Scientific Exhibitions 567

Neuroradiology

Neuroradiology

SE 09 NR-01 The 100 most-cited articles in neuroimaging: a bibliometric analysisHye Jeong Kim1, Dae Young Yoon2, Eun Soo Kim3, Kwanseop Lee3 1Kangnam Sacred Heart Hospital, 2Kangdong Sacred Heart Hospital, 3Hallym University Sacred Heart Hospital, Hallym University, Korea. evee0914@chollian.net

PURPOSE: The number of citations that an article has received reflects its impact in the scientific community. The purpose of our study was to identify and characterize the 100 most-cited articles in neuroimaging.MATERIALS AND METHODS: We selected the 669 journals that were considered journals potentially publishing neuroimaging articles based on the database of Journal Citation Reports. The Web of Science search tools were used to identify the 100 most-cited articles relevant to neuroimaging within selected journals. The following information was recorded for each article: publication year, journal title, journal category, impact factor, number of citations, number of citations per year, authorship, department, institution, country, article type, imaging technique used, and topic.RESULTS: The 100 most-cited articles in neuroimaging were published between 1980 and 2012, with 1995-2004 producing 69 articles. Citations ranged from 4384-673 and citations per year ranged from 313.1-24.9. The majority of articles were published in radiology/imaging journals (n = 75), originated in the United States (n = 58), were original articles (n = 63), used MRI as imaging modality (n = 85), and dealt with imaging technique (n = 45). Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, John Radcliffe Hospital (n = 10) was the leading institutions and Karl J. Friston (n = 11) was the most prolific author.CONCLUSION: Our study presents a detailed list and analysis of the 100 most-cited articles in the field of neuroimaging, which provides an insight into historical developments and allows for recognition of important advances in this field.

SE 09 NR-02 Acute necrotizing encephalopathy of childhood (ANEC) secondary to RSV infection: a case report Sidney Ching Liang Ong1, Nur Azidawati Ab Halim2, Anita Sahal2, Yuan Hwen Liew2 1International Medical University, 2Hospital Tuanku Ja'afar, Malaysia. sidney_ong@yahoo.co.uk

Acute necrotizing encephalopathy of childhood (ANEC) is an uncommon disease with characteristic clinical and imaging findings. Cases are seen sporadically in the Far East and patients often have rapid clinical deterioration with some progressing to death. Various etiologies have been proposed but to our knowledge, there is no reported case of ANEC secondary to RSV infection.An 8-month-old male presented with fever and diarrhea for 2 days. He was initiallytreated as acute gastroenteritis at a district hospital but soon developed multipleepisodes of tonic seizure. Initial NECT brain showed bilateral symmetrical thalamic and pontine hypodensities. MRI brain confirmed CT findings but showed more extensive involvements at posterior limbof internal capsules, caudate nuclei, tegmentum, cerebellar white matter and part of left parietal lobe. Nasopharyngeal aspirate immunofluorescence (NPAIF)was positivefor RSV. He completed a course of IV Ribavirin and received supportive oxygen therapywhile IVIG and ceftriaxone were given empirically. Child was discharged well withantiepileptics after 6 weeks of treatment but was briefly admitted again forbreakthrough seizure due to viral fever. Repeated outpatient MRI brain 2 months latershowed generalized brain atrophy with late subacute hemorrhages at bilateral thalami. The previously seen abnormal white matter signals have largely resolved.In conclusion, early recognition and diagnosis of this poorly understood but well-documented condition will facilitate potential lifesaving treatments.

568 KCR 2016

Neuroradiology

SE 09 NR-03Radiology resident interpretations of diffusion-weighted MR imaging in the emergency department: is the diagnostic performance influenced by level of residency training?Seung Jin Kim1, Sungjae Lee1, Hye Jin Baek1, Hyun Kyung Jung1, Jin Il Moon2, Soo Buem Cho2, Bo Hwa Choi2, Kyungsoo Bae2, Kyung Nyeo Jeon2, Dae Seob Choi2 1Inje University Haeundae Paik Hospital, 2Gyeongsang National University Changwon Hospital, Korea. sartre81@gmail.com

PURPOSE: To evaluate the diagnostic performance of radiology residents interpretations for diffusion-weighted MR imaging (DWI) in the emergency department at different levels of residency training.MATERIALS AND METHODS: A total 160 patients who underwent DWI with acute neurologic symptoms were included in this retrospective study with Institutional Review Board approval. Four radiology residents with different training years and one attending neuroradiologist independently assessed the results of DWI. Discordances between the results of residents and attending neuroradiologist were classified as followings; false-positive (FP) and false-negative (FN). We also evaluated a diagnostic performance of four residents according to the reference standard.RESULTS: Overall, the concordance rate was 84.8% with 15.2% of overall discordance rate. There were 83 FN results. The most common misses were acute focal infarction (n = 13), extraaxial hemorrhages (n = 18), small vessel disease (n = 34), diffuse axonal injury (n = 7), solitary mass (n = 6), posterior reversible encephalopathy syndrome (n = 2), and postictal change

(n = 3). There were 14 FP results which were interpreted as hemorrhage and acute infarction. The 4th-year resident showed the highest diagnostic performance, and the level of training had a significant influence on the rates of concordance (p < 0.05). Interobserver reliability was good between the interpretations of residents and the final interpretations of attending neuroradiologists.CONCLUSION: The level of resident training had a significant effect on their diagnostic performance, and there was a good interobserver reliability between the results of residents and attending neuroradiologist.

SE 09 NR-04Variations in the origin and course of the extracranial vertebral artery on dual energy CT angiographyChia-Ying Lin, Ming-Tsung Chuang National Cheng Kung University Hospital, Taiwan. u8501122@gmail.com

PURPOSE: To investigate the prevalence of anatomical variations in the origin of vertebral arteries, and anomalous course of the extracranial vertebral artery using dual energy CT angiography.MATERIALS AND METHODS: We retrospectively reviewed head and neck DECT angiographies of 1218 consecutive patients during 2010-2014. The images were evaluated with special attention to the origin of VA and its level of entrance into and exit out of the transverse foramen of cervical spine, specific variations of VA including fenestration and intradural course of C1-C2 VA. RESULTS: The majority of left VA (1172/1218, 96.2%) originated from the left subclavian artery. Most of them (1158/1218, 95.1%) entered the transverse foramen at C6 level. Forty-four left VA (3.6%) originated from the aortic arch and thirty-six of them entered the transverse foramen at C5 level (3%). There was significant higher rate of VA entering the C5 transverse foramen when from aortic arch (Fisher exact test, p < 0.001). The majority of right VA (1209/1218, 99.3%) originated from the right subclavian artery, eight of them (0.7 %) from the aberrant right subclavian artery. One rare case of right VA (0.1%) from right common carotid artery entered the transverse foramen at C4 level. Five cases have atlanto-axial fenestration of the vertebral arteries and five cases have intradural course of left C1-C2 vertebral arteries. CONCLUSION: The study showed frequently found anatomical variations of vertebral artery in its origin and extracranial course. Appreciation of these variations is important to radiologist and surgeon in patient care.

Scientific Exhibitions 569

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SE 09 NR-05Longitudinal gray matter changes in cynomolgus monkeys administered with 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridineSoo Mee Lim1, Na-Young Shin1, Hyen Seok Jeong2 1Ewha Womans University Mokdong Hospital, 2Catholic Kwandong University International St. Mary's Hospital, Korea. soomee@ewha.ac.kr

PURPOSE: To investigate longitudinal changes in brain structure and motor symptoms after administration of 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP) in cynomolgus monkeys, which is a primate model of Parkinson's disease (PD).MATERIALS AND METHODS: 40 time-series brain MRI were acquired from six cynomolgus monkeys over 32 weeks and repeated motor symptom assessments over 15 months before and after the MPTP intramuscular administration using voxel = based morphometry. A mixed regression model was used to examine the relationship between the GM volume changes and motor symptom changes.RESULTS: The GM volumes of the frontostriatal area increased after the MPTP injection and gradually returned to its initial levels by 32 weeks, whereas those of the insula, superior/middle temporal gyrus, and cerebellum steadily declined after the administration (p < 0.05, multiple comparison-corrected). In the group analysis, subjects (n = 3) with the larger maximum increase of the GM volume in the frontostriatal regions showed worse prognosis of the motor symptom severity over 15 months than those with the smaller maximum increase (p for interaction = 0.019).CONCLUSION: Our in vivo analysis demonstrated the long-term impact of MPTP on brain structures, behaviors, and associations between them in a primate model of PD. The transient nature of the GM volume increase in the frontostriatal area and the predictive value of the maximum GM volume increase for motor symptom severity may suggest the importance of inflammatory responses in the pathophysiology of PD.

SE 09 NR-06Meningiomas: atypical features and its rare mimicsAi Peng Tan National University Health System, Singapore. tan_ai_peng@hotmail.com

Meningiomas represent approximately one third of incidental intracranial neoplasms and account for about 36% of all primary brain tumors. When typical neuroimaging characteristics such as homogenous avid

enhancement, isointense to mildly hyperintense on T2-weighted imaging, intralesional calcifications, overlying cranial hyperostosis, smooth interface with underlying brain parenchyma, enhancing dural tail and absence/minimal vasogenic edema are present, the diagnosis can often be easily made. However, this may not be the case at all times as a significant number of meningiomas (up to 10%) demonstrate atypical features such as the presence of cystic component, heterogeneous enhancement, marked perilesional edema, lack of dural attachment, nodular interface with underlying brain parenchyma and destruction of overlying cranial vault. This is further complicated by the presence of a wide variety of neoplastic and infective/inflammatory lesions that arise from the dura. We would like to illustrate the atypical features of meningioma as well as some of its rare mimics such as lymphoma, hemangiopericytoma, dural metastasis, tuberculoma and Langerhans cell histiocytosis (LCH).

SE 09 NR-07 Normal structures mimicking fracture on facial 3D CTJoo hee Lim, Kyoung Eun Lee, Ghi Jai Lee, Jae-Chan Shim Inje University Seoul Paik Hospital, Korea. arisia98@hanmail.net

Intrinsic fissures1. Tympanosquamous fissure2. Petrotympanic fissure3. Petrosquamous fissure4. Tympanomastoid sutureExtrinsic fissures1. Occipitomastoid suture2. Petrooccipital suture3. Sphenosquamosal suture4. Sphenopetrosal sutureIntrinsic channels1. Petromastoid canal2. Hiatus of the facial canal3. Singular canal4. Vestibular aqueduct5. Cochlear aqueduct6. Inferior tympanic canaliculus7. Mastoid canaliculusNormal variations1. Persistent metopic suture2. Persistent sphenooccipital synchondrosis3. Prominent diploic venous channelsReviewing of normal structures that we can ignore and normal variations seen as pseudofractures on facial CT can be helpful in accurate diagnosis of fractures in trauma patients.

