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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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reviewed 60 patients who underwent flap reconstruction after head and neck cancer surgery and the early (≤ 14 days) post-operative contrast-enhanced CT scan. Patients were divided into two groups: flap failure (patients required reoperation for flap) (n = 18) and flap success (n = 42) groups. Clinical data (age, gender, type of flap, and time interval between operation and CT) and post-operative CT findings of flap (maximum dimension of flap, intra- or peri-flap fluid collection, intra- or peri-flap air collection, infiltration in fat within flap, fistula to adjacent aerodigestive tract or skin, and enhanced vascular pedicle) were assessed and compared between the two groups.RESULTS: Of the CT findings, intra- or peri-flap fluid collection > 4 cm (61.1% vs. 23.8%, p < 0.05), intra- or peri-flap air collection > 2 cm (61.1% vs. 2.4%, p < 0.0001), and fistula to adjacent aerodigestive tract or skin (44.4% vs. 0%, p < 0.0001) were observed significantly more frequent in the flap failure group. The maximum dimension, infiltration in fat within flap, and enhanced vascular pedicle were not found to be associated with flap failure.CONCLUSION: Early post-operative CT is useful in predicting flap failure following head and neck cancer surgery.

SE 10 NR(HN)-03Often avoided details in temporal bone imaging- elaborate anatomy and implications that radiologists must knowAruna Patil Apollo Hospital, India. dr.arunarpatil@gmail.com

INTRODUCTION: Petrous bone is a Pandora’s box lodging many structures including nerves, labyrinthine structures, muscles and ossicles. With the advent of HRCT, smaller canals, recesses and other structures can be easily identified provided the anatomy is known. Such detailed anatomical knowledge allows the radiologist to provide a precise report and hence aid in management planning.OBJECTIVES: 1. To acquaint the radiologist with the anatomy of the

smaller structures and often overlooked structures of temporal bone such as canals, muscles, labyrinthine apparatus and tympanic recesses.

2. Expand the scope of temporal bone reporting, providing precise details for better management.

3. These structures can be easily mistaken for fracture lines in case of trauma, abnormal soft tissue in case of infection/ inflammation. Some of these minute canals serve as a route of spread of disease. Recesses act as source for recurrence of otitis.

CONTENT ORGANIZATION: The anatomica l landmarks, appearance on HRCT and implications of the following structures will be discussed along with relevant pathological cases. 1. Canal for nerves: canal of cochlear nerve - canal

of superior vestibular nerve - canal of saccular nerve - canal of singular nerve - chorda tympani - inferior tympanic canaliculus - mastoid canaliculus - subarcuate canaliculus - groove for greater superficial petrosal nerve

2. Labyrinthine apparatus: vestibular aqueduct, cochlear aqueduct

3. Muscles: Stapedius, Tensor tympani4. Retrotympanic recess and other hidden spaces: Sinus

tympani, facial recess, lateral and posterior tympanic sinus, Prusaac's space, anterior epitympanic space.

5. Sutures - Intrinsic and extrinsic temporal bone sutures.

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SE 10 NR(HN)-04 New organ-based tube current modulation method to reduce the radiation dose during computed tomography of the head: comparison of image quality and radiation dose to the eyesSang-Wook Yoon1, Jung-Su Kim2 1CHA University, CHA Bundang Medical Center, 2Chungbuk Health & Science University, Korea. jansons@cha.ac.kr

PURPOSE: New organ-based tube current modulation (NOB-TCM) method was designed and developed with the intent to decrease tube current by 30% over a prescribed 90 radial arc across the anterior aspect of the radiosensitive organ, without increasing tube current in the remaining radial arc. In this study, we compared a reference scan without a dose reduction method and six other dosage-reducing scanning methods with regard to effects on dose, practicality, and image quality to determine the most effective method for reduce the radiation dose to the eyes during computed tomography (CT) examinations of the head.MATERIALS AND METHODS: We compared the radiation doses to the eyes and physical image quality (noise, signal-to-noise ratio [SNR], figure of merit [FOM]) in different regions of interest (ROI) for TCM and in-plane shield scans. Three types of TCM scans were performed: longitudinal TCM (auto mA setting), angular TCM (smart scan), and NOB-TCM (smart mA). A bismuth sheet, titanium sheet, and lead goggles were applied for the in-plane shield scan.RESULTS: Relative to the reference scan, the dose to the eye was reduced to 25.88% with NOB-TCM, 44.53% with lead goggles, 36.91% with a bismuth shield, and 9.01% with a titanium shield, respectively. Again, relative to the reference scan, the mean SNR decreased to 8.02% with NOB-TCM, 28.36% with lead goggles, and 32.95% with a bismuth shield. The SNR of the anterior ROI in a CT dose index (CTDI) image of a phantom decreased to 11.89% with NOB-TCM and 87.89% with a bismuth shield. The average FOM increased by 11.7% with longitudinal TCM and 13.39% with NOB-TCM, compared with the reference scan. However, decreases of 0.8%, 9.2%, and 3.6% were observed with angular TCM, a bismuth shield, and lead goggles, respectively.CONCLUSION: For CT imaging of the anterior brain region, NOB-TCM was more effective than in-plane shielding techniques in terms of radiation dose reduction to the eyes and image quality. NOB-TCM is a superior solution for facial bone scans because it could reduce radiation exposure without a significant loss in image quality.

