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Neuroradiology
Ted Passe, MDNeuroradiology
Mayo Clinic Rochester, MN
Objectives
• Imaging modalities in epilepsy• Anatomic – CT/MRI• Functional – MRS, SPECT, PET, fMRI, MSI, DTI
• Characteristic imaging findings in epilepsy• Infectious / Inflammatory• Mesial Temporal Sclerosis• Malformations of Cortical Development• Vascular malformations• Neoplastic
• Methods of improved lesion detection • Dedicated seizure protocol• Higher resolution 3T MRI / 7T MRI• Subspecialized image interpretation
What is CT?
• CT=computed tomography
• CT is an X-ray based system
• A tube rotates around the patient projecting X-rays through the patient from many angles
• A ring of X-ray detectors collects an image from each projection angle around the patient
• 1st generation CT scanners had 1 detector. Newer CT scanners have multiple detectors (16, 32, 64, 256+) which allow increased speed and resolution
History of CT
• Invented 1972 by engineer Godfrey Houndsfield
• EMI laboratories, England
• Nobel prize in Medicine 1979
• Knighted 1981
• Original axial CT image from a dedicated CT scanner circa 1975
• This image is a coarse 128 x 128 matrix
Godrey Hounsfield EMI Laboratories – 1st CAT Scanner
Godfrey Hounsfield with EMI scanner Volunteer in EMI scanner
EMI and The Beatles
• EMI, a British electronics and music company
• Better known as the record company for the Beatles
• $ to fund research into the development of the 1st CT scanner stemmed from $ from Beatles record sales
CT Revolutionized Neuroradiology
CT Then and Now
CT Images
• Cross sectional images are made up of "pixels" (picture elements). Each 2D pixel represents a 3D "voxel" (volume element) of tissue being imaged
• Smaller pixels → higher resolution (think HD TV)
• A pixel represents the ability of the atoms within the voxel to attenuate (decrease) an X-ray beam
• Contrast varies with density of tissue
• Bone/metal=bright white
• Muscle=gray
• Air=black
• Pathological processes are identified by alterations in anatomy and attenuation
Wooden Foreign Matter
• 18-yo female near to an explosion
• Wood fragment penetrated skull
Head CT Indications in Epilepsy
• Emergent imaging necessary• If MRI not available
• If MRI contraindicated
• To evaluate for calcium
• MRI remains much more sensitive than CT in epilepsy workup
What is MRI?
What is MRI?
• Click to edit Master text styles– Second level
• Third level– Fourth level
» Fifth level
• Patient in powerful magnetic field
• Protons align with the field
• Gradients and RF pulses create signal
• Reflected RF signal received by coils
• Computer processing used to create images in multiple planes
• Unlike CT or CR, no ionizing radiation
MRI Safety
• Static Magnetic Field: The powerful super-conducting magnetic field is the most dangerous aspect of MRI and is ALWAYS ON!!!
• External metal objects can become missiles
• Can turn off pacemakers or electrical devices
• Can dislodge/torque metal implants (eye, aneurysm clips)
• Can erase credit cards/magnetic cards
Wheelchair in Magnet
Oxygen Tank in Magnet
Phone and Selfie Stick in Magnet
MRI: Safety
• RF power deposition• Causes heating within the body
• Challenging issue at high field MRI as Specific Absorption Rate (SAR) proportional to square of Bo• RF deposition quadruples at 3T
• FDA SAR limit: 4 W/kg body and 3 W/kg head
• Limits pulse sequences (FSE - strong RF pulses)
• Neurostimulators are relatively contraindicated• Depth electrodes • Vagal nerve stimulators
RF-induced Burns at Cardiac Leads
VNS Safety
• Safety guidelines required for VNS as MRI can:• Induce heat in the VNS lead – tissue injury
• Change pulse generator settings or activate device
• MRI Protocol:• Transmit/receive coil only
• No scans with body coil or receive only coils
• Pulse generator output programmed to 0 mA before MRI and reprogrammed after MRI
• Static MRI field less than or equal to 3 Tesla
• SAR less than 1.3 W/kg
• Time – varying intensity: less than 10 Tesla/sec
ConventionalMRI
Sag T1
Ax FLAIR
Ax Diffusion Weighted
Image
Cor T2
Ax T2
“Standard Magnetic Resonance Imaging is Inadequate for Patients With Refractory Focal Epilepsy”
Sensitivity of lesion detection in medically refractory epilepsy:
1. 39% non-expert radiologist on standard MRI2. 50% experienced neuroradiologist (>3 yrs
epilepsy center) standard MRI → +11%3. 85% experienced neuroradiologist with focused
Epilepsy MRI → +46%
Note: most problems with under-detection, #1 MTS, #2 focal cortical dysplasia
Von Oertzen, et al. J Neurol Neurosurg Psychiatry. 2002.
