| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||
ABSTRACT |
Zheng W.; Fang W.; Guo Y. Second Hospital, Shantou University, Medical College, Shantou, China
Address correspondence to W. Zheng (hwenb{at}21cn.com)
Objective: To evaluate the motor reorganization and the risk of motor deficit in patients presenting with space-occupying lesions in motor cortex.
Materials and Methods: A total of 23 patients (13 male and 10 female patients; mean age, 47.1 ± 0.6 years; aged 21–53 years) with space-occupying lesions of the central sulcus area, and nine healthy right-handed adults (5 male and 4 female patients; mean age, 34.2 ± 0.3 years; aged 22–51 years) were enrolled in the study. In all patients, surgical treatment for removing the lesion was considered. The tumor types were astrocytoma (8 patients), metastatic tumors (7 patients), meningiomas (5 patients) and arteriovenous malformations (3 patients). Methods: Twenty-three patients and 9 healthy volunteers underwent both conventional and functional magnetic resonance imaging (MRI) examinations. All subjects were examined using a commercial 1.5-T scanner. Patients were divided into two groups. In group A they had severe motor deficit (grade 2–4, n = 11) and in group B they were without motor deficit (grade 5, n = 11). Simple hand movements were examined separately for the right and left hand at a self-paced rate in 20 patients and 9 healthy volunteers. The other 3 patients with severe motor deficit were by passive stimulation. Procedures: Volumes of activation of primary motor area (M1), premotor cortex (PMC) and supplementary motor area (SMA) of both hemispheres in all subjects and the number of patients presented displacement of the activity M1 larger than 10 mm in the affected hemisphere in comparison to the opposite one in group A and group B were measured.
Results: With an alternating hand movement task, 20 patients underwent initiative stimulation and two patients underwent passive stimulation presented activation of primary motor area (M1). The present fMRI study demonstrated the displacement and distortion of the M1 in the space-occupying lesions affected hemisphere were significantly different between group A and group B (p < 0.01). Activation of ipsilateral M1 and premotor cortex (PMC) of both hemispheres were significantly different between patients and controls (p < 0.01). No significant change in the volumes of the SMA in any group, compared with controls (p > 0.05).
Conclusion: BOLD- fMRI is an effective method in localizing motor cortex and it is valuable for the evaluation of the motor deficit in patients.
E356. Application of fMRI–Influence of Difficulty of a Cognitive Task on the Patterns of Brain Activity
Urbanik A.1; Binder M.2; Sobiecka B.1; Kozub J.1 1. Collegium Medicum Department of Radiology, Jagiellonian University - Kraków, Poland; 2. Institute of Psychology–Department of Psychophysiology*, Jagiellonian University - Kraków, Poland
Address correspondence to A. Urbanik (aurbanik{at}mp.pl)
Objective: The aim of the study was to examine the effects of cognitive task difficulty on the patterns of brain activity. We also determined whether the higher level of difficulty affects in the same way task based on verbal and nonverbal material.
Materials and Methods: Twelve volunteers were examined in the Signa Horizon 1.5-T MR (BOLD). Experimental design consisted of four activation runs. Each of them utilized another stimulus and various levels of difficulty. During the first and the second run, subjects were required to remember the changing sequences of letters and the length of the sequences was different for the easy and the difficult task. In the third and the fourth run, subjects were asked to remember changing sequences of abstract pictures; the number of pictures was different depending on the difficulty of the task. Statistical analyses were carried out using SPM99 software.
Results: The most significant increase associated with difficulty was observed in the dorsolateral prefrontal areas, both in verbal and nonverbal tasks. Furthermore, there were separate activation sites for the nonverbal (parietal cortex) and verbal tasks (precentral gyrus, left parietal cortex), not sensitive to the task difficulty.
Conclusion: Areas responsible for various aspects of cognitive function were differently activated by the level of cognitive demand. Regions responsible for manipulation showed increase of activity, which was dependent of the level of difficulty. This was not observed for the areas whose activity was dependent of the type of the task (i.e. storage of verbal and nonverbal material).
E357. Application of FMRI in Hypnotic Suggestion During Pain Stimulation
Urbanik A.2; Aleksandrowicz J.1; Chrzan R.2; Binder M.3; Kozub J.2; Sobiecka B.2 1. Collegium Medicum Department of Psychiatry, Jagiellonian University–Kraków, Poland; 2. Collegium Medicum Department of Radiology, Jagiellonian University–Kraków, Poland; 3. Institute of Psychology–Department of Psychophysiology, Jagiellonian University–Kraków, Poland
Address correspondence to A. Urbanik (aurbanik{at}mp.pl)
Objective: The aim of the study was an assessment of the influence of hypnotic suggestion on the patterns of neural activation during pain stimulation.
Materials and Methods: Twelve volunteers (5 men, 7 women) were examined in a 1.5-T MR scanner. Each subject underwent four subsequent experimental sessions with different conditions applied: (1) pain stimulation (PS), (2) PS and verbal analgesic suggestion (VAS), (3) PS and hypnotic induction (HI), (4) PS, HI and VAS. Nociceptive stimulation was performed by pricking the palmar side of the hand with a sharp piece of wood (avoiding skin puncture). To avoid pain adaptation stimulation was carried in various points within the palmar region. Statistical analysis of the data was done using SPM2 and Mars-BaR software. We assessed global patterns of neural activity as well as differences in the mean signal intensity in the selected ROI's (postcentral and cingulated gyri and insulae), which participate in pain perception.
Results: In all sessions nociceptive stimulation evoked enhanced BOLD responses in postcentral gyrus bilaterally (with stronger activation on the contralateral gyrus), insular regions and cingulate gyri. We did not find any regional differences in the patterns of activation in all four experimental sessions. ROI analysis yielded significant decrease of the signal correlated with the hypnotic suggestion; this effect was strongest in the postcentral gyri and insular cortex.
Conclusion: We have observed that induction of hypnotic state can markedly reduce neural activity within regions responsible for pain perception.
E358. Application of Proton MRS Imaging for Assessment of Metabolic Abnormalities in Cortical Grey Matter, Thalamic Grey Matter and White Matter in Relapsing-remitting Multiple Sclerosis
Urbanik A.1; Szafirska M.1; Herman-Sucharska I.1; Sobiecka B.1; Kozub J.1; Rog T.2; Gryz-Kurek E.2 1. Department of Radiology, Jagiellonian University Medical College, Cracow, Poland, Krakow, Poland; 2. Institute of Neurology, Jagiellonian University Medical College, Cracow, Poland, Krakow, Poland
Address correspondence to A. Urbanik (aurbanik{at}mp.pl)
Objective: In multiple sclerosis, proton MRS can show abnormalities within the lesions. The aim of the study was the assessment of grey matter (cortical and thalamic) and white matter that appears normal on conventional MR imaging, using proton MRS.