570 KCR 2016

Neuroradiology

SE 09 NR-08 CEST MRI to map γ-aminobutyric acid, glutamate, myoinositol, glycine, and asparagine: phantom experimentsJi Soo Kim1, Jang-Hoo Oh1, Hyug-Gi Kim1, Ha-Kyu Jeong2, Dong-Cheol Woo3, Geon-Ho Jahng1, Soo Youl Lee4 1Kyung Hee University Hospital at Gangdong, 2Philips Healthcare Korea, 3Asan Medical Center, 4Department of Biomedical Engineering, Korea. ghjahng@gmail.com

BACKGROUND: Currently, most of CEST MRI studies were investigated to map amide protons in tumor or stroke patients and to do amine protons in stroke patients with a high magnetic field. In this study, we want to investigate CEST MRI to map several amino acids composed of amyloid beta (Ab) proteins which are existed in the Alzheimer's disease (AD) AD brain.PURPOSE: The object ive of this study was to investigate the physical and technical development of chemical exchange saturation transfer (CEST) MRI using a clinical 3T MRI to map asparagine (Asn), γ-aminobutyric acid (GABA), glutamate (Glu), glycine (Gly), and myoinositol (MI) which exist in the brain tissue.MATERIALS AND METHODS: Phantoms with nine different conditions at concentrations of 10, 30, and 50 mM and pH values of 5.6, 6.2, and 7.4 were prepared for the five target molecules to evaluate CEST effect for concentration, pH, and B1 amplitude. CEST images at the offset frequency range of ± 6 parts per million (ppm) were acquired using a pulsed RF saturation scheme with a 3T clinical MRI. Voxel-based B0 inhomogeneity correction was performed by fitting the full Z-spectrum to estimate the center frequency using the spline interpolation method. Voxel-based CEST asymmetry map was calculated to evaluate amide (-NH), amine (-NH2), and hydroxyl (-OH) groups for the five target molecules.RESULTS: At 3T MRI, the CEST effect of Glu, GABA, and Gly was clearly increased with increasing concentrations. The CEST effect of MI was not very large with any noticeable differences at different concentrations. The CEST effect of Glu and Gly was increased with increasing acidity. The highest CEST asymmetry for GABA was observed at pH 6.2. The CEST effect of Glu, GABA, and Gly was increased with increasing B1 amplitude. The CEST effect at 3T was seen for Glu, GABA, Gly and MI, but not for Asn, with the peaks of Glu = 2.7 ppm, GABA = 2.7 ppm, Gly = 2.7 ppm, and MI = 0.9 ppm.CONCLUSION: For all target molecules, the CEST effect at the 3T human MRI was increased with increasing concentration and B1 amplitude, but varied

with different pH value, depending on the characteristics of the molecules. The CEST effect of Asn was not observed at the 3T MRI system. The CEST effect of MI may be not suitable with the clinical MRI system. These results show the possibility of CEST imaging with the amine protons using 3T MRI in the brain of several neuronal diseases.

SE 09 NR-09 Genetic variances of IDE contributed to altered brain structure and function in subjects with mild cognitive impairmentJia Huang Zhongda Hospital Affiliated to Southeast University, China. 754772765@qq.com

PURPOSE: The dysfunctions of insulin degrading enzyme (IDE) represent key mechanism underlying the insulin resistance associated with Alzheimer's disease (AD). Exploring the roles of genetic variations of IED in brain structure and function will help to improve our understanding of AD pathophysiology.MATERIALS AND METHODS: 43 subjects with mild cognitive impairment (MCI) and 30 matched healthy controls were employed, and they all had evaluations cognitive function, structure and functional magnetic resonance imaging (MRI) scans. Whole exome sequencing of IDE gene was also performed and total of 11 common single nucleotide polymorphisms (SNPs) after quality control were enrolled in further analysis. Genetic association analyses were applied to explore the influences of IDE SNPs on AD-related MRI phenotypes.RESULTS: For brain structure, MCI-by-genotype revealed interactions of both rs1887922 (β = -0.58, FDR-corrected p = 0.035) and rs4646954 (β = -0.35, FDR-corrected p = 0.019) and thickness of entorhinal cortex. Furthermore, rs1887922 also associated with atrophy of parahippocampal (β = -0.54, FDR-corrected p = 0.02). Subsequent haplotype-based analysis further supported the association for the three mentioned SNPs and atrophy of entorhinal cortex (p < 0.001). In the analyses for neural activity, rs1832196 and rs1999764 showed negative connections with the activity in the right posterior cingulated (RPCC) (β = -0.36 and -0.47, FDR-corrected p = 0.016 and 0.038 respectively). Moreover, for the MCI subjects, the more the atrophy of parahippocampal, the more worse the general cognition (rho = 0.38, p = 0.01) and memory (rho = 0.47, p = 0.002). The similar association was also detected between RPCC activity and memory (rho = 0.41, p = 0.005).CONCLUSION: IDE play a role of in AD pathology partially by deteriorating the brain atrophy and activity,

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which may represent a clinical biomarker to predict the AD process.

SE 09 NR-10 Studying the CT features of oligodendrogliomaOyuntogos Batdelger1, Badamsed Tserendorj2 1Mongolian National University of Medical Science, 2Third Central Hospital of Mongolia, Mongolia. b.togosoo1@yahoo.com

PURPOSE: To study and determine computer tomographic features of oligodendroglioma and to develop diagnostic criteria of computer tomography for oligodendroglioma.МATERIALS AND METHODS: We developed study chart for the computer tomographic findings of the 11 patients (benign oligodendroglioma 6, malignant oligodendrolglioma 5), who are diagnosed with oligodendroglial tumor at computer tomography section of Department of Radiology of Third Central Hospital named after P.N. Shastin, Mongolia between years of 2015 to 2016. The diagnosis is confirmed by surgery and biopsy.RESULTS: The 60% of malignant oligodendrolglioma was located in fronto-parietal region and lateral ventricle was uniformly dilated, in 80% lesion was non homogenous, had poorly demarcated and irregularly shaped margins and presence of midline shift was noted. In 100% tumor density was heterogeneously enhanced, after contrast injection the density of the lesion was heterogeneously enhanced and brain edema was noted. Benign oligodendroglioma was located in parieto-occipital region, lesion was non homogenous, well demarcated and had hetero and homogenously enhanced density. After contrast injection it revealed, that heterogeneous and homogenous enhancement of lesion’s density, brain edema, midline shift, uniform and

non-uniform dilation of left ventricle. The presence of all above mentioned computer tomographic features were statistically significant (p < 0.05). Based on our study we found that, evaluation of location of lesion, homogeneity, density, changing of lesion’s density after contrast injection, brain edema, midline and lateral ventricles were main computer tomographic diagnostic criteria for benign and malignant oligodendroglioma.CONCLUSION: 1. We determined computer tomographic features of benign and malignant oligodendroglioma. 2. We developed computer tomographic diagnostic and differential diagnostic criteria for benign and malignant oligodendroglioma.

SE 09 NR-11Assessment of collateral status with multiphase dynamic contrast-enhanced MR imagingSanghyeon Kim, Myongjin Kang, Subseob Choi Dong-A University Hospital, Korea. g4439@naver.com

PURPOSE: Collateral status is an important determinant of clinical outcome in patients with acute ischemic stroke. The purpose of this study was to evaluate whether collateral status can be demonstrated using dynamic contrast-enhanced MR imaging (DCE MRI).MATERIALS AND METHODS: MRI was performed using 3.0T (GE Medical Systems, Milwaukee, WI, USA) in patients with acute ischemic stroke and moyamoya disease. DCE MRI was performed by using a T1-WI 3D FSPGR sequence, following the injection of contrast agent. Three images of peak arterial, peak venous and late venous phases were selected using a contrast concentration-time curve. Pial arterial filling in the lesion was evaluated during multiphase by comparing it to similar arteries in the unaffected hemisphere. We compared this imaging technique with digital subtraction angiography (DSA) or dynamic susceptibility contrast (DSC) perfusion MRI.RESULT: There was good correlation between DCE MRI-based and DSA-based or DSC perfusion MRI-based collateral status.CONCLUSION: DCE MRI maybe a useful imaging technique for evaluating collaterals.

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Neuroradiology

SE 09 NR-12Benign intracranial tumor showing perineural invasion: atypical meningioma Ali Kemal Sivrioglu1, Hakan Mutlu2 1Kasımpasa Military Hospital, 2GATA Haydarpasa Teaching Hospital, Turkey.draksivrioglu@gmail.com.tr

Perineural spread is common in head and neck malignancies; especially seen in adenoid cystic carcinoma. It can also be seen in squamous cell carcinoma, malignant melanoma, lymphoma, basal cell carcinoma, adenocarcinoma, mucoepidermoid tumor, rhabdomyosarcoma, chondrosarcoma, malignant mixed tumor, and esthesioneuroblastoma. Perineural spread is usually associated with cavernous sinus, cranial nerve infiltration, skull base invasion, and has bad prognosis. Most CS meningiomas arise from the lateral dural wall, but sometimes they may be exclusively inside the CS. Meningiomas may extend inside the CS and the Meckel cave and via the porous trigeminus into the prepontine cistern. They may have an appearance very similar to schwannomas. In this article, We presented a 52-year-old woman with atypical meningioma localized in right cavernous sinus and middle cranial fossa, extending down into the infratemporal fossa through the foramen ovale.

SE 09 NR-13 Free ventricular shunt catheter in right lateral ventricleAli Kemal Sivrioglu, Goksel Guven Kasımpasa Military Hospital, Turkey. draksivrioglu@gmail.com.tr

CASE REPORT: A 19-year-old male patient which has a history of ventriculoperitoneal shunt operation which was done four years ago, was evaluated in the ER because of sudden onset severe headache. This shunting operation was done for idiopathic hydrocephalus. After 2 years from the operation, the patient had a severe headache and it was found that the vetriculoperitoneal shunt was disconnected and the cranial part had been floating in the right ventricle. After the evaluation re-shunting had been done and proximal part of the shunt was left in the ventricle. We evaluated the patient, there was no significant finding in physical examination. The cranial CT showed the two intracranial catheters, one freely floating in the temporal horn through the atrium of the right lateral ventricle, and the one in the right lateral ventricle with extracranial continuity. Also there was no sign of ventricular dilatation that may be treated as hydrocephaly. A CSF sampling was performed because

of subfebrile fever and meningitis and ventriculitis were both excluded. The patient was treated symptomatic. The routine follow-up program was established.DISCUSSION: VP shunt appl icat ions are the most commonly used methods in the treatment of hydrocephaly. The migrations of the elements of VP shunt system toward the cranium are one of the complications that are rarely seen. The disconnection of the ventricular catheter from the shunt valve and its migration toward the cranium can be explained due surgical inattention and the negative intracranial pressure suction effect.

SE 09 NR-14Meningioma - in and outAruna Patil, Sharath Kumar, Shrivalli Nandikoor Apollo Hospitals, India. dr.arunarpatil@gmail.com

TEACHING POINTS: Meningiomas are the most common nonglial tumors of the central nervous system.- Review the types of intracranial, spinal and extracranial

meningiomas, their typical and atypical imaging features

- Associations, complications and imaging mimics of meningioma

- Role of advanced imaging techniques in meningioma TABLE OF CONTENTS: - Meningiomas based on location: cranial (cerebral

convexity, olfactory lobe, parafalcine, falcotentorial, planum sphenoidale, sellar, tentorial, orbital, cerebello-pontine angle, intraventricular), extracranial (intradiploic, parapharyngeal, temporal) and spinal.

- Associations and complications: bony changes, perilesional edema, mass effect and syndromic associations neurofibromatosis 2, gardeners.

- Atypical meningiomas: cystic meningioma, lipoblastic meningioma, hemangiopericytoma, meningiomatosis

- Mimics: chloroma, sarcoidosis, metastases, lymphoma, schwannoma, rosai dorfman disease, plasmacytoma etc.

- Advanced imaging: role of novel MR sequences, diffusion weighted imaging, perfusion imaging, MR spectroscopy, diffusion tensor imaging and conventional angiography in imaging of meningioma.