Seizure Protocol
• Routine head• Sag T1 FLAIR, Ax T2 , Ax FLAIR, Ax DWI
• Cor Hi Res T2 FSE (3 mm) – Assess architectural distortion
• Cor FLAIR – Assess for increased signal
• Cor SPGR 3D volume –• Assess for hippocampal atrophy• Qualitative and/or quantitative
• GRE and/or SWI – Assess for chronic hemorrhage
• Double IR – Increased sensitivity for cortical dysplasia
• DTI - FA maps routine, tractography case by case
• Gadolinium for tumor, AVM or neurocutaneous syndromes
Advanced Imaging Techniques in Epilepsy
• A patient with Epilepsy may be classified as nonlesional for 2 reasons:
• 1) A lesion may not exist; that is, the structural abnormality that gives rise to seizures may be at the channel level or be spatially distributed in such a way that it would not be accurately termed a lesion, or
• 2) A lesion exists but is so subtle that standard clinical imaging is not sensitive enough to discriminate between the lesion and surrounding healthy brain tissue. As with any technology and disease, this definition is dynamic, as that future imaging techniques will be developed and new disease mechanisms will be discovered, making detection of the epileptogenic underlying abnormality an ever-changing target.
• Goal to move each patient from non-lesional to lesional epilepsy
Pardoe H, Kuzniecky R. Epilepsy Curr. 2014.
Hi Resolution 3D Volume MRI
3T (and now 7T) MRI
• FDA approved 3T MRI in 2001
• October 2017 – 1st FDA clinical MRI at Mayo Clinic
• 7 Tesla=140,000 X Earth’s magnetic field
• Boltzmann equation: S/N ~ Bo
• Other MR improvements – (not just 3T)• Coil technology
• Gradient technology
• Computing power
3T Superior to 1.5T in Epilepsy Evaluation
• Retrospective study of 25 epilepsy patients
• 3T correctly identified structural lesions in 88% of epilepsy patients vs. 74% at 1.5T
• 3T also had significantly better:• Lesion conspicuity
• Tissue contrast
Phal PM, et al. AJR Am J Roentgenol. 2008.
1.5T SPGR 3T SPGR
MTS 1.5T vs. 3T
MTS 1.5T vs. 3T
1.5T - Hi Res T2 3T – Hi Res T2
7T vs 3T
7T Sag DIR 3T Sag DIR
Double Inversion Recovery (DIR)
• DIR significantly improves conspicuity of epileptogenic lesions compared to FLAIR1
• DIR demonstrates increased sensitivity to cortical dysplasia and is complementary to MPRAGE.2
1Kattumannarkudi R, et al. RSNA. 2014. Abstract 429; 2Wong-Kisiel LC, et al. Pediatr Neurol. 2016.
Double Inversion Recovery (DIR)
Sag DIR (7T) Sag T1 MPRAGE (7T)
Brief Summary
• Structural imaging • MRI better than CT
• Improve lesion detection via:• Use dedicated seizure protocol
• Use 3T or 7T MRI if available
• Review by experienced neuroradiologist
Epilepsy: Pathologic Substrates
• Infectious/inflammatory
• Mesial Temporal Sclerosis
• Malformations of cortical development
• Vascular malformations
• Neoplastic
26-yo Male: New Onset Seizure
What is the imaging diagnosis?
