Shinya Handa1, Kazuki Ohya1, Tomoyuki Haishi2, Masako Ito3 1University of Tsukuba, Tsukuba, Japan; 2MRTechnology Inc., Tsukuba, Japan; 3Nagasaki University, Nagasaki, Japan

A compact MRI system developed for trabecular bone (TB) microstructure measurements was applied to 51 normal subjects and 230 patients to evaluate its clinical efficacy. 3D MR images with 180 microns x 180 microns x 160 microns spatial resolution of 46 normal subjects and 119 patients were successfully acquired with negligible motion blur and used to calculate bone microstructure parameters. The obtained results have suggested that the structure model index (SMI) is the most sensitive parameter to characterize the pathological status of the TB.

2530. Evaluation of the Detection Sensitivity of Simulated Trabecular Bone Loss in μMRI Charles Qingchuan Li1, Jeremy F. Magland1, Chamith S. Rajapakse1, X Edward Guo2, Xiaohui Henry Zhang2, Felix W. Wehrli1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA; 2Columbia University, New York City, New York, USA

Patients suffering from osteoporosis or other osteodegenerative diseases experience loss of trabecular bone mass and structural integrity, leading to a decrease in the overall mechanical strength of the bone. The development of the “virtual bone biopsy” (VBB), a combination of magnetic resonance micro-imaging (μMRI) and digital image processing techniques, has been shown to quantify topology and scale of human trabecular bone noninvasively. Through digital simulation of trabecular bone loss at resolutions and SNR levels typically achievable in clinical μMRI, it is shown that VBB processing techniques are capable of quantifying structural changes caused by two different forms of bone loss.

2531. Optimized Partial Parallel Imaging of Trabecular Bone Microstructure in the Distal Tibia Michael J. Wald1, Jeremy Magland1, Felix W. Wehrli1 1University of Pennsylvania Medical Center, Philadelphia, Pennsylvania, USA

Micro-MRI of trabecular bone requires high resolutions leading to long scan times. At higher fields, the gain in signal to noise can be traded for shorter scan times using partial-parallel imaging. Noise inflation and reconstruction artifacts of partial-parallel imaging can adversely affect the derived structural parameters. In this work, a generalized partial-parallel acquisition (GRAPPA) with multi-column multi-line interpolation (MCMLI) is optimized for the fast large angle spin echo (FLASE) pulse sequence in the distal tibia at 3T for an approximate two-fold acceleration. The optimal acquisition and reconstruction are evaluated using an empirical approach to measuring the signal to noise performance and through measuring the derived structural parameters in both the accelerated and non-accelerated acquisitions.

2532. Magnetic Resonance Microscopy of Collagen Mineralization Ingrid E. Chesnick1, Jeffrey T. Mason1, Naomi Eidelman2, Kimberlee Potter1 1Armed Forces Institute of Pathology Annex, Rockville, Maryland, USA; 2National Institute of Standards & Technology, Gaithersburg, Maryland, USA

A model mineralizing system was subjected to magnetic resonance microscopy (MRM), to study how water proton relaxation times and magnetization transfer ratios (MTR) can be used to monitor the replacement of water around collagen fibrils with mineral. Our model system was mineralized with polymer-stabilized amorphous calcium carbonate. X-ray diffraction data and MRM-derived parameter maps established that the mineralization process can be sub-divided into 3 phases: (i) water displacement by amorphous calcium carbonate, (ii) mineral accretion, and (iii) collagen encapsulation. Our results support the use of MTR as a surrogate measure of collagen mineralization.

2533. Magnetic Resonance Microscopy of a Novel Mineralizing System Ingrid E. Chesnick1, Francis A. Avallone2, Kimberlee Potter1 1Armed Forces Institute of Pathology Annex, Rockville, Maryland, USA; 2Armed Forces Institute of Pathology, Washington, District Of Columbia, USA

We present a novel mineralizing system in which a polymer scaffold is seeded with osteoblasts isolated from chick calvarial bones and the scaffold is implanted onto the allantochorial membrane of a developing chick embryo. Seven days post-implantation there was a notable reduction in the water proton T2 values and a marked increase in water proton MTR values compared to non-implanted controls. These results were attributed to the generation of bone-like tissue within the polymer scaffold, which was later confirmed by fluorescence microscopy. This novel model system can be used to gain further insights into the bone formation process in vivo.

2534. T2*-Relaxometry and 1H-MRS at 3T Applied to Healthy and Osteoporotic Subjects: Preliminary Data Supporting a New Procedure to Evaluate Bone Fracture Risk Silvia Capuani1, 2, Mauro Rebuzzi3, Fabrizio Fasano4, 5, Gisela E. Hagberg4, 6, Marco Di Mario4, Vincenzo Vinicola4, Bruno Maraviglia, 67 1CNR-INFM CRS SOFT, Rome, Italy; 2Enrico Fermi Center, Rome, Italy; 3Physics Dpt Univ. "La Sapienza", Italy; 4IRCCS Santa Lucia Foundation, Rome, Italy; 5CNR-INFM CRS SOFT, Italy; 6Enrico Fermi Center, Italy; 7Univ. "La Sapienza", Rome, Italy

Bone Mineral Density (BMD) accounts only for 60% of the global risk of bone fracture due to the partial information that BMD provides on bone tissue. Other components, such as bone marrow, constitutes principally by lipids and water, are present in spongy bone, and may contribute in determining its resistance to fracture. We evaluated T2* as function of both lipids-water content (from 1H-spectra) and trabecular bone density in calcanei of healthy and osteoporotic subjects to investigate the individual variability which affects T2* measurements. The goal is optimize the procedure based on spongy bone T2*-measurements, to be used in clinical practice.

Poster Sessions

417

2535. Magnetic Resonance Imaging in Murine Spondyloarthropathy: A Longitudinal Study Marleen Verhoye1, 2, Peggy Jacques3, Dirk Elewaut3, Eric Achten4, Nadja Van Camp1, Annemie Van der Linden1 1Bio-Imaging Lab, University of Antwerp, Antwerp, Belgium; 2Vision Lab, University of Antwerp, Belgium; 3Lab. for Molecular Immunology and Inflammation, Dept. of Rheumatology, Ghent University Hospital, Ghent, Belgium; 4Department of Neurology, Department of Radiology and Medical Imaging, Ghent University Hospital, Ghent, Belgium

In vivo longitudinal MRI was used to evaluate the sacroiliac joints in relation to disease duration in a TNF-ÄARE mouse model of SpA. During the course of the disease, MRI demonstrated that the sacroiliac joints become gradually affected. Joint space narrowing can be very well appreciated on T1-weighted images, eventually leading to joint bridging. Furthermore, as compared to controls, both sacrum and iliac bones remain very poorly mineralized (demonstrated by T2-weighted MRI) until 7 months of age. We conclude that in addition to an inflammatory syndrome strongly resembling SpA, chronic TNF exposure also has detrimental effects on normal bone mineralization.

2536. Spinal Versus Whole Body MRI in Patients with Multiple Myeloma and Monoclonal Gammopathy of Undetermined Significance Tobias Baeuerle1, Kerstin Fechtner, Jens Hillengass, Hans-Ulrich Kauczor, Hartmut Goldschmidt, Lars Grenacher, Stefan Delorme 1German Cancer Research Center, Heidelberg, Germany

The aim of our study was to evaluate if a spinal MRI is sufficient for evaluation of patients with newly diagnosed multiple myeloma (MM) and monoclonal gammopathy of undetermined significance (MGUS) or if a whole body MRI is necessary to detect all focal lesions. In 100 patients with MM and MGUS the majority of focal lesions was detected in the extra-axial skeleton which would not have been seen in spinal MRI only. Although spinal MRI is the standard examination in these patients, whole body MRI is needed for detection of focal lesions in patients with newly diagnosed MM and MGUS.

2537. Reproducibility of a Novel 3D Pulse Sequence for Mapping T1ρ in Inter-Vertebral Disc Matthew Fenty1, Walter Witschey1, Chenyang Wang1, Ravinder Reddy, PhD1, John Bruce Kneeland, MD2, Arijitt Borthakur, PhD1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA; 2Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA

We measured the reproducibility of mapping T1ρ with a novel 3D MRI pulse sequence called SLIPS, which is based on the steady-state free precession. We are now able to generate 3D biochemical maps of tissue hydration and proteoglycan content in the discs of the entire lumbar spine in vivo in less than 15 minutes. The total mean coefficient of variation for the study was 10%.

2538. Quantitative Assessment of Normal and Degenerative Intervertebral Discs Using Apparent Diffusion Coefficient with GRAPPA Eito Kozawa1, Waka Mizukoshi2, Youichi Sato2, Naoko Nishi2, Fumiko Kimura2 1Saitama Medical University, 1397-1, Yamane, Hidaka-shi, Japan; 2Saitama Medical University, Japan

We examined 62 subjects with 1.5-T MR imaging units on b factors of 0, 400, and 800 msec of diffusion-weighted images. We divided our subjects into two groups, those normal intervertebral disc and those degenerative intervertebral disc, and we compared the apparent diffusion coefficients (ADC) in the two group. The ADCs of the groups were significantly different according to Mann-Whitney’s U test (P < 0.01). In conclusion, a statistically significant decreased in the ADC values of degenerated lumbar disc compared with the ADC values of normal disc.

2539. Bone Structural Analysis on Different Resolutions in Magnetic Resonance Imaging June-Goo Lee1, 2, Gyunggoo Cho1, Youngkyu Song1, Jee-Hyun Cho1, Jong Hyo Kim2 1Korea Basic Science Institute, Cheongwon, Republic of Korea; 2Seoul National University College of Medicine, Seoul, Republic of Korea

It is known that trabecular bone structure gives additional information to bone mineral density (BMD) in the prediction of bone strength in vitro and in the discrimination of patients with without osteoporotic vertebral and femur fractures. The trabecular bone structure has been studied using MR images. But for in vitro MR imaging, the resolution of the image is limited by scan time. Thus, we developed bone structural analysis program and investigated the effect of different resolutions of magnetic resonance image on the calculation of trabecular bone parameters

Cartilage Hall D Wednesday 13:30-15:30

2540. Stretchable Coil Arrays Enable Knee Imaging at Varying Flexion Angles Jurek Antonin Nordmeyer-Massner1, Nicola De Zanche1, Klaas Paul Pruessmann1 1University and ETH Zurich, Zurich, Switzerland

We present an 8-channel wearable knee coil array whose elements stretch to conform to the subject’s anatomy thus optimizing signal detection for varying knee sizes and flexion angles. The array is made by sewing stretchable conductors onto an elastic fabric that mimics form-fitting clothing. The stretchable design is demonstrated by high-resolution images of the knee at different flexion angles, which were obtained in immediate succession without any rearrangement of the coil array. Promising applications in musculoskeletal MRI include such variable-flexion imaging and time-resolved studies of joint dynamics. Both are not possible with conventional rigid knee coil arrays.

2541. Visualization of Collagen Crimp in Tendon Using High-Field MRI Kelsey Mairead Mountain1, Tadeusz Foniok, Jeff F. Dunn, John Robert Matyas 1University of Calgary, Calgary, Canada

Crimp is a periodic wave-like pattern that is exhibited by a tendon when illuminated with polarized light. This phenomenon is a molecular property of the constituent collagen fibers, playing an important role in tendon physiology as the crimp pattern tends to disappear as strain increases. High-field MRI can detect collagen organization based on changes in T2 relaxation. In this study, collagen crimp was detected in tendon with MRI, and was validated using polarized light microscopy.

Poster Sessions

418

2542. MRI Study of the Repair Tissue Following ACI in the Defect of the Human Cartilage Specimens Zuzana Majdisova1, 2, Pavol Szomolanyi1, 2, Vladimir Juras1, 2, Siegfried Trattnig1 1MR Centre - Highfield MR, Vienna, Austria; 2Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia

Properties of the repair tissue following Autologous Chondrocyte Implantation in human cartilage specimens were evaluated using MR parameters T1, T2 and apparent diffusion coefficient (ADC). Specimens were implanted and nourished under the skin of nude mice for five and eight weeks. After removing from this model environment the MR microimaging was performed using a 3 Tesla scanner. T1, T2 and ADC values of the repair tissue were compared with the normal cartilage values. Lower relative DR1 and ADC values decreasing after longer maturation process predict higher amount of the proteoglycans and an improvement in the repair tissue quality.

2543. A Random Regressor Model for T1-Correction of SPGR Variable Flip-Angle Acquisition Without Experimental B1-Inhomogeneity Correction Burkhard Mädler1, 2, Derek C. Wilson2, 3 1Philips Medical Systems, Vancouver, Canada; 2University of British Columbia, Vancouver, Canada; 3Vancouver Coastal Health, Vancouver, Canada

Quantitative T1-mapping from spoiled gradient recalled echo (SPGR) acquisition with varying flip angles FA allow fast and high resolution T1-quantification in a clinical feasible timeframe. The accuracy of the computed T1-maps from the measured SPGR signal depends strongly on the SNR, number of measurement points and critically from the correct knowledge of FA. Especially at higher field strength calibration of the true FA across the VOI becomes inevitable. Previously introduced methods require additional scan time and if the B1-information was not provided for already performed scans the estimated T1-values might differentiate significantly from the true values. We introduce a novel method of numerically estimating the error of the presumably known FA from the behaviour of the SPGR-signal by means of a orthogonal distance regression (ODR) method. The primer application is for T1-quantification in dGemric (delayed Gd-enhancement of MRI in cartilage) of the knee and hip joints.

2544. Effect of Magnetization Transfer on T1 and T2 Measurements of Articular Cartilage Atsuya Watanabe1, 2, Chris Boesch1, Takayuki Obata3, Toshiyuki Okubo4, Suzanne E. Anderson5 1University of Bern, Bern, Switzerland; 2Teikyo University Chiba Medical Center, Ichihara, Japan; 3National Institute of Radiological Sciences, Chiba, Japan; 4Department of Radiology, Ichihara, Switzerland; 5Department of Diagnostic, Interventional and Paediatric Radiology, Bern, Switzerland

The aim of this study was to investigate inaccuracy of T1 and T2 measurements in cartilage when multislice acquisition is used. We especially focused on the effect of MT on T1 and T2 measurements, with consideration of the resulting feasibility of multislice acquisition for clinical evaluation.Based on the results of this study, we conclude that it will be difficult to adapt multislice acquisition for T1 measurement using FSE-IR methodology for clinical evaluation because of strong MT effects. On the other hand, multislice acquisition for T2 measurement using FSE is thought to be applicable for clinical evaluation.

2545. Measurement of Cartilage Water Content Using T1 and T2 Relaxation Time Measurements Jatta E. Kurkijärvi1, Mikko Nissi1, Jukka S. Jurvelin1, 2, Miika T. Nieminen3, 4 1University of Kuopio, Kuopio, Finland; 2Kuopio University Hospital, Kuopio, Finland; 3Oulu University Hospital, Oulu, Finland; 4University of Oulu, Oulu, Finland

Increase in water content is characteristically related to degenerative changes of articular cartilage. The ability of T1 and T2 relaxation times to reflect water content was studied at 9.4T in bovine cartilage samples extracted from various joint surfaces. The dependence of MR parameters on proteoglycan content was also investigated. Strong correlations (r=0.8) were observed between water content and T1 or T2. Significant dependencies were observed between MR and compositional parameters, suggesting complex interactions between the constituents. Since T2 is also affected by collagen fibril orientation, T1 relaxation time is proposed as the primary surrogate MRI marker for cartilage water content.

2546. Automatic Segmentation of Articular Cartilage from MRI: A Multi-Contrast and Multi-Dimensional Approach Seungbum Koo1, Brian A. Hargreaves1, Thomas P. Andriacchi1, Garry E. Gold1 1Stanford University, Stanford, California , USA

The purpose of this study was to evaluate segmentation of knee articular cartilage automatically from multiple sets of MR images using a SVM, a kernel-based machine learning algorithm. Multiple sets of MR images were taken for a human knee. The bones were automatically pre-prossed. Each pixel in the image could be regarded as a vector with multiple intensity values and a distance (from bone) value. The pixels in the even and odd numbered slices were used for training and testing of a SVM, respectively. The sensitivity and the specificity of the articular cartilage classification result was 93.8% and 99.3%, respectively.

2547. Accuracy of Building a Three-Dimensional Model of a Complex Articular Cartilage Defect from 1.5T MRI Seungbum Koo1, Brian A. Hargreaves1, Garry E. Gold1, Jason L. Dragoo1 1Stanford University, Stanford, California , USA

The purpose of this study was to evaluate the accuracy of MRI for measuring a defect with complex shape involving the articular cartilage and underlying bone by comparing with a laser scanning technique. An articular cartilage defect in an intact cadaveric human knee was MR imaged and was made into a three-dimensional model. The knee was dissected and the defect was lasers scanned to create the gold standdard shape of the defect. Average deviation of the surface of the MRI model from the surface of the laser scan model was 0.4±0.4 (SD) mm.

2548. Quantification of Knee Cartilage in Vivo in the MMT Model of Osteoarthritis in Rats Using MRI Shantanu Dhamija1, Zhiyong Xie1, Susan Bove1, Ping Chiao1, Serguei M. Liachenko1 1Pfizer, Inc., Ann Arbor, Michigan, USA

In this paper, we present a method for quantification of rat knee cartilage in a surgically induced model of osteoarthritis. Rats were imaged at 7T and cartilage volume and average thickness were quantified using specialized image processing algorithms for semi-automatic cartilage segmentation. A statistical method for the selection of the Region of Interest for increased local sensitivity is presented. This method provides a powerful tool for the preclinical assessment of rat cartilage changes and for drug assessment in osteoarthritis.

Poster Sessions

419

2549. MR-Assessment of Load-Influenced Collagen Fiber Orientation of Articular Cartilage Nikita Garnov1, Wilfried Gründer1 1University of Leipzig, Leipzig, Germany

Collagen matrix lends the articular cartilage its form and stability and provides special mechanical properties able to resist loading and shear forces under physiological conditions. It has been shown that the collagen fibers are bent under static pressure. Due to the dependence of MR-intensity on collagen fiber orientation relative to B0, the characteristic changing of load-influenced MR-intensity in T2-weighted images can yield quantitative data about the deformation of collagen ultrastructure under load-bearing conditions. Based on these data, the additional biomechanical properties of cartilage tissue by means of MRI can be estimated.

2550. dGEMRIC in the Presence of Metal: Improving T1 Maps at 3.0T Agnes G. d'Entremont1, Shannon H. Kolind, Burkhard Maedler, David R. Wilson, Alexander L. MacKay 1University of British Columbia, Vancouver, Canada

An important potential application of dGEMRIC is assessing the effect of surgery on cartilage health. However the presence of metal surgical hardware causes distortion of both images and T1 maps. Two approaches were used to reduce metal artifact: saturation recovery (SR) (versus inversion recovery (IR)), and the Metal Artifact Reduction Sequence (MARS). A gadolinium-doped phantom was imaged with and without metal using SR, IR, and MARS. Both the SR approach and MARS reduced metal artifact, with SR causing the greater improvement. Combinations of these two approaches may reduce artifact enough to map cartilage with dGEMRIC with metal near the joint.

2551. Influence of Knee Positions on T2, T2* and DGEMRIC Mapping in Porcine Knee Cartilage Toshiyuki Shiomi1, Takashi Nishii1, Yoshihiro Sakaguchi2, Norinao Matsumoto2, Yuichiro Matsuoka3, Yasuo Hara4, Norimasa Nakamura1, Yo Myoui1, Hideki Yoshikawa1 1Osaka University Medical School, Suita, Japan; 2Matsumoto medical clinic, Japan; 3Institute of Biomedical Research and Innovation, Japan; 4IVTeC Co. Ltd, Japan

Influence of knee positions during MR imaging, such as flexed knee positions, on quantitative MR assessments has been scarcely investigated, even though knee positional change may cause substantial change of intra-articular biomechanical environment or magic angle effect. We examined influence of knee flexed positions on cartilage assessment by T2, T2* and dGEMRIC using cadaver porcine femoral-tibial joints. Our results may suggest that quantitative MR measurements allow intra-articular biomechanical assessment in association with knee flexion, after excluding factors of magic angle effects.

2552. Comparison of T1ρ and T2 Relaxation Times in Articular Cartilage Pavol Szomolányi1, Vladimir Mlynárik2, Siegfried Trattnig1 1Medical University of Vienna, Vienna, Austria; 2Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland

T1ρ and T2 relaxation times measured using a Carr-Purcell-Meiboom-Gill technique with short inter-echo delays were compared in articular cartilage in vitro. It was shown that the mean T1ρ obtained with a spin locking amplitude of 500 Hz was close to T2 obtained with an inter-echo delay of 6.2 ms. Relaxation maps were also similar, which suggests that both relaxation parameters provide analogous information about cartilage pathology.

2553. T2 and T2* Relaxation as a Means to Evaluate Cartilage Repair Tissue - Initial Results Goetz Hannes Welsch1, Timothy Hughes2, Sebastian Quirbach1, Stephan Domayer1, Stefan Marlovits1, Siegfried Trattnig1, Tallal Charles Mamisch3 1Medical University of Vienna, Vienna, Austria; 2Siemens Medical Solutions, Erlangen, Germany; 3University of Berne, Berne, Switzerland

A reported technique to directly visualize cartilage structure is, among others, quantitative T2-mapping. Underlying reliable results, T2*-mapping with its possible short scan time seems to offer a potential alternative. The goal of the presented feasibility study was to use T2* -in the follow-up of cartilage repair procedures and to compare it to established T2-mapping by a multi-echo spin-echo (SE) technique. The use of T2* allows maps to be created in short time frames and with resolutions that allow a detailed zonal analysis of cartilage. Thus T2* besides T2 might be an additional tool in the evaluation of cartilage ultrastructure.

2554. Precision of T2 Relaxation Times in Healthy and Osteoarthritic Human Tibial Cartilage Annie Horng1, José G. Raya1, Juergen Weber1, Sabine Weckbach1, Kathrin Nixdorf1, Maximilian F. Reiser1, Christian Glaser1 1University Hospital Munich, Campus Großhadern, Munich, Germany

T2 relaxation time has high potential as a diagnostic parameter for cartilage. Precision errors of T2 measurements in tibial cartilage were assessed as to date they are only available for patellar cartilage. Precision errors of tibial cartilage T2 were slightly higher than patellar cartilage T2 precision errors, possibly related to smaller tibial cartilage thickness and consecutively increased partial volume effects. T2 precision errors were small compared to reported change in osteoarthritis (up to 180%) suggesting a reasonable discriminatory power of the technique. The data may provide a base for sample size calculations to design longitudinal and cross-sectional trials in osteoarthritis.

2555. A Quantitative Study of Knee Cartilage in Osteoarthritis Using Parallel Imaging Method Jin Zuo1, Xiaojuan Li1, Radu Bolbos1, Thomas Link1, Sharmila Majumdar1 1Univ. of California, San Francisco, San Francisco, California , USA

Several quantitative methods have been proposed to study osteoarthritis (OA). However, it is not clear if these measurements can differentiate OA at different stages. In this study, we measured mean cartilage thickness, T1rho and T2 on severe OA patients, mild OA patients as well as healthy volunteers to investigate if these biomarkers will change accordingly with the severity of OA. The measurements were performed with a newly developed parallel imaging method.

Poster Sessions

420

2556. Comparison of Delayed Gadolinium Enhanced MRI of Cartilage (DGEMRIC) Using Inversion Recovery and Fast T1 Mapping Sequences Tallal C. Mamisch1, M Dudda2, T Hughes3, D Burstein4, Young-Jo Kim5 1University of Bern, Bern, Switzerland; 2Children's Hospital-Boston, Boston, Massachusetts, USA; 3Siemens Medical System, Erlangen, Germany; 4Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA; 5Chidren's Hospital-Boston, Boston, Massachusetts, USA

Fast T1 mapping technique for delayed Gadolinium Enhanced MRI of Cartilage (dGEMRIC) was implemented for the hip. The fast T1 mapping technique was validated against inversion recovery technique using phantom and clinical studies.

2557. Inter-Scanner Variability of MRI-Based Tibial Cartilage Volumetric Parameters at 1.5T and 3T Annie Horng1, Sabine Weckbach1, Mike Notohamiprodjo1, Christina Muenkel1, Juergen Weber1, Maximilian F. Reiser1, Christian Glaser1 1University Hospital Munich, Campus Großhadern, Munich, Germany

Knowing of slow cartilage loss of 0-5% per year and in view of multicentre studies, inter-scanner variability of MRI-based cartilage volumetric parameters in different scanner types of one manufacturer were evaluated. The results indicate good interscanner agreement at 1.5T and between 1.5T and 3T for all assessed volumetric parameters. In average, differences of 5% have to be taken into account when comparing data from different scanners of one manufacturer. These compare favorably to reported inter-company scanner differences as well as reported differences between scanners of different magnetic field strength. The data may contribute to calculate sample size in multicentric studies.

2558. Accuracy and Precision of Cartilage T2-Relaxation Time Quantification: Impact of the Fit Method Jose G. Raya1, Olaf Dietrich1, Annie Horng1, Jürgen Weber1, Julia Dinges1, Maximilian Felix Reiser1, Christian Glaser1 1Ludwig Maximilian University of Munich, Munich, Germany

The low T2 times in articular cartilage and the high resolution necessary to resolve the cartilage layers unavoidably result in low-SNR data for T2 calculation. Noise in MRI has a non-vanishing mean, so that a non-zero signal is present at long TEs. Fitting to an exponential function results in systematic overestimation in T2 (up to 420% for low T2 and SNR). Two new methods for T2 calculation are proposed, which are very accurate and have a precision compatible with the maximal theoretical precision given by the Crámer-Rao lower bound. Impact of the fit on in vivo images has been analyzed.

2559. Resolving Multiple T2 Compartments in Cartilage with MRI David A. Reiter1, Ping-Chang Lin1, Kenneth W. Fishbein1, Richard G. Spencer1 1National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA

Monoexponential fitting of T2 relaxation imaging data has been used extensively to characterize properties of cartilage based on its sensitivity to macromolecular concentration and structure. Due to the macromolecular composition of cartilage which consists of water compartments of differing fractions and mobility, cartilage T2 relaxation is more appropriately described by a multiexponential function. We performed simulations to demonstrate the optimal imaging parameters for accurately and reliably resolving two component T2 relaxation of cartilage. This analysis was applied to intact and enzymatically degraded cartilage in order to demonstrate the diagnostic potential of this analysis.

2560. Dedicated Two-Channel Phased Array Receiver Coils for HR-MRI of the Rat Knee Cartilages at 7T Adrian Rengle1, Radu Bolbos1, 2, Jean-Christophe Goebel3, Mircea Armenean1, Astrid Pinzano-Watrin3, Hervé Saint-Jalmes4, 5, Pierre Gillet3, Olivier Beuf1 1INSA-Lyon, Université Lyon 1, Villeurbanne, France; 2University of California San Francisco, San Francisco, California , USA; 3Université Nancy I, Vandoeuvre, France; 4Faculté de Médecine, Université Rennes 1 , Rennes, France; 5Centre Eugène Marquis, Rennes, France

The goal of this work was to develop a dedicated two-channel array coil operating at 300 MHz (7T) for high-resolution MR imaging (HR-MRI) of the rat knee cartilage. A dedicated two-channel array coil with two square elements encompassing knee joint was designed and built. The average gain in Signal-to-Noise Ratio (SNR) compared to a 15 mm reference single loop coil was 2.2. This SNR gain was used to improve spatial resolution of 3D acquisition by decreasing the voxel size from 59x59x156µm3 to 51x51x94µm3 without time penalty. This two-channel array coil is a key element to perform HR-MRI and extract cartilage morphological parameters such as thickness and volume. Finally, a set of two array coils was used to perform the acquisition of both knee joints of a rat at the same time without SNR or resolution degradation compared to single knee joint acquisition. <

2561. Magnetization Transfer of Cartilage and Cartilage Repair Tissue at Ultra-High Fields Using SSFP Oliver Bieri1, Goetz H. Welsch2, Tallal Charles Mamisch3, Oliver Kraff4, Mark Edward Ladd4, Klaus Scheffler1, Siegried Trattnig2 1University of Basel, Basel, Switzerland; 2Medical University of Vienna, Austria; 3University Hospital, Bern, Switzerland; 4University Duisburg-Essen, Germany

Assessment of zonal differences in cartilage and its ultra-structure may benefit from improved image quality, contrast, and resolution at ultra-high fields. Here, magnetization transfer (MT) is evaluated for the assessment of cartilage repair. The feasibility of high resolution MT at 7T is demonstrated using MT sensitized steady-state free precession (MT-SSFP). Evaluation of MT for normal and for cartilage repair tissue reveals significant differences between healthy and affected articular cartilage. It is demonstrated that MT SSFP can successfully be used for the assessment of cartilage repair and areas of intact hyaline cartilage at 7T.

2562. 3D Distribution of T1ρ Relaxation Times in the Human Knee Joint Walter Robert Thurmond Witschey II1, Arijitt Borthakur1, Matthew Fenty1, J. Bruce Kneeland2, Matthew A. Sochor, Ravinder Reddy 1University of Pennsylvania, Philadelphia, USA; 2Pennsylvania Hospital, Philadelphia, USA

A biomarker for cartilage degeneration T1rho varies in the knee articular cartilage by location (patellar, femoral or tibial cartilage) and by proteoglycan and collage substructure (superficial, middle, and deep zones) using a fully 3D T1rho acquisition technique for axial and coronal slices. Elevated T1rho is shown in a single asymptomatic subject corresponding with focal cartilage loss and bony cyst development.

Poster Sessions

421

2563. 3D-FSE-Cube for Rapid Assessment of Cartilage Morphology in the Knee Christina A. Chen1, Richard Kijowski2, Brian A. Hargreaves1, Scott B. Reeder2, Reed F. Busse3, Anja C. S. Brau4, Philip J. Beatty4, Garry E. Gold1 1Stanford University, Stanford, California , USA; 2University of Wisconsin-Madison, Madison, Wisconsin, USA; 3GE Healthcare, Madison, Wisconsin, USA; 4GE Healthcare, Menlo Park, California , USA

The contrast provided by fast spin-echo (FSE) has made it the standard in assessing ligaments and menisci. However, two-dimensional FSE is limited by its incapability to measure cartilage volume. In healthy knees at 3.0T, we compared 3D-FSE-Cube to three-dimensional spoiled gradient-echo (SPGR) with IDEAL (Iterative Decomposition of water and fat with Echo Asymmetry and Least squares estimation). 3D-FSE-Cube yields equivalent cartilge volumes, higher fluid SNR, and better visualization of ligaments and menisci in a faster scan time than IDEAL-SPGR.

2564. Regional Difference of Diverse Zones in Human Menisci Investigated by Quantitative T2 Measurements Ping -Huei Tsai1, Teng-Yi Huang2, Hsiao-Wen Chung1, Guo-Shu Huang3 1National Taiwan University, Taipei, Taiwan; 2National Taiwan University of Science and Technology, Taipei, Taiwan; 3Tri-Service General Hospital and National Defense Medical Center, Taipei, Taiwan

The purpose of this study is to determine the T2 distributions within different zones of the menisci. Six normal subjects were enrolled in this preliminary study. All of them were imaging in supine position in a 3.0T MR system (achieva, Philips Medical System). Three regions of interest (ROIs) were manually defined including red zone , white zone with radial collagen fibers, and white zone with circular collagen fibers. Differences between any two groups were statistically significant (P < 0.0001). We conclude that quantitative T2 measurements help recognizing the functions of the menisci, with potential in clarifying the relationships among menisci, hyaline cartilage, and osteoarthritis.

Muscle Hall D Thursday 13:30-15:30

2565. Localized 31P Saturation Transfer Reveals Differences in Gastrocnemius and Soleus Rates of ATP Synthesis In-Vivo Douglas E. Befroy1, Kitt Falk Petersen1, Gerald I. Shulman1, 2, Douglas L. Rothman1 1Yale University School of Medicine, New Haven, Connecticut, USA; 2Howard Hughes Medical Institute, New Haven, Connecticut, USA

Distinct muscle groups exhibit differences in function and metabolic activity and also differ in their response to the effects of aging and potentially disease. Due to signal/noise limitations, most MR studies of metabolic reaction rates in-vivo tend to examine regions comprising multiple muscle types. We demonstrate that muscle-specific rates of ATP synthesis can be measured at 4T using adiabatic ISIS-localized 31P saturation-transfer MRS, and that there are significant differences in the basal rates of ATP synthesis between the soleus and gastrocnemius muscle groups in healthy subjects.

2566. Comparative Analysis of Calf Muscle Metabolism in Children and Adults: A 31P MRS Study Stefania Linsalata1, Amelia Mauro1, Roberta Battini1, Otello Presciutti2, Giovanni Cioni1, 3, Michela Tosetti1 1Stella Maris Scientific Institute, Pisa, Italy; 2University General Hospital, Perugia, Italy; 3University of Pisa, Pisa, Italy

We compared 31P MRS data obtained in the calf muscle of 4 children and 8 adults at rest, at the end of a short-term incremental exercise and during recovery. Our results in children show a significant reduction of the PCr consumption at the end of the exercise combined with a significant higher pH, possible expression of the great resistance to fatigue in children. Moreover a slightly reduction of both the time constant τ and the initial rate V of the PCr mono-exponential recovery confirms the hypothesis of a greater oxidative activity in children.

2567. In-Magnet Bicycling Exercise: A Novel 31P MRS Window on the Energetics of Human Locomotion Jeroen A.L. Jeneson1, Joep P.J. Schmitz1, Klaas Nicolay1 1Eindhoven University of Technology, Eindhoven, Netherlands

We have developed and implemented hardware on a clinical 1.5T MR scanner for innovative in-magnet bicycling exercise testing of human subjects. Three features of the first study reported here are of particular interest to (clinical) investigation of human exercise performance. Firstly, ATP metabolism in quadriceps muscle was studied over a 100-fold dynamic range with little intramuscular acidification. Secondly, the cardiovascular and pulmonary systems were significantly challenged during the exercise, with heart rates going up as high as 150 bpm. Finally, it provides a 31P MRS window on glycogen metabolism through the dynamics of hexose monophosphate resonances during exercise and recovery.

2568. Quantification of Fatty Septa in Skeletal Muscle of the Lower Leg by T1-Weighted MRI and Correlation to Anthropometric and Metabolic Data Jürgen Machann1, Michael Bottcher1, Fabian Springer1, Norbert Stefan2, Hans-Ulrich Haring2, Claus D. Claussen3, Andreas Fritsche2, Fritz Schick1 1Section on Experimental Radiology, Tübingen, Germany; 2Department of Endocrinology, Metabolism, Clinical Chemistry, Nephrology and Angiology, Tübingen, Germany; 3Department of Diagnostic Radiology, Tübingen, Germany

Intramyocellular lipids (IMCL) are involved in the pathogenesis of insulin resistance. Up to now, there is no information, whether also intermuscular fat (IMF), i.e. the fat around the muscle fiber bundles, might be of importance. Aim of the study was the quantification of IMF, subcutaneous fat (SCAT) and muscle mass by T1-weighted MRI in volunteers at increased risk for type 2 diabetes and to correlate the results with anthropometric and metabolic data. In 249 subjects it could be shown that males have higher IMF but lower SCAT compared to females and that IMF is negatively correlated with insulin sensitivity.

Poster Sessions

422

2569. Non-Negative Least Squares (NNLS) and Gated CSI Analyses of Phosphocreatine Recovery Kinetics in Human Skeletal Muscle Sean C. Forbes1, Anthony T. Paganini1, Jill M. Slade1, Theodore F. Towse1, Ronald A. Meyer1 1Michigan State University, East Lansing, USA

Phosphocreatine (PCr) recovery in human triceps surae muscle after low intensity exercise is mono-exponential, with the same recovery time constant in soleus, lateral, and medial gastrocnemius. In contrast, after intense exercise an additional, fast component of PCr recovery occurs which can be attributed to anaerobic glycogenolysis. Thus, contrary to previous studies, PCr recovery after intense exercise is not entirely dependent on oxidative metabolism.

2570. Identification of Distinct Patterns of Fat Metabolism in Skeletal Muscle of Male and Female Human Subjects Using Localized 2-Dimensional Correlated Spectroscopy Nicholas Said1, Kartik Narasimhan1, Cyrus Papan2, Richard G. Spencer3, Raymond R. Raylman1, Michael Albert Thomas4, Vazhaikkurichi M. Rajendran1, Stephen E. Alway1, S. Sendhil Velan1 1West Virginia University, Morgantown, USA; 2Institute of Bioengineering and Nanotechnology, Singapore; 3NIH/National Institute on Aging, Baltimore, USA; 4University of California, Los Angeles, Los Angeles, USA

Fatty acid metabolism plays a central role in the development of disorders of glucose metabolism, such as insulin resistance and diabetes, leading to significant interest in the detection of intramyocellular (IMCL) and extramyocellular (EMCL) pools in skeletal muscle. In this study we have established gender differences skeletal muscle lipids in a group of male and female human subjects, consistent with the notion that endocrine status plays a critical role in fat metabolism. The influence of harmonal factors was further underscored by observed changes during menstrual cycle.

2571. Rapid 13C Tip Angle / Coil Loading Calibration for in Vivo Natural Abundance 13C Studies in Humans Peter Edward Thelwall1 1Newcastle University, Newcastle upon Tyne, UK

Surface coils are frequently employed for quantitative human in vivo 13C spectroscopy studies. Differences in volunteer morphology, such as subcutaneous fat layer thickness, can result in different coil loading between volunteers. Thus non-optimal tip angles may result in some scans, with power requirement differences of >40% observed for our subjects.Tip angle calibration is hindered by low natural abundance 13C signal, so we have employed a protocol for rapid calibration of 13C coil power requirements that employs a external marker with a short-T1 13C resonance. Optimal data acquisition aided accurate estimation of muscle glycogen content by natural abundance 13C spectroscopy.

2572. Acute Effects of Rimonabant, a CB1 Receptor Antagonist, on IMCL and Plasma Parameters in Fed Wistar Rats – a 1H-MRS Study Claudia Neumann-Haefelin1, Johanna Kuhlmann1, Hans-Paul Juretschke1, Andreas W. Herling1 1Sanofi-Aventis, Frankfurt, Germany

Physiological and pharmacological studies for monitoring energy homeostasis focus predominantly on food intake, body weight and body composition, because these parameters are easily measurable in biomedical research. In acute preclinical studies cannabinoid CB1 receptor antagonists demonstrated an important reduction of food consumption and body weight. Until now rimonabant is the best characterized CB1 receptor antagonist and has been unequivocally proven to be pharmacological active in humans to reduce body weight and to improve metabolic parameters. The present study focus on the investigation of the acute pharmacological activity of rimonabant on metabolic plasma parameters and IMCL in fed Wistar rats.

2573. Effect of High and Low Glycemic Index Recovery Diets on Skeletal Muscle Glycogen and Lipid Storage and Utilisation Peter Edward Thelwall1, Emma Stevenson2, Kevin Thomas2, Michael Trenell1 1Newcastle University, Newcastle upon Tyne, UK; 2Northumbria University, Newcastle upon Tyne, UK

High levels of carbohydrate intake have been shown to improve glycogen repletion after exercise. We tested whether the glycemic index of carbohydrate consumed post-exercise influences the storage and utilisation of skeletal muscle glycogen and/or lipid during subsequent exercise. Endurance-trained cyclists performed two 90 minute cycles at 70% VO2 peak, separated by a 24 hour recovery period. Between exercise the subjects ate either low or high glycemic index diets. Muscle glycogen and intracellular triglyceride content was measured with 13C and 1H MR spectroscopy. No significant differences in glycogen or triglyceride storage or utilisation were observed between the two diet groups.

2574. Measurements of Taurine Distribution in Human Calf Muscle by 1H 2D-CSI at 7 Tesla Jimin Ren1, 2, Ivan Dimitrov1, 3, A. Dean Sherry1, 4, Craig Malloy1, 5 1University of Texas Southwestern Medical Center, Dallas, USA; 2University of Texas Southwestern Medical Cente, Dallas, USA; 3Philips Medical Systems, Cleveland, USA; 4University of Texas at Dallas, Richardson, USA; 5VA North Texas Health Care System, Dallas, USA

Taurine, the most abundant free amino acid in most mammalian tissues, plays a role in numerous physiological processes. A taurine deficiency in mice is associated with loss of skeletal muscle function and total exercise capacity. We examined taurine distribution in human calf muscle by using 1H 2D-CSI at 7T. The results show heterogeneous distribution of taurine in human calf muscle, with high level of taurine (~15-25 mM) found in soleus and gastrocnemius, but below detection limits in flexor hallicus and tibialis posterior, in contrast to the levels of creatine and trimethylamino resonances in these same muscles.

2575. Issues with Creatine/Phosphocreatine Quantification: Lipids Contamination and Water-Suppression Jimin Ren1, 2, Ivan Dimitrov1, 2, James Murdoch2, A. Dean Sherry1, 3, Craig Malloy1, 4 1University of Texas Southwestern Medical Center, Dallas, USA; 2Philips Medical Systems, Cleveland, USA; 3University of Texas at Dallas, Richardson, USA; 4VA North Texas Health Care System, Dallas, USA

Creatine/phosphocreatine (Cr/PCr) quantification by 1H MRS is of particular interest due to the importance of Cr/PCr in energy metabolism, and the reference role of CH3-Cr/PCr resonance at 3.05ppm in standardizing other metabolites. As shown in this study, however, the presence of large quantity of lipids in skeletal muscle may cause problems on CH3-Cr/PCr quantification, due to spectral overlapping between lipid and CH3-Cr/PCr. Furthermore, the lack of spectral resolution between lipids and CH3-Cr/PCr may have caused confusion when water-suppression is applied, since it is the lipid signal at 3ppm, rather than that of CH3-Cr/PCr, attenuates upon water suppression, as we demonstrated.

Poster Sessions

423

2576. High Resolution ASL and BOLD Imaging in Skeletal Muscle Using Spiral Sequences Hao Tan1, Justin Anderson1, Hanna Woldeyesus1, Christopher M. Kramer1, Craig H. Meyer1 1University of Virginia, Charlottesville, Virginia , USA

Interest has recently renewed in functional magnetic resonance imaging (fMRI) in skeletal muscle. Similarly to fMRI in brain imaging, the blood oxygenation level-dependent (BOLD) effect has been used to study peripheral artery disease (PAD). In this study, we developed a new spiral sequence with four gradient echoes to estimate T2* maps. This sequence is combined with the Flow-Sensitive Alternating Inversion Recovery (FAIR) pulsed arterial spin labeling (ASL) sequence to measure perfusion and T2* near simultaneously. The combined ASL and BOLD measurements before and after exercise show substantial promise in the evaluation of peripheral arterial disease.

2577. Investigations of Metabolic Differences Due to Differences in the Muscle Fiber Distribution by Using 31P-MRS at 3.0 T Reinhard Rzanny1, Norman Stutzig2, Alexander Gussew1, Werner Alois Kaiser, Hans_Alexander Thorhauer2, Jürgen Reinhard Reichenbach1 1Institute for Diagnostical and Interventional Radiology,University Hospital Jena, Jena, Germany; 2Friedrich-Schiller-University Jena, Jena, Germany

31P-MRS at 3.0T was performed in the M. gastrocnemius of 6 volunteers with different sportive activities. Spectra were acquired before and during an exhaustive dynamic exercise. Different pH changes in different fiber types during the exercise cause a split of the Pi signal into 2 or 3 components whose intensity ratio can be used to estimate the fiber distribution in the muscle. In this study the PCr/ATP ratios during rest were compared with the intensity ratio of the Pi components after split with reference to its prediction of the expected muscle fiber distribution in athletes corre-sponding to their sportive activity.

2578. Effect of Oral Creatine on Muscle Metabolism of Duchenne Muscular Dystrophy (DMD) by Phosphorus MRS Uma Sharma1, B Banerjee1, K Balasubramanian1, Veena Kalra1, N R. Jagannathan1 1All India Institute of Medical Sciences, New Delhi, India

Muscle energetics in Duchenne muscular dystrophy (DMD) patients was compared to controls and effect of oral creatine supplementation versus placebo was evaluated using phosphorus MRS and correlated with muscle strength and functional level. Phosphocreatine (PCr)/inorganic phosphate (Pi) and PCr/ â adenosine-tri-phosphate ratio were significantly lower in DMD compared to controls. A significant increase in creatine stores, marginal increase in manual muscle testing scores versus decrease in the placebo group suggested improvement in muscle strength on creatine supplementation. Creatine was found to be well tolerated and safe and a greater proportion of parents reported subjective improvement versus worsening on placebo.

2579. Reliability of an Incremental Wrist Extension Exercise Protocol Using 31P-MRS for Measuring Metabolic and Acid-Base Changes in the ECRB Muscle Graydon Raymer1, Howard Green2, Greg Marsh3, Terry Thompson4 1Nipissing University, North Bay, Canada; 2The University of Waterloo, Waterloo, Canada; 3The University of Western Ontario, London, Canada; 4The Lawson Health Research Institute, London, Canada

The objective of this study was to assess the reliability of an incremental wrist extension exercise protocol using 31P-MRS for measuring the metabolic and acid-base response in the extensor carpi radialis brevis (ECRB) muscle. Female participants performed two identical wrist extension protocols. Peak power output, [ATP], [PCr], [Pi], and pHi were not different between trials. The coefficient of variation for the onset of a rapid decrease in pHi was 4.3 % and for the onset of a rapid increase in [Pi]/[PCr] was 6.3%. Therefore, an incremental wrist extension exercise protocol provides a reliable test of ECRB metabolic and acid-base status.

2580. The Use of 31P MRS and Near-Infrared Spectroscopy (NIRS) to Assess the Kinetics of Children and Adults at the Onset of Moderate Intensity Exercise Jon Fulford1, Deborah Welford2, Joanne Welsman3, Neil Armstrong3, Alan Barker3 1Peninsula Medical School, Exeter, UK; 2University of Wales Institute Cardiff, Cardiff, UK; 3University of Exeter, Exeter, UK

31P and near-infrared spectroscopy were used to assess whether any changes can be detected between individuals due to age and/or sex at the onset of moderate intensity exercise. The kinetics of muscle PCr were found to be independent of age and sex. However, there is the suggestion of age-related variation of deoxy-haemoglobin dynamics, which may reflect an underlying imbalance between muscle O2 delivery and utilisation in children.

2581. Detection of Skeletal Muscle Mitochondrial Dysfunction in Pulmonary Arterial Hypertension Mirko Hrovat1, Chris Farrar2, James J. Tolle2, Patrick Gordan2, Gregory D. Lewis2, Paul Pappagianopoulos2, David Systrom2 1Mirtech, Inc., Brockton, Massachusetts, USA; 2Massachusetts General Hospital, Boston, Massachusetts, USA

This laboratory has recently described blunted systemic oxygen extraction at maximum exercise in pulmonary arterial hypertension (PAH). This was further investigated with 31P MRS. Results suggest that delayed limb skeletal muscle PCr recovery following submaximal exercise with normal arterial O2 content suggests an intrinsic abnormality of mitochondrial ATP synthesis and that PAH is more of a systemic disease than previously recognized.

2582. Potential of 23Na-MRI in Muscular Sodium Channel Diseases Armin Michael Nagel1, Marc-André Weber1, Frank Lehmann-Horn2, Karin Jurkat-Rott2, Lothar Rudi Schad 1German Cancer Research Center, Heidelberg, Germany; 2University Ulm, Germany

The purpose of this study was to show the feasibility of 23Na-MRI for the examination of patients with paramyotonia congenita (PC) and testing for specific therapies. A density adapted 3D Radial sampling scheme was used to measure the sodium concentration in the lower leg muscles of a patient with confirmed PC, a muscular sodium channelopathy, and of a healthy volunteer. After cooling one leg the sodium concentration in the patient’s cooled leg increased, whereas in the volunteer’s cooled leg no significant difference was observed. Furthermore a zinc medication was tested in the patient.

Poster Sessions

424

2583. Chromium Oxide Nanoparticle Distribution: An MRI Study in Rats Sanjay Annarao1, Deepak Gurbani2, K Jayalakshmi, Neeraj Sinha, Devendra Parmar2, Alok Dhawan2, Raja Roy1, C. L. Khetrapal1 1Centre of Biomedical Magnetic Resonance, Lucknow, India; 2Industrial Toxicology Research Centre, Lucknow, India

Distribution of Chromium oxide nanoparticles administered by intraperitoneal, intravenous, dermal, intramuscular and oral routes in rats was studied using Magnetic Resonance Imaging. The results indicate that Chromium oxide nanoparticles produce contrast in images of thigh and testicular regions only when chromium oxide nanoparticles were administered dermally and intramuscularly. This indicates efficient absorption of chromium oxide nanoparticle by skin followed by its uniform distribution in the thigh and testicular region.

2584. Muscle Metabolism and Acid-Base Status During Exercise in Work-Related Forearm Myalgia Measured with 31P-MRS Graydon Raymer1, Howard Green2, Don Ranney2, Greg Marsh3, 4, Terry Thompson, 34 1Nipissing University, North Bay, Canada; 2The University of Waterloo, Waterloo, Canada; 3The University of Western Ontario, London, Canada; 4The Lawson Health Research Institute, London, Canada

We studied the metabolic and acid-base status during exercise in the forearm of individuals with work-related myalgia (WRM) using 31P-MRS. We observed a lower pHi (P<0.05) and greater [Pi-]/[PCr] (P<0.05). The onset of a faster decrease in pHi and the onset of a faster increase in [Pi]/[PCr] occurred at a lower relative power output in WRM (P<0.05). Data collected during the recovery from exercise showed a slower rate of restoration for pHi (P<0.05). In conclusion, our results suggest a reduced contribution of oxidative phosphorylation WRM, possibly a result of reduced blood flow and perfusion.

2585. Inverse Correlation Between IMCL Content of the Human Calf Muscle and local Glycogen Synthesis Rate Marinette van der Graaf1, Cees J.J. Tack1, Jacco H. de Haan1, Dennis W.J. Klomp1, Arend Heerschap1 1Radboud University Nijmegen Medical Center, Nijmegen, Netherlands

IMCL content in the soleus and gastrocnemius muscle was determined by 1H MRSI in twenty subjects belonging to four subgroups: young lean, elderly lean, young obese and elderly obese. In addition, local glycogen synthesis rate was measured by 13C MRS during a euglycemic-hyperinsulinemic clamp with 13C-1-glucose infusion. IMCL contents were higher in elderly (soleus: P<0.0001 and gastrocnemius: P<0.01) and obese subjects (P<0.01 for both muscles), and glycogen synthesis rate decreased with obesity (P<0.01). The principal finding was an inverse correlation between the mean IMCL content of the calf muscles and the local glycogen synthesis rate within the same muscle compartment (rs=-0.50, P<0.05).

2586. 1H MRS as Evaluation Tool of the Effects of β-Alanine Supplementation on the Muscle Carnosine Content in Soleus and Gastrocnemius of 400m Sprinters Harmen Reyngoudt1, Mahir Sinan Özdemir2, Andries Pottier1, Katrien Koppo1, Roger C. Harris3, J A. Wise4, Eric Achten1, Wim Derave1 1Ghent University Hospital, Ghent, Belgium; 2Ghent University, Ghent, Belgium; 3University of Chichester, Chichester, UK; 4Natural Alternatives International, San Marcos, USA

Carnosine is a dipeptide that is present in brain and skeletal muscle of humans and various animals. It is reported to play a buffering role in the physiological pH range during skeletal muscle contractions. In this study the effects of beta-alanine supplementation were evaluated by H MRS in a double-blind study. Carnosine has two well-discernable resonances at 7 and 8 ppm. Absolute quantification was performed in soleus and gastrocnemius using an external reference. Carnosine concentrations increased by 47% and 37% in soleus and gastrocnemius, respectively, following supplementation with beta-alanine. There was no significant increase (8%) in soleus and a smaller increase (16%) in gastrocnemius in the placebogroup. These experiments show that 1H MRS can be used to quantify carnosine in a non-invasive way.

2587. Effect of PH on CEST in Muscle Elizabeth April Louie1, 2, Mark D. Does3, Daniel F. Gochberg2, Bruce M. Damon2 1Vanderbilt University Medical Center, Nashville, Tennessee, USA; 2Vanderbilt University , Nashville, Tennessee, USA; 3Vanderbilt University, Nashville, Tennessee, USA

Proton chemical exchange rates between molecules and water is pH sensitive. Intracellular pH of muscle decreases during intense exercise. A detection method to discern active muscle regions would be beneficial for studying muscle metabolism, diseases, and aging. Excised frog gastrocnemius muscle was used as a model for exercised muscle to determine the sensitivity of CEST for a pH change of 0.5. Preliminary results show a 1% difference in the magnetization transfer asymmetry plot of the amide resonance between the acidic and control muscles. Future studies include stimulating muscle to test whether CEST can detect glycogen concentration changes in muscle.

2588. Implementation and Validation of Localized Constant-Time PRESS Sequence for Investigation of Skeletal Muscle Metabolism S. Sendhil Velan1, Kartik Narasimhan1, Richard G. Spencer2, Raymond R. Raylman1, Stephen E. Alway1 1West Virginia University, Morgantown, USA; 2NIH/National Institute on Aging, Baltimore, USA

We have implemented a novel single-voxel based two-dimensional constant-time (CT) spectroscopic method on a clinical 3T MRI/MRS scanner. We have validated the technique with theoretical simulations and experimental results to achieve homonuclear decoupling and also to maximize the signal to noise ratio with optimal constant time. Finally we demonstrate the separation of olefinic protons within IMCL and EMCL and other resonances from these two lipid pools.

Poster Sessions

425

2589. Muscle T2 Measurement and Gadolinium Uptake in Duchenne Muscular Dystrophy: Effect of Exercise in DMD Boys and Comparison with Healthy Controls Kieren Grant Hollingsworth1, Penny Garrood1, Benjamin S. Aribisala1, Daniel Birchall2, Michelle Eagle1, Kate Bushby1, Volker Straub1 1Newcastle University, Newcastle Upon Tyne, UK; 2Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle Upon Tyne, UK

The pelvic, thigh and calf muscles of 11 ambulant boys with DMD were assessed for T2 value and magnitude of gadolinium uptake before, and 4 days after, a challenging step test. 6 healthy adult volunteers acted as controls. For all muscles studied, T2 values and signal intensity increase with gadolinium were higher in the DMD children, reflecting inflammation and consequent increase in interstitial volume. The tibialis anterior muscles of both legs showed significantly greater enhancement 4 days post-exercise, and calf muscles showed a greater tendency to increased enhancement than thigh muscles. There were no significant changes in T2 value post-exercise.

2590. In Vivo Characterization of Skeletal Muscle Fiber Ellipticity with Diffusion-Weighted MRI Dimitrios C. Karampinos1, 2, Kevin F. King2, Bradley P. Sutton1, John G. Georgiadis1 1University of Illinois at Urbana-Champaign, Urbana, Illinois, USA; 2General Electric Healthcare, Waukesha, Wisconsin, USA

Diffusion Tensor Imaging of the skeletal muscle has shown that the secondary eigenvalue is consistently higher than the tertiary eigenvalue. It is also well-known from histology that the cross-section of skeletal muscle fibers is elliptical. In the present study, we propose a model which is consistent with the muscle histo-architecture and apply it to interpret DTI measurements obtained on sections of a human calf muscle. We demonstrate how DTI measurements can be used to produce maps of the postulated myofiber ellipticity and propose a hypothesis on the connection of this asymmetry to mechanical behavior upon contraction.

2591. Deep Tissue Injury in Skeletal Muscle: Correlation Between Tissue Damage and Internal Strains as Studied by MR Tagging, T2-Weighted MRI and FE Modeling Anke Stekelenburg1, Karlien K. Ceelen1, Joost L.J Mulders1, Gustav J. Strijkers1, Cees W. Oomens1, Frank P. Baaijens1, Klaas Nicolay1 1Eindhoven University of Technology, Eindhoven, Netherlands

Pressure ulcers are localized areas of tissue necrosis caused by compression of soft tissues. The underlying mechanisms of deep pressure ulcers are poorly understood. In the present study the correlation between the location of tissue damage, measured by T2-weighted MRI, and the location of high strains, determined by MR tagging and FE modeling, was investigated. The MR tagging experiments were used to validate the FE model. It was demonstrated that the amount of damage increased with increasing shear strain. This demonstrates the importance of large deformations, besides ischemia, in the etiology of deep pressure ulcers.

2592. Velocity Encoded-Phase Contrast MRI Reveals in Vivo Tissue Dynamics of the Human Medial Gastrocnemius During Isometric Contraction Ryuta Kinugasa1, Dongsuk Shin2, John A. Hodgson2, Reggie V. Edgerton2, Shantanu Sinha1 1University of California San Diego, San Diego, California , USA; 2University of California Los Angels, Los Angels, California , USA

Using Velocity-encoded phase-contrast MR imaging, the velocity and displacement along the length of both the deep and superficial aponeurosis of the medial gastrocnemius were determined during sub-maximal voluntary isometric contractions. Contrary to present belief in literature, instead of stretching homogenously along their lengths, the displacement of different regions of the two aponeuroses were heterogeneous during isometric contraction. Such detailed information is imperative for proper modeling of the human musculoskeletal system.

2593. Myofiber and Microvasculature Architecture of Human Calf Muscle Alteration in Passive Dorsiflexion Dimitrios C. Karampinos1, 2, Kevin F. King2, Danchin Chen1, Lucija Rakocevic1, John G. Georgiadis1 1University of Illinois at Urbana-Champaign, Urbana, Illinois, USA; 2General Electric Healthcare, Waukesha, Wisconsin, USA

We combine Diffusion-Weighted MRI techniques (IVIM and DTI) and employ a home-made MRI-compatible cradle for leg immobilization, to quantify in vivo changes in muscle fiber architecture and perfusion following passive dorsiflexion of the foot. The resulting stretching of the gastrocnemius muscle is associated with a significant decrease in local perfusion, and a modest decrease in pennation angle and T2, all consistent with measurements obtained with various imaging modalities.

2594. A Strain Analysis of the Lower Leg During Ankle Rotation Using HARP at 3 Tesla Michael A. Green1, Simon C. Gandevia1, Lynne E. Bilston1 1Prince of Wales Medical Research Institute, Sydney, Australia

A quantified strain analysis of muscle motion in the distal leg of healthy volunteers has been performed using the HARP imaging technique with a 3T full body scanner. Principal strain measurements have been achieved by examining tagged images of the muscles before and after rotation about the ankle for plantarflexion and dorsiflexion. Quantified results have shown large strains in the medial gastrocnemius and soleus. Principal strain directions have also been measured and may provide more information of intramuscular properties relating to muscle fascicle direction and pennation angle.

2595. Quantitative T2 Maps in Idiopathic Inflammatory Myopathy: Correction for Fatty Involution of Muscle Lawrence Yao1, Neville Gai2 1NIH, Bethesda, Maryland, USA; 2NIH, USA

Active muscle disease in patients with idiopathic inflammatory myopathy may be quantified with bulk T2 measurements. We illustrate an improved clinical T2 MR measurement that is corrected for muscle fat fraction. This method may be more valid in cases of advanced or chronic muscle damage.

Poster Sessions

426

2596. Monte Carlo Simulation of Muscle Diffusion: Effect of SNR Bruce M. Damon1, Zhaohua Ding1, Adam W. Anderson1 1Vanderbilt University, Nashville, Tennessee, USA

Diffusion-tensor MRI (DT-MRI) is a promising tool for structural characterization of muscle, including fiber tracking. Partial volume artifacts due to intramuscular fat deposition require the development of new tracking algorithms capable of distinguishing between muscle and fat diffusion properties on the basis of readily measurable MR parameters. The purpose of this study was to test the dependence of the muscle and fat DT on the signal-to-noise ratio (SNR), using Monte Carlo simulations. We found that muscle DT-MRI has high SNR requirements and that fractional anisotropy cannot distinguish between fat and muscle at typical SNR values.

2597. Ankle Orientation Alters Bulk Susceptibility and Residual Dipolar Couplings During Plantar Flexion and Dorsiflexion of Skeletal Muscle S. Sendhil Velan1, Nicholas Said1, Kartik Narasimhan1, Richard G. Spencer2, Raymond R. Raylman1, Vazhaikkurichi M. Rajendran1, Stephen E. Alway1 1West Virginia University, Morgantown, USA; 2NIH/National Institute on Aging, Baltimore, USA

Quantification of skeletal muscle MRS spectra is influenced by bulk magnetic susceptibility shifts resulting in variable separation between intramyocellular and extramyocellular lipid resonances in different muscle compartments. In addition certain metabolites exhibit residual dipolar couplings between nuclei altering the multiplicity and amplitudes. Both effects are dependent upon the ankle orientation which alters the muscle fibers with respect to the main magnetic field direction. In this work we have assessed the nature of the bulk susceptibility and residual dipolar interactions through the effect of geometric changes which can be accounted for in a reproducible manner, permitting improved quantification and reproducibility.

2598. Ultrashort-T2 and Magic-Angle Contrast: A Comparison Juergen Rahmer1, Peter Börnert1 1Philips Research Europe, Hamburg, Germany

Certain types of highly ordered tissues, such as tendons, ligaments, or peripheral nerves, show a variation in T2 relaxation time depending on the orientation with respect to the external field B0. The effect is caused by residual dipolar coupling that vanishes at an angle of 54.7 degrees, called the magic angle. Measuring an anatomy at different angles towards the external field allows identification and selective visualization of tissue components that are subject to dipolar effects. Furthermore, information about the microscopic fiber orientation can be obtained. While the arising contrast can be termed magic angle contrast, ultrashort TE (UTE) imaging enables the visualization of a general short-T2* contrast caused by dipolar and other decay mechanisms. In this work, both contrasts are acquired to characterize short-T2 components in tendons and bones of the hand, using 3D isotropic data measured at UTE and a later echo time at various orientations.

Renal Hall D Monday 14:00-16:00

2599. Magnetic Resonance Detection of Kidney Iron Deposition in Sickle Cell Disease: A Marker of Chronic Hemolysis Aaron Schein1, 2, Cathleen Enriquez2, Thomas D. Coates2, John Wood2 1Keck School of Medicine, Los Angeles, California , USA; 2Children's Hospital Los Angeles, Los Angeles, California , USA

T2* signal, which decreases near tissue iron deposits, serves as a surrogate for tissue iron in magnetic resonance images (MRI). We found that R2* (1000/T2*) signal increased linearly in the kidneys of sickle cell disease (SCD) patients with the hemolytic marker lactate dehydrogenase, demonstrating here that chronic hemolysis is coupled to renal hemosiderosis. Kidney iron load, unlike in the heart and liver, was not related to chronic blood transfusions. Though prospective studies are needed, renal R2* as a noninvasive biomarker of chronic hemolysis in SCD patients may correlate with other hemolytic sequelae such as pulmonary hypertension and systemic vasculopathies.

2600. Evaluation of Venous Extension in Renal Cell Carcinoma Using a 2D Fat-Saturated Steady State Free Precession Sequence David W. Stanley1, Christine U. Lee2, James F. Glockner2 1GE Healthcare, Rochester, Minnesota, USA; 2Mayo Clinic, Rochester, Minnesota, USA

Evaluation of abdominal-pelvic venous disease with MRI is widely accepted. Conventional contrast-enhanced 2D and 3D SPGR sequences are very accurate in detecting venous thrombus; however, given growing concerns regarding the use of gadolinium-based contrast media in patients with renal dysfunction, non-contrast techniques have become increasingly important. We investigated venous staging of 14 patients with renal cell carcinoma using an overlapping fat-saturated steady state free precession sequence, and compared the results with a more traditional contrast-enhanced 3D SPGR sequence.

2601. Quantification and Validation of Kidney Perfusion Imaging in the Cortex and Medulla with DCE-MRI Using a Blood Pool Contrast Agent in a Swine Model Lutz Lüdemann1, Benno Nafz1, Franz Elsner1, Michael Meißler1, Nicola Kaufels1, Christian Große-Siestrup1, Pontus Persson1, Matthias Gutberlet2, Philipp Lengsfeld3, Matthias Voth3 1Charité, Berlin, Germany; 2Universitätsklinik Leipzig, Leipzig, Germany; 3Bayer Schering Pharma AG, Berlin, Germany

The aim of this animal study was to show the feasibility of quantification of total as well as cortical and medullary renal perfusion with DCE-MRI using an approved blood pool agent. A total of 18 female pigs were investigated. A modified ultrasound transit time flow probe was used o measure absolute renal blood flow and compared with blood flow determined by DCE-MRI. The kidney blood flow measured by ultrasound highly correlated with the total kidney perfusion determined by DCE-MRI, P<0.001. Cortical and medullary flow were also highly correlated with the degree of flow reduction, P<0.001. The DCE-MRI technique presented allows absolute quantification of total kidney perfusion as well as separate determination of cortical and medullary flow.

Poster Sessions

427

2602. Improvement of Functional MRI Measurement with Automatic Movement Correction in Native and Transplanted Kidneys Baudouin Denis de Senneville1, Iosif Mendichovszky2, Sébastien Roujol1, 3, Isky Gordon2, Chrit Moonen1, Nicolas Grenier4 1CNRS, Bordeaux, France; 2UCL Institute of Child Health, London, UK; 3Ecole Nationale Supérieure d’Electronique, Informatique et Radiocommunications de Bordeaux, Bordeaux, France; 4Groupe Hospitalier Pellegrin, Bordeaux, France

Non-invasive and accurate measurement of renal perfusion and glomerular filtration rate (GFR) could have a major impact on understanding renal physiopathology and for serial monitoring of the course of many acute and chronic kidney diseases. Dynamic contrast-enhanced magnetic resonance imaging can now be used for the evaluation of these functional parameters. This study describes a suitable method for 2D correction of kidney motion during the passage of the bolus of contrast with subpixel accuracy. The Patlak-Rutland model was used to calculate GFR in the kidney cortex on a voxel-by-voxel basis.

2603. Influence of Oxygen and Carbogen Breathing on Renal Oxygenation Measured by BOLD- Imaging at 3.0 Tesla Andreas Boss1, Petros Martirosian, Margit Jehs, Cristina Rossi, Klaus Dietz, Claus D. Claussen, Fritz Schick 1University Hospital of Tübingen, Tübingen, Germany

The aim of the present study was to assess whether carbogen (95% O2, 5% CO2) or pure oxygen breathing can influence renal oxygenation. Changes in the renal tissue oxygenation were measured using blood oxygenation level dependent (BOLD) magnetic resonance imaging. It was demonstrated in this study, that renal tissue oxygenation may be influenced with carbogen or oxygen breathing. The changes can be assessed with T2*-weighted MRI at high field strength. The effects are in the expected range for the BOLD effect of 3-4% at 3.0 Tesla.

2604. Renal Blood Oxygen Level Dependent (BOLD) Magnetic Resonance Imaging in a Rodent Model of Hypertension Mediated End Organ Damage Stephen C. Lenhard1, Amy Grill1, karpagam Aravindhan1, Ross Bentley1, Kristeen Maniscalco1, Chris P. Doe1, Robert N. Willette1, Beat Michael Jucker1 1GlaxoSmithKline, King of Prussia, Pennsylvania, USA

Changes in the renal BOLD MRI signal can be interpreted as changes in tissue pO2 in hypoxic environments such as the renal medulla and possibly cortex. In this study, we have implemented BOLD MRI in the renin dTg (double transgenic overexpressing both human angiotensinogen and human renin) rat model of hypertension to characterize changes in renal tissue oxygenation during the progression of renal dysfunction. Additional relationships between medullary and cortical BOLD signal with urine microalbumin excretion was examined.

2605. Importance of T1-Correction in T1-Weighted MR Renal Perfusion Measurements Christian Kremser1, Mohamed Abd Ellah1, Leo Pallwein-Prettner1, Christian Wolf1, Ferdinand Frauscher1, Georg Bartsch1, Werner Jaschke1, Michael Schocke1 1Innsbruck Medical University, Innsbruck, Austria

To obtain reliable renal perfusion values from dynamic contrast enhanced MRI, signal calibration has to be performed to avoid errors due to non-linear signal behavior. It was the purpose of this study to demonstrate how the omission of signal calibration may influence the results and conclusions of clinical studies.

2606. 3D Respiratory Triggered T2-Weighted Imaging of the Kidneys with 3D-FSE-Cube Jonathan William Currie1, Reed F. Busse, Thomas Winter1, Anja C. Brau, Philip J. Beatty, Jean H. Brittain, Scott B. Reeder 1University of Wisconsin, Madison, Wisconsin, USA

T2 weighted FSE imaging of the kidneys, renal collecting system and ureters provides excellent contrast for evaluation of cystic renal neoplasms as well as other urological abnormalities, and is an important component of a complete evaluation of the kidneys. However, 2D methods are limited by partial volume averaging effects. MR evaluation of the kidneys would greatly benefit from 3-dimensional imaging and improved spatial resolution. 3D-FSE-Cube is a volumetric technique that provides high quality near isotropic resolution imaging of solid abdominal organs such as the kidneys. The purpose of this work is to demonstrate 3D FSE T2 weighted imaging of the kidneys using 3D-FSE-Cube.

2607. 23Na MRI of In Vivo Rat Kidneys at 3.0 T: Preliminary Experience Pottumarthi Vara Prasad1, Alexander Ivanishev2, Robert Greenman2, Lu Ping Li1, Ying Wu1, Joann Carbray1, Jeffrey Stainsby3, Andres Carrillo4, Robert E. Lenkinski2 1Evanston Northwestern Healthcare, Evanston, Illinois, USA; 2Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA; 3GE Healthcare, Toronto, Canada; 4GE Healthcare, Evanston, Illinois, USA

In vivo 23Na MRI has shown to be useful for functional evaluation of the kidneys. We present our preliminary experience in implementing 23Na MRI on a clinical whole body 3.0 T scanner equipped with multinuclear capability. Using custom developed quadrature transmit/receive volume coil we have demonstrated feasibility of obtaining 23Na MRI of in vivo rat kidneys. In combination with standard proton extremity coil, position matched high resolution proton images were obtained with relative ease. Data demonstrating acute spatio-temporal changes in sodium concentration following administration of furosemide are also presented.

2608. Optimization of the Determination of the Corticomedullary Sodium Gradient from Na-23 Images of the Human Kidney Robert E. Lenkinski1, Yael Rosen1, Ananth Madhuranthakam2, Alex Ivanishev1 1Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA; 2GE Healthcare, Boston, Massachusetts, USA

We have evaluated a combination of an acquisition weighted pulse sequence and Fermi filtering to determine the sodium concentration gradient in a phantom. We found that it was possible to improve the SNR by a factor of 1.7 while preserving the ability to determine the sodium concentration gradient. We also applied this approach to data obtained on a human kidney and found similar results.

Poster Sessions

428

2609. The Influence of Tissue Composition on Signal to Noise Ratio of MR Measurements Zhengyu Yang1, Tuhin Kumar Sinha1, John C. Gore1 1vanderbilt institute of imaging science, nashville, Tennessee, USA

All MRI image contain some spatial variance of signal because of the presence of additive random noise. However, at high spatial resolution some of this variance may reflect not only thermal noise (temporal variance, which averages incoherently as more images are acquired) but also microscopic inhomogeneities in tissue composition (spatial variance),which comes from variations in tissue composition. We have developed methods to quantify and examine the nature of these spatial variances in MR images. The ultimate goal of this research is to determine how these systematic variances correlate with the underlying macro-molecular composition of tissues.

Liver Hall D Tuesday 13:30-15:30

2610. Effect of Pioglitazone Treatment on Liver Fat and Visceral Fat in Patients with Congenital Adrenal Hyperplasia Marinette van der Graaf1, Jeanne M. Kroese1, Ivonne van Loosbroek1, Cees J.J. Tack1, Arend Heerschap1 1Radboud University Nijmegen Medical Center, Nijmegen, Netherlands

Patients with Congenital Adrenal Hyperplasia (CAH) receive a lifelong (over)supplementation with glucocorticoids which treatment induces insulin resistance. Pioglitazone is a medication that improves insulin sensitivity, probably by shifting fat from the liver/intra-abdominal compartment to the subcutaneous compartment. The effect of pioglitazone treatment was evaluated in CAH patients in a double blind, randomized, placebo-controlled cross-over study with measurement of hepatic lipid content and abdominal fat distribution by MRS and MRI, respectively. The results showed no significant effect of pioglitazone treatment on hepatic lipid content and abdominal fat distribution in this relatively healthy, lean and young patient group.

2611. Application of Liver MR Elastography in Clinical Practice Sudhakar Kundapur Venkatesh1, Meng Yin1, Jayant A. Talwalkar1, Richard L. Ehman1 1Mayo Clinic, Rochester, Minnesota, USA

MR Elastography has been validated as a diagnostic tool for non-invasive assessment of liver fibrosis in several independent studies. Based on these findings, the technique has been adopted as a routine clinical test at our institution. This study reports results from our first 281 liver MRE examinations, performed for clinical indications. The most common indication was to follow patients with known hepatic fibrosis. The use of MRE affected subsequent clinical management in several ways, most commonly by influencing the decision to biopsy. Many patients who have been evaluated with MRE have been able to avoid invasive biopsy.

2612. Acceleration of MR Elastography with Parallel MR Imaging David W. Stanley1, Sudhakar K. Venkatesh2, Meng Yin2, Ken Hwang3, Richard L. Ehman2 1GE Healthcare, Rochester, Minnesota, USA; 2Mayo Clinic, Rochester, Minnesota, USA; 3GE Healthcare, Houston, Texas, USA

MR Elastography (MRE) is increasingly being used to measure tissue stiffness in different areas of the body, especially in the liver, for the evaluation of fibrosis and end-stage cirrhosis. . Parallel imaging techniques are widely used to reduce scan time and we sought to apply them to allow an entire data set for MRE to be acquired in a single breath-hold. The purpose of this study was to evaluate the performance of a parallel MRE acquisition technique and compare it to our optimized conventional non-accelerated MRE technique.

2613. Non-Invasive Diagnosis of Liver Fibrosis: Conventional MR Imaging Findings Versus MR Elastography Sudhakar Kundapur Venkatesh1, 2, Naoki Takahashi1, James F. Glockner1, Meng Yin1, Jayant A. Talwalkar1, Roger C. Grimm1, Armando Manduca1, Richard L. Ehman1 1Mayo Clinic, Rochester, Minnesota, USA; 2National University of Singapore, Singapore, Singapore

An accurate, reproducible and noninvasive method for determining hepatic fibrosis is needed, as liver biopsy is invasive with risk of complications and sampling errors. Some findings in conventional MRI have been found useful for detection of cirrhosis. Recently MR Elastography has been shown to be an accurate method for detection of fibrosis. We undertook a study to compare conventional MRI with MRE for detection of liver fibrosis. While the presence of gross morphologic changes allows diagnosis of advanced hepatic fibrosis with conventional MRI, we found that MRE was more sensitive and capable of detecting fibrosis at a much earlier stage.

2614. Cross-Validation of the Magnetic Resonance Elastography Technique to Measure the Liver Stiffness sabine fanny Bensamoun1, Lu Wang, Ludovic Robert, Fabrice Charleux, Jean-Paul Latrive, Marie-Christine Ho Ba Tho 1Université de Technologie de Compiègne, compiègne, France

The purpose of this study is to cross-validate the MRE technique with a routinely used clinical device. Five healthy volunteers underwent firstly a MRE scan and secondly a Fibroscan exam. The shear moduli obtained with both techniques are in the same range. The originality of this study was firstly to attest the feasibility of the MRE to measure liver stiffness and secondly to show why MRE should be investigated beyond the Fibroscan the MRE technique provided elasticity of the entire liver, meanwhile the Fibroscan provided values of elasticity locally.

2615. Improved Method for Liver Iron Imaging Using MR Susceptibility Weighted Imaging (SWI) Yingjian Yu1, Anil Shetty2, Jeffrey Kim3, Tushar Desai2, E Mark Haacke1, 4 1Wayne State University, Detroit, Michigan, USA; 2William Beaumont Hospital, Royal Oak, Michigan, USA; 3School of Medicine Wayne State University, Detroit, Michigan, USA; 4MRI Institute of Biomedical Research, Detroit, Michigan, USA

Susceptibility Weighted Imaging (SWI) was used to test the efficacy for better characterization of iron overloading. This study shows that the SWI filtered phase images may provide better information than the conventional T2 or T2* approach in heavily iron overloaded patients.

Poster Sessions

429

2616. Perfusion Quantification in Hepatocellular Carcinoma Using Dynamic Contrast-Enhanced MRI R. Scott Johnson1, Henry Rusinek1, Artem Mikheev1, Louisa Bokacheva1, Herman Yee1, Cristina Hajdu1, Bachir Taouli1 1NYU Medical Center, New York, New York, USA

We used dynamic contrast-enhanced MRI in 24 patients including 16 with hepatocellular carcinoma (HCC) using a 3D GRE sequence with a temporal resolution of 3 to 5 sec. Perfusion metrics of HCC were quantified using time concentration curves and a dual input single compartmental model, showing significantly elevated arterial flow and decreased portal venous flow in HCC compared to cirrhotic liver. We conclude that DCE-MRI can potentially be used as a non-invasive marker of HCC angiogenesis.

2617. Serial Apparent Diffusion Coefficient Measurements in Hepatocellular Carcinoma Before and After Transarterial Chemoembolization Lorenzo Mannelli1, Sooah Kim1, Cristina Hajdu1, Mariela Losada1, Timothy Clark1, Bachir Taouli1 1NYU Medical Center, New York, New York, USA

We demonstrated significant increase in tumor apparent diffusion coefficient (ADC) in 47 hepatocellular carcinomas (HCCs) treated with transarterial chemoembolization (TACE) and a significant correlation between lesion ADC and % of necrosis measured with subtracted post-contrast images and % of necrosis at pathology. We conclude that ADC could be used as a marker of HCC ischemic necrosis after TACE.

2618. Assessment of Ex-Vivo Livers for Steatosis Using MRI: Feasibility in Cadaveric Livers Catherine Diane Gard1, Thomas F. Warner1, Luis A. Fernandez, Alexandru I. Musat1, Adnan Said1, Phil Robson2, Huanzhou Yu3, Jean H. Brittain4, Scott B. Reeder1 1University of Wisconsin-Madison, Madison, Wisconsin, USA; 2Beth Israel-Deaconess Medical Center, Boston, Massachusetts, USA; 3GE Healthcare, Menlo Park, California , USA; 4GE Healthcare, Madison, Wisconsin, USA

Current methods of evaluation of livers for transplant rely on biopsy, which is subject to high sampling variability, tissue damage and infection. Here, we apply MRI to assess the quality of human livers harvested for liver transplantation for steatosis using IDEAL water-fat separation and MR spectroscopy to quantify hepatic fat content, in comparison to lipid extraction and histological grading. We found good correlation between IDEAL, MRS and PRESS with lipid extraction and histological grading. MRI may be a feasible means for assessment of steatosis in human livers harvested for transplantation.

2619. T1 and T2 Relaxation in Fat Quantification Using FSE Sequences Takeshi Yokoo1, Mark Bydder1, Damien L. Stella2, Nick C. Pinto1, Michael S. Middleton1, Claude Sirlin1 1University of California, San Diego, California , USA; 2Royal Melbourne Hospital, Melbourne, Australia

Imaging using FSE sequences with and without fat suppression provides a way to estimate fat in the liver, avoiding the T2* and B0 inhomogeneity problems associated with GRE. However T1 and T2 relaxation may still affect the measured fat fraction.

2620. Evaluation of Fat in the Liver; Comparative Study with MR Spectroscopy, MEDAL, and CT Takayuki Masui1, Motoyuki Katayama1, Haruyuki Fukuchi2, Kimihiko Sato1, Hidekazu Seo1, Hiroki Ikuma1, Megumi Ishii1, Kenji Asano2, Atsushi Nozaki2, Hasnine Akter Haque2, Shun Imamura1, Masayoshi Sugimura1 1Seirei Hamamatsu General Hospital, Hamamatsu, Japan; 2GEYMS, Hino, Japan

In 32 volunteers, reproducibility of semiquantitative fat measurements of the liver using 3D gradient echo (MEDAL) and proton MR spectroscopy was evaluated between two measurements with about one-week interval. Correlation was also evaluated among MR acquisitions of MEDAL and proton MR spectroscopy, and CT. Good reproducibility was obtained with MEDAL and MR spectroscopy, respectively (p<0.001). Acceptable correlation was obtained between MEDAL and proton MR spectroscopy although less correlation was observed of MR against CT evaluations. Semiquantitative MR evaluations of fat liver are feasible in a short period, which might be used for evaluations of metabolic abnormalities.

2621. Reproducibility of Magnetic Resonance Elastography for Quantification of Hepatic Stiffness Catherine Diane Gard1, Jason P. Fine, Ethan K. Brodsky1, Scott B. Reeder1 1University of Wisconsin-Madison, Madison, Wisconsin, USA

Magnetic Resonance Elastography (MRE) has been shown to non-invasively quantify hepatic fibrosis, and the purpose of this work is to evaluate the reproducibility of MRE in the livers of healthy volunteers. In this work, 10 volunteers underwent two consecutive MRE exams, and results were assessed by two readers. Statistical analyses of intra- and inter-observer results have high correlation, minimal percent deviation, and differences were found to be statistically insignificant. For a single reader, changes greater than 7% stiffness would represent meaningful changes in longitudinal stiffness measurements. Thus, MRE is highly reproducible and displays minimal error across multiple exams and readers.

2622. Ultra-Fast Time Resolved Contrast Enhanced Abdominal Imaging Using an Elliptical Centric Fat Suppressed 3D Profile Sharing Acquisition Technique, SENSE and Partial Fourier Gabriele M. Beck1, Gwenael Herigault1, Anne-Sophie Glantenay1, Kenneth Coenegrachts2, Vincent Denolin3 1Philips Medical Systems, Best, Netherlands; 2AZ St.-Jan AV, Brugge, Belgium; 3Philips Medical Systems, Benelux, Belgium

The detection and characterization of hyper-vascular masses in abdominal organs like liver and pancreas is greatest during the hepatic arterial phase. 3D time resolved imaging provides an opportunity for these types of applications. It is the objective of current work to investigate a novel elliptical centric profile sharing acquisition technique that combines a fat suppressed turbo gradient echo sequence, SENSE, partial Fourier, keyhole imaging and an alternating viewsharing technique integrated in the keyhole part.

2623. Parallel Imaging in the Human Liver at 7 Tesla Angela Lynn Styczynski Snyder1, Steen Moeller1, Michael Garwood1, Patrick John Bolan1 1Center for Magnectic Resonance Research, University of Minnesota, Minneapolis, Minnesota, USA

Parallel imaging is synergistic with high magnetic field strength, making it possible to obtain better temporal and spatial resolution. Overcoming B1+

shimming challenges, high resolution, high quality liver imaging (1x1x2.5 mm) in a single breath hold is feasible using a 16 channel body array and a 1-dimensional reduction factor of 6.

Poster Sessions

430

2624. Free-Breathing, Fat-Suppressed T1-Weighted Imaging Using IR Prepared Dual-Echo FGRE with MEDAL Water/fat Separation Ken-Pin Hwang1, Jingfei Ma2 1General Electric Healthcare, Houston, Texas, USA; 2University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA

An inversion recovery prepared FGRE sequence can acquire a T1 weighted image in a single shot, freezing abdominal motion even when patients are breathing freely. One limitation of the sequence is that it is not directly compatible with commonly used fat suppression techniques. In this work, we modified the sequence to acquire both in-phase and out-of-phase images, and apply a recently developed Dixon algorithm (MEDAL) to produce separate water and fat images. We demonstrate that excellent T1 weighted images with uniform fat suppression can be obtained in patients who are unable to comply with breath-hold instructions.

2625. Multiple Phase CE-MRA of the Liver Using Time-Resolved 3DPR Ethan K. Brodsky1, David L. Isaacs1, Walter F. Block1, Scott B. Reeder1 1University of Wisconsin - Madison, Madison, Wisconsin, USA

Detection and characterization of hepatocellular carcinomas (HCCs) in cirrhotic patients is challenging due to their variable and rapid arterial enhancement. Multi-phase CE-MRI is commonly used, but suffers from limited temporal resolution (typically 20s/frame) and an inability to consistently match acquisitions to the desired phase of enhancement. We present a 3D non-Cartesian contrast-enhanced isotropic-resolution acquisition of the liver with real-time monitoring that significantly improves temporal resolution (as low as 1 s per 3D volume), allowing breath-holds to be matched to the desired enhancement phase, interpretation in any reformatted viewing plane, and retrospective selection of the temporal window showing optimal lesion contrast.

Pancreatic Imaging Hall D Wednesday 13:30-15:30

2626. Functional Perfusion Imaging of the Pancreas Using an Arterial Spin Labeling Technique Christina Schraml1, Petros Martirosian1, Nina F. Schwenzer1, Andreas Boss1, Claus D. Claussen1, Fritz Schick1 1University Hospital of Tuebingen, Tuebingen, Germany

Arterial-spin-labeling perfusion imaging is a reliable, non-invasive MR technique for the assessment of tissue perfusion working without any contrast media administration. The aim of the study was to test the feasibility of MR perfusion imaging of the pancreas before and after oral stimulation using a FAIR-TrueFISP approach. Perfusion maps of diagnostic quality could be created by means of the extended Bloch equations. Significant stimulation-related changes in organ perfusion could be demonstrated. The method may provide important information in the assessment of acute and chronic inflammatory pancreatic diseases, endocrine and exocrine pancreatic function disorders and for monitoring of pancreatic transplants.

2627. Assessment of the Pancreas with MR Elastography Meng Yin1, Sudhakar K. Venkatesh2, Roger C. Grimm1, Phillip J. Rossman1, Armando Manduca1, Richard L. Ehman1 1Mayo Clinic, Rochester, Minnesota, USA; 2National University of Singapore, Singapore

Chronic pancreatitis is a progressive and destructive inflammatory process of the pancreas resulting in necrosis and fibrosis. MR Elastography (MRE) is a potential non-invasive diagnostic tool for detecting emergence of fibrosis in chronic pancreatitis. In this study, we implemented a 7D MRE technique and a 3D LFE inversion algorithm to estimate shear stiffness in normal pancreatic parenchyma. The average shear stiffness of the pancreas tissue was 2.0±0.4 kPa in a series of ten normal volunteers. Preliminary results demonstrate that assessment of the pancreas with MRE technique is feasible, offering the prospect of a new non-invasive method for assessing chronic pancreatitis.

2628. Pancreatic Iron Overload in Thalassemia Patients: T2* MRI Evaluation – Initial Experience Orly Goitein1, Eli Konen1, Eliezer Rachmilewitz2, Tammar Kushnir1 1The Chaim Sheba Medical Center, Tel Hashomer, Israel; 2The Edith Wolfson Medical Center, Holon, Israel

Iron deposition in hepatic, myocardial and endocrine gland tissues is a known complication in multitransfused Thalassemia patients. Pancreatic siderosis can affect both endocrine and exocrine functions. In addition, diabetes has been related to excess pancreatic iron deposition, besides increased peripheral insulin resistance. T2* MRI mapping was used to assess, for the first time, pancreatic iron levels of Thalassemia patients compared with normal subjects. Pancreatic T2* values were found to be significantly lower in all Thalassemic patients. Pancreatic data is an important addition to the arsenal of non invasive iron evaluation, allowing better understanding of the full spectrum of iron pathophysiology.

2629. Manganese Enhanced Magnetic Resonance Imaging (MEMRI) of Endogenous Rodent Pancreas Activation Muhammad E. Haque1, 2, Erica Markiewicz1, Suraj Serai3, Matt Zuckerman1, Lara Leoni1, Brian B. Roman1 1University of Chicago, Chicago, Illinois, USA; 2George Mason University, Fairfax, USA; 3University of Illinois, Chicago, Chicago, USA

Presently pancreatic endocrine function is assessed using biochemical tests of organ output or indirectly by measuring serum glucose levels. Recently manganese enhanced imaging (MEMRI) has been used to study brain activation and we propose that similar paradigms can be applied to assess the function of the endogenous pancreas. To overcome several difficulties in the application of MEMRI to the pancreas, we used fast magnetization prepared rapid gradient echo (MP-RAGE). Rats were infused with MnCl2 followed by an IV glucose challenge to activate the pancreas. Images were obtained pre and post Mn infusion as well as post glucose stimulation. Mn and Glucose stimulation resulted change in image contrast.

Poster Sessions

431

Lung MRI Hall D Thursday 13:30-15:30

2630. Improved Visualization of Delayed Contrast Agent Bolus Onset in Pulmonary Perfusion MRI Frank Risse1, Michael Puderbach1, Monika Eichinger1, Hans-Ulrich Kauczor1, Wolfhard Semmler1 1Deutsches Krebsforschungszentrum, Heidelberg, Germany

The temporal information of three-dimensional (3D) dynamic contrast-enhanced MRI is not usually used to read lung perfusion images. Subtraction images are generated instead, but this might mask perfusion in case of a delay. The aim, therefore, is to demonstrate a simple analysis strategy by computing parameter maps for the lung without omitting temporal information, thus enabling improved visualization of the results. It has been shown that subtraction images might mask the real underlying perfusion conditions. Based on the results, perfusion was classified into five subgroups.

2631. Whole-Body MR Examination for M-Stage Assessment in Non-Small Cell Lung Cancer: How to Use Whole-Body Diffusion-Weighted Imaging as Compared with Integrated FDG-PET/CT Yoshiharu Ohno1, Yumiko Onishi, 12, Hisanobu Koyama1, Munenobu Nogami, 12, Daisuke Takenaka1, Takeshi Yoshikawa, 13, Sumiaki Matsumoto1, Kazuro Sugimura1 1Kobe University Graduate School of Medicine, Kobe, Japan; 2Institute of Biomedical Research and Innovation, Kobe, Japan; 3Konan Hospital, Kobe, Japan

In this study, we attempted to validate the hypothesis that whole-body MR imaging with DWI has potential as an alternative technique for the detection of distant metastases in NSCLC patients with a capability similar to that of integrated FDG-PET/CT. To this end, we prospectively and directly compared the capability of whole-body MR imaging with and without DWI and of integrated FDG-PET/CT for M-stage assessment in NSCLC patients, and to determine the utility of whole-body DWI as a component of whole-body MR examination for detection of metastases.

2632. Pulmonary MRI vs. Thin-Section MDCT: Capability for Nodule Detection and Diagnosis and for Assessment of Influence to Survival Hisanobu Koyama1, Yoshiharu Ohno1, Hideaki Kawamitsu2, Atsushi Kono1, Daisuke Takenaka1, Masahiko Fujii2, Kazuro Sugimura1 1Kobe University Graduate School of Medicine, Kobe, Japan; 2Kobe University Hospital, Kobe, Japan

Since 1997, several investigators have reported the capability of pulmonary MRI for nodule detection as compared with CT, and tried to demonstrate possibility for substitution to CT. However, no direct comparison between pulmonary MRI and MDCT have been reported. We hypothesized that pulmonary MRI has potential for detect and diagnose pulmonary nodules without significant degradation of detection rate for malignant nodules, diagnostic accuracy and survival rate, when compared with MDCT. The purpose of our study was to compare capability for nodule detection and diagnosis and for affection to survival between pulmonary MRI and MDCT.

2633. The Use of Color Intensity Projections (CIPs) for Visualizing Pulmonary Perfusion Parameters with Preservation of Anatomy Jan G. Korporaal1, 2, J. Tim Marcus1, Heleen Rietema, Keith S. Cover1, Anton Vonk Noordegraaf 1VU University Medical Center, Amsterdam, Netherlands; 2Utrecht University Medical Center, Netherlands

In dynamic contrast-enhanced pulmonary perfusion, the Color Intensity Projection (CIP) is constructed by pixel: the hue (wavelength of color) is determined by the time to peak enhancement, the saturation of color by the contrast enhancement ratio, and the brightness by the maximum signal intensity over time. The feasability of CIP was demonstrated in a patient with emboli and a patient with obstructed left pulmonary artery. The CIP yields one comprehensive functional perfusion image, where underlying anatomic structures of well-perfused lung areas and blood vessels are automatically distinguishable by high saturation and brightness.

2634. Comparison of Pixel-By-Pixel Compartment Modeling and Deconvolution Analysis for Pulmonary Perfusion Measurements Michael Ingrisch1, Ulrike Attenberger1, Steven Sourbron1, Olaf Dietrich1, Frank Risse2, Maximilian Reiser1, Christian Fink3 1Klinikum Großhadern, Munich, Germany; 2Deutsches Krebsforschungszentrum, Heidelberg, Germany; 3Klinikum Mannheim, Mannheim, Germany

Dynamic contrast-enhanced MRI allows the assessment of pulmonary perfusion. We investigate the feasibility of a pixel-by-pixel analysis of pulmonary perfusion using a one-compartment model in healthy volunteers. The results were compared with a more commonly used deconvolution approach. The results indicate that a one-compartment-model describes the data sufficiently and, in agreement with literature, yields higher flow values than deconvolution analysis.

2635. Comparison of Two Gadolinium Contrast Agents for Lung Perfusion MRI Paul Armitage1, Neil Woodhouse2, David Kiely3, Paul Griffiths2, Jim M. Wild2 1University of Edinburgh, Edinburgh, UK; 2University of Sheffield, Sheffield, UK; 3Royal Hallamshire Hospital, Sheffield, UK

With the development of faster imaging sequences, MR contrast enhanced lung perfusion imaging has become feasible in the clinical setting and shows great promise as a non-ionizing alternative to a nuclear scintigraphy lung perfusion scan. In this work, a visual and quantitative comparison is made between perfusion maps of the lung acquired using two different gadolinium-based paramagnetic contrast agents.

Poster Sessions

432

2636. Comparison of High-Resolution and Time-Resolved MRA in a Rabbit Model of Pulmonary Embolism at 1.5 and 7 Tesla Jaime Mata1, Ugur Bolzar1, John Mugler III1, Colleen Schamber1, Wilson Miller1, Stuart Berr1, Klaus Hagspiel1 1University of Virginia, Charlottesville, USA

High magnetic-field strengths potentially allow significant improvements for imaging many regions of the body due to the increase in signal-to-noise ratio, which can be traded for higher spatial resolution or shorter acquisition times. However, in the lungs, with their large number of air-tissue interfaces that result in strong localized field gradients induced by the magnetic-susceptibility differences, the use of magnetic resonance imaging at higher fields („d3.0T) may be limited. We evaluated the feasibility of using time-resolved and high-resolution contrast-enhanced MRA at 7T for characterizing an animal model of pulmonary embolism and compared the results with the same techniques at 1.5T.

2637. Validation of Quantification of Regional Pulmonary Blood Flow (PBF) Via Contrast Enhanced MRI Using Non-Linear Corrected AIF with H2

15O PET Daniel Neeb1, Rainer Peter Kunz1, Sebastion Ley2, Gabór Szábo3, Ludwig G. Strauss2, Hans-Ulrich Kauczor2, Karl-Friedrich Kreitner1, Wolfgang G. Schreiber1 1Mainz University Medical School, Mainz, Germany; 2German Cancer Research Center (DKFZ), Heidelberg, Germany; 3University of Heidelberg, Heidelberg, Germany

Nine healthy pigs were examined using MRI and H215O PET imaging. Calculation of PBF was based on a model of freely diffusible tracers (PET) and indicator dilution theory (MR). A sequence-dependent correction for non-linearity in the AIF was developed for the MR data. ROI analysis confirmed a statistically highly significant correlation (p < 0.001) between blood flow values obtained from PET and MR and a good linear relation when utilizing the proposed AIF correction methdology. Deviations from the ideal case appear to be explained by the study design (delay between measurements) and methodologic aspects (respiratory status, different slice thickness).

2638. Utility of the Optical Flow Method for Motion Tracking in the Lung Chun Xu1, Ke Zhang, 12, Lawrence Dougherty1, 1, Abram Voorhees1, 1, Qun Chen, 12 1; 2New York University, New York, New York, USA

MRI spirometry is technique that has been demonstrated to non-invasively measure pulmonary function on a regional basis. Using real-time imaging of the lung during forced breathing maneuvers, this method is able to calculate regional physiologic measures, such as FVC, FEV1, and the time constant tau. Relevant for assessing heterogeneous pulmonary disorders, this technique has shown the ability to examine lung function with a resolution currently unavailable from commonly used non-invasive procedures. This paper examines the improved motion tracking results of using the optical flow method to assess lung deformation.

2639. Time Resolved Lung Ventilation Imaging by Fourier Decomposition Michael Deimling1, Vladimir Jellus1, Bernhard Geiger, Christophe Chefd'hotel 1Siemens Medical Solutions, Erlangen, Germany

Lung ventilation is measured without any endogenic media by using the density variation of registered lung tissue. A very fast SSFP sequence is used to generate a time-resolved 2D-lung data stack. Fourier transform along the time axes will allow the separation of breathing or ventilated regions from disturbing signals due to the pulsating blood within the lung tissue. The description of the pathologic breathing pattern, seems possible with this spectral decomposition technique.

2640. Quantitative Assessment of Deposition Patterns of Inhaled Particulate Matter by MRI Miriam Scadeng1, Ellen C. Breen1, G Kim Prisk1, David J. Dubowitz1, Chantal Darquenne1 1UCSD, San Diego, California , USA

Exposure to airborne particulate matter and its implications in human health are a major concern as more evidence links air pollution with morbidity and mortality. Understanding of the fate of aerosols in the human lung is also important in medical applications such as inhalation drug therapy, and threats of biological warfare. We describe a quantitative technique to determine the distribution of airborne particles in the respirable range in an animal model using MRI that could be used to study healthy or diseased lungs.

2641. Method for Correction of Breathing-Dependent Signal Changes in Dynamic Lung Oxygen-Enhanced MRI – Improved Sensitivity in Smokers Deirdre Maria McGrath1, Josephine Naish1, Chris Taylor1, Charles Hutchinson1, Geoff Parker1 1University of Manchester, Manchester, UK

Oxygen-enhanced lung MRI is hampered by intrinsically low proton density, the large susceptibility differences caused by the air-tissue interfaces, and respiratory and cardiac motion. To avoid the effects of breathing motion in dynamic studies breath-holding, gating or post-registration is required. Registration is preferable, as gating is not ideal for maintaining temporal resolution and breath-holding may distort the processes being measured, and is not well tolerated. We present a novel corrective method for breathing-dependent signal changes applied to data from a free-breathing dynamic protocol with post-registration, and demonstrate how the correction improves sensitivity of the oxygen wash-in time characteristic in smokers.

2642. SSFP Based High Resolution 19F Imaging of the Rat Lung Ex Vivo with FC84 Dominik von Elverfeldt1, Philipp Emerich1, Julia Weigel1, Dominik Paul1, Daniel Steinmann1, Matthias Schneider1, Hanna Runck1, Claudius Stahl1, Josef Guttmann1, Jochen Leupold1 1University Hospital Freiburg, Freiburg, Germany

Besides its therapeutic effect partial liquid ventilation using perfluorocarbons has the potential of susceptibility reduced lung imaging and the possibility to monitor oxygen turnover. So far these options have been used in pig lungs at 1.5 T using 19F imaging. In the rat lung the beneficial susceptibility effect on 1H MRI using PLV with water-perfluorcarbon emulsions was shown. This work demonstrates the potential of a SSFP based high resolution sequence in 19F MRI on excised rat lungs at 9.4 T.

Poster Sessions

433

Hyperpolarized Gas Lung MRI Hall D Monday 14:00-16:00

2643. Sequence Considerations for 2D Radial MRI of Hyperpolarized Gases Jim M. Wild1 1University of Sheffield, Sheffield, UK

Radial MRI of hyperpolarized (HP) 3He gas has shown to be effective in imaging ventilation dynamics in the human lungs. With angular undersamping, the number of views, can be reduced in favour of increased temporal resolution, provided the streak artifacts (spatially correlated noise) can be tolerated. In this work, factors effecting the SNR, spatial resolution and streak prevalence in undersampled short TE spoiled radial imaging are considered for HP gas MRI. Simulations of the effect of gradient diffusion dephasing and RF undersampling for constant and variable flip angle radial schemes are presented and compared with experiments in gas phantoms and human lungs with HP 3He.

2644. Rapid Three-Dimensional Hyperpolarized 3He Imaging of the Lung Using an Optimized Steady-State Free-Precession Pulse Sequence: Increased SNR Without Off-Resonance Banding Artifacts John P. Mugler, III1, G Wilson Miller1, Talissa A. Altes, 12, Jaime F. Mata1, Eduard E. de Lange1, William A. Tobias3, Gordon D. Cates, Jr1, 3, James R. Brookeman1 1University of Virginia School of Medicine, Charlottesville, Virginia , USA; 2Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA; 3University of Virginia, Charlottesville, Virginia , USA

This work describes an optimized implementation of a 3D-SSFP pulse sequence for ventilation imaging of the lung using hyperpolarized helium-3. By using a TR less than 2 ms, this optimized technique suppresses intensity banding artifacts that were seen with earlier 2D implementations of SSFP imaging. In addition, the 3D-SSFP sequence yields 3-4 times higher SNR than widely-used low-flip-angle spoiled-GRE methods, and thus requires a much lower dose of hyperpolarized gas than a comparable spoiled-GRE acquisition. High-quality reconstructions in any image plane are obtained in an acquisition time of less than 10 s.

2645. Airway Measurement in 3D Using Dynamic Hyperpolarized He-3 Multi-Echo VIPR Eric T. Peterson1, James H. Holmes1, Sean B. Fain1 1University of Wisconsin - Madison, Madison, Wisconsin, USA

A high temporal resolution VIPR (3D PR) acquisition using hyperpolarized helium-3 was combined with a multi-step airway measurement algorithm combining airway segmentation, calculation of the centerline axis, lung airway measurement of diameter and branch angle. The high temporal resolution and high contrast of the acquisition allows for similar measurement of airways to the 3rd generation with values within 25% of those measured with multi-detector CT. Results approach the quality of commercially available CT airway segmentation packages for the large airways.

2646. Diffusion Tensor Imaging of the Rat Lung Using Hyperpolarized 3He Timothy Mark Taves1, 2, Alexei V. Ouriadov1, Giles Edmund Santyr1, 2 1Robarts Research Institute, London, Canada; 2University of Western Ontario, London, Canada

Gas diffusion anisotropy and magnitude information may be valuable in the specification of lung disease. Diffusion Tenor Imaging (DTI) provides full diffusion information. DTI of a capillary phantom and a rat lung was performed using hyperpolarized 3He. Diffusion ellipsoid maps were reconstructed to verify that the gas diffuses predominantly along the capillaries and airways as expected. Trace maps of the lungs were also reconstructed to show that the magnitude of diffusion is greatest in the upper airways as expected.

2647. Three Dimensional Imaging of Ventilation Dynamics in Asthmatics Using HYPR ME-VIPR James H. Holmes1, Rafael L. O'Halloran1, Eric T. Peterson1, Ethan K. Brodsky1, Janet E. Kuhlman1, Nizar N. Jarjour1, Sean B. Fain1 1University of Wisconsin-Madison, Madison, Wisconsin, USA

The use of a multi-echo vastly undersampled isotropic projection acquisition (ME-VIPR) is used to accelerate data acquisition in hyperpolarized (HP) He-3 lung imaging of asthma patients. This technique coupled with a HYPR reconstruction allowed 3D dynamic lung imaging. Further, this technique can retrospectively accommodate lost patient breath-holds to maximize image quality. Imaging results are quantified using the percent ventilated volume and validated with spirometry and MDCT. Further, detection of differential filling is shown.

2648. Simulation of Temporal Resolution for Non-Cartesian K-Space Sampling Strategies to Trace Fast Dynamic Changes of Helium-3 Spin Density Maxim Terekhov1, Julien Rivoire1, Wolfgang Schreiber1 1Mainz University Medical School, Mainz, Germany

The increase of the temporal resolution is for many years one of the issues in dynamic MRI -imaging of lung ventilation with hyperpolarized gases. One of the ways known to solve this problem is the use of non-cartesian schemes of k-space sampling (radial or spiral). However, the artefacts originated from the sophisticated image reconstruction schemes of these methods makes unclear their real timing efficiency. Additional complications also come from using of the “sliding-window” technique. To examine the time resolving effectiveness of different sampling strategies under conditions of dynamic imaging, the numerical simulations were done. The generated initial spin density matrix was affected by the temporal modulation of intensity. Different interleaving strategies were tested to provide the closest tracing of spin density modulation function with intensity of reconstructed images.

Poster Sessions

434

2649. Validation of Regional Compliance Measurement Using Hyperpolarized 3He MRI in a Syringe Lung Phantom Vahid Vadhat1, Kiarash Emami1, John MacDuffie Woodburn1, Robert V. Cadman1, Jiangsheng Yu1, Hans Hyonchang Kim1, Masaru Ishii, 12, Rahim R. Rizi1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA; 2Johns Hopkins University, Baltimore, Maryland, USA

A phantom study was performed for preliminary validation of a regional compliance measurement technique using dynamic ventilation method. Using this measurement technique, the fractional ventilation value, in a 10-mL glass syringe simulating a single lung voxel was obtained. The validity of the fractional ventilation value through direct measurement is used to calculate compliance and was tested by comparing it to the theoretical value.

2650. The Role of Collateral Pathways in Long-Range 3He Diffusion Jason C. Woods1, Seth-Emil Bartel1, Susan E. Haywood1, Yulin V. Chang2, Dmitriy A. Yablonskiy1, David S. Gierada1, Mark S. Conradi1 1Washington University, St Louis, Missouri, USA; 2Children's Hospital of Pennsylvania, Philadelphia, Pennsylvania, USA

In order to determine the role of collateral routes in measurements of the long-range 3He diffusion coefficient (LRDC), we simulated LRDC in a human lung with no collateral pathways, made closed-form calculations in a simple lung model, and measured LRDC in human lungs and porcine lungs (with little collateral ventilation). The robustly-tested simulations resulted in an LRDC 20 times lower than measured in human lungs; calculations revealed that a surprisingly small number of holes through alveolar walls can increase LRDC to measured values, and LRDC in porcine lungs was 4x smaller than in humans, confirming the role of collateral pathways in health.

2651. A Theory of Diffusion Time Dependence of ADC in Hyperpolarized 3He Lung MRI. Millisecond Range Alexander L. Sukstanskii1, Dmitriy A. Yablonskiy1 1Washington University, St. Louis, USA

Lung diffusion MRI with hyperpolarized 3He gas provides information on lung structure and function. Substantial increases in ADC have been reported in emphysema suggesting that 3He gas ADC could serve as a biomarker for disease progression. However, even in healthy human lungs ADC exhibits rather broad variability, with different studies reporting results between 0.15 cm2/s and 0.25 cm2/s. Here we provide a theoretical analysis demonstrating a significant diffusion time dependence of ADC, even for diffusion times on the order of several milliseconds, which can explain the observed ADC variability.

2652. Anatomical Trends in Coregistered ADC and T2* Maps of 3He Gas in the Lungs of Healthy Normals Salma Ajraoui1, Rob Ireland1, Kuan J. Lee1, Neil Woodhouse1, Jim M. Wild1 1University of Sheffield, Sheffield, UK

Measurement of the 3He gas ADC with pulsed gradient methods can be used to infer spatial dimensions at the alveolar level, and a gradient in the 3He ADC in the anterior-posterior direction has previously been reported in healthy normals. The 3He T2* is a second parameter which will depend upon the alveolar dimensions as these define the microscopic susceptibility gradients in which the gas is diffusing. Field strength, macroscopic B0 field homogeneity, adjacent blood perfusion (microscopic susceptibility difference) and degree of gas diffusion will also play a role in T2*. In previous work at 1.5T the 3He T2* was found to increase with lung volume (inflation of the alveoli). In this work 3He ADC and T2* data was collected from spatially registered 2D slices in four volunteers and the spatial trends within the lungs of the two parameters was investigated.

2653. Diffusion Weighted ³He-MRI in the Assessment of Pulmonary Emphysema: A Regional Evaluation Klaus Kurt Gast1, Christa Gast1, Trine Stavngaard2, Jim M. Wild3, Lise Vejby Soegaard4, Joerg Schmiedeskamp5, Christoph Dueber1, Wolfgang Guenter Schreiber1, Hans-Ulrich Kauczor6, Edwin JR van Beek7, Claus Peter Heussel8 1Johannes Gutenberg University Hospital, Mainz, Germany; 2Rigshospitalet Copenhagen University Hospital, Copenhagen, Denmark; 3University of Sheffield, Sheffield, UK; 4Hvidovre University Hospital, Hvidovre, Denmark; 5Max Planck Institute for Polymer Research, Mainz, Germany; 6German Cancer Research Center, Heidelberg, Germany; 7Carver College of Medicine, University of Iowa Hospitals and Clinics, Iowa City, USA; 8Thoraxklinik Heidelberg, Heidelberg, Germany

Although the utility of diffusion weighted ³He-MRI in pulmonary emphysema has been shown, correlation to HR-CT was limited. A possible reason for this discrepancy may be related to regional inhomogeneity of the disease. In this regional evaluation, correlation between ADClocal and MLDlocal was r=0.24 in COPD, r=0.71 in alpha-1-antitrypsin deficiency and r=0.48 in healthy volunteers. Local hyperinflation with collapse of neighbouring alveoli, overlying infections and perfusion inhomogeneity are possible explanations for the methods’ unequivocal results. It is postulated that diffusion weighted ³He-MRI shows the function of a lung area while CT provides morphologic information with possible influence of concomittant disease.

2654. Lung Function Decline Over 5 Years as Measured by the Hyperpolarized Helium-3 ADC in Smokers Talissa A. Altes1, 2, Chengbo Wang1, Michael Salerno3, Eduard E. de Lange2, Kai Ruppert1, 2, John P. Mugler, III2 1Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA; 2University of Virginia, Charlottesville, Virginia , USA; 3Duke University, North Carolina, USA

Six subjects at risk for or with mild COPD underwent hyperpolarized helium-3 diffusion MRI and spirometry on two occasions separated by 5.4 to 6.7 years. The average percent change in mean ADC, FEV1 %predicted and FEV1/FVC was 10%, 5% and -11%, respectively. The average rate of decline was 0.031cm2/s/yr for mean ADC, and 23mL/yr for FEV1. There was a strong correlation between mean ADC at baseline and percent change in mean ADC, FEV1, and FEV1/FVC (r = -0.83, -0.86, and -0.92, respectively), suggesting that elevated baseline mean ADC values are associated with a more rapid decline in lung function.

2655. Assessment of Longitudinal Changes of Lung Function and Structure Pre– and Post– Lung Volume Reduction Surgery in a Rat Elastase Model of Emphysema Masaru Ishii1, 2, Kiarash Emami2, Jianliang Zhu2, John MacDuffie Woodburn2, Stephen Kadlecek2, Michael E. Friscia2, Jiangsheng Yu2, Hans Hyonchang Kim2, Joseph B. Sharger2, Warren B. Gefter2, Rahim R. Rizi2 1Johns Hopkins University, Baltimore, Maryland, USA; 2University of Pennsylvania, Philadelphia, Pennsylvania, USA

Lung volume reduction surgery (LVRS) is used to improve respiratory mechanics in severe forms of emphysema. Proper patient selection schemes still remain unclear. We show using hyperpolarized helium MRI measures of lung function and microstructure and a longitudinal cohort study that LVRS’s improvement in function is a macroscopic phenomena and that it is applicable to subjects with homogenous forms of emphysema.

Poster Sessions

435

2656. Assessment of Peripheral Airways Development After Preterm Birth by Hyperpolarised 3He Marius Ovidiu Mada1, John R. Owers-Bradley1, Manjith Narayanan2, Mike Silverman2, Jau-Yi Wang1, Caroline S. Beardsmore2 1University of Nottingham, Nottingham, UK; 2University of Leicester, Leicester, UK

Premature born children suffer from altered lung development and function. We compared (in vivo) measurements of acinar structure in children born preterm with healthy controls using the techniques of hyperpolarised 3He MR (HPHe3MR) and Multiple Breath Nitrogen Washout (MBNW). When compared to controls, children born preterm have a trend towards differences in spirometry but have markedly higher ventilatory inhomogeneity in their acinar airways. Lung damage at the alveolar level normally leads to higher ADC as the gas can diffuse more freely so we hypothesised that ADC would be higher in children born preterm. The lack of a difference between preterm and control groups suggests that the acinar changes are not related to abnormal structure at the alveolar level. The ADC sometimes exhibits an inhomogeneous distribution across the lungs, more commonly in girls. Extending the study to children of other age groups could clarify whether this inhomogeneity is related to puberty.

2657. Diffusion Time: A Tuning Parameter for Lung Airspace Size Selection with Hyperpolarized 3He Gas Diffusivity Measurements? Dattesh D. Shanbhag1, Talissa A. Altes2, Jack Knight-Scott3 1GE Global Research, Bangalore, India; 2The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA; 3Children's HealthCare of Atlanta, Atlanta, Georgia, USA

The diffusion signal attenuation, in restricted environments of lung airspaces is function of the effective observation time or diffusion time (δ) and the diffusion gradient area. If the latter is fixed, then δ can be possibly used to traverse different geometrical structures. In present work, we investigated the effects of variable δ on diffusion measurements of 3He gas in vivo in lungs. In all volunteers (N = 3), it was noticed that rms displacements (indicative of airspace sizes) increased in quadratic manner with increasing δ. No asymptotic value was reached, suggesting diffusion in lung airspaces is hindered, not restricted.

2658. Reliability Evaluation of Hyperpolarized 3He Gas Diffusion Models in Lungs in Vivo: Wide Range B-Value Space Dattesh D. Shanbhag1, Talissa A. Altes2, Jack Knight-Scott3 1GE Global Research, Bangalore, India; 2The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA; 3Children's HealthCare of Atlanta, Atlanta, Georgia, USA

The study was aimed to evaluate the reliability and failure modes of various models currently used to obtain information about lung microstructure in vivo using hyperpolarized 3He gas diffusion as probe. The models were tested for wide range of b-values from 0.2 s/cm2 to 52 s/cm2 in 14 healthy volunteers and 3 COPD patients. A critical cutoff b-value of 20 s/cm2 was identified, which separated the performance of most models in two regions. 1.b < 20 s/cm2 : Greater differences observed between healthy volunteers and COPD patients 2.b > 20 s/cm2 increased confidence for diffusion measurements albeit with reduced sensitivity.

2659. Effect of Finite Gradient Width on Hyperpolarized 3He Gas Lung Q-Space Diffusion Spectroscopy in Vivo Dattesh D. Shanbhag1, Talissa A. Altes2, Jack Knight-Scott3 1GE Global Research, Bangalore, India; 2The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA; 3Children's HealthCare of Atlanta, Atlanta, Georgia, USA

Q-space diffusion formalism assumes SGP condition, which is violated on clinical scanners due to the finite rise time of gradient systems. In this work, we examined effects of diffusion gradient width (δ) on q-space parameters and its implication on measurements of lung airspaces in healthy volunteers and COPD patient. As the δ increased, it was noticed that the displacement probability profile became narrower, with concomitant decrease in rms displacement. On an average, the rms displacements decreased by 11-15% for a change in δ by 1 ms. We conclude that on clinical systems, the measured lung airspace sizes are typically under-estimated.

2660. S/V Measurements in a 3He Bead Phantom Using a Short-Time-Scale NMR Diffusion Sequence Michael Carl1, G Wilson Miller1, John Paul Mugler III1, William Al Tobias1, Gordon Dell Cates1 1University of Virginia, Charlottesville, Virginia , USA

We used a specialized short-time-scale diffusion NMR technique to measure S/V. The pulse sequence is based on a technique introduced by our group last year and involves concatenating a large number of bipolar diffusion-sensitizing gradients to increase the diffusion attenuation of the MR signal while maintaining a fundamentally short diffusion time. Periodic refocusing RF pulses were added to the sequence to extend the signal duration in more hostile environments with short T2*. The features of this technique are explored using Monte-Carlo simulations of gas diffusion in various geometries and experimental diffusion measurements in a bead phantom containing 3He gas.

2661. Posture Dependent Effects on Human Pulmonary Oxygen Partial Pressure Rachel Nora Scheidegger1, 2, Dan Chonde, 12, Leo Lee Tsai, 23, Matthew Scott Rosen1, 4, Samuel Patz, 35, Ross William Mair1, Ronald Lee Walsworth1, 4 1Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts, USA; 2Harvard-MIT Division of Health Sciences and Technology, Cambridge, Massachusetts, USA; 3Harvard Medical School, Boston, Massachusetts, USA; 4Harvard University, Cambridge, Massachusetts, USA; 5Brigham and Women's Hospital, Boston, Massachusetts, USA

The lung is exquisitely sensitive to gravity and posture, yet current imaging systems restrict subjects to horizontal positions only. Our open-access human MRI system permits the study of pulmonary function with subjects in a variety of postures. Using this system, we have studied human pAO2 in subjects in both vertical and supine positions. Our results show clear gradients in pAO2 from the top to bottom of the lung, in agreement with the “zones of the lung” model of West. The standard deviation of pAO2 values when vertical was higher than that when horizontal (11.6 torr vs. 6.4 torr, respectively).

Poster Sessions

436

2662. Multi-Slice PO2-Weighted 3He Imaging in a Rabbit Model of Regionally Impaired Perfusion G. Wilson Miller1, Ugur Bozlar1, Jaime F. Mata1, Colleen M. Schamber1, John P. Mugler III1, Gordon D. Cates1, Klaus D. Hagspiel1 1University of Virginia, Charlottesville, USA

PO2-weighted 3He MRI was performed in a rabbit model of reversible pulmonary embolus. The goal was to observe PO2-weighted contrast, rather than obtain quantitative measurements of absolute PO2, allowing multiple 2D slices to be acquired in the same breath hold without concern that inter-slice gas diffusion would corrupt the PO2 measurement. Images clearly showed regions of elevated PO2 corresponding to the location of obstructed perfusion. These lesions resolved when perfusion was restored.

2663. Measurement of Pulmonary Partial Pressure of Oxygen and Oxygen Depletion Rate with Hyperpolarized Helium-3 MRI: A Preliminary Reproducibility Study on Pig Model Jiangsheng Yu1, Sheeva Rajaei1, Michelle Law1, Masaru Ishii, 12, Stephen Kadlecek1, Kiarash Emami1, Vahid Vadhat1, John MacDuffie Woodburn1, Richard A. Guyer1, Hans Hyonchang Kim1, Warren Gefter1, Rahim R. Rizi1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA; 2Johns Hopkins University, Baltimore, Maryland, USA

Pulmonary partial pressure of oxygen (pO2) and oxygen depletion rate (R) are two important parameters of lung function. This work presents a preliminary reproducibility study on a pig model. In the in-vivo animal experiments, four normal Yorkshire pigs were scanned. The global statistical analyses show that average variation of global mean is 9.7% for pO2 and 28.9% for R, and that the average variation of percentiles (10th, 25th, 50th, 75th and 90th) and inter-quartile range is 15.0% for pO2 and 34.9% for R. The region-of-interest analysis on the manually-selected regions shows that the average variation of mean is 11.3% for pO2 and 23.4% for R.

2664. A New Acquisition Scheme for Simultaneous Measurement of Fractional Ventilation, Apparent Diffusion Coefficient and Partial Pressure of Oxygen Jiangsheng Yu1, Stephen Kadlecek1, Kiarash Emami1, Masaru Ishii, 12, Vahid Vadhat1, John MacDuffie Woodburn1, Michelle Law1, Richard A. Guyer1, Hans Hyonchang Kim1, Warren Gefter1, Rahim R. Rizi1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA; 2Johns Hopkins University, Baltimore, Maryland, USA

In this work, we present a new acquisition scheme for simultaneously measuring fractional ventilation, apparent diffusion coefficient (ADC) and partial pressure of oxygen (pO2) with hyperpolarized 3He MRI. The new acquisition scheme consists of two parts. The first part is a typical ventilation sequence, in which several breaths of 3He gas are used for fractional ventilation measurement; at the end of the last inhalation of 3He, the breath is held for a single acquisition measurement of ADC and pO2. The ventilation measurement ends with a high concentration of 3He gas in the lung, which yields a high signal-to-noise ratio for ADC and pO2 measurement. We demonstrated this technique on an in-vivo rabbit experiment.

2665. High Resolution Measurement of Regional Alveolar Partial Pressure of Oxygen in the Mouse Lung by Hyperpolarized 3He MRI Kiarash Emami1, John MacDuffie Woodburn1, Richard A. Guyer1, Stephen Pickup1, Stephen Kadlecek1, Masaru Ishii, 12, Robert V. Cadman1, Jiangsheng Yu1, Hans Hyonchang Kim1, Michael Stephen1, Warren B. Gefter1, Rahim R. Rizi1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA; 2Johns Hopkins University, Baltimore, Maryland, USA

An implementation of a technique for measurement of regional alveolar partial pressure of oxygen in the mouse lung with an unprecedented resolution using hyperpolarized 3He MRI is demonstrated.

2666. High Resolution Measurement of Regional Ventilation in the Mouse Lung by Hyperpolarized 3He MRI Kiarash Emami1, John MacDuffie Woodburn1, Richard A. Guyer1, Stephen Pickup1, Stephen Kadlecek1, Masaru Ishii, 12, Robert V. Cadman1, Jiangsheng Yu1, Hans Hyonchang Kim1, Michael Stephen1, Warren B. Gefter1, Rahim R. Rizi1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA; 2Johns Hopkins University, Baltimore, Maryland, USA

An implementation of a technique for high-resolution measurement of regional ventilation in the mouse lung using hyperpolarized 3He MRI is demonstrated and results are compared to an earlier technique.

2667. Measurement of Regional Ventilation in Large Animals by Hyperpolarized 3He MRI: One Step Closer to Human Studies Kiarash Emami1, Stephen Kadlecek1, John MacDuffie Woodburn1, Jiangsheng Yu1, Vahid Vadhat1, Masaru Ishii, 12, Robert V. Cadman1, Hans Hyonchang Kim1, Michael Stephen1, Warren B. Gefter1, Rahim R. Rizi1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA; 2Johns Hopkins University, Baltimore, Maryland, USA

A new method to measure regional ventilation using hyperpolarized 3He MRI is proposed and its application in large animals is demonstrated. Small quantities of helium-3 gas and much shorter acquisition time compared to earlier methods promotes imminent implementation of this noninvasive technique in humans.

2668. Hyperpolarized Helium-3 Ventilation Imaging Under Spontaneous Breathing Conditions in Mice Hasan ALSAID1, Elise Bannier1, Vasile Stupar1, Katarzyna Cies´lar1, Sophie Gaillard1, Emmanuelle Canet-Soulas1, Yannick Crémillieux1 1Université Lyon1, Creatis-LRMN, CNRS, UMR 5220, U630 INSERM, ESCPE,, Villeurbanne, France

Hyperpolarized 3He ventilation imaging studies in mice have been performed using either animal tracheotomy or intubation protocols combined with assisted ventilation. These approaches are invasive and traumatic for animals and might not be suited for multiple, longitudinal assessments of animal lung function. Recently, Hyperpolarized 3He ventilation imaging was demonstrated in rabbits and rats under free breathing conditions. This approach is more challenging in mice because of small lung tidal volume and high respiratory rates. In this work, we developed and applied a non-invasive imaging protocol based on retrospective radial Cine imaging and sliding window technique under spontaneous mouse breathing conditions.

Poster Sessions

437

2669. Hyperpolarized 3He MR Imaging of Ventilation After Bacterial Lipopolysaccharide Exposure in Mice: A Model for Image-Guided Sampling of Ventilation Defects Abraham Thomas1, 2, James Voltz2, Boma Fubara1, Darryl Zeldin2, Bastiaan Driehuys1 1Duke University Medical Center, Durham, North Carolina, USA; 2National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA

Hyperpolarized 3He MRI is a powerful tool for visualizing ventilation defects in human subjects with asthma. Though ventilation defects have many postulated causes, their etiology is often unclear. To directly probe the origins of ventilation defects we utilized a lipopolysaccharide(LPS) instillation mouse model. LPS inhalation has been associated with the development of asthma and severity of the disease. In this study we created high-resolution 3He MR images to reveal defects associated with LPS-instillation and then used these images to specifically guide tissue sampling. We found that ventilation defects are dose-dependent and occur within 2 hours of LPS dosing.

2670. 3He MR Ventilation Imaging Under Spontaneous Breathing Condition in a Rodent Model of Broncho-Constriction Induced by Serotonin Karim Mosbah1, Vasile Stupar1, Yves Berthezène1, Nicolau Beckmann2, Yannick Crémillieux1 1Université Lyon 1, Lyon, France; 2Novartis Institutes for BioMedical Research, Basel, Switzerland

The purpose of this work is to assess in spontaneously breathing rats the bronchoconstriction induced by serotonin using a hyperpolarized 3He MR ventilation protocole.the SA (signal amplitude) and MSDR (maximum signal decay rate) parameters representing respectively the tidal volume and the expiratory gas rate were derived from dynamics image series.The findings of this study reflect the expected effects of the serotonin injection (decrease of the expiratory flow associated with a decrease of the tidal volume).

2671. 1H and HP 3He MR Imaging of LPS Treated Mice Lars E. Olsson1, Per Ola Önnervik2, Amir Smailagic2, Paul D. Hockings1 1AstraZeneca, Mölndal, Sweden; 2AstraZeneca, Lund, Sweden

The lungs of mice were examined 48 hours after LPS treatment using both 1H and hyperpolarized 3He MR imaging. Lesions on 3He images were characterized by ventilation defects. Correspondingly, lesions on 1H images were edema. The ventilation defects were often larger than the corresponding edema. The functional data provided by 3He add new information about the inflammation but in this study the imaging methods were equally sensitive.

2672. Hyperpolarized 3He Magnetic Resonance Imaging of Cystic Fibrosis :Initial Findings in Adults with Moderate and Good Lung Function and Comparison to Spirometry Yara Hosein1, Lindsay Mathew1, Andrew Wheatley1, Giles Edward Santyr1, Nigel Angus Morgan Paterson2, Grace Parraga1 1Robarts Research Institute, London, Canada; 2The University of Western Ontario, London, Canada

The overarching goal of this study is to identify new imaging intermediate endpoints of cystic fibrosis (CF) and then validate these as outcome measures for CF clinical trials. A number of new CF therapies are in development and feasible, sensitive, specific and precise measurements are now urgently required. While lung function parameters typically have been used as the primary endpoints in therapy development studies, the specific improvement in lung function in patients with CF (as a result of mucolytic therapy) has rendered these measurements less sensitive to potential effects of novel therapies. Therefore, the aim of this observational pilot study was to assess the precision and specificity of candidate intermediate endpoints of CF measured using hyperpolarized helium-3 (3He) magnetic resonance imaging (MRI). Accordingly we are assessing the measurement reproducibility of 3He MRI phenotypes in adults with CF and the relationship of MRI-derived CF lung phenotypes to established measurements of lung function.

2673. Ventilation and Heterogeneity in Mild-To-Moderate and Severe Asthmatics Using Hyperpolarized 3He MRI Yanping Sun1, Sanaz Zhalehdoust Sani2, Haihua Bao1, Yang-Sheng Tzeng1, Joey Mansour1, Jessica Gereige1, Xiangzhi Zhou1, Lindsey R. Madison1, Michael Hyosang Cho1, Elliot Israel1, Kenneth Lutchen2, Mitchell S. Albert1, 3 1Brigham and Women's Hospital, Boston, Massachusetts, USA; 2Boston University, Boston, Massachusetts, USA; 3University of Massachusetts Medical School, Worcester, Massachusetts, USA

Hyperpolarized 3He MRI was performed to investigate the ventilation heterogeneity response of mild-to-moderate and severe asthmatics, compared to healthy subjects at baseline, Methacholine(Mch) challenge, deep inspirations(DI), and Albuterol administration. Mch challenge produced a ventilation heterogeneity score change from baseline that was largest in the healthy subjects, smaller in the mild-to-moderate asthmatics, and least in the severe asthmatics. The healthy subjects and mild-to-moderate asthmatics showed a recovery of the heterogeneity score following DIs, suggesting a bronchodilation effect, while the severe asthmatics had impaired bronchodilation. Albuterol was shown to reverse the induced heterogeneity from Mch in both healthy subjects and asthmatics.

2674. A Method of Regional Assessment of Lung Structure and Function Using MDCT and Helium-3 MRI Eric T. Peterson1, Guillermo Gonzalez-Fernandez1, Sean B. Fain1 1University of Wisconsin - Madison, Madison, Wisconsin, USA

A high temporal resolution VIPR (3D PR) acquisition using hyperpolarized helium-3 was combined with a multi-step airway measurement algorithm combining airway segmentation, calculation of the centerline axis, lung airway measurement of diameter and branch angle. The high temporal resolution and high contrast of the acquisition allows for similar measurement of airways to the 3rd generation with values within 25% of those measured with multi-detector CT. Results approach the quality of commercially available CT airway segmentation packages for the large airways.

2675. Administration Unit for ³He Manuela Güldner1, Stefan Becker2, Andreas Friesenecker2, Klaus K. Gast3, Werner Heil1, Ernst Wilhelm Otten1, Alexander Scholz4, Wolfgang Schreiber3 1Institut für Physik, Mainz, Germany; 2ic-automation, Mainz, Germany; 3Klinik und Poliklinik für Radiologie, Mainz, Germany; 4Anästhesie, Mainz, Germany

An administration unit for hyperpolarized noble (HP) gases is presented which fulfills the safety requirements given by the Medical Devices Law. This device allows to administer gas boli (accuracy: ÄV / V < 3%) in a pre-defined time during the inspiration cycle. It enables to use gas mixtures and can be equipped with an on-line polarimeter to monitor the HP gas polarization.

Poster Sessions

438

2676. Effect of Reduced Pressure on the Polarization of 129Xe in the Production of Hyperpolarized 129Xe Gas: Development of a Simple Continuous Flow Mode Hyperpolarizing System Working at Pressures as Low as 0.15 Atm Hirohiko Imai1, Junko Fukutomi1, Atsuomi Kimura1, Hideaki Fujiwara1 1Osaka University, Suita, Japan

The effect of reduced pressure on the polarization of 129Xe has been examined in batch and continuous flow modes to produce hyperpolarized 129Xe in a simple way. The polarization of 129Xe was enhanced by reducing the total gas pressure down to near 0.1 atm in both modes, being enhanced to about twice of that observed near atmospheric pressure. Also, the stability of polarization in the continuous production of hyperpolarized 129Xe was sufficiently established in different flow rates. The technique developed in the present work is expected to provide a simple and handy type of 129Xe hyperpolarizing system.

2677. Impact of a Simulated Pulmonary Embolism in a Rabbit Model as Detected by XTC MRI Kai Ruppert1, 2, Jaime F. Mata2, Talissa Altes1, 2, Ugur Bozlar2, James R. Brookeman2, Klaus D. Hagspiel2, John P. Mugler III2 1The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA; 2University of Virginia, Charlottesville, Virginia , USA

Previous studies have demonstrated the feasibility of indirectly detecting a pulmonary embolism (PE) using hyperpolarized helium-3 MRI. In this work we investigated whether Xenon polarization Transfer Contrast (XTC) MRI can detect changes in pulmonary blood volume, and whether this method is sensitive enough to detect the impact of a simulated PE in a rabbit model. Our findings indicate that XTC MRI, despite being insensitive to perfusion, permits the observation of the regional redistribution of the pulmonary blood volume secondary to the PE.

2678. Detection of Interstitial Lung Disease in Humans with Hyperpolarized 129Xe Samuel Patz1, James P. Butler2, Iga Muradyan1, Mirko I. Hrovat3, Hiroto Hatabu1, Paul F. Dellaripa, Isabel M. Dregely4, Iulian Ruset4, F. William Hersman4 1Brigham and Women's Hospital, Boston, Massachusetts, USA; 2Harvard School of Public Health, Boston, Massachusetts, USA; 3Mirtech, Inc, Brockton, Massachusetts, USA; 4University of New Hampshire, Durham, New Hampshire, USA

Quantitation of the diffusion of hyperpolarized 129Xe from alveolar gas spaces to septal tissue allows one to measure functional pulmonary parameters. Here we demonstrate the ability to measure increased septal thickness in subjects with mild to moderate interstitial lung disease.

2679. High-Resolution Chemical Shift Imaging of the Lungs with Xe-129 During a Single 6 Second Breath-Hold: Results from a Rabbit Model of Pulmonary Embolism Jaime Mata1, Ugur Bolzar1, Kai Ruppert2, 3, Klaus Hagspiel1, Talissa Altes2, 3, Anthony Soltis1, Wilson Miller1, William Tobias1, Gordon Cates1, James Brookeman1, John Mugler III1 1University of Virginia, Charlottesville, USA; 2University of Pennsylvania, Philadelphia, USA; 3Children's Hospital of Philadelphia, USA

Previous implementations of Chemical Shift Imaging (CSI) of the lung with hyperpolarized xenon-129 (hpXe-129) required imaging for 8minutes, which is not practical for application in humans. We developed an optimized version of CSI that yields images of hpXe-129 with high in-plane spatial-resolution during a single breath-hold. We report the evaluation of this technique using a rabbit model of pulmonary embolism. From the CSI data we directly calculate images reflecting the amount of Xe-129 in the airspaces, and dissolved in the lung tissue and blood, and thus obtain spatial information regarding how Xe-129 is distributed in the different compartments, providing regional information about lung physiology.

2680. Detecting Simulated Pulmonary Embolism in a Rabbit Model with Hyperpolarized Xenon-129 Uptake Spectroscopy Yulin Chang1, Jaime F. Mata2, Ugur Bozlar2, Talissa Altes1, 2, James R. Brookeman2, Klaus D. Hagspiel2, John P. Mugler III2, Kai Ruppert1, 2 1The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA; 2University of Virginia, Charlottesville, Virginia , USA

Previous studies have demonstrated the feasibility of indirectly detecting a pulmonary embolism (PE) using hyperpolarized helium-3 MRI. In this work we investigated whether hyperpolarized Xenon-129 uptake spectroscopy can detect global changes in the xenon uptake dynamics for a simulated PE in a rabbit model. Although the uptake parameters in animals with and without PE differed considerably, the variability of the responses in the individual rabbits was also remarkably high and might indicate the impact of difficult to reproduce systemic responses.

2681. Simulations of the Hyperpolarized 129Xe SSFP and SPGR Pulse Sequence Signal Response Martin H. Deppe1, Jim M. Wild1 1University of Sheffield, Sheffield, UK

Imaging hyperpolarized (HP) 129Xe in the gas phase is the basis for promising techniques to assess lung function such as XTC, but suffers from an intrinsically lower SNR compared to HP 3He MRI owing to the lower gyromagnetic ratio. Typically, spoiled gradient echo (SPGR) sequences are used, but recently steady-state free precession (SSFP) sequences have attracted interest for imaging hyperpolarized agents, as the transverse magnetization can be recycled by balanced gradients, resulting in higher SNR. In this preliminary work we show computations for in vivo HP 129Xe MRI that suggest an SNR improvement by a factor of 3.2 by using an optimized SSFP sequence instead of a bandwidth matched optimized SPGR sequence.

Poster Sessions

439

Body Animal Studies Hall D Tuesday 13:30-15:30

2682. MRI of Awake Rats Jose Luis Ulloa1, Dave J. Barker1, Ann T. Doherty1, John C. Waterton1 1AstraZeneca, Alderley Park, Macclesfield, UK

The vast majority of MRI studies in rodents have employed anaesthesia for restraint. Despite the extensive experience, there remain some concerns in the use of anaesthesia and its consequences on the animal and on the metabolism of the substance under study. Neuromuscular blockers, sedatives, preparative anaesthesia and tightly restrained have been used as alternatives, but these approaches pose other problems. In this work we explore the feasibility to establish a protocol for MRI of the kidney in awake wrapped rats without pharmacologic support. Preliminary results in acclimatised animals indicate quantitative MRI of the kidney appears possible in awake wrapped rats.

2683. Non-Invasive Assessment of Inflammation in White Adipose Tissue Using Magnetic Resonance Imaging stephen C. Lenhard1, Alan R. Olzinski1, Roberta Bernard1, karpagam Aravindhan1, Amy Grill1, Beat Michael Jucker1 1GlaxoSmithKline, King of Prussia, Pennsylvania, USA

Obesity is associated with alteration in adipocyte metabolic/endocrine functions such as lipolysis, adipokine (i.e. leptin, adiponectin) and cytokine production (TNFa, IL-6). Adipocyte inflammation has taken a prominent role in mediating metabolic/endocrine alterations which result in insulin resistance and dyslipidemia. Ultrasmall Superparamagnetic Iron Oxide (USPIO) imaging contrast agents have previously been used as a surrogate for macrophage load and/or inflammatory activity. Therefore the aim of this study was to assess the feasibility of non-invasively imaging macrophage and/or activity as a surrogate for inflammation in various adipose tissue depots.

2684. Reliable Fat Suppression in Multiple-Mouse Imaging with a Dixon Technique Dustin K. Ragan1, James Andrew Bankson1 1M. D. Anderson Cancer Center, Houston, Texas, USA

Small animal MRI provides a diverse away of information to investigators, but imaging a large number of mice can be prohibitively time consuming and expensive. To alleviate this, techniques for the simultaneous imaging of multiple animals have been developed. However, shimming is more challenging with multiple volumes and chemical saturation techniques may become less reliable when used over multiple animals. We implemented a two-point RARE-based Dixon method for fat suppression on a Bruker 4.7T and demonstrated it in vivo with a custom-built four animal imaging system. Reconstruction was performed using the on-board phase correction algorithm.

2685. Non-Invasive Quantification of Hepatic Steatosis with 3.0 Tesla MR Spectroscopy in an Experimental Rat Model J. R. van Werven1, H. A. Marsman1, A. J. Nederveen1, F. J. ten Kate1, T. M. van Gulik1, J. Stoker1 1Academic Medical Center, Amsterdam, Netherlands

Hepatic steatosis is fat accumulation in the liver and liver biopsy remains the gold standard for assessment. 1H-MRS could be a non-invasive alternative. The purpose of this study was to quantify hepatic steatosis with 3.0 T 1H-MRS in a rat model and correlate these measurements with histopathological and biochemical analysis. Hepatic steatosis was induced by feeding rats a special diet.We found significant correlations between 1H-MRS measurements and histopathological macrovesicular steatosis and biochemical assessed fatty acids in the rat liver.3.0 Tesla 1H-MRS is able to measure hepatic fat and correlates with histopathological and biochemical analysis of hepatic fat.

2686. Cannabinoid-1 Inverse Agonist Treatment and Cessation Effects on Intrahepatocellular Lipid and Adipose Tissue Distribution in an Obesity Rodent Model Abdel Wahad Bidar1, Petter Ranefall1, Lillevi Kärrberg1, Pernilla Håkansson1, Maria Wigstrand1, Elisabeth Larsson1, Paul David Hockings1, Stephan Hjorth1 1AstraZeneca, Mölndal, Sweden

Cannabinoid-1 inverse agonist treatment results in food intake suppression and body weight loss. In this study, the aim was to describe in-vivo the changes in intrahepatocellular lipids, total, intra-abdominal and subcutaneous white adipose tissues and body weight during treatment with the CB1 antagonist rimonabant and following cessation of treatment in a mouse obesity model. Adipose tissue compartments were segmented using a fully 3D automatic procedure. Treatment with the CB1 antagonist reduced body weight and adiposity in our obesity mouse model. Interruption of treatment resulted in a marked increase in intrahepatocellular lipids and a regain in adiposity and body weight.

2687. The Effects of a High Fat Diet on Hepatic Lipid Levels and Sources in the Adult Rat Teresa Cardoso Delgado1, 2, Daniela Pinheiro3, Madalena Caldeira3, M.Margarida C.A. Castro1, Carlos F.G.C. Geraldes1, Pilar Lopez-Larrubia2, Sebastian Cérdan2, John Griffith Jones1 1FCT, Coimbra University; Center for Neurociences and Cell Biology, Coimbra, Portugal; 2Instituto de Investigaciones Biomedicas “Alberto Sols”, Madrid, Spain; 3FCT, Coimbra University, Coimbra, Portugal

High fat diet (HFD) is associated with the development of hepatic insulin resistance and promotes the accumulation of hepatic triglyceride content (HTGC) in humans, leading to liver steatosis. The hepatic triglycerides can derive directly from diet lipids or by de novo lipogenesis. This study aimed to determine if diet per se as an effect on rat HTGC and in vivo 1H MRS was used for evaluation of hepatic triglyceride accumulation. Simultaneously, we want to verify if these diet-induced changes on HTGC can have an effect on de novo lipogenesis rates.

Poster Sessions

440

2688. In Vivo 31P MRS Characterisation of ANIT-Induced Hepatobiliary Dysfunction Bhavana Shantilal Solanky1, Gina Sanchez-Canon1, Simon D. Taylor-Robinson1, Jimmy Bell1, Julie C. Holder2, I Jane Cox1, Po-Wah So1 1Hammersmith Hospital, Imperial College London, London, UK; 2GlaxoSmithKline Pharmaceuticals, Ware, UK

Hepatic 31P MRS was used to study biliary dysfunction in rats, induced by chronic ANIT feeding. Two groups of animals were fed a diet containing 0.1% and 0.05% ANIT for 14 days. An elevation in hepatic PDE levels after 2 weeks was found in the 0.1% group, indicating increased cell degeneration. Increased consumption of PME for cell membrane synthesis was suggested by the accompanying significant decrease in the PME level. However, this effect was not demonstrated in the 0.05% animals indicating the response to ANIT treatment is dose-dependent. This work supports the use of 31P MRS to study hepatobiliary disease.

2689. Age Dependent Elevation of Liver R2 in H-Ferritin Over Expressing Transgenic Mice Keren Ziv1, Batya Cohen1, Michal Neeman1 1Weizmann Institute of Science, Rehovot, Israel

Transgenic mice that over-express h-ferritin and EGFP in a tissue specific and inducible manner were used for evaluating the impact of liver h-ferritin over expression in aging mice on MR contrast and physiology of the liver. Prolonged over expression of h-ferritin in liver hepatocytes resulted in a significant elevation in R2 relaxation rates. Relaxation effects of ferritin were field dependent and were significantly enhanced at 9.4T relative to 4.7T. Histological analysis of transgenic and WT mice confirmed the increased iron content in the livers of aging h-ferritin over expressing transgenic mice.

2690. Cardiac-Specific Overexpression of GLUT1 Prevents the Development of Abnormal Ventricular Function in Diabetic Mice: An Investigation with MR Tagging and Spectroscopy Jia Zhong1, 2, Fang Bian1, Ming Lu1, Priyanjana Chaudhuri1, Suhanti Banerjee1, Rong Tian2, Xin Yu1 1Case Western Reserve University, Cleveland, USA; 2Brigham and Women’s Hospital, Boston, USA

Diabetes is associated with increased cardiac morbidity and mortality. Although there is currently no consensus as to the pathogenesis of diabetic cardiomyopathy, evidence is emerging that it may be related to derangements in myocardial energy metabolism. GLUT1 is a major transporter that mediates basal cardiac glucose uptake. It has been proposed that down regulation of GLUT1 expression partly contribute to myocardial dysfunction in diabetics. However, the functional significance of cardiac-specific GLUT1 overexpression in diabetic hearts remains undefined. In the current study, myocardial contractility was examined in STZ-treated widetype and GLUT1 overexpressed mice with MR tagging. Decreased cardiac functions were observed in wildetype diabetic mice with a shift in substrate utilization towards enhanced fatty acid oxidation. However, diabetes-associated ventricular dysfunction was absent in STZ-treated GLUT1 overexpressed mice showed with no alterations in fatty acid oxidation. Our results suggest that normalized/enhanced glucose transport can prevent functional deterioration in diabetic hearts.

2691. MRI Detection of Peritoneal Adhesion with Dialysate Enhancement Jerry S. Cheung1, 2, Hong Guo1, Joseph C. Leung1, Kar N. Lai1, Ed X. Wu1 1The University of Hong Kong, Pokfulam, Hong Kong

This study investigated the use of clinical peritoneal dialysis fluid (dialysate) as a peritoneal contrast agent to visualize peritoneal adhesions in rats at 7 Tesla. Intraperitoneal injection of dialysate (~0.1 mL/g) allowed the MR detection of peritoneal adhesions that were surgically induced in all rats studied (N = 6). MR measurements of adhesion surface areas correlated well with the postmortem estimations (R = 0.99). T1 and T2 values of undiluted dialysate were found to be 3017.5¡Ó35.3 ms and 108.4¡Ó2.0 ms, respectively. These findings demonstrated dialysate-enhanced MRI as a potentially valuable technique in clinical detection and evaluation of post-surgical peritoneal adhesion and to monitor therapeutic interventions (i.e., against peritoneal adhesion) in future preclinical research.

2692. Effect of Acute Hyperglycemia on Intra-Renal Oxygenation as Estimated by BOLD MRI in Rats Lu-Ping Li1, Joann Carbray1, Pottumarthi V. Prasad1 1Evanston Northwestern Healthcare, Evanston, Illinois, USA

Previous studies have documented increased renal medullary R2* values in rat kidneys as early as 2 days following initiation of diabetes. Here, we wanted to study the contribution (if any) of hyperglycemia directly to the observed increase in R2* values. Acute hyperglycemia was induced by intra venous administration of glucose. Our preliminary data do show small but significant increase in medullary R2* values post-glucose administration.

Fetal & Uterine Imagery Hall D Wednesday 13:30-15:30

2693. Foetal Cardiac Gating for MRI: A Wavelet Transform Based Approach for the Real-Time Detection of Foetal R-Waves Pierluigi Di Giovanni1, Alastair R. Allen1, Trevor S. Ahearn1, Thomas W. Redpath1 1Aberdeen University, Aberdeen, UK

A snapshot of the foetal cardiovascular system during its contraction phase provides useful information concerning the health of the foetus.The purpose of this work is to investigate the possibility of real-time detection of foetal R-waves; this would allow a foetal ECG gated MRI acquisition. The ECG obtained from a maternal abdomen is a combination of maternal and foetal QRS complex, a signal processing method is needed to extract the foetal R-waves. We implement a Wavelet based method to isolate the singularities of the signal associated with the high frequencies contained in the foetal R-waves.

Poster Sessions

441

2694. 3D Visualization of Organs in Chemically Fixed Human Embryos Acquired with Microscopic Spatial Resolutions Kazuki Ohya1, Yousuke Otake1, Shinya Handa1, Katsumi Kose1, Shigehito Yamada2, Kohei Shiota2 1University of Tsukuba, Tsukuba, Japan; 2Kyoto University, Kyoto, Japan

A mathod to visualize 3D structure of organs in chemically fixed human embryos acquired with microscopic spatial resolutions was developed. At first, a chemically fixed human embryo was imaged using a contrast-optimized T1 weighted 3D gradient echo sequence with a large matrix (256 x 256 x 512). Then an organ to be visualized was extracted using a region growing method and an interactive GUI tool. The extracted 3D region was visualized using a 3D visualization software package (Volume-One). The obtained result demonstrated a promise of our protocol.

2695. Exploring Alternative Contrast in the Uterus at High Magnetic Fields Angela Lynn Styczynski Snyder1, Timo Liimatainen1, Ute Goerke1, Michael Garwood1, Shalom Michaeli1 1Center for Magnectic Resonance Research, University of Minnesota, Minneapolis, Minnesota, USA

The contrast in the uterus was generated using a novel rotating frame relaxation method, Relaxations Along a Fictitious Field (RAFF). This rotating frame technique provided unique tissue contrast from the conventional free precession T1 and T2 methods. It is demonstrated that artifact-free RAFF maps could be reliably obtained at a 7 T field strength.

Body Fat & Obesity Hall D Thursday 13:30-15:30

2696. Variations in Basal Liver and Muscle Lipid Levels in Type II Diabetes Determined Using 1H MRS Mary C. Stephenson1, Emily Leverton1, Eric Y H Khoo1, Simon M. Poucher2, Carsten Liess2, Andrew J. Lockton2, Lars Johansson3, 4, Jan W. Eriksson3, 5, Peter Mansell1, Ian A. MacDonald1, Peter G. Morris1 1University of Nottingham, Nottingham, UK; 2AstraZeneca, Macclesfield, UK; 3AstraZeneca, Mölndal, Sweden; 4Uppsala University Hospital, Uppsala, Sweden; 5Sahlgrenska University Hospital, Gothenburg, Sweden

Evidence suggests that insulin resistance in type II diabetes is associated with excessive lipid levels in tissues such as the liver and skeletal muscle. Here we assess the reproducibility of basal lipid levels in the liver and total and intra myo-cellular lipid (IMCL) levels in the calf muscle in both type II diabetic and healthy subjects. Variation in these levels in both groups, measured over the period of a month, was larger than expected from that measured in a single session (up to 3-fold larger in the liver) thus indicating biological changes in baseline levels.

2697. Variations in Basal Liver and Muscle Glycogen in Type II Diabetes Determined Using 13C-MRS Emily Leverton1, Mary C. Stephenson1, Eric Y H Khoo1, Simon M. Poucher2, Carsten Liess2, Andrew J. Lockton3, Lars Johansson4, 5, Jan W. Eriksson4, 6, Peter Mansell1, Ian A. MacDonald1, Peter Gordon Morris1 1University of Nottingham, Nottingham, UK; 2AstraZeneca , Macclesfield, UK; 3AstraZeneca, Macclesfield, UK; 4AstraZeneca , Mölndal, Sweden; 5Uppsala University Hospital, Uppsala, Sweden; 6Sahlgrenska University Hospital, Gothenburg, Sweden

The reproducibility of measurement of glycogen concentration in liver and calf muscles in healthy and Type 2 diabetic subjects using 13C-MRS has been investigated. Variation in between successive scans on a single occasion was studied to find repeatability of the measurement and variation over timescales varying from 5 days to 4 weeks was studied to investigate biological variation. Biological variation occurred in both liver and calf muscle glycogen over a week in diabetic subjects. In the healthy group liver glycogen varied biologically over 2 weeks and calf glycogen did not change significantly at any time throughout the study.

2698. Non-Invasive Imaging of Differing Physical Forms of Dietary Fat During Digestion in Humans Caroline Louise Hoad1, Luca Marciani1, David Gray1, Ian Fisk1, Sakunkhun Makkhun1, Elisa Placidi1, Eleanor F. Cox1, John J. Totman1, Robin C. Spiller1, Penelope A. Gowland1 1University of Nottingham, Nottingham, UK

A 3D T1-weighted fat only excitation imaging sequence was used to determine the fate of four different sunflower oil meals in vivo in the gastro-intestinal (GI) tract. Four different volunteers were each serially scanned on a single occasion. A sunflower seed meal was visible as particulates on the fat only images in the stomach, and as increased signal intensity in the small bowel and ascending colon. Three different sunflower oil-in-water emulsion meals (one natural and two processed) all showed a different fat distribution in the stomach, with phase separation of one of the emulsions occurring soon after the meal was ingested.

2699. Short-Term Dietary Effects on Liver Lipids Measured with 3T MRS Susan Moyher Noworolski1, Kathleen Mulligan1, Michael Wen1, Laurie Herraiz1, Melissa Weinberg1, Grace A. Lee1, Jean-Marc Schwarz, 12 1UCSF, San Francisco, California , USA; 2Touro University, Vallejo, California , USA

Short-term effects on liver lipids were evaluated with 3T 1H MRS. Six subjects underwent seven days of a simple-sugar diet and seven days of an isocaloric, complex-carbohydrate diet as inpatients in a metabolic ward. A respiratory-motion corrected time series of 20cc single voxel spectra were acquired in the liver (TR/TE=2500/37ms). All subjects had higher liver lipids:water after the simple-sugar diet when compared to the complex-carbohydrate diet (median=136%, range=110-370%, p=0.031. This suggests that the simple-sugar diet may be associated with an increase in liver lipids which is detectable by 1H MRS after periods as short as seven days.

2700. Effect of 1H MRS Sequence on Absolute Quantification of Hepatic Lipid Gavin Hamilton1, Mike S. Middelton1, Mark Bydder1, Takeshi Yokoo1, Nicholas Cameron Pinto1, Joel E. Lavine1, Claude B. Sirlin1 1UCSD, San Diego, USA

We examine the effect sequence choice makes on the hepatic fat measured by 1H MRS. PRESS and STEAM spectra were collected from an animal fat phantom and in-vivo from the liver of 49 subjects. In the phantom, we found that the fat peaks showed non-exponential decay in the PRESS sequence. In vivo, we found that the PRESS sequence overestimated the lipid peak area with respect to STEAM, though this overestimate appeared systematic.

Poster Sessions

442

2701. Effect of a Physical Exercise Program on Intrahepatic and Visceral Lipids in Obese People - A Pilot Study Michael Ith1, Cecile Bachmann1, Philipp Scacchi1, Roland Kreis1, Nadine Messerli-Buergy1, 2, Monica Zehnder1, Katharina Meyer1, Emanuel R. Christ1, Kurt Laederach-Hofmann1, 3, Chris Boesch1 1University Bern, Bern, Switzerland; 2University College of London, London, UK; 3University Trier, Trier, Germany

Obesity, accumulation of visceral adipose tissue and increased intrahepatocellular lipids (IHCL) are linked, however the underlying pathophysiological mechanisms are not yet fully understood. Besides testing the methodology, this study aimed at the determination of these parameters prior and after a 3-month intervention of diet and exercise as well as on BMI and physical performance. The results show an increase in physical fitness in combination with a decrease of IHCL, BMI and visceral adipose tissue. The improvement in patients who were involved in physical exercise in combination with dietary counseling tended to respond better than those with dietary counseling only.

2702. High Resolution Measurement of Hepatic Fat Volume Fraction in a Single Breathhold Glen Morrell1, Paul Hopkins1, June Taylor1 1University of Utah, Salt Lake City, USA

High resolution multislice hepatic fat volume fraction measurement was performed in five obese volunteers using a three-point Dixon method, with all three echoes obtained during a single sequence repetition. The entire liver was imaged in about 13 seconds, easily within a single breathhold. Measured hepatic fat volume fraction correlated strongly with body mass index.

2703. Intrinsic Water-Suppression in TIDE-BSSFP Applied for Quantification and Differentiation of Adipose Tissue Gregor Sommer1, Ute Ludwig1, Tobias Baumann1, Dominik Paul1 1University Hospital Freiburg, Freiburg, Germany

MRI has the ability to determine the distribution of visceral and subcutaneous fat reliably without radiation exposure. The inherently bright fat-signal in bSSFP sequences (balanced Steady State Free Precession) in combination with frequency selective tissue suppression, such as FS-TIDE (fat suppressed-Transition into Driven Equilibrium), offers high potential in this context. This work introduces intrinsic water suppressed TIDE-imaging (WS-TIDE) in vivo and gives an estimate on its applicability as a tool for adipose tissue quantification in obese patients.

2704. Analysis of Composite Pulse Schemes for Abdominal Fat Suppression Andrew James Wheaton1, Mitsue Miyazaki, 12, Shinichi Kitane3 1Toshiba Medical Research Institute, Mayfield, Ohio, USA; 2Toshiba America Medical Systems, Tustin, California , USA; 3Toshiba Medical Engineering Co., Tochigi, Japan

Composite pulse spectral-saturation schemes are known to be more B1- and T1-robust than single pulse approaches. We investigated 2- and 3-pulse composite schemes as alternatives to STIR for fat saturation in 3D abdominal imaging. Numerical Bloch solutions were modeled for STIR, 2-pulse, and 3-pulse schemes for a range of δB1 and δT1. Model data were combined with experimental data to calculate the expected fat sat performance, time-efficiency, and SAR-efficiency of each technique. The 3-pulse scheme offered better B1-robustness and performance than 2-pulse or STIR, but marginal SAR- and time-efficiency. The 2-pulse scheme offered a good balance of performance and efficiency.

2705. Improvement of IDEAL Fat-Water Separation at Large FOV in the Presence of Gradient Non-Linearity and Severe Field Inhomogeneities Jong-Kai Hsiao1, 2, Hing-Chiu Chang2, Hon-Man Liu1 1National Taiwan University, Taipei, Taiwan; 2GE Healthcare Taiwan, Taipei, Taiwan

IDEAL produces robust fat and water separation by iteratively finding the optimal field map, which is compatible with multi-coil acquisition. The IDEAL method is, however, problematic in the presence of incorrect convergence of field map solutions. A 2-D linear field map estimation with region growing improves the IDEAL algorithm's immunity to field inhomogeneity. In this work, we propose another option using phase changing during different TEs to semi-automatically estimate field map in regions with severe field inhomogeneities. The proposed scheme is compatible with gradient nonlinear correction near the edge regions of the FOV, hence could improve the performance of IDEAL in larger FOV applications such as the abdomen.

2706. Effect of Inulin on Adipose Tissue Deposition and on Appetite Regulation Jelena Anastasovska1, Gina Julieth Sanchez Canon1, Po-Wah So1, Louise E. Thomas1, Amy H. Herlihy1, Jan Van Loo2, Neena Modi3, Jimmy D. Bell1, Gary Frost4 1Hammersmith Hospital, Imperial College London, London, UK; 2BENEO-Orafti Group, Tienen, Belgium; 3Chelsea & Westminster Hospital, Imperial College London, London, UK; 4University of Surrey, Guildford, UK

Effects of different diet constituents on obesity and related diseases are currently being investigated. Inulin is a natural plant ingredient with prebiotic properties. In this study, we investigate the effects of inulin on adiposity and appetite regulation. Using MRI and MRS we show that dietary intake of inulin significantly reduces the weight gain and adiposity as well as the intrahepatocellular lipid content in mice. In addition, we show that inulin can modulate total energy intake, possibly through changes in central appetite regulation, as assessed by MEMRI. Inulin appears to favourably modulate appetite regulation, hepatic lipid metabolism and adipose tissue content

Poster Sessions

443

Bowel Imaging Hall D Monday 14:00-16:00

2707. Rapid 3D T1-Mapping of Inflamed Bowel in Crohn’s Disease at 3.0 T Karin Horsthuis1, Aart J. Nederveen1, Marijn-Willem de Feiter1, Pieter CF Stokkers1, Cristina Lavini1, Jaap Stoker1 1Academic Medical Center, Amsterdam, Netherlands

The purpose of our study was to determine the feasibility and value of T1-mapping in abdominal MRI as an objective, quantifiable, and reproducible means of determining disease activity in luminal Crohn’s disease. For 9 patients we acquired T1-maps before and after administration of intravenous Gadolinium (Gd). Subsequently Gd-concentrations were calculated. We found a good correlation between Gd-concentration in inflamed bowel and CRP-values. Mean Gd -concentrations were higher in patients with moderate to severe disease than in patients with mild disease. It is feasible to perform T1-mapping of the abdomen and results are encouraging.

2708. Effect of a 5-HT3 Antagonist on Small Bowel Water Content Luca Marciani1, Steve Foley1, Caroline L. Hoad1, Eugene Campbell1, John J. Totman1, Eleanor F. Cox1, Alexander Armstrong1, Paul Manby1, Robin C. Spiller1, Penny A. Gowland1 1University of Nottingham, Nottingham, UK

Recent developments in MRI allow non-invasive, patient-acceptable monitoring of small bowel water content. In this placebo controlled, double-blind, randomised, 2-way cross-over study we aimed to assess the effect of a 5-HT3 antagonist (Ondansetron) on small bowel water content in healthy volunteers. 16 subjects were administered placebo or Ondansetron. We found that Ondansetron markedly increased fasting small bowel water content. This may reflect reduction in fasting small bowel migrating motor complex frequency. MRI has potential important clinical application in understanding the role of 5-HT3 antagonists in controlling small bowel water content and transit, and how these mediate gastrointestinal symptoms in IBS-D.

2709. Validating the Potential of 1H MRS in Assessing the Effects of Dietary Fatty Acids on the Modulation of Inflammation in an Animal Model of Inflammatory Bowel Disease (IBD) Sonal Varma1, 2, Ranjana Bird3, Michael Eskin2, Brion Dolenko1, Jayadev Raju3, Tedros Bezabeh1, 2 1National Research Council Institute for Biodiagnostics, Winnipeg, Canada; 2University of Manitoba, Winnipeg, Canada; 3University of Waterloo, Waterloo, Canada

1H MRS has been shown to be a sensitive tool for the study of colonic inflammation in inflammatory bowel disease (IBD). IBD can progress to colon cancer and this risk increases with the duration of disease. The effects of various dietary agents on colon cancer have been studied; however, knowledge of their effects on IBD and its sequential progression to cancer is very limited. Our study suggests that 1H MRS can accurately assess the effect of dietary fatty acids on inflammation in IBD and may be a suitable tool for chronological studies on IBD and its progression to colon cancer.

2710. In Vivo Detection of Early Colorectal Tumors in Mice Using Contrast-Enhanced Magnetic Resonance Imaging Devkumar Mustafi Mustafi1, Urszula Dougherty1, Marc Bissonnette1, Xiaobing Fan1, Marta Zamora1, Gregory S. Karczmar1 1The University of Chicago, Chicago, USA

A novel class of MRI contrast agents containing VO2+-chelated organic ligands has been developed that provide excellent T1 and T2* contrasts in high-resolution MR images of rodent tumors. We have demonstrated that these contrast agents are taken up by cancer cells which are highly glycolytic. These results provide the basis for in vivo MRI studies for early detection of colorectal tumors in mice. Results from in vivo MRI studies in a clinically relevant model demonstrate that small colorectal tumors of ~ 1 mm in size can be detected and MR images can be correlated with in vitro histological images.

2711. T2- And Perfusion-Based MRI Assessment of Colon Wall and Mesenteric Inflammation in the Rat Andreas Pohlmann1, Lorna Tilling1, Hervé Barjat1, Huw D. Lewis1, Kevin Lee1, Michael F. James1 1GlaxoSmithKline R&D Ltd, Harlow, UK

The TNBS rat model induces marked colon wall thickening and mesenteric inflammation reflecting human inflammatory bowel disease (IBD) and hence providing an opportunity to evaluate potential new treatments. We developed a methodology (T2w, contrast-enhanced T1w) for repeated MRI at 4.7T. Principal component analysis (PCA) applied to the T1w image time series highlighted colon wall and mesenteric inflammation, with the combined cross-sectional area increasing on average by 800% (TNBS-treated vs naïve). Actual T1 changes and gut motion artefacts were distinguished based on the normalized standard deviation. This technique showed a marked effect of a gold standard drug for IBD.

2712. Gadofluorine M Enhanced MR Imaging of Inflammatory Bowel Disease: Quantitative Analysis and Histologic Correlation in a Rat Model Bernd B. Frericks1, Jörg C. Hoffmann1, 2, Birgit Hotz1, Steffi Valdeig1, Bernd Misselwitz3, Karl-Jürgen Wolf1, Frank K. Wacker1, 4 1Charité, Campus Benjamin Franklin, Berlin, Germany; 2St. Marienkrankenhaus, Ludwigshafen, Germany; 3Bayer Schering Pharma, Berlin, Germany; 4Johns Hopkins Hospital, Baltimore, USA

Aim of the study was to analyze the enhancement-pattern of Gadofluorine M in the colonic wall of rats with inflammatory bowel disease (IBD), induced by transrectal DNBS application. T1w-SE-images at 2.4T were acquired before and immediately, and 5, 15, 45, 60, and 90 min after i.v.-application of Gadofluorine M. Signal intensities within the colon wall, S/N- and ER-ratios were obtained. Inflammation was assessed histologically. Based on the ER-ratios, the degree of IBD-inflammation was differentiable beginning at 60 min after contrast application. If reproducible in men, a determination of the inflammation’s degree could finally be achieved with a non-invasive imaging modality.

Poster Sessions

444

Whole Body Clinical Studies Hall D Tuesday 13:30-15:30

2713. Wide Short Bore MR at 1.5T: Reducing the Failure Rate in Severe Claustrophobics John I. Lane1, Christopher P. Wood1, Bradley D. Bolster, Jr. 2, Kevin J. Johnson2, Matt A. Bernstein1, Robert J. Witte1 1Mayo Clinic, Rochester, Minnesota, USA; 2Siemens Medical Solutions, Rochester, Minnesota, USA

Claustrophobic patients unable to complete a diagnostic MR scan of the head and/or spine on a standard 60cm bore MR scanner were attempted on a 70cm bore MR scanner before resorting to an anesthesia assisted scan. All but a small percentage were able to complete a diagnostic scan on the wide bore scanner and avoid anesthesia. The few failures at 70cm were limited to examinations involving the head, suggesting that in addition to substantially reducing the need for anesthesia-assisted MRI, use of the wide bore scanner could potentially eliminate the need for anesthesia altogether in spine-only examinations.

2714. Whole-Body T2* Mapping Cristina Rossi1, Andreas Boss1, 2, Michael Haap3, Petros Martirosian1, Claus D. Claussen2, Fritz Schick1 1Section of Experimental Radiology, Eberhard Karls University of Tuebingen, Tuebingen, Germany; 2Department of Diagnostic Radiology, Eberhard Karls University of Tuebingen, Tuebingen, Germany; 3Department of Endocrinology, Metabolism and Pathobiochemistry, Eberhard Karls University of Tubingen, Tuebingen, Germany

The study presents the feasibility of whole-body T2* mapping at 1.5 Tesla. Regional values of the T2* were computed in several body areas in healthy volunteers. The clinical applicability of the protocol was tested in one patient suffering from iron overload. Considerable differences in the T2* values computed in the patient were found in liver, spleen, kidney, and muscles as compared to the healthy volunteers. The presented technique may allow for a comprehensive estimation of the iron balance within the body in patients treated with repeated blood transfusions.

2715. Whole Body Diffusion Weighted MRI Compared to 18F-FDG Position Emission Tomography for the Detection and Localization of Malignant Lesions Hanane Antoun1, L Popa1, J A. Momo1, H Nasser2, F Admiraal-Behloul3, F Busy1 1Centre Hospitalier sud Francilien, Evry, France; 2Hopital Pive d'Antony, Antony, France; 3Toshiba Medical Systems, Zoetermeer, Netherlands

In this study was we investigated the potential usefulness of whole body diffusion weighted imaging (DWI) in the detection and localization of malignant tumors. For clinical evaluation, we compare this new technique to the well established Fluorine-18 Fluoro-deoxyglucose (18F-FDG) positron Emission tomography (PET)/ computed tomography (CT) in 20 patients with different pathologies.

2716. Preliminary Experience with Whole Body MRI @ 7T Stefan Maderwald1, 2, Oliver Kraff1, 2, Jens M. Theysohn1, 2, Andreas Bitz1, 2, Irina Brote1, 2, Karsten Wicklow3, Franz Schmitt3, Razvan Lazar3, Susanne C. Ladd1, 2, Harald H. Quick1, 2, Mark E. Ladd1, 2 1Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen, Germany; 2Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen, Germany; 3Siemens Medical Solutions, Erlangen, Germany

High-field MRI at 7-Tesla inherently offers high SNR and enhanced soft tissue contrasts when compared to 1.5T or even 3T MRI, which might improve image quality in selected imaging applications in humans. However, the reduced Larmor wavelength in tissue (ca. 12 cm), being shorter than the dimensions of the human body, renders non-neuro body imaging applications at 7T difficult. In this study the thoraco-abdominal region of four volunteers was imaged in a 34 cm inner-diameter CP transmit/receive coil on a 7T whole-body MRI system. Human liver, kidney, spine, and heart images were acquired with gradient and spin echo sequences.

Breast MR Hall D Wednesday 13:30-15:30

2717. Contrast-Enhanced MR Mammography: Improved Lesion Detection and Differentiation with Gadobenate Dimeglumine Compared to Gadopentetate Dimeglumine Federica Pediconi1, Antonella Roselli1, Valeria Dominelli1, Gianpaolo Pirovano2, Miles A. Kirchin3, Carlo Catalano1, Roberto Passariello1 1University of Rome “La Sapienza”, Rome, Italy; 2Bracco Diagnostics Inc., Princeton, New Jersey, USA; 3Bracco Imaging SpA, Milan, Italy

Gadobenate dimeglumine and gadopentetate dimeglumine were compared intra-individually in 47 patients referred for contrast-enhanced MR mammography (CE-MRM). The dose of contrast agent (0.1 mmol/kg bodyweight) was identical for the two examinations in each patient. Histopathology data were available for 50 malignant and 28 benign lesions. Significantly more lesions were detected after gadobenate dimeglumine (75/78 [96%] vs. 62/78 [79%]; p=0.0025) with specific benefits noted for the detection of malignant lesions (49/50 [98%] vs. 38/50 [76%]; p=0.0018). The characterization of histologically-confirmed lesions as malignant or benign on CE-MRM was significantly (p=0.0001) better after gadobenate dimeglumine.

2718. Role of Contrast-Enhanced MR Mammography (CE-MRM) in Women with Dense Breast Parenchyma: Comparison with X-Ray Mammography and Ultrasound Federica Pediconi1, Antonella Roselli1, Valeria Dominelli1, Miles A. Kirchin2, Carlo Catalano1, Roberto Passariello1 1University of Rome “La Sapienza”, Rome, Italy; 2Bracco Imaging SpA, Milan, Italy

A retrospective evaluation was performed of 238 women with dense breast parenchyma (BI-RADS 3 or 4) who were referred for contrast-enhanced MR Mammography (CE-MRM) after undergoing conventional bilateral x-ray mammography (n=133) and/or ultrasound (n=195). Overall, 89/238 women underwent all three techniques. The diagnostic performance of CE-MRM in terms of sensitivity, specificity, accuracy and positive and negative predictive values was greater on CE-MRM than on x-mammography and ultrasound.

