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Neuroradiology/Head and Neck

Krishnan A.¹; Vora M.; Aygun N.²; 1. Neuroradiology and Diagnostic Radiology, William Beaumont Hospital, Royal Oak, MI; 2. Neuroradiology, The Johns Hopkins Hospital, Baltimore, MD.

Address correspondence to A. Krishnan (akrishnan{at}beaumont.edu)

Background: The brainstem is an extremely eloquent part of the nervous system that is challenging to image from its relatively small size and location. Despite advances in CT software (including beam hardening correction algorithms), it is primarily evaluated by MRI. Even the latter is limited from artifacts such as in FLAIR sequences as well as artifacts in gradient sequences from susceptibility. Yet, the importance of making a correct diagnosis is paramount here as biopsies can cause serious damage. In certain diagnoses such as infiltrating gliomas, a decision whether to provide definitive care or pursue palliative measures is based heavily on the imaging result. Thus the radiologist is obligated to make a critical assessment of the findings by using every possible imaging tool and understanding the conditions that are `touch me nots' when conferring with the neurosurgeon.

Key Issues: Many non-neoplastic conditions can mimic neoplasms both clinically and radiologically. Careful review of these cases however shows additional findings that would prompt a different diagnosis. This would include using the location, enhancement properties, behavior with diffusion sequences and spectroscopy to postulate a cause for the findings rather than providing a long differential of neoplastic and benign conditions. Some of the included conditions are Acute disseminated encephalomyelitis (ADEM), other demyelinating processes, infectious diseases, HIV, Langerhans Cell Histiocytosis, metabolic conditions including Wernicke's encephalopathy, maple syrup disease, vascular abnormalities including malformations, cavernomas, and infarcts, unusual appearances of hemorrhage, sickle cell encephalopathy and some unusual causes.

Format: Combination of didactic review on various conditions, taking into account location and pathology, with interspersed interaction to provide the viewer the opportunity to learn and play the role of the consultant when faced with a difficult case.

Teaching Points: 1. Describe and display the peculiar imaging features of non-neoplastic conditions of the brain-stem permitting a definitive diagnosis in some and a meaningful differential in others. 2. Understanding the tendency for certain conditions to involve particular areas of the posterior fossa. 3. Utilizing spectroscopy and other modern tools in the posterior fossa with realization of their limitations and artifacts.

E279. Imaging Characteristics of Selected Neurodegenerative Diseases

Frederick J.A.; Maldjian J.A.; Burdette J.H.; Department of Radiology, Wake Forest University School of Medicine, Winston-Salem, NC.

Address correspondence to J.A. Frederick (jfrederi{at}wfubmc.edu)

Background: Neurodegenerative diseases affect an estimated 22 million individuals worldwide. In the United States, nearly 5.5 million people have been afflicted with Alzheimer's, Parkinson's, Huntington's, or Pick's disease at an estimated annual healthcare cost of over $65 billion. These numbers are projected to increase as our population ages.

Key Issues: Alzheimer's disease demonstrates medial temporal lobe atrophy on thin-section coronal T1-weighted MRI. FDG PET reveals temporoparietal metabolic deficits, and SPECT imaging exhibits bilateral temporoparietal hypoperfusion and decreased uptake in the medial temporal lobes and cingulate regions. Parkinson's disease demonstrates decreased width of the pars compacta on MRI. PET imaging with FDOPA displays decreased uptake in the posterior striatum, particularly in the putamen. FDG PET studies show diffuse cortical hypometabolism predominately in the parietotemporal cortex. Huntington's disease characteristically exhibits caudate atrophy on imaging. CT and T1-weighted MRI demonstrate a decrease in the convexity of the caudate heads bilaterally and/or an increase in the relative volume of the lateral ventricles. Putaminal atrophy may also be evident. On T2-weighted MRI, there may be increased signal intensity in the caudate and putamen and decreased signal intensity in the globus pallidus. Pick's disease appears as prominent atrophy of the temporal and/or frontal lobes on CT. Sulcal prominence, widening of the Sylvian fissure with atrophy of the insula, inferior frontal and superior temporal lobes, and enlargement of the frontal or temporal horns of the lateral ventricles is evident on MRI. Hypoperfusion defects in the ventromedial frontal region and temporal lobes are demonstrated on SPECT cerebral perfusion images.

Format: Didactic poster presentation with selected imaging demonstrating key findings.

Teaching Points: 1. Neurodegenerative diseases are becoming increasingly common. There are specific radiologic findings that should cue the radiologist to include them in their differential diagnosis of patients with mental status changes in the appropriate clinical setting. 2. Radiologists can aid primary care physicians and specialists in the diagnosis and management of patients afflicted by these diseases.

E280. Diffusion-weighted MRI of Creutzfeldt-Jakob disease: Is It Really A Specific Finding Even in Its Hyper-acute Phase?

Ukisu R.; Inaba M.; Usui N.; Tanaka E.; Kurashita Y.; Kushihashi T.; Radiology, Showa University Northern Yokohama Hospital, Yokohama, Japan.

Address correspondence to R. Ukisu (ukisu{at}med.showa-u.ac.jp)

Background: The object of this exhibit is to evaluate the clinical usefulness and pitfalls of diffusion-weighted MRI (DWI) findings of Creutzfeldt-Jakob disease (CJD) in hyper-acute phase, focusing on the distribution of abnormal high signal intensities.

Key Issues: We reviewed ten cases of CJD in which DWI was performed before the onset of the characteristic clinical findings of periodic synchronous discharges on electroencephalograms and myoclonus. All had progressive dementia and expired within two years of the onset of the symptoms. Nine cases were sporadic CJD, and one case was iatrogenic. Four cases were diagnosed as definite CJD at autopsy and the others as probable CJD based on the clinical criteria. We also compared the sensitivities of the positive results of each MR sequences, and 14-3-3 protein test in cerebrospinal fluid which included in the WHO CJD diagnostic criteria. DWI revealed abnormal high signal intensities in the cortex which unrelated to arterial circulation inall patients. Abnormal signals were seen in the caudate nucleus in six cases, in the putamen in four, and thalamus in one. DWI is extremely useful in detection of CJD, however, in its hyper-acute phase, abnormal high signal intensities may restrict in cerebral cortex. In this setting, differentiation from venous hypertensive encephalopathy, chronic herpes encephalitis, and MELAS may become very important, because they also present with progressive dementia and abnormal cortical diffusion-weighted imaging signals. Comparing with other MR sequences becomes essential.

Format: This exhibit format will consist of a didactic review of the cases, and emphasize the importance of differential diagnosis on diffusion-weighted imaging of CJD in its hyper-acute phase.

Teaching Points: The teaching points of this exhibit is: (1) to recognize characteristics and pitfalls of various DWI findings of CJD in its hyper-acute phase, (2) to offer clues to their appropriate recognition to make a precise diagnosis, and aids to prevent human-to-human transmission, and (3) to learn how to differentiate CJD from other curable dementia.

E281. Brain Imaging in Susac's Syndrome

Saenz R.C.^1,2; Gean A.M.^1,2; Susac J.O.^3; 1. Radiology, San Francisco General Hospital, San Francisco, CA; 2. Radiology, University of California San Francisco, San Francisco, CA; 3. Neurology, Neurology & Neurosurgery Associates, Winter Haven, FL.

Address correspondence to R.C. Saenz (dr.rocky{at}gmail.com)

Background: Susac's syndrome is an uncommon neurological disorder described in 1979 by John Susac. The syndrome is an autoimmune endotheliopathy, affecting pre-capillary arterioles. The entity classically presents with a clinical triad of encephalopathy, hearing loss, and visual changes. It has recently been shown that certain MRI findings can be suggestive of the diagnosis. This disorder is frequently misdiagnosed as multiple sclerosis because of the involvement of the corpus callosum and the predilection for younger adults. The correct diagnosis aids the clinician in providing the optimal patient management.