Neurocysticercosis
• #1 cause of adult-onset seizure worldwide
• Dissemination of the pork tapeworm larva
• Increasing incidence in US
• CT – classic calcified scolex
• Transient worsening with antiparasitic tx• Vasogenic edema
Disseminated Neurocysticercosis
Racemose Cysticercosis
39-yo Female: Seizure, Confused
39-yo Female: Seizure and ConfusedMRI 4 Days Later
FLAIR Diffusion Gradient Echo
MRI 2 Days Later
FLAIR FLAIR Cor T2
Herpes Encephalitis – Adult
• #1 cause of sporadic viral encephalitis
• Overall rare: 3 cases/100,000/year
• Adults – HSV-1
• Retrograde spread of latent virus from a peripheral ganglion (trigeminal/olfactory)
• Involves limbic system, temporal and frontal lobes
• Untreated 70% mortality
• Treatment: IV acyclovir
• Treated: 40% recover w/o deficit; 30% mortality
Ax T2 Ax T2
70-yo Female with Memory Problems and Seizure
FLAIR FLAIR
70-yo Female with Memory Problems and Seizure
Diffusion Diffusion
70-yo Female with Memory Problems and Seizure
Creutzfeldt – Jakob Disease
T2 FLAIR Diffusion
Creutzfeldt – Jakob Disease
• Progressively fatal spongiform encephalopathy
• Prion protein – causative agent
• Rare: 1/million/year
• Rapidly progressive dementia, myoclonic jerks
• MR: increased signal caudate, putamen, cortex
• DWI>FLAIR>T2 sensitivity
Confusion While Tapering AEDs
Confusion While Tapering AEDs
Sag T1 Sag FLAIR
Transient Splenium Lesions /Cytotoxic Lesions of the Corpus Callosum
(CLOCCs)• Pathophysiology of this lesion in the SCC in patients with epilepsy or on
AEDs remains unknown
• Postulated to be due to increased glutamate causing influx of intracellular water preferential to splenium due to high density of oligodendrocytes with glutamate receptors
• Lesions of the SCC on MRI appear to be a benign, rare finding, not requiring specific treatment, although follow-up MRI may be reassuring
• Associated with seizures and classically the rapid taper of AEDs may be a factor contributing the development of a lesion in the SCC in patients on AEDs
• Association with Influenza, Migraine with Aura, etc…
• Typically asymptomatic and transient / reversible on imaging in 1 week to 1 month
Transient Splenium Lesions
Ovoid or boomerang sign
Hippocampal Diffusion Abnormality
Recent or ongoing seizure activity / Status Epilepticus
Pulvinar Abnormality 17 / 224 seizure patients – all had status
MRI abnormality of the pulvinar in patients with status epilepticus -
Ohe Y, et al, J Neuroradiol. 2014.
Sudden Onset Left Sided Numbness and Confusion
PCA Occlusion with Acute Infarcts
Autoimmune Epilepsy
• Frequent cause of epilepsy of unknown etiology
• Paraneoplastic and non-paraneoplastic groups
• Common neural specific antibodies LGI1, NMDA-R, Gad65 IgG
• Potentially treatable with immunotherapy
• Limbic system (limbic encaphalitis) most common but cortex, cerebellum and basal ganglia all can be involved
• Acute phase – Edema / hypermetabolic PET
• Chronic phase – gliosis (MTS) / hypometabolic PET
Fang Z, et al. Front Immunol. 2017; Kelley BP, et al. AJNR Am J Neuroradiol. 2017.