Poster Sessions

445

2719. MR Imaging Features of Pre-Malignant and Pre-Invasive Breast Lesions: Can They Be Differentiated? Jeon-Hor Chen1, 2, Garima Agrawal1, Orhan Nalcioglu1, Min-Ying Su1 1University of California Irvine, Irvine, USA; 2China Medical University Hospital, Taichung, Taiwan

Contrast enhanced benign lesions are the major reasons contributing to the high false positive diagnosis by MRI. The MR morphological features and enhancement kinetics from 16 hyperplasic lesions and 34 DCIS were analyzed based on BI-RADS MRI Lexicon, and compared. There were no clear features that can differentiate between these two groups. The malignant type enhancement kinetics (wash-out or plateau) was seen in 46% hyperplasic lesions, whereas it was seen more frequently in 75% DCIS. DCIS was more likely to present clumped pattern; whereas the pre-malignant lesions were more likely to show punctuate pattern.

2720. Kinetic Assessment of Breast Lesions Using the Signal Enhancement Ratio from Rapid Radial DCE-MR Images Lawrence Dougherty1, Raymond C. Boston, Mark A. Rosen1, Linda White Nunes, Peter J. Moate, Hee Kwon Song1, Mitchell D. Schnall1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA

The diagnostic performance was evaluated for DCE-MR breast imaging using the signal enhancement ratio (SER) to assess kinetic response. SER is the ratio of the signal at 60s post-contrast injection to the signal at 350s post injection (intensities relative to pre-contrast signal intensity). Images were acquired using an undersampled radial sequence. Sixty-four (64) enhancing lesions were evaluated using SER. ROIs were placed by two readers and the signal intensity plots were fitted and SER calculated. Using SER<0.8 for a benign classification, the combined readers’ performance was: Sensitivity = 92%, Specificity = 95%, PPV=93%, NPV=93% and the diagnostic accuracy was 93%.

2721. Kinetic Parameter Estimation Based on Independent Component Analysis of Breast Dynamic Contrast-Enhanced MRI Yi Wang1, Bao Zhang2, Steven Roys2, Rao Gullapalli2 1University of Utah, Salt Lake City, Utah, USA; 2University of Maryland, School of Medicine, Baltimore, Maryland, USA

We extent our recent success with the application of independent component analysis (ICA) in the detection of breast cancer to kinetic parameter estimation on spatial components obtained from such analysis. Twenty breast cancer patients¡¯ data were subject to ICA followed by kinetic parameter estimation of the raw data based on the independent components derived from ICA. Kinetic parameters derived from these spatial components were compared with those obtained from radiologist¡¯s assessment of the tumor using an existing CAD system. The sensitivity and specificity of the combined ICA and kinetic parameter estimation was 80 and 100% respectively compared to the radiologist.

2722. Developing Markers for Stratifying Patients Into Good vs. Poor Prognostic Categories Using Pre-Neoadjuvant Chemotherapy Three Time Points Breast Contrast-Enhanced MRI and Histogram Analysis Ka-Loh Li1, Jessica Gibbs1, Evelyn Proctor1, Savannah C. Partridge2, Xiaoping Zhu1, Laura Esserman1, Nola M. Hylton1 1University of California, San Francisco, San Francisco, USA; 2University of Washington, Seattle, Washington, USA

Early prediction of failure is essential in treatment planning for breast cancer patients. We studied 31 consecutive women who had primary invasive ductal carcinoma and preoperatively underwent four cycles of chemotherapy. Patients were divided into 'recurrence-free' (n=18) and 'recurrence' (n=13) groups based on follow-up information. Predictors were developed based on histogram analysis of data from pre-chemotherapeutic three time points contrast-enhanced MRI. A combined use of the predictors has identified 5/13 recurrence and 15/18 recurrence-free patients: None of the recurrence-free patients was misidentified as likely to recur, and none of the recur-patients was misidentified as unlikely to recur.

2723. Silicone-Specific Imaging Using a Single-Echo Dixon Technique Jingfei Ma1 1University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA

Previous methods on using the multiple-point Dixon techniques for silicone-specific imaging have to either assume that the frequency separation between W and S is twice the frequency separation between F and S, or to rely on using a preparatory inversion pulse to suppress F, or to require additional data acquisition and extensive processing to directly decompose the three components. In this work, we report that by acquiring a single-echo gradient echo image with the echo time set for water and fat in-phase, a single-echo Dixon algorithm with a flexible echo time can be used to generate excellent silicone specific images both in phantom and in vivo.

2724. Faster Magnetic Resonance Imaging of Breast Implants Using the IDEAL Technique Anna-Marie O'Connell1, Charles A. McKenzie2, Ananth Madhuranthakam1, Ivan Pedrosa1, Vandana Dialani1, Neil M. Rofsky1 1Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA; 2University of Western Ontario, London,, Canada

This study evaluates breast implant assessment with Short Tau Inversion Recovery (STIR) sequence modified to allow generation of water-only and silicone-only images with the IDEAL (Iterative-Decomposition of water and fat with Echo Asymmetry and Least-squares estimation) reconstruction technique. STIR techniques in isolation employ chemically selective suppression pulses and are known to be sensitive to magnetic field inhomogeneities. Seventeen women with implants were therefore imaged using the IDEAL-STIR combined technique. All 17 studies were diagnostic. The IDEAL technique took 15 minutes while the standard technique takes more than 35. IDEAL successfully produced fat suppressed water-only and silicone-only images in all 17 cases. No studies needed to be repeated. We conclude that MRI of breast implants using the IDEAL-STIR technique is significantly faster and more reliable than traditional assessment techniques.

Poster Sessions

446

2725. Quantitative Evaluation of an Elastic 3D Motion Correction Applied to High Resolution Breast MRI Christian Geppert1, Evelyn Wenkel2, Gerardo Hermosillo-Valadez3, Werner Bautz2, Berthold Kiefer1, Rolf Janka2 1Siemens Medical Solutions, Erlangen, Germany; 2Radiologisches Institut, Erlangen, Germany; 3Siemens Medical Solutions, Malvern, Pennsylvania, USA

Motion artefacts can occur in MR breast imaging even with very cooperative patients and highest care in patient positioning, for example due to progressive relaxation of the pectoral muscles. In this work, the performance of a 3D elastic motion correction to high resolution breast MR data is described. Motion artefacts were measured as apparent skin thickening artefact as well as pectoral muscle subtraction artefact. The mean values of the skin motion artefact were originally 2.7mm (std deviation 1.1mm) and 0.7(0.89) mm after performing the correction. The averaged values for the muscle motion artefact was 4.8(2.95) mm before and 2.04(2.18) mm after the correction. Overall, a complete correction i.e. no remaining measureable artefact was achieved in 23 out of 47 times for skin motion respective 23 out of 48 times for muscle motion artefact.

2726. Reduced B1-Inhomogeneities in Breast MRI Using Optimized RF Excitation Christian Geppert1, Juergen Nistler1, Wolfgang Renz1, Ioannis Panagiotelis1, Thorsten Speckner1 1Siemens Medical Solutions`, Erlangen, Germany

B1-inhomogeneities are well known to occur at high field strengths. Only recently this issue has been raised for breast imaging at 3.0T: apart from the basic problem of image homogeneity, severe concern was expressed regarding possible misinterpretations of contrast uptake if the actual excitation angle deviates too strong from the nominal FLASH angle in gradient echo sequences used for dynamic studies. In this work, a novel method to improve the homogeneity that uses optimizations for the feeding of the body coil was tested and compared on volunteers. While different approaches to reduce B1-shading have been suggested previously, such as parallel transmission or the use of B1 saturation pads, this method provides a cost-effective solution using the standard transmit setup of a clinical 3T scanner.

2727. Parallel Imaging of Supine Breast for Recovery of Motion-Corrupted Data Helen Marshall1, Peter Siegler1, Patrick Micheal Devine1, Donald Bruce Plewes1 1Sunnybrook Health Sciences Centre, Toronto, Canada

Supine breast imaging alleviates the problem of registering images acquired in a prone position to the supine orientation inherent to breast surgery. Parallel imaging was implemented for supine breast imaging with a gating and k-space reordering technique to compensate for respiratory motion, and used to recover data corrupted by additional non-respiratory motion. The proposed method protects data acquisition from motion events by grouping the even and odd phase encoding steps in time. Parallel imaging allows useable images to be reconstructed from a motion-corrupted dataset, providing that one of the data subsets (even or odd) remains viable.

2728. Dynamic Contrast-Enhanced Breast MRI Using Dual-Resolution 3D Spiral Imaging Brian A. Hargreaves1, Bruce L. Daniel1 1Stanford University, Stanford, California , USA

Dynamic contrast-enhanced (DCE) imaging a standard technique for breast MRI, but is limited by both spatial and temporal resolution. Spiral image acquisition is fast and efficient, and can be designed to cover k-space with different densities for low and high spatial frequency information. This allows simultaneous acquisition of low and high spatial resolution images with fast and slower frame rates. We have demonstrated that this combination provides a useful tradeoff for DCE imaging in breast cancer patients, providing low and high resolution 3D images every 12 and 60 seconds.

2729. Accelerated Bilateral DCE 3D Spiral Breast Imaging: Comparison Between TSENSE and TGRAPPA Misung Han1, 2, Bruce L. Daniel1, Brian A. Hargreaves1 1Stanford University, Stanford, California , USA

Using a dual-band excitation and 3D spiral imaging, both breast volumes can be efficiently imaged. Acquisition time can be reduced using TSENSE or TGRAPPA, where odd and even phase encode planes are acquired sequentially. Full images are used for calibration, and parallel imaging can then reconstruct accelerated frames. We compared the combination of 3D spiral imaging with TSENSE and TGRAPPA in bilateral DCE breast imaging. Both methods provided diagnostic breast images with 10 second temporal resolution, but TGRAPPA yield less oscillation in the signal intensity curves in tumors due to reduced residual aliasing.

2730. Slab-Phase Modulation Combined with Parallel Imaging in Bilateral Breast Imaging Misung Han1, 2, Brian A. Hargreaves1 1Stanford University, Stanford, California , USA

By incorporating phase modulation with a dual-band spectral-spatial pulse, two breast volumes can be imaged simultaneously without the need to phase encode the unexcited space between the two volumes. In this work, we have combined self-calibrated parallel imaging using mSENSE and GRAPPA in the slice direction to the separately excited breast volumes, comparing results with and without slab-phase modulation. Our results show slab-phase modulation improves reconstructed image quality in terms of artifacts and SNR in both mSENSE and GRAPPA reconstructions.

2731. Rapid B0 Shimming with Three Orthogonal Frequency Maps Timo Liimatainen1, Patrick J. Bolan1 1University of Minnesota, Minneapolis, Minnesota, USA

A fast image-based shimming method based on phase difference measurement from three orthogonal slices was introduced. This new technique requires only 7 s measurement time for estimation of 1st and 2nd order shim currents. Reliable shim current estimation was achieved also in the presence of discontinuities of frequency and chemical shift (water and fat interface). The results suggest reliable performance of new method in conventionally challenging tissue, such like breast, and will be particularly valuable for shimming in the body where physiological motion reduces conventional shimming performance.

Poster Sessions

447

2732. High-Resolution 3D Bilateral Breast Imaging Using Slice Direction Autocalibrated Parallel Imaging Marcus T. Alley1, Brian A. Hargreaves1, Bruce L. Daniel1, Philip J. Beatty2, Anja C. Brau2 1Stanford University, Stanford, California , USA; 2GE Healthcare Technologies, Menlo Park, California , USA

For patients needing a Dynamic Contrast-Enhanced (DCE) MR breast exam, bilateral breast imaging is playing an increasingly important clinical role. Our DCE protocol includes a high-resolution 3D acquisition to provide anatomic data for use in diagnosis. Here we present results from a modified version of this acquisition that performs a slice-accelerated bilateral breast study using an autocalibrated parallel imaging technique in a scan time comparable to an equivalent unilateral study. Excellent image quality is obtained in both the native sagittal and reformatted axial planes, with the latter demonstrating the lack of residual aliasing artifacts in the slice direction.

2733. Rapid Parallel Breast MRI with a Custom Coil Array Glen Morrell1, Rock Hadley1, Emilee Minalga1, Eugene Kholmovski1, Matthias Schabel1 1University of Utah, Salt Lake City, USA

A prototype breast coil was constructed to allow large reduction factors for parallel breast imaging. The coil consists of four plates, each with eight rectangular coil elements stacked in the z direction in a ladder configuration. Sample images are shown with a reduction factor of 4 for an 8 element subset of the complete coil set. Increased imaging speed made possible by parallel imaging will increase the accuracy of parametric perfusion modeling and allow high resolution depiction of morphology, which has the potential to significantly increase the specificity of breast MRI.

2734. Enhanced Lesion Discrimination in Breast DWI After Contrast Administration Christian Geppert1, Evelyn Wenkel2, Werner Bautz2, Berthold Kiefer1, Rolf Janka2 1Siemens Medical Solutions, Erlangen, Germany; 2Radiologisches Institut, Erlangen, Germany

Numerous recent publications describe the use of diffusion-weighted imaging (DWI) for the detection, assessment or treatment response monitoring of breast cancer. While there appears to be good agreement that the additional evaluation of the apparent diffusion coefficient (ADC) can significantly increase the specificity of breast MRI, the applied pulse sequences, b-values and approach (before or after contrast administration, selected slices or complete volumes) differ. In this work, the effect of T1-shortening contrast administration (CA) on the ADC values of fat saturated DW-EPI and its impact on the ability to differentiate benign from malignant breast lesions is investigated. The ADC values of benign lesions were 1.8 (on average, values ranged from 1.4 to 2.6) 10-3 mm2/s before and 1.9(1.5; 2.5) 10-3 mm2/s after contrast administration. Malignant lesions exhibited a mean ADC of 1.0(0.6; 1.2) 10-3 mm2/s prior to and 0.9(0.5; 1.2) 10-3 mm2/s after CA.While there is no significant change for benign lesions the ADC decrease in post-contrast malignant lesions is significant (p<0.05) which in principle would lead to an improved lesion discrimination.

2735. Clinical Application of Diffusion-Weighted Imaging with ASSET Technique for Breast Lesions JIN Guangwei1, An Ningyu, Zeng Qingyu2 1Meitan General Hospital, Beijing, People's Republic of China; 2Meitan General Hospital, People's Republic of China

DWI provides unique information about the state of molecular translational motion of water and maily detectes random, thermal motion of hydrone in vivo. The conventional DWI£¨SS-EPI£©used in breast can develope distortion of image. In this study, we investigated the tehnical feasibility of DWI with ASSET (array spatial sensitivity encoding technique) for patients with breast diseases, to study if ASSET-DWI can decrease the distortion with shorter acquisition time and to evaluate the diagnosis value of ASSET-DWI in distinguishing benign and malignant breast lesions. The results indicated ASSET-DWI can be used for breast with decrease of distortion and acquisition time. Either b value being 600s/mm2 or 1000s/mm2£ADC value of ASSET-DWI all can be used to distinguish majority of malignant lesions from benign ones. The diagnostic threshold of ADC value should be matched with the b value used in ASSET-DWI simultaneouly.

2736. Prognostic Imaging in Neoadjuvant Chemotherapy Should Be Cost Effective Brian William Pogue1, Anna N. A. Tosteson2, Marc Schegerin1, Peter A. Kaufman2, Keith D. Paulsen1 1Dartmouth College, Hanover, New Hampshire, USA; 2Dartmouth Medical School, Lebanon, New Hampshire, USA

Cost effectiveness modeling was used to analyze if imaging in the course of neoadjuvant chemotherapy for breast cancer treatment should be carried out. The analysis showed that specificity of the imaging test was a secondary factor in knowing if this should be done, and that the primary factor in assessing this was the success of a secondary treatment strategy. The prognostic success of imaging during therapy will allow testing of possible secondary therapies in a clinical trial.

2737. Are Kinetic Parameters Related to Prognostic Indicators in < 2.0 Cm Invasive Ductal Carcinomas? Sanaz Arkani Jansen1, Gregory Karczmar, Akiko Shimauchi, Hiroyuki Abe, Gillian Newstead 1University of Chicago, Chicago, Illinois, USA

We separate the effect of lesion size from the assessment of the relationship between MR kinetic parameters and prognostic indicators by evaluating the kinetic characteristics of 71 small T1 (< 2.0 cm) invasive ductal carcinoma (IDC) lesions. The kinetic parameters were classified by estrogen receptor (ER) status, nuclear grade and node invasion. We found that compared with ER positive and grade I and II lesions, ER negative and grade III tumors showed stronger washout. These results suggest that kinetic parameters are related to certain prognostic indicators irrespective of lesion size.

2738. Simple Classification of Contrast Enhancement Curves in DCE MRI Correlates to Breast Cancer Survival Pål Erik Goa1, 2, Mariann Gjervik Heldahl2, Roar Johansen2, Jana Rydland1, Kjell Arne Kvistad1, Steinar Lundgren1, 2, Ingrid Susann Gribbestad2 1St.Olavs University Hospital, Trondheim, Norway; 2Norwegian University of Science and Technology (NTNU), Trondheim, Norway

Dynamic contrast-enhanced (DCE) MRI derived parameters correlate to tumor characteristics and treatment response in breast cancer patients. A method for voxel-by-voxel classification of tumor tissue according to the shape of the contrast enhancement curve was implemented, and a color coded overlay illustrating spatial distribution of the different curve types was produced to improve visual inspection of the DCE-MRI data. The volume of tissue classified as having the fastest uptake/washout showed correlation to clinical outcome after 5 years.

Poster Sessions

448

2739. Predicting 5 Years Survival for Breast Cancer Patients Using Dynamic Contrast Enhanced MRI Line Rørstad Jensen1, Roar Johansen1, Pål Erik Goa1, 2, Jana Rydland2, Kjell Arne Kvistad2, Tone Frost Bathen1, Steinar Lundgren, 12, Ingrid S. Gribbestad1 1Norwegian University of Science and Technology, Trondheim, Norway; 2St. Olav’s University Hospital, Trondheim, Norway

Some of the patients with locally advanced breast cancer fail to respond to neoadjuvant chemotherapy (NAC). Previous studies of dynamic contrast enhanced MRI (DCE-MRI) have shown that correlates to treatment response. The aim of this study was to investigate the feasibility of DCE-MRI in prediction of 5 years survival in breast cancer patients undergoing NAC. The results demonstrate significantly lower values for the DCE-MRI derived parameter RSI in survivors compared to non-survivors.

2740. DCE-MRI Assessment of Neoadjuvant Chemotherapy and Clinical Outcome in Locally Advanced Breast Cancer Patients Mariann Gjervik Heldahl1, Tone Frost Bathen1, Line Rørstad Jensen1, Pål Erik Goa1, 2, Steinar Lundgren1, 2, Ingrid Susann Gribbestad1 1NTNU, Trondheim, Norway; 2St. Olavs University Hospital, Trondheim, Norway

Dynamic contrast enhanced MRI (DCE-MRI) derived parameters can be correlated to effect of breast cancer treatment. In a study of locally advanced breast cancer patients (n=67) receiving neoadjuvant chemotherapy, the DCE-MRI results were analysed for predictive and prognostic information. Mean relative signal intensity (RSI) and area-under-curve (AUC) values showed a significant decrease during NAC in clinical defined responders but not for non-responders. The difference was even more pronounced using DCE-MRI determined response. Based on the RSI-distributions, patients with a skew value higher than the mean skew survived longer than patients with a lower skew value (p=0,031).

2741. Predicting Nodal Status Using MRI-Based Clinical Response and Pathological Response of the Primary Tumor in Patients with Locally Advanced Breast Cancer Undergoing Neoadjuvant Chemotherapy Min-Ying Su1, Kelly Huynh1, David J.B. Hsiang1, John A. Butler1, Rita S Mehta1, Shadfar Bahri1, Jeon-Hor Chen1, 2, Orhan Nalcioglu1 1University of California Irvine, Irvine, USA; 2China Medical University Hospital, Taichung, Taiwan

The predicting accuracy of nodal status in patients after NAC based on MRI-based response and final pathological response was investigated in 48 patients. Her2 negative patients had a lower pCR rate than Her2 positive patients (36% vs. 78%), also had a higher rate with positive nodes (48% vs. 9%). The accuracy of the DCE-MRI results in predicting nodal status was 64% in Her2 – groups; and 87% in Her2 + groups. The prediction based on pathological response of primary tumor was only comparable to that of MRI response. DCE-MRI response had 100% NPV for predicting negative nodes for Her2 + patients, thus they may be spared of axillary node dissection.

2742. MR Imaging in Predicting Pathological Response of Inflammatory Breast Cancer and Non-Inflammatory Breast Cancer with Skin Involvement Following Neoadjuvant Chemotherapy Jeon-Hor Chen1, 2, Rita S Mehta1, Shadfar Bahri1, Orhan Nalcioglu1, Min-Ying Su1 1University of California Irvine, Irvine, USA; 2China Medical University Hospital, Taichung 40407, Taiwan

The MR imaging features and pathological response of 25 inflammatory breast cancers and 12 non-inflammatory breast cancers with skin enhancements on MRI were reported. IBC showed more aggressive disease presentations, with bigger tumor size and a high percentage of non-mass type lesions. Their response to our current neoadjuvant chemotherapy protocol combining AC and taxane-based regimens was similar with 50% patients achieved pathological complete response (pCR) in both groups. The accuracy of MRI in predicting pCR also did not show significant difference (11/16 in IBC vs. 5/6 in non-IBC); with a higher false negative in IBC (5/24) compared to non-IBC (1/12).

2743. Impact of MRI-Evaluated Neoadjuvant Chemotherapy Response on Change of Surgical Recommendation in Breast Cancer Byron Feig1, Jeon-Hor Chen1, 2, David J.B. Hsiang1, John A. Butler1, Rita S Mehta1, Shadfar Bahri1, Orhan Nalcioglu1, Min-Ying Su1 1University of California Irvine, Irvine, USA; 2China Medical University Hospital, Taichung, Taiwan

We investigated how the MRI-evaluated NAC response affected surgeon’s recommendation for choosing the optimal surgery in 76 patients. Before NAC, consensus recommendation of mastectomy was made for 49 patients, lumpectomy for 23 patients. After NAC, 22 mastectomy candidates remained as mastectomy, with pre-treatment size of 5.6 ± 3.2 cm. Twenty mastectomy candidates were changed to lumpectomy, and they had a smaller pre-treatment size 3.6 ± 1.9 cm. The results indicated that in patients who had more extensive pre-treatment disease, despite of their great response to NAC, the surgeons may still apply an aggressive approach and recommend for mastectomy.

2744. Are Kinetic Parameters Diagnostically Useful for Breast Lesions Exhibiting Nonmass-Like Enhancement? Sanaz Arkani Jansen1, Xiaobing Fan, Gregory Karczmar, Maryellen Giger, Hiroyuki Abe, Gillian Newstead 1University of Chicago, Chicago, Illinois, USA

The purpose of this study was to investigate whether the sensitivity and specificity of kinetic parameters can be improved by considering mass and nonmass breast lesions separately. The contrast media uptake and washout kinetics of 112 breast lesions (34 benign, 78 malignant) were analyzed using an empirical mathematical model. Our results suggest that kinetic analysis is not effective for nonmass lesions, while may be quite effective in mass lesions. The diagnostic utility of kinetic analysis of breast lesions, for example in computer aided diagnosis schemes, is likely improved if performed after identifying the lesion as mass-like or nonmass-like enhancement.

2745. MR Imaging Features of Triple Negative Breast Cancer Jeon-Hor Chen1, 2, Hyeon-Man Baek1, Rita S Mehta1, Philip Carpenter1, Orhan Nalcioglu1, Min-Ying Su1 1University of California Irvine, Irvine, USA; 2China Medical University Hospital, Taichung, Taiwan

The MR imaging features of 29 TN (triple-negative, ER, PR and HER2 negative) tumors were reported, 25 with pure invasive ductal cancer (IDC), and 4 metaplastic (IDC with squamous or chondroid components). 23/29 lesions were greater than 2 cm, indicating the late diagnosis. The imaging features were consistent with that of IDC; 28/29 were mass lesions. The enhancement kinetics was measured from 22 lesions, and all showed the malignant pattern with wash-out in late phase. Approximately half (14/29) showed enlarged lymph nodes in the axilla. Nine of these patients had MR spectroscopy study, and 7 showing elevated choline.

Poster Sessions

449

2746. PET/CT Versus MRI for Detection of Bone Metastases in Patients with Breast Cancer Johan Grankvist1, Rune Vincents Fisker1, Victor Vishwanath Iyer1, Finn Taagehøj Jensen1, Ernst-Torben Wilhelm Fründ1, Carsten Wiberg Simonsen1, Thorkil Christensen1, Marianne Ewertz Kvistgaard1, Elna-Marie Larsson1 1Aalborg Hospital / Aarhus University Hospital, Aalborg, Denmark

The project compares MRI with 18-DFG-PET/CT. Breast cancer patients with suspected or known bone metastases, are examined on both modalities. For 27 predefined locations in the spine and pelvic bones, 2 independent groups of doctors assign metastases detected on each modality. The results from both groups were compared for the first 9 patients. 44 metastases were detected on PET/CT. All 44 metastases were found on MRI. In addition 34 lesions were detected on MRI only, probably representing post therapeutic residuals without active tumour.

2747. Frequency Selective Inversion of Lipid Improves Choline Conspicuity in Breast Spectra Martin Lowry1, Ralph Noeske2, Martin D. Pickles1, Lindsay W. Turnbull1 1University of Hull, Hull, UK; 2GE Healthcare, Berlin, Germany

The presence of an elevated choline peak in proton spectra appears to be consistent marker of malignancy in many tissues. In most tissues this is relatively easy to detect. In breast tissue, however, the dominant peaks from lipid may considerably reduce the visibility of choline. Several approaches have been used to combat this problem. The method which has gained some acceptance combines T2-weighting and TE-averaging using long echo-times (~150ms) to reduce lipid signal and also removing sideband artefacts. In this study we implemented an additional fat suppression pulse that allows shorter echo times and used enhanced post-processing for frequency referencing.

2748. A Robust Automated Shimming Procedure for Breast MR Spectroscopy Evelyne Balteau1, 2, Geoffrey David Charles-Edwards3 1University of Liege, LIEGE, Belgium; 2University College London, LONDON, UK; 3Guy's & St Thomas' NHS Foundation Trust, LONDON, UK

MR spectroscopy offers attractive possibilities for the non invasive in vivo assessment of breast lesion biochemistry, as an aid for diagnosis and an early indicator of disease response to treatment. Effective shimming to achieve a high magnetic field homogeneity is paramount for MRS to achieve sufficient spectral resolution and avoid positional errors. However, few studies aiming breast spectroscopy address this often challenging issue. In this study, an automated shimming procedure is implemented and adapted for optimal breast MRS on a 1.5T clinical scanner. The robustness of the technique is demonstrated by both in vitro and in vivo experiments.

2749. Choline Profiles of Breast Cancer Correlate to Clinical Tumor Characteristics Beathe Sitter1, Tone Frost Bathen1, Maria Tunset Grinde1, Hans Fjøsne2, Jostein Halgunset1, Steinar Lundgren2, Ingrid S. Gribbestad1 1NTNU, Trondheim, Norway; 2St. Olav University Hospital, Trondheim, Norway

Choline profiles were obtained from 336 tissue biopsies from breast cancer patients using HR MAS MR spectroscopy. Peak ratios and partial least square regression were used to compare choline profiles to clinical parameters related to tumor characteristics. Significant differences were found for choline peak ratios of ER hormone positive and negative tumors, and for non-involved tissue compared to IDCs. ER status predicted from the choline profiles was significantly correlated to clinically predicted ER status using PLS. The choline profiles displayed a high level of variance, reflecting the complexity of breast tumor biology.

2750. Three Dimensional Spectroscopic Imaging in Breast Cancer at 3Tesla: A Pilot Study Stephan Gruber1, Katja Pinker2, Wolfgang Bogner1, Günther Grabner2, Andreas Stadlbauer3, Thomas Helbich2, Siegfried Trattnig2 1Medical University of Vienna, Vienna, Austria; 2Medical University of Vienna, Austria; 3Landesklinikum St. Poelten, Austria

In this study we tested 3D-MR-spectroscopic imaging in breast cancer. Compared to previous studies, performed with single voxel spectroscopy or 2D-MR-spectroscopic imaging, we could cover a larger fraction of the breast. In all patients with biopsy confirmed cancer, Cho was detectable in more than one slice, pointing out the importance of 3D-MRSI for diagnosis of breast cancer. Cho with a relative high SNR may be detected in voxels containing benign tissue, too. Therefore, specificity of this method should be tested in further studies.

2751. Validation of a Novel Spectroscopic Diffuse Optical Tomography System for Breast Imaging with MRI Stephanie M.W.Y. van de Ven1, Sjoerd G. Elias1, Andrea J. Wiethoff2, Marjolein van der Voort3, Anais Leproux3, Tim Nielsen4, Bernhard Brendel4, Leon Bakker3, Martin B. van der Mark3, Willem P.Th.M. Mali1, Peter Luijten1 1University Medical Center Utrecht, Utrecht, Netherlands; 2Philips Medical Systems, Best, Netherlands; 3Philips Research Europe, Eindhoven, Netherlands; 4Philips Research Europe, Hamburg, Germany

Diffuse Optical Tomography (DOT) uses near-infrared light to assess the three-dimensional distribution of optical properties of tissue. By combining data acquired at multiple wavelengths (spectroscopy), tissue composition in terms of concentrations of oxy- and deoxyhemoglobin, water and lipid can be determined. In this study, DOT measurements in 24 cystic breast lesions were validated with MRI. Optical images showed excellent spatial agreement with MRI. Spectroscopic analysis of the lesions elucidated their high water content and low total hemoglobin content. This is a promising first step in the validation of a new optical breast imaging tool with functional and molecular imaging potential.

2752. Breast Cancer Characterization with Optical Spectroscopy Integrated Into an MR Breast Biopsy Plate Colin M. Carpenter1, Subhadra Srinivasan1, Brian W. Pogue1, Shudong Jiang1, Keith D. Paulsen1 1Dartmouth College, Hanover, New Hampshire, USA

Simultaneous optical spectroscopy and DCE-MR of breast cancer has been studied in simulation and in vivo to characterize breast tumors. The optimization of the patient interface has been investigated, comparing a circular fiber interface and an attachment to a breast biopsy grid. In vivo results of both healthy and abnormal breast exams taken with both approaches are presented.

Poster Sessions

450

2753. Diffusion-Weighted Imaging: A Valuable Aid for the Determination of the Margin of Breast Carcinoma Yili Zhang1, Xiaoyan Huang1, Hongwen Du1, Yun Zhang1, Xin Chen2, Peng wang2, Youmin Guo3 1First Hospital of Xi¡¯an Jiaotong University, Xi¡¯an, People's Republic of China; 2Second Hospital of Xi¡¯an Jiaotong University, Xi¡¯an, People's Republic of China; 3Beijing Chao-Yang Hospital, Captial Medical University, Beijing, People's Republic of China

In our present study we first applied DWI to compare the ADC value of malignant tumor with that of the peripheral tissue. We found that from the center of tumor to its peripheral tissue, the ADC values gradually increased and 10 mm away from the visible margin of tumor in image outwards, there existed an invisible tumor margin, which we regarded as the so called biological margin. Thus, the excision scope should be at least 10 mm from the visible border so that the excision can be complete.

2754. DCE-MRI and Dynamic 15O-Water PET/18F-FDG PET for Assessing Tumor Vascularity, Histology, and Response to Neoadjuvant Savannah C. Partridge1, Peter R. Eby1, Steven W. White, Robert K. Doot, Brenda F. Kurland, Erin K. Schubert, Lisa K. Dunnwald, Constance D. Lehman, David A. Mankoff 1University of Washington, Seattle, Washington, USA

Dynamic contrast-enhanced MRI (DCE-MRI) and positron emission tomography (PET) are two functionally different imaging modalities predictive of response to neoadjuvant therapy in breast cancer. However, the extent of their agreement or discordance for tumor characterization is not well understood. We investigated the combination of DCE-MRI enhancement kinetics, 15O-water PET measures of blood flow, and 18F-FDG PET metabolic measures for characterizing human breast tumors. We found PET and DCE-MRI vascular measures were well correlated, and FDG PET provided complementary metabolic information. Several PET and DCE-MRI measures were significantly associated with tumor grade, ER/PR status, and pathologic response to neoadjuvant treatment.

2755. Nonrigid Registration for Motion Correction in Contrast-Enhanced MR Breast Imaging: Comparison Between Finite Element and Free Form Deformation Method Alphonso William Magri1, Andrzej Krol2, Mehmet Unlu1, James Mandel1, Gwen Tillapaugh-Fay2, Wei Lee2, Edward Lipson1, David Feiglin2 1Syracuse University, Syracuse, New York, USA; 2SUNY Upstate Medical University, Syracuse, New York, USA

In order to improve diagnostic accuracy for evaluation of breast tissue lesions detected in contrast-enhanced MR imaging one needs to perform nonrigid registration of consecutive time frames. The objective of this study was to compare the quality of registration accomplished by two different approaches: Finite Element Method (FEM) with fiducial skin markers and a Free Form Deformation (FFD) method. We conclude that FFD plus dedicated hardware and software that would reduce execution time is a method of choice for nonrigid registration of consecutive time frames in dynamic MR breast imaging.

2756. Combining Complex In-Phase and Opposed-Phase Data to Improve Contrast in Dynamic MR Mammography Karl-Heinz Herrmann1, Alexander Rauscher2, 3, Pascal Baltzer1, Diane Renz1, Jürgen R. Reichenbach1 1Friedrich-Schiller-University, Jena, Germany; 2University of British Columbia, Vacouver, Canada; 3Friedrich-Schiller University , Jena, Germany

Simultaneous acquisition of in-phase (ip) and opposed-phase (op) data of a time series allows to create a multitude of new image combinations, which may generate new beneficial or even superior contrasts compared to a standard ip image magnitude subtraction. We are investigating two particular promising new contrasts on in vivo patient data, one acting as a contrast-to-noise booster in comparison to regular magnitude ip-subtraction. The other contrast combines anatomical information, especially Cooper ligaments and tissue boundaries, with a contrast amplification for partially volumed lesion boundaries which might otherwise be difficult to detect. The two contrasts can also be integrated into one image to reduce the number of total images.

2757. Diagnosis of Breast Lesions Utilizing an Integrated Model-Free and Model-Based Analysis of DCE-MRI Erez Eyal1, Daria Badikhi1, Edna Furman-Haran1, Fred Kelcz2, Hadassa Degani1 1Weizmann Institute of Science, Rehovot, Israel; 2University of Wisconsin Hospital and Clinics, USA

The purpose of this work is to evaluate a new method for diagnosing breast lesions that integrates principal component analysis with the three time point model based analysis. DCE-MR images of 69 lesions, 38 benign and 31 malignant were analyzed by this method. Two specific eigen-vectors were shown to be sufficient for describing the time dependent patterns of contrast enhancement. They were transformed by rotation to reflect physiological behavior using a correlation with the 3TP method. The reproducibility of the patterns (for a standardized protocol) and the fast image processing makes it an attractive choice for CAD.

2758. Evaluation of the Diagnostic Accuracy of Computer-Aided Detection of Breast Cancer Using MRI at Different Temporal Resolutions Jacob Levman1, Petrina Causer1, Ellen Warner1, Don Plewes1, Anne L. Martel1 1Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Canada

Breast MRI is likely to continue to play a significant diagnostic clinical role. Researchers are developing new techniques to improve the spatial resolution, temporal resolution and signal to noise ratio of breast MRI. This study evaluates the benefit of increased temporal resolution on our ability to discriminate between malignant and benign lesions using computer-aided detection tools. This study compares two protocols (with high and low temporal acquisitions) by comparing their receiver operating characteristic curve areas. Results show little difference between the two protocols indicating that researchers should focus their efforts on improved spatial resolution and signal to noise ratio.

Poster Sessions

451

Prostate Cancer Hall D Monday 14:00-16:00

2759. High B-Value Diffusion-Weighted MR Images of Urothelial Cancer Mayumi Takeuchi1, Kenji Matsuzaki1, Hiromu Nishitani1 1University of Tokushima, Tokushima, Japan

We evaluated urothelial cancers by high b-value diffusion-weighted images (DWI) and corresponding isotropic ADC maps. All 45 urothelial cancers (two renal pelvic, 15 ureteral and 28 bladder cancers) showed very high intensity on DWI (ADC=1.43 +/- 0.29). The fusion images in combination of DWI and MR Urography are useful in tumor detection and in evaluation of tumor extent in the entire urinary tract. In bladder cancers DWI can provide useful information for the evaluation of depth of invasion.

2760. Diffusion-Weighted Imaging for Detection and Staging of Urothelial Neoplasms Mohit Naik1, Andew D. Hardie1, Hersh Chandarana1, Cristina H. Hajdu1, Vivian Lee1, Bachir Taouli1 1NYU Medical Center, New York, New York, USA

In this study we retrospectively evaluated the performance of DWI for detection and staging of urothelial neoplasms. All lesions were identified on high b-value DWI images and ADC of tumor was significantly lower than ADC of reference organs (urine and kidney). In addition, rADC (relative ADC=ADC tumor/ADC urine) demonstrated strong correlation with tumor stage and 100% accuracy for predicting stage III/IV tumors.

2761. Comparison of Quantification Approaches in Diffusion Tensor Imaging of Prostate Cancer at 3T Yukihisa Takayama1, Guang Jia1, Steffen Sammet1, Zarine K. Shah1, Ketul K. Shah1, Pankaj P. Dangle1, Wenle P. Wang1, Rafael E. Jimenez1, Vipul R. Patel1, Michael V. Knopp1 1The Ohio State University, Columbus, Ohio, USA

Apparent diffusion coefficient (ADC) values can be approximated by using at least two b-values but actually Diffusion-weighted images acquired with different b-values show an exponential decay, so an appropriate exponential fitting curve to calculate ADC may be more sensitive to differentiate prostate cancer. Diffusion tensor imaging has also been used as a new method to describe the diffusion in the prostate. In this study, we calculated ADC values using mono-exponential data fit and investigated if this method can help to delineate prostate cancer. DTI was also investigated if it can be additional information for prostate cancer diagnosis.

2762. Diffusion-Weighted Imaging of the Prostate at 3T Using High B-Factors Julie Absil1, Nathalie Hottat1, Thierry Metens1, Celso Matos1 1ULB - Hôpital Erasme, Brussels, Belgium

We investigated the use of DW-imaging of the prostate at 3T without endorectal coil and involving b-values superior to 1000s/mm². 31 patients with suspicious PSA-level or DRE underwent MR examinations on a 3T Philips system, using the cardiac-coil. DWI was applied with 5 b-factors : 0, 1000, 1500, 2000, 2500s/mm². ADCs were calculated with all five b-values, with b=1000 to 2500 and with b=0-1000s/mm², and results were compared to histopathology (TRUS-guided biopsies). DWI had a high sensitivity (87.5%) for the detection of suspicious lesions, but malignant and benign lesions could not be differentiated by their ADC (specificity = 53.3%).

2763. Tumor Volume Measurement in Prostate Cancer Using Diffusion-Weighted Imaging: Initial Results Yousef Mazaheri1, Amita Shukla-Dave1, Hedvig Hricak1, Samson W. Fine1, Jingbo Zhang1, Victor Reuter1, Glorai Inurrigarro1, Joanna Grater1, Kristen Laura Zakian1, Jason A. Koutcher1 1Memorial Sloan Kettering Cancer Center, New York, New York, USA

We present a method to measure prostate tumor volume using ADC maps generated from DW images. The method uses a combined statistical ADC threshold and voxel cluster approach to measure prostate tumor volume. Our initial results suggest that tumor volumes measured on ADC maps correlate significantly with tumor volumes measured on histopathology.

2764. Assessment of Prostate Cancer Aggressiveness Using Diffusion Weighted Imaging Yousef Mazaheri1, 2, Amita Shukla-Dave1, Hedvig Hricak1, Samson W. Fine1, Jingbo Zhang1, Victor Reuter1, Gloria Inurrigarro1, Joanna Grater1, Liang Wang1, Kristen Laura Zakian1, Jason A. Koutcher1 1Memorial Sloan Kettering Cancer Center, New York, New York, USA

We present the results of a lesion-based analysis using whole-mount step-section pathology after radical prostatectomy as the standard of reference to investigate whether the apparent diffusion coefficient (ADC) values calculated from diffusion weighted images of prostate cancer lesions correlate with lesion Gleason scores.

2765. Comparison of Apparent Diffusion Coefficients Derived from Histology-Defined Versus T2-W Defined Regions in Prostate Cancer Geoffrey S. Payne1, Sophie Riches1, Veronica Morgan1, Cyril Fisher2, Sarb Sandhu2, Nandita M. desouza1 1Royal Marsden Hospital and Institute of Cancer Research, Sutton, UK; 2Royal Marsden Hospital, London, UK

Tumours in prostate cancer may be identified directly using T2-weighted MRI, or indirectly by mapping the tumor region on a histological slice on to the T2-weighted image, using suitable warping and landmarks. This study was designed to investigate the degree of overlap and identify the consequent effect on values of tumor ADC. In 20 patients the average lesion size identified by T2w MRI was about half that identified by histology, with just under 50% overlap between them. Compared with peripheral zone, histologically-identified tumor ADC was reduced more than T2w-MRI identified tumor ADC. The mechanistic cause of this deserves further attention.

Poster Sessions

452

2766. Spectroscopic Imaging of Prostate Cancer: A Novel Spectrum Processing Approach and Comparison with the Step-Section Histology Jan Weis1, Håkan Ahlström1, Peter Hlavcak1, Michael Häggman1, Francsico Ortiz-Nieto1, Antonina Bergman1 1Uppsala University Hospital, Uppsala, Sweden

Verification of findings can be considered as the weakness of many MRSI studies of the prostate cancer. The majority of previous reports have used sextant biopsy. Biopsy is, however, subject to sampling errors. Only a few studies used prostatectomy step section histology as the reference. This work addresses the novel spectrum processing approach based on the combination of vendor optimized spectrum preprocessing in the scanner and user independent time-domain spectrum processing in MRUI. Our objective was quantitation of (Cho+Cr)/Cit ratio in normal and pathologic human prostate and comparison of the results with histopathology after radical prostatectomy.

2767. Improved Prostate MRSI Employing a Conformal Voxel Technique Niranjan Venugopal1, 2, Boyd McCurdy, 13, Lawrence Ryner, 12 1University of Manitoba, Winnipeg, Canada; 2National Research Council Institute for Biodiagnostics, Winnipeg, Canada; 3CancerCare Manitoba, Winnipeg, Canada

A key component in the clinical utility of prostate MRSI is the effective suppression of periprostatic lipid signal to reduce contamination artifacts. We present the first application of conformal voxel magnetic resonance spectroscopy (CV-MRS) in prostate MRSI to improve the effectiveness of outer volume lipid suppression. This method uses up to twenty Very Selective Saturation (VSS) pulses, automatically positioned in three dimensions, to “conform” the excitation voxel to the shape of the prostate, effectively nulling signal from surrounding tissue. Using this technique results in a ~75% reduction in contaminating lipid and improved quality of spectra throughout prostate.

2768. Automated Prostate Cancer Detection from Magnetic Resonance Spectroscopy (MRS) Using a Hierarchical Non-Linear Dimensionality Reduction Scheme Pallavi Tiwari1, Mark Rosen2, Jeff Blume3, Jeff Weinreb, Anant Madhabushi4 1Rutgers University, New Brunswick, New Jersey, USA; 2University of Pennsylvania, Philadelphia, Pennsylvania, USA; 3Brown University, Providence, Rhode Island, USA; 4Rutgers, New Brunswick, New Jersey, USA

Automated segmentation of prostate MRS can be used to identify areas of cancer in prostate MRI/MRS at 1.5T.

2769. Quantitative Analysis of Pharmacokinetic Parameters Using DCE-MRI of Prostate from Patients with Prostate Cancer Before and After Intensity-Modulated Radiotherapy Patrik Zamecnik1, Christian Zechmann2, Frederik Lars Giesel3, Christian Thieke2, Stefan Delorme2 1German Cancer Research Center (DKFZ), Heidelberg, Germany; 2DKFZ, Heidelberg, Germany; 3DKFZ, heidelberg, Germany

The intensity-modulated radiotherapy (IMRT) is an effective option to treat prostate cancer. The aim of this work was to prove the changes of the dynamic pharmacokinetic parameters (amplitude, kep) in the prostate using DCE-MRI of patients with prostate cancer after IMRT compared to the values prior to radiotherapy in terms of definition of an effective control parameter. 24 men with histologically proved prostate cancer underwent a standardized MRI-examination before and after IMRT. In conclusion, kep showed a significant decrease after IMRT - this parameter is applicable for monitoring of intraprostatic changes after IMRT. Amplitude showed no significant changes after IMRT.

2770. A Method for Detailed Analysis of Prostate Motion Demonstrated with a Study of Bladder Filling Effect Ben Brooks1, Steven Yang1, Gary Cowin1, Matt Meredith1, Deming Wang1 1University of Queensland, Brisbane, Australia

As part of a larger study we aim to observe prostate motion under certain conditions. In this study we trial a new registration algorithm to find the translation and rotation of the prostate under bladder filling conditions. The results are compared to Centre of Mass displacments results from litrature and our own COM results.

2771. Significant Changes in Prostate Shape and Volume After Endorectal Coil Introduction, as Observed by 3T MR Imaging Stijn Wilhelmus Heijmink1, Tom W. Scheenen1, Emile N. van Lin1, Lambertus A. Kiemeney1, Jelle O. Barentsz1 1Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands

Endorectal coil (ERC) introduction as observed by 3T MR imaging changed all prostate diameters and volume significantly. Most particularly, the mean anteroposterior diameter was reduced by approximately one-sixth of its original diameter. The mean total prostate volume was decreased by 18%. This may cause difficulties and should be considered when using ERC-based MR images for MR-CT image fusion and radiation therapy treatment planning.

2772. Prediction of Extracapsular Extension of Of Prostate Cancer with Endorectal MRI: The Effects of Histological Tumor Size, Grade and Zonal Extent Liang Wang1, Jingbo Zhang1, Yousef Mazaheri Tehrani1, Ishill Nicole2, Chaya Moskowitz1, Hedvig Hricak1 1Memorial Sloan-Kettering Cancer Center, New York, New York, USA; 2Memorial Sloan-Kettering Cancer Center, New York, USA

To determine whether the sensitivity of MRI in detecting extracapsular extension of prostate cancer lesions is significantly affected by any of the following histological characteristics of the lesions: greatest diameter, greatest perpendicular diameter, bi-dimensional diameter product, Gleason grade, and zonal extent.

2773. Application of a “Shutter–Speed” Model to Analysis of Dynamic Contrast Enhancement in Prostate Tumours Martin Lowry1, Bashar Zelhof1, Martin D. Pickles1, Peter Gibbs1, Lindsay W. Turnbull1 1University of Hull, Hull, UK

DCE-MRI of the prostate at 3T was implemented using multiple flip angles, for T1 determination, and a rapid dynamic 3D acquisition. Pharmacokinetic analysis using a Fast-eXchange Regime model provided improved fitting accuracy and consistently increased values of Ktrans and Ve when compared to an Fast-eXchange Limit model. Values of tau, the mean intracellular lifetime of water, were significantly lower in tumour and BPH than in apparently normal peripheral zone.

Poster Sessions

453

2774. Computer-Aided Diagnosis of Prostate Cancer: Clinical Utility of Integrating Model-Free and Kinetic-Based Analysis of High Spatial Resolution Dynamic Contrast Enhanced 3 Tesla MRI B. Nicolas Bloch1, Erez Eyal2, Neil M. Rofsky1, Edna Furman-Haran2, Hadassa Degani2, Elizabeth M. Genega1, William C. Dewolf1, Glenn J. Bubley1, Robert E. Lenkinski1 1Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA; 2Weizmann Institute of Science, Rehovot, Israel

The aim of this work was to assess the clinical utility of principle component analysis (PCA) to analyze DCE images of the prostate, in comparison with model-based analysis (3TP) and whole mount histopathology as the reference standard. The temporal patterns in DCE MRI of the prostate are a linear combination of 3 orthogonal components, which were identified by PCA in 14 different patients as the three largest eigen vectors. The partition of enhancement patterns performed by PCA was similar to the partition obtained by the model based 3TP algorithm and showed a high spatial correlation with histopathology. PCA offers a computational fast, robust, model independent approach for analyzing DCE MRI and facilitates highly accurate non-invasive prostate cancer assessment.

2775. Minimizing Inflow Effect in Measured Arterial Input Function for Prostate DCE-MRI Yuxi Pang1, Marcelino Bernardo2, 3, Baris Turkbey3, Gregory Ravizzini3, David Thomasson4, Peter Choyke3 1Philips Medical Systems, Bethesda, Maryland, USA; 2SAIC-Frederick, Frederick, Maryland, USA; 3Molecular Imaging Program, National Cancer Institute, Bethesda, Maryland, USA; 4National Institutes of Health, Clinical Center, Bethesda, Maryland, USA

Analysis of T1-wighted dynamic contrast enhanced MRI (DCE-MRI) data based on the pharmacokinetic model (Generalized Kinetic Model, GKM) could provide key diagnostic information about prostate tissue perfusion1. In order to derive meaningful pharmacokinetic parameters, it is indispensable to know an accurate arterial input function (AIF) which represents the delivery of intravascular tracer to the tissue of interests. In practice, AIF is normally taken from either right or left femoral artery areas within imaging planes. However, due to the limited scan volume coverage, none polarized blood from outside imaging volume will flow through the imaging planes resulting in apparent decreased longitudinal relaxation times T1 and thus leading to an overestimation of AIF. In this work, we propose to apply an additional RF pulse to extend the imaging volume coverage for reducing this blood inflow effect.

2776. Experiences with the MRI Guided Prostate Biopy in Clinical Routine in Patients with Former Negative TRUS Biopsy Matthias Philipp Lichy1, David Schilling, Aristotelis Anastasiadis, Philipp Wagner, Arnulf Stenzl, Claus D. Claussen, Heinz-Peter Schlemmer1 1University of Tuebingen, Tuebingen, Germany

The MRI guided prostate biopsy is an invaluable add-on to the conventional TRUS biopsy, especially in cases with former negative biopsies, persisting / increasing PSA levels and suspicious MRI findings. It is a save and practical procedure, which can easily be integrated into clinical routine.

2777. Clinical Evaluation of a Novel, Near-Isotropic Resolution Volume Selective 3D FSE Pulse Sequence for Prostate MRI David W. Stanley1, Manojkumar Saranathan2, Marilyn B. Wood3, James F. Glockner3, Akira Kawashima3 1GE Healthcare, Rochester, Minnesota, USA; 2Global Applied Science Laboratory, GE Healthcare, Rochester, Minnesota, USA; 3Mayo Clinic, Rochester, Minnesota, USA

Conventional multi-slice 2D Fast Spin Echo (FSE) sequences obtained in three orthogonal planes aligned to optimally visualize the prostate are used to outline the contour and zone anatomy of the prostate gland and to reveal gross tumor extension to the seminal vesicles and neurovascular bundles. Until recently, 3D FSE with high spatial resolution has been impractical due to the blurring caused by long echo-trains. In this study, we investigated a novel, volume-selective near-isotropic 3D FSE pulse sequence and its potential as an adjunct and/or replacement to conventional multiplanar 2D FSE imaging.

2778. Diagnostic Accuracy of T2 Weighted MRI for Planning MRI Guided Prostate Biopsies – a Correlation with Whole-Mount Sections in 70 Patients Matthias Philipp Lichy1, Lonard Jurgschat, Joerg Hennenlotter, Ulrich Vogel, Aristotelis Anastasiadis, David Schilling, Arnulf Stenzl, Clauss D. Claussen, Heinz-Peter Schlemmer1 1University of Tuebingen, Tuebingen, Germany

T2w endoMRI can be used for planning and conduction of MRI guided prostate biopsies. Especially tumor lesions down to 0.5 cm, which are not assessable by ultrasound guided transrectal biopsy, can be assessed by this method.

2779. Prostate Magnetic Resonance Imaging (MRI) at 3 Tesla: Prostate Cancer Detection and Localization in Patients with Repeat Negative Biopsies Using High Spatial Resolution Dynamic Contrast Enhanced and T2-W MRI in Routine Clinical Practice Boris Nicolas Bloch1, Tania Velez1, Robert E. Lenkinski1, Herbert Y. Kressel1, Martin P. Smith1, Ivan Pedrosa1, Long Ngo1, William C. Dewolf1, Elizabeth Genega1, Martin Sanda1, Neil M. Rofsky1 1Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA

The aim of the study was to prospectively determine the value of high spatial resolution dynamic contrast enhanced (DCE-) with high spatial resolution T2 weighted (T2-W) endorectal(ER) coil magnetic resonance imaging (MRI) at 3 Tesla for detection and localization of prostate cancer in patients with repeat negative biopsies and raising prostate specific antigen (PSA) , using histopathology of the subsequent biopsy as the reference standard. This prospective study demonstrates that high spatial resolution 3 Tesla MRI improves positive prostate biopsy rates substantially by 16-48%, when compared to standard repeat biopsy. This data suggests that MRI can assist in the reduction of repeat negative biopsies in patients with raising PSA, foremost in patients with anterior (central gland) tumors, and can facilitate earlier appropriate treatment.

Poster Sessions

454

Advances in GI & Hepatobiliary Hall D Tuesday 13:30-15:30

2780. Metabolomic Characterization of Human Rectal Adeno-Carcinoma with Intact Tissue Magnetic Resonance Spectroscopy Kate W. Jordan1, Johan Nordenstam2, Christen B. Adkins1, Gregory Y. Lauwers1, Leo L. Cheng1, Michael Garwood2 1MGH/Harvard Medical School, Boston, Massachusetts, USA; 2University of Minnesota, Minneapolis, Minnesota, USA

We are investigating the utility of ex vivo intact tissue metabolomic profiles to differentiate biopsies from rectal tumors containing malignant cells from benign samples. This study was designed to test if metabolic characterization of intact, unaltered human rectal adeno-carcinoma specimens is possible using the high-resolution magic angle spinning proton (1H) magnetic resonance spectroscopy technique. We have found using this method on rectal biopsies does have the ability to metabolically characterize samples and differentiate between pathological features of interest. Future studies should determine its utility in in vivo applications for non-invasive pathological evaluations of suspicious rectal lesions.

2781. MR Elastography of Liver Tumors Sudhakar Kundapur Venkatesh1, 2, Meng Yin1, James F. Glockner1, Naoki Takahashi1, Roger C. Grimm1, Armando Manduca1, Richard L. Ehman1 1Mayo Clinic, Rochester, Minnesota, USA; 2National University of Singapore, Singapore, Singapore

Pre-operative imaging diagnosis of malignant liver lesions has increasingly become important because of availability of alternative treatment and expanded indications of hepatic resections. MRI is currently the modality of choice for characterization of liver tumors. However, some liver masses may remain indeterminate. We undertook a study to evaluate the role of MR Elastography, a technique for quantitatively assessing the mechanical properties of tissue, in imaging and characterization of liver tumors. Our results show that MRE is a promising, rapid non-invasive technique for differentiating benign and malignant tumors that can be easily added to complement routine MRI studies of liver.

Tumor Perfusion & Permeability: Methodology & Applications Hall D Wednesday 13:30-15:30

2782. Comparing the Effects of Different Pooled Arterial Input Functions on DCE-MRI Measurement Error Analysis Across Anatomical Locations Nina Tunariu1, Jane Taylor1, James Stirling1, James d'Arcy2, David J. Collins2, Simon Walker-Samuel2, Anwar R. Padhani1 1Mount Vernon Cancer Centre, Northwood, Middlesex, UK; 2Institute of Cancer Research, Sutton, Surrey, UK

In this study we examine the effects of different population arterial input functions (AIFs) on transfer constant estimates, measurement error, and on model fitting in liver, pelvis and breast tumours. Our analyses indicate that there is an improvement in reproducibility by using “more physiological” (non-Weinmann) AIFs at all anatomical sites. We also noted that tumours vary in the number of pixel failures and goodness of kinetic model fitting by anatomical location.

2783. Differences Between DCE-MR and DCE-CT in Prostate Cancer and Their Implications on the Choice of a Tracer Kinetics Model Jan Georg Korporaal1, C. A.T. van den Berg1, Cecile R. Jeukens2, G. Groenendaal1, Marco van Vulpen1, Peter Luijten1, Uulke A. van der Heide1 1University Medical Center Utrecht, Utrecht, Netherlands; 2Elkerliek Hospital, Helmond, Netherlands

Differences between DCE-MRI and DCE-CT in prostate cancer may exist, affecting the choice for a perfusion model. A quantitative comparison of the AATH model and Tofts model has been performed in 10 patients on both DCE-CT and DCE-MRI by fitting mean contrast enhancement curves of high-flow regions to both models. The AATH model fitted better to the DCE-CT curves, since arterial first pass peaks (FPP) were only visible on DCE-CT. For the Tofts model the parameters are equal for DCE-MRI and DCE-CT, although the model fails to describe the FPP on DCE-CT. The AATH model also yields similar results for DCE-MRI and DCE-CT, but some caution is required as the transit time shows significant differences.

2784. Short-Term Anti-Angiogenic Therapy Improves Tumor Microvascular Function: Investigation with Dynamic Contrast Enhanced MRI Ulrike Nöth1, Sebastian Strieth2, Gunnar Brix3, Marc Dellian2, Martin E. Eichhorn2 1Helmholtz Center Munich - German Reseach Center for Environmental Health, Neuherberg, Germany; 2Klinikum Großhadern, University of Munich (LMU), Munich, Germany; 3Federal Office for Radiation Protection, Neuherberg, Germany

Anti-angiogenic therapy by blocking VEGF signalling combined with chemotherapy is a novel strategy for clinical cancer treatment. One possible mechanism leading to an improved tumor microvascular function, and therefore, increased drug delivery during chemotherapy could be a “normalization” of tumor vessels after anti-angiogenic therapy. Aim of the study was to study tumor microvascular function in a highly vascularized melanoma in Syrian golden hamsters with dynamic contrast enhanced MRI upon anti-VEGF treatment and compare it to untreated control tumors.

Poster Sessions

455

2785. Quantification of Perfusion Change with Carbogen Breathing in a Subcutaneous Rat Tumour Model Using ASL and Comparisons with T2* Change, ADC and IAUC John Carr1, Daniel Bradley2, Geoff Parker1, David Buckley1, Jean Tessier2 1University of Manchester, Manchester, UK; 2AstraZeneca, Macclesfield, UK

ASL is shown to be a feasible method for measuring F in a subcutaneous tumour model and sensitive enough to quantify changes resulting from carbogen breathing. A positive correlation is shown between T2* change and F change due to carbogen (r = 0.68, p = 0.01) and between ADC and F (r = 0.67, p =0.04). No correlation was found between IAUC and F indicating IAUC measurements are dominated by CA leakage. In summary, a novel application of the ASL technique is demonstrated showing how ASL can be used in tumours outside the brain in animals and potentially in humans.

2786. Mapping of Viable of Tumor Regions Using Gd-DTPA DCE-MRI Minming Huang1, Mutian Zhang1, 2, Jenghwa Chang1, Carl H. Le1, Pat B. Zanzonico1, Humm John1, Jason A. Koutcher1, 3, Cliff C. Ling1 1Memorial Sloan Kettering Cancer Center, New York, New York, USA; 2Columbia University, New York, New York, USA; 3New YOrk, New York, USA

As part of our ongoing research program to develop and validate techniques for imaging of tumor hypoxia, we undertook this study using Gd-DTPA DCE-MRI co-registered with 18F-FMISO PET images to map the distribution of viable cells within tumors and thereby optimize the correlation between interstitial pO2 readings and PET-derived FMISO concentrations in tumors.

2787. Evaluation of a Model-Free Approach to Contrast-Enhanced MRI in Lung Tumors Frank Risse1, Tristan Anselm Kuder1, Christian Hintze1, Christian Fink2, Hans-Ulrich Kauczor1, Wolfhard Semmler1 1Deutsches Krebsforschungszentrum, Heidelberg, Germany; 2Medical Faculty Mannheim - University of Heidelberg, Mannheim, Germany

The signal after administration of a contrast agent is either analyzed directly or quantitatively using pharmacokinetic (PK) models. A simple approach to analyze contrast-enhanced MR perfusion images for a clinical setting that enables comparisons between follow-up examinations of patients without using a PK-model was evaluated by means of tumor simulations based of a PK-model. The examination of the hemodynamic conditions and their heterogeneity within tumors was feasible with the model-free approach. The calculated initial slope and the maxima are directly related to tumor flow and volume. The normalization with an AIF might enable an intra-individual comparison under therapy.

2788. A Data-Driven Methodology for Cross-Visit Sub-Segmentation of Tumours in DCE-MRI Studies Giovanni Alessandro Buonaccorsi1, James P B O'Connor1, 2, Chris J. Rose1, Caleb Roberts1, Angela Caunce1, Sue Cheung1, Yvon Watson1, Karen Davies1, Lynn Hope2, Alan Jackson1, Gordon C. Jayson2, Geoff J M Parker1 1University of Manchester, Manchester, UK; 2Christie Hospital, Manchester, UK

We describe an unsupervised data-driven method of cross-visit image segmentation for DCE-MRI time series data. We employed principal components analysis for dimensionality reduction then performed k-means clustering to generate segmentations that can be applied to 3-D parametric maps resulting from model-based or model-free analyses to derive per-cluster parameter statistics for data from a clinical study: each resulting cluster had a different visit-by-visit pattern of parameter values. On the basis of our results, we propose that our segmentation methodology will provide a useful objective means of following the evolution of tumour sub-compartments in response to treatment over a whole DCE-MRI study.

2789. Tracer Kinetic Analysis of a Simultaneous T1- And T2* Measurement in a Tumor Model Steven Sourbron1, Melanie Heilmann2, 3, Andreas Biffar1, Christine Walczak2, 3, Julien Vautier2, 3, Andreas Volk2, 3, Michael Peller1 1Ludwig-Maximilian-University Munich, Munich, Germany; 2Institut Curie, Orsay, France; 3INSERM, Orsay, France

Quantification errors are known to arise with T2* bolus-tracking MRI from the difference in relaxivity between artery and tissue, and tracer leakage effects. Here we assess these errors using a simultaneous measurement of T1 and T2* data in a tumor model. We find that (i) the difference in relaxivities leads to overestimation of flows- and volumes; (ii) T2* relaxivity is reduced during extravasation, which produces an underestimation in the transit times. We conclude that perfusion and permeability cannot be measured from T2* data alone, but that the combination with T1 produces previously unmeasureable parameters with high tissue sensitivity.

2790. Intraindividual Crossover Studies with Gadobenate Dimeglumine for Contrast-Enhanced MR Imaging of the Breast, Abdomen, and Vasculature Guenther Schneider1, Federica Pediconi2, Luigi Grazioli3, Michael V. Knopp4 1University Hospital of Saarland, Hamburg, Germany; 2University of Rome “La Sapienza”, Rome, Italy; 3University of Brescia, Brescia, Italy; 4Ohio State University, Columbus, Ohio, USA

In MRI crossover studies of the liver, breast, and vasculature, patients received 2 identical MR exams within 2-14 days, one with Gd-BOPTA and the other with comparator. For liver imaging, Gd-BOPTA provided additional diagnostic information and the possibility of using lower overall doses. In breast imaging, Gd-BOPTA depicted significantly (p=0.003) more lesions than Gd-DTPA, and lesions were significantly (p<0.001) more conspicuous, demonstrating the benefit of higher T1-relaxivity for this indication. From the carotid arteries to the peripheral vascular beds, Gd-BOPTA demonstrated superior vessel enhancement and conspicuity, particularly for depiction of smaller vessels.

Poster Sessions

456

Assessing Tumor Response to Therapy Hall D Thursday 13:30-15:30

2791. Evaluation of Early Docetaxel Effects in MCF7 Xenografts Using HR MAS, in Vivo MRS, DCE-MRI and ADC-Mapping Else Marie Huuse1, Line Rørstad Jensen1, Pål Erik Goa1, 2, Steinar Lundgren2, 3, Ingrid Synnøve Gribbestad1, Tone Frost Bathen1 1The Norwegian University of Science and Technology (NTNU), Trondheim, Norway; 2St. Olavs Hospital, Trondheim, Norway; 3NTNU, Trondheim, Norway

Sensitive methods to assess early treatment response are needed to obtain individualized patient protocols depending on the biological characterization of tumors. DCE-MRI, ADC-mapping, in vivo MRS and ex vivo HR MAS MRS of tissue samples combined with multivariate data analysis, have been used to study changes during tumor progression and early effects of docetaxel in MCF7 xenografts. Our findings indicate that docetaxel treatment cause a significant increase in water diffusion and distinct differences in the in vivo and ex vivo metabolite profiles of controls, docetaxel treated and tumors in early stage of progression.

2792. Methodological Improvements in Multi-Centre Phase I DCE-MRI Studies of Novel Antivascular Drug Treatments: Implications for Reproducibility and Quality Assurance N. Jane Taylor1, David J. Collins2, James A. d'Arcy2, J. James Stirling1, Toni Wallace2, Dow-Mu Koh2, Anwar R. Padhani1 1Mount Vernon Hospital, Northwood, UK; 2Royal Marsden Hospital, Sutton, UK

In order to optimise DCE-MRI for use in multicentre studies, we have developed an imaging procedure suited for this purpose (3D acquisition, good quality assurance and control (QA/QC), using attainable sequence parameters for different machines, as linear relationship as possible between the signal intensity and the contrast agent concentration, quantification of tissue T1 relaxation rates using the Wang method.) These modifications have improved transfer constant reproducibility by 30% compared with a previous 2D acquisition technique when performed at 2 sites. We recommend these modifications in order to improve test performance for assessing novel antivascular therapies in multicentre clinical trials.

2793. MRI Guided Anti-Tumor Therapy with Liposomal Prednisolone Phosphate Ewelina Kluza1, Daisy van der Schaft1, Willem Mulder2, Raymond M. Schiffelers3, Gert Storm3, Gustav J. Strijkers1, Klaas Nicolay1 1Eindhoven University of Technology, Eindhoven, Netherlands; 2Mount Sinai School of Medicine, New York, USA; 3Utrecht University, Utrecht, Netherlands

Therapy with liposomal prednisolone phosphate strongly inhibits tumor growth. Since the exact mechanism of this anti-tumor action remains unclear, we decided to perform MRI-guided therapy to bring further insight into the observed effects. Several MRI methods were applied. Diffusion MRI and T2 mapping did not show any sighificant changes in the parameters masured throughout the therapy. However, contrast enhanced T1-weighted imaging using RGD-targeted paramagnetic liposomes as a contrast agent showed significantly stronger signal enchancement in treated tumors compared to the control group. Massive contrast agnet accumulation suggests increased vascular permeability caused by the therapy.

2794. Development and Characterisation of a Tumour Specific Contrast Agent for In Vivo Imaging of Therapeutic Response Tammy Louise Kalber1, Nazila Kamaly, Stephanie Anne Higham1, Amy H. Herlihy1, Andrew D. Miller, Jimmy D. Bell1 1Hammersmith Hospital, Imperial College London, London, UK

A novel colchicine based conjugated gadolinium contrast agent (Gd.DOTA.Colchicinic acid) was synthesised and tested for its T1 relaxation ability and its efficacy as a therapeutic agent in vitro and in vivo. Phantoms and biological in vitro and in vivo data showed it to be an effective signal enhancer achieving a maximum of 96% T1 reduction when compared to controls. T1 enhancement was apparent in tumour bearing mice within 2 hours and was unchanged at 24 hours highlighting intratumoural changes in morphology. Histology confirmed that conjugation of Gd.DOTA reduced toxicity, but did not lose its efficacy as a tubulin binding agent.

2795. Cisplatin Treatment Monitoring by Sodium MRI Relaxometry at 4.7 T in Colorectal Tumors Implanted on Mice Carole D. Thomas1, 2, Mihaela Lupu1, 2, Christine Walczak1, 2, Andreas Volk1, 2, Joël Mispelter1, 2 1Institut Curie, Orsay, France; 2INSERM-U759, Orsay, France

Sodium MRI in conjunction with relaxometry may monitor non-invasively structural changes in tumors due to the quadrupolar characteristics of sodium nuclei. The purpose of this work was to follow the effect of cisplatin on colorectal tumors implanted in nude mice. Sodium MRI revealed necrosis, with a high contrast, due to the diminished cellular density and consequently an increase in extracellular sodium. Sodium relaxometry revealed a T2 increase consequently to cisplatin treatment as compared to control. The authors suggested that the relaxation constants modification was due to the cellular shrinkage induced by the apoptotic process triggered by cisplatin treatment.

2796. NMR Visible Cholesterol Content Predicts Ultimate Treatment Response in HCT-116 Xenografts Treated with Flavopiridol, CPT-11 or the Combination Jin-Hong Chen1, Yuhsin V. Wu1, Rachael O’Connor1, Bernadette U. Laxa1, Penelope DeCarolis1, Elliott R. Brill1, Samuel Singer1 1MSKCC, New York, New York, USA

Current methods for assessing therapeutic response are largely based on changes in tumor size after multiple cycles of chemotherapy and are often inaccurate. This study uses an ex-vivo NMR biomolecular analysis of tumor tissue following a single cycle of chemotherapy to predict ultimate therapeutic effect in a human-colon-cancer (HCT-116) xenograft model. The HCT-116 tumor responds to the treatment of cpt-11 or the combination of cpt-11/flavopiridol but only slightly to the flavopiridol alone. The NMR detected cholesterol measured 4 days after the first drug dose correlates with response and predicts ultimate treatment outcome in this model xenograft prior to any discernable change in tumor size. These results suggest that NMR visible cholesterol serves as an early biomarker of therapeutic response and would provide a more efficient approach for selecting active drug regimes.

Poster Sessions

457

2797. Evaluation of the Effects of Herpes Simplex Virus Thymidine Kinase (HSV-TK) Overexpression on 5-Fluoro-2'-Deoxy-Uridine Metabolism in Tumor Xenografts Using In Vivo 19F MR Spectroscopy Khushali Kotedia1, Ellen Ackerstaff1, Ligang Xing1, C. Clifton Ling1, Gloria C. Li1, Jason A. Koutcher1 1Memorial Sloan Kettering Cancer Center, New York, USA

Increased thymidine kinase (TK) activity may facilitate conversion of 5-fluoro-2’-deoxy-uridine (FUdR) to 5-fluorouracil (5-FU). In vitro growth inhibition studies showed that expression of HSV-TK/GFP fusion protein increased sensitivity to FUdR minimally in the rat prostate carcinoma model R3327-AT and three orders of magnitude in the rat glioma model RG2. Fluorescence imaging validated HSV-TK/GFP expression in vivo. In vivo 19F MRS of R3327-AT and R3327-AT/TK tumors demonstrated the conversion of FUdR to 5-FU whose catabolites appeared quickly. No fluoronucleotides were detected. RG2 and RG2/TK are being investigated to determine if their in vitro sensitivity to FUdR changes FUdR metabolism in vivo.

2798. Measuring ADC Reductions as an Early Response to Chemotherapeutic Treatment Lauren Jean Bains1, Jennifer H. Baker2, Andrew I. Minchinton2, Stefan Alexander Reinsberg1 1University of British Columbia, Vancouver, Canada; 2British Columbia Cancer Research Centre, Vancouver, Canada

MRI and histochemistry were used to monitor the response of colorectal cancer xenografts to treatment with tirapazamine, a hypoxia activated prodrug. The effect of tirapazamine on tumour diffusion characteristics was measured by mapping apparent diffusion coefficient (ADC) before and after treatment. Once ADC maps were aligned with BrdU/haematoxylin images of necrosis, it was found that tirapazamine caused a decrease in ADC in both necrotic and non-necrotic tissues. Mean tumour ADC was elevated in tumours which did not fully respond to treatment, indicating that ADC may be used as a predictor of tumour response to this hypoxia targeting agent.

2799. Quantitative Assessment of Glioma Therapy Efficacy Based on Diffusion Isotropy and Anisotropy Priya Goel1, Matthias Karrasch2, Jan den Hollander1, James M. Markert1, Louis Burt Nabors1, Narasimha Shastry Akella1 1University of Alabama at Birmingham, Birmingham, Alabama, USA; 2MediGene, Munich, Germany

An MR diffusion tensor decomposition technique is used to evaluate glioma therapy efficacy in vivo. Five patients each, undergoing “local” and “global” therapies are reported in this study. The approach is shown to permit longitudinal evaluation of therapy, as well as, comparison of two different therapeutic strategies. It is also shown that using the method for segmenting MR images allows in vivo characterization of tumor and surrounding tissue over the longitudinal course of treatment.

Ex Vivo MRS Studies of Tumor Metabolism Hall D Monday 14:00-16:00

2800. The Tumor Microenvironment Alters Choline Phospholipid Metabolism Detected by Comparing Cancer Cells with Tumors Noriko Mori1, Kristine Glunde1, Tomoyo Takagi1, Zaver Bhujwalla1 1The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA

Both tumor cells in culture and solid tumor models are useful tools to study cancer biology. Elevated phosphocholine (PC) and total choline (tCho) levels are common features in cancer cells and solid tumors. To understand the differences in choline phospholipid metabolism between tumor cells in culture and solid tumors, we compared 1H MRS of extracts from human prostate and breast cancer cell lines grown in culture and as solid tumors. PC/GPC ratios in highly malignant cancer cells in culture were significantly higher than in the corresponding solid tumors, indicating the importance of the tumor microenvironment in choline phospholipid metabolism.

2801. Essential Role of Phospholipase A2 in Phenylbutrate-Induced Activation of Phospholipid Metabolism Daniel-Joseph Leung1, 2, Nancy J. Beardsley1, Theresa M. Mawn1, Edward J. Delikatny1 1University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA

MR spectral changes induced by the differentiating agent phenylbutyrate (PB) in DU145 prostate adenocarcinoma cells include significant increases in mobile lipids, total choline, and glycerophosphocholine (GPC). A specific inhibitor of cytoplasmic phospholipase A2 (cPLA2) was used to determine the contribution of this critical mediator in arachidonic acid dependent cell signaling on the observed metabolic changes. AACOCF3 reversed PB-induced changes, specifically attenuating GPC formation and mobile lipid increases caused by PB. These results suggest that variations of PLA2 activity may play a role in the cellular response to differentiation therapy.

2802. Quantification and Comparison of Time-Dependent Changes in Mobile Lipid Resonances with Cellular Processes Dominik Zietkowski1, Thomas Eykyn1, Nandita Desouza1, Geoffrey Payne1 1The Institute of Cancer Research, Sutton, UK

This study investigates changes in the nature and degree of saturation of mobile lipid resonances (MLRs) in relation to phases of the cell cycle and to cellular processes such as proliferation, drug-induced apoptosis (paclitaxel, etoposide), growth arrest (apicidin) and necrosis (cytochalasin B) in Hela cells. MLR changes 24h after exposure to these drugs are much more rapid than in unexposed cells. Lipid profiles of growth-arrested and apoptotic cells are almost indistinguishable. Flow cytometry data suggests that MLR changes are not cell cycle dependent as cells arrested in G1 or G2/M phases of the cell cycle display similar lipid profiles.

Poster Sessions

458

2803. Multi-Drug Resistant Breast Cancer Cells Exhibit High Choline Kinase and Stem-Like Markers Marie-France Penet1, Tariq Shah1, Kristine Glunde1, Noriko Mori1, Zaver M. Bhujwalla1 1Johns Hopkins University School of Medicine, Baltimore, Maryland, USA

The two main causes of treatment failure and mortality in cancer patients are multi drug resistance (MDR) and tumor metastasis. Stem-like cancer cells are known to have increased drug resistance and contribute to tumor recurrence, but their metabolic characteristics are unexplored. Here we have investigated breast cancer stem-like cell markers and choline metabolism in MCF-7 cells resistant to adriamycin (MCF-7/Adr) that display a MDR phenotype. We found that MCF-7/Adr cells expressed a higher level of choline kinase with an increased phosphocholine / glycerophosphocholine ratio, and contained a higher fraction of CD44+/CD24- stem-like cells than MCF-7 wild-type cells.

2804. Metabolomic Differentiation of Thyroid Malignancies with Magnetic Resonance Spectroscopy of Tissue and Cytology Samples William Faquin1, Kate W. Jordan1, Christen B. Adkins1, Leo L. Cheng1 1Massachusetts General Hospital, Boston, Massachusetts, USA

Accurate classification of thyroid malignancies is difficult due to an inability to biochemically characterize tumors. In this study HRMAS 1HMRS is used to examine paired samples of thyroid tissue and cytology from patients with papillary carcinoma, follicular adenoma, and follicular carcinoma. Metabolomic profiles generated were able to accurately identify if cancerous cells were present, and to differentiate between the three malignancies.

Preclinical MRI Cancer Monitoring Hall D Tuesday 13:30-15:30

2805. Do All in Situ Cancers Progress to Invasive Disease? a First Look at Progression of Mammary Cancer from in Situ to Invasive Carcinoma in Vivo Sanaz Arkani Jansen1, Gillian Newstead, Suzanne Conzen, Marta Zamora, Thomas Krausz, Gregory Karczmar 1University of Chicago, Chicago, Illinois, USA

We investigate the progression of pre-invasive in situ mammary cancer into invasive cancer using a transgenic mouse model. We demonstrate that i) MRI can reliably detect in situ cancer (300 microns) and small, non-palpable tumors (< 1 mm), ii) MRI may be used to track the progression of breast cancer through the full range of development, from in situ to invasive carcinoma, and iii) some in situ lesions did not progress significantly during the study window. With these techniques, MRI could be used to assess efficacy of therapies on in situ and early invasive cancer.

2806. Measuring Brain Tumor Growth: a Combined BLI / MRI Strategy Sarah C. Jost1, Lynne Collins1, Joel R. Garbow1 1Washington University, St. Louis, Missouri, USA

In oncology research, small-animal models are critical for the developmentof effective therapeutic strategies. Magnetic Resonance Imaging (MRI)offers excellent anatomic tumor localization, and Bioluminescence imaging (BLI) offers an efficient method for identifying tumors early and monitoringgrowth and response to therapeutic intervention. Our experiences using acombination of BLI and MR imaging lead us to suggest a method for combiningthese two small-animal imaging modalities to select animals with similarpatterns of tumor growth for subsequent preclinical therapeutic or imagingbased studies while limiting confounding anatomic factors, such ashemorrhage or hydrocephalus.

2807. Characterization of Liver Lesions in a Mouse Model of Endocrine Tumors Using MRI Loredana Baboi1, Laurent Milot1, 2, Carole Lartizien1, Denis Grenier1, Colette Roche3, Jean-Yves Scoazec3, Frank Pilleul1, 4, Olivier Beuf1 1INSA-Lyon, Université Lyon 1, Villeurbanne, France; 2Hôpital Edouard Herriot, Lyon, France; 3Faculté de médecine RTH Laennec, Lyon, France; 4Hospices Civils de Lyon, Lyon, France

Endocrine tumors, with digestive localization, are tumors with variable forecast which are independent of their local and metastatic extensions. As the main cause of treatment failure in human, liver lesions is an important target for therapeutic intervention. Thus, the use of dedicated MRI protocols suitable to follow liver lesion evolution on an experimental model of endocrine tumors with liver dissemination is very valuable. The goal of this study was to assess the detection level and to characterize the liver lesions in an athymic nude mouse model, using a dedicated MRI protocol and an optimized synchronization strategy for high magnetic field strength. The experiments were performed at 7T using a dual cardiac-respiratory triggered heavily T2-weighted MR images. A longitudinal follow-up of hepatic lesions in a group of eight nude mice at stages D7, D12, D17 and D24 was carried out. The hepatic lesion volume fraction (HLVF) was quantified using an adaptive segmentation procedure based on a dual reference limit. First lesions were detected at stage D12. The HLVF increased significantly with stage. Characterization of cystic or non-cystic type of lesions was achieved using various TE images and T2 maps. Mean T2-values increased also significantly with stage.

2808. Intrinsic Susceptibility MRI of Chemically-Induced Rat Mammary Tumours: Relationship to Histological Assessment of Hypoxia and Fibrosis Lesley D. McPhail1, Simon P. Robinson1 1The Institute of Cancer Research, Sutton, UK

The transverse relaxation rate R2* (s-1) of chemically induced rat mammary tumours was quantified whilst the host breathed air and subsequently carbogen (95%O2/5%CO2), and the data correlated with subsequent quantitative histological analysis of the percentage of tumour hypoxia, determined from pimonidazole adduct formation, and collagen (fibrosis), assessed with sirius red staining. Baseline R2* positively correlated with subsequent carbogen-induced δR2*. Statistically significant negative correlations were found between pimonidazole staining and both baseline tumour R2* and carbogen-induced δR2*. Pimonidazole staining positively correlated with sirius red staining.

Poster Sessions

459

2809. Rapid Monitoring of Oxygenation by 19F Magnetic Resonance Imaging : Simultaneous Comparison with Fluorescence Quenching Benedicte F. Jordan1, Greg O. Cron2, Bernard Gallez1 1Université catholique de Louvain, Brussels, Belgium; 2Ottawa Health Research Institute, Ottawa, Canada

We developed an MRI fluorocarbon oximetry technique using snapshot inversion recovery (SNAP-IR) and compared it with fluorescence quenching fiber-optic probe oximetry (OxyLiteTM) performed simultaneously in experimental mouse tumors. Tumor pO2 was modified using carbogen or lethal doses of the anesthetic gas. The SNAP-IR pulse sequence allowed us to sample tumor oxygenation with an effective in-plane spatial resolution (1.88 mm) similar to that of FREDOM (1.25 mm) and with an acquisition time of 1.5 min, which is shorter than that of FREDOM (6.5 min). It could therefore be particularly suitable to monitor acute changes of pO2 in tumors.

2810. Image-Guided Molecular Targeting of COX-2 Using Cationic Liposomes Containing SiRNA and Multi-Modality Imaging Reporters Maria Mikhaylova1, Ioannis Stasinopoulos1, Yoshinori Kato1, Dmitri Artemov1, Zaver M. Bhujwalla1 1JHU ICMIC Program, The Johns Hopkins University, School of Medicine, Baltimore, Maryland, USA

Advances in molecular targeted therapy in cancer are driving the development of image-guided carriers such as liposomes to deliver siRNA, with the purpose of down regulating specific targets in cancer cells. We recently observed that siRNA mediated downregulation of COX-2 in metastatic MDA-MB-231 breast cancer cells resulted in a profound inhibition of tumor growth and experimental metastasis. In this study we are evaluating the use of cationic liposomes with MR and optical reporters to image the delivery of COX-2 siRNA in tumors.

2811. Sodium and Diffusion as Mediators of Tissue Conductivity L Tugan Muftuler1, Mark Jason Hamaura1, Orhan Nalcioglu1 1University of California, Irvine, California , USA

Studies have shown that the electrical impedance of malignant tumors is significantly different from those of normal and benign tissues. Since conductivity in tissues is mediated by ion movement, increase in ion concentration and their mobility are potentially the main factors. In the literature, increase in sodium content in tumors was reported. Similarly, a linear relationship between tissue conductivity and diffusion tensor was also reported. Therefore, we collected conductivity images based on MREIT, as well as sodium and diffusion weighted images and investigated the contribution of those factors to tumor conductivity.

2812. Measurements of T1-Relaxation in ex Vivo Prostate Tissue at 132 μT Sarah Busch1, 2, Travis Wong1, Michael Moessle1, 2, Michael Hatridge1, 2, Jeffry Simko3, Alex Pines1, 2, John Clarke1, 2 1University of California, Berkeley, California , USA; 2Lawrence Berkeley National Lab, Berkeley, California , USA; 3University of California, San Francisco, California , USA

Current technologies for imaging prostate cancer such as T2-weighted MRI and MRSI have limited clinical utility and are most useful for detecting metastasis and post-therapy recurrences. We have developed an MRI technology that takes advantage of increased T1-contrast at very low fields. Our system involves prepolarization at fields up to 150 mT and detection of the 5.6 kHz NMR signal with a Superconducting QUantum Interference Device. We have imaged ex vivo prostate specimens and determined the T1 contrast between different types of prostate tissue. Our preliminary results consistently show good differentiation between healthy and cancerous prostate tissue.

2813. Functional Apparent Diffusion Coefficient Mapping the Uptake of Tumor-Targeting Bombesin Probes in Human Breast and Prostate Cancer Xenografts Lixin Ma1, 2, Ashley Brown, Naresh Kujala, Huifang Zhai, Charles Smith, Said Figureoa, Ping Yu, Timothy Hoffman, Wynn Volkert 1University of Missouri, Columbia, USA; 2VA Biomolecular Imaging Center, The Harry S. Truman Memorial Veterans’ Hospital, Columbia, USA

Cancer receptor-targeting molecular imaging probes and radiopharmaceuticals provide a means to early detection and targeted therapeutic interventions of malignancies by recognition of receptors uniquely over-expressed on human cancer cells. Bombesin is a 14-amino acid peptide that shows high affinity and specificity for gastrin releasing peptide receptor (GRPr). The GRPr is over-expressed on many human cancer cell lines including breast, prostate, colon, and small cell lung cancers. We and others have recently developed a series of BBN conjugates for fluorescent, SPECT and PET imaging of human breast and prostate cancer cells1,2. In this current study we applied magnetic resonance imaging (MRI) to investigate the relationship of apparent diffusion coefficient (ADC) map and the uptake distribution of florescent or radio-labeled bombesin conjugates in breast and prostate tumor xenografts.

Brain Tumor: Spectroscopy, Susceptibility & Functional MRI Hall D Wednesday 13:30-15:30

2814. Serial Assessment of Lactate in GBM Patients Undergoing Treatment Using Lactate-Edited 3D 1H MR Spectroscopic Imaging at 3T Ilwoo Park1, 2, Susan M. Chang2, Sarah J. Nelson1, 2 1University of California Berkeley/San Francisco, San Francisco, California , USA; 2University of California, San Francisco, California , USA

Lactate may be a valuable predictive marker for treatment outcome. The goal of this study is quantitative and qualitative assessment of lactate prior to and during radiation/chemo treatment in GBM patients using a previously developed lactate-edited 3D MRSI at 3T. Normalized lactate was significantly different between progressing and non-progressing patients, and the location of tumor recurrence coincided with the regions of lactate appearance at earlier exams with no signs of recurrence at the time of progression. It suggests that monitoring lactate may assist in characterizing tumor tissue and predicting the outcome of treatment for GBM patients.

Poster Sessions

460

2815. Lactate Production in Human Brain Tumor; Detection by 13C MRS at 3T Jannie P. Wijnen1, Dennis W.J. Klomp1, Albert J.S. Idema1, Bastiaan E. Galan1, Arend Heerschap1 1Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands

This study demonstrated the in vivo lactate production in a glioblastoma multiforme in a patient for the first time. We used localized single channel distortionless enhanced polarization transfer (SC-DEPT) 13C MR Spectroscopy at 3T with venous infusion of 1-13C labeled glucose. During an euglycemic clamp lactate labeled at the C3 position was detected in the voxel located in the tumor after approximately 20 minutes of 1-13C-glucose infusion. In the contra lateral voxel no lactate was detected, but much more formation of compounds downstream of lactate.

2816. High Resolution Fast Elliptical SENSE MRSI of Gliomas at 7T Esin Ozturk-Isik1, Wei Bian1, Janine Marie Lupo1, Duan Xu1, Radhika Srinivasan1, Ilwoo Park1, 2, Kate Hammond1, 2, Daniel B. Vigneron1, 2, Susan M. Chang1, Sarah J. Nelson1, 2 1University of California at San Francisco, San Francisco, California , USA; 2University of California at San Francisco and Berkeley, San Francisco, California , USA

Higher SNR at 7T can be traded for better spatial resolution to reduce the partial voluming effects for MR spectroscopic imaging of patients diagnosed with brain tumors. However, more phase encoding steps would be necessary to achieve higher spatial resolution using conventional PRESS MRSI localization. In addition, MR spectroscopic imaging at 7T requires a longer scan time due to the longer repetition times to avoid signal saturation. In this study, we propose high resolution MR spectroscopic imaging of glioma patients at 7T with a scan time of 6 minutes using elliptical SENSE technique.

2817. In Vivo and Ex Vivo 1H MRS Metabolite Profiles of Gliomas Franklyn A. Howe1, Kirstie S. Opstad1, B. Anthony Bell1, John R. Griffiths2 1St George's, University of London, London, UK; 2Cancer Research UK Cambridge Reseach Institute, Cambridge, UK

Knowledge of glioma grade aids treatment selection and patient prognosis. Metabolite ratios determined by 1H MRS are still used as measures of tumour grade, as an alternative to invasive biopsy. We have used in vivo and ex vivo 1H MRS and histopathology to quantify and model metabolite levels in gliomas. As well as variability in cell density and necrosis, there is metabolic variability that renders individual metabolite ratios and metabolite concentrations unsatisfactory biomarkers. For gauging glioma grade, pattern recognition analysis of all metabolites should generally be used.

2818. Proton MR Spectroscopy Reveals Elevated Myo-Inositol and Glutamine in the Contralateral Cerebral Hemisphere of Patients with Untreated Glioblastoma Multiforme Peter Dechent1, Hans Christoph Bock1, Arne Wrede1, Jan-Hendrik Buhk1, Alf Giese1, Gunther Helms1, Jens Frahm2, Herwig Strik1, Michael Knauth1, Kai Kallenberg1 1University Göttingen, Göttingen, Germany; 2Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut fuer biophysikalische Chemie, Göttingen, Germany

Glioblastoma multiforme (GBM) is the most common primary brain tumor with invasive growth and mainly of astrocytic origin. Previous studies in GBM patients identified tumor cells in macroscopically normal brain parenchyma. We used localized proton MRS to assess alterations of cerebral metabolite within the contralateral hemisphere of GBM patients as potential markers of GBM cells. MRS revealed elevated concentrations of myo-inositol and glutamine in GBM patients relative to control subjects as well as low-grade glioma patients. This finding most likely represents a mild astrocytosis indicating early neoplastic changes in line with reports of glioma cells in otherwise inconspicuous brain parenchyma.

2819. Clinical Feasibility of 1H Spectroscopic Imaging of Brain Tumors and Its Fusion with 3D Anatomical Datasets Martin Krssak1, Georg Widhalm1, Stephan Gruber1, Wolfgang Dietrich1, Stephan Wolfsberger1, Daniela Prayer1 1Medical University of Vienna, Wien, Austria

Clinical feasibility of 2D spectroscopic imaging and possibility of integration of metabolic maps with 3D anatomical data was evaluated in different regions of human brain in 25 patients with tumors. SI yielded robust data from intracerebral tumors positioned above and in the height of lateral ventricles. This data could be used for the integration into neurosurgery planning with the help of additional multi-slice T2weighted data set into 3D T1weighted anatomic data. Additional shimming procedure and/or special selection of spectroscopic VOI has to be considered for the SI measurements of the meningial tumors and/or lesions near the skull (base).

2820. Gadolinium Effect on Choline Signal in Brain Tumors as a Function of T1 Enhancement Maria Otaduy1, Rita Pincerato1, Eduardo Lima1, Katia Pincerato1, Luciana Borges1, Claudia Leite1 1Medical School of the University of São Paulo, São Paulo, Brazil

Choline measured by MRS is a tumor marker and its quantitation is important for diagnostic and follow up purposes of brain tumors. It has been described that paramagnetic contrast administration has the potential to change its intensity. Some experimental studies suggest that Gd has a minimal, if any effect on Cho signal. In our study we observed Cho changes after Gd injection as a function of T1 enhancement, which indirectly reflects Gd concentration, and our results are in agreement with theoretical simulations that show Cho changes to be strongly dependent on the Gd concentration reaching the tissue.

2821. Using 7T Susceptibility-Weighted Imaging to Aid in the Characterization of High-Grade Gliomas Janine M. Lupo1, Susan M. Chang1, Sarah J. Nelson1 1University of California, San Francisco, USA

Susceptibility-weighted imaging (SWI) is a powerful tool for high resolution imaging of the vasculature, allowing the detection of vessels or microhemorrhages as small as 100-200 μ at 7 Tesla. This study investigated the unique contrast present in SWI images of high-grade glial tumors by analyzing the overlap of 7T SWI hypointensity with the T2 hyperintensity region, contrast enhancing lesion, and perfusion abnormality at 3T. The addition of SWI highlighted heterogeneity within the contrast enhancing lesion and regions of elevated blood volume and/or microvascular leakage.

Poster Sessions

461

2822. Evaluation of Astrocytic Brain Tumors with 7T Versus 1.5T MRI Christoph Moenninghoff1, 2, Oliver Kraff1, 2, Jens M. Theysohn1, 2, Stefan Maderwald1, 2, Elke R. Gizewski1, 2, Jens P. Regel1, Mark E. Ladd1, 2, Michael Forsting1, 2, Isabel Wanke1, 2 1University Hospital Essen, Essen, Germany; 2University Duisburg-Essen, Essen, Germany

Twelve patients with histologically confirmed astrocytic brain tumors (WHO grade II-IV) underwent pre-treatment MRI at 1.5T and 7T. T 2, PD and T2* weighted images were performed. The signal gain of 7T MRI was used to achieve a higher spatial resolution. Twelve gliomas were identified by both MR modalities. Due to the increased susceptibility assumed microvascularity and microhemorrhages were superiorly visualized in 80% of 10 high-grade gliomas by 7T MRI in comparison to 1.5T MRI. As angiogenesis is one marker for tumor aggressiveness 7T MRI might become a valuable tool for glioma grading and assessment of tumor microvascularity in vivo.

2823. BOLD Response in Pediatric Medulloblastoma Patients During Radiation Treatment Ping Zou1, Thomas Merchant1, Amar Gajjar1, Robert Ogg1 1St. Jude Children's Research Hospital, Memphis, Tennessee, USA

Visual fMRI was used to evaluate the acute effect of craniospinal radiation on the BOLD response in children being treated for medulloblastoma. Activation in the primary visual cortex was evaluated at four time-points during the six-week course of radiation therapy (RT). The activated brain volume decreased significantly (p = 0.02) during the first week of RT, and remained low in the following weeks of RT. The change in BOLD response suggests an early acute effect of RT on hemodynamic responses to visual cortex activation.

2824. Evaluation of Reproducibility of FMRI Maps in Patients with Proven Low-Grade Brain Neoplasms Rachel DiAnne McKinsey1, Gabe Heredia2, Sean Fain2, Beth Meyerand2, Wolfgang Tome2 1University of Wisconsin Madison, Madison , USA; 2University of Wisconsin Madison, Madison, USA

The purpose of this study is to demonstrate the test re-test reliability of fMRI within subjects with benign and biopsy proven low-grade neoplasms. FMRI activation maps with 3 different thresholds (selected standard and +/- 20%) were generated for 9 subjects with benign and biopsy proven low-grade brain neoplasms using a GE Signa 1.5T magnetic resonance imaging (MRI) scanner. The imaging protocol included a 3DSPGR T1 brain volume, and 8 BOLD-weighted functional scans. Expected fMRI responses were examined in the lateral inferior/middle frontal gyri, bilateral superior temporal gyri, bilateral primary sensorimotor cortices, and posterior occipital pole.

ELECTRONIC MULTIMEDIA POSTERS Vascular Hemodynamics Hall D Monday 14:00-16:00

14:00 2825. Flow Sensitive MRI in a Realistic Model System of the Thoracic Aorta with Aortic Coarctation Ramona Lorenz1, Aurélien F. Stalder1, Jelena Bock1, Dominic Klausmann2, Christoph Benk1, Jürgen Hennig1, Michael Markl1 1University Hospital Freiburg, Freiburg, Germany; 2University Freiburg, Freiburg, Germany

The purpose of this study was to establish a realistic model system for the evaluation of hemodynamics consequences of aortic coarctation with different stenosis grades. Flow sensitive 4D MRI was performed within a realistic rapid prototyping vascular model of the thoracic aorta with attached flexible stenosis in the descending aorta which was integrated into a pulsatile flow circuit. A novel approach for generating realistic pulsatile waveforms was realized by a pneumatically driven VAD (ventricular assistant device) pump system. The study presents an evaluation of the impact of stenosis grade on local and global flow dynamics.

14:30 2826. Flow Sensitive 4D MRI: Descending Aortic Retrograde Flow and Embolization Risk in Acute Stroke Patients Michael Markl1, Christoph Strecker2, Patrick Dudler2, Andrea Nußbaumer2, Jelena Bock1, Aurelien F. Stalder1, Alex Frydrychowicz1, Anna L. Stroh3, Cornelius Weiller2, Jürgen Hennig1, Andreas Harloff2 1Dept. of Diagnostic Radiology, Medical Physics, University Hospital, Freiburg, Germany; 2Dept. of Neurology, University Hospital, Freiburg, Germany; 3Dept. of Cardiology, University Hospital, Freiburg, Germany

Flow-sensitive 4D MRI allows the detailed visualization of both physiological and pathological 3D aortic blood flow characteristics and was used to determine the role of retrograde flow in the descending aorta (DAo) in patients with acute embolic stroke. Our findings demonstrate a high incidence of retrograde flow in the proximal DAo suggesting that complex DAo plaques should be considered as a novel high-risk embolic source in patients with undetermined stroke etiology.

15:00 2827. Analysis of 3D Flow Dynamics in a Ventricular Assist Device by Flow Sensitive 4D MRI Michael Markl1, Ramona Lorenz1, Jelena Bock1, Christoph Benk2, Dominic Klausmann2, Alex Frydrychowicz1, Jürgen Hennig1, Friedhelm Beyersdorf2 1Dept. of Diagnostic Radiology, Medical Physics, University Hospital, Freiburg, Germany; 2Dept. of Cardiovascular Surgery, University Hospital, Freiburg, Germany

The assessment of flow characteristics inside ventricular assist devices (VADs) using MRI techniques may provide insight into the mechanisms underlying the high rate of thrombo-embolic events after VAD implantation. These investigations may form the basis to optimize the device’s design and its need for anticoagulation. The purpose of this study was to integrate a clinical routine VAD into a flow circuit with realistic geometric and pulsatile inflow conditions. Flow sensitive Magnetic Resonance Imaging (MRI) at 3 Tesla permitted the detailed analysis of local and global 3D flow dynamics in a realistic environment.

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Poster Sessions

462

15:30 2828. Diameter-Dependence of Aortic Hemodynamics: Does Size Matter? Alex Frydrychowicz1, Alexander Berger1, Aurélien F. Stalder1, Maximilian F. Russe1, Andreas Harloff1, Mathias Langer1, Jürgen Hennig1, Michael Markl1 1University Hospital Freiburg, Freiburg, Germany

It was the aim of this study based on flow-sensitive 4D MRI to analyze the diameter dependence of aortic hemodynamics with respect to characteristic blood flow patterns such as time to maximum arterial flow, duration of backward flow, number of vortices, and the presence of helical flow, which can be correlated to wall shear stress (WSS) and oscillatory shear index (OSI). The results of this study indicate the method¡¯s potential to identify characteristic, diameter dependent, aortic flow patterns. In a cohort of 62 individuals which were subgrouped by the diameter of the ascending aorta (SAD-group ¡Ü 3.5cm < LAD-group) we showed that the size of the aorta influences the hemodynamic properties.

14:00 2829. Multi-Dimensional Velocity Field Reconstruction from Sparsely Sampled 3D Phase Contrast MRI Kartik Sivaram Sundareswaran1, Dave Harold Frakes1, Mark Fogel2, Oskar Skrinjar1, Ajit P. Yoganathan1 1Georgia Institute of Technology, Atlanta, Georgia, USA; 2Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA

A new technique for velocity field reconstruction is presented in this paper that utilizes blood flow incompressibility as a property for estimating continuous flow field representation in blood vessels using a stack of contiguous phase contrast MRI. The methodology has been tested on 15 in vivo datasets of patients with a single ventricle circulation, and the results indicate superior qualitative and quantitative velocity reconstruction compared to other traditional techniques for flow reconstruction from PC MRI. This opens up new avenues for higher order analysis (vortex structures, energy loss) of PC MRI flow fields.

14:30 2830. In Vivo MR Determination of Flow Fields in Patients with Intracranial Aneurysms Using 7D PC-MRI Gabriel Acevedo-Bolton1, Alastair Martin1, Vitaliy Rayz1, Loic Boussel1, David Saloner1, 2 1UCSF, San Francisco, California , USA; 2VAMC San Francisco, San Francisco, California , USA

7D PC-MRI was used to measure and map the blood flow within intracranial aneurysms in vivo. These flow results were compared with in vitro reproductions and with the predictions of computational fluid dynamics(CFD) models. It was found to be essential to determine all three components of the velocity to adequately visualize the complex flow structures

15:00 2831. Patient-Specific Hemodynamics of the Descending Aorta: Combination of CFD and 4D Flow-Sensitive MRI Aurélien F. Stalder1, Zhenyu Liu2, Michael Markl1, Jürgen Hennig1, Jan Korvink2 1University Hospital Freiburg, Freiburg, Germany; 2University of Freiburg, Freiburg, Germany

Flow-sensitive 4D MRI allows in-vivo 3D blood flow visualization and flow parameter estimation but is limited by spatio-temporal resolution and measurement errors. In contrast, Computational Fluid Dynamics (CFD) can compute very accurate flow fields from modeled arteries but depends on the validity of the hemodynamic model and boundary conditions. We show for the first time an integration of 4D flow-sensitive MRI and CFD into a single framework. A combination of those 2 complementary approaches offers reciprocal validation possibilities and has the potential to refine flow measurements which may result in more accurate quantification of complex in-vivo hemodynamic phenomena.

15:30 2832. 4D Flow of the Whole Heart and Great Vessels at 3T Using Real Time Self Respiratory Gating Sergio Andres Uribe1, Philipp Beerbaum1, Allan Rasmusson2, Thomas Sangild Sørensen2, Reza Razavi1, Tobias Schaeffter1 1Kings College London, London, UK; 2University of Aarhus, Aarhus, Denmark

We present an extension of a self-respiratory technique to acquire 4D flow data. Self-navigation is obtained from k-space center profiles and the breathing signal is used in real time to gate the scan. The method allows us to acquire an isotropic non-angulated volume, 4D flow encoded, of the whole heart and great vessel in a single free-breathing scan. Results showed a strong correspondence between flow patterns obtained using this technique and with 2D flow. This approach represents an important advance for the characterization of the flow hemodynamics in the whole heart and a step forward to simplify cardiac MR examinations.

Vessel Compliance Hall D Monday 14:00-16:00

14:00 2833. A New Methodology for Determining Aortic Pulse Wave Velocity Using 2D PCMR Velocity Data Samuel Fielden1, 2, Brandon Fornwalt2, Michael Jerosch-Herold3, Robert Eisner1, Arthur Stillman1, John Oshinski1, 2 1Emory University, Atlanta, USA; 2Georgia Institute of Technology/Emory University, Atlanta, USA; 3Oregon Health & Science University, Portland, USA

A novel method for estimating aortic pulse wave velocity is presented. This method uses 2D PCMR data to construct blood velocity magnitude images in order to determine multiple flow waveforms in the ascending, transverse, and descending sections of aorta. The waveform at each location is compared to the most proximal waveform via cross correlation to determine the time delay of the wave at that location and thus the pulse wave velocity. This method is more reproducible than either of two more established methods examined.

14:30 2834. Measurement of Aortic Pulse Wave Velocity in Volunteers Neva Hiten Patel1, Mark Butlin2, Richard T. Black1, Martin J. Graves, 13, Stacey Hickson4, Carmel McEniery4, Ian B. Wilkinson4, David J. Lomas3 1Addenbrooke's Hospital NHS Trust, Cambridge, UK; 2Macquarie University, Sydney, Australia; 3University of Cambridge, UK; 4University of Cambridge, Cambridge, UK

Aortic pulse wave velocity (PWV) can be used as an index of the increased risk of cardiovascular disease which is associated with aortic wall stiffness. A number of groups have looked at measuring PWV using MRI, however we are not aware of any reported studies addressing the best method of obtaining the transit-time used to calculate the PWV, and the reproducibility of PWV measurement. We have performed repeated MRI PWV measurements in healthy volunteers and investigated several different methods of transit-time calculations.

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Poster Sessions

463

15:00 2835. The Effect of Wall Compliance on Aortic Hemodynamics in the Mouse: Implications for AAA Pathogenesis Smbat Amirbekian1, Robert C. Long1, Jin Suo2, W Robert Taylor1, 2, Don P. Giddens2, John N. Oshinski1, 2 1Emory University, Atlanta, Georgia, USA; 2Georgia Tech, Atlanta, Georgia, USA

MRA and PC-MRI were used to provide geometric and flow boundary conditions for a computational study of the hemodynamics of the mouse aorta. The study showed that incorporating vessel compliance changes the flow patterns seen in the aorta and that a rigid vessel creates areas of oscillatory wall shear stress.

15:30 2836. Measurement of Common Carotid Artery Lumen Dynamics During Cardiac Cycle Using TrueFISP Cine MR Imaging Tracy Yee Mau Chow1, 2, Jerry S. Cheung1, Yin Wu1, Ed X. Wu1 1The University of Hong Kong, Pokfulam, Hong Kong

Vascular MR imaging provides detailed anatomical information of blood vessels, yielding lumen size and wall thickness measurements. However, many of the studies often specify the morphology and composition of vessel walls without examining the dynamic pulsatile properties of these vessels. In this study, the vascular dynamics of the right and left common carotid arteries throughout the whole cardiac cycle was investigated using TrueFISP cine cardiac imaging. Consistent results and area waveform patterns were observed among the normal subjects. This lumen dynamics can better describe physiological behaviour correlated with other vascular parameters, therefore has potential clinical importance in differentiating abnormalities. Furthermore, TrueFISP cine MRI produces high contrast images, allowing high accuracy in area measurements and thus waveform tracing.

Myocardial T2 & T2* Imaging Hall D Monday 14:00-16:00

14:00 2837. Spiral T2 Quality Evaluation in Patients with Coronary Artery Disease Warren Foltz1, Kim Alexander Connelly1, Ram Vijayaraghavan1, Venkat Ramanan, Gideon Paul1, Graham Wright1, Alexander Dick1 1Sunnybrook Health Sciences Centre, Toronto, Canada

T2 has proven to be a valuable contrast mechanism for myocardial characterization because it is a quantitative biomarker of acute and sub-acute inflammatory processes. Clinical integration of T2 relies on T2-weighted black-blood fast-spin echo (FSE) imaging because cardiac-gated imaging is achievable in breath-hold scan times and with useful spatial resolutions. However the information is semi-qualitative and the echo-train readout compromises T2 contrast. A magnetization-prepared spiral imaging method, termed T2prep, should improve reproducibility in clinical quantification of myocardial T2 relaxation because variability associated with coil shading is removed. In the absence of gross relaxation fluctuations, current clinical myocardial FSE scanning is useful only to delineate cardiac margins. Quantitative T2prep mapping reduces variability towards physiological noise levels, providing more reproducible measurements with the potential for faster scan times at minor cost to spatial resolution and ROImin.

14:30 2838. Using T2*-Maps as a Quantitative Indicator for Myocarditis Karl-Heinz Herrmann1, Diane Renz1, Pascal Baltzer1, Ines Krumbein1, Jürgen R. Reichenbach1 1Friedrich-Schiller-University, Jena, Germany

Diagnosis of myocarditis with standard sequences like late enhancement, T2 TSE or T2-weighted TIRM is not always conclusive because any through plane motion of the myocardium causes inhomogeneous signal due to the repeated slice selective inversion and excitation pulses. A quantitative T2*-map may be helpful in quantifying, delineating and detecting edema associated with myocarditis.

15:00 2839. Retrospective Correction for Induced Magnetic Field Inhomogeneity in Measurements of Large-Vessel Hemoglobin Oxygen Saturation by MR Susceptometry Michael Langham1, Tom Floyd2, Jeremy Magland1, Felix W. Wehrli1 1University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA; 2Univesity of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA

The main source of error in MR susceptometry is the static field inhomogeneity that is characterized by low spatial-frequency modulation on the phase image. High-pass filtering has previously been used in conjunction with shimming. We propose an alternative method which acquires data without scanner-implemented default shimming, and fit, after appropriate weighting and masking, the static field inhomogeneity to a second-order polynomial. Compared to shimming, the retrospective correction technique improved agreement between hemoglobin saturations measured in different segments of a vessel (femoral versus popliteal artery and vein) from three standard errors to less than one.

15:30 2840. Multislice Multiecho T2* Cardiovascular Magnetic Resonance Can Detect Heterogeneous Myocardial Iron Distribution in Thalassemia Patients Vincenzo Positano1, Alessia Pepe1, Anna Ramazzotti1, Daniele De Marchi1, Brunella Favilli1, Eliana Cracolici2, Maria Gabriella Brizi3, Maria Filomena Santarelli1, Massimo Lombardi1, Luigi Landini4 1Institute of Clinical Physiology, Pisa, Italy; 2University of Palermo, Palermo, Italy; 3A. Gemelli University Hospital, Roma, Italy; 4University of Pisa, Pisa, Italy

In this study we investigate the relationship between segmental R2* heterogeneity assessed by multi-slice multi-echo MRI and iron overload progression in a large thalassemia major patient population. Real data were compared with a surrogate data sets obtained stating that the inhomogeneous segmental distribution of R2* would be generated by susceptibility artefacts. Inhomogeneities in R2* myocardial distribution in iron overloaded subjects cannot be explained by the effect of susceptibility artefacts, that are additive in the R2* domain and should vanish at high iron overload levels. A possible interpretation is that a true heterogeneity in iron overload distribution in TM patients exists.

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Vessel Wall imaging Hall D Monday 14:00-16:00

14:00 2841. An Optimized 3D Inversion Recovery Prepared Fast Spoiled Gradient Recalled Sequence with Multiple Echoes (IR FSPGR ME) for Carotid Plaque Imaging David C. Zhu1, J Kevin DeMarco1, Anthony T. Vu2 1Michigan State University, East Lansing, Michigan, USA; 2GE Healthcare, Waukesha, Wisconsin, USA

An optimized 3D inversion recovery prepared fast spoiled gradient recalled sequence with multiple echoes (IR FSPGR ME) on a 3T scanner for carotid plaque imaging is presented. It maintains the ability of its single-echo counterpart in blood and fat signal suppression at the carotid region as well as the benefits of high-resolution volumetric visualization and hemorrhage detection. The IR FSPGR ME sequence can potentially further characterizes hemorrhage types through the generated T2* maps. In addition, combining images from the individual echoes provides a higher signal-to-noise ratio and thus improve image visualization.

14:30 2842. Optimization of Motion Sensitized Driven Equilibrium (MSDE) Preparation Scheme for Multi Contrast 3D Vessel Wall Imaging at 3.0T Makoto Obara1, 2, Masatoshi Honda3, Rie Nozaki2, Marc Van Cauteren1, Kagayaki Kuroda2 1Philips Medical Systems, Minato-ku, Japan; 2Tokai University, Hiratsuka-shi, Japan; 3Tokai University Hospital, Isehara-shi, Japan

3D turbo field echo (TFE) sequence prepared by motion sensitized driven equilibrium (3D-MSDE-TFE) was optimized for T1W and T2W carotid artery wall imaging and compared to the conventional 2D double inversion recovery (DIR) turbo spin echo (TSE). T1 and T2 contrasts of 3D-MSDE-TFE were controlled by adjusting the MSDE preparation time, shot interval and acquisition flip angle. MSDE optimization was achieved by changing the number of refocusing pulses from 1 to 4 using MLEV scheme. Achieved T1 and T2 contrasts of the optimized 3D-MSDE-TFE were similar to those of conventional 2D-DIR while scan time was 2 times faster. Therefore, this approach may be appropriate for vessel wall screening.

15:00 2843. Evaluation of the Relationship Between the Superficial Calcification and Intraplaque Hemorrhage in the Atherosclerotic Carotid Plaque by 3T High Resolution MRI Haiyue Ju1, Xian Xu1, Lin Ma1, Zulong Cai1, Youquan Cai1, Xinjiang Wang1, Jianming Cai1 1Chinese PLA General Hospital, Beijing, People's Republic of China

We aim to evaluate the relationship between the shape and location of superficial calcification and intraplaque hemorrhage in the atherosclerotic carotid plaque. One hundred and eighty three slices with superficial calcification in 51 patients were enrolled in this study. All the patients underwent 3T MRI examination with a contrast-enhanced multi-contrast weighted protocol. This study showed that the nodular type of superficial calcification in the atherosclerotic carotid plague has higher possibility of simultaneous occurrence with intraplaque hemorrhage than that of patchy type, whereas, in hemorrhage group, the percentage of either marginal or central type of superficial calcification is not significantly different from that in non-hemorrhage group.

15:30 2844. Gadolinium Contrast Enhancement of Carotid Atherosclerotic Plaque is Associated with Symptomatic Status Jianming Cai1, Niranjan Balu2, Dongxiang Xu2, Haiyue Ju1, Xian Xu1, Xihai Zhao1, Chun Yuan2 1Chinese PLA General Hospital, Beijing, People's Republic of China; 2University of Washington, Seattle, USA

Symptomatic carotid atherosclerosis is known to be associated with plaque neovasculature and inflammation. An increase in vasa vasorum accompanies the increased inflammation and plaque neovasculature of advanced atheorsclerosis. The increased blood supply from the vasa vasorum plexus surrounding the carotid artery may be reflected in contrast enhancement (CE) patterns of the outerwall. The association between outerwall CE on black-blood contrast-enhanced MRI (CE-MRI) and symptomatic status was investigated in 24 patients. Outerwall CE was clearly visualized by CE-MRI. Symptomatic status was found to be associated with a more homogenous outerwall CE compared to asymptomatic arteries.

14:00 2845. DSCT and 3T MR for Characterization of Carotid Plaque in Patients John J. Sheehan1, Natasha Berg2, Timothy Carroll2, Peter J. Weale3, Renate Jerecic3, James C. Carr2 1Northwestern University, Chicago, Ireland; 2Northwestern University, Chicago, Illinois, USA; 3Siemens Medical Solutions, Chicago, Illinois, USA

Atherosclerotic disease is a significant cause of morbidity and mortality. Recent studies have suggested that plaque composition is an important prognostic factor and may be more predictive of adverse outcomes than overall degree of stenosis. Previous studies have attempted to characterize carotid plaque components using various imaging modalities. In this small patient study, we looked at the relative efficacy of two new technologies, 3 Tesla (3T) MR and Dual Source CT (DSCT) to evaluate plaque components. We hypothesized that these modalities could provide improved depiction of plaque components, which may have important diagnostic and therapeutic implications.

14:30 2846. Single-Shot DENSE MRI of the Carotid Arteries Alexander Peter Lin1, 2, Eric Bennett2, Yuan Le2, Scott Fraser1, Han Wen2 1California Institute of Technology, Pasadena, California , USA; 2National Institutes of Health, Bethesda, Maryland, USA

DENSE strain mapping of the carotid artery wall systolic distension provides regional stiffness measures. However, the scan lasts several minutes, and segmented k-space acquisition suffers from artifacts due to head-neck motion and turbulent in-plane blood flow. This problem is solved with a single-shot imaging sequence and rigid body image registration in postprocessing.

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15:00 2847. MRI-Based Biomechanical Imaging: Role of Hemodynamic Forces on the Early Plaque Remodeling Jie Zheng1, Dana Abendschein1, Ruth J. Okamoto2, Deshan Yang1, Kyle McCommis1, Bernd Misselwitz3, Robert J. Gropler1, Dalin Tang4 1Washington University School of Medicine, Saint Louis, USA; 2Washinton University, Saint Louis, USA; 3Bayler Schering Pharma AG, Berlin, Germany; 4Worcester Polytechnic Institute, Worcester, Massachusetts, USA

Local hemodynamic forces play important roles in the regulation of early atherosclerosis progression and vessel remodeling. A MRI-based biomechanical imaging technique was developed and evaluated in vivo in a porcine atherosclerotic plaque model. A plaque targeted contrast-enhanced MR images provided plaque structure for the computational modeling in this technique. Progression and regression of the early plaques were observed and flow shear stress show consistent findings with other reports. Furthermore, structures stress and strain also demonstrated strong correlations with plaque progression and regression, indicating multi-factors of hemodynamic effect to the early atherogenesis.

15:30 2848. Characterization of Ex Vivo Carotid Plaque with 3T MRI: A Comparison with Histology Natasha Berg1, John Joseph Sheehan1, Peter J. Weale2, Mark Morasch1, Nicole Mascheri1, James C. Carr1, Timothy Carroll1 1Northwestern University, Chicago, Illinois, USA; 2Siemens Medical Solutions, Chicago, Illinois, USA

Atherosclerotic disease of the carotid artery is a significant cause of morbidity and mortality. Previous imaging techniques have focused on quantifying stenosis in the vessel, but recent research suggests that composition of plaque may be a more important prognostic factor. Ex vivo studies of carotid plaques have attempted to characterize plaque using 1.5 T MR and have shown that 2D PDW, T1W and T2W sequences on MRI may have some utility in demonstrating areas of fibrous matrix and necrotic core. Here, we perform an intial evaluation of 3T MRI in the characterization of ex-vivo carotid plaque specimens.

14:00 2849. High-Resolution Multi-Contrast MRI Characterization of Rabbit Atherosclerosis Using Clinical Pulse Sequences Andre Jean-Louis Belisle1, 2, John A. Ronald, 12, Kem A. Rogers1, Brian K. Rutt, 12 1University of Western Ontario, London, Canada; 2Robarts Research Institute, London, Canada

We used multi-contrast ex vivo 3T MRI of aortic specimens from defined regions of a low-level long-term cholesterol-fed rabbit model of atherosclerosis. The objective was to collect high-resolution images using clinically available pulse sequences to resolve the structural components of plaques and to provide histological verification. The most complex regions of plaque appear to be in the descending aortic arch which was demonstrated by all sequences and is especially evident when compared to T2w controls. Eventually this research could be used for visualizing the vulnerable plaque and direct further in vivo research by specifying imaging target regions in the aorta.

14:30 2850. In Vivo & Ex Vivo Micro-MRI in Detection of Mouse Atherosclerotic Plaques: An MRI-Histopathology Correlation Study Daohai Xie1, 2, Bensheng Qiu1, Jiangyang Zhang3, Xiaoming Yang1 1University of Washington, Seattle, Washington, USA; 2Suzhou University School of Medicine, Suzhou, People's Republic of China; 3Johns Hopkins University School of Medicine, Baltimore, Maryland, USA

Atherosclerotic cardiovascular disease remains the leading cause of death in the developed countries. Continuous efforts are warranted to understand more about the pathogenesis and management of atherosclerotic cardiovascular disease. High-field micro-MR technology offers both high spatial resolution and whole-body coverage. This study focused on evaluation of capability using in vivo and ex vivo micro-MRI to detect mouse atherosclerotic plaques, which was correlated with histopathology. The results of the current study may encourage the continued efforts to develop high-field MR imaging techniques to characterize atherosclerotic plaques in vivo, so-called ¡ in-vivo plaque pathology,¡± which should become an essential imaging tool for early diagnosis and efficient treatment of atherosclerotic cardiovascular disease.

15:00 2851. In Vivo MRI and MRA Assessment of Patency in a Novel Model of Vascular Remodelling Using Patent Aortic Grafts King Kenneth Cheung1, 2, Andrew R. Thompson3, H Hafez4, Andrew M. Taylor2, Roger J. Ordidge1, Stephen E. Humphries3, Mark F. Lythgoe2 1University College London (UCL), London, UK; 2UCL, London, UK; 3Royal Free & University College London Medical School, London, UK; 4St Richards Hospital, Chichester, UK

Fibulin-5 (fbln-5) is an extracellular matrix protein that is central to elastic fibre maturation and vessel development. A novel model has been devised to investigate the role of fbln-5 in vascular remodelling in a patent vessel. As sustained graft patency is central to this model, we evaluated the accuracy of MRI and MRA for determining graft patency in vivo. MRI and MRA correctly identified all patent (n=8) and non-patent (n=3) grafts. The non-invasive and robust nature of MRI and MRA offers an excellent alternative to traditional assessment through repeated invasive surgery, thus improving survival and reducing animal usage.

15:30 2852. Characterisation of Vascular Injury Responses Following Balloon Injury of the Rat Carotid Artery Using Combined in Vivo Imaging and ex Vivo Microscopy King Kenneth Cheung*1, 2, Manfred Junemann-Ramirez*2, Pauliina Lehtolainen2, Alan Rudiger2, Mark Turmaine, David Sanz2, Roger J. Ordidge1, John F. Martin2, Mark F. Lythgoe2 1University College London (UCL), London, UK; 2UCL, London, UK

The vascular endothelium is crucial in regulating biological functions such as haemostasis. However this layer is often impaired in cardiovascular diseases. Understanding the evolution of vascular remodelling is therefore of great importance and may provide insights for the development of novel interventions. Here we present the use of in vivo MRI and vascular ultrasound in combination with ex vivo electron microscopy for extensive characterisation of the events involved in vascular remodelling following balloon angioplasty of the rat carotid artery over a 28 day follow-up period.

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14:00 2853. New Insights Into Ruptured Plaques: Enhanced Detection of Neovasculature and Fibrous Tissue by MRI Alkystis Phinikaridou1, Kevin J. Hallock1, Ye Qiao1, James A. Hamilton1 1Boston University, Boston, Massachusetts, USA

We used the Constantinides New Zealand White rabbit model to study atherosclerosis and controlled plaque rupture associated with thrombosis. We combined contrast enhanced (Gd-DTPA) in vivo (3T) and magnetization transfer (MT) ex vivo (11.7T) MRI coupled to histology to identify features associated with vulnerable plaques. In vivo, Gd-DTPA uptake was associated with plaque regions rich in neovasculature as well as fibrous tissue. Ex vivo MT identified the location of fibrous cap rupture and fibrosis seen within organized thrombi. Further studies about the kinetics of Gd-DTPA within plaques together with the in vivo application of MT will provide insights about plaque vulnerability.

14:30 2854. Enhancement of the Atherosclerotic Plaque and the Vessel Wall of the Carotid Artery After Injection of a Blood-Pool Contrast Agent Sietske Rozie1, Piotr A. Wielopolski1, Mohamed Ouhlous1, Wiro Niessen, Theo van Walsum, Aad van der Lugt1 1Erasmus Medical Center, Rotterdam, Netherlands

Purpose: We hypothesized that a blood-pool agent enhances the outer wall of the carotid artery and specific parts of the atherosclerotic carotid plaqueMethods: We studied 26 atherosclerotic plaques of 15 consecutive patients with severe carotid stenosis. On a 3.0T scanner a 3DT1-weighted scan was performed before injection and 20 minutes after injection.Results: The mean enhancement on the 20 minute delay scan was 40.9% ± 32.5% in the non-calcified part of the plaque and 60.0% ± 21.7% in the vessel wall of the symptomatic carotid arteries. Conclusions: Images obtained before and after contrast injection with Vasovist® may improve atherosclerotic plaque characterisation and quantification.

15:00 2855. In Vivo and ex Vivo plaque Characterisation in the Aortic Arch of ApoE -/- Mice with High-Resolution Multi-Parametric Magnetic Resonance Imaging at 17.6 Tesla Gert Klug1, Volker Herold1, Marco Parczyk1, Elisabeth Bauer1, Thomas Schulze-Till1, Eberhard Rommel1, Peter Jakob1, Wolfgang Bauer1 1University of Wuerzburg, Wuerzburg, Germany

High-Resolution plaque imaging in atherosclerotic apoE knock-out (-/-) mice has been recently shown to correlate closely with histology. However these results are limited to the aortic-root. We intended to further enhance the ability of high-field magnetic resonance (MR) to characterize plaque formation in murine models of atherosclerosis at microscopic levels. Our results demonstrate that high resolution multi-parametric plaque imaging at 17.6 Tesla is feasible with good correlation to HE histology but further studies are necessary to distinguish plaque components compared to a more comprehensive histology protocol.

15:30 2856. Molecular Imaging of Atherosclerosis Using Paramagnetic Cy5.5-Labeled PEG-Micelles Sjoerd Hak1, Geralda A.F. van Tilborg1, Esad Vucice2, Gustav J. Strijkers1, Klaas Nicolay1, Zahi A. Fayad2, Willem Jan Menno Mulder2 1Eindhoven University of Technology, Eindhoven, Netherlands; 2Mount Sinai School of Medicine, New York, New York, USA

In this study a new contrast agent for molecular imaging of atherosclerosis was used, paramagnetic Cy5.5-labeled PEG-micelles. The targeting ligand used was the RGD-peptide. In vivo MRI and ex vivo fluorescence techniques demonstrated active uptake of RGD-PEG-micelles into atherosclerotic plaque in apoE-knockout mice. The near infrared Cy5.5 fluorophore proofed to be very valuable for ex vivo fluorescence imaging as there is less autofluorescence and better penetration at higher wavelengths. The non-specific uptake of bare PEG-micelles in mouse plaques was very limited. This makes this contrast agent very attractive for molecular imaging of atherosclerosis, also when directed to other targets.

Cardiac Image Processing Hall D Tuesday 13:30-15:30

13:30 2857. Real-Time Cardiovascular Imaging Using a Combination of HYPR, McKinnon-Bates, and COM Gating Algorithms Lauren A. Keith1, Dana C. Peters, Julia V. Velikina1 1University of Wisconsin - Madison, Madison, Wisconsin, USA

We use a combination of the HYPR and McKinnon-Bates algorithms along with center of mass self-gating in order to improve spatial resolution, signal-to-noise ratio and reduce artifact levels in real-time cardiovascular imaging.

14:00 2858. Characteristics and Performance of the Karhunen-Loeve Transform Filter in Dynamic Cardiac Magnetic Resonance Imaging Yu Ding1, Yiu-Cho Chung2, Subha V. Raman3, Orlando P. Simonetti3 1The Ohio State University, Columbus, Ohio, USA; 2Siemens Medical Solutions, Inc., Columbus, Ohio, USA; 3The Ohio State University, Columbus, Ohio, USA

We describe the characteristics and performance of a new temporal filter based on the optimal linear transform, the Karhunen-Loeve Transform. The filter is designed to suppress noise in dynamic cardiac MR images without compromising the sharpness of stationary or moving edges or other structures. We derive a simple mathematical formula for the noise reduction effect of this filter, and then verify it in real-time cardiac cine MRI with TSENSE acceleration factor 4 in normal volunteers. A SNR gain of 144% was achieved after filtering without edge blurring or other artifacts.

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14:30 2859. Dyadic Wavelet-Based Image Noise Suppression and Enhancement in High-Speed Cardiac MR Parallel Acquisition Qi Duan1, Jian Chen1, Andrew Francis Laine1, Vinay M. Pai2 1Columbia University, New York, New York, USA; 2SUNY Upstate Medical University, Syracuse, New York, USA

An automated integrated denoising/enhancing approach was applied to images acquired by parallel acquisition techniques in cardiac imaging. In comparison with previous denoising only framework, this new proposed method could future increase the CNR of the denoised images. Quantitative evaluation on phantom and clinical data confirmed the benefit of this new method in terms of improving CNR on parallel MR images. Preliminary results suggested that this new integrated denoising/enhancing framework could further push the limits on the temporal resolution by improving the SNR and CNR simultaneously.

15:00 2860. 3D Right Ventricular Strain and Geometry in Pulmonary Hypertension and Normals Bharath Ambale1, Steven Lloyd2, Thomas Stewart Denney Jr. 1, Louis Dell'Italia2, Raymond Benza2, Himanshu Gupta2 1Auburn University, Auburn, Alabama, USA; 2University of Alabama at Birmingham, Birmingham, Alabama, USA

Accurate assessment of right ventricular (RV) function is clinically important – particularly in pulmonary hypertension (PHTN). Compared to the left ventricle (LV), however, analysis of RV function is relatively difficult. Unlike the LV, the RV does not have geometric symmetry, precluding use of simple geometric models to calculate RV volumes and wall stress. Also, in PHTN, higher systolic blood pressure in the RV can cause excursion of the interventricular septum into the LV cavity. As a result, the LV cavity can also lose its geometric symmetry. This abstract presents methods for reconstructing three-dimensional biventricular geometry and strain in both normal volunteers and PTN patients.

13:30 2861. Direct Quantification of 3-D Myocardial Principal Strain Orientations: A New Insight Into Heart Regional Function Abnormality Khaled Zakarya Abd-Elmoniem1, Matthias Stuber1, Amr A. Youssef1, Tetsuo Sasano1, Theodore P. Abraham1, Xiaofeng Lui1, Sandeep Mullur1, Evert-Jan P. A. Vonken1, M. Roselle Abraham1, Jerry L. Prince1 1The Johns Hopkins University, Baltimore, Maryland, USA

We present afast algorithm for direct and complete characterization of 3-D time-course of principle strain orientations using data acquired with zHARP imaging protocol from SA slices without the need for LA data. Using this scheme, two or more SA slices are acquired and processed using zHARP and the 3-D strain tensor and principal strain angles are calculated. Results from infarct swine model shows that strain orientations time-course can provide more information about heart dynamics, especially when combined with efficient 3-D motion imaging.

14:00 2862. Quantification of Myocardial Strain at Early Systole in Mouse Heart: Restoration of Undeformed Tagging Grid with Single Point HARP Wei Li1, Jia Zhong2, Xin Yu2 1Case Western Reserve University, Cleveland , Ohio, USA; 2Case Western Reserve University, Cleveland, Ohio, USA

Current MRI tagging analysis often employs the first tagging image as the reference frame. However, for a mouse heart, the first tagging image is frequently acquired at early systole with significant tag line deformation due to fast heart rate. In this study, a HARP-based method was develop to generate an undeformed tagging grids. Myocardial deformation at early systole was analyzed using this method.

14:30 2863. Noise Measurement in Real-Time Cardiac Cine MRI Using Eigenvalues of Karhunen-Loeve Transform Yu Ding1, Yiu-Cho Chung2, Subha V. Raman3, Orlando P. Simonetti3 1The Ohio State University, Columbus, Ohio, USA; 2Siemens Medical Solutions, Inc., Columbus, Ohio, USA; 3The Ohio State University, Columbus, Ohio, USA

Noise measurement is difficult in real-time cine MRI using parallel acquisition techniques because of cardiac and respiratory motion and the spatially variant nature of both signal and noise. In this work, we investigate using eigenvalues derived from the Karhunen-Loeve Transform to assess mean noise standard deviation in dynamic MR cardiac images. This method may have general application in the evaluation of dynamic imaging methods, and other situations other methods of noise measurement are difficult to apply.

15:00 2864. DENSE-MR-Elastography for Cardiac Application Benjamin Robert1, Ralph Sinkus1, Jean-Luc Gennisson1, Mathias Fink1 1Laboratoire Ondes et Acoustique, Paris, France

Imaging of mechanical shear waves via MR-Elastography (MRE) allows the assessment of inherent viscoelastic tissue parameters. Cardiac MRE poses several technical challenges: small relaxation times, time dependant viscoelastic properties during the heart beat, respiratory motion. To overcome the short relaxation time and the externally induced mechanical wave problems, a MRE sequence has been adapted from a DENSE sequence.

MRA -Other Techniques Hall D Tuesday 13:30-15:30

13:30 2865. Increased Volume of Coverage for Abdominal Contrast-Enhanced MRA with 2D Autocalibrating Parallel Imaging: Initial Experience at 3.0T Darren Lum1, Reed Busse2, Christopher Francois1, Anja Brau3, Philip Beatty3, Joshua Huff1, Jean Brittain2, Scott Reeder1 1University of Wisconsin - Madison, Madison, Wisconsin, USA; 2GE Healthcare, Madison, Wisconsin, USA; 3GE Healthcare, Menlo Park, California , USA

We utilize a 2D parallel imaging method (Autocalibrating Reconstruction for Cartesian sampling - ARC) with 3D contrast enhanced MRA for complete abdominal coverage within a breath hold. An intra-individual comparison study between both parallel imaging accelerated and non-accelerated exams was performed in 6 healthy volunteers. In addition 8 consecutive patients were evaluated with 2D-ARC MRA. We find that the subjective image quality of exams with 2D-ARC to be essentially equivalent to those acquired without parallel imaging. However, the 2D-ARC sequence provided a 3.5 fold increase in imaging volume and a 30% reduction in voxel size in the same acquisition time.

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14:00 2866. Whole-Body MR Angiography with Parallel Imaging – Benefit of a Dedicated 32 Channel Whole-Body MR Scanner Equipped with a Matrix Coil System at 1.5 and 3.0 Tesla Harald Kramer1, Konstantin Nikolaou1, Henrik J. Michaely2, Christian Glaser1, Maximilian F. Reiser1 1University Hospitals Munich - Grosshadern Campus, Munich, Germany; 2University Hospital Mannheim, Mannheim, Germany

Atherosclerosis is a systemic vessel disease. MRI offers the possibility of whole body MRA with excellent image quality and without ionizing radiation. First attempts to WB MRA suffered from MR system Hardware restrictions, recent developments in MR Hard- and Software like parallel imaging, dedicated coil systems and higher field strength helped to increase image quality of WB MRA exams significantly.

14:30 2867. Comparison of Scoutless EZ-STEP and Conventional Contrast Enhanced Magnetic Resonance Angiography in Thoracic Aorta at 3T Xiaohai Ma1, 2, Zhaoqi Zhang1, Yi He1, Zhanming Fan1 1Beijing Anzhen Hospital, Beijing, People's Republic of China; 2Michigan State University, East Lansing, USA

Compared to conventional CE-MRA, EZ-STEP is a timesaving method for thoracic aorta imaging in 3T MR scanner, and also provides comparable image quality.

15:00 2868. Calculating Peripheral MRA Bolus Timing Using Cine-Phase Contrast Flow Measurements Grace Choi1, Ryan Brown1, Minh Chao1, Yi Wang1, Martin R. Prince1 1Cornell University - Weill Cornell Medical College, New York, USA

Total Gadolinium dose can be reduced on whole body and peripheral MRA by using 2D cine phase contrast MRA to calculate bolus velocity at 7 locations along the arterial tree. Accuracy of this approach was confirmed by comparison to bolus transit measurements from 1.8s temporal resolution time-resolved MRA. Example cases show diagnostic peripheral MRA with single dose gadolinium based contrast agent. These data also show a 2-fold reduction in bolus transit time with venous compression applied to thighs.

Time-resolved (YD) MRA Hall D Tuesday 13:30-15:30

13:30 2869. High Spatial and Temporal Resolution MRA of the Entire Peripheral Vascular System Using a New 3D Time-Resolved MRA Technique (TWIST) Florian M. Vogt1, Stefan Maderwald1, Knut Kroeger1, Gerhard Laub2, Randall Kroeker3, Joerg Barkhausen1, Harald H. Quick1 1University Hospital, Essen, Germany; 2University of California Los Angeles, Los Angeles, California , USA; 3Siemens Medical Solutions, USA

Purpose was to develop a triple injection scan protocol for dynamic, high-resolution, isotropic MRA of the entire peripheral vascular system applying a recently developed time-resolved 3D MRA sequence (TWIST). Ten patients with PAD underwent contrast-enhanced MRA collecting dynamic 3D data sets at three consecutive stations. Catheter-based DSA served as standard of reference. For corresponding segments, the number of visible segments was equal to DSA. TWIST MRA provided identical functional information in regions with reduced arterial blood flow or increased venous enhancement. TWIST-MRA is a robust technique that combines functional with high spatial morphological information of the entire peripheral vascular system.

14:00 2870. Leg MR Angiography with Cuff-Compression: Quantitative Dynamic Analysis Marcel Koenigkam Santos1, Puneet Sharma1, Bobby Kalb1, John Oshinski1, Diego Martin1 1Emory University, Atlanta, USA

The purpose of this study is to evaluate quantitatively the effect of mid-femoral cuff compression on arterial inflow and venous outflow kinetics using high temporal resolution 3D CE-MRA of the calves. The arterial in-flow time was significantly reduced on the pressure cuff side in comparison to the control side and, in 2 of 4 subjects, no increased signal (above background) was observed in the veins with the pressure cuff after 300 seconds. Our findings quantitatively evaluate the delay in venous filling and indirectly show that this results from multi-factorial events that occur subsequent to supravenous-subarterial blood pressure cuff inflation.

14:30 2871. Cartesian Acquisition with Projection-Reconstruction-Like Sampling (CAPR): An Optimum Sequence for Time-Resolved CE-MRA Clifton R. Haider1, Houchun Harry Hu2, Nobert G. Campeau1, John Huston1, Stephen J. Riederer1 1Mayo Clinic, Rochester, Minnesota, USA; 2Univ. of Southern California, California , USA

In time-resolved acquisitions there is a need for both high temporal and spatial resolution. The purpose of this work is to describe the incorporation of 2D SENSE acceleration into a view-shared CArtesian Projection Reconstruction-like (CAPR) acquisition, yielding a time-resolved sequence which has high SNR robustness, a high level of consistency, and high temporal fidelity. The sequence is capable of 1 mm3 isotropic resolution with sufficient temporal resolution to distinguish intracranial arterial and venous phases of contrast passage in whole-brain angiography.

15:00 2872. Comprehensive Magnetic Resonance Imaging of Hands Vasculature at 3 Tesla: Preliminary Clinical Results Ugur Bozlar1, 2, Patrick T. Norton1, Ahmed Mohamed Housseini1, 3, Thomas Huerta1, Hendricks E. Daniel1, Bobby Chhabra1, David B. Drake1, Peter B. Arnold1, Klaus D. Hagspiel1 1University of Virginia Health System, Charlottesville, USA; 2Gulhane Military Medical Academy, Ankara, Turkey; 3Suez Canal University, Ismailia , Egypt

Comprehensive MR evaluation of the vasculature of the hand employing high resolution time resolved contrast enhance MRA (tr-ceMRA) and volume interpolated breath-hold examination (VIBE) was performed in patients with clinical symptoms attributable to vascular etiologies. This combine complimentary approach requires a single 20ml administration of contrast agent and utilizes the power of arterial-venous separation provided by the tr-ceMRA and high contrast to noise ratio of the VIBE sequence to allow for assessment of both proximal and distal arterial vessels of the hand. To the best of our knowledge, there is no published study which evaluates the hand vasculature at 3T in such a population.

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13:30 2873. 4D Dynamic Contrast Enhanced MRA of the Pulmonary Vasculature with Isotropic Resolution Using a Combination of GRAPPA and TWIST Acceleration Robert C. Gilkeson1, 2, Martin Blaimer3, Randall Kroeker4, Gerhard Laub4, Jeffrey L. Duerk1, 2, Jeffrey L. Sunshine1, 2, Robert O. Schilz2, Mark A. Griswold1, 2 1Case Western Reserve University, Cleveland, Ohio, USA; 2University Hopitals of Cleveland, Cleveland, Ohio, USA; 3University of Wuerzburg, Wuerzburg, Germany; 4Siemens Medical Solutions, Germany dwdw wd w

14:00 2874. Time-Resolved 3D MR-Angiography of the Thoracic Aorta at 3 Tesla: Comparison of First-Pass Imaging Characteristics of a Low Albumin-Binding and a Blood-Pool Contrast Agent Alex Frydrychowicz1, Maximilian F. Russe1, Aurélien F. Stalder1, Alexander Berger1, Andreas Harloff1, Raoul Arnold1, Mathias Langer1, Jürgen Hennig1, Michael Markl1 1University Hospital Freiburg, Freiburg, Germany

Gadofosveset trisodium has reached approval for diagnostic purposes in Europe as the first gadolinium-based blood-pool contrast agent. Its imaging characteristics have not been fully evaluated with respect to imaging at 3T and during time-resolved 3D MR-angiography. Therefore, it was the purpose of this study to compare the first-pass imaging characteristics of a blood-pool contrast agent (BPA) to a low albumin-binding standard contrast agent (SCA) in time-resolved contrast-enhanced 3-dimensional MR angiography (tr-CE-MRA) at 3T. Results show that first-pass imaging characteristics of the blood-pool agent are equally well suited for tr-CE-MRA at 3T.

14:30 2875. Contrast-Enhanced MR Angiography Using Time-Resolved Interleaved Projection Sampling Along the 3D Cartesian Phase and Slice Encodings (TRIPPS) Jiang Du1, Nick Pinto1, Michael S. Middleton1, Claude Sirlin1, Graeme M. Bydder1 1University of California, San Diego, San Diego, California , USA

Contrast-enhanced three-dimensional (3D) magnetic resonance angiography (CE-MRA) is a useful noninvasive method for evaluating the vascular system. Time-resolved imaging is of great importance in providing contrast dynamics and eliminating contrast timing. Here we present a novel technique called time-resolved interleaved projection sampling along the 3D Cartesian phase and slice encodings (TRIPPS), which is robust and provides high spatial and temporal resolution 3D images with minimal undersampling artifact.

15:00 2876. The Effect of Time-Resolved K-Space Sampling on Contrast-Enhanced MRA: A Method to Optimize Imaging Parameters Ting Song1, Pippa Storey2, Qun Chen2, Henry Rusinek2, Ruth Lim2, Andrew F. Laine1, Vivian S. Lee2 1Columbia University, New York, New York, USA; 2NYU School of Medicine, New York, New York, USA

We have analyzed k-space sampling strategies for time-resolved MRA by studying the effects of varying (a) the center area of k-space assumed to be fully sampled and (b) the sampling density of k-space periphery. Outcome measures consist of vessel ringing artifacts and diameter measurement accuracy. Overall, we observed that for smaller vessels, higher sampling density of k-space periphery is more important than the size of the fully sampled center area, while for larger vessels, larger center areas gave better accuracy of diameter resolving ability.

13:30 2877. Controlled Experimental Study Depicting Moving Objects in View-Shared Time-Resolved 3D MRA Petrice Marie Mostardi1, Clifton R. Haider1, Phil J. Rossman1, Stephen J. Riederer1 1Mayo Clinic, Rochester, Minnesota, USA

The purpose of this work was to develop and use a computer-controlled motion phantom for study of the fidelity with which 3D time-resolved sequences with view-sharing can portray dynamic phenomena. This allowed determination not only of such properties as ghosting, blurring, and undesired vascular enhancement, but also the fidelity of portraying a rapid influx of contrast into a vessel as well as the smooth passage of contrast across an extended field of view. These studies helped to identify desirable characteristics of a pulse sequence used for time-resolved studies.

14:00 2878. Three-Dimensional Time-Resolved Flow Quantification with Balanced SSFP Francesco Santini1, Stephan G. Wetzel2, Klaus Scheffler1 1University of Basel/University Hospital, Basel, Switzerland; 2Basel University Hospital, Basel, Switzerland

Balanced SSFP sequences do not suffer from spin saturation effects that result in signal loss for tissues with long T1. Their contrast is therefore optimal for the imaging of fluids (blood and CSF) and flow quantification, especially when inflow enhancement effects cannot be exploited, as in three-dimensional sequences. In this work, a three-dimensional, three-directional time-resolved phase contrast bSSFP sequence is presented, along with methods to minimize the artifacts commonly associated with bSSFP sequences, and the application to the study of cerebro-spinal fluid circulation is demonstrated.

14:30 2879. Femoral Artery Compression in the Adductor Canal During Isometric Thigh Contraction Using a Rapid 3D Steady-State Free Precession Acquisition Ryan Brown1, 2, Thanh Nguyen1, Martin R. Prince1, Yi Wang1, 2 1Weill Medical College of Cornell University, New York, USA; 2Weill Graduate School of Medical Sciences of Cornell University, New York, USA

A rapid 3D steady-state free precession (SSFP) sequence was implemented to image the femoral artery. A long section (15-20 cm) of artery was imaged during isometric thigh contraction to analyze artery compression. Sufficient resolution and contrast to visualize the artery lumen were achieved in a short scan time (approximately 22 sec), which was required for minimal motion artifacts during thigh contraction. Significant artery compression was observed in the adductor canal region, while the artery was less disturbed inferior and superior to the adductor canal.

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15:00 2880. Quantification of Hemodynamics in Abdominal Aortic Aneurysms During Rest and Exercise Using Magnetic Resonance Imaging and Computational Fluid Dynamics Andrea Seba Les1, Carlos Alberto Figueroa1, Mary Therese Draney Blomme1, Maureen M. Tedesco1, Jinha M. Park1, Adrianne Thompson1, Ronald L. Dalman1, Robert J. Herfkens1, Charles A. Taylor1 1Stanford University, Stanford, California , USA

We hypothesize that exercise may slow the growth of abdominal aortic aneurysms (AAAs). A gadolinium-enhanced magnetic resonance angiography sequence (MRA) was used to image the aortas of three males with small AAAs using a 1.5T scanner. Infrarenal and supraceliac aortic blood velocities were also measured using a cardiac-gated phase contrast (PC-MRI) sequence. Blood flow was simulated by solving the Navier-Stokes equations on finite-element meshes generated from the MRA and using rest and exercise boundary conditions specified from the PC-MRI data. Mean wall shear stress was calculated at four locations. Infrarenal volumetric flow waveforms obtained from simulation and PC-MRI were compared.

Animal Cardiovascular Imaging Hall D Tuesday 13:30-15:30

13:30 2881. Multiple-Mouse Self-Gated Cardiac Cine MRI with Multiple Arrays of Receive Coils (MARCs) Emilio Esparza-Coss1, Marc Stephen Ramirez1, James Andrew Bankson1 1The University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA

Simultaneous multiple-animal, self-gated cardiac cine MRI has been shown to drastically improve the imaging efficiency in small animal models of cardiac disease. Here we propose that further improvements can be achieved by dedicating a phased-array coil to each animal to increased SNR and achieve parallel imaging acceleration. Self-gated cardiac cine data was acquired with a four-channel spoiled gradient echo pulse sequence developed to acquire navigator information before application of readout gradients. Preliminary results indicate that accelerated self-gated cardiac cine MRI using phased-array coils is both feasible and desirable since SNR enhancement can be achieved by averaging oversampled data.

14:00 2882. Microembolization Contributes to Acute and Subacute Left Ventricular Dysfunction: MR Assessment of Left Ventricular Function and Strain Marcus Carlsson1, Alastair J. Martin1, Mark Wilson1, Loi Do1, David Saloner1, Maythem Saeed1 1University of California San Francisco, San Francisco, California , USA

Microembolization causes microinfarction in patients with unstable angina pectoris and following PCI and CABG. It thought to explain part of decreased ejection fraction in patients. In this study, microembolization was simulated by selective injection of embolic agents in LAD. Cine and tagging MR imaging was used to assess the acute and subacute effects of microembolization on LV volumes, ejection fraction, systolic wall thickening and strain. Cine MRI showed persistent decline in wall thickening and strain associated with increased LV volumes and decreased EF; markers of LV remodeling. Thus, microembolization could be the cause of LV dysfunction in patients.

14:30 2883. Self-Gated MR Cardiac Imaging of Developing Chick Embryos in the Egg William Matthew Holmes1, Christopher McCabe1, Barrie Condon1, Jim M. Mullin1, Maureen M. Bain1 1University of Glasgow, Glasgow, UK

The chick embryo is a well-known animal model for cardiovascular research. The lack of MRI application to chick embryos is partly due to the difficultly of monitoring chick ECG and respiration signals, which are conventionally essential in acquiring images free of motion artefact. In this study we remove these obstacles by employing a self-gated multi-slice CINE MRI protocol that incorporates a navigator-based retrospective gating technique, making possible for the first time cardiac MRI images of a chick embryo inside the egg.

15:00 2884. Retrospective Gating Strategies for Small Animal MR Imaging at 9.4 Tesla S David Smith1, 2, Shams Rashid3, Mark Wagshul3, Mei Yu1, Helene Benveniste1, 3 1Brookhaven National Laboratory, Upton, New York, USA; 2SA Instruments, Inc, Stony Brook, New York, USA; 3SUNY at Stony Brook, Stony Brook, New York, USA

A Data acquistion system with application software has been developed allowing the retrospective reodering of acquired MR data prior to reconstruction, and is used for the Cardiac Imaging of mice on a 9.4 T Bruker MRI system. Waveforms for respiratory, Electrocardiogram, Blood pressure and Peripheral pulse measurements were acquired simultaneously to the MRI acquisiton, thereby allowing the same MRI dataset to be reconstructed using reodering schemes based upon each of the different physiological waveforms. Quantitative evaluation of the cine images made using each of the monitoring waveforms is presented. Advanced strategies refining the reordering using data from multiple waveforms is also presented.

13:30 2885. MRI Tagging of in Vivo Ventricular Function Reflects Histological and Cellular Changes in α-Dystrobrevin Knockout Mice Wei Li1, 2, Wei Liu3, Allen Ye4, Priyanajana Chaudhuri4, Suhanti Banerjee4, Xin Yu, 24 1Case Western Reserve University, Cleveland , Ohio, USA; 2Cleveland, Ohio, USA; 3Philips Research North America, Bariarcliff Manor, New York, USA; 4Case Western Reserve University, Cleveland, Ohio, USA

Dystrophin-glycoprotein complex (DGC) maintains the structural integrity of myocardium. It also plays important signaling roles through nNOS. α-Dystrobrevin deficiency leads to nNOS displacement from DGC, leading to the development of cardiac lesions at an older age. In the current study, the impact of impaired DGC signaling and the development of cardiac lesions on in vivo ventricular function was examined with MRI tagging in α-dystrobrevin knockout mice. Potential mechanisms responsible for altered ventricular function were explored by histological and cellular studies.

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14:00 2886. Functional Cardiac Phenotyping of Vasoactive Intestinal Peptide (VIP) Deficient Mice by MR Microscopy S. David Smith1, Anthony Szema2, Sami I. Said2, Helene Benveniste1, 2 1Brookhaven National Laboratory, Upton, New York, USA; 2Stony Brook University, Stony Brook, New York, USA

Mice with deletion of the gene for VIP exhibit spontaneous pulmonary arterial hypertension (PAH) and vessel remodeling in the absence of hypoxemia with pathology showing thickened pulmonary vessels. We hypothesized that VIP deficient mice with known spontaneous PAH would also develop a decreased functional capacity of their right ventricle. We tested this hypothesis using MR microscopy. Quantitative analysis of cardiac MR microscopy images of VIP deficient mice revealed dilated right ventricles and reduced ejection fractions.

14:30 2887. Effect of Iron Oxides on Tag MRI at 1.5T in a Rat Myocardial Infarct Model Jean-Luc Daire1, Jean-Noel Hyacinthe1, Karin Montet-Abou1, Jean-Pascal Jacob1, Denis Morel1, Jean-Paul Vallée1, Xavier Montet1 1Geneva University Hospital, Geneva, Switzerland

This paper proves that despite high accumulation of iron oxides in myocardium infarct, Tag MRI at 1.5T can be realized and analysed in small rodent. The observed defect of contraction in circumferential strains corresponds to the hypointense region containing iron oxides.

15:00 2888. A Spiral K-Space Trajectory Enables Phase Contrast Measurements of Blood Flow in Curved Sections of the Mouse Aorta Robert L. Janiczek1, Brett R. Blackman1, R. Jack Roy1, Scott T. Acton1, Craig H. Meyer1, Frederick H. Epstein1 1University of Virginia, Charlottesville, Virginia , USA

Conventional rectilinear k-space trajectories can result in displacement artifacts due to movement of spins between excitation and data acquisition, and signal loss due to phase dispersion. Spiral trajectories have long been used for human MRI due to their desirable flow characteristics caused by their short echo-times and low gradient moments. However, these methods have yet to be applied to imaging small animals on high-field small-bore MRI systems. We present phase-contrast data at 7T in the mouse aorta and demonstrates these advantages allow PC data to be obtained in more regions of the mouse vasculature than a rectilinear trajectory.

13:30 2889. Effect of SEA0400 on Cardiac Mn2+ Efflux Rates, Using T1-Mapping Manganese-Enhanced MRI (MEMRI) in a Murine Model Ben Waghorn1, 2, Yuhui Yang2, Brianna Klein2, Akemichi Baba3, Toshio Matsuda3, Nathan Yanasak2, Tom Hu2 1Georgia Institute of Technology, Augusta, Georgia, USA; 2Medical College of Georgia, Augusta, Georgia, USA; 3Osaka University, Osaka, Japan

The Na+/Ca2+ exchanger (NCX) is an important transporter for the regulation of intracellular Ca2+ concentration. This study uses T1-mapping of murine cardiac Manganese-Enhanced MRI to quantitatively assess the rate of signal decay post Mn2+ infusion. A 50% attenuation of the signal in the left ventricular free wall, normally enhanced by Mn2+, is observed within approximately 2.5 hours post infusion. By inhibiting the NCX with SEA0400, we can proceed to characterize a trend of Mn2+ efflux modulation. Future work to study the actions of the NCX in detail will be undertaken using various pharmaceutical agents.

Non-Contrast Enhanced MRA Hall D Wednesday 13:30-15:30

13:30 2890. The Non-Contrast-Enhanced Hepatic MR Angiography with True Steady-State Free-Precession and Time Spatial Labeling Inversion Pulse: Optimization of the Technique and Preliminary Results Kotaro Shimada1, Hiroyoshi Isoda2, Tomohisa Okada2, Yoji Maetani2, Shigeki Arizono2, Yuusuke Hirokawa2, Toshikazu Kamae2, Kaori Togashi2 1Kyoto University Graduate School of Medicine , Kyoto, Japan; 2Kyoto University Graduate School of Medicine, Kyoto, Japan

Our purpose is to delineate the hepatic arteries selectively by using respiratory-triggered three-dimensional true steady-state free-precession with time spatial labeling inversion pulse (T-SLIP). T-SLIP is a kind of arterial spin labeling which can provide quantitative and selective inflow information by placing the inversion pulse at any place independent of the imaging area before data acquisition and suppress background signal. 21 healthy volunteers were examined. As a result, selective and high contrast visualization of the hepatic arteries was acquired in 20 cases without exogenous contrast agent. We report our initial experience and describe the optimization of this protocol.

14:00 2891. Renal Artery MRA at 3.0T: Initial Clinical Experience with Respiratory-Triggered Non-Contrast-Enhanced Phase Contrast with Vastly Under-Sampled Isotropic Projection Reconstruction (PC-VIPR) Darren Lum1, Christopher Francois1, Kevin Johnson1, Scott Reeder1, Oliver Wieben1, Thomas Grist1 1University of Wisconsin - Madison, Madison, Wisconsin, USA

In this study, we present our initial clinical experience with respiratory-triggered, non-contrast enhanced PC-VIPR MRA of the abdominal vessels at 3.0T. We demonstrate comparable image quality between PC-VIPR and 3D contrast enhanced MRA. Furthermore, PC-VIPR provides improved conspicuity of the segmental renal arteries due to the subtraction of stationary background tissues. Finally, we find good agreement between the two techniques for measurements of vessel diameter. In patients who cannot receive contrast secondary to the risk of nephrogenic systemic fibrosis, PC-VIPR may serve as an alternative to abdominal 3D contrast enhanced MRA. Further validation and optimization of this technique is ongoing.

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14:30 2892. ECG Triggered Acquisition Non-Contrast Enhanced (TRANCE) MRA at 3.0Tesla in Peripheral MRA Takeshi Ishimoto1, Takayuki Ikeda1, Naomi Yamamoto1, momoe Kawakami1, Masaru Ishihara2, Eiji Okamoto3, Tomoyuki Okuaki4 1Hyogo Brain and Heart Center, Himeji, Japan; 2Hyogo Prefectural Kakogawa Hospital, Kakogawa, Japan; 3Philips Electronics Japan, LTD., Osaka, Japan; 4Philips Electronics Japan, LTD., Minato-ku, Japan

Recently, non-contrast enhanced MRA techniques were clinically useful and widely use in routine examination, rapidly gaining in clinical importance. The purpose of this study was to evaluation the technical feasibility and clinical utility of ECG triggered acquisition Non-Contrast Enhanced (TRANCE) MRA at 3.0Tesla in patients with peripheral vascular disease. In peripheral MRA, TRANCE MRA at 3.0Tesla provided diagnostic images comparable with those of CTA and DSA without the administration of contrast agent. This technique will be noninvasive standard examination in the diagnosis of peripheral vascular disease as well as 1.5Tesla.

15:00 2893. Visualization of the Lenticulostriate Artery with Flow-Sensitive Black-Blood Imaging in Comparison with Time-Of-Flight MR Angiography K. Gotoh1, T. Okada1, Y. Miki1, M. Ikedo2, A. Ninomiya2, T. Kamae1, K. Togashi1 1Kyoto University Graduate School of Medicine, Kyoto, Japan; 2Toshiba Medical Systems, Ohtawara, Japan

We visualized lenticulostriate arteries (LSAs) by using Flow-sensitive Black Blood (FSBB) method, which is a variant of 3D-FE (field echo) and make it possible to attenuate the signal of arteries by applying very weak motion probing gradients to disturb refocusing of moving spins only. We compared FSBB with TOF on visualzed LSAs of 19 volunteers and had good results.

13:30 2894. Non-Contrast-Enhanced MR Portography Using 3D Inversion Recovery-In Flow Iterative Spatial Saturation Pulses (IR-IFIS) Steady-State Free Precession (FIESTA) Motoyuki Katayama1, Takayuki Masui1, Kimihiko Sato1, Hidekazu Seo1, Megumi Ishii1, Masayoshi Sugimura1, Kazuhiko Ito1, Mitsuharu Miyoshi2, Naoyuki Takei2, Tetsuji Tsukamoto2 1Seirei Hamamatsu General Hospital, Hamamatsu, Japan; 2GE Yokogawa Medical Systems. Ltd, Hino, Japan

We optimized the parameters of IFIS FIESTA technique in normal volunteer, and applied this technique to the MR examinations in patients with hepatobiliary disorder. The non-contrast-enhanced 3D IR-IFIS FIESTA technique provides good image quality MR portography. When gadolinium is not usable, this sequence might be an alternative choice of method.

14:00 2895. T1 Insensitive Background Saturation by Two Inversion Pulses for Flow-Prep Non-Contrast-Agent MR Angiography Mitsuharu Miyoshi1, Naoyuki Takei1, Tetsuji Tsukamoto1 1GE Yokogawa Medical Systems, Hino, Japan

Flow-Preparation-pulse (Flow-Prep) is a preparation pulse that enhances flow signal and suppresses stationary signal. This is used for Non-Contrast-Agent MRA in this study. However, the stationary background signals remain because of T1 relaxation between the Flow-Prep preparation and the data acquisition. Although T2-Prep and Spectral IR can suppress the kidney and the fat signals, short-T1 intestinal contents remain high signal background. We developed Flow-Prep with two IR pulses, which enabled T1 insensitive background suppression. Aorta and renal artery signals were depicted in high contrast. Intestinal contents, kidney and fat signals were suppressed homogeneously.

14:30 2896. Using Phase Contrast MRA for the Diagnosis of Pelvic Congestion Syndrome Luis Andres Meneses1, 2, Cristian Tejos1, 3, Mario Fava1, Marcelo Andia1, 3, Moshe Pincu4, Jorge Cifuentes4, Pablo Irarrazaval1, 3 1Pontificia Universidad Catolica de Chile, Santiago, Chile; 2Biomedical Imaging Center, Santiago, Chile; 3Biomedical Imaging Center, Santiago, Chile; 4Hospital Sotero del Rio, Santiago, Chile

In Pelvic congestion syndrome (PCS) ovarian veins (OV) is characterized by abnormal blood flow. We evaluated the accuracy of flow velocity (measured with PC-MRA) as a diagnostic criterion. We studied 16 OV with PC-MRA and with direct venography (DV) as a reference test. PC-MRA showed the same results as DV for the 12 pathological veins. PC-MRA correctly identified 2 of the 4 normal veins. We believe that in the 2 cases with discrepancy, PC-MRA could to detect an early stage of the PCS which DV could not to identify. PC-MRA provides useful diagnostic tools for the diagnosis of PCS.

15:00 2897. Non-Contrast MRA Using ECG-Triggered 3D Valuable Flip Angle Fast Spin Echo for the Vessels of the Pelvis and Legs with Total Imaging Matrix Coil Satoru Kitano1, Shinji Hirohashi2, Nagaaki Marugami1, Junko Takahama1, wataru higashiura1, Toshiaki Taoka1, Kimihiko Kichikawa1 1Nara Mediacl University, Kashihara, Japan; 2Osaka gyoumeikan Hospital, Osaka, Japan

The purpose of this study is to clearly 3D valuable flip angle TSE with Tim (Total imaging matrix) array coil system can be applied to 3D non contrast body MRA. 5 patients underwent 3D non contrast body MRA in a three step table feed technique. Pelvic, femoral and lower leg MRA were obtained ECG-triggered 3D valuable flip angle TSE (space). 3D non-contrast MRA with Tim coil system is a promising technique in the diagnosis of the arterial vascular system of the vessels of the pelvis and legs.

13:30 2898. Non-Contrast MRA with FIESTA Using IR-IFIS for Selective Visualization the Renal Arteries Takayuki Masui1, Motoyuki Katayama1, Kimihiko Sato1, Hidekazu Seo1, Kazuhiko Ito1, Hiroki Ikuma1, Masayoshi Sugimura1, Naoyuki Takei2, Mitsuaharu Miyoshi2, Tetsuji Tsukamoto2, Megumi Ishii1, Akihiko Kutsuna1 1Seirei Hamamatsu General Hospital, Hamamatsu, Japan; 2GEYMS, Hino, Japan

Non-contrast MRA for the aorta and renal arteries was obtained using respiratory-triggered peripheral-gated 3D FIESTA with Inversion recovery-In Flow Iterative Spatial Saturation pulse (IR-IFIS), based on tagging of the blood in the heart and thoracic aorta, which is running through the abdominal aorta, with background suppression by non-selective inversion pulse. The optimal parameters for normal volunteers were evaluated and the abdominal aorta and renal arteries were successfully visualized. In the patients with suspected renal tumors, contrast MRA provide still better information of the aorta and renal arteries, non contrast MRA has potentials to visualize the selected arteries of interest.

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14:00 2899. Non-Enhanced MR Angiography of the Uterine Vessels; Optimization of the Sequence Parameters Takashi Koyama1, Tomohisa Okada2, Koji Fujimoto2, Toshikazu Kamae2, Ayako Niyomiya3, Saori Satou3, Nobuyasu Ichinose3, Kaori Togashi2 1Kyoto University Hospital, Kyoto, Japan; 2Kyoto University, graduate school of medicine, Kyoto, Japan; 3Toshiba Medical Systems, Tokyo, Japan

The purpose of this study is to evaluate the difference of depiction and contrast of the uterine vessels in different inversion time in non-enhanced MRA utilizing Time-SLIP. Nonenhanced Time-SLIP MRA was performed in eight healthy volunteers combining separately with SSFP and FASE at different TI times. With FASE, images the difference of contrast between arteries and veins dose not significantly differ, although images with longer TI tend to show better depiction of the uterine veins. With SSFP, TI of 1800ms provides best depiction of the both arteries and veins, and best contrast between them.

14:30 2900. Non-Contrast Time-Resolved 2D Fresh Blood Imaging (FBI) Mitsue Miyazaki1, 2, Toshiro Fukuta2, Girish Srinivasan1, Robert Anderson3, nobuyasu Ichinose2, Shinichi Kitane4 1Toshiba Medical Research Institute, Vernon Hills, USA; 2Toshiba Medical Systems Corp., Otawara, Japan; 3Toshiba Medical Research Institute, Ohio, USA; 4Toshiba Medical Engineering Co., Japan

With the recent association of gadolinium contrast agent and nephrogenic systemic fibrosis (NSF) disease, there is growing interest in using non-contrast MRA techniques as alternatives for contrast enhanced (CE) MRA. As a result, there have been many non-contrast MRA techniques reported. However, many of studies were limited to the morphology of the vessel lumen. In this study, a new non-contrast time-resolved MRA technique, using a keyhole technique and parallel imaging, is proposed to shorten scan time. Furthermore, assessment of the proposed technique was investigated to obtain the peripheral arterial hemodynamic information.

15:00 2901. Non-Contrast MRA of the Toes Using Time-Spatial Labeling Inversion Pulse (Time-SLIP) and Optimization of Flow-Spoiled Gradient Pulses for the Assessment of Foot Arteries in Flow-Spoiled Fresh Blood Imaging (FBI) Jun Isogai1, Mitsue Miyazaki2, Takeshi Shimada1, Hideo Hatakeyama1, Takashi Yamada1, Naoto Matsuo1, Shizuaki Maejima1, Kenji Yodo3, Tomoko Miyata3 1Hasuda Hospital, Hasuda, Japan; 2Toshiba Medical Research Institute USA, Illinois, USA; 3Toshiba Medical Systems Corporation, Japan

Visualization of small arteries of the foot and toes is quite difficult in using conventional non-contrast MR angiography (MRA) techniques, including time-of-flight (TOF) and phase contrast MRA, due to tortuous vessels out of plane and slow velocity. In addition, Gadolinium-enhanced MRA has also several problems on an injection rate or the amount of contrast materials. Due to the recent concerns of Gadolinium-related Nephrogenic Systemic Fibrosis (NSF), non-contrast MRA solutions have gained interest. Non-contrast flow-spoiled fresh blood imaging (FBI) and time-spatial labeling inversion pulse (time-SLIP) were investigated for visualization of small arteries of the foot and toes.

13:30 2902. FBI-Navi for Easy Determination of Diastolic and Systolic Triggering Phases in Non-Contrast Fresh Blood Imaging (FBI) Naoyuki Furudate1, Mitsue Miyazaki, 12 1Toshiba Medical Systems, Otawara, Japan; 2Toshiba Medical Research Institute USA, Vernon Hills, USA

Due to the recent association of gadolinium contrast agent dose and nephrogenic systemic fibrosis (NSF) disease, there have been increasing interests in MRA examination using non-contrast MRA techniques as alternatives. Cardiac gated FSE-based flow-spoiled fresh blood imaging (FS-FBI), allows separation of arteries from veins in peripheral MRA. To find the suitable systolic and diastolic delays, single-slice multiple phases (ECG-prep) images are acquired. However, the determination of systolic and diastolic triggering delays can be problematic. In this study, we propose a new software algorithm, (FBI-Navi), to determine the diastolic and systolic trigger delays to reduce the operational burden.

14:00 2903. Optimization of Non-Contrast Renal MRA Using a TI-Prep Scan for Time-Spatial Labeling Pulse (Time-SLIP) in 3D Balanced SSFP Junji Takahashi1, Yoshinori Tsuji1, Yusuke Hamada1, Takashi Yoshida1, Sachiko Isono2, Ayako Ninomiya2, Yoshimori Kassai3, Mitsue Miyazaki, 34 1Toranomon Hospital, Tokyo, Japan; 2Toshiba Medical Systems, Tokyo, Japan; 3Toshiba Medical Systems Corp., Otawara, Japan; 4Toshiba Medical Research Institute USA, Vernon Hills, USA

Non-contrast-enhanced renal 3D MRA using time-spatial labeling inversion pulse (time-SLIP) is presented to depict the renal arteries. The contrast between the renal arteries and background signals was best visualized with a black blood inversion time (BBTI) of around 1100 msec. However, the depiction of the smaller renal branches depends on the flow speed in patients. We have applied a 2D BBTI preparation scan, which provides a series of single shot images with different BBTI times, prior to the 3D scan. Good correlation was obtained between the 2D BBTI preparation scan and 3D scan in both volunteers and patients.

14:30 2904. The Value of CINE Bright Blood Sequences in the Evaluation of Cryptogenic Stroke Larry Allen Kramer1, Eduardo J. Matta2, Anuradha T. Rao2, Durga K. Pai2, Khader M. Hasan2 1University of Texas-Houston, Houston, USA; 2UT-Houston, Houston, USA

Magnetic Resonance Venography (MRV) of the pelvic venous system is utilized to evaluate for occult pelvic venous thrombosis in patients with crytogenic stroke. Echocardiographic evidence of a right to left shunt and negative clinical exam or lower extremity venous doppler study results in investigation of the pelvic venous system with MRV. Because of tortuosity of the pelvic venous system and valves flow artifacts are common. To improve specificity CINE bright blood sequences were utilized to evaluate flow defects seen on the conventional 2D time-of-Flight gradient-echo sequences. Our results show that CINE sequences readily distinguishes clot from flow artifact.

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15:00 2905. Accelerated 3D Phase-Contrast MR Angiography Using Time-Interleaved Autocalibration (TCAL) Anja C.S. Brau1, Wei Sun2, Philip J. Beatty1 1GE Healthcare, Menlo Park, California , USA; 2GE Healthcare, Waukesha, Wisconsin, USA

This work demonstrates the feasibility of time-interleaved autocalibration (TCAL) for improving the imaging efficiency of accelerated 3D PC MRA. By sharing the calibration burden across velocity-encoding measurements, TCAL reduces the calibration time penalty by 4x while retaining robustness to motion and compatibility with PC reconstruction.