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SE 09 NR-15Microhemorrhages in the corpus callosum as the distinctive anoxic brain injuryDong Woo Park, Tae Yoon Kim Hanyang University Guri Hospital, Korea. dwpark@hanyang.ac.kr

PURPOSE: Vasogenic edema in the corpus callosum is reported to be a characteristic finding in severe acute respiratory distress including high-altitude cerebral edema (HACE). Furthermore, microhemorrhages in the corpus callosum have been found at autopsies in HACE victims. This study is to present microhemorrhages in the corpus callosum in brain MR images after suffering from anoxic brain injury.MATERIALS AND METHODS: Among 16 patients who survived from anoxic brain injury and conducted MR imaging, susceptibility weighted image (SWI) of five patients who show microhemorrhages in the corpus callosum are evaluated.RESULTS: SWI reveals multiple microhemorrhages, predominantly in the corpus callosum in all five patients who suffered from anoxic brain injury. An identical pattern of microhemorrhages has previously been described in climbers who suffered from high altitude cerebral edema (HACE). The incidence of microhemorrhage to be detected on SWI is about 31%.CONCLUSION: This study implies that anoxic brain injury show congruent cerebral injuries as high-altitude cerebral edema. Microhemorrhages in the corpus callosum could be suggestive MR findings that characterized as anoxic brain injury. It may be developed by disruption of the blood-brain barrier due to increased capillary and central venous pressures from ‘anoxic brain injury’ induced hypoxia.

SE 09 NR-1618F-FDG PET CT in the diagnosis of neurodegenerative diseases: a pictorial reviewWanying Xie1, Andrew Eik Hock Tan2, Winnie Wing Chuen Lam1, Kelvin Siu Hoong Loke1, David Chee Eng Ng1 1Singapore General Hospital, 2Raffles Medical Group, Singapore. xie.wanying@sgh.com.sg

The current approach in diagnosis of dementia relies on clinical judgment based on cognitive function, laboratory tests and other diagnostic tools such as structural neuroimaging. Clinical judgment can be subjective and structural neuroimaging such as CT and MRI may not reveal morphological change in early stages of the disease. Of interest is the use of 18F-fluoro-deoxyglucose

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positron emission tomography (18F-FDG PET) CT, which is a sensitive diagnostic tool with high negative predictive value. In addition, 18F-FDG PET CT can be used to distinguish different types of neurodegenerative diseases based on their unique pattern of regional cerebral metabolic uptake.This is a pictorial review of the spectrum of neurodege-nerative diseases that cause dementia on 18F-FDG PET CT. The examples presented include Alzheimer's disease, as well as other less common causes such as frontotemporal disease and its variants, dementia with Lewy bodies, Parkinson's related dementia, posterior cortical atrophy and fatal familial insomnia. Semi-quantitative analysis of the metabolic activity in the individual regions of the brain was performed with global cerebral metabolic activity as reference. The images were cross referenced with a database of control subjects in the same age group with computer aided automated analysis to account for age related changes in cerebral metabolic activity. The images are then presented as 3D stereotactic surface projection maps. At the end of the review, the reader should be able to 1) identify abnormal areas of hypometabolism in 18F-FDG PET CT brain 2) develop a systematic approach to read 18F-FDG PET CT brain studies and 3) recognize the pattern of regional cerebral metabolic differences pertaining to each neurodegenerative condition.

SE 09 NR-17ASL MR imaging: research and clinical applications and diagnostic pitfallsDae Seob Choi, Ju Ho Kim Gyeongsang National University Hospital, Korea. choids@gnu.ac.kr

ASL MR imaging is a powerful tool to obtain the status of tissue perfusion in the healthy and impaired brain without additional administration of contrast media. With recent advances of hard and soft ware techniques, we can have used the technique with a commercial scanner. For clinical practice, it can be used in various cerebral diseases such as stroke, tumor, infection, seizure and degenerative and demyelinating diseases.In the research for the healthy and diseased brain, we can also applicate the technique as a tool of functional magnetic imaging (fMRI). With the contrast differences of regional cerebral perfusion between resting and task-performing states, it can be used as a technique for the task-based fMRI study. According to some leading investigators, it can also be used for the resting state fMRI (rs-fMRI).The purpose of this presentation is to introduce ASL fMRI techniques (both of task-based and rs-fMRI), to demonstrate our clinical cases during recent periods,

and to discuss the benefit and pitfalls of ASL perfusion imaging.

SE 09 NR-18Common and uncommon imaging features of central nervous system lymphoma on traditional and advanced imagingJung eun Lee, Eun Ja Lee, Eun Kyoung Lee Dongguk University Ilsan Hospital, Korea. ejl1048@hanmail.net

PURPOSE: Although central nervous system (CNS) lymphomas demonstrate some of characteristic magnetic resonance imaging (MRI) findings, their MR imaging features can vary with immune status, histological type and location and often overlap with other intracranial tumors making definitive diagnosis challenging. In this educational exhibit, we depict common and uncommon imaging features of central nervous system (CNS) lymphoma on traditional and advanced imaging.CONTENTS: Lymphoma of the CNS consists of 2 major subtypes: secondary CNS involvement by systemic lymphoma and primary CNS lymphoma (PCNSL). Approximately two-thirds of secondary CNS lymphoma present with leptomeningeal spread and one-third, with parenchymal disease. Neuroimaging findings suggestive of leptomeningeal metastases include leptomeningeal, subependymal, dural, or cranial nerve enhancement. PCNSL often has a characteristic appearance on both CT and MR imaging due to its hypercellularity, high nuclear/cytoplasmic ratio, disruption of the blood-brain barrier, and its predilection for the periventricular and superficial regions. Typical MR imaging features of PCNSL in immunocompetent patients are characterized by their periventricular locations, well-defined margin, moderate or marked edema, and intense and homogeneous nodular enhancement. Lack of enhancement or heterogeneous enhancement, hemorrhage, necrosis and calcifications are unusual imaging features in immunocompetent patients. Internal hemorrhage and necrosis present in immunocompromised individuals. Immunocompromised patients with PCNSL are often diagnosed with multifocal lesions with irregular or peripheral, and ring-like enhancement. Primary dural lymphoma is a rare subtype of PCNSL which presents as a single or multiple extraaxial masses like meningioma. Advanced imaging techniques such as diffusion weighted imaging, perfusion MR imaging, MR spectroscopy and susceptibility weighted imaging may help to differentiate CNS lymphomas from other lesions of the brain.CONCLUSION: CNS lymphoma is a chemosensitive and radiosensitive tumor and an early diagnosis

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may shift the treatment from extensive surgery to radiotherapy. The accurate diagnosis of CNS lymphoma is crucial for proper management and prognosis. These imaging features may allow earlier recognition of CNS lymphoma and facilitate optimal treatment.

SE 09 NR-19 Imaging of neurologic conditions during pregnancy and the postpartum periodYeon Su An1, Seul Kee Kim2, Woong Yoon1, Byung Hyun Baek1, Yun Young Lee2 1Chonnam National University Hospital, 2Chonnam National University Hwasun Hospital, Korea. kimsk.rad@gmail.com

PURPOSE: To review imaging findings of neurologic disorders associated with pregnancy and the postpartum period.CONTENTS: Acute neurological disorders are relatively rare in young women of childbearing age. However, during pregnancy and the postpartum period, several diseases increase in prevalence. A variety of physiologic, immunologic, and hemodynamic changes occur throughout pregnancy. These changes that occur during pregnancy and the puerperium can adversely affect the central nervous system and pituitary gland. Several disorders have direct association with reproductive process; eclamptic encephalopathy, cerebral angiopathy, Sheehan syndrome, lymphocytic hypophysit is. Others, such as cerebral venous thrombosis, ischemic stroke, dural venous thrombosis, and intracerebral hemorrhage, are indirectly related to pregnancy, but increase in frequency in pregnant women. Many of these neurological diseases can lead to devastating complications if not recognized early. As neurological diseases contribute to approximately 20% of maternal deaths, it is critical that radiologist identify these at-risk patients. In this educational exhibition, we will review pathophysiology and imaging findings of neurologic diseases associated with pregnancy.CONCLUSION: Neurological d isorders dur ing pregnancy could have serious complications for both mother and fetus. Radiologists should be familiar with these entities to reach a prompt diagnosis and initiate rapid and efficient treatment.

SE 09 NR-20High-resolution MRI vessel wall imaging: changes in atherosclerosis in follow-up periodYoung Jin Heo, Jin Wook Baek, Hae Woong Jeong Inje University Busan Paik Hospital, Korea. youngjin726@hanmail.net

PURPOSE: High resolution magnetic resonance imaging (HR-MRI) has been widely used in the evaluation of intracranial artery walls. It has an advantage in define vessel wall characteristics of intracranial artery disease. Vulnerable composition, inflammation and neovascularization are considered risk factors for developing ischemic stroke. Recent study suggests that atorvastatin therapy reduced the inflammatory response and stabilize vulnerable plaque. Thus, we investigated changes of vessel wall in atherosclerosis patients with MCA stenosis and compared with moyamoya patients.MATERIALS AND METHODS: From October 2012 to April 2015, we prospectively performed initial and follow-up HRMRI for the patients with stenosis involving middle cerebral artery. The HR-MRI protocol included 3D proton density, oblique sagittal proton density, T1, contrast enhanced T1 weighted black blood MRI, time-of-flight MRA of the circle of Willis. Follow-up HR-MRI was performed after atorvastatin therapy. Vessel wall characteristics including wall enhancement, wall thickening, and luminal narrowing were evaluated.RESULTS: Twenty-five patients with atherosclerosis and 6 patients with moyamoya disease were included. In atherosclerosis group, 7 patients showed decreased extent of plaque and 8 patients showed decreased contrast enhancement of vessel wall. In the moyamoya disease group, 4 patients showed no significant interval change of wall thickening and 6 patients showed no significant interval change of vessel wall enhancement.CONCLUSION: Post-gadolinium intracranial HR-MRI appears to be a useful tool in the evaluation of vessel wall morphologic changes associated plaque vulnerability in atherosclerosis patients after atorvastatin therapy.

SE 09 NR-21 Added value of high-resolution vessel wall MR imaging of intracranial vertebral artery dissection in planning of the endovascular treatmentYoung Jin Heo, Dong Gun Kim, Jin Wook Baek, Hae Woong Jeong Inje University Busan Paik Hospital, Korea. youngjin726@hanmail.net

PURPOSE: Conventional angiography is traditionally considered the gold standard for diagnosis, but optimal

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imaging method is still debated. High-resolution MR imaging (HR-MRI) is a non-invasive imaging technique to evaluate the lumen and wall of affected arteries. Thus, the purpose of our study was to evaluate added value of high-resolution MRI of intracranial artery dissecting aneurysm in planning of the endovascular treatment.MATERIALS AND METHODS: We retrospectively reviewed patients who performed both HR-MRI and conventional angiography before endovascular treatment from August 2013 to April 2016. Two radiologists evaluated primary and secondary features of intracranial arterial dissection in conventional angiography and HR-MRI.RESULTS: Twelve patients with 13 intracranial vertebral artery dissections were included. Hidden pseudolumen was seen in 8 patients on HR-MRI. HR-MRIs also provided additional information of hidden structures such as intimal flap (n = 8), inlet of the false lumen (n = 8), size of the intramural hematoma (n = 9). In addition, HR-MRIs were provided accurate ostium of small branching vessel in 2 cases.CONCLUSION: HR-MRI has an additional value to the conventional angiography in the evaluation of the dissection in the arterial wall when planning the endovascular treatment.

SE 09 NR-22 Correlation of clinical syndromes with cortical branch anatomy in acute ischemic strokeYun Young Lee1, Woong Yoon2, Seul Kee Kim1, Byung Hyun Baek2 1Chonnam National University Hwasun Hospital, 2Chonnam National University Hospital, Korea. radyoon@jnu.ac.kr

PURPOSE: 1. To review the functional anatomy of the cerebral

hemispheres and their associated blood supply.2. To review the symptoms and signs induced by

specific infarcted area using case-based approach.3. To infer possible location of involved territory and

vessels in acute ischemic stroke from clinical informations.