Materials and Methods: 45 patients (17–48 years of age, mean 28 years, 32 women, 13 men) with relapsing-remitting multiple sclerosis were examined with the use of 1.5 T GE Signa Excite unit. T2-weighted MR imaging and single voxel spectroscopy (SVS/PRESS) was performed. Absolute N-acetylaspartate (NAA) creatine (Cr), choline (Cho) and myo-inositol (mI) levels were obtained from normal-appearing white matter, cortical grey matter (from frontal region) and thalamic grey matter. Afterwards NAA/Cr, Cho/Cr and mI/Cr ratios were calculated. The results were compared with those of control group.
Results: The results for white matter, cortical grey matter, and thalamic grey matter in patients with relapsing-remitting multiple sclerosis were different from the results of the control group. For the patients the following ratios were found: normal-appearing white matter NAA/Cr=1,87±0,34, Cho/Cr=1,01±0,31, mI/Cr = 0.74 ± 0.35 cortical grey matter NAA/Cr = 1.95 ± 0.45, Cho/Cr = 0.88 ± 0.18, mI/Cr = 0.91 ± 0.24 thalamic grey matter NAA/Cr = 1.94 ± 0.38, Cho/Cr = 0.98 ± 0.2, mI/Cr = 0.92 ± 0.31. In the control group, these ratios were: white matter NAA/Cr = 1.92 ± 0.85, Cho/Cr = 0.86 ± 0.26, mI/Cr = 0.58 ± 0.19 cortical grey matter NAA/Cr = 2.41 ± 0.78, Cho/Cr = 1.22 ± 0.71, mI/Cr = 0.97 ± 0.62 thalamic grey matter NAA/Cr = 2.2 ± 0.51, Cho/Cr = 1.09 ± 0.26, mI/Cr = 0.99 ± 0.3.
Conclusion: The metabolic abnormalities in the patients with relapsing-remitting multiple sclerosis may be detected using proton MRS. The changes are seen not only in lesions in white matter but also in normal-appeared white matter, cortical grey matter and in the thalamus.
E359. Application of fMRI in Estimation of Neural Correlations of Working Memory Activity
Urbanik A.1; Binder M.2; Sobiecka B.1; Kozub J.1 1. Collegium Medicum Department of Radiology, Jagiellonian University–Kraków, Poland; 2. Institute of Psychology–Department of Psychophysiology, Jagiellonian University–Kraków, Poland
Address correspondence to A. Urbanik (aurbanik{at}mp.pl)
Objective: Working memory is considered to be a cognitive system responsible for the temporary storage and manipulation of different kinds of information. The aim of the study was the attempt to answer the question whether there are specialized brain structures that support working memory functions associated with performance of verbal and nonverbal tasks.
Materials and Methods: Twelve neurologically healthy, right-handed volunteers were examined in the Signa 1.5-T MR system (Signa Horizon, GEMS) using BOLD technique. Experimental design consisted of two activation runs. Each of them included different task. During the first run subjects were required to remember the changing sequences of letters, and during the second run they were asked to remember changing sequences of abstract pictures. Statistical analyses were carried out using SPM99 software.
Results: For both verbal and nonverbal task, localization of the several active areas partially overlapped, and the common activated areas were situated in the prefrontal cortex: dorsal-lateral prefrontal cortex bilaterally, ventral-lateral prefrontal cortex in the left hemisphere and the anterior cingulate gyrus. Furthermore, there were separate activation sites for the nonverbal and verbal tasks, which were observed in the left parietal cortex for the verbal task and the frontal cortex for the nonverbal task.
Conclusion: In our study we observed separate areas responsible for different aspects of working memory performance, namely, manipulation (update and monitoring) and storage of information. Regions responsible for manipulation were independent of the task, and localization of regions responsible for storage was associated with the type of stimulus (verbal or nonverbal).
E360. Diagnosis and Characterization of Intracranial Aneurysms with CT-Angiography in Acute Subarachnoid Hemorrhage
Lydell C. P.; Hudon M. E. Diagnostic Radiology, Foothills Medical Centre, University of Calgary, Calgary, Canada
Address correspondence to C. Lydell (carmen.lydell{at}calgaryhealthregion.ca)
Objective: CT angiography (CTA) has been advocated for the detection of aneurysms in patients with nontraumatic subarachnoid hemorrhage; however, performance of this modality in clinical practice has not been critically examined. The purpose of this retrospective review was to: 1) determine utilization of CTA compared to digital subtraction catheter angiography (DSA); 2) calculate efficacy of CT angiography in the diagnosis of all cerebral aneurysms and the clinically relevant aneurysms; 3) identify common sites and characteristics of missed aneurysms.
Materials and Methods: Discharge summaries were searched for patients diagnosed with nontraumatic subarachnoid hemorrhage. Results were initially tabulated over a one year introductory phase (Phase 1), from March 2004-05, when neuroradiologists were gaining experience with CTA and postprocessing techniques. After review of initial Phase 1 results, and common sites of missed aneurysms, results were tabulated for the subsequent 16-month period (Phase 2), from March 2005–July 2006.
Results: During Phase 1, CTA was performed on 38 of 94 patients with nontraumatic subarachnoid hemorrhage. Increasing utilization of CTA was demonstrated over the course of the year. The sensitivity of CTA for detection of all 24 aneurysms was 75% compared to DSA. For detection of the aneurysm of clinical interest, the sensitivity was 96%. Specificity was 100% in both analyses. Phase 2 data revealed a sensitivity of 92% in detecting all 61 aneurysms and 95% in detecting the aneurysm of interest. The specificity was 91% and 95%, respectively. The use of CTA surpassed DSA as the primary diagnostic study. Patients usually proceeded to surgery without confirmatory DSA except when patients were thought to be candidates for endovascular intervention. Common sites of missed aneurysms include the cavernous portion of the internal cerebral artery and at the middle cerebral artery (MCA) bifurcation. The MCA bifurcation was also a common site for false positive results. Most aneurysms missed measured less than 4 mm diameter.
Conclusion: CT angiography is a useful initial investigation in patients with nontraumatic subarachnoid hemorrhage and can expedite diagnosis, characterization and management. With knowledge of common sites of missed aneurysms and increased experience, the sensitivity of CTA may be improved in detecting all aneurysms.