13:30 2906. Non-Contrast Enhanced Renal Artery Angiography with a Respiratory Gated 3D Radial Linear Combination SSFP Sequence Jessica L. Klaers1, Kevin M. Johnson1, Christopher Francois1, Ethan K. Brodsky1, Youngkyoo Jung1, Oliver Wieben1, Walter F. Block1 1University of Wisconsin - Madison, Madison, USA

An ultrashort TR dual-echo 3D radial Linear Combination SSFP (LCSSFP) sequence is used in conjunction with a novel real-time adaptive expiratory respiratory gating method for high resolution renal non-contrast enhanced MRA. This is especially applicable for use in patients with renal insufficiency in the wake of the recent discovery of the link between Nephrogenic Systemic Fibrosis (NSF) and Gd based contrast agents. The promising initial results give excellent depiction of the renal arteries, including branch vessels, not typically seen in contrast enhanced exams.

14:00 2907. Phase Contrast Stack of Stars Imaging Steven Kecskemeti1, 2, Kevin M. Johnson1, Oliver Wieben1, Charles Mistretta1, 2 1University of Wisconsin , Madison, Wisconsin, USA; 2University of Wisconsin - Madison, Madison, Wisconsin, USA

A hybrid radial-Cartesian “stack of stars”(SOS) phase contrast (PC)method has been developed to overcome some of the limitations of conventional Cartesian based PC acquisitions, such as long scan times and artifacts from cardiac pulsatility and intravoxel dephasing. The PC SOS method can be undersampled without aliasing artifact or a loss of resolution as in the Cartesian method, thereby reducing scan times. In addition, the distributed nature and low frequency over sampling of this sequence reduces cardiac pulsatility artifacts. We present results comparing the PC SOS images to those obtained with a clinical Cartesian PC sequence.

14:30 2908. Non Contrast MRA of Renal Transplant Vasculature Using 3D TrueFISP Natasha Berg1, John Joseph Sheehan1, Xiaoming Bi2, Peter J. Weale2, Randall Ramsay1, Renate Jerecic2, James C. Carr1 1Northwestern University, Chicago, Illinois, USA; 2Siemens Medical Solutions, Chicago, Illinois, USA

Contrast enhanced Magnetic Resonance Angiography (CEMRA) has previously been considered a safe alternative to CTA or conventional angiography in the assessment of the renal transplant patient. However, non contrast techniques may be more desirable in this population due to renal impairment. We examined a novel non contrast MRA (NCMRA) technique using a 3D True FISP sequence with selective inversion pulse to assess the renal vasculature in post-transplant patients. The NCMRA technique demonstrated equivalent and superior imaging of post-transplant vasculature compared to CEMRA. This technique may be clinically advantageous for renal transplant patients who are unsuitable candidates for contrast administration.

15:00 2909. Clinical Evaluation of IR Prepared 3D TrueFISP for Non-Contrast Abdominal Angiography - A Comparison to Ce-MRA Peter J. Weale1, Natasha Berg2, John Sheehan2, Randall Ramsay2, James Carr2, Renate Jerecic1, Xiaoming Bi1 1Siemens Medical Solutions, Chicago, Illinois, USA; 2Northwestern University, Chicago, Illinois, USA

A qualitative and quantitative comparison in patients referred for MRA of a non-contrast approach to abdominal angiography using a 3D IR prepared TrueFISP sequence with a selective IR preparation with spatial localization independent from the imaging volume.

Myocardial Function: Human Studies Hall D Wednesday 13:30-15:30

13:30 2910. Strain Encoding MRI (SENC) for the Quantification of Regional Ventricular Function in Pulmonary Arterial Hypertension Monda L. Shehata1, 2, Lynette Brown1, Dirk Lossnitzer3, Jens Vogel-Claussen1, Joao A. C. Lima1, Reda E. Girgis1, Paul M. Hassoun1, David A. Bluemke1, Nael F. Osman1 1Johns Hopkins University, Baltimore, USA; 2Ain Shams University, Cairo, Egypt; 3Universty of Heidelberg, Heidelberg, Germany

Right ventricular function evaluation and monitoring are considered important prognostic factors in many cardiac and/or pulmonary disorders especially pulmonary arterial hypertension (PAH)which eventually leads to RV dysfunction and failure. CMR is a versatile tool for global and regional ventricular function evaluation. Tagging has been used for LV function quantification . However, in RV, this technique is limited by thin wall. Strain encoding (SENC)MR is a technique that applies tags parellel to the imaging plane with narrow tag spacing yielding high spatial resolution images. Using 3T MRI, 5 PAH patients were imaged using SENC to quatify regional longitudinal strain (ELL) in RV and interventricular septum and we compared them to 6 healthy controls. Reduced ELL was noted at anterior RV free wall and septum (p<0.05). SENC MR can provide a rapid tool for RV function quantification and monitoring in PAH patients.

14:00 2911. Imaging Cardiac Motion and Flow Simultaneously During Exercise Stress Studies Using SPAMM N' EGGS Smita Sampath1, John Andrew Derbyshire1, Maria J. Ledesma-Carbayo, Elliot R. McVeigh1 1National Institutes of Health, Bethesda, Maryland, USA

Detecting myocardial mechanical dysfunctions and trans-valvular flow abnormalities during the stress of exercise provides early diagnostic indicators in patients with valvular diseases. Since these events are transient in nature, the ability to acquire these measurements simultaneously is important. In this study, we apply a new MR imaging technique called SPAMM n’ EGGS (spatial modulation of magnetization acquisitions with encoded gradients for gauging speed), that combines tagging and phase-contrast imaging principles to provide simultaneous measurements of longitudinal left ventricular compression and trans-mitral chamber blood velocity during exercise stress studies in normal volunteers.

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14:30 2912. Evaluation of CSPAMM with Steady State Free Precession for Myocardial Tagging at 3T Jean-Noel Hyacinthe1, Jean-Luc Daire, Joost P.A. Kuijer2, Magalie Viallon1, Pierre-Frederic Keller1, Pierre Croisille3, Jean-Paul Vallée1 1Geneva University Hospital, Geneva, Switzerland; 2VU University Medical Center, Amsterdam, Netherlands; 3Université Claude Bernard lyon 1, Lyon, France

Imaging at 3T, using CSPAMM and/or SSFP are efficient means to improve myocardial tagging. In this study we evaluate the combination of all of them in 6 volunteers and 10 patients. CSPAMM with balanced SSFP at 3T combines gain of absolute CNR from the field strength with improved relative tag contrast, easing thus the post processing, and sensitivity to typical SSFP banding artefacts is drastically reduced. Moreover, the technique shows no loss of accuracy in strain measurements, and an accurate diagnosis was performed in patients.

15:00 2913. Real-Time Cine Imaging at Peak Exercise Stress with a 32-Channel Cardiac Array, TGRAPPA, and Karhunen-Loeve Image Filtering Mihaela Jekic1, 2, Yu Ding2, Eric Foster1, 3, Subha V. Raman1, 2, Orlando P. Simonetti1, 2 1The Ohio State University, Columbus, USA; 2Dorothy M. Davis Heart and Lung Research Institute, Columbus, USA; 3Dorothy M. Davis Heart and Lung Research Institiute, Columbus, USA

Rapid heart rates and heavy breathing associated with exercise stress testing demand higher temporal resolution than is attainable by current methods. Our standard exercise stress protocol utilizes a 12-channel coil and parallel acceleration rate 4, resulting in temporal resolution of approximately 52 msec, but further gain in temporal resolution is desired. We investigated the performance of real-time cardiac imaging immediately after maximal treadmill exercise by the combined application of a 32-channel cardiac array coil, TGRAPPA rate 5 acceleration, and KLT filtering, and quantitatively compared SNR to our standard method. We successfully increased temporal resolution to 43.7 msec without compromising spatial resolution or SNR.

13:30 2914. Image Based Real-Time Monitoring of Cardiac Parameters for Stress Testing or Interventions Corinna S. Maier1, 2, Peter Kellman3, Michael Bock2, Wolfhard Semmler2, Christine H. Lorenz4 1Siemens Corporate Research, Princeton, New Jersey, USA; 2German Cancer Research Center (dkfz), Heidelberg, Germany; 3National Institutes of Health, Bethesda, Maryland, USA; 4Siemens Corporate Research, Baltimore, Maryland, USA

The proposed framework provides a method for real-time monitoring and detecting changes for regional and global ejection fraction (EF) and heart rate (HR) during a cardiovascular intervention or dobutamine stress test under MRI. Basal, mid and apical MRI left ventricular (LV) short axis images are acquired. End systolic and end diastolic volumes are estimated in each heart cycle based on the results of an Expectation-Maximization segmentation algorithm. EF and HR are calculated continuously, are corrected and smoothed and a change detection algorithm is applied. Estimated EF and HR are compared to the offline calculated EF and the recorded ECG, respectively.

14:00 2915. Left Ventricular Internal Flow in Patients with Dyssynchronous Heart Failure: Quantification by Cine MRI Brandon K. Fornwalt1, 2, Patrick C. Gonzales1, Jana G. Delfino1, 2, Robert L. Eisner1, 3, Angel R. León1, 3, John N. Oshinski1, 2 1Emory University, Atlanta, Georgia, USA; 2Emory/Georgia Institute of Technology, Atlanta, Georgia, USA; 3The Carlyle Fraser Heart Center, Atlanta, Georgia, USA

Better methods to quantify left ventricular dyssynchrony are needed to identify candidates for cardiac resynchronization therapy (CRT). Dyssynchrony creates abnormal displacement of blood within the left ventricle, and this “internal flow” may represent the most direct measure of dyssynchrony. We hypothesized that internal flow could be quantified from cine-MRI and would be increased in patients undergoing CRT compared to controls. Systolic internal flow was 21±10% in 10 patients and 2±2% in 10 controls (p<0.001). A threshold systolic internal flow of 6% discriminated patients from controls with 100% accuracy. MRI-based quantification of ventricular internal flow may be useful in diagnosing dyssynchrony.

14:30 2916. Saturation-Band Cine MRI Improves Detection of Intracardiac Shunt Wiphada Patricia Bandettini1, Andrew Ernest Arai1 1National Institutes of Health, Bethesda, Maryland, USA

Saturation-bands interleaved with gradient echo cine MRI provides “tagged” blood, but its use in the assessment of congenital intracardiac shunt has been limited. The technique is easily implemented and can be added to a standard congenital imaging protocol. The purpose of this study was to demonstrate the utility of adding a saturation pulse to gradient recalled echo cine MRI to assist in the identification and anatomic delineation of intracardiac shunts.

15:00 2917. Assessment of Left Ventricular Volume and Mass at 3.0T Using SSFP and FLASH Cine Imaging Neil Woodhouse1, Dan Hagger1, Jim M. Wild1 1University of Sheffield, Sheffield, UK

SSFP is the accepted standard for cine imaging of cardiac function at 1.5 T. Recent work at 3T suggests SSFP offers increased contrast to noise ratio (CNR) over spoiled gradient echo methods (FLASH). Left ventricular (LV) measurements were evaluated at 3.0T using SSFP and FLASH sequences in 6 healthy volunteers. Significant differences in both mass and volume were demonstrated between both imaging methods. FLASH systematically overestimated mass and underestimated volume (p<0.05) when compared to SSFP although it was significantly lees affected by magnetic susceptibility artefact. FLASH appears to be the more robust sequence at 3.0T despite having a lower CNR.

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MRA Contrast Agents Hall D Wednesday 13:30-15:30

13:30 2918. High Resolution Arterial MRA of the Lower Limb by Hybrid K-Space Reconstruction Before and After Administration of Vasovist Bloodpool Constrast Agent Egbert Gedat1, Rainer Kirsch2, Mojgan Mohajer1, Bernhard Meyer1, Bernd Frericks1 1Charité Universitätsmedizin Berlin, Berlin, Germany; 2Siemens Medical Solutions, Erlangen, Germany

High resolution CE MRAs of the lower limb were acquired in the steady state phase after administration of bloodpool contrast agent gadofosveset trisodium. To remove the veins and facilitate the assessment of the arteries they were computationally combined with first pass image volumes by replacing central k-space. 18 patients were examined yielding resulting MIPs of the lower limbs’ arteries of good quality for 8 patients. The veins were mostly removed and the high resolution was preserved. For the other patients either the distribution of the contrast agent was inappropriate or patient motion had occurred.

14:00 2919. MR Phlebography with a Blood Pool Contrast Agent in Patients with Peripheral Arterial Occlusive Disease Guido Matthias Kukuk1, Dariusch Reza Hadizadeh1, Markus Moehlenbruch1, Kai Wilhelm1, Arne Koscielny1, Frauke Verrel1, Hans Heinz Schild1, Winfried Albert Willinek1 1University of Bonn, Bonn, Germany

Contrast-enhanced MR angiography is routinely used for evaluation of peripheral arterial occlusive disease (PAOD). The introduction of the intravascular contrast agent Gadofosveset Trisodium allows for longer acquisition times with high T1 relaxivity resulting in higher spatial resolution imaging of both arteries and veins during the steady state phase. 139 patients were referred to MRA for evaluation of PAOD at 1.5T. In 46/139 patients (33%) we incidentally found clinically relevant venous diseases including deep vein thrombosis, varicosis or arteriovenous fistula. In conclusion, the combination of MRA and MR phlebography appears to be a promising clinical application for blood pool contrast agents.

14:30 2920. Gadofosveset-Enhanced Steady State MRA of the Peripheral Vessels with Dixon Fat-Saturation Henrik Jakob Michaely1, Ulrike I. Attenberger2, Harald Kramer2, Maximilian F. Reiser2, Stefan O. Schoenberg1 1University Hosptial Mannheim, Mannheim, Germany; 2University of Munich, Munich, Germany

In this study the feasibility and image quality of a two-point Dixon MRA during the steady state after the injection of gadofosveset was compared to a MRA with conventional spectral fat-saturation. Using the Dixon technique a significantly higher SNR and CNR were achieved due to a more homogenous fat-suppression than with spectral fat-suppression.

15:00 2921. Comparison of Renal MRA and Angiography Data in the CORAL Study Honglei Zhang1, Alan Matsumoto2, Timothy Murphy, Don Cutlip3, Katie Wade3, Christopher J. Cooper4, Lance Dworkin5, Martin R. Prince1 1Weill Medical College of Cornell University, New York, New York, USA; 2Virginia University, USA; 3Harvard Clinical Research Institute, USA; 4University of Toledo College of Medicine, Toledo, Ohio, USA; 5Rhode Island Hospital, USA

Fifty-five renal MRAs were reviewed by MRA core lab for randomization in to CORAL study, of which 26 (47%) were diagnosed as having > 60% stenosis. For the 7 randomized to balloon angioplasty and stent therapy, angiography confirmed that MRA correctly identified 8 lesions as hemodynamically significant with an accuracy of 100%. In 35 MRAs with local reports, MRA readings by coral lab were consistent with the readings by local radiologist in 19 patients (54%). These included 15 positive studies and 4 negative studies. In the remaining 16 patients, local radiologists overestimated the severity of renal artery stenoses.

Coronary MRA Hall D Thursday 13:30-15:30

13:30 2922. Whole Heart Coronary MR Angiography Acquired with 32-Channel Cardiac Coils for the Detection of Coronary Artery Disease Motonori Nagata1, Hajime Sakuma1, Nanaka Ishida1, Tairo Kurita1, Yoko Mikami1, Hiroshi Nakajima1, Katsuya Onishi1, Masaaki Ito1, Kan Takeda1 1Mie university hospital, Tsu, Japan

Use of 32 channel coils allows for acquisition of whole heart coronary MRA in a reduced imaging time and with high study success rate, which resulted in considerably improved overall detection rate of CAD in subjects who underwent coronary MRA.

14:00 2923. Signal-To-Noise Ratio Enhancement in Coronary MRA Using Parallel Imaging Jing Yu1, Michael Schär1, Evert-jan P.A. Vonken1, Sebastian Kelle1, Matthias Stuber1 1Johns Hopkins University, Baltimore, Maryland, USA

Coronary MRA with short acquisition windows is limited by SNR. We propose a method to enhance SNR based on parallel imaging in conjunction with a reduced number of radiofrequency excitations while the scanning time remains unchanged. A practical method to quantify SNR on images obtained with parallel imaging was developed as well. Numerical simulations predict that the SNR gain using the proposed method is greatest for very short acquisition windows. These theoretical findings are in good agreement with in vitro and in vivo results obtained in this study.

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14:30 2924. Contrast-Enhanced MR Angiography: A Helpful Methodology to Detect Coronary Atherosclerotic Plaque Xihai Zhao1, 2, Xin Liu3, Liuquan Cheng2, Li Yang2, Zulong Cai2, Chun Yuan1 1Vascular imaging lab. , Seattle, Washington, USA; 2deparment of radiology, Beijing, People's Republic of China; 3Departments of Radiology, Chicago, Illinois, USA

This study focus on using contrast-enhanced MR angiography to improve the SNR and CNR of MR images and to increase the detection rate of coronary atherosclerotic plaque.

15:00 2925. Contrast-Kinetics-Resolved Whole-Heart Coronary MRA Using 3DPR Peng Lai1, Feng Huang2, Sonia Nielles-Vallespin3, Xiaoming Bi4, Andrew C. Larson1, Renate Jerecic4, Debiao Li1 1Northwestern University, Chicago, Illinois, USA; 2Invivo Corporation, Gainesville, Florida, USA; 3Siemens AG Medical Solutions, Erlangen, Germany; 4Siemens Medical Solutions, Chicago, Illinois, USA

In contrast-enhanced coronary MRA, a bolus scan is usually necessary to estimate the transit time from contrast injection to peak arterial enhancement. However, optimal timing of data acquisition often remains elusive due to variations of heart rates and respiratory gating efficiency as well as simultaneous myocardial enhancement. In this work a contrast-kinetics-resolved technique using 3DPR was developed which eliminates the tedious planning task and enables retrospective selection of the optimal coronary artery visualization for different coronary artery segments. Also, the center-k-space magnitude change could be used to approximate contrast kinetics during a scan, enabling automatic selection of optimal time frames.

13:30 2926. Contrast-Enhanced Coronary MR Angiography with Gd-DTPA Slow Infusion Liuquan Cheng1, Tao Li1, Haiyue Ju1, Xihai Zhao1, 2, Yuangui Gao1, Yi Wang3 1Chinese PLA General Hospital, Beijing, People's Republic of China; 2Northwestern University Medical School, Chicago, USA; 3Weill Medical College of Cornell University, New York, USA

The navigator-gated FIESTA coronary MRA was acquired during the slow infusion of Gd-DTPA. The SNR and image quality could be improved and it is more accurate than the non-contrast study in stenosis detection.

14:00 2927. Breath-Hold Whole-Heart Coronary MR Angiography (CMRA) by 2D-Parallel Acquisition Compared with Respiration-Gated CMRA Using a Multi-Element Body Coil Tomohisa Okada1, Shotaro Kanao1, Shigehide Kuhara2, Ikuo Aoki2, Ayako Ninomiya2, Saori Satou2, Toshikazu Kamae1, kimio Gotoh1, Kaori Togashi1 1Kyoto University Graduate School of Medicine, Kyoto, Japan; 2Toshiba Medical Systems Corporation, Ohtawara, Japan

The multi-element phased-array body coil is now widely available in clinical practice. It has capability of 2D-parallel imaging, which may largely reduce scan time. This study investigated the attainable quality of coronary MRA in breath-hold (BH) compared with respiration-gated (RG) CMRA. Examination of 14 healthy subjects resulted in scan time reduction approximately from 12 minutes to 34 seconds. The average quality score of visualization (0-4) was reduced by 0.93, however, proximal segments (#1-2, #5-7, #11) showed average scores over 2, which was considered usable for clinical evaluation.

14:30 2928. Whole Heart Coronary Vein Imaging Christian Stoeck1, 2, Dana C. Peters2, Yuchi Han2, Beth Goddu2, Warren J. Manning2, Sebastian Kozerke3, Reza Nezafat2 1ETH Zurich, Zurich, Switzerland; 2Beth Israel Deaconess Medical Center Harvard Medical School, Boston, Massachusetts, USA; 3Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland

Transvenous BiV lead implantation in cardiac resynchronization (CRT) therapy is preferred to surgical placement. However, for the transvenous approach, knowledge of the coronary vein anatomy is needed prior or during the implantation procedure. Recent studies showed the strength of cardiovascular MR in assessing coronary vein anatomy. In this study we investigated the use of MT-SSFP whole heart imaging to assess coronary vein anatomy.

15:00 2929. 2D Spin-Labeling Coronary MR-Angiography with Cartesian and Radial K-Space Sampling Marcus Katoh1, 2, Matthias Stuber3, Arno Buecker1, Rolf W. Gunther2, Elmar Spuentrup2, 4 1University Hospital Saarland, Homburg, Germany; 2RWTH Aachen University Hospital, Aachen, Germany; 3Johns Hopkins University Medical School, Baltimore, Maryland, USA; 4University Hospital Köln, Köln, Germany

3D spin-labeling coronary MR-angiography (cMRA) allows selective visualization of the coronary arteries. This technique is limited by a long scanning time as two 3D data sets must be subtracted. In this study, the value of a 2D approach was investigated. The coronary arteries of 8 volunteers were imaged on a 1.5 T MR-system using a navigator-gated and cardiac-triggered 2D SSFP cMRA sequence with Cartesian and radial k-space sampling. 2D spin-labeling cMRA allowed for selective visualization of the left and right coronary system within a minute. Radial k-space sampling proved to be superior with respect to artifact suppression, SNR, CNR and vessel border definition.

Contrast-Enhanced Myocardial Perfusion Imaging Hall D Thursday 13:30-15:30

13:30 2930. Free Breathing Myocardial Perfusion Using Navigator Slice Tracking and TSENSE Bryan Kressler1, Pascal Spincemaille2, Thanh D. Nguyen2, Jonathan W. Weinsaft2, Martin R. Prince2, Yi Wang1 1Cornell University, Ithaca, USA; 2Weill-Cornell Medical College, New York, USA

Conventional contrast enhanced myocardial perfusion imaging relies on a prolonged breath hold to eliminate respiratory motion. However, the contrast enhancement time course may be too long for patients to successfully suspend respiration, resulting in breathing motion and rendering image analysis difficult. In this work, navigator slice tracking is applied to myocardial perfusion, eliminating the need to perform breath holding and enabling acquisition of the entire contrast enhancement time course with minimal breathing motion. TSENSE acquisition and processing are applied to increase the number of slices that can be acquired. The technique is demonstrated in healthy volunteers and patients.

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14:00 2931. Dual Bolus Myocardial Stress Perfusion Quantification in Normals Yi Wang1, 2, Raphael Hazel1, Bin Luo1, Marguerite Roth1, Jing Han1, Nathaniel Reichek1, 2 1St. Francis Hospital, Roslyn, New York, USA; 2SUNY, Stony Brook, New York, USA

We studied Fermi model-based quantitative perfusion quantification methods in dual bolus myocardial adenosine stress perfusion and evaluated their absolute perfusion values at different dose in 16 normal volunteers. The results showed significant difference in average perfusion values both under stress (5.64 ml/min/g) and at rest (2.30 ml/min/g) at 0.05mM/kg standard contrast dose versus stress perfusion (2.07 ml/min/g) and rest perfusion (0.69 ml/min/g) when 0.005mM/kg contrast dose blood signal was used as the arterial input function. However, their flow reserves both dual bolus or standard dose only were significantly associated and their means were close (2.49 at SD versus 2.31 at DB). The flow reserve values showed good correlation with subject age and are consistent with PET findings in normals.

14:30 2932. First-Pass Myocardial Perfusion: Comparison Between Full-Dose Hybrid-EPI and Half-Dose Balanced-SSFP Peter D. Gatehouse1, Chiara Bucciarelli-Ducci, Jonathan C. Lyne, David N. Firmin, Dudley J. Pennell 1Royal Brompton Hospital, London, UK

Comparisons of these sequences at the same dose have shown abundant myocardial SNR for myocardial perfusion balanced SSFP compared to hybrid-EPI, but with more dark-rim subendocardial artefact in bSSFP. This study compared the two sequences for stress perfusion in 8 subjects, using reduced contrast agent dose for bSSFP to reduce one potential source of artefact (B0 distortion). While myocardial SNR with bSSFP remained equivalent or superior to hEPI, dark-rim artefact also occurred in normal segments more frequently in half-dose bSSFP than full-dose hEPI.

15:00 2933. Myocardial Magnetic Resonance Stress Perfusion Imaging at 3T Using a 1-Molar Contrast Agent Bernhard Daniel Klumpp1, Christina Doesch1, Achim Seeger1, Joerg Doering1, Tobias Hoevelborn1, Ulrich Kramer1, Michael Fenchel1, Andreas May1, Claus D. Claussen1, Stephan Miller1 1Eberhard-Karls-University of Tuebingen, Tuebingen, Germany

Myocardial stress perfusion MR imaging (MRSPI) at 1.5T is limited by low SNR. This can be compensated by an increase of field strength and contrast agent concentration. Aim of our study was the evaluation of MRSPI at 3T using a 1-molar contrast agent. MRSPI was assessed in 57 patients with suspected coronary artery disease (CAD) using a 2D sr GRE sequence (0.1 mmol Gadobutrol / kg BW). Standard of reference was invasive coronary angiography. Sensitivity for coronary artery stenoses >70% was 97%, specificity 81%, diagnostic accuracy 93%. MRSPI under such optimized conditions provides increased sensitivity / specificity for CAD.

13:30 2934. Myocardial Perfusion Quantification: Effects from Contrast Dose, Imaging Plane and Sequence Yi Wang1, 2, Raphael Hazel1, Bin Luo1, Marguerite Roth1, Jie Jane Cao1, Nathaniel Reichek1, 2 1St. Francis Hospital, Roslyn, New York, USA; 2SUNY, Stony Brook, New York, USA

The quantification of myocardial perfusion using MRI is an important research and clinical tool for evaluating ischemia. However, its dependence to contrast dosages, imaging sequences and imaging orientation has not been thoroughly investigated. We studied 14 normal volunteers using a dual bolus approach with 3 different sequences to acquire perfusion images in both long and short axis, and evaluated the regional absolute perfusion values. The objective of this study was to determine whether the resting perfusion quantification using the dual bolus approach is dependent on the MRI pulse sequence or imaging plane orientation.

14:00 2935. Value of First Pass Perfusion and Delayed Contrast Enhancemed MR Imaging in Detecting Microinfarction: Histopathologic Confirmation Marcus Carlsson1, David Saloner1, Alastair J. Martin1, Loi Do1, Juha Koskenvuo1, Maythem Saeed1 1University of California San Francisco, San Francisco, California , USA

Coronary microembolization is a frequent complication of coronary interventions. We determined the effects of microembolization on perfusion and visualization of microinfarction 1hr and 1week after delivery of embolic agents. First pass perfusion and delayed contrast enhanced (CE) MR imaging was used to non-invasively monitor the serial changes in regional perfusion and viability. Histopathology was used to confirm the presence of microinfarction. The embolic agents were visualized in coronary tree surrounded by microinfarction. Acute and subacute microinfarction showed perfusion deficit. CE-MR imaging delineated subacute microinfarction due to the loss of membrane integrity of ischemic myocytes, but not all discrete acute microinfarction.

14:30 2936. Multislice Single Shot Spin Echo EPI Perfusion Imaging with Zone-Selection and Parallel Imaging Pedro Ferreira1, Peter Gatehouse2, David Firmin1, Chiara Bucciarelli-Ducci1, Ricardo Wage2 1Imperial College, London, UK; 2Royal Brompton Hospital, UK

Myocardial perfusion images are often affected by a subendocardial Dark Rim Artifact (DRA). A sequence has been designed with the underlying ethos of greater robustness against the DRA, by reducing the echo train length and nulling the signal in the left ventricle blood pool. The sequence is a single-shot spin-echo EPI with zonal excitation and parallel imaging techniques. Preliminary results show no evidence of myocardial dephasing, or distortion by cardiac motion or field nonuniformity during first pass of contrast agent; although TSENSE is proving challenging to include with saturation recovery due to low SNR.

15:00 2937. Compressed Sensing Cardiac Perfusion Imaging Viton Vitanis1, Robert Manka1, 2, Urs Gamper1, Peter Boesiger1, Sebastian Kozerke1 1ETH Zurich, Zurich, Switzerland; 2German Heart Institute Berlin, Berlin, Germany

This work demonstrates the feasibility of accelerating perfusion imaging using Compressed Sensing and compares the method to k-t SENSE. Based on computer simulations and actual in-vivo measurements it is shown that Compressed Sensing yields lower reconstruction errors up to a net acceleration factor of three. Beyond this factor k-t SENSE outperforms with respect to root-mean-square reconstruction error. The lower error is, however, associated with some temporal low pass filtering of signal-intensity curves. In conclusion, both methods tested seem suitable to accelerate cardiac perfusion imaging up to net acceleration factors of five without compromising signal-intensity perfusion curves significantly.

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13:30 2938. First-Pass Cardiac Perfusion MRI with 50%-Reduced Contrast Agent Dosage Daniel Kim1 1New York University, New York, New York, USA

While first-pass cardiac perfusion MRI is a promising modality for the assessment of coronary artery disease, there are safety concerns associated with Gadolinium-based MRI contrast agents, especially in patients with renal insufficiency. One strategy to reduce the contrast agent dosage is to achieve maximal myocardial contrast-to-noise ratio (CNR) through pulse sequence optimization and trade off a portion of CNR to reduce the dosage. The purpose of this study is to optimize the pulse sequence with optimal k-space trajectory and variable flip angles to achieve comparable image quality at 50%-reduced dosage to that produced by a convention sequence at standard dosage.

14:00 2939. Perfusion Phantom for Quantitative Imaging Behzad Ebrahimi1, 2, Scott D. Swanson, Timothy E. Chupp, 2 1University of Michigan, Ann Arbor, USA; 2Focus Center, Ann Arbor, USA

A perfusion phantom with unique features and a wide variety of applications in MR and other imaging modalities is presented. The phantom is especially suited to tissue perfusion simulation with diffusible and non-diffusible MR tracers. A network of micro-channels in the scale of actual capillaries replicates the blood flow in tissues. Using microfabrication technique, networks with any desired pattern can be generated. Since the geometry of networks is known, flow rate, delay, dispersion and other fluid parameters can be exactly calculated, using finite elements numerical methods. These calculated results can be used to investigate the accuracy of experimental measurements and the precision of mathematical models.

14:30 2940. Quantitative Assessment of the Dark Rim Artifact in First Pass Perfusion Images: Effect of Stress and Rest, and Sequence Dependence Raphael Delano Hazel1, Nathaniel Reichek1, Yi Wang1 1St Francis Hospital, Roslyn, New York, USA

Dark Rim Artifact (DRA) in Gadolinium enhanced saturation recovery TrueFISP cardiac first pass perfusion images from normal volunteers collected during stress and rest, show similar frequency affecting 12.5% of the rest and 10.2% of stress images, with comparable severity represented by signal loss of 32.9 % (rest) and 31.5 % (stress) in the endocardium. The duration and severity of the DRA coincides with the maximum contrast agent concentration and susceptibility difference between LV and myocardium. A comparison of three pulse sequences shows that TrueFISP is most affected by the DRA, followed by TFL while EPI shows no artifact.

15:00 2941. The Relationship Between Signal Intensity and Myocardial Gadolinium Concentration for Three MR Perfusion Pulse Sequences: Implications for Measuring Absolute Myocardial Blood Flow Daniel C. Lee1, 2, Nils P. Johnson1, Kathleen R. Harris1 1Northwestern University, Chicago, Illinois, USA

Calculation of absolute myocardial blood flow from magnetic resonance first-pass perfusion studies by deconvolution requires a linear relationship between signal intensity (SI) and gadolinium concentration [Gd] in both the blood pool and the myocardium. We measured this relationship in canine myocardium for three common perfusion pulse sequences. Inversion recovery-prepared single-shot steady-state free-precession demonstrates excellent myocardial signal enhancement and a linear SI-[Gd] relationship. Saturation recovery-prepared segmented echo-planar-imaging and saturation recovery-prepared turbo fast low-angle shot exhibit less robust myocardial signal enhancement and a curvilinear SI-[Gd] relationship. This nonlinear signal response may result in underestimation of absolute myocardial blood flow.

Cardiac Diffusion Tensor Imaging Hall D Thursday 13:30-15:30

13:30 2942. Myofiber Developmental Plasticity in Fetal Hearts Delineated with Diffusion Tensor MRI Lei Zhang1, Junjie Chen1, Allyson Gibson1, Mark R. Holland1, Gregory M. Lanza1, Samuel A. Wickline1 1Washington University in St. Louis, St. Louis, Missouri, USA

Cardiac functions in prenatal and postnatal phases are different. We hypothesized that myocardial fiber structures in fetal hearts may also differ from that of the adult hearts. Diffusion tensor MRI was used to delineate myocardial fiber structures in fetal pig hearts. Balanced contributions from both left ventricle and right ventricles to the septal myofibers and a thick right ventricle free wall (RVFW) in fetal hearts were observed. In contrast, adult hearts showed thinner RVFW and a dominant contribution to the septal fibers from left ventricle. These structural differences may reflect the plasticity of myocardial fiber development in response to the programmed differential contractile functions before and after birth.

14:00 2943. A Study of Variability of the Mouse Myocardial Fiber Structure Obtained by MR Diffusion Tensor Imaging Yi Jiang1, Sarang Joshi2, Kumar Pandya3, Oliver Smithies3, Edward W. Hsu2 1Duke University, Durham, North Carolina, USA; 2University of Utah, Salt Lake City, Utah, USA; 3University of North Carolina, Chapel Hill, North Carolina, USA

Principal component analysis (PCA) was used to assess the variability of the mouse myocardial fiber helix angle and fractional anisotropy obtained by MR diffusion tensor imaging (DTI). Leave-one-out tests indicate that structural variability of the normal mouse hearts can be represented by as few as 6 DTI datasets. Moreover, PCA successfully distinguished hypertrophic hearts from the normal group. These findings suggest a rather low degree of intra-group variability and lend validity to atlas-based representation and modeling of the myocardial fiber structure.

14:30 2944. Diffusion Tensor MRI Reflects Age-Associated Changes in Normal and Cardiomyopathic Syrian Hamsters Wen Li1, 2, Allen Ye1, Ming Lu1, Suhanti Banerjee1, Xin Yu1 1Case Western Reserve University, Cleveland, Ohio, USA

The purpose of this study is to explore the potential of diffusion tensor MRI (DTMRI) in evaluating aging and cardiomyopathy (CM)-associated myocardial remodeling in Syrian hamsters. DTMRI were performed on formalin-fixed hearts of both normal and CM hamsters. Our results suggest that DTMRI is sensitive to microscopic structural changes associated with aging and disease progression.

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15:00 2945. Interspecies Variability in the Myocardial Fiber Structure Acquired Using MR Diffusion Tensor Imaging Lindsey Healy1, Sarang Joshi1, 2, Yi Jiang3, Edward Hsu1 1University of Utah, Salt Lake City, Utah, USA; 2Salt Lake City, USA; 3Duke University, Durham, North Carolina, USA

The variability in the fiber helix angle of mouse, rabbit, and sheep, obtained using MR diffusion tensor imaging (DTI), was assessed using principal component analysis (PCA). A significant difference was found between each of the rabbit and sheep hearts compared to the mouse hearts. The sheep and rabbit hearts were not significantly different. The significant difference between the rabbit and mouse and sheep and mouse hearts suggest that larger hearts cannot be directly scaled down to replace the structure of smaller animals.

Myocardial Viability Hall D Thursday 13:30-15:30

13:30 2946. Quantitative Assessment for Late Gadolinium Enhancement in Normal Myocardium Atsushi Kono1, 2, Naoaki Yamada1, Masahiro Higashi1, Suzu Kanzaki1, Teruo Noguchi1, Kazuro Sugimura2, Hiroaki Naito1 1National Cardiovascular Center, Suita, Japan; 2Kobe University Graduate School of Medicine, Kobe, Japan

Current assessment of delayed gadolinium enhancement in myocardium has limitation in detection of diffuse myocardial disease as based on relative signal intensity to the apparently non-enhanced myocardium. Normalization of myocardial signals by lumen signals in delayed enhancement (M/L) is useful to cancel out sensitivity inhomogeneity of surface coil. We demonstrate that normal M/L is invariable in a wide range of time after gadolinium administration, heart rate, hematocrit, and renal function (serum creatinine). On the basis of the results, M/L can detect abnormality of diffuse myocardial disease such as cardiac amyloidosis and Fabry disease.

14:00 2947. Three Dimensional Phase Sensitive Inversion Recovery (PSIR) TurboFLASH for Evaluation of Left Ventricular Myocardial Scar Aya Kino1, John Sheehan1, Sven Zuehlsdorff2, Peter Weale2, Xin Liu1, Randal Ramsey1, Renate Jerecic2, James Carr1 1Northwestern University, Chicago, Illinois, USA; 2Siemens Medical Solutions, Chicago, Illinois, USA

Delay enhanced (DE) imaging is a well-established method for detection of myocardial scar. 2D PSIR TurboFLASH is a widely accepted viability imaging technique and a 3D viability strategy, incorporating respiratory gating, have been shown to detect small myocardial scars compared to 2D approaches. The purpose of this study was to assess a 3D PSIR TurboFLASH imaging technique for detecting left ventricular myocardial scar and compare it to a conventional 2D PSIR TurboFLASH. This study demonstrated the navigator-gated 3D PSIR sequence shows equivalent results for the assessment of myocardial scar, quantitatively and qualitatively compared to routine segmented 2D-PSIR techniques

14:30 2948. Clinical Evaluation of Free-Breathing 3D Delayed Enhancement Imaging for Myocardial Viability Assessment: Comparison with Routine Breath-Hold 2D Imaging Thanh D. Nguyen1, Matthew D. Cham1, Pascal Spincemaille1, Martin R. Prince1, Jonathan W. Weinsaft1, Yi Wang1 1Weill Medical College of Cornell University, New York, New York, USA

The objective of this study was to prospectively compare a recently developed free-breathing navigator-gated 3D (3DNAV) delayed enhancement MRI (DE-MRI) with routine breath-hold (2DBH) DE-MRI in patients with confirmed myocardial infarction. 23 patients were imaged with both techniques at 1.5T. Compared to 2DBH imaging, 3DNAV imaging provided significantly better image quality in 33% less scan time. 2DBH and 3DNAV imaging identified 90 and 91 involved segments and 22 and 24 transmural segments, respectively. There were a strong correlation and narrow limits of agreement between the two techniques with respect to detected infarct volumes.

15:00 2949. LV Infarct Size and Peri-Infarct Zone Measurements: A Comparison of High Resolution 3D and Conventional 2D Late Gadolinium Enhancement Imaging Dana C. Peters1, Evan A. Appelbaum1, Reza Nezafat1, Yuchi Han1, Kraig V. Kissinger1, Beth Goddu1, Warren J. Manning1 1Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA

A high spatial resolution 3D late gadolinium enhancement sequence was used to image seven patients with prior myocardial infarction. The results show a clearer picture of scar morphology compared to 2D images, demonstrating features such as islands of viability, subendocardial infarcts not visualized on the 2D images, and improved papillary muscle scar detection. The scar volume by 3D correlated well with 2D measurement, but the peri-infarct zone was larger by 2D. This 3D higher spatial resolution imaging may be a step towards correlating infarct morphology with arrhythmias.

13:30 2950. Signal Intensity in Myocardial Scars Detected by Delayed-Enhancement MRI Differs in Subjects with and Without Previously Known Myocardial Infarction Raquel Espregueira Themudo1, 2, Lars Johansson1, 3, Charlotte Ebeling Barbier1, Lars Lind1, Håkan Ahlström1, Tomas Bjerner1 1Uppsala University Hospital, Uppsala, Sweden; 2Hospital Geral Santo António, Porto, Portugal; 3AstraZeneca, Gothenburg, Sweden

This study comprised signal intensity analysis of myocardial scars in delayed-enhancement Magnetic Resonance Imaging aiming to investigate if there was any difference between clinically recognized myocardial infarctions and clinically unrecognized myocardial scars. There was a significant difference between the signal intensity ratio between these 2 groups, suggesting that it might represent a difference in the scar tissue composition.

14:00 2951. Low Dose Dobutamine Adds Incremental Value to Delayed Enhancement Cardiac MR in the Prediction of Adverse Remodelling Following Acute Myocardial Infarction Anne Elizabeth Scott1, Scott Ian Semple1, Thomas Redpath1, Graham Hillis1 1Aberdeen University, Aberdeen, UK

The development of left ventricular dilatation in the months following acute myocardial infarction (AMI) is known as ‘adverse remodelling’ and confers a poor prognosis. Adverse remodelling is measured as changes in left ventricular end diastolic volume (LVEDV). We examined the relative utility of delayed enhancement (DE) and low dose dobutamine (LDD) CMR parameters, recorded 2 to 6 days post AMI, as predictors of changes in LVEDV six months later. LDD parameters added incremental value to DE parameters and were independently predictive of adverse remodelling.

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14:30 2952. Cardiac Phase-Resolved Acute Myocardial Infarct Imaging in Swines Rohan Dharmakumar1, Nirat Beohar1, Jain Mangalathu Arumana1, Zhouli Zhang1, Debiao Li1, 2 1Northwestern University, Chicago, Illinois, USA; 2Evanston, Illinois, USA

This work examines the feasibility of cardiac phase-resolved acute myocardial infarct imaging.Experimental studies performed in animals show that cardiac SSFP cine imaging can be used todetermine the presence of acute MI.

15:00 2953. Delayed Enhancement of the Peri-Infarct Border Zone is Significantly Affected by Partial Volume Averaging: Insights from Ex Vivo Rat Heart Images at a Near-Cellular Resolution Li-Yueh Hsu1, Erik B. Schelbert1, Stasia A. Anderson1, Bibhu D. Mohanty1, Syed M. Karim1, Peter Kellman1, Anthony H. Aletras1, Andrew E. Arai1 1National Institutes of Health, Bethesda, USA

We hypothesized that the intermediate signal intensity in the peri-infarct border zone between normal and infarcted myocardium maybe explained by partial volume averaging. Using 3D ex vivo rat heart MRI at an isotropic voxel resolution equivalent to 3 cardiomyocytes, we quantified the volume of peri-infarction on the acquired isotropic 3D high resolution images and on post-hoc slab averaged low resolution images.

13:30 2954. Detection of Recent Myocardial Infarction Using CINE SSFP Imaging James William Goldfarb1, Lenore Barhak1, Jing Han1 1Saint Francis Hospital, Roslyn, USA

In this study, use of conventional CINE SSFP imaging for the detection of myocardial edema resulting from recent MI was investigated. The signal behavior of infarcted and viable myocardium as well as the LV bloodpool was investigated as a function of cardiac phase to determine the image parameters for optimal imaging of myocardial edema. In CINE SSFP images, the LV bloodpool and myocardial signal intensities vary normally with cardiac phase. Myocardial edema can be best detected at the end of systole when its contrast with adjacent myocardium is the greatest.

14:00 2955. Fat/Water Separated Delayed Hyperenhanced (DHE) Myocardial Infarct Imaging James William Goldfarb1 1Saint Francis Hospital, Roslyn, USA

A three-point DIXON acquisition and reconstruction was combined with an inversion recovery gradient-echo pulse sequence. This allowed fat/water separation along with contrast-enhanced T1 sensitive delayed hyperenhanced myocardial infarct imaging. The technique was demonstrated in phantom experiments and subjects with chronic myocardial infarctions. Areas of infarction were well defined as conventional hyperenhancement in water images. Fatty deposition of myocardial infarction detected using this novel sequence was confirmed by precontrast opposed phase imaging.

14:30 2956. T2-Component of Conventional Cine SSFP Sequences is Sufficient to Detect Myocardial Edema in Patients with Acute Reperfused Myocardial Infarction Andreas Kumar1, Rohan Dharmakumar2, Jordin D. Green3, Jacqueline Flewitt1, Matthias G. Friedrich1 1University of Calgary, Calgary, Canada; 2Northwestern University, Chicago, Illinois, USA; 3Siemens Canada, Calgary, Canada

T2 spin echo sequences are commonly used to detect edema in acute myocardial infarction. Here, we show that the inherent T2 weighting of cine SSFP sequences used for functional imaging of the heart may be sufficient to detect edema. This may abolish the need for a dedicated T2 spin echo sequence in the imaging protocol for acute myocardial infarction.

15:00 2957. Improved Myocardial Viability Imaging with T2-Prepared Inversion Recovery (T2PREP-IR) Chia-Ying Liu1, Oliver Wieben1, Jean H. Brittain2, Scott Brian Reeder1 1University of Wisconsin-Madison, Madison, Wisconsin, USA; 2GE Healthcare, Madison, Wisconsin, USA

The clinical applications of delay-enhanced (DE) MRI using inversion recovery (IR) preparation are increasingly important for evaluation of myocardial viability. However, due to the similar T1 values of blood and infarcted tissue (MI), the contrast between the ventricular blood and subendocardial MI is often limited, adversely impacting the detection and evaluation of infarcted tissue. Exploiting differences between blood and myocardial T2, we propose a method that combines IR and T2 preparation into a single magnetization-prepared sequence (T2Prep-IR) to achieve T1 and T2 contrast within a single imaging acquisition to improve differentiation of enhancing subendocardial infarction and blood.

13:30 2958. Free-Breathing Delayed Contrast-Enhanced Three-Dimensional Viability MR Imaging of the Myocardium at 3T: A Feasibility Study Yasuo Amano1, Morimasa Takayama2, Yoshio Matsumura3, Yuriko Suzuki4, Shinichiro Kumita1 1Nippon Medical School, Tokyo, Japan; 2Sakakibara Memorial Hospital, Tokyo, Japan; 3Nippon Medical Schhol, Tokyo, Japan; 4Philips Medical Systems, Tokyo, Japan

Free-breathing delayed contrast-enhanced three-dimensional (3D) viability imaging of the myocardium at three-tesla (3T) magnetic resonance was compared with breath-hold two-dimensional (2D) viability imaging for assessments of CNR and extensions of damaged myocardium. A k-space weighted navigator and cardiac gating were used. This 3D imaging technique depicted 83.8 % of hyperenhancing myocardia with high CNR between hyperenhancing myocardium and blood and excellent agreement for transmural extension of the damaged myocardia (k = 0.875). Free-breathing delayed contrast-enhanced 3D viability imaging was feasible for the evaluation of the hyperenhancing myocardium at 3T.

14:00 2959. Simulation of Artificial Delayed Hyperenhancement Resulting from Signal Modulation in the Phase Encoding Direction Amol S. Pednekar1 1Philips Medical Systems, Bothell, Washington, USA

An artificial mid-spetal hyperenhancement often appears on the inversion recovery prepared interleaved segmented gradient recalled echo (IRISGRE) sequence with a low-high phase encoding order. In this simulation we studied the imaging artifacts resulting due to the signal modulation across the phase encode direction in the IRISGRE sequence. These hyperenhancement artifacts capable of leading to the spurious diagnosis of myocardial scarring, can be avoided by using liner phase encoding order.

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14:30 2960. T1 Pulse Sequence Optimization in a Diabetic Cohort Warren Foltz1, Kim Alexander Connelly1, 2, Venkat Ramanan, Gideon Paul1, Graham Wright1, Alexander Dick1 1Sunnybrook Health Sciences Centre, Toronto, Canada; 2St Michael's Hospital, Toronto, Canada

Quantitative MRI measurements of left ventricular remodeling have the potential to facilitate earlier diagnosis and allow therapeutic monitoring of patients with diabetic cardiomyopathy. The Gd-DTPA partition coefficient or λ, defined as the tissue-to-blood ratio of extra-cellular volume fractions, should be valuable because changes in λ from control values of 0.3 reflect alterations in the extra-cellular volume, such as that seen in pathological ventricular remodeling. We performed quantitative λ measurements within a diabetic cohort using a cardiac-gated but free-breathing single-point spiral T1prep strategy. Mean λ appears to be elevated to 0.44 from control levels. The spiral methodology appears to provide reproducibility in global λquantification which is on the order of 10%, which is the sensitivity target for monitoring diabetic remodeling.

15:00 2961. Myocardial T1ρ Mapping at 3T Using a Novel Spin-Locking Technique Benjamin Edward Northrup1, 2, Xiang He1, Kyle Stephan McCommis1, Jie Zheng1 1Washington University School of Medicine, St. Louis, USA; 2Dartmouth Medical School, Hanover / Lebanon, USA

A new spin-locking technique was used in conjunction with segmented gradient-recalled echo and TrueFISP acquisitions on a 3T MRI system to acquire cardiac T1-weighted images in a single (~20 second) breath-hold. This facilitated the calculation of single-section myocardial T1ρ maps with minimal intra-scan motion artifacts. No significant difference between GRE and TrueFISP myocardial T1ρ signal values was observed. No difference in T1ρ values among the three spin-locking frequencies was observed. This study provided baseline myocardial T1ρ mapping data in normal subjects, which will be useful for the evaluation of myocardial function with T1ρ techniques in the future.

Safety: Acoustic Noise Hall D Monday 14:00-16:00

14:00 2962. Experimental Reduction of Acoustic Noise Through Cancellation of Impulsive Forces Xin Chen1, Xingxian Shou1, Jamal J. Derakhshan1, Shmaryu M. Shvartsman, 12, Jeffrey L. Duerk1, 3, Robert W. Brown1 1Case Western Reserve University, Cleveland, Ohio, USA; 2Hitach Medical Systems, Twinsburg, Ohio, USA; 3University Hospitals, Cleveland, Ohio, USA

MRI acoustic noise is a long-standing problem exacerbated by higher field strengths and faster imaging. We investigate the idea of using the impulsive forces produced by gradient ramping to cancel each other. Guided by string simulations, we conduct experiments to test pulse sequences incorporating these cancellations. As examples of appropriate timings, combinations of trapezoid or “quadratic” pulses or pairs of trapezoids are shown to cancel three frequencies and their harmonics. All results are in good agreement with the simulations and Fourier theory. A rich variety of possibilities in sequence design, including the TR freedom, may be optimized for noise control.

14:30 2963. Analysis of Acoustic Noise Transfer Function in MRI: Multi-Center Trial Takashi Hamaguchi1, Tosiaki Miyati2, Masaya Hirano3, Yasuhiro Fuziwara4, Hirohiko Kimura4, Hiroyasu Takeda5, Yasuo Takehara5, Kenro Nagashima6, Yuriko Suzuki6, Jousei Ueda2 1Kanazawa University Hospital, Kanazawa, Japan; 2Kanazawa University, Kanazawa, Japan; 3GE Medical Systems, Hino, Japan; 4University of Fukui Hospital, Japan; 5Hamamatsu University School of Medicine, Japan; 6Philips Medical Systems, Japan

We determined a gradient-pulse-to-acoustic-noise transfer function (GPAN-TF) at various MRI centers. We measured sound pressure levels in the frequency domain in six clinical super-conducting MRI systems, and calculated a GPAN-TF in each gradient coil. GPAN-TF at a high frequency range was larger than that at low frequency for all MR scanners. For high frequency, the 3.0-T MR scanner had a larger GPAN-TF than that of 1.5-T. MR scanner with a vacuum chamber reduced GPAN-TF at a lower frequency. GPAN-TF analysis enables to obtain more detailed information on acoustic noise properties independent of pulse sequences or imaging parameter in MR scanner.

15:00 2964. Experimental Study of Active Acoustic Noise Control with MRI Compatible Headphones and Microphones in a 4T MRI Scanner Jing-Huei Lee1, Brent W. Rudd1, Mingfeng Li1, Jeffrey Osterhage1, Teik C. Lim1 1University of Cincinnati, Cincinnati, USA

Typical speakers and microphones utilizing magnetic components are unable to be used in the vicinity of the MRI scanner. In this study, we reproduced MRI noise in a sound quality chamber while measuring SPL and running a feed-forward control system targeting one of the dominant frequencies. The noise reduction performance of a high fidelity headphone/microphone containing magnetic components is compared with an MRI compatible combination utilizing piezoelectric speakers and an optical microphone. In this report, the results from the sound quality chamber show that the MRI compatible system produces results that are comparable to that of the high fidelity system.

15:30 2965. Sound Pressure Level Prediction of Arbitrary Sequences Sebastian Schmitter1, Lothar Rudi Schad2 1German Cancer Research Center, Heidelberg, Germany; 2University of Heidelberg, Mannheim, Germany

During MR image acquisition huge sound pressure levels are generated, which can tamper the results of auditory fMRI experiments. A prediction of the generated acoustic noise and its spectrum is necessary in order to adapt auditory stimuli to the scanning sequence. In this work the linearity between gradient amplitude and sound pressure is verified in a wide range between 60 and 115dB. This linearity is exploited in a simulation program which predicts the SPL of an arbitrary sequence. A loud and a silent sequence were exemplarily simulated, the results deviate only 1.8dB from the measured values.

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Safety: Implants & Devices Hall D Tuesday 13:30-15:30

13:30 2966. An Evaluation of the Potential Extent of Catheter Heating During MR Imaging Alastair Martin1, Bryant Baek2, Gabriel Acevedo-Bolton2, Randall Higashida1, John Comstock2, David Saloner1, 2 1University of California, San Francisco, California , USA; 2San Francisco VA Medical Center, San Francisco, California , USA

An obstacle to the incorporation of MR methods in endovascular procedures is the potential for focal heating near catheters and guidewires. This study investigated the magnitude of heating near endovascular devices in a tissue mimicking phantom. A fiber-optic temperature sensing system was used to measure temperature changes in an assortment of geometric conditions and with SAR levels up to 4W/kg. Heating was found to be amplified near these devices and was a function of immersed device length, position within the bore, and SAR. SAR limits are proposed as sufficient for safely imaging catheterized patients without concern for thermal injury.

14:00 2967. MR Safety and Compatibility of Cardiac and Peripheral Stents at 7T Ivan Emilov Dimitrov1, 2, Aman Haider3, Emmanouil Brilakis2, Subhash Banerjee3, Craig Malloy2, 3 1Philips Medical Systems, Cleveland, Ohio, USA; 2University of Texas Southwestern, Dallas, Texas, USA; 3Dallas VA Medical Center, Dallas, Texas, USA

We investigated the magnetic interactions (translational attraction, torque), RF heating, and artifact levels for five coronary and four peripheral stents (Express, Cypher, Ultra, Palmaz are made of stainless steel; Vision, Driver - cobalt chromium; Sentinol, Precise - nitinol) at 7T. With the exception of Palmaz, all stents showed deflection less than 45 degrees. All stents exhibited no torque and insignificant RF heating (0.1 – 0.2 0C). Artifact levels were different for the different stents, all of them creating a void few times their geometrical sizes. All stents, with the exception of the large stainless steel Palmaz, are MR safe at 7T.

14:30 2968. Evaluation of RF and Resistive Heating of Magnetically- Assisted Remote Control (MARC) Steering Coils in Endovascular Interventional MRI Fabio Settecase1, Timothy P. L. Roberts2, Walter Kucharczyk3, Steven Hetts1, Mark Wilson1, Ron Arenson1 1University of California San Francisco, San Francisco, California , USA; 2Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA; 3University of Toronto, Toronto, Canada

Catheters can be steered in interventional MRI using magnetic moments induced by applying current to orthogonally arranged wire coils at a catheter tip. Nonferromagnetic conducting wires, however, can cause significant radiofrequency (RF) heating in MRI. This study demonstrates, in a worst case scenario without convective blood flow, RF-induced temperature increases using a MARC-steered catheter are less than 1ºC after 15 min of real-time MRI. Physiologically significant resistive heating (greater than 4ºC) occurs only above 200 mA for 30 s in multiple coils. MARC steering may be an attractive alternative to catheter navigation with heating safety concerns arising only at higher currents using this prototype.

15:00 2969. MR-Safety and Compatibility of Silver Based Wound Dressings at 7T Steffen Sammet1, Zaid Chaudhry1, William TC Yuh1, Rebecca Coffey1, Andrew Crockett1, Sidney Miller1, Michael Vincent Knopp1 1The Ohio State University, Columbus, USA

The purpose of this study was to determine whether silver based wound dressings are compatible with MRI imaging by investigating if ultra high field MRI and silver based dressings produce either increased body surface temperature and/or caused distortions in the resulting MR image. All tested silver containing wound dressings are both safe and compatible with MRI at 7T.

RF Receive Coils Hall D Wednesday 13:30-15:30

13:30 2970. Reduction of SNR Losses Due to RF Coil Coupling Via Coil Current Sensing Randy Duensing1 1Invivo Corporation, Gainesville, Florida, USA

This method employs a new paradigm in multi-channel RF coils in which coupling (in moderate amounts) is not detrimental as long as it is measurable, thus permitting algebraic inversion. Two preamplifiers are utilized in each loop, one preamplifier with the impedance mismatched used to provide inductive decoupling, but the other matched to produce minimal impact on the loop impedance. This second non-damping preamplifier measures the residual current in the loop and therefore a model of voltage coupled in other nearby coils. Utilization of this additional signal improves the SNR over standard methods when the coupling is moderate.

14:00 2971. Transmission Line Effects on the Noise Correlation Matrix for Multiple RF Coils Ryan Brown1, 2, Yi Wang1, 2 1Weill Medical College of Cornell University, New York, USA; 2Weill Graduate School of Medical Sciences of Cornell University, New York, USA

The original noise correlation formula derived by Redpath showed correlation depends on the real part of the impedance matrix. In this work, we introduce a more generalized formula to include effects from transmission lines and preamplifier impedance mismatch. This formula is used to calculate correlation between two-channel circuits connected to preamplifiers using several transmission line lengths. The calculated correlation matches well with that measured on the MR scanner and suggests transmission line length can be utilized as an additional degree of freedom for coil decoupling, and can be adjusted to achieve zero noise correlation.

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14:30 2972. An Eigenvalue/eigenvector Analysis of Decoupling Methods and Its Application at 7T MR Imaging Zhentian Xie1, Xiaoliang Zhang1, 2 1UC San Francisco, San Francisco, California , USA; 2UCSF/UC Berkeley Joint Graduate Group in Bioengineering, San Francisco & Berkeley, California , USA

this work, we report an eigenvalue/eigenvector analysis method for designing non-overlapped coil arrays and one of its immediate applications as a novel decoupling method. The proposed microstrip array coil for 7T MRI, consisted of 2 microstrip resonators and one microstrip decoupling line, was built on a Teflon cylinder. Bench test and preliminary imaging results show that the proposed design provides a robust approach to design of parallel imaging arrays at ultrahigh fields.

15:00 2973. An 8-Channel Microstrip Array Coil for Mouse Parallel MR Imaging at 7T by Using Magnetic Wall Decoupling Technique Zhentian Xie1, Xiaoliang Zhang1, 2 1UC San Francisco, San Francisco, California , USA; 2UCSF/UC Berkeley Joint Graduate Group in Bioengineering, San Francisco & Berkeley, California , USA

We present an 8-channel microstrip array coil for mouse studies at 7T. The decoupling strategy of using microstrip resonators was employed as adjustable magnetic walls in order to block couplings between coil elements. Different from some decoupling methods for non-overlapping design, the magnetic wall method has no physical connection between the coil elements and the decoupling elements, theoretically this method is not frequency-sensitive. Therefore the decoupling performance can be maintained in a broad frequency range. The Preliminary MR images indicate the effectiveness of the proposed magnetic wall decoupling technique at the ultrahigh field of 7T. The proposed coil array provides a robust approach to design of parallel imaging arrays at ultrahigh fields.

13:30 2974. An 8-Channel Non-Overlapped Spinal Cord Array Coil for 7T MR Imaging Zhentian Xie1, Xiaoliang Zhang1, 2 1UC San Francisco, San Francisco, California , USA; 2UCSF/UC Berkeley Joint Graduate Group in Bioengineering, San Francisco & Berkeley, California , USA

In this report, we designed and constructed an 8-channel non-overlapped surface coil array using with strong decoupling performance and good coverage for spine parallel imaging. Different from conventional decoupling methods for non-overlapping design such as the method using lumped L/C decoupling circuits , we use a new magnetic-wall decoupling method to decouple the resonant elements. The magnetic wall is generated by the microstrip circuits positioned between two adjacent surface coil elements. Without physical connection between the decoupling microstrip and array elements, theoretically this method is not frequency-sensitive. Therefore the decoupling performance can be maintained in a broad frequency range. Bench test and preliminary imaging results are shown using the proposed coil array at 7T.

14:00 2975. Investigation of Liquid Nitrogen Cooled Coils for Low Field MR Imaging Hoon-Sin Cheong1, Ivo Volkov2, Eugeny Krjukov1, Neil Alford3, Chris Randell4, Jim Wild1, Martyn Paley1 1University of Sheffield, Sheffield, UK; 2London South Bank University, London, UK; 3Imperial College London, London, UK; 4Pulseteq Ltd., Gloucester, UK

Images have been acquired using a specially designed cryostat and a liquid nitrogen cooled copper coil on a dedicated 0.17T neonatal/orthopedic imaging system. A factor of 1.4 improvement in SNR was obtained. Future work will compare the cooled copper coil with an identical geometry HTSC coil.

14:30 2976. Double Loop-Asymmetric Saddle Coil Arrays Optimized for Spine and Torso Imaging Pei H. Chan1, Dan Spence2, Vincent Chen1, Piero Ghedin2 1GE Healthcare Coils, Aurora, USA; 2GE Healthcare, Milwaukee, USA

In this abstract we present a double loop-asymmetric saddle (DLAS) coil array configuration which has two highly overlapped asymmetric saddle coils in the middle and two loop coils on the sides. The overlap and quadrature nature between the two asymmetric saddle coils result in significant SNR improvement at the spine region. A 3.0T posterior array coil built with multiple DLAS blocks has demonstrated better SNR than a 3.0T 8-channel cervical-thoracic-lumber coil for spine imaging as well as good parallel imaging capability for torso imaging.

15:00 2977. A Modular Approach to Large Arrays Using Stacked Segments Wolfgang Driesel1, Harald E. Möller2 1Max Planck Institute for Human Cognitive and Brain Sciences , Leipzig, Germany; 2Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany

We propose a stacked combination of loop coils and microstrip transmission-line elements (MTL), which are intrinsically orthogonal, to obtain a large number of coil segments. In a first prototype a 32-channel array based on 16 stacked segments was tested. Experimental results indicate, that array coils with a large number of segments and excellent decoupling between segements can be designed from stacks of MTLs plus one or more loop-structures consisting of one or more loops. Simulations indicate a potential for parallel imaging with acceleration in z-direction.

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RF Transmit Coils & Calculations Hall D Wednesday 13:30-15:30

13:30 2978. Characterization of a Novel 8 Channel Microstrip Head Array at 7 T – Numerical Simulation and Experimental Verification Achim Bahr1, Stefan Orzada1, Thomas Bolz1 1IMST GmbH, Kamp-Lintfort, Germany

Microstrip resonators are interesting basic elements for the design of RF volume coils at high frequencies. In this work we describe a novel 8 channel microstrip array at 7 T which provides good B1-Field homogeneity in combination with decreased mutual coupling. The novelty implemented in this coil is the use of meander line structures at both ends of the coil elements. Low mutual coupling is verified by S-parameter measurements. In addition simulation and measurement results of the B1-Field and SAR are shown.

14:00 2979. A Novel 7 T Microstrip Element Using Meanders to Enhance Decoupling Stephan Orzada1, Achim Bahr1, Thomas Bolz1 1IMST GmbH, Kamp-Lintfort, Germany

In this work we describe a novel method to distinctly increase the decoupling of neighbouring microstip elements at 7 T. The novelty implemented in these coil elements is the use of meanders at both ends.Symmetrically fed elements with different numbers of meanders are compared to a symmetrically fed stripline element without meanders via simulation and measurement.While longitudinal homogeneity remains the same, decoupling between neighbouring elements is increased by up to 10 dB. Penetration depth, absolute field strength and separation between neighbouring sensitivities are improved. Therefore meander elements are superior compared to standard microstrip lines concerning the use of parallel transmit and receive techniques.

14:30 2980. Worst Case SAR Scenario as a New Metric for SAR Analysis in B1 Phase Shim Xiaoping Wu1, Tsung-Hui Chang1, Zhi-Quan Luo1, Can Akgun1, J. Thomas Vaughan1, Kamil Ugurbil1, 2, Pierre-Francois Van de Moortele1 1University of Minnesota, Minneapolis, Minnesota, USA; 2Max Planck Institute for Biological Cybernetics, Tübingen, Germany

It has been shown numerically and experimentally that B1 shim can efficiently address transmit B1 (B1+) inhomogeneity (1). However, the risk of increasing specific absorption rate (SAR) deposition with RF manipulation is a major concern especially at very high magnetic field. The impact of B1 shim on SAR has been considered but it remains difficult to compare SAR maps obtained with multi-transmit RF coils with a variety of phase and amplitude inputs. Here we propose a new metric, "pixel-wise worst case SAR scenario", to be used as a reference when comparing SAR for different B1 shim solutions. Computing this reference, based on electromagnetic models, consists of finding the maximum E2 value for each pixel for all of possible B1 input complex values. We propose a fast computational solution for solving this nonconvex optimization problem, and we apply this method to generate E2 maps for 16-channel RF coils at 7 T.

15:00 2981. An Inexpensive and Programmable Separated Coil CASL System Qin Xu1, Lei Zhou1, Christopher Glielmi1, Kisueng Choi, Xiaoping Hu1 1Georgia Institute of Technology/Emory University, Atlanta, Georgia, USA

A low-cost and programmable design for two-coil continuous arterial spin labelling system with minimal scanner hardware modifications is presented. A system-on-chip direct digital frequency synthesizer is chosen to generate the RF without sacrificing signal performance. This system offers remote control and programmable capabilities for easy setup and debugging of the perfusion. Performance of this system for CASL is demonstrated experimentally.

RF Receive Coils: Dual Tuned & Microstrip Hall D Wednesday 13:30-15:30

13:30 2982. A Theoretical Study on the Frequency Modes Separation of Double Tuned TEM Resonators Assunta Vitacolonna1, Marcello Alecci1 1University of L'Aquila, L'Aquila, Italy

The poor high field mode separation in double tuned TEM Resonators, can produce shading artifacts when the TEM is loaded with human tissue. In this work we show theoretically that a suitable design and geometrical disposition of the coaxial elements allows a significant increase of the high frequency resonant modes splitting.

14:00 2983. A Novel Double-Tuned Head Coil with 16 Double-Tuned Elements for 7T MRI/S Chunsheng Wang1, Bing Wu1, Duan Xu1, Xiaoliang Zhang1 1University of California San Francisco, San Francisco, USA

A Novel double-tuned head coil with 16 double-tuned elements was designed and tested successfully at 7T. Resonant modes at both low frequency and high frequency are well-defined at bench test. This kind of structure can provide almost identical B1 field distribution for both 13C MRS and 1H MRI because of identical symmetric of elements for both nuclei.

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14:30 2984. Design of Quadrature Microstrip Transmission Line (MTL) Volume Coil for Cat MRI/fMRI Application at 9.4T Ye Li1, 2, Xiaohong Zhu2, Yi Zhang2, Xiaohua Jiang1, Wei Chen2 1Tsinghua University, Beijing, People's Republic of China; 2University of Minnesota, Minneapolis, USA

The ability to scan entire cat brain is important to investigate large-scale neural networks. A new design of MTL volume coil integrated with head holder for the whole cat brain MR imaging has been presented. A prototype coil was developed and constructed using 16 MTL resonant elements. The mineral oil images and in-vivo cat brain images were acquired for coil test and validation. The preliminary images suggest that the MTL volume coil provides good homogeneity and sensitivity in the entire cat brain. Moreover, the coil is superior for investigating brain functions, in particular, in deep brain regions, showing a clear thalamocortical visual network connecting LGNs and V1 in the cat brain.

15:00 2985. A Novel Dual-Frequency Volume Coil Using Common Mode/differential Mode (CMDM) Resonators at 7T Zhentian Xie1, Xiaoliang Zhang1, 2 1UC San Francisco, San Francisco, California , USA; 2UCSF/UC Berkeley Joint Graduate Group in Bioengineering, San Francisco & Berkeley, California , USA

In this work, we applied common mode and differential mode concepts to design dual frequency volume coil designs. Common mode and differential mode (CMDM) exist within two coupled parallel transmission lines, yielding two current distributions and magnetic radiation fields. At the common mode, the two currents on a resonator are identical. At the differential mode, the currents are opposite to form a loop on that resonator. Both currents and magnetic fields in a CMDM resonator are isolated between two modes. Therefore, these modes could be designed independently at two resonant frequencies without any interference. Based on CMDM algorithm, we presents a dual tuned carbon-proton volume coil working in 7T MR system. The volume coil had 8 CMDM elements with the 75MHz and 298.14MHz operating frequencies for in vivo 13C/1H MRI/S studies at 7T. Preliminary results from a corn oil phantom were acquired using the proposed coil at 7T. Based on the preliminary results on bench test and MR scans, dual-tuned microstrip volume coil with CMDM resonant elements is feasible, provided that sufficient radial separation is maintained between the strip conductor and the ground to provide sufficient coupling between corresponding elements. The proposed design may provide a simple approach to dual-tuned volume coil design for in vivo multinuclear MR at ultrahigh fields.

Systems, Subsystems & Hybrid Systems Hall D Thursday 13:30-15:30

13:30 2986. Development of a Combined MicroPET®/MR System Rob C. Hawkes1, Alun J. Lucas1, Richard E. Ansorge1, Stefan B. Siegel2, Robert Nutt2, John C. Clark1, Tim D. Fryer1, T Adrian Carpenter1 1University of Cambridge, Cambridge, UK; 2Siemens Molecular Imaging, Knoxville, Tennessee, USA

We have constructed a combined microPET®/MR system. This system delivers a complete PET detector ring of diameter 15cm and axial field of view 7.8cm for simultaneous PET/MR, with the unique facility to apply conventional PET-based attenuation correction for validation of MR-based techniques. We have previously reported detector module performance, and a 'dual module' PET/MR interaction study. Here we report on assembly and initial tests of the complete PET/MR system.

14:00 2987. Study of the Magnetic Interaction of a 4-Coil Array and Copper Shielding with a PET/MRI Using the Finite-Element Method Sergio Enrique Solis1, Dardo Tomasi2, Alfredo Odon Rodriguez1 1UAM Iztapalapa, Mexico, Mexico; 2Brookhaven National Laboratory, Upton, New York, USA

A single imaging modality cannot provide information both structure information and function. The combination of PET and MRI offers tantalizing opportunities, with important challenges. Cross talk between the MRI transceiver and the PET digital electronics can lead to interfering RF noise in both imaging modalities. An electromagnetic shielding, decoupling the PET and MRI systems, must be tightly located between the RF coil and the PET scintillating crystals to minimize this interference without loosing sample space. We numerically studied the behaviour of a 4-coil array for a PET-MRI system. This is mainly motivated by the advantages offered by MRI parallel imaging.

14:30 2988. Understanding Acoustic Noise Suppression with Gradient Design: a Vibrating String Model Xin Chen1, Xingxian Shou1, Timothy P. Eagan1, 2, Robert W. Brown1 1Case Western Reserve University, Cleveland, Ohio, USA; 2Present address: Philips Medical Systems, Highland Heights, Ohio, USA

Gradient acoustic noise in MR scanners has long been a concern for patient comfort and, on occasion, hearing safety. We apply a forced damped vibrating string system to model sets of individual frequencies found in the coil response spectrum. The general string solution accounts for previous experiments on peak cancellation, provides a physical basis for understanding these results, is a robust embodiment of a linear response system, and offers a new approach to active noise suppression. The method opens up a number of different pulse profiles and combinations that can be used to attenuate important contributions to the acoustic spectrum.

15:00 2989. Ultra-Short Echo Time Imaging Using an Independent Spectrometer and Coil Insert Martyn Paley1, Eugeny Krjukov1, Michael Lamperth2, Ian Young2 1University of Sheffield, Sheffield, UK; 2Imperial College, London, UK

Short echo time and repeat time sequences have been implemented and tested on an independent spectrometer and gradient/RF coil insert. Echo times a short as 10 microseconds for a radial sequence and repeat times as short as 680 microseconds for a 2D gradient echo sequence have been demonstrated.

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13:30 2990. The Design of Planar Transverse Gradient Coils Using a Deformation Algorithm Minhua Zhu1, Feng Liu2, Ling Xia1, Andrew Mehnert2, Hector Sanchez Lopez2, Qing Wei2, Stuart Crozier2, Jianfeng Zhu1, Zhaoyang Jin1 1Zhejiang University, Zhejiang, People's Republic of China; 2University of Queensland, Brisbane, Australia

In this work we have proposed an efficient real-space method for the design of bi-planar gradient coils for open MRI systems. The algorithm can be used for complicated gradient coil design through an appropriate parameterization of the current arcs. It represents each arc by a closed contour described by parametric equations such that the ensemble of closed contours can be deformed/reshaped in a simple manner controllable by just a few parameters. These parameters are then used to define system rearrangements in the design procedure. An iterative optimization procedure is used to adjust the control parameters to minimize target/cost functions including gradient homogeneity, inductance and other parameters. The given planar transverse coil example demonstrates the capability of the proposed deformation-space methodology.

14:00 2991. A New Shimming Approach Using the Equivalent Magnetizing Current (EMC) Method Hector Sanchez Lopez1, Feng Liu1, Adnan Trakic1, Ewald Weber1, Stuart Crozier1 1University of Queensland, Brisbane, Australia

This paper presents a new alternative shimming procedure to correct the magnetic field inhomogeneities generated by horizontal and C-shape biplanar MRI magnets. A magnetization map obtained through the application of the Equivalent Magnetizing Current (EMC) method is used to define the domain where the discrete iron shim set is placed to generate a given field harmonic [1]. Optionally, instead of iron a current pattern is used, then the magnetization is related to the stream function (SF) and the current pattern is placed at equally spaced contours of the SF [1]. If a set of discrete iron pieces with no reversible magnetization direction is employed to mimic the continuous magnetization function (MF) map, then iron shims of unit strength are placed only in the positive domain (valid domain) of the MF map. The field source matrix is calculated only for the discrete elements located in the valid domain, which leads to a better conditioned matrix and superior solutions. An LP algorithm is used to calculate the optimal thickness and location of the discrete ferroshims to produce the target harmonics. Examples of simulated shimming of horizontal/C-shape magnets are presented. In the case of permanent open magnets, the magnetic coupling among the iron pieces and its influence over the magnetic field harmonics is studied for linear and nonlinear iron cases. The influence of the selection and arrangement of individual shim sizes over the field source matrix conditioning is also analysed.

14:30 2992. Generalized Two-Dimensional Orthogonal Spatial Encoding Fields Gerrit Schultz1, Anna Welz1, Jürgen Hennig1, Maxim Zaitsev1 1University Hospital Freiburg, Freiburg, Germany

Orthogonality of the gradient fields is crucial to good image quality using non-bijective, curvilinear spatial encoding fields. Often it is advantageous to apply a linear z-gradient along with a pair of nonlinear encoding fields. We present a simple method capable of finding all possible mutually orthogonal fields for this actual two-dimensional encoding situation.This can be achieved by defining the encoding fields to be the real and the imaginary part of any holomorphic function. The presented approach is flexible in the design of fields for specialized applications and its simple mathematical structure allows numerical accessibility to general optimal design formulations.

15:00 2993. Cardiovascular MRI in Mice in Vivo at 9.4T with a 1500 MT/m (150 Gauss/cm) Actively Shielded Gradient Coil Guangping Dai1, Kai-Ming Lo2, Shuning Huang1, Piotr Starewicz2, David Sosnovik 1 1Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA, 2Resonance Research, Inc.

A novel 1500 mT/m gradient coil has been constructed for cardiac MRI in mice at 9.4 T. Echo times of 1 ms and less can be obtained with this coil allowing fine cardiovascular structures to be imaged with a new level of clarity and resolution.

MR-Guided Interventions (Non-Thermotherapy) Hall D Monday 14:00-16:00

14:00 2994. Magnetic Resonance Delivery and Monitoring of Empty MR Visible Capsules: Long Term Follow-Up David Arthur Woodrum1, Wesley D. Gilson2, Thomas Link2, Li Pan2, Christine H. Lorenz2, Di Qian2, Brad P. Barnett2, Dara L. Kraitchman2, Jeff WM Bulte2, Aravind Arepally2 1Mayo Clinic, Rochester, Minnesota, USA; 2Johns Hopkins University School of Medicine, Baltimore, Maryland, USA

Cell microencapsulation provides immuno-protection where individual cells are surrounded with a thin shell that is impermeable to antibodies but is permeable to small molecules. However, basic questions for long-term implantation of clinical dose of magnetocapsules (140,000) into the portal vein need to be addressed. Therefore, in this survival study, five swine underwent MR guided transplantation with 140,000 empty magnetocapsules as a first step towards the goal of delivering encapsulated cells as therapy. All animals survived the procedure and were followed for 4 weeks. Magnetocapsules were intact at four-week follow-up without disruption or change in distribution.

14:30 2995. Marked Microspheres Assessment Using 1.5T Scanner for Embolization Follow Up Hassan Jassar1 1Université de Technologie de Compiègne (UTC), Compiègne, France

Controlled embolization with MRI remains challenging due to the abscence of effective detection with another imaging modality. 4 sizes SPIO loaded microspheres were injected into 8 ex vivo sheep kidneys or were embedded in a hydrogel as different grouping. The feasibility of in vivo assessment was determined according to coils, FOV, and sequence. Marked microspheres appeared as black spots, a strong linear correlation between apparent and real sizes of microspheres regardless their number, a positive visualization in in vivo condition. Our methods demonstrate the efficiency of marked microspheres assessment, in vitro and in vivo conditions, with MRI according to different sizes.

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15:00 2996. MR Assessment of Vasospasm Severity and the Impact of Endovascular Therapy Alastair Martin1, Nerrisa Ko1, Randall Higashida1, Adrian Gelb1, Max Wintermark1, Van Halbach1, Christopher Dowd1, David Saloner1 1University of California, San Francisco, California , USA

An XMR suite is used to evaluate endovascular therapies aimed at patients suffering from cerebral vasospasm. Vasospasm usually occurs secondary to subarachnoid hemorrhage and can result in delayed infarction if not properly treated. Present methods for diagnosing and treating the condition have limitations and therefore we explored the utility of augmenting endovascular treatment with MR assays including quantitative flow and perfusion. An increase in bulk flow following therapy was evident even with substantially lower post-procedure mean arterial pressure. Abnormalities in perfusion timing maps resolved following therapy and a global increase in rCBF was evident.

15:30 2997. Phantom and Clinical Validation of 3T MRI for Gamma Knife® Radiosurgery Treatment Planning Beibei Zhang1, Derek MacFadden2, Andrei Z. Damyanovich1, Marcus Rieker3, Kristy K. Brock1, Mojgan Hodaie4, Normand Laperriere1, Michael Schwartz4, May Tsao1, Jeffrey Stainsby5, David A. Jaffray1, Mark Bernstein4, David Mikulis6, Cynthia Ménard1 1Princess Margaret Hospital, Toronto, Canada; 2University of Toronto, Toronto, Canada; 3Physikalisch-Technische Gesellschaft für Radiologie mbH, Tübingen, Germany; 4Toronto Western Hospital, Toronto, Canada; 5GE Healthcare, Mississauga, Canada; 6University Health Network, Toronto, Canada

MRI is central to Gamma Knife® (GK) Radiosurgery (RS) treatment planning. In this study we explored the validity of using 3T MRI for GK RS planning. Geometric accuracy measured in fiducial reference deviations and anatomic landmark displacements yielded comparable results for 3T and 1.5T MRI. Inter- and intra-observer study on target volume definition and treatment isocenter placement also yielded similar results in spatial congruency. Hence we have demonstrated that 3T MRI is valid for GK RS planning under the imaging conditions investigated, but did not demonstrate an improvement in observer reproducibility despite a subjective improvement in image quality.

14:00 2998. Identification of the Pyramidal Tract Using Neuronavigation Based on Intraoperative DWI and Subcortical Stimulation Norihiko Ozawa1, 2, Yoshihiro Muragaki1, Hirokazu Suzukawa3, Ryoichi Nakamura1, Hiroshi Iseki1 1Tokyo Women's Medical University, Tokyo, Japan; 2Hitachi Medical co., Chiba, Japan; 3Infocom co., Tokyo, Japan

In surgical resection of brain tumor in the vicinity of the pyramidal tract, identification and preservation of the tract is extremely important to protect the motor function. Although DWI/DTI is useful to demonstrate the position and the direction of the deep white matter bundles, intraoperative imaging is essential during neurosurgical procedure which could cause brain deformation. To our knowledge, however, there are few reports on performing both gintraoperativeh DWI/DTI and subcortical electrical stimulation for identification of the pyramidal tract. In this study, we identified the pyramidal tract using neuronavigation based on intraoperative DWI in combination with subcortical electrical stimulation.

14:30 2999. MRI Sequences and Registration Approaches for Respiratory Motion Correction in XMR-Guided Cardiac Catheterisations – Method and First Clinical Application Andrew Peter King1, Redha Boubertakh1, Kawal S. Rhode1, Ying-Liang Ma1, Phani Chinchapatnam2, Gang Gao2, Tarinee Tangcharoen1, Matt Ginks1, David J. Hawkes2, Reza Razavi1, Tobias Schaeffter1 1Kings College, London, UK; 2University College, London, UK

We describe a novel technique for respiratory motion correction of roadmaps in XMR-guided cardiac catheterisations using a patient-specific motion model derived from MR imaging. Validation is performed on four volunteers and three clinical cases. We test two dynamic MR imaging sequences (low resolution 3-D and high resolution 2-D) and two different registration approaches (full affine and constrained affine) for forming the model. Accuracy in volunteers was 2-4mm and in clinical cases the 2-D accuracy of the roadmap was improved from up to 13mm to less than 4mm in all three cases.

15:00 3000. X-Ray Fused with Magnetic Resonance (XMR) Imaging for Accessing the Portal Vein David Arthur Woodrum1, Wesley D. Gilson2, 3, Robert Liddell2, R J. Lederman4, C Ozturk4, M Sonmez3, Thomas Link2, V Howland2, Dara L. Kraitchman2, Aravind Arepally2 1Mayo Clinic, Rochester, Minnesota, USA; 2Johns Hopkins University School of Medicine, Baltimore, Maryland, USA; 3Siemens Corporate Research, Baltimore, Maryland, USA; 4National Institutes of Health, Bethesda, Maryland, USA

We evaluated use of real-time X-ray imaging fused with MRI (XFM) to guide interventions targeting portal vein. This technique uses roadmaps from MRI-derived data to provide roadmaps during conventional X-ray fluoroscopy. Using an interventional MRI/X-ray suite equipped Siemens Espree MRI scanner and AXIOM Artis dFC. After placement of multimodality external fudicial markers over abdomen, 3D gradient echo images were acquired for marker visualization and contrast-enhanced imaging was performed for portal vein imaging. Animal was transferred to a calibrated fluoroscopy system, while portal vein was manually segmented from MR images. Image overlay of portal vein with real time fluoroscopy was feasible.

15:30 3001. Real-Time and Color-Flow Spiral MR Imaging of Peripheral Chronic Total Occlusion (CTO) Yoriyasu Suzuki1, William R. Overall1, Juan M. Santos1, Masahiro Terashima1, Fumiaki Ikeno1, Alan C. Yeung1, John M. Pauly1, Stephen B. Williams1, Michael V. McConnell1 1Stanford University, Stanford, USA

This study tested the feasibility of real-time spiral MRI (RT-MRI) techniques for visualizing peripheral arteries and chronic total occlusions (CTO) lesions in vivo in patients using RTHawk real-time system. Inflow enhancement resulted in high, pulsatile signal in patent portions of the vessel, while CTO regions exhibited consistently low signal. RT-color-flow-MRI showed pulsatile color signal in the patent segment and absence of color flow in the CTO. Post-intervention, RT-MRI confirmed vessel patency in both atherectomy and nitinol stent cases. This study demonstrates the capability of RT-MRI to visualize and assess peripheral CTO lesions prior to and following interventions at 1.5 T.

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14:00 3002. A Framework for 3D Visualization of Active Catheters Using Compressed Sensing Carsten Oliver Schirra1, 2, Sascha Krueger3, Steffen Weiss3, Reza Razavi1, Tobias Schaeffter1, Sebastian Kozerke2 1King's College London, London, UK; 2University and ETH Zurich, Zurich, Switzerland; 3Philips Medical Systems, Hamburg, Germany

True three-dimensional visualization of the full length of catheters has hitherto been impossible given scan time constraints. Images acquired with active interventional devices are inherently sparse therefore render Compressed Sensing ideally suited for accelerating data acquisition.We propose a framework for the visualization of active catheters in 3D employing CS to gain high undersampling factors making real-time applications feasible. Constraints are introduced taking into account prior knowledge of catheter geometry and catheter motion over time to improve and accelerate image reconstruction. The potential of the method is demonstrated using computer simulations and phantom experiments.

14:30 3003. A New System for Passive Tracking of a Prostate Biopsy Device with Automatic 3D Needle Position Estimation Andre de Oliveira1, Jaane Rauschenberg1, Dirk Beyersdorff2, Wolfhard Semmler1, Michael Bock1 1Deutsches Krebsforschungszentrum (dkfz), Heidelberg, Germany; 2Charite Campus Mitte, Berlin, Germany

A new passive marker system is proposed to localize the 3D needle tip position during MR-guided prostate biopsies. Modifications to a previously existing tracking sequence were made to allow for depth tracking of the passive marker and to visualize the estimated position of the biopsy gun in real-time. In a phantom experiment the error of needle tip position estimation was about 1.5 mm, with an update rate of 1 image/s. This passive concept provides a cost-effective and simple to implement alternative that is expected to significantly speed up and improve the precision of MR-guided prostate biopsies.

15:00 3004. Real-Time MR Imaging Controlled by Transperineal Needle Placement Device for MRI-Guided Prostate Biopsy and Brachytherapy Junichi Tokuda1, 2, Simon DiMaio1, 2, Gregory Fischer3, Csaba Csoma3, David Gobbi4, Gabor Fichtinger4, Nobuhiko Hata1, 2, Clare Tempany1, 2 1Brigham and Women's Hospital, Boston, Massachusetts, USA; 2Harvard Medical School, Boston, Massachusetts, USA; 3The Johns Hopikins University, Baltimore, Maryland, USA; 4Queen's University, Kingston, Canada

A real-time MR imaging integrated with surgical navigation software 3D Slicer and a MRI-compatible transperineal needle placement device using open-source software tools is presented. The system was designed to maintain the 2D imaging plane in parallel or perpendicular to the needle, allowing physicians to monitor needle advancement in the tissue in real-time. The latency and positional accuracy of the real-time image were evaluated by using a phantom in a 3T closed-bore scanner. The study showed that it is feasible to integrate the system using the open-source software tools, providing enough capability to guide prostate biopsy and brachytherapy.

15:30 3005. Control of Intravascular Catheters Using a 3D Array of Active Steering Coils Natalia Gudino1, 2, Jeremiah A. Heilman1, 3, Jamal J. Derakhshan1, 3, Jeffrey L. Sunshine3, Jeffrey L. Duerk1, 3, Mark A. Griswold1, 3 1Case Western Reserve University, Cleveland, USA; 2University Hospitals Case Medical Center, Cleveland , USA; 3University Hospitals Case Medical Center, Cleveland, USA

One of the challenges of endovascular procedures is directing a catheter tip into small or complicated blood vessels. The strong magnetic field of MRI systems provides a special environment that can be used to enable remote control of a catheter. In the present work we propose a 3D array of steering coils as a potential solution for remote control of catheters in an Interventional MRI setting. We also demonstrate methods for visualization of the catheter and/or surrounding areas.

14:00 3006. Catheter Steering in MRI Using Longitudinal Current Loops Michael Vi-Nguyen Truong1, Kevan Anderson2, Mihaela Pop2, Hartwig Peemoeller1, Alexander Dick3, Graham A. Wright2 1University of Waterloo, Waterloo, Canada; 2University of Toronto, Toronto, Canada; 3Sunnybrook Health Sciences Centre, Toronto, Canada

Electrical mapping and RF ablation of the heart requires precise maneuvering and steering of a catheter. We have developed a method for steering a catheter that exploits the static magnetic field of an MR scanner by looping a wire around the wall of a catheter (along the longitudinal axis) and applying a DC electric current. Lorentz forces cause a separation between the portions of the wire inside and outside of the catheter, resulting in a deflection. Deflections of ~4 cm are achievable with 50 mA of current in the transverse plane perpendicular to the magnetic field.

14:30 3007. A 3-DOF MR Compatible Limb Positioning Manipulator to Facilitate Magic Angle Experiments in Vivo Haytham Elhawary1, Zion Tsz Ho Tse1, Aleksandar Zivanovic1, Marc Rea1, Brian L. Davies1, M Paley2, G Bydder3, Ian Young1, Michael Lamperth1 1Imperial College London, London, UK; 2Sheffield University, Sheffield, UK; 3UCSD, USA

Magic angle studies provide useful clinical information about tissues such as tendon. We describe a system which can be used in an MRI system to orientate a patient¡¦s limb to map signal changes with angle. So that most of the patient¡¦s body does not have to move it uses three driven axes (using novel air motors) for positioning. Motion is constrained by the size of the machine DSV, the bore of the machine and the desire to keep imaging near the machine center using a computer-based algorithm. In vivo data from an early prototype is shown.

15:00 3008. The Development of Bone Cement for the Interventional MRI Florian Wichlas1, Christian Seebauer1, Rene Schilling1, Jens Rump1, jens Pinkernelle1, Florian Streitparth1, Ioannis Papanikolaou1, Sascha Chopra1, Ulf Teichgräber1, Hermann Joseph Bail1 1Charité Berlin, Berlin, Germany

As bone cement is widely used in musculoskeletal surgery but has no signal in the MRI, it cannot be directly visualized during intervention. In order to establish vertebroplasty and cancer surgery in the open MRI, visible cement becomes necessary. Several contrast agents were added to PMMA cement in order to create a signal in the MRI. Gd-DOTA, Gd-BOPTA, Mangafodipir and manganese were used. PMMA bone cement can be prepared in order to give a positive contrast in the MRI. This cement may improve safe intervention in the open MRI, and allow early coping of complications due to leaking.

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15:30 3009. Three-Dimensional Localization of MR-Visible Markers with Potential Applications in Position Tracking: Feasibility, Speed, and Precision Harald Busse1, Wilfried Gründer2, Nikita Garnov2, Michael Moche1, Thomas Kahn1 1Leipzig University Hospital, Leipzig, Germany; 2Leipzig University, Leipzig, Germany

The purpose was to evaluate the performance of an image feature discrimination based on 2D-Gaussian peak fitting for fast localization of MR-visible markers and to determine its reliability and spatial precision using inductively-coupled RF micro coils that were scanned over a wide range of positions/orientations. By using a 128-matrix, half-Fourier balanced SSFP sequence, acquisition and localization could be performed in <1.0 sec with submillimeter precision. Therefore, that approach provides a relatively simple, flexible, and safe way for selected applications, such as the tracking of patient motion or interventional instruments/devices, that do not require extremely fast position updates.

Thermal Therapy & HIFU Hall D Tuesday 13:30-15:30

13:30 3010. Clinical Use of Robot Assistance in MR Image-Guided Microwave Thermocoagulation Therapy of Liver Tumors Shigehiro Morikawa1, Toshiro Inubushi1, Koichiro Murakami1, Shigeyuki Naka1, Yoshimasa Kurumi1, Tohru Tani1, Hasnine A. Haque2, Junichi Tokuda3, Nobuhiko Hata3 1Shiga University of Medical Science, Ohtsu, Japan; 2GE Yokogawa Medical Systems, Hino, Japan; 3Brigham and Women's Hospital, Boston, Massachusetts, USA

We have developed a motorized robot with a virtual remote-center-of-motion (RCM) control to assist the choice of the puncture route in MR image-guided microwave thermocoagulation therapy of liver tumors. After the certification of MR compatibility, accuracy and safety, we have commenced the clinical use of this robot and the results were feasible. Our navigation software showed the treated and untreated areas of the tumor. We could set the target point in this software and directly instruct this point to the robot. The robot immediately led the surgeon to this point and the procedure completed accurately and quickly.

14:00 3011. MRI-Guided, Percutaneous Thermoablation in Liver Using Interstitial Applicator of Contact Ultrasound Under Active Temperature Control : A Feasibility Study in Vivo Eric Delabrousse1, Rares Salomir1, Alain Birer1, Christian Paquet2, Cyril Lafon1 1Inserm, Lyon, France; 2Ecole Nationale Veterinaire, Marcy l'Etoile, France

Contact ultrasound permits accurate control of the spatial pattern of heat deposition, with directive and angularly controlled beams. In this study we investigated the feasibility of percutaneous thermoablation in liver using an MR compatible device, delivering High Intensity Contact Ultrasound (HICU). Fast MR thermometry was used for therapy monitoring and active feedback on the applied power. No sonication-related RF artifacts were detected in any experiment. The standard deviation of the MR thermometry baseline was 1 C. The temperature controller converged to the target curve and further maintained the steady-state regime within a standard deviation of 2 C. MR followup and post mortem histology demonstrated that all individual sonications lead to near identical shape of the lesion (15±2 mm depth, 3cm equivalent diameter).

14:30 3012. MR-Guided Radiofrequency Ablation of Hepatocellular Carcinoma: Long-Term Clinical Effectiveness Stephan Clasen1, Andreas Boss1, Christina Schraml1, Jan Fritz1, Diethard Schmidt1, Fritz Schick1, Claus D. Claussen1, Philippe L. Pereira1 1University of Tübingen, Tübingen, Germany

MR-guided radiofrequency (RF) ablation in the treatment of hepatocellular carcinoma (HCC) was evaluated. The entire ablation procedure was performed in an interventional 0.2-Tesla open MR-system. In 20 patients 28 HCC with a mean diameter of 2.8 cm were treated. Technique effectiveness was achieved in 27/28 HCC (96.4%) evidenced by dynamic MR imaging at 1.5-Tesla four months after RF ablation. At a mean follow-up of 24.2 months (range: 6 – 52 months) 26/28 HCC (92.9%) showed a complete coagulation. In conclusion, MR-guided RF ablation is an effective therapy option in the treatment of HCC.

15:00 3013. MRI Monitoring and Mathematical Modeling to Predict Tissue Lesion Size from Laser Thermal Ablation Simi Paul1, Jeong Joon Park2, Stephen R. Yutzy, 12, Ravi Patel2, Sherif G. Nour1, 2, Fadi W. Abdul-Karim1, Gerald M. Saidel2, Jeffrey L. Duerk, 12 1University Hospitals Case Medical Center, Cleveland, Ohio, USA; 2Case Western Reserve University, Cleveland, Ohio, USA

This study demonstrates how a mathematical model together with MR imaging can predict lesion size from thermal ablation of a tumor in tissue. Rabbit paraspinal muscles, with and without implanted VX-2 tumor, were thermally ablated. Model-based computer simulations of temperature and cell death dynamics via MR phase and magnitude images were used to follow lesion size development. Final lesion size predicted by computational analysis correspond closely with histopathological analysis. Since MR imaging and simulations can be accomplished in seconds, this approach has potential for real-time prediction of the lesion boundary during laser thermal ablation in clinical application.

13:30 3014. MRTI Evaluation of SPIO Core Gold Coated Nanoshells for Thermal Therapy and as T2* Contrast Agent Andrew M. Elliott1, Anil M. Shetty1, Marites P. Melancon1, Xiaojun Ji1, Brian Taylor1, John D. Hazle Hazle1, Chun Li1, R. Jason Stafford1 1University of Texas M.D. Anderson Cancer Center, Houston, USA

Laser Induced Thermal Therapy (LITT) is used in conjunction with gold-silica nanoshells that have superpaprmagnetic iron oxide cores (SPIO). The optical properties of these nanoshells and their high absorbance in the near infra-red make them ideal for use in thermal therapy. The SPIO core alters the susceptibility and therefore the T2* value in regions where the nanoshells collect. The aim of this work is to validate and characterize the thermal response characteristics of these nanoparticles and to investigate their use as a T2* contrast agent.

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14:00 3015. Assess Tumor Acute Response to Photothermal Therapies by DCE-MRI Using Biodegradable Macromolecule Contrast Agent Yi Feng1, Eun-Kee Jeong2, Lyska Emerson2, Zheng-Rong Lu 1Unviersity of Utah, Salt Lake City, USA; 2Unviersity of Utah, USA

Biodegradable macromolecular contrast agents (BMCA) alleviate this toxicity problem of macromolecular contrast agents by in vivo degradation. (Gd-DTPA)-cystamine copolymers (GDCC at 40 KDa) was used to assess the acute response from tumor and to correlate it with residual tumor.

14:30 3016. A Fast Phase-Correction Algorithm for Improved Real-Time PRF Shift Thermometry Roger Jason Stafford1, Roger J. McNichols2, Ashok Gowda2, John D. Hazle1 1The University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA; 2BioTex, Inc., Houston, Texas, USA

A fast, simple loco-regional phase-correction algorithm for proton resonance frequency shift based magnetic resonance temperature imaging is tested in in vivo animal and human experiments to evaluate its potential to decrease the artifact in PRF thermometry due to motion, tissue swelling and drift. The technique is purely post-processing based and does not rely on specific acquisition techniques. Initial results relying on phase-correction only and no image registration show both a qualitative and quantitative increase in the quality of the PRF temperature map.

15:00 3017. Absolute MR Thermometry Using Time Domain Analysis of the Multi Gradient-Echo Modulus Signal Sara Maria Sprinkhuizen1, Chris J. Bakker1, Lambertus Wilhelmus Bartels1 1University Medical Center, Utrecht, Netherlands

The modulus signal of a multi gradient-echo (mFFE) sequence contains spectral information of the substances involved. In substances containing two components of which only one has a temperature dependent resonance frequency, e.g. in tissue containing water and fat, the frequency difference Δ f between the peaks in the spectrum of the mFFE signal thus provides a measure of the absolute temperature. To proof this principle, absolute temperature maps of ethylene glycol are computed, using time domain analysis of multi gradient-echo modulus signal. This technique yielded absolute temperature maps which were insensitive to field disturbances and field drift.

13:30 3018. Temperature Mapping with IDEAL Water-Fat Phase Differences Brian J. Soher1, Cory Wyatt1, Scott B. Reeder2, James R. MacFall1 1Duke University, Durham, North Carolina, USA; 2University of Wisconsin, Madison, Wisconsin, USA

Tissues containing both water and lipids, e.g. breast, confound standard MR phase methods for mapping temperatures. We demonstrate temperature changes in a water-fat phantom using an IDEAL acquisition. Active heating was applied in an OFF-ON-OFF pattern over 60 minutes. Water-fat phase angle changes were used to calculate temperature change. Calculated IDEAL-Temp values adjacent to the Luxtron probe showed excellent agreement. IDEAL water-fat methods which use fat as an internal frequency drift reference show great promise for improving MR thermometry in fatty tissues such as breast.

14:00 3019. A High Spatiotemporal Chemical Shift Imaging Technique for MR-Guided Thermal Therapy with Multi-Parametric Monitoring Capabilities Brian Allen Taylor1, Ken-Pin Hwang, 12, Andrew M. Elliott1, Anil Shetty1, John D. Hazle1, Roger Jason Stafford1 1The University of Texas M.D. Anderson Cancer Center, Houston, USA; 2GE Healthcare Technologies, Waukesha, USA

A chemical shift imaging (CSI) technique for magnetic resonance temperature imaging is presented with spatiotemporal resolutions comparable to complex phase difference (CPD) methods. This technique takes a novel approach to frequency estimation for temperature measurements via autoregressive moving average (ARMA) modeling to overcome limitations seen in low spectral resolution, Fourier-based frequency estimation methods. Also, additional measurements such as T1 and R2* can be simultaneously acquired with the PRF to facilitate a multi-parametric approach to temperature imaging.

14:30 3020. Feasibility of 1.5T MRI-Guided Transurethral 3-D Conformal Ultrasound Therapy of the Prostate: A Simulation Study Mathieu Burtnyk1, 2, Rajiv Chopra1, 2, Michael Bronskill1, 2 1Sunnybrook Health Sciences Centre, Toronto, Canada; 2University of Toronto, Toronto, Canada

The goal of this work is to use numerical simulations and 3D patient-specific models to investigate the feasibility of treating men with prostate cancer with a transurethral ultrasound therapy device and a feedback control algorithm based on clinically-relevant 1.5T MR thermometry temperature measurements (1 C noise stdev, 5s sampling). For all 20 patient models, the standard deviation of the treatment error remained below 1mm, while the maximum and minimum error were usually less than 5mm, demonstrating a high level of treatment accuracy. Treatment times are improved by a factor of six as compared to transrectal HIFU procedures.

15:00 3021. Spatial and Temporal Accuracy of Heating Using MRI-Guided Transurethral Ultrasound Therapy and Active MR Temperature Feedback Rajiv Chopra1, 2, Kee Tang1, Aaron Boyes1, Mathieu Burtnyk1, Laurence Klotz1, Michael Bronskill1 1Sunnybrook Health Sciences Centre, Toronto, Canada; 2University of Toronto, Toronto, Canada

MRI-guided transurethral ultrasound therapy was performed in a canine model to evaluate the accuracy (spatial and temporal) of heating using active MR temperature feedback.

13:30 3022. Subzero Temperature Mapping in a Cryosurgery Ice Ball by Using MR Signal Time Course Toru Yamamoto1, Aogu Yamaguchi2, Tadashi Shimizu3 1Hokkaido University, Sapporo, Japan; 2Hokkaido University Hospital, Sapporo, Japan; 3Hokkaido University , Sapporo, Japan

Cryosurgery is a technique for freezing and killing tumors by cooling the cryoprobe inserted subcutaneously. The frozen area appears dark in MR monitoring because the water of ice is MR-invisible. The malignant tumor becomes necrotic at freezing temperatures below E0ºC. However, it is hard to discern the necrotic area below E0ºC in the frozen area, so-called ice ball. To visualize the necrotic area, we developed a method to map subzero temperatures in a black ice ball and an agar phantom was imaged using a 0.3-T MRI every 20 s during the cooling of the cryoprobe. The temperature at ten points around the cryoprobe was monitored by using thermocouples and our method was confirmed.

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14:00 3023. Proton Resonant Frequency Shift and R2* in Frozen Ex Vivo Renal Tissue at 7T Elena Kaye1, 2, Stephen Lynch1, Christopher C. Caires1, Kim Butts Pauly1 1Stanford University, Palo Alto, USA

Image-guided cryoablation is a minimally invasive therapy for renal cancer. Temperature dependence of MR parameters of frozen tissue has already been studied on a low field interventional system. In this work proton resonance frequency shift and R2* of frozen renal tissue were studied on a 7T spectrometer. 1H frequency changed linearly with temperature (slope -0.009 ppm/ C). Following the transition to the solid phase, the behavior of the 1H frequency with temperature changed from linear to exponential. R2* increased linearly with decreasing temperature.

14:30 3024. To Characterize the Safety Window of Focused Ultrasound When Applied to Blood-Brain Barrier Disruption HaoLi Liu1, Po-Hong Hsu1, KoonKwan Ng, YauYau Wai, JiunJie Wang1 1ChangGung University, KueiShan, Taiwan

High Intensity Focused Ultrasound provided a new method for blood-brain-barrier disruption, which might facilitate the drug delivery to the brain. However, side effects such as hemorrhage prevent it from clinical applications. In this study, a safety window can be characterized by the combination of susceptibility weighted imaging and contrast enhanced T1 MRI.

15:00 3025. SuperParamagnetic Iron-Oxide in Monitoring of Focused Ultrasound Induced Blood-Brain Barrier Disruption HaoLi Liu1, Po-Hong Hsu1, Zeitsan Tsai1, KoonKwan Ng2, Chia-Rui Shen1, JiunJie Wang1 1ChangGung University, KueiShan, Taiwan; 2ChangGung Memorial Hospital, Taiwan

super paramagnetic iron oxide particle (SPIO) was used to monitor the Blood Brain Barrier disruption and separate it from the potentially induced brain hemorrhage by use of susceptibility weighted imaging. SPIO-enhanced SWI provides a T2 based approach to in vivo monitoring of the focused ultrasound induced BBB disruption. The mismatched areas implied an area without brain tissue damage.

B0 Shimming Hall D Monday 14:00-16:00

14:00 3026. Shimming Strategies for the Neck and C-Spine: a Computational Study Kevin M. Koch1, J A. Stainsby2 1GE Healthcare, Waukesha, Wisconsin, USA; 2GE Healthcare, Toronto, Canada

Anatomy-induced B0 perturbations in the neck and c-spine can degrade the quality of MR acquisitions. A computational study is presented whereby the efficacies of different room-temperature shimming schemes are evaluated in this anatomic region. Static 1st-order, static 2nd-order, dynamic 1st-order, and dynamic 2nd-order shimming strategies are evaluated on a computed B0 distribution. It is shown that slice-specific updating of only 0th and 1st-order shim terms can result in significant improvement over static shimming scenarios in the neck and c-spine region.

14:30 3027. Simulating the Effect of TMS-Pulses on the Evolution of Magnetization Andreas Bungert1, Richard W. Bowtell1 1University of Nottingham, Nottingham, UK

Transcranial magnetic stimulation (TMS) is a method for stimulating cortical regions of the brain using a pulsed magnetic field. In this study the influences of this field on the evolution of nuclear magnetization have been simulated based on the measured TMS pulse waveform and calculated spatial field variation due to the TMS coil. The results indicate that the TMS pulse has negligible effect on the longitudinal magnetization, but even in the case of a balanced biphasic TMS pulse causes strong dephasing of transverse magnetization over a large region adjacent to the coil.

15:00 3028. Effects of the TMS Coil on MR Image Quality in Combined TMS/fMRI Andreas Bungert1, Richard W. Bowtell1 1University of Nottingham, Nottingham, UK

By applying MR-based field mapping to the head and simple spherical phantoms, the passive effects of a TMS coil on the Bo- and B1-field homogeneity have been investigated at 1.5 and 3 T, for different coil orientations. In addition measurements of EPI time series have been used to measure the effects of the TMS coil on the signal to noise ratio (SNR) in fMRI experiments. The results show that the presence of the TMS coil generally has only a small effect on B1 and Bo homogeneity and global SNR.

15:30 3029. Correcting for B0 Field Drift in MR Temperature Mapping with Oil References Brian J. Soher1, Cory Wyatt1, Vadim Stakhursky1, James R. MacFall1 1Duke University, Durham, North Carolina, USA

Proton resonance frequency shift (PRFS) temperature mapping methods are confounded by changes in frequency not due to temperature changes, such as main B0 field drift. We demonstrate a method that uses oil filled references that are insensitive to temperature changes to estimate changes in B0 during hyperthermia treatments. A minimum curvature spline surface is fitted to phase change values in the oil references and a global B0 map is created. Phase changes not due to temperature change are removed from the PRFS data prior to temperature calculation. Corrections are demonstrated in both a phantom and a leg sarcoma patient.

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Artifact Reduction/Correction Hall D Monday 14:00-16:00

14:00 3030. A Continuous Nyquist Ghost Correction for EPI-Based FMRI Wietske van der Zwaag1, 2, José Marques1, 2, Tobias Kober1, 2, Rolf Gruetter1, 3 1Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland; 2University of Lausanne, Lausanne, Switzerland; 3Universities of Lausanne and Geneva, Switzerland

The traditional ghost correction approach based on acquiring reference k-space lines without phase-encode gradients was supplemented with schemes based on continually reversing read-out polarity in EPI in every other volume. Three strategies were evaluated using fMRI data acquired at 7 Tesla, all of which significantly reduced Nyquist ghost intensity by up to 62%, resulting in 13% higher maximum T-scores. It is concluded that at high B0 substantial Nyquist ghost reductions are possible by alternating the read-out gradient amplitude every other volume, allowing continuous artefact reduction.

14:30 3031. EPI Distortion Corrections at 4T: Multi-Channel Field Mapping and a Comparison with the Point-Spread Function Method Simon Robinson1, Jorge Jovicich1 1University of Trento, Trento, Italy

EPI distortions arising from local field inhomogeneities are severe at 4T (~10 mm), but may be remedied via the field mapping and point-spread function correction methods. We show how high quality phase images and field maps may be generated using multi-channel data, using the multiplicity of measures of phase to eliminate erroneous boundary pixel values. We acquired data from six subjects over a wide range of receiver bandwidth, and corrected with the fieldmap and point-spread function method. Using measures of boundary shape, both measures provide excellent correction. No residual distortion was evident in the image interior.

15:00 3032. The Use of Three Navigator Echoes in Cartesian EPI Reconstruction Reduces Nyquist Ghosting Andrew S. Nencka1, Andrew D. Hahn1, Daniel B. Rowe1 1Medical College of Wisconsin, Milwaukee, Wisconsin, USA

Reconstructed images from Cartesian echo planar imaging suffer from Nyquist ghosting because of hardware timing errors and eddy current effects shifting the odd and even k-space lines in opposite directions. Previous solutions to the ghosting problem have included acquiring a reference scan with no phase encoding blips or the omission of a phase encoding blip when the center line of k-space is acquired. We illustrate here a method for utilizing three navigator echoes to estimate the shifts and reduce the Nyquist ghost. This method is less computationally intensive than the two-navigator method and yields superior results to the reference scan methods. Like the two navigator method, this method additionally offers the ability to measure the center frequency offset and alternating line time shift with each image acquisition.

15:30 3033. Reduction of Shading Artifact with Center-Out View Order for Diffusion-Weighted PROPELLER Xiaoli Zhao1, Ajeetkumar Gaddipati1, Shaorong Chang1, Dawei Gui1 1GE Healthcare, Waukesha, USA

The non-CPMG nature of diffusion-weighted PROPELLER imaging causes signal dropout if the refocus flip angles are out of the desirable range. This is particularly true for 3T due to B1 inhomogeneity, and shading artifact will be introduced. In the present work, “center-out” view order is demonstrated to significantly reduce the shading artifact. For each blade in PROPELLER acquisition, the echo train is phase encoded in the way the early echoes are placed near the center k-space. Center-out view order also improves the overall SNR because of the reduced TE.

14:00 3034. Presence and Reduction of Off-Resonance Ghosting in Magnetization Prepared TrueFISP Jamal Jon Derakhshan1, 2, Mark A. Griswold1, 2, Jeffrey L. Sunshine2, Jeffrey L. Duerk, 12 1Case Western Reserve University, Cleveland, Ohio, USA; 2University Hospitals Case Medical Center, Cleveland, Ohio, USA

Magnetization storage during bSSFP acquisitions has opened the door to various manipulations of the steady state signal. First, we demonstrate that conventional periodic magnetization preparation during TrueFISP acquisitions using α/2 at TR/2 pulses can lead to significant ghosting (>1/2 amplitude of object) of off-resonant spins. Second, simulations and experimental results demonstrate the amplitude of the ghosts can be reduced to near the non-prepared bSSFP levels by partially randomizing the number of readouts collected between magnetization preparations. Phantom and human in-vivo images demonstrate both the ghosting in regularly prepared bSSFP acquisitions and the significant reductions afforded by the proposed randomization scheme.

14:30 3035. Slice Offset Frequency Adjustment (SOFA) for SSFP Imaging Martin John Graves1, Pauline Wong1, David John Lomas1 1University of Cambridge and Addenbrooke's Hospital, Cambridge, UK

Steady state free precession (SSFP) imaging is limited by off-resonance artifacts, particularly away from isocenter. We have developed a simple method to characterize the frequency offset as a function of position away from isocenter, using a uniform phantom. This correction is then applied to the scanner center frequency (f0) in either a multi-slice prescription or as part of a interactive imaging study. Initial evaluation in a phantom and normal volunteers shows a substantial reduction in artifacts when using this pre-determined correction.

15:00 3036. Contrast Enhanced T1W FLAIR PROPELLER MRI: Improvement in Flow-Related Phase Artifacts Compared to Conventional Cartesian Techniques Leland S. Hu1, John p. Karis1, Donglai Huo1, Zhiqiang Li2, Eric Aboussouan1, Nabeel Farhataziz1, Josef Debbins1, Roger Bird1, Jeff Ross1, James Pipe1 1Barrow Neurological Institute, Phoenix, USA; 2General Electric Corporation, Milwaukee, USA

Conventional Cartesian methods for T1W contrast-enhanced magnetic resonance imaging (CE-MRI) produce flow-related phase artifacts which both obscure and simulate true pathologic lesions. PROPELLER MRI scanning techniques substantially diminish the perceptibility of flow-related phase artifacts on T1W CE-MRI compared to conventional techniques. Further work is necessary to determine if these differences result in significant changes in accuracy of lesion detection.

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15:30 3037. Rapid Reference-Free Noise Reduction for Parallel MR Images Using a Principal Component Technique in Combination with Adaptive Dyadic Wavelet-Based Denoising Qi Duan1, 2, Anand S. Patel3, Andrew Francis Laine1, Philip M. Robson3, Charles A. McKenzie4, Daniel K. Sodickson2 1Columbia University, New York, New York, USA; 2New York University Medical Center, New York, New York, USA; 3Beth Israel Deaconess Medical Center and Harvard Medical School, USA; 4University of Western Ontario, Canada

Parallel acquisitions involve well-known tradeoffs between acceleration and signal-to-noise ratio (SNR). The principal component technique offers a rapid approach to noise reduction using information about the coil sensitivity encoding process. However, this method has in the past required an unaccelerated reference image. We have demonstrated a method based on dyadic wavelet expansion to adaptively derive the reference image from the accelerated one, thereby increasing ease of use. The new method also yielded sharper and more detailed image structures after noise reduction. Overall, the approach is a promising candidate for adaptive and rapid noise reduction in highly accelerated images.

Image Analysis - Parametric Mapping Hall D Monday 14:00-16:00

14:00 3038. A Novel Method of Combining Multi-Coil MRI Images: The Level-Weighted Wavelet Fusion Jeong Hwan Bang1, Andy Stenger, Todd Reed 1University of Hawaii, Honolulu, Hawaii, USA

Multi-coil MR images are conventionally combined using a magnitude sum. A problem with this approach is the loss of contrast due to the global lowpass filtering operation. Wavelet methods have been shown to be useful for reducing receiver sensitivity inhomogeneity in multi-coil applications, but not much work has been done to alleviate the loss of resolution. We present a novel Level-Weighted Wavelet Fusion (LWWF) scheme to address this. We show that the method is successful improving the contrast in multi-coil brain images at 3T.

14:30 3039. Hepatocyte Growth Factor Gene Delivered Intramyocardially Improves Cardiac Function and Strain on MR Imaging Marcus Carlsson1, Nael Osman2, David Saloner1, Alastair J. Martin1, Loi Do1, Maythem Saeed1 1University of California San Francisco, San Francisco, California , USA; 2Johns Hopkins University, Baltimore, Maryland, USA

In animal models and patients with AMI, left ventricular (LV) remodeling is accompanied by interstitial fibrosis in remote myocardium. Such fibrosis in remote myocardium is considered to be a major histological landmark resulting in cardiac dysfunction after AMI. Previous studies have shown that VEGF has a potent effect on angiogenesis, but no effect on fibrosis, whereas the other angiogenic growth factor bFGF stimulates fibrosis. On the other hand, hepatocyte growth factor (HGF) has dual effects, namely angiogenic and antifibrotic effects. In this study MR imaging has been used to determine the effects of intramyocardial HGF gene therapy transferred by plasmid DNA on left ventricular function and strain. Intramyocardial injection of plasmid expressing HGF improved LV global function and prevents LV remodeling associated with infarction. It also improved regional strain in both peri-infarcted and infarcted regions.

15:00 3040. Fast and Accurate Voxel-By-Voxel Perfusion Imaging Using Convolution Models Artem Mikheev1, Henry Rusinek1 1NYU School of Medicine, New York, New York, USA

Modeling of the perfusion using dynamic contrast-enhanced imaging based on convolution models is gaining increasing attention. To improve the computational speed and be able to control the convolution error due to discrete sampling we have developed and implemented the adaptive convolution algorithm. Algorithm was tested on the kidney perfusion model and MR renography acquisition. It enables fast and accurate analysis of DCE MR datasets.

15:30 3041. ADC Histogram Derived RGB Color-Maps for Characterizing Low Grade Glioma Subtypes Inas S. Khayal1, 2, Tracy R. McKnight1, Wei Bian1, Soonmee Cha1, Susan M. Chang1, Sarah J. Nelson1 1University of California, San Francisco, San Francisco, California , USA

Low grade gliomas are a heterogeneous group of brain tumors with variable prognosis and response to therapy. Prior studies have reported that the Apparent Diffusion Coefficient (ADC) may aid in subtyping low-grade gliomas. The goal of this study was to use ADC histograms from patients with astrocytoma and oligodendroglioma to generate RGB color-maps showing astrocytoma-like and oligodendroglioma-like regions. Because biopsies are limited to a very small piece of tissue, this technique allows for the visualization of the biologically different regions within the whole tumor mass, which may aid in image-guided biopsies, assessment of treatment response or prognosis of clinical outcome.

14:00 3042. Visceral Fat Quantification on MRI: The Impact of Partial Volume Effect Qi Peng1, Anqi Zhou1, Yao Ding2, Roderick W. McColl2, Paul T. Weatherall2 1UT Health Science Center at San Antonio, San Antonio, Texas, USA; 2UT Southwestern Medical Center at Dallas, Dallas, Texas, USA

MR images are generally known to have lower spatial resolution than CT images. This greatly reduces the accuracy of visceral fat measurement on MRI since partial-volume fat may contribute a significant part to the total visceral fat. By employing a novel fat quantification strategy, we estimated the number of full- and partial–volume fat pixels (Nf and Np, respectively) in visceral area on 9 healthy volunteers. It is found that the average Np is more than twice the average Nf (Np/Nf=2.1), and fat volume from partial-volume fat voxels is 104.0% of that from full-volume voxels. Therefore, partial volume effect is significant on MR images with typical spatial resolution.

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14:30 3043. On Automatic Regional Analysis of Quantitative Relaxation Times Mapping in the Brain Benjamin Segun Aribisala1, Jiabao He1, Peter E. Thelwall1, Kieran G. Hollingsworth1, Andrew M. Blamire1 1Newcastle University, Newcastle upon Tyne, UK

Quantitative assessment of MR images is an important step in the analysis of many types of scan data. A significant step in many methods is registration of the individual brain to a standard space. Image registration requires smoothing and re-sampling and introduces partial volume effects, biasing analysis. Here we propose an automatic division into ROIs and we use the inverse process whereby regions of interest in standard space are registered to the individual, thereby analyzing each brain in its own real space. This approach reduces partial volume errors while taking into account variations in brain shapes and sizes.

15:00 3044. Reliability and Reproducibility of Myelin Water Fraction Analysis: A Comparison of Region of Interest and Pixel by Pixel Methods Sandra M. Meyers1, Cornelia Laule2, Irene M. Vavasour2, Shannon H. Kolind2, Burkhard Maedler3, Roger Tam2, Jimmy S. Lee2, Anthony L. Traboulsee2, David K.B. Li2, Alex L. MacKay2 1University of Alberta, Edmonton, Canada; 2University of British Columbia, Vancouver, Canada; 3Philips Medical Systems, Vancouver, Canada

We compared region of interest (ROI) and pixel-by-pixel (PBP) analysis methods for myelin water fraction (MWF) determination. 20 controls were scanned twice using multi-echo T2-relaxation. For ROI-analysis, the mean pixel intensity within an ROI was fit using NNLS. In PBP-analysis, MWF was obtained for each pixel and the mean value within an ROI was calculated. PBP-analysis was more reliable among 4 different observers and gave a higher correlation, and a 3 times lower mean square difference between scans. As the PBP-method is more reproducible and gives more options for visualization and analysis of MWF, it is recommended over the ROI-method.

15:30 3045. Feasibility of Rapid B1 Mapping with RF Prepulse Tagging Xin Chen1, Xingxian Shou1, Wayne R. Dannels2 1Case Western Reserve University, Cleveland, USA; 2Toshiba Medical Research Institute USA, Inc, Cleveland, USA

A B1 mapping technique which is fast and tolerant of patient motion is desired for measuring B1 field per subject due to the dependence of the B1 field patterns upon the sample. In this work, we propose an accurate and efficient method of 2-D B1 mapping with RF prepulse tagging. Our simulation shows that the calculated B1 profile agrees with the pre-assumed B1 profile very well. We also perform an error analysis to study the precision of our algorithm in the presence of noise.

14:00 3046. Imaging and Analysing Iron Accumulations in the Human Brain Using Magnetic Resonance Imaging Guenther Grabner1, Dietrich Haubenberger1, Eduard Auff1, Siegfried Trattnig1 1Medical University of Vienna, Vienna, Austria

This work is about analyzing (phase-shift and phase-shift-symmetry) iron accumulations in brains of patients with Parkinson's disease (PD) and healthy controls by using susceptibility-weighted imaging phase. In order to perform image based phase-shift-symmetry comparisons and prevent bias due to shape differences, a symmetric phase model was build. All data-sets were non-linearly registered to the symmetric model and 3D correlation coefficients were used to determine symmetry (in the area of the Putamen). Phase-shift symmetry is a possible marker for unilaterally PD and largely independent of absolute phase-values. Phase-shift analysis show an increasing phase-shift (in anterior- posterior direction) within the Putamen.

14:30 3047. AnalyzeNNLS: Software Designed to Simplify Multiexponential Decay Image Analysis Thorarin A. Bjarnason1, J Ross Mitchell1 1University of Calgary, Calgary, Canada

Multiecho MR studies provide unique insight into tissue microstructure. Two major hurdles prevent scientists from applying this technique in their research: creating the pulse program and developing the analysis technique. We provide a solution to the latter issue by creating an easy to use, cross-platform software package, called AnalyzeNNLS, capable of analyzing multiexponential decays. This software allows scientists to perform region of interest analysis on multiecho, multislice data, thus allowing them to focus on the sciences of MRI and biology.

15:00 3048. Accurate Estimation of T1 from SPGR Signals Lin-Ching Chang1, 2, Cheng Guan Koay2, Peter J. Basser2, Carlo Pierpaoli2 1The Catholic University of America, Washington, District Of Columbia, USA; 2NICHD, National Institutes of Health, Bethesda, USA

T1 can be estimated from two or more SPGR images acquired with different flip angles and/or repetition times. However, T1 estimated by a widely-used linear method is biased due to improper accounting for noise in the fitting. This bias can be significant for clinical SPGR images, for example, T1 estimated in brain tissue (800~1600ms) can be over-estimated by 10-20%. We propose a weighting scheme that correctly accounts for the noise contribution in the fitting procedure. Simulations of SPGR experiments are used to evaluate the accuracy of the estimated T1 from the widely-used linear, the proposed weighted-uncertainty linear, and the nonlinear methods.

15:30 3049. Quantitative Estimation of Prostate Cancer Using Inner Product of Intervoxel Eigenvector (IPIE) Method Koji Ishihara1, Mikio Suga1, 2, Riwa Kishimoto2, Susumu Kandatsu2, Hiroshi Tsuji2, Hiroo Ikehira2, Takayuki Obata2 1Chiba University, Chiba, Japan; 2National Institute of Radiological Sciences, Chiba, Japan

The apparent diffusion coefficient (ADC) provides the possibility of adding information for an accurate diagnosis of prostate cancer. The ADC use only eigenvalues from the DTI information. Itfs suspected that the structure will show deformities if prostate cancer exists. Eigenvectors of the DTI might be applicable to estimate tissue structures. We propose the quantitative evaluation method, the inner product of intervoxel eigenvector (IPIE) method, to assess structural tissue changes from eigenvectors. The IPIE values in the prostate cancer region are significantly changed before and after carbon-ion radiotherapy. These results suggest the IPIE method can quantitatively evaluate changes of tissue structure.

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14:00 3050. Tagged Helium-3 MRI Analysis for Pulmonary Kinematic Quantitation Nicholas James Tustison1, Jing Cai2, Tally A. Altes1, G. Wilson Miller2, Eduard E. de Lange2, John P. Mugler III2, James C. Gee1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA; 2University Of Virginia, Charlottesville, Virginia , USA

Tagged helium-3 is used to quantify pulmonary kinematics. Sample results including visuals illustrate the feasibility of our approach.

14:30 3051. Comparison of Kinetic Parameters Estimated with Unmeasured, Partially Measured, or Fully Measured Input Functions Arvind Balachandrasekaran1, Nathan Allen Pack1, Edward V.R DiBella1 1University of Utah, Salt Lake City, USA

In this paper,complete blind and partial blind estimation were compared for estimating the kinetic parameters.The first method (complete blind) estimates the Arterial Input Function (AIF) completely whereas the second method (partial blind) estimates only the samples around the peak becausegadolinium concentration is non-linearly proportional to the signal intensity changes near the peak.The kinetic parameters estimated from partial blind estimation had a higher correlation with the truth than those obtained from complete blind estimation.

15:00 3052. Model Based Blind Estimation of Kinetic Parameters Jacob Fluckiger1, Matthias Schabel1, E.V.R. DiBella1 1University of Utah, Salt Lake City, USA

This work introduces a novel functional form for the arterial input function consisting of two gamma variate curves and a sigmoid curve. This model is then applied in iterative blind estimation to determine perfusion kinetic parameters. The blind estimation technique used alternately estimates parameters for the input function and the tissue concentration. The kinetic parameter estimates were compared with “truth” obtained from standard deconvolution. The average kinetic parameter variance between the two methods was less than 10%, suggesting blind estimation may be confidently used in situations where a directly measured AIF is not easily obtained.

15:30 3053. Optimal Processing to Derive Static PC-MRA from Time-Resolved 3D PC-MRI Data Jelena Bock1, Oliver Wieben2, Kevin M. Johnson2, Juergen Hennig1, Michael Markl1 1University Hospital, Freiburg, Germany; 2University of Wisconsin-Madison, USA

The purpose of this study was to implement and to evaluate several algorithms for the optimal extraction of PC-MRA data from flow-sensitive 4D MRI, since PC-MRA has proven to be a useful alternative to contrast-enhanced MRA. All algorithms were implemented within an interactive pre-processing tool and could be combined with additional noise masking and static tissue-removal. Results of all algorithms were compared and evaluated based on data sets with different SNR.

14:00 3054. Improved Field Map Estimation in the Presence of Multiple Spectral Components Diego Hernando1, Peter Kellman2, Justin Haldar1, Zhi-Pei Liang1 1University of Illinois at Urbana-Champaign, Urbana, Illinois, USA; 2National Institutes of Health, Bethesda, Maryland, USA

B0 field map estimation in the presence of multiple spectral components is an important and challenging problem in MRI, e.g., for cardiac and abdominal imaging, where the B0 field may contain large variations across the image. This paper presents a novel method for regularized field map estimation, which formulates the estimation of the complete field map as a joint problem (instead of, e.g., voxel-by-voxel estimation followed by smoothing). In vivo cardiac results demonstrate good robustness of the proposed method.

14:30 3055. Fast Susceptibility Weighted Imaging: FSWI Frederik Testud1, Jürgen Hennig1, Maxim Zaitsev1 1University Hospital Freiburg, Freiburg, Germany

Susceptibility weighted imaging (SWI) show a strong contrast between gray and white matter. SWI experiments are typically performed with a gradient recalled echo sequence. The image phases are highly affected by B0 fluctuations and sometimes by phase wraps which are leading to long measurement and computation times. We propose a method to obtain phase contrast images with a standard EPI sequence. The method has the advantage of rapid data acquisition and a fast computation, and is referred to as fast SWI (FSWI).

15:00 3056. A Fast and Robust Method for Quantifying Magnetic Susceptibility of Arbitrarily Shaped Objects Using MR Jaladhar Neelavalli1, Yu-Chung Norman Cheng1, Ewart Mark Haacke1, 2 1Wayne State University, Detroit, USA; 2The Magnetic Resonance Imaging Institute for Biomedical Research, Detroit, USA

We present here a novel, fast and robust method for quantifying the magnetic susceptibility of arbitrarily shaped objects using MR.

15:30 3057. Robust and Mask Free Phase Unwrapping Technique Dedicated to B0 and T2* Phase Imaging

Cyril Poupon1, 2, Christopher Wiggins1, 2, Myriam Chaumeil1, Valdis Gudmundsdottir1, 2, Fabrice Poupon1, 2 1CEA NeuroSpin, Saclay, France; 2IFR49, Saclay, France

The phase unwrapping problem occurs in different engineering domains. It can be applied directly into clinical practice (e.g. in MR angiography), but also, it can be used to estimate and adjust various MR acquisition related parameters, or to correct for some image acquisition artifacts such as susceptibility artifacts. Existing unwrapping techniques often involves the use of masks of the brain that are not necessarily easy to obtain.We introduced a fast and robust technique for unwrapping phase that do not necessitate employment of region masks and applied the technique to the phase signal of GRE data acquired at 7T.

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Pulse Sequences Hall D Tuesday 13:30-15:30

13:30 3058. Whole Orbit Soft Tissue Deformation Acquired by Accelerated 3D CSPAMM Tagging During Eye Motion Marco Piccirelli1, 2, Andrea Kaspar Rutz1, Oliver Bergamin2, Peter Boesiger1, Roger Luechinger1 1University and ETH Zurich, Zurich, Switzerland; 2University Hospital Zurich, Switzerland

In complex orbital mechanical disorders, a better comprehension of ocular motion dynamic is needed. The deformation pattern within extraocular muscles (EOM) and orbital connective tissues has not been understood yet. In this work, an accelerated truly three-dimensional tagging acquisition method is proposed enabling the assessment of motion information with whole orbit coverage in a scantime allowing good motion reproducibility. A reduced field-of-view method was incorporated and 3D data sets were acquired sequentially with line tag preparation in each of the three spatial dimensions. Data were post-processed with 3D peak-combination HARP. Tissues within the orbit could be reliably tracked and characterized.

14:00 3059. Orthogonal TrueFISP Acquisitions Using Paired Reverse Centric Phase Encoding Jamal Jon Derakhshan1, 2, Mark A. Griswold1, 2, Jeffrey L. Sunshine2, Jeffrey L. Duerk, 12 1Case Western Reserve University, Cleveland, Ohio, USA; 2University Hospitals Case Medical Center, Cleveland, Ohio, USA

Paired reverse centric phase encoding is presented as a way to eliminate saturation banding in interleaved orthogonal TrueFISP imaging. Simulation results demonstrate significant (> 2x) reduction of orthogonal plane saturation artifacts across various base resolutions, flip angles and tissue types. Phantom imaging demonstrates the ability to eliminate both saturation and eddy current artifacts by pairing the reverse centric lines. Human in vivo abdominal scout imaging demonstrates the utility of the new acquisition strategy. Application to interventional MRI is demonstrated by presenting three orthogonal images acquired during real-time guidance of an RF electrode to the porcine adrenal gland in vivo.

14:30 3060. Artifact-Free Stimulated-Echo Acquisition Mode (STEAM) Cardiac Images with Improved Signal-To-Noise Ratio (SNR) Tamer A. Basha1, ElSayed H. Ibrahim1, Nael F. Osman1 1Johns Hopkins University, Baltimore, Maryland, USA

The stimulated echo acquisition mode (STEAM) is currently used in a wide range of applications for imaging tissue parameters. However, when applying STEAM in cardiac imaging, signal loss of the myocardium has been reported due to the intravoxel dephasing of the magnetization during the contraction (or stretching) of the cardiac muscle. Despite of its intrinsically low SNR, STEAM was quite appealing for the assessment of various cardiac functions. In this work, we deal with the SNR and deformation artifactproblems in STEAM technique. First, we introduce a SSFP acquisition technique to increase the SNR then we propose a method for removing the deformation artifacts from the STEAM images.

15:00 3061. Investigation of Relationship Between Applied Current Amplitude and Measured Current Density Magnitude in a Live Pig Tim P. DeMonte1, Jia-Hong Gao2, Dinghui Wang3, Weijing Ma3, Michael L.G. Joy3 1Field Metrica Inc., Toronto, Canada; 2University of Chicago, USA; 3University of Toronto, Canada

Current density imaging is an MRI technique used to measure current density vectors in tissue. Human electro-muscular incapacitation (HEMI) devices are becoming commonly used by law enforcement and military. The ultimate goal of this work is to achieve better understanding of the effects of HEMI on physiology for enhancement of efficacy and safety. Specifically, the relationship between applied current amplitude and measured current density magnitude is investigated. This relationship is expected to be linear over small ranges, but not well understood for larger ranges. A small range is investigated in an in-vivo pig to establish a method for future work.

New Contrasts & Quantitation Hall D Tuesday 13:30-15:30

13:30 3062. Dark Blood BSSFP Imaging Using Magnetization Prepared Random Velocity Encoding Jamal Jon Derakhshan1, 2, Mark A. Griswold1, 2, Jeffrey L. Sunshine2, Jeffrey L. Duerk, 12 1Case Western Reserve University, Cleveland, Ohio, USA; 2University Hospitals Case Medical Center, Cleveland, Ohio, USA

A new method for generating steady state, short TR, dark blood bSSFP images based on magnetization prepared TrueFISP is presented. Periodically, the magnetization is returned to the z axis with an α/2 pulse. Thereafter, magnetization preparation includes randomly scaled velocity encoding, similar to RF-spoiling. Simulations demonstrate that flowing blood signal can be reduced by > 95% while stationary tissue undergoes much lower loses (~ 24%) based on T2 decay. Phantom imaging results demonstrate stationary and flowing signals consistent with predictions. Human in vivo imaging demonstrates the ability to null blood flow in a short TR magnetization prepared Cartesian bSSFP sequence.

14:00 3063. Enhanced Contrast in CEST MRI Via Intermolecular Double Quantum Coherences Shengchun Zhang1, Huijun Sun1, Zhong Chen1, Congbo Cai1, Jianhui Zhong2 1Xiamen University, Xiamen, People's Republic of China; 2University of Rochester, Rochester, New York, USA

A CEST imaging technique based on intermolecular double quantum coherence (iDQC) is proposed. Quantitative analysis and experiments in glucose agarose-gel phantoms demonstrate that, in CEST MRI, iDQC signal is more sensitive to RF saturation than the conventional SQC signal, and thus needs RF saturation pulses of lower power to achieve similar CEST image contrast. Consequently, the method can reduce the potential RF burning in clinic applications, and is expected to facilitate the study of the CEST effect in the system with exchangeable protons of low concentrations.

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14:30 3064. An Investigation of Optimizing and Translating Pulsed-Chemical Exchange Saturation Transfer (CEST) Imaging to a 3 T Clinical Scanner Phillip Zhe SUN1, Thomas Benner1, Gregory Sorensen1 1A. A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, USA

Chemical exchange saturation transfer (CEST) MRI provides a sensitive detection mechanism that allows characterization of dilute labile protons usually undetectable by MRI. Particularly, amide proton transfer (APT) imaging, a variant of CEST MRI, has been shown capable of detecting ischemic tissue acidosis, and may serve as a surrogate metabolic imaging marker. For pre-clinical CEST imaging, long continuous-wave (CW) RF irradiation is often applied so that the steady state CEST contrast can be reached. On clinical scanners, however, specific absorption rate (SAR) limit and hardware design preclude the use of CW irradiation, and instead require an irradiation scheme of repetitive RF pulses (pulsed-CEST imaging). In this work, CW- and pulsed-CEST MRI were systematically compared using a tissue-like pH phantom on an imager capable of both CW and pulsed RF irradiation schemes. The results showed that the maximally obtainable pulsed-CEST contrast is about 95% of CW-CEST contrast, and their optimal RF irradiation powers are equal. Moreover, the pulsed-CEST imaging sequence was translated to a 3 Tesla scanner and detected minor pH difference of 0.6 pH unit using exchangeable amine groups (1.9 ppm). Furthermore, pilot endogenous pulsed-APT imaging of control human volunteers was demonstrated, warranting future APT MRI of stroke patients to fully elucidate its diagnostic value.

15:00 3065. Relaxometry Changes in a Gel Dosimetry Phantom Due to Continued RF Exposure Gary Paul Liney1, Mark Godber2, Andrew D. Wilson2, John W. Goodby3 1University of Hull, Hull, UK; 2University of York, York, UK; 3University of York, York, UK

To quantify changes in transverse relaxometry, in phantoms used for MRI gel-dosimetry, due to continued RF heating in the scanner, and to map the distribution of these effects.

13:30 3066. B1 Correction for Improved Bound Pool Fraction Maps Nikola Stikov1, Robert F. Dougherty1, John Mark Pauly1 1Stanford University, Stanford, California , USA

The bound pool fraction (f) is an indicator of myelin content in the brain, and cross-relaxation imaging is an efficient method of mapping the f parameter in vivo. The first step in cross-relaxation imaging is obtaining an accurate T1 map of the brain, but B1 inhomogeneity makes this task difficult. We incorporated B1 correction in our cross-relaxation procedure, and scanned three subjects with and without this correction. Our procedure removed variations in the T1 values of white matter across subjects, while reducing the total cross-relaxation scan time.

14:00 3067. FISPCEST: A Rapid, Acquisition for Dynamic Detection of CEST/PARACEST Activity Tejas Shah1, 2, Meser Ali1, Guanshu Liu1, Mark D. Pagel1, Chris A. Flask1 1Case Western Reserve University, Cleveland, Ohio, USA

We have developed a new FISP Chemical Exchange Saturation Transfer (FISPCEST) pulse sequence to sensitively detect effects. The FISPCEST technique provides <3sec acquisition times which is an order of magnitude less than current CEST techniques. The FISPCEST acquisition combines a single, ~2sec, nonselective CEST preparation and a ~500ms FISP acquisition. The improved temporal resolution is obtained with only a 15% loss in CEST sensitivity in comparison to a spin echo CEST acquisition. The FISPCEST acquisition is adaptable to both endogenous and exogenous (PARA)CEST applications and enables the acquisition of CEST spectra maps and/or multislice CEST images in under 1 minute.

14:30 3068. Tissue-Dependent Asymmetries in the SSFP Off-Resonance Profile Karla L. Miller1, Daniel P. Bulte1, Gwenaelle Douaud1, Peter Jezzard1 1Oxford University, Oxford, UK

The SSFP signal is strongly sensitive to off-resonance, with a signal profile for an isochromat population that is theoretically symmetric about the tissue frequency ("on-resonance"). However, the existence of frequency-shifted compartments may lead to an asymmetric profile. We demonstrate this asymmetric response for tissues in the brain, finding a strongly asymmetric response in white matter, a moderately asymmetric response in gray matter and an approximately symmetric response in CSF. This response profile may be useful as a novel marker for tissue content.

15:00 3069. Dynamic Nuclear Polarization Using a Low Field Multi-Channel MR System Eugeny Krjukov1, Martyn Paley1 1University of Sheffield, Sheffield, UK

Dynamic nuclear polarisation has been investigated with the free radical carbomyl-PROXYL using a low frequency (360kHz) multi-channel MR system. Enhancement factors of up to 40 were found with 50W or ESR irradiation at 220MHz.

13:30 3070. Contrast Enhancement by Feedback-Enhanced MRI Sophia Y. Yang1, Dennis W. Hwang1, Susie Y. Huang2, Lian-Pin Hwang3, Yung-Ya Lin1 1UCLA, Los Angeles, California , USA; 2Harvard Medical School, Boston, Massachusetts, USA; 3National Taiwan University, Taipei, Taiwan

Feedback-enhanced MRI yields robust image contrast that is sensitive to small differences in the underlying microscopic frequency distributions. Important applications of this method include improving the visualization of SPIO nanoparticles through generation of positive contrast and distinguishing small changes in microscopic susceptibility corresponding to tumor and normal tissue. Using an external electronic device can significantly enhance the feedback field and open opportunities for the design of novel imaging pulse sequences in which the feedback interaction is controllable. Examples of in vitro and in vivo tumor detection in human brain tissue and mouse models of lung adenocarcinoma with active feedback will be demonstrated.

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14:00 3071. MRI Manometry Using Gas Filled Microbubbles Exhibiting High Membrane to Gas Synergy: Towards Clinical Relevance Robert Henry Morris1, Martin Bencsik1, Marie-Pierre Krafft2, Gilles Waton2, Nikolaus Nestlé3, Petrik Galvosas4, Anil Vangala, Yvonne Perrie5 1Nottingham Trent University, Nottingham, UK; 2Institut Charles Sadron, Strasbourg, France; 3BASF Aktiengesellschaft, Ludwigshafen, Germany; 4University of Leipzig, Leipzig, Germany; 5Aston University, Birmingham, UK

MRI manometry is performed in vitro using two alternative contrast agents comprised of compressible microcapsules suspended in a liquid medium presenting high viscosity with little reduction of the diffusion coefficient compared to that of bulk water. The currently available contrast agent utilising standard lipid coated gas microcapsules is shown to be highly unstable in typical clinically relevant pressure conditions, whilst perfluorinated gas microcapsules coated with a perfluoroalkylated lipid will allow in vivo measurements in the future.

14:30 3072. Visualization of Viscoelastic Properties by Combining US Pulses and MRI Ole Benjamin Oehms1, Marcus Radicke1, Sarah Wrede1, Meinert Lewerenz1, Andre Engelbertz1, Karl Maier1 1Friedrich Wilhelms Universität, Bonn, Germany

The irradiation of Ultrasound Pulses (30 ms, at 10 MHz) into a sample during a diffusion sensitive MRI sequence leads to signal changes in liquids and tissue. They are caused by the decrease of the acoustic radiation pressure due to damping of the sound wave which leads to a movement in a liquid along the path of sound propagation. This movement leads to a dephasation if it occurs while the diffusion gradient is active which results in a signal diminishment in that region. This diminishment depends on the viscoelastic properties of the sample. First measurements on Water and Glycerine and on a piece of tissue will be presented in the talk.

15:00 3073. MR Imaging of Transient Shear Waves Induced by Ultrasonic Radiation Force Remi Souchon1, Rares Salomir1, Olivier Beuf2, Denis Lyonnet3, Jean-Yves Chapelon1, Olivier Rouviere3 1INSERM U556, Lyon, France; 2CNRS UMR 5220, Lyon, France; 3Hospices Civils de Lyon, France

This study reports preliminary wave images and temperature measurements for transient MR elastography (MRE) using ultrasound radiation force. Our initial data suggest that an EPI MRE sequence is likely to provide elasticity images while ensuring patient safety.

13:30 3074. Improved MREIT Reconstruction Using Sodium MRI Mark Jason Hamamura1, L Tugan Muftuler1, Orhan Nalcioglu1 1University of California, Irvine, California , USA

In magnetic resonance electrical impedance tomography (MREIT), electrical currents are injected into an object and the resulting magnetic flux density distribution measured using MRI. These MRI measurements are then used to reconstruct the conductivity distribution within the object. In this study, we investigated the incorporation of sodium MRI data into the MREIT reconstruction algorithm. The results demonstrate that this incorporation can improve the accuracy of the reconstructed conductivity maps.

14:00 3075. SPIO Acid Dissolution Kinetics with MR Susceptometry Ludovic de Rochefort1, Yi Wang1 1Weill Medical College of Cornell University, New York, New York, USA

Superparamagnetic iron oxides benefit from a very strong magnetic moment at low field due to their superparamagnetic property. Here, we show the feasibility of monitoring chemical reaction of SPIO dissolution by acids with MRI. The magnetic moment destruction is measured continuously as a function of time with MR susceptometry.

14:30 3076. A Quantitative Approach of Extracting Magnetic Moments in Small Cylindrical Object Ching-Yi Hsieh1, Yu-Chung Norman Cheng1, Jaladhar Neelavalli1, E. Mark Haacke1 1Wayne State University, Detroit, USA

Our goal is to quantify magnetic moments of a small in-vivo object such as veins in the brain from MR images, without any a priori information. By summing up MR signals within three concentric circles, the magnetic moment of the object obtained from different complex data in the same image can be accurate within 10% of its true value. To achieve this accuracy, a long echo time may be needed. The simulations and experimental results are presented for the gel phantom. The agreement between these two results indicates a promising potential of this method.

15:00 3077. In Vivo T1ρ -Weighted MR Imaging of Rat Brain Using a Surface Coil at 11.7 Tesla Su Xu1, Jehoon Yang1, Jun Shen1 1National Institute of Mental Health, Bethesda, Maryland, USA

A sech-based adiabatic spin-lock pulse sequence to obtain T 1ρ -weighted MR images using a surface transceiver coil was optimized for enhancing tissue contrast. The utility of this technique was demonstrated using in vivo rat brains after focal bicuculline administration and an 11.7 Tesla 89 mm bore vertical microimager. Signal intensity of the lesion in the T 1ρ -weighted images was significantly elevated 50 minutes after administration of bicuculline.

13:30 3078. Magnetization-Prepared Shells for Efficient T1-Weighted Brain Imaging Yunhong Shu1, Matthew A. Bernstein1 1Mayo Clinic College of Medicine, Rochester, Minnesota, USA

To maximize the contrast in MP-RAGE brain imaging, it is desirable to select a k-space acquisition order that can sample the center of k-space compactly during the peak contrast difference between WM and GM during the inversion recovery curve. The shells trajectory is a non-Cartesian 3D trajectory with high acquisition efficiency and an inherent centric nature. It provides the flexibility required to synchronize the acquisition of the center of k-space to the contrast maximum contrast. Here we theoretically and experimentally demonstrate the feasibility of combining magnetization preparation with the shells trajectory to achieve T1-weighted brain imaging efficiently.

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14:00 3079. Flow-Independent T2-Prepared Inversion Recovery Black Blood MR Imaging Chia-Ying Liu1, 2, Oliver Wieben1, Jean H. Brittain2, Scott Brian Reeder1 1University of Wisconsin-Madison, Madison, Wisconsin, USA; 2GE Healthcare, Madison, Wisconsin, USA

Black blood prepared MRI is used extensively for cardiac and atherosclerotic plaque imaging. Most black blood sequences employ double inversion recovery, which relies on the inflow of nulled blood. As a result, double IR methods are less effective in the presence of slow flow and in-plane flow. We present a new black-black preparation scheme which employs a T2-prepared sequence in combination with an inversion recovery pulse (T2Prep-IR). Excellent blood suppression independent of flow was demonstrated in the heart and carotid arteries of volunteers.

14:30 3080. In Vivo Blood T1 Mapping Using Inversion Recovery TrueFISP Wen-Chau Wu1, Jiongjiong Wang1 1University of Pennsylvania, Philadelphia, USA

In the present study, we demonstrated the feasibility of in vivo blood T1 mapping with an inversion recovery (IR) TrueFISP sequence. The IR TrueFISP signal has been shown to vary with the flip angle, T1 and T2 of static tissue of interest. With continous inflow of flesh blood with undisturbed longitudinal magnitization, the IR TrueFISP curve of blood pool signal approximated standard T1 relaxation. The estimated blood T1 values at 3.0T match well with literature results with minimal sensitivity to variations in flip angle.

15:00 3081. Practical Optimum Experimental Designs for Fast T1 Relaxometry with SPGR Sequences Alexey Samsonov1, Andrew L. Alexander1, Youngkyoo Jung1, Aaron S. Field1 1University of Wisconsin, Madison, Wisconsin, USA

Knowledge of the longitudinal relaxation time T1 is required in many quantitative MRI applications. T1 mapping using variable flip angle SPGR acquisitions is an attractive choice due to its speed. In this work, we describe a method for automatic selection of T1 mapping flip angles, which explicitly optimizes the performance of T1 mapping for a wide range of T1 values. The method yielded 3 flip angle designs with performance similar to the previously described 10 flip angle design. This development may allow more efficient T1 mapping optimized for wide range of tissue types.

13:30 3082. Standardized Structural Magnetic Resonance Imaging in Multi-Centre Studies Using Quantitative T1 and T2 Imaging Sean CL Deoni1, Steven CR Williams2, Peter Jezzard1, John Suckling3, Declan GM Murphy2, Derek K. Jones4 1University of Oxford, Oxford, UK; 2Institute of Psychiatry, London, UK; 3University of Cambridge, Cambridge, UK; 4Cardiff University Brain Research Imaging Centre, Cardiff, UK

Multicentre studies are becoming increasingly common as they facilitate the recruitment of greater numbers of subjects while decreasing the economic cost and duration of study. However, precise matching of structural image quality, necessary to draw meaningful inferences from the data particularly in regards to morphology, becomes difficult as the number and diversity of imaging systems increases. Here we report on the use of quantitative T1 and T2 imaging for standardizing the structural imaging component of such studies, demonstrating high reproducibility of the measures across different systems.

14:00 3083. Combining Morphometry and T1 Relaxometry in a Single Imaging Protocol: Measuring T1 with MPRAGE Olivier Mougin1, Penny Gowland1 1School of Physics and Astronomy, Nottingham, UK

We are using relaxation times to study normal and pathological brain development. Acquisition times for T1 are generally long, so this study aims to make use of the anatomical image that is acquired for morphological information into the relaxometry protocol. Therefore we have optimized the Magnetization Preparation followed by a RApid Gradient Echo (MPRAGE) sequence (which is routinely used for morphology at our site) for the measurement of T1. Study on five subjects at three different fields shows agreement with the literature and gold standard sequences.

14:30 3084. Fast T1 Mapping in Human Brain Using Inversion Recovery EPI with GRAPPA at 3T and 7T John Grinstead1, William Rooney2 1Siemens Medical Solutions USA, Inc., Portland, USA; 2Oregon Health & Science University, Portland, USA

Quantitative T1 techniques find a wide range of applications in biological NMR, but the major drawback of these techniques is that they are slow. This is because the sampling requirements are high, not only must the T1 recovery be well sampled, but also spatial encoding is usually desired. This work investigates the combination of inversion recovery echo-planar and parallel imaging techniques for high-speed acquisition of quantitative T1 data sets in human brain at 3T and 7T.

15:00 3085. Measurement of R1 Dynamics Using a 3D FLASH Variable Flip Angle Sliding Window Technique Jessica Schulz1, 2, Eva Christina Wönne1, Arne Hengerer2, Wolfhard Semmler1, Michael Bock1 1Deutsches Krebsforschungszentrum (dkfz), Heidelberg, Germany; 2Siemens Medical Solutions, Erlangen, Germany

A 3D FLASH variable flip angle method was combined with a sliding window calculation to obtain the relaxation rates R1 dynamically with a temporal resolution of 10 s. In a contrast agent study on tumor-bearing mice the contrast agent-related changes in R1 could be mapped in tumors, and the R1 values were in excellent agreement with reference measurements.

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Shared Resources & Quality Control Hall D Tuesday 13:30-15:30

13:30 3086. The Neuroimaging Informatics Tools and Resources Clearinghouse (NITRC) David N. Kennedy1, Robert Buccigrossi2, Jeff Grethe, Christian Haselgrove, Nina Preuss, Keith Wagner, Mark Ellisman 1MGH, Charlestown, Massachusetts, USA; 2Turner Consulting Group, USA

NITRC, a new neuroimaging knowledge environment, is now online (www.nitrc.org). We encourage the fMRI community to try it out and provide feedback on its design, tools, resources, and content. NITRC is a knowledge environment for the fMRI community where tools and resources are presented in a coherent and synergistic environment for the advancement of MRI-based neuroscience research.

14:00 3087. PAQAP: A Quality Assessment Protocol for MRI Pieter Vandemaele1, Rik Achten1, Yves De Deene1 1Ghent University Hospital, Ghent, Belgium

Quality assessment in MR imaging provides clinician and researchers with objective measures of the performance of their MR scanner and scan protocols. PAQAP (Pieter’s Automated Quality Assurance Protocol) is a combination of a standard QA phantom and an elaborate software program for full automatic data analysis and report generation. PAQAP provides an easy way to acquire and process QA data on a regular basis with minimal interaction and within a limited time frame by an MR technologist. The system will be implemented and systematically used in a QA program at the experimental MR site of the Ghent University Hospital.

14:30 3088. MR Image Quality Evaluation Using Weighted Perceptual Difference Model (Case-PDM) Jun Miao1, Wilbur C. K. Wong1, David L. Wilson1, 2 1Case Western Reserve University, Cleveland, USA; 2University Hospital of Cleveland, Cleveland, USA

The perceptual difference model (Case-PDM) is being used to quantify image quality of fast, parallel MR acquisitions and reconstruction algorithms by comparing to slower, full k-space, high quality reference images. In this paper, we create an alternative metric weighted to image features to improve the linear correlation coefficient between human ratings and weighted Case-PDM, across a large set of MR reconstruction test images of varying quality. Our method is robust across subjects and anatomy; that is, scores maintain a high correlation with human ratings even if the test dataset is different from the training dataset.

15:00 3089. A Novel SNR Estimation Technique Applicable to Clinical Parallel MR Images: Triple Band-Width Single Acquisition Method (TriSAM) Yoshio Machida1, Hiroshi Kusahara1, Yoshimori Kassai1 1Toshiba Medical Systems Corporation, Otawara, Japan

We have developed a new technique gTriple band-width Single Acquisition Methodh (TriSAM) in which noise maps can be obtained with originally intended target images with no extra scan time. Application of this technique with parallel imaging to the head images on a volunteer provides the misregistration free noise images. The TriSAM is considered to be one of the most practical SNR estimation approaches for clinical images.

B1 Mapping Hall D Tuesday 13:30-15:30

13:30 3090. Optimal Spoiling of the Transverse Magnetization in the Actual Flip-Angle Imaging (AFI) Sequence for Fast B1 Field Mapping Vasily L. Yarnykh1 1University of Washington, Seattle, Washington, USA

A recently developed Actual Flip-angle Imaging (AFI) method allows fast B1 mapping based on the spoiled steady-state principle. This study presents theoretical and experimental examination of conditions required for optimal spoiling in the AFI sequence. It was found that the spoiling behavior of the AFI sequence is different from a traditional spoiled gradient echo sequence. To achieve optimal spoiling, appropriate combinations of an RF phase increment and spoiler gradient areas need to be used. The sequence design providing highly accurate B1 measurements and possible sources of errors are described.

14:00 3091. In-Vivo Assessment of a STEAM Sequence for B1-Mapping Rudolf Stollberger1, Thomas Birngruber2 1Graz University of Technology, Graz, Austria; 2Medical University of Graz, Austria

RF field inhomogeneities are a main source for image inhomogeneities, spatial dependent SNR and CNR and systematic errors in quantification of MRI data. A STEAM sequences was evaluated in-vivo at 3T for B1-determination in quantitative studies. It could be shown that the sequence is robust and sufficiently accurate for the application in most regions. Some problems occur in the chest from motion artefacts. The acquisition time for a scanning matrix of 128*64 was 47s for TR=800ms and 78s for TR=1300.

14:30 3092. Impact of the Correction of B1 Inhomogeneities for Dynamic Contrast-Enhanced Imaging at 3 Tesla Robert Merwa1, Franz Ebner2, Rudolf Stollberger1 1Graz University of Technology, Graz, Austria; 2Medical University of Graz, Graz, Austria

This study was performed in order to evaluate the influence of the B1-inhomogenities for dynamic contrast-enhanced MRI at 3 T. The active RF-field was measured with a stimulated echo sequence whereas the actual flip angle distribution is determined. Using a reference scan and a perfusion scan particular parameters as temporal T1 relaxation time, concentrations and arterial input function can be calculated. The results obtained with the correction of the flip angles show a significant improvement compared to the results obtained without correction. All the measurements were performed on a 3 T System (Siemens Magnetom Trio a Tim System)

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15:00 3093. Rapid RF Flip Angle Imaging Daniel Kim1, Sohae Chung1, Daniel K. Sodickson1, Leon Axel1 1New York University, New York, New York, USA

The transmit radiofrequency (RF) filed (B1) uniformity plays an important role in determining the image quality in MRI, particularly at high field strengths (≥ 3T). Accurate B1 or flip angle maps are needed to compensate for B1 variations through different compensation strategies. Among the existing methods for in vivo B1 mapping, the double angle method (DAM) is most straightforward. However, its image acquisition efficiency is very low due to a need to set TR ≥ 5 T1s. The purpose of this study is to develop a rapid in vivo B1 mapping method based upon three single-shot image acquisitions.

Image Registration & Alignment Hall D Wednesday 13:30-15:30

13:30 3094. Validation of 3D Non-Rigid Whole Body MR Image Registration Xia Li1, Thomas Yankeelov, Todd Peterson, John Gore, Benoit Dawant 1Vanderbilt University, Nashville, Tennessee, USA

The automatic registration of whole body MR images, which requires non-rigid registration techniques for thearticulated structures, remains a challenge. Although we proposed a promising registration method that permits the automatic registration of MR images for both intra- and inter-subject, one weakness is found in this algorithm: bones can be deformed incorrectly because of the surrounding structures. A modified method was proposed to constrain the deformation of bony structures. However, complete validation is required. In this study, quantitative validation results show the accuracy of our algorithm.

14:00 3095. Breast MR Registration for Evaluation of Neoadjuvant Chemotherapy Response Ruparani Chittineni1, 2, Min-Ying Su1, Orhan Nalcioglu1 1University of California, Irvine, Irvine, USA

The deformable nature of breast tissue results in significant shape differences between serial studies, making it challenging to chalk out a clear trajectory of the corresponding tumor locations. These studies correspond to MR-based monitoring of chemotherapy for therapy response evaluation. In this abstract we demonstrate the use of constraint based free-form deformations for registration of serial breast MR studies. The algorithm is especially useful in patients with multi-centric or multi-focal lesions. Also, differentiating between therapy-induced inflammation and residual disease becomes amenable. Since, tumor volumes are preserved during the transformation, mis-interpretation of results can be avoided.

14:30 3096. Image Registration of Mouse Brains Containing Varying Amounts of Extra Cortical CSF Matthijs C. van Eede1, Jason P. Lerch1, John G. Sled1 1Toronto Centre for Phenogenomics, Toronto, Canada

In recent studies we encountered brains containing varying amounts of extra cortical CSF. Using our groupwise registration method for analysis of the brains, we found this resulted in incorrect alignment. That would lead to incorrect findings. We have developed a modulation strategy to deal with this extra cortical CSF, alleviating the registration problem.

15:00 3097. Non-Rigid Registration of Diffusion Weighted MRI Using Progressive Principal Component Registration (PPCR) Andrew Melbourne1, David Hawkes1, David Atkinson1 1University College London, London, UK

Artefacts as a result of patient motion & eddy current distortions often corrupt Diffusion Weighted MR images, reducing the success of subsequent analysis. Registration of images that contain different contrast from each gradient direction may produce inaccurate results. The PPCR scheme allows diffusion direction images to be registered into a common coordinate frame by combining overlapping diffusion contrast using principal components analysis. PPCR registration is compared to data registered using an affine registration of each diffusion direction to the corresponding B0 volume. The use of the PPCR method allows enhanced feature demarcation by removing geometric distortion artefacts.

13:30 3098. Restoration of Compressed or Constricted Images: A Feasibility Study for Intra- And Inter- Imaging Modality Registration Ruparani Chittineni1, SeungHoon Ha1, Werner Roeck1, Min-Ying Su1, Orhan Nalcioglu1 1University of California, Irvine, Irvine, USA

Restoring form of compressed or deformed images is of utmost significance. Automatic non-rigid registration techniques have been applied extensively to address non-linear deformations. However, it is interesting to note that such algorithms may fail or be biased towards dominant intensity regions in the images and hence have minimal local registration. We demonstrate and compare the applicability of automatic and landmark based methods for the particular case of addressing deformation in the presence of constriction or applied compression. The near future application of the developed method is for co-registration of breast images acquired using MRI (uncompressed) and scintimammography (under light compression).

14:00 3099. Registration of 3D MR Images of the Mouse Embryos Mojdeh Zamyadi1, 2, R Mark Henkelman1, 2, Shoumo Bhattacharya3, Jurgen E. Schneider3, John G. Sled1, 2 1University of Toronto, Toronto, Canada; 2Mouse Imaging Centre, Hospital for Sick Children, Toronto, Canada; 3University of Oxford, Wellcome Trust Centre for Human Genetic, Oxford, UK

We are developing an image registration technique to detect subtle anatomical shape differences between 3D MR images of mouse embryos. In order to assess feasibility, we have used non-linear registration to align a group of genetically identical embryos. We tested the assumption that embryo anatomy is highly conserved among specimens by registering six 3D embryos together. The result of the registration process is shown in form of a final average image consisting of data from the 6 individuals, and the root mean squared (RMS) displacement image which is a representation of theanatomical variation among the genetically identical embryos. These initial findings suggest that embryo anatomy is highly conserved among specimens and that image registration of 3D MRI data is a feasible approach for subsequently detecting abnormal phenotypes.

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14:30 3100. Quality Control in a Longitudinal Multi Center Alzheimer's Disease Study Eric Westman1, Andy Simmons2, Sebastian Muehlboeck3, Tony Segerdahl4, Johan Bengtsson4, Lars-Olof Wahlund1, Simon Lovestone2, Christian Spenger4 1Department of Neurobiology, Health Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden; 2MRC Centre forNeurodegeneration Research, Institute of Psychiatry King's College, London, UK; 3McConnell Brain Imaging Center, McGill University, Montreal, Canada; 4Department of Clinical Science,Intervention and Technology, Karolinska Institutet, Stockholm, Sweden

Within the InnoMed/AddNeuroMed research project funded by the European Union, sixth frame work program, data has been successfully collected for a multi site MRI study. Quality control and quality assurance are performed on routine basis at data collection centers and at the data coordination centre. The feature-set of the database system covers the entire process from image acquisition, storage, quality control to data querying for analysis. Quality control statistics show that the performance of the participating sites is very high; 97 % of all T1 images passed QC.

15:00 3101. Validation of User Independent Planning Tool for Consistent Data Acquisition in Multi-Center Trials Esben Thade Petersen1, 2, Ivan Zimine1, 3, Xavier Golay, 14, The QUASAR Reproducibility study 1National Neuroscience Institute, Singapore, Singapore; 2Aarhus University Hospital, Aarhus, Denmark; 3Philips Medical Systems, Tokyo, Japan; 4Singapore Bioimaging Consortium, Singapore, Singapore

In this work, we evaluated the accuracy of automatic slice positioning which recently has become available on standard MRI systems. The success of MRI studies often depends on the consistency of the image acquisition and is especially important in longitudinal and multi-center trials. Differences in slice angulations and positioning can easily affect the “subjective” reading by radiologists but also the quantification in DTI, perfusion or volumetric-imaging. Three automatically planned images were acquired in 170 subjects and minor rotation and translation between scans were observed after co-registration of the images, resulting in high consistency for future trials using these tools.

13:30 3102. Exploring the Relationship Between Natural Fluctuations in Electrical Measures of Brain Activity and the BOLD Response, During Visual Stimulation Karen J. Mullinger1, Gerda B. Geirsdottir1, Matthew J. Brookes1, Peter F. Liddle1, Richard W. Bowtell1 1University of Nottingham, Nottingham, UK

The correlation of preceding alpha power and driven power with the BOLD response to a visual stimulus has been investigated using simultaneous EEG/fMRI experiments at 3 T. Despite good characterisation of the BOLD and electrical responses no correlation was found between the fluctuations in the alpha power preceding the stimulus or in the driven power and the BOLD response in data from individual subjects. A positive trend was however found when comparing the fractional difference in BOLD response and preceding alpha power in trials falling in the top and bottom quartiles binned according to the preceding alpha power across subjects.

14:00 3103. Hemispherical Constrained Surface Controller for 3D Navigation Martin John Graves1, David John Lomas1 1University of Cambridge and Addenbrooke's Hospital, Cambridge, UK

Although there has been significant development of volumetric image acquisition methodologies there has been little development of methods for subsequent reformatting of data beyond standard linear tools. This work describes the development of a 3D constrained surface controller for interrogating volumetric data. The controller allows for intuitive navigation by following an ultrasound-style motion paradigm in which data reformatting is performed over a virtual hemispherical surface around the organ of interest. Constraining the motion to an anatomically consistent surface reduces the possibility of the operator becoming spatially disorientated. The controller was evaluated in comparison to conventional reformatting software.

14:30 3104. Uncertainty in Simultaneous Estimation of Blood Oxygenation Level and Volume Fraction on the Basis of Spin Dephasing in a Vascular Network Jan Sedlacik1, 2, Jürgen R. Reichenbach1 1University Clinics of the Friedrich Schiller University, Jena, Germany

Blood oxygenation level and volume fraction are essential input parameters of theoretic models of spin dephasing in a vascular network. It is possible to estimate these parameters by fitting the simulated signal to measured signal-time curves. However, if the blood oxygenation level and volume fraction are unknown, they can not be reliably estimated by simply fitting theoretical signal curves to the measured signal decay. The purpose of this work was to unravel this difficulty of a simultaneous estimation of blood oxygenation level and volume fraction.

15:00 3105. Local Feature-Preserving Selection of Kernel Size for Unwrapping of High-Resolution Phase Images Julien Milles1, Matthijs J.P. van Osch1, Louise van der Weerd1, Rob J.A. Nabuurs1, Wouter M. Teeuwisse1, Jeroen van der Grond1, Mark A. van Buchem1, Johan H.C. Reiber1 1Leiden University Medical Center, Leiden, Netherlands

The aim of this work is to investigate the use of objective criteria to determine the optimal filtering kernel size in order to perform phase unwrapping while preserving local features on high-resolution phase images by means of a k-space filtering-based algorithm. We propose two local information-based criteria that depict the trade-off involved in phase unwrapping. We study the effect of kernel size on those criteria and show that their analysis allows determining an optimal filtering kernel size that realizes the trade-off between wraps removal and local features preservation.

13:30 3106. Dual Echo Susceptibility Weighted Imaging (SWI) : Reducing the Error in Making Phase Mask Yoshiyuki Ishimori1, Masahiko Monma, Yutaka Kouno, Makito Iizuka, Seiichi Sasaki 1Ibaraki Prefectural University of Health Sciences, Ami-machi, Inashiki-gun, Japan

The high pass filter process utilizing in susceptibility weighted imaging has the possibility of insufficient removal of phase wrapping and another artifact on the phase mask. We calculated the phase difference caused in TE interval by dual echo technique and calculated the time-invariant component of the phase. We used this time-invariant phase for making a phase mask. With this technique, severe phase wrappings were removed and edge enhancement effect around the positive phase portion was reduced.

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14:00 3107. Intelligent Image Repository for MRI Brain Clinical Trials Gianlorenzo Fagiolo1, Nick Fox2, Derek L. Hill2, 3, Adam D. Waldman4, Jo V. Hajnal1 1Imperial College,, London, UK; 2UCL, London, UK; 3London Bioscience Center, London, UK; 4Charing Cross Hospital, London, UK

Longitudinal MRI in which the same subject is scanned on multiple occasions is increasingly being used for clinical trials, and for diagnosis/monitoring of patients, particularly in brain studies. Minor errors in patient information entered into hospital information systems are common and occasionally gross errors occur. The result can be that images to be compared are wrongly identified leading to information loss in clinical trials. In this work, a MRI brain clinical trials image repository with intelligent text recognition and Image-based Subject Identification was developed. The identification proved robust both to scan quality deterioration and to progressing brain atrophy.

14:30 3108. Rapid Prototyping of a 3D Grid Phantom for MR Image Guided Therapy Quality Assurance Barbara Holshouser1, David Kittle2, James M. Slater2, Robert D. Pearlstein3 1Loma Linda University Medical Center, Loma Linda, California , USA; 2Loma Linda University, Loma Linda, California , USA; 3Duke University and Medical Center, Durham, USA

We have used rapid prototyping technology to directly fabricate a 3D grid phantom from CAD drawings. The phantom was then used to measure spatial inaccuracies in 3D images acquired in a 12 channel receive only head coil in a 3T MR scanner. The ultimate purpose is to characterize MR imaging related spatial inaccuracies for image guided surgery and radiotherapy.

15:00 3109. Validation of an Automatic Method for Change Detection in Serial Scalar Images Characterizing Diffusion Properties Hervé Boisgontier1, 2, Vincent Noblet1, Fabrice Heitz1, Lucien Rumbach3, Jean-Paul Armspach2 1Laboratoire des Sciences de l'Image, de l'Informatique et de la Télédétection, UMR CNRS-ULP 7005, Illkirch, France; 2Laboratoire d'Imagerie et de Neurosciences Cognitives, UMR CNRS-ULP 7191, Strasbourg, France; 3CHU Minjoz, Besançon, France

Studies have already highlighted diffusion property alterations induced by multiple sclerosis. This paper proposes an automatic method for detecting changes between two or more scalar images characterizing diffusion properties. Validation of the proposed approach and comparison of the impact of the scalar index used (mean diffusivity, fractional anisotropy and lattice index) have been done using synthetic simulations. Results show that the performance of the method depends on the index considered. This is mainly explained by the nature of noise, which varies from one index to the other

Motion Artifact Correction Hall D Wednesday 13:30-15:30

13:30 3110. Motion Artifact Correction with MOJITO: Practical Implications Candice Anne Bookwalter1, Mark A. Griswold1, Jeffrey L. Duerk1 1Case Western Reserve University, Cleveland, Ohio, USA

It is a well known property of Fourier Transform MRI that rigid body translational motion in image space results in linear phase accumulation in k-space. This work describes practical simulations and MR experiments using Multiple Overlapping k-space Junctions for Investigating Translating Objects (MOJITO), a correction scheme based on phase differences at trajectory intersections caused by 2D object shifts. The algorithm allows both detection and correction of motion artifacts caused by 2D rigid body translational motion. Here, MOJITO is demonstrated using the continuous sampling BOWTIE trajectory.