SE 10 NR(HN)-05Assessment of the vidian canal in Indian population by high resolution multi-detector CT of base of skullKewal Mistry1, Parikshit Morey2, Pokhraj Suthar3, Rohit Bhoil4 1Department of Radiology, Synergy Institute of Medical Science, 2Dr Rajendra Prasad Government Medical College, 3Sterling Hospitals, 4Indira Gandhi Medical College, India. drkewalmd@gmail.com

PURPOSE: To assess the vidian (pterygoid) canal and its morphology in Indian population by high resolution multi-detector computed tomography (CT) of base of skull.MATERIALS AND METHODS: The anatomical data of vidian canal was generated by using non contrast enhanced high resolution multi-detector CT scans (section thickness = 0.8 mm) of 90 patients (40 males, 50 females) with ages of 18 to 80 years with mean age 40.01 ± 15.75 (mean ± SD) who underwent HRCT of temporal bone and base of skull for indications not related to vidian canal. All 180 vidian canals were assessed for type, length, internal diameters and dehiscence of walls on axial and coronal reformatted sections. Statistical analysis was performed using MS Excel.RESULTS: Out of the total examined 180 canals (including both sides), 29 (16.11%) were type I (protruding within the sphenoid sinus), 45 (25%) were type II (partially protruding into sphenoid sinus) and 106 (58.89%) canals were type III (completely embedded within body of sphenoid bone). The length of vidian canal varied from 9.5 mm to 24.2 mm. The mean length of vidian canal was 14.03 ± 2 mm on right side and 14.12 ± 2.17 mm on left side. The internal diameter (excluding bony walls) of vidian canal varied from 0.4 mm to 3.9 mm. The average internal diameter of vidian canal on right was 1.36 ± 0.50 mm and on left was 1.32 ± 0.44 mm. Out of 180 patients 8 patients showed superior dehiscence on both sides, 13 patients showed unilateral dehiscence on right and 9 on left side.CONCLUSION: Preoperative high resolution CT scan can accurately delineate the anatomical variations of the vidian canal including its type, length of projection into the sphenoid sinus and dehiscence of its bony walls.CLINICAL RELEVANCE/APPLICATION: The vidian canal is the conduit through the sphenoid bone through which vidian nerve and artery pass. It is an important landmark in various surgical approaches to the skull base. Knowledge of exact anatomy of the vidian canal can improve the results and decrease the complications of the endoscopic trans-sphenoidal and vidian neurectomy surgeries.

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SE 10 NR(HN)-06 Cervical lymph node imaging in head and neck cancersEugene Ng Ng Teng Fong General Hospital, Singapore. eugenengcw@gmail.com

OBJECTIVES: - Review the current diagnostic criteria used in

conventional imaging to diagnose metastases in cervical nodes by evaluating nodal size, shape, morphology, margins and distribution.

- To present the nodal site classification and recognize these sites in cross sectional imaging.

- To present pertinent staging features of the various head and neck cancers.

- Briefly discuss other imaging modalities used for nodal assessment such as Positron emission tomography- Computed tomography (PET-CT), diffusion weighted imaging (DWI) and CT perfusion.

BACKGROUND: An important prognostic factor in head and neck cancers is the presence or absence of neck nodes because it impacts staging and prognosis. The presence of metastases in a lymph node is reported to reduce the 5-years survival rate by about 50%. The appropriate diagnosis of the presence of metastatic node is crucial for the staging and management.IMAGING FINDINGS: Imaging can identify pathologic cervical adenopathy in a significant number of patients with head and neck cancer who have no palpable adenopathy on physical examination. Therefore it has become routine to perform ultrasound, CT or MRI as workup. We present a series of clinical encountered cases of abnormal cervical lymph nodes in various head and neck malignancies and highlighting their imaging features seen in the various imaging modalities.CONCLUSION: Imaging assessment of nodal disease can be challenging for radiologists because of multiple nodal sites and varying opinions on abnormal nodes. Detection of occult metastases has limitation

as micrometastases cannot be accurately depicted. However accuracy of assessment can improve with knowledge of criteria, nodal drainage pathways, common imaging pitfalls as well as high level of suspicion on the part of the radiologist.