Key Issues: The purpose of this educational exhibit is to review the history, clinical findings, pathology, and key imaging findings of Susac's Syndrome. We will also review the differential diagnosis of these radiological findings and also relevance of this under-diagnosed entity. We will present the imaging findings with MRI using 1.5 Tesla (T1, T2, Diffusion, FLAIR and Post Gadolinium sequences).

Format: This will be a didactic, power-point presentation.

Teaching Points: The Educational Objectives include: 1. Describe the relevant clinical and pathological features of Susac's Syndrome. 2. Recognize the radiological characteristics of Susac's Syndrome 3. Provide critical information to formulate an appropriate differential diagnosis.

E282. Pediatric Seizure Imaging

Tepe M.S.; Sze R.W.; Radiology, Seattle Children's Hospital, University of Washington, Seattle, WA.

Address correspondence to M.S. Tepe (mtepe{at}u.washington.edu)

Background: The incidence of seizure in the pediatric population in the United States is 0.5-1%. Fifteen to 30% of these patients have disease refractory to medical therapy and may need surgery. Computed tomography (CT) and magnetic resonance (MR) imaging are established technologies for location and characterization of epileptogenic origin, functional evaluation, prognosis and follow up after either medical or surgical treatment. Not all causes of seizure require imaging; febrile convulsions, hypoxic, metabolic, hypoglycemic and electrolyte imbalance are common causes of seizure needing treatment of underlying causes rather than imaging.

Key Issues: A broad spectrum of abnormal CT and MR images from pediatric patients with seizures are presented with discussion on characteristic diagnostic features. Categories include mesial temporal sclerosis; gray matter migrational errors (subependymal, band, and subcortical heterotopias and pachgyria); developmental malformations (schizencephaly, Taylor`s focal cortical dysplasia, Tuberous sclerosis); neoplasms (hypothalamic hamartoma, ganglioglioma, PNET); vascular malformation (cavernous malformation); infections (neurocycticercosis); idiopathic (Rasmussen encephalitis), and dual findings.

Format: Interactive tutorial presenting imaging studies followed by discussion of key imaging findings, diagnostic considerations, and optimal imaging techniques.

Teaching Points: Seizure is a common indication for pediatric neuro imaging. Abnormal findings can be extremely subtle. Optimal imaging technique and detailed knowledge of the spectrum of abnormalities causing seizures in children is critical. MR is the imaging modality of choice for seizure evaluation and very sensitive for detecting areas of cortical dysplasia or ectopic gray matter. Calcification is better evaluated by CT. Administration of gadolinium is usually not necessary. Close clinical correlation, a detailed patient history, an optimized MRI protocol, and careful head positioning within the coil are important features of seizure evaluation/imaging.

E283. Craniosynostosis-An Interactive 3-Dimensional Review

Khatri G.^.; Newatia A.; Johnson A.A.; Radiology, Long Island Jewish Medical Center, New Hyde Park, NY.

Address correspondence to G. Khatri (gkhatri{at}gmail.com)

Background: Craniosynostosis is a pathologic condition that results from the premature closure of one or more cranial sutures. The condition occurs in about 1 in 2,000 live births and may present as a solitary abnormality or with other congenital defects. It is classified based on the suture that is affected. The calvarium may take on a distinct shape associated with synostosis of that particular suture. Radiographic evaluation is generally pursued following clinical detection of abnormal calvarial configuration. Early diagnosis and characterization of the condition using three dimensional analysis aid in more favorable outcome post-surgery.

Key Issues: Primary radiologic signs of craniosynostosis include narrowing, indistinctness, or bony bridging along the suture. Occasionally, these changes may occur over a very short segment of the suture, or may be less obvious such as in cases of fibrous union. In such instances, radiological manifestations may be limited to secondary signs such as change in calvarial shape, alteration in shape and timing of closure of the fontanelles, and facial anomalies. Radiographic diagnosis is based on the relationship between the sutures and cranial shape. The normal pattern of cranial suture fusion and findings associated with synostoses of the sagittal, coronal, metopic, and lambdoid sutures are described using three dimensional reconstructions of axial CT scans. Using surface rendering algorithms, the actual appearance of the patient's head is displayed, and the characteristic cranial shapes associated with the various craniosynostoses including dolichocephaly, trigonocephaly, and plagiocephaly are shown.

Format: The exhibit will provide an interactive review of craniosynostosis, its classification, associated terminology, and skull abnormalities. Participants will be able to navigate through a series of images and clips portraying the radiologic findings related to sagittal, coronal, metopic, and lambdoid synostoses in 360 degrees. Surface rendering three dimensional algorithms will be used to also demonstrate the actual appearance of the patient's heads. The presentation will be organized based on the different types of craniosynostoses.

Teaching Points: The presentation will review craniosynostosis, its classification, epidemiology and pathophysiology. Viewers will be able to discern the radiologic features and skull shapes associated with the various synostoses, and gain an insight into associated complications, syndromes and management of craniosynostosis.

E284. Dural Sinus Thrombosis: Spectrum of Findings

Dang D.; Slone W.; Reddy H.P.; Radiology, Ohio State University, Columbus, OH.

Address correspondence to D. Dang (davidncdang{at}yahoo.com)

Background: Dural sinus thrombosis (DST) is an infrequent but commonly misdiagnosed entity. Presenting symptoms are nonspecific, ranging from headache or nausea to focal neurologic deficits and seizure. There are multiple risk factors including hormonal birth control or replacement, pregnancy, hypercoagulable states, dehydration, infection and trauma. Mortality rate of up to 50% has been reported. Early and accurate diagnosis is essential for successful management. Computed tomography (CT) is the usual initial imaging study. Findings, however, can be subtle or nonexistent and when present can easily be overlooked. Advances in medical imaging including magnetic resonance (MR) venography have led to improved diagnostic accuracy. Here we discuss imaging features, characteristic findings and diagnostic pitfalls of DST in both CT and MR modalities.

Key Issues: This exhibit will describe primary and secondary imaging findings of DST. This includes the appearance of the sinus blood clot on CT and MRI in different stages, and its contrast enhancement pattern. Thromboses in sagittal, transverse, sigmoid and rarely in petrosal sinuses will be discussed. Cases with ischemic or hemorrhagic infarctions will be discussed. Imaging features of normal anatomic variants including hypoplastic and absent sinuses and cases of other pathologies that simulate dural thromboses will be addressed.

Format: This exhibit will be in a didactic. Imaging features in unenhanced CT and MR and contrast enhanced CT venogram and 2-D time of flight and contrast enhanced MR venogram will be described, organized by different sinuses.

Teaching Points: The viewer will learn to 1. Recognize various pathology of the dural sinuses on CT and MR 2. Recognize classic CT and MRI signs of sinus thrombosis 3. Recognize normal variants and imaging pitfalls.

E285. The Pineal Region Revisited: Its All About the Internal Cerebral Veins

Krishnan A.¹; Thorpe J.; Aygun N.A.²; Wilson J.; 1. Neuroradiology and Diagnostic Radiology, William Beaumont Hospital, Royal Oak, MI; 2. Neuroradiology, The Johns Hopkins Hospital, Baltimore, MD.

Address correspondence to A. Krishnan (akrishnan{at}beaumont.edu)

Background: The pineal gland that develops as an out pouching from the roof of the third ventricle is a small but exquisite structure that is flanked superiorly by the internal cerebral veins and the medial posterior choroidal arteries, which lie within the veli interpositum. Its relation to the quadrigeminal plate including compression induced Parinaud's syndrome is well known. This exhibit will attempt to review the anatomy, pathology and differential of conditions close to the pineal region utilizing modern imaging modalities.

Key Issues: In the age of angiography, the displacement of the internal cerebral veins and the medial posterior choroidal arteries as a sign of an underlying pineal mass was well recognized. Yet with cross-sectional imaging some of these features have been forgotten. Understanding the displacement of adjacent structures aids in the identification of the tissue of origin when faced with a large mass of the pineal region. In this exhibit, the common as well as more obtuse causes of masses in this region will be displayed including pineal parenchymal tumors, germ cell tumors, meningiomas, with an initial review of pertinent anatomy of the region to facilitate understanding.