Autoimmune Epilepsy
• 64 year old Myasthenia Gravis
• New cognitive decline
• Subclinical left temporal lobe seizures on EEG
MRI
FDG-PET
30-yo with Partial Complex Seizures; Right Temporal Lobe Abnormal EEG
3T Cor SPGR 3T Cor Hi Res T2
Mesial Temporal Sclerosis (MTS)
• Primary findings: hippocampal atrophy and gliosis• Atrophy on Cor SPGR T1
• Increased FLAIR signal• T2 increased signal and
architectural distortion
• Secondary findings• Enlargement of ipsilateral
temporal horn/choroidal fissure
• Thinning of fornix
• Atrophy of mammilary body• Loss of normal interdigitations of
hippocampal head
Dual Pathology – 5%-20% of MTS Patients Have an Extra-hippocampal Lesion
Post-traumatic encephalomalaciaand gliosis
Left MTS
MTS Dual Pathology
MTS Dual Pathology
Temporal Encephalocele - 1
• Temporal encephaloceles increasingly visualized during neuroimaging assessment of patients with refractory epilepsy and could indicate potential seizure focus.
• 52 of 434 cases reviewed by expert (only 7 initially reported)
• 3T more sensitive
• Hi resolution T2 weighted sequences most sensitive
• Associated with findings of idiopathic intracranial hypertension
• Associated with temporal lobe seizures
Campbell AM, et al. AJNR J Neuroradiol. 2018.
Temporal Encephalocele - 2
• 8 year study – 23 patients with encephalocele
• 0.3% first time seizure MRI
• 1.9% refractory epilepsy cases
• 12 went to surgery, 9 seizure free, 3 improved
Saavalainen, T et al. Neurology. 2015.
Temporal Encephalocele
Malformations of Cortical Development
Malformations of Cortical Development
• Common finding in intractable epilepsy
• 3 categories of MCD depending on stage of brain maturation when insult occurred
1. Neuronal and glial proliferation (<10 wks)• Microcephaly, hemimegalencephaly, Tuberous Sclerosis
2. Neuronal migration (10-20 wks)• Heterotopias – nodular, band heterotopia, lissencephaly
3. Late cortical organization (>20 wks)• Polymicrogyria, schizencephaly, cortical dysplasia
11-yo Boy with Seizure Disorder
Tuberous Sclerosis
• Subependymal nodules• Glial/neuronal cells, often
calcify
• Cortical/subcortical tubers• Balloon cell migrational
anomaly• Triangle shape, apex toward
ventricle• T2 hyperintensity radiates
toward ventricle
• Subependymal Giant Cell Astrocytoma (SEGA)• Enhancing nodule at foramen
of Monro• Can cause obstructive
hydrocephalus
Nodular Grey Matter Heterotopia
• Subependymal and/or subcortical WM
• Round/oval nodules
• Follow grey matter on all MR pulse sequences
• If bilateral, associated with cognitive delay
• Seizure-free outcome after temporal lobe epilepsy is poor, if nodule not resected
Nodular Gray Matter Heterotopia –3T
25-yo female with a seizure disorder
Chronic Seizures – 1.5T vs. 3T MRI
1.5T 3T
Chronic Seizures – 1.5T vs. 3T MRI
1.5T 3T
Agyria-Pachygyria-Band Spectrum of Cortical Malformations
• Spectrum of disorders caused by deficient neuronal migration during embryogenesis.
• Mutation in LIS1 gene and DCX gene • LIS1 mutation – post to ant gradient of abnormality
• DCX mutation – ant to post gradient of abnormality
Dobyns WB, Das S. LIS1-Associated Lissencephaly/Subcortical Band Heterotopia. 2009 Mar 3 [Updated 2014 Aug 14]. In: Pagon RA, Adam MP, Ardinger HH, et al., editors. GeneReviews® [Internet]. Seattle (WA):
University of Washington, Seattle; 1993-2015.