SE 10 NR(HN)-07 Cervical vertebra X-ray changes of patients with blood supply deficiency encephalopathyTungalagtamir Khurelbaatar1, Badamsed Tserendorj2 1Monglian National University of Medical Sciences, 2Institute of Medical Sciences, Mongolia. tamiraa0329@yahoo.com

PURPOSE: To determine the relationship between blood supply deficiency encephalopathy stages and cervical vertebra X-ray changes of patients with loss of blood supply encephalopathy.MATERIALS AND METHODS: From 2014 to 2016, 87 patients with blood supply deficiency encephalopathy were taken X-ray images on anterior, posterior, lateral view and done functional tests (incline, recline, tilt to right and left) at X-ray room of the Department of Radiology of Third Central Hospital named after P.N. Shastin, Ulaanbaatar, Mongolia.RESULTS: According to relationship between cervical vertebra X-ray changes of patients with blood supply deficiency encephalopathy and the stages of blood supply deficiency encephalopathy, we have observed several findings below. At the 1st stage of blood supply deficiency encephalopathy revealed intravertebral osteochondrosis - 80%, uncovertebral arthrosis - 16%, herniated vertebral disc - 4.0%, kimmerle anomaly - 8%, C7 vertebral extraprocess - 4%, location change -76%. At the 2nd stage of blood supply deficit encephalopathy revealed intravertebral osteochondrosis - 77.8%, uncovertebral arthrosis - 40%, herniated vertebral disc -15.6%, atlanto-occipitalis dislocation - 4.4%, kimmerle anomaly - 6.7%, C7 vertebral extraprocess - 11.7%, location change - 86.7%. At the 3rd stage of blood supply deficiency encephalopathy revealed intravertebral osteochondrosis - 82.4%, uncovertebral arthrosis - 35.3%, C7 vertebral extraprocess - 5.9%, location change - 100%.CONLUSION: Cerv ical ver tebral changes are frequently diagnosed with X-ray and we can predict that these changes can cause blood supply deficiency encephalopathy.

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SE 10 NR(HN)-08 MR imaging findings for orbital apex syndromeHokyu Lee, Myeong Ju Koh Jeju National University Hospital, Korea. hoklee33@gmail.com

PURPOSE: Orbital apex syndrome is a rare condition characterized by visual loss from optic nerve neuropathy and ophthalmoplegia involving multiple cranial nerves. This may result from a variety of pathological process around optic canal and superior orbital fissure. The purpose of this exhibit is to review key concepts of orbital apex syndrome with emphasis on the relevant anatomy, pathophysiology, and MRI evaluation of the disease of the orbital apex.CONTENT ORGANIZATION: The orbital apex region consists of the optic nerve sheath complex, the conal, the intraconal, the extraconal spaces and the bony orbit.1. The optic nerve sheath complex consists of the optic

nerve and three layers of the meninges.2. The intraconal space lies within the muscle cone,

and contains orbital fat, the ophthalmic artery, cranial nerves III and VI, and the nasociliary nerve of V1.

3. The cone consists of the four recti muscles and their origin at the annulus of Zinn at the orbital apex.

4. The extraconal space and the bony orbit. The extraconal space is the space between the muscular cone and the bony orbit. It contains extraconal orbital fat.

5. The bony orbit at the apex contains the optic canal and the superior orbital fissure.

Orbital apex syndrome may result from a variety of pathological process around optic canal and superior orbital fissure. MR imaging for the orbit was performed using coronal and axial T1-, and T2-weighted imaging (WI)/contrast-enhanced T1-WI and FLAIR with fat suppression.SUMMARY: MRI is the important diagnostic tool for the evaluation of orbital apex lesions based on anatomic localizations: Coronal MR imaging is useful for localization of orbital apex lesions. Contrast enhanced-T1 WI and 2D FLAIR with fat suppression help to differentiate lesions of the optic nerve from lesions of optic nerve-sheath complex. In addition, diffusion weighted imaging is required to get additional information for characterization of pathologies. Categorization of the orbital apex lesions based on their anatomic locations helps to form a systematic and a simplified approach to the wide range of these lesions.

SE 10 NR(HN)-09 MR imaging features of minor salivary gland tumorsAmit Karandikar1, Siu Cheng Loke1, Julian Goh1, Tiong Yong Tan2 1Tan Tock Seng Hospital, 2Changi General Hospital, Singapore. amit_karandikar@ttsh.com.sg