Format: Primarily a discourse on various pathologies of the pineal region. The exhibit will display various causes for pineal region masses and relate them to surgical findings where available. In addition, anatomical drawings shall be discussed.

Teaching Points: 1. Understand the anatomical relations of the pineal region 2. Classify masses based on their location, age of patient and characteristics 3. Develop an understanding of the classification of pineal region masses.

E286. Short Term Follow-up MR Imaging in Gamma Knife Radiosurgery (GKR) Patients with Intracranial and Skull Base Neoplastic Lesions: Goals, Expectations and Pitfalls

Khalatbari K.¹; Azar M.¹; Kazemi Gazic F.¹; Salmanian S.¹; Allahverdi M.¹; 1. Department of Radiology, Iran University of Medical Sciences-Bonyad Kheirieh Kamrani, Gamma Knife Center, Tehran, Tehran, Iran.

Address correspondence to K. Khalatbari (khalatbarik{at}yahoo.com)

Background: In GKR the entire tumor persists immediately after the procedure, thus necessitating close and prolonged imaging follow-up for verification of tumor control. Varying combinations of the therapeutic and harmful effects of radiation results in diverse lesion-evolutionary MRI patterns (with varying significance) between individuals.

Key Issues: The goals of follow-up imaging in GKR patients are: a) Validation of long term tumor control. The definition of tumor control varies - < 25% growth to > 18% volume decrease- for different tumor types; b) Monitoring radiation effects and other complications with the aim of timely intervention; and, c) Corroboration of a histologically-unspecified tumor's behavior with its preliminary diagnosis through time. Awareness of the varying and sometimes alternating patterns of increase and decrease in tumor volumes, especially in the first 2–3 years, is mandatory for preventing inappropriate interventions (e.g., initial growth - secondary to radiation effects - may be followed by ultimate tumor control). A central loss of enhancement has been variably cited as an indirect sign of ultimate tumor control. Radiation effects may be seen either within or outside the tumor. A significant proportion of radiation effects are temporary and asymptomatic. Awareness of the varying appearances and evolutionary patterns of mass lesions following GKR, is mandatory for accurate MRI interpretation.

Format: Illustrative examples of the varying responses of mass lesions to GKR and post-GKR complications.

Teaching Points: - Definition of the goals of post-GKR imaging; - Definitions of tumor control for various pathologic lesions after GKR; - Description of the varying appearances and evolutionary patterns of mass lesions following GKR; - Descriptions of post-GKR complications.

E287. Automatic Brain Extraction of T1-Weighted MRI

Huang A.¹; Abugharbieh R.¹; Tam R.²; Traboulsee A.²; 1. Electrical and Computer Engineering, The University of British Columbia, Vancouver, BC, Canada; 2. Medicine, MS/MRI Research Lab, Vancouver, BC, Canada.

Address correspondence to A. Huang (alberth{at}ece.ubc.ca)

Background: Extracting brain tissues from T1-weighted MRI scans to define the perimeters of the cortex is one of the most important pre-processing steps in measuring intracranial volume and atrophy. The integrity of the brain masks greatly affects the results of subsequent tissue segmentation or other image analysis. Various methods have been developed but results varied from scan to scan.

Key Issues: We introduce an automatic brain extraction algorithm based on a deformable model, namely a geodesic active contour. Outliers are first removed by using hierarchical Otsu thresholds based on varying levels ("low," "normal," or "high") of detected white matter (WM) and gray matter (GM) intensity and contrast. The parameters for our deformable model are then automatically generated and, together with the soft tissue coverage estimated with mathematical morphology and connected component operations, the active contour converges to a stable solution. The output is then post-processed with connected component operations and mathematical morphology for further refinement. For quantitative comparisons with the Brain Extraction Tool (BET), on the 18 synthetic T1-weighted BrainWeb scans, our method achieves < 0.01% and 0.64% improvement over BET in sensitivity and specificity. On 10 selected normal T1-weighted coronal International Brain Segmentation Repository (IBSR) scans with less severe intensity inhomogeneity problem, our method achieves an average of 1.65%, 3.81% and 4.90% improvement over BET in similarity index, misclassification rate and volume difference error. BET fails to exclude eye balls from its brain masks of T1-weighted axial UBC MS/MRI Research Group real study scans, whereas our method captures the cortex more closely. This difference is very visually obvious on the created 3D renderings.

Format: The proposed exhibit will be didactic in format and will be by imaging technique in organizational structure.

Teaching Points: Our novel brain extraction algorithm successfully applies geodesic active contours to a wide variety of T1-weighted head scans. This model is aided by Otsu thresholds, connected component operations and mathematical morphology. Our results proved to be superior quantitatively to those obtained using the state-of-the-art technique, namely BET, on the synthetic BrainWeb and real IBSR T1-weighted scans. Qualitatively on the UBC MS/MRI T1-weighted real study scans, our method visually, in 2D and 3D, outperforms BET in capturing the folds of the soft tissues.

E288. Use of T1 and T2 Relaxation Times Mapping Versus T1- and T2-Weighted Brain Imaging

Lee C.E.; Thomasson D.; Baker E.H.; Diagnostic Radiology, Clinical Center, National Institutes of Health, Bethesda, MD.

Address correspondence to C.E. Lee (leechrist{at}cc.nih.gov)

Objective: Traditionally, T1-weighted images have been used to assess morphology of the brain, while T2-weighted images highlight diseased areas. Recently, however, there has been a trend to apply quantitative measurements to a variety of brain diseases, having found that quantifiable abnormalities are detectable in normal-appearing grey and white matter in diseases such as multiple sclerosis. We propose measuring T1 and T2 relaxation times as a quantifiable measure of potential brain abnormalities.

Materials and Methods: 20 healthy volunteers were studied on a 3T Philips scanner with two different mapping methods. We used a T1 and T2 mapping method provided by Philips, and then, Steady State gradient echo methods (FFE and BFFE) FFE for T1 mapping and BFFE for T2 mapping. Regions of interests were manually placed by a radiologist to measure the T1 and T2 relaxation times in different regions of the brain.

Results: Relative contrast of T1 map to T1W image was 260%, while the relative contrast of T2 map to T2W image was 170% on the same subjects collected in the same imaging session. The FFE and BFFE methods were superior to the Philips method in terms of shorter imaging time and comparability to other published results.

Conclusion: We have confirmed significantly improved relative contrast using T1 and T2 maps. We have also produced an extensive reference table of normal relaxation values for different regions of the brain.

E289. Evolution of Acute and Chronic Black Holes in Secondary Progressive MS with Monthly MRI for 3 Years

Traboulsee A.; Zhao G.; Li D.K.; Medicine and Radiology, University of British Columbia, Vancouver, BC, Canada.

Address correspondence to A. Traboulsee (tony{at}msmri.medicine.ubc.ca)

Objective: Black holes or hypointense lesions on T1-weighted scans in multiple sclerosis (MS), include acute lesions (ABH) which accompany newly active lesions with edema and inflammatory cells, and persistent or chronic black holes (CBH) which are associated histopathologically with axonal loss, correlate with clinical disability and are becoming an MRI outcome for therapeutic trials. We describe the evolution of ABH into CBH.

Materials and Methods: MRI scans were obtained monthly for 3 years in 17 patients with clinically definite secondary progressive MS from a single center and enrolled in the placebo arm of a double blind placebo-controlled therapeutic trial using interferon beta-1a (SPECTRIMS). Two radiologists assessed the scans by consensus for MS lesion activity [new, enlarging proton density/T2 (T2) lesions and T1 gadolinium (Gd-T1) enhancing lesions] and for acute black holes (ABH) on the pre-contrast T1 images in the same location as a newly active MS lesion. ABH that persisted for a minimum of 24 weeks were considered to be CBH. The effect of lesion type on the number ABH evolving into CBH was analyzed using Pearson's Chi-squared test.