14:00 3111. Effect of Motion-Induced Altered Coil Sensitivity on Parallel Imaging Performance Murat Aksoy1, Roland Bammer1 1Stanford University, Stanford, California , USA

Correction of involuntary patient motion related artifacts remains to be one of the most important topics in MRI. In the specific case of rigid body motion, rotation and translation changes the position of the anatomy under examination with respect to the receiver coil, which, in turn, changes the coil sensitivity “seen” by the anatomy. In this study, we investigated the effects of this change in coil sensitivity with rigid body motion. Our results show that especially at higher reduction factors and in the case of severe patient motion, coil sensitivity profiles have to be modified accordingly to reflect the correct coil sensitivity exposure in order to accomplish accurate parallel image reconstruction.

14:30 3112. SENSE Motion Correction Julian R. Maclaren1, Bing Wu1, Philip Bones1, Rick P. Millane1, Richard Watts1 1University of Canterbury, Christchurch, New Zealand

A motion-correction technique using a multiple-shot fast spin echo (FSE) sequence is presented. SENSE is used to reconstruct a complete, albeit noisy, image from data collected in each individual shot. These images are then registered and combined to produce a motion-corrected reconstruction. This technique has the advantage that a regular reconstruction can also be obtained from the same k-space data set. Hence, little is lost by applying this technique and an advantage is gained over a standard FSE acquisition in the case of patient motion.

15:00 3113. Motion Mitigation for Eye Imaging Using Cloverleaf Navigators Andre J. W. van der Kouwe1, Thomas Benner1, Ashok Kumar1, Timo van Kerkoerle1, Graham Wiggins1, Giorgio Bonmassar1 1Massachusetts General Hospital, Charlestown, Massachusetts, USA

High-resolution imaging of the human eye in-vivo is exacerbated by involuntary motion. The eye performs small saccadic movements at irregular intervals, and moves during blinking. These movements are manifest in the MR image as blurring, and smearing in the phase encoding direction. We present a suggestion for dealing with this type of motion during imaging by oversampling in k-space while simultaneously collecting embedded motion-detecting navigators at every repetition time of the running scan. We reconstruct the image off-line by averaging only those lines of k-space that are not corrupted by motion.

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13:30 3114. Requirements on the Accuracy of Navigators for Prospective Motion Correction in High Resolution MR Imaging Maxim Zaitsev1, Oliver Speck, Jürgen Hennig1 1University Hospital Freiburg, Freiburg, Germany

Prospectively navigated MR imaging is becoming increasingly popular to overcome present measurement time and/or resolution limitations in various imaging applications. Navigated imaging appears to be the only way to overcome the limitation for isotropic resolution in length high-resolution scans, in which involuntarily movements of the order of millimetres are unavoidable. Despite of the popularity of navigators, to our knowledge no data on the required navigator accuracy are available in literature. Here, formalism is developed to analyse statistically the image artefacts introduced by the prospective motion correction based on the imaged sample properties and desired resolution.

14:00 3115. The Investigation of T2 PROPLLER Motion Estimation Efficiency Shaorong Chang1, Xiaoli Zhao1, Ajeetkumar Gaddipati1 1GE Healthcare, Waukesha, Wisconsin, USA

T2 PROPELLER reconstructs clinically valuable images with little motion artifacts. However, studies show that the motion correction efficiency depends on protocol parameter settings. In this work, the efficiency of PROPELLER motion correction with respect to field of view (FOV), views per blade and k-space coverage is analyzed using invivo data. Rotation and translation estimation accuracy were studied individually, and the overall effects of motion correction were inspected. Based on this study, tight FOV, at least 24 views per blade and 1 cm-1 k-space coverage are recommended in a T2 PROPELLER scan to obtain brain images with little motion artifacts.

14:30 3116. Respiratory Motion-Compensated Radial DCE-MRI of Chest and Abdominal Lesions Wei Lin1, Junyu Guo1, Mark A. Rosen1, Hee Kwon Song1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA

Accurate assessment of lesion perfusion with dynamic contrast-enhanced MRI (DCE-MRI) in the chest and abdominal regions is difficult due to respiratory motion. In this work, we utilize the self-gating properties of radial imaging with reconstruction flexibility afforded by the golden-angle view order scheme to effectively compensate for respiratory motion. In addition, residual motion within each image is compensated with the autofocusing technique, and motion between images corrected with image correlation. Finally, the resulting data is processed to reduce streaks and enhance SNR, using either k-space weighted image contrast (KWIC) filtering or principal component analysis (PCA). In vivo results demonstrate the effectiveness of our strategy in achieving high quality images of lesions located in the lung and the liver.

15:00 3117. Image Deformation Recovery Using Overlapping Partial Samples (IDROPS): Model-Based Respiratory Artefact Correction in Free-Breathing Liver MRI Mark J. White1, David Atkinson1, Liz Charles-Edwards2, Catherine Coolens2, Maria Hawkins2, Keiko Miyazaki3, David Collins3, Martin O. Leach3, David J. Hawkes1 1UCL, London, UK; 2Royal Marsden NHS Foundation Trust, UK; 3Institute of Cancer Research, UK

Respiratory motion needs managing in most liver MRI protocols. Given deformation fields associated with each part of acquired k-space, artefacts in free-breathing liver MRI may be corrected using a general matrix reconstruction method. iDROPS builds a parameterized non-rigid breathing model from a low-resolution training series, then finds a time-series of parameter values for an imaging acquisition by comparing the parts of k-space which overlap with the training data. The resulting estimated deformation fields are accurate to 1.5mm near the diaphragm (average of 10 studies), and are demonstrated correcting real continuously-acquired free-breathing liver data.

13:30 3118. New Approach for Affine Transform Parameters Estimation for Prospective Motion Correction Using External Sensors Brice Fernandez1, 2, Maelene Lohezic1, 2, Pierre-Andre Vuissoz2, Jacques Felblinger2 1General Electric Healthcare, Buc, France; 2IADI, Inserm ERI 13, Nancy University, Nancy, France

In most clinical applications, standard external sensors (ECG and respiratory belts) are usually used for triggering. We propose a method in two steps that use external sensors to estimate the position of an organ of interest. The first step consists in the calibration of external sensors output, based on fast imaging and a parametric motion estimation algorithm. The second step is a multivariate linear regression, computed between motion parameters and external sensors. This linear relation is then used to demonstrate the accuracy of the proposed method for prospective correction.

14:00 3119. Robust Abdominal Imaging with Motion Sensitive Sequences Using Cardiac and Respiratory Double Gating Ananth J. Madhuranthakam1, Ken-Pin Hwang2, Reed F. Busse3, Jean H. Brittain3, Neil M. Rofsky4, 5, David C. Alsop4, 5 1GE Healthcare, Boston, Massachusetts, USA; 2GE Healthcare, Houston, Texas, USA; 3GE Healthcare, Madison, Wisconsin, USA; 4Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA; 5Harvard Medical School, Boston, Massachusetts, USA

Abdominal imaging with motion sensitive sequences is challenging due to signal loss and artifacts associated with cardio-respiratory motion. Breath hold acquisitions using cardiac gating tend to decrease the signal loss, however poor patient cooperation and multiple breath holds required for large volume acquisitions can make such studies inefficient. In this work, we present an algorithm to perform prospective cardiac and respiratory double gating and demonstrate artifact free images acquired during free breathing.

14:30 3120. A Real Time Optical Motion Correction System Using a Single Camera and 2D Marker Murat Aksoy1, Rexford Newbould1, Matus Straka1, Samantha Holdsworth1, Stefan Skare1, Juan Santos1, Roland Bammer1 1Stanford University, Stanford, California , USA

Correction of motion related artifacts remains one of the most important topics in MRI. In this study, we present a real-time prospective motion correction system that uses a single camera and a 2D marker to detect and correct for rigid body motion. With the camera placed inside the magnet bore and the marker mounted rigidly on patient’s head, it is possible to perform motion correction for both in-plane and through-plane motion using this system with high accuracy and stability.

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15:00 3121. Characterization and Correction of Artifacts from Dynamic Interaction Between Motion and Position Dependent Off-Resonance Patterns Kiran Kumar Pandey1, Douglas Noll1 1University of Michigan, Ann Arbor, Michigan, USA

Movement during fMRI causes false activations and image registration introduces interpolation errors. Motion reorients the air-tissue interface in the brain and causes dynamically varying off-resonance patterns. These artifacts reduce accuracy of image registration and increase variability in time-series. This study characterized position dependent off-resonance artifacts in a susceptibility phantom and investigated effectiveness of CP gridding and Iterative image reconstruction methods with several fieldmap based off-resonance correction. Dynamically updated fieldmaps most accurately characterized and compensated for position dependent off-resonance artifacts. The commonly used static fieldmap off-resonance correction method was least accurate. This trend was also observed in quality of motion correction in phantom data.

13:30 3122. Examination of Cardiac-Related Motion in the Lower Thoracic and Lumbar Spinal Cord Daphne Yau1, 2, Chase R. Figley1, Celina Nahanni1, Patrick W. Stroman1 1Queen's University, Kingston, Canada

Spinal cord motion is the dominant source of error in functional magnetic resonance imaging and diffusion tensor imaging. Correcting for spinal cord motion induced by the cardiac cycle improves the sensitivity and reliability of these modalities. However, this motion has not been fully characterized in the lower thoracic and lumbar spinal cord. In the present study, we show minimal displacement of these spinal cord regions in association with the cardiac cycle. In conjunction with previous research, these findings demonstrate a model of spinal cord motion, in which maximal cervical motion progressively diminishes to a minimal displacement in the lumbar region.

14:00 3123. High Resolution Image Co-Registration via Phase Modulation in the Reciprocal (K) Spatial Domain James A. Goodman1, Charles S. Springer, Jr2 1Oregon Health and Science University, Portland, Oregon, USA; 2Oregon Health and Science University, Portland, USA

For many applications, it is essential that images be co-registered to a higher resolution than that intrinsic to the image. This is especially important for traditionally low spatial resolution data such as functional or DCE images. Pixel interpolation in the spatial domain can introduce artifacts and are often computationally burdensome. In this study we demonstrate the simplicity and precision of inter-image translation correction via post hoc reciprocal spatial domain (k-space) phase modulation. The co-registration method described here requires no addition image acquisition, field mapping, or pulse sequence modification.

14:30 3124. Flow Compensation in Non-Balanced SSFP Francesco Santini1, Oliver Bieri1, Klaus Scheffler1 1University of Basel/University Hospital, Basel, Switzerland

Flow compensation is a critical issue in non-balanced SSFP imaging because high first-order moments are achieved in the dephasing direction. Phase accumulation leads to steady-state disruption and consequent blurring artifacts and signal loss, especially in presence of long-T2 tissues. In this work, a theoretical explanation of the artifacts is given, showing how phase fluctuations influence the amplitude and the stability of the signal, and optimized flow compensated SSFP-FID and SSFP-echo sequences are presented. Finally, In vivo application of the sequence is demonstrated.

15:00 3125. High-Resolution MR Spectroscopy in Inhomogeneous and Unstable Fields Via Intermolecular Zero-Quantum Coherences Xi Chen1, Meijin Lin1, Tao Lin1, Zhong Chen1, Jianhui Zhong2 1Xiamen University, Xiamen, People's Republic of China; 2University of Rochester, Xiamen, New York, USA

A new iZQC pulse sequence with stroboscopic acquisition is designed to achieve high-resolution magnetic resonance spectroscopy in inhomogeneous and unstable fields. Primary results suggest potential applications for suppressions of motion-caused t1 noises and inhomogeneous broadenings in in vivo studies.

13:30 3126. Improvement of Magnetic Field Homogeneity for Cardiac MRI at 3 Tesla Miriam Rabea Kubach1, Axel Bornstedt1, Michael Schär2, Gerd Ulrich Nienhaus1, Volker Rasche1 1University Ulm, Ulm, Germany; 2The Johns Hopkins University School of Medicine, Baltimore, USA

A cardiac phase resolved B0-map was used to find the optimal shim settings depending on the current motion state. An optimal cardiac phase point for the assessment of the shim coefficients providing sufficient main field homogeneity over the entire cycle was assessed. It was found, that the shim values corresponding to mid diastole achieve the best results all over the cardiac cycle.

14:00 3127. Application of the Pseudo-Polar Fourier Transform for In-Plane Rotation Correction of MR Images Irtiza Ali Gilani1, Nadim Jon Shah1, 2 1Institute of Neurosciences and Biophysics (Medicine), Research Centre Juelich, Juelich, Germany; 2Institue of Physics, University of Dortmund, Dortmund, Germany

A technique is proposed for in-plane rotational motion correction using the registration of the 2D low-resolution images, termed implicit navigators, inherent to the acquired MR images. Most MR image registration strategies use the iterative correlation approach. The correlation is usually performed in the polar Fourier domain, whereby the interpolation errors in the polar Fourier domain are problematic. In this work the registration is performed by applying the pseudo-polar Fourier transform to the low-resolution images which neither requires interpolation nor iteration. Rotational motion in EPI images obtained at 3T field strength was corrected.

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14:30 3128. Image Based Compensation of Breathing Motion Artifacts in MRI with Continuously Moving Table Acquisitions Matthias Honal1, Ute Ludwig1, Simon Bauer1, Jochen Leupold1 1University Hospital Freiburg, Freiburg, Germany

MRI with continuously moving table is an efficient method to image arbitrary large body regions within one measurement. However, breathing motion causes problems since standard techniques to avoid breathing motion artifacts such as breath holding, prospective or retrospective gating are often not applicable or very inefficient. This work introduces a method which allows the reconstruction of artifact free images from data acquired during free breathing. Snapshots of arbitrary breathing states are acquired and consistently combined using image registration techniques. Typical breathing motion induced artifacts such as ghosting, blurring and signal cancellations are thus eliminated.

15:00 3129. Physiological Motion Correction of ASL FMRI Measurement of Rhesus Monkey Xiaodong Zhang1, Tsukasa Nagaoka1, Robbie Champion1, Timothy Q. Duong1 1Emory University, Atlanta, Georgia, USA

The Arterial Spin Labeling (ASL)-based CBF quantification is significantly vulnerable to the physiological motion because of the pair-wise subtraction of the control and labeling images. In this paper, a robust approach based on the optimal reference phase map was introduced for the physiological motion correction of the ASL functional MRI measurement. The resultant CBF temporal response and CBF activation map were improved dramatically. The method was demonstrated in the non-human primate (rhesus monkey) CBF measurement under the hypercapnia (5% CO2) condition.

13:30 3130. 3D Non-Linear Model-Driven Registration for Motion Corrupted DCE-MRI Data Angela Caunce1, Giovanni A. Buonaccorsi1, Caleb Roberts1, Geoff JM Parker1 1The University of Manchester, Manchester, UK

Many dynamic contrast enhanced MRI sequences have some form of motion corruption which may jeopardise the estimation of microvascular parameters. We present a model-driven registration which uses non-linear matrix transforms to bring the time series closer into alignment. The success of the registration is illustrated using a new alignment measure and by an independent motion assessment.

14:00 3131. A Fast Flow Compensation Technique for Self-Gated Sequences Jessica Schulz1, 2, Arne Hengerer2, Wolfhard Semmler1, Michael Bock1 1Deutsches Krebsforschungszentrum (dkfz), Heidelberg, Germany; 2Siemens Medical Solutions, Erlangen, Germany

Self-gating utilizes an additional short data acquisition in the pulse sequence for cardiac motion detection. Self-gating increases the TR of a pulse sequence, especially, if additional flow compensation gradients are used. Here, we demonstrate a new flow compensation scheme for self-gating with nearly no time penalty over conventional self-gating sequences without flow compensation.

14:30 3132. Efficient Motion Artifact Reduction Technique Based on Post-Processing Sang-Young Cho1, Eung-Yeop Kim1, Dong-Hyun Kim 1 1Yonsei University, Seoul, Republic of Korea

Post-processing motion correction techniques have previously been introduced to reduce motion artifacts. These techniques, which do not need any a priori information, have been shown to reduce translational motion artifacts effectively. One of the main limitations of these techniques however is the long processing time required to find the optimal image. Here, we propose a simple method to reduce this total processing time for metric based motion correction techniques.

15:00 3133. Relevance of Cardiac-Gating in Longitudenal Diffusion Weighted MRI Studies Josef Habib1, Jaroslav Hlinka1, Stamatios Sotiropoulos1, Christopher Tench1, Dorothee Auer1, Paul Simon Morgan1 1University of Nottingham, Nottingham, UK

While the presence of artifacts in ungated DW-images and the ability of gating to remedy these have been widely reported, the evaluation of benefits for the clinically important Diffusion-Tensor parameters has received less attention. This study aims to assess the relevance of cardiac-gating in clinical DWI-applications. To this end, the effects of cardiac-gating on precision and accuracy of Fractional Anisotropy and Mean Diffusivity measurements were analyzed, and subsequently put into context with alterations in FA of MS-patients. The observed results suggest that gating produces little benefit in group-studies but should be considered when precise individual acquisitions are needed.

RF Pulse Design Hall D Thursday 13:30-15:30

13:30 3134. Time-Optimal 3D Gradient Design for RF Shimming Maryam Etezadi-Amoli1, Adam B. Kerr1, John M. Pauly1 1Stanford University, Stanford, California , USA

Spoke trajectories that play slice-selective RF subpulses along kz are known to be effective at RF shimming. In this work, we use gradient time-optimization to achieve acceleration factors of greater than 10% for such spoke trajectories. We present simulated RF shimming performance using the time-optimal gradients and assuming an eight coil parallel transmit system.

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14:00 3135. Magnitude-Constrained Spokes Design for B1+ Inhomogeneity Correction

Rolf F. Schulte1, Mika W. Vogel1, Adam B. Kerr2, Hans-Peter Fautz1, Patrick Gross1, Yudong Zhu3, Florian Wiesinger1 1GE Global Research, Munich, Germany; 2Stanford University, Stanford, California , USA; 3GE Global Research, Niskayuna, New York, USA

Transmit field (B1+) inhomogeneity is impairing image quality at higher field strengths (B0≥3T). A common approach to improve homogeneity is to excite

with a multi-channel excitation system in combination with the spokes trajectory, which is a 3D excitation sequence. A slice is excited by regular sinc-Gaussian type of pulses. The in-plane homogeneity is improved by placing a few spokes in-plane. Traditionally, the excitation was constrained in both phase and magnitude, hence requiring a considerable amount of spokes and consequently a long overall pulse duration. In this work, we introduce a design constraining only the magnitude, hence considerably improvingB1

+ homogeneity. The design is solved with a non-linear least squares optimisation, including B0 inhomogeneity and constraining the B1 amplitudes. Validation is performed on 3T with a torso-phantom.

14:30 3136. Optimal Phase-Relaxed Design of Small-Tip-Angle Parallel Transmission RF Pulses Dan Xu1, Kevin F. King1, Graeme C. McKinnon1 1General Electric Healthcare, Waukesha, Wisconsin, USA

The existing phase-relaxed parallel transmission RF pulse design relaxes the flat phase constraint in conventional small-tip-angle (STA) design by allowing a predetermined, spatially varying target phase profile to improve the quality of magnitude profile of the resulting transverse magnetization. In this work, the pulse design is reformulated as an optimization problem with a non-quadratic cost function where the phase constraint is completed removed. It is further shown that the gradient vector of the cost function can be expressed as a closed form and a nonlinear conjugate gradient algorithm can be applied to efficiently solve the optimization problem. Bloch simulation results demonstrate that the optimal phase-relaxed design can achieve significantly better magnitude profile and/or lower RF power than the conventional STA design.

15:00 3137. Ultra-Short 2D RF Pulse for Reduced Field-Of-View SSFP Imaging Jing Yuan1, Chang-Sheng Mei1, 2, Lawrence P. Panych1 1Department of Radiology, Brigham and Women's Hospital, Harvard medical School, Boston, Massachusetts, USA; 2Department of Physics, Boston College, Boston, Massachusetts, USA

Balanced SSFP is a fast imaging sequence providing high signal-to-noise ratio. 2D RF pulse could be used for further shortening the scan time for SSFP by reducing phase encoding number in reduced field-of-view (rFOV). However, the critical requirement of short TE and TR make the use of 2D RF pulse in SSFP challenging. Ultra-short 2D RF pulse is specifically designed for rFOV imaging for SSFP. Sub-pulse duration is as short as 384us for 10mm slice thickness with max slew rate of 150T/m/s. 2.5x acceleration factor has been successfully achieved on GE Signa 1.5T and 3T scanners

13:30 3138. Segmented 2D-Selective RF Excitations Based on a Weighted Blipped-Planar Trajectory Jürgen Finsterbusch1, 2 1University Medical Center Hamburg-Eppendorf, Hamburg, Germany; 2Neuroimage Nord, Hamburg-Kiel-Lübeck, Germany

2D-selective RF excitations based on a segmented blipped-planar trajectory suffer from a reduced signal amplitude due to the lower flip angles of segments covering outer k-space lines. In applications that involve averaging, like single-voxel spectroscopy, a weighted blipped-planar trajectory can be used that favours larger flip angles over averaging. While segments with high k-space intensity are averaged as usual, a larger flip angle is assigned to low intensity segments so that effectively the same signal amplitude of the segment can be achieved without averaging. This approach considerable improves the signal-to-noise ratio efficiency without degrading the excitation profile.

14:00 3139. 2D-Selective RF Excitations Based on a Half-Fourier Blipped-Planar Trajectory Jürgen Finsterbusch1, 2 1University Medical Center Hamburg-Eppendorf, Hamburg, Germany; 2Neuroimage Nord, Hamburg-Kiel-Lübeck, Germany

2D-selective RF excitations based on a blipped-planar trajectory are well-suited for applications like reduced field-of-view imaging but suffer from the fact that half of the trajectory’s duration needs to be considered in the echo time. Thus, the usage of this trajectory for applications that require a short echo time, like proton-density weighting or single-voxel spectroscopy, is hampered. By applying the half-Fourier method known from slice-selective excitations, this problem can be solved using trajectories that start in outer k-space and end in the centre because only half of a single line of the trajectory contributes to the echo time.

14:30 3140. Constant Time VERSE for RF Amplitude Reduction in Spectral-Spatial Pulses with Improved Timing Robustness Peder E. Z. Larson1, Adam B. Kerr2, John M. Pauly2, Daniel B. Vigneron1 1University of California - San Francisco, San Francisco, California , USA; 2Stanford University, Stanford, California , USA

Spectral-spatial RF pulses often must contend with limits on RF power and amplitude, particularly for highly spatially selective pulses, high-field applications, and hyperpolarized 13C. We present a new method for reducing the peak amplitude in spectral-spatial RF pulses without introducing significant gradient delay sensitivity. Our method is an adaptation of the VERSE algorithm applicable to spatial subpulses because it maintains a constant pulse duration. It also includes an additional slew rate limit that reduces the allowable rate for larger RF amplitudes, improving the pulse performance in the presence of gradient delays.

15:00 3141. High Bandwidth Low Power Spatial Saturation Pulses for 7T Douglas Arthur Charles Kelley1 1GE Healthcare, San Francisco, California , USA

An extension to the Shinnar-Le Roux algorithm is presented allowing the design of scalable quadratic phase RF pulses, achieving significantly higher bandwidths with similar peak amplitudes and pulse widths. The algorithm is applied to the design of spatial saturation pulses for 7T. The performance of the pulses is verified in a high dielectric permittivity phantom.

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13:30 3142. Selective Adiabatic Refocusing Pulse Pair for 3D RARE Ziqi Sun1, Jay L. Zweier1 1The Ohio State University, Columbus, USA

A compact selective adiabatic full passage (AFP) pulse pair, consisted of two 90 degree hyperbolic secant (HS1_R20) pulses of alternate frequency sweep (AFS) directions, was successfully applied for spin refocusing in a 3D RARE pulse sequence. In comparison to an amplitude-modulated refocusing pulse and to a single 180 degree HS1_R20 AFP refocusing pulse, the AFS-AFP pulse pair substantially improved signal sensitivity and uniformity across the 3D volume, which is attributed to the effective compensation of the nonlinear phase dispersion and off-resonance effect associated with selective AFP pulses.

14:00 3143. Selective Adiabatic Pulses for T1-Weighted Contrast Enhancement at 0.38 T Ziqi Sun1, Sergey Petryakov1, Wael Alzawahra1, Jay L. Zweier1 1The Ohio State University, Columbus, USA

T1-weighted contrast enhancement was achieved in a MnCl2 doped phantom and an isolated rat heart perfused with free radical (TAM) doped St. Thomas solution using selective adiabatic full passage (AFP) inversion and excitation pulses (HS1_R15) in a 3D inversion-recovery (IR) GRE pulse sequence. In comparison to an amplitude modulated selective inversion pulse, the selective adiabatic inversion pulse substantially increased signal sensitivity and image contrast, which is ascribed to the mutual cacellation of the nonlinear phase dispersion between the inversion AFP pulse and the excitation AFP pulse in the IR-GRE3D sequence.

14:30 3144. The Steady State Properties of Actual Flip Angle Imaging (AFI) Kay Nehrke1 1Philips Research Europe, Hamburg, Germany

The RF and gradient spoil scheme of the Actual Flip Angle Imaging (AFI) sequence has been studied. It is shown that conventional RF spoiling using a linearly increasing spoil phase shift between successive RF pulses may interfere with the formation of a proper steady state for this specific sequence. Instead, an adapted RF spoil regime is derived, which essentially preserves the quadratic increase of the spoil phase over time. In addition, the spoiler gradient arrangement is adjusted to improve the off-resonance sensitivity of the sequence. Phantom experiments show a significantly improved image quality compared to the original spoiling regime.

15:00 3145. Regularized B1+ Map Estimation with Slice Selection Effects Amanda Kay Funai1, Jeffrey A. Fessler1, William Grissom1, Douglas C. Noll1 1University of Michigan, Ann Arbor, Michigan, USA

Spatially varying contrast and signal at high fields make a B1+ map a requirement in parallel transmit excitation. The standard method for estimating the magnitude, using the double angle formula, ignores noise and neglects effects from slice selection. This new regularized method incorporates multiple coils and multiple tip angles to estimate the magnitude and phase of the field map and accounts for slice selection effects based on the achieved slice profile. Phantom and experimental results show a smoother estimate and increased accuracy with the proposed method. The phase estimate can be used to design pulse sequences in parallel excitation.

Post-Nyquist Imaging Hall D Thursday 13:30-15:30

13:30 3146. Accelerated HYPR Reconstruction Andres Carrillo1, Reed F. Busse2, Jean H. Brittain2, Oliver Wieben3, Yan Wu3, Charles A. Mistretta3, Frank R. Korosec3 1GE Healthcare, Evanston, Illinois, USA; 2GE Healthcare, Madison, Wisconsin, USA; 3University of Wisconsin, Madison, Wisconsin, USA

The use of HYPR in time resolved contrast-enhanced angiography can produce temporal resolutions up to 100 times greater than traditional unaccelerated methods. However, the increase in computational requirements and data throughput can result in long reconstruction times, hampering the use of the technique. We propose an optimized, distributed reconstruction algorithm capable of reducing reconstruction times from several hours to several minutes, enabling the clinical use of the HYPR CE-MRA.

14:00 3147. L-Map: Exploiting Spatial-Temporal Correlation of Phase in MRI Kang Wang1, Steven Kecskemeti1, Rafael O'Halloran1, Sean Fain1, Kevin Johnson1, Oliver Wieben1, Jiang Du2, Charles Mistretta1 1University of Wisconsin-Madison, Madison, Wisconsin, USA; 2University of California, San Diego, San Diego, California , USA

Several image reconstruction techniques that are aimed to exploit the spatial-temporal correlation of MR magnitude images, such as Highly Constrained backPRojection (HYPR) and HYPR with Local Reconstruction (HYPR-LR) have been developed recently. These techniques have been developed for magnitude processing and cannot be directly applied to phase sensitive datasets due to phase wrapping and potential signal cancellations in the composite image. Here we propose a novel approach, the “L-map” concept, to overcome these limitations and evaluate the algorithm in simulations.

14:30 3148. MR Spectroscopic Imaging of Short T2 Tissue Using Complex Division (CD) HYPR-LR Reconstruction Kang Wang1, Rafael O'Halloran1, Sean Fain1, Steven Kecskemeti1, Oliver Wieben1, Kevin Johnson1, Charles Mistretta1, Jiang Du2 1University of Wisconsin-Madison, Madison, Wisconsin, USA; 2University of California, San Diego, San Diego, California , USA

Highly Constrained Back-Projection (HYPR) and HYPR with Local Reconstruction (HYPR-LR) techniques have been developed to exploit the spatial-temporal correlation for time-resolved MR using magnitude data. Here we propose a complex-valued HYPR-LR method which can be applied to other MR applications where complex images are needed, such as MR spectroscopy. We demonstrate that the Complex Division HYPR-LR, combined with ultrashort echo time (UTE) technique, can provide quantitative spectroscopic information of short T2 tissues, such as cortical bone.

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15:00 3149. Image Reconstruction of Variable Density Undersampled EPI Images Annie M. Tang1, Man Cheuk Ng1, Edmund Y. Lam1 1The University of Hong Kong, Pokfulam, Hong Kong

We applied a mathematical theory, Compressive Sensing (CS), for image reconstruction to EPI images. With the use of CS, it is possible to undersample the k-space data while preserving image quality. Thus, it allows a more extend coverage of the imaged object per unit time. EPI image qualities resulted from the CS reconstruction and its feasibility of application in functional MRI are discussed. Results indicated that CS outperforms traditional time reduction techniques. The statistical mapping in a typical fMRI experiment is comparable to the fully sampled EPI data.

13:30 3150. Prediction of HYPR and HYPR LR Performance Based on Image Sparsity and Temporal Correlation Julia V. Velikina1, Yan Wu1, Charles A. Mistretta1 1University of Wisconsin - Madison, Madison, Wisconsin, USA

We derive analytical formulae for the estimation of the reconstruction error using HYPR and HYPR LR algorithms. We conclude that the performance of these algorithms for each potential clinical application can be accurately predicted based on the a priori knowledge of image sparsity and expected temporal behavior of the image time series.

14:00 3151. Compressed Sensing MRI with Random B1 Field Florian M. Sebert1, Yi Ming Zou1, Bo Liu1, Leslie Ying1 1University of Wisconsin - Milwaukee, Milwaukee, Wisconsin, USA

Considerable attention has been focused on the design of practical sampling schemes to apply compressed sensing (CS) to MR. In this abstract, we revisit the sufficient conditions for CS matrices, and show that if the coil sensitivities or the RF excitation profiles can be designed to be spatially random, then the image can be recovered from uniformly undersampled k-space data. Our finding provides an alternative to the random sampling design for reducing the acquisition time using CS. In addition, it has the advantage that the number of samples needed is less than what is needed in the random sampling scheme.

14:30 3152. Randomly Perturbed Radial Trajectories for Compressed Sensing MRI Ali Bilgin1, 2, Ted P. Trouard1, Arthur F. Gmitro1, Maria I. Altbach1 1University of Arizona, Tucson, Arizona , USA

The recently introduced Compressed Sensing (CS) theory has the potential to significantly accelerate data acquisition in MRI. Recent results in CS theory indicate that introducing randomization into regularly structured trajectories can be beneficial. We introduce randomly perturbed radial trajectories for CS MRI and illustrate their potential benefits with examples.

15:00 3153. Data Reordering for Improved Constrained Reconstruction from Undersampled K-Space Data Ganesh Adluru1, Edward VR DiBella1 1University of Utah, Salt Lake City, USA

Here we propose a new data reordering method to improve the constrained reconstruction techniques from undersampled k-space data in MRI. In the data reordering technique the undersampled data are reordered in the signal space according to an a priori determined ordering and then appropriate constraints are applied within an iterative reconstruction. The method is widely applicable to reconstructions in which the data do not perfectly match the constraints being used and it can be used in the contexts which are based on regularization techniques. The method can be used to accelerate 2D and multi-image data acquisition cases in MRI.

13:30 3154. SparseSENSE: Randomly-Sampled Parallel Imaging Using Compressed Sensing Bo Liu1, Florian M. Sebert1, Yi Ming Zou1, Leslie Ying1 1University of Wisconsin - Milwaukee, Milwaukee, Wisconsin, USA

Recent work has applied compressed sensing (CS) to reduce scanning time in conventional Fourier imaging and demonstrated impressive results. In this abstract, we investigate the structure of the sensitivity encoding matrix in parallel imaging, and apply CS to parallel imaging to achieve an even higher reduction in scanning time than what can be achieved by each individual method alone. Our experiments show that the proposed method, named SparseSENSE, can achieve a reduction factor higher than the number of channels.

14:00 3155. Homotopic L0-Minimization for Highly-Undersampled MRI Reconstruction Joshua D. Trzasko1, Armando Manduca1 1Mayo Clinic, Rochester, Minnesota, USA

Compressive Sensing and related L1-minimization techniques have recently been demonstrated to accurately and efficiently reconstruct sparse or compressible MR images even at sampling rates far below the Nyquist limit. In this work, we propose an alternative minimization framework based on homotopic approximation of the L0-recovery problem and show that accurate MRI reconstructions are possible at sampling rates even lower than are achievable using L1-based methods.

14:30 3156. Matrix Formulation and Tikhonov Regularization of HYPR Reconstruction Maximilian Haeberlin1, 2, Stefan Skare1, Rexford D. Newbould1, Klaas Paul Pruessmann2, Roland Bammer1 1Stanford University, Stanford, California , USA; 2ETH Zurich, Zurich, Switzerland

A matrix formulation for HYPR reconstruction is presented, allowing to incorporate arbitrary regularization methods in iterative variants of HYPR. It is shown that Tikhonov regularization stabilizes recently proposed CG-HYPR without compromising speed or image quality.

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15:00 3157. Redundant Spatial Harmonic Information in Zeugmatography with Linear Encoding (R-SHIZLE) Theoretically Encodes Intra-Acquisition Decay Andrew S. Nencka1, Andrew D. Hahn1, Daniel B. Rowe1 1Medical College of Wisconsin, Milwaukee, Wisconsin, USA

Redundant spatial harmonic information is acquired in MRI because of the real-valued nature of the object being imaged. The redundancy is manifested as conjugate symmetry about the k-space origin. This symmetry is broken by both magnetic field inhomogeneity, intra-acquisition T2 decay and noise. In this abstract we simulate the generated k-space signal, including a non-negligible magnetic field inhomogeneity and a spatially varying T2 profile. We then correct the magnetic field inhomogeneity and recover the original T2 profile, with minor error, based upon the broken symmetry of the simulated k-space data. This offers the potential for quantitative T2 or T2* time series instead of usual T2 or T2* weighted image time series.

Image Segmentation Hall D Thursday 13:30-15:30

13:30 3158. Spherical Harmonic Representation Based Haptic Rendering for Medical Image Perception Zhengyi Yang1, Quang Tieng1, Viktor Vegh1, Deming Wang1 1University of Queensland, Brisbane, Australia

Haptics is referred as the technologies of generating artificial sense of touch in the interaction with the objects in virtual space. The use of visual interpretation in conjunction with a haptic device can provide a higher level of perception of medical images towards diagnosis and treatment planning. Spherical harmonics were found to be a feasible representation for haptic rendering with very good feedback characteristics. Spherical harmonics are a compact representation and can be efficiently used for both graphic and haptic representations.Haptic feedback provides another channel for the information flow in medical image perception. Multimodality images can be displayed simultaneously with less confusion by using visual and haptic feedback separately, which is envisioned as a better way for image fusion interaction. Haptically guided medical image exploration can aid the user in various tasks, such as finding and measuring anatomical and pathological features or investigating the spatial relationship between them. Force feedback can improve user performance in image manipulation tasks, such as interactive landmark selection, organ delineation and image registration.

14:00 3159. Structure-Specific White Matter Analysis of Amyotrophic Lateral Sclerosis Hui Zhang1, Paul A. Yushkevich1, John H. Woo1, Sumei Wang1, Elias R. Melhem1, James C. Gee1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA

In this study, we evaluated the use of a structure-specific WM analysis (SSWMA) framework to detect the location and magnitude of FA changes in patients with ALS. The SSWMA framework allows us to focus our analysis on the corticospinal tracts. The significant FA reductions were identified, which demonstrates the efficacy of the SSWMA framework.

14:30 3160. Automatic Segmentation of Intra-Abdominal and Subcutaneous Adipose Tissue in 3D Whole Mouse MRI Petter Ranefall1, Abdel W. Bidar1, David J. Svensson1, Paul David Hockings1 1AstraZeneca, Mölndal, Sweden

We developed fully automatic segmentation of intra-abdominal (IAT) and subcutaneous (SAT) adipose tissue in mice. The novel algorithm outlines the body, extracts fat, and segments IAT and SAT of in vivo high resolution whole mouse 3D images. It uses the Narrowest Passage Transform which codes each pixel with the radius of the narrowest passage on the widest possible 3D path to the body outline, and competitive region growing such that competing classes meet at narrow passages. The new method was tested on 32 fat fed mice independent to those used for algorithm development and shows good correlation to manual segmentation.

15:00 3161. Accurate Assessment of Muscle/fat Distribution on MR Images of the Thigh Vincenzo Positano1, Tore Christiansen2, Maria Filomena Santarelli1, Amalia Gastaldelli1, Steffen Ringgaard2, Luigi Landini3 1Institute of Clinical Physiology, Pisa, Italy; 2Aarhus University Hospital, Aarhus, Denmark; 3University of Pisa, Pisa, Italy

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13:30 3162. Structure-Specific Statistical Mapping of White Matter Tracts Paul A. Yushkevich1, Hui Zhang1, Tony Simon2, James C. Gee1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA; 2M.I.N.D. Institute, University of California, Davis, California , USA

We present a novel technique for analyzing diffusion imaging data in white matter studies. Data associated with six major white matter tracts is analyzed with the help of a geometrical model that exploits the sheet-like structure of these tracts.

14:00 3163. Development of a Reliable Analysis Method for Measurements of Breast Volume and Fibroglandular Tissue Volume in MRI Ke Nie1, Siwa Chan2, Ivy Chau2, Tiffany Tseng1, Jeon-Hor Chen1, Orhan Nalcioglu1, Min-Ying Su1 1University of California, Irvine, Irvine, California , USA; 2China Medical University Hospital, Taichung 404, Taiwan

A reliable method using computer-assisted segmentation for the breast and the fibroglandular tissue on breast MRI was developed. Breast segmentation was achieved based on individual woman¡¯s body landmarks for initial estimation, then with a combination of fuzzy C-means, b-spline fitting, and dynamic searching algorithms. 12 cases were selected for reproducibility test. The inter- and intra-operator consistency was evaluated, and the correlation was found to be higher than 0.97. This method may be applied to monitor the density change over time to evaluate the benefits or risks for each individual woman when considering chemoprevention or hormonal replacement therapy.

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14:30 3164. Robust Segmentation and Classification of Heterogeneous Myocardial Infarct Zones Jay S. Detsky1, Alexander J. Dick1, Graham A. Wright1 1Sunnybrook Health Sciences Centre, Toronto, Canada

Myocardial infarcts can be comprised of heterogeneous "gray zones" that may lead to ventricular arrhythmias. Image analysis and clustering tools have been developed and applied to inversion-recovery SSFP images to segment and classify the infarct core, gray zone, healthy myocardium, and blood. Pixel-by-pixel parameter maps are derived from the images and a modification of the fuzzy C-means algorithm is then applied. This method has been shown to be more robust than the conventional methods for the delineation of infarct gray zones.

15:00 3165. Segmentation of MR Brain Images with Intensity Correction and Partial Volume Averaging Sushmita Datta1, Balasrinivasa R. Sajja1, Renjie He1, Joseph M. Dieber1, Ponnada A. Narayana1 1Medical School, University of Texas Health Science Center at Houston, Houston, USA

The classification of brain tissues is important factor to follow changes in tissue volumes. However, the intensity non-uniformity and partial volume averaging (PVA) within voxels compromise accurate volumetric measurements. An iterative segmentation procedure that explicitly considers PVA effect along with bias field correction is proposed. Significant improvement in segmentation was observed with this method.

13:30 3166. Atlas-Based Segmentation for Quantitative Analysis of Brain Structures in the Rhesus Monkey Louis Collins1, Alexandre Coimbra2, Marie Holahan2, Richard Hargreaves2, Jacquelynn Cook2, Donald S. Williams2, Stephen Frey1 1McGill University, Montreal, Canada; 2Merck Research Laboratories, West Point, Pennsylvania, USA

Animal models are often used in pre-clinical studies of potential pharmaceuticals to study physiological mechanisms or evaluate efficacy or toxicity. We have designed and implemented an automated atlas-based segmentation (ABS) procedure for the analysis of rhesus macaque brain MRI data. This study briefly describes the image processing pipeline and presents initial results from the analysis of a group of rhesus macaques. This study shows feasibility of automatic regional segmentation of brain MRI data from rhesus monkeys.

14:00 3167. Knowledge-Based Left Ventricle Segmentation and Partial Volume Calculation in Cardiac Cine MRI Hae-Yeoun Lee1, Yi Wang1 1Cornell University, New York, USA

In this study, we propose a knowledge-based left ventricle segmentation and partial volume calculation algorithm to segment short-axis cine cardiac MRI. Coil sensitivity of magnitude image is corrected. The intensity statistics of left ventricle and myocardium are estimated by edge classification. Graph searching and expansion are applied to detect the myocardium. We segment the left ventricle using a region-growing scheme and then calculated partial volume effects by a weighting function from statistics of the left ventricle and myocardium. Using 38 subjects, we measure blood volume, ejection fraction, and myocardium mass and compare with manual contour tracing.

14:30 3168. Towards a New Automated Segmentation Method for Numerous Tissues in Reference to a Whole-Body 3D Anatomical Template Chu-Fang Lin1, Christopher M. Collins2, George Kesidis1, David J. Miller1 1The Pennsylvania State University, University Park, Pennsylvania, USA; 2Penn State College of Medicine, Hershey, Pennsylvania, USA

We developed a method to identify the location of specific tissues and organs using patient-specific 3D images and with reference to a labeled 3D template of a single “reference” body. Our segmentation approach employs an active contours algorithm and a Markov random field segmentation algorithm (MRF), with optimization based on mean-field annealing (MFA). We have derived satisfactory results when the body shape in patient-specific scans is similar to the labeled template. To obtain robust tissue/organ segmentation for diverse body shapes, we are working on deriving optimal local 3D matching that accounts for changes in tissue location, orientation, and volume.

15:00 3169. SNR Performance of Automated Geodesic Active Contour Based Liver Segmentation Dattesh D. Shanbhag1, Ajay Narayanan1, Kajoli Krishnan1, Patrice Hervo2, Rakesh Mullick1 1GE Global Research, Bangalore, India; 2GE Healthcare, Buc, France

SNR performance of geodesic active contour based automated segmentation algorithm is evaluated for 3D MRI of liver. Segmentation was performed on contrast-enhanced, T1-weighted liver volumes obtained from five patients, consequently degraded to lower SNR. The automated segmented liver volumes were compared with manually segmented liver volumes and kappa statistic (κ) calculated. Degrading the SNR from original ~294 to 12 changed κ by less than 5%. The results suggest that the algorithm will perform robustly κ > 0.8) for SNR ~= 9, translating into faster scans and shorter breath hold times for obtaining 3D MRI liver data for liver volumetry.

13:30 3170. MR Travel to Scan Image Processing for Real-Time Liver Identification Sebastian Peter Michael Dries1, Daniel Bystrov1, Vladimir Pekar2, Harald S. Heese1, Peter Koken1, Jochen Keupp1, Peter Börnert1 1Philips Research Europe, Hamburg, Germany; 2Philips Research North America, Markham, Canada

A method to detect the liver region on-the-fly in continuously moving bed magnetic resonance imaging was developed and tested on 3-D image data from ten volunteer survey examinations. The proposed method is based on first detecting the superior and inferior margin of the liver and next adapting a deformable liver model to the data. While the superior margin of the liver was detected with an accuracy of less than one voxel, the detection of the inferior margin was less precise with an accuracy of 4±3 voxels. For the envisioned application of diagnostic scan geometry definition, this detection accuracy was deemed acceptable, taking into account that the shape was captured well and the volume was not underestimated.

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14:00 3171. Robust Anatomy Recognition Approach for Automated Scan Planning of Spine MRI Examinations Harald Sepp Heese1, Daniel Bystrov1, Vladimir Pekar2, Sebastian P. M Dries1, Rüdiger Grewer1, Chiel J. den Harder3, Rene Bergmans3, Arjan W. Simonetti3, Arianne M. van Muiswinkel3 1Philips Research Europe, Hamburg, Germany; 2Philips Research North America, Markham, Canada; 3Philips Medical Systems, Best, Netherlands

Robust, unattended and fast anatomy recognition is the key pre-requisite for automated MRI scan planning. With its segmental, repetitive anatomy, spine adds the difficulty of level identification to previously existing approaches. The proposed method uses a combination of filtering techniques, prior knowledge on geometric properties of adjacent intervertebral discs as well as a statistical model of the lumbosacral transition to identify and label the spine column in presence of anatomic variability due to posture or disease. Recognition rate and processing speed from an evaluation on 90 cases prove clinical feasibility of the method.

14:30 3172. Real-Time Myocardial Segmentation in MRI Qi Duan1, Andrew Francis Laine1, Vinay M. Pai2 1Columbia University, New York, New York, USA; 2SUNY Upstate Medical University, Syracuse, New York, USA

In order to quantitatively evaluate cardiac functional images, segmentation of endocardial and epicardial boundaries of the myocardium is essential. Recent advances of high speed imaging, such as Phase Train Imaging (PTI), can provide large image data sets with very high temporal resolution that can be very valuable for diagnosing and detecting systolic dyssynchrony. An automated real-time segmentation was developed. The proposed method was tested on 414 frames of PTI data. The performance of myocardial segmentation was visually and quantitatively validated. Implemented in Matlab©, current method took less than 1.2 ms per cardiac phase, allowing realization of true real-time online segmentation.

15:00 3173. Automated Liver Volume Assessment from Contrast Scans: Impact of Pathology Ajay Narayanan1, Kajoli Banerjee Krishnan1, Rakesh Mullick1, Uday Patil1, Patrice Hervo2 1GE Global Research, Bangalore, India; 2GE Healthcare, Buc, France

Liver volume assessment for transplant, pathologic and metabolic changes using MR has primarily been via semi-automated methods. We have developed an automated method based on statistically driven data adaptive geodesic active contours to extract the liver from fast 3D high resolution T1-weighted, LAVA scans. This study is aimed at evaluating the sensitivity of our method to a range of patient pathologies against expert manual segmentation. The algorithm provides consistent assessment of liver volume compared to the expert manual segmentation (k=0.88) for embedded and focused liver pathology. The relative performance tends to degrade in the presence of peripheral liver pathology.

Spectroscopy Localization, Quantitation & Methodology Hall D Monday 14:00-16:00

14:00 3174. Comparison of Two Approaches to Model the Macromolecule Spectrum for the Quantification of Short TE 1H MRS Spectra at 14.1T< Cristina Cudalbu1, Vladimir Mlynárik, Lijing Xin, Rolf Gruetter, 2 1 Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland; 2Departments of Radiology, Universities of Lausanne and Geneva, Switzerland

The aim of the present study was to assess two approaches based on using LCModel which take the macromolecule contributions into account in the quantification step of in vivo rat brain spectra at 14.1 T: 1) the spectrum of macromolecules measured in vivo; and 2) the built-in LCModel spline baseline. Even if the fitted splines reproduce the in vivo macromolecules very well, the measured macromolecular “baseline” represents an additional prior knowledge and lead to a more accurate and reliable quantification at higher field strengths, which was attributed to an effectively increased spectral resolution of the macromolecule components.

14:30 3175. Comparison of Spectral Fitting Methods for Overlapping J-Coupled Metabolite Resonances Ati Gonenc1, Varanasi Govindaraju1, Andrew A. Maudsley1 1University of Miami, Miami, Florida, USA

The results of an automated spectral analysis package capable of performing two dimensional prior-knowledge fitting of multi-TE spectra, one dimensional fitting of TE-averaged spectra, and one dimensional fitting of conventional (single-TE) PRESS spectra, are presented for single-voxel data acquired at 3T. Improved performance and accuracy has been observed for the spectral fitting using the full 2D model in comparison to the TE-averaged and conventional PRESS fit for both in vivo and in vitro data.

15:00 3176. Angular Dispersion and Average Orientation of Bulk Triglycerides: Influence on the Proton Lineshape from Extramyocellular Fat Anthony Khuu1, Jimin Ren1, James Murdoch2, Ivan Dimitrov2, Donald Woessner1, A. Dean Sherry1, Craig Malloy1, 3 1University of Texas Southwestern Medical Center, Dallas, Texas, USA; 2Philips Medical Systems, Cleveland, USA; 3VA North Texas Healthcare System, Dallas, USA

Accurate determination of intramyocellular lipid content (IMCLs) by single-voxel proton spectroscopy or chemical shift imaging is important in clinical research projects. However, there is often significant overlap with extramyocellular lipids (EMCLs) due in part to angular dispersion of the strands of extracellular fat. Simulations of proton spectra generated from known fiber orientations and dispersion, analyzed using conventional symmetric lineshapes, resulted in overestimation of IMCL content. A new fitting algorithm assuming a Gaussian distribution of EMCLs centered from 0 to 90 degrees was developed and used for analysis of spectra acquired from calf muscle of healthy humans at 7T.

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15:30 3177. A Note on the Accurate Model-Based Spectral Fitting of Proton MRS in the Frequency Domain Zhengchao Dong1, 2, Zhishun Wang1, 2, Bradley Peterson1, 2 1Columbia University, New York, New York, USA; 2New York State Psychiatric Institute, New York, New York, USA

Model based spectral fitting is widely used in quantitative in vivo MRS. However, there is a discrepancy between the discrete Fourier transform (DFT) reconstructed MR spectrum and continuous Fourier transform (CFT) deduced spectral models, which will introduce systematic errors in the spectral quantification, especially when the quantification is based on ratios of spectral peaks. Although this discrepancy can be easily eliminated, they are often overlooked in the long TE MRS spectral fitting. We show here by computer simulation and in vivo MRS data that eliminating the difference between DFT and CFT spectra allows accurate spectral fitting in the frequency domain.

14:00 3178. Interleaved Dual-Angle Measurements for the Correction of Partial Saturation in 31P MR Spectroscopy Orlando Lopez1, Damian J. Tyler2, Mark A. Cole2, Carolyn A. Carr2, Daniel J. Stuckey2, Edward Lakatta1, Kieran Clarke2, Richard G. Spencer1 1NIH / National Institute on Aging, Baltimore, Maryland, USA; 2University of Oxford, Oxford, UK

Use of short repetition times (TR), relative to metabolite T1's, is common in NMR spectroscopy of biological samples. However, accurate quantification of metabolite concentrations from spectral resonances acquired with short TR values requires proper correction for saturation effects. The goal of this work was to determine whether accurate metabolite measurements could be performed by continuous dual-angle data collection using partially saturated spectra in the setting of chemical exchange. Simulations appropriate to a hypoxic intervention experiment in the heart were performed. Results demonstrated the feasibility of using continuous dual-angle acquisition to correct for partial saturation of metabolite resonances in bioenergetic experiments.

14:30 3179. Reproducibility of 31P Cardiac Magnetic Resonance Spectroscopy at 3T Lowri E. Cochlin1, Damian J. Tyler1, Yaso Emmanuel1, 2, Lucy Hudsmith3, Cameron J. Holloway1, 2, Stefan Neubauer3, Kieran Clarke1, Matthew Robson3 1University of Oxford, Department of Physiology, Anatomy and Genetics, UK; 2Department of Cardiovascular Medicine, UK; 3University of Oxford, Department of Cardiovascular Medicine, UK

The purpose of this work was to investigate the application, reproducibility and reliability of cardiac 31P MRS at 3 Tesla, with a view to taking advantage of the increased signal available at 3T by improving spatial resolution and increasing myocardial specificity. We present a technique that routinely provides high quality spectra along with a robust analysis method which is free from potential bias through spectral information or quality. The presented technique is suitable for widespread application both across research groups and across disease models.

15:00 3180. 31P 3D K-Space Weighted MRSI with Adiabatic Excitation: 3D Absolute Quantification of Phosphorus Metabolites in Human Liver Marek Chmelik1, 2, Albrecht Ingo Schmid1, 2, Stephan Gruber2, Julia Szendroedi3, Martin Krssak2, Siegfried Trattnig2, Ewald Moser2, Michael Roden, 13 1Karl-Landsteiner Institute for Endocrinology and Metabolism, Vienna, Austria; 2Medical University of Vienna, Vienna, Austria; 3Hanusch Hospital, Vienna, Austria

A protocol for measuring absolute concentrations of hepatic phosphorus metabolites by using a 3D k-space-weighted SI sequence with B1 homogeneity insensitive adiabatic pulses was designed and tested. Compared to excitation pulses used in previous studies adiabatic pulses used here do not need exact pulse calibration. In addition k-space weighted acquisition and 3T B0 field lead to relative high spatial resolved spectra (3.65ml) in reasonable time (34 min). The processing tool allows user friendly data processing and quantifying of hundreds of spectra per patient and producing absolute metabolic maps of 31P metabolite concentration distribution in the liver.

15:30 3181. Automatic 31P MRS Quantification in the Human Brain Based on OASIS-HSVD Algorithm Xin Wang1, Jing-Huei Lee1 1University of Cincinnati, Cincinnati, USA

A new algorithm termed Optimal Adaptive Separation of Interference Signal Hankel Singular Value Decomposition (OASIS-HSVD) is proposed as an automatic time domain method to adaptively separate distorted baselines and to quantify the target peaks from interested chemical compounds of human 31P MRS data at 4 T. This algorithm was tested on both simulation and in vivo data. The simulation used the Monte Carlo method for testing the robustness and accuracy of this algorithm. In vivo data was obtained from a 3D 31P MRS from human brain. Both studies demonstrate that the OASIS-HSVD is a promising algorithm for automatic 31P MRS quantification.

14:00 3182. Lactate Imaging with Hadamard Encoded Slice Selective SelMQC-CSI Stephen Pickup1, Seung Cheol Lee1, Jerry D. Glickson1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA

We¡¯ve presented here lactate imaging of tumor. Previously published lactate editing technique, the SelMQC sequence, is a doubly frequency selective, double quantum filtering method that is highly selective for lactate and filters out lipid signals that fall in the same chemical shift range as lactate. To enable slice selection, we added Hadamard-encoding inversion pulses in front of the SelMQC sequence with slice gradients. It achieved slice selection without conflict with lactate editing capability. We applied the sequence to a subcutaneously implanted tumor bearing mouse. Multi-slice lactate maps with 1x1x2 mm3 spatial resolution were obtained from the tumor within an hour at 9.4 T.

14:30 3183. Multi-Volume GABA-Edited Spectroscopy of the Human Brain Laura Sacolick1, Douglas L. Rothman1, Robin A. de Graaf1 1Yale University, New Haven, Connecticut, USA

The acquisition of multiple, independent volumes within a single repetition time is often desirable, but is typically limited by the inability to provide adequate magnetic field homogeneity across the volumes. Here we present multi-volume GABA-edited MRS in combination with dynamic shim updating to obtain high-quality MR spectra at 4.0 T from three volumes located in the occipital cortex, corpus callosum, and baso-frontal cortex. The three volumes were segmented into gray matter, white matter and CSF, and GABA concentrations were calculated for gray and white matter to be 1.26±0.32 and 0.54±0.15. These and other metabolite concentrations were found to be within the ranges reported in the literature.

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15:00 3184. Elevated Phosphocholine as a Marker of Carcinogenesis in the Woodchuck Model of Hepatocellular Carcinoma Eilean J. McKenzie1, 2, Marco L.H. Gruwel1 1National Research Council - Institute for Biodiagnostics, Winnipeg, Canada; 2University of Manitoba, Winnipeg, Canada

Woodchucks are the only animal model of chronic viral hepatitis and underwent repeated 31P-MRS to follow tumor growth in vivo. It was discovered that phosphomonoester resonances are elevated in tumors compared to controls. Ex vivo analysis by 31P-NMR confirmed elevations to phosphocholine contribute to PME elevation in vivo.

15:30 3185. Strategies for Reliable Quantification of Intracerebral GABA by 1H-MRS Wolfgang Bogner1, Stephan Gruber1, Andreas Stadlbauer2, Marc Doelken2, Siegfried Trattnig1, Arnd Doerfler2, Hermann Stefan2, Thilo Hammen2 1MR Center of Excellence, MUW, Vienna, Austria; 2Uniklinik Erlangen-Nuremberg, Erlangen, Germany

Gamma-aminobutyric acid (GABA) is an important inhibitatory neurotransmitter in human brain with anticonvulsive character. Because of an increased interest in GABA metabolism we tested the reliability of a special single-voxel spectroscopy (SVS) editing sequence which allows non-invasive intracerebral measurements of this neurotransmitter in 9 healthy adults on a 3 Tesla Scanner (Siemens TimTrio). Intra- and inter-subject reproducibility was assessed. Reliability of GABA/Cr and GABA/H2O ratios was compared in occipital lobe. Different quantification algorithms were compared (time-domain-line fitting and integration of signals).

14:00 3186. High Resolution NMR Spectra in Inhomogeneous Fields Via Intermolecular Multiple Quantum Coherences Without Coherence Selection Gradients Zhong Chen1, Congbo Cai1, Yanqin Lin1, Shuhui Cai1, Jianhui Zhong2 1Xiamen University, Xiamen, People's Republic of China; 2University of Rochester, Rochester, New York, USA

Coherence selection gradient has been thought to be essential for high resolution NMR spectra in inhomogeneous field based on intermolecular multiple quantum coherences (iMQC). However, our experimental results show that it can be omitted if correct phase cycling is applied. This means that the measured line-width of high resolution spectral peaks is not determined by the dipolar correlation distance caused by coherence selection gradient, but only affected by the effects of diffusion and T2 relaxation. This result prompts us to reconsider the iMQC high resolution mechanism.

14:30 3187. Detection of Low Levels of Brain Galactitol in Galactosemia Using 1H 2D Double-Quantum Spectroscopy Zhiyue Jerry Wang1, 2, Fernando Scaglia1, 2, Vernon Reid Sutton1, 2, Kerri M. Lamance2, Jill V. Hunter1, 2 1Baylor College of Medicine, Houston, USA; 2Texas Children's Hospital, Houston, USA

Galactosemia is an autosomal recessive hereditary disease of galactose metabolism. Patients have elevated urine galactitol even under the dietary restriction of galactose, due to endogenous production of galactose. With conventional proton MRS a low level galactitol (below 0.5 mM) cannot be resolved from other brain metabolites. We demonstrate a two-dimensional double-quantum 1H spectroscopy technique at 3T for detecting low levels of galactitol in the brain of galactosemics under dietary restrictions. This work opens the possibility for further investigations of the role of residual brain galactitol in the well-being of galactosemia patients.

15:00 3188. An Effective Fast Acquisition Scheme to Achieve High-Resolution MRS with J-Coupling Scaling Via Intermolecular Multiple-Quantum Coherences Xi Chen1, Meijin Lin1, Jincan Chen1, Tao Lin1, Zhong Chen1 1Xiamen University, Xiamen, People's Republic of China

A series of intermolecular double-quantum filtered (iDQF) sequence with efficient solvent suppression and different scaling factors of J-coupling constants, named iDQF-HOMOGENIZED II (abbreviated as iDH2), are designed to achieve fast acquisition of high-resolution spectra in inhomogeneous fields. Experiments on swine brain tissues were performed to test the feasibility of the new method. The results suggest potential applications for in vivo spectroscopy.

15:30 3189. A Flexible IMQC Method for Accurate Determination of J-Coupling Constants in Inhomogeneous Fields Yanqin Lin1, Shuhui Cai1, Yuqing Huang1, Zhong Chen1, Jianhui Zhong2 1Xiamen University, Xiamen, People's Republic of China; 2University of Rochester, Rochester, New York, USA

An improved pulse sequence was developed to scale apparent J coupling constants by a scaling factor ranging theoretically from zero (completely decoupled) to infinity under inhomogeneous fields via intermolecular multiple-quantum coherences. Scaling up the apparent J coupling constants allows more accurate measurement of small J coupling constants, and a completely decoupled homonuclear spectrum can be of considerable help for improving signal separation and thus peak assignment in MRS. The resulting spectrum retains conventional high-resolution NMR spectral information.

Hyperpolarized 13C & Other Nuclei Hall D Monday 14:00-16:00

14:00 3190. Reduction of the Myocardial Intracellular Matrix as Measured by Hyperpolarized 13C NMR Matthew E. Merritt1, 2, Crystal Harrison2, Rajesh Pidikiti1, Charles Storey1, Shawn C. Burgess1, Craig R. Malloy1, A. Dean Sherry1, 2 1UTSW Medical Center, Dallas, Texas, USA; 2UT Dallas, Richardson, Texas, USA

Infusion of a combination of octanoate and pyruvate is shown to inhibit pyruvate dehydrogenase (PDH) flux as measured using hyperpolarized [1-13C]-pyruvate and 13C NMR in a perfused rat heart. Octanoate,a medium chain fatty acid that freely diffuses into the cell, provides extra reducing equivalents to the mitochondria, ultimately shifting the REDOX state of the heart and increasing the production of lactate as well as blocking the appearance of 13CO2 and H13CO3

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14:30 3191. Strategies to Prolong the T1 Times in Hyperpolarized 13C and 15N Biomolecules Jan-Bernd Hövener1 1HMRI, Pasadena, California , USA

The advantage of hyperpolarization, with signal enhancement approaching 100.000 fold, is limited by the intrinsic lifetime T1. Biomedical applications which can be achieved within a timeframe of 5 T1 (~100s) are limited. A major hurdle is therefore to retain the high polarization over time.Here, we describe a simple measure which significantly prolongs T1. After deuteration of 4 PASADENA molecules (13C, 15N), or by dissolution in D2O, the T1 was increased 6.5 fold max., ~two-fold in average. This widens the range for applications of long-lived, hyperpolarized biomolecules in-vivo, including oncology, vulnerable plaque, cancer biomarkers and oncogene tracking.

15:00 3192. In Vivo Hyperpolarized 13C MRS/MRSI Using 13C-Lactate as the Pre-Polarized Substrate Albert P. Chen1, John Kurhanewicz1, Robert Bok1, Duan Xu1, David Joun1, Vickie Zhang1, Sarah J. Nelson1, Ralph E. Hurd2, Daniel B. Vigneron1 1UCSF, San Francisco, California , USA; 2GE Healthcare, Menlo Park, California , USA

Prior studies have shown the ability to detect the metabolic conversion of the hyperpolarized 13C-pyruvate into 13C-lactate, 13C-alanine and 13C-bicarbonate in animal models. In this study, a hyperpolarized MR probe based on 13C1-lactate as the substrate for in vivo 13C MRS/MRSI studies was developed. After injection of hyperpolarized 13C1-lactate, metabolic products 13C1-pyruvate and 13C1-alanine were observed in normal rats and in transgenic mouse prostate cancer models. This study demonstrated the feasibility of using pre-polarized 13C1-lactate to study lactate metabolism as well as tumor lactate uptake in vivo.

15:30 3193. Establishment of Hyperpolarized 13C MR in the Isolated Perfused Heart Marie Allen Schroeder1, Lisa C. Heather1, Mark A. Cole1, Kieran Clarke1, George K. Radda1, Damian J. Tyler1 1University of Oxford, Oxford, UK

This metabolic information available from hyperpolarized 13C MR could provide the basis for kinetic modelling of cellular uptake and enzymatic activity; however, understanding of the physiological interactions between the hyperpolarized substrate and tissue is necessary. The isolated perfused heart provides the ideal model system to gain this understanding, as many parameters can be easily controlled. This study demonstrated the methodology we have developed to inject hyperpolarized 1-13C-pyruvate into the perfused heart without affecting heart function, and to monitor pyruvate uptake and metabolism. Further, we have directly compared our perfused heart spectra with analogous in vivo results.

14:00 3194. The Effect of Hyperpolarized Tracer Concentration on Myocardial Uptake and Metabolism Damian J. Tyler1, Marie A. Schroeder1, Lowri E. Cochlin1, Kieran Clarke1, George K. Radda1 1University of Oxford, Oxford, UK

Hyperpolarization of 13C-labelled metabolic substrates provides the MR signal necessary to visualize in vivo substrate uptake and metabolism in real time. This dynamic information could provide the basis for the kinetic modeling of cellular uptake and enzymatic activity. However, to achieve this end, an understanding of the physiological interactions between the hyperpolarized substrate and tissue is necessary. In this study, the relationship between initial pyruvate tracer concentration and the MR signal of pyruvate and its metabolic products was examined in the heart of living rats.

14:30 3195. In Vivo Detection of Hyperpolarized 15N Choline in the Rat Cristina Cudalbu1, Arnaud Comment2, Kai Uffmann, Ruud B. van Heeswijk, Chiara Perazzolo, Fiodar Kurdzesau2, 3, Sami Jannin2, Vladimir Denisov4, Deniz Kirik4, Jacques J. vna der Klink2, Rolf Gruetter, 5 1 Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland; 2Laboratory for Physics of Nanostructured Materials, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; 3Paul Scherrer Institute, Villigen, , Switzerland; 4Lund University, Sweden; 5Departments of Radiology, Universities of Lausanne and Geneva, Switzerland

The aim of the present study was to demonstrate the feasibility of detecting hyperpolarized 15N labeled Choline in vivo in the rat. All the 15N MRS data were acquired on a 9.4T system. 15N choline was polarized at 3.35T and 1.2K. The long T1 combined with the potential to observe hyperpolarized 15N Cho in vivo makes this compound useful for early detection of tumors and also for a potential utilization in the assessment of blood flow. To our knowledge the in vivo detection of hyperpolarized 15N has not been demonstrated to date. We conclude that it is feasible to detect hyperpolarized 15N in live animals.

15:00 3196. Localized Detection of Hyperpolarized [1-13C]Pyruvate and Its Metabolic Products in Rat Brain Dinesh K. Deelchand1, Isabelle Iltis1, Malgorzata Marjanska1, Chris Nelson1, Kamil Ugurbil1, Pierre-Gilles Henry1 1University of Minnesota, Minneapolis, Minnesota, USA

This work examines the feasibility of measuring 13C signals from hyperpolarized 13C metabolic products in the rat brain in vivo following i.v. injection of hyperpolarized [1-13C]pyruvate. Enhanced 13C resonances from pyruvate, pyruvate hydrate, lactate and alanine were observed. Comparison of unlocalized 13C spectra with 13C-localized LASER spectra suggests that a significant fraction of [1-13C]lactate signal arises from brain tissue.

15:30 3197. Detecting the Invisible: DNP-Enhanced Detection of 13C in Carboxyl Resonances of Rat Brain Extracts Chiara Perazzolo1, Arnaud Comment1, Kai Uffmann1, Ruud B. van Heeswijk1, Fiodar Kurdzesau1, 2, Sami Jannin1, Jacques J. van der Klink1, Rolf Gruetter1, 3 1Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; 2Paul Scherrer Institute, Villigen, Switzerland; 3Universities of Lausanne and Geneva,, Switzerland

13C spectra are largely used in MRS to investigate brain metabolism in vivo; hyperpolarization has been used to enhance the signal of a specific 13C tracer with the aim to observe metabolism. Brain extracts may yield important additional insight into the measurement of metabolic rates. The aim of the current study was to establish hyperpolarization of 13C in brain extract for the detection of low concentration 13C with intrinsically low sensitivity. To the best of our knowledge, for the first time a brain extract solution has been successfully hyperpolarized.

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14:00 3198. Hyperpolarized 13C Acetate Detection in the Rat Brain in Vivo Kai Uffmann1, Arnaud Comment1, Ruud B. van Heeswijk1, Chiara Perazolla1, Sami Jannin1, Fiodar Kurdzesau1, 2, J. A. Konter2, Patrick Hautle2, Ben van der Brandt2, Jacques J. van der Klink1, Rolf Gruetter1, 3 1Ecole Polytechnique Fédéral de Lausanne (EPFL), Lausanne, Switzerland; 2Paul Scherrer Institute, Villigen, Switzerland; 3Universities of Lausanne and Geneva, Switzerland

Hyperpolarized 1-13C-acetate was infused into three rats, followed by collection of 20 spectra (TR=3s). The decay of the enhanced signal of the tracer could be sampled. In an additional experiment performing spectroscopic imaging the localization of the acetate signal was proven to be in the brain. A T1 relaxation time of 20.7s of the labeled compound was derived by fitting the decay using a biexponential curve. Furthermore a resonance peak at 174.1ppm was observed, which followed the similar decay as the acetate signal. The origin of this peak remains to be investigated.

14:30 3199. Can Hyperpolarized 89Y Be Used as a Molecular Imaging Agent? Matthew E. Merritt1, 2, Crystal Harrison1, 2, Zoltan Kovacs1, Craig R. Malloy1, A Dean Sherry1, 2 1UTSW Medical Center, Dallas, Texas, USA; 2UT Dallas, Richardson, Texas, USA

Yttrium-89 is an NMR active nucleus with exceptionally long T1's but low sensitivity compared to protons. It is shown that dynamic nuclear polarization can be used to enhance 89Y sensitivity 250 to 1500-fold. Yttrium has similar coordination chemistry to gadolinium, and could potentially be used as a molecular imaging agent if bound to the appropriate ligand.

15:00 3200. Withdrawn

15:30 3201. Methyl Group Tunnelling and Dynamic Nuclear Polarization Martyn Paley1

This novel hyperpolarization method uses light with orbital angular momentum (OAM) to enable the direct hyperpolarization of liquids. The feasibility of this technique was verified experimentally by performing NMR spectroscopy on liquid sample (index matching oil, refractive index of 1.516) at 0.18T. A proton NMR signal was generated with an SNR of 5.3 (sample size = 30µL, polarization time = 70ms, FID measurement time = 8ms, 200ksamples, 20 averages). The resulting NMR spectra corresponded well with a standard MR spectroscopy measurement performed on a commercial 1.0T Philips Panorama scanner (PRESS sequence, FOV=1cm3, FA=90°, TE/TR=50/2500ms, NSA=24, BW=8000Hz, NP=16384). A tunnel magnetic resonance switched field experiment on zinc acetate shows generation of dynamic nuclear polarization without the use of microwave irradiation based on tunnelling methyl groups interacting with a free electron. 1University of Sheffield, Sheffield, UK

Molecular Imaging Agents & Techniques Hall D Tuesday 13:30-15:30

13:30 3202. A Novel Targeted Iron Oxide Nanocolloid Agent for T1 and T2* Imaging of Fibrin Using Conventional MR Techniques Shelton D. Caruthers1, 2, Angana Senpan1, Dipanjan Pan1, Mike J. Scott1, Patrick J. Gaffney3, Christian Stehning4, Jochen Keupp4, Patrick M. Winter1, Samuel A. Wickline1, Gregory M. Lanza1 1Washington University, St. Louis, Missouri, USA; 2Philips Medical Systems, Andover, Massachusetts, USA; 3St. Thomas' Hospital, London, UK; 4Philips Research Europe, Hamburg, Germany

A novel nanocolloid contrast agent with multiple iron-oxide crystals per nanoparticle (1240 μg Fe per g of emulsion) has been targeted to fibrin clot phantoms and human endarterectomy specimens in vitro. The agent can be visualized as the typical signal dearth on T2* imaging, but also as bright signal on conventional T1-weighted turbo spin echo imaging. The agent is constrained by size to the vasculature and is predicted to allow imaging to be performed within minutes post-injection.

14:00 3203. 19F Magnetic Resonance Imaging of Increased VCAM-1 Expression in the Kidneys of ApoE-Null Mice Using Targeted Perfluorocarbon Nanoparticles Richard Southworth1, Junji Chen2, Lei Zhang2, Megan Kaneda2, Huiying Zhang2, Samuel Wickline2 1King's College London, London, UK; 2Washington University School of Medicine, St. Louis, Missouri, USA

Vascular Cell Adhesion Molecule-1 (VCAM-1) is responsible for the tethering of leukocytes to the vascular lumen in early inflammation. It has been implicated in the pathogenesis of numerous inflammatory diseases, and therefore represents a potentially useful molecular imaging target. We have developed unique liquid perfluorocarbon nanoparticles which can be functionalised with homing ligands in their outer lipid layer, allowing us to target them to intravascular biomarkers of disease. These nanoparticles are capable of delivering a targeted payload of over 50,000 Gd atoms, or by virtue of their high 19F content (98% by volume), providing a quantifiable 19F MR signal. Here, we describe their use in specific visualisation and quantification of VCAM-1 expression in the kidneys of atherosclerotic ApoE-/- mice.

14:30 3204. First Results of an Ex-Vivo Experiment on Human Plaques Using a Contrast Agent Targeting Activated Platelets Dominik Paul1, Constatin von zur Mühlen1, Julia Möller1, Timo Spehl1, Christoph Bode1, Karlheinz Peter2, Dominik von Elverfeldt1 1University Hospital Freiburg, Freiburg, Germany; 2Baker Heart Research Institute, Melbourne, Australia

Targeted MRI contrast agents are gaining importance in clinical diagnostic. Here we present an experimental ex-vivo environment for the evaluation of target specific MRI contrast agents on human plaque tissue. The contrast agent consists of microparticles of iron oxide and single-chain antibodies targeting ligand-induced binding sites on activated glykoprotein IIb/IIIa-receptors. Specific target binding resulted in a clear signal drop in high resolution, high field T2 and T2* imaging and was verified by immunohistochemistry. The experimental setup proves to be a promising tool for pre-clinical research on target specific contrast agents.

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15:00 3205. Towards Dual-Mode Imaging of Vulnerable Plaques Ben Jarrett1, Bjorn Gustafsson1, Angelique Louie1 1UC Davis, Davis, California , USA

We have developed dual-mode imaging agents detectable by both MRI and PET for detection and diagnosis of plaque vulnerability. The probes are targeted to macrophages, whose density correlates with plaque vulnerability.

13:30 3206. Characterization of Signal Ehnacement Following the Intraperitoneal Injection of Gadolinium Based Contrast Agents Sharon Portnoy1, Jonathan Bishop1, Jun Dazai1, Shoshana Spring1, R.M. Henkelman1, 2 1Toronto Centre for Phenogenomics, Toronto, Canada; 2University of Toronto, Toronto, Canada

The objective of this investigation is to determine the enhancement time-course and dosage requirements in mice for intraperitoneally (IP) administered Gadolinium contrast agents. Although higher doses are required (~2.5 mmol/kg) and enhancement is slightly delayed, results suggest that IP injection may be an effective method for Gadolinium administration. The relative simplicity of IP contrast administration compared to traditional tail-vein injection makes this method a convenient alternative, particularly in longitudinal studies and high-throughput imaging of large numbers of mice.

14:00 3207. Fluorine-19 MRI of the Lung: First Human Experiment Ursula Wolf1, Alexander Scholz1, Maxim Terekhov1, Kerstin Muennemann1, Karl Kreitner1, Christian Werner1, Christoph Dueber1, Wolfgang Guenter Schreiber1 1Johannes Gutenberg University, Mainz, Germany

As fluorine-19 MRI of the lung appears to be a promising tool for the diagnosis of obstructive lung diseases such as COPD, efforts have been made to improve image quality and to develop a technique which can be safely and effectively used in humans. Since 1984, a lot of animal experiments have been performed using SF6, C2F6, C4F8, C3HF7, and CF4 as contrast gases. Here, we present the data of the first human experiment using up to 78% SF6. This experiment is an important milestone towards the use of fluorine-19 MRI in patients.

14:30 3208. In-Vivo Ultra-High Resolution Imaging of Small Vessels Using Improved Sensitivity and Long Circulation Time of FeCo-Graphitic Carbon Shell Nanocrystals Jin Hyung Lee1, Sarah Sherlock1, Masahiro Terashima1, Hisanori Kosuge1, Won Seok Seo1, 2, Yoriyasu Suzuki1, Michael V. McConnell1, Dwight G. Nishimura1, Hongjie Dai1 1Stanford University, Stanford, California , USA; 2Sogang University, Seoul, Republic of Korea

FeCo-Graphitic Carbon Shell Nanocrystals have been recently reported to have an unprecedented high relaxivity with multi-functional capabilities. In this paper, we demonstrate how the improved sensitivity provided by the high relaxivitiy combined with the long circulation time can be used to generate high-resolution in-vivo vessel images.

15:00 3209. Development of a New Series of Nitroimidazoles Probes for Oxygen Tension (pO2) Measurement by 1H Magnetic Resonance Spectroscopy Jesus Pacheco1, 2, Paloma Ballesteros2, Sebastian Cerdan1, Pilar Lopez-Larrubia1 1Instituto de Investigaciones Biomedicas "Alberto Sols"- CSIC, Madrid, Spain; 2Instituto Universitario de Investigacion - UNED, Madrid, Spain

Hypoxia is known to be an important physiological parameter determining tumour progression and malignancy. In this study, we report the synthesis and in vitro evaluation of a new series of nitroimidazolyl derivatives as quantitative pO2 markers. The NADPH:cytochrome P450 reductase enzymatic systems was found to reduced the probes only under anoxic conditions. Incubation of one of this derivative with C6 cells under different oxygen concentrations depicted clearly visible changes in the 1H-NMR spectrum at the probe, which depended on the degree of hypoxia.

13:30 3210. Targeted MR Imaging of CD44-Positive Breast Cancer Stem-Like Cell Phenotype Dmitri Artemov1, Wenlian Zhu1, Yoshinori Kato1, Marie-France Penet1, Farhad Vesuna1, Zaver Bhujwalla1, Venu Raman1 1Johns Hopkins University, Baltimore, Maryland, USA

Recently, a subpopulation of highly tumorigenic and drug resistant cancer cells was identified in multiple solid tumors, which is currently referred to as cancer stem-like cells. In breast cancer, these cells are characterized by high level expression of the cell surface receptor CD44 and decreased expression of another marker, CD24.. Here we have developed a CD44-targeted system for MR imaging of breast cancer stem-like cells and demonstrated the MR imaging of CD44 positive MDA-MB-231 human breast cancer cell in vitro.

14:00 3211. Nanoglobular Gd-DO3A Conjugates as Highly Effective MRI Contrast Agents Todd Kaneshiro1, Eun-Kee Jeong, Dennis Parker, Zheng-Rong Lu1 1University of Utah, Salt Lake City, Utah, USA

Novel macromolecular Gd(III) chelates with well-defined nanosizes and globular morphology were synthesized as highly effective MRI contrast agents. The nanoglobular MRI contrast agents resulted in significant blood and tumor enhancement at a substantially reduced dose, e.g. 10 µmol-Gd/kg.

14:30 3212. Manganese-Alginate Gels for Controlled-Release of Mn2+ Christian Brekken1, Ioanna Sandvig1, Olav Haraldseth1, Gudmund Skjåk-Bræk1, Yrr Mørch1 1NTNU, Trondheim, Norway

In the present study we aimed at designing alginate beads for controlled release of Mn2+. Both elemental analysis and swelling studies of the alginate gel beads showed great differences in the ion binding properties of alginate to manganese. Dynamic T1-weighted MRI of single alginate beads immersed into NaCl-solution showed that the Mn2+ release rate differed by a factor of up to ~100% between the 4 differently designed beads imaged. The results indicate that nano-fabrication of Mn-alginates can tailor-make biocompatible manganese delivery systems and hopefully help in introducing MEMRI in targeted contrast-enhanced MRI of otherwise toxicity-limited organs, such as the brain.

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15:00 3213. Novel Receptor-Targeted Nanoparticles for MR Imaging and Specific Delivery of Gene Therapy Panagiotis Kyrtatos*1, Michele Writer*, Anthony N. Price1, Stephen Hart, Mark F. Lythgoe1 1Institute of Child Health and Department of Medicine, University College London, London, UK

Multimodal nanoparticles offer a promising application as MRI contrast agents with therapeutic capabilities. Our group is developing a novel gene therapy vector, which utilises an anti-cancer targeting peptide for specific transfection of tumour cells with therapeutic genes. In addition, a Gd3+ moiety has been incorporated for non-invasive real-time monitoring of the delivery. Here we present a pilot in-vitro tumour cell study investigating the MRI properties of the vector, confirming its potential for both specificity of delivery of DNA to the target cells for gene therapy and also providing evidence of the MR contrast enhancement in targeted cells.

13:30 3214. MR Imaging of Breast Cancer Using the Folate-Receptor Targeted Contrast Agent P1133 Reinhard Meier1, 2, Tobias D. Henning1, Sophie Boddington1, Sidhartha Tavri1, Sandeep Arora1, Claire Corot3, Ernst J. Rummeny2, Heike E. Daldrup-Link1 1University of California San Francisco, San Francisco, California , USA; 2Technical University Munich, Klinikum Rechts der Isar, Munich, Germany; 3Guerbet, Paris, France

The purpose of this study was to assess the uptake of the new FR-targeted USPIO P1133 in breast cancers. In vivo studies demonstrated a progressive enhancement of central tumor areas with the FR-targeted USPIO P1133 in FR-positive MDA-MB-231 breast cancers. Corresponding SNR data were significantly higher for P1133 compared to P904B, indicating at least a component of FR-specific enhancement with P1133. The P1133 tumor uptake was not significantly inhibited by FFA in vivo, most likely due to the rapid FFA metabolism in the liver. Thus, the FR-targeted USPIO P1133 provides a significant and specific enhancement of FR-positive MDA-MB-231 breast cancers.

14:00 3215. Synthesis and Characterization of a Redox- And Light-Responsive MRI Probe Chuqiao (Tom) Tu1, Ryan Ngao1, Angelique Louie1 1UC Davis, Davis, California , USA

We have previously developed a gadolinium contrast agent that reversibly changes relaxivity properties in response to irradiation by different wavelengths of light. We here demonstrate that the contrast agent can also be modulated by reduction/oxidation. The mechanism for the relaxivity effects in response to redox appear to differ from the light induced response.

14:30 3216. Quantitative Molecular Imaging with a Combined Fluorescence Diffuse Optical Tomography and MRI System yuting lin1, Orhan Nalcioglu2, Gultekin Gulsen2 1University of California, Irvine, California , USA; 2University of California, Irvine, California , USA

An ideal molecular imaging technique should have both high sensitivity for molecular probes and also provide high-resolution images. Our solution to this demanding requirement is to employ a multimodality imaging strategy. In this study, we show the feasibility of using a combined MRI and optical fluorescence imaging approach to quantitatively resolve the fluorescence contrast agent concentration. The true fluorophore concentration was recovered only if the MRI anatomical information was employed.

15:00 3217. Real-Time Feedback Paradigm for Functional and Metabolic Imaging Using a Combined PET/MR Scanner: Proof of Concept Thomas Sheung Chee Ng1, 2, Daniel Procissi1, Andrey Demyanenko1, Yibao Wu3, Ciprian Catana4, Simon R. Cherry3, Andrew A. Raubitschek5, Russell E. Jacobs1 1California Institute of Technology, Pasadena, California, USA; 2University of Southern California, Los Angeles, California , USA; 3University of California, Davis, Davis, California , USA; 4Massachusetts General Hospital, Boston, Massachusetts, USA; 5City of Hope National Cancer Center, Duarte, California , USA

Positron Emission Tomography (PET) and Magnetic Resonance (MR) offer complementary functional and anatomic information that provide unique windows into biological processes. As well as integrating images in space and time, the combined PET/MR scanner offers the potential to perform real time analysis of multi-modal data that can feedback to direct further studies in a single imaging session. We demonstrate the feasibility of this paradigm. Mice implanted with tumor cells were imaged simultaneously with PET/MR. Functional data derived from the PET was used as a basis for 1H-MR spectroscopy studies, demonstrating metabolic heterogeneity within a tumor cell mass.

MRS of Cells, Body Fluids Hall D Wednesday 13:30-15:30

13:30 3218. [3-13C]Pyruvate: Useful Alternative to Labeled Glucose for In Vitro Metabolic Studies in Primary Mouse Hepatocytes Sven Gottschalk1, Michaela Hohnholt2, Dieter Leibfritz2, Marc Bilodeau1, Claudia Zwingmann1 1University of Montréal, Montréal, Canada; 2University of Bremen, Bremen, Germany

Application of stable isotope labeling in vitro is a powerful method to study metabolic pathways and fluxes. We applied [3-13C]pyruvate on primary mouse hepatocyte cultures to establish labeled pyruvate for metabolic studies and flux analysis in this cellular model. Our results show: [3-13C]pyruvate was metabolized by lactate dehydrogenase, alanine-/aspartate-aminotransferase, PC, PDH and subsequent metabolic pathways through the TCA-cycle. Considering that almost no 13C-NMR studies in isolated hepatocytes have been performed so far, labeled pyruvate will provide an important physiological substrate to assess hepatocellular pathways and the de novo synthesis of metabolites in these cells under normal and pathological conditions.

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14:00 3219. A Versatile NMR-Compatible Bioreactor for Alginate-Encapsulated Liver Cells Rex Errol Jeffries1, Kayvan R. Keshari, Chris Seagle, Peter Pediaditakis, Michael P. Gamcsik, John Kurhanewicz, Jeffrey M. Macdonald 1University of North Carolina, Chapel Hill, USA

Synopsis: A remodeled NMR-compatible bioreactor was used with electrostatic alginate encapsulation of hepatocytes to create a bioartificial liver ultimately designed for metabolomic studies. The 500 μ m diameter spherical encapsulates are well perfused and permit the use of 20% oxygen rather than the standard 95% oxygen. The 31P NMR spectra from a rat liver cell line, JM1, and primary rat hepatocytes were compared to oxygen uptake rates for bioenergetics.

14:30 3220. Metabolism of Colonic Mucosa in Patients with Ulcerative Colitis (UC) and Crohn’s Disease (CD): An NMR Study B Krithika1, S Kumar1, R R. Singh1, Uma Sharma1, V Ahuja1, G K. Makharia1, N R. Jagannathan1 1All India Institute of Medical Sciences, New Delhi, India

In vitro NMR spectroscopy demonstrated significant differences in the concentration of amino acids (isoleucine/leucine/valine, glutamic acid + glutamine, alanine), membrane components (choline, glycerophosphorylcholine, myoinositol), glycolytic product (lactate) in patients with active state of ulcerative colitis (UC) and Crohn’s disease (CD) compared to controls indicating a decreased protein and carbohydrate metabolism. In the remission state, levels of most of the metabolites were similar to controls. A significant difference in the concentration of formate was observed between patients with active states of UC and CD suggesting its potential as a biomarker for distinguishing UC and CD.

15:00 3221. Cellular Metabolism and Apoptosis – Dexamethasone, a Promising New Candidate to Intervene on the Metabolic Level Sven Gottschalk1, Michaela Hohnholt2, Dieter Leibfritz2, Claudia Zwingmann1, Marc Bilodeau1 1University of Montréal, Montréal, Canada; 2University of Bremen, Bremen, Germany

We have recently shown that the initial phase of the apoptotic process is associated with alterations in specific glucose metabolic pathways. The synthetic glucocorticoid Dexamethasone is known for its anti-apoptotic effects and impact on glucose metabolism (in particular, anaplerosis and gluconeogenesis). We therefore characterized the effects of Dexamethasone on hepatocellular metabolism with multinuclear NMR-measurements. Our results further support the strong relationship noted between changes in cellular metabolism and apoptosis. This paves the way toward the therapeutic modulation of cell metabolism in order to influence upon cell survival/death particularly in the context of liver injury.

Cell Labelling & Tracking Hall D Wednesday 13:30-15:30

13:30 3222. In Vivo Imaging of Endogenous Neural Stem Cells Labelled with a Ferumoxide-Polycation Complex Using a Low Field System Rachael Dobson1, 2, Patrizia Ferretti1, Mark Lythgoe1 1University College London, London, UK

Adult neural stem cells (NSC) migrate towards the olfactory bulb and differentiate into neurons. Ferumoxide-based contrast agents have been used to track the migration of exogenously-labelled NSC, there are limited methods that allow for longitudinal tracing of endogenous neural stem cells using MRI. In this study, two MRI contrast agents were used to label the endogenous population of NSC and neuroblasts in situ in the subventricular zone. Cell labelling and T2* contrast were assessed up to 28 days post-labelling using a low-field system. Cell migration was observed in vivo and ex vivo, and histology confirmed labelling of migrating neuroblasts.

14:00 3223. Quantification of Cell Trafficking in Vivo Using Magnetically Sensitive Histograms Christopher M. Long1, Hyam I. Levitsky1, Jeff W.M. Bulte 1Johns Hopkins University School of Medicine, Baltimore, Maryland, USA

Quantification of dendritic cell migration to lymph nodes in vivo is critical for evaluating the efficacy of tumor vaccines. We developed a new method based on magnetically sensitive histograms and cell-cell transfer of SPIO particles in vivo. It was found to correlate exceptionally well with ex vivo cell counts after magnetically activated cell sorting The method may be used to monitor the biological variability associated with cancer vaccination and to evaluate the efficacy of immunoadjuvants.

14:30 3224. In Vivo Stem Cell Tracking Using Magnetic Resonance Imaging in the Rat Genitalia of a Radical Prostatectomy Model Young Taik Oh1, Jang Hwan Kim1, Yong-Min Huh1, Myeong-Jin Kim1, Jin-Suck Suh1 1Yonsei University College of Medicine, Seoul, Republic of Korea

Erectile dysfunction is a major complication after radical prostatectomy for prostate cancer. There have been vigorous trials for improving erectile dysfunction but no satisfying method until now. Previous reports have shown that stem cell injection improved erectile function in a rat model erection dysfunction. However, they used the immunohistochemical stain for the evaluation of stem cell. A reliable in vivo imaging method to localize transplanted cells and monitor their restorative effects will enable a systematic investigation of cell therapy. Our results showed that in vivo stem cell tracking using MR imaging in a rat model of radical prostatectomy was feasible.

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15:00 3225. Comparison of Different Iron-Oxide Agent Detection Methods Using a Single Dataset Gopal Varma1, Richard Tavare1, Hannes Dahnke2, Stephen Keevil1, Tobias Schaeffter1 1King's College London, London, UK; 2Philips Research Laboratories, Hamburg, Germany

Detection of super-paramagnetic iron oxide can be achieved at varying sensitivities through its inherent negative contrast or by positive contrast methods. A single multi-echo dataset is used to compare T2* weighted imaging, R2* mapping, and positive contrast methods. In our study this includes inversion recovery on-resonance (IRON), gradient dephasing (“white marker”), and susceptibility gradient mapping (SGM). T2* images are found to be most sensitive to the smaller concentrations at short echo times (TEs), but high sensitivity of SGM and T2* imaging suggests a combination of these two methods is ideal. Data acquired for T2* images and SGM at 2 different TEs to address different concentrations would provide a more sensitive differentiation to the background.

13:30 3226. Stem Cell Treatment for Peripheral Arterial Disease - Comparison of Plain and Encapsulated X-Ray Visible Mesenchymal Stem Cell Transplants Dorota A. Kedziorek1, Wesley D. Gilson2, Kenyatta Cosby1, Matthias Stuber1, Bradley P. Barnett1, Royston C. Boston3, Grigorios Korosoglou4, Bernard E. Kohl1, Gary Huang1, Brady Sieber1, Aravind Arepally1, Jeff W.M. Bulte1, Lawrence V. Hofmann5, Dara L. Kraitchman1 1Johns Hopkins University, Baltimore, USA; 2Siemens, Baltimore, USA; 3University of Pennsylvania, Kennet Square, USA; 4University of Heidelberg, Heildelberg, Germany; 5Stanford University, USA

The resented work comapares plain and encapsulated Mesenchymal Stem Cell therapy in Peripheral Arterial Disease model. Non-invasive imaging demonstrated a more robust angiogenic response with encapsulated MSCs, while "naked" MSCs can incorporate into the vessel walls.

14:00 3227. Micrometer-Sized Particles of Iron Oxide (MPIOs) Enhanced Cardiac Imaging to Potentially Monitor Inflammatory Cells Infiltration in a Murine Model of Myocardial Infarction Yidong Yang1, 2, Ben Waghorn1, 2, Yuhui Yang1, Brianna Klein1, Nathan Yanasak1, Tom C-C. Hu1, 2 1Medical College of Georgia, Augusta, Georgia, USA; 2Georgia Institute of Technology, Atlanta, Georgia, USA

Inflammatory process plays an important role in myocardial injury and the subsequent recovery. In this study, we examined cell mobilization due to myocardial infarction post injection of micrometer-sized particles of iron oxide (MPIOs). MRI was performed to potentially visualize the migration and trafficking of inflammatory cells as well as to provide quantitative information. This technique indicates potential to track disease progression in a preclinical model of myocardial injury.

14:30 3228. In Vitro MR Thermometry on Magnetically Heated Iron Oxide Labeled Stem Cells Daniel Haddad1, Jochen Lorenscheit2, Markus Hildenbrand1, Meike Weber2, Regina Ebert2, Peter Michael Jakob1, 2 1MRB Research Center Magnetic-Resonance-Bavaria, Würzburg, Germany; 2University of Würzburg, Germany

Iron-oxide nanoparticles are commonly used as MR markers to label and track (stem) cells. Magnetic particle heating (magnetic field hyperthermia) can be used to heat the iron-oxide particles and thus the iron labeled stem cells. A proof-of-principle in vitro study shows that MR thermometry can be used to visualize the spatial and temporal heat distribution with high accuracy in the vicinity of iron-oxide labeled stem cells that were heated outside the MR spectrometer via magnetic particle heating. Since the heating capacity depends on the composition and structure of the material of interest, different types of iron-oxide particles yield different heating rates. The heating rates can also be controlled by varying the amount of iron-oxide incorporated in the cells.

15:00 3229. Tracking of Spio Labeled Natural Killer Cells to Epcam Positive Prostate Cancer with Mr Imaging Reinhard Meier1, 2, Sidhartha Tavri1, Tobias D. Henning1, Winfried S. Wels3, Rick Baehner1, Ernst J. Rummeny2, Heike E. Daldrup-Link1 1University of California San Francisco, San Francisco, California , USA; 2Technical University Munich, Klinikum Rechts der Isar, Munich, Germany; 3Chemotherapeutisches Forschungsinstitut, Frankfurt, Germany

Development and optimization of a technique for labeling of human natural killer (NK) NK-92 cells and genetically engineered NK-92-scFv(MOC31)-zeta cells, targeted to the Ep-CAM (epithelial cell adhesion molecule) on prostate cancer cells, with superparamagnetic iron oxides (SPIO). SPIO labeled NK cells were injected intravenously into rats with implanted Ep-CAM positive prostate cancers and the accumulation of the SPIO labeled NK cells in prostate tumors could be monitored with a non-invasive magnetic resonance (MR) imaging technique.

13:30 3230. Study on the Magnetic Relaxation of Superparamagnetic Nanotubes as Magnetic Resonance Imaging Contrast Agent xia Bai1, sang jun Son1, 2, shixiong Zhang1, wei Liu3, elaine k. Jordan4, joseph a. Frank4, Thirumalai Venkatesan1, Sang Bok Lee1 1university of maryland college park, college park, Maryland, USA; 2Kyungwon University, Republic of Korea; 3Philips Research North America, Briarcliff Manor, New York, USA; 4National Institutes of Health, Bethesda, Maryland, USA

This work describes the synthesis of magnetic nanotubes (MNTs) which is silica nanotube (SNT)/magnetic iron oxide nanoparticle (MION) composite with MIONs loaded in SNTs. This unique structure combines the easy chemistry for differential functionalization of the inner and outer surfaces of SNTs with the superparamagnetic characteristics of MIONs. The MNTs had well-controlled dimensions and retained a high saturation magnetization. It was proved that MNTs worked as an effective T2 magnetic resonance (MR) contrasting agent. The in vitro cell labeling was effective without showing significant cytotoxicity. Our results indicate that MNTs could be an ideal candidate for image-guided drug delivery.

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14:00 3231. MRI Detection of the Migrating Neuronal Precursors in Normal and Hypoxic-Ischemic Neonatal Rat Brain by in Vivo Cell Label with MPIO Jian Yang1, 2, Jian Xin Liu3, Gang Niu2, Yong Liu3, Ed X. Wu4 1Department of Electrical and Electronic Engineering, The University of Hong Kong , Hong Kong, People's Republic of China; 2The First Hospital of Xi'an Jiaotong University, Xi'an, People's Republic of China; 3The School of Medicine, Xi'an Jiaotong University, Xi'an, People's Republic of China; 4Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, People's Republic of China

In this study,10-day-old normal rats (n=6) and hypoxic-ischemic (H-I) neonatal rats (n=6) were injected with the micronsized iron oxide particles (MPIOs) into the anterior lateral ventricle. 2D and 3D gradient echo MRI was performed with a 7T animal scanner in hour 3, day 3, day 7 and day 14 after the MPIOs injection. Then animals were sacrificed for double staining with iron and mature neurons. In normal neonatal rat brain, the migrating pathway of the endogenous neural progenitor cells (NPCs) with MPIO is mainly along the rostral migratory stream to the olfactory bulb. In H-I neonatal rat brain, the migration of endogenous NPCs with MPIO is mainly toward injured boundary. MRI can facilely detect the above migrations in 2 weeks. Therefore, in vivo magnetic cell labeling of endogenous NPCs with MPIO and subsequently non-invasive, serial MRI monitoring should open up a new approach to probe into the mechanism of cell migration in the developmental brain under physiological and pathologic states.

14:30 3232. Quantitative Assessment of Magnetically Labeled Luciferase Positive Cells Using Multimodality Imaging April M. Chow1, 2, Kwan Man1, Jerry S. Cheung1, Tracy Y. Chow1, Ed X. Wu1 1The University of Hong Kong, Pokfulam, Hong Kong

Cellular imaging using magnetically labeled luciferase positive cells with multimodality imaging has found numerous biological applications. However, studies only involve imaging dual-labeled cells, tracking their migrations without quantification of local density of the dual-labeled cells. Quantitative analysis of cells after transplantation may allow more accurate assessment of cell delivery and subsequent distribution and migration, which can lead to more effective monitoring and optimization of therapeutic paradigms. In this study, we demonstrated that dual-labeled cells exhibited excellent linear correlations between cell concentration with photon flux and δR2* in vitro, illustrating that quantitative assessment of dual-labeled cells can be achieved.

15:00 3233. Comparison of 2 Different Tumor Cell Labeling Techniques for in Vitro MRI Characterization with New Iron Oxide Particles Olaf Saborowski1, Francesco Santini2, Melpomeni Fani3, Philippe Robert4, Sebastien Ballet4, Jean Sebastien Raynaud4, Robin Santus4, Johannes Froehlich3, Klaus Scheffler2, Georg Bongartz3, Helmut R. Maecke3 1University Hospital Basel, Basel , Switzerland; 2University Basel/University Hospital, Basel, Switzerland; 3University Hospital Basel, Basel, Switzerland; 4Guerbet Group, Aulnay-Sous-Bois, France

Iron oxide particles (SPIO and USPIO) are widely used for MRI-based cell labeling and tracking because they can be loaded on cells by simple protocols and provide high image contrast due to their large susceptibility effect. We compared 2 different cell labeling models (AGAR and Ficoll) in human KB cells. Both presented cell labeling methods (AGAR and Ficoll model) are feasible for in vitro MR characterization of KB tumor cells at 1.5, 2.35 and 3T. Ficoll method is easier to perform because it does not need a heating procedure for preparation without air bubbles as compared to AGAR method.

13:30 3234. Longitudinal Tracking and Quantification of T Cells Using in Vivo 19F MRI Mangala Srinivas1, Michael S. Turner2, Penelope A. Morel2, Jelena M. Janjic1, David H. Laidlaw3, Eric T. Ahrens1, 4 1Carnegie Mellon University, Pittsburgh, Pennsylvania, USA; 2University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA; 3Brown University, Providence, USA; 4Pittsburgh NMR Center for Biological Research, Pittsburgh, Pennsylvania, USA

19F MRI was used to track T cells in a murine model of acute inflammation for up to 21 days. Quantification of total 19F signal in the DLN, and hence apparent cell numbers, from the in vivo data showed 2.1x106 ± 9x105 apparent cells at day 2 and 3.6x106 ± 9x105 at day 7 post-transfer in the draining lymph node. The murine inflammation model can be applied to study the effect of therapeutics on T cell trafficking. The in vivo 19F platform developed can readily be extended to other cells types including, immunotherapeutics or stem cells.

14:00 3235. A Novel Bimodal Fluorescent and Paramagnetic Lipid for Cell Labelling and Tumour Magnetic Resonance Imaging Nazila Kamaly1, Tammy Louise Kalber1, Jimmy D. Bell1, Michael R. Jorgensen1, Andrew David Miller1 1Imperial College London, London, UK

A novel bimodal fluorescent and paramagnetic lipid, Gd.DOTA.Rhoda.DSA was synthesised. Cationic and neutral PEGylated bimodal liposomes were formulated for cell labelling and tumour imaging respectively. Effective IGROV-1 (human ovarian carcinoma) cell labelling was demonstrated in vitro post incubation of cells with the cationic liposome formulations containing Gd.DOTA.Rhoda.DSA. The enhanced permeation and retention (EPR) effect of tumour tissue was exploited post-injection of the neutral PEGylated liposomes in mice to image IGROV-1 xenografts. Tumour T1 values were reduced 14-24 h post-injection of the bimodal liposomes by a substantial 65%. These MRI findings were supported by fluorescence findings co-validating the presence of the bimodal liposomes/lipid within tumour tissue.

14:30 3236. Bimodal Intracellular Nanoparticles Based on Quantum Dot Technology for High Field MR Microscopy at 21.1 T Jens Thorvald Rosenberg1, 2, Joshua M. Kogot1, Goeffery F. Strouse1, Samuel Colles Grant1 1The Florida State University, Tallahassee, USA

A bimodal contrast agent for the intracellular transfection of mammalian cells has been optimized for high magnetic field MR imaging at 21.1 T. With a fluorescent InP/ZnS quantum dot as a substrate, a peptide-bound lanthanide (Dy3+) component has been added to generate MR contrast. The CAAKA–DOTA-Ln3+-Qdot agent displays strong MR contrast enhancement for all relaxation mechanisms, but the strongest contrast for intracellular loading is seen with T2/T2* weighting. Utilizing this agent, Chinese Hamster Ovary (CHO) cells were transfected, with MR and confocal images displaying contrast enhancement and the intracellular localization of nanoparticles.

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15:00 3237. 19F NMR Molecular Imaging: Cell Labeling With Emulsified Perfluoro-15-Crown-5-Ether Samir Mulla-Osman1, Henrike Goetze2, Ute Bommerich3, Johannes Bernarding 1University of Magdeburg, Magdeburg, Germany; 2University of Magdeburg, Germany; 3Leibniz Institute for Neurobiology, Germany

Monitoring 19F-labelled cells is an important new technique to evaluate in vivo the fate of implanted cells such as in stem cell therapy. The use of 19F-marker substances such as perfluorocarbons (PFC) has been explored by 19F spectroscopy and magnetic resonance imaging (MRI) for cell tracking. We present first results of single volume selective spectroscopy of fibroblasts, which have been labeled with perfluoro-15crown-5-ether (PFCE) emulsion.

MRS Methodology Hall D Thursday 13:30-15:30

13:30 3238. MEGA-Editing of Spermine/Spermidine in Healthy Human Prostates Using External Phased-Array Coil Assembly Michael Albert Thomas1, S.Sendhil Velan2, Saadalah Ramadan3, 4, Nagarajan Rajakumar1, Daniel J. Margolis1, Maria Ana Gomez1, Steve S. Raman1, Carolyn E. Mountford3, 4 1UCLA, Los Angeles, California , USA; 2West Virginia University, Morgantown, West Virginia, USA; 3Brigham and Women's Hospital, Boston, Massachusetts, USA; 4Harvard Medical School, Boston, Massachusetts, USA

Polyamines such as spermidine and spermine play a critical role in cell proliferation and differentiation in cancer. Overlap of metabolite resonances is a major concern in conventional one-dimensional (1D) MR Spectroscopy (MRS), hence spectral-editing techniques either based on signal subtraction or multiple-quantum filter have been proposed and tested in human brain in vivo. A goal of this work was to implement a MEGA-based spectral editing sequence on a 3T MRI scanner, to optimize the technique using prostate phantom, and to evaluate the feasibility of detecting spermine/ spemidine in healthy human prostates using an external phased-array matrix coil assembly.

14:00 3239. Optimized MRS of Neurotransmitters: How Far Do You Need to Go? Paul Mullins1, 2, Hongji Chen2, Jing Xu2, Arvind Caprihan2, Charles Gasparovic2, 3 1Bangor University, Bangor, UK; 2The MIND Research Network, Albuquerque, New Mexico, USA; 3University of New Mexico, Albuquerque, New Mexico, USA

Standard and optimized MRS sequences for the detection of Glutamate and other neurotransmitters are compared for test re-test reliability.

14:30 3240. High Speed Multi-Voxel Thermography with Free Induction Decay Echo Planar Chemical Shift Imaging Matthew A. Neimark1, Scott Henneman2, Yingli Yang2, Jae Choi2, Angelos Aristeidis Konstas3, Melvyn B. Ooi, Hamed Mojahed2, Andrew F. Laine2, John Pile-Spellman2, Truman R. Brown2 1Columbia University, New York, New York, USA; 2Columbia University, New York, USA; 3Massachusetts General Hospital, Boston, USA

In this study, we present a fast method of performing spectroscopic imaging using free induction decay echo planar chemical shift imaging (FID EP-CSI). This technique was performed on a phantom made up of Ringer’s lactate and 10 mM NAA. The phantom was cooled from 38 to 29 C while temperature was continuously monitored, and 13 FID EP-CSI acquisitions were performed. Each acquisition was 28 seconds. This is 12 times faster than conventional CSI. For voxels in a central region, the overall regression for NAA-H2O difference Δ NAA-H2O) vs. temperature (±95% confidence intervals) was T=(100.67±1.07 Δ NAA-H2O+300.36±2.86 (R2=0.9967; rms=0.16 C).

15:00 3241. Fully Automated Shimming for High Lipid Regions Using Phased Arrays at 3T Gamaliel Isaac1, Jeremy jeremy.magland@upenn.edu Magland, Hoby Patrick Hetherington2 1University of Pennsylvania, Philadelphia, Pennsylvania, USA; 2Yale University, New Haven, Connecticut, USA

We have developed a robust fully automated method for shimming regions of the body with high lipid content which is compatible with phased array detection. The method utilizes multi evolution delay B0 maps to generate high accuracy while retaining a large bandwidth for poor starting homogeneity. The method includes an embedded Dixon image to identify fat and water content such that the chemical shift due to lipid is corrected for allowing for the use of arbitrary evolution times. To demonstrate the method we have applied it to shim the human calf at 3T on a Siemens Trio system.

13:30 3242. SVD 8-Channel Coil Combine for 2D Chemical Shift Imaging (CSI) MRI Mithun Diwakar1, Mingxiong Huang1, 2, Roland R. Lee1, 2, Rebecca J. Theilmann1 1UCSD, La Jolla, California , USA; 2VA San Diego Healthcare System, San Diego, California , USA

This work describes a novel method for combining 2D Chemical Shift Imaging (CSI) data recorded by 8 independent phased array coils (8-channel GE head coil). Singular Value Decomposition (SVD) is a form of dominant mode analysis that can be used to combine time decay signals. The work was carried out on a phantom containing physiologic concentrations of key metabolites found in the brain (NAA, Ch, Cr). The advantages of SVD over conventional methods of combining signals from multiple coils include preservation of phase-information, automatic zero-order phasing, and no need of a priori information.

14:00 3243. Improved Spectral Quality Through Enhanced Shimming on a Clinical Platform at 3T and 7T Ralf Mekle1, 2, Giulio Gambarota1, Vladimir Mlynarik1, Rolf Gruetter1, 3 1Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland; 2University of Lausanne, Lausanne, Switzerland; 3Universities of Lausanne and Geneva, Lausanne and Geneva, Switzerland

Reliable localized shimming is an essential prerequisite for obtaining high-quality MR spectra, especially at higher fields ≥3T). For the first time, the fast automatic shimming technique by mapping along projections (FASTMAP) and its descendant FASTESTMAP were implemented on a clinical platform of a 3T and a 7T system. In vivo proton spectra from various brain regions were acquired and showed excellent quality due to the enhanced local field homogeneity resulting from improved shimming with FASTMAP/FASTESTMAP that translated into reduced water and metabolite linewidths at both field strengths.

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14:30 3244. Application of Forward Linear Prediction Method to High-Resolution NMR Spectra in Inhomogeneous Fields Hai Feng1, 2, Zhiwei Chen1, Shuhui Cai1, Xiaohong Wang1, Ji Feng3, Zhong Chen1 1Xiamen University, Xiamen, People's Republic of China; 2Institute of Physics, Chinese Academy of Sciences, Beijing , People's Republic of China; 3Institute of Physics, Chinese Academy of Sciences, Beijing, People's Republic of China

The forward linear prediction (LP) method was applied to deal with 2D intermolecular double quantum coherence spectra from inhomogeneous fields. The results show that compared to normal discrete Fourier transform, the use of forward LP extrapolation can shorten sampling time by a factor of eight or more at the same level of sensitivity and resolution. It can effectively extend the data sets acquired from inhomogeneous fields even for shorter data records and lower signal-to-noise ratio.

15:00 3245. High-Quality MR Spectroscopy of the Human Brain with Full Signal Intensity at Echo Times Below 6 Ms on a Clinical Platform at 3T and 7T Ralf Mekle1, 2, Vladimir Mlynarik1, Giulio Gambarota1, Martin Hergt3, Gunnar Krueger3, Rolf Gruetter1, 4 1Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland; 2University of Lausanne, Lausanne, Switzerland; 3Siemens Medical Solutions-CIBM, Lausanne, Switzerland; 4Universities of Lausanne and Geneva, Lausanne and Geneva, Switzerland

The implementation of the spin echo full intensity acquired localized (SPECIAL) spectroscopy technique on a clinical platform was taken to the next level by combining interleaved water suppression (WS) and outer volume saturation (OVS), optimized sequence timing, and large B1 fields producing coils in addition to improved shimming. High-quality single voxel spectroscopy (SVS) data of the human brain were acquired at TEs below 6 ms on 3T and 7T systems. The high SNR of the spectra enabled reliable metabolite quantitation at both field strengths. Moreover, the enhanced sensitivity at the higher B0 field allowed a twofold reduction in scan time.

13:30 3246. Automating Brain Tumour Classification Using High Resolution Magic Angle Spinning Data Jean-Baptiste Poullet1, Daniel Monleon2, M. Carmen Martinez-Bisbal3, 4, Bernardo Celda3, 4, Sabine Van Huffel5 1Katholieke Universiteit Leuven , Leuven, Belgium; 2Fundación Investigación Hospital Clínico Universitario Valencia, Valencia, Spain; 3University of Valencia, Spain; 4Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Valencia, Spain; 5Katholieke Universiteit Leuven, Leuven, Belgium

The limited success of in vivo MRS to classify some brain tumor types tends to encourage the use of other data types. Thanks to their narrow line widths and their large signal-to-noise ratios, high resolution magic angle spinning (HR-MAS) data provides much more information than in vivo MRS. Since biopsy extraction is a routine procedure in the clinical practice, incorporating HRMAS in the decision system is a reasonable solution to improve brain tumor diagnosis. This study propose a fully automated procedure to classify HR-MAS spectra.

14:00 3247. Proton Decoupled 31P MRS of Head and Neck Tumors in Vivo at 1.5T and 3T Sungheon Kim1, Sanjeev Chawla1, Laurie A. Loevner1, Harry Quon1, Eric J. Sherman1, Gregory S. Weinstein1, Harish Poptani1 1University of Pennsylvania, Philadelphia, USA

The purpose of this study was to implement proton decoupled 31P MRS at 3T for assessing smaller tumors and to investigate its feasibility in predicting treatment response in head and neck tumors. Proton decoupled 31P MRS data were acquired from eleven patients who were treatment naïve. Substantial increase in SNR with smaller voxel sizes was achieved at 3T as compared to 1.5T. In a small cohort of patients, studied at 1.5T, 31P MRS studies partial responders exhibited higher PME/β NTP and PDE/β NTP ratio than complete responders indicating the potential of 31P MRS in prediction of treatment response.

14:30 3248. In Vitro Metabolites Limit of Detection by Localised NMR Spectroscopy Using Micro Coils Nicoleta Baxan1, Aziz Kadjo1, Guillaume Pasquet1, Jean-François Chateaux1, André Briguet1, Pierre Morin1, Danielle Graveron-Demilly1, Latifa Fakri-Bouchet1 1Université Lyon1, Villeurbanne, France

We present a new concept of receiver planar micro coil fabricated by electroplating technique. The innovative part of this work concerns: - Implemented MR instrumentation at micro-scale, - Restricted volumes detection by MR spectroscopy and imaging. The spectrum of a solution containing eleven MR-observable 1H metabolites in human brain (50 mM) is presented, the concentration limit of detection (LODc) for the Choline and NAA case are estimated at 3.3 mM and 10.4 mM respectively. The measurements reproducibility was established using six micro coil prototypes. The micro coils performance improvement open the way to highly spatially resolved explorations on animal model.

15:00 3249. Diffusion-Weighted 1H NMR Single Voxel Spectroscopy at 3T and 7T Daniela Wagegg1, Ralf Lützkendorf2, Wolfgang Dreher3, Claus Tempelmann4, Jörg Stadler5, Johannes Bernarding2 1Institute for Biometry and Medical Informatics, Medical Faculty, University of Magdeburg, Magdeburg, Germany; 2Institute for Biometry and Medical Informatics, Medical Faculty, University of Magdeburg, Magdeburg, Germany; 3Department of Biology and Chemistry, University of Bremen and Center for Advanced Imaging (CAI), Bremen, Germany; 4Institute for Neurology II, Medical Faculty, University of Magdeburg, Magdeburg, Germany; 5Leibniz Institute for Neurobiology, Magdeburg, Germany

We implemented Diffusion-weighted Single Voxel Spectroscopy on a 3T- and 7T-MR-Scanner. The Sequence was based on a STEAM-Sequence. The DW-gradients where applied simultaneously in each direction. In phantom studies, this allowed the calculation of the ADC values of several brain metabolites successfully.

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Non-Proton MRI Hall D Thursday 13:30-15:30

13:30 3250. Sodium Mapping in Focal Cerebral Ischemia in the Rat by Quantitative 23Na MRI Victor E. Yushmanov1, Boris Yanovski1, Alexander Kharlamov1, George LaVerde2, Fernando E. Boada2, Stephen C. Jones1 1Allegheny-Singer Research Institute, Pittsburgh, Pennsylvania, USA; 2University of Pittsburgh, Pittsburgh, Pennsylvania, USA

23Na twisted projection MRI was validated as a quantitative technique to assess local brain sodium concentration ([Na+]br) every 5.3 min after MCAO. The MRI protocol included a 0.4-ms echo-time, a B1 mapping, and 0-154 mM NaCl calibration standards. [Na+]br values were obtained by MRI and flame photometry in exactly the same ROIs of ~0.5 mm3 size. The Bland-Altman comparison of the two techniques in normal and ischemic cortex and caudate putamen of seven rats yielded a mean bias and limits of agreement of -4%±42% of average. A linear increase in [Na+]br was observed at 1-6 hours after MCAO.

14:00 3251. Sodium MRI with Triple Quantum Filter and Inversion Recovery at 7T Guillaume Madelin1, Niels Oesingmann2, Glyn Johnson1, Alexej Jerschow1, Matilde Inglese1 1New York University, New York, New York, USA; 2Siemens Medical Solutions USA, New York, New York, USA

This study demonstrates the feasability of Sodium MRI at 7T with Triple Quantum Filter (TQF) and Inversion Recovery (IR) in differentiating mobile vs. less mobile 23Na nuclei in phantoms. The combination of TQF and IR can give complementary informations about the sodium environment and allow a better differentiation of the intracellular and extracellular compartments in biological tissues. Future studies will focus on TQF and IR 23Na MRI on human brain in vivo at 7T in order to assess the intracellular sodium concentration, with the goal of localizing pathologies.

14:30 3252. Clean Separation of Bound vs. Free Sodium by 23Na Inversion Recovery Peng Rong1, Ravinder R. Regatte2, Alexej Jerschow1 1New York University, New York , New York, USA; 2New York University, New York, New York, USA

Monitoring the bound sodium pool often allows one to characterize tissue disorders, such as osteoarthritis, or cell dysfunction. Separation methods have been used based on residual quadrupolar interactions, or slow molecular tumbling. In the current study, we demonstrate the feasibility of employing the inversion recovery (IR) sequence to selectively detect the bound or the free sodium pools in cartilage tissue. The advantages of this method are its simplicity, the ability to selectively detect either the ordered or free sodium signal, the use of only a small phase cycle, and the independence of residual quadrupolar couplings.

15:00 3253. 23Na DQF Signal Induced by Paramagnetic Shift Reagents: Dependence on the Pseudo-Contact Shift Peng Rong1, Gil Navon2, Alexej Jerschow1 1New York University, New York , New York, USA; 2Tel Aviv University, Tel Aviv, Israel

23Na NMR/MRI in combination with paramagnetic shift agents is often used to separate the intra- from the extracellular sodium components. In addition to shifts, we recently reported relaxation effects which lead to the appearance of double-quantum coherences in isotropic phases and without slow motion. Here we show that these effects correlate with the pseudo-contact shift induced by the agents by examining the effects of the LnDOTP series.

13:30 3254. Sodium MRI Using a Density Adapted 3D Radial Acquisition Armin Michael Nagel1, Frederik Bernd Laun1, Marc-André Weber1, Lothar Rudi Schad 1German Cancer Research Center, Heidelberg, Germany

A density adapted 3D Radial sampling scheme (DA-3D-RAD) was implemented. The readout gradients of the DA-3D-RAD are switched constantly up to a k-space radius k0. Beyond this radius the gradient’s amplitude is reduced such that the sampling density in all spherical shells is kept constant. The benefits for sodium MRI compared to conventional 3D Radial sampling are demonstrated. In vivo sodium brain and phantom imaging was performed. This technique leads to a higher SNR compared to conventional radial sequences and improved resolution.

14:00 3255. Sodium Imaging on a Whole-Body 7T Scanner: SNR and Resolution Benefits Yongxian QIAN1, Yik-Kiong Hue1, Tiejun Zhao2, Tamir S. Ibrahim1, Fernando E. Boada1 1University of Pittsburgh, Pittsburgh, Pennsylvania, USA; 2Siemens Medical Solutions USA, Pittsburgh, Pennsylvania, USA

This study demonstrates sodium (23Na) images of a healthy human brain acquired on a whole-body 7T scanner. The signal-to-noise ratio (SNR) of the 7T images was increased by a factor of 3.5 in comparison with the images acquired on a 3T scanner with the same acquisition parameters. The SNR gain immediately resulted in an increase in spatial resolution of the 7T image from 3.44mm to 1.72mm.

14:30 3256. 31P Imaging of the Human Brain with Balanced SSFP - Preliminary Results Jochen Leupold1, Roza Umarova2, Jürgen Hennig1, Cornelius Weiller2, Holger Kaube2 1University Hospital Freiburg, Dept. of Diagnostic Radiology, Medical Physics, Freiburg, Germany; 2University Hospital Freiburg, Dept. of Neuroradiology, Freiburg, Germany

Magnetic Resonance Spectroscopy of 31P is a promising tool for the examination of several pathologies and metabolic processes. A beneficial reduction of total scan time could result from utilisation of fast pulse sequences, which can acquire spatial and spectroscopic information at the same time. We show preliminary results of imaging 31P in the brain with a balanced SSFP sequence, as this sequence has potential to be the basic signal generating sequence in several fast spatial-spectroscopic methods due to its high steady state signal.

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15:00 3257. Assessment of SNR and Detection Sensitivity of F-UTSI Muhammed Yildirim1, 2, Jochen Keupp3, Klaas Nicolay2, Rolf Lamerichs1 1Philips Research, Eindhoven, Netherlands; 2Eindhoven University of Technology, Eindhoven, Netherlands; 3Philips Research, Hamburg, Germany

F-uTSI (Fluorine ultrafast Tutbospectroscopic Imaging) is a Turbo Spin Echo (TSE) based method developed for imaging and detection of 19F based contrast agents by avoiding the well known chemical shift. Here, the preliminary results of performance assessment of the two basic variants of the method employing cartesian and pseudo-radial sampling of the k-space are presented. A small part of the potentially large parameter space was explored for two different perfluorocarbon compounds; perfluoroctyl bromide (PFOB) and perfluoro crown teher (PFCE), by altering the field the field of view and TR and the corresponding detection limits are investigated.

Measurement of Perfusion & Permeability Using Contrast Agents Hall D Monday 14:00-16:00

14:00 3258. Sampling the Arterial Input Function in T1 Weighted Dynamic Contrast Enhanced Perfusion Adam Espe Hansen1, 2, Henrik Bodil Wiberg Larsson1 1Glostrup Hospital, University of Copenhagen, Denmark

When using dynamic contrast enhanced (DCE) MRI to assess cerebral blood flow (CBF), correct determination of the arterial input function (AIF) is critical to CBF quantification. With T1-weighted DCE-MRI, we demonstrate the result of the partial volume effect (PVE) on CBF quantification in vivo. The larger vasculature can easily be identified and a PVE on the AIF can be introduced by displacing the AIF from the vessel centre. We further propose and test a method we denote venous normalization to compensate for PVE. This method might in particular be utilized to correct local arterial input functions.

14:30 3259. Correcting Susceptibility Artifacts in Arterial Input Function (AIF) for Dynamic Contrast Enhancement Magnetic Resonance Imaging (DCE-MRI) at 3T Poe-Jou Chen1, Wei-Ting Zhang2, Rakesh K. Jain3, T T. Batchelor3, A Gregory Sorensen2 1Massachusetts Institute of Technology, Cambridge, Massachusetts, USA; 2Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, USA; 3Massachusetts General Hospital, Charlestown, Massachusetts, USA

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is a non-invasive imaging technique that has the ability to study tumor vascular functions. It has been widely used for a range of clinical oncologic applications including cancer detection, grading, and evaluation of therapeutic response. Unfortunately, in high field MRI (3T), the image signal is prone to susceptibility effects due to the increased relaxivity of contrast agent. In this abstract, we propose a novel method that could fully compensate the susceptibility effect and restore the full range of plasma concentration dynamic curve. The results demonstrated that, despite severe T2* effects embedded in the DCE-MRI data, the technique is able to reconstruct the plasma concentration time course and provide us a more accurate vascular input function

15:00 3260. A Blood Circulatory Model to Estimate the Arterial Input Function in MR Brain Perfusion Studies Hassan Bagher-Ebadian1, 2, Kourosh Jafari-Khouzani1, Hamid Soltanian-Zadeh1, 3, James R. Ewing1, 4 1Henry Ford Hospital, Detroit, Michigan, USA; 2Amir-Kabir University of Technology, Tehran, Iran; 3University of Tehran, Tehran, Iran; 4Oakland University, Rochester, Michigan, USA

A mathematical model of Contrast Agent(CA) concentration in the circulatory system as a function of time is of interest since it may allow the description of the AIF based on the Intravenous (IV) injection function In this study, as a building block, the concentration-time profile in the circulatory system for each compartment was modeled by simple physical and pharmacokinetic assumptions using the Fick equation and Kety’s model. A complete model of the CA concentration as a function of time in the circulatory system was then constructed by combining those building blocks using typical flow and volume parameters for the various compartments. Using a model of the IV bolus injection, its results were compared to MR perfusion (T2*) signal, indicate that this model is a good candidate to be used to define a cost function for detection of the AIF in MR brain perfusion studies.

15:30 3261. The Use of Phase to Measure the Arterial Input Function for Quantitative T1-Weighted DCE-MRI in Human Brain Tumors Claire Foottit1, Greg O. Cron2, Matthew Hogan2, Thanh Nguyen2, Ian Cameron, 12 1Carleton University, Ottawa, Canada; 2Ottawa Health Research Institute, Ottawa, Canada

When measuring perfusion quantitatively in tumors with dynamic contrast-enhanced T1-weighted MRI, it can be challenging to measure the arterial input function (AIF) in large vessels. Blood flow and saturation effects can lead to incorrect conversion of signal magnitude to contrast agent concentration. The signal phase, however, is largely immune to such effects, potentially providing improved AIF measurement with no added imaging time or pulse sequence modification. Here, we used this technique to measure quantitative perfusion (Ktrans) in human brain tumors.

14:00 3262. Utilization of Principal Component Analysis for Improved Perfusion Measurements in Highly Undersampled Radial DCE-MRI Junyu Guo1, Mark A. Rosen1, Hee Kwon Song1 1University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA

We investigate the feasibility and accuracy of principal component analysis (PCA) for radial DCE-MRI. It is shown that with judicious selection of principal components, PCA can effectively remove image streaking and reduce noise in a highly undersampled radial DCE-MRI data set, permitting accurate, pixel-wise measurement of the perfusion parameters.

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14:30 3263. Assessment of Image Reconstruction Methods for Subsampled DCE-MRI Florian Knoll1, Franz Ebner2, Stephen Keeling3, Rudolf Stollberger1 1TU Graz, Graz, Austria; 2Medical University Graz, Graz, Austria; 3University of Graz, Graz, Austria

Undersampled imaging techniques, in combination with advanced image reconstruction methods like HYPR or parallel imaging, have the potential to deliver high resolution DCE-MRI data sets in spatial and temporal domain, which can be used for the identification of pharmacokinetic parameters. It is, however, not clear to which extent these techniques change the time course of contrast enhancement, in particular for the arterial input function. The performance of four state of the art reconstruction methods is evaluated in this work. It is shown that the estimation of pharmacokinetic parameters can be improved significantly using these undersampled imaging techniques.

15:00 3264. Accelerating Dynamic MRI with Efficient Multiple Acquisitions by SPEED Using Shared Information Zheng Chang1, Jim Ji2, Qing-San Xiang3, Fang-Fang Yin1 1Duke University, Durham, USA; 2Texas A&M University, College Station, Texas, USA; 3University of British Columbia, Vancouver, Canada

The efficient multiple acquisition method using Skipped Phase Encoding and Edge Deghosting (SPEED) has been successfully demonstrated in water-fat imaging with double acquisitions. In this work, it is further developed to accelerate dynamic MRI. In dynamic MRI, multiple acquisitions of different frames are spatially correlated, and thus share similar spatial information. By taking advantage of the shared information, dynamic MRI is accelerated by SPEED with factors greater than that achievable with a single acquisition. In this work, a dynamic contrast enhanced mice tumor study is accelerated by a factor of 2, with results comparable to the images without acceleration.

15:30 3265. Rapid Steady State T1 Method for Cerebral Blood Volume Fraction Mapping Using SINEREM as Contrast Agent and a Three Dimensional Projection Reconstruction Acquisition Mode Adriana Teodora Perles-Barbacaru1, Laurent Lamalle1, Emmanuel Barbier1, Christoph Segebarth1, Hana Lahrech1 1UMR-S 836 INSERM-UJF-CEA Functional & Metabolic Neuroimaging, La Tronche Cedex, France

The USPIO SINEREM is used for cerebral blood volume fraction (CBVf) mapping with the Rapid Steady State T1 (RSST1) method. A steady state signal for at least one hour is obtained in rats after an intravenous injection of 0.2 mmol/kg SINEREM and was exploited for CBVf mapping in healthy and RG2 glioma bearing rats with the RSST1 method in a 3D projection reconstruction acquisition mode enabling short echo time and with a susceptibility based steady state method for comparison. In opposite to results reported for the C6 tumor model, SINEREM seems to leak from the microvasculature in the RG2 tumor model.

DTI of the Damaged Brain Hall D Monday 14:00-16:00

14:00 3266. Serial Changes in Corpus Callosum Diffusion Tensor Imaging (DTI) Metrics in Moderate Traumatic Brain Injury (TBI) and Its Correlation with Neuro-Cognitive Functions Mazhar Husain1, Raj Kumar1, Rakesh K. Gupta2, Khader M. Hasan3, Mohammad Haris2, Atul Agarwal1, Ponnada A. Narayana3 1Chhatrapati Shahuji Maharaj Medical University, Lucknow, India; 2Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India; 3University of Texas Medical School at Houston, Houston, USA

Serial DTI within 2 weeks and at 6 months after TBI was performed on 38 patients with TBI [frontal (n=12), temporal (n=6), fronto-temporal (n=9) and multifocal (n=11)]. Neuropsychological tests (NPT) were performed at follow-up study and 30 age/sex matched controls. DTI was also performed in controls. The fractional anisotropy (FA) and mean diffusivity (MD) were quantified from different region of the corpus callosum (CC) in patients and controls. Decreased FA in callosal regions on follow-up study compared to controls was observed in different groups. We conclude that widespread primary abnormalities in acute stage and secondary damage after 6 months in the CC can be demonstrated on DTI. These DTI abnormalities significantly correlate with some of the NPT.

14:30 3267. Cerebral Diffusion Tensor Imaging (DTI) and in Vivo Proton MR Spectroscopy (PMRS) in Patients with Fulminant Hepatic Failure (FHF) Rakesh K. Gupta1, Sona Saksena1, Vijan Rai1, Vivek Anand Saraswat1, Ram KS Rathore2, Ankur Purwar2, Manoj Kumar1, M A. Thomas3 1Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India; 2Indian Institute of Technology, Kanpur, India; 3David Geffen School of Medicine at UCLA, Los Angeles, USA

In vivo PMRS and DTI data were acquired from FHF patients (n=10) and controls (n=10). Five of the 10 patients, had a repeat imaging after three weeks. N-acetylaspartate, choline (Cho), glutamine (Gln), glutamine/glutamate (Glx), and myoinositol ratios were calculated with respect to creatine (Cr). Fractional anisotropy (FA) and mean diffusivity (MD) were quantified on different white and gray matter regions. Patients exhibited significantly increased Gln/Cr and Glx/Cr ratios compared to controls. Significantly decreased Cho/Cr was observed in deceased patients compared to controls. In patients, significantly decreased MD and FA values were observed in different brain regions compared to controls. In follow-up study, MD and FA values showed an insignificant increase.

15:00 3268. Longitudinal Diffusion Tensor MR Imaging Study of Radiation Induced White Matter Damage in a Rat Model Silun Wang1, Chung Nga Tam1, Ed X Wu1, Ho-Fai Lau1, Deqiang Qiu1, Lucullus H.T. Leung2, Pek-Lan Khong1 1The University of Hong Kong, Hong Kong, Hong Kong; 2Princess Margaret Hospital, Hong Kong, Hong Kong

We evaluate the longitudinal changes in DTI indices and its histological correlates in a radiation induced white matter (WM) injury rat model.The results show that radiation induced WM injury is reflected by significant reduction in FA and ¦Ë// as early as 4 weeks after injury, prior to T2WI signal changes. These changes correlate with astrocytic hypertrophy, suggesting that the relative abundance of astrocytes influence ¦Ë// in the early changes of radiation induced WM injury, and this occurs before necrosis, axonal loss and demyelination. Therefore, FA and ¦Ë// may be biomarkers for early detection of radiation induced WM injury.

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15:30 3269. Alteration in DTI Metrics and Volume of the Mamillary Body in Patients with Hepatic Encephalopathy Secondary to Non-Alcoholic Cirrhosis Rakesh K. Gupta1, Vivek A. Saraswat1, Pooja Upreti1, Rajendra Singh1, Jitesh K. Singh2, Richa Trivedi1, Sunil Kumar1, Ram KS Rathore2 1Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India; 2Indian Institute of Technology, Kanpur, India

Diffusion tensor imaging (DTI) was performed in 28 patients with end stage chronic liver disease and 25 age/sex matched controls. Mamillary body volume and DTI metrics in mamillary body were quantified by using in-house JAVA based software. Significantly decreased fractional anisotropy (FA) and linear anisotropy (CL) with increased spherical isotropy (CS) and mean diffusivity (MD) values were observed in patients compared to controls. No change in volume of mamillary body was observed between patients and controls. Absence of the changes in the volume of the mamillary bodies compared to controls suggests that DTI is more sensitive for the early detection of changes due to thiamine deficiency in these patients.

Diffusion Modelling Hall D Monday 14:00-16:00

14:00 3270. Diffusion Tensor Imaging in Glioblastoma Multiforme and Brain Metastases: The Role of P, Q, L and FA Chris Steward1, 2, Wayland Wang1, Patricia Desmond1, 2 1University of Melbourne, Melbourne, Australia; 2Royal Melbourne Hospital, Melbourne, Australia

Micro-invasive tumour cells, which are not detected on conventional imaging, contribute to poor prognoses for patients diagnosed with glioblastoma multiforme (GBM; WHO grade IV). Diffusion tensor imaging (DTI) shows promise in being able to detect this infiltration. This study aims to detect a difference in diffusion properties between GBM (infiltrative) and brain metastases (non-infiltrative). In particular, to compare the diffusion tensor metrics p, q, L, and FA from tumoural and peritumoural regions of glioblastoma multiforme and metastatic brain tumours 2/ To determine whether these parameters can be correlated with the type of tumour and the extent of infiltration into surrounding white matter 3/ To determine whether these parameters, and more broadly DTI, has a significant clinical meaning, and thus whether it should be included in imaging protocols for suspected brain tumour and for treatment planning.

14:30 3271. About "Axial" and "Radial" Diffusivities Claudia Angela Michela Wheeler-Kingshott1, Mara Cercignani1, 2 1Institute of Neurology, UCL, London, UK; 2Fondazione Santa Lucia, Rome, Italy

DTI allows the quantitative assessment of diffusion anisotropy in tissues. It is well known that the DT can be diagonalised, determining three eigenvectors and their eigenvalues. We have questioned the rationale that underpins the relationship between axial and radial diffusivities and specific biophysical substrates, based on the already established knowledge of the uncertainty of the eigenvectors/values measures. Using two healthy-controls and two people-with-MS we have demonstrated what kind of serious interpretation errors can arise when comparing one or more eigenvalues of the DT across datasets. Our results are strongly supporting the not-yet-recognised need for including the eigenvectors when comparing eigenvalues.

15:00 3272. Quantitative Relations of Axial and Radial Diffusivities to Anisotropy Indices in Diffusion Tensor Imaging Ling-chih Lin1, Jianhui Zhong1 1University of Rochester, Rochester, New York, USA

Sensitivities of radial and axial diffusivities with respect to other diffusion anisotropy indices (DAIs) were evaluated numerically. Monte Carlo Simulation was performed to evaluate the effect of the signal to noise ratio (SNR) to their accuracy. Correlations between the axial and radial diffusivities and other DAIs were examined to facilitate the optimal selection of diffusion anisotropy measurement parameters.

15:30 3273. Three Novel Methods for Studying Complicated Diffusion Behavior Using Simple Capillary Structures Nathan Yanasak1, Qun Zhao2, Tom C.-C. Hu1, Jerry Allison1 1Medical College of Georgia, Augusta, USA; 2University of Georgia, Athens, USA

Although DTI has shown great clinical potential for studying a variety of neurological conditions, procedures and equipment for quality assurance of clinical data are still in development. In particular, noise can bias anisotropy measurements, yet phantom designs are generally limited to simple anisotropic structures less characteristic of tissue. This study introduces three new techniques to assist in the characterization of data quality for complicated tissue-like structures. Images acting as input are acquired using a phantom with capillary structures. In this manner, data quality from images of complex structures can be inferred from a QA phantom.

14:00 3274. Constrained Single Step Diffusion Tensor Reconstruction Using Cholesky Decomposition Murat Aksoy1, Roland Bammer1 1Stanford University, Stanford, California , USA

In DTI, the diffusion model requires the tensor to be positive definite. Several methods have been proposed to ensure positive definiteness, such as replacing negative eigenvalues or constraining tensors to be positive definite using matrix decomposition. In this study, we propose a single step non-linear tensor estimation scheme that utilizes Cholesky decomposition to guarantee the positive definiteness of the reconstructed diffusion tensors. The presented algorithm estimates the diffusion tensor directly from the unity of all k-space data in a non-linear fashion and it is especially effective in correcting gross patient motion in the case of multi-shot DTI scans.

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14:30 3275. Using Fractional Anisotropy Neighbourhood Information in a Bayesian Based Regularisation Technique for DTI Marta Morgado Correia1, Tim Hosey1, Sally G. Harding1, Thomas Adrian Carpenter1, Guy B. Williams1 1University of Cambridge, Cambridge, UK

A new regularisation method for DT-MRI, which is capable of improving the confidence in the FA maps obtained from diffusion weighted MRI datasets, is introduced. The idea behind this prior is that the variation of FA along a fibre tract should be smooth, and therefore if there is a tract connecting two neighbour voxels, the FA variation between these two voxels should be small. The regularisation is applied to the priors of a MCMC model rather than the data itself, meaning that the fit is biased towards spatially consistent solutions but this only when supported by the data.

15:00 3276. Modelling Diffusion-Weighted Steady-State Free Precession in Terms of the Reciprocal Spatial Wave Vector and Non-Gaussian Diffusion Probability Density Functions Jennifer Andrea McNab1, Karla L. Miller1 1University of Oxford, Oxford, UK

Diffusion-weighted steady-state free precession (DW-SSFP) accumulates signal from multiple echoes over several TRs yielding a strong sensitivity to diffusion with short gradient durations and imaging times. DW-SSFP is thus of great interest as a potential method for high angular and spatial resolution diffusion imaging. The DW-SSFP signal is well characterized for isotropic, Gaussian diffusion, however, it is unclear how the multi-echo signal propagates for inhomogenous media. In this study, the DW-SSFP signal equation is presented for the first time in terms of the reciprocal spatial wave vector (q) and an arbitrary diffusion probability density function pdf (P(r, δ)).

15:30 3277. Toroid-Based Characterization of Cardiac DT-MRI Choukri Mekkaoui1, Marcel P. Jackowski2, Albert J. Sinusas1 1Yale University School of Medicine, New Haven, USA; 2Institute of Mathematics and Statistics, São Paulo, Brazil

The aim of the present study is to introduce a novel toroid-based representation of diffusion tensor fields to improve myofiber visualization and macrostructure analysis. A new diffusivity index, the toroidal volume (TV), and a new coefficient of anisotropy, the toroidal volume ratio (TVR), are defined. Toroidal glyph renderings from a normal canine heart were compared to ellipsoidal and superquadric glyph fields. TV and {1-TVR} maps were calculated for a DT-MRI dataset of an infarcted canine heart and compared to contemporary indices. Results demonstrate that the proposed methodology improves diffusion tensor visualization and may complement existing diffusion indices.

MRI & MRS of Cerebral Ischemia Hall D Tuesday 13:30-15:30

13:30 3278. Susceptibility-Weighted Imaging in Hyperacute Cerebral Ischemia Masahiro Ida1, Kennichi Motoyoshi1, Hiroyuki Fukuyama1, Hisashi Yoshizawa1, Naoya Yorozu1, Keiko Hino1 1Tokyo Metroplolitan Ebara Hospital, Oota-ku, Japan

Increased vessel contrast (IVC) suggests a relative increase of intravenous paramagnetic deoxyHb and a relative reduction of oxyHb due to the impaired oxygenation (misery perfusion state). SWI can detect not only an area of perfusion impairment but also occluded artery. SWI provides important adjunct information for HIS. IVC is a useful finding to assess acute misery perfusion state without contrast media and a reliable indicator for determining whether a patient should undergo Gd-perfusion study.

14:00 3279. Feasibility of Longitudinal Study Using Arterial Spin-Labeling Perfusion MRI in Pediatric Arterial Ischemic Stroke Juan Chen1, 2, Daniel J. Licht3, Yong Fan1, Sabrina E. Smith3, Shannon C. Agner3, Stefanie Mason3, Robert A. Zimmerman3, Rebecca N. Ichord3, Jiongjiong Wang1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA; 2Beijing Hospital, Beijing, People's Republic of China; 3the Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA

This is a longitudinal study of cerebral perfusion and lesion volume changes in three pediatric patients with acute stroke. The aim of the study was to demonstrate feasibility of pulsed arterial spin-label (PASL) perfusion MRI to follow perfusion deficits and their relation with changes in lesion volume over time. Ischemic lesions showed a trend of decreasing volume over time accompanied by decreasing perfusion within the shrinking lesion. Voxel-based scatterplot analysis of the region of diffusion restriction indicate that tissue within the lesion has relatively higher perfusion and may represent viable and potentially salvageable tissue.

14:30 3280. Altered Regional CO2 Vasoreactivity in Patients with Ischemic Stroke Using CASL MRI Peng Zhao1, David Alsop2, Magdy Selim3, Amir Abduljalil4, Peter Novak5, Lewis Lipsitz1, Kun Hu1, Sarah LaRose1, Vera Novak1 1Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA; 2Radiology, Beth Israel Deaconess Medical Center,, Boston, Massachusetts, USA; 3Neurology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA; 4Radiology, Ohio State University, Columbus, Ohio, USA; 5Medicine, University of Massachusetts, Boston, Massachusetts, USA

This study investigated the regional differences in CO2 vasoreactivity (CO2VR) after stroke and their relationship to clinical outcomes. 27 subjects with chronic large vessel infarcts in the middle cerebral artery (MCA) territory were compared with 43 controls by using continuous arterial spin labeling (CASL) perfusion MRI. Impairment of CO2VR after stroke was observed which extended into additional brain regions and vascular territories not within the ischemic region.

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15:00 3281. Quantitative Assessment of Brain Mass Effect Using Mid-Brain Surface in Stroke Patients Yasheng Chen1, Chung-Yi Yang2, Cheng-Hong Toh1, Hongyu An1, Allyson Zazulia3, Thomas Vedeen3, Michael Diringer3, William Powers1, Weili Lin1 1The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; 2National Taiwan University Hospital, Taiwan; 3Washington University in St. Louis, St. Louis, Missouri, USA

The current approach for quantitatively measuring brain mass effect employs manual measurements of the 2D displacement between the altered brain midline and the putative normal midline in specific anatomical locations including the pineal body, septum pellucidum, and third ventricle. One major limitation associated with this approach is the inability to assess the true 3D extent of brain mass effect. An automated approach reconstructing the mid-brain surface is developed, allowing a direct assessment of mass effects through measuring the volume enclosed by the deformed and the estimated of un-deformed brain mid-surface.

13:30 3282. White Matter Integrity But Not BOLD Response Predicts Upper Limb Motor Function in Patients After Stroke mingguo qiu1, Justin Rajendra2, Warren Darling3, Robert Morecraft4, Chunchun Ni2, Andrew J. Butler2 1Southwest hospital of Third military medical university, chongqing, People's Republic of China; 2Emory University, School of Medicine, Atlanta, Georgia, USA; 3The University of Iowa, Iowa City, Iowa, USA; 4University of South Dakota, Vermillion, South Dakota, USA

The aim was to establish the relationship between upper-extremity motor functional outcomes with the asymmetry of fractional anisotropy (FA) from DTI and with the laterality index (LI) derived from functional MRI. Seventeen patients after stroke were enrolled and measured the motor function by Wolf Motor Function Test (WMFT) and Fugl-Meyer (FM) assessment. The data showed a significant relationship between FA asymmetry of PLIC with FM and WMFT asymmetry, white matter integrity can strongly predict current motor function. However, LI can’t predict the current clinical outcomes; no relationship was found between the LI with the FA asymmetry and clinical motor outcomes.

14:00 3283. Assessing the Evolution of Sodium MRI with Time After Onset in Human Stroke Robert Wayne Stobbe1, Muhammad Shazam Hussain2, Yusuf A. Bhagat2, Ken S. Butcher1, Derek J. Emery1, N Rizvi1, Perkash Maheshwari1, Ashfaq Schuaib1, Christian Beaulieu1 1University of Alberta, Edmonton, Canada; 2University of Alberta, Edmonton , Canada

Sodium MRI signal intensity within the ischemic lesion is shown to evolve over time after symptom onset in human acute stroke. Given significant early changes it may be possible to estimate time of onset in patients when this important factor is unknown, and possibly increase options for treatment.

14:30 3284. Elevated Choline/Creatine Ratio in Central Nervous System Arterial Infarction: Frequency, Timing, Extent and the Effect of Echo Time Metin Bora Vardar1, Gur Akansel, 12, Nagihan Inan1, 1, Hasan Tahsin Sarisoy1, 1, Arzu Serpil Arslan1, 1, Ercument Ciftci1, 1, Ali Demirci1, 1 1; 2Kocaeli University School of Medicine, Kocaeli, Turkey

Although the MRI diagnosis of cerebral infarction is usually straightforward with the use of diffusion-weighted imaging, infarcts first seen in the late subacute stage remain a challenge to differentiate from neoplasm. Since cytotoxic edema subsides in the late subacute period, abnormalities of apparent diffusion coefficient due to restricted water diffusion are of limited help. Hemorrhagic transformation and abnormal contrast enhancement due to blood brain barrier breakdown may further complicate the picture.A common clinical indication for proton MRS is the differentiation of neoplastic from non-neoplastic central nervous system lesions. MRS is frequently performed to differentiate subacute infarcts from neoplasm. However, elevated choline content that may be encountered in subacute infarcts may impede the contribution of MRS in this differentiation.In this study, we evaluated choline/Creatine ratios in cases of acute, subacute and chronic central nervous system infarction to detect the frequency, timing and the extent of the elevation in choline/Creatine ratio. Our aim was to determine if the MRS pattern in subacute infarction was sufficiently different from that which characterizes a neoplasm.

15:00 3285. fMRI of Rehabilitation in Chronic Stroke Using MR-Compatible Robots Dionyssios Mintzopoulos1, 2, Loukas G. Astrakas1, Walter J. Koroshetz1, Michael A. Moskowitz1, Bruce R. Rosen1, A Aria Tzika1 1Massachusetts General Hospital, Boston, Massachusetts, USA

Using a hand motor task, we investigated brain activation after chronic stroke by combining fMRI at 3T with a novel MR-compatible hand-induced, robotic device (MR_CHIROD). Patients trained at home using a gel ball; serial neuroimaging was performed before, during, upon completion of training, and after a non-training period, to assess permanence of effects. Training significantly increased the number of activated voxels in the cortex as a function of effort level, suggesting functional cortical plasticity in chronic stroke. The result¢s persistence indicates permanence of rehabilitation, which is remarkable given that training is generally effective during a narrow window after stroke.

13:30 3286. MRI Metrics Detected Axonal Outgrowth and Plasticity in Rat Brain After Embolic Stroke Guangliang Ding1, Quan Jiang1, Lian Li1, Li Zhang1, Zhanggang Zhang1, Karyn A. Ledbetter1, 2, Swayamprava Panda1, Siamak P.N. Davarani1, 3, James R. Ewing1, Michael Chopp1, 4 1Henry Ford Health System, Detroit, USA; 2Michigan State University, East Lansing, USA; 3University of Michigan, Ann Arbor, USA; 4Oakland University, Rochester, USA

Both angiogenesis and axonal outgrowth were detected as early as 1 week after stroke in sildenafil treated rats. Angiogenesis and axonal plasticity were co-localized with each other, measured histologically at 6 weeks and dynamically in vivo by MRI up to 6 weeks after stroke. This indicates that sildenafil treatment of stroke may simultaneously promote angiogenesis and axonal plasticity after embolism in rats. Local CBF in the co-localized area was increased after angiogenesis. Both elevated CBF and re-organized white matter in ischemic areas may contribute to recovery of neuronal function after stroke in rats.

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14:00 3287. Noninvasive Detection of White Matter Reorganization Enhanced by Erythropoietin Treatment in a Rat Model of Focal Ischemia Using MRI Lian Li1, Quan Jiang1, Guangliang Ding1, Li Zhang1, Zhenggang Zhang1, James R. Ewing1, Michael Chopp1, 2 1Henry Ford Health System, Detroit, Michigan, USA; 2Oakland University, Rochester, Michigan, USA

The objective of the present study was to noninvasively identify and monitor the progress of white matter reorganization within 6 weeks after the onset of stroke and correlate this structural change with improved neurological function using MRI. Our data in rats indicate that FA is a sensitive measure of white matter changes after stroke and provides an important noninvasive means for real-time evaluation of treatment efficacy and functional outcome. Treatment with EPO significantly enhances white matter reorganization, which correlates with local restoration of CBF and recovery of neurological function

14:30 3288. Increased Connectivity of the Contralesional Sensorimotor Cortex at a Chronic Stage After Stroke as Studied by Manganese-Enhanced MRI in Rats Maurits Pieter Adriaan van Meer1, 2, Wim M. Otte1, Kajo van der Marel1, J. W. Berkelbach van der Sprenkel1, Rick M. Dijkhuizen1 1University Medical Center Utrecht, Utrecht, Netherlands

Manganese-enhanced MRI was applied after injection of MnCl2 in the contralesional primary sensorimotor cortex of rats at 10 weeks after unilateral stroke. Subsequent ROI analysis of the time-course of manganese-induced R1 increases revealed increased tracer uptake and distribution in contralesional subcortical ROIs and ipsilesional cortical ROIs as compared to controls. Our data support the concept of structural remodeling of the contralesional cortex and increased connectivity with other sensorimotor network areas, which may significantly contribute to post-stroke functional recovery.

15:00 3289. Magnetic Resonance Imaging of Delayed Administration of Manganese After Transient Focal Cerebral Ischemia Kevin C. Chan1, 2, Victor K. Hung1, Matthew M. Cheung1, Ke Xia Cai1, Dave K. Cheung1, Chi-tat Chiu1, Po-mak Chan1, Xiao-guang Zhao1, Sookja K. Chung1, Ed Xuekui Wu1 1The University of Hong Kong, Pokfulam, Hong Kong

This study aims to employ in vivo magnetic resonance imaging to understand longitudinally the effect of systemic MnCl2 administration on delayed secondary changes after transient middle cerebral artery occlusion (MCAO). Results showed a significant increase in T1 signal intensities in the perilesional rim compared to the ischemic core in dorsolateral striatum 24 hours after Mn2+ injection, whereas colocalization was found between manganese-enhanced MRI pattern and immunostaining for GFAP, MnSOD and GS, likely due to their Mn-dependent upregulation against oxidative stress and glutamate excitotoxicity. Total ipsilateral infarcted volumes in the posterior parts of the brain had also significantly reduced after Mn2+ injection, illustrating the potential neuroprotective effects of manganese upon delayed postischemic administration.

13:30 3290. Delayed T2 Changes Following Cerebral Ischaemia and Cell Transplantation with Ferumoxide-Labelled Neural Stem Cells Rachael Dobson1, 2, Patrizia Ferretti1, Mark F. Lythgoe1 1University College London, London, UK

Transplantation of stem cells following cerebral ischaemia has been shown to improve functional outcome. MRI contrast agents have been used to track the migration of transplanted cells towards lesions. The protamine sulphate-ferumoxide complex – FePro –enhances cell labelling. In this study, migration of neural stem cells, labelled with FePro, was monitored using MRI in a model of cerebral ischaemia. Little migration was observed. Hypointense regions on T2-weighted images developed within lesions, and iron was detected histologically, in cell treatment and control groups. These results highlight issues for cell tracking studies using MRI contrast agents in animal models of disease.

14:00 3291. MRI Evaluation of the Effect of a COX-2 Inhibitor on BBB Permeability in a Rat Stroke Model Saeid Taheri1, Eduardo Candellario-Jalil1, Eduardo Estrada1, Gary Rosenberg1, Rohit Sood1 1University of New Mexico, Albuquerque, New Mexico, USA

Recent research has demonstrated an increase in expression of cyclooxygenase (COX-2) mRNA within neurons and vascular cells and it has been postulated that COX-2 plays an important role in secondary events that amplify brain damage post-ischemia. There is additional evidence that COX-2 is involved in the increase in BBB permeability. The purpose of this study was to use MRI based BBB permeability estimation technique to evaluate the effects of nimesulide, a non-steroidal anti inflammatory drug on BBB permeability in a rat model with focal cerebral ischemia at 48h post MCAO. Initial results suggest that nimesulide is effective in reducing BBB damage 48h post ischemia and would be potential candidate for therapeutically reducing late phase brain damage post ischemic stroke.

14:30 3292. in Vivo 1H/13C MRSI of Changes in Neurotransmitter Metabolism in Rats Recovering from Stroke Pieter van Eijsden1, Jet P. van der Zijden2, Robin A. de Graaf3, Rick M. Dijkhuizen2 1University Medical Center, Utrecht, Netherlands; 2University Medical Center Utrecht, Netherlands; 3Yale University, New Haven, USA

Post-stroke functional recovery has been associated with brain plasticity in the lesion borderzone, but its metabolic basis is unknown. To characterize alterations in oxidative glycolysis and neurotransmitter metabolism, we applied in vivo dynamic 1H/13C MR spectroscopic imaging after infusion of 13C-labeled glucose in rats after transient stroke. Semi-acutely, reductions in NAA levels and Glu turnover implied severe neuronal dysfunction in the lesion borderzone. At 3 weeks post-stroke, NAA levels and Glu turnover had normalized, suggestive of neuronal recovery. Our findings show that early metabolic impairment in the morphologically intact lesion borderzone recovers over time, contributing to post-stroke functional improvement.

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15:00 3293. Magnetic Resonance Spectroscopy and Imaging at 9.4T in P4 Rat Pup Brain Following Cerebral Hypoxia-Ischemia Yohan van de Looij1, 2, Alexandra Chatagner2, Nicolas Kunz1, Petra S. Hüppi2, Stéphane V. Sizonenko2, Rolf Gruetter1, 3 1Laboratory for Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; 2Division of Child Growth & Development, Department of Pediatrics, University of Geneva, Geneva, Switzerland; 3Departments of Radiology, University of Geneva and University of Lausanne, Geneva and Lausanne, Switzerland

To define the nature of diffuse injuries of the very preterm infant, we use the model of neonatal hypoxic-ischemic injury in the 3-day old (P3) rat pup and we investigate acute and long term brain alterations using high-field MRI and MRS. At P4, the ispilateral cortex indicated significant modifications for several metabolites reflecting an energetic and functional slowing-down of the injured cortex. At P11 no significant differences between both cortices were found, ascribed to a low number of animals and possibly to intervening partial tissue repair. Relation between metabolic changes and severity of the injury requires further investigations.

13:30 3294. In Vivo Early MRI and MRS at 9.4T of Combined Hypoxia-Hypotension and Traumatic Brain Injury in the Rat Bich-Thuy Doan1, 2, Fanny Noury3, Thomas Geeraerts4, Arnaud Friggeri5, Philippe Meric1, Sandra Meme3, Bernard Vigue4, Jean-Claude BeloeilL3 1CNRS, Gif sur Yvette, France; 2Orléans, France; 3CNRS, Orléans, France; 4AP-HP, University of Paris Sud, Kremlin Bicetre, France; 5AP-HP, France

Following traumatic brain injury (TBI), hypoxia and hypotension are frequent and damaging secondary insults.The aim of this work is to characterize the traumatic injury by MRI (T2, diffusion tensor, angiography) and MRS experiments in vivo on rat brain. The final aim is to understand the role of secondary insults like hypoxia and hypotension (HH) in the development of post-traumatic brain oedema.Using an animal model of diffuse TBI complicated by HH, we focused on post-traumatic brain oedema development using MRI combined with MRS, as well as consequences of post-traumatic perturbations on brain energy metabolism using cerebral microdialysis.

14:00 3295. Single Voxel MR Spectroscopy with Echo Times Below 2 Ms at 16.4 T in the Rat Brain: First in Vivo Results David Zsolt Balla1, Sung-Tak Hong1, Gunamony Shajan1, Rolf Pohmann1, Kamil Ugurbil1, 2 1Max Planck Intitute for Biological Cybernetics, Tuebingen, Germany; 2Center for Magnetic Resonance Research, Minneapolis, USA

Single voxel MRS techniques employ at least three RF-pulses to generate an echo in the selected volume and gradients to dephase magnetization in the outer region. During the time between excitation and acquisition, relaxation effects and phase modulation by J-couplings affect the NMR signal. The STEAM sequence can be applied with very short echo times to obtain localized spectra containing fast decaying components and peaks from all detectable coupled resonances. We show in vivo spectra from the rat brain acquired at 16.4 T with localized spectroscopy using echo times below 2 ms and compare them to results from the literature.

14:30 3296. Time Courses and Correlation of Diffusion-Weighted MR and CT Imaging in Acute MCA Ischemia with Rat Model Hyung Suk Seo1, Dong Gyu Na2 1dongguk university international hospital, goyangsi, Republic of Korea; 2Seoul National University College of Medicine, Seoul, Republic of Korea

Unlike ADC value, DWI signal in acute cerebral ischemia increases with time and correlates with CT density, which decrease with time. It means that the signal change of DWI after 3 hours is influenced by net water uptake in ischemic edema rather than by restricted water diffusion and DWI will be used as the predictor of ischemic injury severity like CT.

15:00 3297. Brain Tissue Ischemic Transitions During Permanent Middle Cerebral Artery Occlusion (PMCAO) in Rats Lesley May Foley1, T. Kevin Hitchens1, Brent Barbe2, Joyce A. Horner1, Edwin M. Nemoto2 1Carnegie Mellon University, Pittsburgh, Pennsylvania, USA; 2University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA

The identification of the ischemic penumbra in acute stroke is important for therapeutic intervention. Whereas qualitative MRI perfusion and diffusion mismatch does not accurately identify the ischemic penumbra, it may be identified by quantitative measurements using ASL for perfusion and ADC with appropriate thresholds. Using these methods, we were able to describe brain tissue ischemic transitions in the first four hours and up to three weeks after pMCAO.

13:30 3298. Mild Hypoxic-Ischemic Brain Injury in Neonatal Rats Using Diffusion Tensor MR Imaging: A Longitudinal Study Silun Wang1, Ed X Wu1, Chung Nga Tam1, Edward S Hui1, Pek-Lan Khong1 1The University of Hong Kong, Hong Kong, Hong Kong

We evaluate the longitudinal changes (D1 to D90 post-injury) in the white matter (WM) of a mild hypoxic-ischemic (HI) rat brain injury model using DTI and correlate the findings with histology. Significantly elevated ¦Ë¡Í with no change in ¦Ë// in the ipsilateral WM was found, suggesting reduced myelination in the ipsilateral WM as a consequence of mild HI injury and this was confirmed by Luxol fast blue stain. Longitudinal changes of DTI indices on the ipsilateral WM parallel changes of normal development in the contralateral WM suggesting continual maturation processes after HI injury.

14:00 3299. Comparison of Two Methods of Assessment of Perfusion-Diffusion Mismatch in a Rodent Model of Ischemic Stroke Feng Chen1, Yicheng Ni1, Guy Marchal, Jie Yu1, Yasohiro Suzuki, Nobuo Nagai 1Catholic University of Leuven, Leuven, Belgium

The present study demonstrated that the PWI-ADC pattern evolves from a mismatch pattern through a match pattern to a reversed mismatch pattern after stroke onset. The PWI-ADC mismatch pattern was observed up to 72h after MCA occlusion in this animal model. There are linear correlations of volume and mismatch occurrence between e(early)PWI-i(instant)ADC and iPWI-iADC models. The PWI-ADC pattern could be defined either with ePWI or iPWI before 24h after stroke onset. The iPWI appeared more adequate compared to ePWI to define the PWI-ADC pattern at 72h.

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Diffusion: Artifacts, Phantoms, QA, Reproducibility Hall D Tuesday 13:30-15:30

13:30 3300. Quality Assessment Through Analysis of REsiduals of Diffusion Image Fitting Alexander Leemans1, Christopher John Evans1, 2, Derek K. Jones1 1School of Psychology, Cardiff University, Cardiff, UK; 2GE Healthcare, Chalfont St. Giles, UK

In order to obtain reliable quantitative results, it is important to assess the quality of DTI data with respect to subject motion, distortions, signal dropouts, etc. prior to performing further analyses. In this context, we developed a comprehensive DTI quality assessment (QA) tool that provides a ‘direct feel’ and ‘global overview’ of the data in an automatic way. We show how this exploratory tool can be used to efficiently identify subject motion, signal dropouts, and image distortions, without the need to perform QA on all the individual diffusion weigthed MR images.

14:00 3301. Analysis of Noise Corrected Diffusion Decay of Human Brain Elena Olariu1, Arturo Cardenas-Blanco2, Ian Cameron, 12 1Carleton University, Ottawa, Canada; 2Ottawa Health Research Institute, Ottawa, Canada

Several studies have shown that, there is a significant deviation of the MR signal, for both gray matter (GM) and white matter (WM), from the mono-exponential model; however, there is no clear consensus as to whether the diffusion decay has one or more exponential contributions. Our purpose was to carefully characterize the diffusion attenuation in WM and GM over an extended range of b-values, and to use a post-processing scheme to reduce the noise bias to see if a second exponential component could be observed.

14:30 3302. Quality Assurance of MR Scanner on Diffusion Tensor Imaging Zili Chu1, 2, Jonathan Chia3, Zhiyue J. Wang1, 2 1Baylor College of Medicine, Houston, Texas, USA; 2Texas Children's Hospital, Houston, Texas, USA; 3Philips Medical Systems, Cleveland, Ohio, USA

Diffusion Tensor Imaging (DTI) is prone to artifacts associated with EPI and strong diffusion encoding gradients. Therefore, periodically assessing the performance of the scanner on the DTI sequence is essential to ensure good image quality. Here, we propose the use of a glycerin-gel spherical phantom constructed to be similar to the human brain in terms of apparent diffusion coefficient (ADC) and T2.The temperature of the phantom is controlled during the QA data acquisition. The calculated ADC, FA, image center displacement and distortion on the DTI data of the phantom can be analyzed to serve as indicators of the scanner performance.

15:00 3303. A Frame-Work for DTI Quantitation, Visualization & Analysis Ankur Purwar1, RKS Rathore1, RK Gupta2, D Rathore1, G Bayu1, MK Sarma1, Anup Singh1, JK Singh1, S Verma1 1IIT Kanpur, Kanpur, India; 2SGPGIMS Lucknow, Lucknow, India

DTI is an important tool to study brain white matter anatomy/abnormalities. The data processing and analysis in DTI is quite elaborate and so far no commercial and easily extendable/modifiable tool for the same is available. In view of the same, we present a tool frame-work focusing on DTI technology combining all of the above needs. It has 4 mutually independent modules namely DTI Processing Module, DTI Visualization Module, ROI Analysis Module and Tracking and Fiber data Visualization Module. The Tool can read various data formats from different scanners including the raw binary format. An automatic de-scalping procedure is also implemented.

13:30 3304. Validation of Diffusion Tensor Imaging and Tractography of the Human Peripheral Nerve Using Small-Diameter Ex Vivo Phantoms Akira Kunimatsu1, 2, Masayuki Yamaguchi2, Yoshikazu Okamoto1, Izumi Anno1, Hirofumi Fujii2, Atsushi Nozaki3, Hiroyuki Kabasawa3, Manabu Minami1 1Institute of Clinical Medicine, University of Tsukuba, Tsukuba, Japan; 2Research Center for Innovative Oncology, National Cancer Center Hospital East, Kashiwa, Japan; 3GE Yokogawa Medical Systems, Hino, Japan

We aimed to develop small-diameter, flexible, ex-vivo phantoms for validation of diffusion tensor (DT) imaging and tractography of the human peripheral nerve on a clinical MR imager with standard coils. Our results suggest that DT imaging and tractography are feasible even with a 4-mm-diameter phantom on a clinical imager without any dedicated or special coil. Four or more numbers of excitations and 15 or more motion probing gradient directions may provide robust results of fractional anisotropy measurement and fiber-tracking of the human peripheral nerve.

14:00 3305. Impact of Resolution on Tissue-Specific DTI Parameters at 3T: Roles of Partial Volume, SNR and Tissue Structure Xiaogeng Feng1, Dae-Shik Kim1, Itamar Ronen1 1Boston University School of Medicine, Boston, Massachusetts, USA

With the proliferation of high field MRI scanners (B0 ≥ 3T), it is now possible to acquire DTI data of the human brain at a reasonably high spatial resolution. Increased resolution, however, has implications on the assessment of DTI parameters such as ADC and FA that are different for white matter and cortical gray matter. This work aims to evaluate the tissue-specific effects of increased resolution in carefully segmented DTI data sets and explain the interplay between SNR, partial volume effects and macroscopic characteristics (e.g. curvature effects), which is shown to be significantly different in brain gray and white matter.

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14:30 3306. Simple, Reliable and Precise Quantitative Quality Assurance of In-Vivo Brain ADC Nicholas G. Dowell1, 2, Paul S. Tofts1, 2 1University of Sussex, Falmer, UK; 2UCL, London, UK

Measuring diffusion with MRI is a useful and popular method of studying many pathological conditions in vivo. The apparent diffusion coefficient (ADC) is commonly used to quantify the extent of diffusion; however, there is a need for reliable quantitative quality assurance of the technique. We use decane, dodecane and tetradecane as test liquids that exhibit similar ADC values to those observed in the human brain in vivo. We demonstrate that serial measurements of ADC can be referenced to a standard temperature to avoid variation due to temperature fluctuations. The materials used here are stable, readily available and safe to handle.

15:00 3307. Looking for the Optimal DTI Acquisition Scheme Given a Maximum Scan Time: Are More B-Values a Waste of Time? Marta Morgado Correia1, Thomas Adrian Carpenter1, Guy B. Williams1 1University of Cambridge, Cambridge, UK

By using simulated data, this study has shown that the use of more than 1 b-value in DTI acquisition schemes can minimize the systematic bias of ADC and FA estimates due to the Rician noise distribution, and also produce results closer to the simulates ones and less variable due to noise and fibre rotation. In addition, the use of more than 1 b-value accounts better for the great diversity of diffusivities we find in the brain. For tractography studies, however, we should use as many sampling directions as allowed by scan time limitations.

Fiber Tracking & Connectivity Mapping Hall D Wednesday 13:30-15:30

13:30 3308. In Vivo Localisation of Fibre Tracts: Optimisation of Fibre Tracking to Reduce Voxel Misclassification J-Donald Tournier1, 2, Fernando Calamante1, 2, Alan Connelly1, 2 1Brain Research Institute, Melbourne, Australia; 2University of Melbourne, Melbourne, Australia

Diffusion tractography is increasingly being used in clinical and neuroscientific applications. However, reliable tracking requires methods to resolve crossing fibres that have yet to be optimised. Here, we investigate the effects of acquisition and reconstruction parameters on the reconstructed fibre tracts estimated using sophisticated methods, by quantifying the volume of white matter misclassified as belonging or not to the tract. We show that misclassified volume is consistently reduced by using more diffusion-weighted directions and higher spherical harmonic orders. Measures of false tract and omitted tract volume also provide a means of tailoring the acquisition and reconstruction to the application.

14:00 3309. A New Fiber Tract Color-Encoding Scheme Based on Diffusion Tensor Model Residuals Alexander Leemans1, Derek K. Jones1 1School of Psychology, Cardiff University, Cardiff, UK

Due to the multi-component nature of DTI data, distinguishing between real and artifactual observations is often non-trivial. To bridge this gap between the acquired images and the understanding of the underlying WM microstructure, specialized visualization methods have been developed that display various WM properties along the fiber tracts. However, none of these visualization approaches reflects the acquired data quality (artifacts) or Goodness-of-Fit (GoF) to the model, which is crucial in interpreting analysis results. In this context, we developed a new color-encoding scheme for visualizing fiber tracts, based on the analysis of tensor model residuals, which allows the investigation of data quality and GoF.

14:30 3310. Combination of Distance Measures for Optimal Fiber Clustering in Diffusion Tensor Imaging Daniel Güllmar1, 2, Jana Langner1, Jens Haueisen2, Jürgen R. Reichenbach1 1University Hospital Jena, Jena, Germany; 2TU Ilmenau, Illmenau, Germany

From Diffusion Tensor data of the human brain one can derive beautiful fiber tracts employing deterministic algorithms in order to mimic the neuronal pathways. However it is hard to distinguish between the different tracts, although the tracts itself are easy to recognize by visual inspection. Several studies showed that one can perform clustering based on distance measures between the fiber path ways. Thus it is possible to objectively group the paths in order to distinguish between at least the major tracts. The aim of the presented study is to combine different distance measures to handle deficiencies of single distance measures.

15:00 3311. Tracking of CE-MR-Angiography Data Using Established Approaches in DTI Daniel Güllmar1, 2, Andreas Deistung1, Stefan Richter1, Jens Haueisen2, Jürgen R. Reichenbach1 1University Hospital Jena, Jena, Germany; 2TU Ilmenau, Ilmenau, Germany

We propose a method to generate tractograms from CE-MR-Angiography data using existing tools designed to work on diffusion tensor data. The pseudo DT data are generated by converting the Hessian matrix derived from a multi-scale approach in order to obtain a highly anisotropic tensor representation along the vascular system. The results derived from a high resolution 3D MR angiographic extremity data set demonstrate that it is possible to reconstruct the vascular system with diffusion tensor fiber tracking tools. Only deterministic tracking was applied so far which leads to some extent to fragmentary reconstruction, which may be overcome by probabilistic tracking.