PURPOSE: To retrospectively evaluate the MR imaging features of histologically proven minor salivary gland tumors (MSGTs).MATERIALS AND METHODS: A retrospective review of 29 histologically proven MSGTs was performed. All the patients underwent MRI study prior to surgery on superconducting magnets of 1.5T and 3T. MRI features of these tumors were evaluated.RESULTS: Of the surgically operated 29 patients, 12 were males and 17 were females. The commonest site of involvement was base of tongue (n = 7) and the commonest pathology was adenoid cystic carcinoma (n = 12). The imaging features compared were as follows- size, morphology, margins, surface, T2w signal, homogeneity and enhancement. All the MSGTs revealed smooth surface, well-defined margins and polypoidal appearance (100% sensitivity, 100% PPV). T2w hyperintensity (ranged from intense to intermediate hyperintensity) and enhancement results were variable and inconsistent. However, our study revealed that at all the tumors larger than 3.5 cm had a heterogeneous appearance with internal cystic foci.DISCUSSION: MSGTs are less common as compared to squamous cell cancer (SCC) or lymphoma seen more frequently in head and neck region. Our study revealed that all the MSGTs had smooth surface, well-defined margins and polypoidal appearance (100% sensitivity, 100% PPV). We also found that MSGTs larger than 3.5 cm showed a heterogeneous appearance with internal cystic foci. We feel that these signs can aid differentiating MSGTs from SCC and lymphoma. SCCs are locally infiltrative tumors with ill-defined margins. Smooth, well-defined margins with a polypoidal appearance in MSGTs can help distinguish them from SCC. Lymphomas present as intermediate T2w hyperintense masses with well-defined margins and a polypoidal or a lobulated appearance and hence may closely resemble MSGTs. But primary lymphoma tumoral masses generally are homogenous and as per our study, all large (more than 3.5 cm) MSGTs revealed heterogeneous appearance with internal cystic foci. This finding if present in larger tumors may help distinguishing MSGTs from lymphomas. Our study did not reveal any specific distinguishing feature in MSGTs on T2w or post contrast study. However intense T2w hyperintensity with intense enhancement, if present, can point to a diagnosis of MSGTs in contrast to lymphoma

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or a SCC which show intermediate T2w hyperintensity.

SE 10 NR(HN)-10Value of using contrast-enhanced magnetic resonance imaging for the evaluation of the short-term effects of radiotherapy for nasopharyngeal cancerLin Chen, Gen Yan Affiliated Hospital, Jiangnan University, China. gyan@stu.edu.cn

PURPOSE: To investigate the value of using contrast-enhanced magnetic resonance imaging (MRI) for efficient evaluation before and after radical radiotherapy for nasopharyngeal cancer, and to assess whether the use of visual partitioning analysis for tracking and observing nasopharyngeal cancer staging is sensitive to radiotherapy.MATERIALS AND METHODS: In total, 50 patients who were preliminarily diagnosed with nasopharyngeal cancer through pathological examinations were retrospectively analyzed, including 9 cases with stage T2, 29 cases with T3, and 12 cases with T4. All cases underwent short-term radiotherapy; T1 weighted imaging, T2 weighted imaging, and contrast-enhanced MRI were performed before and after radiotherapy. Visual partitioning analysis was used to comparatively measure the variations in morphology and range of foci, as well as the involvement of surrounding tissues. All the above mentioned data were statistically analyzed using independent sample t-tests.RESULTS: Compared to the conditions before radiotherapy, the tumor foci of 9 cases with parapharyngeal space and/or oropharynx involvement, 29 cases with skull base and/or medial pterygoid involvement, and 7 cases with cranial nerve and/or cavernous sinus and/or paranasal sinus and/or lateral pterygoid involvement showed significant shrinkage or reduction in the size of their cervical lymph nodes, along with non-apparent enhancement or no trend in enhancement (p < 0.05). However, among 5 T4 cases, the tumor size non-significantly changed in 4 cases and increased in 1 case (p < 0.05); moreover, the intensities of the standardized enhancement of foci did not significantly change.CONCLUSION: The changes in nasopharyngeal cancer before and after radiotherapy can be sensitively determined through contrast-enhanced MRI, which may thus have good clinical applicability in the effective evaluation of nasopharyngeal cancer. Moreover, the efficacy of radiotherapy for nasopharyngeal cancer may be associated with the pathological staging.

SE 10 NR(HN)-11Nasal cavity neoplasm and mimics: a pictorial reviewYoo Kyung Nau1, Seul Kee Kim1, Woong Yoon2, Byung Hyun Baek2, Yun Young Lee1 1Chonnam National University Hwasun Hospital, 2Chonnam National University Hospital, Korea. kimsk.rad@gmail.com

PURPOSE: A wide variety of tumors may arise from the nasal cavity, commonly with overlapping clinical presentations. This exhibit will review imaging findings of nasal cavity neoplasms and mimics.CONTENT ORGANIZATION: We retrospectively review of clinical and imaging findings in patient with nasal cavity lesion. A wide variety of nasal cavity tumors are described, including, squamous cell carcinoma, undifferentiated carcinoma, melanoma, lymphoma, plasmacytoma, chondrosarcoma, juvenile angiofibroma, hemangioma, solitary fibrous tumor, esthesioneuroblastoma and inverted papilloma. Non-neoplastic mimics such as, polyposis, allergic fungal sinusitis with sinonasal polyposis, encephalocele, and nasal glioma also are reviewed.CONCLUSION: Imaging plays an important role in the management of patients with lesions of nasal cavity, and it is essential that the radiologist knows relevant anatomy and key differentiating imaging features that allow an appropriate differential diagnosis.