Results: 490 Gd-T1 enhancing and 244 active T2 lesions were identified and followed for at least 24 weeks. Of these, 188 (38%) and 163 (67%) had an accompanying ABH, 99% of which appeared at the same time as the active lesion. 48/188 (26%) and 48/163 (29%) ABH became CBH. 71% of ABH disappeared within 4–12 weeks. ABHs and CBHs were more likely with larger lesions. The proportion of Gd-T1 enhancing lesions (< 5, 5–10, > 10 mm) with an accompanying ABH was: 24%, 74% and 100% and for CBH: 5%, 20% and 55%. A similar relationship was seen with the active T2 lesion size. Ring enhancing lesions were more likely to become CBH than nodular enhancing lesions (30% versus 15% of enhancing lesions).

Conclusion: This study illustrates that not all black holes are equal. The majority of ABH (71%) disappear within 12 weeks of appearance representing resolution of edema and/or remyelination. CBH that persist for at least 6 months are unlikely to disappear. These lesions represent more severe axonal loss and tissue destruction. Therapeutic trials that demonstrate an impact on black hole volume without attempting to distinguish ABH from CBH are most likely reflecting the anti-inflammatory effect of the agent under investigation.

E290. Increased Conspicuity of MS Lesions at 3.0 T due to Magnetization Transfer Effect of Fat Suppression Pulse: Preliminary Results of the BECOME Trial

Wolansky L.J.¹; Sheynzon V.¹; Cook S.D.¹; Bhagat N.¹; Turbin R.¹; Frohman L.¹; Rabinowicz A.²; Colaizzi A.²; Dangond F.²; Cadavid D.²; 1. Radiology, New Jersey Medical School/University of Medicine & Dentistry of New Jersey, Newark, NJ; 2. R&D, Berlex Labs, Wayne, NJ.

Address correspondence to L.J. Wolansky (wolanslj{at}umdnj.edu)

Objective: To investigate whether a chemical shift based fat-suppression pulse improves conspicuity of Gadolinium enhancing MS lesions at 3.0 T due to off-resonance excitation creating a magnetization transfer contrast (MT) effect.

Materials and Methods: Seven MS subjects from the BECOME trial (Betaseron vs. Copaxone in MS with triple-dose Gadolinium and 3.0 T MRI Endpoints) were studied without and with a chemical shift based fat suppression pulse at 3.0 T. Region of interest (ROI) measurements were carried out for 50 enhancing lesions. A respective area of "normal appearing white matter" (NAWM) was also evaluated on each section. The magnetization transfer ratio (MTR) was determined as follows: [(ROI without fat-suppression – ROI with fat-suppression) / ROI without fat-suppression] An objective measure of conspicuity, the image contrast ratio (ICR), was determined as follows: [ROI (lesion) – ROI (white)]/ROI(white).

Results: All 50 lesions demonstrated decreased signal with fat-suppression. The mean lesion MTR was 13.4%. All 36 areas of white matter demonstrated decreased signal with fat-suppression. The mean white matter MTR was 23.9%. The mean ICR was 0.89 for fat-suppressed images and 0.66 for non-fat-suppressed images.

Conclusion: Evidence suggests that at 3.0 T a chemical shift based fat suppression pulse can be used to produce magnetization transfer contrast. Since the suppression is more intense for white matter than for lesions, probably due to the high concentration of macromolecules in myelin, the suppression increases enhancing lesions conspicuity.

E291. Diffuse axonal injury in closed head injury: Imaging findings

Zheng W.B.; Liu G.R.; Fang W.H.; Radiology, Second Hospital, Shantou University Medical College, Shantou, Guangdong, China.

Address correspondence to W.B. Zheng (HWENB{at}21CN.COM)

Objective: The purpose of this work was to compare computed tomography with conventional MR and diffusion-weighted imaging (DWI) in the detection of shearing injuries in acute and subacute diffuse axonal head injuries.

Materials and Methods: Seventy four adult patients (48 male and 26 female patients) with diffuse axonal injury were examined within 2 hours to 20 days of trauma by computed tomography, conventional MRI and T2-weighted echo-planar sequences. Convention MR imaging consisted of fluid-attenuated inversion recovery, T2-weighted fast spin-echo, and T2-weighted gradient-echo sequences. Diffusion-weighted imaging was performed using spin-echo echo-planar sequence. Lesions were identified and compared on all imaging.

Results: Three hundred and seventy-seven shearing lesions were counted by the combined use of all imaging. Among them, 307 lesions were nonhemorrhagic (81.4%) and 70 lesions were hemorrhagic (18.6%). Diffusion-weighted imaging depicted the largest number of lesions (317/377), followed by FLAIR (226/317), T2-weighted fast SE (184/377), T2-weighted GRE sequences (170/377) and the lowest number of lesions were depicted by CT (95/377). Of the 317 lesions depicted on diffusion-weighted images showed decreased diffusion on ADC maps. Among the 74 patients, 35 (47%) had lesions in the brainstem, 34 (46%) had lesions within the basal ganglia and/or thalamus, and 47 (67%) had injuries of the corpus callosum. Only fifteen (21%) of 74 patients had traumatic lesions in all three locations. DWI identified 91 lesions not seen on conventional MRI. The signal intensity of 134 lesions (35.5%) on DWI was higher than that on T2-FSE. T2-weighted GRE sequences and CT identifies twenty hemorrhagic shearing injuries not visible on T2-FSE and diffusion-weighted imaging (DWI).

Conclusion: In the detection of the nonhemorrhagic shearing injuries in acute and subacute diffuse axonal head injuries, conventional MR is more sensitive than computed tomography, DWI is more sensitive than conventional MR because it detects additional shearing lesions. T2-weighted GRE sequences and CT is more sensitive than T2-FSE, T2-Flair and DWI in the detection of the hemorrhagic shearing injuries.

E292. Imaging Findings in Patients with Heat Stroke: Correlation with Clinical Features

Kim KK.¹; Kim SS.²; Nam E.²; Lee KU.²; 1. Neurology, Kangwon National University Hospital, Chuncheon, South Korea; 2. Radiology, Kangwon National University Hospital, Chuncheon, South Korea.

Address correspondence to KK. Kim (neukim{at}knuh.or.kr)

Objective: Heat stroke is a thermal insult to the cerebral thermo-regulatory system that control heat production and heat dissipation. The purpose of this study was to correlate imaging findings with clinical features.

Materials and Methods: Enrolled were six patients diagnosed as heat stroke on the basis of neurological criteria. All patients underwent both brain MR and PET examination from on the day to 30 days after symptoms onset and three patients performed follow up MR imaging. Medical records and imaging findings were retrospectively analyzed.

Results: All patients showed altered mentality in the acute stage. During the subacute to chronic stage, cerebellar ataxia showed in five patients, gaze-evoked nystagmus in four, abulia in one, visual agnosia in one, respectively. Brain MRI also showed various findings normal (n = 3), white matter change (n = 1), extensive brainstem and thalamic signal change (n = 1), respectively at initial images. In one patient, severe progressive cerebellar atrophy was shown on follow-up images up to 1 year. PET image showed cerebellar hypometabolism in 5 patients, hypometabolism in the frontal lobe in 4, and the posterior temporo-occipital lobe in 3, respectively.

Conclusion: Heat stroke may demonstrate various neurological deficits and brain imaging abnormalities including cerebellar atrophy. Brain MRI and PET imaging are well correlated with clinical features of patients with heat stroke.

E293. Neurovascular Application of Time Resolved MR Angiography with Parallel Imaging: Initial Experience

Jung S.L.¹; Hwang M.J.²; Kim B.S.¹; Ahn K.J.¹; Kim J.Y.¹; Lee J.M.¹; 1. Radiology, Kangnam St. Mary's Hospital, The Catholic University of Korea, Seoul, South Korea; 2. GE Healthcare, Seoul, South Korea.

Address correspondence to S.L. Jung (sljung1{at}catholic.ac.kr)

Objective: Having trade-off between the spatial resolution and frame rate, time-resolved contrast-enhanced MR angiography (CE MRA) provides dynamic temporal information without significant degradation of spatial resolution. Parallel imaging permits shorter imaging time with acceptable image quality. The purpose of this study is to evaluate elliptical centric time resolved imaging on contrast kinetics (ECTRICKS) CE MRA with parallel imaging (array spatial sensitivity encoding technique (ASSET)) in a series of patients with neurovascular abnormalities.