E361. Computed Tomographic Angiography as the Primary Diagnostic Study in Acute Ruptured Cerebral Aneurysms— Correlation with Intraoperative Findings
Patel B.; Mcginn G. Health Sciences Center, Winnipeg, Canada
Address correspondence to B. Patel (bpatel03{at}hotmail.com)
Objective: To evaluate the utility of computed tomographic angiography (CTA) as the primary diagnostic investigation in the detection of ruptured aneurysms in patients with acute subarachnoid hemorrhage (SAH), and to correlate the results with intraoperative findings.
Materials and Methods: A retrospective review of 171 patients undergoing emergent surgical clipping of acutely ruptured intracranial aneurysms between January 2000 and June 2005 was performed. Patients selected were those with acute subarachnoid hemorrhage (SAH) confirmed by noncontrast head CT or by cerebrospinal fluid findings from lumbar puncture. Patients subsequently underwent preoperative three-dimensional CTA as the sole or primary diagnostic study. The results of the CTA were correlated with the intraoperative findings.
Results: CTA correctly detected the ruptured aneurysm in 170 cases when compared to intraoperative findings. Of the 22 cases where CTA demonstrated more than one aneurysm, the predicted ruptured aneurysm was correctly identified every time. In the one case where CTA initially did not demonstrate the ruptured aneurysm, the study was severely degraded with motion artifact. The sensitivity of CTA to detect the ruptured aneurysm in the setting of acute SAH from our data is 99.4% [confidence interval 97.8-99.9%%].
Conclusion: CTA can provide prompt and accurate diagnostic and anatomic information with a 99.4% detection rate in acute ruptured aneurysms. In cases of multiple aneurysms CTA is able to discern the ruptured aneurysm accurately. A positive CTA in the setting of acute spontaneous SAH may be sufficient for intraoperative treatment planning.
E362. Prospective Comparative Study of Two Imaging Protocols in Patients with Acute Stroke
Langer R. D.2; Al Kaabi H.2; Neidl van Gorkom K.2; Czechowski J.1; Torab F.2; Ashish M.1 1. Al Ain Hospital, Al Ain, United Arab Emirates; 2. FMHS/UAE University, Al Ain, United Arab Emirates
Address correspondence to R. Langer (rlanger{at}uaeu.ac.ae)
Objective: To evaluate the detection rate and localization of acute cerebral ischemia in two groups: group 1 (historical group) with unenhanced early cranial computed tomography [CCT], and prospective group 2 with multimodality CCT with perfusion studies and CT angiography (CTA). To compare the results of early CCT in both groups with the definite infarction size/localization on follow up [FU] CCT.
Materials and Methods: Historical group 1: unenhanced CCT of 50 consecutive patients with acute stroke were evaluated retrospectively, using the Alberta Stroke Program Early CT Score [ASPECT], and compared with the definitive infarction size/localization on FU-CCT > 48 h (gold standard). Prospective group 2: 50 consecutive patients underwent multimodality CCT < 6–8 h after clinical onset of symptoms, including perfusion studies: CBF, CBV and MTT as well as CTA. FU-CCT >48 h served again as `gold-standard', modified National Health Stroke Scale (mNIHSS) was used for clinical assessment. The `AAMD Human Research Ethics Committee' approved the research project. The study was supported by the "UAEU Research Office'.
Results: Group 1 included 38 men, 21–92 years old, and 12 women, 41–80 years of age with clinical onset 2–8 h before unenhanced CCT; mNIHSS was 0–28. Group 2 also included 38 men, 27-81 years old, and 12 women, 25-78 years of age. Onset of symptoms was 3–8 h before multimodality CCT; mNIHSS was reported as 0–28. Sensitivity in group 1 was only 58.3%. Detection of small ischemias in the basal ganglia was particularly poor. Multimodality CCT in group 2 showed true positive results in 32 out of 50, false-negative results in 6 out of 50 patients, resulting in a sensitivity of 84.2%. CTA was helpful in selected cases for detection of intracranial stenoses/occlusions, but limited by motion artifacts due to poor patients' compliance. Nine occlusions/stenoses of the intracranial arteries were diagnosed by CTA in the multimodality CCT group.
Conclusion: Multimodality CCT with perfusion studies and CTA is significantly superior to sole unenhanced early CCT for detection of acute cerebral ischemia, and is deemed as a reliable basic diagnostic tool for establishing local stroke units.
E363. The Importance of CT Perfusion in the Management of Patients with Aneurysmal Subarachnoid Hemorrhage for Diagnosis of Vasospasm
Kim S.; Sanelli P. New York Presbyterian Hospital-Weill Cornell University Medical Center, New York, NY
Address correspondence to S. Kim (wonmin_kim{at}yahoo.com)
Background: The leading cause of nontraumatic subarachnoid hemorrhage is rupture of an intracranial aneurysm accounting for 80% of cases [1]. Cerebral vasospasm remains a serious complication, occurring in 40–70% [2, 3], and is the leading cause of morbidity and mortality. Vasospasm continues to be a significant adverse prognostic factor for outcome, resulting in permanent neurologic deficit, stroke and death. Stroke has been detected in up to 81% [4, 5]. Prompt medical treatment can prevent its sequelae [6, 7, 8] and therefore, earlier and more accurate detection of vasospasm is critical. The diagnosis of vasospasm remains challenging due to its complex and poorly understood pathophysiology. The current approach for its diagnosis is to rely on findings from clinical exam, transcranial Doppler ultrasound (TCD) and digital subtraction angiography (DSA). However, there are many shortcomings to using these modalities [9, 10]. Thereby, other imaging modalities need to be explored that can potentially improve diagnostic accuracy of vasospasm. One such modality, CT perfusion (CTP) can provide both qualitative and quantitative information on capillary-level hemodynamic status using parameters of cerebral blood flow, cerebral blood volume and mean transit time.
Key Issues: In this exhibit, a brief description of the technical aspects of CTP will be discussed. The importance of CTP in the management of patients with aneurysmal subarachnoid hemorrhage (A-SAH) for diagnosis of vasospasm and treatment follow-up will be reviewed. Patterns of perfusion imaging in patients with A-SAH will be evaluated at different time-points during hospitalization; specifically at baseline (day 0–3 following A-SAH event), at the most typical time-point for development of vasospasm (day 6–9), and follow-up perfusion imaging (day 12–17). Distinguishing features of perfusion abnormalities associated with development of vasospasm will be presented. Findings on clinical exam, TCD and DSA will be provided with the perfusion imaging. Baseline CTP performed in 100 patients with A-SAH will be correlated with the Hunt-Hess grade, Glasgow coma scale, NIH stroke scale and Fisher class. These findings will also be correlated with patients' clinical outcome.