SE 10 NR(HN)-12Thyroglossal duct cyst: imaging characteristics and clinical correlationSeongsu Kang, In Ho Lee, Da Mi Kim, Chang June Song Chungnam National University Hospital, Korea. leeinho1974@cnuh.co.kr

PURPOSE: Thyroglossal duct cysts (TGDC) are most common congenital neck masses. Most patients present with painless midline neck mass, but sometimes can be painful. Although the incidence is very rare, less than 1%, thyroid carcinoma can arise from TGDC. The purpose of this study is to evaluate the imaging findings of TGDC on CT.MATERIALS AND METHODS: We retrospectively reviewed the imaging findings and medical records of 71 patients (M:F = 34:37; age range, 3-70 years; mean age, 36.4 ± 17.2 years; median age, 34 years) with pathologically proven TGDC between January 2009 and August 2014. We evaluated the lesion location based on hyoid bone, size, presence of calcification, enhancement pattern on CT scans. We also reviewed clinical findings

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including presenting symptoms, treatment, and recurrence.RESULTS: Most patients present with painless midline neck mass. Of total 71 TGDCs, 60 cases were found in adult patients (more than 18 years old) while only 11 cases were found in pediatric patients. Sixty nine of 71 cases (97%) were located in the infrahyoid neck with midline location (n = 45/69, 65%) and left or right location (n = 24/69, 35%) while only two cases were located at the level of hyoid bone. 54 cases showed well circumscribed non-enhancing cystic lesion while 15 cases showed well circumscribed cystic lesion with mildly peripheral or septal enhancement. The other 2 cases, which are TGDC with coexistence of papillary thyroid carcinoma, had enhancing solid component as well as non-enhancing cystic component. The sizes in all cases showed mean and standard deviation of 2.4 cm and 0.8 cm (range, 1.0-5.2 cm). There were three cases with curvilinear or tiny calcifications in the peripheral portion of TGDC. There were 21 cases with septation. All patients underwent Sistrunk operation and there was no recurrence.CONCLUSION: Most TDGC showed well circumscribed non-enhancing or peripheral enhancing cystic lesions in the midline of the infrahyoid neck. However, although the incidence of solid enhancing component and calcification is very low, coexistence of papillary thyroid carcinoma and calcification should be considered.

SE 10 NR(HN)-13 “Papilledema”: what the radiologist needs to know?Gun Su Kim1, 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: Papilledema is the term used to describe optic disc swelling associated with increased intracranial pressure (ICP). Cause of raised ICP can be any space occupying lesions like hematoma, abscess, neoplasm, infarction, cerebral edema, and pseudotumor cerebri. When papilledema is found on fundoscopy, further evaluation is warranted as vision loss can occur if the underlying cause of raised ICP not removed. Non-invasive diagnosis is possible by using high-resolution MR imaging, with a variety of findings occurring in the setting of papilledema. The aim of this educational exhibition is to review pathologic mechanism and diagnostic key MR imaging findings of papilledema.CONTENT ORGANIZATION:1. Introduction: Pathologic mechanism and clinical

implication of papilledema2. Review of the radiologic key imaging findings of

papilledema1) Widening of optic nerve sheath2) Flattening of the posterior sclera3) Protrusion of the optic disc4) Tortuosity of the optic nerve

3. Etiology of increased intracranial pressure: differential diagnosis1) Increased blood volume: venous thrombosis,

hemorrhagic stroke2) Increased brain volume: neoplasm, cerebral

edema3) Increased CSF volume: increased production,

decreased absorption, obstruction to CSF flow4) Idiopathic intracranial hypertension (pseudotumor

cerebri)4. Case-based diagnostic approach in patient with

papilledema5. SummaryCONCLUSION: Papilledema is a warning sign for elevated ICP and potential vision loss in a variety of clinical settings. The knowledge of imaging findings and pathomechanism of papilledema plays an important role in its detection and prompt management of the patient.

SE 10 NR(HN)-14 Small field-of-view MR imaging evaluation of laryngeal and hypopharyngeal neoplasmsSiu Cheng Loke Tan Tock Seng Hospital, Singapore. siuloke@hotmail.com

Assessment of submucosal extent of laryngeal and hypopharyngeal neoplasms requires the use of imaging. The mainstay of imaging in this case has traditionally employed CT, with its benefits of fast acquisition, higher resolution (thin slices) and lower cost. However CT has poor soft tissue contrast resolution, hampering accurate assessment of soft tissue structure involvement (e.g., laryngeal cartilage); CT assessment of post-treatment changes is also challenging.Clearer depiction of primary tumor and local involvement is required in view of advances in treatment, not only for more accurate preoperative staging and prognostication but also for patient selection.CT has high specificity but low sensitivity and mean accuracy of 75-80%, which may result in laryngectomy in cases where organ preservation surgery could have been performed.MRI has been shown to be superior to CT in evaluation of laryngeal cancer.Standard large field-of-view (FOV) MR of the larynx has better soft tissue resolution than CT, but has poor depiction of subtle changes. Small FOV MR allows for far superior depiction of disease extent and involvement.

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Using imaging examples we discuss the advantages of small FOV MR imaging in accurate assessment of laryngeal and hypopharyngeal neoplasms, particularly in T (tumor) staging.