Materials and Methods: Patients with suspected/known neurovascular disease or intracranial tumor were imaged using a 1.5 T whole body MR scanner (Signa Twinspeed, GE Healthcare, Milwaukee, Wis). A 3D multiphase ECTRICKS pulse sequence was combined with parallel imaging (ASSET). Gadolinium-based contrast material (Magnevist or Gadovist, was administered as a single to double dose in an antecubital vein.

Results: We have successfully imaged brain AVM, aneurysm, intracranial tumors including meningiomas, hemangioblastoma and metastasis with intratumoral shunt, venous reflex of internal jugular vein during intravenous contrast injection on antecubital vein, and status post trapping of cavernous internal carotid artery. We achieved high resolution time resolved MRA at the frame rates of 2 to 3 seconds, with targeted slab applied in axial, coronal or sagittal plane according to the location of the lesion.

Conclusion: We have successfully combined time resolved CE MRA (ECTRICKS) with parallel imaging (ASSET) imaging for high-resolution and high-frame rate MRA in the evaluation of neurovascular disease and intracranial tumor. Our initial experience regarding the trade-off between spatial and temporal resolution, usage of Ga-based contrast materials, application of imaging plane and slab according to the location and type of the lesion will be presented.

E294. Brain CT Perfusion in Asymptomatic Elderly Patients: Is there any Correlation with Internal Carotid Stenosis?

Cesari S.¹; Balestreri L.²; Bidoli E.²; Liessi G.¹; Visonà A.¹; Morassut S.²; 1. Radiology, Ospedale Civile, Castelfranco Veneto, Italy; 2. Radiology, Centro Riferimento Oncologico Aviano, Aviano, Italy.

Address correspondence to S. Cesari (scesari{at}libero.it)

Objective: To investigate if any correlation exists between brain perfusion measured with CT Perfusion technique (CTP) and carotideal stenosis measured with Doppler Ultrasound (DUS) in an elderly population without neurological symptoms.

Materials and Methods: Sixty-three patients with median age of 71 years without neurological symptoms were studied with DUS to assess the degree of eventual carotideal stenosis. The stenosis was considered present if superior to 30% of the vessel axial diameter. Perfusion CT of both cerebral hemispheres was performed with a 8 rows multislice scanner drawing regions of interest and data were analyzed with dedicated software. Blood Volume (BV), Blood Flow (BF) and Mean Transit Time (MTT) were evaluated and correlated to the presence of carotideal stenosis. The sample was described by means of mean and standard deviation. Comparison between left and right carotideal stenosis, if any, and the degree of cerebral perfusion were computed using Mann-Whitney non-parametric test. p value was considered statistically significant when < 0.05.

Results: No association was found between the presence of carotideal stenosis and eventual decrease of brain perfusion measured with CTP. The mean BV, BF and MTT were 1.65, 29.44 and 4.30, respectively.

Conclusion: In neurologically asymptomatic elderly patients the reduced brain perfusion measured with CTP does not correlate to the presence of eventual carotideal stenosis. However, the overall values of brain perfusion parameters are lower than expected and may be related to asymptomatic changes in local vascular micro-circulation.

E295. Dosing of Gadobenate Dimeglumine in MR Imaging of Brain and Spine Metastatic Disease

Runge V.M.¹; Ross J.²; Nelson K.L.²; 1. Department of Radiology, Scott & White Clinic, Temple, TC; 2. Department of Radiology, Cleveland Clinic Foundation, Cleveland, OH; 3. Department of Radiology, Methodist Hospital, Omaha, NE.

Address correspondence to V.M. Runge (runge{at}att.net)

Objective: To determine whether the increased T1 relaxivity of gadobenate dimeglumine (Gd-BOPTA; MultiHance; 9.7 L•mmol-1•s-1) permits a lower dose to be used for detection of CNS metastases.

Materials and Methods: 149 patients with CNS metastases received Gd-BOPTA at either 0.05 (n = 74) or 0.1 mmol/kg (n = 75). T1w and T2wSE images were acquired pre-dose followed by T1w images at 10 min post-dose. Three fully blinded neuroradiologists qualitatively evaluated in randomized order pre-dose images alone and pre+post-dose images combined. Five-point scales from 0 = none to 4 = excellent were used to compare the doses in terms of changes from pre-dose in lesion border delineation, visualization of internal lesion morphology and contrast enhancement of lesions. Quantitative evaluations of lesion-to-background ratio, contrast-to-noise ratio and % enhancement were performed on pre- and post-dose T1w images. Data were evaluated using paired t-tests and analysis of covariance. Inter-reader agreement was also evaluated.

Results: Pre- to pre+post-dose increases in score were significant (p < 0.001) for each reader for all qualitative parameters. Each reader noted greater increases for the 0.1 mmol/kg group compared to the 0.05 mmol/kg group. Inter-reader agreement was good for all qualitative parameters and image sets. Quantitative evaluation revealed significant (p < 0.001) increases post-dose for each parameter and consistently higher values for the 0.1 mmol/kg group. Two readers detected significantly (p < 0.05) more lesions post-dose in the 0.1 group compared to the 0.05 group for all patients combined and for patients with 0–2 lesions on pre-dose images.

Conclusion: A 0.1 mmol/kg dose of Gd-BOPTA improves both lesion detection and image quality.

E296. Imaging the Craniospinal Junction

Rajiah P.; Shabani A.; Khan A.; Radiology, Royal Manchester Children's Hospital, Manchester, United Kingdom.

Address correspondence to P. Rajiah (rprabhakar73{at}yahoo.com)

Background: Craniocervical junction is involved in a variety of conditions, which include congenital, developmental, traumatic, infective, inflammatory and neoplastic lesions. Pathology in this region can result in compression of brainstem, spinal cord, cranial nerves, cervical roots and vascular structures. Multidetector CT and MRI scan have revolutionized the imaging of this critical region.

Key Issues: X-ray is the basic investigation used for evaluating craniocervical junction lesions. Multidetector CT with multiplanar reconstruction and MRI were obtained for further information. The pathologies illustrated include congenital(Chiari malformation, syringomyelia, achondroplasia, mucopolysaccharidosis, pyknodysostosis, Downs syndrome, Klippel Fleil malformation), traumatic(fractures-Jefferson, Hangman's etc, dislocations), bony abnormalities(atlantoaxial subluxation, basilar invagination, platybasia, assimilation of atlas) infections (TB, pyogenic, Griesel's syndrome), inflammatory (Rheumatoid, gout, pseudogout, ankylosing spondylitis, Pagets disease) and tumors (Ewings sarcoma, metastasis, lymphoma, etc.)

Format: The presentation discusses the normal development, anatomy and imaging techniques of the craniospinal junction. The pictorial review illustrates all the pathologies affecting the craniospinal junction with ample demonstration of the use of each imaging modality.

Teaching Points: A. To learn the development and anatomy of craniocervical junction Baton understand the role of imaging in assessing the craniocervical junction, especially multidetector CT and MRI. Cato illustrate X ray, CT and MRI appearances of various pathologies affecting craniocervical junction.

E297. Disorders of the Spine Arising from Faulty Canalization and Retrogressive Differentiation

Marino T.; Huang B.; Oljeski S.; Castillo M.; Neuroradiology, University of North Carolina at Chapel Hill, Chapel Hill, NC.

Address correspondence to T. Marino (tmarino{at}unch.unc.edu)

Background: Several mechanisms are responsible for the development of the distal most portion of the spine. The process by which the inferior aspect of the neural tube elongates is called canalization. During canalization, the neural tube joins the caudal cell mass which is composed of notochord and neural elements. Apoptosis leads to a decreased size and reorganization of the caudal cell mass and central lumen in a process known as retrogressive differentiation. Here we will illustrate abnormalities that result from abnormal canalization and retrogressive differentiation.