Format: The format will be didactic and organized by imaging technique.
Teaching Points: 1. To gain familiarity with CTP. 2. To understand the role of CTP in the management of aneurysmal subarachnoid hemorrhage. 3. To recognize perfusion patterns associated with development of vasospasm.
E364. Patients with Acute Intracerebral Hemorrhage: Logical Way to Prioritize the Urgent Digital Subtraction Angiography (DSA) Requests
Pang C. B.2; Wong K.1; Lee R.1; Khong P.2 1. Queen Mary Hospital, Hong Kong; 2. The University of Hong Kong, Hong Kong
Address correspondence to C. Pang (bycpang{at}hkucc.hku.hk)
Objective: To evaluate the efficacy of urgent digital subtraction angiography (DSA) in acute intracerebral hemorrhage and to identify the positive DSA finding rate.
Materials and Methods: All 47 consecutive patients presented with acute intracerebral hemorrhage that underwent urgent DSA in 2004–2005 were included. Patients with known cerebral vascular malformation or cerebral tumor were excluded. The clinical history, CT, DSA and follow-up MR images were reviewed by 3 radiologists. Patient was classified as hypertensive if there was known history and the blood pressure (BP) remained elevated at 3-month follow-up. The site of the intracerebral hemorrhage was evaluated. The presence of associated subarachnoid hemorrhage (SAH) or intraventricular hemorrhage (IVH) was recorded. Favorable outcome at 6-month follow up was defined as modified Rankin score (mRs) of <2.
Results: 4 patients required emergency craniotomy and clot evacuation with only postoperative DSA performed were excluded. The mean age of the remaining 43 patients (M:F = 19:24) was 47.2. Positive DSA findings were obtained in 17 patients (39%). The DSA positive rate is 42% for patients <40 years old and 38% for those >40 years old. All aneurysms (n = 4) were detected in patients >40 years old. 90% (18/20) of patients with hypertension have negative DSA findings (p < 0.001). All patients with hypertension and basal ganglia (n = 7) hemorrhage have negative DSA findings. 86% of them (6/7) have unfavorable outcome at 6 months. 83% (5/6) of patients with associated SAH have positive DSA findings (p = 0.028). No significant correlation is seen between positive DSA findings and the presence of IVH, hematoma volume and the presenting GCS. Logistic regression shows no correlation between DSA findings and the age of the patients (p = 0.759, 95% CI 0.961–1.057).
Conclusion: Positive DSA findings are more common in patients with acute intracerebral hemorrhage with concomitant SAH. 90% of the hypertensive patients have negative DSA findings, particular in the subcategory of basal ganglion hemorrhage. Aneurysm is more likely to be seen in patients >40 years old.
E365. Brain Magnetic Resonance Imaging Findings in Young Patients with Hepatosplenic Schistosomiasis Mansoni, without Neurological Symptoms
Manzella A.; Oliveira K. F.; Brandt C. T.; Borba FilhoP.; Holanda G. Hospital das Clinicas da Universidade Federal de Pernambuco, Recife, Brazil
Address correspondence to A. Manzella (adonismanzella{at}yahoo.com.br)
Objective: Far less commonly, schistosomes reach the central nervous system (CNS). This may occur with any of the clinical forms of schistosomal infection. Most of the cases of CNS involvement associated with the hepatosplenic and cardiopulmonary chronic forms, or with the severe urinary schistosomiasis, though more frequent, are asymptomatic. The purpose of this study was to describe the brain magnetic resonance imaging (MRI) findings in young patients with hepatosplenic schistosomiasis mansoni, without evidence of neurological manifestations.
Materials and Methods: Thirty-four young individuals, ranging in age from 9 to 25 years, were randomly selected among a population of patients with hepatosplenic schistosomiasis mansoni who had undergone splenectomy, ligature of the left gastric vein and auto implantation of spleen tissue. Patients were scanned on a 1.5-T system. Multiplanar T2-weighted, T1-weighted and FLAIR images were obtained before and after paramagnetic contrast administration and the reports were done by two radiologists after a consensus review.
Results: The MR exams were normal in 9 patients (26.5%). Twenty-five patients (73.5%) presented MR signal abnormalities. Twelve (48%) of the 25 patients presented small increased signal intensities on T2-weighted images in the cerebral white matter. Symmetric hyperintense globus pallidus and/or cerebral peduncle on T1-weighted images were seen in 8 (32.0%). Discrete T2-weighted hyperintense peritrigonal areas were noted in 5 (20.0%) of the 25 patients, interpreted as incomplete brain myelination.
Conclusion: Symmetric hyperintense globus pallidus on T1-weighted cranial MRI is often seen in patients with hepatic encephalopathy but generally not in the absence of neurological abnormalities. Some of these findings, although not specific, are not usually seen in healthy young individuals, indicating that there may be a relationship between these abnormalities and schistosomiasis. From these results one can speculate that brain involvement might be more frequent than it is believed, and seems to follow the pattern seen in patients with cirrhosis. They also emphasize the need for follow-up in these patients with hepatosplenic schistosomiasis mansoni and demonstrate the impact of MRI in research as well as routine medical practice.
E366. Utility of Dynamic Contrast MRA as Part of a Routine Brain MRI with Contrast
Zou Z. The Department of Radiology at People's Liberation Army General Hospital, Beijing, China
Address correspondence to Z. Zou (lancy5672004{at}gmail.com)
Objective: Post gadolinium (Gd) imaging is routinely performed with brain MRI to identify sites where disease causes blood brain barrier breakdown. In this study, time-resolved imaging during Gd injection was added to our routine brain MRI protocol to see if dynamic contrast enhancement data contributes additional diagnostically useful information.
Materials and Methods: 70 patients undergoing routine brain MRI at
3.0 T (n = 20) or 1.5 T (n = 50) were imaged using 3D-TRICKS
during injection of 0.1 mMol/kg Gd at 3 ml/s. Imaging was performed in the
sagittal plane using an 8-channel phased array coil and the following
parameters: TR/TE/flip angle 
3.5/1.2/35, bandwidth = 100kHz, FOV = 26cm,
matrix = 320 x 192 with 2.4mm slice thickness zero-filled down to 1.2mm
intervals. Temporal resolution was 3 to 4s per phase depending upon the number
of slices. Enhancement kinetics was assessed with region of interest analysis
and vasculature was evaluated on MIPs and source images.