SE 10 NR(HN)-15 Preoperative CT localization of the anterior ethmoidal artery before endoscopic sinus surgeryRajiv Raju1, Caroline Hudson1, Nikhil Bhatt1, Silpa Raju2 1University of Illinois at Chicago, College of Medicine, 2Dartmouth College, USA.rraju4@uic.edu

CONTENT ORGANIZATION: Improve awareness of the surgical significance of the anterior ethmoidal artery (AEA) among radiologists. When the AEA lies below the skull base it is at risk of injury during endoscopic sinus surgery. If the AEA is injured during sinus surgery, it may retract into the orbit and result in orbital hematoma which in turn can potentially cause blindness. When the AEA is identified preoperatively on CT scans, the risk of injury to the AEA can be decreased.Review the relevant anatomy of the AEA which is a branch of the ophthalmic artery and extends out of the orbit via the AEA foramen in the medial wall of the orbit. After exiting the AEA foramen it may pass through the ethmoid roof at the skull base or through the ethmoid air cells below the skull base. The AEA canal in the ethmoid region is more likely to be below the skull base when Supraorbital Ethmoid Cells (SEOC) are present. SOECs are quite common in western populations.Illustrate how the AEA can be identified using high resolution modern scanners and interactive multiplane reformatting on workstations. The AEA foramen can be identified on coronal CT images as a bony outpouching along the medial wall of the orbit near the inferior margin of the superior oblique muscle. The coronal image that contains the AEA is commonly near the posterior margin of the globe. Once the AEA foramen is identified, interactive cross referencing can be used on the imaging workstation to identify the AEA canal in the ethmoid region in all planes. The CT imaging signs which can be used identify the AEA will be illustrated using CT image examples. Different types of SEOC and their significance to the position of the AEA relative to the skull base will be illustrated with CT image examples.SUMMARY: After viewing the exhibit, the radiologist should understand the surgical significance of the AEA and be able to identify the AEA foramen and AEA canal on sinus CT studies. They should also be able to determine when the AEA is at increased risk of injury when SOECs are present.

SE 10 NR(HN)-16Buttresses of the face: structural integrity and failureJayendra Alampally, Sundeep Malla, Atin Kumar, Shivanand Gamanagatti All India Institutes of Medical Sciences, New Delhi, India. allampallyjayendra@gmail.com

TEACHING POINT: The relative complexity of the face, presence of vital structures and psychological impact of disfigurement makes understanding of facial fractures important. Motor vehicle accidents, assaults and falls are the common modes of facial injury. The buttress concept is intended for simple but better understanding of facial structures and in aiding surgical management. The exhibit intends to demonstrate the buttress concept and its application in the evaluation of facial fractures.CONTENT ORGANIZATION:1. Introduction: facial buttresses2. Imaging modalities: role of radiography, USG, CT and

MRI3. Facial fractures: types, complications and mode of

management1) Nasal bone2) Nasoorbitoethmoid (NOE)3) Zygomaticomaxillary complex4) Orbital5) Le Fort6) Mandibular

4. Role of digital subtraction angiography

Fig. 1. 40 year male who underwent road traffic accident. Volume rendered CT image showing bilateral Le Fort type II and III fractures.

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SE 10 NR(HN)-17Sinonasal vascular mass lesions: a report of two rare differential diagnosis on MR imaging with clinicohistopathologic correlationChristina Paola Pacpaco1, Mercedes Dizon2, Roy Allan Dominique Torcuator2, Rolando Lopez2, Marie Christine Bernardo2, Manuel Mariano2 1St. Luke's Medical Center - Global City, 2St. Luke's Medical Center, Philippines. pao.pacpaco.md@gmail.com

We present two rare cases of sinonasal vascular mass lesions. First case is intravascular papillary endothelial hyperplasia (IPEH), also known as Masson’s tumor, which is a benign non-neoplastic intravascular lesion comprising of reactive proliferative endothelial cells often organizing in a thrombosed vessel. Second case is glomangiopericytoma, also known as sinonasal type hemangiopericytoma, which is a borderline low malignancy neoplasm of perivascular myoid phenotype. Vascular mass lesions are rarely seen in the sinonasal region. The clinical picture of IPEH and glomangiopericytoma are non-specific and their MR imaging features are almost similar, relying on histopathology for diagnosis. Here we review available literature and discuss two possible differential diagnosis for sinonasal vascular mass lesion on MR imaging, with clinicohistopathologic correlation.

Figure 1. Sagittal MR images of intravascular papillary endothelial hyperplasia. The lesion expanding the sphenoid sinus appears lobulated and hyperintense on the T2-weighted image (A). On the subsequent pre- and post-contrast T1C-weighted image, the T1 isointense lesion (B) shows solid and almost homogeneous enhancement (C).

Figure 2. Sagittal MR images of glomangiopericytoma. The well-circumscribed lobulated lesion involving the sphenoid and posterior ethmoid sinuses demonstrates T2-weighted hyperintense signal (A). There is avid enhancement of the lesion on post- contrast T1-weighted image, reflecting its vascular nature (B).