Lissencephaly (Smooth Brain)
• Reduced sulcation – decreased number + depth of sulci
• Classic “figure 8” appearance
• Interfere with translocation of migrating neurons along radial glial cells to cortex
• Mutation in LIS1 gene and DCX gene • LIS1 mutation – parieto-occipital
region• DCX mutation – frontal lobes
4-yo female – seizure disorder
Subcortical Band Heterotopia
• SBH due to milder mutation of LIS1 or DCX• Frontal – DCX
• Parieto-occipital – LIS1
• Thick or thin band of gray matter in white matter parallel to normal appearing cortex
• Poor surgical outcome
6-yo female – dev delay + seizures
Subcortical Band Heterotopia
FLAIR T1 T2
18-yo female with chronic seizure disorder
Subtle Case Example
• 24 year old female with drug resistant epilepsy, onset at age 21, staring spells initially progressing to tonic/clonic seizures.
• Outside MRI read as normal.
3T MRI
FFLAIR T2
3T MRI
DIR T1-MPRAGE
3T vs 7T
3T 7T
25 Year Old Male – Chronic Seizures
LIS1 associated band heterotopia
Focal Cortical Dysplasia
• Abnormal cortical lamination
• Blurring grey – white matter junction
• Increased T2/FLAIR signal
• Cortical thickening on 3 contiguous slices
• Can be subtle or not visible on MRI
13-yo female with seizure disorder
FA Map T2
Polymicrogyria
• Malformation of late cortical organization
• Excessive small gyri and sulci• Focal – limited or extensive• Multifocal• Bilateral and symmetric vs.
asymmetric• Diffuse
• MRI – bumpy irregular cortical surface and subcortical junction
Polymicrogyria 1999 vs 2007
Schizencephaly
• CSF cleft from subarachnoid space to lateral ventricle lined by dysplastic cortex/polymicrogyria
• Closed lip vs. open lip – open lip worse prognosis
• 1/3 bilateral (worse prognosis)
• Imaging DDX vs. porencephaly(no gray matter lining)
• Small dimple in ventricle wall
Intractable Epilepsy
Cavernous Malformations
• Most common vascular malformation associated with epilepsy
• Identify with MRI
• Get GRE to assess for other lesions
• Can be hereditary
• Can be symptomatic due to bleed
Chronic Hemorrhage – GRE Blooming
55-yo female with seizures
Susceptibility Weighted Imaging -SWI
SWI GRE FSE – T2
MRI – AVM
13-yo Female – Seizures
13-yo Female – Seizures
13-yo Female – Seizures
Sturge Weber Syndrome
• AKA encephalotrigeminal angiomatosis
• Port wine stain V1 and V2 distribution • Orbit and forehead region
• Ipsilateral Leptomeningeal Angiomatosis• Abnormal venous drainage pattern
• Typically parietooccipital region
• Ipsilateral choroid plexus enlargement
Neoplasms
• Source in 20% of intractable epilepsy
• Typically low grade
• Typically cortical location
• 2/3 temporal lobe
Common Epileptogenic Tumors
• Low grade astrocytoma• Fibrillary vs. pilocytic
• Oligodengroglioma
• Ganglioglioma
• Dysembryoplastic Neuroepithelial Tumor (DNET)
• Pleomorphic Xanthoastrocytoma (PXA)
32-yo Female – Long History of Seizures; Prior Head CT Report Normal
Ganglioglioma
19-yo Male: New-onset Seizure
Cor SPGR T1 Cor FLAIR Cor Hi Res T2
53-yo Male: New-onset Seizures
Path = Glioblastoma
58-yo Female: New-onset Seizure
Metastasis
4-yo Female: New-onset Seizure
Stealth Localization MRI
• Initial DDX• Dysplastic changes
• Low grade neoplasm
• Localization MRI• Signal gone…
• Edema due to seizure activity and/or encephalitis
Functional Imaging Modalities
• MRI-based
• MR spectroscopy
• Functional MRI