Results: Mean time to peak (tp) carotid, MCA, superior sagittal sinus and jugular enhancement were 19.0, 19.4, 25.7 and 26.4 seconds. A pure arterial phase was attained in every patient; no significant occlusive disease was noted but one unexpected aneurysm was identified at the internal carotid artery bifurcation which was not seen on the other MR sequences. Anomalies of venous drainage with hypoplastic transverse sinus on the left in 9 patients and on the right in 2 patients which were potentially significant in these two patients undergoing brain tumor surgery. Contrast kinetic measurements showed rapid enhancement in ependymoma (tp = 22s), three glioblastomas (tp = 38s), five meningiomas (tp = 35s), three lymphomas (tp= 55) and 1 pediatric astrocytoma (tp = 17s). All the other astrocytomas (n = 2) and gliomas (n = 8), enhanced too slowly to visualize on time-resolved MRA. A carcinoid metastasis enhanced rapidly (tp = 17s) but adenocarcinoma metastases enhanced very slowly (tp =80s). Since all patients were being injected with Gd to obtain delayed images, there was no extra contrast agent cost; however, the complexity of injecting during imaging added an additional 5 to 10 minutes to the examination time. SNR was higher at 3.0 T compared to 1.5 T in carotid artery (13.5 vs 7.1 p = 0.03) and jugular vein (18.7 vs 11.9 p = 0.03).
Conclusion: Imaging dynamically during contrast agent injection adds information about vasculature and tumor enhancement kinetics which may be helpful in assessing patients with neurological diseases and making better plans for surgery.
E367. Volumetric MRI Versus Standard 3-plane MRI in Detection of Brain Metastases
Partin R.; Lu S.; Kelly T.; Sadeghian R. Monmouth Medical Center, Long Branch, NJ
Address correspondence to R. Partin (richusf{at}yahoo.com)
Objective: In patients with metastatic disease to the brain, evaluation of the number and location of lesions is important for therapeutic planning. Postgadolinium volumetric T1-weighted MR imaging yields images of higher resolution and no skip as compared with standard post-gadolinium T1-weighted imaging performed in three planes. Therefore, we hypothesize that adding volumetric MR imaging to the standard MR protocol for metastatic workup will improve the accuracy of the identification of metastatic lesions.
Materials and Methods: The study population consisted of 10 patients presenting for brain MR to evaluate for metastatic disease of the brain. Patients were included if standard 3-plane post-gadolinium MR and volumetric postgadolinium MR performed concurrently demonstrated enhancing lesions. Retrospectively, two attending neuroradiologists independently interpreted both the standard 3-plane and the volumetric MR images. Enhancing parenchymal lesions were identified and categorized as definite or questionable. Statistical analysis was performed comparing standard 3-plane to volumetric MR for differences in lesion detectability. The number of definite lesions, num-ber of questionable lesions, number of total lesions, and questionable lesions as a percentage of total lesions were compared using a student's T-test.
Results: Analysis of the number of definite lesions and analysis of the number of total lesions demonstrated no significant difference between the two techniques. There was a trend toward a decrease in the number of questionable lesions; however, this decrease did not achieve statistical significance (p = 0.15). Comparison of questionable lesions as a percentage of total lesions yielded a significantly lower percentage with volumetric versus standard imaging (p < 0.05).
Conclusion: While this study does not indicate an increased sensitivity for metastatic brain lesion detection with volumetric versus standard MR imaging, it does indicate a reduction of questionable lesions as a percentage of total lesions. These questionable lesions can significantly alter treatment decisions. For example, surgery may be eschewed if there are more than three lesions, and radiation therapy may otherwise target false positive lesions. A potentially useful benefit has been identified in adding volumetric imaging to the standard protocol for the brain metastatic workup. Additional research may be of benefit to determine whether this justifies the addition of this technique on a routine basis.
E368. Neuroimaging Footprints of Gamma Knife Radiosurgery: Radiation Necrosis vs Gliosis vs Recurrent Disease vs Radiationinduced de Novo Lesion
Sidhu H. S.; Amankulor N. M.; Chiang V. L.; Johnson M. H. Yale University School of Medicine, New Haven, Connecticut
Address correspondence to H. Sidhu (harmansidhu{at}dr.com)
Background: The use of radiation therapy has become a mainstay in the minimally invasive treatment of a variety of cerebral pathologies both as primary and/or adjunctive therapeutic options. Significant considerations to treatment with radiation relate to the potential for side effects as they relate to damage to nontarget tissue via radiation necrosis, the potential for incomplete treatment tumor recurrence, and the possibility for the development of de novo lesions. With the development of stereotactic radiotherapy, specifically gamma knife radiosurgery, the amount of nontarget tissue damage has been significantly reduced. However, the long term follow-up of such patients with regard to potential complications relating to radiation necrosis, incomplete treatment tumor recurrence, and the development of de novo lesions is limited to case series of treatment of specific disease processes.
Key Issues: A brief review relating to the principles of stereotactic radiosurgery with the gamma knife unit will be conducted along with a limited review of radiation biology as it pertains to the treatment of a variety of disease processes. Through the review of the Yale New Haven Hospital Gamma Knife Patient Database, common MRI findings in post therapy patients will be reviewed and illustrated. These findings include radiation necrosis, residual tumor, and the development of de novo lesions including new tumors and cavernous malformations. Additionally, principles for distinguishing different post therapeutic entities with overlapping imaging findings will be discussed and illustrated using MRI, PET, and nuclear medicine imaging modalities.
Format: A PowerPoint based didactic session will be conducted followed by a short self-assessment module at the end of the presentation.
Teaching Points: Teaching points include a basic understanding of stereotactic radiosurgical (gamma knife) techniques, radiation biology as it pertains to the treatment of cerebral pathologies including malignancy, vascular malformations, and functional ablations (trigeminal neuralgia). Common presenting signs and symptoms are correlated with regard to imaging findings and time course following therapy. Additionally, methods for distinguishing different post therapeutic entities with overlapping imaging findings are described.