SE 10 NR(HN)-18 Understanding for advanced dual energy CT techniques in the head and neck tumor imaging: from basic technical principle to the clinical application Young Hen Lee Korea University Ansan Hospital, Korea. younghen@empal.com

Dual-energy computed tomography (DECT), a breakthrough of CT technology, has been increasingly applied in the head and neck tumors as other body regions, Basically, DECT has the capability of material differentiation by simultaneous or near-simultaneous acquisitions of two CT datasets with different X-ray spectra. To provide clinically relevant information, dual-energy datasets are post-processed with different algorithms and applications to generate images with material- or energy-specific information (e.g., blended images, virtual non-contrast-enhanced images and, virtual monochromatic images). Early results are promising, and further research is encouraged.To explain the role of DECT in head and neck tumor, this exhibit will begin with a brief overview of different approaches to DECT scanning and address basic issues related to image quality and acquisition dose. This will be followed by a review of the use of different post-processing techniques for improving head and neck cancer visualization, such as tumor extent, and invasion of critical structures. The article will conclude with a brief review of other emerging applications of DECT for evaluation of different head and neck cancers and advanced tumor analysis.

598 KCR 2016

Neuroradiology (H

N)

SE 10 NR(HN)-19Dynamic susceptibility contrast perfusion MR imaging in the evaluation of parotid gland tumorsShin Young Park, Jeong Myeong Kim, Hak Jin Kim Pusan National University Hospital, Korea. psy@pusan.ac.kr

To determine the efficacy of dynamic susceptibility contrast perfusion MR imaging (DSC-MR) against conventional and diffusion-weighted (DW) MR imaging for differentiating parotid gland tumors.We included 7 malignant parotid tumors, 17 pleomorphic adenomas, 4 Warthin’s tumors, 2 schwannomas, and 3 benign parotid lesions (oncocytoma, atypical lymphoid hyperplasia, and florid reactive follicular hyperplasia). Only tumors lager than 1.0 cm were included in our study. 25 parotid tumors underwent surgical resection, 8 underwent ultrasonography-guided core needle biopsy. T1-weighted, T2-weighted, DW, DSC, and contrast-enhanced T1-weighted MR imaging were performed in all patients with parotid gland tumors. The signal intensity time curve of the tumor was obtained. Dynamic susceptibility contrast percentage (DSC%) was calculated and correlated with pathological findings. The apparent diffusion coefficient (ADC) value of the solid component was measured on DW MR images. Tumor to parotid gland signal intensity ratios (SIRs) of solid components were correlated with these pathologies.DSC% was significantly higher in malignant parotid gland tumors (59.09%) than benign tumors (36.88%) (p = 0.018). DSC% cutoff value was 49.30% for distinguishing between benign and malignant parotid gland tumors (sensitivity, specificity, and accuracy of DSC% threshold of over 49.30% were 71.4%, 68.0%, and 68.75%, respectively). ADC value and SIRs on T2-weighted images were higher in benign parotid gland tumors, especially pleomorphic adenomas than in Warthin’s tumors (p < 0.01) and malignant tumors (p < 0.01). ADC cutoff value was 0.876 for distinguishing between benign and malignant parotid gland tumors (sensitivity, specificity, and accuracy of ADC threshold of over 0.876 were 85.71%, 84.62%, and 84.85%, respectively).Dynamic susceptibility contrast perfusion MR imaging with SIR measurements and ADC value can play a role in differentiation between pleomorphic adenomas and other parotid gland tumors.

SE 10 NR(HN)-20Common orbital diseases in adults: diagnosis with CT and MR imagingSoo yeon Jeong, Se jeong Jeon, See sung Choi Wonkwang University Hospital, Korea.medicalq@hanmail.net

PURPOSE: The orbit is the bony socket which contains the globe, muscles, lacrimal gland, nerves, vessels, and fat. Any disease conditions can affect any of these structures and can cause disease in orbit. Knowledges of the imaging features of various orbital disease conditions - infections, inflammations, vascular abnormalities, trauma, and tumor - may help distinguish among lesions that have overlapping clinical presentations and help make prompt and accurate diagnosis. This review focuses on some of the common orbital conditions. Key imaging features are illustrated.MATERIALS AND METHODS: We retrospectively identified the patients who performed orbital imaging including CT and MR imaging in our institution over the past 10 years.RESULTS: Disease entities include; 1) Trauma 2) Infection or Inflammation 3) Vascular diseases 4) Tumorous conditions including benign and malignancy.CONCLUSION: CT is the 1st line modality for radiologic evaluation of the orbit and MR imaging is a useful 2ndary modality which has excellent tissue contrast resolution. Understanding the imaging findings of common diseases of the orbit helps avoid unnecessary diagnostic work-up and treatment.