13:30 3312. Local DTI Connectivity Estimation Using Bayesian Probability Theory Joshua S. Shimony1, Adrian A. Epstein1, G Larry Bretthorst1 1Washington University School of Medicine, St. Louis, Missouri, USA

The diffusion tensor model has been used to analyze magnetic resonance diffusion data and has been successful in both neuroscientific and clinical applications. We propose an enhancement of this model with a local connectivity parameter that better accords with the known structure of white-matter. In addition to providing diffusion tensor parameter estimation the calculation provides the probability that a given pixel is connected to one of its nearest neighbors. These probabilities can be used in further calculations to determine the probability of connectivity between different brain regions.

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14:00 3313. White Matter Tract Probability Atlas Derived from Diffusion Tensor Tractography of a Large Population Catherine Lebel1, Luis Concha1, Gaolang Gong1, Christian Beaulieu1 1University of Alberta, Edmonton, Canada

Brain white matter is usually crudely parcellated based on lobar location in existing human brain atlases. Recent attempts to create a more detailedwhite matter atlas based on information derived from diffusion tractography have been reported, but are limited by small sample sizes. We investigated the spatial variability in standard space of thirteen white matter structures defined by tractography in a group of 254 healthy volunteers. The core of the white matter structures shows high spatial overlap amongst individuals, while the edges show high variability. Our results could provide valuable information for the interpretation of voxel-based analyses.

14:30 3314. Improving the Efficiency of Tractography by Combining DTI with Prospective Partial-Brain Q-Ball Imaging Jiancheng Zhuang1, Nicolas Lori1, Christine Vidal1, Hanna Damasio1 1University of Southern California, Los Angeles, USA

This study proposed to develop a method which combines the conventional DTI and a prospective partial-brain QBI to improve the efficiency of tractography. The non-Gaussian ADC profile detected from DTI data was used to indicate which brain region to be covered by QBI. The multiple wavevector fusion (MWF) algorithm was performed in the combination of data, and multiple FACT algorithm was applied in fiber tracking. The quality of connectivity detection in this approach is sufficiently high, and the scan time is reduced by about 65.3% when compared with a similar QBI with the whole brain coverage.

15:00 3315. Connectivity-Based Probabilistic Parcellation of the Striatum in Human Brain by Diffusion Tensor Imaging mingguo qiu1, qiyu li1, jian wang2, bing xie2, shaoxiang zhang1 1Third military medical university, chongqing, People's Republic of China; 2southwest hospital of Third military medical university, People's Republic of China

The aim is to investigate the corticostriatal connections in human by DTI. The results showed the frontal projections were located to the head of the caudate nucleus and the superior part of the putamen, the insular projections to the lateral striatum, the projections from the parietal, temporal and occipital lobes overlapped to the posterior part and the inferior part of the striatum. M1 were connected to the posterosuperior part, SMA to the middle part and PMC to the anterior and posteroinferior striatum. The striatum have specific connections with the different cortex, connectivity-based probabilistic tractography and parcellation is valuable in the functional anatomy of human brain.

13:30 3316. Diffusion Tensor Imaging Fiber Tracking of the Nigro-Striatal Fiber Tract in the Monkey Brain Using Whole Body 7T Stephane Lehericy1, Essa Yacoub2, Eric Bardinet1, Romain Valabregue1, Chantal Francois1, Geoff Ghose2, Noam Harel2 1University Pierre and Marie Curie, Paris, France; 2University of Minnesota, Minneapolis, Minnesota, USA

In this work, we used 7T whole body and diffusion tensor imaging (DTI) to reconstruct the nigro-striatal fiber tract in the anesthetized macaque brain. DTI was performed using a single shot SE acquisition. The nigro-striatal fiber tract was reconstructed between the segmented substantia nigra and lenticular nucleus. The tract coursed from the medial part of the substantia nigra anteriorly toward the medial part of the globus pallidus. DTI reconstruction of the nigro-striatal fiber tract provides a marker of the nigro-striatal pathway that can be used to study basal ganglia pathology such as Parkinson’s disease.

14:00 3317. High Resolution Probablistic Tractography in Whole, Fixed, Human Brain Using Diffusion-Weighted Steady-State Free Precession Jennifer A. McNab1, Saad Jbabdi1, Sean C.L. Deoni, 12, Gwenaelle Douaud1, Timothy E.J. Behrens1, Karla L. Miller1 1University of Oxford, Oxford, UK; 2Institute of Psychiatry, King's College, University of London, London, UK

This study presents a robust method for estimating the principal diffusion direction from multi-angle DW-SSFP data and demonstrates probabilistic tractography at sub-millimeter resolution in a whole, fixed human brain.

14:30 3318. Atlas-Based Reference Tracts Improve Automatic White Matter Segmentation with Neighbourhood Tractography Susana Muñoz Maniega1, Mark E. Bastin1, Andrew M. McIntosh1, Stephen M. Lawrie1, Jonathan D. Clayden2 1University of Edinburgh, Edinburgh, UK; 2UCL , London, UK

Neighbourhood tractography is a novel technique that aims to automatically segment the same fasciculus in different subjects by scoring the similarity between a predefined “reference tract” and a group of candidate tracts generated with different initial seed points. In the current work we present a means of improving the technique by generating the reference tract from an anatomical atlas. Using diffusion data from 50 volunteers we found that atlas-generated reference tracts improved the segmentation results in the four fasciculi examined, obtaining lower variation of FA within the group and percentages of visually plausible tracts of up to 82%.

15:00 3319. Using BCP Index to Evaluate Coregistration Methods in Existing SPM2 Shiou-Ping Lee1, Kao-Lun Wang1, Chung-Ming Chen2, Wen-Yih Isaac Tseng3 1Far Eastern Memorial Hospital, Taipei, Taiwan; 2National Taiwan University Hospital, Taipei, Taiwan; 3National Taiwan University Medical College, Taipei, Taiwan

A novel indices, Bundle Curvature Profile (BCP), was proposed as the basis to quantify the similarity of four fiber bundles to distinguish geometric significant difference. In this study, we corrected diffusion tensor imaging data using four different SPM2 built-in coregistration functions, i.e., normalized mutual information (NMI), mutual-information (MI), entropy correlation coefficient (ECC) and normalized correlation coefficient (NCC). We also applied coherence index (CI) to evaluate the accuracy of fiber tractography in corpus callosum. In conclusion, the proposed BCP index is also capable in revealing the difference between four coregistration functions which is consistent with the results from CI index whereas the similarity of fiber tracking using NCC correction method is higher than ECC, MI and NMI.

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Crossing Fibers & Non-Tensor Approaches Hall D Wednesday 13:30-15:30

13:30 3320. Fibre Orientation Probability Maps from Q-Ball and the Model-Based Bootstrap – a Potential Segmentation Tool Hamied Ahmad Haroon1, Karl V. Embleton1, Geoff J M Parker1 1The University of Manchester, Manchester, UK

Model-based residual (MBR) bootstrap enables quantification of the uncertainty in the inferred fibre orientation for probabilistic fibre tracking using a single HARDI dataset. Here we present probability maps of observing n fibre orientations estimated by MBR bootstrapping over i iterations in every voxel. These maps provide information for the classification of tissues based on their microstructural orientation complexity. The probability of finding any given configuration reflects the underlying tissue microscopic complexity, macroscopic partial volume, and data noise levels. This information will be of use in probabilistic tractography and in monitoring changes in tissue complexity due to disease or developmental processes.

14:00 3321. 4th Order Diffusion Tensor Estimation and Application Aurobrata Ghosh1, Maxime Descoteaux1, Rachid Deriche1 1INRIA, Sophia Antipolis – Méditerranée, Sophia Antipolis, France

We review and compare the existing methods for 4th order diffusion tensor imaging. We also propose an extension to the Riemannian framework developed for classical 2nd order DTI to the space of 4th order tensors. We test the methods on synthetic HARDI data, and on real brain data. In conclusion our experiments confirm that our Riemannian extension is capable of detecting fiber crossings, is the only algorithm that guarantees positive definite diffusion and is also computationally viable to be practicable.

14:30 3322. Denoising HARDI Coefficients Using Spherical Wavelet Lifting Sofia Olhede1, Brandon Whitcher2 1University College London, London, UK; 2GlaxoSmithKline, London, UK

We propose to estimate the diffusion distribution at each voxel by using a discrete wavelet transformation on the sphere, combined with an estimation procedure that is adapted to the Rician distribution. To respect the underlying sampling scheme and avoid smoothing out details in Q-space we construct a discrete wavelet transform using lifting.

15:00 3323. How Fast Can PAS Go? Ken Earl Sakaie1 1The Cleveland Clinic, Cleveland, Ohio, USA

High angular resolution diffusion imaging, combined with advanced postprocessing methods, can resolve crossing fibers. Of the large number of postprocessing methods, Persistent Angular Structure (PAS) has desirable properties in terms of angular resolution, accuracy, and robustness against noise, but the publicly available PAS calculation software can require weeks to months to analyze a typical brain dataset on a single processor. We show that coding the PAS calculation using widely available nonlinear optimization code can speed up the computation considerably, making this powerful method an option for more widespread use.

13:30 3324. Bootstrap Methods for Estimating Uncertainty in Constrained Spherical Deconvolution Fiber Orientations Ben Jeurissen1, Alexander Leemans2, J-Donald Tournier3, 4, Jan Sijbers1 1University of Antwerp, Antwerp, Belgium; 2School of Psychology, Cardiff University, Cardiff, UK; 3Brain Research Institute, Melbourne, Australia; 4University of Melbourne, Melbourne, Australia

Monte Carlo simulations were used to assess the accuracy and precision of bootstrap estimates of the uncertainty associated with brain white matter fiber orientations derived from diffusion weighted MRI using the new high angular reconstruction technique called constrained spherical deconvolution (CSD). We studied the accuracy and precision of these estimates as a function of repeated acquisitions, bootstrap realizations and inter-fiber angle. We showed an improvement of the accuracy of the uncertainty estimates of CSD fiber orientations, using an adaptation of the bootstrap called bootknife. Estimation of uncertainty is very important when fiber orientations are used in white matter fiber tractography, since errors are known to propagate.

14:00 3325. CSF Partial Volume Effect for Diffusional Kurtosis Imaging Caixia Hu1, Jens H. Jensen1, Maria Fatima Falangola1, Joseph A. Helpern1 1Center for Biomedical Imaging, New York, New York, USA

It is well known that CSF partial volume effects affect the fractional anisotropy (FA) and mean diffusivity (MD) values measured with diffusion tensor imaging (DTI). Prior studies have shown how to assess this quantitatively by comparing results from conventional DTI with those from fluid-attenuated inversion recovery (FLAIR) DTI In this study, we applied a recent generalization of DTI called diffusional kurtosis imaging (DKI) to obtain measurements of FA, MD, and mean kurtosis (MK) in human brain with and without FLAIR and found MK to be a more robust measurement with regard to CSF contamination than either MD or FA.

14:30 3326. Voxel Based Topometry of the ADC Profiles: Collapsing of the Dimensionality Oleg Petrovich Posnansky1, Nadim Jon Shah1 1Institute of Neurosciences and Biophysics (Medicine), Research Centre Juelich, Juelich, Germany

We explore the complex geometry of the apparent diffusion coefficient (ADC) profiles and introduce a set of measures and their topological characteristics – non-integer dimensions. Using the step-by-step scale blowing sphere method we analyse the random spatial structure of the ADC profiles and present maps of indices obtained by the proposed algorithm. The maps correlate with the anatomical structure of the brain to different extents and provide more detail non-Gaussian information about brain architecture.

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15:00 3327. A Simple Method for ODF Reorientation After Deformable Imaging Registraton Jinsuh Kim1, Madhura Ingalhalikar2, Vincent A. Magnotta2, Andrew L. Alexander3 1University of Iowa, Iowa City, Iowa, USA; 2University of Iowa, USA; 3University of Wisconsin, Madison, Wisconsin, USA

We propose a simple and efficient method of orientation distribution function reorientation that allows correct estimation of fiber distribution by deforming high angular resolution diffusion imaging data and applied diffusion gradient direction based on the high dimensional transformation.

13:30 3328. Comparison of Directional Diffusion Kurtoses and Diffusivities in EAE- Induced Spinal Cord Matthew Man Hin Cheung1, 2, Edward Sai Kam Hui1, Wutian Wu1, Ed X. Wu1 1The University of Hong Kong, Pokfulam, Hong Kong

Understanding the complex pathology of MS is important in treatment strategies. In this experiment, diffusion kurtosis imaging (DKI) was applied to ex-vivo EAE rat spinal cord samples. The DK tensor and directional kurtoses were computed. The differences between the EAE and the normal were evaluated. The directional kurtosis analysis was shown to possess high sensitivity, thus potentially capable of better differentiating MS pathology and understanding the disease.

14:00 3329. Diffusional Kurtosis Approximation of the Orientation Distribution Function in the Human Brain Mariana Lazar1, Jens H. Jensen1, Joseph A. Helpern1 1New York University School of Medicine, New York, USA

The Orientation Distribution Function (ODF) is used to describe the directionality of multimodal diffusion in regions with complex fiber architecture. Here, we present an approximation for the ODF of water diffusion from diffusional kurtosis imaging (DKI). The DKI-based ODF approximation is decomposed into two components representing the Gaussian and non-Gaussian (NG) diffusion contributions, respectively. Orientation maps obtained for in-vivo brain imaging data demonstrate multiple fiber components in brain regions with complex anatomy, with the NG-ODF being the most sensitive to profiling the fibers’ directions. The results appear to be in agreement with known white matter architecture.

14:30 3330. Simulation Study of Kurtosis Measurements in MR Diffusion Kurtosis Imaging Kyle Ho Yiu Cheng1, 2, Ed X. Wu1 1The University of Hong Kong, Pokfulam, Hong Kong

Monte Carlo simulation was performed in 1D space to study the spin diffusion, kurtosis characteristics, spin dephasing and MR signal attenuation in compartment-restricted diffusion environment. The apparent kurtosis was computed based on DKI formulation and compared to the true kurtosis and calculated from the actual diffusion displacement profiles. The simple results revealed that errors can be present in estimating true diffusion kurtosis by the apparent kurtosis. Choices of diffusion weighting parameters affect the outcomes. Both apparent diffusion kurtosis measurement and true diffusion kurtosis are not entirely intrinsic to the tissue structures because they also depend on the MR parameters. Therefore, cautions must be taken in the quantitative interpretation of kurtosis measurements in DKI experiments.

15:00 3331. Diffusion Kurtosis Imaging (DKI) of in Vivo Human Brain at 7 T Eric Edward Sigmund1, Caixia Hu1, Mariana Lazar1, Maria Fatima Falangola1, Jens H. Jensen1, Joseph A. Helpern1 1New York University, New York, New York, USA

Diffusion kurtosis imaging (DKI) has been performed in healthy volunteer in vivo brain in a 7 T scanner and 24-channel head coil. DKI provides all of the information in DTI in addition to higher order structural contrast determined by non-Gaussian diffusion. High parallel imaging factors were used to mitigate high field EPI image artifacts. Mean diffusivity MD, fractional anisotropy FA, and mean kurtosis MK were consistent with results at 3 T. MD showed comparable white matter / gray matter values, FA was elevated in WM and negligible in GM, and MK was nonzero and distinct in both tissue types.

Restricted Diffusion Hall D Wednesday 13:30-15:30

13:30 3332. A Statistical Approach for Creating Anisotropy Maps of the Brain Using Q-Space Diffusion Weighted Images Siamak Pourabdollah-Nejad1, 2, Quan Jiang1, 3, Douglas C. Noll2, Guang Liang Ding1, Michael Chopp1, 3 1Henry Ford Hospital, Detroit, Michigan, USA; 2University of Michigan, Ann Arbor, Michigan, USA; 3Oakland University, Rochester, Michigan, USA

In this abstract, a new method for creating anisotropy maps of the brain in introduced. In this method q-space data of the brain is acquired and as a measure of anisotropy, the deviation of the diffusion vectors from a sphere is calculated and is used for creating the new map which we have named Standard-Deviation map. Comparison of our map with other conventional maps such as the FA map shows that the new map can identify regions with crossing fibers more realistically. We have validated our method with histology and q-space MR images of a rat with traumatic brain injury.

14:00 3333. Probing Restricted Microcompartments with Double PGSE Noam Shemesh1, Yoram Cohen1 1Tel Aviv University, Tel Aviv, Israel

The double PGSE (d-PGSE) sequence was used to study water diffusion in 20ìm microtubes. Indeed we found, as predicted by a recent simulation, that a negative diffraction pattern occurs. The results of non-collinear d-PGSE (i.e. d-PGSExz or d-PGSEzx ) were found to be identical and independent of the mixing time (tm). The signal decay and the diffraction patterns of the collinear directions (i.e. d-PGSExx) depend on tm. Future work in micro scale phantoms and neuronal tissues will demonstrate whether d-PGSE can overcome some of the limitations of s-PGSE experiments.

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14:30 3334. The Dependency of the MR Indices, Observed by High B-Value Q-Space Diffusion MRS on Fiber's Orientation Amnon Bar-Shir1, Yoram Cohen1 1Tel-Aviv University, Tel-Aviv, Israel

The present study examines the effect of the rotational angle, α, on the apparent diffusion coefficient, extracted from low b-values and on the root mean square displacement (rmsd) of the fast- and the slow-diffusing components extracted from high b-value q-space MR diffusion experiments performed on optic nerves. The rmsd of the slow-diffusing component exhibits the most significant dependence on α. This phenomenon was found for both mature and newborn optic nerves and for short and long diffusion times. Our findings imply that the rmsd of the slow-diffusing component is the best predictor for restriction and fiber's orientation.

15:00 3335. In Vivo High Resolution Q-Space Imaging of the Spinal Cord Injury in Nonhuman Primates Keigo Hikishima1, 2, Masaya Nakamura, Kanehiro Fujiyoshi, Masayuki Yamada, 2, Kazuya Kitamura, Suketaka Momoshima, Kazuo Yagi, Norikazu Tamaoki2, Yoshiaki Toyama, Hideyuki Okano 1Keio University School of Medicine, Sinjuku, Japan; 2Central Institute for Experimental Animals, Kawasaki, Japan

q-space imaging(QSI) enables us to detect the size of microstructure quantitatively and has been used gradually. However, there is no report about in vivo QSI of the spinal cord (SC) in Nonhuman primates. To evaluate the structural changes of the injured SC in the same animal longitudinally, we performed in vivo high resolution QSI of both intact and injured spinal cords in common marmosets and confirmed the accuracy of QSI through histology. As the results, high Resolution QSI map reflected the histological changes of the injured SC and was useful for its evaluation.

13:30 3336. A Spectral Filtering View of Diffusion Gradient Encoding Andrew JM Kiruluta1 1Harvard University, Cambridge, Massachusetts, USA

Diffusion imaging gradients serve to spectrally filter the temporally evolving diffusion tensor in the spectral domain. In this formulation, the design of diffusion sensitizing gradients is reduced to the problem of adequately sampling q-space in the spectral domain and hence one of designing a suitable filter. The practical limitations imposed by the requirement for delta function type diffusion sensitizing gradients to adequately sample q-space, can be relaxed if these impulse gradients are replaced with chirped oscillatory gradients.

14:00 3337. A Two-Compartment Model to Accurately Characterize Extra- And Intra-Cellular Spaces in Neural Tissue with Q-Space Imaging Henry H. Ong1, Felix W. Wehrli1 1University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA

Knowledge of white matter (WM) intra-cellular volume fraction and mean axon diameter (ICF and MAD) would provide important insight into injury and pathology. Q-space imaging (QSI) offers potential for indirect assessment of WM architecture but is complicated by signal from both extra- and intra-cellular spaces (ECS and ICS). Here, we use a two-compartment model to fit QSI molecular displacement distribution profiles from WM tracts in healthy mouse spinal cords to characterize the ECS and ICS. The measured ICF and MAD values showed excellent agreement with histology and demonstrate the feasibility of this method to extract non-destructively accurate WM architecture information.

Methods for Brain Arterial Spin Labelling Hall D Thursday 13:30-15:30

13:30 3338. Reliability and Reproducibility of Arterial Spin Labeling Perfusion Measures Assessed with a Multi-Center Study Thomas Liu1, Christina Wierenga2, Bryon Mueller, Jiong Jiong Wang, Gary Glover, James Voyvodic, Doug Greve, Jessica Turner, Cynthia Wible, Greg Brown, Function BIRN 1UCSD Center for Functional MRI, La Jolla, California , USA; 2UCSD Dept. of Psychiatry, La Jolla, California , USA

Arterial spin labeling MRI was used to obtain whole brain cerebral blood flow measures in a sample of 11 healthy volunteers who were scanned at three different sites participating in the Function BIRN study. There was not a significant effect of site on the cerebral blood flow measures, but there was a significant effect of subject.

14:00 3339. Pseudo-Continuous Arterial Spin Labeling at 7T Wen-Ming Luh1, Tie-Qiang Li1, Eric C. Wong2, Peter A. Bandettini1 1National Institutes of Health, Bethesda, Maryland, USA; 2University of California, San Diego, La Jolla, California , USA

Arterial spin labeling (ASL) techniques benefit from the increase in T1 at high field strength. However, the SNR improvement at high field can only be realized with an optimal tag duration which also increases with field strength. At 7T, the optimal tag duration can reach 3 and 1.3 sec for continuous and pulsed ASL, respectively. Pseudo-continuous ASL allows for long tag duration without special hardware. However, both B1 and B0 inhomogeneity with the volume excitation coil toward the tagging location presents challenges for PCASL. Here we implemented PCASL at 7T and demonstrated these effects and a way to mitigate them.

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14:30 3340. Mapping PASL Arterial Transit Time in Normal Human Brain Using [15O]water PET Maolin Qiu1, J Wang1, H Kim1, R E. Carson1, R T. Constable1 1Yale University School of Medicine, New Haven, Connecticut, USA

Arterial transit time (ATT) in pulsed arterial spin labeling (PASL) refers to the time it takes the arterial blood to travel from the labeling site to the capillaries. It defines the earliest time data acquisition could start after IR labeling and is required for CBF quantification. ATT measurements that use the PASL sequence suffer from the low sensitivity of PASL and intravascular contamination. ATT is usually determined and used on a per-slice basis and within slice variations in ATT are not considered. The use of improper ATT values can introduce errors in CBF quantification. In this study we used CBF measured by PET to calculate the ATT on a per-voxel basis, which allows us not only to examine the in-slice ATT variability, but also to optimize the imaging parameters for PASL. More important, the ATT map, once estimated, can be used for CBF mapping in a similar PASL imaging setup, providing voxel based ATT values.

15:00 3341. Tagging Efficiency Improvement Using Velocity-Matched Pseudo-Continuous Arterial Spin Labeling and VERSE Wen-Ming Luh1, Eric C. Wong2, S Lalith Talagala1, Peter A. Bandettini1 1National Institutes of Health, Bethesda, Maryland, USA; 2University of California, San Diego, La Jolla, California , USA

Pseudo-continuous arterial spin labeling can be performed with standard commercial scanners without special hardware. Moreover, several characteristics of the RF and gradient pulses can be adjusted for optimal performance. However, changes in velocity through the cardiac cycle can compromise tagging efficiency especially during systolic phases. It is possible to improve tagging efficiency for high velocity spins by increasing RF amplitude at the cost of SAR. Fortunately, the increase in SAR can be mitigated with VERSE transformation if needed. Here we dynamically raised PCASL RF amplitude according to the measured velocity profile at labeling location with cardiac gating and VERSE modification.

13:30 3342. Influence of Cardiac Cycle on Velocity Selective Arterial Spin Labeling Wouter M. Teeuwisse1, 2, Mark A. van Buchem1, Matthias J. van Osch1 1Leiden University Medical Center, Leiden, Netherlands

In velocity selective arterial spin labeling (VS-ASL), blood that flows faster than a predetermined cut-off velocity is labeled. Because blood velocity is not constant, labeling efficiency may vary over cardiac cycle. In this study, dependency of perfusion signal on cardiac cycle was investigated. VS-ASL was performed with cardiac triggering at various trigger delays. In all volunteers mean slice perfusion showed variation up to ± 20% compared to mean perfusion with trigger delay at diastole. Variation over cardiac cycle was different between subjects. When cardiac triggering is applied, a trigger delay of 300 ms gives highest label efficiency in most cases.

14:00 3343. Achieving Late Inflow Delay in Pseudo-CASL 3D GRASE Using a Hybridized Labeling and Background Suppression Scheme María A. Fernández-Seara1, Jiongjiong Wang2, David A. Feinberg3, John A. Detre2 1Center for Applied Medical Research, University of Navarra, Pamplona, Spain; 2University of Pennsylvania Medical Center, Philadelphia, Pennsylvania, USA; 3Advanced MRI Technologies, Sebastopol, California , USA

A modified version of the pseudo-CASL background suppressed 3D GRASE sequence is presented. This sequence, which allows acquisition of perfusion maps with long post-labeling delay, in a short scan time, will be useful in cases in which arterial transit time is prolonged as occurs in cerebro-vascular disease or acute stroke.

14:30 3344. An Efficient Labeling Scheme for CASL for Use with Multiple, Independently Switched Coils Ralf Berthold Loeffler1, Ruitian Song1, Yong Zhang1, Adam Martin Winchell1, 2, Josef Pfeuffer3, Zoltan Patay1, Claudia Maria Hillenbrand1 1St. Jude Children's Research Hospital, Memphis, Tennessee, USA; 2University of Memphis and UTHSC Joint Biomedical Engineering Program, Memphis, Tennessee, USA; 3Siemens Medical Solutions, Erlangen, Germany

A new paradigm for efficient multi-coil continuous arterial spin labeling is presented. The paradigm utilizes signal from every excitation to calculate the contribution of a particular artery. The paradigm was implemented on a standard clinical scanner for 3 label coils, which led to a paradigm length of 8. The label coils could be switched independently by a custom built RF cabinet that was controlled by the scanner. Volunteer measurements demonstrated good separation of vascular territories in the brain.

15:00 3345. Continuous Artery-Selective Spin Labeling (CASSL) Applied to Distal Branches of Intracranial Arteries Michael Helle1, 2, David Norris2, Karsten Alfke1, Olav Jansen1 1Christian-Albrechts-Universität, Kiel, Germany; 2FC Donders Centre for Cognitive Neuroimaging, Nijmegen, Netherlands

We demonstrate the feasibility of CASSL to selectively label blood of individual branching intracranial arteries even in the immediate vicinity of other small vessels in-vivo. A saturation of the magnetization in non-selected vessels depends basically on the labeling gradient orientation, its rotation frequency and the distance from the labeling focus. By empirical optimization of these key parameters the labeling of small arteries with diameters of 3 mm and less, that branch from the media and anterior cerebral arteries, mainly to A2/A3 and M2/M3 segments respectively, is demonstrated.

13:30 3346. A Simple Model to Measure Arterial Cerebral Blood Volume by Arterial Spin Labelling Roman Wesoλowski1, Penny A. Gowland1, Susan T. Francis1 1University of Nottingham, Nottingham, UK

A method of quantifying LL-FAIR data for arterial cerebral blood volume (CBVa) using simple correction factors is described. Monte-Carlo simulations are used to compare the results of fitting CBVa using this simplified method with the standard stepwise compartment model based on Bloch equations. We have used the new method to quantify (CBVa) from experimental LL-FAIR data acquired at 3 T during a 4.8 s visual stimulus.

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14:00 3347. A Probabilistic Approach to Model-Free Arterial Spin Labeling Perfusion Quantification Michael A. Chappell1, Salima Makni1, Saad Jbabdi1, Mark W. Woolrich1 1University of Oxford, Oxford, UK

Traditional 'kinetic curve' model based methods for ASL analysis are not ideal for perfusion quantification in pathological tissue, since assumptions about healty tissue are made in the models. Recently the 'model-free' approach to ASL analysis has been demonstrated, this treats the signal as the convolution of an arterial input and redsidue function. Here we present an improved probabilistic based method for model-free ASL analysis. The advantage of this approach is that residue function shape can be determined under the constraint of temporal smoothness, without neededing to set the functional form a priori and without the regularisation aretefacts of a singular value decomposition approach. The method also includes a procdure to determine arterial feeding regions, for arterial input function assignment, based on blood arrival time information. Ultimately the method is designed to provide robust perfusion measurments from ASL data even in pathological tissue.

14:30 3348. Post-Processing Correction for Extended Data Acquisition in Whole Brain 3D Quantitative PULSAR Imaging Neville Dali Gai1, John Anthony Butman1 1National Institutes of Health, Bethesda, Maryland, USA

Here we devise a simple first-order correction scheme for extended data acquisition 3D PULSAR brain perfusion imaging. Extended data acquisition (~600ms) introduces some ambiguity in the transit time used in quantitative CBF determination. By applying an exponential correction for tagged blood decay in hybrid space, we attempt to reduce bolus dispersion effects during acquisition. Corrected values were compared with corresponding single slice imaging. CBF values in 3D slices were lower than corresponding single slice acquisition values due to blurring. However, after correction the values showed better agreement with the single slice acquisition case.

15:00 3349. Comparison of Quantitative Perfusion 3D IR-PULSAR with Multi-Slice 2D and Single Slice Imaging Neville Dali Gai1, Sardha Lalith Talagala1, John Anthony Butman1 1National Institutes of Health, Bethesda, Maryland, USA

In this study, CBF values obtained with extended 3D data acquisition (for whole brain coverage) QUIPSSII IR-PULSAR are compared with values obtained with multi-slice 2D (MS-2D) and single slice acquisition. Excellent agreement in gray matter (GM) global average CBF values was found between the 3D and 2D-MS acquisition schemes. There was good agreement between the GM CBF values from 3D slices and corresponding single slice acquisitions. Values were slightly lower in the 3D case due to blurring. White matter CBF values were very low for all acquisition schemes due to much longer transit delays (~1.6s). Whole brain quantitative perfusion imaging with 3D PULSAR is feasible as long as the above limitations are kept in mind.

Diffusion Acquisition Hall D Thursday 13:30-15:30

13:30 3350. Simulations of SNR Efficiency of DTI Using Parallel Imaging and RFOV Acquisition at 3 T and 7 T Carolin Reischauer1, Robert Stefan Vorburger1, Bertram Jakob Wilm1, Thomas Jaermann1, Philipp Staempfli1, Peter Boesiger1 1ETH and University of Zurich, Zurich, Switzerland

The transition to ultra-high field strengths promises a boost in the SNR for diffusion tensor imaging. Image acquisition typically relies on single-shot EPI which is hampered by susceptibility-induced distortions and T2* related blurring, especially at high field strengths. These challenges can be quite effectively addressed by partial Fourier and reduced FOV acquisition, as well as parallel imaging methods. In the present work simulations at 3 T and 7 T were performed to investigate under which conditions the SNR gain can be tapped, provided that higher reduction factors have to be applied at ultra-high field strengths.

14:00 3351. Apparent Diffusion Behaviors Modulated by Distant Dipolar Field in Solution NMR Shuhui Cai1, Guiping Shen1, Congbo Cai1, Zhong Chen1 1Xiamen University, Xiamen, People's Republic of China

A modified CRAZED sequence was designed to observe and characterize apparent diffusion behaviors of signals from intermolecular double-quantum coherences during the mixing period. It is found that their apparent diffusion behaviors are different from conventional single-quantum coherences, and different orientation of diffusion weighting gradients relative to coherence selection gradients results in different apparent diffusion behaviors. This indicates that the apparent diffusion behavior is influenced by the distant dipolar field.

14:30 3352. Optimizing Diffusion Measurements for Large-Scale Multi-Centre Trials: A Magnims DT MRI Sequence Elisabetta Pagani1, Jochen G. Hirsch2, Marco Rovaris1, Achim Gass2, Petra Pouwels3, Stephan Roosendaal3, Frederik Barkhof3, Federica Agosta1, Domenico Caputo4, Antonio Giorgio5, Jacqueline Palace5, Silvia Marino6, Nicola De Stefano6, Massimo Filippi1 1Scientific Institute H San Raffaele, Milan, Italy; 2University Hospital Basel, Basel, Switzerland; 3VU University Medical Centre, Amsterdam, Netherlands; 4Scientific Institute Fondazione Don Gnocchi, Milan, Italy; 5University of Oxford, Oxford, UK; 6University of Siena, Siena, Italy

The aims of the present study were: a) the development of an optimal acquisition scheme of diffusion tensor (DT) magnetic resonance imaging (MRI) for large-scale trials (considering the time issue in the context of “multi-sequence scans”) and b) the evaluation of both the feasibility of the sequence set-up on various scanners and the inter-centre reproducibility of DT-derived metrics. Twenty-nine healthy subjects were studied in 7 MRI centres using a standardized DT-MRI sequence. The inter-scanner variability of DT-derived quantities was found to be lower for anisotropy than mean diffusivity measures, especially when using 1.5 T magnets.

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15:00 3353. General-Purpose Diffusion Simulation for Any Sequence Using Monte Carlo Approach Optimized for Parallel and Multi-Core Processors Donghui Yin1, Jonathan C. Sharp2, Boguslaw Tomanek2 1National Research Council Institute for Biodiagnostics, Winnipeg, Canada; 2National Research Council Institute for Biodiagnostics (West), Calgary, Canada

Our aim in this work is to extend a general-purpose integrated MR simulation / MR console environment to include diffusion-weighting using the Monte Carlo stochastic method. The general-purpose nature requires that any sequence written for the MR console is also available for simulation without additional simulation programming or expertise required of the user. We have demonstrated that the Monte Carlo method can reliably produce diffusion weighting in many cases. Our implementation has been optimized for multi-core processors so that the performance can automatically improve as industry makes new CPUs available.

13:30 3354. Correlation Time Diffusion Coefficient Brain Mapping: Combined Effects of Magnetization Transfer and Water Micro-Kinetics on T1 Relaxation Hernan Jara1 1Boston University Medical Center, Boston, Massachusetts, USA

Purpose: To develop a T1 relaxation theory incorporating the combined effects of magnetization transfer and water micro-kinetics, for the purpose of computing accurate correlation time diffusion coefficient (D(CT)) maps of structurally complex biological tissues. Methods: Images obtained with the mixed-TSE sequence were postprocessed for generating PD, T1, and T2 maps and used for computing maps of the correlation time diffusion coefficient with the developed T1-MT theory. Results: Excellent quantitative agreement is found in the brain relative to standard pulsed-field-gradient MRI. Conclusion: Magnetization transfer has a substantial effect on T1 relaxation for tissues containing a restricted pool of 1H protons.

14:00 3355. Single-Shot Multi-Echo Parallel EPI for DTI with Improved Efficiency and Accuracy Roger Nana1, Tiejun Zhao2, Xiaoping Hu1 1Georgia Institute of Technology / Emory University, Atlanta, USA; 2Siemens Medical Solutions, Malvern, USA

We introduce a multi-echo parallel EPI acquisition strategy to enhance SNR while maintaining the advantages of parallel EPI. We show that an appropriate echo combination strategy can provide significant gains in SNR as compared to using only one echo. This SNR gain can be utilized to reduce the number of measurements often required to ensure adequate SNR for accurate calculation of various DTI measures or to improve spatial resolution. Furthermore, the multiple echoes can be used to derive a T2 map, providing additional information that might be useful in some applications.

14:30 3356. Towards Quantitative Diffusion-Weighted Chemical Shift Imaging of Brain Metabolites Itamar Ronen1, Dae-Shik Kim1 1Boston University School of Medicine, Boston, Massachusetts, USA

Diffusion tensor imaging (DTI) has become a ubiquitous MRI modality for the assessment of microstructural properties of tissue. Its explanatory power, however, is limited by the lack of compartmental specificity of the water MR signal. The possibility of gaining compartment-specific diffusion information has been explored using diffusion weighted spectroscopy of intracellular metabolites. In this work we explore for the first time the feasibility of obtaining quantitative diffusion information on intracellular metabolites using diffusion weighted chemical shift imaging (CSI). The main hurdles for reliable diffusion measurements, i.e. loss of phase consistency and signal across the acquisition are addressed.

15:00 3357. Fractional and Relative Anisotropies Are Depended on Selecting the EPI Readout Gradient Modulation Frequency at 4 Tesla MRI Geon-Ho Jahng1, Michael W. Weiner2, Norbert Schuff2 1East-West Neo Medical Center, Kyung Hee University, Seoul, Republic of Korea; 2University of California,San Francisco, San Francisco, California , USA

To investigate effects of EPI readout gradient modulation frequency on the accuracy of diffusion tensor (DT)-MRI measurements, we studied the relationship between the EPI bandwidth and the Nyquist ghost for a spin echo EPI acquisition with DT preparation on a spherical water phantom and nine volunteers. In result, there were significant effects on the bandwidths for the b=800 data and for the b=0 data on the phantom study. On the human study, EPI bandwidth variations substantially corrupted diffusion anisotropy indexes. The effect can be minimized by tuning the modulation frequency of the EPI readout gradient.

13:30 3358. Turboprop Diffusion Tensor Imaging for Computational Design of Drug Transport in Brain Xiaodong Guo1, Mahadevabharath R. Somayaji2, Andreas A. Linninger2, Jia-Hong Gao1, Richard D. Penn1 1University of Chicago, Chicago, Illinois, USA; 2University of Illinois at Chicago, Chicago, Illinois, USA

Three dimensional subject-specific brain anatomy is reconstructed from Turboprop DTI images. Rigorous first principles physical transport phenomena are applied to predict the fate of a high molecular weight neurotropic factor infused into the midbrain based on DT-MRI derived drug and tissue properties. For predicting drug distribution in humans, comprehensive transport models considering heterogeneous and anisotropic brain properties derived from patient-specific images have not been adequately researched in open literature before.

14:00 3359. Optimization of DTI Imaging Parameters Using Prior Information of Fiber Orientation Wei Gao1, Hongtu Zhu, Hongyu An, Weili Lin 1University of North Carolina-Chapel Hill, Chapel Hill, USA

The aim of this study was to develop a new method for determining optimal imaging parameters for diffusion tensor imaging. The accuracy and precision of DTI experiments depend on both the choice of the imaging parameters and the noise propagation in tensor estimation process. In this work, we propose to combine both of these two processes during the optimization processes. Additionally, information on fiber orientation distribution is also taken into account during the optimization processes. As a result, the diffusion encoding scheme could efficiently sample those “densely oriented cone areas” in a shorter data acquisition. Thus, it leads to the efficient use of imaging acquisition time, which is crucial for pediatric imaging.

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14:30 3360. Turbo Spin Echo Diffusion Tensor Imaging (TSE-DTI) in the Brain at 3 T and 7 T Eric Edward Sigmund1, Daniel Kim1, Flavio Tulio Braga1, Jian Xu2 1New York University, New York, New York, USA; 2Siemens Medical Systems, New York, New York, USA

This study used a single-shot turbo spin echo sequence for diffusion tensor imaging (TSE-DTI) in healthy volunteer brain scans in clinical scanners at 3 T and (for the first time) at 7 T, in comparison with echo-planar imaging (EPI-DTI), which suffers from known susceptibility artifacts at high field. T2 blurring was significantly reduced in TSE images using a separate T2 map and k-space-based deconvolution procedure. At 3 T , EPI-DTI and TSE-DTI colormaps were of comparable quality. At 7 T and at higher resolution, EPI-DTI suffered significant image distortions, while TSE-DTI showed correct anatomical proportions and uniform white matter sensitivity.

15:00 3361. Noise Bias Reduction and Parallel Imaging for the Measurement of Diffusion Decay Guillaume Gilbert1, Georges A. Haddad1, Gilles Beaudoin1 1Centre Hospitalier de l'Université de Montréal, Montreal, Canada

In this abstract, we investigate the applicability of a noise bias reduction method for the accurate measurement of diffusion decay. This method, based on an improved combination of signals from array coils and complex averaging, is used in conjunction with standard imaging and GRAPPA parallel imaging. While some statistical noise bias correction methods developed for standard imaging are no longer exact when parallel imaging is used, this approach is shown to provide an accurate estimation of bi-exponential diffusion parameters, even when combined with GRAPPA parallel imaging.

13:30 3362. High-Resolution Diffusion Tensor Imaging Reveals Sub-Structure Whithin Human Hippocampus in Vivo David Andrew Porter1, David Atkinson2, Rod Scott2, 3, Chris A. Clark2 1Siemens Medical Solutions, Camberley, UK; 2University College, London, UK; 3Great Ormond Street Hospital NHS Trust, London, UK

Diffusion tensor imaging has the potential to provide detailed information about the hippocampus that may be important in a number of diseases linked to hippocampal abnormality. However, previous human DTI studies in vivo have had difficulty in visualising hippocampal sub-structures due to the low resolution associated with single-shot EPI. This study uses the readout-segmented EPI method for high resolution DTI of the hippocampus and demonstrates some of this sub-structure in fractional anisotropy maps.

Cerebral Perfusion & Diffusion Imaging of Animal Models Hall D Thursday 13:30-15:30

13:30 3363. Impact of Parallel Imaging Acceleration on Perfusion Measurements of the Rodent Brain David Ratering1, Christof Baltes1, Ivana Kotevic1, 2, Markus Rudin1, 2 1University and ETH Zurich, Zurich, Switzerland; 2University Zurich, Zurich, Switzerland

Dynamic susceptibility contrast MRI in small rodents demands for high temporal resolution to detect the fast change of the signal intensity at the first passage of the contrast agent. The feasibility of acquiring a densely sampled signal time curve using parallel imaging acceleration has been demonstrated in humans. In this work, in vivo experiments were carried out to investigate the influence of SENSE and GRAPPA acceleration on perfusion measurements of the rat brain. In addition, computer simulations were performed to test the feasibility of multi-slice imaging at reasonable temporal resolution.

14:00 3364. Characterising the Origin of the Arterial Spin Labelling Signal in MRI Using Multi-Echo Acquisitions Jack A. Wells1, 2, Mark F. Lythgoe1, Mankin Choy1, David G. Gadian1, Roger J. Ordidge1, David L. Thomas1 1University College London, London, UK

We estimate the relative signals deriving from labelled spins in the vasculature and in the intra and extracellular space within the tissue, by calculating the T2 of the ASL signal at a variety of post labelling delays and tagging durations with and without bipolar crusher gradients, in the rat brain. The results provide evidence for rapid exchange and suggest that the vascular signal is comprised of both arterial and venous blood. The relative proportion of extra- to intracellular signal is ~ 2 times greater for the labelled spins in comparison to the control even at extended tagging duration (3s) and post labelling delay (0.3s).

14:30 3365. Novel Cardiac Spin Labeling (CSL) for CBF MRI in Mice Eric R. Muir1, Qiang Shen1, Timothy Q. Duong1 1Emory University, Atlanta, Georgia, USA

Continuous arterial-spin-labeling with a separate neck coil is generally more sensitive relative to the single-coil technique. Cerebral-blood-flow (CBF) MRI application in mice however has been limited by the close proximity between the neck and the brain coil, which results in saturation of the brain signals by the neck coil. We introduce an alternative approach to overcome this limitation by placing the labeling coil at the heart position, which we termed the Cardiac Spin Labeling (CSL) technique. This approach was applied to image quantitative basal blood flow and physiologically evoked blood flow changes in normal mice at high spatial resolution.

13:30 3366. The Nuts and Bolts of Implementing a Two-Coil CASL Method for CBF Measurement on a 9.4T/30cm Scanner Rongyan Zhang1, Yuan Ma1, Guangping Dai2, Kathleen Yin1, Shi-Jiang Li1 1Medical College of Wisconsin, Milwaukee, Wisconsin, USA; 2Massachusetts General Hospital, Charlestown, Massachusetts, USA

We recently implemented the two-coil CASL method on our Bruker Biospin 30cm bore 9.4T animal MRI system, and obtained excellent CBF images and time-series. The purpose of this abstract is to share our experience, the challenges we met and present our solutions. We have found that sometimes seemingly trivial details are key to the successful implementation. It is our hope that this information can be helpful to more research and application sites to utilize this powerful technique in their fMRI studies.

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14:00 3367. Whole Brain Diffusion Tensor Image Analysis by Tract-Based Spatial Statistics (TBSS) in a Kainic Acid Rat Epilepsy Model ex Vivo Kimmo K. Lehtimäki1, Teemu P. Laitinen1, Alejandra Sierra1, Jari Nissinen1, Asla Pitkänen1, Olli Gröhn1 1A.I.Virtanen Institute for Molecular Sciences, University of Kuopio, Kuopio, Finland

We implemented a whole brain voxelwise statistical analysis method, tract based spatial statistics (TBSS), into the rat epilepsy model for the comparison of ex vivo diffusion tensor data between control and kainic acid animals. Today, no reports of TBSS in the rodent brain exist. With this approach we revealed both brain regions that are known to be associated with epilepsy and those that have not been earlier connected with epileptogenesis or epilepsy. TBSS combined with animal models has great potential to serve as a robust screening method to guide tedious histological analysis to novel target areas in the brain.

14:30 3368. Toward a Comprehensive 3D DT-MRI Atlas for Marmoset Monkey Brain Hao Huang1, Xiaoqin Wang2, Madeleine Chollet2, Susumu Mori2 1UT Southwestern Medical Center, Dallas, Texas, USA; 2Johns Hopkins University, Baltimore, Maryland, USA

Marmoset has been more and more commonly used as an animal model in neurobiological study. The digital 3D comprehensive atlas for marmoset brain appears to be an urgent need. DTI can generate different contrasts of images which provide rich information of not only cortical and subcortical gray matter but also individual white matter fiber bundles. In this study, we acquired ex vivo DTI data of adult marmoset head. Important neural structures were annotated, segmented and reconstructed. The atlas is being built for the purposes of education, anatomical reference, data registration and image guided invasive surgery.

15:00 3369. Comparing Corticocortical Interconnection Information from Tracer Studies and Probabilistic Tractography in the Postmortem Macaque Brain Hamied Ahmad Haroon1, David M. Morris1, Alexander Kaiser2, Mark Augath2, Nikos K. Logothetis, 12, Geoff J M Parker1 1The University of Manchester, Manchester, UK; 2Max Planck Institute for Biological Cybernetics, Tuebingen, Germany

We present a study attempting to validate the corticocortical connection information obtainable from diffusion-weighted MR data. We have implemented probabilistic tractography in data acquired in a macaque model and compared this with connection information in a database of invasive tracer studies in the same model. The nature of the corticocortical interconnection information gained from probabilistic tractography is different to that gained from invasive studies, the latter also being sparse. Our results using the LVE00a parcellation scheme indicate that probabilistic tractography is able to give statistically comparable information on corticocortical interconnections to invasive tracer studies.

13:30 3370. Diffusion Tensor Tractography of Primate Visual Pathway Masayuki Yamada1, 2, Suketaka Momoshima3, Yoshitaka Masutani4, Kanehiro Fujiyoshi3, Keigo Hikishima, 23, Osamu Abe4, Masaya Nakamura3, Shigeki Aoki4, Norikazu Tamaoki5, Hideyuki Okano3 1Fujita Health University, Toyoake, Japan; 2Central Institute for Experimental Animals, Kawasaki, Japan; 3Keio University, Shinjuku-ku, Japan; 4University of Tokyo Hospital, Bunkyo-ku, Japan; 5Central Institute for Experimental Animals, Kawasaki, Japan

We evaluated the reliability of non-human primate visual pathway depicted by diffusion tensor tractography (DTT) with the assistance of manganese-enhanced magnetic resonance imaging (MEMRI) tract tracing. The DTT depicted the typical primate retinogeniculate pathways branching bilaterally at the optic chiasm and the MEMRI tract tracing also revealed this bilateral innervation. The configurations visualized by the two modalities were nearly identical and these morphological findings were corresponded with those obtained from previous histopathological studies. Thus, the findings of our study suggested that the DTT methods play a crucial role in the morphological analysis of the non-human and/or human primate visual pathways.

14:00 3371. Corpus Callosum Injury and Seizures in WAG/Rij Rats: Correlation Between DTI and Disease Phenotype Halima Chahboune1, 2, Asht Mangal Mishra1, Xenophon Papademetris1, Fahmeed Hyder1, Hal Blumenfeld1 1Yale University School of Medicine, New Haven, USA

In vivo DTI has great potential for assessing morphological changes in the CNS. Here we show alterations in morphology of neuronal pathways in a well-established animal model for human absence epilepsy. Control and epileptic rats (28-30 weeks) were studied with DTI ex vivo. We report that the tissues integrity of the corpus callosum was perturbed in epileptic rats. In conclusion, we have shown that DTI is sensitive for the detection of white matter changes in the WAG/Rij rat model of absence epilepsy.

14:30 3372. Three Dimensional Stereotactic Atlas of Developing C57BL/6J Mouse Brains Using Diffusion Tensor Microimaging and Micro-Computed Tomography Manisha Aggarwal1, Jiangyang Zhang1, Susumu Mori1, 2 1Johns Hopkins University School of Medicine, Baltimore, USA; 2Kennedy Krieger Institute, Baltimore, USA

Mouse brain atlases have an important role in targeting brain structures during surgical operations in experimental mice models. A three-dimensional stereotactic surgical atlas of C57BL/6J mouse brains at six developmental stages: postnatal day 7 (P7), P14, P21, P28, P63 and P140 was developed, using high resolution diffusion tensor imaging (DTI) and micro-computed tomography (MicroCT) of mouse head specimens. DTI generated sharp white and gray matter contrasts throughout development, even in early postnatal mouse brains prior to myelination. The atlas can be used to determine the exact stereotactic coordinates of any location within the brain relative to reference skull landmarks.

15:00 3373. Diffusion Tensor Imaging Reliably Detects Experimental Traumatic Axonal Injury and Indicates Approximate Time of Injury Christine Louise Mac Donald1, Krikor Dikranian1, Sheng-Kwei Song1, Philip Bayly1, David Holtzman1, David Brody1 1Washington University, St. Louis, USA

Diffusion tensor imaging (DTI) was used to characterize the temporal changes occurring following traumatic brain injury in an experimental mouse model. DTI signal changes correctly predicted the presence of axonal injury and quite confidently predicted the approximate timing of injury. The results suggest that DTI could be used to assess axonal injury clinically if similar signal changes were found in humans following traumatic brain injury.

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13:30 3374. Effects of Environment Enrichment on Hypoxia-Induced Injury to Corpus Callosum and Cingulate in C57B/L6 Mice Halima Chahboune1, 2, Laura Ment1, William Stewart1, Douglas L. Rothman1, Fahmeed Hyder1, Micheal L. Schwartz1 1Yale University School of Medicine, New Haven, USA

Using in vivo DTI we examined morphological effects of environmental enrichment in a clinically relevant neonatal model of chronic sublethal hypoxia (CSH) injury to developing brain. Hypoxia (<10%) at the 3rd day (P3) after birth in C57B/L6 mice for a week provides an injury model which replicates neuropathologic findings that accompany preterm birth. Normal and CSH mice raised in non-enriched and enriched conditions were studied at P36 and P51. We found that enriched environment enhances tissue anisotropy within the corpus callosum and cingulate in both groups and may circumvent the delayed development observed in CSH mice.

14:00 3375. Manganese Enhanced MR Neuronal Tract Tracing: A Passive Stochastic Process Andrew Sheridan Lowe1, 2, Ian D. Thompson, 23, Nicola R. Sibson2 1University College London, London, UK; 2Univerisity of Oxford, Oxford, UK; 3Kings College London, London, UK

Manganese enhanced MR tract tracing is based upon the intra-cellular uptake, transportation and subsequent accumulation of manganese at terminal fields. A recent study suggests neuronal activity is blocked, while axonal transport is unaffected, by concentrations of Mn required for imaging. There remains speculation, however, regarding the relative contribution of passive diffusion as transportation rates were determined over the distal optic nerve. The current study reports the consequences of pharmacological blockade of retinal ganglion activity on remote terminal field enhancement. The paradox of blocked activity and hence expected blocked intra-cellular uptake in the context of evident terminal field enhancement is discussed.

14:30 3376. Blood-Flow Magnetic Resonance Imaging of the Retina Haiying Cheng1, Yingxia Li1, Timothy Q. Duong1 1Emory University, Atlanta, Georgia, USA

This study describes a novel MRI application to image basal blood flow, and physiologically induced blood-flow changes in the retina. Continuous arterial-spin-labeling technique with a separate neck coil for spin labeling was used to image blood flow of the rat retina at 90x90x1500-ƒÝm resolution. The average blood flow was significantly higher (6.3¡Ó1.0mL/g/min under 1% isoflurane) than the brain (1 mL/g/min). Breathing oxygen decreased blood flow 25¡Ó6% relative to baseline (air). Breathing 5%CO2 increased blood flow 16¡Ó6%. Blood-flow MRI has the potential to provide unique insights into retinal physiology and serve as an early biomarker for retinal diseases.

15:00 3377. Cerebral Blood Flow MRI in Rats Using Cardiac Spin Labeling Technique Qiang Shen1, Eric Muir1, Timothy Q. Duong1 1Emory Unviersity, Atlanta, Georgia, USA

Continuous arterial-spin-labeling with a separate neck coil is generally more sensitive relative to the single-coil technique, but the two coils need to be actively decoupled to avoid coil-to-coil electromagnetic interaction. Additionally it is difficult to measure cerebellum blood flow with the two coil technique, because the neck coil does not label the vertebral arteries which supply the cerebellum. We introduce a new approach to overcome these limitations by placing the labeling coil at the heart position. We termed this approach the Cardiac Spin Labeling (CSL) technique. We applied this technique to image basal CBF and physiologically evoked CBF changes in normal rats.

Fetus & Neonate: Normal, Injury, Animal, Human Hall D Monday 14:00-16:00

14:00 3378. Multi-Spectral Analysis of Relaxation Time Maps on Fetal Baboon Brains Feng Liu1, 2, Marianne Garland1, Yunsuo Duan1, 2, Raymond Stark1, Bradley Peterson1, 2, Alayar Kangarlu1, 2 1Columbia University Medical Center, New York, New York, USA; 2New York State Psychiatric Institute, New York, New York, USA

Relaxation times T1 and T2 are sensitive to the rapid changes in the brain tissues during early life. We acquired sequential measurements of T1 and T2 in fetal baboon brains at different gestational ages. Either T1 maps or T2 maps provided better contrast than the relaxation time weighted images. Nevertheless, we used both relaxation time maps to extract multi-spectral maps as a quantitative diagnostic tool for differentiation of immature brain tissues. Both prenatal and postnatal data are presented to demonstrate the sensitivity of this tool to the process of early brain development.

14:30 3379. Distinguishing Primary from Non-Primary Visual Cortical Areas by DTI at Early Stages of Brain Development Christopher D. Kroenke1, Erin N. Taber1, Andrew K. Knutsen2, Philip V. Bayly2 1Oregon Health & Science University, Portland, Oregon, USA; 2Washington University, St. Louis, Missouri, USA

Water diffusion anisotropy is observable within the developing cerebral cortex, and becomes diminished with axonal/dendritic differentiation. Here we report cortical diffusion anisotropy measurements in post-mortem, early postnatal ferret brain (developmentally equivalent to mid/late gestational primate brain). Cortical surface modeling procedures are used to define visual area boundaries in brains from several stages of development. Differences in cortical diffusion anisotropy are found between primary and non-primary areas, reflecting differences in histological structure, or rate of development. These findings buttress prior observations in non-human primate brain tissue, and suggest that DTI can be of utility for delineating boundaries between functional cortical areas.

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15:00 3380. DTI Studies with Immunohistological Correlation in the Developing Human Frontal Cerebrum Rakesh Kumar Gupta1, Richa Trivedi1, Nuzhat Husain2, Sona Saksena2, Savita Srivastava2, Mandakini Pradhan1, Vinita Das2, Gyanendra K. Malik2, Ram Kishore Singh Rathore3 1Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India; 2CSMM University, Lucknow, India; 3Indian Institute of Technology, Kanpur, India

In-vivo DTI was performed on freshly aborted 43 human fetuses with GA of 15–37 weeks. Out of them immunohistochemical analysis by using glial fibrillary acid protein (GFAP), and neuron specific enolase (NSE) antibodies was performed on 35 fetuses. Regions of interest were placed on cortical, subplate, intermediate and germinal matrix zone of frontal lobe. Peak value of cortical fractional anisotropy (FA) and maximal expression of GFAP was observed in frontal cortex of 26 weeks of GA fetus. Significant correlation was observed between FA in germinal metrics and number of NSE positive cells present in the germinal matrix zone. The ability to noninvasively monitor neuronal migration and maturation processes in vivo should greatly improve our understanding of the normal developmental pattern of the cerebrum in human fetal brain.

15:30 3381. Diffusion Tensor Imaging (DTI) of the Developing Human Cerebellar Cortex with Immunohistological Correlation Nuzhat Husain1, Sona Saksena2, Savita Srivastava1, Richa Trivedi2, Vinita Das1, Mandakini Pradhan2, Ankur Purwar3, Gyanendra K. Malik1, Ram Kishore Singh Rathore3, Rakesh K. Gupta2 1CSMM University, Lucknow, India; 2Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India; 3Indian Institute of Technology, Kanpur, India

DTI was performed on spontaneous abortion or intrauterine dead human fetuses (n=28) with gestational age (GA) of 20-37 weeks. Fractional anisotropy (FA) values were quantified on the cerebellar cortical regions. Immuohistochemistry using Glial Fibrillary Acid Protein (GFAP) antibody was also performed on fetal brains (n=22) ranging from 20-36 weeks GA. The observed increase in cortical FA values during the early third trimester appears to be associated with the radial organization of granule cell neurons seen on GFAP stained Bergmann glial fibers. This study demonstrates the migrational and maturation changes in the developing cerebellar cortex using DTI and its confirming on GFAP immunostaining.

14:00 3382. Diffusion Tensor Imaging and Immunohistochemical Studies in the Developing Human Cerebellar Peduncles Rakesh K. Gupta1, Sona Saksena1, Nuzhat Husain2, Savita Srivastava2, Richa Trivedi1, Vinita Das2, Mandakini Pradhan1, Ankur Purwar3, Gyanendra K. Malik2, RKS Rathore3 1Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India; 2CSMM University, Lucknow, India; 3Indian Institute of Technology, Kanpur, India

Diffusion tensor imaging was performed on spontaneous abortion or intrauterine dead human fetuses (n=23) with gestational age (GA) of 20-37 weeks. Fractional anisotropy (FA) values were quantified on the middle cerebellar peduncles (MCP). Immunohistochemistry using anti-Myelin Basic Protein (MBP) antibody was also performed on fetal brains (n=9) ranging from 19-37 weeks GA. The observed maximum increase in FA values during the late third trimester of gestation, reaching a plateau by 37 weeks in MCP reflects myelination of axons during late third trimester which is confirmed by the expression of myelinated fibers in the MCP at 32 and 37 weeks GA. This study will provide a normative database of developing cerebellar white matter using DTI and its confirming on MBP immunostaining.

14:30 3383. In-Vivo Subplate Development in Preterm Infants Latha Srinivasan1, Giuliana Durighel1, Serena J. Counsell1, Joanna M. Allsop1, Julie A. Fitzpatrick1, A David Edwards1, Mary A. Rutherford1 1Imperial College London, London, UK

Subplate is a transient neuronal layer that relays thalamic inputs to the developing cortex. In-vivo quantification of 80 T2-weighted MR images between 25 and 45 weeks showed that the subplate was maximal in length at 30 weeks, after which it decreased in length and was restricted to gyral crests. During development the depth remained constant whereas there were regional variations in all subplate measurements. Infants with lesions had decreased depth and T2-intensity. At term age preterm infants had increased subplate depth, length and T2-intensity compared to term controls suggesting a combination of delayed and abnormal subplate maturation in preterm infants.

15:00 3384. Corroboration of Disorganized Fetal Brain Lamination on Postmortem MR and DTI with Autopsy Findings Elysa Widjaja1, Susan Blaser2, Patrick Shannon3 1Hospital for Sick Children, Toronto, Canada; 2Hospital for Sick Children, Canada; 3Mount Sinai Hospital, Canada

Postmortem MR and diffusion tensor imaging in fetuses with brain malformations

15:30 3385. Investigation of Neonate Brain Development Enabled by Tract-Oriented Quantification Mahnaz Maddah1, Andrea U.J. Mewes2, 3, Heidelise Als2, Gloria McAnulty2, Eric L. Grimson1, Simon K. Warfield2 1Massachusetts Institute of Technology, Cambridge, Massachusetts, USA; 2Harvard Medical School and Children’s Hospital,, Boston, Massachusetts, USA; 3Charite, Berlin, Germany

Tract-based quantitative analysis reveals developmental differences that are not identified by ROI-based methods. Spatial patterns of the tract development are clearly observed once the parameters of interest are plotted along the tract arc length. Comparison across different subjects or at different time points are easily achieved by mapping the corresponding cluster centers. The proposed approach opens new possibilities for more accurate analysis of neonate brain development.

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14:00 3386. Thalamic Development in Preterm Infants During the Third Trimester Latha Srinivasan1, Ciara Abbott1, Serena J. Counsell1, Joanna M. Allsop1, Julie A. Fitzpatrick1, Giuliana Durighel1, A David Edwards1, Mary A. Rutherford1 1Imperial College London, London, UK

Thalamic inputs are necessary for proper development of functional cortical columnar units. Thalamic quantification in 80 T1-weighted images of preterm infants between 25 and 45 weeks postmenstrual age showed that the thalamic growth was 0.49 cm3/week. Further exploration in a group of longitudinally scanned infants confirmed that both the total thalamic volume and rate of growth were significantly reduced in the presence of significant cerebral lesions. This combination of absolute volume reduction and failure of growth may explain the thalamic volume reductions seen in preterm infants at term equivalent age as shown by a variety of automated and manual methods.

14:00 3387. Evidence of Thalamocortical Fibers Maturation in Early Human Brain Development Assessed by Diffusion Tensor Imaging Vincent Denolin1, Xavier De Tiège2, Anne Pardou3, Danielle Balériaux2, Patrick Van Bogaert2, Thierry Metens2, Alec Aeby2 1Philips Medical Systems Benelux, Brussels, Belgium; 2ULB-Hopital Erasme, Brussels, Belgium; 3ULB-Hopital Erasme, Belgium

Early studies on brain maturation with DTI were based on measurements in pre-defined regions of interest (ROI), which introduce a bias due to a priori hypotheses about the localization of maturational changes. Therefore we used a voxel-based approach, as known as statistical parametric mapping (SPM), to detect maturational changes in a population of preterm and term newborns, without prior prescription of the brain area to be analyzed. We showed that, besides regions previously identified using ROI analyses, i.e. motor and somatosensory tracts, optic radiation and corpus callosum, significant maturational changes also occur in the thalamus between 34 and 41 weeks gestational age.

14:30 3388. Evolution of MR DTI Changes in Neonatal Rats After Mild Hypoxic-Ischemic Insult Jian Yang1, 2, Cheng Wang Jin2, Pek Lan Khong, Gang Niu2, Ed X. Wu1 1Department of Electrical and Electronic Engineering,The University of Hong Kong, Hong Kong, People's Republic of China; 2The First Hospital of Xi'an Jiaotong University, Xi'an, People's Republic of China

7-day-old mild hypoxic-ischemic (H-I) rats (n=12) were studied at 7T with diffusion tensor imaging (DTIs) in day 1, 3 and 7 post H-I insult. The apparent diffusion coefficient (ADC), fractional anisotropy (FA) and directional diffusivities (¦Ë// and ¦Ë¡Í) values were measured in white matter (WM) and gray matter (GM) lesion and their contralateral side. In day 1, the ADC, FA and ¦Ë// values showed significant decrease in GM lesion whilst WM lesion only showed a significant ADC increase. In day 3, the significant FA decrease and ¦Ë¡Í increase were found in GM lesion. Significant ADC and ¦Ë¡Í increase, and FA decrease were observed in the ipsilateral WM. By day 7, all DTI values were not statistically different between two hemispheres. Thus DTI is a sensitive method to study the early transient GM and WM changes after mild H-I insult by probing the microstructural changes.

15:00 3389. In-Vivo Magnetization Transfer Brain MRI of Mice with Neonatal Hypoxia-Ischemia Ali Fatemi1, 2, Mary Ann Wilson1, Seth A. Smith1, Susumu Mori1, Jiangyang Zhang1, Michael V. Johnston1, Michael T. McMahon1 1Johns Hopkins University, Baltimore, Maryland, USA; 2Massachusetts General Hospital, Boston, Massachusetts, USA

The objective of this study was to develop a quantitative in-vivo imaging technique for assessment of outcome in mice with perinatal brain injury. Magnetization Transfer (MT) Imaging was performed 3 weeks after a hypoxic-ischemic insult in CD-1 pups and showed decreased MTR values on the affected hemisphere as well as in the corpus callosum and internal capsule. This work is the first demonstration that perinatal brain injuries can be highlighted in mice using MT imaging.

14:00 3390. Significance of Lactate in Patients with a Central Pattern of Hypoxic Ischemic Injury on DWI Within the First 3 Days of Life Bindu Setty1, 2, Eva-Maria Ratai, 23, Pallavi Sagar1, 2, Kalpathy S. Krishnamoorthy, 2, Ellen P. Grant1, 2 1Massachusetts General Hospital, Boston, Massachusetts, USA; 2Harvard Medical School, Boston, Massachusetts, USA; 3Massachusetts General Hospital – A.A. Martinos Center for Biomedical Imaging , Charlestown, Massachusetts, USA

Eight neonates with hypoxic ischemic injury were studied within the first3 days of life using MRI (DWI and MRS). The objective of this study was todetermine, if the absence of lactate predicts good outcomes in patientswith decreased diffusion in the ventrolateral thalamus. No significantcorrelation was obtained between lactate ratios in the deep gray nucleiand ADC values. In addition, there was no correlation between presence orabsence of lactate and the extent of DWI abnormality or clinical outcome.In fact, 2 patients that died showed no lactate on MRS but had extensiveareas of decreased diffusion.

14:30 3391. Temporal Changes in Brain Water Diffusivity in Neonatal Meningitis Rakesh K. Gupta1, Richa Trivedi1, Gyanendra K. Malik2, Abhishek Yadav1, Kashi N. Prasad1, Ram KS Rathore3 1Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India; 2Chhatrapati Shahuji Maharaj Medical University, Lucknow, India; 3Indian Institute of Technology, Kanpur, India

Periventricular white matter of neonatal brain is known to be vulnerable to oxidative and hypoxic/ischemic injury secondary to neuro-infections. Serial diffusion weighted imaging (DWI) was performed on 45 neonates with meningitis at two time points: 1) at the time of diagnosis; and 2) after 3 weeks of antibiotic treatment. T1/T2 images showed abnormalities along with pseudo-normalization of apparent diffusion coefficient (ADC) values on 2nd study in those patients (29 %), who showed low ADC values with normal T2/T1 imaging on first MRI. The temporal variation of ADC in this study is suggestive of hypoxia related injury and may be responsible for long term neurological sequel in these neonates.

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Optic Nerve Hall D Monday 14:00-16:00

14:00 3392. Axial Diffusivity in Acute and Isolated Optic Neuritis Robert T. Naismith1, Junqian Xu1, Abraham Snyder1, Tammie Benzinger1, Joshua Shimony1, Kathryn Trinkaus1, Anne H. Cross1, Sheng-Kwei Song1 1Washington University, Saint Louis, Missouri, USA

Diffusion Tensor Imaging was performed in 4 cases of acute and isolated optic neuritis in order to determine whether axial and radial diffusivity have a prognostic role for long-term clinical function.

14:30 3393. Quantification of Glaucomatous Optic Atrophy Utilizing High Resolution MRI of the Optic Nerve Thorsten Alexander Bley1, 2, Mathias Weigel1, Miriam Gaggl1, Robin Munk1, Mathias Langer1, Juergen Hennig1, Wolf Lagreze1 1University of Freiburg, Freiburg, Germany; 2University of Wisconsin - Madison, Madison, USA

With age and under certain pathologic conditions, such as glaucoma the diameter of the optic nerve may change. This study evaluates MRI of the retro-bulbar optic nerve as a surrogate marker for axonal atrophy in glaucoma. 3 Tesla MRI of the optic nerve in 47 patients with glaucoma depicted the optic nerve and its sheath within the full intra-orbital track with high contrast in 1.5 sec. acquisition time per slice. Imaging findings correlated well with severity of glaucoma.

15:00 3394. HR-MRI Demonstrates Abnormalities of Motor Nerves and Extraocular Muscles in Patients with Congenital Complex Strabismus Yuan Feng Man1, Chang Zhen Wang1, Hong Yong Jiao1 1Tongren hospital, Beijing, People's Republic of China

In this article we use MRI to explore the abnormalities of oculomotor and extraocular muscles of congenital complex strabismus, the objective is to study the relationship of the nerve and the corresponding extraocular muscles.

Advanced Spinal Cord Imaging Hall D Monday 14:00-16:00

14:00 3395. Rapid and High-Resolved Diffusion Tensor Imaging of Mouse Lower Brain and Cervical Spinal Cord Virginie Callot1, Guillaume Duhamel1, Patrick J. Cozzone1 1Centre de Résonance Magnétique Biologique et Médicale (CRMBM) - UMR CNRS 6612, Marseille, France

Mouse diffusion tensor imaging (DTI) of both the brain and the spinal cord (SC) may reveal useful information on tissue damage consequent to inflammatory or degenerative diseases. To rapidly assess the geometrical and functional extent of the pathology, a large coverage and sufficient spatial resolution are required. Standard pulse sequences preclude obtaining such requirements as they do not allow achieving sufficient signal to noise ratio within an acceptable scan-time. In this work, we propose to use a spin-echo (SE) EPI DTI-based sequence to obtain spatially resolved (140x140x750 µm3) DTI metrics of both the cerebellum and cervical SC within 30 minutes.

14:30 3396. Accurate Measurement of Mean Axon Diameter with Q-Space Diffusion MRI Henry H. Ong1, Felix W. Wehrli1 1University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA

Accurate knowledge of white matter (WM) mean axon diameter (MAD) would provide important insight into injury and pathology. The signal decay at low q-values in q-space diffusion experiments, which can be modeled as a Gaussian, contains MAD information, but is complicated by signal from both extra- and intra-cellular spaces. Here, we use one- and two-compartment models to fit decay curves from WM tracts in healthy mouse spinal cords to measure MAD. The measured MAD values showed excellent agreement with histology, particularly the two-compartment fit, and demonstrate the feasibility of this method to extract accurate WM architecture information non-destructively.

15:00 3397. Mouse Lumbar Spinal Cord Blood Flow (SCBF) Measurements by Arterial Spin Labeling Guillaume Duhamel1, Virginie Callot1, Frank Kober1, Patrick J. Cozzone1 1CRMBM, CNRS 6612, Faculté de Médecine, Université de la Méditerranée, Marseille, France

A recent work has demonstrated the feasibility of mouse SC blood flow (SCBF) measurement with arterial spin labeling (ASL) using a flow-sensitive alternating inversion recovery (FAIR) technique at the cervical level. Accurate measurements of SCBF within structures of the cord were obtained. The assessment of perfusion measurements at lower levels of the cord (thoracic, lumbar) is of interest for numerous disease models (contusion, ischemia…) but challenged by amplified bulk motion. The present study demonstrates the feasibility of lumbar SCBF measurement by ASL. Good image quality was achieved and cervical and lumbar SCBF values were compared.

15:30 3398. A Diffusion and Perfusion EPI-Based MR Protocol for the Characterization of Rodent Spinal Cord Diseases Virginie Callot1, Guillaume Duhamel1, Frank Kober1, Patrick J. Cozzone1 1Centre de Résonance Magnétique Biologique et Médicale (CRMBM) - UMR CNRS 6612, Faculté de Médecine, Marseille, France

The purpose of this work was to give an experimental MR procedure that may be used to better characterize spinal cord (SC) diseases in which structural tissue damage and deficient blood supply are involved. Such a characterization has not been possible so far.In this study, we propose to perform spin-echo EPI Diffusion Tensor Imaging and quantitative perfusion imaging of the mouse spinal cord, with an in-plane resolution of 133x133 µm² and a total scan-time of 90 minutes. Imaging was performed at the cervical level, where spinal cord injury, infarction or tumor may easily occur.

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14:00 3399. Short Scan-Time Diffusion Tensor Imaging of the Mouse Thoracic and Lumbar Spinal Cord Using Echo Planar Imaging Virginie Callot1, Guillaume Duhamel1, Yann Le Fur1, Patrick J. Cozzone1 1Centre de Résonance Magnétique Biologique et Médicale (CRMBM) - UMR CNRS 6612, Faculté de Médecine, Marseille, France

Spin-Echo (SE) EPI technique applied to mouse cervical spinal cord (SC) imaging has recently been proposed and a 3 to 4 acquisition-time gain-factor was demonstrated as compared to conventional SE. However, the application of SE-EPI technique at lower SC levels is challenged by higher field heterogeneities and motion amplitude.The present study demonstrates that high-quality mouse SC DTI-EPI acquisitions at the thoracic and lumbar levels can be performed. A complete dataset (2 b-values, 6 encoding directions, 9 slices, 172x172x750 µm3 resolution) can be collected within 15 minutes. Moreover, by using outer volume suppression, 86x86 µm² in-plane resolutions can be achieved.

14:30 3400. Temporal Changes in Axial and Radial Diffusivities in a Rat Model of Wallerian Degeneration in the Spinal Cord Jiangyang Zhang1, Melina V. Jones1, Cynthia A. Deboy1, Daniel S. Reich1, Paul N. Hoffman1, Kazim A. Sheikh1, Susumu Mori1, Peter A.Calabresi1 1Johns Hopkins University School of Medicine, Baltimore, Maryland, USA

Diffusion tensor images of postmortem rat spinal cords were acquired after dorsal root axotomy. We found significant decreases in FA and axial diffusivity and a significant increase in radial diffusivity during the first three days after axotomy, followed by slow increase in radial diffusivity. MR findings were correlated with pathology in the dorsal column from 18 hours to 30 days after surgery. Our results suggest that axial diffusivity can detect very early axonal degeneration at different locations in the spinal cord, and the changes in radial diffusivity were complex and remain to be investigated.

15:00 3401. High Field MRI of the Acute Stage of Cervical SCI in the Rat Georgeta Mihai1, 2, Yvette S. Nout2, Petra Schmalbrock3, Jacqueline C. Bresnahan2, Michael S. Beattie2 1The Ohio State University , Columbus, USA; 2University of California San Francisco, San Francisco, USA; 3The Ohio State University, Columbus, USA

In this study the characterization of acute stage of cervical SCI was archived by imaging at 4.7T using a 3cm home built coil. Evolution of edema, cord swelling and hemorrhage was compared between two injured groups of animals, one that received 5% NaCl IV solution infusion and another one that received 0.9%NaCl starting at 30 minutes post injury. The eight hours continuous MRI scans revealed differences in term of injury evolution between the two groups. This work suggests that MRI can be used to monitor therapies and treatments aimed at reducing secondary injury in SCI.

15:30 3402. Biplanar Spinal Cord MRI in MS - Depiction of Cord Pathology and Improvement of Clinical Correlations Katrin Weier1, Alain Thoeni1, Yvonne Naegelin1, Michael Amann1, Jochen G. Hirsch1, Hüseyin Duyar1, Ludwig Kappos1, Wolfgang Steinbrich1, Ernst-Wilhelm Radue1, Achim Gass1 1University Hospital Basel, Basel, Switzerland

Biplanar spinal cord (SC) MRI of MS patients was performed in 202 MS patients. PD and T2-w in axial and sagittal planes were employed to visualize SC pathology thoroughly. Typical pathological findings (focal lesions, extent of diffuse hyperintensity, focal or generalised atrophy) were used to categorize patients according to a new SC abnormality score. The resulting scores showed a good correlation to clinical functional scores (EDSS and FS). Improved visualization of the pathological changes and their integration in a new abnormality score may overcome difficulties in detection and aid interpretation of SC MRI results.

14:00 3403. BOLD Signal Responses to Controlled Hypercapnia in Human Spinal Cord Julien Cohen-Adad1, 2, Claudine Gauthier1, 3, Habib Benali2, Serge Rossignol1, Richard D. Hoge3 1GRSNC, Department of Physiology, Faculty of Medicine, Université de Montréal, Montreal, Canada; 2INSERM U678, Université Pierre et Marie Curie (Paris VI), CHU Pitié-Salpêtrière, Paris, France; 3Unité de Neuroimagerie Fonctionnelle, CRIUGM, Université de Montréal, Montreal, Canada

We used hypercapnia to characterize the sensitivity of the BOLD method in human spinal cord. Results suggest that BOLD signal is highly dependent on the gross vascular anatomy of the spinal cord, limiting the sensitivity in grey matter since the precise vascular organization may vary among subjects. Moreover, negative BOLD was measured in various regions of the cord, possibly caused by blood-stealing, or by an increased in signal dephasing due to higher flow velocities in large vessels. The framework developed in this study will help future investigations aiming at characterizing the BOLD signal in the spinal cord.

14:30 3404. Magnetization Transfer (MT) Asymmetry in Human Cervical Spinal Cord Man Cheuk Ng1, Jun Hua2, Peter C.M. van Zijl2, Edward S. Yang3, Hong Hu1, Keith D. Luk1, Edmund Y. Lam1 1The University of Hong Kong, Pokfulam, Hong Kong, People's Republic of China; 2Johns Hopkins University, Baltimore, USA; 3ASTRI, Science Park, Shatin, Hong Kong, People's Republic of China

Magnetization transfer (MT) effect includes the interaction between bulk water and semisolid macromolecules (conventional MT) and the chemical exchange dependent saturation transfer (CEST) effect. MT asymmetry was investigated in human cervical spinal cord at 3T using low power off-resonance RF irradiation at different frequency offsets. Our results showed that the z-spectrum in gray/white matter was asymmetrical about the water resonance frequency (P < 0.001) with more saturation effect at lower frequencies (negative frequency offset) far from water and at higher frequencies (positive offset) close to water, which were attributed mainly to the conventional MT and CEST effects respectively.

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15:00 3405. Computational MR Image Analysis for Spinal Cord Injury Studies Kevin Ming1, 2, Rafeef Abugharbieh1, Claire F. Jones1, Andrew Yung1, Piotr Kozlowski1, Wolfram Tetzlaff1, Peter A. Cripton1 1University of British Columbia, Vancouver, Canada

We present a novel computational image analysis approach for studying and quantifying spinal cord deformations, in vivo, using magnetic resonance imaging (MRI) of rats. High field (7 Tesla) MR data is acquired and used to compute deformations of the spinal cord in its original physiological environment, for the first time, as opposed to traditional approaches in which animal spinal cords are exposed and directly subjected to a mechanical force. Image data was captured before and after a non-injurious deformation representative of that associated with mild myelopathy (pressure on the cord in vivo) were acquired using gradient echo FLASH T1-weighted sequence The proposed approach provides a new framework through which the causes, mechanisms, and tolerance parameters of sustained compression of the spinal cord and myelopathy, as well as the measures used in the study of neuroprotection and regeneration of spinal cord tissue, can be prospectively derived in a manner that ensures the bio-fidelity of the cord.

15:30 3406. Hyper-Acute Evaluation of Spared White Matter in Mouse Model Contusion SCI Using in Vivo DTI Joong Kim1, Hsiao-Fang Liang1, Sheng-Kwei Song1 1Washington University School of Medicine, St. Louis, Missouri, USA

Graded contusion spinal cord injury was generated at T9 spinal cord level of C57 BL/6 female mice. In vivo DTI was performed immediately after injury at 4.7 T magnet followed by perfusion and fixation. Spared white matter of contusion injured spinal cord was determined non-invasively using axial diffusivity thresholding. The neurofilament and myelin basic protein positive immunohistochemistry staining was performed along with the standard silver staining to assess spared white matter content. In vivo DTI determined spared white matter showed good agreement with that determined using histology.

Spectroscopy & Computer Aided Analysis of Brain Tumor Hall D Monday 14:00-16:00

14:00 3407. Amide Proton Transfer (APT) Imaging of Human Brain Tumors with B0 Inhomogeneity Correction Jinyuan Zhou1, 2, Jaishri Blakeley1, Jun Hua1, 2, Mina Kim1, 2, Peter C.M. van Zijl1, 2 1Johns Hopkins University, Baltimore, Maryland, USA; 2KKI, Baltimore, Maryland, USA

B0 field inhomogeneity is known to interfere with the quality of CEST-type experiments, especially for in vivo studies, such as APT imaging, because of the need to assign the water frequency in each voxel. We show here a practical six-offset scheme to acquire human brain high-SNR APT images. Eight brain tumor patients were scanned at 3T. Combined with the water frequency offset map fitted from an additional CEST spectrum, the method is able to correct for the artifacts produced by B0 field inhomogeneity on standard two-offset APT images.

14:30 3408. Spatial Correlation of Metabolic Abnormalities in Non-Enhancing Low Grade Gliomas Qian Zhao1, 2, Ying Lu1, Jiqian Fang3, Wei Bian1, Sarah Nelson1, Tracy McKnight1 1University of California, San Francisco, San Francisco, USA; 2School of Public Health,Sun Yat-Sen University, Guangzhou, People's Republic of China; 3School of Public Health,,Sun Yat-Sen University, Guangzhou, People's Republic of China

Grade 2 astrocytoma (AS) and oligodendroglioma (OD) are often similarly non-enhancing (NE) and appear although they convey different prognoses for patients. Studies have shown a link between the spatial correlation of MRS features and growth activity in NE glioma. We compared the magnitude and correlation of MRS metabolites in NE AS and OD. Compared with OD, the relative level of Cho and Cre throughout AS lesions was more uniform. AS were further distinguished by a negative correlation between NAA and Lac. The differences in the metabolic characteristics within the two tumor types may reflect differences in the underlying biology.

15:00 3409. 1H-MR Spectroscopy as a Cancer Biomarker for Anti-Angiogenic Treatment in Glioblastoma Hei-Soog Kim1, 2, Ciprian Catana2, Eva-Maria Ratai2, Wei-Ting Zhang2, Priscilla Yeo2, Meiyun Wang2, Tracy T. Batchelor2, Rakesh K. Jain2, A. Gregory Sorensen2 1Massachusetts Institute of Technology, Cambridge, Massachusetts, USA; 2Massachusetts General Hospital, Boston, Massachusetts, USA

A previous study demonstrated the efficiency of anti-angiogenic clinical trial in glioblastoma using MRI markers. However, there is a concern that the changes observed using standard MR imaging do not directly relate to tumor cell changes. This study suggests that 1H-MRS is a very promising method for assessing the response of cancerous tissue to anti-angiogenic treatment. NAA/Cho measured in twenty patients showed no significant changes until day 28 and decreased afterwards. The tumor is likely to regress after 28-56 days, later than the enhancement changes on the MRI. One probable interpretation of our data is that signs of tumor regression appear later, while those of tumor recurrence earlier on 1H-MRS than on MRI.

15:30 3410. Incorporation of MR Spectroscopic Imaging Into Gamma Knife Radiosurgery Treatment Planning Lawrence Ryner1, 2, Muoi Tran3, Herve Momo-Jeufack2, Jordan Hovdebo1, 2, Michael West2 1National Research Council Institute for Biodiagnostics, Winnipeg, Canada; 2University of Manitoba, Winnipeg, Canada; 3CancerCare Manitoba, Winnipeg, Canada

Infiltrative gliomas are known to extend beyond the area of contrast enhancement, however, conventional Gamma Knife treatment planning typically involves identifying the radiosurgical target volume on contrast-enhanced MR images. MRSI can show early biochemical changes useful for targeting abnormal tissue. We present further work in this area confirming the utility of MRSI in Gamma Knife treatment planning, as observed in patient MRSI datasets showing spectra from MRSI voxels (outside of and adjacent to the planned radiosurgical target volume) with abnormal choline to NAA ratios as compared to age and brain region-matched controls.

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14:00 3411. Interobserver Agreement for Cerebral Glioma Volumetrics on Conventional MR Imaging Gerard Thompson1, John Robert Cain1, Alan Jackson1, Samantha Jane Mills1 1University of Manchester, Manchester, UK

A number of groups have demonstrated that measurements of glioma tumour volume on magnetic resonance imaging are more valuable prognostically than simple uni- or bi-dimensional measurements such as the RECIST criteria. Such volumetric parameters will only be of value in clinical use and in further investigation if they can be reliably reproduced by different observers. This work tests for, and demonstrates, good interobserver agreement between non-expert radiologists employing a simple volumetric method on conventional MR imaging of cerebral gliomas.

14:30 3412. Towards Predicting Neoplastic Recurrence with Multi-Parametric MR Evangelia I. Zacharaki1, Ragini Verma2, Sanjeev Chawla2, Elias R. Melhem2, Ronald Wolf2, Christos Davatzikos2 1University of Pennsylvania , Philadelphia, Pennsylvania, USA; 2University of Pennsylvania, Philadelphia, Pennsylvania, USA

Treatment of brain neoplasms can greatly benefit from knowledge of the extent and degree of neoplastic infiltration. The current work is a preliminary study aiming to illustrate how the integration of multiple MRI parameters via sophisticated nonlinear pattern classification methods could be applied to predict possible neoplastic progression. The method incorporates high dimensional intensity features created from multiple MRI acquisition protocols (structural MRI as well as DTI) into a pattern classification framework, to obtain a voxel-wise probabilistic spatial map that reflects the likelihood of a region presenting neoplastic recurrence after resection.

15:00 3413. Qualitative and Quantitative Tumour Edge Characteristics for the Assessment of Glioma on Conventional MRI – Interobserver Agreement John Robert Cain1, Gerard Thompson1, Alan Jackson1, Samantha Jane Mills1 1University of Manchester, Manchester, UK

Tumour border sharpness coefficient (TBSC), and subjective qualitative measures such as descriptors of tumour margins have both shown potential in differentiating between histological and genetic subtypes of glioma. These techniques will only be of use if they are reproducible in the clinical setting. This study demonstrates excellent interobserver reproducibility for TBSC in tumours of all grades. Only T2W border descriptors showed poor reproducibility in grade IV tumours and may reflect the location of these tumour and their oedema to cortical and ventricular margins. All other qualitative descriptors demonstrated acceptable reproducibility in both low and high grade tumours.

15:30 3414. Computer-Aided Detection of Metastatic Brain Tumors Using Automated 3-D Template Matching Robert Ambrosini1, Peng Wang2, Balasubramanya Kolar1, Walter O'Dell1 1University of Rochester, Rochester, USA; 2University of Michigan, Ann Arbor, USA

Although screening for brain metastases using MR imaging is a critical component of the medical care for cancer patients, reading these images is both a time-consuming and subjective process when performed without computer assistance. We have developed an automated detection algorithm for brain metastases that is based upon 3-D template matching. The data collected on 22 patient datasets (1320 coronal MR slices) containing 161 total brain metastases show that we can achieve currently a sensitivity of 87.6% with a false positive rate of 0.58 per image slice. These results demonstrate our algorithm’s value as a clinical assist tool for radiologists.

14:00 3415. Nosologic Imaging of the Brain: Combined MRI and MRSI Segmentation and Classification Jan Luts1, Albert J. Idema2, Arend Heerschap2, Dirk Vandermeulen1, Johan Suykens3, Sabine Van Huffel3 1Katholieke Universiteit Leuven, Leuven , Belgium; 2University of Nijmegen, University Medical Center, Nijmegen, Netherlands; 3Katholieke Universiteit Leuven, Leuven, Belgium

In this study advanced methods from image processing and pattern recognition are applied to segment and classify brain tumours, thereby including spatial information. Both MRSI and MRI data are combined to produce higher resolution nosologic images. Furthermore, class probabilities are calculated for the segmented tumour region. A leave-one-patient-out evaluation procedure is performed. The segmentation and classification scheme are applied to patients with grade II glioma tumours, grade III glioma tumours, glioblastomas or meningiomas. The proposed method offers a new way to produce nosologic images, representing tumour heterogeneity and class probabilities, which may help clinicians in decision making.

MRA & Flow of Neurovascular Diseases Hall D Tuesday 13:30-15:30

13:30 3416. A Novel Technique of Cranial MR Angiography: Hybrid MRA Takao Kodama1, Takanori Yano1, Shozo Tamura1, Yoshio Machida2, Tokunori Kimura2 1Faculty of Medicine, University of Miyazaki, Miyazaki, Japan; 2Toshiba Medical Systems, Otawara, Japan

We developed a new MRA sequence, hybrid MRA (HMRA), combining the contrast of time-of-flight (TOF) and flow-sensitive black blood (FSBB) by using the dual-echo data acquisition. The gradient moment nulling (GMN) and dephasing gradient was applied to obtain the first echo and the second echo, respectively. Original images of the HMRA were made by subtracting the second-echo images from the first-echo images. This sequence was more sensitive to slow flow than 3D TOF MRA and seemed to be a feasible technique or evaluating steno-occlusive vascular disease.

14:00 3417. GRAPPA with a TWIST: Dynamic 4D CE MRA of the Cerebral Vasculature at Near Isotropic Resolution Jens Olaf Heidenreich1, Martin Blaimer1, Randall Kroeker, Gerhard Laub, Jeffrey L. Duerk1, Jeffrey Sunshine1, Mark Griswold1 1Case Western Reserve University, Cleveland, USA

GRAPPA and TWIST were combined to a novel 4D dynamic high resolution contrast enhanced magnetic resonance angiography allowing for the first time to image the entire cerebral vasculature during a contrast bolus passage at near isotropic resolution. In 25 neurological patients this technique showed improved small vessel depiction over the current clinical standard TOF-MRA. It also delivered superior results in patients prone to motion and those with metal artifacts. The simplicity of data acquisition makes bolus timing unnecessary, readily shows all phases of anatomy from arteries through veins, and can strongly impact imaging of patient cerebral vasculature in daily practice.

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14:30 3418. Phase Contrast Flow Quantification of Carotico-Vertebral Blood Flow at 3.0T in Patients with Angiographically Normal Vessels Fatemeh Barkhordarian1, Derek G. Lohan1, Aparna Singhal1, reza habibi1, Abbas Nasiraei-Moghaddam1, Roya Saleh1, Pablo Villablanca1, Paul J. Finn1 1UCLA, Los Angeles, USA

Precise quantification of cerebral blood volume flow with combined morphological and hemodynamic data has many potential applications in neurovascular imaging.We sought to evaluate the normal ranges of caroticovertebral blood flow in a large number of patients with normal MR Angiography using a high temporal resolution protocol at 3.0 Tesla,thus providing reference values for future access and suggest that there is considerable variability in ‘normal’ cerebral blood flow in the absence of strong relationship with patient age or gender.

15:00 3419. Using Vessel Encoded Arterial Spin Labeling Technique to Evaluate Cerebral Blood Flow Territories in Volunteers and Carotid Occlusion Patients WU Bing1, 2, GUO Jia3, Wong Eric C. 4, WANG Xiaoying1, 3, ZHANG Jue3, JIANG Xue-xiang1, FANG Jing3 1Peking University 1st Hospital, Beijing, People's Republic of China; 2Peking University , Beijing, People's Republic of China; 3Peking University, Beijing, People's Republic of China; 4University of California,San Diego, La Jolla, USA

We present a new method, vessel encoded imaging(VEI), for evaluating the individual brain-feeding arteries of healthy volunteers and carotid occlusion patients quantitatively and qualitatively. VEI can measure elective cerebral blood flow (sCBF) mapping of the flow territories of the left and right internal carotid arteries and vertebrobasilar arteries, which could aid in the planning and staging of interventions such as carotid endarterectomy, stenting, or bypass.

13:30 3420. Non-Contrast MR Angiography with Multiple Inversion Pulses: Separation of Arteries from Veins with Flexible Inversion Time Naoyuki Takei1, Mitsuharu Miyoshi1, Tetsuji Tsukamoto1 1GE Yokogawa Medical Systems.Ltd, Hino, Japan

Selective inversion recovery pulse (SIR) has been used for non-contrast agent MR angiography. However in-flow time is restricted to the inversion time (TI). Aim of our study is to enhance depiction of arteries with longer in-flow time over TI for background suppression. At first SlR is applied. After a waiting time, non-selective inversion pulse follows. The multiple inversion pulses offer a longer in-flow time. Separation of arteries from veins was successfully performed with TI=1300 to 2000 ms in volunteer scans. This method provides a longer in-flow time of arteries than the T1 value of vein and improved depiction of arteries.

14:00 3421. Carotid Plaque Imaging with BLADE Masahiro Ida1, Kennichi Motoyoshi1, Hiroyuki Fukuyama1, Hisashi Yoshizawa1, Naoya Yorozu1, Keiko Hino1 1Tokyo Metroplolitan Ebara Hospital, Oota-ku, Japan

BLADE-T2WI and T1WI are feasible for detecting not only atherosclerotic carotid plaque but also the neighboringturbulent flow, which is a risk factor of the intimal injury. Multi-slice BLADE sequences are useful methods and the initial sequences of choice for screening of carotid plaque and its risk factor.BLADE dark blood (DB) sequences with cardiac gating are the best-preferred methods for precise evaluation of anatomical details and plaque contents. When multi-slice BLADE T2WI and T1WI show positive findings, single-slice BLADE-DB sequences with cardiac gating should be added to access carotid plaque precisely.

14:30 3422. Assessment of Intracranial Aneurysm Thrombosis with Patient-Specific Computational Models Based on MRI Data Vitaliy L. Rayz1, Loic Boussel1, 2, Joseph R. Leach1, Gabriel Acevedo-Bolton1, Randall T. Higashida3, Michael T. Lawton3, Alastair J. Martin3, William L. Young3, David Saloner, 13 1VA Medical Center, San Francisco, USA; 2Créatis-LRMN (LB, PCD), UMR CNRS 5515, INSERM U630, Lyon, France; 3University of California San Francisco, USA

MR imaging and velocimetry were used to predict the flow in patients who had thrombus-free vessels, and then proceeded to develop intra-aneurysmal thrombus. High resolution, contrast-enhanced MRA images were used to obtain patient-specific lumenal geometries. Images obtained at baseline and at follow up studies were co-registered to determine regions of thrombus formation. Computational Fluid Dynamics (CFD) models were constructed using the baseline geometries and inlet conditions. Results indicate a strong similarity between the slow flow regions predicted in CFD simulations and the regions filled with thrombus in vivo. This study indicates computational models may offer guidance for cerebral aneurysms treatment.

15:00 3423. Evaluation of Unruptured Intracranial Aneurysms with 3 Tesla 3D Time-Of-Flight MR Angiography : Comparison of 64-Channel Multidetector Row CT Angiography Yoshiyasu Hiratsuka1, Hitoshi Miki1, Keiichi Kikuchi1, Ikuko Kiriyama1, Teruhito Mochizuki1, Shizue Takahashi2, Ichiro Matsubara3, Kazuhiko Sadamoto3 1Ehime University School of Medicine, Toon, Japan; 2Ehime National Hospital, Toon, Japan; 3Washo-kai Sadamoto Hospital, Matsuyama, Japan

The purpose of this study was to compare 3D time-of-flight magnetic resonance angiography (3D TOF MRA) at 3 tesla (T) and 64-channnel multidetector row computed tomographic angiography (64-MDCTA) in the detection of angiographically proved unruptured intracranial aneurysms with a blind reader study.3 T 3D TOF MRA and 64-MDCTA are excellent examinations with high diagnostic accuracy for detection of unruptured intracranial aneurysms. These two modalities have the almost same ability for evaluation of intracranial aneurysms, and there is no significant difference. 3D TOF MRA is free from the risks concerning the use of contrast media or the exposure of x-ray, and widely applied for the screening examination of evaluation of intracranial aneurysms. From this results, with regard to the evaluation of intracranial aneurysms, improvement of diagnosis on 3 T TOF MRA will reduce the necessity for the additional CTA examination after MRA.

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13:30 3424. Can the Hemodynamic Geographical Factors Be the Cause of Concurrent Cavernous Malformation in the Cerebral Developmental Venous Anomaly? Yoo Jin Hong1, Tae-Sub Chung2, Kwon Duk Seo1, Sang Hyun Suh2, Kyung Yul Lee2 1Yongdong Severance Hospital,Yonsei University College of Medicine, Seoul, Republic of Korea; 2Yongdong Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea

Hemodynamic disturbance within the territory DVA by geographical factors may be a key factor in leading to cascade of events and subsequent development of a CM and 3.0 T high resolution MR units would be helpful to depict the find morphological detail of small vascular structures of DVA and CM and find such hemodynamic geographical factors.

14:00 3425. Flow-Sensitive Black Blood Imaging for Evaluating Vascular Malformations Takao Kodama1, Takanori Yano2, Shozo Tamura1, Yoshio Machida3, Tokunori Kimura3 1Faculty of Medicine, University of Miyazaki, Miyazaki, Japan; 2Faculty of Medicine, University of Miyazaki,, Miyazaki, Japan; 3Toshiba Medical Systems, Otawara, Japan

The Purpose of this study was to estimate the utility of the newly developed flow-sensitive black blood (FS-BB) sequence in the evaluation of the vascular malformations. On the FS-BB imaging, the vascular structures can be enhanced by applying the dephaging gradient to susceptibility-weighted imaging. All venous malformations were more clearly visualized on FS-BB than flow-insensitive black blood (FI-BB) images. On FS-BB images, all of arteries, niduses, veins, and hemorrhagic lesions appeared as gblackh structures in patients with arteriovenous malformation or dural arteriovenous fistula. FS-BB can be a feasible tool for evaluating vascular malformations.

14:30 3426. Imaging the Cerebral Venous Sinuses’ Puls Curve by Ultrafast Dynamic BOLD MRI Jan-Hendrik Buhk1, 2, Gunther Schütze1, Kai Kallenberg1, Gunther Helms1, Jürgen Baudewig1, Andreas Wellmer1, Michael Knauth1, Peter Dechent1 1University Göttingen, Göttingen, Germany

Fast and dynamic imaging of the cerebral venous sinuses’ puls curve could be a useful additional tool in clinical diagnostic imaging of diseases like cerebral sinus thrombosis. We present a pilot study to evaluate the possibilities of fast dynamic single-slice blood oxygen level dependent (BOLD) imaging in displaying rhythmic signal changes in the cerebral venous sinuses. These findings highly correlate with reference techniques like phase contrast angiography (PCA) and duplex sonography, therefore the demonstration of an intracranial venous pulse curve is feasible.

15:00 3427. Quantification of Cerebrovascular Reactivity by BOLD MRI and Correlation with Conventional Angiography in Patients with Moyamoya Disease Chris Heyn1, Julien Poublanc1, Jay S. Han2, Danny M. Mandell1, Jeff A. Stainsby3, Adrian P. Crawley1, Karel G. terBrugge1, Joseph A. Fisher2, David J. Mikulis1 1Toronto Western Hospital, Toronto, Canada; 2Toronto General Hospital, Toronto, Canada; 3GE Healthcare, Toronto, Canada

Moyamoya disease (MMD) is a vasculopathy characterized by progressive narrowing of proximal circle of Willis vessels and the formation of secondary collaterals. As the disease advances, adequate perfusion distal to vessel stenoses is lost when compensatory vasodilatation reaches a maximum. Further increases in vascular resistance ultimately leads to tissue oligemia and possible ischemia. Recently, we have developed a methodology for rapidly and accurately controlling end tidal PCO2 utilizing a CO2 rebreathing device. Using this technique with blood oxygen level dependent (BOLD) MRI, a quantitative map of cerebrovascular reactivity (CVR), defined as the change in MR signal per mmHg change in end tidal PCO2, can be generated for patients with MMD. In the present work, we apply BOLD CVR to patients with MMD and correlate the quantitative high resolution maps with angiographic features found on conventional vessel angiography. Reduction in mean CVR correlates well with the degree of MMD disease measured by modified Suzuki score or the presence of moya vessels and pial collaterals as visualized by conventional angiography.

Multiple Sclerosis: Disease Severity, Progression Hall D Tuesday 13:30-15:30

13:30 3428. The Relationship Between Brain NAWM and GM Damage is Localised to Specific Clinically Relevant Regions in Early PPMS Benedetta Bodini1, 2, Zhaleh Khaleeli1, Mara Cercignani1, 3, David H. Miller1, Alan J. Thompson1, Olga Ciccarelli1 1University College of London, London, UK; 2Sapienza, Università di Roma, Roma, Italy; 3Fondazione Santa Lucia, Roma, Italy

We used tract based spatial statistics and voxel based morphometry to assess separately white and grey matter abnormalities in patients with early primary progressive MS to clarify in vivo the relationship between the pathological processes occurring in the two compartments. We found 11 areas of anatomical correspondence between white and grey matter damage; however, when investigating the presence of a quantitative correlation, this was only found in 4 clinically eloquent regions. In such regions, we found that grey and white matter damage contribute to disability independently from each other.

14:00 3429. MRI Correlates of Hippocampal Demyelination in Multiple Sclerosis Brains Elizabeth Fisher1, Ansi Chang1, Kunio Nakamura1, Richard A. Rudick1, Bruce D. Trapp1 1Cleveland Clinic, Cleveland, Ohio, USA

Histopathologic studies have demonstrated extensive demyelination in hippocampus in MS brains, but MRI correlates have not been defined. To investigate whether hippocampal pathology can be detected using common MRI sequences, we compared imaging characteristics in normally myelinated (n=4) and severely demyelinated (n=5) hippocampi obtained from MS patients post-mortem. MRIs were acquired in situ, prior to tissue fixation. Mean T2, T1, and MTR contrast ratios were not different, but MTR histograms from demyelinated hippocampi were shifted downward. These data suggest that MTR histogram peak position may a marker of hippocampal pathology in MS patients.

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14:30 3430. Cognitive Dysfunction in Benign MS is Associated with Increased Severity of Corpus Callosum Damage Elisabetta Pagani1, Sarlota Mesaros1, Marco Rovaris1, Domenico Caputo2, Angelo Ghezzi3, Ruggero Capra4, Antonio Bertolotto5, Gianna Riccitelli1, Vittorio Martinelli1, Giancarlo Comi1, Massimo Filippi1 1Scientific Institute and University Ospedale San Raffaele, Milan, Italy; 2Scientific Institute Don Gnocchi, Milan, Italy; 3Ospedale di Gallarate, Gallarate, Italy; 4Spedali Civili, Brescia, Italy; 5Ospedale San Luigi, Orbassano, Italy

In this study we wished to investigate the relationship between the cognitive profile of benign multiple sclerosis (BMS) patients and the extent of tissue damage in the corpus callosum (CC). A method, which enables us to track and investigate atrophy and tissue damage of the CC was used in 54 BMS patients and correlations with neuropsychological tests (NPT) exploring memory, attention and frontal lobe cognitive domains were investigated. We found that cognitive dysfunction is associated with an increased severity of CC damage, in terms of both discrete lesions and fiber bundle disruption.

15:00 3431. Changes in Blood-Brain Barrier Permeability and Blood Volume During MS Lesion Development and Evolution Jeffrey Moses Njus1, Xin Li1, 2, Charles S. Springer1, 2, Maria Taylor3, Tiana Greisel1, Frank W. Telang2, Patricia K. Coyle3, William D. Rooney1, 2 1Oregon Health and Science University, Portland, Oregon, USA; 2Brookhaven National Laboratory, Upton, USA; 3Stony Brook University, Stony Brook, USA

Brain 1H2O R1 ≡ T1-1] data were collected from 12 healthy controls and 16 MS subjects at 4 T before and after gadolinium contrast reagent administration.

Normal appearing white and gray matter ROIs were selected and Ktrans and mole fraction blood water (pb) values were compared between control and MS groups. These were monitored during the development and evolution of MS lesions.

13:30 3432. Correlation of Regional Brain Tissue Loss and Disease Severity in Relapsing-Remitting Multiple Sclerosis: A VBM Study in a Large Patient Population Anna Prinster1, Mario Quarantelli1, 2, Roberta Lanzillo3, Carmine Mollica2, Petronilla Salvatore2, Giuseppe Orefice2, Bruno Alfano1, Vincenzo Brescia Morra2, Arturo Brunetti, 12, Marco Salvatore2 1National Research Council, Naples, Italy; 2University "Federico II", Naples, Italy; 3Hermitage Hospital IDC, Naples, Italy

Possible correlations between brain tissue loss and clinical severity were investigated using optimized VBM in 128 RR MS patients, showing a preferential correlation with EDSS of GM volume reduction in the primary motor cortex bilaterally, with an associated preferential right-sided tWM loss in subcortical regions stemming from the rolandic areas and following the pyramidal tract down to the brainsteam.

14:00 3433. Susceptibility-Weighted MR Imaging of Vascular Distribution in White-Matter MS Lesions Jennifer Elizabeth Dixon1, Emma C. Tallantyre1, Paul S. Morgan1, Matthew J. Brookes1, Nikos Evangelou1, Peter G. Morris1 1The University of Nottingham, Nottingham, UK

The relationship between white-matter MS lesions and parenchymal blood vessels has been found to be predictive of treatment response, and is therefore of considerable clinical interest. Previous in vivo studies have been limited by the inability to view both the lesion and blood vessel on one MR image, resulting in the failure to determine their exact spatial relationship. In this study, we present susceptibility-weighted MR imaging at 7 Tesla as a technique for the identification of both lesions and blood vessels, aiding the study of the perivascular distribution of MS lesions.

14:30 3434. DCE-MRI Ktrans Mapping of MS Lesion Evolution in Individuals Jeffrey Moses Njus1, Xin Li1, 2, Charles S. Springer, Jr. 1, 2, Maria Taylor3, Frank W. Telang2, Patricia K. Coyle3, William D. Rooney1, 2 1Oregon Health and Science University, Portland, Oregon, USA; 2Brookhaven National Laboratory, Upton, USA; 3Stony Brook University, Stony Brook, USA

Transient focal disruption of the blood-brain barrier (BBB) is the most pronounced cerebrovascular abnormality in multiple sclerosis (MS) brain tissue. Though serial MRI studies involving gadolinium (Gd) contrast reagents have provided evidence that BBB permeability compromise is among the earliest expressions of MS pathology detectable by imaging techniques, quantitative BBB permeability changes throughout the course of lesion evolution have not be examined. In this study, we apply pharmacokinetic mapping techniques via dynamic-contrast-enhanced (DCE) MRI as means of investigating quantitative BBB permeability heterogeneity changes in relapsing-remitting MS (RRMS) brain tissue throughout the different phases of lesion development.

15:00 3435. Deep Gray Matter Atrophy as an MRI Metric of Physical and Cognitive Impairment in Patients with Multiple Sclerosis Antonio Gallo1, Iordanis E. Evangelou1, Vasiliki N. Ikonomidou1, Robert L. Kane, Susan K. Stern1, Joan M. Ohayon1, Fredric Cantor1, Henry McFarland1, Francesca Bagnato1 1National Institutes of Health, Bethesda, Maryland, USA

We investigated the role of deep gray matter (dGM) atrophy in determining physical and cognitive impairment in patients with Multiple Sclerosis (MS). Twenty-four MS patients and 24 age-, gender- and education-matched healthy volunteers (HVs) underwent 3T MPRAGE, clinical and an extensive neuropsychological evaluation. dGM structures were segmented using the FreeSurfer software and volumes of both the thalamus (Th-vol) and basal ganglia (BG-vol) were obtained. Th-vol was significantly reduced in MS patients with respect to HVs, whereas differences in BG-vol did not reach statistical significance. Further analysis showed that atrophy of dGM structures correlated well with physical and several cognitive scores.

13:30 3436. Correlating Iron with T2 Signal Intensity in Multiple Sclerosis Lesions Using Susceptibility Weighted Imaging E. Mark Haacke1, Malek Makki1, Yulin Ge2, Megha Maheshwari1, James Garbern1, Omar Khan1, Jiani Hu1, Madesh Selvan1, Latif Zahid1 1Wayne State University, Detroit, Michigan, USA; 2New York University, New York, New York, USA

Susceptibility weighted imaging (SWI) filtered phase data provides a means to monitor changes in iron content from hemosiderin. We used SWI to image multiple sclerosis lesions and compare them to those seen in T2 imaging. We find that the putative iron content associated with SWI phase images correlates negatively with T2 hyperintensities in multiple sclerosis lesions.

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14:00 3437. Automated System for Temporal Tracking of Multiple Sclerosis Lesions Michel Bilello1, Chamith S. Rajapakse1, Neerav Mehta1, Ragini Verma1, Elias R. Melhem1 1University of Pennsylvania, Philadelphia, USA

Interpretation of MRI scans of multiple sclerosis patients can be a very challenging task for the neuroradiologist due to changes in size, shape and position of the lesions. Manual tracking of temporal evolution of lesions is time and labor intensive and prone to inter-rater variability. Some of these limitations and challenges can be overcome by using a standardized automated system presented here. The accuracy and robustness of the predictions given by the automated system was validated with data made available by collaborative MS studies and those generated by a modified protocol.

14:30 3438. Multiparametric MR Analysis of Temporal Evolution of Abnormality in MS Nematollah Batmanghelich1, Xiaoying Wu1, Christos Davatzikos1, Clyde E. Markowitz1, Ragini Verma1 1University of Pennsylvania, Philadelphia, USA

Various modalities, have been used individually to quantify damage in the normal appearing brain tissue(NABT); however, few studies combine these modalities to derive better information about tissue abnormality, with most methods concentrating on lesion segmentation rather than tissue abnormality characterization. We combine several MR modalities into a probabilistic pattern classification method to determine a voxel-wise probabilistic tissue abnormality score. This score can then been correlated with clinical and cognitive scores to study temporal WM changes. This method is applicable to studying treatment effects and can help physicians determine the extent of abnormality beyond the conventional visual symptoms like lesions.

15:00 3439. A Voxel-Wise Random Field Theory-Based Magnetization Transfer Approach for Detecting Focal Demyelination and Remyelination in Multiple Sclerosis Michael G. Dwyer1, Milena Stosic1, Sara Hussein1, Arpad Kelemen1, David Wack1, Robert Zivadinov1 1State University of New York at Buffalo, Buffalo, New York, USA

Magentization transfer imaging (MTI) may provide a means for detecting demyelination and remyelination in-vivo in patients with multiple scelrosis. We demonstrate a sensitive and statistically sound technique for identifying and quantifying areas of focal magentization transfer ratio (MTR) via longitudinal MTI. This method is based on random field theory (RFT), and may have significant sensitivity and specificity advantages over whole-brain, region-of-interest, or purely voxel-wise approaches.

13:30 3440. Voxel Based DTI Analysis Predicts Suggestive of MS Track in Clinically Isolated Syndrome Patients Yasheng Chen1, Valerie Jewells1, Silva Markovic-Plese1, Hongtu Zhu1, Diane Armao1, Hongyu An1, Elizabeth Bullitt1, Weili Lin1 1The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA

Patients presenting as clinically isolated syndrome (CIS) were imaged using DTI and were clinically evaluated ~2yrs after the initial DTI scans. Based on the clinical status, patients were divided into two groups: suggestive of multiple sclerosis (CIS-MS) and not suggestive of MS (CIS-NMS). Voxel-based analysis of the baseline DTI revealed that CIS-MS patients demonstrated significantly more severe sub-cortical abnormalities when compared with CIS-NMS patients. Thus, our findings strongly supported that DTI may be a powerful imaging marker to predict CIS patients who may evolve into MS in future, allowing potentially early therapeutic intervention to reverse/retard the disease processes.

14:00 3441. Structural MRI Correlates of Benign Multiple Sclerosis. A Voxel-Based Morphometry Study of Regional Grey Matter Atrophy Elisabetta Pagani1, Sarlota Mesaros1, Marco Rovaris1, Domenico Caputo2, Mauro Zaffaroni3, Ruggero Capra4, Antonio Bertolotto5, Vittorio Martinelli1, Giancarlo Comi1, Massimo Filippi1 1Scientific Institute and University Ospedale San Raffaele, Milan, Italy; 2Scientific Institute Don Gnocchi, Milan, Italy; 3Ospedale di Gallarate, Gallarate, Italy; 4Spedali Civili, Brescia, Italy; 5Ospedale San Luigi, Orbassano, Italy

We used voxel-based morphometry to assess regional grey matter (GM) atrophy changes in 60 patients with benign mulitple sclerosis (BMS), 35 with secondary progressive (SP) MS and 21 controls. Compared to controls, SPMS patients showed a pattern of widespread GM atrophy, while BMS had reduced GM volume in the subcortical and frontoparietal regions. In comparison with BMS patients, those with SPMS had significant GM loss in the both cerebellar hemispheres, as well as in the right nucleus dentatus. Cerebellar atrophy seems to be a major determinant of irreversible locomotor disability in MS.

14:30 3442. Segmentation of 3T Diffusion Tensor Images with Multiple Sclerosis Lesions Mustafa Okan Irfanoglu1, Steffen Sammet1, Regina Maria Koch1, Raghu Machiraju1, Michael V. Knopp1 1The Ohio State University, Columbus, Ohio, USA

Diffusion Tensor Imaging has a significant use in early diagnosis of Multiple Sclerosis (MS). The traditional methods of MS lesion detection are based on building statistical distributions of white matter fractional anisotropy (FA) and diffusivity (ADC) of healthy regions and trying to detect deviations from these distributions. In this study, we propose a novel method for segmenting diffusion tensors, which makes use of the entire tensor information instead of derived scalar fields and use this segmentation approach to detect candidate MS lesions.

15:00 3443. High-Resolution in Vivo Imaging of Cortical Lesions in Multiple Sclerosis: A Comparison of 3T and 7T Jennifer Elizabeth Dixon1, Paul S. Morgan1, Emma C. Tallantyre1, Matthew J. Brookes1, Nikos Evangelou1, Peter G. Morris1 1The University of Nottingham, Nottingham, UK

Post-mortem MS studies have shown significant demyelination of the deep and cortical grey matter (GM), but in vivo study is made difficult due to the insensitivity of MRI to this type of lesion. The spatial resolution and contrast mechanisms available at 7T appears to be advantageous in the detection and delineation of these lesions, suggesting that it will be a useful tool in the study of cortical pathology.

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13:30 3444. 3T Sodium MRI of Patients with Multiple Sclerosis Guillaume Madelin1, Niels Oesingmann2, Sonia Nielles-Vallespin3, Joseph Herbert1, Glyn Johnson1, Matilde Inglese1 1New York University, New York, New York, USA; 2Siemens Medical Solutions, New York, New York, USA; 3AG Siemens Medical Solutions, Erlangen, Germany

Axonal degeneration occurs from the onset of multiple sclerosis (MS) and it is thought to be a significant cause of disability. Several studies have shown that the accumulation of sodium in the axons can promote degeneration. Sodium MRI provides an indicator of cellular and metabolic integrity and has been applied to the study of patients with brain tumors and stroke. The aim of this study was to demonstrate the feasibility of performing sodium MRI of the brain in patients with MS and to report preliminary results of the changes of tissue sodium concentration in MRI-visible lesions and normal-appearing white matter.

14:00 3445. Definition and Classification of Registration Artifact (“Yin Yang” Artifact) on MR Subtraction Imaging in Multiple Sclerosis (MS): A Pilot Study Yang Duan1, 2, Mehu P. Sampat1, Peter G. Hildenbrand1, David F. Tate1, Yi Tang1, Annika M. Berger1, Dominik S. Meier1, Charles R.G. Guttmann R.G Guttmann1 1Brigham and Women’s Hospital Harvard Medical School, Boston, Massachusetts, USA; 2The First Hospital, China Medical School, Shenyang, People's Republic of China

We analyzed YYA based on the underlying registration mechanism, to facilitate in understanding of the their causes and accuracy in interpreting lesion progressions on subtraction images. Dual echo PD/T2 weighted MR images were acquired, co-registered, intensity normalized and subtracted. YYA is a counterpoised increase and decrease of signal changes around lesions on subtraction images. YYA was identified and classified into four subtypes by radiologists according to mis-registration orientation, corresponding to patients’ movement on right-left (I), anterior-posterior (II), cranial-caudal (III) and combined shifting dimension (IV) respectively. Type III and IV occurred more frequent than type II and I.

14:30 3446. Coarseness of MRI Texture in Acute Lesions Relates to Subsequent Recovery Activity in Multiple Sclerosis Yunyan Zhang1, Hongmei Zhu2, Joseph Ross Mitchell1, Luanne M. Metz1 1University of Calgary, Calgary, Canada; 2York University, Toronto, Canada

Texture property in new multiple sclerosis (MS) lesions were quantified on 1.5T T2-weighted MRI 2 months before and 8 months after the appearance of gadolinium-enhancement using the multiscale polar Stockwell transform (PST). Seven/12 lesions were persisting (T2 hyperintensity) and 5/12 were invisible (no hyperintensity) 8 months post-enhancement. Significantly higher coarse texture (low frequency) was observed in the persisting lesions than that in the invisible lesions in the pre-lesional NAWM, during acute phase, and at chronic phase (P<0.05). This preliminary study indicates that the PST analysis may be useful in predicting lesion recovery on conventional T2-weighted MRI in MS.

15:00 3447. Betainterferon Treatment: Absolute Quantification of White Matter Metabolites in Patients with Multiple Sclerosis Olof Dahlqvist Leinhard1, 2, Jacek Jaworski1, Maria Gustavsson1, Anders Tisell1, Dominique Gladigau1, Anne-Marie Landtblom1, Peter Lundberg1 1University of Linkoping, Linkoping, Sweden

Multiple sclerosis can be treated with immunomodulatory drugs that can decrease the number and severity of bouts and also slower disability-progress. The mechanism, however is not fully understood. In order to improve the assessment of changes in the brain metabolome using MRS, a method was developed that allows for absolute quantification of metabolites as NAA, Cho, myo-Ins, Cr, Lac, Glc etc. Proton-MRS spectroscopy was performed before and after more than two years of betainterferon treatment. We report a decrease of NAA, as a marker of neuronal status and an increase of myo-Inositol due to degradation in these treated patients.

Prion Disease & Neurodegenerative Disorders Hall D Tuesday 13:30-15:30

13:30 3448. Cytoarchitecture of Frontal Cerebral Cortex in Variant Creutzfeldt-Jakob Disease: Post Mortem MR Microscopy at 9.4 Tesla Harpreet Hyare1, 2, Po-Wah So2, John S. Thornton1, Caroline Powell1, Harry Parkes1, Durrenajaf Siddique1, Steve Wroe1, Sebastian Brandner1, Tarek Yousry1 1Institute of Neurology, London, UK; 2MRC Clinical Sciences Centre, Hammersmith Hospital, Imperial College London, London, UK

Ex vivo MRM at 9.4T can depict pathology characteristic of vCJD by demonstrating apparent loss of the normal intracortical laminations. These observations will be increasingly relevant as high-field MRI systems with improved spatial resolution enter clinical practice, when in vivo assessment of the cerebral cortex may prove highly beneficial in the diagnosis and monitoring of vCJD

14:00 3449. The Pulvinar Sign in Variant Creutzfeldt-Jakob Disease: Quantitative Diffusion-Weighted Imaging in Vivo at 1.5T and Ex Vivo at 9.4T with Histopathological Correlation Harpreet Hyare1, 2, John S. Thornton1, Durrenajaf Siddique1, Laura Mancini1, Jager Rolf1, Steve Wroe1, Caroline Powell1, Sebastian Brandner1, Po-Wah So2, Tarek Yousry1 1Institute of Neurology, London, UK; 2MRC Clinical Sciences Centre, Hammersmith Hospital, Imperial College London, London, UK

Despite the hyperintensity seen on DWI, in vivo pulvinar ADCs were increased in vCJD compared with controls, suggesting that this pulvinar hyperintensity is a T2 effect, while histological analysis demonstrated that gliosis in the pulvinar is likely to be the pathological substrate. Correlations between ex vivo FA and histopathological scores were negative for spongiosis and positive for gliosis, suggesting the latter may reinforce the directional organization of the neuropil. Future studies will determine the value of in vivo DTI metrics as pathologically specific indices of disease severity in vCJD.

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14:30 3450. Influence of B Factor on ADC Sensitivity in Creutzfeldt-Jakob Disease Hedok Lee1, Andrew Degnan1, Chen Hoffmann2, Peter Barbara Kingsley3, 4, Isak Prohovnik1 1Mount Sinai School of Medicine, New York, New York, USA; 2Chaim Sheba Medical Center, Israel; 3North Shore University Hospital, Manhasset, USA; 4New York University School of Medicine, New York, New York, USA

In this first rigorous test of the influence of b factor (1000 Vs 2000 s/mm^2) on the sensitivity of DWI to detect Creutzfeldt-Jakob disease, we scanned 13 CJD patients and 15 healthy relatives at both b levels, computed ADC, and quantitatively compared the results both in voxel-level (SPM5) and VOI (FSL) analyses. The b=2000 data showed greater ADC reductions in patients compared to controls, and larger areas of statistically significant ADC reductions, especially in the thalamus and caudate nucleus. The findings demonstrate that MRI can be more sensitive to reduced diffusivity in basal ganglia at b=2000 than at b=1000.

15:00 3451. Global and Tissue-Specific Cerebral Magnetisation Transfer Ratios in Inherited Prion Disease: Correlation with Disease Severity Durrenajaf Siddique1, 2, S Wroe1, 2, H Hyare2, T Webb1, 2, R Macfarlane1, 2, J Collinge1, 2, S Walker3, T Yousry4, JS Thornton4 1National Prion Clinic, National Hospital for Neurology and Neurosurgery, London, UK; 2Institute of Neurology, Queen Square, London, UK; 3Medical Research Council Clinical Trials Unit, London, UK; 4Lysholm Department of Neuroradiology, National Hospital for Neurology and Neurosurgery, London, UK

Inherited prion diseases (IPD) are progressive neurodegenerative disorders, conventional MR neuroimaging often being unremarkable. Global and tissue-specific cerebral magnetisation transfer ratios (MTRs) were investigated in twenty-three patients, using MTR and conventional imaging. Whole-brain, white and grey matter histogram mean, peak height, peak location, and MTR at the 25th, 50th and 75th percentile were calculated, and patients evaluated using videoed and non-videoed neurological rating scales. Significant (p<0.01) bivariate Spearman rank correlations were found between multiple histogram parameters and clinical scores, with a single pathological conventional MR. MTR histogram measures may provide valuable indices of IPD disease severity for future therapeutic trials.

13:30 3452. Postmortem Magnetisation Transfer Ratio in Human Prion Diseases at 1.5T and Histopathological Correlation at 9.4T Durrenajaf Siddique1, Harpreet Hyare1, Steve Wroe1, John Collinge1, Caroline Powell1, Sebastian Brandner1, Po-Wah So2, Tarek Yousry1, John S. Thornton1 1Institute of Neurology, London, UK; 2MRC Clinical Sciences Centre, Hammersmith Hospital, Imperial College London, London, UK

We have shown for the first time that, ex vivo, MTR is lower in cortical and deep grey matter, but not white matter, in patients with prion disease compared to controls, presumably reflecting an increase in the fraction of free-to-bound water. In targeted high-resolution MTR measurements we have also shown that cortical MTR correlated negatively with increasing spongiosis, a histopathological feature unique to prion disease. The major advantage of post mortem quantitative MRI is the possibility of direct comparison with histology; our results suggest that MTR may provide a useful in vivo surrogate marker for pathology in human prion disease.

14:00 3453. Abnormal Connectivity Pattern of Fronto-Striatal-Thalamic Circuits of Patients with Tourette Syndrome Based on Probabilistic Tractography Rajkumar Munian Govindan1, Malek Makki1, Michael Behen1, Harry T. Chugani1 1Wayne State University, Detroit, Michigan, USA

Volumetric and functional imaging studies of individuals with Tourette Syndrome (TS) have revealed regional abnormalities typically in structures comprising the fronto-striato-thalamic circuit. However, few studies have evaluated connectivity between the components of this circuit. With diffusion tensor imaging (DTI) and probabilisitic tractography, it is now possible to evaluate white matter integrity. We used DTI tractography to evaluate fronto-striatal and fronto-thalamic connectivity in children with TS as compared to age and gender matched healthy controls. Results showed decreased connectivity in fronto-striatal and fronto-thalamic pathways of TS group, which provides further support for the involvement of the fronto-striato-thalamic circuit in TS.

14:30 3454. Combined 31P and 1H-MRS Study on Brain Energy Metabolism in Progressive Supranuclear Palsy (PSP) Ulrich Pilatus1, Maria Stamelou, Jörg Magerkurth1, P Niklowitz, A Reuss, K M. Eggert, C Schade-Brittinger, W Oertel, Heiner Lanfermann1, G U. Höglinger 1Johann Wolfgang Goethe-Universität, Frankfurt, Germany

Progressive Supranuclear Palsy (PSP) is a sporadic neurodegenerative disorder. In vivo MRS using either 31P or 1H nuclei disclosed significant metabolic differences between patients and age-matched normal controls. This study was aimed at exploiting the full potential of combined 31P and 1H MRS to thoroughly specify parameters for energy metabolism and neuronal damage. No significant differences were detected for 1H detectable metabolites total creatine (tCr) and N-acetylaspartate (tNAA). However, 31P MRS showed a significant decrease of inorganic phosphate (Pi), phosphocreatine (PCr), and ATP in the basal ganglia while in the occipital cortex only ATP was reduced. Lactate was never detected in controls but in approximately 20% of the patients. Calculation of ADP and the phosphorylation potential (PP) using standard equilibrium constant for creatine kinase yielded no differences between patients and controls. This indicates that reduced mitochondrial activity is compensated by reduction of ATP and inorganic phosphate leaving the PP constant, which may account for the rather mild decrease in tNAA. The decrease of phosphometabolites like ATP and Pi should be a marker of the severity of the disease and potential effects of treatment.

15:00 3455. Adults with Significant Childhood Lead Exposure Evaluated with Proton MR Spectroscopy Kim M. Cecil1, Kim N. Dietrich2, Mekibib Altaye1, John C. Egelhoff1, Stephanie D. Wessel2, Bruce P. Lanphear1 1Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA; 2University of Cincinnati, Cincinnati, Ohio, USA

We hypothesized that adults with childhood lead exposure would demonstrate evidence of irreversibly altered neural metabolism. Participants (N=159) of a longitudinal birth cohort studying the effects of lead exposure completed a quantitative, short echo spectroscopy protocol evaluating seven brain regions. Higher mean childhood blood lead levels were associated with reduced metabolite concentrations upon adjusting for age at time of imaging and full scale intelligence quotient. Gray matter reductions of N-acetyl aspartate are consistent with the concept that sustained childhood lead exposure results an irreversible, pattern of injury consistent with an insult from childhood. White matter choline changes suggest an alteration to the myelin structure. These neural alterations may be responsible for the cognitive and behavioral changes attributed to lead exposure.

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Pediatric Brain: DTI, Structural Hall D Tuesday 13:30-15:30

13:30 3456. Application of a Fast High Resolution Whole Brain MRI for Segmentation Ying Wu1, 2, Dunkle Eugene1, Andres Carrillo1, Ann Ragin2, Robert Edelman1, 2 1Evanston Northwestern Healthcare, Evanston, Illinois, USA; 2Northwestern University, Chicago, Illinois, USA

MRI segmentation and visualization have gained increasing importance both in research and clinical applications. The conventional MR sequence, FSPGR (or MP-RAGE), has been widely utilized in MR segmentation and in clinical fMRI because its contrast behavior is suitable for segmentation and this sequence can provide thin slice whole brain coverage. In this investigation, we present a fast whole brain high resolution MR technique, EZ Step (EZ). Images generated with the sub-milliliter isotropic EZ Step sequence have similar GM/WM contrast behavior as FSPGR. Available automated segmentation utilities, such as FSL and Freesurfer, can be adapted for EZ. Moreover, EZ has higher CNR than FSPGR in basal ganglia and other clinically significant regions of interest.EZ can also be used to derive superior quality brain volume rendering for fMRI applications, while reducing data acquisition scan time of current clinical routines by 40%.

14:00 3457. Regionally Specific Cortical Thinning in Paediatric Sickle Cell Disease Richard Alan Jones1, 2, Gregory Kirk3, Michael Ryan Haynes4, Susan Palasis5, Clark Brown6 1Children's Healthcare of Atlanta, Atlanta, Georgia, USA; 2Emory University, Atlanta, Georgia, USA; 3Children's Healthcare of Atlanta, Atlanta, USA; 4Georgia Institute of Technology, Atlanta, USA; 5Children's healthcare of Atlanta, Atlanta, USA; 6Children's Helathcare of Atlanta, Atlanta, USA

Cortical thickness was compared in control and sickle cell paediatric subjects using Freesurfer. The groups were split into two components by age; The first group consisted of all subjects< 12 years of age, and the second group all subjects >=12 years of age. Separate group analyses were performed on each of the two groups. In the younger group relatively few differences were found, while in the older group more extensive areas of bilateral thinning were found in the sickle cell subjects, suggesting that their gray matter is abnormal and that the amount of thinning is age dependent.

14:30 3458. Treatment-Induced Plasticity in Central Motor Pathways in Cerebral Palsy: Diffusion Tensor Imaging Rakesh K. Gupta1, Richa Trivedi1, Vipul Shah, Mukesh Tripathi1, Ram KS Rathore2, Manoj Kumar1, Ponnada A. Narayana3 1Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India; 2Indian Institute of Technology, Kanpur, India; 3University of Texas Medical School at Houston, Houston, USA

Serial diffusion tensor imaging (DTI) was performed on eight pediatric patients with cerebral palsy (CP) at the time of diagnosis and after 6 months of botulinum treatment followed by intensive physiotherapy. Region of interests were placed on corticospinal tracts at the level of corona radiate (CR), posterior limb of internal capsule (PLIC), mid brain (MB), pons, and medulla in patients as well as controls. On 6 month follow-up significantly increased FA values were observed in CST at the level of CR, PLIC, and MB compared to baseline study. The observed increase in FA along with improved clinical motor score suggests plasticity of the central motor pathway following the combined therapy.

15:00 3459. Correlation of Brain Diffusion Tensor Imaging Metrics with Cognitive Functions in Patients of Spina Bifida Cystica Manoj Kumar1, Rakesh Kumar Gupta1, Mazhar Husain2, Sanjay Behari1, Gyanendra K. Malik2, S N. Kureel2, Richa Trivedi1, Ram Kishore Singh Rathore3 1Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India; 2CSMM University, Lucknow, India; 3Indian Institute of Technology, Kanpur, India

Neural tube defect during early pregnancy affects the normal brain development and leads to deficits in cognitive functions and memory. DTI and battery of neuropsychological test (NPT) were performed in 19 SBC patients and controls. ROIs were placed in different region of the brain including deep gray matter [caudate nuclei (CN), thalamus (Th) and putamen (P)] and white matter corticospinal tracts (CST), and cingulum (Cing), fornix, genu and splenium (Spl) in SBC patients as well as controls. The spearman rank correlations between FA, MD and NPT scores were performed in patients and controls. Our observations demonstrated that significant correlation between FA and MD values with FCT score in genu of CC, and significant correlation between FA values in cingulum and NCT B scores which reflects the deficits in learning, memory and timing functions. The FA values in CST are correlated with PAT scores suggesting the deficits in sensory and motor functions.

13:30 3460. Temporal Brain White Matter Maturation in Spina Bifida Cystica (SBC) with Diffusion Tensor Imaging Manoj Kumar1, Rakesh K. Gupta1, Richa Trivedi1, Mazhar Husain2, Sanjay Behari1, Gyanendra K. Malik2, S N. Kureel2, Ram KS Rathore3, Ponnada A. Narayana4 1Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India; 2Chhatrapati Sahuji Maharaj Medical University, India; 3Indian Institute of Technology, Kanpur, India; 4University of Texas Medical School at Houston, Houston, USA

DTI was performed in 23 SBC patients along with 33 age/sex matched controls. ROI were placed in corpus callosum [genu and splenium (Spl)], internal capsule [anterior limb of internal capsule (ALIC), posterior limb of internal capsule (PLIC)], periventricular WM [frontal white matter (FWM), occipital white matter (OWM)] and corticospinal tracts (CST) at the level of pons in SBC patient as well as controls. Different pattern of FA changes in major WM tracts in SBC patients compared to controls demonstrate that the pattern of brain WM in SBC is different from normal development. In SBC patient’s significant reorganization was observed at structural and functional levels during the development.

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MRI: ENT Imaging Hall D Wednesday 13:30-15:30

13:30 3461. Average Arterial Input Function and Quantitative Dynamic Contrast Enhanced (DCE)-MRI of Nodal Metastases in the Neck Amita Shukla-Dave1, Nancy Lee1, Hilda Stambuk1, Ya Wang1, Wei Huang1, Jason A. Koutcher1 1Memorial Sloan-Kettering Cancer Center, New York, USA

Nine patients with nodal metastases in the neck underwent dynamic contrast enhanced MRI (DCE-MRI) studies on a 1.5T clinical MRI scanner. Reliable Individual Arterial Input Function AIF (Ind-AIF) were obtained from all the patients and an average-AIF (Avg-AIF) was calculated. No statistical differences were seen in pharmacokinetic parameters obtained with Ind-Avg and Avg-AIF. The present study builds Avg-AIF in patients with nodal disease in the neck which may be useful in large patient population studies, e. g. in clinical trials to examine the effects of drugs on Ktrans and ve or in situations where Ind-AIF cannot be obtained.

14:00 3462. Perfusion Characteristics of Radiation-Induced Parotitis: Quantitative Evaluation with Dynamic Contrast-Enhanced MRI Hua-San Liu1, 2, Chun-Jung Juan2, Hsiao-Wen Chung1, Cheng-Yu Chen2, Yee-Min Jen2, Chao-Ying Wang1, 2, Chun-Jen Hsueh2, Chung-Ping Lo2, Guo-Shu Huang2 1National Taiwan University, Taipei, Taiwan; 2Tri-Service General Hospital, Taipei, Taiwan

Radiation-induced parotid gland injury degrades the life quality of patients who ever receive radiotherapy for treating head and neck cancer. Conventional MR imaging of the irradiated parotid glands only shows intense parotid enhancement. Applying the non-linear least square curve fitting algorithm to the Brix pharmacokinetic model, the perfusion parameters of the irradiated parotid glands were quantified. The irradiated parotid glands showed significantly lower Kel (P < 0.0005), marginally lower k21 (P < 0.05) and unaltered A (P = 0.26) compared with non-irradiated ones, suggestive of gradual and prolonged accumulation and delayed wash-out of contrast agent in the irradiated glands rather than increased vascular permeability.

14:30 3463. Comparison of Diagnostic Performance Between MRI Including Diffusion-Weighted Imaging and FDG-PET/CT in Patients with Head and Neck Cancer Yuji Nakamoto1, Tomohisa Okada1, Yasuyo Hamanaka2, Kohei Hayashida2, Kaori Togashi1 1Kyoto University Hospital, Kyoto, Japan; 2Takeda Oncologic Positron Imaging Center, Kyoto, Japan

We have compared the diagnostic performance of MRI including diffusion-weighted imaging and FDG-PET/CT in patients with head and neck cancer. For detecting primary tumors or metastatic cervical lymph nodes, the patient-based sensitivity and specificity of MRI were comparable with those of FDG-PET/CT.

15:00 3464. Therapeutic Response Assessment Using Dynamic Contrast-Enhanced MR Imaging in Patients with Differentiated Thyroid Carcinoma: An Initial Study at 3T Jiachao Liang1, Steffen Sammet1, Xingyu Yang1, Guang Jia1, Zarine Shah1, Regina Koch1, Manisha Shah1, Michael V. Knopp1 1The Ohio State University, Columbus, Ohio, USA

Therapy monitoring of differentiated thyroid carcinoma using DCE-MRI at 3T provides a capability for evaluating the biologic therapeutic responses by a clinically readily available approach.

13:30 3465. Monitoring Response to Chemoradiation Therapy of Squamous Cell Carcinomas of the Head and Neck Using Diffusion Weighted MRI Sungheon Kim1, Laurie A. Loevner1, Harry Quon1, Eric J. Sherman1, Gregory S. Weinstein1, Harish Poptani1 1University of Pennsylvania, Philadelphia, USA

The purpose of this study was to investigate the feasibility of using apparent diffusion coefficient (ADC) for early detection of treatment response in squamous cell carcinomas of the head and neck (HNSCC). DW-MRI studies were performed with 32 patients before, during, and after the end of treatment. Pre-treatment ADC of complete responders (CR) was significantly lower than that of partial responders (PR). A significant increase in ADC was observed in the CR group within one week of treatment and remained high until the end of the treatment. These results suggest that ADC can be used as a predictive marker for therapeutic response in HNSCC.

14:00 3466. Monitoring Therapeutic Effect of Cetuximab in the Treatment of Nasopharyngeal Carcinoma by DCE-MRI Francis Kar Ho Lee1, Brigitte Ma1, David Ka Wai Yeung1, Ann Dorothy King1 1the Chinese University of Hong Kong, Hong Kong, People's Republic of China

Dynamic contrasted enhanced MRI is becoming a popular technique to evaluate the therapeutic effect of anti-angiogenic and anti-vascular drugs for the treatment of cancers. The potential of the technique to predict treatment outcome is attractive as it can provide valuable information for treatment planning. In this study, we attempted to use this technique to monitor the therapeutic effect of cetuximab, an epidermal growth factor receptor (EGFR) inhibitor, in the treatment of nasopharyngeal carcinoma (NPC). The effect of this drug in combination with chemotherapy for NPC has been published, while this report describes the preliminary attempt to examine the potential of the DCE technique in the early detection of drug response.

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14:30 3467. Serial MRI Study of Delayed Brain Injury Induced by Radiotherapy Treatment for Nasopharyngeal Carcinoma Yi Xiang Wang1, H Zhou2, 3, A D. King2, J Abrigo2, Y L. Chan2, D K. Yeung2 1The Chinese University of Hong Kong, Prince of Wales Hospital , Shatin, People's Republic of China; 2The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, People's Republic of China; 3First Affiliated Hospital of Zhejiang University, Hangzhou, People's Republic of China

Radiation induced injury (RI) of temporal lobe is a late complication of radiation therapy for nasopharyngeal carcinoma (NPC). This study investigates the temporal changes of RI in the temporal lobe with serial MRI. This is a retrospective study of 77 consecutive patients. These patients had known RI of the temporal lobes due to RT on MR with at least one further follow up MR for analysis. Our results demonstrated that the RI lesions can remain static, increasing, decreasing or resolve, but overall the RI appears to demonstrate an initial developing phase and later resolving phase.

15:00 3468. High Resolution Non-Contrast Lymphangiography of the Head and Neck at 3Tesla Ravi Teja Seethamraju1, Yiu Cho Chung2, Jaeseok Park3, Graham C. Wiggins4, Mukesh G. Harisinghani5, Denise Hinton-Yates4 1Siemens Medical Solutions USA, Inc., Charlestown, Massachusetts, USA; 2Siemens Medical Solutions USA, Inc., Columbus, Ohio, USA; 3Siemens AG., Erlangen, Germany; 4Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, USA; 5Center for Molecular Imaging Research, MGH, Boston, Massachusetts, USA

A state of the art non-contrast T2 weighted TSE 3D sequence for Lymphangiography of the head and neck is presented here. This sequence can detect lymph nodes with 3D isotropic sub-millimeter resolution in a distinct manner. This is a major advantage over traditional 2D TSE methods where the through plane resolution is low thereby increasing the chance of missing small lymph nodes that are less than 5mm. Currently this method can distinctly show all nodes with high contrast immaterial of the nodal status. When combined with nano-particle enhanced contrast agents this techniques has the potential to be sensitive to metastasis.

13:30 3469. Comparison of Duplex Sonography and High Resolution MRI Thorsten Alexander Bley1, 2, Mathias Reinhard1, Carolin Hauenstein1, Michael Markl1, Klaus Warnatz1, Mathias Langer1 1University of Freiburg, Freiburg, Germany; 2University of Wisconsin - Madison, Madison, USA

Giant cell arteritis (GCA) is a chronic vasculitis of large and medium sized arteries. Temporal atery bopsy (TAB) is considered the diagnostic gold standard. Noninvasive diagnosis of GCA is a challenge. The purpose of this study was to to compare the diagnostic performance of high resolution (196µm × 260µm) magnetic resonance imaging (MRI) and color coded duplex sonography (CCDS) in patients with GCA. Sensitivity of MRI (CCDS) compared with TAB was 83% (79%), specificity 71% (59%), NPV 80% (73%) and PPV 75% (67%). Larger trials are warranted to investigate the potential of noninvasive imaging to replace temporal artery biopsy.

14:00 3470. Real Time Sleep MRI and Physiologic Monitoring of Patients with Obstructive Sleep Apnea Andrew B. Holbrook1, 2, Jose Barrera1, Juan M. Santos1, Kim Butts Pauly1, Gerald Popelka1 1Stanford University, Stanford, California , USA

Obstructive sleep apnea (OSA) is a serious and dangerous disorder that could benefit from improved diagnosis with MRI. In this study, ten patients with mild to severe OSA were imaged continuously in real-time in an interventional 0.5T magnet while also monitoring physiological conditions using a WatchPat WP100 OSA testing device. Physiological data were registered to acquired images. Imaging showed locations of airway obstructions, with physiologic data showing signs of possible respiratory events (changing pulse arterial tone amplitude, decreasing oxygen saturation). Such results could be useful in improving patient diagnosis and resultant care.

MRI & MRS of Epilepsy Hall D Wednesday 13:30-15:30

13:30 3471. Distribution of Neurochemical Changes in Narcoleptic Patients with Cataplexy: A Proton MR Spectroscopy Study Caterina Tonon1, Raffaele Lodi1, Giuseppe Plazzi1, Christian Franceschini1, Claudia Testa1, David Neil Manners1, Pasquale Montagna1, Bruno Barbiroli1 1University of Bologna, Bologna, Italy

The pathophysiology of narcolepsy with cataplexy (NC), a rare underdiagnosed sleep disorder, is as yet only partially defined. Investigations using various neuroimaging techniques of brain structures suspected to be involved in sleep/awake regulation have given contradictory results. In the present study of 21 NC patients using 1H-MRS we demonstrated evidence of neuronal loss in the hypothalamus, while no significant biochemical changes were found in the thalamus and the parietal-occipital cortex. Advanced MR techniques may contribute to the clarification of the pathophysiological mechanisms of NC, and hence to the development of targeted pharmacological options.

14:00 3472. Hippocampal Neurotransmitter Imbalance and the Role of GS in Epileptogenesis; a Longitudinal in Vivo MRS and Histochemical Study in a Juvenile Model of Temporal Lobe Epilepsy Pieter van Eijsden1, W Saskia van der Hel1, Ineke W. M. Bos1, Robin A. de Graaf2, Kevin L. Behar2, Onno van Nieuwenhuizen1, Pierre N.E. de Graan1, Kees P.J. Braun1 1University Medical Center Utrecht, Utrecht, Netherlands; 2Yale University, New Haven, USA

Epileptogenesis in temporal lobe epilepsy has been associated with a disturbance of hippocampal glutamatergic and GABAergic neurotransmission. To characterize this disturbance, we combined in vivo MRS with immunohistological methods at two time points during the latent phase of the juvenile lithium pilocarpine rat model. Reductions in NAA and increases in Cho indicate neuronal death and gliosis, which is confirmed by FJ and Vim staining. GABAergic neurons are most affected, leading to a hyperexcitable state. After an initial increase, glutamine normalizes, which is explained by reduced GS immunoreactivity. These findings represent relevant pre-epileptic changes, which serve as markers of imminent epilepsy.

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14:30 3473. Metabolic Connectivity in Controls and Epilepsy Patients Jullie Pan1, Susan Spencer, Ruben I. Kuzniecky2, Dennis Spencer1, Hoby Hetherington1 1Yale University, New Haven, Connecticut, USA; 2New York University, New York, New York, USA

The goal of this study was to evaluate the pattern and extent to which the correlated reductions in NAA from the hippocampus thalamus, putamen and insula define a unique network of impairment which can resolve mesial temporal lobe epilepsy (mTLE) from neocortical epilepsy (NE). MRSI measurements of NAA were acquired from the hippocampus, thalamus, putamen and insula of controls (20), mTLE (27) and NE (18) patients. Significant differences in NAA distributions throughout these neuronal networks were between controls and patients with epilepsy and mTLE and NE patients.

15:00 3474. First Clinical Epilepsy Imaging at 7 Tesla Tobias Breyer1, Jens M. Theysohn2, Stefan Maderwald2, Oliver Kraff2, Marc Ladd2, Friedrich Woermann3, Alois Ebner3, Marc U. Schlamann1, Michael Forsting1, Isabel Wanke1 1Essen University Hospital, Essen, Germany; 2University of Duisburg-Essen, Essen, Germany; 3Bethel Epilepsy Center, Bielefeld, Germany

Even very subtle cortical lesions can cause severe epileptic syndromes. High magnetic field MR-imaging at 7 Tesla therefore promises better signal-to-noise ratio and spatial resolution for improved lesion depiction and subsequently selection of more possible treatment options for affected patients. We investigated -for the first time- patients with known epileptic lesions, either hippocampal sclerosis or focal cortical dysplasia- at 7 Tesla with spin-echo PD-/T2-, T1- as well as T2*-weighted sequences.

13:30 3475. Mapping Hippocampal Activity During Epileptogenesis by Manganese Enhanced Magnetic Resonance Imaging(MEMRI) Ke Fang1, Stefanie Dedeurwaerdere1, Yutang Shen1, Terence J. O'Brien1, Gary F. Egan1 1University of Melbourne, Melbourne, Australia

This longitudinal study aims to characterise the progressive pathological changes in the hippocampus of the post-kainic acid status epilepticus (SE) rat model of temporal lobe epilepsy using MEMRI in vivo. . A progressive increase in signal intensity was found in the hippocampus in the epileptic group compared to the control group , which indicated more neuronal activities in hippocampus in the epilepsy KA model. Early changes in the dentate gyrus also significantly correlated with seizure outcome at a later stage, which may have implications for predicting seizure phenotype.

14:00 3476. Voxel Based Morphometry and Statistical Parametric Mapping of Positron Emission Tomography (SPM-PET) in Patients with Juvenile Myoclonic Epilepsy Compared to Normal Controls Long Vu1, Barbara Swartz2, Mark Mandelkern1, Orhan Nalcioglu1, Min-Ying Su1 1University of California, Irvine, USA; 2Hoag Hospital, Newport Beach, USA

Voxel Based Morphometry (VBM) and Statistical Parametric Mapping of Positron Emission Tomography (SPM-PET) were performed to analyze the differences in brain morphology and PET activity between 18 JME patients and 16 Controls. VBM results showed that JME had more gray matter than Controls in the caudate, cingulate, temporal, and frontal regions. SPM-PET showed that Controls had more glucose uptake than JME in the frontal regions. These findings suggest that VBM and PET may provide complementary structural and functional information. Along with EEG, they might be useful to differentiate between FLE and JME patients.

14:30 3477. Diffusion Tensor Imaging in Lateralising and Localising Epileptogenic Focus in Temporal Lobe Epilepsy with and Without Hippocampal Sclerosis Siew-Min Gan1, Willy Handoko, Soren Christensen, Patricia Desmond, Terence O'brien 1Royal Melbourne Hospital, Univeristy of Melbourne, Melbourne, Australia

Diffusion Tensor Imaging and volumetric changes are compared between Temporal Lobe Epilepsy patients with Hippocampal Sclerosis (HS+ve) and patients with no structural changes on standard MRI (HS-ve). In addition to ADC and FA, the p,q, and L derivatives of the tensor will be explored to quantify anisotropy changes in the hippocampus and the anterior temporal pole gray matter and white matter, with the aim to determine if DTI can localise the epileptogenic region in the subtypes of TLE and whether the DTI changes are independent of the structural changes of hippocampus sclerosis.

15:00 3478. Thalamocortical Atrophy in Patients with Primary Generalized Tonic and Clonic Seizures Boris Christian Bernhardt1, Daniel Rozen2, Linda Horwood2, Andrea Bernasconi1 1Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada; 2Brain Imaging Center, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada

Although previous work in idiopathic generalized epilepsy (IGE) indicates that the thalamocortical circuitry is involved in the generation of the epileptic discharges, the neuropathological substrate of IGE is not fully defined. We measured cortical thickness and calculated the volumes of thalami on high-resolution MRI in IGE patients and healthy controls. In IGE, fronto-centro-parietal areas and the thalamus were bilaterally atrophic. Thickness in the same cortical regions had a high positive correlation with thalamus volumes. Duration of epilepsy negatively affected thalamus volumes and thickness in centro-parieto-occipital areas. Our results therefore demonstrate bilateral and progressive atrophy in thalamocortial networks in IGE.

13:30 3479. Building a 3D Atlas of the Human Hippocampus from Postmortem Magnetic Resonance Imaging Paul A. Yushkevich1, John Pluta1, Brian B. Avants1, David Minkoff1, Stephen Pickup1, Weixia Liu1, John A. Detre1, Murray Grossman1, James C. Gee1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA

High resolution 9.4 Tesla imaging of the human hippocampus in vitro is performed in order to build a three-dimensional atlas of the structure. The atlas will serve as a model of hippocampal substructure for in vivo MRI studies of memory and neurodegenerative disorders.

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Brain Tumor: Perfusion & Diffusion & fMRI Hall D Wednesday 13:30-15:30

14:00 3480. A Comparison of Enhancing Fraction and DCE-MRI Parameters in Glioma of Various Grade Samantha Jane Mills1, Calvin Soh2, Giovanni Buonaccorsi1, James Patrick Bernard O'Connor1, Susan Cheung1, Sha Zhao1, Geoffrey James Martin Parker1, Alan Jackson1 1University of Manchester, Manchester, UK; 2Hope Hospital, Salford, UK

This study compares the proportion of enhancement of a tumour, enhancing fraction, with more complexly derived DCE-MRI parameters of blood volume (vp), contrast transfer coefficient (Ktrans) and the extra-vascular extracellular volume (ve) for a variety of cerebral gliomas of various histological grade. The relationship of these parameters with enhancing fraction is dependent upon tumour grade; in low grade tumours enhancing fraction relates to vp whilst in high grade tumours it relates to Ktrans. This is most likely a result of differences in the integrity of the blood brain barrier seen in tumours of different grade.

14:30 3481. Valuation of Brain Tumours with MRS and PWI-DSC. Use of a Non Parametric Method in the Post Processing of PWI-DSC Salvador Olmos1, Nicolas Nicolas Fayed2, Jorge Humberto Davila 2 1Universidad De Zaragoza, Zaragoza, Spain; 2Hospital Quiron, Zaragoza, Spain

High grade Brain tumors are highly vascularizated. These changes can be easily detected in Perfusion studies; however, as happen in our study sometimes a low vascularity is described. This could be explained by a loose of contrast trough the rupture of the BBB described in high grade tumors. Using a new non parametric method in the post processing of PWI-DCI we look for a better valuation of this phenomenon, that will allows us to have a better tool in the diagnosis of high grade tumors. However, at the moment the best tool for in the diagnosis of brain tumors is MRS.

13:30 3482. Validation of a Standardization Technique for Brain Tumor RCBV Maps and Post-Contrast Anatomic Images Devyani P. Bedekar1, Todd Jensen2, Eric Paulson1, Kathleen M. Schmainda1 1Medical College of WI, Milwaukee, Wisconsin, USA; 2Jensen Bioinformatics, New Berlin, Wisconsin, USA

Relative cerebral blood volume (rCBV) measurements for the same tissue type suffer from interpatient and interstudy variability. As a result, CBV values are commonly normalized to a chosen reference region of interest (ROI) such as white matter (WM). But this technique of normalization is subjective and thus introduces user-dependent variability, and is time-consuming and therefore unlikely to become part of the routine evaluation of longitudinal studies. In this study we demonstrate that standardization of the perfusion values to a consistent scale is at least as good as normalization to a reference ROI. Furthermore, we validate that standardization does not alter the informational content of the image. Thus, standardization enables fast, objective and accurate visual comparison across studies and can be employed with ease in the radiology workflow to longitudinally assess brain tumor progression and response to therapy.

14:00 3483. Comparison of Quantitative Blood Flow Values from DCE- And DSC-Based Perfusion in Glioblastoma Multiforme and Cerebral Tissue Martine Isabella Dujardin1, Steven Sourbron2, Rob Luypaert1, Cristo Chaskis1, Smitha Makkat1, Tadeusz Stadnik1, Johan de Mey1 1UZ Brussel, Brussels, Belgium; 2Klinikum Grosshadern, Munich, Germany

In this study, we compare CBF values in glioblastoma multiforme and contralateral white and grey matter from T1-DCE-based [CBFT1] and T2*-DSC-based [CBFT2*] perfusion, as well as lesion-to-normal-white matter CBF ratios from both techniques. CBFT2* measures were systematically higher compared to CBFT1 and CBF measures from both techniques did not show correlation. DSC-MRI CBF values may be reliable when normalized to a reference tissue type. However, since values of CBFT1 are more in line with the findings for grey and white matter CBF from PET, DCE-based perfusion measures of CBF seem to be preferable in tumor perfusion work-up and follow up.

14:30 3484. A Comparison of DCE-MRI Derived Measure of Extracellular Volume and ADC in Glioblastoma Multiforme Samantha Jane Mills1, Calvin Soh2, Chris Rose1, Susan Cheung1, Sha Zhao1, Geoffrey James Martin Parker1, Alan Jackson1 1University of Manchester, Manchester, UK; 2Hope Hospital, Salford, UK

DCE-MRI provides quantification of the volume of the extravascular extracellular space (ve). An inverse linear relationship between the apparent diffusion coefficient (ADC) and histological measures of cell density has been previously shown in glioma. We proposed that areas of increased cell packing (and low ADC) would have small extracellular volumes (and low ve). No relationship was found between ADC and ve in this study of high grade glioma. This failure of correlation may be due to a number of factors including co-registration issues, partial volume effects, tumour heterogeneity, and abnormalities in cell membrane permeability dictated by the underlying pathology.

15:00 3485. Quantifying the Proportion of Enhancement in Relation to IAUC Thresholds; a Comparison with Other Measures of Enhancement in Adult Gliomas Samantha Jane Mills1, 2, Calvin Soh2, Susan Cheung1, James Patrick Bernard O'Connor1, Sha Zhao1, Geoffrey James Martin Parker1, Alan Jackson1 1University of Manchester, Manchester, UK; 2Hope Hospital, Salford, UK

This study details different methods for assessing the proportion of tumour enhancement in gliomas of various grade, in relation to IAUC values. We describe an optimum technique for separating tumour grade and detail how this compares to other previously described methods of assessing enhancement based upon signal intensity.

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13:30 3486. Longitudinal Assessment of Avastin Therapy Using Biological Response Indicator Perfusion Maps: Predicting Response to Therapy Melissa Lynne Wagner-Schuman1, Devyani Bedekar1, Eric S. Paulson1, Doug E. Prah1, Kathleen M. Schmainda1 1Medical College of Wisconsin, Milwaukee, Wisconsin, USA

The study of tumor angiogenesis for the diagnosis of gliomas has potential benefits in therapeutic management. With the recent clinical trials of anti-angiogenic agents, the necessity for angiogenesis biomarker development has become apparent. In this study we employed a noninvasive imaging technique, DSC-MRI to estimate relative cerebral blood volume and, with the aide of longitudinal registration, created functional cerebral blood volume (fCBV) maps in patients receiving Avastin. The fCBV maps correlated with patient response to treatment giving insight into treatment effectiveness. This study demonstrates longitudinal registration and creation of fCBV maps used to monitor tumor biology and predict therapeutic response.

14:00 3487. "Hot Spot" Analysis for Glioblastoma Multiforme Priscilla Yeo1, Poe J. Chen1, 2, Weiting T. Zhang1, Emmanuelle di Tomaso1, Dan G. Duda1, Rakesh K. Jain1, Tracy T. Batchelor1, Alma G. Sorensen1 1Massachusetts General Hospital, Charlestown, Massachusetts, USA; 2Massachusetts Institute of Technology, Cambridge, Massachusetts, USA

Past studies indicate that there is value in using tumor areas with the highest density of distinctly highlighted microvessels (“hot-spots”) as a prognostic indicator for various cancers. Here, we suggest using a spatial method of locating hot-spots in glioblastoma ROIs to predict survival outcomes of GBM patients.

14:30 3488. Extravascular Enhancement with a Blood-Pool Contrast Agent - A New Class of Contrast in Magnetic Resonance Imaging Marco Essig1, Matthias Voth2, Martin Rohrer2, Frederik Giesel1 1German Cancer Research Center, Heidelberg, Germany; 2Bayer Schering, Berlin, Germany

We present the first study that shows the potential of the protein-binding blood-pool contrast agent gadofosvest trisodium (Vasovist®) for high quality contrast enhanced MR imaging of various cerebral tumors. Even at an early time point a robust enhancement could be observed with a substantially lower amount of Gadolinium-chelate. Furthermore, based on previous experience in animal models one might expect an even more effective contrast at a later time point after administration. Further controlled studies are ongoing to assess the clinical potential of these agents as well as the advantage over the currently established MR contrast agents.

15:00 3489. Detection of Early Response After Radiosurgery for Vestibular Schwannoma Using an Eigen Vector Based Approach Yu-Chun Lin1, 2, Chun-Chieh Wang2, Koon-Kwan Ng2, JiunJie Wang1, 2 1ChangGung University, KweiShan, Taiwan; 2ChangGung Memorial Hospital, KweiShan, Taiwan

This study prospectively examined the changes of directional coherence of vestibular schwannoma (VS) at an acute stage of after stereotactic radiosurgery (SRS) treatment. An eigenvector based index, intervoxel diffusion coherence (IVDC), was calculated, which described the coherence in the distribution of the white matter tracts in a voxel and its neighborhood. The results showed the IVDC increased significantly immediately after the treatment while FA remained stable throughout the period of investigation. Therefore IVDC is more sensitive than FA in early detection of the response to the SRS treatment for VS patients.

13:30 3490. A Tract-Based Spatial Statistics Study of White Matter Compromise in Pediatric Brain Tumor Patients Treated with Cranial Radiation Donald Mabbott1, 2, Conrad Rockel1, Eric Bouffet1, 2 1The Hospital for Sick Children, Toronto, Canada; 2University of Toronto, Toronto, Canada

We examined differences in FA for children treated with CRT relative to control subjects using tract-based spatial statistics (TBSS) to determine whether these differences are diffusely present across all regions of the brain or localized to specific regions. Reduced FA in patients treated with CRT was evident relative to healthy controls across multiple regions, including the corpus callosum, internal capsule, cortico-spinal tracts, and hemispheric white matter. Using a tract-based spatial statistics methodology, we documented compromised white matter integrity in patients treated with CRT relative to controls. These differences were diffuse and there was no evidence of regional variation in FA differences between patients and controls.

14:00 3491. Differentiation Between Glioblastoma and Brain Metastasis Using Diffusion Tensor Imaging Sumei Wang1, Sungheon Kim1, Sanjeev Chawla1, Wei Guo Zhang1, Ronald L. Wolf1, Donald M. O'Rourke1, Kevin D. Judy1, Elias R. Melhem1, Harish Poptani1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA

In addition to conventional DTI metrics, ADC and FA, tensor shape measures such as linear and planar anisotropy coefficient (CL and CP) were used in this study to differentiate between glioblastoma and solitary brain metastasis. Forty glioblastoma and 19 brain metastasis patients underwent DTI studies at 3T. CL, CP, FA and ADC were measured from the enhancing part as well as peritumoral regions. CL, CP and FA values of the enhancing part in glioblastomas were significantly higher than those in metastases. These results indicate that DTI metrics including shape-oriented measures may be helpful in differentiating glioblastomas from brain metastases.

14:30 3492. Repeatability of Apparent Diffusion Coefficient and Fractional Anisotropy in Patients with Recurrent Glioblastoma Multiforme Michael John Paldino1, Dhiral Phadke1, Annick DesJardins1, James Vredenburgh1, Henry Friedman1, Daniel P. Barboriak1 1Duke University Medical Center, Durham, North Carolina, USA

This study analyzes the repeatability of diffusion tensor imaging in patients with high grade glioma. These results provide a context within which to interpret changes in diffusion parameters that occur after treatment.

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15:00 3493. Serial Diffusion Tensor Imaging to Characterize Radiation Induced Changes in Normal Appearing White Matter Following Radiotherapy in Patients with Adult Low Grade Gliomas (WHO Grade II) Shaleen Kumar1, Mohammad Haris1, Ankur Purwar2, Mani Kartick Raj1, KJ Maria Das1, Sanjay Behari1, Ram Kishore Singh Rathore2, Rakesh Kumar Gupta1 1Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India; 2Indian Institute of Technology, Kanpur, India

Quantitative evaluation of changes in normal appearing white matter (NAWM) of brain tumor patients receiving radiotherapy (RT) have been described using DTI metrics i.e. fractional anisotropy (FA) and mean diffusivity (MD). However, data on DTI metrics in NAWM irradiated to varying doses are scarce and in one recent study, confounded by the addition of chemotherapy to RT. Besides FA and MD, other DTI metrics i.e., linear case (CL), planar case (CP) and spherical case (CS) may provide additional information associated with WM injury. This study assessed the utility of various DTI metrics to characterize the threshold for detection and temporal evolution of changes in NAWM of adults with low grade glioma treated with RT. We found that upto 14-months following RT, the threshold of detection of radiation changes using FA, CL and CS is 45-50Gy while it was 50-55Gy when using MD and CP.

13:30 3494. Preliminary Results of the Effects of Higher Order Reconstruction on Diffusion MRI Data on Our Predictive Model for Tumor Recurrence Anitha Priya Krishnan1, Sharmistha Chaudhuri1, Delphine Davis1, Paul Okunieff1, Walter G. O'Dell1 1University of Rochester, Rochester, USA

Our goal is to modify the treatment margin for Stereotactic Radiotherapy of primary brain tumors in accordance to our hypothesis that the tumor cells tend to migrate along the paths of elevated water diffusion. Previously we implemented a random walk model to predict migration of cancer cells constrained by the local diffusion environment. Here we compare the results of our random walk model based on one tensor reconstruction with the model based on multi tensor reconstruction of DTI data. The hypothesis is that the multi-tensor reconstruction will better simulate the cell migration pattern in areas of fiber crossing.

14:00 3495. A Longitudinal Study of the Cortical Reorganization of Language Function in Brain Tumor Patients Kyung K. Peck1, Nicole Brennan, Bob Hou, Andrei Holodny1 1Memorial Sloan-Kettering Cancer Center, New York, USA

The purpose of this longitudinal study is to measure the dynamic changes in language organization in brain tumor patients over time in an effort to better understand the mechanism underlying cortical adaptation.Brain tumor patients with a low grade tumor directly adjacent to the language centers, were enrolled. The fMRI paradigm is designed to engage language related areas including Broca¡¯s area. Statistical parametric maps of pre-surgical, 3 months post-surgery and 6 months post-surgery fMRI language mapping supports the inter-hemispheric mechanism of cortical compensation in brain tumor patients.

14:30 3496. Spectral Analysis of Hemodynamic Response Delays in Brain Tumor Patients Johan N. van der Meer1, Sanna Gevers1, Charles B. Majoie1, Marina A. Tijssen1, Aart J. Nederveen1 1Academic Medical Centre, Amsterdam, Netherlands

Hemodynamic response delay times are assessed near tumor tissue using spectral analysis (SA) of fMRI time series. The presence of tumors can drastically alter this response time. Using SA, activation is measured near tumors where the GLM shows nothing. By using this method, the number of 'false negative' voxels are reduced.

15:00 3497. Quantification of False Negative BOLD Response; Functional Magnetic Resonance Imaging in Brain Tumour Patients S. Gevers1, J. N. van der Meer2, R. B. Willemse2, C. B.L.M. Majoie2, A. J. Nederveen2 1Academic Medical Centre , Amsterdam, Netherlands; 2Academic Medical Centre, Amsterdam, Netherlands

Functional magnetic resonance imaging (fMRI) based on the blood oxygenation level dependent (BOLD) signal, is used to assess the spatial relationship between eloquent cortical areas and brain tumour tissue. However, accumulating evidence suggests that the BOLD signal in the vicinity of tumour tissue does not reflect neuronal activity as accurately as it does in healthy brain tissue. Altered BOLD physiology might cause inverse responses to stimuli, that are missed by conventional GLM analysis. These false negative activations could undermine the applicability of fMRI in pre-neurosurgical brain mapping. In this study we quantified negative BOLD responses (NBR) in brain tumour patients using spectral analysis.

Innovative Neuroimaging Sequences & Applications I Hall D Wednesday 13:30-15:30

13:30 3498. Contrast Optimisation for SWI Venography at 7T Markus Barth1, 2, Peter J. Koopmans1 1Radboud University, Nijmegen, Netherlands; 2University Duisburg-Essen, Essen, Germany

We investigate the implications of a high magnetic field strength (7 Tesla) on MR venography based on susceptibility weighted imaging (SWI) and estimate the optimum echo time to obtain maximum contrast between blood and brain tissue. We therefore measure T2* relaxation times of gray matter, white matter, and venous blood in vivo that yield 32.9±2.3 ms, 27.7±4.3 ms, and 7.4±1.4 ms, respectively. Optimum TE was found to be 15 ms which is supported by theoretical considerations. Using this TE very high resolution 3D datasets were acquired that amazingly detailed depiction of intracortical veins of the human.

14:00 3499. Removal of Air/tissue Interface Field Effects in Susceptibility Weighted Imaging Jaladhar Neelavalli1, Yu Chung Norman Cheng2, Ewart Mark Haacke2, 3 1Wayne State University, Detroit, Michigan, USA; 2Wayne State University, Detroit,, USA; 3The Magnetic Resonance Imaging Institute for Biomedical Research, Detroit, USA

We present here a novel method for removing the rapid phase variations due to background field inhomogenieties which are caused by large susceptibility differences at air/tissue interfaces. We test the efficiency of this method in a phantom and apply it to human SWI phase images. These images are used to produce significantly higher quality susceptibility weighted magnitude images in the midbrain and forebrain regions.

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14:30 3500. Optimisation of Double-Inversion Recovery Sequences at 7T Jennifer Elizabeth Dixon1, Paul S. Morgan1, Matthew J. Brookes1, Emma C. Tallantyre1, Nikos Evangelou1, Peter G. Morris1 1The University of Nottingham, Nottingham, UK

DIR sequences have been found to be useful in the detection of cortical MS lesions. However, the low SNR available in these images at 3T suggests the importance of developing the sequence for use at higher field strengths. This requires the determination of inversion times to provide the desired contrast between grey matter and white matter, and must address the effects of the variation in flip angle due to B1 inhomogeneity at 7T. We present images acquired at both 3T and 7T for a range of TRs which successfully null the signal from WM and CSF.

15:00 3501. Detection of White Matter Disease in the Brain and Spine Using Double Inversion Recovery SPACE at 3 Tesla Agus Priatna1, Jaeseok Park2, Chin-I Chen3, Shoe Mar, Yvette Sheline3, Tammie L.S. Benzinger3 1Siemens Medical Solutions, St Louis, Missouri, USA; 2Siemens Medical Solutions, Erlangen, Germany; 3Washington University School of Medicine, St Louis, Missouri, USA

Double IR SPACE or TSE has been shown to be useful for detecting white matter diseases such as multiple sclerosis in adult brain at 1.5T. Unlike conventional technique of using conventional 2D T2-weighted Dark-Fluid imaging (FLAIR), the double IR SPACE sequence provides better contrast between the white matter and the lesion because of the suppressed white matter signal. Because of the white matter lesions can spread to the brain and the spine, it would be desired to develop method of detecting the lesions in both brain and spine in adults, and pediatrics especially. The purpose of this study is to develop a method of detecting white matter diseases in both brain and spine in both pediatrics and adults using an optimized isotropic double inversion recovery 3D SPACE sequence at 3 Tesla.

13:30 3502. Unreliability of Cortical Volumetry in Regions Near the Skull Base on 3D T1-Weighted Imaging: Comparison Study with 3D Double Inversion-Recovery Imaging Eunhye Yoo1, Dong-Hyun Kim2, Hae-Jeong Park1, Eung-Yeop Kim1 1Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea; 2Yonsei University, Seoul, Republic of Korea

3D T1-weighted imaging is based on GRE sequence. Therefore, susceptibility artifact due to air-bone interface may happen and consequently give rise to hyperintensity within the cortex, which may be a problem for accurate and reliable measurement of the cortical volume. This pitfall can be solved if imaging is obtained with FSE sequence such as 3D double inversion-recovery imaging (DIR). In this study, we demonstrated that one or more regions in the bilateral orbitofrontal, inferior temporal, and fusiform cortices showed susceptibility artifacts on 3D T1-weighted imaging, causing underestimation of cortical volume, but not on 3D DIR in the corresponding regions.

14:00 3503. Triple-Layer Appearance of the Primary Motor Cortex on Thin-Section Double Inversion-Recovery Imaging: Validation Study by Using Intraoperative Cortical Mapping Eunhye Yoo1, Dong-Hyun Kim2, Jong-Hee Chang1, Hae-Jeong Park1, Eung-Yeop Kim1 1Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea; 2Yonsei University, Seoul, Republic of Korea

Preoperative determination of the primary motor cortex (PMC) is crucial. For this purpose, many methods by using specific morphology of the cortices and sulcus have been suggested. However, no studies suggested the method using substructure of the PMC. It has been suggested that the PMC shows triple-layer appearance on thin-section 2D double inversion-recovery imaging (DIR) in all subjects more than 10 years of age. However, validation has not been performed. The triple-layer appearance on thin-section 2D DIR was validated as a new imaging marker of the PMC by using an intraoperative cortical mapping in this study.