E369. Postgadolinium T1 Perfusion Imaging: The MR Perfusion Sequence of Choice for Evaluation of Treatment Response in Patients with Primary Brain Neoplasms
Fleming K. W.2; Hou B.1; Holodny A.1 1. Cornell University Memorial Sloan-Kettering Cancer Center, New York, NY; 2. Cornell University New York Presbyterian Hospital, New York, NY
Address correspondence to K. Fleming (keithwfleming{at}gmail.com)
Background: Since the advent of angiogenesis inhibition therapy with bevacizumab (Avastin), characterization of brain tumor perfusion has direct clinical application for determining response to therapy. T2* perfusion software packages are commercially available, and T2* perfusion has been the traditional MR perfusion imaging sequence used for evaluation of primary brain neoplasms. While there are no postgadolinium T1 perfusion imaging software packages currently commercially available, in our experience T1 perfusion imaging is more sensitive to changes in tumor vascularity and capillary integrity than T2* perfusion.
Key Issues: The exhibit will demonstrate the increased sensitivity of T1 postgadolinium perfusion to changes in tumor vascularity and capillary integrity in patients on Avastin therapy. The exhibit will demonstrate findings from several patients from our institution who have undergone T1 postgadolinium and T2* perfusion imaging both before and after Avastin therapy. In our experience, both T2* and postgadolinium T1 techniques demonstrate decreased vascularity in post therapy patients. However, T1 postgadolinium perfusion imaging better demonstrates the decrease in capillary permeability that occurs in patients who respond to Avastin therapy.
Format: The format of the exhibit will be didactic. The first part of the exhibit will briefly discuss common indications for MR perfusion imaging, including assessment of response to angiogenesis inhibition. The mechanism of action of Avastin will be explained. The second part will be a series of cases. Each case will be introduced by displaying conventional MR images, followed by the T2* and T1 post-gadolinium perfusion images. Arrows and text will illustrate the findings, focusing on the differences between the T2* and T1 postgadolinium perfusion images. The third part of the exhibit will describe the scanning technique used to collect the perfusion data, as well as the postprocessing technique used to reconstruct the perfusion data for T1 postgadolinium and T2* image generation.
Teaching Points: The viewer will learn some of the indications for MR perfusion imaging. The viewer will become more comfortable interpreting perfusion images. The viewer will learn the differences between T1 postgadolinium and T2* perfusion techniques and imaging findings in patients on Avastin therapy. The viewer will gain a deeper understanding of the acquisition of perfusion data and the postprocessing required to generate perfusion images.
E370. Dynamic Susceptibility-weighted Contrast-enhanced (DSC) Perfusion MRI in Neurooncological Imaging
Mangla R.; Srinath G.; Kathuria S.; Ekholm S.; Westesson P. University of Rochester Medical Centre, Rochester, NY
Address correspondence to R. Mangla (Rajiv_Mangla{at}urmc.rochester.edu)
Background: DSC MR imaging is a robust and most widely used technique amongst various methods of perfusion imaging. It plays a pivotal role in the transition from a purely morphology based discipline to one that combines anatomy with physiology. When used in the study of mass lesions of the brain, it helps to distinguish between tumor and tumor mimicking lesions. It helps in the differentiation and categorization of tumor grade. The DSC MR imaging depicts regional variations in microvasculature, thus distinguishing between normal and diseased brain tissue without obvious abnormality on routine MR sequences.
Key Issues: This exhibit briefly describes the physical basics of DSC MR imaging and summarizes its present clinical use in the evaluation of brain tumors. A) Imaging technique–The first-pass of a contrast bolus in brain tissue is monitored by a series of T2*-weighted MR acquisitions. The susceptibility effect of the paramagnetic contrast agent leads to a signal loss that can be converted, using the principles of the indicator dilution theory, into a contrast agent concentration curve. The area under the curve for each voxel is mathematically integrated, similar to standard tracer experiments used to calculate CBV. Creating CBF maps involves an additional arterial input function and MTT maps are then created by dividing CBV/CBF. The blood brain barrier permeability maps are also created using the initial data. B) Imaging findings-This exhibit will discuss the role of perfusion in: 1. Grading of gliomas. 2. Differentiaton between tumor and tumor mimicking brain lesions. 3. Distinguish between tumor recurrence, radiation necrosis and peritumoral edema.
Format: Format–didactic presentation. Organizational structure–Description of technique, pictorial imaging findings with illustration in application of DSC in brain tumors and other neuropathological conditions which mimic tumors with pathological correlation.
Teaching Points: DSC MR imaging is: 1. Useful in the preoperative work-up of various neoplasms, as well as in the differentiation of neoplastic lesions from infections and other tumor-like conditions. 2. A tool to measures tumor angiogenesis and capillary permeability, which are important biological markers of malignancy grade and prognosis, particularly in gliomas. 3. Helpful in determining regions of active tumor growth, used as the target of stereotactic biopsy. 4. Useful tool to detect residual tumor, treatment response and therapyrelated complications such as radiation necrosis.
E371. Neuro-Behcet's Disease: A Review
Radwan S. M. Theodor Bilharz Research Institute, Giza, Egypt
Address correspondence to S. Radwan (shradwan{at}hotmail.com)
Background: Behcet's disease (BD) is a multi-system disorder of unknown etiology. It frequently involves the nervous system, in which case it is referred to as Neuro-Behcet's disease (NBD). The neurological manifestations in BD are classified into two groups: the primary neural parenchymal group and secondary nonparenchymal group. The purpose of this article is to recognize the MRI findings in NBD and to differentiate between it and other disorders, such as systemic lupus erythematosus (SLE) and multiple sclerosis (MS).
Key Issues: 1) To learn the epidemiology, clinical manifestations, course, etiology and pathogenesis of Neuro-Behcet's disease (NBD). 2) To illustrate the various imaging findings in NBD. 3) To demonstrate unusual imaging findings on MRI including diffusion MR and proton MR spectroscopy (MRS). 4) To learn the differential diagnosis of Neuro-Behcet's disease and the conditions that may mimic it.
Format: –epidemiology of NBD. –etiology and pathogenesis of NBD –Clinical presentations, course of the disease. –MRI imaging findings of NBD: –conventional MRI –Diffusion weighted MR imaging –Proton MRS. –sample cases and differential diagnosis.
Teaching Points: The major teaching points of this exhibit are: 1) In the acute phase of NBD, large confluent lesions in the brainstem-thalamic-basal ganglia region can help to differentiate it from MS and SLE. 2) In SLE, the lesions predominantly involve the sub-cortical white matter of the cerebral hemispheres and less frequently involve the basal ganglia or brainstem 3) In MS, the lesions are predominantly periventricular, with infrequent involvement of the basal ganglia and internal capsule 4) Dural sinus thrombosis is the most frequent vascular manifestation of NBD 5) MRS can be used for early detection of brain involvement as well as for follow-up of MRI-negative NBD.