SE 10 NR(HN)-21CT imaging characteristics of lobular capillary hemangioma in the nasal cavity in comparison with cavernous or capillary hemangioma: clinical correlationIn Ho Lee Chungnam National University Hospital, Korea. leeinho1974@hanmail.net

PURPOSE: There is substantial overlap in the imaging characteristics between lobular capillary hemangioma and cavernous or capillary hemangioma in the nasal cavity. The purpose of this study was to describe the imaging characteristics of lobular capillary hemangioma, previously known as pyogenic granuloma, in the nasal cavity and compare those with cavernous or capillary hemangioma in the nasal cavity.MATERIALS AND METHODS: We retrospectively reviewed ten patients with lobular capillary hemangioma in the nasal cavity, four patients with cavernous hemangioma, and one patient with capillary hemangioma

Scientific Exhibitions 599

Neuroradiology (N

I)

between January 2010 and March 2016.We evaluated the imaging findings including lesion location, attenuation on pre- and post-contrast CT scan, adjacent bony change, intralesional calcification and enhancement pattern. We also evaluated the clinical findings such as presenting symptoms.RESULTS: Most patients presented with epistaxis (lobular capillary hemangioma: 9 patients, cavernous hemangioma: 2 patients, capillary hemangioma: 1 patient). Remaining patients presented with foul odor (1, lobular capillary hemangioma) and rhinorrhea (2, cavernous hemangioma). Most lesions, regardless of type, were located in the turbinate or nasal septum. Except one patient (lobular capillary hemangioma) without contrast study, 9 patients (lobular capillary hemangioma: 6, cavernous: 2, capillary: 1) showed strong enhancement while 4 patients showed mild or poor enhancement. However, lobular capillary or capillary hemangioma showed homogeneous enhancement while cavernous hemangioma showed heterogeneous enhancement. Intralesional calcification or adjacent bony changes were not noted in any cases.CONCLUSION: Most hemangiomas in the nasal cavity present with well circumscribed small mass with epistaxis. Although there were no significant differences of imaging findings between lobular capillary, cavernous or capillary, enhancement pattern, that is lobular capillary hemangioma with homogeneously strong enhancement in contrast to cavernous hemangioma with heterogeneously strong enhancement, may be helpful for differential diagnosis.

Neurointervention

SE 11 NR(NI)-01 Citation classics in neuro-interventional research: a bibliometric analysis of the 100 most-cited articlesEun Soo Kim1, Dae Young Yoon2, Hye Jeong Kim3, Hong Jun Jeon4, Jong Young Lee4 1Hallym University Sacred Heart Hospital, 2Kangdong Sacred Heart Hospital, 3Kangnam Sacred Heart Hospital, Hallym University, 4Kangdong Sacred Heart Hospital, Hallym University, Korea. evee0914@chollian.net

PURPOSE: The number of citations that an article has received can be used to evaluate its impact on the scientific community. This article aimed to identify the 100 most-cited articles in the field of neuro-intervention and to analyze their characteristics.MATERIALS AND METHODS: We selected the 669 journals that were considered journals potentially

publishing neuro-intervention articles based on the database of Journal Citation Reports. Using the Web of Science citation search tool, we identified the 100 most-cited articles relevant to neuro-intervention within selected journals. Each articles were evaluated for several characteristics including publication year, journal, journal category, impact factor, number of citations, number of citations per year, authorship, department, institution, country, type of article, and topic.RESULTS: The number of citations for the top 100 articles ranged from 1,912 to 170 (mean, 363.4) and citations per year ranged from 271.0 to 4.1 (mean, 40.0). The majority of articles were published in clinical neurology journals (63%), published in 2000-2009 (39%), originated in the United States (45%), were original articles (95%), and dealt with endovascular treatment of cerebral aneurysm (42%). Department of Radiology, University of California School of Medicine (n = 12) was the leading institution and Viñuela F (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 neuro-intervention and provides a historical perspective on the scientific progress in this field.

SE 11 NR(NI)-02 Intentional stent retriever detachment during thrombectomy in patients with acute ischemic stroke: case reportSoo Mee Lim, Tae jin Song, Na-Young Shin Ewha Womans University Mokdong Hospital, Korea. soomee@ewha.ac.kr

Mechanical thrombectomy using retrievable stents or stent retriever devices has become the mainstay of intra-arterial therapy for acute ischemic stroke. We experienced 4 cases of intentional detachment of stent retriever during thrombectomy in patients with acute ischemic stroke. In these cases, in spite of 3 or more times of trial of thrombectomy procedure using retrievable stent, recanalization of occluded large artery was not performed, but stenting in this vessel could preserve arterial patency. Among them one was in vertebral artery and others were in M1 segment. Follow up CT head angiography showed patency of stented vessel in only one case. And mRS was 2 in 2 patients, 1 and 6 in the rest patients at the time of discharge. Clinically neurologic symptoms were improved in 3 patients. We can suspect that the more time opening of involved arteries can improve brain perfusion.

Scientific Exhibitions 603

Neuroradiology

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