14:30 3504. High Resolution T2* and Phase Contrast of Human AD Brain Tissue at 9.4T: A Structural Comparison Rob J.A. Nabuurs1, Julien R. Milles1, Sanneke van Rooden1, Jeroen van der Grond1, J H. Reiber1, Mark A. van Buchem1, Louise van der Weerd1 1Leiden University Medical Center, Leiden, Netherlands

To further explore possible susceptibility effects caused by amyloid β plaques, we have obtained T2*-weighted magnitude and phase images at high magnetic field and high resolution from ex vivo human AD brain tissue. Different hypo-intense regions in the magnitude data showed a large variation in the corresponding phase data, showing that at high magnetic fields, the signal phase provides additional information about microscopic variations in magnetic susceptibility.

15:00 3505. Comparison of Retinotopic Maps with Cortical Areas Identified Using High Resolution, T2*-Weighted Images Acquired at 7T Rosa Maria Sanchez Panchuelo1, Denis Schluppeck1, Stuart Clare2, Holly Bridge2, Richard Bowtell1, Sue Francis1 1University of Nottingham, Nottingham, UK; 2University of Oxford, Oxford, UK

Here we investigate the correspondence of functionally defined visual regions V1 and MT to areas displaying hypointense banding in cortical grey matter in high resolution T2*-weighted images acquired at 7 T. Retinotopic mapping based on a moving visual stimulus and 1.5 mm isotropic resolution fMRI was carried out on 4 subjects, who were subsequently imaged using a 3D gradient echo sequence providing 0.4 mm isotropic resolution. Significant overlap of areas displaying obvious banding in the T2*-weighted data, with the functionally defined V1 and MT areas was found by analysis of maps of the inflated cortex.

13:30 3506. Comparison of Inversion Algorithms in MR Elastography of the Brain Matthew Christopher Murphy1, Kevin J. Glaser1, Joel P. Felmlee1, Richard L. Ehman1 1Mayo Clinic College of Medicine, Rochester, Minnesota, USA

MR elastography (MRE) has the potential to detect mechanical changes in brain tissue that result from the progression of disease. Optimization is required to apply MRE to the brain. One important factor is comfort, which can be significantly improved by decreasing the acquisition time. This work shows that the direct inversion (DI) algorithm is preferred to local frequency estimation since its solution converges with less than two-thirds as many slices. Therefore by implementing DI, acquisition time of MRE in the brain can be reduced.

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14:00 3507. Comparison of MR Elastography of the Brain at 1.5 T and 3.0 T Matthew Christopher Murphy1, Kevin J. Glaser1, Joel P. Felmlee1, Richard L. Ehman1 1Mayo Clinic College of Medicine, Rochester, Minnesota, USA

MR elastography (MRE) is potentially capable of detecting focal or diffuse changes in shear stiffness of the brain, which result from mechanical changes in the brain due to disease progression. To develop MRE into a useful diagnostic tool for neurological disorders it must be optimized beginning with field strength. Experiments were performed in phantom and human volunteers. Phase and magnitude signal to noise ratios show that MRE data collected at 3.0 T is higher quality than data collected at 1.5 T.

14:30 3508. Adaptive Centric View Ordering for Magnetization Prepared Gradient Echo Imaging Ersin Bayram1, Charles R. Michelich1, Anthony T. Vu1, Reed F. Busse2 1GE Healthcare, Waukesha, Wisconsin, USA; 2GE Healthcare, Madison, Wisconsin, USA

Magnetization prepared gradient echo sequences are routinely used for T1 weighted isotropic brain imaging to enhance gray-white matter contrast. Views are ordered such that a fixed number of phase-encodes in a single kx-ky or kx-kz plane are collected in a segmented centric or sequential fashion after an IR pulse is applied followed by an optional delay for magnetization recovery. A 1D trajectory through ky-kz space is limiting since only certain segment sizes are allowed based on the prescribed matrix size. This work improves the efficiency of magnetization prepared brain imaging by introducing an adaptive centric view ordering. In addition to decoupling the train length from the matrix size, it also allows desirable time saving strategies such as k-space corner removal and 2D auto-calibrated acceleration with non-separable grid which are not possible with conventional view ordering, since the number of views from one kx-ky or kx-kz plane to the next varies.

15:00 3509. Ultra-Fast T2-W. Single Shot TSE and Single Shot FLAIR MR Imaging Combining SENSE, Variable Refocusing Angle and Partial Fourier: Evaluation on Cooperative and Non-Cooperative MS Patients in Comparison to Standard TSE and FLAIR Imaging Jürgen Gieseke1, Birgit Simon2, Reanate Blömer2, Hans H. Schild2 1Philips Medical Systems, Bonn, Germany; 2University, Bonn, Germany

Introduction: Single shot and high SENSE-factor enable scan time shortening of about factor 10 for T2-w. TSE and factor 5 for TSE-FLAIR [4]. Purpose of the study was to evaluate the fast T2w.technique concerning the diagnostic image quality of non-cooperative MS patients Material and Methods: Investigations were done at 3T. The sequences are combined with SENSE, partial Fourier and Flpi angle sweep. RESULTS Concerning the head motion of the non-cooperative patients a correct diagnosis were difficult, whereas in the fast images the lesions could be correct detected. DISCUSSION This technique potentially enables diagnostic image quality in non-cooperative patients.

Innovative Neuroimaging Sequences & Applications II Hall D Thursday 13:30-15:30

13:30 3510. Efficient Multi-Slice Fast Spin Echo Imaging with Reduced Flip Angles at High Field Robert Marc Lebel1, Alan H. Wilman1 1University of Alberta, Edmonton, Canada

Here we employ reduced and variable refocusing flip angles for efficient (no delay time for SAR reduction) multi-slice FSE imaging at 4.7T. We investigate the magnetization transfer effect as a function of refocusing flip angle and demonstrate 25% signal attenuation in white matter with 180 pulses, but less than 5% attenuation at 60 . We show reduced flip angles are equally applicable to very rapid and to very high resolution imaging. We present HASTE images acquired in 600 ms/slice with 109 echoes at 55 , and very high resolution images (0.4 x 0.4 x 1 mm3) acquired in 6:30 with 100 pulses.

14:00 3511. Non-Contrast Bulk Flow Imaging of Cerebrospinal Fluid (CSF) Using Time-Spatial Labeling Inversion Pulse (Time-SLIP) Shinya Yamada1, Mitsue Miyazaki2, 3, Minako Higashi4, Hitoshi Kanazawa3, Yukuo Morohoshi, Stefan Bluml5, Gordon J. McComb 1Tokai University at Oiso, Oiso, Japan; 2Toshiba Medical Research Institute USA, Vernon Hills, USA; 3Toshiba Medical Systems Corp., Otawara, Japan; 4Toshiba Medical Systems, Yokohama, Japan; 5Childrens Hospital Los Angeles, Los Angeles, California , USA

To observe bulk CSF flow, time-spatial labeling inversion pulse (time-SLIP) is applied to observe the CSF flow in a range of 1500 to 6000 ms. This technique was applied in various regions, including the aqueduct of the Sylvius, foramen of Monro, prepontine cistern and in the spinal canal. The bulk CSF flow was observed from the third to the fourth ventricle through the aqueduct. Up and down bulk CSF motions are seen in the ventral side of the subarachnoid space. In addition, CSF reflux was observed from the third ventricle to the lateral ventricle in all normal volunteers.

14:30 3512. Rapid CSF Measurement Without Operator Intervention Using BSSFP 3D Radial Acquistion Youngkyoo Jung1, Alexey A. Samsonov1, Walter F. Block1 1University of Wisconsin-Madison, Madison, Wisconsin, USA

Typical measurements of CSF are using SPGR scans or multiple acquisitions with different T1 and T2 weightings. Those methods are complicated by post-processing schemes requiring registration or segmentation. We propose a rapid, 90 sec scan for measuring CSF volume without operator intervention using a single inversion recovery (IR) balanced SSFP (bSSFP) scan with a 3D PR acquisition. A single 3D isotropic acquisition may provide higher precision, bright CSF, faster scan times, and simplified processing relative to conventional SPGR acquisition methods.

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15:00 3513. Temporal Course of Hyperdynamic Pulsatility and Ventricular Dilation in a New Rat Model of Communicating Hydrocephalus Shams Rashid1, Helene Benveniste, 12, Michael R. Egnor1, Jie Li3, James P. McAllister4, Mei Yu2, Mark E. Wagshul1 1Stony Brook University, Stony Brook, New York, USA; 2Brookhaven National Laboratory, Upton, New York, USA; 3Wayne State University, Detroit, Michigan, USA; 4University of Utah, Salt Lake City, Utah, USA

Hydrocephalus has long been thought to be caused by CSF flow obstruction or malabsorption, but this fails to explain many observations about communicating hydrocephalus (CH). In a new rat model of CH, changes in ventricular volume (VV) and CSF stroke volume (SV) in the cerebral aqueduct were investigated using MRI. Hydrocephalus developed in two very distinct forms: severe - highly elevated SV and VV, and mild - mild ventricular dilation and slightly elevated SV which dropped back to normal levels after one week. These results may have important clinical implications for understanding the significance of elevated CSF pulsations in CH.

13:30 3514. Evaluation of T1-Weighted MRI Methods for Clinical Brain Imaging at 3.0 Tesla Chen Lin1, Andrew Kalnin1, Kristine Mosier1, Annette Johnson2, Larry Friggle3, Aaron Flammang4 1Indiana University School of Medicine, Indianapolis, Indiana, USA; 2Wake Forest University School of Medicine, Winston Salem, North Carolina, USA; 3Clarian Health Partners, Indianapolis, Indiana, USA; 4Siemens Medical Solutions USA, Inc., Malvern, Pennsylvania, USA

Direct comparison of imaging quality of five T1 weighted imaging methods, conventional SE with reduced flip angle, T1 FLAIR, 2D and 3D FLASH and MP-RAGE at 3.0T was made by scanning a group of healthy adult volunteers. Based on quantitative measurement of SNR and CNR of gray matter and white matter as well as independent review by radiologists, T1 FLAIR was shown to provide the best overall image quality. Other advantages and drawbacks of each method were also analyzed.

14:00 3515. Improvement of Midbrain Nuclei Susceptibility Contrast in T1-Weighted SPGR for Image Guided Deep Brain Stimulation Nan-kuei Chen1, Geoffrey S. Young2 1Duke University, Durham, North Carolina, USA; 2Brigham and Women's Hospital, Boston, Massachusetts, USA

3D-SPGR currently used for stereotactic image guidance in deep-brain stimulation does not provide adequate midbrain nuclei contrast. Therefore an extra T2-weighted MRI is needed for midbrain nuclei visualization. However, the surgical planning based on two datasets may be susceptible to further errors related to subject movement. Here we propose a procedure capable of providing both stereotactic T1-MRI and high midbrain nuclei contrast without extra scans. Acquisition parameters of SPGR are chosen in a way that (1) T1 contrast suitable for stereotactic imaging is obtained, and (2) high midbrain nuclei contrast is achieved by performing regional susceptibility weighted reconstruction.

14:30 3516. Investigating the Function of the Cardiovascular and Respiratory Centers in the Brain Stem by Breath-Holding Using Reduced FOV EPI Technique Chun-Jung Juan1, Tzu-Cheng Chao2, Yi-Jui Liu3, Cheng-Yu Chen1, Chun-Jen Hsueh1, Chung-Ping Lo1, Hsiao-Wen Chung2, Te-Cheng Lai3, Guo-Shu Huang1 1Tri-Service General Hospital, Taipei, Taiwan; 2National Taiwan University, Taipei, Taiwan; 3Feng Chia University, Taichung, Taiwan

In skull base, the susceptibility of regional magnetic field inhomogeneity distorts the EPI images due to long readout train. We use zoom EPI technique to reduce the FOV in the phase-encoding direction to remedy the imaging distortion on EPI sequence. Then, the function of the cardiovascular and respiratory function, which are located in the lower pons, is investigated by breath-holding fMRI. Our results will show you satisfactory imaging quality of hte brain stem and activation in the lower pons in the breath-holding task.

15:00 3517. Constructive Interference Steady-State Imaging in Post-Mortem Human Brain: An Alternative or Adjunct to Conventional Autopsy? Jennifer Andrea McNab1, Ned Jenkinson2, Tipu Aziz2, Karla L. Miller1 1University of Oxford, Oxford, UK; 2University of Oxford, UK

Post-mortem diagnosis of neuropathology is an important means of learning more about diseases of the central nervous system and can have a major impact on the management of future patients. Though several studies have previously presented post-mortem MRI, most have not been optimised for the changed properties of fixed tissue. Due to similar relaxation times in WM and GM conventional T1, T2 -weighted imaging protocols no longer provide adequate contrast in fixed tissue. In this study, we present a 3D steady-state imaging protocol, which provides excellent contrast in fixed tissue.

13:30 3518. Optimization of MDEFT with FLASH-EPI Hybrid Readout for Optimum Contrast in Selected Brain Areas Steffen Volz1, Ralf Deichmann1 1Brain Imaging Center, J.W. Goethe University, Frankfurt, Germany

In fMRI the MDEFT sequence is widely used as T1-weighted reference scan with high spatial resolution because of its advantageous contrast characteristics, especially at high field strengths. An MDEFT sequence with FLASH-EPI hybrid readout and a total acquisition time of 6 min was optimized at 3T to achieve maximum CNR and SNR for cortical WM and GM and to enhance the visibility of brain structures in the basal ganglia. The SNR and CNR values achieved were similar to results reported for a standard version of MDEFT with the same spatial resolution but twice the acquisition time.

14:00 3519. Routine High Resolution MRI in Small Animals at 9.4 Tesla Using a Cryogenic Quadrature Transceive RF Probe Christof Baltes1, Nicole I. Radzwill2, Simone C. Bosshard1, Daniel Marek3, Markus Rudin1, 4 1University and ETH Zurich, Zurich, Switzerland; 2Bruker BioSpin MRI, Ettlingen, Germany; 3Bruker BioSpin AG, Fällanden, Switzerland; 4University Zurich, Zurich, Switzerland

Recently, the benefits of cryogenic RF probes for small animal MR imaging have been investigated in detail. Cooling of the RF coil and the connected preamplifier resulted in significantly increased sensitivity. The aim of this work was a comparison under in vivo conditions of a cryogenic quadrature transceive coil to a room temperature quadrature receive only coil. The comparison revealed SNR gains of 2.5 on average for both spin echo and gradient echo sequences. In addition, this flexible and robust cryogenic RF probe allowed for in vivo micro-imaging of the cerebellum in reasonable scan times.

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14:30 3520. Sleepiness and Accuracy Correlate Abnormal BOLD-FMRI Responses During Sleep Deprivation Dardo Tomasi1, Ruiliang Wang1, Frank Telang1, Vasilios Boronikolas1, Millard C. Jayne1, Gene-Jack Wang1, Joanna S. Fowler1, Nora D. Volkow2 1Brookhaven National Laboratory, Upton, USA; 2National Institutes of Health, Bethesda, USA

Here we investigate the effect of sleep deprivation (SD) on brain activation using a set of visual attention and working memory tasks with graded levels of difficulty and high-field fMRI. During the SD session, 16 healthy men had higher sleepiness, lower performance accuracy, higher thalamic activation, lower prefrontal activation, lower deactivation in the precuneus, and lower connectivity between the thalamus and the precuneus than during the rested wakefulness session. For both tasks, activation of the anterior cingulate correlated with sleepiness and accuracy. These findings suggest that under SD, accurate performance require larger recruitment of brain resources involved with alertness.

15:00 3521. Plasticity in Congenitally Blind During Object Recognition Anand Mohan Sinha1, Senthil S. Kumaran1, Rohit Saxena1 1All India Institute of Medical Sciences, New Delhi, India

The study investigates the neuronal centers associated with perception of object in congenitally blind using fMRI. We recruited thirty right handed congenitally blind subjects and 22 healthy controls. Significant bilateral parietal activation was observed in controls as observed using one-way ANOVA test (p< 0.001). The perception in congenitally blind subjects involves cingulate and temporal areas as compared to middle occipital gyrus in controls, suggesting brain reorganization associated with tactile object recognition (visual imagery) task.

13:30 3522. MRI Texture Analysis as a Non Invasive Tool to Show Cerebral Structural Changes After Herbicide Ingestion in Mice Sandra Même1, William Même, Bich Thuy Doan1, Jean-Claude Beloeil1 1CNRS CBM UPR4301, Orléans, France

Glufosinate ammonium (or phosphinothricin PPT) is the active element of herbicides widely used in agriculture or truck farming . Lots of transgenic plants resistant to that herbicide have been developed. Significant quantities of PPT are present in plants and consequently, in animal or human food which can lead to chronical intoxication. PPT also interacts with the cerebral glutamatergic system in mammalians and can, even with low dose, lead to neurological disorders. The aim of this study was to use Magnetic Resonance Imaging (MRI) coupled with Texture Analysis as a non invasive tool to evaluate the effect of PPT treatment with different doses on mice central nervous system.

14:00 3523. Detection of Radiation-Induced Brain Injuries by Multi-Modal Magnetic Resonance Imaging Kevin C. Chan1, 2, Matthew M. Cheung1, Ke Xia Cai1, Ho-fai Lau1, C N. Tam1, Si Lun Wang1, Pek Lan Khong1, Ed Xuekui Wu1 1The University of Hong Kong, Pokfulam, Hong Kong

This study aimed to employ in vivo multi-modal MR imaging to understand the radiation-induced brain damage in rats in correlation to histopathological changes at 12 months after radiation treatment. Results showed a loss in contrast in the ipsilateral corpus callosum and external capsule in T2WI, with a corresponding hyperintensity in trace map. The fractional anisotropy has also dropped in the fimbria of the hippocampus, suggestive of degeneration in this white matter structure; Significant increase in Cho:Cr and Lac:Cr ratios, and a marginally significant elevation in Glu:Cr ratio were observed at the site of radiation, whereas colocalization was found between manganese-enhanced MRI pattern and immunostaining for GFAP, MnSOD and GS, likely due to their Mn-dependent upregulation against oxidative stress and glutamate excitotoxicity.

Alzheimer's Disease, Dementia, Age Hall D Thursday 13:30-15:30

14:30 3524. Comparative Diagnostic Utility of the Different MR Modalities in Mild Cognitive Impairment and Its Use as Predictor of Dementia Nicolas Fayed1, Jorge Humberto Davila Acosta1, Antonio Oliveros1 1Hospital Quiron, Zaragoza, Spain

The objective was to evaluate the use of PWI, DWI and MRS in patients with amnesic mild cognitive impairment as predictor´s tools of conversion to Dementia. Also, we tried to differentiate the different types of aMCI using these tools. The percentage of people who converted to dementia was 45%, including not only patients with Alzheimer Disease but also mixed dementia, vascular dementia and Lewy Body Disease. MRS results showed the best area under ROC curve to predict the conversion from aMCI to Dementia, being the best predictor the ratio NAA/Cr in the Posterior cingulated gyri.

15:00 3525. Regional Assessment of White Matter Damage at Different Stages of Alzheimer's Disease Using TBSS Laura Serra1, Mara Cercignani1, Delia Lenzi1, 2, Roberta Perri1, Fabrizio Fasano1, 3, Carlo Caltagirone1, 4, Emiliano Macaluso1, Marco Bozzali1 1IRCCS Fondazione S. Lucia, Roma, Italy; 2Sapienza Università di Roma, Roma, Italy; 3Siemens Medical, Italy; 4Università di Roma Tor Vergata, Roma, Italy

It is known that Alzheimer's disease (AD) involves both white and grey matter, and that abnormalities of both tissues correlate with measures of cognitive decline. This study aims at localizing white matter abnormalities in patients with mild cognitive impairment (MCI) using tract based spatial statistics (TBSS), a novel approach to perform whole-brain analysis of diffusion tensor (DT) MRI. We found widespread white matter abnormalities in patients with AD compared to both MCI patients and healthy subjects. The areas of abnormalities in patients with MCI compared to healthy controls were less, and of lesser extent.

13:30 3526. Voxel Based Relaxometry of Alzheimer's Disease Himachandra Chebrolu1, Charles Dennis Smith1, Peter Andrew Hardy1 1University of Kentucky, Lexington, USA

Voxel Based Relaxometry was used to correlate changes in T2 with cognitive status in a group of normal, MCI and AD subjects. Results show regions of negatiave correlation between T2 and MMSE in the temporal lobe and the hippocampus consistent with the known course of atrophy in AD.

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14:00 3527. Significantly Asymmetric Patterns of Periventricular Atrophy in Alzheimer Disease, Mild Cognitive Impairment, and Memory Complainers Detected on Clinical MR Images Lucs Ferrarini1, Walter Miguel Palm1, Hans Olofsen1, Jeroen van der Grond1, Mark A. van Buchem1, Johan H.C. Reiber1, Faiza Admiraal-Behloul1 1Leiden University Medical Center, Leiden, Netherlands

The aim of this work was to investigate left-right asymmetries in the patterns of periventricular atrophy in patients with Alzheimer Disease (AD), Mild Cognitive Impairment (MCI), and memory complaints (MC), in clinical MR images. The study included 63 AD, 28 MCI, 21 MC, and 28 healthy volunteers. A robust shape analysis technique was used to highlight local ventricular shape changes and estimate both the extent and severity of periventricular atrophy. Results were clustered in symmetrical regions and compared with the Kolmogorov-Smirnov test. The analysis showed how MC and MCI affect mostly right periventricular structures, and AD mostly left periventricular structures.

14:30 3528. Metabolite Profiles in the Frontal and Occipital Cortices in Alzheimer’s Disease as Analyzed by HRMAS 1H NMR Liya Wang1, Marla Gearing1, Xiaoxia Wang1, Shaoxiong Wu1, Carolyn C. Meltzer1, Hui Mao2 1Emory University School of Medicine, Atlanta, Georgia, USA; 2Emory University School of Medicine, Atlanta, USA

Synopsis Neurochemical changes in the frontal and occipital cortices of AD and age matched non-demented controls were analyzed using HRMAS 1H NMR and intact postmortem tissue. Metabolite profiles obtained from those regions revealed statistically significant decreases of NAA, GABA, Cho, MI, aspartic (Asp) and taurine (Tau) as well as increases of phosphocholine (PC) and glyocerphosphocholine (GPC) in the AD brains. A resonance at 3.71 and 5.85 ppm, not reported previously, appeared in 75% AD samples and 91% specificity respectively. Furthermore, the abnormal metabolite profiles of AD brain were strongly correlated with the APOE genotypes of the subjects.

15:00 3529. Diffusion Tensor Imaging and Cortical Thickness Mapping of Mild Cognitive Impairment Liya Wang1, 2, Felicia C. Goldstein1, Chunchun Ni1, Mingguo Qiu3, James J. Lah1, Allan I. Levey1, Hui Mao4 1Emory University School of Medicine, Atlanta, Georgia, USA; 2The Second Hospital of Shenzhen, Shenzhen, People's Republic of China; 3Third Military Medical University, Chongqing, People's Republic of China; 4Emory University School of Medicine, Atlanta, USA

The study examined the utility of DTI and cortical thickness mapping in identifying patients with mild cognitive impairment (MCI). Fractional anisotropy (FA), apparent diffusion coefficient (ADC) and cortical thickness in the left temporal WM and GM were significantly different in MCI patients versus normal aging controls. The combination of FA and cortical thickness measurements in temporal areas improved the accuracy of differentiating MCI patients from healthy controls compared to either measure alone.

13:30 3530. Reduced Glutamate in the Hippocampus in Mild Cognitive Impairment and Alzheimer Disease Raul Rajiv Rupsingh1, 2, Michael Borrie2, 3, Matthew Smith3, Jennie Wells2, 3, Rob Bartha1, 2 1Robarts Research Institute, London, Canada; 2University of Western Ontario, London, Canada; 3Lawson Health Research Institute, London, Canada

LASER localized MRS data were acquired from the right hippocampus of 10 Normal Elderly Controls, 6 subjects with Mild Cognitive Impairment and 6 patients with Alzheimer Disease at baseline and at 1-year. No significant differences in the rate of metabolite change were found between groups. Cross-sectional analysis revealed significant differences in the levels of NAA and glutamate between groups at both time points.

14:00 3531. Assessment of Cerebral Blood Flow in Alzheimer's Disease by Continuous Arterial Spin Labeling MR Imaging Rui Wang1, Saying Li1, Xuna Zhao2, Min Chen1 1Beijing Hospital, Beijing, People's Republic of China; 2Philips Medical System, Beijing, People's Republic of China

The continuous arterial spin labeling (CASL) MR imaging is another method to detect CBF abnormalities. Our aim is to compare regional CBF values between AD patients and control subjects to explore the clinical utility of CASL. Eighteen AD patients and 15 control subjects underwent 3.0 T CASL and structural MRI. The CBF values of bilateral frontal, temporal, temporoparietal, parietal cortices and hippocampal areas were significantly decreased relative to control subjects(P<0.05). CASL can show regional hypoperfusion with AD, in cerebral regions involved similar to that seen with SPECT. The results suggest CASL is a useful tool for CBF characterization of AD.

14:30 3532. Regional Demyelination of Subcortical White Matter in Early Alzheimer’S Disease: A Magnetization Transfer Imaging Study Eleonora Fornari1, Maria G. Knyazeva1, Philippe Maeder1, Joseph Ghika1, Andrea Brioschi1, Isebelle Bourquin1, Reto Meuli1 1Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland

Alzheimer’s disease is a neurodegenerative disorder manifested by progressive cognitive deterioration. Since higher cognitive functions are based on distributed neural networks, the AD-associated cognitive impairment is expected to result from the compromised cortical connectivity. The aim of this study is to assess the regional state of myelination of the subcortical white matter in the newly diagnosed AD patients.Our results point to a diffused degenerative process affecting the subcortical WM early in AD. Regional mapping of myelin loss in AD patients is an accurate tool providing anatomical information that can explain clinical manifestations of the disease, and its early pathogenesis.

15:00 3533. T1rho MRI as a Clinical Biomarker of Alzheimer's Disease Matthew A. Sochor1, 2, Christopher Davatzikos, Elias R. Melhem1, Christopher M. Clark, Ravi Reddy1, Ari Borthakur1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA

Earlier diagnosis of Alzheimer’s Disease (AD) is essential to the development of drugs and treatments to halt or reverse the disease’s progression. In an ongoing clinical study, T1rho values are measured in the temporal lobe (TL) of AD and mildly cognitively impaired (MCI) patients, and age-matched controls. T1rho values are automatically reported after segmentation of gray and white matter in the TL. We found an increase of 5% (p<0.05) in gray matter and 8% (p<0.01) in white matter T1rho in AD patients over controls. The MCI cohort’s average T1rho values were between the AD and control cohorts.

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13:30 3534. Resting State FMRI of the Early Stages of Alzheimer's Desease Tommaso Gili1, 2, Laura Serra3, Federico Giove1, 2, Delia Lenzi2, 3, Emiliano Macaluso3, Carlo Caltagirone3, 4, Bruno Maraviglia, 12, Marco Bozzali3 1Enrico Fermi Center, Rome, Italy; 2Sapienza University, Rome, Italy; 3IRCCS Santa Lucia Foundation, Rome, Italy; 4Tor Vergata University, Rome, Italy

The synchrony of low-frequency fluctuations in resting stat fMRI time series implies that there is underlying functional organization of the brain. In the present work, we compare low frequency correlation analysis obtained from patients with amnestic Mild Cognitive Impairment and patients with Alzheimer’s Disease (AD) to that obtained from an age-matched group of healthy subjects. Our study suggests that a pattern of abnormalities, similar to the one previously obtained from AD patients, is already present in patients with MCI, thus characterising the cognitive dysfunction occurring in AD pathology since its early stages.

14:00 3535. High Field Amyloid Imaging Sanneke van Rooden1, Mathias van Osch2, Wouter Teeuwisse2, Rob Nabuurs2, Louise van der Weerd2, Mark van Buchem2, Jeroen van der Grond2 1Radiology LUMC, Leiden, Netherlands; 2Radiology LUMC, Netherlands

Alzheimer's Disease (AD) is characterized neuropathologically by extracellular amyloid plaques. The specific aim of the study was to find optimal acquisition parameters to visualize ex vivo the amyloid burden and small microbleeds in deceased HCHWA-D patients at whole body 7T. The advantage of the HCHWA-D model is that all mutation carriers have a severe vascular amyloid burden. Gradient echo brain imaging at high field strengths offers excellent possibilities to visualize small distortions of the magnetic field, offering the potential to detect amyloid plaques. A multi-echo approach may be useful to differentiate between distortions caused by air bubbles and iron accumulation

14:30 3536. Relation of Corpus Callosum Commissural System Volume and Its Projection Regions to Volume of White Matter Lesion Load and Whole Brain Atrophy with Age in Healthy Adults Svetlana Egorova1, M P. Sampat1, C Sander1, Deborah Blacker2, M S. Albert2, R J. Killiany3, C R. Guttmann1 1BWH, HMS, Boston, Massachusetts, USA; 2MGH, HMS, Boston, Massachusetts, USA; 3BU, Boston, Massachusetts, USA

We analyze the degree of age-related atrophy changes of the corpus callosum during normal aging in healthy subjects and its relationship with white matter lesion load and whole brain atrophy.

15:00 3537. Differential Effects of Age and Hypertension on Brain Anatomy and Physiology Assessed by Regional T2* Relaxometry and Volumetry Karen M. Rodrigue1, E. Mark Haacke1, Naftali Raz1 1Wayne State University, Detroit, Michigan, USA

Within a healthy aging model, regional T2* values decline with age in the prefrontal cortex, medial temporal structures and striatum, but not in the primary visual cortex. Those differences are enhanced by hypertension. In the hippocampus and the entorhinal cortex, the effect of age on T2* is stronger than on the respective volumes.

13:30 3538. Anterior-To-Posterior Hippocampal Metabolic Heterogeneity in Healthy Elderly and Young Adults Using 3D 1H MR Spectroscopy Kevin King1, Songtao Liu1, Lidia Glodzik-Sobanska1, James Babb1, Mony de Leon1, Oded Gonen1 1NYU School of Medicine, New York, New York, USA

To quantify the metabolite concentrations along the anterior-posterior axis of the hippocampus in healthy young and elderly, 6 ¡®young¡¯ and 6 ¡®elderly¡¯ volunteers underwent 3D 1H-MRSI at 3T with (0.5 cm)3 spatial resolution. Absolute concentrations of NAA, Cho and Cr were obtained in each voxel. A significant metabolic heterogeneity is observed between young and old and along the anterior-posterior axis of the hippocampus in both age groups. These underscore the importance of age-matching and that consistent voxel placement is important for correct comparisons of both absolute metabolic levels and metabolite ratios in (a) longitudinal intra-subject; and (b) inter-subject cross-sectional studies.

14:00 3539. Cortical Thickness Measurements with Buried Sulcus Recovery from MRI: An Application to Dementia Sandhitsu R. Das1, Brian B. Avants1, Murray Grossman1, James C. Gee1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA

A new methodology for cortical thickness measurements from MR images is presented. The method uses registration-based techniques to define correspondence between white matter and gray matter surface points and the distance between corresponding points is defined as thickness. Using diffeomorphic mapping allows for resolution of deep sulci often mislabeled as gray matter. The method is applied to a longitudinal study of thickness change in frontotemporal dementia.

14:30 3540. Cerebral Vasoreactivity as the Main Determinant of Progression of White Matter Hyperintensities in Small Vessel Disease: CADASIL as a Monogenetic Model Michael K. Liem1, Saskia A.J. Lesnik Oberstein1, Joost Haan, 12, Rivka van den Boom1, Michel D. Ferrari1, Mark A. van Buchem1, Jeroen van der Grond1 1Leiden University Medical Center, Leiden, Netherlands; 2Rijnland Hospital, Leiderdorp, Netherlands

In this study we investigated the role of basal total cerebral blood flow (TCBF) and cerebral vasoreactivity (CVR) on progression of characteristic MRI abnormalities in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), which is a monogenetic model of arterial small vessel disease. We found that low CVR is associated with faster progression of white matter hyperintensities, but not with progression of lacunar infarcts or microbleeds. TCBF was not associated with progression of MRI abnormalities. CVR is an important causal factor in development of white matter hyperintensities in CADASIL and possibly also in small vessel disease in general.

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15:00 3541. Periventricular Apparent Diffusion Coefficient, Cerebrospinal Fluid (CSF) Aqueductal Flow Rate and Evan’s Index - Value of Pre and Post Shunt Comparison in Idiopathic Normal Pressure Hydrocephalus (NPH) Samuel ES Ng1, Angela MS Low1, Kok Kee Tang2, Robert K. Kwok1 1Mount Elizabeth Hospital, Singapore, Singapore; 2KK Tang Adult & Pediatric Neurosurgery, Singapore

We believe that the symptoms of NPH are caused not by ventriculomegaly, but by a blockage to the flow of extracellular cerebral fluid. If the former were true, shunt responders would show interval decrease in FR / EI. If the latter were true, responders would post an interval decrease in ADC, vice versa for non-responders. In our study, for responders, improvement in MRI readings for ADC, FR and EI was seen in 100%, 67% and 100%. For the non-responders, similar readings ADC, FR and EI were seen in 0%, 67%, and 67%. Only the ADC showed total concordance with shunt response.

13:30 3542. Measurement OfTransependymal Bulk CSF Flow in Communicating Hydrocephalus Noam Alperin1, Sang H. Lee2, William Chiang1, Roberta Glick3, Tadanori Tomita4, John Curran4 1University of Illinois, Chicago, Illinois, USA; 2University of Illinois, Chicago, Illinois, USA; 3Rush University, Chicago, Illinois, USA; 4Children's Memorial Hospital, Chicago, Illinois, USA

Periventricular hyper intensities is often seen in hydrocephalous and is associated with edema or CSF retention. The origin for this increased interstitial water content could be local, either vascular or cellular, or ventricular by transependymal bulk CSF flow. Identifying the possible origin for these hyper intensities may help establish the correct diagnosis and treatment. We tested the hypothesis that ventricular-to-parenchyma transependymal flow is associated with reversed net CSF flow through the aqueductal by measurements of bulk aqueductal CSF flow in hydrocephalic patients and in two control groups in whom no hyperintensities were present. Revered balk flow was found only in the hydrocephalic group. All patients with negative net balk flow demonstrated white matter periventricular hyperintensities.

14:00 3543. Voxelwise DTI and FLAIR Correlation Analysis for Characterization of White Matter Degeneration Wang Zhan1, Yu Zhang1, Susanne Mueller1, Peter Lorenzen1, Efstathios Hadjidemetriou1, Xiaoping Zhu1, Shannon Buckley1, Marzieh Nezamzadeh1, Norbert Schuff1, Michael W. Weiner1 1University of California San Francisco, San Francisco, California , USA

White matter (WM) degeneration has been investigated with two major MRI modalities: i.e. diffusion tensor imaging (DTI) to detect the alterations of microstructural integrity in WM, and fluid attenuated inversion recovery (FLAIR) to exam the macroscopic WM lesions (WML). However, the specific relationship between them remains largely unknown in characterizing lesion severity. The present study aims to clarify this relationship by using voxelwise correlation analysis between DTI and FLAIR images acquired from a same group at 4T. Results from both in-vivo and simulations suggest that combined DTI and FLAIR modalities together may provide higher specificity in characterizing the WM degeneration than each alone.

14:30 3544. Detecting Diffuse White Matter Alterations in Healthy Volunteers Using Tissue Specific Imaging: Potential Implications for Cognitive Function Vasiliki N. Ikonomidou1, Susan K. Stern1, Antonio Gallo1, Iordanis E. Evangelou1, Joan M. Ohayon1, Mary Ehrmantraut1, Irene Cortese1, Constantinos D. Frantzis1, Henry F. McFarland1, Robert L. Kane2, Francesca Bagnato1 1National Institutes of Health, Bethesda, USA; 2VA Medical Center, Baltimore, USA

Diffuse white matter changes are a common finding in clinically healthy subjects. No clinical significance has been attributed to them. In this study, we present a semi-automated method to identify and quantify affected white matter tissue using Tissue Specific Imaging. Results from 21 healthy volunteers indicate that the affected volume fraction has significant correlations with the subjects’ scores in some components of a comprehensive cognitive battery for multiple domain evaluation.

15:00 3545. Radial Diffusivity Measurement of the Corpus Callosum to Investigate Normal Aging and Pathological Cognitive Decline Fabrizio Fasano1, 2, Mara Cercignani1, Barbara Basile1, 3, Laura Serra1, Delia Lenzi1, 4, Carlo Caltagirone1, 5, Marco Bozzali1 1Fondazione Santa Lucia, Roma, Italy; 2Siemens Medical, Milano, Italy; 3Scuola di Psicoterapia Cognitiva (SPC), Roma, Italy; 4Università La Sapienza, Roma, Italy; 5Università Tor Vergata, Roma, Italy

An high sensitivity radial diffusivity estimation is performed in the corpus callosum of 19 young and 6 ederly healthy volunteers, and on 6 mild cognitive impairment and 4 alzheimer disease patients Our results show a correlation between radial diffusivity values in the genu of corpus callosum and normal aging. In the same region also a promising trend of the mean radial diffusivity is found among groups.

Psychiatric MRI/MRS Hall D Thursday 13:30-15:30

13:30 3546. Magnetization Transfer Imaging and Volume Changes Detected by MRI in First-Episode Schizophrenia Gary Price1, Mara Cercignani1, Elvina M. Chu1, Thomas R E Barnes2, Gareth J. Barker3, Eileen M. Joyce1, Maria A. Ron1 1University College London, London, UK; 2Imperial College Faculty of Medicine, London, UK; 3King’s College London, London, UK

This study uses 3D IR-SPGR and 3D MT-SPGR sequences to study 48 patients with 'first-episode' schizophrenia and 47 controls. Two volumes from the MT-SPGR sequence were co-registered using FLIRT and MTR maps were then calculated on a pixel-by-pixel basis. SPM2 was then employed integrating the "optimised VBM" approach. MTR reductions were seen in the patient group but not controls. Grey and white matter loss was also seen in the patient group, as well as grey matter increases in the patient group in the superior frontal gyral region. The results suggest that MTR and volume abnormalities detected in patients may reflect different underlying processes or different stages of a process in the illness.

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14:00 3547. ROI-Based VBM Study of Amygdala and Hippocampus in First-Episode Treatment Naive Schizophrenia Patients Ling Zou1, Luo Ouyang2, Wei Deng3, Qin Chen3, Zhengyang Li1, Weiwei Zhang1, Su Lv1, Yi Wei1, Tijiang Zhang1, Xiaoqi Huang1, Dongming Li4, Xiuli Li4, Tao Li3, QiYong Gong1 1West China Hospital, Sichuan Universty, Chengdu, People's Republic of China; 2South West University, People's Republic of China; 3West China Hospital, Sichuan Universty, People's Republic of China; 4West China Hospital, Sichuan University, Chengdu, People's Republic of China

Small medial temporal lobe volumes have been reported as one of the common findings in schizophrenia patients, some of them with inconsistent substructure changes. However, most studies recruited chronic patients regardless of medication. We applied ROI based VBM study of gray matter density in amygdala and hippocampus to patients only with first-episode, antipsychotic-naive schizophrenia, and consequently observed no significant changes. It is likely that the observed structural abnormalities of amygdale and hippocampus in previous studies may attribute to medication and/or subsequent neurodegenerative changes over time. Future large cohort study is necessary to gain further insight into our current findings.

14:30 3548. A Seven Year Longitudinal 31P MRS Study of Schizophrenia Jodi E. Miller1, 2, Peter C. Williamson2, Ravi S. Menon2, 3, R W J Neufeld2, Dick J. Drost1, 2 1Lawson Health Research Institute, London, Canada; 2University of Western Ontario, London, Canada; 3Robarts Research Institute, London, Canada

Our continuing longitudinal study of schizophrenia has measured phosphorus brain metabolism in patients and controls for a third time, seven years after the onset of disease using 3 dimensional chemical shift imaging. This acquisition has allowed us to observe the effect of length of illness on metabolite changes in patients. In the anterior cingulate there was a significant decrease in breakdown and synthesis products in patients as compared to controls. In the left thalamus there was a trend of decreased breakdown products in patients as compared to controls. Breakdown products in both of these regions were negatively correlated with length of illness.

15:00 3549. 2-D 1H MRSI Study of Prefrontal Cortex in the Brain of First-Episode Psychosis Patients Jing-Huei Lee1, 2, Wen-Jang Chu1, Mi Jung Kim1, Caleb M. Adler1, Stephen M. Strakowski1 1University of Cincinnati, Cincinnati, USA

The specific abnormalities of neurochemistry underlying the development of psychotic disorders (schizophrenic, schizoaffective, and bipolar disorder) are still not completely known. Some neuroimaging studies had reported that neuroanatomical changes in certain brain regions had been linked to these psychotic disorders. These aberrant changes are observed most prominently in medial temporal and prefrontal lobe regions. In this work, we extended the neuroimaging findings to the study of neurospectroscopy using 2D 1H MRSI with a focus on the prefrontal lobe region. Our findings suggest elevated choline levels in the prefrontal region may be associated with the severity of psychotic symptoms.

13:30 3550. The Subdivided Corpus Callosum in Schizophrenia: A DTI Study Pin-Yi Chiang1, Kun-Hsien Chou2, Yi-Ping Chao3, I-Yun Chen4, Tung-Ping Su5, Ching-Po Lin1, 4 1Institute of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan; 2Institute of Biomedical Engineering, National Yang Ming University, Taipei, Taiwan; 3Institute of Electrical Engineering, National Taiwan University, Taipei, Taiwan; 4Institute of Neuroscience, National Yang-Ming University, Taipei, Taiwan; 5Taipei Veterans General Hospital, Taipei, Taiwan

Numbers of studies have suggested that schizophrenia is a condition of abnormal connectivity in the cortico-cortical connections and the connections between the hemispheres. To understand the abnormal areas and the related connections, 25 schizophrenia patients and 25 healthy subjects were acquired and compared using DTI technique. Comparing regional differences of fraction anisotropy (FA) between the patient-control groups can reflect the abnormal connectivity between the hemispheres in the specific cortical regions. The corpus callosum for analyzing was defined on the midsagittal slice and subdivided to 8 areas based on a method described by Witelson in 1989. The results indicated that the communication between the hemispheres in prefrontal lobe, motor area, somaesthetic area and inferior temporal lobe were poor in schizophrenia patients.

14:00 3551. Gender Difference in Schizophrenia Revealed by Resting-State Functional MRI Xiaoqi Huang1, 2, Qihong Zou2, Wei Deng1, Su Lui1, Ling Zou1, Tijiang Zhang1, Xiuli Li1, Dongming Li1, Tao Li1, Yufeng Zang2, Qiyong Gong1 1West China Hospital of Sichuan University, Chengdu, People's Republic of China; 2Beijing Normal University, Beijing, People's Republic of China

Regional Homogeneity (ReHo) hypothesized that the time series of fMRI signals within a functional cluster are similar to each other£and it utilized KCC (Kendall's coefficient concordance) to measure this similarity in a voxel-wise way. Abnormal ReHo is possibly related to the changes of temporal aspects of neural activity in regional brain. The present study used ReHo method to study the gender difference in schizophrenia in brain activity at resting state which gave further evidence of gender effect on this illness from a functional perspective.

14:30 3552. Alterations in BOLD Response and Metabolite Concentrations Support Decreased Glial Enzyme Activity in Major Depression: A Quantitative JPRESS and FMRI Study Martin Walter1, Anke Henning2, Simone Grimm3, Rolf Feodor Schulte2, Johannes Beck3, Ulrike Dydak2, Betina Schnepf2, Heinz Böker3, Peter Boesiger2, Georg Northoff1 1Otto-von-Guericke University Magdeburg, Magdeburg, Germany; 2University and ETH Zurich, Zurich, Switzerland; 3University of Zurich, Zurich, Switzerland

Metabolic and functional alterations inside the pgACC were assessed by simultaneous quantitative in-vivo 2D-JPRESS measurements of GABA, glutamate and glutamine levels, fMRI measurements during emotional stimulation and subjective evaluation of the emotional state in healthy volunteers and patients with major depressive disorder (MDD). An altered excitation/inhibition balance was found. Changed neurotransmitter concentrations specifically relate to reduced deactivation, and altered subjective evaluation of emotional intensities and anhedonia scores in the patient group. In addition, a decreased activity of glial enzymes that are mediating the Glu reuptake from the synaptic cleft as well as the transformation of glutamate into glutamine is hypothesized.

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15:00 3553. White Matter Disruption in Early- And Late-Onset Depression: A Tract-Based Spatial Statistical Analysis KiSueng Choi1, Richard Cameron Craddock2, Paul E. Holtzheimer1, Xiaoping Phillip Hu3, Helen S. Mayberg1 1Emory University School of Medicine, Atlanta, USA; 2Georgia Institute of Technology, Atlanta, USA; 3Emory University and Georgia Institute of Technology, Atlanta, USA

We used Track-Based Spatial Statistics to assess differences in WM FA associated with major depressive disorder. 23 subjects were classified into four groups (young & old controls, young early-onset & old late-onset major depression). A significant reduction was found between young patients and young controls in interesting region which is spatially approximate to a target proposed for deep brain stimulation for treatment resistant depression. No significant differences were found between older controls and old patients due to a large variance in FA resulting from brain atrophy. These results suggest that TBSS may be useful for comparing white matter integrity between clinically relevant populations.

13:30 3554. 1H MRS Neurochemical Predictors of Response to Intravenous Ketamine in Treatment-Resistant Depression Sanjay J. Mathew1, Rebecca B. Price1, James Murrough1, Marije Aan Het Rot1, Kate Collins1, Xiangling Mao2, David Reich1, Dennis Charney1, Dikoma C. Shungu2 1Mount Sinai School of Medicine, New York, New York, USA; 2Weill Medical College of Cornell University, New York, New York, USA

Twelve patients with treatment-resistant major depression were treated with open-label intravenous ketamine, an NMDA antagonist with rapid antidepressant effects. 1H-MRS scans completed prior to treatment revealed a positive association between concentrations of Glx/water in the occipital lobe and pre-treatment depression and anxiety scores. Lower occipital GABA/water was associated with superior treatment response 24 hours post-infusion. These findings add to a growing literature supporting the utility of neuroimaging measures as predictors of response to specific psychiatric treatments.

14:00 3555. A Combined Functional-Structural Connectivity Analysis of Major Depression Using Joint Independent Components Analysis KiSueng Choi1, Richard Cameron Craddock2, Paul E. Holtzheimer1, Zhi Yang3, Xiaoping Phillip Hu3, Helen S. Mayberg1 1Emory University School of Medicine, Atlanta, USA; 2Georgia Institute of Technology, Atlanta, USA; 3Emory University and Georgia Institute of Technology, Atlanta, USA

We integrated resting state functional connectivity (FC) and fractional anisotropy (FA) data in a joint ICA (Ranking and Averaging ICA by Reproducibility) to better characterize connectivity of the subgenual cingulate cortex in major depression. We examined 9 controls and 4 patients. The FC differences incorporate regions previously identified in a seed PLS analysis of a similar population and FA differences are spatially concordant with FC result areas suggesting that WM tracts connecting these regions may be different in depressed versus control subjects. These results indicate that disease related alterations in functional connectivity may be mediated by WM structural abnormalities.

14:30 3556. A 1H Magnetic Resonance Spectroscopy Study in Adults with Obsessive Compulsive Disorder: Relationship Between Metabolite Concentrations and Symptom Severity Maria Ljungberg1, 2, Göran Starck1, Marie Nilsson, Lars Jönsson, Tord Ivarsson, Stefan Lundberg, Susanne Ribbelin11, Sven Ekholm, Arvid Carlsson, Eva Forssell-Aronsson1, Maria Carlsson 1Göteborg University, Göteborg, Sweden

Nine patients with moderate to severe OCD and 16 healthy controls were examined with 1H MRS (TE30ms) in three locations in the brain; the caudate nucleus, the anterior gyrus cinguli and the occipital cortex. The aim was to explore 1) metabolite concentration differences between patients and healthy volunteers, and 2) the relationship between metabolite concentrations and symptom severity in the patient group. LC Model and PCA-statistics was used for analysis. PCA did not reveal any separation between patients and controls with respect to MRS metabolites. However, PLS, disclosed a strong relationship between some of the metabolites and OCD symptom severity.

15:00 3557. Regional Gray Matter Volume Abnormalities in Obsessive-Compulsive Disorder: A Study with the Automated Region-Of-Interest Measurement Method Osamu Togao1, Takashi Yoshiura1, Tomoyuki Noguchi1, Akio Hiwatashi1, Koji Yamashita1, Eiki Nagao1, Tomohiro Nakao1, Maiko Nabeyama1, Hiroshi Honda1 1Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan

The purpose of this study was to assess regional gray matter (GM) volume abnormality in obsessive-compulsive disorder (OCD) using the automated region-of-interest method. The advantage of this technique is to be free from man-made technical bias, which is frequently seen in manual ROI method. We compared the regional GM volume between 24 OCD patients and 27 normal control subjects. This study revealed the GM volume abnormalities in the bilateral orbitofrontal cortex and the right anterior cingulated cortex. Results indicated that these structural abnormalities would be related to the pathophysiology of OCD.

13:30 3558. Dysfunction of the Fronto-Striatal-Insular Network in Drug-Naive Adolescents with Attention Deficit Hyperactivity Disorder: A Resting-State FMRI Study Xi-Nian Zuo1, 2, Chao-Zhe Zhu2, Qing-Jiu Cao3, Vesa Kiviniemi4, Yu-Feng Wang3, Yu-Feng Zang2 1Institute of Automation, Chinese Academy of Sciences, Beijing, People's Republic of China; 2Beijing Normal University, Beijing, People's Republic of China; 3Peking University, Beijing, People's Republic of China; 4Oulu University Hospital, Oulu, Finland

In this study, we investigated the fronto-striatal-insular network in boys with attention deficit hyperactivity disorder (ADHD) by using resting-state fMRI, which is believed to reflect spontaneous neuronal activity. Independent component analysis (ICA) was used to reveal the interested network. We found that boys with ADHD showed significantly decreased connectivity in the fronto-striatal-insular network compared to controls. This abnormal network was almost exclusively within the right hemisphere. By using a new technique (resting-state fMRI) and new analysis approach (ICA), the current results provided new evidence of fronto-striatal-insular network abnormality as well as right hemisphere abnormality in ADHD.

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14:00 3559. Decreased Functional Connectivity in the Brodmann Area 10 Network in Heroin Users Wenjun Li1, Chunming Xie2, 3, Xiuzhen Di2, Haiyan Meng2, Jun Xie1, Zhilin Wu1, Lin Ma4, Zheng Yang2, Shi-jing Li1 1Medical College of Wisconsin, Milwaukee, USA; 2Beijing Institute of Basic Medical Science, Beijing, People's Republic of China; 3Medical College of Southeast University, Nanjing, People's Republic of China; 4PLA Hospital, Beijing, People's Republic of China

Based on the results from Voxel-Based Functional connectivity MRI (fcMRI) using seed ROI approach has been widely used in current neurological research (e.g. in depression, schizophrenia, and Alzheimer’s disease). However, a dearth of literature has been published on heroin-related studies. The purpose of this study is to investigate the changes of functional connectivity (FC) changes between non-heroin participants and heroin abusers. Based on the results from Voxel-Based Morphometry (VBM), we focus on how the decreased gray matter concentration in the region of Brodmann Area (BA) 10 could affect the FC in the brain of heroin users.

14:30 3560. Impaired Frontal Executive Function in Abstinent Heroin Addiction: An FMRI Study Li-ping Fu1, Yan Wang, Shi-jiang Li2, Guo-hua Bi1, Zhi-tong Zou, Xian Xu, En-mao Ye1, Lin Ma, Zheng Yang1 1Beijing Institute of Basic Medical Science, Beijing, People's Republic of China; 2Medical College of Wisconsin, Milwaukee, USA

Heroin impact negatively on the frontal cognitive function after repeated abuse. In this study, an fMRI method with Go-NoGo task was employed to detect the neuroanatomic substrates involved in inhibitory response in 18 healthy controls and to probe the frontal neurocognition of 30 protracted withdrawal heroin dependents. Our results demonstrated midline structure involved in response inhibition and impaired frontal executive function lasted even abstinence for two months. The disrupted frontal executive function maybe the common dominator for various substances abuse, which contribute to the vulnerability of heroin users to the conditioned cues, craving for drug and lead to relapse

fMRI: Acquisition Methods Hall D Monday 14:00-16:00

14:00 3561. Multi-Echo Parallel Imaging Accelerated FMRI with Susceptibility-Induced Off-Resonance Compensation Heiko Schmiedeskamp1, Rexford David Newbould1, Klaas Paul Pruessmann2, Roland Bammer1 1Stanford University, Stanford, California , USA; 2University and ETH Zurich, Zurich, Switzerland

Off-resonance due to susceptibility effects typically results in signal dropouts if long echo times and/or thick slices are used such as for BOLD fMRI. To compensate for these effects, additional z-shim gradients can be applied. Here, parallel imaging shortened readouts allow multi-echo acquisitions, with varying z-shims prior to the echo trains. Whole-brain fMRI measurements can thereby be performed with minimized signal loss in dropout regions and no time penalty.

14:30 3562. PAID FMRI at 7T - Investigating the Benefits of Multi-Echo EPI at High Field Benedikt Andreas Poser1, 2, David Gordon Norris1, 2 1Radboud University, Nijmegen, Netherlands; 2University Duisburg-Essen, Essen, Germany

One drawback of commonly the used GE-EPI for functional brain imaging is that only one TE can be used. This implies a compromise in global functional sensitivity as optimal TE varies over the brain, due to considerable spread in gray matter T2*. To overcome this, the use of multi-echo EPI has been advocated, and shown to allow substantial sensitivity increases at 1.5 and 3T for various echo weighting strategies. Here in we investigate the value of parallel-acquired inhomogeneity desensitized (PAID) fMRI at 7T. Initial experiments show that CNR benefits are obtained across the brain, and hat distortion is markedly reduced.

15:00 3563. Highly Accelerated FMRI: A Feasibility Test of Image Support Reduction Technique Feng Huang1, Hu Cheng2, Yu Li1 1Invivo Corporation, Gainesville, Florida, USA; 2Indiana University, Bloomington, Indiana, USA

Feasibility of the application of image support reduction technique for fMRI is reported. Experimental results show that active regions can still be accurately detected at acceleration factor as high as 4 with image support reduction technique. Therefore, image support reduction can be adopted in fMRI to achieve images with higher spatial resolution.

15:30 3564. Increasing Spatial Coverage for High Resolution FMRI Studies Yanle Hu1, Gary H. Glover2 1University of Texas at Austin, Austin, Texas, USA; 2Stanford University, Stanford, California , USA

A novel technique which combines the 3D acquisition method with the UNFOLD technique is proposed to increase spatial coverage for high resolution fMRI studies. Theoretical analysis based on a thermal noise model shows that compared to the traditional method, the proposed method can acquire more slices at a similar SNR performance given the same volume TR and total scan time. A comparison study performed on normal volunteers confirmed our theory.

14:00 3565. Hemodynamic Properties of Passband B-SSFP FMRI Jin Hyung Lee1, Gary H. Glover1, Taeksoo Kim1, Dwight G. Nishimura1, John M. Pauly1 1Stanford University, Stanford, California , USA

Passband b-SSFP fMRI shows great promise with its distortion-free, high-resolution imaging capabilities. In this paper, we present quantitative results on the contrast and temporal dynamics of passband b-SSFP fMRI.

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14:30 3566. Considerations on Scan Parameters in Passband SSFP FMRI Taek Soo Kim1, Jongho Lee, 12, Jin Hyung Lee1, Gary H. Glover1, John Mark Pauly1 1Stanford University, Stanford, California , USA; 2National Institute of Health, Bethesda, Maryland, USA

Passband SSFP fMRI generates higher functional contrast in relatively short TRs, providing the potentials for high-resolution fMRI. Moreover, it can emphasize the signal from capillaries in the extravascular space and has a potential to better localize the activation area. As shown in previous studies, the functional contrast and the signal to noise ratio in balanced SSFP fMRI are functions of MR parameters. However, its optimal scan parameters have not been investigated systematically. In this study, we suggest a guideline for selecting the scan parameters for passband SSFP fMRI.

15:00 3567. High Resolution 3D Functional Images of the Human Olfactory Bulb Using Passband SSFP at 3T Todd B. Parrish1, YuFen Chen1, Wen Li1, James Howard1, Jay A. Gottfried1 1Northwestern University, Chicago, Illinois, USA

A novel new passband SSFP sequence is used to acquire high resolution (1x1x2mm), artifact free fMRI images of the human olfactory bulb at 3T during an odor detection task. The implementation of the 3D FISP sequence provided similar contrast to standard EPI BOLD when the two imaging methods were compared in the motor cortex. The importance of imaging the bulb is equivalent to imaging V1 in the visual system, since it is the first level of input. The ability to obtain fMRI data of the bulb will further the understanding of the olfactory system.

15:30 3568. T2-Weighted, 3D Whole Brain FMRI at 3 T and 7 T Using S2-SSFP Markus Barth1, 2, Stephan A. Kannengiesser3, Heiko Meyer3, David G. Norris1, 2 1Radboud University, Nijmegen, Netherlands; 2University Duisburg-Essen, Essen, Germany; 3Siemens Medical Solutions, Erlangen, Germany

In this abstract it is shown that the S2-SSFP signal represents a viable alternative to spin-echo EPI for fMRI at both 3 and 7T. In order to achieve the necessary temporal resolution a 3D acquisition scheme combined with acceleration along two spatial axes was employed. Functional data showed good spatial localisation and sensitivity while avoiding both image distortion, and problems of power deposition. In conclusion whole-brain fMRI at 7Tesla will be possible using the S2-SSFP sequence and partial parallel imaging.

14:00 3569. High Resolution FMRI Using Short Axis Readout Propeller EPI (SAP-EPI) Anders Nordell1, Samantha Holdsworth2, Rexford Newbould2, Roland Bammer2, Stefan Skare2 1Karolinska University Hospital, Stockholm, Sweden; 2Stanford University, Palo Alto, California , USA

Short Axis readout propeller EPI (SAP-EPI) is a T2*-weighted sequence well suited for BOLD imaging. SAP-EPI has properties that enable high resolution imaging, while maintaining good volume coverage and dynamic resolution. This study investigates the reproducibility of the BOLD response using a simple fMRI stimulus and compares high resolution SAP-EPI to conventional ssEPI at high and low resolution.

14:30 3570. Evaluation of K-T BLAST Applied to Spin-Echo Based BOLD Functional MRI Jane Frances Utting1, 2, Rani Bhaninny1, René Vohn1, Ralph Schnitker1, Sebastian Kozerke2, Thoralf Niendorf1 1RWTH-Aachen, Aachen, Germany; 2University and ETH Zuerich, Zuerich, Switzerland

Motivated by the prospect of anatomically accurate fMRI using spin-echo based imaging, with acquisition times and RF power deposition reduced by applying spatio-temporal correlation techniques (k-t BLAST), this study was designed to investigate the temporal fidelity of k-t accelerated displaced UFLARE applied to BOLD contrast fMRI. Controlled temporal variations in signal intensity in a test object and fMRI in subjects performing a block motor paradigm demonstrate the feasibility of applying k-t acceleration to fMRI and the importance for temporal fidelity of including training data in k-t BLAST reconstructions.

fMRI: Animal Models Hall D Monday 14:00-16:00

14:00 3571. The Effects of Ambient MRI Scanner-Generated Auditory Noise on Rat Auditory Perception at 9.4T Conny Frauke Schmidt1, Bing Wen Zheng1, Steven Graham2, Xavier Golay1, 3 1Biomedical Sciences Institutes, Singapore, Singapore; 2National University of Singapore, Singapore, Singapore; 3National Neuroscience Institute, Singapore, Singapore

This study investigated the effects of acoustic scanner noise on auditory perception and processing in the rat. Using a steady-state clustered-sparse temporal acquisition (ssCTA) protocol that allowed 'silent' fMRI scanning we avoided interference with acoustic noise which is produced by the scanner during echo planar imaging (EPI), similar to the spare-temporal designs employed in human auditory fMRI studies. We then introduced 4-s acoustic “EPI-like” stimuli to examine the effects of acoustic scanner noise on auditory perception.

14:30 3572. Auditory Selectivity for Species and Self Recognition in the Zebra Finch Brain: New Insights from Spin-Echo BOLD FMRI Colline Poirier1, Tiny Boumans1, Marleen Verhoye1, 2, Jacques Balthazart3, Annemie Van der Linden1 1Bio-Imaging Lab, Antwerp, Belgium; 2Vision Lab, Antwerp, Belgium; 3Ctr. Cell. Molec. Neurobiology, Belgium

2006-... Post-doc position in Bio-Imaging Lab, University of Antwerp, Belgium (auditory fMRI in zebra finches)2005: PhD in Neurosciences, GREN laboratory, University of Louvain, Belgium ( PhD thesis: Auditory perception and sensory substitution: a neuro-ethological approach.2000: Master in Behavioral biology, University of Paris13/University of Rennes1 (Master thesis: Effects of social experience on song learning in starlings).

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15:00 3573. Functional MRI of the Rat Spinal Cord in Painful Diabetic Neuropathy Cheryl Jones1, Paul Fernyhough2, Nigel Calcutt3, Krisztina Laura Malisza4 1University of Winnipeg, Winnipeg, Canada; 2University of Manitoba, Winnipeg, Canada; 3UCSD, La Jolla, USA; 4National Research Council Institute for Biodiagnostics, Winnipeg, Canada

This study shows that fMRI of the spinal cord has promise for the detection of early onset diabetic neuropathy. FMRI of the spinal cord was conducted in healthy controls and streptozotocin (STZ) diabetic rats using electrical and formalin stimulation. Greater fMRI activity was observed in STZ animals during 0.2% formalin injection and greater percentage signal change occurred in diabetic animals with both 0.2% and 5.0% formalin injection. This demonstrates the hypersensitivity in these animals. Less activity was observed in the dorsal horn during noxious electrical stimulation in STZ rats compared to controls, suggesting neuronal fibre dysfunction.

15:30 3574. Modality-Specific Frequency Dependency of the Rat Somatosensory Cortex Assessed by FMRI Basavaraju Ganganna Sanganahalli1, Peter Herman1, Fahmeed Hyder1 1Yale University, New Haven, Connecticut, USA

We investigated the frequency-dependent activation of the rat somatosensory cortex at 11.7T for two sensory modalities (whisker and forepaw). We observed linear increase in the BOLD response with increasing frequencies up to 12 Hz and showed saturation at higher frequencies during whisker stimulation. On the contrary the magnitude of BOLD response for forepaw stimulation was largest at 1.5 Hz and decreased with increasing frequencies. These results demonstrate differences in the frequency dependent behavior during forepaw and whisker stimulations and provide a model for studying coupling between neuronal activity and blood flow across the different somatosensory regions.

fMRI: Non-BOLD & MT Hall D Tuesday 13:30-15:30

13:30 3575. Volumetric Blood Flow Rate Measurement by Flow ENhancement of Signal Intensity (FENSI) Cheng Ouyang1, Dimitrios Karampinos1, John G. Georgiadis1, Brad P. Sutton1 1University of Illinois at Urbana-Champaign, Urbana, Illinois, USA

Blood flow changes are believed to be more directly related with brain activation than blood oxygenation techniques, especially flow in microvessels (arterioles, capillaries, and venules). In this work, we applied the method Flow ENhancement of Signal Intensity (FENSI) to measure quantitative information on microvascular volumetric flow rates at baseline level and during a functional visual task. Besides providing accurate measurements of blood flow, FENSI also possesses high spatial localization and directional sensitivity.

14:00 3576. Highly Conserved CBF/CMRO2 Coupling in Human Primary Visual Cortex for Chromatic and Luminance Stimuli Oleg Leontiev1, 2, Giedrius T. Buracas2, Christine Liang2, Joanna E. Perthen2, Beau M. Ances2, Richard B. Buxton2 1Exempla St.Joseph Hospital, Denver, Colorado , USA; 2University of California, San Diego, La Jolla, California , USA

We conducted a systematic set of experiments designed to optimize the sensitivity for detecting a difference in CBF/CMRO2 coupling to criticially test the hypothesis of uniform coupling for chromatic and luminance stimuli in human primary visual cortex (V1). CBF/CMRO2 coupling in V1 was very similar for the chromatic and luminance stimuli used, suggesting a consistent coupling for Cytochrome-oxidase (CO) blob and inter-blob regions despite differences in CO concentration.

14:30 3577. Dependence of Functional ASL MRI Signal on Number of Slice Acquisitions Ajna Borogovac1, John W. Krakauer, Truman R. Brown, Iris Asllani 1Columbia University, New York, New York, USA

We present experimental data from motor stimulation showing a dependency of ASL functional SNR on the number of acquisition slices. Both resting and activation group-average CBF values were higher for partial coverage as compared to the whole brain acquisition. Also, the number of activated voxels was ~50% higher for the smaller imaging volume. However, whole brain acquisition showed a more complete localization of activation by detecting areas in the cerebellum associated with motor stimulation.

15:00 3578. Implicit Learning–related Effects Detected by Optimized ASL FMRI María A. Fernández-Seara1, Maite Aznárez-Sanado1, Francis Loayza1, Maria A. Pastor1 1Center for Applied Medical Research, University of Navarra, Pamplona, Spain

An optimized ASL technique was used to study changes in neural activity with motor learning. This sequence combines pseudo-continuous labeling with a background suppressed single shot 3D GRASE readout. The increased sensitivity of the sequence allowed detection of implicit learning effects at the group level.

13:30 3579. Quantification of Cerebral Blood Volume During Brain Activation with Grey Matter Nulled FMRI Yuji Shen1, Ida Mengyi Pu2, Risto A. Kauppinen3 1University of Birmingham, Birmingham, UK; 2Goldsmiths, University of London, London, UK; 3Dartmouth Medical School, Hanover, USA

Grey matter nulled (GMN) fMRI is a new fMRI technique that reveals changes in CBV associated with brain activation. The GMN fMRI is prone to errors in estimation of absolute CBV due to partial volume effect of CSF. In this study, we present a technique to quantify CBV both in baseline and during activation by determining CSF fraction in MRI voxels. A set of GMN fMR images was acquired with multiple TRs to fit data into a model comprising of multiple parenchymal compartments. CBV at baseline and during visual stimulation was found to be 5.5±0.04 and 7.8±0.08 ml/100 ml, respectively.

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14:00 3580. Simultaneous Acquisition of BOLD and VASO Signals Using Looker-Locker Method Wen-Chau Wu1, 2, Felix W. Wehrli2 1National Taiwan University, Taipei, Taiwan; 2University of Pennsylvania, Philadelphia, USA

In this study, we use the Look-Locker (LL) sequence to simultaneously measure BOLD and VASO signals during epochs of visual stimulation. LL images were binned by TI and analyzed separately, which led to ten sets of time series data (L1,L2,...,L10), each with a temporal resolution of 4 s. The varied weighting of BOLD and VASO signals at different TI's may help understanding of VASO signal source and extra- vs. intra-vascular BOLD. Flow information may be extracted by modeling the signals at L10 versus L1.

14:30 3581. Enhancing Relative BOLD Signal Changes Using Magnetization Transfer (MT) Jun Hua1, Manus J. Donahue1, Seth A. Smith1, Peter C.M. van Zijl1, Jinyuan Zhou1 1Johns Hopkins University School of Medicine, Baltimore, Maryland, USA

We show that the BOLD signal change can be increased by adding an off-resonance MT pre-pulse to the BOLD sequence that suppresses the pure tissue signal. This is due to an increase in the relative contribution from blood (intravascular BOLD). The relative enhancement ranges from 30% to 50%. Thus MT-BOLD can employ a shorter TE than normal BOLD with comparable contrast to noise ratio. The relative signal changes from a pair of MT-BOLD and BOLD experiments can be used to calculate the extravascular contribution to the BOLD effect, which was found to be 65%±8% at a field strength of 3T.

15:00 3582. Using Magnetization Transfer (MT) to Enhance SNR and CNR for VASO MRI Jun Hua1, Manus J. Donahue1, Jason M. Zhao1, Ksenija Grgac1, Alan J. Huang1, Jinyuan Zhou1, Peter C.M. van Zijl1 1Johns Hopkins University School of Medicine, Baltimore, Maryland, USA

Vascular Space Occupancy (VASO) fMRI employs tissue signal changes during blood nulling to image blood volume changes. It has low tissue SNR due to the small remaining tissue signal (10-20% of normal). We show here that adding an MT pulse before or after the VASO inversion pulse can attenuate the initial tissue magnetization before inversion or accelerate the recovery process after inversion, respectively. This leads to increased tissue signal intensity at the time of blood nulling, drastically improving SNR (~50% and 40%, respectively). Since relative VASO signal changes are unchanged, the CNR can be enhanced by ~45% and 35%, respectively.

fMRI: Neuroscience Hall D Tuesday 13:30-15:30

13:30 3583. Cerebral Response to Different Voice Production: A Functional Magnetic Resonance Imaging Study Kyung K. Peck1, Jessica Galgano, Ryan Branski, Merge Ho, Andrei Holodny, Dennis Kraus1 1Memorial Sloan-Kettering Cancer Center, New York, USA

The neural correlates of laryngeal movement for voice production at comfortable as well as other pitch levels remain poorly characterized. This is due, in part, to difficulties controlling for experimental confounds between the sensorimotor and cognitive-linguistic aspects of speech phonation/voicing. Thus, investigations aiming to isolate the neural mechanisms of voice production, and in particular, pitch modulation, can be a particular challenge. The current study seeks to describe the central mechanisms responsible for voice production in healthy subjects using functional magnetic resonance imaging (fMRI).

14:00 3584. The High Incidence and Bioethics of Findings on MR Brain Imaging of Normal Volunteers for Neuroscience Research Nigel Hoggard1, Gail Darwent1, David Capener1, Iain Wilkinson1, Paul Griffiths1 1University of Sheffield, Sheffield, UK

Over the past decade there has been a huge expansion of interest in functional MR imaging of the brain for neuroscience research and it is capturing the interest of the general public. Illes has estimated that between 1991 and 2000 using fMRI as the keyword search that there may have been at least 30000 research participants in fMRI studies in the published literature. We have found a high rate of incidental abnormalities (8.8%) amongst individuals participating in imaging studies at our institution. We believe that in medical research imaging a there is a duty of care to the participants and that neuroradiological review should be performed and if sugnificant pathology discovered the participant should be informed, counselled and their primary care physician informed to allow the participant to be able to discuss findings over time and recieve advice independent of the research team.

14:30 3585. Judgment of Moral Certainty: Developmental FMRI Patterns Melissa Ann Long1, Paul Joseph Eslinger1, Jianli Wang, Jennifer Realmuto, Fernanda Moll, Jorge Moll, Qing Yang 1Penn State College of Medicine, Hershey, Pennsylvania, USA

Moral judgment (MJ) is defined as the capacity to make decisions and judgments which are moral and to act in accordance with such judgments (Kholberg 1964). MJ is crucial in guiding social behavior. A better understanding of MJ and its development will be innovative in promoting MJ’s that foster pro-social emotions and behavior and attenuate anti-social emotions and behavior, which are the root of numerous social disorders/diseases and their associated pain, diminished quality of life, and vulnerability to criminal behavior (Stams et al. 2006). Several adult fMRI studies have investigated MJ in the brain, but none to our knowledge, have investigated MJ and its development in children. Utilizing fMRI, we conducted an experiment demonstrating the neural uderlyings of children's responses to sentences that contained moral content and were chosen by the child to be either "right" or "wrong." Resulting brain activations patters indicated that most acitvations were similar to that of adult studies. Areas of activation were in the frontal regions and the posterior temporal regions of the brain.

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15:00 3586. Analysis of the Effect of Magnetic Fields on the Amplitudes of the Early and Late Cognitive Potentials During FMRI Sirel Karakas1, 2, Hakki Muammer Karakas, 23, Zeynel Baran1, 2, Arzu Ozkan-Ceylan1, 2, Elvin Dogutepe-Dincer1, 2, Turgut Tali, 24 1Hacettepe University, Ankara, Turkey; 2Turkish Multicenter Research Group on Cognitive Neurosciences, (TURCONS), Turkey; 3Inonu University, Kampüs, Turkey; 4Gazi University, Turkey

MRI-EEG studies provides simultaneously recorded structural, hemodynamic and electrophysiological data. The aim was to investigate the magnitude of the contaminating ballistocardiogram artifact during fMRI recording on specifically the earlier ERP component and to provide information on the reliability of MRI-EEG technique. A 1.5 T scanner with high resolution coil, coupled with MR-compatible 64-channel EEG and stimulation hardware was used. The study showed that the early and late peaks on the ERP were comparably obtained in standard EEG lab and in the scanner. The previously reported attenuation of some ERP peaks was found to be the result of inter-individual latency jitter.

13:30 3587. Effect of Intravenous Lidocaine on Brain Activation During Non-Noxious and Acute Noxious Stimulation of the Forepaw: A Functional MRI Study in the Rat Zhongchi Luo1, Mei Yu1, S, David Smith2, Mary Kritzer1, Yu Ma1, Congwu Du1, Nora D. Volkow3, Peter S. Glass1, Helene Benveniste, 12 1Stony Brook University, Stony Brook, New York, USA; 2Brookhaven National Laboratory, Upton, New York, USA; 3NIH, Bethesda, Massachusetts, USA

We investigated the analgesic action of systemic lidocaine on the brain's responses to acute pain. We showed that its action is not related to a straight forward interruption of pain-induced brain activation as has been observed with opioids. We also found that lidocaine enhanced cortical responses to acute pain similar as what has been reported for cocaine. We recently showed that both lidocaine and cocaine increased intracellular calcium concentrations in cortex suggesting that this pharmacological effect could account for the enhanced sensitivity to somatosensory stimulation. As our model only measured physiological acute pain it will be important to also test the response of these same pathways to lidocaine in a model of neuropathic pain to determine lidocaine’s analgesic mechanism of action.

14:00 3588. Reproducibility and Sensitivity of Pain-Related FMRI-BOLD Activation Responses Due to Noxious Nd:YAP Laser Stimulation: A Possible Tool for Analgesic Drug Discovery Catherine Elizabeth Warnaby1, Ricardo Jose Governo1, Iain Robert Wilson1, Paul M. Matthews2, 3, Irene Tracey1 1University of Oxford, Oxford, UK; 2GlaxoSmithKline, London, UK; 3Imperial College, London, UK

A parametric laser-FMRI study was performed to investigate the sensitivity and reproducibility of BOLD responses to pain-related brain activity. During three experimental sessions, laser stimuli were delivered at intensities corresponding to the individual’s perception of low, medium and high pain. Subjective pain ratings were recorded after each stimulus and despite non-significant changes in pain ratings across sessions the FMRI was sensitive enough to detect significant differences that correlated with minor non-significant changes in pain ratings. Early results suggest that BOLD-FMRI can potentially provide a more objective and robust marker of pain perception than the subjective pain report.

14:30 3589. Studying Pain Transmission with BOLD FMRI: Thermal vs. Electrical Stimulation Arthur Peter Wunderlich1, Gregor Stuber1, Roland Klug2, Wolfgang Freund1 1Univ.-Clinic Ulm, Ulm, Germany; 2Rehabilitation Clinic Ulm, Ulm, Germany

In order to study the feasibility to distinguish different pathways of pain transmission, we acquired 15 healthy subjects each for thermal and electrical stimulation. During fMRI, subjects were stimulated in blocks of three different intensities and no stimulation as reference condition in pseudorandomized order. Attention of subjects was focused to sensation advising them to rate stimulus intensity. Data were analysed in SPM. Contrasts of all intensities against rest were calculated and compared between both modalities in a second-level analysis. Differences in cortical and subcortical activation were found, which can be interpreted as consequence of different pathways activated by stimulus modalities.

15:00 3590. Semantic Memory in the Anterior Temporal Lobes: A New Distortion Correction Method for FMRI Maya Visser1, Karl Victor Embleton1, Elizabeth Jefferies1, 2, Geoff J. Parker1, Matthew A. Lambon Ralph1 1University of Manchester, Manchester, UK; 2University of York, York, UK

The neural substrate of semantic memory is a topic of considerable debate. Patients with semantic dementia show a highly specific impairment of semantic memory, associated with atrophy in the anterior temporal lobes (ATL) bilaterally, suggesting that this is the critical neural substrate for semantic memory. However, most fMRI studies do not observe ATL activation during semantic processing because the signal is distorted and/or suppressed in these areas. We used a new distortion correction for fMRI to investigate brain activation during semantic processing. This method revealed bilateral ATL activation during semantic processing, providing convergence with evidence from patients with semantic dementia.

13:30 3591. Identical Stimuli But Different Cortical Activations: FMRI Study on Active and Passive Oddball Tasks Hakki Muammer Karakas1, 2, Sirel Karakas, 23, Turgut Tali, 24 1Inonu University, Kampüs, Turkey; 2Turkish Multicenter Research Group on Cognitive Neurosciences, (TURCONS), Turkey; 3Hacettepe University, Ankara, Turkey; 4Gazi University, Ankara, Turkey

Cognitive requirements of the passive oddball paradigm task is auditory memory and preattentional change detection. On the other hand, the cognitive requirements of the active oddball paradigm task include these three processes and also focused attention, working memory, stimulus recognition and decision for the response to be made. This fMRI study was conducted to reveal differential activation caused by these tasks. They both produced activation in auditory cortex and its vicinity. However, only the active oddball task led to activation in the general integration area and in the frontal lobes, an event that cannot be detected with electrophysiological methods.

14:00 3592. Modulation of Human Mirror Neuron System by Task Complexity and Laterality Michela Tosetti1, Andrea Guzzetta1, Laura Biagi1, Elisa Petacchi1, Serena Galiberti1, Leonardo Fogassi2, Giovanni Cioni1, 3 1Stella Maris Scientific Institute, Pisa, Italy; 2University of Parma, Italy; 3University of Pisa, Pisa, Italy

We studied the Mirror Neuron circuit in twelve right-handed healthy volunteers. The anterior intraparietal cortex was activated by the observation of external actions according to the identity of the observed hand and to the complexity of the hand action. These findings support the hypothesis of a specific role of anterior intraparietal cortex in the final steps of visuo-motor transformation.

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14:30 3593. Brain Activation Associated with Subliminal Reading Stimuli in Dyslexics and Normal Readers – an FMRI Study Tammar Kushnir1, Shani Fishman1, David Manor1, 2 1The Chaim Sheba Medical Center, Tel Hashomer, Israel; 2Haifa University, Haifa, Israel

Compatibility effect (CE) is a modulation of the motor response time to a target stimulus by a preceding prime stimulus that is either compatible or incompatible with the target stimulus. CE has been found for subliminal masked prime. The present study investigated CE on behavioral and associated brain activity in dyslexic and non dyslexic subjects, using a subliminally priming reading stimulus. The brain activity was evaluated using functional MRI (fMRI). Behavioral and brain activity results indicated that CE and the perception and processing of a subliminal stimulus in the right hemisphere were stronger in the dyslexic subjects.

15:00 3594. Task Difficulty Differences with Age in a Functional MRI Verb Generation Task Mayuresh S. Korgaonkar1, Susan Fiore1, Candice J. Perkins1, Nancy K. Squires1, Zengmin Yan1, Mark E. Wagshul1 1Stony Brook University, Stony Brook, New York, USA

Previously, we have shown that subject-specific categorization of task difficulty can be used to identify differential recruitment in the standard language areas with change in difficulty, using a verb generation fMRI task. The goals of this study were: 1. to evaluate the differences in functional recruitment with task difficulty, between younger and older subjects, and 2. to quantify between group and between individual variability of activation with task difficulty. Of particular interest is the quantification of individual subject task difficulty, which has specific implications for studying brain plasticity in patients where population-based inferences are less important.

fMRI: Connectivity & Networks Hall D Wednesday 13:30-15:30

13:30 3595. Correlation Modulation Networks to Assess Changes in Functional Connectivity with Task Difficulty Mayuresh S. Korgaonkar1, Susan Fiore1, Candice J. Perkins1, Nancy K. Squires1, Zengmin Yan1, Mark E. Wagshul1 1Stony Brook University, Stony Brook, New York, USA

Correlation modulation network analyses allow the evaluation of condition specific functional interactions between brain regions. Our previous results show that there is differential recruitment of brain regions in a task difficulty modulated verb generation task. Using the correlation modulation approach, we sought to evaluate the following: 1. If the connectivity between language regions is modulated by experimental conditions – particularly between generating verbs as compared to passive viewing of non-words and difficult as compared to easy to generate verbs; and 2. How these condition-specific modulations of connectivity differ between young and old subjects.

14:00 3596. Effect of Hemodynamic Spatial Variability on Granger-Based Long Term Causality Gopikrishna Deshpande1, George Andrew James1, Xiaoping Hu1 1Georgia Institute of Technology and Emory University, Atlanta, Georgia, USA

Causal relationships between cortical regions can be inferred from fMRI using Granger causality (GC). However, GC may be affected by spatial variability of the hemodynamic response (HRF). We examine the effect of HRF variability on the causal influences in a neural network that evolves slower than the HRF variability and TR. Simulations showed that the HRF variability leads to erroneous results. Furthermore, we show that the true causality could be recovered by using summary measures derived from the BOLD data instead of the raw fMRI time series. These findings are illustrated using data obtained from a fatigue motor task.

14:30 3597. Network Reduction for Interpreting Large Scale Brain Networks Gopikrishna Deshpande1, Randall Stilla, Krish Sathian, Xiaoping Hu1 1Georgia Institute of Technology and Emory University, Atlanta, Georgia, USA

In this work, we illustrate the utility of multivariate Granger causality analysis for characterizing large brain networks and introduce a new procedure for removing unimportant nodes while retaining the important ones in the network. This method was applied to tactile perception fMRI data which demonstrated the co-existence of top-down and bottom-up mechanisms in tactile perception.

15:00 3598. Localization of the Language Network Using Resting State Functional Connectivity MRI and Diffusion Tensor Tracking Joshua S. Shimony1, Adrian A. Epstein1, S Neil Vaishnavi1, Mark W. Sansbury1, Jeff G. Ojemann2, Abraham Z. Snyder1, Marcus E. Raichle1 1Washington University School of Medicine, St. Louis, Missouri, USA; 2University of Washington School of Medicine, Seattle, Washington, USA

Although the language network is localized around the left sylvian fissure in a great majority of the population, there is a significant amount of variability in localization between individuals. Localization in individuals is of great interest for pre-surgical planning to help decrease the morbidity from left temporal lobe surgery. The purpose of this project was to study the variability of the language network in individuals and to validate its localization by correlating the results using a functional method, resting state functional connectivity MRI, and an anatomic method, diffusion tensor tracking.

13:30 3599. Discrepencies Between Functional Connectivity Measured with BOLD and CBF in Major Depressive Disorder Richard Cameron Craddock1, Christopher B. Glielmi2, Paul E. Holtzheimer3, Xiaoping P. Hu2, Helen S. Mayberg 1Georgia Tech, Atlanta, Georgia, USA; 2Georgia Tech and Emory University, Atlanta, Georgia, USA; 3Emory University, Atlanta, USA

Functional connectivity was compared between CBF and BOLD for networks associated with depression. Overall there was consensus with striking differences.

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14:00 3600. Spatially Independent Component Analysis for Automatically Delineating Brain Functional Connectivity with Resting-State FcMRI Quan Zhu1, Chung-Yi Yang2, Eldom Toh3, John H. Gilmore3, Weili Lin3 1Duke University, Durham, North Carolina, USA; 2National Taiwan University Hospital, Taiwan; 3University of North Carolina at Chapel Hill, Chapel Hill, USA

In this work, automatic procedures were developed to determine the components that most likely reflect brain functional connectivity for resting-state fMRI images using spatial independent component analysis (sICA). The developed approaches were then utilized to depict cortical connectivity in neonates (2-4wks), one-year and two-year old children.

14:30 3601. Detecting Direct and Indirect Functional Connections Using Granger Causality Zhenyu Zhou1, 2, Yonghong Chen1, Guojun He1, Paul Wright1, Mingzhou Ding1, Yijun Liu1 1University of Florida, Gainesville, USA; 2Southeast University, Nanjing, People's Republic of China

An analysis approach that based on the Granger causality method is proposed to study the directional effective influence between brain regions in fMRI data. Granger causality was employed to extracted BOLD signals to investigate effective connectivity in the brain network. Data from an emotion task were used to validate this method, and the emotion pathway was clarified illustrated focus on the right amygdala. The presented results, exploring directional influences between activated brain regions, indicated that the Granger causality mapping combined with principal component analysis could improve existing applications of traditional pairwise Granger causality mapping method in human brain connectivity studies.

15:00 3602. A Comparison of the Abilities of Structural Equation Modeling, Autoregressive Analysis, and Granger Causality to Detect Path Weight Differences in Effect Connectivity Results Calculated from Real FMRI Time Series Data Suzanne Theisen Witt1, M Elizabeth Meyerand1 1University of Wisconsin, Madison, Wisconsin, USA

Structural equation modeling (SEM), autoregressive analysis (AR), and Granger causality (GC) are three commonly used methods for calculating effective connectivity from fMRI data. A comparison of these methods’ abilities to detect differences in path weights between two different simple motor tasks is presented. The results of the comparison suggest that, although the path weights estimated using SEM exhibit a much larger dynamic range than those obtained using AR and GC, these latter two methods may be as good or better than SEM at detecting path weight differences.

13:30 3603. The Effects of Time Length on Resting-State Functional Connectivity Jun Xie1, Gao-Hong Wu1, Shi-Jiang Li1 1Medical college of Wisconsin, Milwaukee, USA

In this study, we investigated the effects of time length on resting-state functional connectivity. EPI data were acquired at 3T in 10 resting normal subjects. The patterns of motor cortex connectivity were compared using different scan time lengths. Our data suggest that about 400 second scanning provides the best tradeoff between the quality of connectivity map and scan time.

14:00 3604. Spatiotemporal Dynamics of Low Frequency Fluctuations in BOLD FMRI of Rats Waqas Majeed1, Matthew Magnuson1, Shella Keilholz1 1Georgia Institute of Technology / Emory University, Atlanta, Georgia, USA

This abstract presents:1) Spatial patterns evolving over time in low frequency BOLD fluctuations in rat cerebral cortex2)Preliminary classification of these fluctuations into different 'states'

14:30 3605. Measuring Connectivity in Sensory Cortex Using an FMRI Adaptation Paradigm Laura M. Parkes1, Rishma Vidyasagar1, Stephen Folger2 1University of Liverpool, Liverpool, UK; 2Elon University, USA

fMRI adaptation paradigms probe neural activity on a millisecond timescale. We investigate whether this approach can be developed to measure ‘connectivity’ between two regions in the somatosensory cortex. Paired vibrotactile pulses are given to digits 2 and 4 at intervals of 50, 200 and 400ms. A reduction in BOLD amplitude is seen in all subjects at 200ms compared to 50ms and 400ms. This could be due to the first pulse inhibiting neighbouring regions, reducing excitability, and so reducing the response to the second pulse. This demonstrates a method of directly measuring the influence and timing of interactions between sensory regions.

15:00 3606. The Anatomical Basis of Rest Functional MRI Aviv Mezer1, Yossi Yovel1, ofer Pasternak1, Tali Gorfine1, yaniv assaf1 1Tel Aviv University, Tel Aviv, Israel

Basal activity measured with fMRI raised tremendous interest among neuroscientists since functional brain activity could be retrieved while the subject rests (resting state fMRI). We show here that the basis of the resting-state fMRI signal – the blood oxygenation level dependent (BOLD) contrast – has a strong anatomical basis in addition to its functional components. We found high similarity between the clusters of the repeated BOLD measures and atlas segmentation. We suggest that multi-dimensional brain MRI acquisition can be used for parcellation of the brain into regions that could not be extracted with conventional MRI.

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fMRI: ICA & Clustering Analysis Hall D Wednesday 13:30-15:30

13:30 3607. Independent Vector Analysis for Group FMRI Processing Jong-Hwan Lee1, Matthew Marzelli1, Ferenc A. Jolesz1, Seung-Schik Yoo1 1Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA

We propose to develop an independent vector analysis (IVA) scheme to address the permutation problem of the conventional ICA-based group processing scheme. IVA operates to increase independence across output vector components while maintaining dependence among scalar elements within each output vector component (i.e. across frequency bins within the same output index). The ¡®dependence¡¯ in group fMRI processing is analogous to mutual/similar activation patterns across subjects, which are comparable to the group trend in activation.

14:00 3608. A Method for Group Difference Enhancement by Constraining Mixing Coefficients of ICA Framework Jing Sui1, Vince Calhoun1, 2 1The Mind Research Network, Albuquerque, USA; 2University of New Mexico, Albuquerque, USA

We proposed a novel algorithm called CCICA (constrained coefficient ICA) by incorporating prior statistical group information as constraint into the general ICA framework. Our algorithm improved the capability for identifying the independent component showing the largest group difference related to the mixing coefficients. Applications to both hybrid and real fMRI data demonstrate that CCICA is a promising method for identification of components that can best distinguish schizophrenia patients and healthy controls, and further, it may be more sensitive for extracting features that can serve as potential brain imaging biomarkers of disease.

14:30 3609. Assessing Reliability of ICA Estimates by Resampling and Clustering Radu Mutihac1 1University of Bucharest, Bucharest, Romania

Analysis of artificially generated fMRI-like data drawn from a single-shot gradient-echo MR EPI block-based visual stimulation paradigm was performed by the stochastic neuromorphic extended Infomax algorithm implementing spatial independent component analysis (sICA). Reliability assessment of the results was carried out by resampling-based techniques and clustering. Fourier and wavelet transforms, which contain weak implicit models of temporal noise, and whitening, which is driven by an explicit noise model, were employed to resampling and setting the appropriate thresholds. Variance estimate that is highly correlated with the separation error was used as model selection criterion for optimizing the parameters of the sICA algorithm.

15:00 3610. fMRI Clustering Based on Connectivity Profiles samuel emeriau1, 2, Fabien Giersky3, Laurent Pierot3, Eric Bittar1 1Université de Reims Champagne-Ardennes, Reims, France; 2Philips Systèmes Médicaux, Suresnes, France; 3University Hospital of Reims, Reims, France

fMRI clustering based on connectivity profiles offers two major advantages in comparison with the classical clustering method: it allows dealing with the problem of spatial correlation of noise that can lead to bad mergings in functional domain and it allows defining a new functional dimension exclusively based on the data without taking the paradigm into account trough specified regressors. The resulting clusters form a partition of the data in homogeneous regions according to both spatial and functional connectivity points of view.

fMRI: Mechanisms Hall D Thursday 13:30-15:30

13:30 3611. Investigating the Source of BOLD Nonlinearity Nanyin Zhang1, Xiao-Hong Zhu1, Wei Chen1 1University of Minnesota, Minneapolis, Minnesota, USA

The nonlinear effects in BOLD signal have posed a serious problem in rapid ER fMRI designs. To solve this problem, detailed investigation of the source of BOLD nonlinearity is essential. However, little effort has been spent in separating the potential source of neuronal activity attributing to the nonlinearity observed in BOLD data. The obscurity in this issue seriously impedes accurate modeling of BOLD nonlinearity. Therefore, to find the originality of the BOLD nonlinearity, we have employed a paired-stimulus paradigm in absence of neuronal refractoriness and measured the corresponding BOLD responses. The results indicate that the BOLD nonlinearity can completely be vascular origin.

14:00 3612. Transient and Steady-State Components of the FMRI BOLD Signal in Somatosensory Cortex Michael Marxen1, Tara L. Dawson1, Fred Tam1, Simon J. Graham1, 2 1Baycrest Centre for Geriatric Care, Toronto, Canada; 2University of Toronto, Toronto, Canada

Previous MEG studies have demonstrated transient and steady-state evoked reponses to vibrational touch stimuli to a finger with spatially separated dipole locations in primary somatosensory cortex. The goal of this study is to extract transient and steady state components from the fMRI BOLD response to repeated vibrational stimuli of different durations. In the first three subjects of an ongoing larger study, we found differences in the transient and steady-state activation maps that may reflect transiently and continuously firing neuronal populations. A paired comparison with MEG transient and steady-state dipole locations is in progress.

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14:30 3613. Steady-State to Transient Change of CMRO2: Dynamic Calibrated FMRI at 11.7T Basavaraju Ganganna Sanganahalli1, Peter Herman1, Fahmeed Hyder1 1Yale University, New Haven, Connecticut, USA

We studied the relationship between fMRI BOLD, evoked CBF and the electrical activity of neuronal origin. The BOLD, CBF, CBV and LFP were examined in experiments where the number of the stimuli (2mA, 0.3ms) at rat forepaw was increased from one to four with varying inter pulse interval (IPI) of (167ms, 333ms, 666ms). We found variable dependencies of each measured component (BOLD, CBF, CBV, LFP) with IPI. We found that CMRO2 contributed to BOLD even with IPI of less than 200 ms (i.e., 6 Hz). These results suggest that BOLD at high field (of 11.7T) has sensitivity to reveal a significant CMRO2 component for extremely short events

15:00 3614. Assessment of the Significance of Temporal Delays in the BOLD Signal Response to a CO2 Stimulus julien poublanc1, Jay Shou Han2, Danny Michael Mandell1, Jeffrey A. Stainsby3, Joseph A. Fisher4, David J. Mikulis1, Adrian P. Crawley1 1Toronto Western Hospital, Toronto, Canada; 2Toronto General Hospital, Toronto, Canada; 3GE Healthcare, Toronto, Canada; 4Toronto General Hospital , Toronto, Canada

Cerebrovascular reactivity imaging combines BOLD MRI with inhaled CO2 to measure brain’s autoregulatory capacity. Although the magnitude of the BOLD signal is primarily employed to assess reactivity, the temporal delay of the BOLD response contains useful information, investigated in this study. We calculated a time delay parameter that significantly correlates with the reactivity parameter, as well as with the time to minimum of the dynamic susceptibility contrast images. We have also observed that the main time delay occurs not on onset of hypercapnia but arises from a late return to baseline after the ETpCO2 has already decreased.

13:30 3615. Quantifying the FMRI BOLD Signal to Characterize the Event-Related Electrophysiological Response Zhongming Liu1, Bin He1 1University of Minnesota, Minneapolis, Minnesota, USA

In the present theoretical study, we establish a linkage between the quantified BOLD effect size and the event-related electrophysiological response. Based upon an assumed linear neurovascular coupling, the BOLD effect size at each voxel can be explicitly interpreted as proportional to the time integral of the power of the event-related local synaptic current flow. This relationship contributes to a more rigorous theoretical framework for fusing fMRI and EEG/MEG, which leads to an advanced high-resolution multimodal neuroimaging technique.

14:00 3616. Towards a Quantitative Relationship Between the BOLD Signal and Deoxyhemoglobin Measured by Near-Infrared Spectroscopy Dharmesh R. Tailor, MD, PhD1, Yu Chen, PhD, Ravinder Reddy, PhD 1University of Pennsylvania, Philadelphia, Pennsylvania, USA

A quantitative relationship is established between the gradient-echo and the spin-echo based BOLD signal and the deoxyhemoglobin concentration measured by near-infrared spectroscopy in the rat brain. This approach provides a more direct means of calibrating the BOLD signal using the recently proposed hyperoxia approach. Furthermore, spin-echo based methods are shown to be sensitive not only to dissolved oxygen but also to deoxyhemoglobin directly. Additionally, spin-echo based T1?-weighted imaging in demonstrated in humans to yield detectable signal changes due to a change in fraction of inspired oxygen.

14:30 3617. Baseline Cerebral Blood Flow Modulates Functional Perfusion Activation Maps But Not BOLD Activation Maps Joy Liau1, Joanna Perthen1, Thomas T. Liu1 1University of California at San Diego, La Jolla, California , USA

This study examines the dependence of functional perfusion or cerebral blood flow (CBF) and BOLD activation maps on baseline CBF. We used a caffeine dose (200mg) to reduce the baseline CBF and found concurrent decreases in the activation map area based on the CBF response but not the BOLD response. Also, measures of baseline CBF accounted for a significant portion of the inter-subject variability in CBF activation map area. Factors that can modulate baseline CBF, such as age, medication, and disease, should therefore be carefully considered in the interpretation of studies that use functional CBF activation maps.

15:00 3618. Strong Correlation of Spin-Echo BOLD Signal with Neuronal Activity in Rat Cortex During Forepaw Stimulation Ikuhiro Kida1, Toru Yamamoto1 1Hokkaido University, Sapporo, Japan

The relation between signal in neuroimaging techniques and the neuronal activity is essential to investigate brain function. However, the correlation of the BOLD signals with neuronal activity is still unclear. We investigated whether the spin-echo (SE) BOLD signal correlates with neuronal activities during rat forepaw stimulation with various stimulus currents and frequencies (0.5-2.0 mA and 1-10 Hz). We found that the SE-BOLD signal linearly increases with the integration of somatosensory evoked potential amplitude for all stimulus conditions. This result indicates that the SE-BOLD signals may elucidate the neural activity quantitatively.

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fMRI: Multimodal & Single Trial Hall D Thursday 13:30-15:30

13:30 3619. Retrospective Synchronization (Resync) Avoids the Residual MRI Gradient Artefact in EEG-MRI Experiments Hendrik Mandelkow1, Pascal Halder2, Daniel Brandeis2, Peter Boesiger1 1University and ETH Zurich, Zurich, Switzerland; 2University of Zurich, Zurich, Switzerland

We present a new software synchronization method which improves the post-processing of EEG-fMRI data for the purpose of removing the notorious MRI gradient artefact. Furthermore, we propose a new procedure for quantifying and comparing the cleaning performance of different post-processing algorithms for EEG-fMRI data. The comparison based on in-vivo data as well as simulations of the MGA at high bandwidth shows that the retrospective synchronisation algorithm can improve or even replace hardware synchronisation as well as other post-processing methods such as slice timing correction and PCA.

14:00 3620. Comparison of SQUID and MR Detection for Weak Magnetic Fields Martyn Paley1, Eugeny Krjukov1, LiSze Chow1 1University of Sheffield, Sheffield, UK

This study compares the sensitivity of a single channel SQUID and a 3T MRI system using phantoms and investigates axonal bursts in the median nerve using transcutaneous electrical nerve stimulation (TENS) stimulation using the SQUID.

14:30 3621. Simultaneous FMRI/CBV and EEG During Spike-Wave Seizures in WAG/Rij Rats Asht Mangal Mishra1, Damien John Ellens, Ulrich Schridde, 12, Joshua Ethan Motelow1, Michael J. Purcaro1, Fahmeed Hyder1, Hal Blumenfeld1 1Yale University School of Medicine, New Haven, Connecticut, USA; 2YMPI for Biological Cybernetics, Tübingen, Germany

In absence and other generalized seizure disorders, an abnormal electrical activity termed as spike-wave discharges (SWD) is observed by EEG. fMRI during SWD in humans and animal absence epilepsy models show both increases and decreases in BOLD signals. Here we show regional BOLD increases/decreases during SWD accompanied by CBV increases/decreases in nearly the same areas for anesthetized WAG/Rij rats. Further work will be needed to determine if regions of BOLD decreases during SWD represent vascular steal, a primary neuronal mechanism, or a defect in neurovascular coupling. These findings will be important for the interpretation of various fMRI signals in human absence epilepsy.

15:00 3622. Simultaneous Single Unit and BOLD FMRI Recordings D Aksenov1, Limin Li1, G Iordanescu1, Alice M. Wyrwicz1 1ENH Research Institute, Evanston, Illinois, USA

Brain hemodynamic functional signal and the corresponding neuronal activity are recorded in an awake, behaving rabbit at high fields.

13:30 3623. Detection of Single-Trial Events in BOLD FMRI Without Prior Stimulus Information Cesar Caballero1, Natalia Petridou1, Sue Francis1, Ian Dryden1, Li Bai1, Penny Gowland1 1University of Nottingham, Nottingham, UK

The aim of this work is to map in space and time the brain’s response to single stimuli without prior knowledge of stimulus timing. Detection of single-trial events in BOLD fMRI time series is a challenge especially in the presence of physiological and systematic fluctuations. Here, a procedure based on Wiener deconvolution is proposed to detect single-trial events with no prior information on stimuli timing. Automatic detection is carried out only assuming a general shape for the hemodynamic response function, and employing tissue-dependent noise characterization. This technique allowed identification of individual trials, and the spatiotemporal evolution of the BOLD response.

14:00 3624. Increased Statistical Power of in Event-Related Real-Time FMRI (ErfMRI) Using Individual Hemodynamic Response Functions: First Results at 3T and 7T Maurice Hollmann1, Tobias Moench1, Sebastian Baecke1, Michael Luchtmann1, Claus Tempelmann1, Joerg Stadler2, Johannes Bernarding1 1University of Magdeburg, Magdeburg, Germany; 2Leibniz Institute for Neurobiology, Magdeburg, Germany

Assumptions about the hemodynamic response function (HRF) are used as basis in many fMRI analysis methods. However, the variability of the HRF between subjects, and intra-subject between different brain regions may reduce the statistical power if this assumptions are improper. Acquiring more data to counteract this effect is generally not feasible in real-time fMRI. We analyzed the functional data in event-related real-time fMRI with individual region-based HRF estimates acquired during the experiment-session prior to the main measurement. Using individual HRF estimates instead of the SPM canonical HRF led to an improvement in the statistical significance by an average of 25%.

14:30 3625. Effects of High Field MR Scanner on Simultaneous EEG Data Quality for Single-Trial Discrimination Cheng-Yu Wei1, Robin I. Goldman1, Paul Sajda1, Truman R. Brown1 1Columbia University, New York, New York, USA

The emerging technology of recording simultaneous EEG/fMRI allows direct measuring and comparison of brain responses to stimuli. Being able to follow changes in attention, adaptation or habituation on a single trial basis by using single trial EEG data to reveal brain regions which correlate with variations in these should considerably advance our understanding of cognitive processing. The simultaneously recorded EEG at 3T, examined with power spectrum analysis were of high quality to allow these single-trial investigations. Quality Assurance tests confirmed that fMRI data, in terms of spatial and temporal SNR, was acceptably stable across time to carry out brain functional studies.

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15:00 3626. A Model Phantom for Investigating Concurrent EEG/fMRI Gerða Björk Geirsdóttir1, Matthew J. Brookes1, Karen J. Mullinger1, Winston X. Yan1, Peter Morris1, Richard W. Bowtell1 1University of Nottingham, Nottingham, UK

Simultaneous EEG/fMRI is a technique that makes functional imaging with high spatiotemporal resolution possible. However, artefacts induced in EEG recordings by the MR scanner make this challenging. The use of an EEG phantom to conduct simultaneous EEG/fMRI experiments provides a means for validating and improving artefact correction techniques, and for investigating possible sources of the observed artefacts. Here, two different types of saline loaded agar phantoms are described, a dipole phantom which enables measurements of signals with a specific time-course, and a flow phantom with an added aqueduct designed specifically to mimic blood flow.

Bone Hall D Monday 14:00-16:00

14:00 3627. Advantages of Isotropic Voxel Size for Classification of Trabecular Bone Struts and Plates in Micro-MR Images Branimir Vasilic1, Jeremy Magland1, Michael Wald1, Felix W. Wehrli1 1University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA

A new method, based on local inertial anisotropy, has recently been introduced to classify trabecular elements into rods and plates. It relies on a locally calculated tensor of inertia to estimate the class (rod/plate) to which each voxel in the image belongs as well as the orientation of the corresponding rod or plate. While the structure of trabecular bone is anisotropic and can be used to justify the use of high-resolution imaging with an anisotropic voxel size, we show here that images acquired with isotropic voxel size have advantages in faithfully representing the underlying structure of trabecular bone.

14:30 3628. On-Line Prospective Registration of Trabecular Bone MR Images for Longitudinal Examinations Chamith S. Rajapakse1, Jeremy Magland1, Felix W. Wehrli1 1University of Pennsylvania School of Medicine, Philadelphia, USA

In micro-MRI studies of trabecular bone designed to evaluate structural changes in response to therapeutic intervention, follow-up scan volumes do not typically align with the baseline data due to inaccuracies in patient positioning and scan prescription. These limitations can be overcome by incorporating prospective registration into the acquisition protocol. The technique is based on registering 3D localizer images, acquired prior to the high-resolution images, on-site with an algorithm relying on maximizing the correlation between baseline and follow-up localizers. In phantom and human subject studies it is shown that prospective registration yields very close matching between baseline and follow-up imaging volumes.

15:00 3629. Proton NMR Study of Transverse Relaxation of Rabbit and Rat Cortical Bone Henry H. Ong1, Suzanne L. Wehrli2, Felix W. Wehrli1 1University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA; 2NMR Core Facility, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA

The NMR signal from cortical bone results from protons in collagen as well as water in the Haversian system. Characterizing transverse relaxation behavior may provide insight into bone composition and architecture. Here, we calculated T2* and T2 components of rabbit and rat cortical bone specimens from bi-exponential fits of FIDs and CPMG signal decays. Both species showed a similar short T2* component arising from collagen. The rat showed a larger short T2 fraction, suggesting a smaller fraction of Haversian canals compared with rabbit. The majority of the bone signal is comprised of water with T2* and T2 values of 200-400us.

15:30 3630. Density, Structure and Texture Quantitation of Bone Trabeculae at 3.0 Tesla Gary Paul Liney1, Clare P. Bernard1, Chris M. Langton, Lindsay W. Turnbull1 1University of Hull, Hull, UK

1) To validate the use of bone volume fraction (BVF) derived from MRI as a surrogate measure of volumetric density. 2) To investigate the structural and textural relationships of bone trabeculae. 3) To compare imaging coils and sequences in terms of their ability to demonstrate these relationships in clinically relevant protocols, and to obtain an optimised protocol for in vivo acquisitions.

14:00 3631. A Distance Weighted Directional Gradient Method for Fully Automatic Bone Segmentation of Knee MRI Feng Huang1, Xiaoming Chen2, Deliang Ye1, Sarah Hertel3 1Invivo Corporation, Gainesville, Florida, USA; 2University of Florida, Gainesville, Florida, USA; 3Invivo Corporation, Pewaukee, Wisconsin, USA

Fully automatic knee segmentation is desired since it is both time- and cost-efficient. The widely adopted Chan-Vese (CV) model could be used to implement a fully automatic segmentation technique. However, direct application of CV model on knee segmentation has a difficulty in separating different bones (Femur, Tibia and Patella) since these bones have similar intensity level. In this study, a distance weighted directional gradient method is proposed to automatically separate these bones, and define masks for further bone segmentation. With this technique, different bones can be isolated and fully automatic bone segmentation can be achieved without using any prior shape information. The proposed method was tested on 14 data sets of knee MRI. Results show that the proposed location detection technique can always provide accurate bone locations.

14:30 3632. Accuracy in Trabecular Bone Structural Measurement from High-Resolution Images Acquired with GRAPPA-Based Parallel Imaging Ben Hyun1, Suchandrima Banerjee1, 2, Sharmila Majumdar1, 2 1University of California, San Francisco, San Francisco, California , USA; 2University of California, Berkeley, Berkeley, California , USA

High-resolution magnetic resonance images of the distal radius were acquired to assess the accuracy of bone micro-architecture measurements using GRAPPA-based parallel imaging. Unaccelerated and accelerated images were acquired then analyzed using 2D histomorphometric based analysis to assess image fidelity and reproducibility.

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15:00 3633. Comparison of Mechanical Properties of Trabecular Bone Derived from μMRI and μCT Chamith S. Rajapakse1, Jeremy Magland1, Suzanne L. Wehrli, X Henry Zhang2, X Sherry Liu2, X Ed Guo2, Felix W. Wehrli1 1University of Pennsyslvania School of Medicine, Philadelphia, USA; 2Columbia University, New York, USA

Studies have shown that prediction of bone strength can be improved by including structural properties in the analysis in addition to bone density. The aim of this work was to address to what extent mechanical properties of trabecular bone (TB), measured in terms of Young’s and shear moduli, derived from μ MRI, compare with those obtained by μ CT at high resolution. To answer this question TB samples were imaged using μ MRI and μ CT. The data indicate that mechanical constants correlate well between the two modalities and the correlation can be improved by correcting for the bone volume fraction mismatch between them.

15:30 3634. Investigation of Subchondral Bone Cysts and Cartilage Defects Using in Vivo 9.4T MRI in a Model of Osteoarthritis David D. McErlain1, 2, Joe S. Gati, 2, Vasek Pitelka, 2, Jeffrey Mason, 2, Rob Bartha, 2, David W. Holdsworth, 2 1Robarts Research Institute, London, Canada; 2The University of Western Ontario, London, Canada

The main purpose of this study was to use high-field MRI, combined with micro-computed tomography, to assess the various bone and cartilage abnormalities associated with a rodent model of Osteoarthritis. The use of pre-clinical models allows for the testing of future pharmacological interventions to treat Osteoarthritis. The benefit of using this technology allows us to scan live rats repeatedly, over 4 week intervals, in less than an hour per session. From these images, we have quantified the loss of cartilage within the knee joint, as well as the appearance of subchondral bone cysts, after the rat undergoes surgical destabilization.

Spine Hall D Monday 14:00-16:00

14:00 3635. Comparison of Lumbar Artery Anatomy and Degenerative Disc Disease in Healthy Controls and Patients with Low Back Pain Combination of Dynamic, Contrast Enhanced Perfusion and MR-Angiogram in the Lumbar Spine Using a 3Tesla MRI Shadfar Bahri1, L. Tugan Muftuler1, Hon J. Yu1, Min- Ying Su1, Jamshid Tehranzadeh1, Anton Hasso1, Orhan Nalcioglu1, Vance Gardner2 1University of California, Irvine, USA; 2Orthopaedic Education and Research Institute of Southern California, Orange, USA

This study investigates the feasibility of a lumbar MRA and vertebral body-perfusion in a single examination. Since the lumbar arterial anatomy has not fully been investigated in vivo so far, the role of the segmental arteries in perfusion of the vertebral body and ultimately delivery of nutrients to the avascular disc is of interest. 31 Healthy controls and patients with back pain have been scanned and the segmental arteries and discs were graded. The control group (8) all showed healthy discs and normal arterial anatomy. The patient group (23) showed 22/23 (94.7%) unhealthy discs and 13/23 (56.5%) stenotic or occluded segmental arteries.

14:30 3636. Apparent Diffusion Coefficient and Fractional Anisotropy in the Vertebral Bone Marrow Yu Ueda1, Tosiaki Miyati1, Naoki Ohno1, Yuko Motono1, Asuka Kouhara1, Masaki Hara2, Yuta Shibamoto2, Harumasa Kasai2, Miyuki Asahi2 1Kanazawa University, Kanazawa, Japan; 2Nagoya City University Hospital, Nagoya, Japan

To assess the state of cancellous tissue, we analyzed ADC and fractional anisotropy (FA) in the vertebral bone marrow using single shot diffusion echo planar imaging. A strong negative correlation was found between ADC and DXA-BMD below moderate marrow fat fraction. Significant correlation was noted between ADC and fat fraction. There was a positive correlation between FA and DXA-BMD, and no correlation between FA and FF in the vertebral bone marrow. In conclusion, diffusion analyses with ADC and FA make it possible to obtain more detailed information of the structure of cancellous tissue and the bone metabolism.

15:00 3637. Mapping Bone Marrow Composition in the Lumbar Spine at 3.0 Tesla Gary Paul Liney1, Clare P. Bernard1, Chris M. Langton, David J. Manton1, Lindsay W. Turnbull1 1University of Hull, Hull, UK

1) To compare data from two quantitative fat imaging methodologies acquired in the lumbar spine. 2) To map the inter-vertebral and age related variations in fat fraction at high spatial resolution. 3) To assess the relationship between volumetric density and marrow content.

15:30 3638. MR Spectroscopy in Intervertebral Disc -- A Feasibility Study Jin Zuo1, Azucena Rodriguez1, Xiaojuan Li1, Thomas Link1, Jeffrey C. Lotz1, Sharmila Majumdar1 1Univ. of California, San Francisco, San Francisco, California , USA

Intervertebral disc degeneration usually begins with biochemical changes within the disc. Quantifying the concentration of the metabolites in the discs would provide objective and important information that is associated with disc degeneration. In this study, the non-invasive single voxel MR spectroscopy was used to assess the concentration of metabolites in intervertebral disc on cadaveric discs. The peak height ratios of the metabolite was correlated with the Pfirrmann grading scheme. In addition, a preliminary in vivo human study was conducted.

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Ultra-Short TE MRI in Musculoskeletal Imaging Hall D Tuesday 13:30-15:30

13:30 3639. Ultrashort TE (UTE) Imaging with Off-Resonance Saturation: Creating High Contrast for Short T2 Tissues Jiang Du1, Atsushi Takahashi2, Christine B. Chung1, Graeme M. Bydder1 1University of California, San Diego, San Diego, California , USA; 2GE Healthcare Technologies, Menlo Park, California , USA

The human body contains a variety of short T2 tissues, including cortical and trabecular bone, tendon, ligaments, etc. Magnetization from these tissues can not be spatially encoded between excitation and acquisition before the signal has completely decayed. These short T2 tissues have a much broader absorption lineshape than the long T2 tissues, making them more sensitive to an appropriately placed off-resonance irradiation. Here we present a technique which combines ultrashort TE (UTE) acquisition with magnetization transfer effect to directly image short T2 tissues with high signal and contrast on a clinical 3T scanner.

14:00 3640. Quantitative Characterization of the Connective Tissues of the Fingers in Cadaveric Specimens: T1 and T2* Measurements Using Ultrashort Echo Time (UTE) MR Imaging in 3T Berna Dirim1, 2, Jiang Du1, Sheronda Statum1, Richard Znamirowski1, Byung Pak1, Graeme Bydder1, Christine B. Chung1 1University of California San Diego, San Diego, California , USA; 2Izmir Ataturk Egitim ve Arastirma Hastanesi , Izmir, Turkey

Little or zero signal is detected from the short T2 tissues with routinely used pulse sequences. UTE pulse sequences can detect signals from these tissues; allow them to be imaged and quantified. We present UTE imaging (minimal TE = 8 µs)and quantitative T1 and T2* characterization of the connective tissues. Six frozen hand specimens were used. Dual echo UTE pulse sequence, for T1 measurement a UTE saturation recovery technique and T2* measurement UTE acquisition with variable TE delays were applied. UTE sequences provide high signal imaging of them and T1, T2* measurements to evaluate them using a clinical scanner.

14:30 3641. Ultrashort TE (UTE) Imaging of the Extensor Tendon Functional Entheses of the Finger Richard Znamirowski1, Mark Bydder1, Christine B. Chung1, Jiang Du1, Atsushi Takahashi2, Won Bae1, Sheronda Statum1, Graeme M. Bydder1 1University of California, San Diego, San Diego, California , USA; 2GE Healthcare Technologies, Menlo Park, California , USA

Entheses are regions where tendons, ligaments or joint capsules are connected to bone. Conventional clinical magnetic resonance (MR) imaging has not been helpful in demonstrating the key tissues present in normal entheses. All these tissues have short transverse relaxation times (T2s), and show little or no signal with typical clinical pulse sequences which have echo times (TEs) of about 8-20 msec or longer. As a result the component tissues of entheses have not previously been identifiable with imaging. Here we report ultrashort TE (UTE) imaging of finger enthesis with high spatial resolution and contrast using a purpose designed finger coil.

15:00 3642. A Comparison of UTE Versus SPRITE for Robust MR Imaging of Short T2 Components Alexandre A. Khrapitchev1, Nicola R. Sibson1, Matthew D. Robson1, Andrew M. Blamire, 12 1University of Oxford, Oxford, UK; 2University of Newcastle, Newcastle, UK

This is a practical comparison between SPRITE and UTE on a 7T animal system. SPRITE is more suitable for imaging of extremely short T2 species, but requires some extra care to avoid damaging gradient systems. UTE can provide shorter examination times but is more challenging to implement and is sensitive to gradient imperfections.

Small Animal Musculoskeletal Imaging Hall D Tuesday 13:30-15:30

13:30 3643. Simultaneous Non-Invasive Determination of Tissue Perfusion, Arterial Blood Pressure and Peripheral Vascular Resistances in Mice Jacques Ménard1, Eric Giacomini1, Céline Baligand1, Didier Bertoldi1, Pierre Carlier2 1Institute of Myology , Paris, France; 2Institute of Myology, Paris, France

We developed a new multiparametric 1H-NMR approach to explore non-invasively the muscular microcirculation in mice. Using a custom-developed setup, we have automated a procedure that allows dynamic determination of skeletal muscle perfusion, systemic blood pressure and vascular resistances in mice. Within a single NMR examination, this non-invasive NMR method can be used to explore the microcirculation control in mouse models. As an application, we showed in vivo that peripheral vascular resistances were increased in the skeletal muscle of db/db mice suffering from type-2 diabetes mellitus.

14:00 3644. Simultaneous High-Resolution Imaging of Mouse Knee and Ankle at 3.0T Using a Specially Designed Dual Array Coil Zhigang You1, Wingchi Edmund Kwok1, Steve Proulx1, Edward Schwarz1 1University of Rochester, Rochester, New York, USA

We have been conducting longitudinal mice knee studies to evaluate arthritides. To enable evaluation of extra-articular manifestations of arthritides and development of multi-organ models, we developed a dual RF coil for simultaneous imaging of mouse knee and ankle at 3T. Since this coil covers only the joint regions needed to be imaged, the total effective coil volume is minimized resulting in high SNR to support high-resolution imaging with 100-micron level resolution. Preliminary data on transgenic mice show this coil can provide information potentially useful for the development of multi-organ models. It should be useful for longitudinal mouse studies of arthritides.

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14:30 3645. MR Texture Analysis of Regenerating Mouse Muscle at 7T: An In-Vivo Study Sandra Même1, Catherine Sébrié2, Jean-Claude Beloeil1, Brigitte Gillet2 1CNRS CBM UPR4301, Orléans, France; 2ICSN CNRS UPR2301, Gif-sur-Yvette, France

The mdx mouse is a model of human muscular dystrophy characterized by a genetic deficiency for dystrophin which leads to numerous spontaneous muscle fibers degeneration-regeneration cycles which are difficult to interpret. A mouse model of muscle injury (with injection of notexin) involving a single well-defined cycle of degeneration-regeneration was studied to distinguish between these two processes, using both MRI texture analysis and histological data. More precisely the aim of this study was to a) monitor the muscle degeneration-regeneration process and b) to define more precisely the local variations of the muscle texture after notexin injection .

15:00 3646. In Vivo MRI of Rabbit Intervertebral Disc Degeneration at 9.4 T: MR Parameters Quantification Allows Identification of Degenerative Discs Fanny Noury1, Sandra Même1, Jean-Claude Beloeil1, Bich-Thuy Doan1, 2 1CBM - CNRS UPR4301, Orleans, France; 2ICSN - CNRS UPR2301, GIF-SUR-YVETTE, France

Intervertebral disc (IVD) degeneration is a complex process characterized by biochemical and structural changes. To study these mechanisms, we follow up the in vivo IVD degeneration by MRI on a rabbit animal model of human lumbar diseases at 9.4 T. To our knowledge, this is the first in vivo study of rabbit IVD degeneration at high magnetic field.We were able to establish a disc degeneration phase classification to characterize the disc degeneration processes chronology.This work is a part of a larger project, aiming to estimate the efficiency of new disc restitution methods in rabbit.

Cartilage Hall D Wednesday 13:30-15:30

13:30 3647. Enhancement of MT, CEST and NOE Contrast Via Intermolecular Multiple Quantum Coherences Wen Ling1, Uzi Eliav1, Xu Yang2, Gil Navon1, Alexej Jerschow2 1Tel Aviv University, Israel; 2New York University, New York, New York, USA

We demonstrate that using intermolecular multiple-quantum coherences can enhance contrast in MTC/CEST/NOE experiments in proportion to (Mz/Mo)p, where Mz is the the saturated level of the z-component of the magnetization, Mo its value in equilibrium and l is the coherence order used. These methods are demonstrated on a series of glycosaminoglycan (GAG) samples, and also for a piece of bovine articular cartilage.

14:00 3648. In-Vivo T2 Mapping and DGEMRIC of Human Hip Cartilage at 1.5T Matthew F. Koff1, David W. Stanley2, Michele R. D'Apuzzo1, Robert T. Trousdale1, Kimberly K. Amrami1, Kenton R. Kaufman1 1Mayo Clinic, Rochester, Minnesota, USA; 2GE Healthcare, Proctor, Minnesota, USA

This study evaluated in-vivo T1 and T2 values of hip cartilage. Coronal T2-weighted images centered on the femoral head were acquired. After administration of Gd-DPTA2- followed by walking and rest, coronal T1-weighted images were acquired. Bulk and depth dependent T1 and T2 values of acetabular and femoral cartilages were calculated. No differences between the bulk T1 or T2 values were found. Femoral cartilage T1 values increased significantly from the superficial zone to the deep zone. The current T1 and T2 values are similar to subjects with known pathologies. The combined scanning method enables a comprehensive quantitative analysis of hip cartilage.

14:30 3649. SPGR and GRE Cartilage Imaging of the Knee at 3T with Water Excitation and 2D Autocalibrating Parallel Imaging Richard Kijowski1, Reed Busse2, Scott Reeder1, Kuya Takami1, Philip Beatty3, Anja Brau3, Anthony Vu4 1University of Wisconsin, Madison, USA; 2General Electric Healthcare, Madison, USA; 3General Electric Healthcare, Menlo Park, USA; 4General Electric Healthcare, Waukesha, USA

The purpose of this study was to document the feasibility of performing dark fluid SPGR and bright fluid GRE cartilage imaging at 3T using water excitation (SSI) and an autocalibrating 2D-accelerated parallel imaging technique called ARC. SSI-SPGR and SSI-GRE sequences with and without ARC parallel imaging were performed twice on the knees of 8 asymptomatic volunteers. SNR efficiency and CNR efficiency measurements were performed using a double acquisition addition/subtraction method. ARC accelerated SPGR and GRE cartilage imaging without causing a reduction in SNR and CNR efficiency.

15:00 3650. High-Resolution Morphological and Biochemical Imaging of Articular Cartilage of the Ankle Joint at 3.0 T Using a New Dedicated Phased Array Coil: In-Vivo Reproducibility Study Goetz Hannes Welsch1, Tallal Charles Mamisch2, Michael Weber1, Stefan Nemec1, Klaus Bohndorf3, Siegfried Trattnig1 1Medical University of Vienna, Vienna, Austria; 2University of Berne, Berne, Switzerland; 3Klinikum Augsburg, Augsburg, Germany

MRI of thin cartilage layers puts challenging demands on imaging techniques. High resolution with sufficiently SNR has to be achieved without prolonging acquisition time too much. High-field-MRI, advanced coil technology, sophisticated sequences and imaging techniques provide the basis of the imaging protocol used in this study.The object was to determine the precision of high-resolution isotropic 3D-TrueFISP imaging of ankle cartilage and to show the feasibility of quantitative T2-imaging.To best of our knowledge this is the first study to evaluate in-vivo high-resolution morphological isotropic(0.31x0.31x0.31mm3) TrueFISP-imaging and biochemical T2-mapping within the ankle joint in a clinically acceptable scan-time of each about 10 minutes.

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13:30 3651. Quantitative and Qualitative Assessment of Multiple New 3T Cartilage Imaging MR Pulse Sequences Richard Kijowski1, Jessica Klaers1, Kuya Takami1, Kirkland Davis1, Michael Tuite1, Kazuhiko Shinki1, Anthony Vu2, Scott Reeder1, Walter Block1, Reed Busse3 1University of Wisconsin, Madison, USA; 2General Electric Healthcare, Waukesha, USA; 3General Electric Healthcare, Madison, USA

This study was performed to compare multiple promising new MR pulse sequences for evaluating the articular cartilage of the knee joint at 3T. FSE-Cube, MENSA, IDEAL-GRASS, IDEAL-SPGR, COSMIC, and VIPR-SSFP sequences were performed on the knees of 10 asymptomatic volunteers and 5 patients with osteoarthritis. SNR and CNR measurements were obtained. A qualitative assessment of image quality was performed by 3 musculoskeletal radiologists. All sequences had certain strengths and weaknesses with no clear cut “winner” in the quantitative and qualitative comparison. The relative advantages and disadvantages of each sequence may make them best suited for different cartilage imaging applications.

14:00 3652. Correlation of DTI Derived Metrics with Synovial Fluid Inflammatory Cytokines from Patients of Arthritis with Inflammation of the Knee Joint Manoj Kumar1, Vikas Agarwal1, Ram KS Rathore2, Amit Prasad1, Jitesh Kumar Singh2, Ram Nath Mishra1, Kashi N. Prasad1, Rakesh K. Gupta1 1Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India; 2Indian Institute of Technology, Kanpur, India

The inflammation that accompanies the pain and swelling associated with inflammatory arthritis is mediated by complex interactions of inflammatory cytokines. DTI was performed in 7 arthritis patients with inflammation (three osteo and four rheumatoid arthritis). JAVA based software was used for DTI data process as well as cartilage segmentation. Synovial fluid was taken from knee joints of these patients and inflammatory cytokines were quantified by ELISA technique. The Pearson’s correlation between DTI derived metrics and inflammatory cytokines was significant. DTI derived metrics and inflammatory cytokines may be used as surrogate markers for the activity of disease in arthritis patients.

14:30 3653. Quantification of Capillary Blood Flow and Endothelial Permeability in Inflammatory Joint Diseases: MR-Perfusion Results Sabine Weckbach1, Steven P. Sourbron1, Mike Notohamiprodjo1, Hans Hatz2, José Raya1, Maximilian F. Reiser1, Christian Glaser1 1University Hospital Munich- Grosshadern, Munich, Germany; 2Klinik Feldafing, Feldafing, Germany

By using a two-compartment model and an MR sequence with high temporal resolution a separate quantification of blood flow and permeability in patients with inflammatory joint diseases seems possible with stable and plausible results. Compared to previous studies a direct measurement of capillary blood flow and a ROI-based mapping of perfusion parameters might improve sensitivity and specificity with regard to future therapy control studies.

15:00 3654. Assessment of T1 and T2 MRI Parameters as a Predictors of Cartilage Implants Maturation: The Equine Subject Study Vladimir Juras1, 2, Pavol Szomolanyi, 23, Zuzana Majdisova, 23, Siegfried Trattnig3 1Medical University of Vienna, Vienna, Austria; 2Slovak Academy of Sciences, Bratislava, Slovakia; 3MR Centre / Highfield MR, Medical University of Vienna, Vienna, Austria

Qualitative and quantitative assessments of MR relaxation parameters T1 and T2 in equine articular cartilage were compared to histology grading. Equine subjects were treated by Matrix-associated Autologous Chondrocyte Implantation (MACI) with three different implant routinely used in clinical applications. The degree of the maturation process could be determined by zonal T2 organization and by absolute quantification of relative R1 of native and repaired cartilage. T2 reflects the matrix organization, whilst R1 is related to proteoglycans content. The results proved that MRI can be prospectively used as a non-invasive imaging modality for post operative monitoring following autologous chondrocyte implantation.

13:30 3655. T1ρ Relaxation Evaluation of Knee OA in a Guinea Pig Model Chenyang Wang1, 2, Matt Fenty1, Ari Borthakur1, George Dodge2, Ravinder Reddy1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA; 2Thomas Jefferson University, Philadelphia, Pennsylvania, USA

Osteoarthritis (OA) is a painful and costly medical condition, affecting millions of people every year. In this study, we intend to demonstrate the feasibility of using T1ρ MRI to monitor the progression of OA in a spontaneous animal model. The animal model is based on Dunkin-Hartley guinea pigs, which have been shown to spontaneously develop OA as they age. In addition, T1ρ MRI has been shown to be sensitive to OA changes in human and bovine cartilage. Since T1ρ MRI is non-invasive, this animal model of OA can be used to evaluate the efficacy of potential OA therapies in vivo.

14:00 3656. 7 Tesla MR - Initial Results on T2 and T2* Mapping of Healthy Articular Cartilage and Cartilage Repair Tissue Goetz Hannes Welsch1, Tallal Charles Mamisch2, Sebastian Quirbach1, Timothy Hughes3, Oliver Kraff4, Mark E. Ladd4, Christoph Zilkens5, Oliver Bieri6, Klaus Scheffler6, Siegfried Trattnig1 1Medical University of Vienna, Vienna, Austria; 2University of Berne, Berne, Switzerland; 3Siemens Medical Solutions, Erlangen, Germany; 4University of Essen, Essen, Germany; 5University od Duesseldorf, Duesseldorf, Germany; 6University of Basel, Basel, Switzerland

Ultra-high-field whole body systems (7.0T) have high potential in future human in-vivo MRI. In musculoskeletal MRI mainly biochemical imaging of articular cartilage may benefit. Here T2 mapping has shown its potential, also in the evaluation of zonal variation as an indicator of hyaline or hyaline-like articular cartilage, however implying high spatial resolution. Thus the aim of our study was to show the feasibility of T2 and additionally T2* relaxation measurements at 7T MRI as well as to evaluate its potential in an initial patient study after matrix associated autologous chondrocyte transplantation (MACT) within the knee.

14:30 3657. Reproducibility of Automatic Quantitative Analysis of the Articular Cartilages from MEDIC and WeDESS Magnetic Resonance Images of the Knee at 1.5T Jurgen Fripp1, 2, Valer Jurcak2, Ross Holt3, Sebastien Ourselin1, Craig Engstrem2, Stuart Crozier2 1BiomedIA Lab, e-Health Research Center, Brisbane, Australia; 2University of Queensland, Brisbane, Australia; 3Southernex Imaging, Australia

We present a cartilage segmentation approach for MRIs of the knee and test the reproducibility and test-retest error found when acquiring weDESS and MEDIC images from healthy volunteers at 1.5T.

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15:00 3658. dGEMRIC at 7 Tesla - Feasibility Study Siegfried Trattnig1, Goetz H. Welsch1, Katja Pinker1, Timothy Hughes2, Oliver Kraff3, Mark Ladd3, Pavol Szomolanyi1, 4, Oliver Bieri5, Klaus Scheffler5, Tallal C. Mamisch6 1MR Centre - Highfield MR, Vienna, Austria; 2Siemens AG, Erlangen, Germany; 3University Hospital, Essen, Germany; 4Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia; 5University of Basel - MR Physics, Basel, Switzerland; 6Inselspital, Bern, Switzerland

For the quantification of glycosaminoglycan content in articular cartilage delayed Gadolinium Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) is the method of choice.Ultrahigh field (7T) systems are increasingly used for clinical studies in patients, which provide higher resolution and which may improve diagnostic accuracy. In this study the feasibility of dGEMRIC technique at 7T was shown in phantoms and in volunteers with a range between pre-and postcontrast T1 values at 7T similar to 3T. However, to get reliable results inversion recovery technique for T1 mapping has to be performed and the calculation of the delta relaxation rate is mandatory.

13:30 3659. Novel Usages of Distance Function in Fully Automatic Articular Cartilage Segmentation Feng Huang1, Xiaoming Chen2, Deliang Ye1, Sarah Hertel3 1Invivo Corporation, Gainesville, Florida, USA; 2University of Florida, Gainesville, Florida, USA; 3Invivo Corporation, Pewaukee, Wisconsin, USA

In this study, we propose to use distance function to attack several difficulties in cartilage segmentation. Distance function of an object is defined as the smallest distance from a point in the domain to the object. Given segmented bones, distance function of these bones can be calculated. In this work, distance function is proposed to: 1) reduce the search region of cartilages; 2) segment cartilages based on the smoothness of cartilage thickness when there is no contrast between cartilages and surrounding soft tissues; 3) separate contacted cartilages when there is no obvious contrast between them; 4) provide thickness map for cartilages. The proposed method was tested on twelve MRI data sets.

14:00 3660. Development of T-Scores for the Diagnosis of Osteoarthrosis of the Patellofemoral Joint Using Quantitative MR Volumetry of Cartilage Sabine Weckbach1, Annie Horng1, Gudrun Pforte1, Raya José1, Felix Eckstein2, Martin Hudelmeier3, Maximilian F. Reiser1, Christian Glaser1 1University Hospital Munich- Grosshadern, Munich, Germany; 2Paracelcus Medical University, Salzburg, Austria; 3Insitute of Anatomy, Salzburg, Austria

The purpose of this study was to evaluate T-scores based on quantitative cartilage volumetric parameters for the diagnosis of patellofemoral osteoarthritis. Sensitivities and specificities obtained for selected cutoff values suggest that T-scores based on quantitative cartilage volumetric parameters may be a suitable adjunct for the diagnostic workup of OA in population based studies / approaches.

14:30 3661. Kinematic Biochemical Studies of Cartilage Transplants at 3Tesla Siegfried Trattnig1, Tallal Ch. Mamisch2, Christina Plank1, Pavol Szomolanyi1, 3, Sebastian Quirbach1, Goetz H. Welsch1 1MR Centre - Highfield MR, Vienna, Austria; 2Inselspital, Bern, Switzerland; 3Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia

A flexible knee coil which allows to assess quantitative cartilage MR data in different positions from 40 flexion to full extension was applied to examine in T2 and diffusivity values in the femoral cartilage of volunteers and patients after autologous chondrocyte transplantation (ACI). Changes of T2 and diffusivity in cartilage could be demonstrated by position dependent contact of two cartilage layers alone. Since repair tissue shows a different behaviour in the contact zone compared to healthy cartilage a possible marker for an improved evaluation of the repair tissue quality after ACI may be available providing biomechanical information on cartilage transplant.

15:00 3662. 3D GRE Sequence with Two Different Flip Angle Excitation Pulses for Zonal T1- Mapping of Articular Cartilage at 3T: One-Year Follow-Up in Patients After Matrix-Associated Autologous Chondrocyte Transplantation (MACT) of the Knee Joint Katja Pinker1, Pavol Szomolanyi2, Goetz Welsch1, Tallal Charles Mamisch3, Stefan Marlovits4, Siegfried Trattnig1 1MR Centre of Excelllence, Vienna, Austria; 2Slovak Academy of Sciences, Bratislava, Slovakia; 3Inselspital, Bern, Switzerland; 4Medical University Vienna, Vienna, Austria

To evaluate the global and zonal distribution of glycosaminoglycans (GAG) in normal weight-bearing cartilage and repair tissue by dGEMRIC method using a 3D GRE sequence with a 35/10 flip angle excitation pulse combination and to monitor the development of zonal and global GAG content in MACT over one year.

Musculoskeletal Miscellaneous Hall D Thursday 13:30-15:30

13:30 3663. Magnetization Transfer Effects in Human Median Nerve at 3 T Giulio Gambarota1, Ralf Mekle1, Rolf Gruetter1, 2 1Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland; 2University of Lausanne and University of Geneva , Switzerland

The values of magnetization transfer (MT) ratio are well established for most clinical relevant tissues. However, despite the potential of MT contrast to assess demyelination, which is one of the common features of a number of peripheral nervous system (PNS) pathologies, no measurements of MTR have been performed to date on human PNS. The purpose of this study was to determine the MTR in human median nerve to provide baseline values of MTR for the PNS in healthy volunteers.

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14:00 3664. High-Resolution MR Imaging of the Foot: Magnetization Transfer Effects in Foot Peripheral Nerves Giulio Gambarota1, Ralf Mekle, Rolf Gruetter1, 2 1Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland; 2University of Lausanne and University of Geneva, Switzerland

MT contrast in foot nerves could be of interest for early detection of diabetes-induced peripheral neuropathy. In this work, we sought to image foot nerves and to measure the MT ratio (MTR), at 3 T. A substantial reduction of MTR was observed in the nerves (MTR in 25-35% range), compared to muscle (42-50% range). The results of this study indicate that the high signal-to-noise ratio afforded at the field strength of 3 T and the use of high-sensitivity coils allows not only for the visualization of foot nerves but also for quantitative assessment of their intrinsic MR properties.

14:30 3665. Consistent Automated Scan Planning of Shoulder Chiel JM den Harder1, Johan W. de Jong1, Clemens Bos1, Marius van Meel1, Daniel Bystrov2, Harald Heese2, Arjan W. Simonetti1 1Philips Medical Systems, Best, Netherlands; 2Philips Research Laboratories, Hamburg, Germany

Consistent planning of MRI scans of patients who undergo a shoulder examination is very important. It enables radiologists to investigate the patients’ anatomy with a preferred ‘orientation’. However, planning between operators may be biased due to their training, competence and experience. To deal with this problem, an automated scan planning for shoulder examinations was developed and a feasibility study was performed. The study showed that the proposition of the system was in line with manual planning of an experienced operator. The automated scan planning procedure can be integrated into the examination protocol, thus improving workflow and achieving a one push button examination.

15:00 3666. MRI of an Egyptian Mummy on Clinical 1.5 and 3 T Whole Body Imagers Michael Bock1, Peter Speier2, Sonia Nielles-Vallespin2, Michael Szimtenings2, Karin Leotta1, Frank Rühli3 1Deutsches Krebsforschungszentrum (dkfz), Heidelberg, Germany; 2Siemens Medical Solutions, Erlangen, Germany; 3University of Zurich, Zürich, Switzerland

Non-destructive proton MRI of the head of an Egyptian mummy was performed on 1.5 T and 3 T clinical MRI systems. Three different pulse sequences were used that offered echo times below 1 ms to overcome the low SNR due to the short T2* of the mummified tissue. Of these, a 3D radial pulse sequence offered the highest SNR per unit time, and 3D data sets of excellent quality could be acquired in less than 1 hour.

13:30 3667. Responsiveness of BOLD MRI to Short-Term Temperature Changes of the Rabbit Knee Joint in Inflammatory Arthritis Cristina Otilia Nasui1, George Nathanael, Elka Miller, Jaques Belik, Adrian Crawley, Andrea S. Doria 1Hospital for Sick Children, Toronto, Canada

BOLD MRI is a suitable tool to assess local tissue oxygen levels as dependent on local temperature with most significant responsiveness changes noted in the knee contralateral to the knee where arthritis was induced. Physiologic compensatory mechanisms in the contralateral joint may explain these results. Further assessment of responsiveness of BOLD MRI in arthritic joints with higher magnetic field scanners may confirm the current results and enhance potential changes.

14:00 3668. Isotropic MRI of the Ankle at 3.0T Using 3D-FSE-Cube with Extended Echo Train Acquisition (XETA) Garry E. Gold1, Reed F. Busse2, Kathryn J. Stevens1, Eric Han3, Anja C.S. Brau3, Philip J. Beatty3, Christopher F. Beaulieu1 1Stanford University, Stanford, California , USA; 2GE Healthcare, Madison, Wisconsin, USA; 3GE Healthcare, Menlo Park, California , USA

Two-dimensional fast spin-echo (2D-FSE) is frequently used to evaluate the ankle joint. This approach is limited, however, by partial volume artifacts and slice gaps. Volumetric acquisition with isotropic resolution overcomes these limitations and allows reformations in multiple planes. We compared 2D-FSE in the ankle at 3.0T with 3D-FSE-Cube, a new technique with a variable refocusing flip angle eXtended Echo Train Acquisition (XETA) and 2D-accelerated autocalibrated parallel imaging (ARC) to achieve isotropic resolution in clinical feasible scan times. 3D-FSE-Cube showed high signal-to-noise and had the ability to reformat in any plane, making multiple 2D acquisitions unecessary. 3D-FSE-Cube is a promising method for clinical ankle imaging.

14:30 3669. Spectroscopic Imaging Using Interleaved Projection Sampling Along the 3D Cartesion Phase and Slice Encodings (SIPPS): Application to Articular Cartilage Jiang Du1, Christine B. Chung1, Graeme M. Bydder1 1University of California, San Diego, San Diego, California , USA

Fat water separation is of important clinical applications. Conventional fat saturation pulse is efficient but may provide non-uniform fat suppression and reduced water signal in regions of field inhomogeneity. Two-point or multi-point Dixon techniques are extensively investigated for robust fat water separation. Here we present a time efficient and robust fat water separation technique based on spectroscopic imaging using interleaved projection sampling along the 3D Cartesian phase and slice encodings (SIPPS), which provides high resolution 3D water and fat images at a series of resonance frequencies.

15:00 3670. Orientational Effect on Achilles Tendon Investigated with Ultrashort TE Spectroscopic Imaging (UTESI) Sequence Jiang Du1, Byung C. Pak1, Atsushi Takahashi2, Richard Znamirowski1, Sheronda Statum1, Graeme M. Bydder1, Christine B. Chung1 1University of California, San Diego, San Diego, California , USA; 2GE Healthcare Technologies, Menlo Park, California , USA

Fat water separation is of important clinical applications. Conventional fat saturation pulse is efficient but may provide non-uniform fat suppression and reduced water signal in regions of field inhomogeneity. Two-point or multi-point Dixon techniques are extensively investigated for robust fat water separation. Here we present a time efficient and robust fat water separation technique based on spectroscopic imaging using interleaved projection sampling along the 3D Cartesian phase and slice encodings (SIPPS), which provides high resolution 3D water and fat images at a series of resonance frequencies.

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Muscle Hall D Thursday 13:30-15:30

13:30 3671. Mapping of Movements in the Dynamically Contacting Human Triceps Surae Muscles Using a Computer Controlled Hydraulic Foot-Pedal Device with Velocity Encoded Phase Contrast MRI Dongsuk Shin1, Ryuta Kinugasa2, Chandan Mishra2, John Hodgson1, V. Reggie Edgerton1, Shantanu Sinha2 1University of California, Los Angeles, California , USA; 2University of California, San Diego, California , USA

The new hydraulic foot-pedal device was developed to create the dynamic and active muscle contractions inside the MRI bore. In comparison to the isometric contraction mode, the velocity/displacement behavior was changed, providing new insights in muscle-tendon mechanics previously undetectable under the isometric contraction mode.

14:00 3672. Three-Dimensional Muscle Models of the Human Triceps Surae Muscle-Tendon Complex Dongsuk Shin1, Sheng-Wei Chi1, Jiun-Shyan Chen1, John Hodgson1, V. Reggie Edgerton1, Shantanu Sinha2 1University of California, Los Angeles, California , USA; 2University of California, San Diego, California , USA

We propose a newly developed three-dimensional FE model that incorporates the aponeurosis-tendon unit as well as soleus muscle. The outcome of the model demonstrates the inhomogeneous strain distribution along the aponeurosis-tendon complex under different MVC levels, which is in good agreement with our previously reported PC-MRI data. The model suggests geometrical changes in the muscle-tendon system, recruitment of active/passive components, and ankle rotation all may contribute to non-uniform strain distribution.

14:30 3673. Muscle Functional Magnetic Resonance Imaging Using Ultrafast Imaging Noriyuki Tawara1, Osamu Nitta2, Hironobu Kuruma2, Mamoru Niitsu2, Akiyoshi Itoh3 1Japan Institute of Sports Sciences, Kita-ku, Japan; 2Tokyo Metropolitan University, Arakawa-ku, Japan; 3NIHON University, Funabashi-sity, Japan

Exercise selectively increases the signal intensities (SI) of active muscles in T2-weighted magnetic resonance (MR) images. Investigators in sports medicine and other related fields have utilized T2 maps to investigate skeletal muscle activity during exercise. However, scan time of T2-weighted MR images is usually for a few minutes. So, we can choose only the location that is secured for long time. In this paper, we report the speed-up of fusion image of magnetic resonance imaging for visualization of muscle activity. Spin-echo echo-planar-imaging (SE-EPI) that is ultrafast imaging has weak-point that is low spatial resolution. In order to compensate for weak-point, we used TrueFISP that is ultrafast imaging of high spatial resolution. And we proposed the new method using fusion SE-EPI and TrueFISP. We compared skeletal musclefs T2 relaxation curve between SE-PEI and multiple spin echo (MSE) that is conventional method, SE-EPI is similar to MSE in short TE. In short TE than 75 ms, SE-EPI indicated the possibility of use in pulse sequence of T2-weighted MR images. Also, a 1/13 was able to shorten it than MSE sequence in MRIfs scanning time.

15:00 3674. Quantitative Assessment of Muscle Degeneration in DM1 Patients Using MRI bassem Hiba1, Nathalie Richard1, Luc J. Hébert2, Christophe Vial3, Mimoun Nejjari1, Jean francois Remec3, Chantale coté2, Francoise Bouhour3, Jack Puymirat*2, Marc Janier1, 4 1Université Lyon1, Lyon, France; 2Laval CHU, Québec, Canada; 3Wertheimer Hospital, Lyon, France; 4Hospices Civils de Lyon, Lyon, France

MRI is a very promising technique for muscle degeneration exploration, even though only some descriptive or qualitative results were reported in the literature. We propose a quantitative exploration of muscle degeneration in Steiner’s myotonic dystrophy using MRI (particularly in Tibialis Anterior muscles). 17 DM1 patients and 6 controls were included in the study, normal and degenerated tissue volumes, oedema volume and the fat to water ratio were assed from MR images. The proposed measurements were validated comparing with relative isometric strength measured by a hand-held dynamometer.

13:30 3675. Evaluation of Muscle Fiver Tractography by Single-Shot Diffusion Tensor STE EPI Jyunichi Hata1, Kazuo Yagi1, Keigo Hikishima1, Ryou Takaki1, Yuuji Komaki1 1Tokyo Metropolitan University, Arakawa, Japan

The STE method can achieve high SNR in the diffusion weighted image of the skeletal muscle. We mounted DT STE-EPI on 1.5T MRI scanner and evaluated Toractography of the human skeletal muscle. Result, It is necessary to impress about at least b-value 800-1000 [s/mm2] to the muscle fiber tracking as well as central nerve area. The muscle fiber toractography showed the anatomical structure similar to fiber structure measured by other modalities. Muscle fiber Toractography will do a contribution to the muscle disease diagnosis, the muscle function evaluation, and the sport medicine in the future.

14:00 3676. Continuous Arterial Spin Labeling in Progressive Peripheral Vascular Disease Wen-Chau Wu1, Jiongjiong Wang1, Ping Wang1, John A. Detre, Temitope Olufade, Thomas F. Floyd1 1University of Pennsylvania, Philadelphia, USA

Measurement of muscle perfusion in the extremities is feasible using arterial spin labeling (ASL) MRI. In this study, we utilize continuous ASL (CASL) to measure the perfusion in patients with peripheral vascular disease. Flow variability is analyzed for individual muscle groups and correlated to the disease severity assessed by the ankle to brachial index (ABI). Results show that CASL flow measurements correlate with disease state as measured by ABI, but also demonstrate a retained microvascular flow reserve in the presence of early to intermediate vascular disease. Progression of disease is followed by diminished flow reserve and delayed hyperemic response.

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14:30 3677. Magnetisation Transfer Ratio in Leg Muscle, and Sciatic Nerve Size in Hereditary Demyelinating and Chronic Inflammatory Demyelinating Polyneuropathy Peter Oliver Cowley1, Mario Miranda1, John Thornton2, Lisa Strycharczuk11, Hiten Mehta1, Mary Reilly1, Martin Koltzenburg1, Tarek Yousry1 1National Hospital for Neurology and Neurosurgery, London, UK; 2National Hospital for neurology and neurosurgery, London, UK

Sciatic nerve cross-sectional area in the thigh and calf-muscle magnetisation transfer ratios (MTRs) were determined in patient groups with inherited (CMT1a) and acquired (CIDP) peripheral neuropathies and a control group (n=10 in each group). Sciatic nerve areas were significantly enlarged in both disease groups, to a greater degree in CMT1a (p<0.001). MTRs were reduced in affected muscle groups, the reduction correlating with age (and presumed disease duration) in the CMT group.

15:00 3678. Relaxation Times of Human Skeletal Muscle Metabolites at 7T Ligong Wang1, Nouha Salibi2, Mark E. Schweitzer1, Ravinder R. Regatte1 1Center for Biomedical Imaging, NYU School of Medicine, New York, USA; 2Siemens Medical Solutions, Malvern, Pennsylvania, USA

This study reports ultra high field (7T) proton relaxation times of lipid metabolites in human tibialis anterior muscles. T1 and T2 relaxation times of lipid phantom (corn oil) and healthy human volunteers (n=3) were measured using single voxel 1H MR spectroscopy of skeletal muscle. The T1 values of TMA, Cr-CH3, IMCL-CH2, and EMCL-CH2 for TA muscle at 7T are 1310, 1516, 1605, and 1479 ms, while the T2 values of the corresponding metabolites are 62.4, 56.81, 57.9, and 58.5 ms. The relaxation numbers can be utilized for the absolute quantification of skeletal muscle metabolite concentrations and optimization of sequence parameters.

Renal Parenchyma & Perfusion Hall D Monday 14:00-16:00

14:00 3679. Renal Cortical and Medullar Oxygenation Changes After Oxygen Challenge: Evaluation with BOLD MRI Hersh Chandarana1, Mohit Naik1, Pippa Storey1, Vivian Lee1, Bachir Taouli1 1NYU Medical Center, New York, New York, USA

In this study we evaluated the effect of inhaled oxygen on changes in renal cortical and medullary T2* signal with BOLD imaging in patients with normal renal function. Our study demonstrates significant increase in oxygenation of the medulla (mean 12.2%) and to a lesser extent in the cortex (2.4%), confirming that in normal kidneys, the medulla is more hypoxic than the cortex and demonstrates significant change in oxygenation after oxygen challenge.

14:30 3680. Clinical Value of MR-Based Quantification of Renal Perfusion Parameters with a Separable Two-Compartment Model Ulrike Attenberger1, Henrik Michaely2, Steven Sourbron3, Mike Notohamiprodjio3, Christian Glaser3, Maximilian Reiser3, Stefan Schoenberg2 1Ludwig-Maximilians University Munich, Munich, Germany; 2University of Heidelberg, Germany; 3Ludwig-Maximilians University Munich, Germany

The combination of MR angiography and MR perfusion (MRP) measurements offers a promising method for detection of macrovascular and microvascular renal disease in a single exam. So far, there is no ideal technique for direct measurement of renal function. We used a separable two-compartment model for quantification of renal perfusion paramters in this study and investigated the diagnostic accuracy of a combined MRA/MRP approach compared to the final clinical diagnosis. 25 patients underwent renal perfusion measurements and renal MR angiograpyh at a 3.0T scanner (Siemens Magnetom Tim Trio). The sequence parameters of the SR-TurboFLASH sequence were: TR / TE/ TI [ms] 203/0.90/101, flip angle 12º, bandwith [Hz/Px] 900, matrix 192x134, FOV[mm3] 450x373, temporal resolution [slice/s] 5, parallel imaging GRAPPA 2. The sequence parameters of the 3D MRA sequence were: TR/ TE [ms] 3.11/ 1.09, flip angle 23º, bandwidth [Hz/Px] 510, matrix 512x85%, FOV [mm²] 400x81.3%, phase oversampling [%] 8, interpolated slice thickness 0.9 [mm], voxel size [mm3] 0.65, spatial resolution [mm³] 0.9x0.8x0.9, scan time [s] 19. From all patients the final clinical diagnosis was obtained as a reference standard. 15 patients were classified as ill based on the final clinical diagnosis. 3 patients with renal artery stenoses, 5 patients with renal insufficience in compensated retention, 7 patients after renal transplantation with postoperative complications MRA alone had a sensitivity of 73% and specifity of 90%. MRP reached a sensitivity of 100% and a specifity of 70% respectively. In combination MRA and MRP revealed a sensitivity of 100% and specifity of 90%.We could show that the combination of both methods - MRA and MR perfusion - heightens overal diagnostic accuracy. Especially in patients with renoparenchymal diseases the additional information of perfusion measurements increases the diagnostic specifity.

15:00 3681. Dual Navigator Gated FAIR True-FISP Pulse Sequence for Renal Perfusion Imaging Ruitian Song1, Ralf Berthold Loeffler1, Claudia Maria Hillenbrand1 1St. Jude Children's Research Hospital, Memphis, Tennessee, USA

A dual navigator gated FAIR True FISP pulse sequence has been developed and implemented. Two navigators are applied to gate tagging and imaging slices, respectively. Since both slices are gated and followed to the same reference position, the imaging slice is prevented from moving to the edge of or out of the inversion slice. Error caused by not or not fully tagged spins could be eliminated in measuring renal perfusion rate, and pixel-mismatch between the tagging and control images could also be improved.

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15:30 3682. MR-Based Semi-Automated Quantification of Renal Perfusion Functional Parameters with a Two-Compartment Model - An Interobserver Analysis Ulrike Attenberger1, Steven Sourbron1, Mike Notohamiprodjio1, Christian Glaser1, Maximilian Reiser1, Stefan Schoenberg2, Henrik Michaely2 1Ludwig-Maximilians University Munich, Munich, Germany; 2University of Heidelberg, Mannheim, Germany

Dynamic contrast-enhanced magnetic resonance imaging of the kidneys offers promising approaches for the assessment and differentiation of renovascular and renoparenchymal diseases. For the determination of both renal first-pass perfusion (plasma flow, plasma mean transit time) and renal filtration (tubular flow, tubular mean transit time) parameters we used a separable two-compartment model. The purpose of this study was to evaluate interobserver agreement in the quantitative assessment of renal functional parameters as it is known, that variability of functional parameters is a well-addressed problem. 12 consecutive patients (4 men, 8 women, mean age 51 years) underwent renal perfusion measurements after intravenous injection of 7 ml Gd-BOPTA (Multihance®, Bracco) at 4 ml/s at 3.0T (Magnetom Tim Trio). The sequence parameters of the SR-TurboFLASH sequence were: TR / TE/ TI [ms] 203/0.90/101, flip angle 12º, bandwidth [Hz/Px] 900, matrix 192x134, FOV[mm3] 450x373, temporal resolution [slice/s] 5, parallel imaging GRAPPA 2.Two independent observers placed regions of interest (ROIs) manually on an axial slice, one in the abdominal aorta for determination of arterial input function, one at the air-tissue interface for retrospective respiratory motion correction. Fitting the data on a pixel-by-pixel basis to the two-compartment model maps of the perfusion parameters and tubular filtration parameters were obtained. Pixels with plasma volume > 10 ml/100ml were selected to segmente a cortical ROI. The model fit was repeated on a ROI basis to produce the cortical averages.Correlations of all values were significant (p<0.05). A paired t-test yielded significant differences for plasma flow values (p=0.004).The data shows a systematic difference for the plasma flow parameter, while plasma mean transit time parameter seems to be most stabile.The difference in flow parameters reflects a user-dependent bias in AIF selection, which may be minimized in future work by incorporating (semi)automated segmentation to identify the lumen of the aorta.

14:00 3683. QUIPSS II with Interleaved Thin-Slice TI1 Periodic Saturation for FAIR Sequence Ruitian Song1, Ralf Berthold Loeffler1, Claudia Maria Hillenbrand1 1St. Jude Children's Research Hospital, Memphis, Tennessee, USA

QUIPSS II with interleaved thin-slice TI1 periodic saturation has been developed and integrated into a FAIR TrueFISP ASL experiment for the quantification of renal perfusion. A periodic thin-slice saturation pulses were applied alternatively on both sides of the imaging slice from TI1 to TI1S (TI1 stop time). It has been shown that the bolus width can be controlled by changing TI1 and the better matched saturation slice profiles can be achieved. The renal perfusion rate could be quantified more accurately with our technique

14:30 3684. Evaluation of Dysfunctional Renal Transplants Using Low-Dose MR Renography Louisa Bokacheva1, Henry Rusinek1, Keyma Prince1, Manmeen Kaur1, Thomas Diflo1, Devon John1, Judith Benstein1, Laura Barisoni-Thomas1, Vivian Lee1 1New York University School of Medicine, New York, USA

Dynamic contrast-enhancement MR imaging of the kidneys (MR renography) was used to evaluate patients with normally functioning renal transplants and with transplants during dysfunctional episodes caused by acute tubular necrosis and mild rejection. Contrast concentration versus time curves for renal cortex and medulla were evaluated. The maximum cortical concentration was shown to be significantly lower in ATN cases than in normal or rejected kidneys. The cortical and medullary concentrations at 120 s after the start of acquisition were also significantly lower in kidneys with ATN than in normal or rejected kidneys. The differences between rejected and normal kidneys were insignificant. These findings suggest that MR renography can be used to elucidate the nature of the renal transplant dysfunction.

15:00 3685. Glomerular Filtration Rate Measurements by Dual-Injection MR Renography Jeff Lei Zhang1, Henry Rusinek1, Louisa Bokacheva1, Qun Chen1, Pippa Storey1, Chekema Prince1, Vivian S. Lee1 1New York University, New York, New York, USA

Dual-injection MR renography has been proposed as an improved diagnostic marker of renovascular disease. Technical challenges include optimal split of one dose for two injections and appropriate analysis of the second renography dataset. Monte Carlo simulation showed that with overall dose of 12 ml 6-8 ml should be used for the second injection, and with dose1 of 4 ml, standard deviation of GFR1-GFR2 was less than 5.1 ml/min. For patients without RAS, GFR1 and GFR2 have a high correlation coefficient R2 = 0.81, and for 30 cases (out of 40) the difference (GFR1 – GFR2) was within [-10, 10] ml/min.

15:30 3686. MR Diffusion Tensor Imaging of the Kidney with Parallel Imaging – Initial Clinical Experience Mike Notohamiprodjo1, Christian Glaser1, Karin Anna Herrmann, Ulrike Attenberger, Stefan Schoenberg, Maximilian Reiser, Henrik Michaely 1University Hospitals Munich, Munich, Germany

The purpose of this study was to evaluate the feasibility of MR-Diffusion Tensor Imaging (DTI) of the kidney with integrated parallel imaging in volunteers and patients with various renal diseases.10 volunteers and 27 patients with various renal pathologies underwent MR-DTI. MR-DTI allows a good discrimination between cortex and medulla and visualization of renal architecture alterations, e.g. by tumors or parenchymal disease. Differentiation of simple cysts, cystic and solid renal cell cancer was possible. The results suggest that MR-DTI with integrated parallel imaging may be a useful tool to study and monitor renal ultrastructure.

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Hyperpolarized Gas Lung MRI Hall D Monday 14:00-16:00

14:00 3687. Lung Ventilation Mapping with Bolus Inhalation of He-3 and Dynamic Projection He-3 MRI Using I-HYPR Reconstruction Ryan Cullen Lipscomb1, Rafael Louis O'Halloran1, James H. Holmes1, Sean B. Fain1 1University of Wisconsin, Madison, Wisconsin, USA

Rapid 2D hyperpolarized He-3 MRI with projection and iterative highly constrained back-projection (I-HYPR) reconstruction was applied to dynamic imaging of a compact inhaled bolus in a healthy human volunteer at a temporal resolution of 54ms. High resolution upslope and arrival time parametric maps were calculated from the acquired time series data, illustrating and quantifying regional differential ventilation. This technique could prove valuable in assessment and treatment planning for chronic obstructive lung diseases such as cystic fibrosis and asthma.

14:30 3688. Highly Constrained Backprojection (HYPR) for 3He-MRI Spontaneous Breathing and Insufflation Protocols in Rats Katarzyna Cieslar1, Achraf Al Faraj1, Vasile Stupar1, Sophie Gaillard1, Yannick Cremillieux1 1Creatis-LRMN, UMR CNRS, Université Lyon 1, LYON, France

High temporal resolution is particularly important in small animals studies due to high breathing rates of rodents. Angular undersampling of radially acquired data can increase the temporal resolution but results in poor image quality. HYPR reconstruction can be used to preserve high image SNR despite undersampling. We present the application of HYPR to 3He imaging of rats lungs. Visualisation of respiratory dynamics during insufflation and spontaneous breathing protocol was performed.

15:00 3689. Hyperpolarized-Gas Lung Imaging Using a Single-Shot Spiral Acquisition Hao Tan1, Weitian Chen1, Peng Hu1, G. Wilson Miller1, Talissa A Altes1, Jaime F Mata1, Eduard E de Lange1, Gordon D Cates1, Ray F. Lee2, Craig H. Meyer1, John Mugler III1 1University of Virginia, Charlottesville, Virginia , USA; 2New York University, New York, New York, USA

Hyperpolarized-gas MRI using 3He can provide quantitative information about lung structure and function. This noninvasive method is of great interest for studying lung diseases such as chronic obstructive pulmonary disease and asthma. In this study, we developed two single-shot spiral sequences towards that goal. In the first sequence, we used a preparation acquisition to obtain a field map before the imaging spiral readout. In the second sequence, we used a single-shot spiral with multiple gradient echoes and reconstructed images iteratively. Both sequences yielded reconstructed images with spatial resolution and image quality comparable to standard GRE images.

15:30 3690. Rapid Motion Mapping of Hyperpolarised Gas Flow Using K-T Subsampling Methods Xavier Maître1, Shaihan J. Malik2, Pascal Hagot1, Emmanuel Durand1, Luc Darrasse1, David J. Larkman2, Jacques Bittoun1 1CNRS (UMR8081), Univ. Paris-Sud, Orsay, France; 2Robert Steiner MRI Unit, London, UK

Hyperpolarised helium-3 imaging allows visualising airways during inhalation of the gas. Time-of-flight approaches have been developed to enable the high temporal resolution required to track the gas motion through the human airways with true 10 ms temporal resolution. The method is valid as long as the flow velocity remains constant over the total acquisition time. To suite physiological respiratory conditions, a 4-fold k-t undersampling of the dynamic images was performed and data reconstructed using k-t BLAST. Here, total acquisition times as low as 2.8 s were obtained in a mouth-trachea cast phantom with little loss in signal to noise ratio.

Bowel Imaging Hall D Monday 14:00-16:00

14:00 3691. Dynamic MRI Evaluation of Small Bowel Peristalsis Pattern Using Software: A Feasibility Study Sooah Kim1, Christophe ChefdHotel2, Laura Rueff1, Ruth P. Lim1, Vivian S. Lee1 1New York University, New York, New York, USA; 2Siemens Corporate Research, Princeton, New Jersey, USA

Ten patients referred for MR enterography were evaluated at 1.5 T using 2D dynamic steady state free precession sequence. 5 small bowel segments were selected per patient, and outer luminal diameter of each segment was measured manually on each dynamic images. Data were plotted over time. ROIs of same selected bowel segments were defined using semi-automated Fourier based software. Average temporal variance of the intensity values were plotted over time. Data and analysis time from both methods were compared, and both showed paralytic pattern of abnormal segments with inflammatory bowel disease. Normal bowel demonstrated periodic sinusoidal contraction. Analysis time per each patient was 20 minutes for manual and 1 minute for software. MRI assessment of small bowel peristalsis pattern using software provides a rapid assessment in inflammatory bowel disease.

14:30 3692. Factors Influencing Small Bowel Water Content: Fibre Intake, Fasting and Feeding Eleanor F. Cox1, Caroline L. Hoad1, Luca Marciani1, Robin C. Spiller1, Penny A. Gowland1 1University of Nottingham, Nottingham, UK

A novel MRI method was used to evaluate the effect of fibre content of an evening meal on the next morning’s fasting small bowel water content (SBWC) and to determine the effect on SBWC of switching from a fasting to a fed state. Feeding after overnight fasting caused a significant fall in SBWC, which continued to fall even after gastric emptying had begun. The fibre content of the previous night’s meal had no significant effect on SBWC measured the following morning. This important data will help understand the effects of fasting and feeding on the absorption and secretion of water in the small bowel.

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15:00 3693. Dynamic Contrast Enhanced MRI Evaluation of Small Bowel Crohn's Disease: A Correlation with Histopathologically Quantified Microvascular Density Shonit Punwani1, 2, Manuel Rodriguez-Justo2, Alan Bainbridge1, Enrico De Vita1, 2, Rebecca Greenhalgh2, Steve Halligan1, 2, Stuart Taylor1, 2 1University College London, London, UK; 2University College London Hospital, London, UK

The aim of this study was to assess quantitative and semi-quantitative in-vivo DCE-MRI parameters in predicting histopathologically quantified small bowel wall microvascular density (MVD) in resection specimens from patients with known ileal Crohn’s disease. In vivo DCE-MRI of disease affected bowel was performed pre-operation. Post surgical small bowel resection specimens were scanned to enable detailed imaging-histopathology matching. Histological sections were taken through the area of bowel corresponding to the DCE-MRI images. Quantitation of mural microvascular density (MVD) was performed with CD34 staining. DCE-MRI determined slope of enhancement was found to be strongly negatively correlated with MVD. SoE measurements may have potential in assessing disease and monitoring anti-angiogenic therapy in patients with Crohn’s disease affecting small bowel.

15:30 3694. Diffusion-Weighted Imaging in the MR Evaluation of Acute Abdominal Pain in Pregnancy Jesse L. Wei1, Martin P. Smith1, Neil M. Rofsky1, Ivan Pedrosa1 1Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA

Assessment of acute abdominal and pelvic pain in pregnancy is a challenge that is being addressed by the use of non-contrast MR imaging, including motion-insensitive T2W single-shot fast spin echo for anatomic assessment of structures; and T1W in-and-out of phase, T2W fat-suppressed, and time of flight imaging for characterization of structures based on intrinsic tissue contrast, flow, and susceptibility. We retrospectively analyze the utility of diffusion-weighted imaging as an additional imaging technique to provide another form of image contrast. We find that diffusion weighted images (b=1000) demonstrate increased signal intensity in 5 of 7 inflamed appendices in a population of 37 patients.

Body Diffusion & Whole Body Imaging Hall D Monday 14:00-16:00

14:00 3695. Respiratory Gated Body Diffusion Weighted Imaging (DWI) Avoiding Prolongation of Scan Time: Tracking Only Navigator Echo (TRON) Technique: Improvement for High B Value DWI Tomohiko Horie1, Tarou Takahara, Tetsuo Ogino, Tomoyuki Okuaki, Masatoshi Honda1, Isao Muro1, M.V. Cauteren, Yutaka Imai1 1Tokai University School of Medicine, Isehara, Japan

High b value DWI uses a long TE, which results in poor tracking due to increased time lag between navigator and slice excitation. Two software developments have recently been introduced. In this study, we investigated image quality and scanning time using the new TRON version at high b value. Image quality of new TRON was comparable to RT. Relative scanning time to FB was 104% with TRON and 272% with RT. The use of TRON concept and reduction of time lag in navigator sequence allows us practical high b value DWI in a short scan time.

14:30 3696. Combination of High-B-Value Diffusion-Weighted MRI and MR Cholangiopancreatography as the Optimal Non-Invasive Modality for Diagnosis of Pancreatic Adenocarcinoma Hiroki Haradome1, Akihisa Nakamura1, Shinju Suzuki1, Nobuaki Matumoto2, Toshiaki Nitatori1, You Atomi2 1Kyorin University School of Medicine., Mitaka, Tokyo, Japan; 2Kyorin University School of Medicine, Mitaka, Tokyo, Japan

Although contrast-enhanced dynamic multi-detector-CT have evolved as the mainstay for pancreatic cancer detection and staging, non-invasive modalities are desired for screening in risk groups of the pancreatic cancer, in particular. Both high-b-value diffusion-weighted MRI (DWI) and MR cholangiopancreatography (MRCP) is non-invasive modalities for detecting pancreatic cancer with a high sensitivity and specificity. We evaluated the utility of combination of DWI and MRCP for diagnosis of pancreatic adenocarcinoma. Combination of DWI and MRCP was the optimal non-invasive modality for diagnosis of pancreatic adenocarcinoma without radiation exposure and contrast agent.

15:00 3697. Prospective Comparison Multi Contrast with Diffusion Weighted Imaging Whole Body MRI, Whole Body PET-CT and Whole Body CT for Staging Advanced Melanoma valerie laurent1, 2, isabelle dufour claude3, pierre olivier1, pierre andre vuissoz, olivier bruot1, denis regent1, jacques felblinger2 1brabois hospital, vandoeuvre les nancy, France; 2H.Poincare university, vandoeuvre les nancy, France; 3general electric health care, BUC, France

Prospective study to compare multicontrast with DWI whole body MRI, whole body PET CT, whole body CT for staging advanced melanoma and to evaluate benefits of DWI sequence in addition oncologic MRI protocol. 38 patients were examined using multicontrast whole body MRI (STIR,T1w after contrast and DWI).The same day, whole body PET-CT et whole body CT were performed. Mc wb MRI with DWI was the most sensitive to detect lesions compared to PET CT and CT. The DWI permits to detect 20% supplementary lesions. The wb DWI is required in addition to T2w and T1w for oncologic whole body MRI

15:30 3698. High Resolution Whole-Body MRI Applications at 1.5 Tesla and 3 Tesla: A Comparative Study Gerwin P. Schmidt1, Bernd J. Wintersperger, Anno Graser, Andrea Baur-Melnyk1, Maximilian F. Reiser, Stefan O. Schoenberg 1University Hospitals Munich, Munich, Germany

WB-MRI is feasible at 3 Tesla and has comparably good image quality to 1.5 Tesla. Yet, 3 Tesla whole-body MRI shows significantly more artifacts, but with only mild to moderate impact on image assessment. Overall scan time is further reduced at 3 T with the use of PAT at constant image resolution.