E372. Feasibility of Superficial Temporal Artery as Input Artery in Cerebral Perfusion CT
Sheikh K.; Schipper M. J.; Hoeffner E. G. University of Michigan Medical School, Ann Arbor, MI
Address correspondence to K. Sheikh (sheikhk{at}med.umich.edu)
Objective: Perfusion computed tomography (PCT) allows the generation of quantitative maps of cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT). This technique requires the user to select input variables, including an arterial input function. It has been suggested that a diseased vessel should not be used as the arterial input; however, this may be problematic if the diseased vessel is not known or if there is multifocal disease. This study was designed to determine if the superficial temporal artery (STA) as input artery can generate accurate perfusion maps, with significant correlates for CBF, CBV, and MTT compared to anterior cerebral artery (ACA) as the input artery.
Materials and Methods: One hundred perfusion CT exams performed on 90 patients (51 women, 39 men) were retrospectively reviewed and postprocessed by one investigator at an Advantage Windows workstation using CT perfusion software (GE Medical Systems). From the existing perfusion CT examinations, color-coded CBF, CBV, and MTT maps were constructed. Values were derived by varying the input artery (e.g., STA versus ACA), and the effect on the mean CBF, CBV, and MTT values in 6 ROI (1 ROI in each ACA, MCA and PCA territory) were calculated.
Results: All graphs of correlation between ACA and STA input arteries produced significant results with p < 0.0001. There was excellent correlation between ACA and STA in CBF values (Pearson correlation coefficient of 0.96; concordance correlation coefficient of 0.96), in CBV values (Pearson correlation coefficient of 0.97; concordance correlation coefficient of 0.97) and in MTT values (Pearson correlation coefficient of 0.97; concordance correlation coefficient of 0.97). Linear regression lines produced strong agreement between ACA and STA [CBF (y = 1.03x + 0.65); CBV (y = 1.05x – 0.09); MTT (y = 0.92x + 0.21)].
Conclusion: Preliminary results demonstrate that using extracranial vessels (e.g., superficial temporal artery) as the input artery can generate comparable perfusion maps to intracranial vessels (e.g., anterior cerebral artery). This can be useful if the proximal intracranial vessels typically used for the arterial input are diffusely diseased (such as with diffuse vasospasm or atherosclerosis) or not included in the FOV for the perfusion CT.
E373. MR Imaging of a Postmortem Formalin-fixed Human Brain of a Multiple Sclerosis Patient at 3.0 T and 7.0 T
Sammet S.3; Kangarlu A.1; Bourekas E.3; Rammohan K. W.2; Koch R. M.3; Knopp M. V.3 1. Columbia University, Brain Imaging Laboratory, New York, NY; 2. The Ohio State University, Department of Neurology, Columbus, OH; 3. The Ohio State University, Department of Radiology, Columbus, OH
Address correspondence to S. Sammet (sammet.5{at}osu.edu)
Objective: Multiple sclerosis (MS) is a chronic, inflammatory and demyelinating disease of the central nervous system. Magnetic resonance imaging (MRI) of the brain and spine is used for diagnosis and monitoring of MS. The purpose of this study was to compare high resolution MRI of MS lesions of a postmortem formalin-fixed brain of a multiple sclerosis patient at 3.0 T and at 7.0 T.
Materials and Methods: Postmortem formalin-fixed brain slices from a MS patient were examined for cortical pathology using a 3.0-T and a 7.0-T whole body MR scanner. The brain slices in saline were placed in 3.0-T and 7.0-T transmit/receive head coils to acquire the images. Coronal spin-echo (parameters: TR = 750 ms, TE = 30 ms, slice thickness = 1.5 mm, FOV = 15cm x 15cm, matrix = 1024 x 1024, NEX = 5) and gradient-echo images (parameters: TR = 750 ms, TE = 7 ms, flip angle = 80, slice thickness = 1.5 mm, FOV = 15 cm x 15 cm, matrix = 512 x 512, NEX = 20) were acquired. All slices were examined by standard H&E staining as well as stains with luxol-fast-blue PAS to confirm the pathology.
Results: Ultra-high-field MRI is capable of detecting MS lesions. Lesions were easily identified using gradient echo and spin echo images. Numerous MS lesions not seen by MR imaging at 3.0 T were evident using MR imaging at 7.0 T.
Conclusion: The greater sensitivity for multiple sclerosis lesions of 7.0-T MRI compared to 3.0 T can lead to a detection of lesions in earlier stages of the disease. Early diagnosis of MS with ultra-high-field MRI and treatment can delay disease conversion. This may lead to an improved monitoring of neurological deficits in MS.
E374. Roads Less Traveled: The Collateral Circulation
Mirsky D. M.; Bello J. A. Montefi ore Medical Center, Bronx, NY
Address correspondence to D. Mirsky (mirsky{at}gmail.com)
Background: With the advent of CT and MR angiography, catheter angiography has assumed a lesser role in the evaluation of neurovascular disease. Knowledge of basic vascular anatomy has survived this sea change. While the role of the collateral circulations remains critical to the interpretation of physiologic imaging, the detailed anatomy of these important pathways escapes many residents in training. In part, this is related to the fact that CTA-MRA are performed more frequently, but do not visualize distal vessels as well as catheter angiography. In addition, CTA-MRA lack the temporal resolution of catheter angiography, which better demonstrates directional flow sequentially. In fact, the collateral circulation plays a pivotal role in the pathophysiology of acute cerebral ischemia. In practice, advanced physiologic imaging stratifies acute stroke patients for intervention dependant on the presence of viable penumbra, which is due to collaterals.
Key Issues: This exhibit integrates the neurovascular anatomy across different imaging modalities and defines and illustrates the various collateral circulations through case material.
Format: The importance of collateral circulations will be demonstrated in a variety of clinical settings, including congenital vascular variants, acquired intra and/or extracranial stenosis or occlusion, and ischemia due to steal phenomenon in vascular malformations. Pathology due to collaterals will also be addressed (i.e., `collateral damage') including COW aneurysms, reperfusion injury, and inadvertent embolization. Our interactive exhibit will provide the participant with a "hands-on" opportunity to avoid adverse outcomes by designing appropriate collaterals for test cases presented.