CONTENT ORGANIZATION: 1. Main functional areas of cerebral cortex2. Vascular territories of the three main cerebral arteries3. Case-based review of clinical syndromes of the three

main cerebral arterial infarction- MCA territory (conjugate eye deviation, aphasia,

hemineglect, cortical sensory loss, visual field defect, Gerstmann's syndrome)

- ACA territory (Hypobulia, apathy, indifference, grasp reflex)

- PCA territory (Contralateral homonymous hemianopia,

alexia without agraphia)CONCLUSION: Understanding the functional anatomy of the cerebrum and recognizing the classic syndromes induced by infarctions of MCA, ACA, and PCA territories play an important role in evaluating patients with acute ischemic stroke.

SE 09 NR-23 Trigeminal neuropathy: from normal anatomy, clinical manifestation to pathological conditionsMing-Tsung Chuang, Hui-Ming Wang, Chia-Ying Lin National Cheng-Kung University Hospital, Taiwan. u8501122@gmail.com

PURPOSE: 1. To review the normal anatomy of trigeminal nerve. 2. To describe the clinical manifestations of trigeminal

nerve palsy. 3. To demonstrate the various pathological conditions

affecting trigeminal nerve based on anatomic location. 4. To demonstrate the different stages of trigeminal

nerve denervation. CONTENT ORGANIZATION: 1. Anatomy of trigeminal nerve: brainstem nuclei,

cisternal segment, Meckel cave, gasserian ganglion, and trifurcation.

2. Demonstrate clinical manifestation. 3. Pathological conditions based on location:

1) brainstem: MS, infarct, cavernoma 2) cistern: neurovascular compression, lymphoma,

meningioma, epidermiod cyst, cryptoccocal neuritis 3) Meckel cave/cavernous sinus: neuroma, meningioma,

metastasis 4) extracranial region: schwannoma, perineural

spreading, subacute infarct 4. Different stage of denervation. SUMMARY: 1. Understanding normal anatomy of trigeminal nerve is

important in interpretation. 2. Familiarity with various pathological conditions

enables us to a prompt management for the patients, especially for those with trigeminal denervation but unknown origin.

3. Learning the pathway of perineural spreading. 4. Understanding the different stages of denervation.

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SE 09 NR-24Application of post-contrast FLAIR imaging in differentiation between glioblastoma and solitary brain metastasisInseon Ryoo, Sangil Suh, Arim Park, Hae Young Seol Korea University Guro Hospital, Korea. sangil.suh@gmail.com

PURPOSE: To evaluate the usefulness of post-contrast FLAIR image compared to conventional post-contrast T1-weighted image (T1WI) in differentiation between glioblastoma and solitary brain metastasis.MATERIALS AND METHODS: This study included 31 patients with pathologically confirmed glioblastoma multiforme (n = 19) or solitary brain metastasis (n = 12), who underwent preoperative MR imaging including pre and post-contrast T1WI and pre and post-contrast FLAIR images. The maximum diameters of enhancing lesions were measured on both post-contrast T1WI and FLAIR. The ratios of the maximum diameter of the enhancing lesion on post-contrast FLAIR (DF) to that of post-contrast T1WI (DT1), the maximum diameter of peritumoral FLAIR high signal lesion on pre-contrast FLAIR image (Dedema) to DT1, and Dedema to DF were calculated and compared between the two diseases. Correlation between DF/DT1 and Dedema/DT1 was also evaluated.RESULTS: The DF/DT1 of solitary brain metastasis (1.07 ± 0.06) is significantly larger than that of glioblastoma (1.01 ± 0.02) (p = 0.005). The Dedema/DT1 of solitary metastasis (2.37 ± 1.32) was also larger than Dedema/DT1 of glioblastoma (1.53 ± 0.36) (p = 0.05). The DF/DT1

and Dedema/DT1 showed positive correlation (r = 0.7; 95% confidence interval, 0.46-0.85; p < 0.001).CONCLUSION: Unlike many advanced MR imaging methods including perfusion weighted imaging, diffusion tensor imaging, and spectroscopy which have been studied a lot, post-contrast FLAIR images can be obtained without significant increase in examination time or post processing steps. Post-contrast FLAIR images can be helpful in daily practices in differentiation between glioblastoma multiforme and solitary brain metastasis that have been difficult to differentiate from each other by conventional brain MR imaging.

SE 09 NR-25 Aneurysmal location and leukoaraiosis distribution in screening patients as detected at 1.5T MRI: UB Songdo Hospital reviewNergui Bayanzul1, Orkhon Gombosuren1, Fransk Eduardo Sanchez Carpio1, Ganbat Sonomtseren2, Sarangerel Ulziikhutag1, Tuvshinjargal Dashjamts3 1UB Songdo Hospital, 2Seoul Seniors Hospital, 3Mongolian National University of Medical Sciences, Mongolia. nergui_72@yahoo.com

PURPOSE: Introduction of MRI in Mongolia allowed noninvasive assessment of intracranial vessels without ionizing radiation. The distribution of both aneurysms and leukoaraiosis may be influenced by anatomic variations of the circle of Willis. In Mongolia, we did not national data on aneurysm location and leukoaraiosis distribution. We aimed to investigate the location of aneurysms, estimate leukoaraiosis in patients with aneurysms, and their correlation.MATERIALS AND METHODS: We retrospectively revised MRI and MR angiography performed at the Ulaanbaatar Songdo Hospital in January to December 2015. MRI exams were performed at 8-channel 1.5T Siemens Symphony (the Netherlands).RESULTS: From 2648 brain MRI examinations, we detected 81 patients with aneurysms aged 0-79 years. From 81, 36.7% was aged 30-49. F:M = 51:15. Multiple aneurysms were seen in 12/81 (14.5%), from them 9 were female. Aneurysms were located at ICA cavernous portion in 36/81 (44.4%), at MCA in 21/81 (25.9%), at AComA 10/81 (12.3%), at PCA and PComA 1/81 (1.2%) retrospectively. The maximum dimension of detected aneurysm ranged 2-28 mm; it was less than 2 mm in 4/81 (4.9%), 2-7 mm in 65/81 (80.2%), and over 13 mm in 2/81 (2.5%). Hypoplasia was noted in 20/81 (24.7%) of all aneurysm patients. In study subjects, 34/81 (47.2%) revealed non-specific T2-hyperintensities in cerebral white matter or leukoaraiosis/UBOs; from them less than 2 foci were detected in 7/34 (5.9%), 2-4 foci in 9/81 (26.5%), more than 4 foci in 18/34 (52.9%). Distribution of UBOs was symmetric in 22/34 (64.7%) and asymmetric in 12/34 (35.3%).CONCLUSION: The most common site for aneurysms was ICA cavernous portions. Leukoaraiosis was relatively common in aneurysm patients in all age group. Relatively high prevalence of leukoaraiosis in aneurysm patients may associate with increased stroke risk compared to non-aneurysm patients.

578 KCR 2016

Neuroradiology

SE 09 NR-26Diagnostic value of susceptibility- weighted images in cerebral venous thrombosisHwa Seon Shin, Dae Seob Choi Gyeongsang National University Hospital, Korea. choids@gnu.ac.kr

PURPOSE: Susceptibility vessel sign on susceptibility-weighted imaging (SWI) has a high sensitivity and specificity to detect the intra-arterial thrombus. However, Little is known concerning the diagnostic value of SWI in cerebral venous thrombosis (CVT).MATERIALS AND METHODS: We performed a retrospective analysis of 18 patients with CVT between February 2012 and March 2016. According to the thrombus location, the sensitivity of SWI was tested.RESULTS: In 18 patients, we found a total of 44 thrombi. The sensitivity of SWI to detect thrombus in the superior sagittal sinus (SSS), transverse sinus (TS), sigmoid sinus (SS), straight sinus (StS) and cortical vein were estimated 35.7%, 50%, 66.7%, 50% and 100%.CONCLUSION: SWI is useful examination to detect cortical venous thrombus, but there is a limit to detect thrombus in the other sinus or venous system.

SE 09 NR-27 Unusual ruptured intracranial aneurysms: with interventional treatmentSung hoon Oh, In Kyu Yu Eulji University Hospital, Korea. ohsh4803@naver.com

PURPOSE:1. To know the location and incidence of unusual located

intracranial aneurysms.2. To understand the specific clinical symptoms, imaging

features, and interventional treatment tools of each unusual intracranial aneurysms.

CONTENT ORGANIZATION: Each of unusual intracranial aneurysm’s specific symptoms, CT and MR angiography images, with interventional angiographic images are included Unusual intracranial aneurysms classified by following three aneurysmal types.1. Perforator aneurysm

1) A1 aneurysm2) M1 aneurysm3) P1, P2 aneurysm

2. Uncommon bifurcated aneurysm1) Dorsal wall aneurysm of the distal internal carotid

artery2) Basilar artery trunk aneurysm in segmental BA

fenestration3. (Dissecting) pseudoaneurysm

1) M4 cortical aneurysm2) V4 dissecting pseudoaneurysm3) PICA - P3 aneurysm

TEACHING POINTS: To know the location and incidence of each of unusual intracranial aneurysms. To easily detect unusual intracranial aneurysms by using the information of specific clinical symptoms and imaging features. To receive early, appropriate treatment for prevention of irreversible severe complications, such as cerebral hemorrhage by aneurysmal rupture.

SE 09 NR-28Various intracranial cystic or solid and cystic tumors: CT and MR imaging features with clinicopathologic correlationSung hoon Oh, In Kyu Yu Eulji University Hospital, Korea. ohsh4803@naver.com

PURPOSE:1. To know the various CT and MR imaging features,

clinical and pathologic features of intracranial cystic tumors.

2. To understand important imaging findings for differential diagnosis of intracranial cystic tumors from other cystic tumors.

CONTENT ORGANIZATION: CT and MR images (conventional MR, diffusion weighted image, perfusion MR and MR spectroscopy), clinical and pathologic features of each intracranial entire cystic and partial cystic tumors are included. Intracranial cystic tumors classified into solid and cystic tumor, dominantly cystic tumor, and entire cystic benign tumors.1. Solid and cystic tumor

1) Ganglioglioma2) Oligodendroglioma3) Supratentorial ependymoma4) Cystic schwannoma5) Medulloblastoma (PNET)

2. Dominantly cystic tumor1) Pilocytic astrocytoma2) Cystic hemangioblastoma3) Cystic ganglioglioma4) Pleomorphic xanthoastrocytoma (PXA)5) Cystic metastasis6) Cystic GBM

3. Entire benign cyst1) Neuroglial cyst2) Choroid plexus cyst3) Pineal cyst4) Arachnoid cyst5) Hippocampal fissure cyst

TEACHING POINTS: There are many different kinds of intracranial cystic tumors, and also they have various CT

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and MR imaging features. Among the various imaging features, knowing the tumor’s location and imaging clues for differential diagnosis will help to make an accurate diagnosis.

SE 09 NR-29 Intracystic hemorrhage and rupture of intracranial arachnoid cyst as an unusual cause of spontaneous subdural hemorrhage in a young adult: case reportCatherine Khi Ling Kong, Yu Hao Mah, Sii Ing Yun Hospital Sungai Buloh, Malaysia. khi_ling@yahoo.com

BACKGROUND: Arachnoid cyst is the commonest congenital intracranial cystic abnormality, commonly detected incidentally in asymptomatic patients.CASE REPORT: A 34-year-old healthy lady, presented with 2 months history of biparietal throbbing headache, associated with nausea, vomiting and blurring of vision. There was no history of head trauma. CT brain revealed right frontotemporal acute on chronic subdural hemorrhage (SDH) with mass effect and cerebral edema. CTA cerebral yielded negative finding. Burrhole surgery and drainage of SDH was conducted. Her postoperative recovery was uneventful. Follow-up CT brain at 2-months revealed a right temporal extraaxial cystic lesion. MRI confirmed the presence of right middle cranial fossa arachnoid cyst. Hence intracystic hemorrhage and rupture of a pre-existing arachnoid cyst was concluded as the cause of spontaneous SDH in this patient.CONCLUSION: Hemorrhage or rupture of an intracranial arachnoid cyst is a known but rare complication. The cyst might be masked during acute hemorrhage and the diagnosis could be challenging in the absence of previous imaging evidence.