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Iron Effects in Hepatic Imaging Hall D Monday 14:00-16:00

14:00 3699. High Speed Multiple Echo Acquisition (HISTO): A Rapid and Simultaneous Assessment of Fat and Iron Content in Liver by 1H-MRS Nashiely Pineda-Alonso1, Qin Xu1, Puneet Sharma2, Diego Martin3, Xiaoping Hu1 1Emory University, Atlanta, USA; 2Emory Clinic, Atlanta, USA; 3Emory University. School of Medicine, Atlanta, USA

Proton MR Spectroscopy (1H MRS) offers a means for noninvasively determining hepatic lipids (HL) and provides acceptable spectral resolution and high sensitivity even with low amounts of HL. 1H-MRS is also used to accurately quantify the iron overload in the liver. In this work, we introduce a technique that allows the rapid, accurate and simultaneous assessment of fat and iron content which could be applied for single breath hold liver MRS. The feasibility and accuracy of this technique has been demonstrated experimentally in phantoms and applied to patients with fatty liver disease.

14:30 3700. Effect of Superparamagnetic Iron Oxides on Hepatic Apparent Diffusion Coefficient at 3T in Human Subjects with Chronic Liver Disease Masoud Shiehmorteza1, Chad Andrew Kohl1, Sameer M. Mazhar1, Takeshi Yokoo1, Nicholas Pinto1, Richard Znamirowski Znamirowski1, Lillian O. Pacheco1, Michael S. Middleton1, Claude B. Sirlin1 1Liver Imaging Group, San Diego, California , USA

Iron accumulation may occur in chronic liver disease and by shortening T2* may alter tissue ADC values. To assess the potential effect of intrahepatic iron on ADC measurements, we compared the ADC values at 3T in 15 human subjects with chronic liver disease before and after superparamagnetic iron oxide (SPIO) administration. We found that administration of exogenous iron causes a mild but statistically significant elevation in hepatic ADC. We speculate that endogenous iron may have a similar effect and may modify the relation between ADC and fibrosis stage in chronic liver disease.

15:00 3701. Safety Assessment of Double-Contrast MR Imaging of Liver Disease Chad Andrew Kohl1, Sameer M. Mazhar1, Takeshi Yokoo1, Alyssa D. Chavez1, Nicholas Pinto1, Lillian O. Pacheco1, Jennifer Berry1, Zana Parman2, Tarek Hassanien2, Joel Lavine2, Jeffrey Schwimmer2, Claude B. Sirlin1, Michael Simca Middleton1 1Liver Imaging Group, San Diego, California , USA; 2UCSD, San Diego, California , USA

Double-contrast (SPIO/Gd) enhanced MR imaging has been used to assess hepatocellular carcinoma and liver fibrosis and may be more accurate for characterization of liver nodules than single-contrast MR imaging. Although each of these types of contrast agents are individually FDA-approved for MR imaging, their sequential use is not FDA-approved. Our aim is to assess the safety of sequential double-contrast MR imaging in patients with liver disease. Based on prospective data from 56 subjects there is no greater risk with sequential use of Feridex® and Magnevist® than with individual use of either agent alone.

15:30 3702. Spleen R2 and R2* in Iron Overloaded Patients with Sickle Cell Disease and Thalassemia Major Casey John Brewer1, Thomas D. Coates1, John C. Wood1 1Childrens Hospital Los Angeles, Los Angeles, California , USA

Many sickle cell disease (SCD) and thalassemia major (TM) patients require chronic blood transfusions that result in massive iron overload of their organ tissues. MRI has been used to quantify organ iron but little study has been done on the spleen. We quantified splenic iron in SCD and TM patients by retrospectively analyzing their hepatic MR scans. Splenic R2 was attenuated relative to R2* and SCD patients loaded more iron into their spleens than TM patients. It is concluded that splenic R2 and R2* have a different relationship than do liver R2 and R2* and that the spleen is a major site of iron loading in SCD but not TM patients.

Hepatobiliary Hall D Tuesday 13:30-15:30

13:30 3703. Perfusion MRI of the Whole Liver Using 4D Thrive: Feasibility of Focal Liver Lesion Characterization Using Parametric Maps Kenneth Coenegrachts1, Johan Ghekiere1, Vincent Denolin2, Gabriele Beck3, Gwen Hérigault3, Marc Haspeslagh1, Peter Daled1, Shandra Bipat4, Jaap Stoker4, Hans Rigauts1 1AZ St.-Jan AV, Brugge, Belgium; 2Philips Medical Systems, Benelux, Belgium; 3Philips Medical Systems, Best, Netherlands; 4Academic Medical Center, Amsterdam, Netherlands

In this preliminary study, the presented 4D THRIVE sequence seems feasible for perfusion-based T1w CE-MRI and allows calculation of parametric maps. The 4D THRIVE sequence seems promising for the qualitative differentiation of malignant and benign focal liver lesions using parametric maps. Although T1w CE-MRI has been used for perfusion imaging of the liver this technique remains developmental and the best measurement method is still to be determined. Once the methodology is established, rigorous multi-observer studies will be required to validate perfusion MRI and determine its impact on the ability to differentiate malignant from benign liver lesions.

14:00 3704. SPIO-Enhanced FLAIR Echo-Planar Imaging in the Depiction of Hepatic Malignant Tumors: Comparison with T2-Weighted Fast Spin-Echo and T2*-Weighted Fast Field-Echo Imaging Yoshihiko Fukukura1, Takuro Kamiyama, Ryutaro Higashi, Koji Takumi, Toshikazu Shindo, Masayuki Nakajo 1Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan

SPIO-enhanced echo-planar FLAIR images showed higher accuracy in the detection of hepatic malignant tumors.

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14:30 3705. Usefulness of Superparamagnetic Iron Oxide-Enhanced T1-Weighted Echo-Planar MR Imaging for Assessment of Positive Enhancement in Hepatic Hemangioma Nagaaki Marugami1, Satoru Kitano1, Shinji Hirohashi2, Junko Takahama1, Kimihiko Kichikawa1 1Nara Medical University, Kashihara, Japan; 2Gyoumeikan Hospital, Osaka, Japan

SPIO-enhanced T1-weighted Echo-plannar MR imaging is useful in diagnosis of hepatic hemangioma with the finding of positive enhancement.

15:00 3706. Variable Performance of Chemical Shift-Based Multipoint Water-Fat Separation MRI and Its Impact on the Diagnosis of Fatty Liver Hyeonjin Kim1, Sara E. Taksali, Sylvie Dufour, Douglas Befroy, T Robin Goodman1, Kitt Falk Petersen, Gerald I. Shulman, Sonia Caprio, R Todd Constable1 1Yale University School of Medicine, New Haven, Connecticut, USA

In this report we address the variable performance of chemical shift-based multipoint water-fat separation MRI and its influence on the diagnosis of fatty liver in 28 humans by using 1H-MRS as a reference, 2-point Dixon and 3-point IDEAL. Our results demonstrate that the performance of multipoint water-fat separation MRI significantly depends on the choice of sampling strategy, post-data processing algorithm and pulse sequence. Therefore, to minimize errors in the diagnosis of fatty liver using multipoint water-fat separation MRI, it may be necessary to establish a cutoff fat content for normal liver specific to each imaging protocol¡¯s sequences and sequence parameters.

13:30 3707. Dynamic Gadolinium-Enhanced Liver Imaging Using LAVA Dual Echo with Water Reconstruction Russell Norman Low1, 2, Scott Boles2, Neeraj Panchal2 1Sharp and Children's MRI Center, San Diego, California , USA; 2San Diego Imaging, San Diego, California , USA

LAVA-IDEAL generates water images from a dual echo 3D FSPGR acquisition using a 2-point Dixon reconstruction algorithm. Dynamic liver imaging with LAVA-IDEAL during the arterial and portal venous phases is characterized by nearly perfect separation of fat and water signal, images with high contrast, minimal artifacts and excellent depiction of liver lesions.

14:00 3708. Hepatic Steatosis Results in a Reduction in the Apparent Diffusion Coefficient (ADC) of Liver Parenchyma Oliver Wignall1, Erica Scurr1, David Collins2, Choon-Hua Thng3, Dow-Mu Koh2 1Royal Marsden Hospital, Sutton, UK; 2Institute of Cancer Research, Sutton, UK; 3National Cancer Centre, Singapore, Singapore

This study compares the ADC values of liver parenchyma in areas with and without fatty infiltration as determined by in-phase and opposed-phase T1-weighted MR imaging. The mean ADC of areas of fatty infiltration is significantly lower than that of normal liver. A linear relationship was established between ADC and the percentage of fat infiltration as estimated by the ratio of in-phase and opposed-phase signal intensities in steatotic liver. This has implications for DWI assessment of diffuse liver disease.

14:30 3709. Noninvasive Evaluation of Nonalcoholic Fatty Liver Disease (NAFLD) Using 1H and 23Na Magnetic Resonance Imaging and Spectroscopy in a Rat Model Paige Nicole Hopewell1, 2, Navin Bansal1 1Indiana University School of Medicine, Indianapolis, Indiana, USA; 2Purdue University, West Lafayette, Indiana, USA

With increasing prevalence of the metabolic syndrome, non-alcoholic fatty liver disease (NAFLD) is now the most common chronic liver disease in humans. This study employed extensive lipid profiling via 1H MRS to demonstrate temporal changes in lipid content, resolving 8 lipid resonance peaks plus water in vivo, with water- and fat-suppressed 1H MRI. Single-quantum- (SQ) and multiple-quantum-(MQF) filtered 23Na MRI were employed to evaluate cellular energy status as NAFLD progressed in a MCDD rat model.

15:00 3710. Overestimation of Liver Fat Content in Fast Dixon-Based MRI Method Compared with Multi-Voxel MR Spectroscopy Quantification Paul E. Sijens1, Mireille A. Edens1, Roy Irwan1 1UMCG, Groningen, Netherlands

A recently published Dixon-based MRI method for quantifying liver fat content using dual-echo breath-hold gradient echo imaging was validated by phantom experiments and compared with results of biopsy in two patients [Radiology 2005;237:1048-1055]. We applied this method in ten healthy volunteers and compared the outcomes with the results of MR spectroscopy (MRS), the gold standard in quantifying liver fat content. Novel was the use of spectroscopic imaging yielding the variations in fat content across the liver rather than a single value obtained by single voxel MRS. Compared with results of MRS, liver fat content according to MRI was too high in nine subjects (range 3.3-10.7% vs. 0.9-7.7%) and correct in one (21.1 vs. 21.3%). Furthermore, in one of the ten subjects the MRI fat content according to the Dixon-based MRI method was incorrect due to a (100-x) versus x percent lipid content mix-up. Despite systematic overestimation of liver fat contents by MRI, Spearman's correlation between the (in 1 case adjusted) MRI liver fat contents with MRS was high (r = 0.927, P < 0.001). The problem with the Dixon-based MRI method for the assessment of liver fat content, is that, at the lower end range, liver fat content is systematically overestimated by approximately 3%.

13:30 3711. Rapid Evaluation of Liver Fat Content Using In-Out-Phase Imaging in Nonalcoholic Fatty Liver Disease Ronald Borra1, 2, Sakari Salo1, Kirsti Dean1, Riikka Lautamäki2, Pirjo Nuutila2, Markku Komu1, Riitta Parkkola1, 2 1Turku University Hospital, Turku, Finland; 2University of Turku and Turku University Hospital, Turku, Finland

This study shows the possibilities for liver fat content (LFC) quantification with in-out-phase imaging in patients with type 2 diabetes, at high risk for nonalcoholic fatty liver disease (NAFLD). Signal intensity differences between in-phase and out-phase images were correlated linearly with 1H MRS measurements of LFC (P<0.001, r=0.94) and provided a cut-off point at 5.1%, the normal upper limit for LFC. Our findings suggest that in-out-phase imaging can be used for rapid and reliable discrimination between normal or increased LFC in patients with NAFLD.

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14:00 3712. Human Liver Transplant Graft Steatosis: Evaluation with MRI David John Lomas1, Kieren G. Hollingsworth1, Richard T. Black1, Jane C. Smith1, Toby Prevost2, Chris J. Watson1, Neville V. Jamieson1, Graeme J. Alexander1, Alexander E. Gimson1 1University of Cambridge & Addenbrooke's Hospital, Cambridge, UK; 2University of Cambridge, Cambridge, UK

Steatosis in donor liver grafts adversely affects outcome in human transplantation. This study investigates whether rapid MRI steatosis quantification in ex-vivo grafts, immediately prior to transplantation, correlates firstly with the currently used surgical “eyeball” and subsequent pathology “time zero” biopsy assessment; and secondly with the biochemical parameters measured in the first week post transplant that reflect early graft performance. Thirty nine grafts were examined and MRI quantification correlated significantly with the other two assessments but was the only one of the three to correlate significantly with any of the serum markers of early graft performance.

14:30 3713. Quantification of Hepatic Steatosis with MRI: Correction for Bias from Noise and T1 Chia-Ying Liu1, 2, Charles A. McKenzie2, Huanzhou Yu3, Jean H. Brittain4, Scott Brian Reeder1 1University of Wisconsin-Madison, Madison, Wisconsin, USA; 2University of Western Ontario, London, Canada; 3GE Healthcare, Menlo Park, California , USA; 4GE Healthcare, Madison, Wisconsin, USA

Quantification of hepatic steatosis is a significant unmet need for the diagnosis and treatment monitoring of patients with non-alcoholic fatty liver disease. MRI is capable of separating water and fat signals to quantify steatosis. Unfortunately, the non-zero mean noise in magnitude images and confounding T1 effects can lead to incorrect estimation of the true fat fraction. We demonstrate two approaches to reduce noise bias: magnitude discrimination and phase-constrained reconstruction, and two methods to reduce T1 bias: small flip angle and dual flip angle method. Bias on fat-fraction estimates was minimized using these methods.

15:00 3714. Liver Steatosis Quantification Using MRI: A Prospective Comparative Study with Liver Biopsy nicolas mennesson1, Jérôme Dumortier1, Sophie Cavassila2, Olivier Beuf2, Jean-Yves Scoazec3, Frank Pilleul, 12 1Hospices Civils de Lyon, Lyon, France; 2INSA-Lyon, Université Lyon 1, Villeurbanne, France; 3Faculté de médecine RTH Laennec, Lyon, France

The diagnosis of steatosis does have important therapeutic implications, because active management of obesity and a reduction in steatosis may improve liver injury and decrease the progression of fibrosis. Double-echo imaging (DEI) such as simple method have been used in order to substitute liver biopsy which is the gold standard. For this study, forty patients with suspected chronic liver diseases were prospectively investigated by MR imaging and liver biopsy. The fat/water ratio had a positive correlation with steatosis grade on liver biopsy (p < 0.0001), the coefficient of linear regression corresponding to r = 0.798. So, Fat/Water ratio (cutoff value ¡Ý at .93) revealed liver steatosis defined by the presence of equal or more 20 % of intracellular lipids with a sensitivity of 93 % and a specificity of 86 %.

13:30 3715. Characterization of Liver Fibrosis Using Fat-Suppressed Ultrashort TE (FUTE) Imaging and Multipoint Water-Fat Separation MRI in Patients with Hepatitis C Virus (HCV)-Induced Liver Fibrosis Hyeonjin Kim1, Matthew D. Robson2, Maolin Qiu1, Jinghua Wang1, Joseph K. Lim, Philip S. Murphy3, R Todd Constable1 1Yale University School of Medicine, New Haven, Connecticut, USA; 2John Radcliffe Hospital, Oxford, UK; 3Pfizer, Sandwich, UK

The feasibility of ultrashort echo time (UTE) imaging in assessing liver fibrosis was explored in patients with different stages of hepatitis C virus (HCV)-induced liver fibrosis. As hepatic steatosis and concomitant iron overload are common features in many chronic liver diseases, the quantification of hepatic fat content and T2* mapping are also performed and their effect on the quantification of short T2 components is addressed. Our results suggest that fat-suppressed UTE (FUTE) imaging may potentially provide a means of non-invasively discriminating the end stage of liver fibrosis from its milder forms in the presence of steatosis and/or iron overload.

14:00 3716. Correlation Between Different Stages of Hepatic Fibrosis and in Vivo Metabolic Profile by 1H Magentic Resonante Spectroscopy Beatriz Martínez-Granados1, M. Carmen Carmen Martínez-Bisbal1, 2, Daniel Monleón3, Luís Martí-Bonmatí4, José Manuel Manuel Rodrigo3, Juan del Olmo3, Antonio Ferrández3, Bernardo Celda1, 2 1Universitat de Valencia, Burjassot, Spain; 2ISC III, Burjassot, Spain; 3Hospital Clínico Universitario, Valencia, Spain; 4Hospital Universitario Dr. Peset, Valencia, Spain

The aim of this study is to verify the potential clinical applications of in vivo liver 1H-MRS metabolic alterations for improving the diagnosis of different liver fibrosis stage. MRS 1.5T (SV at TE=136 ms) studies were performed in 50 patients with clinical fibrosis. Different resonances (lipids, choline, TMAO and glucose) were assigned and identified using ex vivo HR-MAS (11T) and literature data. Statistical significant differences between (-CH3 lipid)/H2O and (glucose+-CH=CHCH2- lipid+glycogen)/H2O ratios and the four fibrosis stages were found. The in vivo liver 1H-MRS profiles and their correlation with fibrosis adds non-invasively quantitative metabolic information to liver pathology diagnosis.

14:30 3717. Effect of Autologous Bone Marrow Cell Infusion Therapy in Patient with Liver Cirrhosis on Ferucarbotran-Enhanced MR Imaging: A Preliminary Report Mi-Suk Park1, Ja Kyung Kim 1Yonsei University, Severance Hospital, Seoul, Republic of Korea

Our study is an initial, preliminary report about the effect of ABMI therapy in the patients with liver cirrhosis on ferucarbotran-enhanced MR Imaging. There was a gradual reduction of SPIO uptake after ABMI with increase of liver volume and serum albumin level, which might reflect the progenitor cell proliferation and reduction in Kupffer cell. However, further investigation with contrast agents tagging with bone marrow cells may be needed to evaluate the precise effect of ABMI therapy in the patients with liver cirrhosis.

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15:00 3718. Non-Invasive Diagnosis of Liver Fibrosis - Comparison Between MR Elastography and Supersonic Imaging in an Animal Study Najat Salameh1, Jean-Luc Gennisson2, Benoit Larrat2, Thomas Deffieux2, Michael Tanter2, Ralph Sinkus2, Bernard Edgard Van Beers1, Mathias Fink2 1Université Catholique de Louvain, Brussels, Belgium; 2Laboratoire Ondes et Acoustiques, Paris, France

In this study, we validate the Supersonic Shear Imaging method, by comparing the elasticity measurements obtained with SSI to those obtained with MRE in a model of dietary steatohepatitis in the rat. The elastography measurements were correlated to the percentage of fibrosis obtained at morphometry.

13:30 3719. Quantification of SPIO Enhancement Measured by T2 and T2* Mapping in Chronic Liver Disease: A Preliminary Report Yong Eun Chung1, Mi-Suk Park1, Eun Ju Kim, Myoung Soo Kim1, Hua-Sun Kim1, Myeong-Jin Kim1, Jin-Young Choi1, Ki Whang Kim1 1Yonsei University Health System, Seoul, Republic of Korea

This study evaluate feasibility of T2 and T2 mapping on pre- and post-contrast multi echo fast field echo sequence in chronic liver disease patient.

14:00 3720. MR Imaging Findings in Patients with Hereditary Hemorrhagic Telangiectasia and Liver Involvement Guenther K. Schneider1, Alexander Massmann2, Miles A. Kirchin3, Roland Seidel1, Peter Fries1, Urban W. Geisthoff4, Arno Buecker1 1Saarland University Hospital, Homburg/Saar, Germany; 2Saarland University Hospital,, Homburg/Saar, Germany; 3Bracco Imaging S.p.A., Milan, Italy; 4Hospitals of the City of Cologne, Cologne, Germany

Hereditary hemorrhagic telangiectasia (HHT) also known as Rendu-Osler-Weber disease is an autosomal-dominant inherited vascular disorder associated with mucocutaneous, pulmonary, cerebral and visceral arteriovenous malformations. Hepatic affection of HHT results in a wide spectrum from discrete changes of the liver parenchyma and hepatic vessels to high morbidity and mortality due to right heart insufficiency. The study shows the variety of different HHT-related findings in the liver on magnetic resonance imaging and magnetic resonance angiography: hepatomegalia, nodular hyperplastic changes of the liver parenchyma, dilated tortuous intrahepatic vessels, increased hepatic artery and portal vein diameter as well as right heart insufficiency.

14:30 3721. T1-Weighted DCE MRI with Gd-EOB-DTPA as a Liver Function Test: A Comparison of Two Methods for Deconvolutional Analysis Henrik Nilsson1, Anders Nordell2, Lena Douglas2, Roberto Vargas3, Eduard Jonas1, Lennart Blomqvist3 1Karolinska Instiutet, Stockholm, Sweden; 2Karolinska University Hospital, Stockholm, Sweden; 3Institution for Molecular Medicine and Surgery Karolinska Institutet, Stockholm, Sweden

The aim of this study was to assess the feasibility to use dynamic T1-weighted Gd-EOB-DTPA-enhanced MRI for the evaluation of segmental liver function in 20 healthy human volunteers. Hepatic Extraction Fraction (HEF), earlier described and used in hepatobiliary scintigraphy, was chosen as marker of hepatocyte function. For deconvolutional analysis (DA), Fourier transforms with an appended tail and Singular Value Decomposition (SVD) were used. The results obtained with the two methods for DA were compared. We found that it is possible to calculate HEF on a segmental level, and that the two methods yields similar results without significant differences.

15:00 3722. Evaluation of Superparamagnetic Iron Oxide (SPIO) Particles for MR Imaging of Nonalcoholic Steatohepatitis (NASH) Akihiro Tanimoto1, Kengo Tomita1, Rie Irie1, Koichi Oshio1, Sachio Kuribay1 1Keio University School of Medicine, Tokyo, Japan

To determine whether SPIO-enhanced MRI can help to detect NASH, we evaluated 19 patients with nonalcoholic fatty liver disease (NAFLD). Liver biopsy proved ten of 19 patients were definitive NASH. MRI consisting of T2-FSE, T2*-GRE, and EPI was performed prior to biopsy. Relative signal decrease [%T2 and %T2*] caused by SPIO were smaller in NASH group than in not NASH group. The time constant τ from exponential approximation of signal decay on EPI was larger in NASH group than in not NASH group. SPIO-enhanced MRI would be a reliable tool to identify NASH patients among the patients having NAFLD.

13:30 3723. Depiction of Non-Dilated Intrahepatic Bile Duct by High Spatial Resolution 3D MR Cholangiography Using SPACE at 3 T; Comparison with 1.5 T in Healthy Volunteers Shigeki Arizono1, Hiroyoshi Isoda1, Yoji Maetani1, Yuusuke Hirokawa1, Kotaro Shimada1, Yuji Nakamoto1, Kaori Togashi1 1Kyoto University Graduate School of Medicine, Kyoto, Japan

SPACE is a new technique that could overcome SAR problem on 3D TSE sequence at 3T by using variable refocusing FA, while maintaining better SNR. Applying the SPACE technique at 3T, high spatial resolution 3D MRC can be obtained without running into SAR problem. In this presentation, we described the superiority of 3D MRC with SPACE at 3 T over MRC with conventional constant FA at 3T or MRC at 1.5T. In addition, we showed that high resolution 3D MRC with SPACE at 3T allows high-quality images of biliary tract, and has the ability to depict non-dilated intrahepatic bile ducts.

14:00 3724. Navigator-Triggered Prospective Acquisition Correction (PACE) Technique vs. Conventional Respiratory-Triggered Technique for Free-Breathing 3D MRCP: Prospective Comparative Study Using Healthy Volunteers Satoru Morita1, Eiko Ueno1, Kazufumi Suzuki1, Haruhiko Machida1, Mikihiko Fujimura1, Shinya Kojima1, Masami Hirata1, Takahiro Ohnishi2, Chiaki Imura2 1Tokyo Women's Medical University Medical Center East, Tokyo, Japan; 2Siemens-Asahi Medical Technologies, Tokyo, Japan

This study sought to confirm the superiority of navigator-triggered prospective acquisition correction (PACE) technique over the conventional respiratory-triggered (RESP) technique. This has been perceived experimentally, but without definite evidence, for free-breathing 3D MRCP. Images from free-breathing 3D turbo spin-echo MRCP using both PACE and RESP techniques were prospectively performed on 25 healthy volunteers. Qualitative and quantitative analyses of contour sharpness index both revealed the image quality of PACE technique to be significantly better than RESP. The superiority of PACE to conventional RESP for free-breathing 3D MRCP with regard to the image quality was confirmed.

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14:30 3725. Respiratory Triggered High-Spatial Resolution T1-Weighted MR Imaging of Liver and Biliary Tree in the Hepatobiliary Phase Patrick Asbach1, Carsten Warmuth2, Matthias Rief1, Matthias Taupitz1, Bernd Hamm1, Christian Klessen1 1Charité - Universitaetsmedizin Berlin, Berlin, Germany; 2Siemens Medical Solutions, Erlangen, Germany

Hepatobiliary contrast media have the potential to increase the diagnostic performance of magnetic resonance imaging of the liver. The hypothesis for this study was that respiratory triggered high-spatial resolution images acquired in the hepatobiliary phase provide significantly increased image quality compared to breath-hold images. A quantitative and qualitative analysis was performed in 20 patients comparing a respiratory triggered T1w inversion prepared spoiled gradient echo sequence to a breath-hold T1w spoiled gradient echo sequence. The respiratory triggered high-spatial resolution images provide a significantly increased image quality in comparison to breath-hold images on the expense of extended acquisition time.

15:00 3726. Biliary Anatomy on 3D MRCP Using Free-Breathing Navigator-Triggered Prospective Acquisition Correction: Comparison of Volume-Rendering and Maximum-Intensity-Projection Algorithm Satoru Morita1, 2, Naoko Saito3, Kazufumi Suzuki1, Haruhiko Machida1, Mikihiko Fujimura1, Eiko Ueno1, Norio Mitsuhashi4, Takahiro Ohnishi5, Chiaki Imura5 1Tokyo Women's Medical University Medical Center East, Tokyo, Japan; 2Saiseikai Kurihashi Hospital, Saitama, Japan; 3Boston Medical Center, Boston University School of Medicine, MA, USA; 4Tokyo Women's Medical University, Tokyo, Japan; 5Siemens-Asahi Medical Technologies, Tokyo, Japan

This study sought to compare VR and MIP as postprocessing techniques of 3D MRCP to define biliary anatomies. VR and MIP images of 3D MRCP using a prospective acquisition correction technique for 102 patients were retrospectively evaluated by two radiologists in a blinded fashion independently. Interpretation confidence and the accuracies of each reformation with the reference standard were compared. VR findings agreed with the reference standard findings more often than MIP with regard to cystic duct variation. Mean confidence score was significantly higher with VR than MIP with regard to both cystic duct variation and biliary branching patterns. VR reformation of 3D MRCP defines biliary anatomies more accurately than MIP.

13:30 3727. k-TE GRAPPA for Rapid Abdominal R2* Mapping Xiaoming Yin1, 2, Andrew C. Larson1, 2 1Northwestern University, Chicago, Illinois, USA; 2Evanston, Illinois, USA

R2* measurements have proven useful for abdominal imaging applications. The commonly used multiple-GRE (MGRE) sequence collects a train of echoes thereby permitting the reconstruction of images at each TE and subsequent derivation of R2* maps. However, spatial resolution remains to be a challenge to breath-hold requirements. Based upon an extension of k-t GRAPPA parallel imaging methods we recently developed a k-TE GRAPPA approach to reduce MGRE scan times. It has been found that k-TE GRAPPA is an effective parallel imaging method to accelerate MGRE R2*-mapping. It reduced artifact levels and provided more accurate R2* measurements compared to VS and GRAPPA approaches. k-TE GRAPPA offers the potential to reduce breath-hold times and/or increase spatial resolution or coverage.

14:00 3728. Safety of MR Imaging of the Liver with Ferucarbotran: Multicenter Investigation Using Questionnaire Before and After an Examination Hiromitsu Onishi1, Takamichi Murakami2, Tonsok Kim1, Masatoshi Hori1, Mitsuru Matsuki, Shinji Hirohashi, Yasuharu Imai, Kousuke Sakurai, Yoshifumi Narumi, Hironobu Nakamura1 1Osaka University Graduate School of Medicine, Suita, Japan; 2Kinki University, Osakasayama, Japan

We prospectively investigated the incidence of adverse reactions of ferucarbotran, a superparamagnetic iron oxide contrast agent, using a questionnaire style. Three hundred fifteen patients who underwent ferucarbotran-enhanced magnetic resonance imaging were given a questionnaire asking about the symptoms over a period of 7 days before and after injection of ferucarbotran in order to estimate the false positive adverse reactions. The adverse events to ferucarbotran which were classified as possibly or definitely ferucarbotran related occurred in 14.3%. All of adverse reactions were mild of intensity. Ferucarbotran was considered to be safe in the clinical use at MR imaging of the liver.

14:30 3729. Discrimination of Pancreaticohepatobiliary Cancer and Benign Patients in Presence and Absence of Jaundice and Cholangitis: 1H and 31P NMR Studies of Bile Lakshmi Bala1, Pratima Tripathi1, Raja Roy1, Gourdas Choudhuri2, Chunni Lal Khetrapal1 1Sanjay Gandhi Post-Graduate Institute of Medical Sciences Campus, LUCKNOW, India; 2Sanjay Gandhi Post-Graduate Institute of Medical Sciences, LUCKNOW, India

1H and 31P NMR quantitative analysis of bile specimens from pancreaticohepatobiliary cancer (n=28) and benign patients (n=20) (with/without jaundice and cholangitis) were carried out for chief biliary constituents viz. total bile acids (TBA), cholesterol (Chol.), phosphatidylcholine (PtC) and inorganic phosphate (Pi). Presence of jaundice and cholangitis significantly lowered biliary constituents (p<0.05 for all) in both benign and malignant patients, possibly due to the down regulation of function of tranporters located at the canalicular side of hepatocytes. Hence, presence of jaundice and cholangitis reduces biliary constituents in bile in benign resulting them indiscriminant with malignant without jaundice and cholangitis.

15:00 3730. Respiratory Self-Gated Phase-Contrast MRI for Free-Breathing Flow Measurements in the Portal Venous System Ning Jin1, Andrew C. Larson1, 2 1Northwestern University, Chicago, Illinois, USA; 2Robert H. Lurie Comprehensive Cancer Center, Chicago, Illinois, USA

Breath hold is commomly needed for abdominal phase contrast (PC) flow measurement to remove the respiratory motion. However, the scan times may be prohibitive for cardiac-gated high-resolution imaging. Also for some ill patients, they may be unable to comply with breath hold commands. Some alternative free-breathing methods may be beneficial. Self-gating approaches with additional central k-space lines sampled to track respiratory motion have been applied in cardiovascular and abdominal imaging with free breathing. In this abstract we developed a respiratory self-gated imaging strategy for free breathing abdominal PC flow measurements and compared this technique to conventional breath-hold PC flow measurement in the portal venous system.

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Advances in GI & Hepatobiliary Imaging Hall D Tuesday 13:30-15:30

13:30 3731. Diffusion Weighted MR Imaging of Gastric Cancer: Comparison with Conventional MRI Sequences Lei Tang1, Xiao Peng Zhang1, Ying Shi Sun1, Kun Cao1, Jie Li1, Ning Wang1, Fei Sun2 1Beijing Cancer Hospital & Peking University School of Oncology, Beijing, People's Republic of China; 2GE healthcare China, Beijing, People's Republic of China

MRI examinations were performed on 31 patients with gastric cancer. Three diffusion-weighted sequences were designed with different b values. Free water grade was used to evaluate the suppression of content signal in gastric lumen. SNR and SIR of high b-value DWI and conventional MRI sequences were calculated and compared. High b-value DWI could demonstrate signal differences better. The ADCs of gastric cancer were decreased following the increase of b-value. The CNR and SIR of high b-value DWI were higher than that of T1WI and T2WI. DWI can be a supplementary method for conventional MRI examinations to demonstrate gastric cancer better.

14:00 3732. Utility of Ferucarbotran-Enhanced T1-Weighted Spoiled Gradient Recalled Echo MR Images for Hepatic Metastases: A Prospective Comparison with 3.0 T and 1.5T Masakatsu Tsurusaki1, Keitaro Sofue1, Mototaka Miyake1, Aine Sakurada1, Ukihide Tateishi1, Yasuaki Arai1, Kazuro Sugimura2 1National cancer center, Tokyo, Japan; 2Kobe University, Graduate school of medicine, Kobe, Japan

To prospectively compare the frequency and qualitative efficacy of gring enhancementh on ferucarbotran-enhanced T1-weighted GRE images using 3.0 T to 1.5T for the detection of hepatic metastases. A total of 25 patients with 70 hepatic metastases underwent ferucarbotran-enhanced MR imaging using both 3.0T and 1.5T scanner. The frequency of gring enhancementh in hepatic metastases at 3.0T (74.2%) was significantly (p<0.05) higher than at 1.5T (55.7%) on ferucarbotran-enhanced T1-weighted GRE images. On T1-weighted GRE images, gring enhancementh is shown more frequent at 3.0T than 1.5T. Therefore, it is also helpful sign for characterizing hepatic metastases in ferucarbotran-enhanced MR images.

14:30 3733. Ferucarbotran-Enhanced Magnetic Resonance Imaging in Patients with Hepatic Metastases: Prospective Quantitative and Qualitative Comparison of 3.0 T and 1.5T Keitaro Sofue1, Masakatsu Tsurusaki1, Mototaka Miyake1, Aine Sakurada1, Ukihide Tateishi1, Yasuaki Arai1, Kazuro Sugimura2 1National Cancer Center Hospital, Tokyo, Japan; 2Kobe University, Graduate School of Medicine, Kobe, Japan

To prospectively compare quantitative and qualitative efficacy of ferucarbotran-enhanced MR imaging using 3.0 T to 1.5T for the detection of hepatic metastases. Using 3.0T, ferucarbotran-enhanced MRI showed higher sensitivity than the images using 1.5T for the detection of hepatic metastases. On ferucarbotran-enhanced MRI using 3.0T, higher SNR and lesion-to-liver CNR were achieved than 1.5T, moreover, the decreasing of motion artifact and the improvement of overall image quality on T2*-weighted GRE images using 3.0T might contribute the higher sensitivity.

15:00 3734. Evaluation of Quantitative Dynamic Contrast Enhanced Pharmacokinetic Parameters with and Without Postprocessing Alignment Keiko Miyazaki1, David J. Collins1, Dow-Mu Koh1, David Atkinson2, David J. Hawkes2, Martin O. Leach1 1Institute of Cancer Research, Sutton, UK; 2University College London, London, UK

Dynamic imaging in the liver is a major challenge particularly in accounting for mis-alignments and deformation of the liver. In this paper, the effects of mis-alignment effects in a clinical DCE-MRI liver protocol which involved successive full-exhale breath-holds was evaluated by analyzing the pharmacokinetic (PK) parameters with and without post-processing alignment. DCE-MR protocols which are robust to mis-alignments in the organs would assist accurate derivation of quantitative PK parameters which are increasingly used in several clinical setting to monitor disease progression and regression.

13:30 3735. Diagnosis of Liver Metastatic Lesions: Performance of Diffusion-Weighted Imaging Compared to Contrast-Enhanced T1-Weighted Imaging Andrew D. Hardie1, Mohit Naik1, Elizabeth M. Hecht1, Hersh Chandarana1, Vivian S. Lee1, Bachir Taouli1 1NYU Medical Center, New York, New York, USA

With the recently described risks of gadolinium exposure in patients with poor renal function, optimization of non-gadolinium enhanced sequences is essential. This study compares the accuracy of diffusion-weighted imaging (DWI) compared to Gadolinium-enhanced T1 sequence for diagnosis of liver metastases in patients with primary cancer. Sensitivity of the DWI and Gd-enhanced datasets were both 81% while the specificity was 78% for DWI and 89% for Gd-enhanced T1. This preliminary study demonstrates the potential role of DWI as an alternate method for the assessment of focal liver lesions in oncology patients in whom gadolinium is contraindicated.

14:00 3736. 1H MRS of Human Bile in the Differential Diagnosis of Cholangiocarcinoma and Pancreatic Cancer Tedros Bezabeh1, Omkar B. Ijare1, Nils Albiin2, Urban Arnelo2, Bo Lindberg2, Ian C.P. Smith1 1National Research Council Institute for Biodiagnostics, Winnipeg, Canada; 2Karolinska Institutet, Stockholm, Sweden

Bile is a biofluid of choice for the study of pancreaticobiliary malignancies such as cholangiocarcinoma, gallbladder cancer and pancreatic cancer. In the course of these malignancies, the biochemical composition of bile alters as a result of increased cell turnover. In the present study, the biochemical composition of bile was compared in two pancreaticobiliary malignancies – cholangiocarcinoma and pancreatic cancer, making use of 1H MRS. The study revealed that cholangiocarcinoma patients showed a decrease in biliary biochemicals such as bile salts, phosphatidylcholine and cholesterol compared to the normal reference patients. Furthermore, most of the bile samples showed the absence of some conjugated bile salts and phosphatidylcholine. On the contrary, in pancreatic cancer, biliary lipid components were intact, but a carbohydrate moiety, D-glucuronate, was predominantly observed in the bile.

14:30 3737. Effect of Intravenous Superparamagnetic Iron Oxide on Diffusion-Weighted Imaging Nagaaki Marugami1, Satoru Kitano1, Shinji Hirohashi2, Megumi Takewa1, Junko Takahama1, Aki Takahashi1, Kimihiko Kichikawa1 1Nara Medical University, Kashihara, Japan; 2Osaka Gyoumeikan Hospital, Osaka, Japan

Superparamagnetic iron oxide injection had significant effects on ADC values. Therefore, only pre-contrast diffusion-weighted images should be used on quantitative ADC studies.

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15:00 3738. ROC Comparison Between Diffusion-Weighted MR and PET/CT Imaging to Detect Lymph Node Metastasis from Gastrointestinal Cancer Hitoshi Kubo1, Masafumi Harada1, Tatsuro Goto1, Masaaki Ikeguchi1, Mayumi Takeuchi1, Hiromu Nishitani1 1University of Tokushima, Tokushima, Japan

The usefulness of diffusion-weighted MR imaging (DWI) to detect lymph node metastasis from the gastrointestinal cancer was evaluated by ROC analysis in comparison with 18F-FDG imaging (PET). We analyzed 21 patients examined both DWI and PET in our Hospital. The sensitivity of DWI was higher but the specificity was lower than those of PET. The ROC analysis showed higher accuracy on DWI than PET, though the variation of individual evaluation on DWI was larger than that on PET depending on the experience of imaging diagnosis by observers.

13:30 3739. Comparison in Functional and Metabolic MR Imaging Findings Between Targeted and Non-Targeted Unresectable Hepatic Tumors Treated with TACE Ihab R. Kamel1, Josephina A. Vossen, Manon Buijs, Nouha Salibi, David A. Bluemke, Jean-Francois H. Geschwind 1Johns Hopkins Hospital, Baltimore, Maryland, USA

The objective of this study was to compare functional (tumor enhancement and ADC value) and metabolic (Choline concentration) findings in patients with unresectable hepatic tumors treated with TACE. MR Imaging studies were obtained before and after a single TACE treatment in 19 patients with primary or metastatic liver lesions. All targeted tumors had complete loss of the Choline peak, a significant increase in tumor ADC value, and a significant decrease in tumor arterial and venous enhancement, without change in tumor size. These functional findings precede tumor regression in size, and may be utilized to detect early therapeutic response.

14:00 3740. Characterization of Gastric Cancer with Diffusion-Weighted MR Imaging: Prospective Study in 101 Patients Xiao Peng Zhang1, Lei Tang1, Ying Shi Sun1, Kun Cao1, Jie Li1, Ning Wang1 1Beijing Cancer Hospital & Peking University School of Oncology, Beijing, People's Republic of China

MRI examinations were performed on 101 patients with gastric cancer. Diffusion-weighted single-shot echo-planar sequences were performed combined with sensitivity encoding technique. Forty-four gastric cancers displayed uniformly high signal; and 46 displayed nonuniform signal on DWI. Ten Borrmann-4 gastric cancers displayed ¡ sandwich¡± sign on DWI, which appeared high signal on mucosa and serosa layers, with a low signal band mediately which indicate muscularis propria. The ADCs of diffuse-type gastric cancers were lower than that of confining-type with statistical significances.

14:30 3741. Hepatocellular Carcinoma: Assessment of Tumor Oxygenation with BOLD MRI Mohit Naik1, Lorenzo Mannelli1, Hersh Chandarana1, Vivian Lee1, Bachir Taouli1 1NYU Medical Center, New York, New York, USA

In this study we prospectively evaluated the ability of BOLD MRI to assess tumor hypoxia for treated and untreated hepatocellular carcinoma (HCC). Untreated HCC demonstrates significantly higher oxygen uptake (ÄR2*) compared to HCCs post transarterial chemoembolization (TACE) and liver parenchyma. These preliminary results demonstrate the potential utility of BOLD in quantifying tumor hypoxia and evaluating patients prior to and following therapy with TACE.

15:00 3742. Detection of Focal Malignant Liver Lesions: Comparison of T2-Weighted and Diffusion-Weighted Imaging at 1.5T or 3.0T Hua Wang1, Xiaoying Wang, Xuexiang Jiang 1Tianjin Medical University Cancer Institute and Hospital, Tianjin, People's Republic of China

Thirty-three consecutive patients with focal malignant liver lesions on MR images were included in the study. Among them, nineteen patients were examined at 1.5T and 14 patients at 3.0T. Both T2W and DW imaging were performed on each patient. Two observers interpreted images independently and separately. The signal intensity (SI) of tumors and liver were measured at workstation. The ratio of SI of tumor/liver was calculated on tumors more than 1 cm in diameter and without interference of artifacts. There were no significant differences between the performance of 1.5T and 3T. T2W and DW imaging was similar in detection of focal malignant liver lesions. Combined with T2WI, the detection rate on DWI can be improved.

Perfusion of the Liver & Pancreas Hall D Wednesday 13:30-15:30

13:30 3743. Geometry and Flow in the Portal Vein of Normal Subjects and Patients Using Magnetic Resonance Imaging Stephanie M. George1, Puneet Sharma2, Diego R. Martin2, Don P. Giddens1 1Georgia Institute of Technology and Emory University, Atlanta, USA; 2Emory University School of Medicine, Atlanta, USA

Cirrhosis is a leading cause of death in the United States. Previous studies, using ultrasound, have shown varying differences in portal flow in cirrhosis as compared to normal subjects. However, the flow was significantly affected by the degree of cirrhosis. This study evaluates the use of PC-MRI to characterize normal and patient portal hemodynamics as a first step towards non-invasive classification and monitoring of cirrhosis in patients with chronic liver disease. Image post- processing was performed using MATLAB programs to segment the vessel and acquire the velocity values. Preliminary results show the feasibility of PC-MRI determination of detailed normal portal vein hemodynamics with future work to include more subjects and subject-specific modeling.

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14:00 3744. MR Evaluation of Portal Hypertensive Collateral Shunting Vessels for Prediction of Outcomes After Transjugular Intrahepatic Portosystemic Shunt Takeshi Yoshikawa1, 2, Donald G. Mitchell2, David Eschelman2 1Kobe University Graduate School of Medicine, Kobe, Japan; 2Thomas Jefferson University, Philadelphia, Pennsylvania, USA

TIPS is an interventional radiologic minimal invasive procedures and leads to portal decompression. However, selection of patients is still a controversial issue. In addition, various complications after TIPS, such as shunt dysfunction, onset or worsening of hepatic encephalopathy can worsen patientsf QOL. Also, technical difficulty in TIPS procedure differs from patient to patient. We found that patients with pre-existing large portosystemic shunt showed the trends toward higher initial technical failure and tract stenosis rates, and toward lower onset or worsening rates of hepatic encephalopathy. Our results suggest gadolinium-enhanced MRI has the potential to predict therapeutic effectiveness and complications after TIPS.

14:30 3745. Contrast-Enhanced MR Angiography at 3 Tesla for the Assessment of Vascular Complications of Pancreas Transplantation Ahmed Mohamed Housseini1, 2, Ugur Bozlar1, 3, Patrick T. Norton1, Timothy M. Schmitt1, Kenneth L. Brayman1, Hugo Bonatti1, Jaime F. Mata1, Thomas Huerta4, Timothy L. Pruett1, Klaus D. Hagspiel1 1University of Virginia Health System, Charlottesville, USA; 2Suez Canal University, Ismailia, Egypt; 3Gulhane Military Medical Academy, Ankara, Turkey; 4University of Virginia Health System, Charlottesville, Virginia , USA

The role of ceMRA at 3Tesla in the assessment of the pancreas allograft vascular system is currently unknown. 10 ceMRA studies in 8 patients with recent transplant dysfunction were analyzed. All exams were diagnostic and signs suggestive of rejection, infarction or major vascular complications were detected in all cases. MRA findings were concurrent with the final clinical diagnosis in all cases. All 22 arterial segments with angiographic correlation showed complete concordance between MRA and DSA. 3T ceMRA of pancreas allografts is accurate in the depiction of the vascular anatomy and can be used to reliably identify clinically relevant vascular complications.

15:00 3746. Role of MR(A) in Assessment of Pancreas Transplant Complications Taiyo Shimizu1, Lien Tran1, Daniel Margolis1, Steven Raman1, Nagesh Ragavendra1, David Lu1 1David Geffen School of Medicine at UCLA, Los Angeles, California , USA

Pancreas transplant offers life-changing treatment to patients with diabetes mellitus. Despite the improvements in surgical techniques and medical management, complications are not infrequently encountered. The role of MR imaging in assessment of these patients have not been clearly established. Here, we retrospectively reviewed 191 patients who underwent pancreas transplantation. We found that, while US and CT served as the primary imaging modalities, MR(A) often yielded important information which led to clinical interventions in those that underwent them. Thus, the present study suggests MR(A) to be a relatively safe and useful mode of study in assessing post-operative complications of pancreas transplantation.

Female Pelvis & Fetal Imaging Hall D Wednesday 13:30-15:30

13:30 3747. Effect of the Anticholinergic Agent in the Uterus: Size and Signal Change in the Uterine Zonal Anatomy in Fast Spin-Echo T2-Weighted Images Koji Fujimoto1, Asako Nakai1, Tomohisa Okada1, Takashi Koyama2, Kaori Togashi1 1Graduate School of Medicine, Kyoto University, Kyoto, Japan; 2Kyoto University Hospital, Kyoto, Japan

The purpose of this study was to evaluate the effect of the anticholinergic agent on T2-weighted images of the uterus by comparing images before and after the administration of the drug. The area and signal intensity of the inner, outer layer of the uterine corporeal myometrium and the endometrium were measured and evaluated. In addition to suppression of artifacts by intestinal motion, the anticholinergic agent suppressed uterine myometrial contractility and resulted in significant increase in area and signal intensity of the outer layer of the myometrium. CNR between the inner and outer layer of the myometrium was also increased significantly.

14:00 3748. MRI of Perturbed Decidual Angiogenesis - A Characteristic of an Embryo Implantation Failure Associated with the Conditional Depletion of Uterine Dendritic Cells Vicki Plaks1, Tal Birnberg1, Tamara Berkutzki1, Vyacheslav Kalchenko1, Gil Mor2, Nava Dekel1, Steffen Jung1, Michal Neeman1 1Weizmann Institute of Science, Rehovot, Israel; 2Yale University School of Medicine, New Haven, USA

The fate of mammalian embryos is frequently decided at implantation, which is a major limiting step in spontaneous and assisted pregnancies. Angiogenesis is a prerequisite for uterine receptivity, as the endometrium transforms into the decidua. MRI was used to evaluate implantation failure caused by depletion of uterine dendritic cells (uDC) in transgenic mice. 3D-MRI using biotin-BSA-GdDTPA revealed that uDC- depleted uteri exhibited impaired decidual angiogenesis characterized by decreased blood volume and increased vascular permeability, opposing the trends of these parameters in normal implantation. Along with other data, this study suggests a novel non-immune role for uDC in tissue remodeling.

14:30 3749. Diffusion-Weighted MRI (DWI) in Ovarian Masses: Value of DWI Compared to T2 and T1-Weighted MRI and Histopathological Findings Nathalie Hottat1, Thierry Metens1, Martin Kavec1, Celso Matos1 1Erasme Hospital, Brussels, Belgium

The aim of this study is to determine the accuracy of diffusion weighted (DW) imaging in the characterization of ovarian lesions in patients undergoing pelvic MRI. 26 women underwent conventional MR T2-weighted, T1-weighted and DW imaging. All patients underwent surgical excision and MR results were compared to histopathological diagnosis. Combining DW and conventional MR images increased the specificity for the characterization of ovarian masses from 81 to 85%. Colored-ADC map of the lesions and dedicated histogram could be a useful tool in the evaluation of heterogeneous ovarian epithelial tumors.

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15:00 3750. Whole Body Post-Mortem Fetal Magnetic Imaging at 9.4T: A Rapid and Less Invasive Autopsy for Small Foetuses Sudhin Thayyil1, Jon Cleary2, Anthony N. Price2, Rod Jones1, Neil Sebire3, Nikki Robertson4, Mark F. Lythgoe2, Andrew Taylor1 1UCL Institute of Child Health, London, UK; 2UCL Institute of Child Health and Department of Medicine, London, UK; 3Great Ormond Street Hospital NHS Trust, London, UK; 4UCL Institute of Womens Health, London, UK

We describe the first experience of whole body human fetal imaging at 9.4T MRI. 9.4T imaging provided excellent tissue contrast, compared to 1.5T imaging in these fetuses

Breast MRI Hall D Wednesday 13:30-15:30

13:30 3751. Dynamic Contrast Enhanced MRI of the Breast: Kinetic Curve Analysis to Determine the Optimal Temporal Resolution Riham Hossam El-Din El-Khouli1, Michael Jacobs2, Juan Wei2, Peter B. Barker2, Katarzyna J. Macura2, David A. Bluemke2 1Johns Hopkins University, School of Medicine, Baltimore, USA; 2Johns Hopkins University.School of Medicine, Baltimore, USA

Our study aimed to determine the optimal temporal resolution to be used in Dynamuic Contrast EnhancedMRI of the breast. We used a data set of dynamic contrast enhanced MRI with temporal resolution 15 sec per acquisition and then we changed temporal resolution.

14:00 3752. Association of Computer-Based Quantitative Diagnostic Features for CAD with Tumor Phenotype Evaluated by BI-RADS Descriptors Ke Nie1, Jeon-Hor Chen1, Shadfar Bahri1, Orhan Nalcioglu1, Min-Ying Su1 1University of California, Irvine, Irvine, California , USA

Computer-based quantitative features are needed for development of CAD (computer-aided diagnosis) systems. For these features to be accepted, the link with the well-established BI-RADS descriptors needs to be established. In this study we analyzed the quantitative features selected from a database of 43 malignant and 28 benign lesions. The association of 3 features, Compactness, Gray Level Entropy, and Gray Level Sum Average, with lesion phenotypes was investigated. Shape and margin can both contribute to the compactness index. GLCM entropy is associated with homogeneous/heterogeneous enhancements. The gray level sum average is associated with the degree of enhancements.

14:30 3753. Age- And Race- Dependence of the Percent Fibroglandular Breast Density Evaluated by MRI Ke Nie1, Ivy Chau2, Siwa Chan2, Tiffany Tseng1, Jeon-Hor Chen1, H-M Baek1, Orhan Nalcioglu1, Min-Ying Su1 1University of California, Irvine, Irvine, California , USA; 2China Medical University Hospital, Taichung 404, Taiwan

A method was developed to measure the percent fibroglandular breast density, and applied to analyze the age- and race-dependence in 168 women. The percent fibroglandular density was 15.5¡À7.0% for women <45 yo; 13.7¡À6.1% for 45-55 yo; and decreased to 8¡À3.7% for women >55 yo (p < 0.0001). For race-dependence, the Asian have the highest density 14.9¡À8.1%, and the lowest 10.1%¡À6% in White (p = 0.05). For women younger than 45, there was no apparent race-dependence. This method may be applied to measure subtle changes in density, for a woman to evaluate her benefits or risks when considering chemoprevention or hormonal replacement therapy.

15:00 3754. Using Two-Dimensional Magnetic Resonance Spectroscopy in Breast Cancer Detection:Comparing 3.0T Versus 1.5T Xiaoyu Liu1, Scott Lipnick1, Nanette Debruhl1, Roslynn Mcgill1, M A. Thomas1 1UCLA Medical School, Los Angeles, California , USA

Magnetic Resonance Spectroscopy (MRS) allows noninvasive measurements of the concentrations of metabolites in human organs such as breast. Two-dimensional (2D) MRS has better resolution than one-dimensional (1D) MRS by adding a second dimension to each spectrum and has previously been used in breast cancer detection. Recent studies using MRS for human breast cancer detection are limited to 1.5T magnetic fields. The purpose of this study is to compare the spectral resolution and accuracy for breast cancer detection of volume-localized 2D correlated spectroscopy (L-COSY) MRS technique at 1.5T versus 3.0T for detecting breast metabolites.

13:30 3755. Comparison of Choline Concentration and Water-To-Fat Ratio as Biomarkers for Discrimination of Mass/Non-Mass Malignant and Benign Breast Lesions Sunitha B. Thakur1, Lia Bartella, Nicole Ishill, Laura Liberman, Elizabath A. Morris, David D. Dershaw, Jason A. Koutcher1, Wei Huang1 1Memorial Sloan Kettering Cancer Center, New York, New York, USA

This study was undertaken to compare capabilities of absolute Cho concentration [Cho] and W/F ratio in differentiating mass and non-mass malignant breast lesions from benign lesions. Though both [Cho] and W/F ratio are useful diagnostic biomarkers, this study suggest that [Cho] is significantly better than W/F ratio in differentiating malignant lesions, mass and non-mass, from benign lesions, with higher sensitivity and specificity. There is no significant difference in either [Cho] or W/F ratio between mass and non-mass malignant lesions. Incorporation of [Cho] measurement into clinical breast MRI protocol may reduce the number of possibly unnecessary (benign) biopsies in the future.

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14:00 3756. Can We Distinguish Breast Cancer from Mimicking Lesions Using Combined Evaluation with Proton MR Spectroscopy and Dynamic-Contrast -Enhanced MRI? Motoyuki Katayama1, Takayuki Masui1, Kimihiko Sato1, Hiroki Ikuma1, Hidekazu Seo1, Akihiko Kutsuna1, Haruyuki Fukuchi2, Kenji Asano2 1Seirei Hamamatsu General Hospital, Hamamatsu, Japan; 2GE Yokogawa Medical Systems. Ltd, Hino, Japan

We evaluate breast tumor with combined evaluation of time signal intensity curves from dynamic MRI and existence or absence of a choline peak on 1H-MRS in our routine clinical settings. Although time signal intensity curves with dynamic contrast enhanced MR imaging and existence of a choline peak on 1H-MRS was aids for diagnosis of breast malignancies, there were some cases of overlaps and technical failure.

14:30 3757. Fluctuation of Contralateral Normal Breast Enhancement in DCE-MRI of Breast Cancer Patients Undergoing Chemotherapy Hon Yu1, Jack Hsu1, Ke Nie1, Muqing Lin1, Siwa Chan2, Jeon-Hor Chen2, Rita S. Mehta1, Orhan Nalcioglu1, Min-Ying Su1 1University of California, Irvine, California , USA; 2China Medical University Hospital, Taichung, Taiwan

The fluctuation of contrast enhancements in the fibroglandular tissue of the contralateral normal breast of 34 patients undergoing neoadjuvant chemotherapy was investigated. Each patient had at least 3 MRIs, and the variation was calculated. To avoid ROI selection bias, a computer-based segmentation method was applied to segment the entire fibroglandular tissue in the normal breast, and a volume-averaged enhancement time course was measured. The results indicated that post-menopausal women had a lower fibroglandular enhancement in the normal breast, also a lower variation over time, possibly indicating less fluctuation coming from the influence of menstrual cycle.

15:00 3758. Changes of Lesion Morphology and Texture During Neoadjuvant Chemotherapy in Breast Cancer Ke Nie1, Jeon-Hor Chen1, Hon J. Yu1, Shadfar Bahri1, Rita S. Mehta2, Orhan Nalcioglu1, Min-Ying Su1 1University of California, Irvine, Irvine, California , USA; 2Unversity of California, Irvine, California , USA

The change of morphology and texture features of 38 breast cancers receiving AC+taxane neoadjuvant chemotherapy was investigated. Depending on the response to the first line AC and the final pathological finding, the cancers were separated into 4 groups: AC_R (with final CR and PR), and AC_NR (with final CR and PR). Homogeneity index showed a consistent decrease with treatment in the AC_R group, and no significant change in the NR group. The computer extracted information representing lesion morphology and texture changes may have potential to be built into a response prediction model to achieve a high accuracy.

13:30 3759. Assessment of Early Therapeutic Response in Locally Advanced Breast Cancer Using ADC, Volume and Diameter N R. Jagannathan1, Uma Sharma1, K A. Danishad1, V Seenu1 1All India Institute of Medical Sciences, New Delhi, India

Comparison of changes in apparent diffusion coefficient (ADC), volume and diameter in patients with locally advanced breast cancer after I, II and III NACT revealed statistically significant increase in ADC after I NACT compared to pre-therapy value in clinical responders (R) compared to non-responders (NR). The changes in diameter and volume were evident only after II NACT. This suggests the ability of ADC in differentiating NR from R at an early stage of therapy. The sensitivity to detect responder is high for volume and diameter but specificity was 100%, 50% and 70% for ADC, volume and diameter, respectively.

14:00 3760. Efficacy of Lesion Detection Using Diffusion-Weighted Breast Imaging: Comparison of a STIR DWI (DWIBS) and a Convetional DWI Sequence Andreas Stadlbauer1, Reinhard Bernt2, Wilma van der Riet3, Stephan Gruber4, Jürgen Haller2, Erich Salomonowitz1 1Landesklinikum St.Poelten, St. Poelten, Austria; 2Hanusch Krankenhaus, Vienna, Austria; 3European MRI Consultancy (EMRIC), Strasbourg, France; 4Medical University Vienna, Vienna, Austria

To evaluate the efficacy of a diffusion-weighted STIR (DWBIS) and a conventional fat-suppressed diffusion-weighted imaging (cDWI) sequence for detection of breast lesions. 33 patients with a suspected breast lesion underwent both sequences. ADC and eADC values of the lesions between all b-value combinations were calculated. Qualitative evaluation of lesion detectability and conspicuity with DWBIS and cDWI was performed. Conspicuity of tumors and fibroadenmas was better for DWIBS compared to cDWI. We found significant differences between tumors and fibroadenomas for ADC[b0,b1], ADC[b0,b2], eADC[b0,b1], eADC[b0,b2] of DWIBS and cDWI. DWIBS is superior to cDWI in visualization of malign and benign lesions.

14:30 3761. Qualitative and Quantitative Diffusion-Weighted Imaging of Breast Lesions at 3T Gladys Lo1, Victor Ai1, John Chan1, Philip Ng1, Polly Cheung1, KW Li1, Ting Ting Wong1, M Ma1, Raymond Lee1, Daisy Chien2 1Hong Kong Sanatorium, Hong Kong, People's Republic of China; 2UCLA, Los Angeles, California , USA

This is the first clinical study evaluating the value of qualitative versus quantitative diffusion imaging of breast lesions in patients at 3T. Using histologic validations, we determined the sensitivity, specificity, and diagnostic accuracy of qualitative diffusion weighted imaging, quantitative ADC measurement and dynamic contrast-enhanced MRI. We found qualitative diffusion weighted imaging to be highly sensitive in detecting breast lesions while quantitative ADC measurement further increases the specificity to over 90%.

15:00 3762. MRI-Guided Breast Biopsy at 3T Using a Dedicated Large Core Biopsy Set; Feasibility and Initial Results Ritse M. Mann1, Jeroen Veltman1, Axel Winkel2, Carla Boetes1 1Radboud University Nijmegen Medical Center, Nijmegen, Netherlands; 2INVIVO Germany GMBH, Schwerin, Germany

This study evaluated the use of a dedicated MR-guided breast biopsy set for intervention at 3T. Due to the use of plastic coaxial needles, needle placement can be accurately assessed. The procedure is technically as easy as biopsy at 1.5T and the diagnostic yield is at least equal to biopsy at 1.5T. Therefore, this set allows biopsy of 3T only visible lesions or the performance of biopsy in conjunction with other techniques that benefit from higher field strength.

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13:30 3763. Quantitative Morphology and Texture Analysis of Breast Parenchymal Pattern Ke Nie1, Jeon-Hor Chen1, Siwa Chan2, Orhan Nalcioglu1, Min-Ying Su1 1University of California, Irvine, Irvine, California , USA; 2China Medical University Hospital, Taichung 404, Taiwan

Quantitative texture and morphology analysis was applied to evaluate different breast parenchymal patterns. 43 cases with distinctly different patterns (I: mostly fatty, II: intermingled fat and fibroglandular tissue, III: fibroglandular tissue inside surrounded by fat outside) were identified. The GLCM and LAWS¡¯ texture features could differentiate between Type-I from Type-II and III, but not between Type-II and III. The morphology features of the segmented fibroglandular tissue, particularly the compactness ¡ the ratio of perimeter to area¡± could differentiate between them despite of their similar percent density. The method may be applied to evaluate the association of parenchymal pattern with cancer risk.

14:00 3764. Efficacy of MRI Morphology and Kinetic Parameters in Distinguishing Benign and Malignant Breast Lesion Tie qiao Du1, bao zhi Ding1, chun yu Sang1, chao zhang1 1Fuxing Hospital Affiliated to Capital University of Medicine Sciences, Beijing, People's Republic of China

Objective: To discuss a effect of combined morphology and kinetic data of MRI in distinguishing malignant tumors from benign lesions of breast. Methods: A CE-MRI study was performed on 17 patients with benign lesion and 16 cases with malignant tumors. Results and conclusion: Marginal feature, shape, spreading signs,time-signal intensity curve, and signal enhanced rate between the benign and malignant group represented significant difference, respectively. Sensitivity, specificity,and accuracy combined with former 5 indicators were 93.8%,88.2%and 90.9%, respectively. The scoring method of breast could help to differentiate malignant from benign lesions.

14:30 3765. Heart Saturation for Bilateral Breast MRI: Reduction of Cardiac Motion Artifacts Rebecca Rakow-Penner1, Brian Hargraeves1, Laura Pisani1, Bruce Daniel1, Gary H. Glover1 1Stanford University, Stanford, California , USA

Cardiac motion causes significant artifact in breast MRI. By applying a cylindrical saturation encompassing the heart, heart motion artifact is reduced. The heart saturation pulse is a 2D spiral excitation in both x and y, followed by crushers. This pulse precedes a spectral spatial bilateral breast acquisition sequence. The sequence was tested on healthy volunteers and a patient with contrast. Significant artifact reduction is noted.

15:00 3766. Fat Saturation and Motion Compensation Using Gating and Reordering Peter Siegler1, Claire Holloway1, Petrina Causer1, Donald Bruce Plewes1 1Sunnybrook Health Sciences Centre, Toronto, Canada

Dynamic contrast enhanced breast MRI is a sensitive technique for the detection of breast cancer. Therefore, to aid breast conserving surgeries, MR breast imaging with supine positioning of the patient was implemented to match the breast configuration in the operating room. Since respiratory motion is not negligible in supine breast MRI, time consuming motion compensation is essential. Conventional fat-suppression would further prolong acquisition, resulting in unacceptably long scan times. Here, a method of partially reordered fat saturation combined with k-space reordering and gating for motion-compensation is presented which allows fast motion-compensated, fat-suppressed, supine breast MRI with minimal increases in scan-time.

13:30 3767. Rapid Acquisition of High Resolution 3D T2-Weighted Water-Silicone Separated Breast Images Ananth J. Madhuranthakam1, Martin P. Smith2, 3, Reed F. Busse4, Huanzhou Yu5, Ann Shimakawa5, Anja C. Brau5, Philip J. Beatty5, Scott B. Reeder6, Neil M. Rofsky2, 3, Jean H. Brittain4, Charles A. McKenzie7 1GE Healthcare, Boston, Massachusetts, USA; 2Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA; 3Harvard Medical School, Boston, Massachusetts, USA; 4GE Healthcare, Madison, Wisconsin, USA; 5GE Healthcare, Menlo Park, California , USA; 6University of Wisconsin-Madison, Madison, Wisconsin, USA; 7University of Western Ontario, London, Canada

We demonstrate the rapid acquisition of high-resolution 3D T2-weighted water and silicone separated images of the breast to visualize possible silicone ruptures. The technique combines the IDEAL (Iterative Decomposition of water and fat with Echo Asymmetry and Least squares estimation) chemical-shift imaging method modified to separate water and silicone with 3D-FSE-Cube that uses an eXtended Echo Train Acquisition (XETA) and 2D partially parallel imaging. An adiabatic chemically selective inversion pulse is used to suppress the fat. Uniform separation of water and silicone with high near-isotropic resolution in all three dimensions is achieved in 11.5 minutes of scan time.

14:00 3768. Modified ZMART for Supine Breast MRI Peter Siegler1, Claire Holloway1, Petrina Causer1, Donald Bruce Plewes1 1Sunnybrook Health Sciences Centre, Toronto, Canada

Dynamic contrast enhanced MRI shows a high sensitivity for breast cancer. Therefore, to allow aid of breast conserving surgeries, MR breast imaging with supine positioning of the patient was implemented to match the later situation in the operating room. The zonal motion-adapted acquisition and reordering technique (ZMART) was used to compensate for respiratory motion. However, if the respiration pattern during the scan changes, the reordering is modified in order to minimize scan-time, resulting in slightly corrupted reordering results. Here a modified ZMART is proposed, which keeps the reordering scheme constant by allowing a small increase in scan-time.

14:30 3769. Morphologic and Dynamic Differences Between Invasive Ductal and Invasive Lobular Carcinomas of the Breast Ritse M. Mann1, Henkjan Huisman1, Jeroen Veltman1, Mark Stoutjesdijk1, 2, Carla Boetes1 1Radboud University Nijmegen Medical Center, Nijmegen, Netherlands; 2Ikazia Hospital, Rotterdam, Netherlands

This study evaluated differences between invasive lobular carcinomas (ILC)and invasive ductal carcinomas (IDC)of the breast with respect to morphology and enhancement patterns. Apperently, there are no significant differences in morphology, nor in thye most malignant looking voxels, however distribution of kinetic enhancement profiles is significantly different between ILC and IDC.

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15:00 3770. Improvement of Fat Suppression in Breast Imaging Shinichi Kitane1, Mitsue Miyazaki2, 3, Erin Kelly1, 1, Aida Doubrava, 14 1; 2Toshiba Medical Research Institute USA, Vernon Hills, USA; 3Toshiba Medical Systems Corp., Otawara, Japan; 4Rad. LTD, Tucson, Arizona , USA

Breast imaging suffers from B0 and B1 problems due to strong susceptibility effects caused by shapes of breasts and inhomogeneity of coils. Dynamic study using segmented 3D FFE type sequences requires high resolution and good temporal resolution and also demands good fat suppression for diagnostics. Therefore, a short inversion SPIR technique is normally used in dynamic sequences to minimize the inversion time (TI) to reduce the scan time. In this study, we have applied a double fat suppression technique, comprising a spectral-selective SPIR and a CHESS pulses, in 3D dynamic sequence and compared with the regular SPIR 3D dynamic technique.

13:30 3771. Artifact Size Caused by Breast Tissue Marking Clips at 1.5T and 3T MRI: A Phantom Study Qi Peng1, Carol Dornbluth1, Kenneth A. Kist1, Anqi Zhou1, Pamela M. Otto1 1UT Health Science Center at San Antonio, San Antonio, Texas, USA

3T MRI introduces larger signal void size artifact surrounding metallic breast marking clips than at 1.5T. In this study we compare the signal void artifact size at both 1.5T and 3T and to test the impact of field strength, different readout bandwidth, and TE. At the tested spatial resolution (1×1×2mm3) using a 3D GRE sequence, the artifact sizes at 3T are only 10-20% larger than those of 1.5T. Increasing readout bandwidth didn’t reduce the artifact size, and reducing TE slightly reduced the artifact size. Therefore, 3T scanners can be used to detect and follow-up breast cancer adjacent to metallic tissue marking clips if short TE and high spatial resolution are used.

14:00 3772. Withdrawn

14:30 3773. Segmentation of DCE Breast MRI Masses: Pilot Observer Study Lina Arbash Meinel1, Thomas Buelow2, Martin Bergtholdt, Ursula Kose3, Akiko Shimauchi4, Gillian Newstead4

In this study, we investigated quantitative measures of breast tissue patterns using Magnetic Resonance Imaging (MRI). High breast density is a strong marker for breast cancer risk and mammography is currently the approved modality to obtain quantitative breast density assessment. However mammography performs poorly for high-density populations. MRI provides very good soft-tissue contrast and tridimensional information on breast tissue content. We showed that women with similar mammographic breast densities may present very different breast tissue patterns on MRI. We defined new quantitative measures using breast MRI data of 50 normal volunteers and showed that the new MR breast tissue pattern index may provide complementary information to MR breast density. We believe that our new MRI quantitative measures could have applicability to help improve breast cancer risk assessment techniques. PURPOSE: A pilot study was performed in preparation for a future clinical study. METHOD: Two observers traced the borders of 11 masses and placed a seed pixel in three sessions to measure inter-and intra-observer variation. The segmentations were compared pair-wise to evaluate similarity.RESULTS: The observed inter- and intra-observer variation was similar. The robust seed-point placement was significantly more reproducible than either manual contouring or directly placed seed-points. The percent overlap between computer and manual is not significantly different from the two manual readings.CONCLUSION: The computerized segmentation with robust seed-point selection is more reproducible and reliable than manual methods. 1Philips Research of North America, Chicago, Illinois, USA; 2Philips Research Hamburg, Hamburg, Germany; 3Philips Medical Systems, Netherlands; 4University of Chicago, Chicago, Illinois, USA

15:00 3774. The Clinical Value of Three-Dimensional (3D) Dynamic MR Imaging for the Bilateral Breasts: is It Worth Performing for Patients with Microcalcifications on Mammography? Ayano Akita1, Akihiro Tanimoto1, Shigeo Okuda1, Hiromitsu Jinno2, Michiko Nemoto2, Sachio Kuribayashi1 1Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Japan; 2Keio University School of Medicine, Japan

Three-dimensional dynamic MRI for the bilateral breasts was performed prior to stereotactic vacuum-assisted breast biopsy (SVAB) to evaluate whether the MRI findings can help to predict the presence of malignancy. We devised five categories for MRI findings according to BI-RADS. Assuming that the category 4 and 5 were malignant, mammography had a sensitivity of 50%, a specificity of 86%, and an overall accuracy of 78%, whereas MRI had a sensitivity of 88%, a specificity of 100%, and an overall accuracy of 97%. This method may alter the application of SVAB, with better diagnostic value than mammography alone.

Lung MRI Hall D Thursday 13:30-15:30

13:30 3775. Dynamic Accelerated 3He MRI of Human Lungs with a 128-Element Receive Coil Array at 3T Davide Santoro1, Vinay Pai1, Abram Voorhees2, Ray Lee1, Bernd Stoeckel3, Niels Oesingmann3, Jean Reid1, Glyn Johnson1, Daniel Sodickson1 1New York University School of Medicine, New York, USA; 2Siemens Medical Solutions, Inc., Malvern, USA; 3Siemens Medical Solutions, Inc., New York, USA

A set of dynamic 3He images have been acquired with a new 128 channel receiver system and custom-designed 128-element coil array. This technology will ultimately allow high degrees of acceleration that will lead to dramatic improvements in temporal resolution for 3He MRI with possible applications to flow imaging under fast expiration

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14:00 3776. Lung Volume and Motion Measured by Dynamic 3D MRI Using a 128-Channel Receiver Coil Junichi Tokuda1, 2, Melanie Schmitt, 23, Yanping Sun1, 2, Yi Tang1, 2, Samuel Patz1, 2, Carolyn E. Mountford1, 2, Nobuhiko Hata1, 2, Lawrence L. Wald, 23, Hiroto Hatabu1, 2 1Brigham and Women's Hospital, Boston, Massachusetts, USA; 2Harvard Medical School, Boston, Massachusetts, USA; 3Massachusetts General Hospital, Boston, Massachusetts, USA

The feasibility to use a state-of-the-art 3T MRI scanner equipped with a 128-channel coil for the imaging of the free-breathing lung was evaluated. Recent developments in dynamic 3D MRI have enabled physiological study of the lung in a dynamic state, but image quality has limited the accomplishment of automated segmentation. In this study, 3D lung images were acquired from two healthy volunteers every 1.3-1.6 s during free breathing. The images provide sufficient contrast for the observation of chest wall and diaphragm motion as well as the measurement of lung volume and motion based on the automated segmentation.

14:30 3777. Quantitative Analysis of Asynchronous Motions in Human Pulmonary Parenchyma Via Non-Rigid Registration Masaya Takahashi1, Shigeto Kubo1, Tessa A. Sundaram2, Shigeru Kiryu1, James C. Gee2, Hiroto Hatabu3 1Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA; 2University of Pennsylvania, Philadelphia, Pennsylvania, USA; 3Brigham and Women's Hospital, Boston, Massachusetts, USA

The paradoxical motions in thoracoabnominal motions and/or right and left hemidiaphragmatic motions are observed in patients with pulmonary disorders such as emphysema. The quantification of these asynchronous respiratory motions could be a diagnostic method to evaluate the progression of emphysema. In this study, we applied the method to quantify the asynchrony in the right and left parenchymal motion and compared with those in the hemidiaphragmatic motions.

15:00 3778. Influence of Distribution of Emphysema on Diaphragmatic Motion in COPD Patients Tae Iwasawa1, Hiroshi Takahashi, Takashi Ogura, Toshiyuki Gotoh, Seiichiro Kagei, Junichi Nishimura1, Tomio Inoue 1Kanagawa Cardiovascular & Respiratory Center, Yokohama, Japan

We compared CT and MR of 34 chronic obstructive lung disease (COPD) patients to evaluate the influence of the distribution of the emphysema on the paradoxical diaphragmatic movement (Mp(%)). Average of Mp(%) on MR was 11.9}3.9 (%). It showed significant correlation with forced expiratory volume in 1 second (p=0.04). RA-950 (relative lung volume under -950HU) of lower lung part on CT showed significant correlation with Mp(%) (p<0.001). RA-950 of upper lung fields showed no significant correlation with Mp(%). Our results suggest that emphysema of the lower lung would have greater influence on the diaphragmatic motion than the upper lung emphysema.

13:30 3779. Detection of Reperfused Pulmonary Arteriovenous Malformations with Contrast-Enhanced Magnetic Resonance Angiography Alexander Massmann1, Armin Opitz1, Marcus Katoh1, Urban W. Geisthoff2, Arno Buecker1, Guenther K. Schneider1 1Saarland University Hospital, Homburg/Saar, Germany; 2Clinics of City Cologne (Holweide), Cologne, Germany

Hereditary hemorrhagic telangiectasia (HHT) also known as Rendu-Osler-Weber disease is an autosomal-dominant inherited vascular disorder associated with mucocutaneous, pulmonary, cerebral and visceral arteriovenous malformations (AVM). Pulmonary arteriovenous shunts (PAVMs) are associated with high morbidity and mortality. The primary choice of treatment of PAVMs is catheter embolization with compact packing of platinum coils, which is technically safe and effective. In contrast to an initial successful occlusion, there may be a reperfusion of embolized feeding vessels or opening of collateral vessels. The study shows that contrast-enhanced magnetic resonance angiography (CE-MRA) is a useful tool for regular follow-up examinations of treated PAVMs.

14:00 3780. Dynamic 3D Contrast-Enhanced Perfusion Imaging of Lung Cancer with One-Second Temporal Resolution Pippa Storey1, Jane P. Ko1, Daisuke Nonaka1, Harvey Pass1, Andrew D. Hardie1, Daniel Moses1, Kellyanne Mcgorty1, Jean Reid1, Jeff L. Zhang1, Ke Zhang1, Qun Chen1 1New York University School of Medicine, New York, New York, USA

Quantitative perfusion imaging of lung cancer has to date been precluded by the low temporal resolution of conventional dynamic contrast-enhanced techniques. By combining a variety of fast imaging methods, such as parallel imaging, partial Fourier sampling and TWIST, we have achieved one-second temporal resolution with 3D coverage of the tumor and high spatial resolution. This allows images to be acquired continuously during free breathing with minimal motion artifacts throughout the baseline, uptake and washout phases of the contrast agent. Application of tracer kinetic models may provide useful information regarding measures of angiogenesis such as tumor vascularity and vessel permeability.

14:30 3781. 3D Quantitative Contrast-Enhanced Perfusion Measurements of the Human Lung Using the Prebolus Approach and Signal Corrections Markus Oechsner1, 2, Christian Oliver Ritter1, Marc Hagemeister1, Peter M. Jakob1, Tobias Wichmann1, Dietbert Hahn1, Meinrad Beer1, Herbert Köstler1 1University of Wuerzburg, Wuerzburg, Germany

Whole lung contrast-enhanced quantification of pulmonary perfusion was performed with different doses using the prebolus approach and with single bolus. The signal curves from all slices were corrected for the sensitivity profile of the array-coil. Corrected perfusion values increased from ventral to dorsal. Without signal correction, higher PBF was found in ventral and dorsal slices. The application of high doses resulted signal saturation in lung parenchyma as well as in the AIF. With the prebolus technique, higher doses can be used to improve the SNR in lung parenchyma.

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15:00 3782. Lung Cancer Perfusion: Hybrid Acquisition Technique for 3D MRI to Overcome Breath Hold Limitations and Minimize Motion-Related Displacement Christian Hintze1, Alto Stemmer2, Michael Bock1, Tristan Kuder1, Frank Risse1, Julien Dinkel1, Michael Puderbach1, Christian Fink3, Hans Ulrich Kauczor1, Jürgen Biederer1, 4 1German Cancer Research Center, Heidelberg, Germany; 2Siemens AG, Erlangen, Germany; 3University Hospital Mannheim, Mannheim, Germany; 4University Hospital Schleswig-Holstein Campus Kiel , Kiel, Germany

To record perfusion of lung cancer by imaging requires examination times exceeding breath hold capabilities of patients. The assessment is further disturbed by overall motion of the thorax. The aim of this MR study was to evaluate a hybrid breath hold and navigator triggered technique in combination with a FLASH 3D in imaging lung tumor perfusion to overcome the motion-related challenges. Contrast-enhanced dynamic 3D MRI perfusion studies with initial high temporal resolution of wash-in and subsequent expiratory triggered coverage of wash-out for a typical combined acquisition time of 4 minutes were successfully performed in lung cancer examinations.

13:30 3783. Oxygen-Enhanced T1- And T2*-Mapping of the Human Lung at 0.2 Tesla Markus Oechsner1, 2, Daniel Stäb1, Eberhard Daniel Pracht1, Johannes F.T. Arnold1, Herbert Köstler1, Dietbert Hahn1, Meinrad Beer1, Peter M. Jakob1 1University of Wuerzburg, Wuerzburg, Germany

The object of this work was the implementation and measurement of oxygen-enhanced T1 and T2* maps for functional lung imaging at 0.2 Tesla. T1 maps were acquired with an IR-Snapshot FLASH sequence. T2* was measured with a multi gradient-echo sequence. Furthermore, a navigator-echo technique was used, to acquire T2* maps during free respiration. A distinct reduction of both relaxation times (T1 ~ 8%; T2* ~ 9%) was found when changing the respiratory gas to 100% oxygen. All measurements were successfully performed during breath-hold or free respiration and are thus applicable for examinations of lung patients.

14:00 3784. Influence to Oxygen-Enhanced MR Imaging: Comparison Between Non-Slice and Slice Selective Types on HASTE Sequence with Adiabatic Inversion Pulse Daisuke Takenaka1, Michael Puderbach2, Yoshiharu Ohno1, Michael Bock2, Frank Risse2, Sebastian Ley2, Hans Ulrich Kauczor, Kazuro Sugimura1 1Kobe University Graduate School of Medicine, Kobe, Japan; 2German Cancer Research Center, Germany

Oxygen-enhanced MR imaging has been reported as one of the pulmonary functional MR imaging, and potential for assessment of ventilation and/ or oxygen-transfer. In the past literature, a few investigators suggested that slice selection type might have influence to oxygen-enhancement within the lung. However no one has clearly described the influence of IR pulse type between slice-selective and non-slice-selective on oxygen-enhanced MR imaging of lung. The purpose of the present study is to demonstrate the influence of slice selection type of oxygen-enhanced MR imaging to oxygen-enhancement within the lung.

14:30 3785. Quantitative MRI Measurement of Lung Density Must Account for the Change in T2* with Lung Inflation Rebecca J. Theilmann1, Tatsuya J. Arai1, Ahsan Samiee1, Susan R. Hopkins1, Richard B. Buxton1, David J. Dubowitz1, Gordon K. Prisk1 1UCSD, La Jolla, California , USA

Because of high magnetic susceptibility effects in the lung, T2* is extremely short and as a result standard GRE imaging of the lung suffers from significant signal loss. For an accurate determination of lung water content one must back-extrapolate the signal from lung to an echo time of 0. To obtain T2* and lung density measurements, a GRE sequence was developed that rapidly acquires multiple single echo acquisitions within a single breath-hold. Results show that T2* increases with decreasing lung volume and increasing lung density.

15:00 3786. Correction of Errors Due to RF Field Inhomogeneities in Hyperpolarized 3He Measurement of Alveolar Oxygen Partial Pressure in Human Lung Alexei V. Ouriadov1, Roya Etemad-Rezai2, Grace Parraga1, Giles Santyr1, 3 1Robarts Research Institute, London, Canada; 2London Health Science Centre, London, Canada; 3University of Western Ontario, London, Canada

Helium MR imaging was used to obtain alveolar oxygen partial pressure map of five healthy volunteers and B1 filed map. Measurements were performed at 3T (GEHC, Excite12.0). It was shown that inhomogeneous RF coils leads to variations in flip angle across the lung which can propagate into pA02 inaccuracy. Results of B1 field corrections for the five human subjects suggest that once found, the B1 field map for the RF coil in the magnet can be used to correct pAO2 maps from any subject in any position, provided that the coil is re-positioned identically in the magnet for each subject.

13:30 3787. Assessing Local Lung Function: Measurement of Regional FEV1/FVC Using Tissue Tracking MRI Ke Zhang1, Abram Voorhees2, Elan Grossman1, Kenneth I. Berger1, Roberta M. Goldring1, Joan Reibman1, Chun Xu3, Larry Dougherty3, Qun Chen1 1New York University, New York, New York, USA; 2Siemens Medical USA, Malvern, Pennsylvania, USA; 3University of Pennsylvania, Philadelphia, Pennsylvania, USA

We have shown the capability of using a real time tissue tracking MRI technique for the quantitative measurement of regional mechanics of the lung. Particularly, we have demonstrated that local FEV1/FVC can be measured on a regional basis, showing marked difference in local lung function between healthy subjects and patients with asthma. Such an assessment of airflow dynamics at the local level may provide a potentially very powerful tool for evaluating the contribution of peripheral airways to obstructive airway disease.

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14:00 3788. Fluorine-19 MRI of the Lung During High Frequency Oscillatory Ventilation (HFOV): Visualization of the Wash-Out of C4F8 Ursula Wolf1, Alexander Scholz1, Matthias David1, Rainer Koebrich2, Maxim Terekhov1, Wolfgang Guenter Schreiber1 1Johannes Gutenberg University, Mainz, Germany; 2Maquet, Germany

In clinical research, diagnostic imaging is the main application field of MRI. With the advent of MRI of contrast gases, not only gas filled spaces within the body can be visualized, but also flow mechanics of these gases within the bronchial tree. During high frequency oscillatory ventilation (HFOV), very small tidal volumes are applied at high frequencies. As HFOV is considered as lung protective, it is used in ARDS patients. To contribute to a better understanding of HFOV, we visualized the wash-out of C4F8 gas during HFOV at two different frequencies in healthy pigs.

14:30 3789. In-Vivo Hyperpolarized 3He Lung Imaging in Mice Using X-Centric FGRE Sequence and Custom-Designed FlexiVent Ventilator Alexei V. Ouriadov1, Richard Kennan2, Deborah Slipetz3, Giles Santyr1, 4, Donald Williams3, Brian K. Rutt1, 4, Richard Hargreaves3, Ben T. Chen2, 3 1Robarts Research Institute, London, Canada; 2Merck Co., Rahway, New Jersey, USA; 3Merck Frosst Ltd., Kirkland, Canada; 4University of Western Ontario, London, Canada

Due to the size of the mouse, the requirements for high image resolution and animal preparations to establish a stable physiological condition and HP 3He gas delivery are very challenging to meet. FGRE sequence has not been widely used for high resolution HP 3He lung imaging in mice as the frequency encoding gradient could cause 3He signal loss in the larger airways due to diffusion. We successfully acquired high-resolution HP 3He lung images in mice using the modified x-centric fGRE sequence to minimize diffusion attenuation. The custom-built flexiVent ventilator provides critical lung function data for image analysis and interpretation.

15:00 3790. An MR-Compatible Active Breathing Control (MR-ABC) Johannes FT Arnold1, 2, Philipp Mörchel1, Eckard Glaser3, Peter M. Jakob1 1University of Würzburg, Würzburg, Germany; 2Research Center for Magnetic Resonance Bavaria (MRB), Würzburg, Germany; 3Viasys Healthcare, Höchberg, Germany

Motion is a major obstacle for cardiac, chest, and abdominal imaging. Several approaches have been proposed to allow for segmented k-space acquisition while avoiding motion artifacts. Most of these methods focus solely on the detection of motion, e.g. navigator techniques or a respiratory belt. Nevertheless, respiratory movement during data acquisition is not prevented with these techniques. To avoid respiratory movement during the data sampling period, an MR-compatible active breathing control (MR-ABC) was developed. The MR-ABC allows for cardiorespiratoy-synchronized MRI while “freezing” the breathing motion. The potential of an MR-ABC device is demonstrated in lung imaging.

Metabolism - Clinical Studies Hall D Thursday 13:30-15:30

13:30 3791. Validation of Fully Automated Segmentation of Visceral Adipose Tissue from Whole-Body Continuously Moving Bed MRI Joel Kullberg1, Lars Johansson1, 2, Håkan Ahlström1, Frederic Courivaud3, Peter Koken4, Holger Eggers4, Peter Börnert4 1Uppsala University, Uppsala, Sweden; 2AstraZeneca R&D, Mölndal, Sweden; 3Philips Medical Systems, Oslo, Norway; 4Philips Research Europe, Hamburg, Germany

A fully automated technique for segmentation of visceral adipose tissue from whole-body reconstructed fat and water image data is presented. Data is acquired using continuously moving table imaging. The segmentation technique is based on commonly used image processing methods. The validation was performed using ten volunteers and manually segmented results were used as reference. The segmentation results are promising. Results can likely be improved further by automated exclusion of bone marrow.

14:00 3792. Reproducibility of Fast Whole-Body Assessment of Adipose Tissue Depots from Continuously Moving Bed MRI Joel Kullberg1, Lars Johansson1, 2, Håkan Ahlström1, Frederic Courivaud3, Peter Koken4, Holger Eggers4, Peter Börnert4 1Uppsala University, Uppsala, Sweden; 2AstraZeneca R&D, Mölndal, Sweden; 3Philips Medical Systems, Oslo, Norway; 4Philips Research Europe, Hamburg, Germany

Method reproducibility studies give information about method precision and variability, which is essential for study group size determinations. Continuously moving bed imaging can be used to rapidly acquire whole-body MRI data allowing assessment of adipose tissue distribution. A recently developed image processing algorithm can be used to extract and separate abdominal visceral and subcutaneous adipose tissue from these whole-body datasets. The reproducibility of this acquisition and post processing has been studied using repeated acquisitions of nine volunteer subjects. Results suggest a substantial value in this type of acquisition and analysis technique allowing obesity related studies of large patient cohorts.

14:30 3793. Lipid Fraction Measurement Incorporating T1 and RF Inhomogeneity Correction Jinghua Wang1, Hyeonjin Kim2, Maolin Qiu2, Robert Todd Constable2 1Yale University , New Haven, Connecticut, USA; 2Yale University, New Haven, Connecticut, USA

The content and distribution of fat in humans has received increased attention in recent years because of its relationship to many diseases including cancer, coronary heart disease, diabetes, and obesity. Quantification of lipid, therefore, is very significant for diagnoses, treatment, and understanding disease processes [1, 2]. At short TR, lipid content measured strongly depends on relaxation times, RF inhomogeneity, and pulse sequences [3, 4]. Here, the lipid fraction in skeletal muscle is accurately estimated by incorporating T1 and RF inhomogeneity corrections.

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15:00 3794. Absolute Quantification of Adipose Tissue Fat Mass by MRI Using a Signal Intensity Based Model Houchun Harry Hu1, Krishna S. Nayak1 1University of Southern California, Los Angeles, California , USA

A quantification scheme is presented to compute adipose tissue fat mass on a voxel-by-voxel basis using MRI. The method utilizes chemical-shift techniques to separate fat and water components. In this work, we demonstrate the quantification using low-flip-angle spoiled-gradient-echo data, such that resultant image signal intensity is approximately a linear function of proton density. Fat mass in several ex vivo swine samples are calculated, where values from MRI are within 5-8% of results obtained from reference lipid chemical assay. We hypothesize that the method potentially represents a non-invasive and accurate approach to measure fat mass in body composition and obesity research.

13:30 3795. Quantification of Pancreatic and Hepatic Fat Using Gradient Echo MRI – Comparison of a Spatial-Spectral Excitation Technique with In/Opposed-Phase Imaging Nina Franziska Schwenzer1, 2, Jürgen Machann1, Petros Martirosian1, Christina Schraml1, Claus D. Claussen1, Fritz Schick1 1University Hospital of Tuebingen, Tuebingen, Germany

Fatty infiltration of pancreas and liver occurs in several metabolic disorders. The most common MRI technique to quantify fat uses in-phase and opposed-phase (IN/OP) images. Unfortunately, this technique is hampered by relaxation effects (T1/T2*).Therefore, goal of the present study was the quantification of pancreatic and hepatic fat using fat-selective spectral-spatial gradient-echo imaging and the comparison of the gained results with an IN/OP method.The results suggest that both methods are valid for pancreatic and hepatic fat quantification. However, spectral-spatial imaging seems to be a more promising approach in clinical routine offering solid values without major T1/T2* corrections.

14:00 3796. Improved Detection of Pancreatic Islets in Vivo Using Double Contrast Vít Herynek1, Zuzana Berková1, Peter Girman1, Frantisek Saudek1, Milan Hájek1 1Institute for Clinical and Experimental Medicine, Prague, Czech Republic

Transplantation of pancreatic islets is an alternative approach to the treatment of type 1 diabetes. Visualization of transplanted islets using MRI requires labeling of islets by a suitable contrast agent. Detection of islets labeled by iron oxide based contrast agents can be significantly improved using intravenous administration of a suitable gadolinium contrast agent prior to MRI.

14:30 3797. Following of the Fate of Transplanted Pancreatic Islets in the Early Post-Transplant Period by MRI. Their Automatic Detection and Quantification Daniel Jirak1, Jan Kriz1, Michal Strzelecki2, David White1, Paula Foster1 1Robarts Research Institute, London, Canada; 2Technical University of Lodz, Lodz, Poland

We present a novel transplantation model and a simple and robust segmentation method, which allow an easy quantification of iron-labeled cells and minimizes subjective evaluation. Our approach was applied to the task of monitoring the fate of transplanted pancreatic islets in diabetic mice during the early post transplant period. MRI analysis shows erratic response to transplanted tissue in the first few days. The effect of acute rejection in the second week caused differences between isograft and allograft Tx to be observed.

15:00 3798. Regional Quantitative DCE-MRI in the Pancreas Josephine Helen Naish1, Charles E. Hutchinson1, Zahra Esmail2, Yvon Watson1, Sue Cheung1, Deirdre M. McGrath1, John C. Waterton1, 3, Paul D. Hockings4, Chris J. Taylor1, Geoff J. Parker1 1University of Manchester, Manchester, UK; 2University of Salford, Salford, UK; 3AstraZeneca, Macclesfield, UK; 4AstraZeneca, Mölndal, Sweden

Functional MRI methods may provide valuable probes of pancreatic islet microvasculature, important in the study and treatment of diabetes mellitus. In this study we demonstrate the feasibility of regional tracer kinetic model based DCE-MRI in healthy volunteers. Sensitivity of the technique is investigated by comparing regions of interest in the head and tail sections of the pancreas. Parameters relating to the blood volume and capillary permeability differ significantly between the head and tail, possibility reflecting structural differences between these regions.

Prostate Cancer Hall D Monday 14:00-16:00

14:00 3799. Prostate Cancer Detection in Patients with Intermediate Prostate Specific Antigen Level Using Combined Trace Apparent Diffusion Coefficient and Nodular Size: Comparison with Transrectal Core Biopsy Yu-Jen Chen1, Yuan-Shiaw Pu, Chia-Ton Shun, Wei-Cyne Chu2, Wen-Yi Isaac Tseng, 3 1Institute of Biomedical Engineering, National Yang-Ming University, Taipei, Taiwan; 2Institution of Biomedical Engineering, National Yang-Ming University, Taipei, Taiwan; 3Center for Optoelectronic Biomedicine, National Taiwan University College of Medicine, Taipei, Taiwan

This is a prospective study using diffusion tensor imaging for detecting prostate cancer in the intermediate risk patients, who have the PSA level of 4~20ng/ml. Comparing with TRUS-biopsy results, the judgments only using tADC showed a high NPV of 99%. It indicates the method can effectively exclude the unnecessary biopsies from this patient group. Combining the criterion of nodular size, the comparison with pathologies showed high corresponding results with accuracy of 97%. This validates the method using combined tADC and nodular size can be an effectual tool in pre-biopsy screening.

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14:30 3800. High Resolution Diffusion Tensor Imaging in Prostate Cancer Yu-Jen Chen1, Woei-Cyne Chu2, Wen-Yi Isaac Tseng, 3 1Institute of Biomedical Engineering, National Yang-Ming University, Taipei, Taiwan; 2Institution of Biomedical Engineering, National Yang-Ming University, Taipei, Taiwan; 3Center for Optoelectronic Biomedicine, National Taiwan University College of Medicine, Taipei, Taiwan

In this study, we used endorectal coils to acquire high resolution, high signal-to-noise (SNR) DTI images on patients who had biopsy proven prostate cancer. The aim of the study was to examine the correlations between tADC and FA values amongst benign and tumor tissues and to assess the feasibility of using high resolution DTI technique in identifying prostate cancer. Our results showed both tADC and FA values were significantly different between tumor and benign tissues. In addition, tADC and FA values exhibit a high negative correlation in cancerous tissues.

15:00 3801. Apparent Diffusion Coefficient as a Prognostic Biomarker in Early Stage Prostate Cancer Nandita M. deSouza1, Veronica A. Morgan, Sophie F. Riches2, Chris Parker1, Nicholas J. vanAs1 1Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Sutton, UK; 2Institute of Cancer Research, Sutton, UK

The challenge of managing localised prostate cancer is to distinguish patients who benefit from radical treatment from those who do not. This study investigates apparent diffusion coefficient (ADC) obtained on diffusion-weighted imaging as a prognostic biomarker in prostate cancer patients managed by active surveillance. On univariate analysis tumor ADC was a significant predictor of adverse repeat biopsy findings (p<0.0001) and time to radical treatment (p<0.0001). Area under ROC curves for ADC was 0.70 for adverse repeat biopsy findings; 0.83 for prediction of radical treatment. ADC is potentially useful for identifying patients with localized prostate cancer at risk of disease progression.

15:30 3802. Monitoring Prostate Cancer Progression with Diffusion Weighted Imaging: Variability of Apparent Diffusion Coefficient Measurements with ROI Placement Technique and Time Veronica Anna Morgan1, Sophie F. Riches2, Nicholas Van As3, Nandita M. deSouza2 1Royal Mardsen Hospital NHS Trust, Sutton, UK; 2Institute of Cancer Research, Sutton, UK; 3Royal Marsden NHS Trust, Sutton, UK

This study investigates use of diffusion-weighted MRI for monitoring prostate cancer progression in patients on active surveillance. Initially, variability in apparent diffusion coefficient (ADC) over whole prostate with time and in tumor with ROI placement techniques was investigated. 19 patients studied at baseline and 2-years showed significant reduction (p=0.03) in fast component of ADC, suggesting reduction in perfusion over this time. Tumor ADCs were significantly lower (p=0.001) using ADC-derived compared with T2-derived ROIs. There was no significant difference in ADC in patients that progressed to radical treatment compared to those that did not indicating that ADC may not reliably be used to monitor disease progression.

14:00 3803. Quantification of Metabolites in HR-MAS Spectra of Human Prostate Biopsy Tissues Using ERETIC and the QUEST Algorithm Vickie Yi Zhang1, Helena Gurascier1, Mark Albers1, 2, Helene Ratiney3, Laura Tabatabai, Jeff Simko, Ying Lu1, Daniel Vigneron1, Mark Swanson1, John Kurhanewicz1, 2 1University of California, San Francisco, San Francisco, California , USA; 2UC Berkeley / UC San Francisco, San Francisco, California , USA; 3 Université de Lyon, Villeurbanne, France

An automated time domain based fitting algorithm (QUEST) was used with the Electronic Reference To access In vivo Concentrations (ERETIC) quantification standard to determine the absolute concentrations of 19 metabolites in 106 1H high resolution magic angle spinning (HR-MAS) spectra of human prostate biopsy tissues. The combination of QUEST and ERETIC provided robust metabolite quantification with minimal user input and potential for human bias. Nine metabolites (PC, GPC, choline, PE, lactate, alanine, citrate, polyamines, glutamine and glutamate) were found to be significantly different between healthy glandular, stromal, and prostate cancer tissues.

14:30 3804. Comparison of 2D JPRESS and 2D L-COSY on Detecting Polyamines and Citrate Metabolites for Prostate Study Hui Liu1, Ming-Ying Su, Mark Hamadard2, Hyeon Man Baek, Seung-Hong Ha, Tugan Muftler, Orhan Nalcioglu 1University of California,Irvine, Irvine, California , USA; 2University of California,Irvine, USA

Polyamines are new promising biomarkers for prostate cancer study. It was claimed by other researchers that combining polyamine levels and traditional (Choline+Creatine)/Citrate ratio will improve the specifity and sensivity. Traditional 1D MRS and 2D JPRESS suffered from over-crowded and complex spectrum because of limited spectral resolution and strong coupling effects. 2D L-COSY method has better spectral dispersion of J cross-peaks and is able to detect short TE metabolites compared to 2D JPRESS. Thus, Combined 2D L-COSY and MRSI is a new promising strategy for better detection and monitoring prostate cancer if using polyamine as target biomarker.

15:00 3805. The Clinical Value of MR Elastography in Diagnosis of Prostate Cancer at 3.0T Saying Li1, Min Chen1, Xuna Zhao2, Shuguang Hu2, Cheng Zhou1 1Beijing Hospital, Beijing, People's Republic of China; 2Philips Medical System, Beijing, People's Republic of China

MR elastography is a new imaging tool capable of assessing the viscoelastic properties of tissue. The purpose of our study was to investigate the clinical value of MRE in diagnosis of prostate cancer at 3.0T, and to assess the viscoelastic properties of prostate cancer and prostatitis. Eight patients with prostate cancer and 10 patients with prostatitis were evaluated by MRE. We found the viscosity and elasticity were significantly higher in the lesions with prostate cancer than with prostatitis. In conclusion, MRE can visualize the different viscoelasticity between prostate cancer and prostatitis, and has great potential in diagnosis of prostate cancer.

15:30 3806. Integration of MRS and DWI in the Diagnosis of Prostate Cancer Dong Jiao Lu1, 2, Xue Mei Guo, 12, Fei Yu Li, 12, Jue Zhang1, Xiao Ying Wang, 12, Jing Fang1 1Peking University, Beijing, People's Republic of China; 2Peking University First Hospital, Beijing, People's Republic of China

Magnetic Resonance Spectroscopy (MRS) and Diffusion Weighted Imaging (DWI) play different roles in the detection of prostate cancer (Pca). Their importance in diagnosis may be reflected by their weights. In this study, we make an effort to investigate the performances of MRS and DWI in the detection of Pca by Fisher linear discriminant analysis.

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14:00 3807. Characterization of Prostate Cancer with Perfusion MR Imaging Louisa Bokacheva1, Kiran Sheikh1, Henry Rusinek1, Artem Mikheev1, Danny Kim1, Xiangtian Kong1, Jonathan Melamed1, Bachir Taouli1 1New York University School of Medicine, New York, USA

Thirty patients with confirmed prostate cancer were assessed with conventional static T2-weighted imaging and perfusion MRI. Ten patients underwent radical prostatectomy, and excised prostates were evaluated by histological analysis. Maps of blood-tissue transfer constant Ktrans and volume fraction of extracellular extravascular space (EES) were created using Tofts model. For ROIs placed in muscle, normal peripheral zone, normal central gland, and tumor, highly significant differences were found in values of Ktrans and EES fraction. Discrimination of tumor from normal tissue resulted in areas under the ROC curves of 0.88 for Ktrans and 0.78 for EES volume fraction.

14:30 3808. High Spatio-Temporal Resolution Dynamic Contrast Enhanced MRI of the Prostate Akira Kawashima1, Manojkumar Saranathan2, Sandeep Gupta3, Dan Rettmann2 1Mayo Clinic, Rochester, Minnesota, USA; 2Global Applied Science Lab, GE Healthcare, Rochester, Minnesota, USA; 3Global Research Center, GE Healthcare, Niskayuna, New York, USA

Dynamic gadolinium contrast enhanced MR imaging (DCEMRI) of the prostate has been shown to improve the detection, localization and tumor staging of prostate carcinoma and to supplement the limitations of morphologic T2-weighted imaging. Recently, fat suppressed 3D SPGR sequences have been utilized for DCEMRI of the prostate with the usual trade-off between spatial and temporal resolution. There has been a renewed interest in pharmacokinetic modeling of tumors, specifically in generating quantitative parametric maps (Ktrans and Vep), due to their role in assessment of response to medical therapy. However, the generation of reliable parametric maps demands a high spatio-temporal resolution acquisition methodology, seldom achieved or at the cost of spatial coverage. In this study, we investigated the use of a highly accelerated fat saturated elliptic centric TRICKS acquisition for dynamic high spatial and temporal resolution imaging of the prostate and its potential utility in pharmacokinetic modeling on a 3T system.

15:00 3809. 3 Tesla High Spatial Resolution Dynamic Contrast Enhanced and T2-W Prostate Magnetic Resonance Imaging (MRI): Detection of Extracapsular Extension and Staging of Prostate Cancer in Routine Clinical Practice Boris Nicolas Bloch1, Tania Velez1, Robert E. Lenkinski1, Herbert Y. Kressel1, Daniel DaCosta1, Martin P. Smith1, Ivan Pedrosa1, Mary G. Hochman1, Long Ngo1, Elizabeth Genega1, Neil M. Rofsky1 1Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA

We evaluated the sensitivity and specificity of high spatial resolution dynamic contrast enhanced (DCE) MRI combined with T2-W endorectal coil MRI at 3 Tesla for assessment of extracapsular extension and staging of prostate cancer in a routine clinical setting, using histopathology as the reference standard. The sensitivity, specificity, PPV and NPV for ECE for all readers was 76%, 90%, 78% and 89%, respectively; for the most experienced reader 83%, 93%, 83% and 93%, respectively. The staging accuracy (AUC) for all readers was 87% (range: 78-93%). This study demonstrates the utility of combined high spatial resolution DCE and T2-W MRI at 3T, yielding improved assessment of ECE and high staging accuracy of prostate cancer in routine clinical practice.

15:30 3810. simultaneous Diffusion and Perfusion Imaging Provides Complementary Functional Data That Can Be Used in the Pre- And Post Therapeutic Disease Management in Prostate Cancer Patients Greetje Groenendaal1, Cornelis A.T. van den Berg1, Ellen M.A. Roeloffzen1, Jan G. Korporaal1, Peter R. Luijten1, Marco van Vulpen1, Uulke A. van der Heide1 1University Medical Center Utrecht, Utrecht, Netherlands

Dynamic contrast-enhanced (DCE) and diffusion-weighted imaging (DWI) have both shown to be able to discriminate benign from malignant regions in the prostate. As contrast generated by these techniques stems from different physiology, we have studied the correlation between changes in perfusion and diffusion of suspicious regions found with both imaging techniques. We found that simultaneous diffusion and perfusion imaging provides complementary functional data that can be used in the pre- and post therapeutic disease management in prostate cancer patients.

Advances in Tumor MRS Hall D Monday 14:00-16:00

14:00 3811. Histone Deacetylase Inhibition by MRS: Comparison of in Vitro and in Vivo Studies Madhuri Sankaranarayanapillai1, James A. Bankson1, Qing Yuan1, Hagit Dafni2, Douglas D. Webb1, Ashutosh Pal1, Edward F. Jackson1, Juri G. Gelovani1, William P. Tong1, Sabrina M. Ronen2 1U.T. M.D. Anderson Cancer Center, Houston, USA; 2University of California at San Francisco, San Francisco, USA

Histone deacetylase (HDAC) inhibitors (HDACI) are emerging as promising antineoplastic agents. We previously showed that intracellular levels of 19F MRS-detectable Boc-Lys-TFA-OH (BLT) are correlated with HDAC activity and that this method can be used in both cells and tumors to monitor HDAC inhibition. Here we show that in contrast to our in vitro observations, phosphomonoester levels determined by 31P MRS did not change in PC3 tumor xenografts following SAHA treatment. Our results suggest that 19F MRS of BLT is a potential noninvasive method of monitoring HDAC activity in vivo whereas PC is not a reliable marker of HDAC inhibition.

14:30 3812. Improving in Vivo Brain Tumor Phenotyping with MRS Pattern Perturbation and Pattern Recognition Analysis Rui Vasco Simões1, 2, Margarida Julià-Sapé1, 3, Sebastián Cerdán4, Carles Arús1, 3 1Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain; 2Universidade de Coimbra, Coimbra, Portugal; 3Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Cerdanyola del Vallès, Spain; 4Instituto de Investigaciones Biomédicas “Alberto Sols” UAM-CSIC, Madrid, Spain

MRS pattern recognition analysis is becoming an invaluable tool for the non-invasive classification of human brain tumors but still fails to fully discriminate between certain types and grades. Based on the reproducible effects of hyperglycemia in a mouse model of brain glioma, as monitored by 1H MRS, we have recently suggested MRS pattern perturbation as a potential tool for increasing the dynamic range for brain tumor classification in vivo. Here we show preliminary results that point towards pattern recognition analysis as a fast and accurate method for discriminating MRS patterns upon such metabolic challenge.

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15:00 3813. Choline Production and Her-2/neu Expression in Breast Cancer Measured by MRI/MRSI Wenlian Zhu1, Baasil Okollie1, Zaver Bhujwalla1, Dmitri Artemov1 1Johns Hopkins University, Baltimore, Maryland, USA

The ability to image the Her2neu receptor with MRI allows us to investigate ‘molecular-functional’ relationships between receptor expression and metabolism. We typically observe a heterogenous distribution of the Her2neu receptor in tumors. Since we previously observed increased phosphocholine in breast epithelial cells transfected with the erbB2 (Her2neu) oncogene, here we have examined the relationship between Her2neu expression and the distribution of total choline.

15:30 3814. Choline Kinase Over Expression Increases Drug Resistance and Invasion in MCF7 Breast Cancer Cells Tariq Shah1, Flonne Wildes1, Marie-France Penet1, Paul T. Winnard Jr. 1, Kristine Glunde1, Dmitri Artemov1, Venu Raman1, Ellen Ackerstaff1, Zaver M. Bhujwalla1 1Johns Hopkins School of Medicine, Baltimore, USA

Increased expression of choline kinase (Chk) is one of the major factors contributing to the elevated phosphocholine and total choline signals observed in MRS studies of tumors. We previously observed that si-RNA-mediated down-regulation of Chk in breast cancer induced differentiation and increased the effect of treatment with 5-fluorouracil (5-FU). Here we have shown that overexpression of Chk in poorly invasive MCF-7 breast cancer cells increased phosphocholine and resulted in a significant increase of resistance to 5-FU as well as exclusion of rhodamine-123. A small but significant increase in invasion was also observed although cell proliferation rates were not significantly altered.

Advances in Tumor MRI Hall D Tuesday 13:30-15:30

13:30 3815. Optimization of Acquisition and Post Processing Strategies for Deconvolution-Based Perfusion Quantification of Breast Tumors Using T1-Weighted DCE MRI Smitha Makkat1, Robert Luypaert1, Steven Sourbron2, Tadeusz Stadnik1, Peter Van Schuerbeek1, Martine Dujardin1, Johan De Mey1 1Vrije Universiteit Brussel, Brussels, Belgium; 2University Munich - Grosshadern Hospital, Munich, Germany

Tumor Blood Flow (TBF) assessment can become crucial in anti-angiogenic therapies. The TBF derived using deconvolution analysis of high bolus DCE-MRI were higher than the PET values. Here we explore three key aspects of acquisition/ post processing strategies to improve the accuracy of TBF assessment : contrast dose, FA and tracer concentration estimation. We demonstrate that with the existing high bolus method, simultaneous accomplishment of an unsaturated AIF curve and a tissue curve with adequate SNR can not be met. Instead, use can be made of a prebolus technique in a low FA sequence with RE as the concentration estimate.

14:00 3816. N-Nitrosodiethylamine-Induced Pig Liver Hepatocellular Carcinoma Model: MRI with Gd-BOPTA Enhancement Yi Xiang Wang1, Xiao Li2, Xiao Ping Zhou2, Cheng Wei Tang2 1The Chinese University of Hong Kong, Shatin, People's Republic of China; 2Sichuan University, West China Hospital, Chengdu, People's Republic of China

Liver HCC with a cirrhosis background was induced in three China Taihu pigs by N-nitrosodiethylamine. Histology and MRI findings of pre- and post- Gd-BOPTA-enhancement showed that all highly, moderately, and poorly differentiated HCC tumors were identified in the pig livers. Gd-BOPTA significantly increased the sensitivity of MRI detection of HCC nodules. That HCC nodules of various differentiations with a variety of MRI signals and enhancement patterns co-exist in the same liver with comparable size to human anatomy provides a versatile animal model both for therapeutic investigation and diagnostic technology development, the latter includes MRI sequence optimization and contrast agent research.

14:30 3817. Monitoring of the Hepatocellular Carcinoma Growth by 1H and 23Na MRI Andriy Babsky1, Stephen Topper1, Shenghong Ju1, Stacy Bennett1, Gordon McLennan1, Navin Bansal1 1Indiana University, Indianapolis, USA

Water apparent diffusion coefficient (ADC), total tissue Na+ and intracellular Na+ were monitored in hepatocellular carcinoma (HCC) in rats and in the surrounding liver tissue using diffusion weighted 1H, single-quantum (SQ) 23Na and triple-quantum-filtered (TQF) 23Na MRI. The tumor water ADC was ~60% higher compared to the nearby healthy liver tissue but did not change considerably during 28 days of tumor growth (double time ~2.2 days). The HCC growth was associated with an increase in both SQ and TQF 23Na SI especially after 21 days post-cell inoculation reflecting possible changes in intracellular ionic metabolism and in extracellular space.

15:00 3818. Quantification of Tumor Necrosis Using Functional MR Imaging with Pathologic Correlation Ihab R. Kamel1, Manon Buijs, Josephina A. Vossen, Eleni Liapi, Kwang H. Lee, Michael Torbenson, David A. Bluemke, Jean-Francois H. Geschwind 1Johns Hopkins Hospital, Baltimore, Maryland, USA

This study compares ADC values of Vx-2 tumors implanted in the rabbit liver to the degree of cellular necrosis at careful pathologic correlation. Mean tumor size was 2 cm (SD 0.8 cm), and mean tumor ADC value was 1.98 E -3 mm2/sec. Mean tumor necrosis at pathology was 49% (CD 24%) as measured by ImageJ software. The correlation between liver ADC and tumor necrosis at pathology had r value of 0.67 indicating that functional MR imaging using diffusion-weighted acquisitions and ADC values may be used as biomarker of tumor necrosis.

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13:30 3819. Dual Blood Supply Model and Analysis for Liver DCE-MRI Studies James d'Arcy1, Matthew Orton1, Dow-Mu Koh2, Anwar Padhani3, Martin Leach1, David Collins1 1Institute of Cancer Research, Sutton, UK; 2Royal Marsden NHS Foundation Trust, Sutton, UK; 3Mount Vernon Hospital, Northwood, UK

Existing pharmaco-kinetic models used in evaluation of DCE-MRI data rely on a single input function to describe the plasma concentration of contrast agent. The liver, a common site for metastatic disease, is supplied with blood from the hepatic artery and portal vein. Using a dual blood supply, we demonstrate successful model based estimations of the Hepatic Perfusion Index, in addition to conventional pharmaco-kinetic parameters such as Ktrans, ve and kep in both lesions and normal liver. Data analysis and visualization were performed using our software platform (MRIW) designed for the evaluation of DCE-MRI clinical trial data.

14:00 3820. Semi-Automatic Segmentation of Lung Tumors in MRI Images of a Mouse Tumor Model Johannes T. Heverhagen1, 2, Volker Dicken3, Peter Wassenaar1, Georgeta Mihai1, Michael V. Knopp1, Michael A. Pereira1, Petra Schmalbrock1 1The Ohio State University, Columbus, USA; 2Philipps University, Marburg, Germany; 3MeVis, Bremen, Germany

The purpose of this study is to evaluate a semi-automatic tool that measures tumor volume as well as RECIST and WHO assessment criteria after initial seed point placement by an operator. Lung tumor bearing mice were imaged in a 4.7T small animal MRI scanner. The images were analysed using semiautomatic analysis tool. The results show a good correlation with histological tumor volumes. Even tumors located on the diaphragm in close proximity or with contact to the liver were segmented and their volumes were measured correctly. The study demonstrated the feasibility of semi-automatic tumor volumetry in MRI data sets of mouse lung tumors with minima user interaction.

14:30 3821. Comparison of Biodegradable Macromolecular MRI Contrast Agents with Gd-(DTPA-BMA) and Albumin-(Gd-DTPA) in Tumor Characterization with DCE MRI Yi Feng1, Eun-Kee Jeong, Dennis Parker, Zheng-Rong Lu1 1University of Utah, Salt Lake City, Utah, USA

The effectiveness of the biodegradable macromolecular MRI contrast agents, GDCC and GDCP, in tumor characterization with DCE MRI was evaluated in tumor bearing mice and compared to a low molecular weight contrast agent, Gd(DTPA-BMA), and a non-degradable macromolecular agent, albumin-(Gd-DTPA). The tumor vascular permeability determined by biodegradable macromolecular contrast agents were similar to that determined by albumin-(Gd-DTPA).

15:00 3822. Multiexponential T2 Analysis of Astrocytoma Cells in Agar Pamela R. Jackson1, Roland G. Henry2, Tracy R. McKnight2 1University of California, Berkeley and San Francisco, San Francisco, California , USA; 2University of California, San Francisco, San Francisco, California , USA

A well-known characteristic of malignant glioma is an increase in cell density with increasing malignancy of the tumor. We created a simple model for tissue using astrocytoma cells suspended in agar at different densities to better understand the effects of cell density on the T2 signal. Monoexponential, biexponential, and non negative least squares algorithms were used to fit the data, and the Spearman Rank test was used to test correlation . We identified two components associated with agar, the shortest of which dominated the negative correlation of T2 with cell density.

Tumor Perfusion & Permeability Measurements Hall D Wednesday 13:30-15:30

13:30 3823. Physiologically Based Multiple Reference Tissue Method (PB-MRTM) for Arterial Input Function (AIF) Estimation Cheng Yang1, Gregory S. Karczmar1, Masoom A. Haider2, Walter M. Stadler1 1University of Chicago, Chicago, Illinois, USA; 2University of Toronto, Canada

We present a method which simultaneously estimates the AIF and physiologic parameters of the patients including the cardiac output (CO) using the contrast agent dynamic data in 2 or more reference tissues obtained from normal tissues and/or tumor sub-regions. Clinical applications of the PB-MRTM showed that it can provide realistic and consistent estimate of the AIF and CO in both MRI and CT studies, suggesting that it can provide an accurate estimate of the AIF. On contrast, the AIFs directly measured from arteries in DCE-MRI studies were inaccurate, indicated by that the inferred CO was unrealistically large.

14:00 3824. Systematic Modeling of Perturbations Effects in the Arterial Input Function with Implication for DCE-MRI Evaluation Dee H. Wu1, 2, Rajibul Alam3 1University of Oklahoma Health Science Center, Oklahoma City, USA; 2University of Oklahoma , Norman, USA; 3University of Oklahoma , Norman, USA

Recently there has been considerable interest surrounding how the arterial input function (AIF) is applied to DCE-MRI analysis which has led to some controversy in the choice of implementation. We model and evaluate the impact of variation due to injection process (delay and dispersion), and its measurement, and analysis. To model these processes we take independent AIF functions (by modeling its change and predict DCE-MRI variation of pharmacokinetic parameters k12 and k21 and amplitude. We consider population, individualized curve fits in this analysis. It appears that with most dramatic changes in pharmacokinetic parameters were illustrated at impulsive positions for time shifts and produce dramatic increases with even moderate changes in dispersion. This illustrates the potential for large pharmacokinetic changes may occur even with moderate shifts in time and dispersion of the AIF.

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14:30 3825. Feasibility of Using Limited-Population-Based Average R10 for Pharmacokinetic Modeling of Osteosarcoma Dynamic Contrast-Enhanced MRI Data Wei Huang1, 2, Ya Wang1, Jason A. Koutcher1 1Memorial Sloan Kettering Cancer Center, New York, New York, USA

In this DCE MRI study of 18 patients with osteosarcoma, we show that it is feasible, as well as practical, to use a uniform, limited-population-based average R10 for pharmacokinetic modeling of osteosarcoma DCE MRI data from a larger population when it is not possible to acquire proton density images for individual R1 measurement.

15:00 3826. Sensitivity to Tumor Micro-Vasculature Without Contrast Agents in High Spectral and Spatial Resolution MR Images Sean Foxley1, Xiaobing Fan1, Devkumar Mustafi1, Chad Haney1, Marta Zamora1, Erica Markiewicz1, Gregory S. Karczmar1 1University of Chicago, Chicago, Illinois, USA

High spectral and spatial resolution (HiSS) datasets of a rodent tumor model were acquired using echo-planar spectroscopic imaging. Details of the water line for each voxel imaged were analyzed and images were produced. Pre-contrast HiSS images were compared with a “gold standard for micro-vasculature detection - gradient echo contrast difference images [using a blood pool contrast agent (iron-oxide particles)]. HiSS images were found to have a sensitivity and specificity of 75 ± 13% and 74 ± 10% to tumor micro-vasculature in the tumor rim, respectively. Results indicate HiSS imaging is sensitive to tumor micro-vasculature without the need of exogenous contrast.

13:30 3827. DCE-MRI Rat Cerebral Glioma Blood Volume Determination with Extravasating CR Xin Li1, William D. Rooney1, Csanad Varallyay1, James A. Goodman1, Audrey Selzer1, Ian Tagge1, Martin M. Pike1, Edward A. Neuwelt1, Charles S. Springer, Jr. 1 1Oregon Health & Science University, Portland, USA

Dynamic-Contrast-Enhanced (DCE) MRI data were obtained from rat brain gliomas that exhibited rapid contrast reagent extravasation. Despite this, analysis with a three-site-exchange pharmacokinetic model, which admits finite equilibrium water exchange kinetics, allows tumor blood volume determination. Parameter sensitivity was tested with grid searches of 2D parametric error surfaces.

14:00 3828. Leakage Corrected RCBV Measurements Using Prebolus Dosing: Applications in Differentiating Glioma Recurrence from Post-Treatment Effect at 3T Field Strength Leland S. Hu1, Leslie C. Baxter1, Thomas Paine1, John p. Karis1, Burt G. Feuerstein1, Scott Beeman1, Josef Debbins1, James Pipe1, Michael Purcell1, Joseph E. Heiserman 1Barrow Neurological Institute, Phoenix, USA

We set out to determine the necessary preload Gd-DTPA dosage to produce T1W leakage-corrected relative cerebral blood volume (rCBV) values which distinguish glioma recurrence from post-treatment radiation effect (PTRE) using Dynamic Susceptibility Contrast (DSC) MRI at 3T field strength. rCBV was measured following sequentially increasing preload dosage and correlated directly with surgical tissue specimen histopathology. We found no significant change in rCBV values over increasing preload dosage. Possible explanations include decreased T1-weighting at 3T, and effects from steroid therapy, although further work is needed to resolve other possible explanations.

14:30 3829. Dynamic Contrast Enhanced Derived Cerebral Blood Volume Correlates Better with Leak Correction Than with No Correction for Vascular Endothelial Growth Factor, Micro Vascular Density and Grading of Astrocytoma Mazhar Husain1, Mohammad Haris2, Nuzhat Husain1, Anup Singh3, Savita Srivastava1, Chhitiz Srivastava1, Sanjay Behari2, Ram Kishore Singh Rathore3, Sona Saksena2, Rakesh Kumar Gupta2 1CSMM University, Lucknow, India; 2Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India; 3Indian Institute of Technology, Kanpur, India

Perfusion magnetic resonance imaging has made it possible to assess the microvasculature in-vivo. In this study, quantification of both hemodynamic and physiological indices in 64 cases of astrocytoma was done using dynamic contrast enhanced MRI and correlated with immunohistochemically obtained microvessel density (MVD) and vascular endothelial growth factor (VEGF) expression. The corrected relative cerebral blood volume (rCBV) for leakage of contrast in to interstitium space correlated strongly with MVD, VEGF and grades of astrocytomas compared to the uncorrected rCBV; and was able to classify 100% low grade astrocytoma from high grade astrocytoma precisely

15:00 3830. Molecular Aspects of NMR Shutter-Speed Discrimination of Malignant and Benign Breast Tumors Charles S. Springer, Jr. 1, 2, Wei Huang2, Xin Li1, Elizabeth A. Morris2, Luminita A. Tudorica3, William D. Rooney1 1Oregon Health & Science University, Portland, Oregon, USA; 2Memorial Sloan Kettering Cancer Center, New York, New York, USA; 3State University of New York, Stony Brook, New York, USA

In a (Dynamic-Contrast-Enhanced) DCE-MRI study of 22 patients with suspicious breast lesions, Shutter-Speed pharmacokinetic model analysis significantly improved diagnostic specificity compared to the institutional clinical breast MRI protocol. Specifically, there is an NMR shutter-speed effect on the Ktrans parameter for only the malignant tumors. Molecular aspects of this are discussed.

13:30 3831. Simultaneous Estimation of T1 and T2* with a 2D Radial Multi Gradient Echo Sequence: Proof of Concept in a Phantom and in Tumor Bearing Mice in the Presence of Respiratory Motion Julien Vautier1, 2, Melanie Heilmann1, 2, Christine Walczak1, 2, José Manuel Pérez-Sánchez3, Andreas Volk1, 2 1Institut Curie, Orsay, France; 2INSERM U759, Orsay, France; 3Universidad Complutense de Madrid, Madrid, Spain

We developed a 2D-radial RF-spoiled multi gradient echo technique on a 4.7T small animal MR system for simultaneous dynamic T1 and T2* estimation at high temporal resolution in experimental tumors. Images (6 echoes, MTX=64) were acquired in 1.3s. T2* was estimated by a monoexponential fit. T1 was estimated from a T2* corrected steady state image combined with prior variable flip angle calibration. Motion artifact free images were obtained without respiratory triggering and reproducible T1 and T2* were obtained in mice and a compartmented phantom. T1 and T2* were validated on the phantom using inversion-recovery and multi gradient echo techniques.

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14:00 3832. An Exploration of the Relation Between Angiogenic Status and Susceptibility Contrast in Brain Tumors Arvind P. Pathak1, Doug Ward2, Kathleen M. Schmainda2 1The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA; 2Medical College of Wisconsin, Milwaukee, Wisconsin, USA

In this study, we employed a novel simulation methodology called the finite perturber model (FPM) that enables us to study susceptibility-induced contrast arising from arbitrary microvascular geometries in 3D, such as those typically observed during tumor angiogenesis. Here, the FPM in conjunction with computer-generated “in silico” 3D tumor microvasculature that conforms to the different stages of brain tumor angiogenesis, was used to explore the relation between angiogenic status and susceptibility-based MR contrast.

14:30 3833. Differential Sensitivity to Vascular Permeability Using Low-MW and High-MW Contrast Agents for DCE-MRI Hagit Dafni1, 2, Sabrina M. Ronen1, 2 1The University of Texas M. D. Anderson Cancer center, Houston, USA; 2University of California, San Francisco, USA

The purpose of this study was to compare the sensitivity of low-MW (GdDTPA) and high-MW (albumin-GdDTPA) contrast materials to anti-vascular therapy in a prostate cancer bone metastases model. DCE-MRI performed before and after short-term interventional therapy combining imatinib and paclitaxel, detected significant reduction in permeability to albumin-GdDTPA but not to GdDTPA, reflecting differences in mechanism of vascular permeability and pharmacokinetics of the two agents. This differential sensitivity suggests that development of macromolecular contrast agents for clinical use and their incorporation in clinical DCE-MRI will provide more sensitive and selective detection of early response to some anti-vascular therapies.

15:00 3834. Differentiation of Benign Fibroadenomas from Breast Cancer with Dynamic MRI: Comparison of a Novel Macromolecular Contrast Agent and Gadoteridol Hans Juergen Raatschen1, 2, Yanjun Fu2, David M. Shames2, Robert C. Brasch2 1Charite Campus Benjamin Franklin, Berlin, Germany; 2University of California San Francisco Medical Center, San Francisco, California , USA

This animal study was performed to evaluate the suitability of two gadolinium-based contrast agents, the FDA-approved gadoteridol, and a new macromolecular polyethylene glycol (PEG)-based dendrimer, intended for clinical development, for differentiation of benign from malignant breast tumors in an animal model.The Gd-DO3A-conjugated PEG-core dendrimeric contrast medium PEG12000-Gd-DO3A26 was proven to be superior to the FDA-approved gadoteridol for differentiating benign fibroadenomas from breast cancer based on estimates of tumor fractional plasma volume, fPV, and vascular endothelial leakiness, KPS. The potential for differentiating normal tissues from mammary tumors was similar for both contrast agents.

13:30 3835. Investigating the Influence of Phased Arrays and Parallel Imaging for Input Function Definition in DCE-MRI Ross A. Little1, Caleb Roberts1, Yvon Watson1, Marietta Scott2, Geoff J. Parker1 1University of Manchester, Manchester, UK; 2AstraZeneca, Macclesfield, Cheshire, UK

Physiologically-meaningful DCE-MRI measurements of microvascular characteristics are not possible without the accurate acquisition of an arterial input function (AIF). This study uses a flow phantom with independent optical measurement to investigate the accuracy of contrast agent concentration measurements taken with dynamic contrast-enhanced MRI using a quadrature body coil and a phased array coil with and without SENSE parallel imaging. Although SENSE factors lead to a reduction in SNR, reduced scan times allow improved measurement of the rapid changes in concentration associated with input function measurement, as confirmed by comparison with our optical measurements.

14:00 3836. The Role of Temporal Resolution in Determining Pharmacokinetic Parameters from DCE-MR Data Marieke Heisen1, Xiaobing Fan2, Thorsten Twellmann1, Johannes Buurman3, Natal A.W van Riel1, Gregory S. Karczmar2, Bart M. ter Haar-Romeny1 1Technische Universiteit Eindhoven, Eindhoven, Netherlands; 2University of Chicago, Chicago, Illinois, USA; 3Philips Medical Systems, Best, Netherlands

In DCE-MRI of the breast, a wide variety in parameter settings is possible. This especially holds for the temporal resolution of the dynamic series. Given the high expectations of pharmacokinetic modeling, it is crucial to analyze the effect of temporal resolution in determining pharmacokinetic parameters. We investigated this issue by deriving low-temporal-resolution image-series from a high-temporal-resolution original via a reorganization of the k-space data. The initial experiment, as presented here, was performed on data from model tumors in rats. Fitting of the Kety two-compartment pharmacokinetic model demonstrated that with decreasing temporal resolution, Ktrans and ve get progressively under- and overestimated. <

14:30 3837. A Method for Updating the Aterial Input Function Each Cardiac Cycle with Flow Compensation Dustin K. Ragan1, Emilio Esparza-Coss1, James Andrew Bankson1 1M. D. Anderson Cancer Center, Houston, Texas, USA

DCE-MRI is sensitive to the local tissue vascular properties, and has shown promise in monitoring the treatment of disease. A common approach to quantification is to relate the time course of concentration of a contrast agent in blood and tissue by a model. Measurement of the blood concentration, or arterial input function (AIF), can be confounded by the cardiac cycle and flow effects. We measured high temporal resolution AIFs in a mouse by acquiring a projection through the short axis of the heart and compensated for flow effects by combining the excitation pulse with a spatial suppression pulse.

15:00 3838. Novel Procedures to Derive the Impulse Response Function and Its Mathematical Model for DCEMRI Xiaobing Fan1, Gregory S. Karczmar1 1University of Chicago, Chicago, Illinois, USA

Accuracy of cancer diagnosis with dynamic contrast enhanced MRI (DCEMRI) could be improved by eliminating the arterial input function (AIF) effects and calculating the ‘impulse response function’ (IRF) of the tissue. Here, we describe a simple and effective deconvolution algorithm and use numerical simulations to study the performance of this algorithm with a variety of contrast concentration vs. time curves. A general mathematical model of the IRF with physiological parameters relating to blood flow/capillary permeability, and contrast media distribution volume was derived. The results suggest that the deconvolution procedure developed in this research can be employed to analyze clinical DCEMRI data.

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Gynecological Cancer Hall D Thursday 13:30-15:30

13:30 3839. Apparent Diffusion Coefficient Value for Differentiating Pathology in Cervical Cancer at 3 Tesla Gigin Lin1, Koon Kwan Ng1, Yau Yau Wai1, Jiun Jie Wang1, Chyong Huey Lai1, Yu Ting Huang1, Kung Chu Ho1, Tzu Chen Yen1 1Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taipei, Taiwan

To investigate the feasibility of using ADC value from 3T MRI for differentiating pathology categories of cervical cancer, 126 patients were enrolled. Mean ADC value of adenocarcinoma (0.96 ± 0.21 x 10-3 mm2/s) was higher than that of squamous cell carcinoma (0.84 ± 0.11 x 10-3 mm2/s), adenosquamous carcinoma (0.79 ± 0.10 x 10-3 mm2/s), or small cell carcinoma (0.53 ± 0.10 x 10-3 mm2/s). Significant difference (p<0.001) was noted between groups. Therefore, ADC value from 3.0T MRI-DWI is promising in differentiating pathology types of cervical cancer.

14:00 3840. High B-Value Diffusion-Weighted MR Images of Uterine Pathologies Mayumi Takeuchi1, Kenji Matsuzaki1, Hiromu Nishitani1 1University of Tokushima, Tokushima, Japan

We evaluated benign and malignant uterine pathologies by high b-value diffusion-weighted images (DWI) and corresponding isotropic ADC maps. All malignant lesions (44 endometrial cancers/sarcomas: 0.86 +/- 0.20, 5 myometrial sarcomas: 0.78 +/- 0.30 and 34 cervical cancers: 0.91 +/- 0.21) showed very high intensity on DWI. Benign endometrial polyps/hyperplasia (1.58 +/- 0.36) showed iso to intermediate intensity on DWI. However cellular leiomyomas and some degenerated leiomyomas showed high intensity on DWI, benign leiomyomas including these lesions (1.30 +/- 0.28) could be distinguishable from myometrial sarcomas by measuring ADC (p<0.01).

14:30 3841. Diffusion Weighted Imaging of the Uterus : Regional ADC Variation with Oral Contraceptive Usage and Comparison with Cervical Cancer Christina Messiou1, Veronica A. Morgan1, Sonali S. De Silva1, Nandita M. deSouza1 1The Institute of Cancer Research and The Royal Marsden NHS Trust, Sutton, UK

This study aims to determine ADC values for the normal regions of cervix and uterus and compare them to the ADC value of cervical cancer. The effect of the oral contraceptive pill (OCP) was also investigated.ADCs of cervical tumour are significantly lower than for cervical stroma and epithelium and may be useful in detecting stromal invasion in small lesions. Endometrial ADCs did not change with OCP usage. ADCs of the JZ however did increase with OCP usage. The small patient numbers in this ongoing study meant that these values did not reach significance.

15:00 3842. Changes in TCho/water Ratio in the Transition from Pre-Invasive to Invasive Cervical Cancer Using in Vivo MR Spectroscopic Imaging Sonali S. De Silva1, Geoffrey S. Payne1, Veronica A. Morgan1, Paul G. Carter2, Thomas E . Ind2, Nandita M. deSouza1 1Institute of Cancer Research and Royal Marsden Hospital NHS Trust, Sutton, UK; 2St Georges Hospital NHS Trust, Tooting Broadway, UK

The development of invasive cervical cancer is preceded by a well-defined pre-invasive stage called cervical intraepithelial neoplasia (CIN). Elevated levels of choline have previously been identified in a number of tumours including cervical cancer but whether these metabolites are elevated in CIN tissue is still unclear. This study investigates changes in the tCho/water ratios in the transition from pre-invasive and invasive cervical cancer. Twenty women (10 women with cervical cancer and 10 women with CIN disease) underwent MR imaging and spectroscopy (TR 888, TE 135 and 4 signal averages). tCho/water was calculated in tumour and non-tumour voxels in cancer patients and voxels close to the endocervix (CIN voxels) and away from the endocervix (non-CIN voxels) in CIN patients. The difference in tCho/water ratio between tumour and CIN voxels was significant (p= 0.004).

13:30 3843. Diffusion MRI Predicts Response in Advance of Tumour Size Changes in Women Receiving Chemoradiation for Cervical Cancer Vanessa N. Harry1, Scott I. Semple2, David E. Parkin1, Fiona J. Gilbert2 1Aberdeen Royal Infirmary, Aberdeen, UK; 2University of Aberdeen, Aberdeen, UK

Diffusion weighted MRI performed before and after 2 weeks of chemoradiation in women with advanced cervical cancer was found to predict their eventual response. The changes in Apparent Diffusion Coefficient also occurred significantly well before changes in tumour size as determined by conventional radiological assessment. This emphasises the potential of DWI as a biomarker capable of rapid response prediction and its promising use for offering individualised or tailored therapy

14:00 3844. Proton Spectrscopy of Gynaecology Lesions at 3.0T in a Routine Clinical Setting Martin D. Pickles1, Susanne Booth1, David J. Manton1, Martin lowry1, Julie Pounder1, Dan Siddons1, Lindsay W. Turnbull1 1University of Hull, Hull, UK

A number of groups have revealed an elevated choline peak to be an indicator of malignancy while decreasing choline levels are believed to represent a successful treatment response. In this study single voxel proton spectroscopy of gynaecology lesions were obtained by standard users utilising a 3.0T scanner. Spectra were successfully obtained from a variety of differing gynaecology lesion and the choline signal quantified. This study has demonstrated the feasibility of collecting spectroscopy from gynaecological lesions at 3.0T and the ability to quantity the choline signal by using product spectroscopy sequences by standard users.

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14:30 3845. The Utility of Diffusion-Weighted MRI in Cervical Cancer Patrick Z. McVeigh1, Aejaz M. Syed2, Michael Milosevic1, Anthony Fyles1, Masoom A. Haider1 1Univeristy Health Network, Toronto, Canada; 2The Queen Elizabeth Hospital, King's Lynn, UK

Diffusion-Weighted MRI was performed in 47 patients with cervical cancer (37 squamous carcinoma) undergoing chemoradiation therapy and 26 normal controls on a 1.5T system with a b-value of 600 s/mm2. Clinical FIGO stage, tumor volume, nodal status, interstitial fluid pressure (IFP) and oxygen measurements were recorded. Response was defined as no visible tumor 3-6 months following completion of therapy.Median ADC in cervix carcinoma is significantly lower compared to normal cervix and may be useful in the delineation of tumor boundaries for therapy planning. ADC may have predictive value in squamous tumors but further long term study will determine the ultimate clinical utility.

15:00 3846. ADC and Perfusion Signal Fraction Measurements: Feasibility in Ovarian Cancer at 3 Tesla Andrew Nicholas Priest1, Evis Sala1, Martin John Graves1, Ilse Joubert1, Mary A. McLean2, Nyree Griffin1, John R. Griffiths2, David John Lomas1 1Addenbrooke's Hospital and University of Cambridge, Cambridge, UK; 2Cancer Research UK, Cambridge, UK

Ovarian cancer response to chemotherapy is difficult to predict by standard prognostic factors. We aim to evaluate 3T DWI parameters as surrogate markers of treatment response in ovarian cancer and omental/peritoneal implants; this preliminary study demonstrates the feasibility of the method using multislice DWI data from four patients. Maps of the apparent diffusion coefficient (ADC) and the fractional signal due to perfusion were calculated. All tumours appeared bright on DWI due to their low ADC compared to surrounding tissues. Further work will assess possible correlations between DWI parameters and treatment outcome, and compare the fractional perfusion signal with DCE-MRI.

Tumor Assessment & Response Hall D Thursday 13:30-15:30

13:30 3847. Relative Changes in Tumor Perfusion (Ktrans, Ve) is Independent of Absolute Baseline T1 Values Junyu Guo1, Mark A. Rosen1, Hee Kwon Song1 1University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA

In DCE-MRI for tumor assessment, baseline T1 value is required to measure lesion perfusion. However, it can often be difficult to accurately measure T1 due to errors in the flip angle and imperfect slice profile. It is shown in this work that if the relative change in perfusion is of primary interest, e.g. as a result of treatment, the knowledge of the true baseline T1 is not required to accurately quantify these changes.

14:00 3848. Combined Use of DCE-MRI and VSI to Monitor an Antiangiogenic Therapy Against VEGF in Tumor Xenografts Stefan Zwick1, 2, Eva Christina Woenne, Ralph Strecker2, Arne Hengerer2, Matthias Taupitz3, Jörg Schnorr3, 4, Magareta Maria Mueller1, Wolfhard Semmler1, Fabian Kiessling1 1German Cancer Research Center, Heidelberg, Germany; 2Siemens Medical Solutions, Erlangen, Germany; 3Charité, Berlin, Germany; 4Ferropharm, Teltow, Germany

VSI in combination with DCE-MRI enables monitoring of early antiangiogenic tumor therapy response. Thus, tumor bearing nude mice were treated with an antiangiogenic VEGF-blocking antibody and investigated by DCE MRI and VSI before and after treatment. The decrease of Amplitude and increase of kep in treated compared to untreated tumors clearly showed therapy response. In contrast, VSI indicated no changes under treatment. Histological analysis showed lower mean vessel area fractions in treated than in untreated tumors but no significant changes in the mean vessel size which again confirms the potential and robustness of VSI and DCE-MRI.

14:30 3849. Evaluation of the Stereotaxis Radiosurgery Effects Using MRI Marcelo Andia1, 2, Cristian Tejos1, 2, Claudia Prieto1, 2, Leonardo Ramirez1, 2, Luis Meneses1, 2, Daniel Venencia1, Pablo Irarrazaval1, 2 1Pontificia Universidad Catolica de Chile, Santiago, Chile; 2Biomedical Imaging Center, Santiago, Chile

Stereotactic radiosurgery is a form of radiation therapy used to treat tumours in the brain. It consists of a few x-ray beams applied to the patient. To maximise the radiation dose in the tumour, and to minimise the damage in collateral areas, the positions and strength of the beams are given by planning softwares. However, they are not rigorously calibrated because in-vivo tests are not available. We present a method based on T2w-MRI that can be used to identify the radiotherapy effects on the irradiated tissues. This can be used to provide feedback to the planning to improve its accuracy.

15:00 3850. Decreased Choline Levels Detect Response to Rituximab Therapy in WSU-DLCL2 Human Diffuse Large B-Cell Lymphoma Xenografts Seung Cheol Lee1, David S. Nelson1, Harish Poptani1, Edward James Delikatny1, Jerry D. Glickson1 1University of Pennsylvania, Philadelphia, Pennsylvania, USA

We've performed a longitudinal MRS study on the WSU-DLCL2 human diffuse large B-cell lymphoma xenografts to see the effect of rituximab, a chimeric CD20 antibody, on the MR metabolites of the WSU-DLCL2 tumor. Both the rituximab-only therapy and rituximab plus CHOP (R-CHOP) therapy have been tested and compared with the sham-treated group and the CHOP-alone treated group respectively. tCho has decreased in the groups which have rituximab, while it did not change in the sham-treated or CHOP-alone treated groups. Rituximab induced either tumor growth delay or tumor regression depending on whether it is used alone or used with CHOP. tCho change was observed before effects on the tumor volume.

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13:30 3851. Contrast Enhanced MR-Perfusion of Renal Tumors for Monitoring of Neoadjuvant Antiangiogenic Therapy Mike Notohamiprodjo1, Steven Sourbron, Ulrike Attenberger, Christian Glaser, Gita Schoppler, Maximilian Reiser, Michael Staehler, Karin Herrmann 1University Hospitals Munich, Munich, Germany

The purpose of this study was to analyze renal tumor perfusion with MR-perfusion techniques and to evaluate the potential effects of neoadjuvant therapy on tumor perfusion. Ten patients with normal renal function, 9 patients with RCC before and 4 patients after neoadjuvant antiangiogenic therapy underwent contrast enhanced MR-perfusion. Morphologic and semiquantitative analysis was performed. Distinct morphological changes and perfusion patterns for RCC before and after neoadjuvant antiangiogenic treatment could be described and distinguished. Therefore our preliminary results suggest that contrast enhanced MR-perfusion may become a valuable diagnostic tool to monitor tumor perfusion under antiangiogenic treatment.

14:00 3852. Using Dynamic Contrast Enhanced MRI and Immunohistochemistry to Monitor Tumour Response to Tirapazamine, a Hypoxia-Targeting Chemotherapeutic Agent Lauren Jean Bains1, Jennifer H. Baker2, Andrew I. Minchinton2, Stefan Alexander Reinsberg1 1University of British Columbia, Vancouver, Canada; 2British Columbia Cancer Research Centre, Vancouver, Canada

The present study is first use of MRI to monitor tumour response to the hypoxia-activated prodrug tirapazamine. A dramatic decrease in tumour perfusion was seen in the 24 hours after tirapazamine treatment using both dynamic contrast enhanced MRI and carbocyanine staining. Implanted fiducial markers were used to spatially coregister MRI and immunohistochemistry, resulting in good correlations between the two techniques. In addition, area under the contrast-time curve (IAUC) was shown to be a potential predictor of tumour response to tirapazamine: tumours with low pre-treatment IAUC showed an improved response to treatment.

14:30 3853. Pre-Clinical Assessment of Anti-Vascular Effects of Novel Combretastatin A-4 Analogues by Dynamic Contrast Enhanced MRI Inna V. Linnik1, Steve R. Williams1, Karen E. Davies1, Alan T. McGown2, John A. Hadfield2, David L. Buckley1 1University of Manchester, Manchester, UK; 2University of Salford, Manchester, UK

The aim of the study was, firstly, to develop a robust quantitative DCE-MRI protocol for studying tumour vasculature, secondly, to deploy it for evaluation of the effects of novel anti-vascular agents. Five newly synthesized combretastatin analogues, combretastain A-4 (CA-4) and oil as a control were tested for their effects on RIF-1 tumours grown in mice 24 hours after administration. Three agents, as well as the positive control CA-4, have a significant effect on tumour vascular parameters. The results suggest that the applied DCE-MRI method may be a valuable screening tool to monitor, non-invasively, the effects of anti-vascular drugs in vivo.

15:00 3854. Diffusion-Weighted MRI as an Early Predictor of Response to Sunitinib Renu M. Stephen1, Dezheng Zhao, Robert J. Gillies 1University of Arizona, Tucson, Arizona , US

The early identification of effective cancer treatment combinations minimizes toxicities of ineffective drugs but also provides patients with better overall survival. Therefore, biomarkers that identify early response to treatment are proving to be more important in the treatment of cancer. In this study, we evaluated the role of diffusion-weighted (DW) magnetic resonance imaging (MRI) in quantitatively predicting the early response of orthotopic breast xenografts to an antiangiogenic inhibitor, sunitinib. Our results indicate the DW-MRI was able to identify early changes in tumor cellularity following treatment prior to changes in tumor volume.A

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4 Practical Considerations for GRAPPA-accelerated Readout-Segmented EPI in Diffusion-Weighted Imaging Holdsworth, Samantha No conflicts 5 Auto-Calibrated Parallel Imaging Reconstruction Using k-Space Sparse Matrices (kSPA) Liu, Chunlei No conflicts 6 Whole-Heart Imaging Using Undersampled Radial Phase Encoding and a 32-Channel Cardiac Coil Boubertakh, Redha No conflicts 7 Reconstruction of Undersampled Non-Cartesian Data using GROG-Facilitated Random Blipped Phase Encoding Seiberlich, Nicole No conflicts 8 Direct Virtual Coil (DVC) Reconstruction for Data-Driven Parallel Imaging Beatty, Philip General Electric, Ownership interest, Employment 9 Parallel Reconstruction Using Null Operations (PRUNO) Zhang, Jian No conflicts

10 A general formulation for quantitative g-factor calculation in GRAPPA reconstructions Breuer, Felix No conflicts 11 A prospective error measure for k-t SENSE Malik, Shaihan No conflicts 12 Influence of Regularization on Noise Amplification in Iterative SENSE Reconstruction Eggers, Holger Philips, Employment 13 SENSE Regularization Using Bregman Iterations Liu, Bo No conflicts 14 Time-Resolved Molecular Imaging of the “Angiogenic Switch” in Animal Models of Cancer Schmieder, Anne Kereos, Ownership interest Philips, Employment 15 Avidin-induced clearance of non-bound RGD-biotin-liposomes for target-specific MR molecular imaging of tumor angiogenesis van Tilborg, Geralda No conflicts

The ISMRM is committed to: 1. Insuring balance, independent, objectivity, and scientific rigor in all Continuing Medical Education programs, and 2. Presenting CME activities that promote improvements or quality in healthcare and are independent of commercial interests. To ensure balance, independence, objectivity, and scientific rigor in all CME programs it is the policy of the Society that any person who has influence over the content of a program designated for AMA PRA Category 1 CreditsTM must disclose any real or apparent financial interest or other relationship (i.e., grants, research support, consultant, honoraria) that the individual may have with the manufacturers, distributors or providers of any commercial products or services that may be discussed in the presentation. ISMRM does not imply that such financial interests or relationships are inherently improper or that such interests or relationships would prevent the speaker or organizer from making an objective contribution. However, it is imperative that such financial interests or relationships be identified so that participants at the CME activity may have these facts fully disclosed in advance, and may form their own judgments about the presentations. It remains for the audience to determine whether an individual’s outside interests may reflect a possible bias in either the exposition or the conclusions presented. Following are the names of all speakers, committee members, and other organizers who had influence over the program content. When individuals have disclosed real or apparent financial interests or relationships with regard to the subject matter of this meeting, the interests or relationships are described. If the individual indicated that there were no conflicts, that is shown, as well.