Key Issues: The normal embryology of the distal spine will be briefly reviewed. Relevant images will then illustrate the disorders resulting from defective canalization and retrogressive differentiation including the caudal regression syndrome, ventriculus terminalis, filar lipoma, tight filum terminale syndrome, and sacrococcygeal teratoma. The emphasis is on MR imaging, however, selective US images will also be presented.

Format: Our presentation will be a didactic electronic exhibit in the format of a pictorial essay, illustrating the imaging features associated with abnormal canalization and retrogressive differentiation.

Teaching Points: The purpose of the exhibit is to illustrate congenital abnormalities arising in the distal spine from faulty canalization and retrogressive differentiation. The importance of knowledge of the normal embryologic development of the caudal spine in understanding the pathologic conditions that can result will also be demonstrated.

E298. To Evaluate the Accuracy of the Vertebrogram in Predicting Cement Filling Patterns with Percutaneous Vertebroplasty

Ormsby E.L.; Dublin A.B.; Radiology, University of California At Davis Medical Center, Sacramento, CA.

Address correspondence to E.L. Ormsby (eleanor.ormsby{at}ucdmc.ucdavis.edu)

Objective: To evaluate the accuracy of the vertebrogram in predicting cement filling patterns with percutaneous vertebroplasty.

Materials and Methods: 75 fracture vertebral levels were injected by a uni-pedicle approach with iodinated contrast material. This filling pattern was compared to the cement deposition pattern of the percutaneous vertebroplasty.

Results: 35 levels showed excellent cross filling and matched pattern by vertebrogram and cement deposition (47%). 10 cases (13%) showed cross filling by both techniques, with less than 100% matched pattern, but and were considered adequate for fracture treatment. 4 cases (5%) showed predominantly matched central filling, considered adequate for fracture treatment. 21 cases (28%) showed only matched filling of of the vertebral body with both techniques, necessitating a bi-pedicle approach for treatment with cement. The remaining cases demonstrated mismatched patterns between the vertebrogram and the cement deposition, and were not helpful in predicting the success of a single or double pedicle technique.

Conclusion: The pre-cement deposition use of the vertebrogram was helpful in predicting adequate cement deposition, using a single pedicle, in 49 of 75 cases (65%). The vertebrogram was helpful in predicting the need for a double pedicle technique in an additional 21 cases (28%). Therefore, the vertebrogram was very helpful in predicting the route of cement deposition in 93% of cases, and should be considered as an adjunct to percutaneous vertebroplasty technique.

E299. 64-slice CT: Detector Technology, Clinical Applications and Potential Pitfalls in Head and Neck Imaging

Srinivasan A.; Case I.; Mukherji S.K.; Department of Radiology, University of Michigan Health system, Ann Arbor, MI.

Address correspondence to A. Srinivasan (ashoks{at}med.umich.edu)

Background: 64-slice CT represents a breakthrough in CT technology and provides increased coverage, decrease scanning time and excellent 3D capabilities. Various applications in head and neck imaging include CT angiography, CT perfusion, temporal bone imaging (with detailed 3D models of bony ossicles and labyrinth), and laryngeal imaging.

Key Issues: CT angiogram of both extracranial and intracranial vessels can be performed between 4–6 seconds, reducing the likelihood of image degradation by motion or swallowing artifacts. The increased tissue coverage on CT perfusion studies using a 64-slice CT (4 cm) may be useful in acute stroke patients when planning intervention and in perfusion imaging of head and neck tumors. Routine temporal bone imaging is now performed at 0.625 mm and results in exquisite 3D reconstructions comparable to direct coronal acquisitions. Some potential concerns using 64-slice CT are the increased amount of data, radiation dose and timing delays. Optimization of detector configuration can result in decreased radiation exposure using 64-slice scanner compared to similar acquisition using 16-slice scanner. Improper timing delay can result in `Outrunning the bolus' and hence it may be essential to individualize the delay in each patient and institution.

Format: Didactic format structured as follows:- 1. Detector technology and configuration 2. Various vendors of 64-slice CT with comparison of the existing machines 3. Acquisition parameters in head and neck imaging 4. Clinical applications in head and neck imaging 5. Potential pitfalls of 64-slice CT.

Teaching Points: Learning Objectives: 1. Review the detector technology and configuration intrinsic to 64-slice multidetector CT. 2. Highlight the applications of 64-slice CT in different subsites of the extracranial head and neck. 3. Discuss the acquisition parameters in the extracranial head and neck to optimize dose reduction from 64-slice imaging that occurs from "scanning thin and viewing thick." 4. Discuss the potential pitfalls of 64-slice CT in head and neck imaging.

E300. Vascular vs. Nonvascular Orbital Masses – How to Avoid Misdiagnosis

Poon C.S.; Johnson M.H.; Division of Neuroradiology, Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, CT.

Address correspondence to C.S. Poon (cpoonmd{at}yahoo.com)

Background: Differentiation between a vascular and nonvascular orbital mass is important, as it may direct the appropriate approach for further workup and ultimate management. Although one may think these lesions should be easily differentiable on imaging studies, we have encountered several cases where vascular lesions were suspected both clinically and by imaging but were subsequently proven to be non-vascular, leading to a surprise final diagnosis. Understanding of orbital vascular anatomy, the use of appropriate imaging techniques, and using a few clues to image interpretation will help one to avoid diagnostic pitfalls. A correct diagnosis can often be achieved even when lesions mimic each other.

Key Issues: In this presentation, we will review the anatomy of the orbits with particular attention to both arterial and venous structures. We will demonstrate cases of vascular and nonvascular orbital masses, with emphasis on their differentiating radiological features. Soft tissue orbital mass lesions that have been mistaken for vascular lesions on CT and MRI, such as neurofibroma, metastases, and even variations in orbital venous drainage patterns are included along with clues to the correct diagnosis. The diagnostic pitfalls and approach for evaluation using advanced imaging techniques such as contrast-enhanced MRI, MRA, and CT angiography will be discussed and illustrated.

Format: This is a pictorial essay presented as a Microsoft PowerPoint presentation. Interactive cases will be included in the presentation.

Teaching Points: Vascular and nonvascular orbital lesions may mimic one another on clinical presentation and imaging studies. By a good understanding of the orbital vascular anatomy, appropriate use of imaging technology, and careful analysis of the imaging features, one can avoid the pitfalls in radiological diagnosis. Traditionally, many of these cases are referred to interventional neuroradiology for evaluation. With the advance of multidetector CT technology, CT angiography becomes a viable non-invasive option for early workup in addition to the routine use of MRI/MRA. This will minimize unnecessary invasive angiographic procedures, ultimately leading to better patient care.

E301. The Thyroid Conundrum: Selecting Nodules for Fine Needle Aspiration

Friedman E.R.; Chandrasekhar C.; Department of Diagnostic and Interventional Imaging, University of Texas Health Science Center at Houston, Houston, TX.

Address correspondence to E.R. Friedman (Elliott.R.Friedman{at}uth.tmc.edu)

Background: The use of ultrasonography in the evaluation of thyroid and nonthyroid disease has resulted in a dramatic increase in the number of detected thyroid nodules. Additionally, incidental thyroid lesions are frequently detected on CT and MRI scans of the neck performed for nonthyroid indications. Despite the common prevalence of thyroid nodules, most nodules are benign, and only the malignant or large symptomatic nodules require surgery. The high sensitivity and specificity of fine needle aspiration biopsy (FNAB) makes it an accurate and cost-effective procedure for distinguishing benign from malignant nodules, resulting in a decrease in the number of patients requiring thyroidectomy and increasing the malignancy yield of surgery. The appropriate clinical management, including the prudence of FNAB, in the workup of sonographically detected thyroid nodules is a complex and debated topic. The recommendations of the Consensus Conference on Management of Thyroid Nodules will provide guidelines for categorizing thyroid nodules and the appropriateness of FNAB.

Key Issues: This poster will review the benign and malignant sonographic features of thyroid disease. Categorization based on the Thyroid Consensus will provide guidelines for determining which thyroid nodules detected by sonography require fine needle aspiration.