SE 09 NR-30 Vertebral artery hypoplasia: is it cause or effect of vertebral artery dissection?Mina Park1, Na-Young Shin2, Seung-koo Lee3, Soo Mee Lim2 1Konkuk University Medical Center, 2Ewha Womans University Mokdong Hospital, 3Severance Hospital, Korea. nyshin@ewha.ac.kr

PURPOSE: To assess the true incidence of the vertebral artery hypoplasia (VAH) and the dynamic change of the vertebral artery diameter on the follow-up imaging in the spontaneous vertebral artery dissection (sVAD) patients.MATERIALS AND METHODS: In this retrospective study, the population comprised 92 patients with 99 sVAD between 2003 and 2014. VAH and sVAD were diagnosed by either conventional angiography, magnetic resonance imaging, or computed tomographic angiography and presence of VAH and primary lesion shape (aneurysmal dilatation without stenosis, pearl-and-string, and steno-occlusion without aneurysmal dilatation) of sVAD were evaluated. Furthermore, the radiologic evolution of sVAD and presence of VAH were also evaluated on follow-up imaging. The respective frequencies of the VAH and radiologic findings at initial and follow-up imaging studies were compared by Fisher’s exact test.RESULTS: VAH was detected in 22 (23.9%) subjects and there were 13 (14.1%) subjects with ipsilateral VAH and 9 (9.7%) with contralateral VAH to the sVAD site. Primary lesion shape showed statistically different frequency according to the presence of VAH (p = 0.020): steno-occlusion without dilatation was more frequently seen in the ipsilateral VAH group (46.2%), while dilatation without stenosis was more frequent in the contralateral VAH group (44.4%). Of total 83 sVAD lesions with available follow up imaging, diffuse VA narrowing with a diameter less than 2 mm (VAH-like

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Neuroradiology

appearance) was newly developed in 8 lesions (9.6%). Two (2.4%) sVAD lesions with VAH on initial MR imaging showed no evidence of VAH during follow-up.CONCLUSION: We tried to figure out the VA diameter change after VAD event and observed that the VA diameter could show dynamic change on its diameter and this could mimic the VAH on the initial imaging study.

SE 09 NR-31Diffusion tensor MR imaging in chronic spinal cord injurySharath Babu Indian College of Radiology, India. sharathshaswath@gmail.com

PURPOSE: To characterize the diffusion properties of the entire human spinal cord in vivo during the chronic stages of spinal cord injury. Diffusion tensor MR imaging is emerging as an important tool for displaying anatomic changes in the brain after injury or disease but has been less widely applied to disorders of the spinal cord and chronic stages of spinal cord injury. Data provide insight into the structural changes that occur as a result of long-term recovery from spinal trauma.M AT E R I A L S A N D M E T H O D S : 2 0 c a s e s o f neurologically intact subjects and 10 subjects with chronic were enrolled in this study. A single-shot twice-refocused spin-echo diffusion-weighted echo-planar imaging pulse sequence was used to obtain axial images throughout the entire spinal cord in less than 60 minutes.RESULTS: Despite heterogeneity in chronic stages of spinal cord injury lesion severity and location, diffusion characteristics of the chronic lesion were significantly elevated compared with those of uninjured controls. Fractional anisotropy was significantly lower at the chronic lesion and appeared dependent on the completeness of the injury. Conversely, mean diffusivity measurements in the upper cervical spinal cord in subjects with chronic stages of spinal cord injury were significantly lower than those in controls. These trends suggest that the entire neuraxis may be affected by long-term recovery from spinal trauma.CONCLUSION: These results suggest that diffusion tensor imaging may be useful in the assessment of chronic stages of spinal cord injury.

SE 09 NR-32Unruptured intracranial aneurysms presenting with ischemic strokeMin Kyung Jung, Won-Sang Jung, Yon-Kwon Ihn The Catholic University of Korea, St. Vincent's Hospital, Korea. ihn@catholic.ac.kr

Intracranial aneurysms uncommonly present with ischemic stroke. Parent artery occlusion due to local extension of the luminal thrombus, aneurysms ejecting emboli to distal arteries, or increased mass effect have been described as possible pathogenic mechanisms. Guidelines for the management of these patients are absent. We report three cases of unruptured intracranial aneurysms manifesting with ischemic stroke. All patients demonstrated acute ischemic lesion in the symptomatic territory with diffusion restriction on diffusion weighted image (DWI). All patients also demonstrated a nodular lesion at the acute ischemic area on T2 weighted image (T2WI). These nodular lesions showed dark signal intensity with blooming on susceptibility weighted image (SWI), representing thrombi. All aneurysms were located on the middle cerebral artery. Two aneurysms (with 11-20 mm in size) were completely thrombosed. One aneurysm (with 47 mm in size) was partially thrombosed. Two patients were referred for clipping. One patient was on medication and observed. Medically treated two patients had a favorable outcome but one patient with clipped giant aneurysm had serial seizure episodes. Awareness of this unusual presentation with ischemic stroke of unruptured intracranial aneurysms is important for early diagnosis and treatment. The purpose of this presentation is to emphasize on including diagnosis of ischemic stroke due to unruptured aneurysms, especially in acute infarction accompanied with a nodular lesion which shows dark signal intensity with blooming on SWI.

SE 09 NR-33The MR characteristics of enhancement of facial nerves in patients with Bell’s palsy Bo Ra Yoon, Eui Jong Kim, Hyug Gi Kim, Kyung Mi Lee, Woo Suk Choi Kyung Hee University Medical Center, Korea. euijkim@hanmail.net

PURPOSE: To evaluate the diagnostic performance of Gd-enhanced magnetic resonance (MR) image for Bell’s palsy, we investigated enhancement pattern and signal intensity (SI) of facial nerves. And we also compared image findings to clinical grading for facial neuropathy.MATERIALS AND METHODS: The study included 92

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facial nerves in 46 patients (M:F = 13:33; mean age, 51.46) who were diagnosed as Bell’s palsy from March 2014 to April 2016. Contrast enhanced T1-weighted MR image was acquired on a 3T MR system with the following parameters: TR/TE = 450/10 ms, and voxel size = 0.71 x 0.86 x 2.00 mm3 without slice gap. We retrospectively reviewed the facial nerves according to the conventional anatomical classification. We calculated the SI ratio of diseased facial nerve to normal one in the same patient, and called it “relative Contrast enhanced SI (rCE SI [%]). We also investigated difference between the number of continuous enhanced segments, and other features such as nerve bulging. The House-Brackmann (HB) score was used for clinical investigation. Statistical analyses were conducted by using MedCalc statistical software.RESULTS: Of the 46 patients with Bell’s palsy showed more enhancement at diseased facial nerves than normal. The rCE SI (%) of five segments represented by median value was calculated, respectively: 1. Cannalicular = 83.08%, 2. Labyrinthine = 50.17%, 3. Genu = 54.71%, 4. Tympanic = 36.35% and 5. Mastoid = 16.03%). The result showed the prominent enhancement difference between diseased nerve and normal one at all the segments, with statistically significant differences (for cannalicular to tympanic, p < 0.0001, and for mastoid segment, p = 0.0050). Especially the rCE SI of proximal part (cannalicular, labyrinthine, and genu segments) was higher than distal part (tympanic, and mastoid segments) as known usually enhanced in the normal facial nerve. The length of diseased facial nerve was longer than normal one, with statistically significant difference (median value 5 for diseased nerves and 2 for normal nerve, p < 0.0001). Morphologic change of diseased facial nerve appeared on genu as bulging (16/46, 34.80%). However, there was no statistically association between the HB grade and image characteristics.CONCLUSION: The rCE SI, the length of enhancement, and bulging of genu on contrast enhanced MR images showed superior diagnostic performance to only quantitative investigation.

SE 09 NR-34Traumatic pseudoaneurysm of the superficial temporal artery treated by endovascular coil embolizationYon-Kwon Ihn1, Won-Sang Jung1, Bum-soo Kim2 1The Catholic University of Korea, St. Vincent's Hospital, 2The Catholic University of Korea, Seoul St. Mary's Hospital, Korea. ihn@catholic.ac.kr

Although pseudoaneurysm of the superficial temporal

artery (STA) are very rare, it is well known that any blunt or penetrating trauma on the side of the head may result in a STA pseudoaneurysm. We present two cases of traumatic pseudoaneurysm of the superficial temporal artery (STA), which were located at anterior branch of the STA and the proximal STA. These aneurysms were treated with microcoil embolization of the STA. We conclude that endovascular coil embolization can be an viable option in the treatment of STA pseudoaneurysm.

SE 09 NR-35Pictorial review of acute intraparenchymal hemorrhage of various etiology: beyond hypertensive intracerebral hemorrhageByung Hyun Baek1, Woong Yoon1, Seul Kee Kim2, Yun Young Lee2 1Chonnam National University Hospital, 2Chonnam National University Hwasun Hospital, Korea. radyoon@jnu.ac.kr

PURPOSE: 1. To illustrate the various causes and clinical manifesta-

tions of intracerebral lobar hemorrhage.2. To identify diagnostic key imaging findings of unusual

hemorrhagic stroke of various cause with CTA, MRI, conventional angiography.

3. To determine strategy for further evaluation and predict prognosis.

CONTENT ORGANIZATION: 1. Overview of etiology and epidemiology of intracerebral

hemorrhage.2. Review of various causes of acute lobar hemorrhage

and their characteristic imaging features beyond hypertensive hemorrhage.- Cerebral amyloid angiopathy- Vascular malformations (arteriovenous malformation,

cavernous angioma)- Other vascular origins (arterial infarction, ruptured

huge aneurysm, dural sinus or cortical vein thrombosis, dural AV fistula)

- Neoplasms- Coagulopathy or rt-PA related hemorrhage- Infectious origins (paragonimiasis, mycotic

aneurysm)- Inflammatory origins (CNS vasculitis)- Etc. (moyamoya disease, ADEM, PRES, remote

cerebellar hemorrhage)CONCLUSION: When we encounter acute lobar hemorrhage, it is vital for the neuroradiologist to be aware of possibility of underlying pathology. Correlation of imaging findings with clinical presentation can help establish the correct diagnosis of acute lobar hemorrhage of various etiology.

582 KCR 2016

Neuroradiology

SE 09 NR-36Variable appearance of meningioma: case series and review of the literatureHwayoung Song1, Eun Soo Kim1, Mi Jung Kwon1, Yul Lee1, Kwan Seop Lee1, Jin Hee Moon1, Hye Jeong Kim2 1Hallym University Sacred Heart Hospital, 2Kangnam Sacred Heart Hospital, Korea. silwater007@naver.com

Meningioma is the most common con-glial tumor of the central nervous system (CNS). The typical features of meningioma are very well known in image modalities such as CT and MRI, which are available of accurate diagnosis however the diagnostic difficulties incur when there is a number of atypical meningioma. We tried to show the unique aspects of the eight meningioma cases. The characteristic image findings of meningioma are reported as most benign, convex shaped, extra-axial location, homogeneous signal intensity and strong enhancement on MRI, mass effect at brain and hyperostosis. Unusual findings in our cases have been misdiagnosed as other tumors, thrombosis and inflammation due to unfamiliar location, signal intensity, enhancement pattern, and unique presentation. The purpose of our study was to characterize the clinical and imaging feature of unusual meningioma and to improve recognition and understanding of this entity.