16 In-vivo assessments of mucus dynamics in the lungs using a Gd-Cy5.5-bilabeled contrast agent Blé, François-Xavier No conflicts 17 In Vivo Quantification of 19F Molecluar Imaging Agents with improved Accuracy and Sensitivity using Motion Correcting, Simultaneous 19F/1H Radial MRI Keupp, Jochen Philips, Employment 18 A Three-Compartment T1-Relaxation Model for Intracellular Contrast Agents: Implications for Molecular MR Imaging Strijkers, Gustav No conflicts 19 Four-Pool Modeling of Proton Exchange Processes in Biological Systems in the Presence of MRI-PARACEST Agents Li, Alex No conflicts 20 Microfabricated magnetic structures for multi-spectral contrast Zabow, Gary No conflicts 21 Inorganic core HDL applied for macrophage imaging Cormode, David No conflicts 22 In Vivo MR Imaging of Acute Thrombus Formation Using a Bimodal Contrast Agent Miserus, Robbert-Jan No conflicts 23 MntR, an MRI reporter provides cellular T1 contrast without Mn plementation. Bartelle, Benjamin No conflicts 24 Differential Interictal Activity of the Precuneus/Posterior Cingulate Cortex Revealed by Resting State fMRI at 3T in Generalized versus Partial Seizure Lui, Su No conflicts 25 Disrupted functional connectivity networks in patients with localization-related cryptogenic epilepsy Jansen, Jacobus No conflicts 26 A longitudinal MR functional connectivity study in pediatric jects from 2wks to 2yrs old using low-frequency BOLD synchronization Zhu, Quan No conflicts 27 Age-Related Connectivity Changes In Fmri Data From Children Performing A Covert Verb Generation Task Karunanayaka, Prasanna No conflicts 28 Brain connectivity during the processing of nouns and verbs: a dynamic Bayesian network analysis Qiu, Deqiang No conflicts

29 Connectivity of Complex Networks: A Monte Carlo-Based Approach for Dynamic Causal Modeling Tomasi, Dardo No conflicts 30 The functional anatomy of SMA at rest: Clustering and Connectivity independently measured with DTI and RS-fMRI Fonteijn, Hubert No conflicts 31 Higher-order contrast functions improve performance of independent component analysis of functional MRI data with low signal-to-noise ratio Schmithorst, Vincent No conflicts 32 Partitioning functional connectivity networks using “community structure” algorithms Schwarz, Adam No conflicts 33 Q-Space Diffusion Weighted MRI Analyzed with Maximizing Rician Likelihood Improves Reliability and Tissue Contrast Landman, Bennett No conflicts 34 Computation of Diffusion Function Measures in q-Space Using Magnetic Resonance Hybrid Diffusion Imaging Wu, Yu-Chien No conflicts 35 Simple harmonic oscillator based estimation and reconstruction for one-dimensional q-space MR Ozarslan, Evren No conflicts 36 Analysis of High b-Value Diffusion Images Using Fractional Order Calculus Zhou, Xiaohong No conflicts 37 Towards Better Understanding of Brain Tissue using Directional Kurtoses by Orthogonal Transformation of Diffusion Kurtosis Tensor D (KDT) Hui, Edward No conflicts 38 In Vivo Higher-Order Contrast Measured with Generalized Diffusion Tensor Imaging Using Higher-Order Tensors Liu, Chunlei No conflicts 39 Effect of Diffusion Gradient Pulse Duration on Fibre Orientation Estimation Yeh, Chun-Hung No conflicts 40 A recursive algorithm to decompose orientation distribution function and resolve intra-voxel fiber directions Yeh, Fang-Cheng No conflicts 41 Regularized er-Resolution for Diffusion MRI Nedjati-Gilani, Shahrum No conflicts

42 Spatial Normalization of the Fiber Orientation Distribution based on High Angular Resolution Diffusion Imaging Data Hong, Xin No conflicts 43 Myocardial Perfusion MRI with sliding window and CG-HYPR Ge, Lan No conflicts 44 K-t-Space Accelerated Myocardial Perfusion Jung, Bernd No conflicts 45 Evaluation of Rigid and Non-Rigid Motion Compensation of Cardiac Perfusion MRI Xue, Hui Siemens, , Employment 46 Investigating Myocardial Field Distortions During First Pass of a Gadolinium Based Contrast Agent in Perfusion Studies Ferreira, Pedro No conflicts 47 Evaluation of Microvascular Function of Residual Viable Myocardium in Infarct Zone after Percutaneous Coronary Intervention: Quantitative Myocardial Blood Flow Measurement Using Magnetic Resonance Su, Mao-Yuan No conflicts 48 Balanced SSFP Myocardial BOLD Imaging: An Initial Evaluation in Patients with Known Coronary Artery Disease Dharmakumar, Rohan No conflicts 49 Pharmacokinetic Modelling of Delayed Gadolinium Enhancment in the Myocardium Knowles, Benjamin No conflicts 50 MR Quantification of Regional Myocardial Oxygen Consumption Rate McCommis, Kyle No conflicts 51 Quantified Delayed Enhancement in Myocardial Infarction using Free Breathing Saturation Recovery SSFP Stehning, Christian Philips, Employment 52 MRI for the detection of catheter ablation scars of the right atrial isthmus in patients with atrial flutter Maintz, David No conflicts 53 A Novel Framework for Identifying DTI-Based Brain Patterns of Schizophrenia Wang, Peng No conflicts 54 Effects of genetic polymorphisms on white matter structure in schizophrenia measured with diffusion tensor imaging Anderson, Adam No conflicts

55 Tract-Specific Anisotropy Measures and Temporal Characteristics of Schizophrenia Abnormalities Carpenter, David No conflicts 56 Improved Discriminant Analysis in Schizophrenia Using Fractional Anisotropy and Apparent Diffusion Coefficient Images of Water Diffusion in Brain Ardekani, Babak No conflicts 57 The association of cerebral deficits with the symptoms in drug-naïve first episode schizophrenia: an optimized VBM and resting functional connectivity study on 3T Lui, Su No conflicts 58 Impaired memory consolidation in schizophrenia and its relationship to Dentate Gyrus and Cornu Ammonis activity: fMRI evidence Diwadkar, Vaibhav No conflicts 59 Anterior Cingulate Glutamate is Greater During Low Relative to High Dose Methadone Maintenance Dose in Heroin-Dependent Volunteers Greenwald, Mark No conflicts 60 Basal Perfusion in Adolescents at Risk for Alcohol Use Disorders Lin, Ai-Ling No conflicts 61 An Investigation of the Microstructure of Brain Tissue in Social Anxiety Disorder: A Turboprop-DTI Study Orlichenko, Anton No conflicts 62 Localization of white matter transverse relaxation time abnormalities in autism Gagnon, Yann No conflicts 63 MRI-Guided Midline Laser Glossectomy in Porcine Models: Evaluation of Safety and Efficacy for Reducing Tongue Base Volume Nour, Sherif No conflicts 64 MR targeting guidance and MR thermometry for radiofrequency ablation in patients with liver tumours on an interventional 1.5T platform Cernicanu, Alexandru No conflicts 65 MR-guided HIFU Thermotherapy with a Robotic Assistance System Krafft, Axel No conflicts 66 Volumetric HIFU Ablation under 3D Guidance of Rapid MRI Thermometry Köhler, Max Philips, Employment 67 3.0-T MRI-guided focused ultrasound ablation versus MRI-guided needle-wire placement for the pre-operative localization of non-palpable breast tumors: an experimental study Schmitz, Annemarie No conflicts

68 Endoluminal Ultrasound Applicator with an Integrated RF Coil for High-Resolution MRI-guided HICU Thermotherapy Rata, Mihaela No conflicts 69 In vivo MRI-monitoring of Gadodiamide release from phosphatidylglyceroglycerol containing thermosensitive liposomes in heated and non-heated tumors Peller, Michael No conflicts 70 In vivo visualization of an optical reporter gene expression transported by a cellular vector and locally activated by MRI guided HIFU in rat kidney Eker, Omer No conflicts 71 MRI-guided focused ultrasound-enhanced chemotherapy of 9L rat gliosarcoma: Survival study Treat, Lisa No conflicts 72 MRI Monitoring of Ultrasound-targeted Microbubbles Destruction Chow, April No conflicts 73 SAR implications of different RF shimming techniques in the body at 7 Tesla van den Bergen, Bob No conflicts 74 Comprehensive RF Safety Concept for Parallel Transmission Systems Graesslin, Ingmar Philips, Employment 75 Poseable Male and Female Numerical Body Models for Field Calculations in MRI Wang, Zhangwei No conflicts 76 Numerical field evaluation of healthcare workers when bending towards high-field MRI magnets Wang, Hua No conflicts 77 Detailed Experimental and Computational Analyses of the RF Field at 7T: Effects of the Load Content on Achieving 90o Tip Without SAR/Power Violations Hue, YiK-Kiong No conflicts 78 Dyadic Green’s functions for electrodynamic calculations of ideal current patterns for optimal SNR and SAR Lattanzi, Riccardo No conflicts 79 Specific Absorption Rate Mapping Using MR Thermometry in a Transmit-Receive Head Coil at 3.0T Oh, Sukhoon No conflicts 80 Direct SAR measurements using MRI: a phantom study of proton decoupling at 7 tesla Webb, Andrew No conflicts

81 Measurement of Electric Fields Induced in a Human jects due to Alternating Magnetic Gradient Fields and Natural Body Movements in Static Magnetic Fields Glover, Paul No conflicts 82 Human nerve stimulation threshold determination in a planar gradient system Feldman, Rebecca No conflicts 83 Diagnosis of liver fibrosis by multifrequency viscoelastic parameter evaluation in magnetic resonance elastography Klatt, Dieter No conflicts 84 Value of Shear Wave Attenuation as a Tissue Characterization Parameter in MR Elastography of the Liver Yin, Meng No conflicts 85 MR elastography of non-alcoholic steatohepatitis in the rat Salameh, Najat No conflicts 86 Evaluation of Hepatic Fibrosis with Portal Fraction and Portal Pressure Gradient using MRI Wang, Yuenan No conflicts 87 New proposal for the staging of nonalcoholic steatohepatitis: Evaluation of liver fibrosis on Gd-EOB-DTPA-enhanced MRI Tsuda, Natsuko Bayer Healthcare/Bayer Schering, Employment 88 A liver function test based on measurement of liver-specific contrast agent uptake Leinhard, Olof No conflicts 89 Gradient Echo fMRI Study of Oxygenation Changes in the Livers of Chronic Ethanol-Treated Rats Brauer, Manfred No conflicts 90 Evaluation of Hepatic Iron Concentrations by R2* Magnetic Resonance Imaging in 35 Patients with Iron Overload: Comparison of R2* Measurements at 1.5T and 3T and Validation with Liver Biopsies. Hillenbrand, Claudia No conflicts 91 Diagnosis of hepatic siderosis with a novel breath-hold multi-echo T2* sequence in patients with chronic liver disease. Chandarana, Hersh No conflicts 92 Comparison between 1.5T and 3T Single Voxel 31P MRS of Human Liver in Health and Disease Wylezinska, Marzena No conflicts 93 Midazolam sedation disrupts the corticolimbic network connection: An fcMRI study Dashdorj, Naranjargal No conflicts

94 An fMRI Study of Age Effects on Frontal-Striatal Neural Circuit Functions Zhu, David No conflicts 95 Reliable modeling of resting-state emotional networks in major depressive disorder: Applicability of exploratory structural equation modeling to small sample sizes. James, George No conflicts 96 Better Recovery Following Stroke is Associated with Normalization of Resting-State Connectivity Golestani, Ali-Mohammad No conflicts 97 A 3 T functional MRI study of the resting state networks in aging Valsasina, Paola No conflicts 98 Altered Memory Network Organisation in Left Temporal Lobe Epilepsy Associated with White Matter Structural Changes Voets, Natalie No conflicts 99 The Effect of Menstrual Cycle on Women’s Visceral Pain Perception Wang, Jianli No conflicts 100 Increased desire for food when fasted is associated with increased fMRI activation of the ventral striatum, insula and amygdala Goldstone, Anthony No conflicts 101 Reduced fronto-hippocampal connectivity in schizophrenia during associative learning: Relevance for NMDA-mediated synaptic dysplasticity Murphy, Eric No conflicts 102 Brain functional correlates of accuracy and reaction time during performance of the digit symbol stitution test in the elderly. Venkatraman, Vijay K No conflicts 103 3D Phase Contrast MRA of the Thoracic Aorta at 3T: Feasibility and Effect of Standard and Blood-Pool Contrast Agents Bock, Jelena No conflicts 104 Clinical Applications of Contrast Inflow Dynamics MRA (CIDA): Novel Approach for ECG-Gated Dynamic Contrast Enhanced MRA Fung, Maggie General Electric, Employment 105 Highly Accelerated (10x) Parallel Acquisition for 3D Time-Resolved CE-MRA of the Calves Haider, Clifton No conflicts 106 Quantification of the in vivo kinematics of the erficial femoral artery due to hip and knee flexion using magnetic resonance imaging Choi, Gilwoo No conflicts

107 Comparison of 3D-TRICKS and 3D Bolus Chase MR Angiography for evaluation of infra-popliteal arteries Zhang, Xiaoming No conflicts 108 Comparison of HYPR Stack-of-Stars and HYPR VIPR to TRICKS in Peripheral CE MRA Wu, Yan No conflicts 109 Optimizing Peripheral Contrast-Enhanced MRA using a-priori Knowledge of Bolus Kinetics through the Optimal Choice of Imaging Parameters and Acquisition Time Maki, Jeffrey No conflicts 110 Clinical Experience of HYPR FLOW Wu, YiJing No conflicts 111 7-Tesla Time-Resolved Contrast-Enhanced 3D MRA (TWIST) of the Intracranial Vessels Maderwald, Stefan No conflicts 112 Influence of the injection rate on vessel signal and image quality in first pass imaging with gadofosveset (Vasovist®) Michaely, Henrik Bayer Healthcare/Bayer Schering, Research Grant 113 In Vivo High resolution Magnetic Resonance Spectroscopy of the Adult Zebrafish Brain at 9.4T Kabli, Samira No conflicts 114 Neurochemical profile of hippocampal-specific iron transporter Slc11a2 (DMT-1) knock-out mice Tkac, Ivan No conflicts 115 Metabolic Changes in Rat Frontal Cortex after Injection of Pentylenetetrazole Measured by Proton MR Spectroscopy at 9.4T Yang, Shaolin No conflicts 116 Cerebral activation by fasting results in lactate accumulation in the hypothalamus Violante, Ines No conflicts 117 Preliminary studies of MDMA induced brain hyperthermia using spectroscopic imaging and 1H-[13C]MRS Jiang, Lihong No conflicts 118 Overcoming experimental challenges in the assessment of metabolic fluxes with [1,6-13C-2]glucose in mouse brain Nabuurs, Christine No conflicts 119 NMR Investigations of Acetate Transport and Metabolism in the Rat Brain In Vivo Patel, Anant No conflicts

120 Cerebral Phosphate Metabolite Profiles and their Differentiation in Human, Cat and Rat Brains: A Comparison Study of In Vivo 31P MRS at High Fields Zhu, Xiao-Hong No conflicts 121 In Vivo High Resolution Localized Two Dimensional Magnetic Resonance Spectroscopy in Mouse Brain Braakman, Niels No conflicts 122 Examining Neuro-metabolic Correlations between Resting Rat Brain Activity and Cerebral Metabolite Contents/Metabolic Rates: A 1H/31/P MRS Comparison Study Du, Fei No conflicts 123 Longitudinal evaluation of cartilage degeneration in ACL-injured knees using MR T1rho quantification – A preliminary study Li, Xiaojuan No conflicts 124 The value of pre-contrast T1 measurement for dGEMRIC Li, Wei No conflicts 125 Reproducibility of dGEMRIC in the Human Knee Joint at 1.5 T Multanen, Juhani No conflicts 126 Single Section versus Volumetric analysis of dGEMRIC scans in a Longitudinal Multicenter MultivendorTrial : The A9001140 Study Krishnan, Nitya 127 Comparison of Quantitative Imaging of Cartilage for Osteoarthritis: T2, T1rho, dGEMRIC, and Contrast-Enhanced CT Taylor, Carmen No conflicts 128 Evaluation of Cartilage Repair with T2 and dGEMRIC Up to Two Years After Autologous Chondrocyte Transplantation Mattila, Lauri No conflicts 129 Magnetization Transfer Contrast and T2 relaxation in the evaluation of cartilage repair tissue at 3T MRI Welsch, Goetz No conflicts 130 Effect of Joint Loading on T2 relaxation and dGEMRIC of Knee Cartilage in Marathon Trainers Nieminen, Miika No conflicts 131 Quantitative T2 mapping of knee cartilage: Initial results on the differentiation of healthy and altered articular cartilage of the knee by means of unloading Mamisch, Tallal Siemens, Consulting fee, 132 Cartilage Deformation under Load in a Human Cadaveric Hip Measured with 7.0T qMRI Greaves, Laura No conflicts

133 An Eddy-Current-Compensated Diffusion-Weighting Preparation Based on a Single Spin Echo Finsterbusch, Jürgen No conflicts 134 Single Step Non-Linear Diffusion Tensor Estimation In the Presence of Microscopic and Macroscopic Motion Aksoy, Murat No conflicts 135 Reducing distortions in DW-EPI with a dual-echo blip-reversed sequence Gallichan, Daniel No conflicts 136 Crossing Fibers, Diffractions and Non-Homogeneous Magnetic Field: Correction of Artifacts by Bipolar Gradient Pulses Bar-Shir, Amnon No conflicts 137 Partial-Volume Modelling in Diffusion MRI Smith, Stephen No conflicts 138 Free Water Extraction from Diffusion Images Pasternak, Ofer No conflicts 139 Regional Distribution of Outliers of Diffusion MRI in the Human Brain Walker, Lindsay No conflicts 140 To rotate B or not to rotate B? The importance of reorienting the B-matrix during motion correction of DT-MRI data Leemans, Alexander No conflicts 141 Improved SNR in Diffusion Spectrum Imaging with Statistical Reconstruction Haldar, Justin No conflicts 142 Quality Assessment of DTI-based Muscle Fiber Tracking Heemskerk, Anneriet No conflicts 143 A comparison of matching strategies for RF transmission arrays based on network theory Brunner, David No conflicts 144 A Simplified 16-channel Butler Matrix for Parallel Excitation with the Birdcage Modes at 7T. Alagappan, Vijayanand No conflicts 145 An Extensible Transmit Array System using Vector Modulation and Measurement Stang, Pascal No conflicts 146 General Signal Vector Decoupling for Transmit Arrays Scott, Greig No conflicts

147 Intrinsically decoupled Current CONtrolled Transmit And Receive (2/CONTAR) coil elements for arbitrarily arranged transceive coil arrays. Kirilina, Evgenia No conflicts 148 A Close-Fitting 7 Tesla 8 Channel Transmit/Receive Helmet Array with Dodecahedral Symmetry and B1 Variation Along Z Wiggins, Graham No conflicts 149 Hybrid TEM/Loop Coil Array for Parallel High Field MRI Paska, Jan No conflicts 150 Switchable Short Quadrature Body Coil with Two Axial Uniformity Modes Zhai, Zhiyong No conflicts 151 A Novel 8-Channel Transceive Volume-Array for a 9.4T Animal Scanner Weber, Ewald No conflicts 152 Whole Body Imaging at 7T with a 16 Channel Body Coil and B1 Shimming Vaughan, Thomas Bruker Biospin, Business - product development MR Instruments, Inc., Ownership interest, Board Membership 153 Positive and negative BOLD-signals from blood vessels in monkey visual cortex Goense, Jozien No conflicts 154 Spatiotemporal Dynamics of BOLD and CBV responses at millimeter columnar resolution Kim, Seong-Gi No conflicts 155 Orientation maps in ferret visual cortex measured by multi-slice fMRI Liu, Junjie No conflicts 156 Spatial scale estimation of columnar neuronal activity in cats’ visual cortex based on the analysis of ultra-high-resolution CBV-weighted fMRI Chen, Xu No conflicts 157 Multi-resolution classification analysis of ocular dominance columns obtained from human V1 at 7 Tesla: mechanisms underlying decoding signals Shmuel, Amir No conflicts 158 Layer-Specific Blood-Volume MRI of the Retina Nair, Govind No conflicts 159 High Resolution Functional MRI Imaging of Material-Specific Visual Processing in Thalamic Nuclei Ringe, Wendy No conflicts

160 Functional MRI Mapping of Laminar Structures in Cat Lateral Geniculate Nucleus Zhang, Nanyin No conflicts 161 Visualization of Distinct Functional Cortical Units Using Kernel Principal Component Analysis of fMRI Data Song, Xiaomu No conflicts 162 Pushing the Spatial Resolution of BOLD Imaging, the fMRI Cortical Representation of Rat Digits at 9.4T. Pawela, Christopher No conflicts 163 Magnetic Resonance Diffusion Characteristics of Histologically Defined Prostate Cancer in Humans Xu, Junqian No conflicts 164 Reproducibility of quantitative and semi-quantitative dynamic and intrinsic susceptibility-weighted parameters of the cancerous human prostate gland Alonzi, Roberto No conflicts 165 Correlation of ADC and T2 with cell density in prostate cancer at 3.0T Gibbs, Peter No conflicts 166 The Impact of Intermixed Normal Peripheral Zone elements on the Measurement of Apparent Diffusion Coefficient and T2 in Prostate Cancers Langer, Deanna No conflicts 167 Sensitivity and specificity of functional MRI to map tumour hypoxia in the human prostate gland Alonzi, Roberto No conflicts 168 Assessment of Different Quantification Approaches of DCE-MRI in Prostate Cancer at 3T Jia, Guang No conflicts 169 Functional MR Parameters of Histopathologically Indentified Prostate Tissues Riches, Sophie No conflicts 170 Magnetic Resonance Spectroscopic Imaging and Dynamic Contrast Enhanced Prostate MRI: Correlation with Histopathology Zhang, Bao No conflicts 171 Comparison of transceive endorectal and external surface array coils for prostate imaging at 7 Tesla Metzger, Gregory Philips, Consulting fee, 172 High Resolution Imaging of Arterially Delivered Mesoangioblasts Liu, Min No conflicts

173 MRI Studies of In-vitro Perfused Human Pancreatic Islet Cell Activation. Serai, Suraj No conflicts 174 A dynamic process of macrophage infiltration during tumor progression Hsu, Yi-Hua No conflicts 175 Factors Influencing In Vivo MR Imaging of Transplanted Pancreatic Islets Evgenov, Natalia No conflicts 176 Tracking the Fate of Iron-Labeled Cells: Differentiation between Live and Dead Cells Jirak, Daniel No conflicts 177 Self-refocused spatial-spectral pulse pair for positive contrast imaging of cells labeled with erparamagnetic iron-oxide (SPIO) nanoparticles Balchandani, Priti No conflicts 178 Quantitative Tracking of Magnetically Labeled Breast Cancer Cells in Rat Brain with A Fast T2 Mapping Technique liu, wei Philips, Employment 179 MRI detects in vivo migration of rat's bone marrow derived mesechymal stem cells towards quinolinic acid lesion Shemesh, Noam No conflicts 180 Magnetic targeting of stem cells to a site of vascular injury using an MRI contrast agent Kyrtatos, Panagiotis No conflicts 181 MRI Transverse Relaxation Rate Correlates with Number of Viral Particles Expressing H-Ferritin in the CNS Iordanova, Bistra No conflicts 182 Mapping Middle Cerebral Artery Branch Territories with Vessel Encoded Pseudo-Continuous ASL: Sine/Cosine Tag Modulation and Data Clustering in Tagging Efficiency Space Wong, Eric No conflicts 183 erselective Pseudo-Continuous Arterial Spin Labeling Helle, Michael No conflicts 184 Single artery selective labeling using pseudo-continuous labeling Dai, Weiying No conflicts 185 Selective arterial spin labeling MRI assessment of the contribution of the external carotid artery to brain perfusion in patients with symptomatic internal carotid artery occlusion Hendrikse, Jeroen No conflicts

186 How Long to Tag? Optimal Tag Duration for Arterial Spin Labeling at 1.5T, 3T, and 7T Luh, Wen-Ming No conflicts 187 Can arterial spin labeling detect white matter perfusion? Teeuwisse, Wouter No conflicts 188 Water Exchange Rates in Grey and White Matter Measured by Diffusion-Weighted Perfusion MRI St. Lawrence, Keith No conflicts 189 Rapid Blood T1 Calibration for Arterial Spin Labelling Varela, Marta No conflicts 190 A Comparative Study of Absolute Functional CBF Measurements in Normal Human Brain using PASL MRI and [O-15]water PET Qiu, Maolin No conflicts 191 Is Arterial Spin Labeling Ready for Prime Time? IPreliminary results from the QUASAR Reproducibility Study Petersen, Esben No conflicts 192 Quantitative Cardiac 31P Spectroscopy at 3T: Practical Limitations and Solutions El-Sharkawy, AbdElMonem No conflicts 193 Advances in the ERETIC method for the quantification of in-vivo 1H and 31P spectra Schweizer, Susanne No conflicts 194 Non-parametric Analysis of Hyperpolarized Dynamic 13C Lactate Imaging in a Transgenic Mouse Model of Prostate Cancer Lupo, Janine No conflicts 195 Compressed Sensing for Resolution Enhancement of Hyperpolarized Carbon-13 Flyback 3D-MRSI Hu, Simon No conflicts 196 Combination of Datasets from [213C]Acetate and [1-13C]Glucose Experiments Improve Accuracy of Metabolic Rates Determination in Humans Boumezbeur, F No conflicts 197 Quantitative Tissue Oxygen Measurement in Multiple Organs Using 19F MRI Liu, Siyuan No conflicts 198 Improving the resolution of SPRITE for in vivo 23Na Imaging: A comparison of Conical-SPRITE vs Sectorial-SPRITE Romanzetti, Sandro No conflicts

199 Sodium MRI of the Human Brain Using Projection Acquisition in the Steady-State with Coherent Magnetization (Na-PACMAN) Stobbe, Robert No conflicts 200 Quantifying Sodium in the Lumbar Spine In Vivo at 3T Fenty, Matthew No conflicts 201 Detection of a New Pulmonary Gas-exchange Component for Hyperpolarized Xenon-129 Chang, Yulin No conflicts 202 An Alternative Concept of Non-sequence-interfering Patient Respiration Monitoring Graesslin, Ingmar Philips, Employment 203 Prospective Self-Gating for Simultaneous Compensation of Cardiac and Respiratory Motion Curcic, Jelena No conflicts 204 A New Respiratory Gating Technique for Whole Heart cine MRI. Uribe, Sergio No conflicts 205 Spherical Navigator Echoes Using GRAPPA for Rapid 3D Rigid-body Motion Detection Liu, Junmin No conflicts 206 Real-Time Navigator Processing using Kalman Filtering Spincemaille, Pascal No conflicts 207 Cardiac Gating Free of Interference with Electro-Magnetic Fields at 1.5T, 3.0T and 7.0T Frauenrath, Tobias No conflicts 208 A Novel Technique Used To Detect Swallowing In Volume Selective TSE For Carotid Artery Wall Imaging. Chan, Cheuk No conflicts 209 Prospective Motion Correction via Real-Time Active Marker Tracking: An Image Quality Assessment Ooi, Melvyn No conflicts 210 Velocity-compensated DENSE MRI Zhong, Xiaodong No conflicts 211 Reduction of Flow Artifacts in Balanced SSFP Imaging Using S5FP Derbyshire, J. No conflicts

215 Post-stimulus fMRI Changes in Cerebral Blood Flow, Volume and Oxygenation Following Visual Stimulation and Breath-hold Provide Evidence for the Hemodynamic Response Being Neurotransmitter-mediated Donahue, Manus Philips, Honoraria, 216 Origins of the BOLD Post-Stimulus Undershoot Chen, J. No conflicts 217 The post-stimulation undershoot in BOLD fMRI of human brain is not caused by elevated cerebral blood volume Frahm, Jens No conflicts 218 Differentiating sensitivity of post-stimulus undershoot under diffusion weighting: implication of signal origins Harshbarger, Todd No conflicts 219 Intravascular vs. extravascular contributions to fMRI signal change for visual stimuli and hypercapnia Devlin, Hannah No conflicts 220 Dissociation of CBF responses corresponding to negative BOLD activity Ho, Yi-Ching No conflicts 221 Is the negative BOLD response a gain control mechanism? Wade, Alex No conflicts 222 The negative BOLD effect in the rodent barrel cortex model: Investigation using multimodal imaging and electrophysiology. Kennerley, Aneurin No conflicts 223 A temporal comparison of diffusion-weighted fMRI, NIRS and BOLD responses to visual stimuli in adult humans Kohno, Satoru No conflicts 224 Caffeine's effects on neurovascular coupling Chen, Yufen No conflicts 225 Slice-selective Tunable-flip AdiaBatic Low peak-power Excitation (STABLE) pulse Balchandani, Priti No conflicts 226 Multiband Spectral-Spatial Design for High-Field and Hyperpolarized C-13 Applications Kerr, Adam No conflicts 227 A spiral spectral-spatial RF pulse with rotated variable density k-space trajectory Deng, Weiran No conflicts

228 SAR-Constrained Saturation Pulse Designs Based on B0 and B1 Maps Sung, Kyunghyun No conflicts 229 Correction of RF pulse distortions, with application in radial imaging using SWIFT Moeller, Steen No conflicts 230 The Virtual 180: Application to High Field Fast Spin Echo Imaging Lebel, Robert No conflicts 231 Exponential excitation pulses for improved water content mapping in the presence of background gradients Preibisch, Christine No conflicts 232 Strongly Modulating Pulses: a New Method for Counteracting RF Inhomogeneity at High Fields Boulant, Nicolas No conflicts 233 Accelerated Radiation-Damping for Increased Spin Equilibrium (ARISE): A new method for controlling the recovery of longitudinal magnetization Huang, Susie No conflicts 234 Improved accuracy of variable flip angle T1 measurements using optimal radiofrequency and gradient spoiling Yarnykh, Vasily No conflicts 235 An RF pulse with spoiled sidebands improves the accuracy of T1 measurement in DCE-MRI Ragan, Dustin No conflicts 236 Robust Simultaneous ∆ R2 and ∆ R2* Estimation for Vessel Size Imaging Winkelmann, Stefanie Philips, Employment 237 Orientation Dependence of White Matter T2* Contrast at 7 T : A Direct Demonstration Wiggins, Christopher No conflicts 238 Modified PROPELLER Approach for T2-Mapping of the Abdomen Deng, Jie No conflicts 239 Simultaneous T2- and T1-mapping for cardiac applications Blume, Ulrike No conflicts 240 Gleaning Multi-Component T1 and T2 Information from Steady-State Imaging Data Deoni, Sean No conflicts

241 Volumetric Simultaneous T1, T2, T2* and Proton Density Mapping in One Minute Using Interleaved Inversion Recovery SSFP and Multi Gradient Echo Imaging Stehning, Christian Philips, Employment 242 Quantitative Diffusion, Perfusion and T2 α brain MRI of the α-syntrophin knockout mouse in the resting state Brekken, Christian No conflicts 243 Characterizing white matter damage in rat spinal cord with quantitative MRI and histology Kozlowski, Piotr No conflicts 244 Choline kinase silencing in breast cancer cells results in compensatory upregulation of phosphatidylcholine-specific phospholipase C Glunde, Kristine No conflicts 245 Phosphatidylcholine-specific phospholipase C contributes to the increase of phosphocholine in ovarian cancer cells Iorio, Egidio No conflicts 246 Monitoring the Microenvironmental Effects on Choline Metabolism in Human Breast Cancer Cells Eliyahu, Galit No conflicts 247 Elevated choline kinase protein expression and activity correlate with increased MRS-detected phosphocholine levels in ovarian carcinomas Iorio, Egidio No conflicts 248 Phosphocholine depletion is a non-invasive MRS biomarker for PI3K inhibition in childhood high-grade glioma Al-Saffar, Nada No conflicts 249 Absence of Phosphatidylcholine (PC) in Bile of Cholestatic Patients could be a Potential Risk Factor for Cholangiocarcinoma: A 1H MRS Study Ijare, Omkar No conflicts 250 Characterization of a hepatoma cell line in a novel 3D bioreactor flow system using hyperpolarized 13C MRS Keshari, Kayvan No conflicts 251 Metabolic activity of diseased and healthy prostate cells investigated as lactate formation from hyperpolarized 13C-pyruvate Gisselsson, Anna General Electric, financial port Imagnia AB, Ownership interest , Employment 252 13C Succinate Catabolism in Breast Cancer Cells is Sensitive to Extracellular pH and Glucose and Glutamine Levels Mancuso, Anthony No conflicts

253 Metabolic Biomarkers in Blood Plasma of Tumor Bearing Mice Detected by 1H NMR Spectra Stoyanova, Radka No conflicts 254 Novel Method for In Vitro Evaluation of Amyloid Plaque Binding Contrast Agents In Alzheimer's Disease Marjanska, Malgorzata No conflicts 255 Targeting Alzheimer's plaques with Dysprosium based probes Wadghiri, Youssef No conflicts 256 Micro MR Imaging of Beta-Amyloid Plaques and Co-Registration with Iron Deposition and Histological Analysis in both Human Alzheimer’s Disease and APP/PS1 Transgenic Mice Meadowcroft, Mark No conflicts 257 Correlation Between Neurochemical Changes and Development of Alzheimer’s Plaques with Age Monitored by In Vivo High Resolution Magnetic Resonance Microimaging and Spectroscopy Braakman, Niels No conflicts 258 Assessment of cerebrovascular reactivity as a function of age in a transgenic mouse model of Alzheimer’s Disease displaying significant vascular pathology using acetazolamide. Kranz, Felicitas No conflicts 259 Cerebral perfusion, blood volume, vessel size, and vessel density in the B6.PS2APP mouse model for Alzheimer's disease Weidensteiner, Claudia Hoffman-LaRoche, Employment 260 Diffusion Tensor Imaging (DTI) Reveals Evolving White Matter Abnormalities in Patients with Alzheimer’s Disease Zhang, Jiangyang Philips, Research port, Honoraria, 261 Biphasic Changes of Functional Hippocampal Connectivity Identifies AD Risks Wu, Zhilin No conflicts 262 Hippocampal Atrophy Patterns in Mild Cognitive Impairment and Alzheimer’s Disease Mueller, Susanne No conflicts 263 The Dynamics of Olfactory fMRI BOLD Response Differentiate Early AD and MCI from Healthy Controls DeArment, Lindsi No conflicts 264 Representation of the NIH Stroke Scale with Probabilistic Diffusion Weighted Imaging Lesion Atlas Singleton, Kyle No conflicts 265 Assessing recovery in comatose cardiac arrest patients with diffusion-weighted MRI Wu, Ona No conflicts

266 DTI Derived Metrics Correlate with Immunohistochemistry obtained Matrix Metalloproteinase (MMP-9) Expression in Cellular Fraction of Brain Tuberculoma Gupta, Rakesh No conflicts 267 Voxel-Based DTI Analysis of White Matter Alterations in Parkinson’s Disease Zhan, Wang No conflicts 268 Predictive value of Diffusion Tensor Imaging (DTI) Metrics and In Vivo Proton MR Spectroscopy (PMRS) in the Differential Diagnosis of Cystic Intracranial Mass Lesions Gupta, Rakesh No conflicts 270 Quantitative fiber tracking after perinatal hypoxic-ischemia and neurodevelopmental outcome at 2 years van der Palen, Roel No conflicts 271 Apparent diffusion coefficient of the erior cerebellar peduncle differentiates progressive ranuclear palsy from Parkinson’s disease. Tonon, Caterina No conflicts 272 Evaluation of whole brain and regional DTI parameters on diffuse axonal injury patients in the -acute stage Zhuo, Jiachen No conflicts 273 Peripheral versus central white matter damage in chronic traumatic brain injury :a quantitative tractography study. Newcombe, Virginia No conflicts 274 Highly-loaded holmium microspheres for test dose detection and biodistribution prediction in internal radiation therapy of liver malignancies Seevinck, Peter No conflicts 275 MR Guided Islet Cell Transplantation Woodrum, David Siemens, Consulting fee, 276 X-ray Fusion with MRI for Delivery of Encapsulated Stem Cell Therapeutics Gilson, Wesley Siemens, Employment 277 Monitoring Liver Tumor Embolization in VX2 Rabbits: Four-Dimensional Transcatheter Intraarterial Perfusion (TRIP) MR Imaging Wang, Dingxin No conflicts 278 Imaging of Anatomical Structure and Blood Vessels in Porcine Gastric Wall by MR Endoscope Matsuoka, Yuichiro No conflicts 279 MRI endoscopy at 3T Sathyanarayana, Shashank No conflicts

280 A 5 Degree Of Freedom Haptic System for Transrectal Prostate Biopsy and Tissue Palpation with MR Image Guidance Tse, Zion Tsz Ho No conflicts 281 MRI Compatible Robotic System with Haptic Feedback for RF ablation/Biopsy under continuous MRI. Lister, Kevin No conflicts 282 MRI-compatible Haptics: Feasibility of using optical fiber Bragg grating strain-sensors to detect deflection of needles in an MRI environment Park, Yong-Lae No conflicts 283 2D-real-time MR imaging and simultaneous X-ray-like volume visualization of devices Weiss, Steffen Philips, Employment 284 New Techniques for 3D, High-Resolution, Whole Brain Mapping of Murine Vasculature Pathak, Arvind No conflicts 285 Empirical Estimation of Intra-Cellular Volume Fraction in Mouse Spinal Cord with Q-Space Diffusion MRI Ong, Henry No conflicts 286 Detection of embryonic heart motion in the mouse using self-gated MRI Nieman, Brian No conflicts 287 Determining cellular microstructure of isolated rat hearts using correlated time-dependent diffusion and T2/ relaxation measurements Pavlin, Tina No conflicts 288 Diagnostic impact of T2* MRI imaging for improved ex vivo classification of complicated plaques Spehl, Timo No conflicts 289 High-resolution MRI of Implanted Skin Chambers with Integrated Coils Bock, Michael No conflicts 290 Evaluation and Correction of Noise and Resolution Induced Errors in Quantitative Trabecular Bone μ MRI Li, Charles No conflicts 291 A closer look into "DESIRE" for NMR microscopy Weiger, Markus Bruker Biospin, Employment 292 Investigating spatial variances in MR using molecular information from MALDI imaging mass spectrometry Sinha, Tuhin No conflicts

293 Fully-Integrated MR–Optical Imaging Concept for Pre-Clinical Applications Peter, Joerg No conflicts 294 Incidence of NSF at Two Large Medical Centers Prince, Martin No conflicts 295 The Prevalence of Nephrogenic Systemic Fibrosis in Patients with Renal Failure Who Have Received Gadopentetate Dimeglumine Hope, Thomas No conflicts 296 Preclinical studies to investigate the development of NSF: experiments in renally impaired rats Sieber, Martin Bayer Healthcare/Bayer Schering, Employment 297 Is Chronic Liver Disease an Independent Risk Factor for Nephrogenic Systemic Fibrosis? A Comprehensive Literature Review Mazhar, Sameer No conflicts 298 Prevalence of Nephrogenic Systemic Fibrosis in Patients with Chronic Liver Disease Foster, Zeke No conflicts 299 An Interaction of Gadodiamide with Cu+2/ and Zn+2/ Hornak, Joseph No conflicts 300 Evidence for weak protein binding of commercial extracellular gadolinium contrast agents Caravan, Peter Siemens, Research grant Epix, Consulting fee 301 Long-term retention of Gadolinium in the skin of rodents following the administration of Gadolinium based contrast agents Sieber, Martin Bayer Healthcare/Bayer Schering, Employment 302 Characterization of Renal Masses with Arterial Spin Labeling MRI in Patients with Impaired Renal Function in the Era of Nephrogenic Systemic Fibrosis Pedrosa, Ivan No conflicts 303 Morphological and Functional Characterization of a New Model of Hypoxic-Ischemic Encephalopathy in Neonatal Rat using a Bilateral Carotid Artery Occlusion Recker, Rebecca No conflicts 304 Susceptibility Weighted MRI for Detection and Staging of Angiogenesis After Stroke in Rats Jiang, Quan No conflicts 305 Edge location of sodium accumulation in focal cerebral ischemia in the rat: ADC and 23/Na MRI Yushmanov, Victor No conflicts

306 Imaging Macrophage Infiltration Of Ischemic Tissue Is Not Possible Following Transient Middle Cerebral Artery Occlusion. Farr, Tracy No conflicts 307 Estimates of relative contrast recirculation obtained from perfusion MRI: a potential tool for guiding treatment decision in acute ischemic stroke Wu, Sheng-Ping No conflicts 308 Diagnostic Impact of Aortic MRI at 3Tesla in Patients with Acute Cryptogenic Stroke Harloff, Andreas No conflicts 309 Does local AIF improve prediciton of final infarct? Christensen, Soren No conflicts 310 Prediction of hemorrhagic transformation in acute ischemic stroke: MRI texture analysis versus visual inspection of Gd enhancement Liu, Fang No conflicts 311 BOLD MR Mapping of Cerebrovascular Reactivity in Patients with Arterial Steno-occlusive Disease: Validation by Arterial Spin Labeling MRI Mandell, Daniel 312 Asymmetry and Flow Dynamics in the Vertebrobasilar System as Assessed by Vessel Encoded Arterial Spin Labeling Kansagra, Akash No conflicts 313 Multi-phase Fat-pressed 3D SSFP For Robust Coronary Artery Imaging: Improvements over the single phase technique Fung, Maggie General Electric, Employment 314 128-channel highly-accelerated breath-held 3D coronary MR Imaging Shankaranarayanan, Ajit General Electric, Employment 315 Diagnostic Value of Contrast-Enhanced Whole-heart Coronary MRA at 3.0Tesla Yang, Qi No conflicts 316 Improved Coronary MRA Using Wideband SSFP at 3 Tesla with -millimeter Resolution Lee, Hsu-Lei No conflicts 317 Contrast-Enhanced Whole-heart Coronary MRA with Self-Timing and Respiratory Self-Gating Lai, Peng No conflicts 318 MRI detects increased coronary wall thickness in asymptomatic individuals: The Multi-Ethnic Study of Atherosclerosis (MESA) Macedo, Robson No conflicts

319 MR imaging of the coronary vessel wall: comparison of vessel wall characteristics in patients with coronary artery disease and age-matched healthy controls. Gerretsen, Suzanne No conflicts 320 Evaluating Coronary Atherosclerotic Plaque Enhancement by Contrast-enhanced Navigator-gated 3D-SSFP sequence Li, Tao No conflicts 321 Molecular MRI of Vascular Remodeling in a Swine Model of Coronary Injury using an Elastin-Binding Contrast Agent von Bary, Christian No conflicts 322 Black-Blood T1 Mapping for Quantitative Molecular Coronary Vessel Wall Imaging using Elastine-Binding Contrast Agents Stehning, Christian Philips, Employment 323 gagCEST & NOE: Assessment of Glycosaminoglycan Concentration in Vivo Ling, Wen No conflicts 324 IIn Vivo/I Measurement of 23/Na T2* in Human Articular Cartilage at 3T and 7T Staroswiecki, Ernesto No conflicts 325 T1ρ relaxation time of lateral meniscus and its relationship with T1ρ of adjacent cartilage in knees with acute ACL injuries at 3T Bolbos, Radu No conflicts 326 Detection of Proteoglycan Content in Human Osteoarthritic Cartilage Samples with Magnetic Resonance T1ρ Imaging Cheng, Jonathan No conflicts 327 Local flip angle correction for improved volume T1-quantification in 3D dGEMRIC using the Look-Locker technique Siversson, Carl No conflicts 328 Fast 3D T1 Mapping with Variable Flip Angle Method for dGEMRIC: Preliminary Validation Li, Wei No conflicts 329 Multiparametric MRI Characterization of Degradation in Bovine Nasal Cartilage Lin, Ping-Chang No conflicts 330 Multiparametric characterization of healthy and diseased articular cartilage at 17.6T: Early results Raya, Jose No conflicts 331 Accelerated T2 Mapping of Articular Cartilage Using Iterative HYPR Jacobson, Joshua No conflicts

332 Ultrashort TE Spectroscopic Imaging (UTESI) of the Short T2 Tissues in the Musculoskeletal System Du, Jiang No conflicts 333 Dynamic functional volumetric magnetic resonance k-space inverse imaging of human visual system Lin, Fa-Hsuan No conflicts 334 High Spatial High Temporal Resolution MR-Encephalography using Constraint Reconstruction based on Regularization with Arbitrary Projections (COBRA) Grotz, Thimo No conflicts 335 Quantitative 23-Sodium and 17-Oxygen MR Imaging in Human Brain at 9.4 Tesla Enhanced by Constrained k-Space Reconstruction Atkinson, Ian No conflicts 336 Highly Undersampled 3D Golden Ratio Radial Imaging with Iterative Reconstruction Doneva, Mariya No conflicts 337 Three-Dimensional Compressed Sensing for Dynamic MRI Bilgin, Ali No conflicts 338 Constrained Compressed Sensing for fast 3D Visualization of Active Catheters Schirra, Carsten No conflicts 339 HYPR-Constrained Compressed Sensing Reconstruction for Accelerated Time Resolved Imaging Wu, Huimin No conflicts 340 A comparison of L1 and L2 norms as temporal constraints for reconstruction of undersampled dynamic contrast enhanced cardiac scans with respiratory motion Adluru, Ganesh Siemens, Employment 341 Accelerated Dynamic Imaging by Reconstructing Sparse Differences using Compressed Sensing Fischer, André No conflicts 342 MRI Compressed Sensing via Sparsifying Images Samsonov, Alexey No conflicts 343 The Equivalent Magnetizing Current (EMC) method for biplanar active and passive shim design Sanchez Lopez, Hector No conflicts 344 Optimized Longitudinal and Transverse Gradient Coils with up to Seven Imaging Regions de Bever, Joshua No conflicts

345 Azimuthally Symmetric IBEM Gradient and Shim Coil Design Poole, Michael No conflicts 346 Asymmetric head gradient coil for imaging and spectroscopy at 7T Green, Dan Varian, Employment 347 Epoxy Parameters for High Partial Discharge Inspection Voltages Seeber, Derek General Electric, Employment 348 Experiments in Real-Time MRI with RT-Hawk and Medusa Stang, Pascal No conflicts 349 Evaluation of a combined magnetic resonance (MR)/ultra-wideband (UWB)-Radar technique Thiel, Florian No conflicts 350 Performance and in vivo applications of simultaneous PET/MRI Wehrl, Hans No conflicts 351 Design of a Combined PET and Field-Cycled MRI System for Small Animal Imaging Bindseil, Geron No conflicts 352 Split cylindrical gradient coil for combined PET-MR system Green, Dan Varian, Employment 353 Improved B1/-Mapping for Multi RF Transmit Systems Nehrke, Kay Philips, Employment 354 A matrix approach for mapping array transmit fields in under a minute Brunner, David No conflicts 355 Rapid Slice-Selective B1 Mapping for Transmit SENSE Kerr, Adam No conflicts 356 A Fast 3D B1 Mapping Method at 3T Zhao, Sha No conflicts 357 Whole volume three dimensional B1 mapping in 10 seconds Leinhard, Olof No conflicts 358 Simultaneous B0- and B1-map Acquisition for Fast Localized Shim, Frequency and RF Power Determination in the Heart at 3T Schär, Michael Philips, Employment 359 Simultaneous Fast Quantitation of B1 and T1 Maps at 7 T Using the TESSA Principle Zhong, Kai No conflicts

360 Fast Simultaneous Measurement of the RF Flip Angle and the Longitudinal Relaxation Time for Quantitative MRI Hsu, Jung-Jiin No conflicts 361 B1/ Mapping Using Phase Information Created by Frequency-Modulated Pulses Park, Jang-Yeon No conflicts 362 3D B1+ Mapping with Multi-Slab Catalyzed Steady-State Double-Angle Method Wang, Dingxin No conflicts 363 MR Imaging based detection of glial brain tumors in mice after anti-angiogenic treatment. Hamans, Bob No conflicts 364 A Proof-of-Principle Multiparametric in vivo Study of Tumor Microenvironment using a MRI Compatible PET Insert. Procissi, Daniel No conflicts 365 Why do Ductal Carcinoma in situ Lesions Enhance on Dynamic Contrast Enhanced MRI of the Breast? Using X-Ray Fluorescence and MRI to Track the Spatial Distribution of Gd-DTPA in Murine DCIS. Jansen, Sanaz No conflicts 366 Hypoxia and elevated total choline are associated with ‘stem-like’ cancer cells in breast cancer xenograft in vivo: an MR, SPECT/CT, and optical study Krishnamachary, Balaji No conflicts 367 Correlation between choline concentration (H-MRS) and choline uptake (Cho-PET) and early effect of external radiation therapy on both parameters in an experimental tumor model Rommel, Denis No conflicts 368 In Vivo Measurement of Hypoxia in Brain Tumors by qBOLD MRI Methods Garbow, Joel No conflicts 369 Comparative study of tumor lactate and tumor vasculature in aggressive and indolent prostate cancer animal models by 2D-MR Spectroscopic Imaging and DCE-MRI Yaligar, Jadegoud No conflicts 370 High Spatio-Temporal Resolution pHe Mapping of a Rat Glioma Derived From pH-Dependent Spin-Lattice Relaxivity Zhang, Xiaomeng No conflicts 371 Towards In Vivo Brain Tumor Phenotyping With Proton Csi Pattern Perturbation Simões, Rui No conflicts

372 Imaging the Metastasis of Cancer Cells From a Primary Implant Site Lui, Tracey No conflicts 373 Detecting Age-Related Changes In Resting Cbf Using CASL MRI Asllani, Iris No conflicts 374 Increased Glial Energy Metabolism during Normal Brain Aging assessed by Dynamic 13/C NMR Spectroscopy Boumezbeur, Fawzi No conflicts 375 Alterations of Brain Metabolites during Normal Aging: Correlation with Altered Energy Metabolism Boumezbeur, Fawzi No conflicts 376 Voxel Based Analysis Derived From Fractional Anisotropy Images Of White Matter Atrophy With Aging Pagani, Elisabetta No conflicts 377 Frontal-cortical pathways for working memory: DTI fiber pathway reduction in healthy older jects Li, Zhihao No conflicts 378 Correlation of Fractional Anisotropy in Rhesus Monkeys with Age and Motor Function Hardy, Peter No conflicts 379 Ageing and Fractional Anisotropy: Global and Regional Results Gattu, Ramtilak No conflicts 380 Different T1 relaxation brain ageing patterns over the human lifespan: frontal vs. posterior brain (75 jects) Saito, Naoko No conflicts 381 Alterations of globus pallidus magnetisation transfer ratio, T1/, T2/ in Primary Biliary Cirrhosis patients and controls: relationship with age and autonomic dysfunction Hollingsworth, Kieren No conflicts 382 The impact of cerebrovascular risk factors on brain tissue changes: A MTI study Ropele, Stefan No conflicts 383 Assessment of stroke volume variability using real-time spiral phase contrast Carvalho, Joao No conflicts 384 Real-Time and Cardiac Gated CINE MR Doppler Santos, Juan No conflicts 385 Reference-less flow measurements using refocused SSFP Nielsen, Jon-Fredrik No conflicts

386 Accelerated Phase-Contrast MR Imaging: Comparison of SENSE, k-t BLAST and Doppler Ultrasound for Velocity and Flow Measurements of the Aorta Stadlbauer, Andreas No conflicts 387 Improved Velocity-to-Noise Ratio in Time-resolved 3D Blood Flow Measurements for Cardiac Imaging von Spiczak, Jochen No conflicts 388 MRI Determination of Pulse Wave Velocity in the Carotid Arteries Hardy, Christopher General Electric, Employment 389 Aortic Pulse Wave Velocity Assessed with Velocity-Encoded MRI: Validation with Catheterization and Clinical Applicability Westenberg, Jos No conflicts 390 Hemodynamics and Wall Shear Stress in the Pulmonary Arteries of Hypertension Patients using Phase Contrast MRI Barker, Alex No conflicts 391 Temporal stability of the background velocity error ports automated correction of flow measurements Gatehouse, Peter No conflicts 392 Magnetic Field Monitoring for Improved Phase Contrast Flow Quantification Wiesinger, Florian General Electric, Employment 393 Hyperpolarized 3/He diffusion MRI at two time scales during a single breath hold: Assessment of the lung microstructure in asthmatics with comparison to healthy and COPD jects Wang, Chengbo Siemens, , 394 In vivo Lung Morphometry Identifies Detail Changes of Lung Microstructure with Emphysema Progression Yablonskiy, Dmitriy No conflicts 395 Self-calibrated voxel-wise assessment of ventilation during respiration using dynamic hyperpolarized 3He MRI Santoro, Davide No conflicts 396 Determination of Alveolar Oxygen Partial Pressure in Rat Lung using Spin-Spin Relaxation Times of 3/He and 129/Xe at Low Magnetic Field Strength Kraayvanger, Ryan No conflicts 397 Detection of perfusion-induced susceptibility effect in the lung by hyperpolarized 3He MRI: a co-registration with partial pressure of oxygen Yu, Jiangsheng No conflicts

398 Quantitative Analysis of MCh Induced Ventilation Changes in Mouse Lungs in a Time Series Mistry, Nilesh No conflicts 399 ENaC-mediated effects assessed by proton MRI in a rat model of hypertonic saline-induced hydration of airways Blé, François-Xavier No conflicts 400 Multi-Center Study for Clinical Stage Classification of Smoking-Related COPD: Oxygen-Enhanced MRI vs. Quantitatively Assessed MDCT Ohno, Yoshiharu No conflicts 401 Increased pulmonary capillary permeability in smokers as measured by DCE-MRI Naish, Josephine No conflicts 402 Detecting Brain Activity Using Direct Water Saturation Donahue, Manus Philips, Honoraria 403 Estimation of vascular contribution to DfMRI (Diffusion weighted fMRI) signal. Urayama, Shin-ichi No conflicts 404 Functional MRI in white matter: Experimental evidence at 4-T Mazerolle, Erin No conflicts 405 Neuronal current imaging: sensitivity of magnitude and spatial distribution to changes in current timing Drobnjak, Ivana No conflicts 406 Magnetization “reset” for non-steady-state blood spins in Vascular-Space-Occupancy (VASO) fMRI Lu, Hanzhang No conflicts 407 Combine NIRS and fMRI to investigate hemodynamic response to transient activation and deactivation Tang, Lin No conflicts 408 Functional Mapping of CK and ATPase Metabolic Rate Changes Elevated by Visual Stimulation in Cat Brain Zhu, Xiao-Hong No conflicts 409 Metabolic imprint of EEG slow oscillations as observed by BOLD-fMRI during deep sleep Horovitz, Silvina No conflicts 410 The relationship between fMRI and MEG: Visual contrast response Stevenson, Claire No conflicts 411 An fMRI and MEG Investigation of Repetition pression in the Visual Cortex Vidyasagar, Rishma No conflicts

415 Fast Diffusion Imaging using Undersampled Propeller EPI Engström, Mathias No conflicts 416 Retrospective, reference-less ghosting correction in PROPELLER EPI Nielsen, Jon-Fredrik No conflicts 417 Calibration free distortion correction for propeller EPI Skare, Stefan No conflicts 418 A Method for Removing Off-Resonance Artifact in Turboprop Pipe, James No conflicts 419 Targeted-PROPELLER MRI Deng, Jie No conflicts 420 Abdominal imaging in free-breathing mice using PROPELLER Pandit, Prachi No conflicts 421 Assessment of Concomitant Gradient Blurring in Spiral In-Vivo scans at 1.5 T Sica, Christopher No conflicts 422 Optimization of undersampled variable density spiral trajectories based on incoherence of spatial aliasing Kim, Yoon-Chul No conflicts 423 A fast method for designing time-optimal gradient waveforms for arbitrary k-space trajectories Lustig, Michael No conflicts 424 Variable Density Bunched Phase Encoding Moriguchi, Hisamoto No conflicts 425 Gibbs Tracking: A Novel Approach for the Reconstruction of Neuronal Pathways Kreher, Björn No conflicts 426 Probabilistic diffusion-tensor fiber tractography in a Bayesian framework with an atlas prior Cook, Philip No conflicts 427 Quantitative Validation of MR Tractography using the CoCoMac database Hagmann, Patric No conflicts 428 Combining tractography and coherence measures to identify connectivity within a neural network for reading Welbourne, Stephen No conflicts

429 Quantification of white matter fiber orientation at tumor margins with diffusion tensor invariant gradients Kindlmann, Gordon No conflicts 430 Computing Strings of Average HARDI Models Using Procrustes-Based Fibre Alignment Kezele, Irina No conflicts 431 Software Tool to Generate Complex Structures for Validation of Fibre Tracking Close, Tom No conflicts 432 Visualisation of CSI metabolite concentrations along specific white matter tracts Coward, Hannah No conflicts 433 Using Boy’s Real Projective Plane Immersion for Coloring DT-MRI Slices Demiralp, Cagatay No conflicts 434 Traveling wave MR on a whole-body system Brunner, David No conflicts 435 Non-resonant microstrip (NORM) RF coils: an unconventional RF solution to MR imaging and spectroscopy Zhang, Xiaoliang No conflicts 436 A 6-Element Coil Array for Parallel Imaging in Arbitrary Directions Korn, Matthias No conflicts 437 16-channel microstrip array using 1st and 2nd harmonics for parallel imaging at 7T Wu, Bing No conflicts 438 Tic Tac Toe: Highly-Coupled, Load Insensitive Tx/Rx Array and a Quadrature Coil Without Lumped Capacitors Ibrahim, Tamer No conflicts 439 An 8-Channel Array Adapted for Pediatric Cardiac Imaging Grafendorfer, Thomas No conflicts 440 A 128-channel Helium-3 Phased Array at 3T for Highly Accelerated Parallel Imaging in Hyperpolarized Gas MRI Lee, Ray No conflicts 441 Flexible Microcoils for In-vivo Biliary Imaging Ahmad, Munir No conflicts 442 Coil Geometry Optimization for Better SNR and Decoupling Nascimento, George No conflicts

443 Cryogenic Varactor-Tuned 4-element Array and Cryostat for µ-MRI of Trabecular Bone in the Distal Tibia Wosik, Jarek No conflicts 444 Monitoring non invasively by Contrast enhanced MRI the decrease in tumors interstitial fluid pressure following collagenase treatment Hassid, Yaron No conflicts 445 The Effect of Tumor Proteases on Invasion and Vascularisation Woenne, Eva No conflicts 446 Combination of DCE and DSC MRI: Added value in the study of tumor vascularization Heilmann, Melanie No conflicts 447 Post-radiation change in MRI Dynamic Contrast Enhanced Ktrans did not explain tumor reoxygenation of irradiated naturally-occurring canine tumors. Kraft, Susan No conflicts 448 Novel Insights into Intravenous Bradykinin Analogue-Mediated Vasomodulation from Dynamic Contrast-Enhanced MRI of RG-2 Rodent Malignant Gliomas Sarin, Hemant No conflicts 449 Vessel Size Index MRI: Validation with Micro-CT Angiography Ungersma, Sharon Genentech, Inc., Employment 450 DOCENT- Dynamic Oxygen Challenge Evaluated by NMR T1 and T2* of Tumors Pacheco-Torres, Jesus No conflicts 451 Investigating the influence of physiological variation on the form of the arterial input function in DCE-MRI Little, Ross No conflicts 452 Prediction of Treatment Response in Head and Neck Cancer Using DCE-MRI Kim, Sungheon No conflicts 453 DCE-MRI of Human Brain Tumors Using Gadoteridol and Ferumoxytol Njus, Jeffrey No conflicts 454 A simple two-compartment model that describes Dynamic Contrast-Enhanced MRI signal in the kidney Tofts, Paul No conflicts 455 DCE MRI based perfusion parameters in renal transplants: influence of the choice of the arterial input function. Dujardin, Martine No conflicts

456 Assessment of Renal Function using MR Renography without Aortic Input Information Zhang, Jeff No conflicts 457 Noninvasive Monitoring of Acute Tubular Necrosis Induced by Ischemia/Reperfusion in a Rat Model using 23/Na MRI Atthe, Bharath No conflicts 458 Measurement Precision of Gadolinium Enhanced Magnetic Resonance Nephro-Urography using Rapid 3D Imaging and a Multi-Compartment Kinetic Model Salman, Khalil No conflicts 459 DCE-MRI demonstrates immediate post-perfusion microvascular hyperpermeability in the mouse renal cortex following ischemia induced by renal artery clamping. Knowles, Negar No conflicts 460 Renal tracer kinetics with a reabsorption correction Sourbron, Steven No conflicts 461 MR Elastography of the Kidneys: Preliminary Results Venkatesh, Sudhakar No conflicts 462 Retrospective respiratory triggering for 2D abdominal perfusion MRI Attenberger, Ulrike No conflicts 463 Badaptive 2d centric view ordering for fast abdominal imaging/b Bayram, Ersin General Electric, Employment 464 Simultaneous Acquisition of MR Angiography and Venography (MRAV) Du, Yiping No conflicts 465 PC HYPR Flow: a technique for rapid imaging of contrast dynamics Velikina, Julia No conflicts 466 Conjugate-Gradient HYPR of Intracranial AVMs Jeong, Hyun No conflicts 467 Hybrid-MRA: A New Non-contrast MRA Technique with dual-echo 3D Gradient Echo Sequence in Combination of Time-of-Flight and Flow-Sensitive Black-Blood Kimura, Tokunori No conflicts 468 CE-MRA and MR velocimetry in the determination of hemodynamic forces in longitudinal studies of intracranial aneurysm growth Saloner, David No conflicts 469 Intracranial 4D MRA: Evaluation of Additional View Sharing for Improved Temporal and Isotropic Spatial Resolution at 3.0 T Hadizadeh, Dariusch No conflicts

470 In-vivo visualization and analysis of 3D hemodynamics in cerebral aneurysms with flow-sensitized 4D MR imaging at 3T Meckel, Stephan No conflicts 471 Evaluation of Intracranial Aneurysms with 7T versus 1.5T MR Angiography Moenninghoff, Christoph No conflicts 472 Imaging of lenticulostriate arteries at 7 Tesla Zwanenburg, Jaco No conflicts 473 High resolution intracranial time-of-flight (TOF) MRA at 7T using autocalibrating parallel imaging von Morze, Cornelius No conflicts 474 Dual Transfer of Gene and MR Contrast Agent into Stem-Progenitor Cells for in vivo MR Imaging of Stem Cell-mediated Gene Therapy Qiu, Bensheng No conflicts 475 Hyperpolarized 3/He MRI to Detect Lung Metastases Targeted by Magnetic Nanoparticles Branca, Tamara No conflicts 476 Charged nanoparticles for MRI of the basement membrane Bennett, Kevin No conflicts 477 An MRI Contrast Agent Targeted for Activated Platelets allows Detection of Thrombosis and Thrombolysis in an in vivo Mouse Model von Elverfeldt, Dominik No conflicts 478 MRI-invisible pathology in murine cerebral malaria revealed by a novel contrast agent recognising activated platelet glycoprotein IIb/IIIa receptors Sibson, Nicola No conflicts 479 Novel Single Layer MR-Visible Alginate Microcapsules for Visualization and Immunoprotection of Hepatocytes Link, Thomas No conflicts 480 Lipid-coated silica nanoparticles; a contrast agent platform for multimodality molecular imaging Koole, Rolf No conflicts 481 Improved molecular imaging of angiogenesis by synergistic targeting of liposomal contrast agent to the receptors α ν β3/ integrin and Galectin-1 Kluza, Ewelina No conflicts 482 Urokinase Plasminogen Activator Receptor (uPAR) Targeted Multifunctional Magnetic Nanoparticles for in vivo Molecular MRI of Pancreatic Cancers Mao, Hui No conflicts

483 In vivo and in vitro mapping of the radio frequency magnetic field generated by microsized resonators in a 3T clinical MRI scanner Ciocan, Razvan No conflicts 484 Inverse Consistent Geometric Flow based Nonlinear Registration Driven by Mutual Information Tao, Guozhi No conflicts 485 iMRI Data Repository for Validation of Brain Non-Rigid Registration Algorithms Archip, Neculai No conflicts 486 An Automatic Computational Method for the Measurement of Amyloid Plaque Load in the APP Transgenic Mouse Brain Iordanescu, George No conflicts 487 Improved Accuracy and Smoothed Lipid Content by Maximum A Posteriori Estimation in CHESS Ratio Images Wong, Wilbur No conflicts 488 Quantitative Contrast Enhancement Maps of the Carotid Atherosclerotic Plaque In-vivo: Methodology and Clinical Assessment Balu, Niranjan No conflicts 489 Efficient MRI simulation via integration of the signal equation over triangulated surfaces Antiga, Luca No conflicts 490 Quantitative Magnetization Transfer Imaging Using Balanced SSFP Gloor, Monika No conflicts 491 Optimal Sample Parameter Estimates from Phased Array Coil Data Utilizing Joint Bayesian Analysis Quirk, James No conflicts 492 Computer-Generated Abdominal Phantom for Evaluation of MR Estimation Techniques Graff, Christian No conflicts 493 A flexible software phantom for generating realistic dynamic contrast-enhanced MR images of abdominal tumours. Banerji, Anita No conflicts 494 Diffusion Tensor Imaging of In Vivo Human Kidney at 3 T : Robust anisotropy measurement in the medulla Chandarana, Hersh No conflicts 495 Strategies for Reducing Respiratory Motion Artifacts in Quantitative Renal Perfusion Imaging with Arterial Spin Labeling Robson, Philip No conflicts

496 Initial Experience with RF shimming at 3T using a whole body 8 channel RF system Hajnal, Jo Philips, Grant port 497 Dynamic Contrast Enhanced MRI Evaluation of Crohn's Disease Activity: A Histopathological Correlation Punwani, Shonit No conflicts 498 Diffusion-Weighted Imaging during Acute Unilateral Ureteral Obstruction - Demonstration of the necessity to separate diffusion and microperfusion contributions Binser, Tobias No conflicts 499 Evaluation of acute hepatic ischemia in rats using 23Na and 1H diffusion-weighted MRI Hopewell, Paige No conflicts 500 Characterization of focal renal masses evaluated only with DW imaging and non-enhanced MR sequences Berggruen, senta No conflicts 501 Effect of Field Strength and Software on Apparent Diffusion Coefficient Measurements in Diffusion-Weighted Imaging of the Abdomen at 1.5 and 3 Tesla.B/B Braithwaite, Adam No conflicts 502 ROtated Slab Excitation (ROSE) for Reduced Foldover Artifacts in Coronal 3D Abdominal Imaging Brau, Anja General Electric, Employment 503 MRI monitoring of the influence of US contrast agent destruction for local delivery of a MRI blood pool contrast agent in the rat liver Frulio, Nora No conflicts 504 Pathological Basis of Dirty Appearing White Matter in Multiple Sclerosis: Insights from MRI and Histology Laule, Cornelia No conflicts 505 Addressing the enigma of invisible pathology in MS: a multimodal approach to characterize diffusely abnormal and normal-appearing white matter Seewann, Alexandra No conflicts 506 MRI of Multiple Sclerosis with High Contrast Susceptibility-Weighting and Extreme Resolution T2-Weighting Eissa, Amir No conflicts 507 Phase Imaging of Multiple Sclerosis at 7T Hammond, Kathryn No conflicts 508 In vivo characterization of cortical lesions in multiple sclerosis by 7T MRI Mainero, Caterina No conflicts

509 Indication of oxidative stress in Multiple Sclerosis using proton MR spectroscopic imaging at 7T Srinivasan, Radhika No conflicts 510 High field MRI for lesion characterisation in multiple sclerosis Schmierer, Klaus No conflicts 511 7 Tesla Sodium MRI of patients with Multiple Sclerosis: A preliminary study Madelin, Guillaume No conflicts 512 Magnetization Transfer Ratio Imaging in Multiple Sclerosis – a comparison of 3D balanced steady-state free precession and 2D gradient echo sequences in clinical studies Hirsch, Jochen No conflicts 513 Tract-Based Spatial Statistics shows lower FA in the fornices of early MS patients Roosendaal, Stefan No conflicts 514 In vivo MR imaging of endothelial VCAM-1 expression in a mouse model of both stable and vulnerable atherosclerotic plaque Paulis, Leonie No conflicts 515 Contrast-enhanced MRI of atherosclerosis with collagen targeted CNA35-micelles de Smet, Mariska No conflicts 516 In vivo molecular MRI using an elastin-binding contrast agent investigating carotid artery injury in mice Makowski, Marcus No conflicts 517 MRI of Coronary Vessel Wall Injury in a Swine Model of Coronary Intervention using an Eletrostatically Stabilized VSOP Nanoparticle von Bary, Christian No conflicts 518 Novel nanomedicine for anti-inflammatory therapy of atherosclerosis monitored by multimodality imaging Lobatto, Mark No conflicts 519 Detection of Atherosclerotic Plaque Progression: Correlation of Contrast MRI with PET using 64/Cu-labeled Natriuretic Peptide McCommis, Kyle No conflicts 520 3D SPACE MR imaging of Human Atherosclerotic Femoral Artery at 3.0T Zhang, Zhuoli No conflicts 521 Correlation of 3T-MRI Carotid Artery Wall Volume and B-mode Ultrasound Intima-Media Thickness measurements Duivenvoorden, Raphael No conflicts

522 Spatial Heterogeneity of Carotid Artery Wall Strain Using Displacement-Encoded MRI at 1.5T and 3.0T Lin, Alexander No conflicts 523 Flow-sensitive 4D MRI for the analysis of aortic hemodynamics and wall shear stress: results form healthy volunteers and follow-up in aortic stenosis. Frydrychowicz, Alex No conflicts 524 Seasonal plasticity of the olfactory circuit in songbirds assessed with Iin-vivo/I Manganese Enhanced (MEMRI) De Groof, Geert No conflicts 525 Functional mapping of the auditory pathway in adult mice by manganese-enhanced MRI Watanabe, Takashi No conflicts 526 In vivo Tracing Anatomical Circuitry of the Brains using Gadolinium Wu, Carolyn No conflicts 527 Use of short chain oligo-glycerolipids to improve BBB permeability: application to Managanese-Enhanced MRI (MEMRI) Gozzi, Alessandro No conflicts 528 Overexpression of SOD-2 reduces A & β levels and improves the axonal transport deficits in the Tg2576 Alzheimer model mice Massaad, Cynthia No conflicts 529 Longitudinal Studies of Neonatal Cerebellum Phenotypes Development in Gbx2-CKO Mutant Mice Using MEMRI Szulc, Kamila No conflicts 530 Excitotoxic and physiological stimulations provide similar signal enhancement on manganese-enhanced MRI Gobbo, Oliviero No conflicts 531 Temporal Changes in the T1 and T2 Relaxation Rates (Δ R1 and Δ R2) in the Rat Brain are Consistent with the Tissue-Clearance Rates of Elemental Manganese Chuang, Kai-Hsiang No conflicts 532 Detection of Transient Changes in Photothrombotic Cortical Injury by Manganese-enhanced Magnetic Resonance Imaging Chan, Kevin No conflicts 533 Association between reduction in cerebral blood flow and axonal transport deficits in mouse models of diabetes using MRI. Serrano, Faridis No conflicts 534 Multi-Center MRI Reproducibility of Cancellous Bone Microstructure at the Distal Radius Gomberg, Bryon MicroMRI Inc., Ownership interest, Employment

535 Geodesic Topological Analysis of Trabecular Bone Micro-Architecture of High-Spatial Resolution Magnetic Resonance Images Carballido-Gamio, Julio No conflicts 536 Quantification of bone water in the human tibia Iin vivo/I by ultra-short TE radial MRI at 3T Techawiboonwong, Aranee No conflicts 537 Vertebra bone mineral density reduction is associated with vertebra blood perfusion reduction: dynamic contrast enhanced MRI study in a rat orchiectomy model Wang, Yi No conflicts 538 Quantitative Water and Fat pressed Proton Projection MRI (WASPI) Measurement of Bone Matrix Density Differentiates Normal, Osteoporotic and Osteomalacic Bone Cao, Haihui No conflicts 539 Manganese-Enhanced Magnetic Resonance Microscopy of Mineralization Rates Chesnick, Ingrid No conflicts 540 Bone Susceptibility Quantification: In Vivo Feasibility with MR Source QUantification by Inverting the Dipole field de Rochefort, Ludovic No conflicts 541 MR diffusion measurements are sensitive in detecting the effect of age and loading on the response of intervertebral discs Alkalay, Ron No conflicts 542 New MRI Methods for the Monitoring of the Intervertebral Disc Ablation Saar, Galit No conflicts 543 MR Spectroscopy In Intact and Degenerated Bovine Intervertebral Disc Zuo, Jin No conflicts 544 Brain-Computer-Interface using real-time fMRI: Thought-controlled robot arm Lee, Jong-Hwan No conflicts 545 Parallel real-time fMRI with two connected high-field scanners (3T, 7T) Moench, Tobias No conflicts 546 Effect of Pulsed Magnetic Field on fMRI Processing of Pain Robertson, John Fralex Therapeutics, Ownership interest; Dr. Thomas and Dr. Prato are the founders of Fralex Therapeutics and hold stock in the company. 547 Dexterity and Implicit Learning of Sequential Movements Aznárez-Sanado, Maite No conflicts

548 Neural Activity in Human Auditory and Sensorimotor Cortices Modulated by Passively Varied Divided Attention – an fMRI Study Qiu, Maolin No conflicts 549 High Resolution Functional MRI Imaging of Material-Specific Encoding in the Head, Body and Tail of the Hippocampus Ringe, Wendy No conflicts 550 ASL Perfusion fMRI to Image Psychomotor Vigilance Time-on-Task Effects in the Human Brain Rao, Hengyi No conflicts 551 Using fMRI to explore secondary somatosensory areas in the lateral sulcus of squirrel monkeys Zhang, Na No conflicts 552 Linking genes to brain function: expression of serotonin 5-HT1A receptors in specific neuronal populations results in divergent phMRI responses to the selective agonist 8-OH-DPAT Gozzi, Alessandro No conflicts 553 Behavioral correlates of negative BOLD signal changes in the primary somatosensory cortex Baudewig, Juergen No conflicts 554 Novel Statistical Models and Segmentation Methods for Fiber Bundles in DTI Awate, Suyash No conflicts 555 Temporal Dynamics 4D Level Set Method for Segmentation of MR Renography Images Song, Ting No conflicts 556 Brain MR Image Segmentation by Minimizing Scalable Neighborhood Intensity Fitting Energy: A Multiphase Level Set Approach Li, Chunming No conflicts 557 MRI Measurement of Ischemic Brain Penumbra Using Kohonen’s Multi-Parametric Self-Organizing Map (KMP-SOM) Technique Bagher-Ebadian, Hassan No conflicts 558 Segmentation of colorectal cancer MR images Joshi, Niranjan No conflicts 559 HippoQuant: Combining Geometrical and Intensity Information for 3D Hippocampus Detection in 3D T1-weighted MRI images Belaroussi, Boubakeur No conflicts 560 Identification of Intratumour Low Frequency Microvascular Components via BOLD Signal Fractal Dimension Mapping Wardlaw, Graeme No conflicts

561 An Approach to Prostate Segmentation on MR Images Yang, Zhengyi No conflicts 562 Robustness of Morphologic Features for the Characterization of Mass Lesions in Dynamic, Contrast-Enhanced Breast MR Images Buelow, Thomas Philips, , Employment 563 An automated assessment of White Matter Lesions based on regional FLAIR intensity evaluation Jansen, Jacobus No conflicts 564 Diffusion tensor imaging detects mossy fiber sprouting in rat hippocampus after status epilepticus Laitinen, Teemu No conflicts 565 Quantitative Comparison of Fiber Properties from DTI, HARDI and Light Microscopy Choe, Ann No conflicts 566 Direct correlation between diffusion tensor imaging and electron microscopy of the fornix in humans with temporal lobe epilepsy Concha, Luis No conflicts 567 In-vivo Measurement of the Axon Diameter Distribution in the Rat’s Corpus Callosum Barazany, Daniel No conflicts 568 Recognition of grey matter and parallel versus crossing fibre bundles within white matter using HARDI data and a ervised learning algorithm. Schnell, Susanne No conflicts 569 Q-ball imaging of the spinal cord Cohen-Adad, Julien No conflicts 570 Examining Tumor Microstructure with Temporal Diffusion Spectroscopy Colvin, Daniel No conflicts 571 Changes in Pinnation Angle and Fiber Length of Muscles under Plantar- and Dorsi-flexion and Force Production - In-vivo, DTI based Fiber Tractography in Humans. Sinha, Shantanu No conflicts 572 A Comparison of In Vivo and Ex Vivo Diffusion Tensor Imaging in the Same Patient McNab, Jennifer No conflicts 573 Diffusion Tensor Spectroscopy of Myo-Inositol in Human Brain Ellegood, Jacob No conflicts

574 Four-dimensional MR microscopy of the mouse heart using radial acquisition and liposomal gadolinium contrast agent Bucholz, Elizabeth No conflicts 575 Cardiac Magnetic Resonance Imaging Without General Anesthesia in Mice Berry, Christopher No conflicts 576 A relaxographic analysis of multi-compartmental water exchange in isolated perfused rat hearts Seland, John No conflicts 577 Combined functional MRI and μ PET measurements in a mouse model of cardiac infarction Heijman, Edwin No conflicts 578 Myocardium structural remodeling with relation of infarct location and size in porcine model using DTI Wu, Yin No conflicts 579 Modified Skeletal Myoblast Therapy for Cardiac Failure using AAV SDF1 Thattaliyath, Bijoy No conflicts 580 Spiral Cine DENSE MRI at 7T for Quantification of Regional Function in the Mouse Heart Zhong, Xiaodong No conflicts 581 MR study of postnatal development of left ventricular myocardium structure and function in rats Wu, Yin No conflicts 582 Evaluation of Statin Therapy in a Rabbit Model of Aortic Valve Sclerosis Using High Resolution MRI Hamilton, Amanda No conflicts 583 Regional OEF Determination with the BOLD Effect in Normal and Stenotic Dogs McCommis, Kyle No conflicts 584 NMR Shutter-Speed Discrimination of Malignant and Benign Breast Tumors Using ROI Data Li, Xin No conflicts 585 Effect of the Spatial Resolution of A-priori Data on the Quality of Single-Point Dixon Fat-Water Images Ramsay, Elizabeth No conflicts 586 BOLD Contrast in the Breast at 3T Rakow-Penner, Rebecca No conflicts

587 Multi-frequency Off-resonance Correction and Water/Fat Separation for Spiral Breast Imaging Granlund, Kristin No conflicts 588 3-D Tracking of the Mammary Ductal Tree Using Diffusion Tensor MR Imaging Eyal, Erez No conflicts 589 Can Contrast-Enhanced MRI Be Used to Identify Those Breast Tumors at High-Risk for Disease Recurrence with High Specificity Even Prior to Preoperative Chemotherapy? Li, Ka-Loh No conflicts 590 Prediction of long term breast cancer survival using MR metabolomics Bathen, Tone No conflicts 591 Statistical Metrics to Determine When Water Exchange Should be Incorporated into DCE-MRI Analysis: Simulations and Experimental Breast Cancer Results Yankeelov, Thomas No conflicts 592 Combined 2D MR Spectroscopy and Dynamic Contrast Enhanced MRI for Breast Cancer Detection Lipnick, Scott No conflicts 593 The Interaction of Gadolinium Based MR Contrast Agents with Choline Lenkinski, Robert No conflicts 594 Sensitivity encoded VAPOR-FIDLOVS at 7T: mapping the hidden metabolites. Henning, Anke No conflicts 595 Single-shot proton MR spectroscopic inverse imaging Lin, Fa-Hsuan No conflicts 596 Lactate-discriminating Echo-planar Spectroscopic Imaging at 7 T Bito, Yoshitaka Hitachi, , Employment 597 Diffusion weighted spectroscopy: A novel approach to determine macromolecule resonances at 14T Kunz, Nicolas No conflicts 598 erresolution Parallel Spectroscopic Imaging Otazo, Ricardo No conflicts 599 Fast Spectroscopic Imaging using uniform wideband parallel excitation on 7T Gagoski, Borjan No conflicts

600 Parallel Spectroscopic Imaging Reconstruction with Arbitrary Trajectories using k-Space Sparse Matrices (KSPA) Gu, Meng No conflicts 601 Reduction of acquisition time in magnetic resonance spectroscopic imaging using 3D wavelet encoding method: Comparison to chemical shift imaging. Young, Richard No conflicts 602 Voxel shift and Interpolation for Hadamard-encoded MR images. Fleysher, Lazar No conflicts 603 Spectroscopic imaging with volume selection by unpaired adiabatic π pulses: Theory and application Valette, Julien No conflicts 604 Dynamic BOLD MRI of calf and foot muscles Klarhöfer, Markus No conflicts 605 Hyperemic Flow Heterogeneity in Human Leg Muscle: An MRI Study Using Arterial Spin Labeling Wu, Wen-Chau No conflicts 606 Perfusion Tensor Imaging of Human Skeletal Muscle Lu, Kun No conflicts 607 Mapping functional electrical stimulation in denervated thigh muscles of paraplegic patients with T2 parameter imaging Meyerspeer, Martin No conflicts 608 Implementation of FAST-MRS in mouse permits the rapid assessment of muscle ATP synthesis in-vivo. Befroy, Douglas No conflicts 609 Detection of residual dipolar couplings by 2D MRS techniques in skeletal muscle Velan, S. Sendhil No conflicts 610 Metabolic adaptations in skeletal muscle in the early stage of insulin resistance measured I in vivo by 1H and 31P MRS van den Broek, Nicole No conflicts 611 Mitochondrial ultrasensitivity to ADP explains muscle energetics during recovery from exercise Prompers, Jeanine No conflicts 612 High energy phosphate metabolism in Primary Biliary Cirrhosis (PBC) patients monitored by 31P magnetic resonance spectroscopy: abnormalities in pH handling Hollingsworth, Kieren No conflicts

613 Combined 31P MRSI and MRI shows distinct abnormalities in affected muscles in facioscapulohumeral muscular dystrophy Kan, Hermien No conflicts 614 Electrodynamic constraints on homogeneity and RF power deposition in multiple coil excitations Lattanzi, Riccardo No conflicts 615 Increasing bandwidth of spatially selective transmit SENSE pulses using constrained optimization Brunner, David No conflicts 616 Uniform Wideband Slab Selection with B1+ Mitigation at 7T via Parallel Spectral-Spatial Excitation Setsompop, Kawin No conflicts 617 Dual-band RF Shimming at High-Field with Parallel Excitation Kerr, Adam No conflicts 618 Optimal Control Design of Phase-Relaxed Parallel Transmission RF Pulses for Arbitrary Flip Angles Xu, Dan General Electric, Employment 619 Mode Compression of Transmit and Receive Arrays for Parallel Imaging at 7T Alagappan, Vijayanand No conflicts 620 IIn Vivo B1+ Inhomogeneity Mitigation at 7 Tesla using Sparsity-Enforced Spatially-Tailored Slice-Selective Excitation Pulses Zelinski, Adam No conflicts 621 A Minimum SAR RF Pulse Design Approach for Parallel Tx with Local Hot Spot pression and Exact Fidelity Constraint Graesslin, Ingmar Philips, Employment 622 Single-shot z-shim technique using parallel transmitters for reduced suscpetibility artifacts Deng, Weiran No conflicts 626 Optimal location for phase-based arterial input function measurements near the MCA for DSC-perfusion MRI Bleeker, Egbert No conflicts 627 Delay and Dispersion in DSC Perfusion Derived from a Vascular Tree Model Predicts ASL Measurements Gall, Peter No conflicts 628 Correcting PWI-based CBF measurements for arterial input function partial volume and nonlinear contrast relaxivity: comparison with a xenon CT gold standard Zaharchuk, Greg No conflicts

629 Absolute cerebral blood flow in normal volunteers: Correlation between CT-perfusion and dynamic susceptibility contrast MRI Ziegelitz, Doerthe No conflicts 630 A novel vessel segmentation technique based on clustering of dynamic first-pass MR imaging parameters Emblem, Kyrre No conflicts 631 Study of Injection Duration and Onset Time Uncertainty in Dynamic Contrast Enhanced MRI: A Comparison of a Reference Region Model with a Simple 2-compartment Kety Model Liao, Yeng-Peng No conflicts 632 Incorporating the Effect of Capillary Transit Time in DCE-MRI Pharmacokinetic Analysis Cheng, Hai-Ling No conflicts 633 Correction of the T2* influence on the concentration estimation of T1-weighted DCE-MRI data without measuring T2* Kaul, Michael No conflicts 634 Comparison of Analysis Methods for DCE-MRI Data Via Impact on Sensitivity to Treatment Effect Ashton, Edward No conflicts 635 Validation of a Dual Echo DSC-MRI Approach that Enables the Simultaneous Measurement of Blood Flow, Blood Volume and Ktrans/ Quarles, C. No conflicts 636 Imaging Acute Ischemic Tissue Acidosis using a Relaxation-Compensated multi-slice Amide Proton Transfer (APT) MRI SUN, Phillip No conflicts 637 Simultaneous 19/F and 1/H-CEST technique for improved accuracy and efficiency in quantitative CEST measurements Keupp, Jochen Philips, Employment 638 Correction for Artifacts Induced by B0 and B1 Field Inhomogeneities in Chemical Exchange Saturation Transfer (CEST) MRI SUN, Phillip No conflicts 639 Magnetic Resonance Contrast Based on Relaxation Along a Fictitious Field (RAFF) Liimatainen, Timo No conflicts 640 Activated MR Contrast Agent by A Dual Contrast Technique And Their Application Kato, Yoshinori No conflicts 641 Calculation of Susceptibility Maps from Phase Image Data Schäfer, Andreas No conflicts

642 High Resolution Human Brain Susceptibility Maps Calculated from 7 Tesla MRI Phase Data Shmueli, Karin No conflicts 643 Multiple Orientation Acquisition to Invert Dipole Field for Quantitative Susceptibility Mapping Liu, Tian No conflicts 644 Multi-field behavior of Relaxivity in an Iron-rich environment Ghugre, Nilesh No conflicts 645 Role of anatomic liver compartments in relaxivity-iron relationships Ghugre, Nilesh No conflicts 646 Phase Contrast MRA with Simultaneous Fat-Water Separation Johnson, Kevin No conflicts 647 Generalized ik/i-Space Decomposition for Non-Cartesian Water/Fat Imaging Brodsky, Ethan No conflicts 648 Bipolar Multi-Echo Water-Fat Separation: Phase Correction Using Parallel Imaging Yu, Huanzhou General Electric, Employment 649 Fat/Water Separation Using a Concentric Rings Trajectory Wu, Hochong No conflicts 650 IDEAL with Turbo-PROP Huo, Donglai No conflicts 651 Multi-Echo Tricks Acquisition (META): a high spatio-temporal resolution multi-point Dixon sequence for dynamic contrast enhanced MRI Saranathan, Manojkumar General Electric, Employment 652 IDEAL Water-Fat Decomposition with Multipeak Fat Spectrum Modeling Yu, Huanzhou General Electric, Employment 653 Hierarchical IDEAL – robust water-fat separation at high field by multiresolution field map estimation Tsao, Jeffrey Novartis, Ownership interest, Employment 654 Noise considerations in Water-Fat Separation with Bipolar Multi-echo Sequences Lu, Wenmiao No conflicts 655 Linear phase error correction for improved water and fat separation in the dual-echo Dixon techniques Ma, Jingfei General Electric, Royalty

656 Assessment of Radiation Mediated Gene Therapy via Multi-Modality Imaging Haney, Chad No conflicts 657 In vivo 19/F MRS detection of Carboxypeptidase G2 activity / Jamin, Yann No conflicts 658 Non-invasive Detection of Tumor Cell Death - Comparison between FDG and Hyperpolarized 13C-labelled Pyruvate Witney, Timothy No conflicts 659 Phosphorus MRS effectively monitors lentiviral-mediated gene therapeutic silencing of choline kinase in a human breast cancer xenograft Glunde, Kristine No conflicts 660 Tracking Chemotherapy-Induced Changes in Tumor Antigen Expression in a Pre-Clinical Breast Cancer Model Medarova, Zdravka No conflicts 661 Vessel Size Index MRI with Viable Tumor Analysis for Monitoring Anti-Angiogenic Therapeutics Ungersma, Sharon Genentech, Inc., Employment 662 Time-resolved MRA Assessment of Pulmonary Toxicity in a Rabbit Model of Stereotactic Lung Radiation Therapy: Preliminary Results on the Efficacy of a Radioprotector Mata, Jaime No conflicts 663 DCE-MRI Provides Evidence for Vascular Effects of AMG 386, a First-in-Class Anti-angiogenic Peptibody that Specifically Inhibits Interaction of Angiopoietins-1 and -2 with Tie-2 Hwang, Yuying Amgen, Ownership interest, Employment 664 Using BOLD MRI with Carbogen to Evaluate Tumour Response to Antiangiogenic Therapy Walker-Samuel, Simon No conflicts 665 Diffusion weighted imaging as predictor of therapy response in animal model of Ewing-Sarcoma Reichardt, Wilfried No conflicts 666 In Utero MRI Study of Fetal Baboon Brains at 3T Liu, Feng No conflicts 667 Diffusion Spectrum Imaging (DSI) Tractography of Neonatal Cat Brains Takahashi, Emi No conflicts 668 Framework for comparing mutant mice against a DTI-based normative atlas of mouse brain development Yang, Jinzhong No conflicts

669 Directional diffusion kurtosis analysis of rat brain maturation Cheung, Matthew No conflicts 670 White matter alteration in brain hemisphere contralateral to ligation in neonatal rat model of hypoxic-ischemic injury Lau, Ho-fai No conflicts 671 Correlation of Neuroinflammatory Molecules Quantified from CSF with Fractional Anisotropy in the Neonatal Meningitis Gupta, Rakesh No conflicts 672 Development of Fetus Brain Atlas from Multi-Axial MR Acquisitions Guizard, Nicolas No conflicts 673 DTI study of Effects of Glucocorticoids on White Matter Development Muftuler, L No conflicts 674 Fetal exposure to Bisphenol A alters mitochondrial function Kunz, Nicolas No conflicts 675 Effect of fetal-hypoxemia on neurochemical profile of neonate guinea pigs during development Wang, Wen-Tung No conflicts 676 First Microtesla MRI of the Human Brain Zotev, Vadim No conflicts 677 Ultra-sensitive micron-cantilever detection for MRI Banerjee Snyder, Modhurin No conflicts 678 Active Feedback-Enhanced MRI: Hardware Development and Applicatiosn to Early Tumor Detection Hwang, Dennis No conflicts 679 NMR Experiments using no RF coil: RF-Coilless NMR Zhang, Xiaoliang No conflicts 680 A magnetic field monitoring add-on toolkit based on transmit-receive NMR probes Sipilä, Pekka No conflicts 681 Non-Magnetic Cartesian Feedback Transceivers – A New Approach to MR RF Instrumentation Hoult, David No conflicts 682 Realized Wireless Transceiver for MRI Coil Array Wei, Juan No conflicts

683 Single Optical Fiber Transmission for Multi-channel MRI using FDM Method Shen, Gary No conflicts 684 Development of a Multi-Channel Transmit Extension for a Broadband RF-Electronics and its Evaluation on a 9.4 T Animal Scanner with 8 Transmit Channels Ullmann, Peter Bruker Biospin, Employment 685 Integration of an all port drive TEM transmission line coil with a digital transmit/receive chain Erickson, Matthew No conflicts 686 Astounding reproducibility of cerebral phenylalanine levels as determined by 1/H-MR spectroscopy Kreis, Roland No conflicts 687 In Vivo 1H NMR measurement of glycine in human brain at 7 T at short echo time Gambarota, Giulio No conflicts 688 Detection of Glutathione in Human Brain In Vivo by Yield-Enhanced Double-Quantum Filtering at 3T Choi, Changho No conflicts 689 In-Vivo Lactate Detection Using Selective MQ Coherence Spectroscopy: Signal Enhancement Using Spectral-Selective Binomial RF pulses (SS-SelMQC) Thakur, Sunitha No conflicts 690 Validation of Human Brain Vitamin C Concentration Measured Noninvasively Using Short-Echo Time 1/H MRS at 7 T Versus MEGA-PRESS Edited Spectra Terpstra, Melissa No conflicts 691 ProFit-based Quantitation of Cerebral Metabolites using 2D L-COSY at 3T Frias-Martinez, Enrique No conflicts 692 Normal Brain Metabolic Distributions and Age-Dependent Changes Maudsley, Andrew No conflicts 693 Probing dynamics of human brain metabolites with 1/H MRS by T1 ρ and T2 ρ adiabatic relaxations Mangia, Silvia No conflicts 694 Hahn T2/ Relaxation Times of the Neurochemical Profile at 14.1T in the Iin vivo/I Rat Brain Xin, Lijing No conflicts

695 Pseudo-signal injection via inductive coupling creates a calibration factor for metabolite quantification that is immune to coil loading conditions Marro, Kenneth No conflicts 696 Balanced Left Ventricular Myocardial SSFP-Tagging at 1.5 and 3 Tesla Markl, Michael No conflicts 697 Accelerated 3D Tagging for Quantification of Left Ventricular Dyssynchrony in Patients after Myocardial Infarction Rutz, Andrea No conflicts 698 Inverted Left Ventricular Apical Rotation in Patients eligible for Cardiac Resynchronization Therapy assessed by Tagged MRI Predicts acute Response to Biventricular Pacing Rüssel, Iris No conflicts 699 zHARP with Dumbbells (d-zHARP): Accelerated True 3-D Myocardial Regional Function Quantification and Tracking Abd-Elmoniem, Khaled No conflicts 700 Externally Calibrated ARC Parallel Imaging Reconstruction for DENSE Imaging: Initial Experience Aksit, Pelin General Electric, , Employment 701 Respiratory Triggered DENSE Imaging With Navigator Echoes: Initial Experience Fung, Maggie General Electric, , Employment 702 Strain-Encoded (SENC) MR Imaging with Improved Signal-to-Noise Ratio Using Balanced Steady-State Free Precession Basha, Tamer No conflicts 703 Segmental Left Ventricular Function Depends on Gender and Age: New Findings by High Temporal Resolution Tissue Phase Mapping Foell, Daniela No conflicts 704 Myocardial Acceleration Calculation from Highly Time Resolved Tissue Phase Mapping Staehle, Felix No conflicts 705 Non invasive measurement of the volume-pressure work of the human heart by cardiac MR elastography Elgeti, Thomas No conflicts 706 Hepatic Fat Quantification by Low Flip-angle Multi-echo Gradient-echo MR Imaging: A Clinical Study with Validation with MR Spectroscopy Yokoo, Takeshi No conflicts 707 Quantification of Hepatic Steatosis with MRI: Validation in the ob/ob Mouse at 3T Gard, Catherine No conflicts

708 Rapid T2 and lipid-water imaging of the liver with radial IDEAL GRASE Altbach, Maria No conflicts 709 Correction for Multipeak Fat Spectrum When Estimating T2* in the Presence of Fat Yu, Huanzhou General Electric, Employment 710 Quantification of Hepatic Steatosis with MRI: The Effects of Accurate Fat Spectral Modeling Reeder, Scott General Electric, Consulting fee, 711 Fat Quantification Using SPIO as a Surrogate Marker for Iron Accumulation in the Liver Sugay, Sebastian No conflicts 712 Quantification of the hepatic fatty infiltration and the metabolite concentrations using Magnetic Resonance Spectroscopy and in and out of phase Imaging CAVASSILA, Sophie No conflicts 713 Validation of Hepatic Fat Quantified on 3T MRI via Histopathologic Correlation in Patients with Non-Alcoholic Steatohepatitis Hussain, Hero No conflicts 714 Non-invasive quantification of hepatic steatosis with 3.0 Tesla Magnetic Resonance Spectroscopy in patients undergoing liver resection van Werven, Jochem No conflicts 715 Effects of T1 and T2* Relaxation on Fat Quantification by Gradient Echo Imaging Bydder, Mark General Electric, Employment 716 31/P MRS of human brain tumors at 3T using 1/H – 31/P polarization transfer Wijnen, Jannie No conflicts 717 Multi-exponential Diffusion Imaging: Clinically feasible Multiple B-value Diffusion Imaging for high grade gliomas Khayal, Inas No conflicts 718 The Functional Diffusion Map (fDM) as an Early Imaging Biomarker for High-Grade Glioma: Correlation with Conventional Radiologic Response and Overall Survival Galbán, Craig No conflicts 719 A novel membrane-permeant contrast agent for ultra-sensitive brain tumor detection by MRI Kumar, Mohanraja No conflicts 720 Glioma Detection Maximized through Intracellular and Extracellular MR-guided Optical Fluorescence Tomography Gibbs-Strauss, Summer No conflicts

721 Improved Diffusion MR Fiber Tracking for Neurosurgical Applications Berman, Jeffrey No conflicts 722 Random-walk Based Tractography Simulation for the growth of Brain Tumors Chen, Poe-Jou No conflicts 723 Differentiation of Low-Grade Glioma types Using Mutiparametric MR Data Bian, Wei No conflicts 724 Monitoring Brain Tumor Response to Radiation by Sodum MR Imaging Thulborn, Keith No conflicts 725 Which is best for classifying brain tumours from 1H spectra: Expert interpretation, metabolite ratios, classifiers or the INTERPRET decision-port system? Julià-Sapé, Margarida No conflicts 726 Improving Non-contrast Enhanced SSFP Angiography with Compressed Sensing Çukur, Tolga No conflicts 727 Flow-dependent Arterial and Venous Imaging by Non-Contrast-Enhanced traction Angiography Priest, Andrew No conflicts 728 Quantification of Reactive Hyperemia in the Femoral Artery and Vein by MRI-based Blood Oximetry Langham, Michael No conflicts 729 Interactive Two-Dimensional Fresh Blood Imaging Wong, Pauline No conflicts 730 A Novel Non-contrast MR Angiography Technique using Triggered Non-Selective Refocused SPACE for Improved Spatial Resolution and Speed Xu, Jian No conflicts 731 Noncontrast MRA of Renal Artery using Flow-prep FIESTA for Evaluation of Patients with suspected Renal Tumor: Comparison of Dynamic Contrast MRA Masui, Takayuki General Electric, unspecified relationship 732 STARBURST Peripheral MR Venography Edelman, Robert Siemens, Research port 733 Non-Contrast Enhanced Renal MR Angiography with PC VIPR Johnson, Kevin No conflicts

734 Micro MR angiography of the finger as a potential biomarker in systemic sclerosis Wang, Jinnan No conflicts 735 Carotid Artery Imaging at 7T: SNR Improvements using Anatomically Tailored Surface Coils. Piccirelli, Marco No conflicts 736 CSPAMM Tagging of the Extraocular Muscles during Eye Motion: New Insights. Piccirelli, Marco No conflicts 737 Strain Distribution in the Biceps Femoris Long Head Muscle as Determined by Real-time MRI Tagging Fiorentino, Niccolo No conflicts 738 Ultrashort TE (UTE) imaging of the temporomandibular joint (TMJ) at 3T Chung, Christine No conflicts 739 Ultrashort TE (UTE) Imaging: Application to Magic Angle Study of the Achilles Tendon and Enthesis at 3T Du, Jiang No conflicts 740 Clinical Evaluation of Two- Point Dixon based fat-water separation with Conventional Fat pressed 2D Fast Spin Echo Imaging Stanley, David General Electric, Employment 741 Quantification of the Relaxation Times of Combined CT and MR Contrast Agents for Optimal Imaging at MR Arthrography Handley, Taylor No conflicts 742 3T Skin Imaging Barral, Joëlle No conflicts 743 Partial Weight Bearing Patellofemoral Kinematics Measured With MRI After Total Knee Arthroplasty Carpenter, R. No conflicts 744 Ultrahigh magnetic field imaging of the knee using a transmit/receive array coil Goerke, Ute No conflicts 745 A new Approach for High Resolution MRI of the knee at 3T – Evaluation of a moderately T2-weighted 3D-TSE-fs (SPACE) sequence Notohamiprodjo, Mike No conflicts 746 A Resting State Network in the Basal Ganglia Robinson, Simon No conflicts

747 Spontaneous activity in the visual cortex persists during visual stimulation: a 7T study Bianciardi, Marta No conflicts 748 Language lateralization is correlated with resting-state connectivity within the inferior frontal gyri D'Andrea, Jolyn No conflicts 749 Investigating Motor Plasticity using Resting State fMRI and SEM Ma, Liangsuo No conflicts 750 Spatial extent of task-induced fMRI-BOLD response after hemodynamic scaling using resting state fluctuations Kannurpatti, Sridhar No conflicts 751 Caffeine reduces resting-state functional connectivity in the motor cortex Rack-Gomer, Anna No conflicts 752 Comparison of Spontaneous Electrophysiological and fMRI Fluctuations during Rest in Rat Brain Cortex Kim, Young No conflicts 753 Electrophysiological Investigation of the Basis of the Resting-State fMRI Signal Lu, Hanbing No conflicts 754 Effect of Propofol on Thalamocortical Connection: a high-field MR study of Functional Connectivity on Rats Tu, Ye No conflicts 755 Tightly Coupled Spontaneous EEG and CBF Signals in the Anesthetized Rat Brain Liu, Xiao No conflicts 756 Parallel Imaging Method for Split-Blade PROPELLER DWI Huo, Donglai No conflicts 757 GRAPPA-accelerated Readout-Segmented EPI for High Resolution Diffusion Imaging Holdsworth, Samantha No conflicts 758 High-resolution Diffusion Tensor Imaging at 3T with Radial-FSE Sarlls, Joelle No conflicts 759 A Navigated non-CPMG Turbo Spin Echo Pulse Sequence for High Resolution Diffusion Imaging Ye, Yongquan No conflicts

760 High-Resolution Axial DWI of the Spinal Cord with Reduced-FOV Single-Shot EPI Saritas, Emine No conflicts 761 Parallel Line Scan Diffusion Imaging Chu, Renxin No conflicts 762 Diffusion at Short Time Scales: q-space Imaging with Chirped Gradient Waveforms Kiruluta, Andrew No conflicts 763 Observation of microscopic diffusion anisotropy in the spinal cord using double-pulsed gradient spin echo MRI Komlosh, Michal No conflicts 764 Double wave vector diffusion weighting in the human corticospinal tract in vivo Koch, Martin No conflicts 765 Magnetization Transfer Prepared Diffusion Tensor Imaging Avram, Alexandru No conflicts 766 An international, multi-institutional trial of DCE-MRI in children treated for osteosarcoma Reddick, Wilburn No conflicts 767 Dynamic Contrast Enhanced MRI as A Predictor of Long Term Outcome in Pediatric Bone Tumors/B Koutcher, Jason No conflicts 768 Treatment Response Predictor Using 31/P MRS for CHOP and R-CHOP Therapy in Diffuse Large B-Cell Lymphoma Arias-Mendoza, Fernando No conflicts 769 Prediction of response to chemo/radiation therapy of squamous cell carcinomas of the head and neck by 1/H MRS studies of choline Kim, Sungheon No conflicts 770 Predicting Final Pathological Response to Neoadjuvant Chemotherapy in Breast Cancer Using Quantitative MR Spectroscopy Using Internal Reference Method at 1.5T Baek, Hyeon-Man No conflicts 771 Variation of Breast Vascular Maps at Dynamic Contrast-Enhanced MR Imaging before and after Neoadjuvant Chemotherapy of Locally Advanced Breast Cancer. Martincich, Laura No conflicts 772 Dynamic contrast enhanced MRI of solid tumors and healthy tissue during treatment with NGR-TNF, a novel vascular targeting agent van Laarhoven, Hanneke No conflicts

773 DCE-MRI demonstration of antivascular effects of combretastatin A4 phosphate (CA4P) given in combination with bevacizumab to human jects with advanced solid tumours Padhani, Anwar No conflicts 774 MR perfusions imaging of anti angiogenic (bevacizumab) treatment in patients with recurrent high grade gliomas Hou, Bob No conflicts 775 Apparent diffusion coefficients show good reproducibility but heterogeneous change in response to treatment with combrestation A4 phosphate (CA4P) and bevacizumab in patients with solid abdominal and pelvic tumours Koh, Dow-Mu No conflicts 776 Enhanced sensitivity for multidimensional high-resolution magic-angle-spinning 1H-MR spectroscopy Andronesi, Ovidiu No conflicts 777 Downfield Spectra at Ultrahigh Field Henning, Anke No conflicts 778 Lactate Metabolism in Human Brain Measured by Dynamic 13/C MRS Boumezbeur, Fawzi No conflicts 779 Measuring NAA synthesis Iin vivo/I using proton MRS Xu, Su No conflicts 780 Efficient 1/H to 31/P polarization transfer in the human brain on a clinical 3T MR system with a single RF transmit channel Klomp, Dennis No conflicts 781 Ultrafast 2D spectroscopy for in vivo applications on a 7T whole body scanner Panek, Rafal No conflicts 782 Age dependence of the downfield region of cerebral 1/H MR spectra Kreis, Roland No conflicts 783 Safety Evaluation for 1/H Decoupled 13/C Spectroscopy at 3T in Human Frontal Lobe: SAR Analysis Using Numerical Simulations Li, Shizhe No conflicts 784 NMR Measurement of VTCA/ Correlates with Enzymatic Activity along the TCA Cycle as measured by Histochemistry in the Primate Brain Boumezbeur, Fawzi No conflicts 785 Two-echo multiple quantum chemical shift imaging of ascorbic acid (vitamin C) in the human brain Iin vivo at 3 T Choi, In-Young No conflicts

786 Image Reconstruction from Ambiguous PatLoc-Encoded MR Data Schultz, Gerrit No conflicts 787 Off-resonance effects in non-Cartesian parallel imaging Chen, Weitian No conflicts 788 Fast, Mathematically Exact k-Space Sample Density Compensation for Rotationally Symmetric Interleaved Trajectories, and the SNR-Optimized Reconstruction from non-Cartesian Samples Mitsouras, Dimitris No conflicts 789 Improved image reconstruction for partial Fourier gradient-echo EPI Chen, Nan-kuei Glaxo SmithKline, Research support 790 Magnetic Field Monitored Autofocus Deblurring for Improved Non-Cartesian Imaging Wiesinger, Florian General Electric, Employment 791 Fast conjugate phase image reconstruction based on a Chebyshev approximation to correct for B0 field inhomogeneity and concomitant gradients Chen, Weitian No conflicts 792 Improved Time Series Reconstruction for Dynamic MRI Sümbül, Uygar No conflicts 793 Optimizing k-t BLAST/SENSE using FOCUSS and RIGR Jung, Hong No conflicts 794 Generalized Reconstruction by Inversion of Coupled Systems (GRICS) applied to free-breathing MRI Odille, Freddy No conflicts 795 High-resolution pulmonary perfusion imaging in rodents using a spatiotemporal model Schmitter, Sarah No conflicts 796 Thermosensitive Polymer-modified Liposome as a Multimodal and Multifunctional Carrier for MRI and Optical Imaging: Tumor Detection, Visualization of Triggered Drug Release, and Chemotherapy Aoki, Ichio No conflicts 797 Trifluoromisonidazole (TFMISO) as Imaging Agent of Hypoxia in Solid Tumors - An IIn Vivo/I 19/F MR Study Ackerstaff, Ellen No conflicts 798 MRI-guided targeting of magnetic nanoparticles in an orthotopic 9L gliosarcoma brain tumor model Chertok, Beata No conflicts

799 MR Molecular Imaging of Neovasculature May Predict Response to Antiangiogenic Therapy in Animal Cancer Models Schmieder, Anne Kereos, Ownership interest Philips, Employment 800 In vivo intracellular pO2/ measurements of perfluorocarbon labeled 9L glioma cells Kadayakkara, Deepak No conflicts 801 MR-visualization of tumors in mice by Dy-loaded Liposomes as T2*-susceptibility agents. Evidence for a Macrophage mediated detection Aime, Silvio Bracco, Consulting fee, 802 19/F MRS allows quantitative evaluation of anti-angiogenic therapy delivered with targeted perfluorocarbon nanoparticles Waters, Emily No conflicts 803 Correspondence of Magnetic Resonance Molecular Imaging to Quantitative Determination of E- and P-Selectin Expression in Acute Stroke Jin, Albert No conflicts 804 Manganese guided cellular MRI of human embryonic stem cell viability Yamada, Mayumi No conflicts 805 Single cell level detection of Gadolinium-labeled stem cells using a clinical 3.0T MRI scanner Bernsen, Monique No conflicts 806 In vivo tracking of mesenchymal stem cells in the injured mouse spinal cord. Gonzalez-Lara, Laura No conflicts 807 Use of an OVS-FAIR based ASL Technique for High Spatial Resolution Mouse Cervical Spinal Cord Blood Flow (SCBF) Mapping Duhamel, Guillaume No conflicts 808 The First in vivo Mouse Proton and Sodium MR Imaging at 21 T Schepkin, Victor No conflicts 809 Phase Imaging of the Iin vivo Rat brain at 14.1 Tesla Marques, José No conflicts 810 Virtual Mapping of Cyto-architectonic Distinct Structures with MRI Barazany, Daniel No conflicts 811 Magnetization-Prepared Segmented FLASH Sequences for High-Field Anatomical Brain Imaging in Animals Bock, Nicholas No conflicts

812 In Vivo Visualization of Cerebro-microvasculature using 3D ΔR2-Based Microscopic MR Angiography (3D mMRA) Lin, Chien-Yuan No conflicts 813 Decreased mean diffusivity and changes in proton spectra in the brain of aged rats with learning deficits Vorisek, Ivan No conflicts 814 MRI can detect brain shape changes in mice caused by five days of learning Lerch, Jason No conflicts 815 Evidences of Learning and Memory Related Brain Plasticity from Diffusion Tensor Imaging in the Rat Blumenfeld-Katzir, Tamar No conflicts 816 Free Breathing and Breath-held High Temporal Resolution ( 6 ms) Cardiac cine Steady State Free Precession (SSFP) imaging for Estimation of Diastolic Function Krishnamurthy, Ramkumar No conflicts 817 Real-time assessment of right and left ventricular volumes and function in patients with congenital heart disease using high spatio-temporal resolution radial k-t SENSE. Muthurangu, VIvek No conflicts 818 Real-Time M-Mode MRI Monitoring of Regional Wall Thickening Maier, Corinna Siemens, Unspecified relationship 819 High resolution retrospective reconstruction from real-time acquired cine MR images Kellman, Peter No conflicts 820 Vector map visualisation of phase contrast images demonstrates disruption of intra-atrial vortices in newborn infants Groves, Alan No conflicts 821 Contrast-Agent Concentration Quantification during First-Pass MRA using Susceptibility-Induced Magnetic Field Shifts de Rochefort, Ludovic No conflicts 822 Observing the settling of blood in the ine resting condition in the peripheral vascular system using SWI Haacke, Ewart No conflicts 823 Multi-echo Dixon Fat and Water Separation Method for Detecting Fibro-fatty Infiltration in the Myocardium Kellman, Peter No conflicts 824 Black-Blood Imaging of the Human Heart Using Rapid STEAM MRI Karaus, Alexander No conflicts

825 Isotropic high-resolution 3D MRI of carotid arterial wall with imporved blood pression using motion-sensitized dephasing SPACE Fan, Zhaoyang No conflicts 829 High Resolution 2D Imaging without Gradients with Accelerated TRASE Sharp, Jonathan No conflicts 830 Non-Fourier Imaging and Fast B0 Mapping with Linearly Ramped Gradients Sacolick, Laura No conflicts 831 High Speed MR Elastography Using SEA Imaging Bosshard, John No conflicts 832 Multiple Repetition Time Balanced SSFP for Improved Spectral Response Çukur, Tolga No conflicts 833 On the use of steady-state equations to estimate signal intensities in 2D TrueFISP imaging Coolen, Bram No conflicts 834 Analysis of eddy-current artifacts in interleaved balanced SSFP Nielsen, Jon-Fredrik No conflicts 835 Improved shim method for balanced SSFP Lee, Jongho No conflicts 836 High spatial resolution, volume selective 3D FSE imaging Saranathan, Manojkumar General Electric, Employment 837 Flexible and Efficient View Ordering for 3D Sequences with Periodic Signal Modulation Busse, Reed General Electric, Employment 838 Towards Artifact-free MRI near Metallic Implants Lu, Wenmiao No conflicts 839 The Structural Core of Human Cerebral Cortex and its relation to the brain’s default network Hagmann, Patric No conflicts 840 Revealing the topological architecture of human cortical anatomical network by DTI tractography Gong, Gaolang No conflicts 841 Rat brain connectivities after stroke: combined application of diffusion tensor MRI (DTI), manganese enhanced MRI (MEMRI) and functional MRI (fMRI) Bogaert, Aurore No conflicts

842 Localization of Cognitive Function in Rats with Magnetic Resonance Imaging Blumenfeld-Katzir, Tamar No conflicts 843 Brain Localization of Cognitive Domains with Diffusion MRI Sasson, Efrat No conflicts 844 In vivo Diffusion Spectrum imaging disentangles white and gray matter connectivity in the human cerebellum Granziera, Cristina No conflicts 845 Segmentation of Sensory Pathways in Human Trigeminal Ganglion and Brain Stem Upadhyay, Jaymin No conflicts 846 Fiber Tracking of Cervical Spinal Cord and Nerves Benner, Thomas Bayer Healthcare/Bayer Schering, Consulting fee, 847 Building an Atlas of the cortical White Matter: Identification and Assignment of Common Anatomical Structures Oishi, Kenichi Philips, research port, Honoraria, 848 Implicit Reference-Based Group Registration of Diffusion Tensor Imaging Geng, Xiujuan No conflicts 849 Caffeine does not affect regional vascular reactivity to CO2 Chen, Yufen No conflicts 850 Negative BOLD signal under 6% hypercapnia reflects solely oxygen extraction from the blood Zappe, Anne-Catherin No conflicts 851 Validation of Oxygen Extraction Fraction Measurement by qBOLD Technique He, Xiang No conflicts 852 Non-invasive quantification of venous oxygenation and cerebral metabolic rate of oxygen in humans Xu, Feng No conflicts 853 Estimation of the regional cerebral metabolic rate of oxygen consumption with MRI during the first 60 seconds of 17/O2/ inhalation in swine Mellon, Eric No conflicts 854 The Relation between BOLD amplitude and Baseline Cerebral Blood Flow Depends on the Analysis Scale Liau, Joy No conflicts

855 Normalization of fMRI signal with basal physiologic state improves sensitivity in differentiating ject groups Lu, Hanzhang No conflicts 856 Reproducibility of BOLD signal change induced by breath holding Magon, Stefano No conflicts 857 Hypercapnia-Based Calibration Techniques for Measurement of Cerebral Oxygen Metabolism with MRI Drescher, Knut No conflicts 858 Measuring the Effect of Hyperoxia and Hypercapnia on R2* and the Balanced SSFP Signal at 3T Winkelmann, Stefanie Philips, , Employment 859 Metabolic profiling of changes in the transition from Pre-invasive to Invasive Cervical Cancer using Magic Angle Spinning Magnetic Resonance Spectroscopy of intact tissues De Silva, Sonali No conflicts 860 Quantitative Metabolic Profiling of Second and Third Trimester Human Amniotic Fluid via High-Resolution MR Spectroscopy: Analysis for Biomarkers of Fetal Maturation Cohn, Brad No conflicts 861 HR-MAS Spectroscopy of Human Testicular Biopsy Tissue Demonstrates Phosphocholine as a Biomarker of Male Fertility Iman, Rahwa No conflicts 862 Metabolomics-Based Viability Assessment of Cystic Echinococcosis Using High-Field 1H-MRS of Biopsies Hull, William Bruker Biospin, Consulting fee, 863 Identification of amide protons of GSH in MR spectra of tumor cells Grande, Sveva No conflicts 864 1/H MRS of Sputum for the Non-invasive Diagnosis of Lung Cancer Bezabeh, Tedros No conflicts 865 Temperature effect on the HRMAS spectra of human brain tumour biopsies, their pattern recognition analysis and their post-HRMAS histopathology Valverde-Saubí, Daniel No conflicts 866 Abdominal fat measurement: MRS vs. MRI Cui, Min-Hui No conflicts 867 What happens after two years of lifestyle intervention? Changes in different adipose tissue compartments assessed by MRI and MRS Machann, Jürgen No conflicts

868 Understanding Ethnic Differences in Body Adiposity in the Newborn Vasu, Vimal No conflicts 869 Liver and muscle lipid stores and their association with abdominal fat distribution in healthy elderly individuals Sleigh, Alison No conflicts 870 A Comparison of Hepatic Lipid and Glycogen Levels in Type II Diabetics using 1/H and 13/C MRS Stephenson, Mary No conflicts 871 Abnormal Exercise Function in Adolescents with Type 2 Diabetes Correlates Negatively with Soleus Muscle IMCL As Measured by 1H MRS Brown, Mark No conflicts 872 Insulin-stimulated mitochondrial ATP synthesis is impaired in rat muscle by fat-enriched diet Yerby, Brittany Novartis, Ownership interest, Employment 873 Impact on basal and maximal ATP turnover of structured physical activity counselling in type 2 diabetes: a 31/P MRS study Hollingsworth, Kieren No conflicts 874 Manganese enhanced MRI detects pancreatic beta cell function Iin vivo/I Antkowiak, Patrick No conflicts 875 IBFuel Metabolism During Exercise in Eu- and Hyperglycemia in jects with Type 1 Diabetes Mellitus/B/I Ith, Michael No conflicts 876 The Molecular Basis for Gray and White Matter Contrast in Phase Imaging Zhong, Kai No conflicts 877 Using Field Simulations to Understand Susceptibility Related Phase Contrast in High Field Gradient Echo Images Schäfer, Andreas No conflicts 878 Optimization of Phase Contrast in Susceptibility Weighted Imaging at 7T Ge, Yulin No conflicts 879 Visualization of the thalamic nuclei at high spatial resolution and high contrast with susceptibility weighted phase imaging Rauscher, Alexander No conflicts 880 Delineation of the thalamic nucleus (STN) on high-resolution maps of R2* Helms, Gunther No conflicts

881 High resolution R2/* maps reveal laminar structure of human visual cortex Iin vivo./I Fukunaga, Masaki No conflicts 882 Post-mortem MRI of Human Brain Hemispheres: Effects of Formaldehyde Fixation on T2 Relaxation Dawe, Robert No conflicts 883 Magnetisation transfer effects in an IR-TSE study of cortical layers in the area V1 Oros-Peusquens, Ana-Maria No conflicts 885 Iron as a source of laminar contrast in MRI of human cerebral cortex Li, Tie-Qiang No conflicts 886 Use of hyperpolarized 13C mr to monitor cardiac metabolism in vivo in type 1 diabetes Schroeder, Marie General Electric, Grant Funding 887 NMR Detection of 13/CO2/ and [13/C]Bicarbonate is Sensitive to the Duration of Reperfusion after Brief Myocardial Ischemia Merritt, Matthew No conflicts 888 Serial Hyperpolarized 13/C 3D-MRSI Following Therapy in a Mouse Model of Prostate Cancer Chen, Albert No conflicts 889 Imaging pH Iin vivo using hyperpolarized 13C-labeled bicarbonate Gallagher, Ferdia General Electric, Provided research equipment 890 Signal Enhancement in Low-Dose Hyperpolarized 13C Imaging using Multi-Slice FSEPSI Sequence Yen, Yi-Fen No conflicts 891 How Does Dose of Hyperpolarized 13C1-Pyruvate Affect Metabolic Results in Dog Prostate? Zierhut, Matthew No conflicts 892 Acetyl-CoA and acetyl-carnitine show organ specific distribution in mice after injection of DNP hyperpolarized 13/C1/-acetate Rose Jensen, Pernille General Electric, Financial port Imagnia AB, Ownership interest, Employment 893 Imaging Cancer Gene Therapy using 13/C Hyperpolarised MR Technology Jamin, Yann No conflicts 894 Therapeutic target metabolism observed using hyperpolarized 15/N choline Gabellieri, Cristina No conflicts

895 Hyperpolarized 3He MRI Apparent Diffusion Coefficients to derive Non-invasive Lung Pressure-volume Curves Evans, Andrea No conflicts 896 Permanent Non-invasive Device Safety Monitoring for Clinical MRI Krueger, Sascha Philips, Employment 897 An Optically-Coupled System for Quantitative Monitoring of MRI-Induced RF Currents into Long Conductors Zanchi, Marta No conflicts 898 Monitoring Induced Currents on Long Conductive Structures During MRI Venook, Ross No conflicts 899 Measuring RF-Induced Currents inside Implants: Impact of Device Configuration on MRI Safety of Cardiac Pacemaker Leads Nordbeck, Peter No conflicts 900 The Effect of Lead Length on Lead Tip Heating in Orphan Leads verses Leads Connected to Pacemakers at 1.5T Langman, Deborah No conflicts 901 Clinical Trial to Evaluate Pacemaker Safety and Efficacy in MRI Environment: Device and Study Design Kanal, Emanual Medtronics, Consulting fee, 902 A combined approach to assessing safety of depth electrodes and microwires at 3 Tesla Strick, Debra No conflicts 903 Experimental and numerical determination of SAR and temperature distribution of a human endorectal coil for MR imaging of the prostate at 7T Bitz, Andreas No conflicts 904 Whole shaft visibility for polymer-based active iMRI catheters using hybrid braided tubes Kocaturk, Ozgur No conflicts 905 Preclinical Evaluation of a Novel Fiber Compound MR Guide Wire Kraemer, Nils No conflicts

Toronto!ISMRM 16th Scientific Meeting & Exhibition • SMRT 17th Scientific Annual Meeting • 3-9 MAY 2008

Continuing Education Credit

To Receive Credit: If you wish to receive credit and/or a credit certificate,you must:

1. Complete and submit evaluation forms online. (Evaluation is entirely online; there are no paper forms.)

2. Complete the CE LOG section on the evaluation form• Indicate your primary professional activity (physician, other)

• Enter your name and Registration ID number (at top of your badge)

To be entered in a drawing for a year 2009 membership please submit completed meeting evaluation forms.

United States: The International Society for Magnetic Resonance in Medicine designates this educational activity for a maximum of 55 AMA PRA Category 1 CreditsTM. Physicians should only claim credit commensurate with the extent of their participation in the activity.

United Kingdom: Royal College of Radiologists has approved this meeting for up to 55 Category 1 (external) CPD credits.

European Union: The ISMRM 2008 Annual Meeting is accredited by the European Accreditation Council for Continuing Medical Education (EACCME) to provide the following CME activity for medical specialists. The EACCME is an institution of the European Union of Medical Specialists (UEMS), http://www.uems.net.

The ISMRM 2008 Annual Meeting is designated for up to 39 hours of European external CME credits. Each medical specialist should claim only those hours of credit that he/she actually spent in the educational activity.

EACCME credits are recognized by the American Medical Association towards the Physician’s Recognition Award (PRA). To convert EACCME credit to AMA PRA category 1 credit, contact the AMA.

Accreditation for Medical Physicists (Canada and USA) This activity is approved to grant Medical Physics Continuing Education Credit (MPCEC) by the Commission on Accreditation of Medical Physics Education Programs (CAMPEP). To receive CAMPEP credit you must submit completed program evaluations at the meeting website AND a Medical Physics Participant Credit Request (green form). These forms are available at the registration desk, and may be deposited in the white deposit box there. Only one green form is needed for each attendee who requests CAMPEP credit.

Certificates: After the online meeting evaluation page is closed on 23 May, attendees who submitted evaluations can come to the website and log in to print their own credit certificates. There will not be a general posting of certificates from the ISMRM office.

Accreditation The International Society for Magnetic Resonance in Medicine is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

Meeting Evaluation Online Only (There are no paper forms.)Enter evaluations at the meeting website. While in the convention center, use one of the free computer stations on the 700 level, or in the Internet cafe, or your own com-puter in wireless areas. Outside the convention center you can access the website at any time with your own computer. The online evaluation pages will be available for two weeks after the meeting. There is a separate form for each weekend course, plus a form for each day Monday through Friday. Please use the link from the main meet-ing page (http://www.ismrm.org/08), then click on the forms for whichever weekend courses or days of the week you attended. Log-in will be necessary.

CREDITS AVAILABLE:

Saturday and Sunday Courses Credits

MR Engineering: Saturday 6.5

MR Engineering: Sunday 4

Saturday Courses Credits

Advanced Topics in Diffusion & Perfusion: 7.25

Advanced Topics in Analysis of Structural & Functional MRI Data: 6.75

Advanced Brain Imaging: 7

MR Physics for Physicists: 7

Body MRI by the Experts: 7

Clinical MRI: From Physical Principles to Practical Protocols: 6.75

Probing Cancer with MR I: Molecular Pathways to Experimental Models: 5.75

Sunday Courses Credits

Cardiovascular MRI – Basic Techniques and Applications: 6.5

Cancer MRS: Clinical and Research Applications: 6.5

Imaging Strategies: 7

Molecular Imaging: 7

Translating Physics to the Clinic: Diffusion, Perfusion & Functional Imaging: 7

Probing Cancer with MR II: From Animal Models to Clinical Assessment: 6.5

Current Concepts in Musculoskeletal MRI: 7.5

fMRI Methods: Interpretation & Applications: 3.5

Monday – Friday Programs Scientific Meeting, additional courses and sym-posia, up to 40 credits (not including study group meetings, lunchtime programs, poster sessions, and hands–on workshops).

SMRT Technologist Programs 7.5 Category A CE credits for Saturday, 3 May; 8.5 Category A CE credits for Sunday, 4 May; 16 Total Category A CE credits for SMRT Annual Meeting. Monday SMRT and ISMRM Joint Forum, 2 hours Category A CE.

Category A CE for ISMRM Meeting Additional Continuing Education Credits are available in several other ISMRM Annual Meeting courses. Please refer to the SMRT syllabus for information on which courses and how to get credit for them.

Outstanding Teacher Awards To recognize outstanding educational contribu-tions to the ISMRM meeting, the Annual Meeting Program Committee will acknowl-edge the highest rated speakers in weekend and Monday–Friday educational courses. Recipients of these awards be determined by the evaluation scores which attendees give to speakers. Recipients will be recognized in MR Pulse and on the ISMRM Web site, in addition to receiving certificates of appreciation. We encour-age our attendees to let us know about the outstanding teachers in our educational courses. Please fill out your evaluation forms completely.

Toronto!ISMRM 16th Scientific Meeting & Exhibition • SMRT 17th Scientific Annual Meeting • 3-9 MAY 2008

Declaration of Relevant Financial Relationships

Ackerman, JosephNo Conflict

Adali, Tulay, No Conflict

Adriany, GregorMR Instrument Inc.,Consulting

Aime, SilvioBracco, Consulting

Albert, Mitchell, No Conflict

Alexander, DanielNo Conflict

Alger, JeffryMedQIA (a ClinicalResearch Organization), Consulting

Allen, Peter, No Conflict

Alsop, DavidGeneral Electric, Indepen-dent Contractor (including contracted research)

Altes, Talissa, Merck, Speak-ing, Teaching, Consulting

Anderson, Suzanne ENo Conflict

Arai, Andrew, No Conflict

Ardenkjaer–Larsen, Jan Henrik, General Electric,Employment

Arepally, AravindSurgivision, Intellectual property rights

Artemov, Dmitri, No Conflict

Bali, Maria AntoniettaNo Conflict

Bammer, Roland,No Conflict

Bandettini, Peter, No Conflict

Barker, Gareth, No Conflict

Barkhof, Frederik,No Conflict

Basser, Peter, No Conflict

Beaulieu, ChristianNo Conflict

Beets–Tan, ReginaNo Conflict

Berthezène, YvesNo Conflict

Birn, Rasmus, No Conflict

Bizzi, Alberto, No Conflict

Blaser, Susan, No Conflict

Block, WalterGeneral Electric, Royalty

Bluemke, DavidGeneral Electric,Membership on advisorycommittees or review panels, board membership

Bogdanov, AlexeiNo Conflict

Bolan, Patrick, No Conflict

Bongartz, GeorgBayer, Siemens, Indepen-dent Contractor (including contracted research)Bracco, Speaking, Teaching

Bookheimer, SusanNo Conflict

Bowtell, Richard, No Conflict

Bremerich, Jens, No Conflict

Brindle, KevinGeneral Electric,Research agreement with GE Healthcare

Brown, Robert, No Conflict

Buckley, David, No Conflict

Bulte, Jeff, No Conflict

Buxton, Richard, No Conflict

Bydder, Mark, General Elec-tric,, Research funding

Calamante, FernandoNo Conflict

Caldwell, Curtis, No Conflict

Calhoun, Vince, No Conflict

Carano, RichardGenentech, Employment and stockholdings

Caravan, PeterSiemens, IndependentContractor (includingcontracted research)

Caravan, PeterEpix, Consulting

Carr, James, No Conflict

Catani, Marco, No Conflict

Cercignani, MaraNo Conflict

Chappell, MichaelNo Conflict

Chaumoitre, KathiaNo Conflict

Chen, Qun, No Conflict

Chenevert, ThomasPhilips, Speaking, Teaching

Choyke, PeterPhilips, Researchagreement, on sitescientist provided by Philips

Christensen, GaryMedtronic, Royalty from a licensed patent

Chronik, BlaineGeneral Electric,Research collaborator

Chung, Christine No Conflict

Clare, Stuart, No Conflict

Coakley, Fergus, No Conflict

Cohen, Yoram, No Conflict

Collins, Mark, No Conflict

Comeau, Cindy, No Conflict

Connelly, Alan, No Conflict

Cootes, TimothyGenemation Ltd, Founder share ownership,technical advisor. imorphics ltd, Founding interest, technical advisor.

Corot, ClaireGuerbet, Employment

Cromey, DouglasNo Conflict

Cunningham, CharlesNo Conflict

Cyrus, Tillmann, No Conflict

Dahm, Diane, No Conflict

Damon, Bruce, No Conflict

Dave, Amita, No Conflict

De Vries, Jolanda M.No Conflict

De Zanche, NicolaNo Conflict

Degani, HadassaNo Conflict

Deichmann, RalfNo Conflict

Deichmann, RalfNo Conflict

Desmond, PatriciaNo Conflict

deSouza, NanditaNo Conflict

Dick, AlexanderNo Conflict

Does, Mark, No Conflict

Doria, Andrea, No Conflict

Dousset, VincentNo Conflict

Dow–Mu, Koh, No Conflict

Essig, Marco, No Conflict

Helmberger, ThomasNo Conflict

Driehuys, BastiaanGeneral Electric, Indepen-dent Contractor (including contracted research)

Duensing, RandyPhilips, Employment

Duffau, Hugues, No Conflict

Duyn, Jozef, No Conflict

Dwek, Jerry, No Conflict

Dydak, Ulrike, No Conflict

Dyrby, Tim B., No Conflict

Dzik–Jurasz, AndrzejNo Conflict

Ehman, Richard, No Conflict

Emanuel, Kanal, No conflict

By Invited Speakers in Educational Programs, Organizing Committees, and Other Organizers

The ISMRM is committed to:

1. Insuring balance, independent, objectivity, and scientific rigor in all Continuing Medical Education programs, and2. Presenting CME activities that promote improvements or quality in healthcare and are independent of commercial interests.

To ensure balance, independence, objectivity, and scientific rigor in all CME programs it is the policy of the Society that any person who has influence over the content of a program designated for AMA PRA Category 1 CreditsTM must disclose any real or appar-ent financial interest or other relationship (i.e., grants, research support, consultant, honoraria) that the individual may have with the manufacturers, distributors or providers of any commercial products or services that may be discussed in the presentation.

ISMRM does not imply that such financial interests or relationships are inherently improper or that such interests or relationships would prevent the speaker or organizer from making an objective contribution. However, it is imperative that such financial inter-ests or relationships be identified so that participants at the CME activity may have these facts fully disclosed in advance, and may form their own judgments about the presentations. It remains for the audience to determine whether an individual’s outside interests may reflect a possible bias in either the exposition or the conclusions presented.

Following are the names of all speakers, committee members, and other organizers who had influence over the program content. When individuals have disclosed real or apparent financial interests or relationships with regard to the subject matter of this meet-ing, the interests or relationships are described. If the individual indicated that there were no conflicts, that is shown, as well.

Declaration of Relevant Financial Relationships

Emery, KathleenNo Conflict

Epstein, CharlesNo Conflict

Epstein, FrederickSiemens, Researchsupport

Farahani, KeyvanNo Conflict

Farr, Tracy, No Conflict

Fayad, Zahi, No Conflict

Fennessy, Fiona, No Conflict

Fessler, Jeffrey, No Conflict

Field, Aaron, No Conflict

Filippi, Massimo,BayerTEVA, Biogen–Dompé,Merck–Serono, Genmab,Consulting, Speaking

Fink, Christian, No conflict

Foster, Paula, No Conflict

Friedrich, Matthias G.No Conflict

Fujita, Hiroyuki, No Conflict

Fullerton, GaryPhilips, Independent Con-tractor (including contracted research)

Futterer, Jurgen, No Conflict

Galbraith, SusanBristol–Myers Squibb Co,Employment

Ganter, Carl, No Conflict

Geleijns, Jacob, No Conflict

Gillard, JonathanBayer, Schering,Membership on advisory committees or reviewpanels, board membership,Glaxo–SmithKline,Consulting; Guerbet,Speaking, Teaching

Gillies, Robert, Pfizer,Independent Contractor (in-cluding contracted research)

Girard, Nadine, No Conflict

Glover, Paul, No Conflict

Glunde, Kristine, No Conflict

Golay, Xavier, No Conflict

Gold, Garry, No Conflict

Golman, Klaes, Gen-eral Electric, Imagnia AB, Sweden, Membership on ad-visory committees or review panels, board member-ship, stockholdings in both companies

Goodwin, DouglasNo Conflict

Gowland, PennyNo conflicts

Grant, Patricia EllenNo Conflict

Gribbestad, Ingrid SNo Conflict

Griswold, Mark, Siemens, Independent Contractor (in-cluding contracted research)

Gruell, HolgerPhilips, Employment

Guillerman, RobertNo Conflict

Haacke, Mark, No Conflict

Hardy, ChristopherGeneral Electric,Employment

Hargreaves, BrianNo Conflict

Harisinghani, MukeshNo Conflict

Hatabu, Hiroto, No Conflict

Hawkes, DavidIXICO Ltd, Advisor

Haxby, James, No Conflict

Hecht, ElizabethNo Conflict

Heerschap, Arend, Siemens, Independent Contractor (in-cluding contracted research)

Hendrikse, JeroenNo Conflict

Herskovits, EdwardNo Conflict

Hersman, WilliamXemed LLC, ManagementPosition

Hesley, Gina, Insightec, Primary investigator inindustry–sponsored research

Hill, Richard. No Conflict

Hillenbrand, ClaudiaNo Conflict

Hinks, R. Scott, General Electric, Employment

Hinton–Yates, Denise, Pfizer, Independent Contractor (in-cluding contracted research)

Hodler, Juerg, Bayer, Inde-pendent Contractor (includ-ing contracted research)

Howe, FranklynGuerbet (France), Antisoma (UK), Research support

Hunold, PeterBayer, General Electric, Siemens, Guerbet, Bayer, Speaking, TeachingHutton, Chloe, No Conflict

Ibrahim, Tamer, No Conflict

in ‘t Zandt, Rene, Imagnia AB, Employment, General Electric, Research support

Ito, Katsuyoshi, No Conflict

Jack, Clifford, No Conflict

Jackson, Alan, No Conflict

Jagannathan, N RNo Conflict

Jay, MarkSiemens, Employment

Jenkinson, MarkNo Conflict

Jerosch–Herold, MichaelNo Conflict

Johnson, Glyn, No Conflict

Johnson, Karl, No Conflict

Jones, Derek, No Conflict

Joshi, Sarang, No Conflict

Judd, RobertHeart Imaging Technologies, Management Position

Kaijzel, Eric, No Conflict

Kamel, Ihab, No Conflict

Kanal, EmanuelBracco, Speaking, TeachingBayer, Covidien, GeneralElectric, Membership on ad-visory committees or review panels, board membership, consulting

Kauppinen, RistoMRSTools Inc andCerebricon Ltd, Consulting

Keevil, Stephen, No Conflict

Keith, Brian, No Conflict

Khong, Pek–Lan, No Conflict

Kim, Won Yong, No Conflict

Kim, Won Yong, No Conflict

Kiselev, Valerij, No Conflict

Kobayashi, HisatakaNo Conflict

Korosec, Frank, No Conflict

Kraitchman, DaraSchering, Bayer, BostonScientific Corporation,Research Materials

Kramer, ChristopherNovartis, Membership on advisory committees or review panels, board mem-bership, Siemens, Research equipment support

Kucharczyk, WalterNo Conflict

Kuhl, Christiane, No Conflict

Kurhanewicz, JohnGeneral Electric, Consulting, collaborative research

Kwong, RaymondNo Conflict

Laird, Thaddeus, No Conflict

Lanz, Titus, Rapid Biomedi-cal, Employment

Laub, GerhardSiemens, Employment

Lauenstein, Thomas CNo Conflict

Law, Meng, Siemens,Speaking, TeachingKyron Clinical Imaging,Siemens, Consulting

Leach, MartinSpecialty Scanners, Director

Lee, Vivian, No Conflict

Lee, Seung–KooNo Conflict

Leiner, Tim, No Conflict

Li, Debiao, No Conflict

Lima, Joao, No Conflict

Link, Thomas M., Merck, Speaking, Teaching

Liu, Thomas, No Conflict

Low, Russell, No Conflict

Lu, Hanzhang, No Conflict

Lustig, Michael, No Conflict

Majumdar, SharmilaPfizer, Grantee

Maly Sundgren, PiaNo Conflict

Markl, Michael, No Conflict

Mathews, VincentBayer, Consulting

Maxwell, Ross, No Conflict

Mc Nally, EugeneNo Conflict

McGowan, JosephNo Conflict

McKenzie, CharlesNo Conflict

McKinnon, GraemeGeneral Electric,Employment

Melhem, Elias, No Conflict

Miller, Karla, No Conflict

Mills, GeorgePAREXEL–PerceptiveInformatics, Employment

Mistretta, CharlesNo Conflict

Miyakoshi, Junji, No Conflict

Modo, Mike, No Conflict

Moonen, ChritPhilips, Research support

Moore, Anna, No Conflict

Mori, Susumu, No Conflict

Mosher, TimothyPhilips, Speaker bureau,Speaking, TeachingiGenix Inc, Consulting

Mouridsen, KimNordic Imaging Lab, Poten-tial sub–contractor, software development.

Moy, Linda, No Conflict

Mueggler, ThomasNo Conflict

Mugler, John, Siemens, Research grant, Consulting

Mukherjee, PratikNo Conflict

Murdoch, JamesPhilips, Employment

Neeman, MichalNo Conflict

Nicolay, Klaas, No Conflict

Nishimura, DwightGeneral Electric, Employ-ment, Research support

Norris, David, No Conflict

Nunn, AdrianBracco, Employment

Nyenhuis, John, Medtronic Corporation, ConsultingZimmer Corporation,Research funding

Oakes, TerrenceNo Conflict

Odoj, FlorianRAPID Biomedical GmbH, Membership on advisorycommittees or review pan-els, board membership

Ohno, YoshiharuNo Conflict

Omary, Reed, No Conflict

Oshinski, John, Philips, Inde-pendent Contractor (includ-ing contracted research)

Overweg, JohanPhilips, Employment

Padhani, AnwarSynarc Inc. SF, Siemens,Consulting

Parizel, Paul M.Siemens, Consulting

Park, Hae–JeongNo Conflict

Patay, Zoltan, No Conflict

Paulmurugan, RamasamyNo Conflict

Payne, Geoffrey, No Conflict

Peter, Hunold, General Electric, Guerbet, Speaking, Teaching

Pfirrmann, Christian W. A.No Conflict

Pierpaoli, Carlo, No Conflict

Pipe, James, No Conflict

Plewes, Donald, No Conflict

Port, John, No Conflict

Potter, Hollis, No Conflict

Prince, Martin, GE, Philips, Hitachi, Bayer, Berlex,Schering, Epix, Bracco, Nemoto, Topspin, Medrad,patent agreement, royalty

Prince, JerryDiagnosoft, Inc., Founder

Schoenberg, StefanNo Conflict

Pruessmann, KlaasNo Conflict

Quick, Harald H.No Conflict

Raman, SubhaSiemens, research agreement

Ramasamy, PaulmuruganNo Conflict

Ratib, Osman, No Conflict

Reddy, Ravinder, No Conflict

Reddy, GauthamNo Conflict

Regatte, RavinderNo Conflict

Reykowski, ArneInvivo Corporation,Management Position

Roberts, Timothy, Siemens, Speaking, Teaching, General Electric, Membership on advisory committees orreview panels, boardmembership, Genentech Inc., Bracco, Consulting

Robinson, SimonNo Conflict

Ronen, Sabrina, No Conflict

Rosen, Mark, No Conflict

Rossi, Andrea, No Conflict

Rowley, HowardGeneral Electric,Research supportNuvelo, Consulting

Rudin, Markus, No Conflict

Ruehm, Stefan, No Conflict

Runge, Val, No Conflict

Russell, Alan, No Conflict

Rutt, Brian, General Electric,Membership on advisory committees or review panels, board membership

Sack, Ingolf, No Conflict

Sakuma, HajimeNo Conflict

Salonen, David, No Conflict

Saltz, Joel, No Conflict

Santyr, Giles, No Conflict

Scheffler, Klaus, No Conflict

Schick, Fritz, No Conflict

Schmitt, FranzSiemens, Employment

Schröder, Leif, No Conflict

Schwitter, JuergGeneral Electric, Consulting

Seethamraju, Ravi TejaSiemens, Employment

Seifert, Frank, No Conflict

Selvanayagam, JosephNo Conflict

Seto, Belinda, No Conflict

Sherry, Dean, Macrocyclics, Inc., Scientific founder

Simonetti, OrlandoSiemens, Consulting

Sinkus, Ralph, No Conflict

Sirlin, Claude, General Elec-tric, Berlex, Baer, Investiga-tive researcher

Skare, Stefan, No Conflict

Sloane, Bonnie, No Conflict

Smith, J Keith, No Conflict

Sosnovik, David, No Conflict

Speck, Oliver, Siemens, Inde-pendent Contractor (includ-ing contracted research)

Spuentrup, ElmarNo Conflict

Stanisz, Greg, No Conflict

Steinbach, LynneNo Conflict

Strijkers, GustavNo Conflict

Sunaert, Stefan, No Conflict

Takahara, Taro, No Conflict

Taouli, Bachir, No Conflict

Tempany, Clare, Insightec Inc., Research support and consulting agreement

Thoeny, Harriet, No Conflict

Thomas, AdrianSiemens, Consulting

Thulborn, Keith, Thulborn Associates, Inc., OwnerGeneral Electric, Speaking, teaching, research contract

Tkac, Ivan, No Conflict

Togashi, Kaori, No Conflict

Trattnig, SiegfriedNo Conflict

Tropp, James, General Elec-tric, Employment

Tsao, JeffreyNovartis, Employment

Turner, Robert, No Conflict

Ullmann, Peter, Bruker Bio-spin, Employment

van Beek, EdwinGeneral Electric, Siemens Medical Systems, Research support, equipment loan

Van Beers, BernardNo Conflict

van Buchem, MarkNo Conflict

Van der linden, Anne–MarieNo Conflict

Van Hecke, WimNo Conflict

van Osch, MatthiasNo Conflict

Vanhoutte, GreetjeNo Conflict

Vaughan, JohnMR Instruments

Vecchia, Paolo, No Conflict

Venkatesh, SudhakarNo Conflict

Vigneron, DanielGeneral Electric, Research Grant Investigator, Indepen-dent Contractor (including contracted research)

Vilgrain, Valerie, No Conflict

Walczak, Piotr, No Conflict

Wald, LawrenceGlaxo–SmithKline, Siemens Consulting

Wang, Shih–chang, General Electric, Siemens, Partnershiparrangement, Schering,Membership on advisory committees or review panels, board membership

Wang, JiongjiongNo Conflict

Wang, Yi, No Conflict

Warfield, Simon, No Conflict

Warner, RoryVarian, Employment

Webb, Andrew, No Conflict

Wegener, SusanneNo Conflict

Weisser, AlexanderRapid Biomedical GmbH, Employment

Weitekamp, Daniel P.No Conflict

Wells, William, No Conflict

Wen, Han, No Conflict

Wenger, DorisNo Conflict

West, CatharineNo Conflict

Wheeler–Kingshott, ClaudiaNo Conflict

White, LawrenceNo Conflict

Wieben, Oliver, No Conflict

Wild, Jim, No Conflict

Williamson, Eric, General Electric, Consulting, Bayer, Consulting, grant/researchsupport; Siemens, Member-ship on advisory committeesor review panels, board membership

Willinek, Winfried, Philips, Bracco, General Electric, Speaking, Teaching; Toshiba,Schering, Speaking, Teach-ing Consultant, Advisory Board

Winter, PatrickTyco–Mallinckrodt,EmploymentKereos, Inc., Novartis,Consulting

Wintersperger, BerndBayer, Siemens,Speaking, Teaching

Wolf, Ronald, No Conflict

Wong, Eric, No Conflict

Wood, John, Novartis Pharma, Consultant, Indepen-dent Research; Contractor, Speaking; Apotex,Speaking, Teaching

Woolrich, MarkNo Conflict

Wright, GrahamGeneral Electric,Membership on advisory committees or review panels, board membership

Yablonskiy, DmitriyNo Conflict

Yacoub, Essa, No Conflict

Yamada, Kei, No Conflict

Yankeelov, ThomasNo Conflict

Zakian, Kristen, No Conflict

Zhong, Jianhui, No Conflict

Zoga, Adam, No Conflict

Zur, YuvalHitachi, General Electric, TopSpin Medical,Employment

Declaration of Relevant Financial Relationships

Declaration of Relevant Financial Relationships

By Authors of Proffered papersThe ISMRM is committed to:

1. Insuring balance, independent, objectivity, and scientific rigor in all Continuing Medical Education programs, and2. Presenting CME activities that promote improvements or quality in healthcare and are independent of commercial interests.

To ensure balance, independence, objectivity, and scientific rigor in all CME programs it is the policy of the Society that any person who has influence over the content of a program designated for AMA PRA Category 1 CreditsTM must disclose any real or appar-ent financial interest or other relationship (i.e., grants, research support, consultant, honoraria) that the individual may have with the manufacturers, distributors or providers of any commercial products or services that may be discussed in the presentation.

ISMRM does not imply that such financial interests or relationships are inherently improper or that such interests or relationships would prevent the speaker or organizer from making an objective contribution. However, it is imperative that such financial inter-ests or relationships be identified so that participants at the CME activity may have these facts fully disclosed in advance, and may form their own judgments about the presentations. It remains for the audience to determine whether an individual’s outside interests may reflect a possible bias in either the exposition or the conclusions presented.

Following are the program numbers, names of all authors of proffered papers, and whether or not there are conflicts. If individuals have disclosed real or apparent financial interests or relationships with regard to the subject matter of this meeting, the interests or relationships are described. If the individual indicated that there were no conflicts, that is shown as well.

4 Holdsworth, SamanthaNo conflicts

5 Liu, Chunlei, No conflicts

6 Boubertakh, RedhaNo conflicts

7 Seiberlich, NicoleNo conflicts

8 Beatty, PhilipGeneral Electric, Ownership interest, Employment

9 Zhang, Jian, No conflicts

10 Breuer, FelixNo conflicts

11 Malik, ShaihanNo conflicts

12 Eggers, HolgerPhilips, Employment

13 Liu, Bo, No conflicts

14 Schmieder, AnneKereos, Ownership interest Philips, Employment

15 van Tilborg, GeraldaNo conflicts

16 Blé, François–XavierNo conflicts

17 Keupp, JochenPhilips, Employment

18 Strijkers, GustavNo conflicts

19 Li, Alex, No conflicts

20 Zabow, GaryNo conflicts

21 Cormode, DavidNo conflicts

22 Miserus, Robbert–JanNo conflicts

23 Bartelle, BenjaminNo conflicts

24 Lui, Su, No conflicts

25 Jansen, JacobusNo conflicts

26 Zhu, Quan, No conflicts

27 Karunanayaka,Prasanna, No conflicts

28 Qiu, DeqiangNo conflicts

29 Tomasi, DardoNo conflicts

30 Fonteijn, HubertNo conflicts

31 Schmithorst, VincentNo conflicts

32 Schwarz, AdamNo conflicts

33 Landman, BennettNo conflicts

34 Wu, Yu–ChienNo conflicts

35 Ozarslan, EvrenNo conflicts

36 Zhou, XiaohongNo conflicts

37 Hui, EdwardNo conflicts

38 Liu, Chunlei, No conflicts

39 Yeh, Chun–HungNo conflicts

40 Yeh, Fang–ChengNo conflicts

41 Nedjati–Gilani, ShahrumNo conflicts

42 Hong, Xin, No conflicts

43 Ge, Lan, No conflicts

44 Jung, Bernd, No conflicts

45 Xue, HuiSiemens, Employment

46 Ferreira, PedroNo conflicts

47 Su, Mao–Yuan No conflicts

48 Dharmakumar, RohanNo conflicts

49 Knowles, BenjaminNo conflicts

50 McCommis, KyleNo conflicts

51 Stehning, ChristianPhilips, Employment

52 Maintz, DavidNo conflicts

53 Wang, PengNo conflicts

54 Anderson, AdamNo conflicts

55 Carpenter, DavidNo conflicts

56 Ardekani, BabakNo conflicts

57 Lui, Su, No conflicts

58 Diwadkar, VaibhavNo conflicts

59 Greenwald, MarkNo conflicts

60 Lin, Ai–LingNo conflicts

61 Orlichenko, AntonNo conflicts

62 Gagnon, YannNo conflicts

63 Nour, SherifNo conflicts

64 Cernicanu, AlexandruNo conflicts

65 Krafft, Axel, No conflicts

66 Köhler, MaxPhilips, Employment

67 Schmitz, AnnemarieNo conflicts

68 Rata, MihaelaNo conflicts

69 Peller, MichaelNo conflicts

70 Eker, Omer, No conflicts

71 Treat, LisaNo conflicts

72 Chow, AprilNo conflicts

73 van den Bergen, BobNo conflicts

74 Graesslin, IngmarPhilips, Employment

75 Wang, ZhangweiNo conflicts

76 Wang, Hua, No conflicts

77 Hue, YiK–KiongNo conflicts

78 Lattanzi, RiccardoNo conflicts

79 Oh, SukhoonNo conflicts

80 Webb, AndrewNo conflicts

81 Glover, PaulNo conflicts

82 Feldman, RebeccaNo conflicts

83 Klatt, Dieter, No conflicts

84 Yin, Meng, No conflicts

85 Salameh, NajatNo conflicts

86 Wang, YuenanNo conflicts

87 Tsuda, NatsukoBayer Healthcare/Bayer Schering, Employment

88 Leinhard, OlofNo conflicts

89 Brauer, ManfredNo conflicts

90 Hillenbrand, ClaudiaNo conflicts

91 Chandarana, HershNo conflicts

92 Wylezinska, MarzenaNo conflicts

93 Dashdorj, NaranjargalNo conflicts

94 Zhu, David, No conflicts

95 James, GeorgeNo conflicts

96 Golestani, Ali–Mohammad, No conflicts

97 Valsasina, PaolaNo conflicts

98 Voets, NatalieNo conflicts

Declaration of Relevant Financial Relationships

99 Wang, JianliNo conflicts

100 Goldstone, AnthonyNo conflicts

101 Murphy, EricNo conflicts

102 Venkatraman, Vijay KNo conflicts

103 Bock, JelenaNo conflicts

104 Fung, MaggieGeneral Electric,Employment

105 Haider, CliftonNo conflicts

106 Choi, GilwooNo conflicts

107 Zhang, XiaomingNo conflicts

108 Wu, Yan, No conflicts

109 Maki, JeffreyNo conflicts

110 Wu, YiJingNo conflicts

111 Maderwald, StefanNo conflicts

112 Michaely, HenrikBayer Healthcare/Bayer Schering, Research Grant

113 Kabli, SamiraNo conflicts

114 Tkac, IvanNo conflicts

115 Yang, ShaolinNo conflicts

116 Violante, InesNo conflicts

117 Jiang, LihongNo conflicts

118 Nabuurs, ChristineNo conflicts

119 Patel, AnantNo conflicts

120 Zhu, Xiao–HongNo conflicts

121 Braakman, NielsNo conflicts

122 Du, Fei, No conflicts

123 Li, XiaojuanNo conflicts

124 Li, Wei, No conflicts

125 Multanen, JuhaniNo conflicts

126 Krishnan, NityaPfizer, Grant support

127 Taylor, CarmenNo conflicts

128 Mattila, LauriNo conflicts

129 Welsch, GoetzNo conflicts

130 Nieminen, MiikaNo conflicts

131 Mamisch, TallalSiemens, Consulting fee,

132 Greaves, LauraNo conflicts

133 Finsterbusch, JürgenNo conflicts

134 Aksoy, MuratNo conflicts

135 Gallichan, DanielNo conflicts

136 Bar–Shir, AmnonNo conflicts

137 Smith, StephenNo conflicts

138 Pasternak, OferNo conflicts

139 Walker, LindsayNo conflicts

140 Leemans, AlexanderNo conflicts

141 Haldar, JustinNo conflicts

142 Heemskerk, AnnerietNo conflicts

143 Brunner, DavidNo conflicts

144 Alagappan, Vijay-anand, No conflicts

145 Stang, PascalNo conflicts

146 Scott, GreigNo conflicts

147 Kirilina, EvgeniaNo conflicts

148 Wiggins, GrahamNo conflicts

149 Paska, JanNo conflicts

150 Zhai, ZhiyongNo conflicts

151 Weber, EwaldNo conflicts

152 Vaughan, ThomasBruker Biospin, Business – product developmentMR Instruments, Inc., Ownership interest, Board Membership

153 Goense, JozienNo conflicts

154 Kim, Seong–GiNo conflicts

155 Liu, Junjie, No conflicts

156 Chen, Xu, No conflicts

157, Shmuel, AmirNo conflicts

158 Nair, GovindNo conflicts

159 Ringe, WendyNo conflicts

160 Zhang, NanyinNo conflicts

161 Song, XiaomuNo conflicts

162 Pawela, ChristopherNo conflicts

163 Xu, JunqianNo conflicts

164 Alonzi, RobertoNo conflicts

165 Gibbs, PeterNo conflicts

166 Langer, DeannaNo conflicts

167 Alonzi, RobertoNo conflicts

168 Jia, GuangNo conflicts

169 Riches, SophieNo conflicts

170 Zhang, BaoNo conflicts

171 Metzger, GregoryPhilips, Consulting fee,

172 Liu, Min, No conflicts

173 Serai, SurajNo conflicts

174 Hsu, Yi–HuaNo conflicts

175 Evgenov, NataliaNo conflicts

176 Jirak, DanielNo conflicts

177 Balchandani, PritiNo conflicts

178 Liu, WeiPhilips, Employment

179 Shemesh, NoamNo conflicts

180 Kyrtatos, PanagiotisNo conflicts

181Lordanova, BistraNo conflicts

182 Wong, EricNo conflicts

183 Helle, MichaelNo conflicts

184 Dai, WeiyingNo conflicts

185 Hendrikse, JeroenNo conflicts

186 Luh, Wen–MingNo conflicts

187 Teeuwisse, WouterNo conflicts

188 St. Lawrence, KeithNo conflicts

189 Varela, MartaNo conflicts

190 Qiu, MaolinNo conflicts

191 Petersen, EsbenNo conflicts

192 El–Sharkawy, AbdEl-Monem, No conflicts

193 Schweizer, SusanneNo conflicts

194 Lupo, JanineNo conflicts

195 Hu, SimonNo conflicts

196 Boumezbeur, FNo conflicts

197 Liu, SiyuanNo conflicts

198 Romanzetti, SandroNo conflicts

199 Stobbe, RobertNo conflicts

200 Fenty, MatthewNo conflicts

201 Chang, YulinNo conflicts

202 Graesslin, IngmarPhilips, Employment

203 Curcic, JelenaNo conflicts

204 Uribe, SergioNo conflicts

205 Liu, JunminNo conflicts

206 Spincemaille, PascalNo conflicts

207 Frauenrath, TobiasNo conflicts

208 Chan, CheukNo conflicts

209 Ooi, MelvynNo conflicts

210 Zhong, XiaodongNo conflicts

211 Derbyshire, J.No conflicts

215 Donahue, ManusPhilips, Honoraria,

216 Chen, J.No conflicts

217 Frahm, JensNo conflicts

218 Harshbarger, ToddNo conflicts

219 Devlin, HannahNo conflicts

220 Ho, Yi–ChingNo conflicts

221 Wade, AlexNo conflicts

222 Kennerley, AneurinNo conflicts

223 Kohno, SatoruNo conflicts

224 Chen, YufenNo conflicts

225 Balchandani, PritiNo conflicts

226 Kerr, AdamNo conflicts

227 Deng, WeiranNo conflicts

228 Sung, KyunghyunNo conflicts

229 Moeller, SteenNo conflicts

230 Lebel, RobertNo conflicts

231 Preibisch, ChristineNo conflicts

232 Boulant, NicolasNo conflicts

233 Huang, SusieNo conflicts

234 Yarnykh, VasilyNo conflicts

235 Ragan, DustinNo conflicts

236 Winkelmann, StefaniePhilips, Employment

237 Wiggins, ChristopherNo conflicts

238 Deng, JieNo conflicts

239 Blume, UlrikeNo conflicts

240 Deoni, SeanNo conflicts

241 Stehning, ChristianPhilips, Employment

242 Brekken, ChristianNo conflicts

243 Kozlowski, PiotrNo conflicts

244 Glunde, KristineNo conflicts

245 Iorio, EgidioNo conflicts

Declaration of Relevant Financial Relationships

246 Eliyahu, GalitNo conflicts

247 Iorio, EgidioNo conflicts

248 Al–Saffar, NadaNo conflicts

249 Ijare, OmkarNo conflicts

250 Keshari, KayvanNo conflicts

251 Gisselsson, AnnaGeneral Electric, financial port, Imagnia AB, Owner-ship interest, Employment

252 Mancuso, AnthonyNo conflicts

253 Stoyanova, RadkaNo conflicts

254 Marjanska, Malgorza-ta, No conflicts

255 Wadghiri, YoussefNo conflicts

256 Meadowcroft, MarkNo conflicts

257 Braakman, NielsNo conflicts

258 Kranz, FelicitasNo conflicts

259 Weidensteiner, Clau-dia, Hoffman–LaRoche,Employment

260 Zhang, JiangyangPhilips, Research port,Honoraria,

261 Wu, ZhilinNo conflicts

262 Mueller, SusanneNo conflicts

263 DeArment, LindsiNo conflicts

264 Singleton, KyleNo conflicts

265 Wu, OnaNo conflicts

266 Gupta, RakeshNo conflicts

267 Zhan, WangNo conflicts

268 Gupta, RakeshNo conflicts

270 van der Palen, RoelNo conflicts

271 Tonon, CaterinaNo conflicts

272 Zhuo, JiachenNo conflicts

273 Newcombe, VirginiaNo conflicts

274 Seevinck, PeterNo conflicts

275 Woodrum, DavidSiemens, Consulting fee,

276 Gilson, WesleySiemens, Employment

277 Wang, DingxinNo conflicts

278 Matsuoka, YuichiroNo conflicts

279 Sathyanarayana, Shashank, No conflicts

280 Tse, Zion Tsz HoNo conflicts

281 Lister, KevinNo conflicts

282 Park, Yong–LaeNo conflicts

283 Weiss, SteffenPhilips, Employment

284 Pathak, ArvindNo conflicts

285 Ong, HenryNo conflicts

286 Nieman, BrianNo conflicts

287 Pavlin, TinaNo conflicts

288 Spehl, TimoNo conflicts

289 Bock, MichaelNo conflicts

290 Li, CharlesNo conflicts

291 Weiger, MarkusBruker Biospin, Employment

292 Sinha, TuhinNo conflicts

293 Peter, JoergNo conflicts

294 Prince, MartinNo conflicts

295 Hope, ThomasNo conflicts

296 Sieber, MartinBayer Healthcare/Bayer Schering, Employment

297 Mazhar, SameerNo conflicts

298 Foster, ZekeNo conflicts

299 Hornak, JosephNo conflicts

300 Caravan, PeterSiemens, Research grantEpix, Consulting fee

301 Sieber, MartinBayer Healthcare/Bayer Schering, Employment

302 Pedrosa, IvanNo conflicts

303 Recker, RebeccaNo conflicts

304 Jiang, QuanNo conflicts

305 Yushmanov, VictorNo conflicts

306 Farr, TracyNo conflicts

307 Wu, Sheng–PingNo conflicts

308 Harloff, AndreasNo conflicts

309 Christensen, SorenNo conflicts

310 Liu, Fang, No conflicts

311 Mandell, Daniel

312 Kansagra, AkashNo conflicts

313 Fung, MaggieGeneral Electric,Employment

314 Shankaranarayanan, Ajit, General ElectricEmployment

315 Yang, Qi, No conflicts

316 Lee, Hsu–LeiNo conflicts

317 Lai, Peng, No conflicts

318 Macedo, RobsonNo conflicts

319 Gerretsen, SuzanneNo conflicts

320 Li, Tao, No conflicts

321 von Bary, ChristianNo conflicts

322 Stehning, ChristianPhilips, Employment

323 Ling, WenNo conflicts

324 Staroswiecki, ErnestoNo conflicts

325 Bolbos, RaduNo conflicts

326 Cheng, JonathanNo conflicts

327 Siversson, CarlNo conflicts

328 Li, WeiNo conflicts

329 Lin, Ping–ChangNo conflicts

330 Raya, JoseNo conflicts

331 Jacobson, JoshuaNo conflicts

332 Du, JiangNo conflicts

333 Lin, Fa–HsuanNo conflicts

334 Grotz, ThimoNo conflicts

335 Atkinson, IanNo conflicts

336 Doneva, MariyaNo conflicts

337 Bilgin, Ali, No conflicts

338 Schirra, CarstenNo conflicts

339 Wu, HuiminNo conflicts

340 Adluru, GaneshSiemens, Employment

341 Fischer, AndréNo conflicts

342 Samsonov, AlexeyNo conflicts

343 Sanchez Lopez,Hector, No conflicts

344 de Bever, JoshuaNo conflicts

345 Poole, MichaelNo conflicts

346 Green, DanVarian, Employment

347 Seeber, DerekGeneral Electric,Employment

348 Stang, PascalNo conflicts

349 Thiel, FlorianNo conflicts

350 Wehrl, HansNo conflicts

351 Bindseil, GeronNo conflicts

352 Green, DanVarian, Employment

353 Nehrke, KayPhilips, Employment

354 Brunner, DavidNo conflicts

355 Kerr, AdamNo conflicts

356 Zhao, ShaNo conflicts

357 Leinhard, OlofNo conflicts

358 Schär, MichaelPhilips, Employment

359 Zhong, KaiNo conflicts

360 Hsu, Jung–JiinNo conflicts

361 Park, Jang–YeonNo conflicts

362 Wang, DingxinNo conflicts

363 Hamans, BobNo conflicts

364 Procissi, DanielNo conflicts

365 Jansen, SanazNo conflicts

366 Krishnamachary, Balaji, No conflicts

367 Rommel, DenisNo conflicts

368 Garbow, JoelNo conflicts

369 Yaligar, JadegoudNo conflicts

370 Zhang, XiaomengNo conflicts

371 Simões, RuiNo conflicts

372 Lui, TraceyNo conflicts

373 Asllani, IrisNo conflicts

374 Boumezbeur, FawziNo conflicts

375 Boumezbeur, FawziNo conflicts

376 Pagani, ElisabettaNo conflicts

377 Li, ZhihaoNo conflicts

378 Hardy, PeterNo conflicts

379 Gattu, RamtilakNo conflicts

380 Saito, NaokoNo conflicts

381 Hollingsworth, KierenNo conflicts

382 Ropele, StefanNo conflicts

383 Carvalho, JoaoNo conflicts

384 Santos, JuanNo conflicts

385 Nielsen, Jon–FredrikNo conflicts

386 Stadlbauer, AndreasNo conflicts

387 von Spiczak, JochenNo conflicts

388 Hardy, ChristopherGeneral Electric,Employment

Declaration of Relevant Financial Relationships

389 Westenberg, JosNo conflicts

390 Barker, AlexNo conflicts

391 Gatehouse, PeterNo conflicts

392 Wiesinger, FlorianGeneral Electric,Employment

393 Wang, ChengboSiemens

394 Yablonskiy, DmitriyNo conflicts

395 Santoro, DavideNo conflicts

396 Kraayvanger, RyanNo conflicts

397 Yu, JiangshengNo conflicts

398 Mistry, NileshNo conflicts

399 Blé, François–XavierNo conflicts

400 Ohno, YoshiharuNo conflicts

401 Naish, JosephineNo conflicts

402 Donahue, ManusPhilips, Honoraria

403 Urayama, Shin–ichiNo conflicts

404 Mazerolle, ErinNo conflicts

405 Drobnjak, IvanaNo conflicts

406 Lu, HanzhangNo conflicts

407 Tang, LinNo conflicts

408 Zhu, Xiao–HongNo conflicts

409 Horovitz, SilvinaNo conflicts

410 Stevenson, ClaireNo conflicts

411 Vidyasagar, RishmaNo conflicts

415 Engström, MathiasNo conflicts

416 Nielsen, Jon–FredrikNo conflicts

417 Skare, StefanNo conflicts

418 Pipe, JamesNo conflicts

419 Deng, JieNo conflicts

420 Pandit, PrachiNo conflicts

421 Sica, ChristopherNo conflicts

422 Kim, Yoon–ChulNo conflicts

423 Lustig, MichaelNo conflicts

424 Moriguchi, HisamotoNo conflicts

425 Kreher, BjörnNo conflicts

426 Cook, PhilipNo conflicts

427 Hagmann, PatricNo conflicts

428 Welbourne, StephenNo conflicts

429 Kindlmann, GordonNo conflicts

430 Kezele, IrinaNo conflicts

431 Close, TomNo conflicts

432 Coward, HannahNo conflicts

433 Demiralp, CagatayNo conflicts

434 Brunner, DavidNo conflicts

435 Zhang, XiaoliangNo conflicts

436 Korn, MatthiasNo conflicts

437 Wu, Bing, No conflicts

438 Ibrahim, TamerNo conflicts

439 Grafendorfer, ThomasNo conflicts

440 Lee, Ray, No conflicts

441 Ahmad, MunirNo conflicts

442 Nascimento, GeorgeNo conflicts

443 Wosik, JarekNo conflicts

444 Hassid, YaronNo conflicts

445 Woenne, EvaNo conflicts

446 Heilmann, MelanieNo conflicts

447 Kraft, SusanNo conflicts

448 Sarin, HemantNo conflicts

449 Ungersma, SharonGenentech, Inc., Employ-ment

450 Pacheco–Torres, JesusNo conflicts

451 Little, Ross, No conflicts

452 Kim, SungheonNo conflicts

453 Njus, JeffreyNo conflicts

454 Tofts, Paul, No conflicts

455 Dujardin, MartineNo conflicts

456 Zhang, JeffNo conflicts

457 Atthe, BharathNo conflicts

458 Salman, KhalilNo conflicts

459 Knowles, NegarNo conflicts

460 Sourbron, StevenNo conflicts

461 Venkatesh, SudhakarNo conflicts

462 Attenberger, UlrikeNo conflicts

463 Bayram, ErsinGeneral Electric,Employment

464 Du, YipingNo conflicts

465 Velikina, JuliaNo conflicts

466 Jeong, HyunNo conflicts

467 Kimura, TokunoriNo conflicts

468 Saloner, DavidNo conflicts

469 Hadizadeh, DariuschNo conflicts

470 Meckel, StephanNo conflicts

471 Moenninghoff,Christoph, No conflicts

472 Zwanenburg, JacoNo conflicts

473 von Morze, CorneliusNo conflicts

474 Qiu, BenshengNo conflicts

475 Branca, TamaraNo conflicts

476 Bennett, KevinNo conflicts

477 von Elverfeldt, DominikNo conflicts

478 Sibson, NicolaNo conflicts

479 Link, ThomasNo conflicts

480 Koole, RolfNo conflicts

481 Kluza, EwelinaNo conflicts

482 Mao, Hui, No conflicts

483 Ciocan, RazvanNo conflicts

484 Tao, GuozhiNo conflicts

485 Archip, NeculaiNo conflicts

486 Lordanescu, GeorgeNo conflicts

487 Wong, WilburNo conflicts

488 Balu, NiranjanNo conflicts

489 Antiga, LucaNo conflicts

490 Gloor, MonikaNo conflicts

491 Quirk, JamesNo conflicts

492 Graff, ChristianNo conflicts

493 Banerji, AnitaNo conflicts

494 Chandarana, HershNo conflicts

495 Robson, PhilipNo conflicts

496 Hajnal, JoPhilips, Grant port

497 Punwani, ShonitNo conflicts

498 Binser, TobiasNo conflicts

499 Hopewell, PaigeNo conflicts

500 Berggruen, sentaNo conflicts

501 Braithwaite, AdamNo conflicts

502 Brau, AnjaGeneral Electric,Employment

503 Frulio, NoraNo conflicts

504 Laule, CorneliaNo conflicts

505 Seewann, AlexandraNo conflicts

506 Eissa, AmirNo conflicts

507 Hammond, KathrynNo conflicts

508 Mainero, CaterinaNo conflicts

509 Srinivasan, RadhikaNo conflicts

510 Schmierer, KlausNo conflicts

511 Madelin, Guillaume No conflicts

512 Hirsch, JochenNo conflicts

513 Roosendaal, StefanNo conflicts

514 Paulis, LeonieNo conflicts

515 de Smet, MariskaNo conflicts

516 Makowski, MarcusNo conflicts

517 von Bary, ChristianNo conflicts

518 Lobatto, MarkNo conflicts

519 McCommis, KyleNo conflicts

520 Zhang, ZhuoliNo conflicts

521 Duivenvoorden,Raphael, No conflicts

522 Lin, AlexanderNo conflicts

523 Frydrychowicz, AlexNo conflicts

524 De Groof, GeertNo conflicts

525 Watanabe, TakashiNo conflicts

526 Wu, CarolynNo conflicts

527 Gozzi, AlessandroNo conflicts

528 Massaad, CynthiaNo conflicts

529 Szulc, KamilaNo conflicts

530 Gobbo, OlivieroNo conflicts

531 Chuang, Kai–HsiangNo conflicts

532 Chan, KevinNo conflicts

533 Serrano, FaridisNo conflicts

534 Gomberg, BryonMicroMRI Inc., Ownershipinterest, Employment

Declaration of Relevant Financial Relationships

535 Carballido–Gamio, Julio, No conflicts

536 Techawiboonwong, Aranee, No conflicts

537 Wang, Yi, No conflicts

538 Cao, HaihuiNo conflicts

539 Chesnick, IngridNo conflicts

540 de Rochefort, LudovicNo conflicts

541 Alkalay, RonNo conflicts

542 Saar, GalitNo conflicts

543 Zuo, Jin, No conflicts

544 Lee, Jong–HwanNo conflicts

545 Moench, TobiasNo conflicts

546 Robertson, JohnFralex Therapeutics, Owner-ship interest; Dr. Thomas and Dr. Prato are the found-ers of Fralex Therapeutics and hold stock in the company.

547 Aznárez–Sanado, Maite, No conflicts

548 Qiu, MaolinNo conflicts

549 Ringe, WendyNo conflicts

550 Rao, HengyiNo conflicts

551 Zhang, NaNo conflicts

552 Gozzi, AlessandroNo conflicts

553 No conflicts

554 Awate, SuyashNo conflicts

555 Song, TingNo conflicts

556 Li, ChunmingNo conflicts

557 Bagher–Ebadian,Hassan, No conflicts

558 Joshi, NiranjanNo conflicts

559 Belaroussi, BoubakeurNo conflicts

560 Wardlaw, GraemeNo conflicts

561 Yang, ZhengyiNo conflicts

562 Buelow, ThomasPhilips, Employment

563 Jansen, JacobusNo conflicts

564 Laitinen, TeemuNo conflicts

565 Choe, AnnNo conflicts

566 Concha, LuisNo conflicts

567 Barazany, DanielNo conflicts

568 Schnell, SusanneNo conflicts

569 Cohen–Adad, JulienNo conflicts

570 Colvin, DanielNo conflicts

571 Sinha, ShantanuNo conflicts

572 McNab, JenniferNo conflicts

573 Ellegood, JacobNo conflicts

574 Bucholz, ElizabethNo conflicts

575 Berry, ChristopherNo conflicts

576 Seland, JohnNo conflicts

577 Heijman, EdwinNo conflicts

578 Wu, Yin, No conflicts

579 Thattaliyath, BijoyNo conflicts

580 Zhong, XiaodongNo conflicts

581 Wu, Yin, No conflicts

582 Hamilton, AmandaNo conflicts

583 McCommis, KyleNo conflicts

584 Li, Xin, No conflicts

585 Ramsay, ElizabethNo conflicts

586 Rakow–Penner,Rebecca, No conflicts

587 Granlund, KristinNo conflicts

588 Eyal, ErezNo conflicts

589 Li, Ka–LohNo conflicts

590 Bathen, ToneNo conflicts

591 Yankeelov, ThomasNo conflicts

592 Lipnick, ScottNo conflicts

593 Lenkinski, RobertNo conflicts

594 Henning, AnkeNo conflicts

595 Lin, Fa–HsuanNo conflicts

596 Bito, YoshitakaHitachi, Employment

597 Kunz, NicolasNo conflicts

598 Otazo, RicardoNo conflicts

599 Gagoski, BorjanNo conflicts

600 Gu, MengNo conflicts

601 Young, RichardNo conflicts

602 Fleysher, LazarNo conflicts

603 Valette, JulienNo conflicts

604 Klarhöfer, MarkusNo conflicts

605 Wu, Wen–ChauNo conflicts

606 Lu, Kun, No conflicts

607 Meyerspeer, MartinNo conflicts

608 Befroy, DouglasNo conflicts

609 Velan, S. SendhilNo conflicts

610 van den Broek, NicoleNo conflicts

611 Prompers, JeanineNo conflicts

612 Hollingsworth, KierenNo conflicts

613 Kan, HermienNo conflicts

614 Lattanzi, RiccardoNo conflicts

615 Brunner, DavidNo conflicts

616 Setsompop, KawinNo conflicts

617 Kerr, AdamNo conflicts

618 Xu, Dan, General Electric, Employment

619 Alagappan, Vijay-anand, No conflicts

620 Zelinski, AdamNo conflicts

621 Graesslin, IngmarPhilips, Employment

622 Deng, WeiranNo conflicts

626 Bleeker, EgbertNo conflicts

627 Gall, PeterNo conflicts

628 Zaharchuk, GregNo conflicts

629 Ziegelitz, DoertheNo conflicts

630 Emblem, KyrreNo conflicts

631 Liao, Yeng–PengNo conflicts

632 Cheng, Hai–LingNo conflicts

633 Kaul, MichaelNo conflicts

634 Ashton, EdwardNo conflicts

635 Quarles, C.No conflicts

636 SUN, PhillipNo conflicts

637 Keupp, JochenPhilips, Employment

638 SUN, PhillipNo conflicts

639 Liimatainen, TimoNo conflicts

640 Kato, YoshinoriNo conflicts

641 Schäfer, AndreasNo conflicts

642 Shmueli, KarinNo conflicts

643 Liu, TianNo conflicts

644 Ghugre, NileshNo conflicts

645 Ghugre, NileshNo conflicts

646 Johnson, KevinNo conflicts

647 Brodsky, EthanNo conflicts

648 Yu, HuanzhouGeneral Electric, Employ-ment

649 Wu, HochongNo conflicts

650 Huo, DonglaiNo conflicts

651 Saranathan, Manojku-mar, General Electric,Employment

652 Yu, HuanzhouGeneral Electric,Employment

653 Tsao, JeffreyNovartis, Ownershipinterest, Employment

654 Lu, WenmiaoNo conflicts

655 Ma, JingfeiGeneral Electric, Royalty

656 Haney, ChadNo conflicts

657 Jamin, YannNo conflicts

658 Witney, TimothyNo conflicts

659 Glunde, KristineNo conflicts

660 Medarova, ZdravkaNo conflicts

661 Ungersma, SharonGenentech, Inc.,Employment

662 Mata, JaimeNo conflicts

663 Hwang, YuyingAmgen, Ownership interest, Employment

664 Walker–Samuel, Simon, No conflicts

665 Reichardt, WilfriedNo conflicts

666 Liu, FengNo conflicts

667 Takahashi, EmiNo conflicts

668 Yang, JinzhongNo conflicts

669 Cheung, MatthewNo conflicts

670 Lau, Ho–faiNo conflicts

671 Gupta, RakeshNo conflicts

672 Guizard, NicolasNo conflicts

673 Muftuler, LNo conflicts

674 Kunz, NicolasNo conflicts

675 Wang, Wen–TungNo conflicts

676 Zotev, VadimNo conflicts

677 Banerjee Snyder,Modhurin, No conflicts

678 Hwang, DennisNo conflicts

679 Zhang, XiaoliangNo conflicts

680 Sipilä, PekkaNo conflicts

Declaration of Relevant Financial Relationships

681 Hoult, DavidNo conflicts

682 Wei, JuanNo conflicts

683 Shen, GaryNo conflicts

684 Ullmann, PeterBruker Biospin,Employment

685 Erickson, MatthewNo conflicts

686 Kreis, RolandNo conflicts

687 Gambarota, GiulioNo conflicts

688 Choi, ChanghoNo conflicts

689 Thakur, SunithaNo conflicts

690 Terpstra, MelissaNo conflicts

691 Frias–Martinez, En-rique, No conflicts

692 Maudsley, AndrewNo conflicts

693 Mangia, SilviaNo conflicts

694 Xin, LijingNo conflicts

695 Marro, KennethNo conflicts

696 Markl, MichaelNo conflicts

697 Rutz, AndreaNo conflicts

698 Rüssel, IrisNo conflicts

699 Abd–Elmoniem, Khaled, No conflicts

700 Aksit, PelinGeneral Electric,Employment

701 Fung, MaggieGeneral Electric,Employment

702 Basha, TamerNo conflicts

703 Foell, DanielaNo conflicts

704 Staehle, FelixNo conflicts

705 Elgeti, ThomasNo conflicts

706 Yokoo, TakeshiNo conflicts

707 Gard, CatherineNo conflicts

708 Altbach, MariaNo conflicts

709 Yu, HuanzhouGeneral Electric,Employment

710 Reeder, ScottGeneral Electric,Consulting fee

711 Sugay, SebastianNo conflicts

712 Cavassila, SophieNo conflicts

713 Hussain, HeroNo conflicts

714 van Werven, JochemNo conflicts

715 Bydder, MarkGeneral Electric,Employment

716 Wijnen, JannieNo conflicts

717 Khayal, InasNo conflicts

718 Galbán, CraigNo conflicts

719 Kumar, MohanrajaNo conflicts

720 Gibbs–Strauss,Summer, No conflicts

721 Berman, JeffreyNo conflicts

722 Chen, Poe–JouNo conflicts

723 Bian, WeiNo conflicts

724 Thulborn, KeithNo conflicts

725 Julià–Sapé, MargaridaNo conflicts

726 Çukur, TolgaNo conflicts

727 Priest, AndrewNo conflicts

728 Langham, MichaelNo conflicts

729 Wong, PaulineNo conflicts

730 Xu, JianNo conflicts

731 Masui, TakayukiGeneral Electric,unspecified relationship

732 Edelman, RobertSiemens, Research port

733 Johnson, KevinNo conflicts

734 Wang, JinnanNo conflicts

735 Piccirelli, MarcoNo conflicts

736 Piccirelli, MarcoNo conflicts

737 Fiorentino, NiccoloNo conflicts

738 Chung, ChristineNo conflicts

739 Du, JiangNo conflicts

740 Stanley, DavidGeneral Electric,Employment

741 Handley, TaylorNo conflicts

742 Barral, JoëlleNo conflicts

743 Carpenter, R.No conflicts

744 Goerke, UteNo conflicts

745 Notohamiprodjo, MikeNo conflicts

746 Robinson, SimonNo conflicts

747 Bianciardi, MartaNo conflicts

748 D’Andrea, JolynNo conflicts

749 Ma, LiangsuoNo conflicts

750 Kannurpatti, SridharNo conflicts

751 Rack–Gomer, AnnaNo conflicts

752 Kim, YoungNo conflicts

753 Lu, HanbingNo conflicts

754 Tu, YeNo conflicts

755 Liu, XiaoNo conflicts

756 Huo, DonglaiNo conflicts

757 Holdsworth, SamanthaNo conflicts

758 Sarlls, JoelleNo conflicts

759 Ye, YongquanNo conflicts

760 Saritas, EmineNo conflicts

761 Chu, RenxinNo conflicts

762 Kiruluta, AndrewNo conflicts

763 Komlosh, MichalNo conflicts

764 Koch, MartinNo conflicts

765 Avram, AlexandruNo conflicts

766 Reddick, WilburnNo conflicts

767 Koutcher, JasonNo conflicts

768 Arias–Mendoza, FernandoNo conflicts

769 Kim, SungheonNo conflicts

770 Baek, Hyeon–ManNo conflicts

771 Martincich, LauraNo conflicts

772 van Laarhoven,Hanneke, No conflicts

773 Padhani, AnwarNo conflicts

774 Hou, Bob, No conflicts

775 Koh, Dow–MuNo conflicts

776 Andronesi, OvidiuNo conflicts

777 Henning, AnkeNo conflicts

778 Boumezbeur, FawziNo conflicts

779 Xu, Su, No conflicts

780 Klomp, DennisNo conflicts

781 Panek, RafalNo conflicts

782 Kreis, RolandNo conflicts

783 Li, ShizheNo conflicts

784 Boumezbeur, FawziNo conflicts

785 Choi, In–YoungNo conflicts

786 Schultz, GerritNo conflicts

787 Chen, WeitianNo conflicts

788 Mitsouras, DimitrisNo conflicts

789 Chen, Nan–kueiGlaxo SmithKline, Research support

790 Wiesinger, FlorianGeneral Electric,Employment

791 Chen, WeitianNo conflicts

792 Sümbül, UygarNo conflicts

793 Jung, HongNo conflicts

794 Odille, FreddyNo conflicts

795 Schmitter, SarahNo conflicts

796 Aoki, IchioNo conflicts

797 Ackerstaff, EllenNo conflicts

798 Chertok, BeataNo conflicts

799 Schmieder, AnneKereos, Ownership interest Philips, Employment

800 Kadayakkara, DeepakNo conflicts

801 Aime, SilvioBracco, Consulting fee

802 Waters, EmilyNo conflicts

803 Jin, AlbertNo conflicts

804 Yamada, MayumiNo conflicts

805 Bernsen, MoniqueNo conflicts

806 Gonzalez–Lara, LauraNo conflicts

807 Duhamel, GuillaumeNo conflicts

808 Schepkin, VictorNo conflicts

809 Marques, JoséNo conflicts

810 Barazany, DanielNo conflicts

811 Bock, NicholasNo conflicts

812 Lin, Chien–YuanNo conflicts

813 Vorisek, IvanNo conflicts

814 Lerch, JasonNo conflicts

815 Blumenfeld–Katzir, Tamar, No conflicts

816 Krishnamurthy,Ramkumar, No conflicts

817 Muthurangu, VIvekNo conflicts

818 Maier, CorinnaSiemens, Unspecifiedrelationship

819 Kellman, PeterNo conflicts

Declaration of Relevant Financial Relationships

Declaration of Relevant Financial Relationships

820 Groves, AlanNo conflicts

821 de Rochefort, LudovicNo conflicts

822 Haacke, EwartNo conflicts

823 Kellman, PeterNo conflicts

824 Karaus, AlexanderNo conflicts

825 Fan, ZhaoyangNo conflicts

829 Sharp, JonathanNo conflicts

830 Sacolick, LauraNo conflicts

831 Bosshard, JohnNo conflicts

832 Çukur, TolgaNo conflicts

833 Coolen, BramNo conflicts

834 Nielsen, Jon–FredrikNo conflicts

835 Lee, JonghoNo conflicts

836 Saranathan, Mano-jkumar, General Electric, Employment

837 Busse, Reed, General Electric, Employment

838 Lu, WenmiaoNo conflicts

839 Hagmann, PatricNo conflicts

840 Gong, GaolangNo conflicts

841 Bogaert, AuroreNo conflicts

842 Blumenfeld–Katzir, Tamar, No conflicts

843 Sasson, EfratNo conflicts

844 Granziera, CristinaNo conflicts

845 Upadhyay, JayminNo conflicts

846 Benner, ThomasBayer Healthcare/Bayer Schering, Consulting fee,

847 Oishi, KenichiPhilips, research port, Honoraria,

848 Geng, XiujuanNo conflicts

849 Chen, YufenNo conflicts

850 Zappe, Anne–CatherinNo conflicts

851 He, XiangNo conflicts

852 Xu, FengNo conflicts

853 Mellon, EricNo conflicts

854 Liau, JoyNo conflicts

855 Lu, HanzhangNo conflicts

856 Magon, StefanoNo conflicts

857 Drescher, KnutNo conflicts

858 Winkelmann, StefaniePhilips, Employment

859 De Silva, SonaliNo conflicts

860 Cohn, BradNo conflicts

861 Iman, RahwaNo conflicts

862 Hull, WilliamBruker Biospin,Consulting fee

863 Grande, SvevaNo conflicts

864 Bezabeh, TedrosNo conflicts

865 Valverde–Saubí, DanielNo conflicts

866 Cui, Min–HuiNo conflicts

867 Machann, JürgenNo conflicts

868 Vasu, VimalNo conflicts

869 Sleigh, AlisonNo conflicts

870 Stephenson, MaryNo conflicts

871 Brown, MarkNo conflicts

872 Yerby, BrittanyNovartis, Ownershipinterest, Employment

873 Hollingsworth, KierenNo conflicts

874 Antkowiak, PatrickNo conflicts

875 Ith, MichaelNo conflicts

876 Zhong, KaiNo conflicts

877 Schäfer, AndreasNo conflicts

878 Ge, YulinNo conflicts

879 Rauscher, AlexanderNo conflicts

880 Helms, GuntherNo conflicts

881 Fukunaga, MasakiNo conflicts

882 Dawe, RobertNo conflicts

883 Oros–Peusquens, Ana–Maria, No conflicts

885 Li, Tie–QiangNo conflicts

886 Schroeder, MarieGeneral Electric, Grant Funding

887 Merritt, MatthewNo conflicts

888 Chen, AlbertNo conflicts

889 Gallagher, FerdiaGeneral Electric, Provided research equipment

890 Yen, Yi–FenNo conflicts

891 Zierhut, MatthewNo conflicts

892 Rose Jensen, PernilleGeneral Electric, Financial port Imagnia AB, Owner-ship interest, Employment

893 Jamin, YannNo conflicts

894 Gabellieri, CristinaNo conflicts

895 Evans, AndreaNo conflicts

896 Krueger, SaschaPhilips, Employment

897 Zanchi, MartaNo conflicts

898 Venook, RossNo conflicts

899 Nordbeck, PeterNo conflicts

900 Langman, DeborahNo conflicts

901 Kanal, EmanualMedtronics, Consulting fee

902 Strick, DebraNo conflicts

903 Bitz, AndreasNo conflicts

904 Kocaturk, OzgurNo conflicts

905 Kraemer, NilsNo conflicts

Jeffry Alger, Ph.D.Talissa Altes, M.D..Carles Arús, Ph.D.Peter A. Bandettini, Ph.D.Georg Bongartz, M.D., (Past Chair)Peter Börnert, Ph.D.Jean H. Brittain, Ph.D.Fernando Calamante, Ph.D.Alan Connelly, Ph.D.Nicola De Stefano, M.D.Xavier G. Golay, Ph.D.Penny A. Gowland, Ph.D.P. Ellen Grant, M.D., MScMark A. Griswold, Ph.D.Oliver Heid, M.D.Claudia Hillenbrand, Ph.D.Juerg Hodler, M.D.N. R. Jagannathan, Ph.D.

Mark Jenkinson, Ph.D.Derek K. Jones, Ph.D.Martin O. Leach, Ph.D.Vivian S. Lee, M.D., Ph.D. (ex officio)Debiao Li, Ph.D.Pia C. Maly Sundgren, M.D., Ph.D.Elmar Merkle, M.D.Timothy J. Mosher, M.D.Caron Murray, M.R.T.,(R)(MR)Jeffrey J. Neil, M.D., Ph.D.Klaas Nicolay, Ph.D.Douglas Noll, Ph.D.David G. Norris, Ph.D. (ex officio)Michael D. Phillips, M.D.Carlo Pierpaoli, Ph.D.James G. Pipe, Ph.D.John D. Port, M.D., Ph.D.Klaas Pruessman, Ph.D.

Markus Rudin, Ph.D.Stefan G. Ruehm, M.D., Ph.D.Henry Rusinek, Ph.D.Brian Rutt, Ph.D.Stefan Schoenberg, M.D.Greig C. Scott, Ph.D.Afonso Silva, Ph.D.Orlando Simonetti, Ph.D.Daniel Sodickson, M.D., Ph.D.Oliver Speck, Ph.D.Clare Tempany, M.D.Bernard Van Beers, M.D., Ph.D.Mark van Buchem, M.D., Ph.D.Daniel B. Vigneron, Ph.D.Lawrence L. Wald, Ph.D.Han Wen, Ph.D.Patrick Winter, Ph.D.

ISMRM Annual Meeting Program CommitteeKim Butts Pauly, Ph.D., Chair

Margaret A. Hall–Craggs, M.D., Vice Chair

Toronto!ISMRM 16th Scientific Meeting & Exhibition • SMRT 17th Scientific Annual Meeting

3-9 MAY 2008

ISMRM Staff

Roberta A. Kravitz, Executive Director

Jennifer Olson, Associate Executive Director

Allison Barbour, Electronic Communications Coordinator

Mariam Barzin, Director of Finance

Sandra Daudlin, Director of Meetings

Mary Day, Administrative Assistant

Martha de Giere, Accounting Coordinator

Robert Goldstein, Director of Education

Jennie Jordan, SMRT Coordinator

Mary Keydash, Director of Publications

Kristina King, Director of Membership and Study Groups

Stephanie Kollmeyer, Education Coordinator

Kailin Mardones, Registrar

Sally Moran, Director of Electronic Communications

Alli Novak, Meetings Coordinator

Meredith Prince, Membership & Study Group Coordinator