• Diffusion Tensor Imaging/Tractography
• Nuclear medicine
• PET
• SPECT
• Magnetoencephalography/Magnetic Source Imaging
MR Spectroscopy
• MR Imaging and MR Spectroscopy differ only in the manner in which the data are processed and presented
• MRS obtains metabolite peaks rather than images
• Allows non-invasive sampling of brain’s chemical environment
• Single voxel and multivoxel techniques
MR Spectroscopy in Epilepsy
• Primary use in TLE
• Decreased NAA (a putative neuronal cell marker) due to neuronal loss
• Increase choline – gliosis
• Best marker – NAA/(Cho + Cr) ratio
• 90% correct lateralization in TLE
• 20%-40% bilateral MRS abnormality• Prelim evidence suggests higher likelihood of surgical
failure in TLE bilateral
Normal Single Voxel Proton Spectra
Choline: 3.24 ppm Creatine: 3.02 ppm NAA: 2.02 ppm
MTS
MTS Spectroscopy
Right: Mild decrease NAA Left: Moderate decrease NAA Normal Control
Right Temporal Lobe Left Temporal Lobe
FDG PET
• FDG – evaluates glucose metabolism
• TLE: interictal hypometabolism in >85%
• Useful if MRI + EEG are discordant or if normal MRI
• Not needed if EEG and MRI match
• Less useful in frontal lobe epilepsy
• Co-registration with MRI
FDG=Fludeoxyglucose (18F)
Hybrid PET/MRI
• Currently typically co-register to MRI
• Hybrid PET-MRI – New combination modality• Initial experience: 29 patients with epilepsy surgery*
• 24/29 – No difference with PET/MRI
• 4 new MRI lesions with concordant PET
• 1 new PET abnormality
• All 5 new lesions were clinically significant
Shin HW, et al. Seizure. 2015.
FDG PET: Temporal Lobe Epilepsy
Boca Radiology Group
FDG PET: Temporal Lobe Epilepsy
New England PET Imaging
Single-photon Emission Computerized Tomography (SPECT)
• Technetium 99m – Measures cerebral blood flow• Interictal – hypoperfusion
• Ictal – hyperperfusion – 90% localize in TLE
• Uses – similar to PET• Discordant MRI and EEG
• Problems• Not useful if multiple seizure onset
• False lateralization if delayed injection (>20 secs)
Ictal SPECT
A. Interictal PET hypometabolismB. Ictal SPECT hyperperfusion
SISCOM (Subtraction Ictal SPECT CO-registered to MRI)
• Sensitivity of ictal SPECT increased significantly when ictal and interictal images are subtracted
• Subtracted image superimposed on Hi-Res MRI
• Further increases sensitivity and specificity
• Surgical outcomes under study
SISCOM
Mayo Foundation
Functional MRI
• BOLD effect (Blood Oxygen Level Dependent): changes in venous blood oxygenation accompany changes in regional brain activity
• Cortical activation → increased blood flow >O2 utilization →increase in oxyhemoglobin
• T2 and T2*-weighted MRI are sensitive to changes in blood oxygenation (oxyhemoglobin vs. deoxyhemoglobin)
• Paramagnetic affects of oxyhemoglobin→ decreased signal on T2* MR sequence
• Subtle changes (<2% signal change at 1.5T, greater at 3T)• Statistical comparison of signal in rest and active paradigms
targeting specific brain regions• Allows detection of areas of brain activated by a specific task• Primary role → surgical localization
Functional MRI – Paradigms
• Motor activation (finger tapping)
• Sensory activation
• Visual activity
• Auditory stimulation
• Language paradigms
• Memory tasks
fMRI – On-Off Paradigm
Columbia fMRI
Motor Activation
Language Paradigms
fMRI – Surgical Planning
What is the source of the Mississippi River?