SE 09 NR-37The difference of functional connectivity depending on duration of mild cognitive impairment in Parkinson disease: focusing the substantia innominataInjoong Kim1, Na-Young Shin2, Soo Mee Lim2 1VHS Medical Center, 2Ewha Womans University School of Medicine, Korea. nyshin@ewha.ac.kr

PURPOSE: Degenerative change of the nucleus basalis of Meynert (NBM) which is a group of neurons in the substantia innominata (SI) of the basal forebrain begins in the early stages of Parkinson disease (PD) and is known to be significantly correlated with cognitive performance. We aimed to evaluate the different patterns of functional changes of SI in patients with PD with mild cognitive impairment (MCI) according to the duration of parkinsonism before mild cognitive impairment using resting state functional magnetic resonance imaging (rsfMRI).MATERIALS AND METHODS: Fifty-four patients with PD-MCI were classified into 2 groups on the basis of shorter (< 1 year, n = 27) and longer (≥ 1 year, n =

27) durations of parkinsonism before mild cognitive impairment. Thirty four age- and sex-matched drug-naïve PD patients with intact cognition (PD-IC) were included for comparison. Seed-based resting state functional connectivity (rsFC) analysis using bilateral SI as the seed was performed. Age, sex, years of education, age at onset of parkinsonism, and levodopa-equivalent dose were included as covariates.RESULTS: PD-MCI-SD group exhibited decreased rsFC in the both frontal areas, when compared with the PD-IC group as well as PD-MCI-LD group. On the contrary PD-MCI-LD group exhibited decreased rsFC in bilateral primary motor sensory area and occipital area, when compared with the PD-IC group and PD-MCI-LD group. Moreover, Spearman’s correlation analysis showed significant associations between shorter disease duration and decreased rsFC in the both frontal areas.CONCLUSION: The changes in rsFC of the SI may topographically differ depending on the rate of cognitive decline in patients with PD-MCI. Decreased rsFC between the SI and both frontal areas might be associated with early cognitive decline in patients with PD-MCI-SD.

SE 09 NR-38The role of DWI or ADC map for the diagnosis of neurosurgical site infectionSoo hyun Kim, Sam-Soo Kim, Hye-Kyung Yoon Kangwon National University Hospital, Korea. samskim@kangwon.ac.kr

PURPOSE: To review DWI characteristics within complicated fluid collection in patients with postoperative infection in order to determine that DWI could be used as a single imaging sequence for the diagnosis of neurosurgical site infection.MATERIALS AND METHODS: We retrospectively reviewed MR imaging including DWI in 35 patients with neurosurgical site infections after craniotomy, craniectomy or cranioplasty over five-year period. The diagnosis was made on the basis of clinical and imaging findings and confirmed by exploration. Signal-intensity characteristics of complicated fluid and dura around the surgical bed on conventional MR images and DWIs were evaluated. In seven patients, ADC values of the lesions were calculated by using two b values (b = 0, 1000 s/mm2).RESULTS: In the 7 postoperative infection patient, almost patients (3/7) was subdural hyperintense or mixed hyperintensity and hypointensity on DWIs. The subset of patients with postoperative infection exhibited evidence of restricted diffusion in 4 out of 7 (57%) patients. In the remaining patient (3/7, 43%), there was no restricted diffusion in the complicated fluid

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collection of subdural or epidural space such as epidural empyema. Notably, the region of the restricted diffusion was in complicated fluid collection covered cranioplasty site in all cases.CONCLUSION: Signal intensity of infected fluid on DWI was variable and low ADC values were shown in more than half cases with neurosurgical site infections. Nevertheless, DWI with ADC map should not be used as a sole imaging sequence for the diagnosis of neurosurgical site infections since there were cases without restricted diffusion.

SE 09 NR-39 This is not an inverted papillomaSaehyung Lee, Yunsup Hwang, Young-Joo Kim, Kitae Kim The Catholic University of Korea, Uijeongbu St. Mary's Hospital, Korea. violet2@catholic.ac.kr

Inverted papilloma is a benign epithelial neoplasm that arises within the nasal vault and, less commonly, in the paranasal sinuses. Although the CT appearance of inverted papilloma is variable and non-specific., inverted papilloma is the most likely diagnosis when a unilateral mass with enhancement in the nasal vault, producing benign bony changes, extends centrifugally in an elderly patient with chronic nasal obstruction.We will overview imaging findings of inverted papilloma and mimickers ( including sinonasal polyposis, inflammatory polyps, fungal sinusitis, hemangioma, juvenile angiofibroma, sinonasal squamous cell carcinoma, adenoid cystic carcinoma, and lymphoma), and discuss differential points to help discriminate among these sinonasal tumors, that should not be mistaken.

SE 09 NR-40MR findings of various diseases involving the thalamus Kanghun Lee, Yunsup Hwang, Young-Joo Kim The Catholic University of Korea, Uijeongbu St. Mary's Hospital, Korea. violet2@catholic.ac.kr

The thalamus is important structure that has several functions including processing of sensory signal and relaying it to the relevant cortex, differentiation of the functioning of recollective and familiarity memory, and regulation of sleep and wakefulness executive functions. In various diseases, thalamic involvement on MR image is typically or occasionally demonstrated,

and that can help the radiologist to make diagnosis and differentiation. We herein review the MRI characteristics of the variable thalamic lesions. They include vascular lesion (arterial and venous infarction, hemorrhage), calcification, metabolic disorder (osmotic demyelinating syndrome, Wernike encephalopathy, posterior reversible encephalopathy), inflammatory disease (Behcet disease), tumor (glioblastoma multiforme, gliomatosis cerebri, lymphoma), and infection (encephalitis, progressive multifocal leukoencephalopathy, Creutzfelt-Jacob disease). Familiarity with imaging finding of various thalamic lesions should avoid misdiagnosis and erroneous patient management.

SE 09 NR-41 Hypoxic-ischemic encephalopathy in the neonate: diagnosis by cranial ultrasound and correlation with MR Arim Pak, Sang il Suh, Inseon Ryoo, Hae-Young Seol Korea University Guro Hospital, Korea. ssickh@korea.ac.kr

Hypoxic-ischemic encephalopathy (HIE) in the neonatal period requires early detection for effective management. Cranial ultrasonography (cUS) is the primary screening technique for neonatal HIE, easy accessible and non-invasive. Careful interpretation of sequential cUS is important because mild HIE may be appeared as increased white matter echogenicity only, which can be easily overlooked. On the other hand, severe HIE is detected effectively by cUS and the findings are well correlated to that of brain MRI.We illustrate our hospital’s HIE cases by focusing on characteristic pattern of cUS findings which is varying according to severity of hypoxic damage and patient’s gestational age (GA), and correlation between findings of early cUS screening and those of follow-up cUS and brain MRI.We described as following category: Gestational age (1. Very preterm infants [GA at or below 32 weeks], 2. Late preterm infants [GA between 34 weeks and 36 weeks and 6 days], 3. Early term and term infants [GA 37 to 42 weeks]), severity of hypoxic damage (1. Mild, 2. Moderate to severe) with emphasis on correlation of sequential cUS and brain MRI. We presented possible underlying mechanism of these radiologic patterns of HIE. In addition, we discussed equivocal findings during initial neonatal cUS screening in daily practice which should be keep in mind for careful follow-up.

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Neuroradiology

SE 09 NR-42Hypoxic-ischemic encephalopathy: susceptibility weighted imaging findingsSaehyung Lee, Yunsup Hwang, Young-Joo Kim, Kitae Kim The Catholic University of Korea, Uijeongbu St. Mary's Hospital, Korea. violet2@catholic.ac.kr

INTRODUCTION: In susceptibility-weighted imaging (SWI) in the normal brain, cortical and medullary veins appear hypointense due to paramagnetic properties of deoxyhemoglobin. SWI abnormalities in the hypoxic-ischemic encephalopathy (HIE) might represent the cerebral metabolic stress causing the varying amounts of deoxyhemoglobin in cerebral veins. Our aim was to assess the predictive value of SWI for outcome in HIE. MATERIAL AND METHODS: We studied SWI and diffusion imaging in patients with comatose after cardiac arrest. Qualitative scores based on venous visibility were assigned on a prominence of vein (POV) scale respectively as 3 groups: low/intermediate/high. We analyzed the association of the degree of POV on SWI with clinical data and MR markers. The Cerebral Performance Category (CPC) was used as a clinical outcome score. RESULTS: Forty-eight HIE patients were included in this study. Mean age at MR imaging from onset was 3.4 days (range, 0-7 days). There is no difference in MR time from onset between groups. Patients with low (29 patients) and high (9 patients) POV on SWI Patients with intermediate POV had significantly lower CPC score than patients with low POV patients or high POV patients (p < 0.005). No significant differences between the low POV patients and high POV patients were observed in the CPC score (p = 0.326). CONCLUSION: Abnormal low and high vein scores indicate abnormal levels of deoxyhemoglobin and correspond to poor clinical outcomes in HIE.

SE 09 NR-43Alteration of functional networks in postpartum women: task-based and resting-state fMRIYunjin Bak1, Yoonjin Nah2, Soo mee Lim1, Na-Young Shin1 1Ewha Womans University School of Medicine, 2Yonsei University, Korea. nyshin@ewha.ac.kr

PURPOSE: To investigate neural correlates underlying cognit ive deficiency in Postpartum women, we conducted task fMRI experiment using simple cognitive task.

MATERIAL AND METHODS: 24 women in postpartum periods and 27 controls participated in the study and performed N-back task varying cognitive load (0, 1, 2-back) during fMRI data acquisition. We investigated task-induced fMRI signal to examine altered neural process associated wi th cogni t ive demand in Postpartum. BOLD activity during fixation periods, interleaved with task blocks, were also examined. To explore group differences in intrinsic activity between PP and control, ALFF and fALFF values were calculated in resting-state fMRI data. Since activation results indicated that Postpartum has altered activation patterns in brain regions belonging to either default mode network (DMN) or task positive network (TPN), further network analysis was performed by calculating pairwise correlation coefficients between neural nodes within these networks.RESULTS: Behaviorally, Postpartum exhibited slower response times for the working memory task relative to control. For task-related fMRI results, bilateral dlPFC in Postpartum showed greater activation throughout the N-back task compared to control. We also found significant group (postpartum vs. control) by cognitive load (0-back vs. 1-back vs. 2-back) interaction in ACC and Insula/Putamen, and these regions with dlPFC belong to TPN. Relatively decreased activation in mPFC, known as main node of DMN, for Postpartum than control was found during fixation periods. Similarly, resting-state fMRI analysis resulted in deactivation of dorsal area of mPFC in Postpartum. In network analysis, we found elevated connectivity within TPN in Postpartum than control.CONCLUSION: These results suggest that disrupted cognitive process in Postpartum is related to altered functioning of cognitive networks.

SE 09 NR-44Cerebral CT angiography using a 70 kVp and low volume of low-concentration contrast mediaYun Jung Choi, Eun-Suk Cho, Junyoung Kim, Jeong Min Choi Gangnam Severance Hospital, Korea. jjondol@hanmail.net

PURPOSE: Contrast-induced acute kidney injury (CIAKJ) is related to the volume, osmolality, and viscosity of iodinated contrast media (CM). Therefore, we performed cerebral CT angiography (CTA) using low volume of low-concentration CM (LC-CM) with iso-osmolality and lower viscosity and applied (a low tube voltage of) 70 kVp and iterative reconstruction to increase arterial attenuation and contrast-to-noise ratio (CNR). Finally, we compared 70 kVp with low volume of LC-CM and 100 kVp with low volume of

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high-concentration CM (HC-CM), regarding arterial attenuation, CNR, image quality and radiation dose.MATERIALS AND METHODS: Attenuation value and CNR were determined in a head phantom for two tube voltages (70 and 100 kVp) and two different CM (LC-CM and HC-CM). Among 13 volunteers, 6 were scanned using a 70 kVp and 40 mL of LC-CM (iodixanol 270; osmolality of 290 mosm/kg H2O, viscosity of 6.3 mPa‧s at 37°C), and the others were scanned using a 100 kVp and 40 mL of HC-CM (iohexol 350; osmolality of 844 mosm/kg H2O, viscosity of 10.4 mPa‧s at 37°C). The attenuation value and CNR of cerebral arteries, subjective image quality, and radiation dose were compared between two groups.RESULTS: Mean attenuations of cerebral arteries and CNR were significantly higher in 70-kVp with LC-CM (364.2 ± 50.2 HU, 25.0 ± 4.3, respectively) than 100-kVp with HC-CM (391.4 ± 94.1 HU, 17.6 ± 4.4, respectively). 70-kVp protocol had significantly higher quality scores in arterial enhancement, sharpness of the artery and image noise compared to 100-kVp protocol. An effective dose of 70-kVp was 10% lower than that of 100-kVp.CONCLUSION: The use of 70-kVp with LC-CM could improve arterial enhancement and CNR, and provide superior subjective image quality using lower radiation dose than 100-kVp with HC-CM. Furthermore, the LC-CM protocol may reduce the risk of CIAKJ by using CM with iso-osmolality and lower viscosity.