Format: This presentation will utilize a didactic format to review the spectrum of sonographic features of benign and malignant thyroid nodules. Sonographic images will be correlated with pathologic findings from biopsy. Each of the described characteristics of thyroid nodules will be organized according to the guidelines released by the Thyroid Consensus with regard to the appropriateness of fine needle aspiration biopsy.

Teaching Points: 1. To understand the sonographic presentation of thyroid disease with discussion of the sonographic features that differentiate benign from malignant nodules. 2. To elucidate the Thyroid Consensus with regard to the accepted standards for fine needle aspiration biopsy.

E302. Imaging in Acute Torticollis

Huang B.Y.; Marino T.F.; Oljeski S.A.; Castillo M.; Radiology, University of North Carolina, Chapel Hill, NC.

Address correspondence to B.Y. Huang (bhuang{at}unch.unc.edu)

Background: Torticollis refers to the presentation of the head in an abnormal twisted or bent position. It can be congenital or acquired and can represent a primary disease entity or a symptom of an underlying pathologic condition. While most cases of acute torticollis are due to `benign' etiologies which can be managed conservatively, the list of disease entities which may present with acute torticollis is extensive. Appropriate diagnosis and treatment of the underlying cause of torticollis is important not only because of the pain and debilitation directly associated with the deformity, but also because of the potential chronic complications, both physical and psychiatric, that can occur if the condition is left untreated.

Key Issues: Congenital torticollis is most often due to fibromatosis colli, a fibrous contracture of the sternocleidomastoid muscle which is believed to be due to birthtrauma or abnormal head positioning in utero. Fibromatosis colli has a typical clinical presentation, and ultrasound is usually the only imaging study required in its evaluation. Acquired torticollis, on the other hand, may be idiopathic or due to a myriad of causes including trauma; infectious or inflammatory conditions of the spine, airway, or central nervous system; spine or central nervous system neoplasms; neuroleptic drugs; ocular muscle abnormalities; and spinal cord abnormalities such as syringohydromyelia. Imaging evaluation of patients with acquired acute torticollis is often necessary to exclude more ominous causes, and radiologists play a key role in directing management and/or need for additional testing in these patients. Imaging of acute torticollis may include plain radiographs, CT, ultrasound, or MRI, and the choice of imaging modality depends on patient age and clinical presentation.

Format: This presentation is in the form of a didactic electronic exhibit. We review several of the potential causes of acute torticollis, both congenital and acquired, and the typical imaging characteristics of these entities are demonstrated. Finally, we present a practical imaging algorithm for patients presenting with acute torticollis.

Teaching Points: The goal of this presentation is to familiarize radiologists with the entity of acute torticollis and its etiologies, thus enabling them to advise referring clinicians effectively on the appropriate radiologic workup of the condition and ultimately to aid in diagnosing its underlying causes.

E303. Scleroma of the Upper Respiratory Airway: MR and CT Imaging Features

Abdel Razek A.A.¹; Bilal M.Z.¹; Monier S.¹; Shabana Y.²; Rizk N.²; 1. Diagnostic Radiology, Mansoura University Hospital, Mansoura, DK, Egypt; 2. ENT, Mansoura University Hospital, Mansoura, DK, Egypt.

Address correspondence to A.A. Abdel Razek (arazek{at}mans.eun.eg)

Background: Scleroma is granulomatous disease affecting the upper respiratory airway. Imaging is needed to detect the extent of the disease.

Key Issues: A retrospective reviewing of MR and CT scan of 39 patients (21 M, 18 F, aged 12–34ys) with pathologically proven scleroma of the upper airway was performed. Twenty patients at hypertrophic stage and rest of patients at atrophic or sclerotic stages. Nasal scleroma (n = 21) appeared as bilateral or unilateral localized infiltrative or expanding bulky mass with thinned septum and displaced sinus wall. Thickened palate and tonsillar pillar was seen in pharyngeal scleroma (n = 4). There was circumferential enhancing soft tissue mass encircling the subglottic region (n = 15) with irregular thickening of epiglottis & aryepiglottic folds (n = 2). There was focal or diffuse small crypts like irregularity of the tracheal wall (n = 6) with variable extension into the central bronchi (n = 2). Enlarged cervical lymph nodes was seen in 2 patients. We concluded that MR imaging and CT can determine extent of scleroma of the upper respiratory airway. This information is important for treatment planning of these patients.

Format: The format will be didactic and organization structure will be by location.

Teaching Points: To review the demographic, pathological stages and clinical manifestations of scleroma of the upper respiratory airway. To demonstrate MR & CT imaging features in patients with scleroma of the upper respiratory airway.

E304. Imaging in Acute Facial Nerve Paralysis

Hollingshead M.C.; Castellano F.; Pulnik J.; Castillo M.; Radiology, University of North Carolina at Chapel Hill, Chapel Hill, NC.

Address correspondence to M.C. Hollingshead (mholling{at}unch.unc.edu)

Background: The majority of cases of acute facial nerve paralysis are of the Bell's type. While magnetic resonance (MR) imaging is not necessary in the diagnosis of typical Bell's palsy, when employed it can demonstrate abnormalities of the facial nerve. For patients with atypical or unusual symptoms, however, imaging is critical in their evaluation. These patients can have a variety of underlying pathology ranging from atypical Bell's palsy to malignancy, infection, or trauma.

Key Issues: We reviewed our experience with patients with a clinical history of acute facial nerve palsy. Relevant images were identified to illustrate the wide variety of causes of acute facial nerve palsy. Knowledge of the anatomy of the facial nerve is necessary for proper evaluation and diagnosis. Its course is briefly reviewed. The clinical and imaging features of Bell's palsy, both typical and atypical, are illustrated. Further, we examine other causes of acute facial nerve paralysis including trauma to the temporal bone, infection, Wegener granulomatosis, and a variety of tumors including hemangioma, Schwannoma, parotid carcinoma, glomus jugulo-tympanicum tumor, meningioma, and rhabdomyosarcoma. A brief review of Melkersson-Rosenthal syndrome is also included.

Format: This will be an interactive electronic exhibit created using PowerPoint. The anatomy of the facial nerve is briefly reviewed. Clinical and imaging features of typical and atypical Bell's palsy as well as other causes of facial nerve paralysis are illustrated through text and images. The emphasis is on the benefit of MR imaging, but images from computed tomography (CT) are also included.

Teaching Points: While typical Bell's palsy does not require imaging for diagnosis, radiologic evaluation, particularly with MRI, is crucial in the evaluation of patients with atypical or unusual presentations of acute facial nerve paralysis.

E305. MDCT of the Temporal Bone Anatomy: Interactive Exhibit

Kay F.U.; Soares C.S.; Cevasco F.K.; Gebrim E.M.; Cerri G.G.; Gomes R.L.; Departamento de Radiologia do Hospital das Clínicas da FMUSP, Instituto de Radiologia do Hospital das Clínicas da FMUSP, São Paulo, SP, Brazil.

Background: High-resolution CT is an established method used to study the temporal bone. The anatomy of the temporal bone is complex, and its characterization requires the use of thin slices and high resolution algorithms. Since the advent of multidetector computed tomography (MDCT), a better evaluation of the temporal bone has become possible. The use of thin slices based protocols, and the possibility of multiplanar reformations facilitated the characterization, and evaluation of different anatomical landmarks. As a result, new efforts have to be made in order deal with this new paradigm.

Key Issues: The exhibit will address the most important anatomical landmarks of the temporal bone, as well as other specific landmarks, which are better seen on MDCT images. MDCT images of the temporal bones were acquired in the axial plane with Philips MX8000 IDT 16-row and 10-row 0.75-mm detector scanners. Scans were acquired in the helical mode, and the parameters were 120 kV, 180 mAs, 1-mm section thickness, and 0.5-mm reconstruction increment. We used high-spatial-frequency reconstruction algorithms. Multiplanar reformations were used to better demonstrate different anatomical structures to the viewer.

Format: The present exhibit will focus on interactive exercises based on MDCT images showing key anatomical findings of the temporal bone. Exercises will be organized by anatomical structure (i.e. middle ear anatomy, cochlear anatomy, vestibular anatomy, facial nerve canal etc.). The viewer is then expected to further learn and understand the temporal bone anatomy by practice.