A. Lake Menominee
B. Lake Itasca
C. Lake Minnehaha
D. Lake Okeechobee
Where Does Lake Itasca Get Its Name?
verITAS CAput“True Head”
of the Mississippi River
Diffusion MRI
• Diffusion MRI is a specific pulse sequence that measures the micro-molecular translational motion of water molecules (Brownian motion) to obtain information on the microscopic behavior of the tissues
• Clinical applications• Stroke imaging
• Diffusion Tensor Imaging
• White Matter Tractography
Diffusion MRI – Complex Math
Diffusion MRI – Basics
• Gradients with equal amplitude but opposite polarity are applied over a given interval
• Gradients of sufficiently high amplitude make the sequence sensitive to motion at the microscopic level
• During the typical imaging time of 50 msec, the average water molecule diffuses 10 microns
• Stationary tissue will be dephased and rephased equally, whereas spins which have moved during the interval will suffer a net dephasing and signal loss
• Thus, protons that diffuse the farthest will have the greatest loss of signal
Diffusion MRI in Stroke Imaging
• DWI is very sensitive to acute infarcts
• Revolutionized stroke imaging
• Hypothesis – as Na/K/ATPase pump fails, cells swell • Resultant restricted diffusion
• DWI – lightbulb bright infarcts• DWI drawback: both T2 + diffusion components
• ADC maps (apparent diffusion coeffecient) show the mean diffusion within each voxel (decreased diffusion → decreased signal)
CT
• Acute onset
• Right sided weakness
• Right facial droop
• Slurred speech
Diffusion vs Conventional MRI
FLAIR Diffusion
Diffusion Tensor Imaging
• Diffusion imaging measures free motion of H2O
• Ex: restricted diffusion in acute infarcts
• Diffusion Tensor Imaging measures anisotropy (the degree of directionality to H2O motion)
• Allows mapping of white matter tracts (axons)
• Disrupted vs. displaced in tumor surgery planning
• Subtle cortical dysplasia or migrational anomaly
In-vivo Water Diffusion
• Click to edit Master text styles– Second level
• Third level– Fourth level
» Fifth level
• Diffusion of water is hindered by cell membranes, myelin
• Diffusion of water• Greatest in CSF
• Reduced in gray matter and isotropic
• Reduced in white matter but anisotropic
Diffusion in Biological Tissue
• Motion of water through tissue• Faster in some directions than others
Kleenex newspaper
• Anisotropy: diffusion rate depends on direction
isotropic anisotropic
Gordon Kindlmann - Scientific Computing and Imaging Institute, University of Utah
Independent Verification
Direction Encoded FA Maps
White Matter Tractography: Fiber Mapping
Corpus Callosum – Splenium Fibers
Corticospinal Tract ROIs
Corticospinal Tracts
19-yo Male with HAGrade III Anaplastic Oligoastrocytoma
T2 T1 + Gad Cor T2
DTI Fiber Mapping
Left-Sided Weakness
Bx: Grade III Anaplastic Astrocytoma
Tractography: Tumor Surrounds Corticospinal Tracts
Pre-op and Intra-op Integration
• MSI • Language
• Sensory
• Motor
• DTI/Fiber Mapping• Arcuate fasciculus
• Corticospinal tracts
• Optic radiations
• Intra-op MRI Integration
Multimodal Surgical Planning with Intra-operative MRI
• 14-yo with seizure disorder
• Prior biopsy diagnosis: • Dysembryoneoplastic Neuroepithelial Tumor (DNET)
Conventional MRI – DNET
DNET Follow-up: Growth of Central Enhancing Nodule
12/19/07 2/26/08
DTI/Fiber Mapping
Arcuate Fasciculus Corticospinal tracts
Neuro-Navigation Integration
Intra-op Imaging and Stereotactic Guidance
Intra-op #1 Ax T2 Intra-op Final T2 Intra-op Final T1 + gad
90% tumor resection, 100% enhancing nodule resection, no deficits post-op
Conclusions
• Imaging modalities in epilepsy• Anatomic – CT/MRI• Functional – fMRI, MRS, SPECT, PET, and MSI
• Imaging characteristics of common epilepsy pathology
• Methods of improved lesion detection • Subspecialized image interpretation• Dedicated seizure protocol • High resolution 3T MRI
• Multimodality integration • Pre-op planning • Intra-op navigation