SE 09 NR-45Lens exposure in CT brain: a commonly underestimated radiation health hazardChun Lee Queen Mary Hospital, Hong Kong, China. bruce1984@hotmail.com

BACKGROUND: In this era with ever increasing number of CT brain being performed for the patients, the reduction of the lens dose from the standard brain CT examination has become paramount importance. The likelihood of lens damage subsequently leading to cataract formation has always been underestimated or neglected. From many large scale studies, cataracts remain the major cause of blindness and visual impairment which contributes to more than 90% of the total disability adjusted life years.PURPOSE: To introduce a new scanning protocol which minimizes lens irradiation with preserved diagnostic quality and to identify exclusion factors to this protocol.MATERIALS AND METHODS: Out of 100 consecutive brain scans, record the number of cases in which the lenses of one or both eyes were included in the field of examination together with review of the scanning plane used. Subsequent introduction of the new

supraorbitomeatal plane was made and the percentage of lens exclusion and total image slices were both compared with the previous protocol. Evaluation of image quality from two scanning protocols was also performed by two experienced neuroradiologists using a checklist system. Potential exclusion factors to the new scanning protocol were explored to determine the actual clinical applicability.RESULTS: The percentage of the CT brain scans in which at least one of the lens were included had a drastic reduction from 98% to 14% after first implementation of the new supraorbitomeatal plane as compared to the conventional orbitomeatal plane, which was previously found to be the most common plane used by the radiographers. Overall dose reduction was also achieved by an average reduction of 1 image slice with the new protocol. The image quality from the new protocol was reported to be satisfactory. Exclusion factors to this new protocol include uncooperative patient, clinical emergency and conditions which prevent neck flexion, which amount to 12% of the total cases.CONCLUSION: The new and s imple to learn supraorbitomeatal plane with lens exclusion was proven to be excellent in lens dose reduction with preserved image diagnostic quality and few exclusion factors. Overall CT brain dose reduction can also be achieved via average reduction of 1 image slice.

SE 09 NR-46 Clinical and radiologic manifestations of cerebral vein and venous sinus thrombosisJung Ho Jang, Dae Seob Choi Gyeongsang National University Hospital, Korea. choids@gnu.ac.kr

OBJECTIVE: Cerebral vein and venous sinus thrombosis (CVST) is a rare disease, but can be life-threatening. Because of variety in clinical and radiological manifestations, it is difficult to diagnose and treatment could be delayed in clinical practice. We aimed to investigate clinical presentations and radiologic findings in patients with CVST.METHODS: From the recent ten years data base of our institution, we found forty-four patients who were diagnosed having cerebral venous sinus thrombosis on CT venography (CTV, n=23), MR venography (MRV, n=9), digital subtraction angiography (DSA, n=5), CTV + MRV (n=4), MRV + DSA (n=2) and SWI MR (n=1), respectively. We retrospectively reviewed their clinical presentations and MR or CT findings. There were 21 males and 22 female, aged range 10 months to 89 years.RESULTS: The initial clinical presentations of the patients were headache in 20 (46.5%), followed by

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weakness of their limbs in 11 (25.6%), seizure in 6 (14%), trauma-related in 4 (9.3%), psychosis in one (2.3%) and no neurologic symptom in one (2.3%), respectively. On CT and/or MR imaging, there were intracranial hemorrhage (59%, SAH=10, ICH=7, SDH=2, micro-bleed=2, ICH+SAH=1, ICH+SDH=1, ICH+SAH+SDH=1 and SAH+SDH+IVH=1), high signal intensity in T2/FLAIR and DWI (20.9%) and no specific finding (20.9%). Superior sagittal sinus was commonly involved 61.4% of patients, followed by transverse sinus (54.5%), sigmoid sinus (40.9%), cortical vein (38.6%) and straight sinus (20.5%), respectively.CONCLUSION: As shown in our study, CVST were presented with diverse clinical and radiological manifestations. It might be confusing with acute infarction and intracranial hemorrhage. Therefore, the knowledge of clinical and radiologic findings and diagnostic suspicion of CVST will be helpful for its early diagnosis and treatment in clinical practice.

SE 09 NR-47 rCBV of gliomas: do they reflect the level of neoangiogenesis and help in preoperative tumor grading?Preetham Pantrangam1, Ajay Krishna Karnati1, Vikram Mungamuru2, Sridhar Devu2 1Krishna Institute of Medical Sciences (KIMS), Nellore, Andhra, 2Yashoda Hospital, Somajiguda, Hyderabad, India. preetham1783@gmail.com

PURPOSE: To study the perfusion MR characteristics of tumor quantitatively in the form of tumor rCBV and peritumoral rCBV of gliomas. Correlation of perfusion characteristics with the neovascularity of tumor and histopathological grade of malignancy.MATERIALS AND METHODS: We evaluated 106 patients prospectively for a period of 3 years with gliomas. The perfusion scan was performed with a gradient-echo EPI sequence, following a single dose of IV injection of MR contrast at a rate of 5ml/s in the antecubital vein using a power injector. Perfusion MR imaging was performed and post-processing for the evaluation of perfusion parameters was done. The ROI’s were placed in the region with maximum perfusion in the tumor bed and in the peritumoral edema. Post-operatively the tumor biopsy specimens were studied for tumor neoangiogenesis and Grading the tumor.RESULTS: There were a total of 106 gliomas in our study of which 47 were low grade gliomas (WHO grade I & II) and 59 were high grade gliomas (WHO grade III & IV ). The rCBV’s of high grade gliomas were in the range of 1.6 to 8.3 and low grade gliomas were in the range of 0.8 to 2.1, with a mean rCBV of 1.5 ± 0.4 in low

grade gliomas and 3.53 ± 2.2 in high grade gliomas. The rCBV’s of peritumoral edema of the Low grade gliomas had a range of 0.6 to 1 with a mean rCBV of 0.76 ± 0.2 and high grade gliomas had a range of 0.7 to 9 with a mean of 2.19 ± 2.6.CONCLUSION: The measurement of mean tumor rCBV and peritumoral rCBV values derived from perfusion MR maps yields information about tumor vascularity and neoangiogenesis which is useful in differentiating low from high grade gliomas, which help in the pre-operative and post-operative treatment planning, stereotactic biopsy guidance, monitoring response to therapy and thus giving better prognostic outcomes.

ANAPLASTIC ASTROCYTOMA (WHO GRADE III)

SE 09 NR-48 Uremic encephalopathy: MR imaging findings and clinical correlationDa Mi Kim, In Ho Lee, Chang June Song Chungnam National University Hospital, Korea. leeinho1974@hanmail.net

BACKGROUND AND PURPOSE: Uremic encephalopathy is a metabolic disorder in patients with renal failure. The purpose of this study was to describe the MR imaging findings of uremic encephalopathy.MATERIALS AND METHODS: This study retrospectively reviewed MR imaging findings in 10 patients with clinically proved uremic encephalopathy between May 2005 and December 2014. Parameters evaluated were lesion location and appearance; MR signal intensity of the lesions on T1WI, T2WI, and T2 fluid-attenuated inversion recovery images; the presence or absence of restricted diffusion on diffusion-weighted images and apparent diffusion coefficient maps; and the reversibility of documented signal-intensity abnormalities on follow-up MR imaging.RESULTS: MR imaging abnormalities accompanying marked elevation of serum creatinine (range, 4.3-11.7 mg/dL) were evident in the 10 patients. Nine patients had a history of chronic renal failure with expansile

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bilateral basal ganglia lesions, and 1 patient with acute renal failure had reversible largely cortical lesions. Two of 6 patients with available arterial blood gas results had metabolic acidosis. All basal ganglia lesions showed expansile high signal intensity (lentiform fork sign) on T2WI. Varied levels of restricted diffusion and a range of signal intensities on DWI were evident and were not correlated with serum Cr levels. All cortical lesions demonstrated high signal intensity on T2WI. Four patients with follow-up MR imaging after hemodialysis showed complete resolution of all lesions.CONCLUSIONS: The lentiform fork sign is reliable in the early diagnosis of uremic encephalopathy, regardless of the presence of metabolic acidosis. Cytotoxic edema and/or vasogenic edema on DWI/ADC maps may be associated with uremic encephalopathy.

SE 09 NR-50Various imaging features of intracerebral mimicking lesionsNa rae Kim, In Kyu Yu Eulji University Hospital, Korea. knrr1212@naver.com

PURPOSE:1. To review various confusing imaging features which

mimicking between tumors and tumor-like lesions of the brain.

2. To learn differential diagnostic clues and to prevent misdiagnosis between tumors and tumor-like lesions.

CONTENT ORGANIZATION:1. Non-tumorous lesions, mimicking tumor

1) Inflammation and vasculitis(1) Multiple sclerosis(2) Neurosarcoidosis(3) Neuro-Bechet disease(4) Inflammatory (pituitary) pseudotumor

2) Infection(1) Septic embolic infarct(2) Invasive sinusitis

3) Stroke (hemorrhagic or venous)(1) Encapsulated chronic ICH(2) Venous infarction

2. Tumors, mimicking non-tumorous lesion1) Tumor, mimicking recent infarction

Low-grade glioma2) Tumor, mimicking inflammatory granuloma

(1) Anaplastic astrocytoma(2) Malignant lymphoma

3) Tumor, mimicking encephalitisGliomatosis cerebri

CONCLUSION:1. Understanding differential diagnosis which mimicking

lesions on imaging findings can be helpful for

classifying between both entities.2. Review MR imaging correctly with integrating multiple

modalities and consider clinical information (symptom onset, progression), can help radiologist for accurate diagnosis.

SE 09 NR-51 Various spectrum of uncommon normal variations of cerebral arteries confirmed by catheter angiography or CTA, MRANa rae Kim, In Kyu Yu Eulji University Hospital, Korea. knrr1212@naver.com

PURPOSE:1. To introduce various uncommon normal variation

of cerebral arteries from reviewing angiography on TFCA, CTA and MRA.

2. Get knowledge of imaging findings about normal variation of cerebral arteries and prevent iatrogenic injuries during neurovascular procedures.

CONTENT ORGANIZATION: 1. Brief overview of the development of cranial arterial

anatomy2. Common normal variation

1) Hypoplasia2) Primitive artery3) Azygos type of ACA4) Early bifurcation of MCA5) Fenestration

3. Un-common normal variation1) Agenesis of ICA2) Infraoptic ACA3) Multiple segmental duplication

CONCLUSION: Get awareness of the anatomical variation of cerebral arteries which is uncommon can be helpful for the evaluation of angiographic findings.