Teaching Points: - Familiarize the radiologist with the current use of MDCT in the evaluation of the temporal bone anatomy. - Demonstrate the most important landmarks of the temporal bone anatomy. - Review specific anatomical landmarks better characterized on MDCT images.

E306. Temporal Bone Multiplanar Imaging: A Practical Review of CT and MR Anatomy, Temporal Bone Pathology and Self-Assessment Examination

Vidal J.A.^1,2; Akhtar N.²; 1. Radiology, University of Missouri at Kansas City, Kansas City, MO; 2. Radiology, Saint Lukes Hospital, Kansas City, MO.

Address correspondence to J.A. Vidal (vidalja{at}umkc.edu)

Background: Temporal bone imaging has gained increased popularity with the development of thinner and faster Multidetector CT as well as better MRI techniques and coils. The anatomy has traditionally been somewhat intimidating to General Radiologists and Radiology Residents who do not deal with it on a regular basis. The Radiologist nonetheless must continue to provide an excellent service to the referring clinicians who depend on these studies for the treatment of temporal bone pathology.

Key Issues: The temporal bone, inner ear, middle ear, external ear, and cerebellopontine angle regions possess very intricate and small anatomy. The development of MDCT and MRI has allowed the Radiologist to image these structures with exquisite detail, never before seen. However, this can be intimidating to some Radiologist and Residents who do not deal with the anatomy on a regular basis. This exhibit will show the normal anatomy, describe an algorithm for evaluating the structures involved and identifying pathology. MRI and MDCT examples will be used with and without labels, followed by a brief self-assessment exam.

Format: The exhibit will begin with a didactic presentation of temporal bone anatomy seen on MDCT and MRI. The normal anatomy will be discussed initially, followed by a presentation of normal variants. This will be followed by a series of cases showing different types of pathology and their respective teaching points as well as clinical pearls. Finally, the exhibit will conclude with a brief self-assessment test in which the viewer will be able to put all the concepts together to reach a diagnosis in multiple cases.

Teaching Points: The viewer will be able to review temporal bone anatomy on both MRI and MDCT on multiple planes. After a brief tutorial, the viewer will see a vari-ety of cases with and without pathology. The exhibit will conclude with a brief self-assessment test which will highlight the concepts that were discussed during the tutorial. The ultimate goal of the exhibit is to refresh and present temporal bone anatomy in a systematic and user-friendly approach so the radiologists can develop confidence in their interpretations.

E307. Congenital and Acquired Hearing Loss: a Review with Emphasis on MRI Findings

Oljeski S.A.; Marino T.F.; Huang B.; Castillo M.; Radiology, University of North Carolina Hospitals, Chapel Hill, NC.

Address correspondence to S.A. Oljeski (SOljeski{at}unch.unc.edu)

Background: We reviewed our teaching files for MRI and CT studies of the temporal bones in adult and pediatric patients with both congenital and acquired deafness. For the last three years, patients with hearing loss have routinely received both MRI and CT at our institution. From this group of patients we chose representative images to illustrate the variety of disorders found.

Key Issues: Imaging findings for multiple causes of hearing loss including: congenital cochlear and modiolar dysplasias, vestibular dysplasias, aplasia and hypoplasia of the cochlear nerve(s), anomalies of the vestibular aqueduct and endolymphatic sac, tumors, trauma, and non-neoplastic mass lesions such as cholesteatomas, will be reviewed with emphasis on their MRI features. In addition, we will review the utility of MRI in the evaluation of fibrosing and ossifying labyrinthitis.

Format: Didactic format organized by pathology.

Teaching Points: The causes of hearing loss widely vary and MRI studies add important information. Correct interpretation of imaging findings, particularly those seen on MRI studies, may prove critical to the diagnosis and treatment of such patients.

E308. A Reclassification of Temporal Bone Fractures and Its Association with Facial Nerve Injury

Kubo M.; McCulloch T.M.; Kim P.; Raske M.; Anzai Y.; Cohen W.A.; Whipple M.E.; Radiology, Harborview Medical Center, Seattle, WA.

Address correspondence to M. Kubo (mkubo{at}u.washington.edu)

Objective: Historic methods of classifying temporal bone fractures poorly correlate with clinical findings. An effective and simple way of correlating radiological findings in temporal bone fractures with complications like facial nerve injury would better guide patient management. We hypothesize that a classification system based on the medial extent of a fracture enhances prediction of facial nerve injuries.

Materials and Methods: Retrospective chart review identified 109 patients with 131 temporal bone fractures. Temporal bone CT scan and a record of facial nerve evaluation were available for 115 fractures in 99 patients. CT scans were reviewed and fractures were classified by our proposed system and by the traditional system (longitudinal, transverse and mixed). Our proposed system classifies fractures by the most medial involvement. Group A is lateral, involving the mastoid, external auditory canal, and/or the temporomandibular joint, Group B involves the tympanic cleft, Group C involves the course of the facial nerve and Group D the otic capsule. Fractures were grouped according to the classification schemes and correlated with clinical reports of facial nerve dysfunction.

Results: 16 of the 115 fractures had associated facial nerve weakness or paralysis. Using the new classification scheme, facial nerve injury was present as follows: Group A - 0/20 (0%), Group B - 5/55 (9%), Group C - 6/31(19%) and group D - 5/9 (56%). Using the traditional classification system, facial nerve dysfunction was present as follows: longitudinal fractures –9/72 (13%), transverse fractures –4/21 (19%) and mixed fractures –3/22 (14%).

Conclusion: Our new system for classifying temporal bone fractures, compared to the traditional classification system, has a higher correlation with facial nerve injury. This simple system can help physicians triage patients and predict those patients at risk of facial nerve injury.

E309. Virtual Laryngoscopy in Assessment of Subglottic Stenosis

Abdel Razek A.¹; Ezzat A.¹; Elhashash D.¹; Rizk N.²; Kamel Y.²; 1. Diagnostic Radiology, Mansoura University Hospital, Mansoura, DK, Egypt; 2. ENT, Mansoura University Hospital, Mansoura, DK, Egypt.

Address correspondence to A. Abdel Razek (arazek{at}mans.eun.eg)

Objective: Subglottic stenosis is still one of the most challenging problems for endoscopy as it is difficult to diagnosed with conventional laryngoscopy (CL). So, our aim is to demonstrate the role of virtual laryngoscopy (VL) in patients with subglottic stenosis.

Materials and Methods: This study included 28 patients (17M and 11F aged 5–65ys) suspected to have subglottic stenosis. They presented with stridor (n = 21), hoarseness of voice (n = 18) and airway obstruction (n = 7). Post IV contrast spiral CT scan of the neck and VL and CL were done for all patients. The scanning parameters were 2-collimation, 6 mm/sec table speed, 1 mm reconstruction intervals, 1.5 mm slice thickness and 1.7 pitch. Helical CT and VL images were reviewed to estimate the level, extent, degree and cause of stenosis. We compared the results of helical CT, VL with CL findings.

Results: This study included post intubation (n = 10), granulomatous (n = 6), neoplastic (n = 5), post traumatic (n = 4), and congenital (n = 3) subglottic stenosis. The vertical extent of stenosis delineated with VL in all patients and could not be measured with CL in 3 patients. virtual laryngoscopy determined the extent of stenotic lesion into the trachea (n = 5) and demonstrated the relationship between the stenotic region and the true vocal cord. Also, it accurately measured the degree of subglottic stenosis. Correlation of subglottic stenosis shape and contour between CL and VL was noted in 25 patients. Axial plane differentiated subglottic soft tissue scar and mass (n = 18) from cartilage stenosis (n = 4) and displacement (n = 2). Also, it detected transmural (n = 4) and extralaryngeal spread (n = 1).

Conclusion: Virtual laryngoscopy is a non-invasive technique permits the accurate assessment of the level, extent, degree and cause of subglottic stenosis. So, it provided useful information in the surgical planning of subglottic stenosis.

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