SE 09 NR-52Cerebral infections and immunodeficiencyJoachim Son, Philippe Maeder, Reto Meuli University Hospital of Lausanne, University of Lausanne, Switzerland.j@joachimson.com

LEARNING OBJECTIVES: To know the etiologies, the semiology and the pathogenicity of brain infections in immunosuppressed patients. To know the adequate sequences to use with MRI and the limits of CT scan. To know some challenging complications of immune deficiency linked with brain infections and main differential diagnoses.

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BACKGROUND: Brain infections in immunosuppressed patients are opportunist infections occurring also in HIV. Their prevalence increased dramatically in the last three decades with the treatment of oncologic diseases and transplantation development. In our series at University hospital of Lausanne, they occurred after chemotherapy, corticotherapy, in diabetes (by a reduction of NK cells with hyperglycemia) or organ transplant.IMAGING FINDINGS: The most frequent cerebral infections found in altered immunity are brain abscesses due to toxoplasmosis, aspergillosis, candidosis, cryptococcosis, nocardiosis, pyogenic germs, and tuberculosis. They may be identified with MRI at 1.5T and 3T by post-gadolinium annular enhancement, restricted diffusion, peripheral edema with T2 and FLAIR hypersignal, and central necrosis. Aspergillosis abscesses may present signs of bleeding found on SWI/T2* sequences or through spontaneous T1 hypersignal. Non pyogenic abscesses and pyogenic abscesses after antibiotic treatment can fail to elicit restricted diffusion signal. MR spectroscopy can show lactate and aminoacids peaks helping to differentiate brain abscesses from necrotic metastases. Perfusion imaging can increase the reliability of the diagnosis. Empyemas are less frequent but are often seen in immunosuppressed patients. Such as in immunocompetent patients, some cases of viral encephalitis (VZV, HSV) are observed, with complex differential diagnoses including limbic encephalitis, challenging the treatment and patient’s outcome. EBV-induced lymphoma and PML (progressive multifocal leukoencephalopathy due to JC virus) and PML in the context of and IRIS (immune reconstitution inflammatory syndrome) can occur during episodes of modulated immunity.CONCLUSION: Situations such as chemotherapy, organ transplant, metabolic diseases such as diabetes, may lead to brain infections, mainly brain abscesses. MRI is a sensitive exam and must include T2, FLAIR, DWI and post gadolinium T1 sequences. For better specificity, perfusion, spectroscopy and gradient echo sequences may be included. CT stays role is limited, especially at the early stage of the disease.

SE 09 NR-53Comparison of 3D DIR with 3D T1W images in gray matter volume losses in patients with AD and MCIYeji Shin1, Dong Kyun Lee2, Hak Young Rhee1, Soonchan Park1, Chang-Woo Ryu1, Geon-Ho Jang1, Jong-Min Lee2, Eui-Jong Kim3, Woo-Suk Choi3 1Kyung Hee University Hospital at Gangdong, 2Hanyang University, 3Kyung Hee University Medical Center, Korea. ghjahng@gmail.com

INTRODUCTION: A three dimensional (3D) T1-weighted (T1W) image is usually used to evaluate regional gray matter volume (GMV) differences between controls and Alzheimer’s disease (AD) patients. A 3D double inversion recovery (DIR) image is obtained with simultaneously suppressing the signals from both cerebrospinal fluid (CSF) and normal white matter in the brain, allowing better visualization of the remaining tissues. DIR reduces partial volume effects of gray matter with white matter and CSF.PURPOSE: To prospectively investigate the comparison between 3D DIR and 3D T1W images to evaluate alterations of GMV between AD patients and cognitively normal (CN).MATERIALS AND METHODS: We included 25 subjects with mild or probable AD, 25 subjects with amnestic mild cognitive impairment (MCI), and 25 elderly CN subjects. Group differences for each technique in GMV among CN, MCI, and AD patients were tested by voxel-wise, one-way ANOVA. Additional region-of-interest-based comparisons of GMV differences among the three groups for DIR and T1WI were performed using ANCOVA. Finally, ROC curve analysis was performed.RESULTS: In the AD group compared with the CN and MCI groups, GMV was decreased in both DIR and T1W images. However, the areas showing GMV loss were larger in DIR images compared to those in T1W images. The main areas showing GMV loss in the AD group compared with the MCI group were as follows: the left superior and middle temporal gyrus, and the right and left parahippocampal gyrus. Amygdala had the highest area under curve (AUC) value for both DIR and T1W images.CONCLUSION: DIR images were sensit ive for identifying GMV loss in patients with AD compared with MCI and CN subjects and areas showing GMV loss identified with DIR were extended to more brain areas than those identified with T1W. With DIR, amygdala GMV is the most sensitive in differentiating between subject groups.

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Neuroradiology (H

N)

SE 09 NR-54 Quantitative analysis of CT perfusion parameters with histogram of various brain tumors by semi-automated segmentationSoo young Chae, Sangil Suh, Inseon Ryoo, Arim Park, Hae Young Seol Korea University Guro Hospital, Korea. sangil.suh@gmail.com

PURPOSE: The purpose of this study is to assess the feasibility of segmentation of brain tumors using semi-automated segmentation using Graph-Cut algorithm method and to evaluate its clinical application by calculating volumetric CT perfusion values of various brain tumors.MATERIALS AND METHODS: Whole tumors were segmented by semi-automated segmentation using graph-cut algorithm and volumetric perfusion values of tumors were obtained; the arterial blood flow (AF) by maximum slope model, the equivalent blood volume (EBV) by Patlak plot, permeability of neoplastic vessels by Patlak plot and the ratio of permeability to EBV. Histogram anaylsis were done with kurtosis, skewness. Total 54 patients with brain tumors underwent preoperative whole brain CT perfusion (21 meningiomas, 8 glioblastomas, 3 high grade astrocytomas, 1 pilocytic astrocytoma, 1 pleomorphic xanthoastrocytoma, 6 lymphomas, 2 oligodendrogliomas, 3 ependymomas, 3 hemangioblastomas, 3 metastases and 3 other tumors).RESULTS: Semi-automated segmentation was feasible to successfully outline boundaries of tumors on perfusion maps. Meningiomas showed high EBV and high permeability. Median EBV of glioblastomas was significantly higher than that of lymphomas, which was well correlated with previous studies (p=0.02). Median ratio of permeability to EBV of glioblastomas was significantly lower than that of lymphomas (p=0.02).CONCLUSION: Semi-automated segmentation using graph-cut algorithm method can perform segmentation of whole tumor on CT perfusion maps and calculate volumetric perfusion values of brain tumors. Our preliminary study could provide basic perfusion values of whole volumetric tumors and further study will be needed to validate the segmentation method.

Neuroradiology (Head & Neck)

SE 10 NR(HN)-01 Traumatic pseudoaneurysm of the superficial temporal artery occurring in the frontal region: a case report and review of literatureSiew Kune Wong Singapore General Hospital, Singapore. sgh_wsk@hotmail.com

OBJECTIVES: To recognize that traumatic pseudoaneu-rysm of the superficial temporal artery can occur in the frontal region following blunt trauma. To review the pathophysiology of pseudoaneurysm formation and imaging diagnosis.BACKGROUND: Traumatic pseudoaneurysm of the superficial temporal artery is a very rare lesion and usually presents as a painless pulsatile mass in the temporal region a few weeks after trauma. An 87-year -old man was admitted from the accident and emergency department after a fall to the head. Initial CT brain was normal save for the presence of a left frontotemporal hematoma. Follow up MRI of the brain 2 weeks later reveals bilateral subdural hematoma formation and a focal enlarging mixed signal fluid collection in the left frontal region which was not initially recognized as a pseudoaneurysm. An ultrasound scan was then ordered as the patient developed a focal painless pulsatile mass in the left frontal region.IMAGING FINDINGS: Ultrasound shows turbulent flow within the focal swelling over the left frontal region giving a yin-yang sign on color Doppler consistent with a pseudoaneurysm. The feeding vessel was traced to the frontal branch of the left superficial temporal artery.CONCLUSION: This case illustrates that pseudoaneurysm of the superficial temporal artery should be kept in the list of differential diagnoses for a post-traumatic pulsatile soft tissue mass in the frontal region.

SE 10 NR(HN)-02 Value of early post-operative CT in predicting flap failure following head and neck cancer surgeryBitna Kim, Dae Young Yoon, Young Lan Seo, Eun Joo Yun Kangdong Sacred Heart Hospital, Hallym University, Korea. evee0914@chollian.net

PURPOSE: To identify the early post-operative computed tomography (CT) findings associated with flap failure following head and neck cancer surgery.MATERIALS AND METHODS: We retrospectively

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Neuroradiology - Informal Scientific PresentationPresenting

No.Final Abstract

No. Title Presenting Author

Page No.

ISP 05_NR 03 SE 09 NR-03

Radiology Resident Interpretations of diffusion-weighted MR imaging in the emergency department: is the diagnostic performance influenced by level of residency training?

Seung Jin Kim 568

ISP 03_NR 03 SE 09 NR-11 Assessment of collateral status with multiphase dynamic contrast-enhanced MR imaging Sanghyeon Kim 571

ISP 03_NR 01 SE 09 NR-17 ASL MR imaging: research and clinical applications and diagnostic pitfalls Dae Seob Choi 574

ISP 05_NR 01 SE 09 NR-19 Imaging of neurologic conditions during pregnancy and the postpartum period Yeon Su An 575

ISP 02_NR 01 SE 09 NR-20 High-Resolution MRI Vessel Wall Imaging: Changes in Atherosclerosis in Follow-up Period Young Jin Heo 575

ISP 02_NR 02 SE 09 NR-21Added value of high-resolution vessel wall MR imaging of intracranial vertebral artery dissection in planning of the endovascular treatment

Dong Gun Kim 575

ISP 03_NR 02 SE 09 NR-26 Diagnostic value of susceptibility- weighted images in cerebral venous thrombosis Hwa Seon Shin 578

ISP 02_NR 04 SE 09 NR-27 Unusual ruptured intracranial aneurysms: with interventional treatment Sung hoon Oh 578

ISP 05_NR 04 SE 09 NR-46 Clinical and radiologic manifestations of cerebral vein and venous sinus thrombosis Jung Ho Jang 585

ISP 05_NR 02 SE 09 NR-48 Uremic encephalopathy: MR imaging findings and clinical correlation Da Mi Kim 586

ISP 05_NR(HN) 01 SE 10 NR(HN)-11 Nasal cavity neoplasm and mimics: a pictorial review Yoo Kyung Nau 594

ISP 01_NR(HN) 01 SE 10 NR(HN)-12 Thyroglossal duct cyst: imaging characteristics and clinical correlation Seongsu Kang 594

ISP 01_NR(HN) 02 SE 10 NR(HN)-13 “Papilledema”: what the radiologist needs to know? Gun Su Kim 595

ISP 05_NR(HN) 03 SE 10 NR(HN)-17Sinonasal vascular mass lesions: a report of two rare differential diagnosis on MR imaging with clinicohistopathologic correlation

Christina Paola Pacpaco 597

ISP 01_NR(HN) 03 SE 10 NR(HN)-19 Dynamic susceptibility contrast perfusion MR imaging in the evaluation of parotid gland tumors Jeong Myeong Kim 598

ISP 01_NR(HN) 04 SE 10 NR(HN)-21CT Imaging Characteristics of lobular capillary hemangioma in the nasal cavity in comparison with cavernous or capillary hemangioma: clinical correlation

In Ho Lee 598

ISP 06_NR(NI) 01 SE 11 NR(NI)-03

Angiographic and clinical outcome in acute ischemic stroke patients treated with endovascular treatment beyond 6 hours from stroke onset: a propensity score-matched analysis

Jin Wook Baek 600

ISP 06_NR(NI) 02 SE 11 NR(NI)-04

Comparison of effectiveness and syfety between angioplasty and usual endovascular treatment for patients with anterior circulation acute ischemic stroke: a propensity score-matched analysis

Sang Soo Roh 600