Teaching Points: Our educational goal is to: a) Define the different collateral circulations. b) Describe their importance in various clinical settings. c) Emphasize their relevance to advanced imaging techniques. d) Consider their role in the understanding of CNS pathophysiology, as well as their pertinence to the development of treatment algorithms for neurovascular disease processes.
E375. An fMRI Study of the Neural Correlates of the Autonomic Cardiovascular Activity
Urbanik A.1; Binder M.2; Sobiecka B.1; Kozub J.1 1. Department of Radiology, Collegium Medicum Jagiellonian University, Kraków, Poland; 2. Institute of Psychology - Department of Psychophysiology, Jagiellonian University, Kraków, Poland
Address correspondence to A. Urbanik (aurbanik{at}mp.pl)
Objective: The aim of this study was assessment of the cerebral centers responsible for the control of the cardiovascular arousal.
Materials and Methods: Twelve volunteers were examined using the Signa Horizon 1.5-T MR (BOLD). Experimental design consisted of two activation runs. During the first run subjects were required to remember the changing sequences of letters, and during the second run they were asked to remember changing sequences of abstract pictures. Subsequently, outside MR scanner, subjects underwent the same procedure with heart rate measurement. Statistical analyses were carried out using SPM99 software.
Results: The experimental task evoked significant changes in heart rate. Imposing more demand on cognitive system resulted in the heightened heart rate values in all subjects. An fMRI analysis revealed significant increases mostly in the left prefrontal areas and in the anterior cingulate gyrus. Neural activity in dorsolateral cortex, insula, anterior cingulate gyrus, as well as hypothalamus and posterior cortex, demonstrated correlation with heart rate changes.
Conclusion: Our results provide an insight to the functional anatomy of brain areas involved in the regulation of autonomic arousal in humans. They suggest that higher cortical centers, such as prefrontal cortex, apart of being involved in complex cognitive tasks, also participate in controlling the level of cardiovascular activity.
E376. Central Nervous System Infection Pictorial Review
Kanekar S.1; Pennypacker J.1; Netland E.1; Boddupalli K.2 1. Penn State Milton Hershey Medical Center and College of Medicine, Hershey, PA; 2. Royal Hobart Hospital, Hobart, Tasmania
Address correspondence to S. Kanekar (san17kan{at}yahoo.com)
Background: The central nervous system (CNS) may be infected by a variety of agents, including viruses, bacteria, fungi, protozoa and other parasites. In addition, a number of noninfectious etiologies may account for syndromes that mimic CNS infections. The clinical presentation of a CNS infection may be acute, subacute or chronic and depends upon the virulence of the infecting agent, immunity of the host and the location of the infection. Because CNS infections occur within the confines of the cranium or spinal column, they may be associated with significant morbidity and mortality, other necessitating emergent interventions to improve outcome.
Key Issues: We reviewed imaging studies of 319 patients from our archive system, which were clinical and laboratory diagnosed as CNS infections. For the purpose of this exhibit and better understanding of etiopathogenesis we classified this presentation into: 1) Congenital/neonatal infections-TORCH infections, congenital HIV. 2) Meningitis-acute (pyogenic/ lymphocytic), chronic. 3) Pyogenic parenchymal infections. 4) Viral parenchymal infections/ encephalitis. 5) Granulomatous and fungal infection. 6) Parasitic infection. 7) Infections in HIV. We illustrate the typical and atypical imaging features of these various infections with diagnostic pearls to their diagnosis.
Format: Our presentation will be didactic electronic exhibit in the format of a pictorial assay, illustrating the imaging features of various CNS infections.
Teaching Points: 1) We present a comprehensive illustrated review of CNS infection. 2) Salient features of some of the infections are highlighted which help in early diagnosis. "Early diagnosis and treatment of CNS infections has the best clinical outcome."
E377. Magnetic Resonance Imaging of Progressive Multifocal Leukoencephalopathy in HIV-Positive Patients
Al Azri F. H.; Pangupath S.; Nguyen T.; Lum C.; Miller W.; Kingstone M.; Wolfe J.; Jansen G. University of Ottawa, Ottawa, Canada
Address correspondence to F. Al Azri (falazri{at}gmail.com)
Objective: To describe the radiological features of progressive multifocal leukoencephalopathy (PML) in HIV positive patients with an emphasis on diffusion-weighted imaging (DWI), perfusion-weighted imaging (PWI) and MR spectroscopy.
Materials and Methods: We retrospectively reviewed a series of 6 patients with a pathologically proven diagnosis of PML. CT and conventional MRI images with contrast were obtained in all patients. MR perfusion (TE = 47, TR = 1320, EPI, 0.1 mmol/kg, Gadovist) and MR proton spectroscopy (2D CSI, TE = 135 and TE = 270) was performed in 2 patients.
Results: All six patients had a presumed diagnosis of PML following the initial CT and MRI examinations. Lumbar puncture was performed in three patients, which was positive for JC virus. On CT, all the patients demonstrated nonenhancing hypodense white matter lesions without significant mass effect. On MRI the lesions appear hypointense on T1 and hyperintense on T2-weighted images. Grey matter and posterior fossa involvement was seen in 2 patients with progression of the disease. On DWI, the lesions appear heterogeneous with a typical area of restricted diffusion at the periphery of the lesions, which also have an increase in cerebral blood volume on PWI. There was increased choline (Cho) peak with decreased N acetyl aspartate (NAA) peak with presence of lactate at the margin of the lesion.
Conclusion: White matter lesions seen in PML appear heterogeneous on MRI, which suggests areas of active and chronic demyelination. This appearance can be further characterized with DWI, PWI and MR spectroscopy. In the appropriate clinical setting, a diagnosis of PML can be made with radiological findings and CSF evaluation for JC virus, avoiding the need for a biopsy.
E378. Spectrum of CNS Imaging Findings in Patients with HIV Infection
Malhotra A.; Srinath G.; Ekholm S. University of Rochester Medical Center, Rochester, NY
Address correspondence to A. Malhotra (ajay_malhotra{at}urmc.rochester.edu)
Background: AIDS continues to be one of the most important causes of morbidity and mortality, CNS involvement being a dominant cause. While neurological symptoms account for only about 10% of initial presentations of AIDS, neurological complications develop in 40–60% of patients. Autopsy results indicate an even higher rate of CNS involvement (73–87%). There is a wide spectrum of CNS disease in AIDS with a) primary HIV effects, b) opportunistic infections, c) neoplastic disease, d) vascular disease. By evolving a systematic approach, the exhibit should help familiarize practicing radiologists with the possible imaging findings and aid in accurate diagnosis.
Key Issues: This exhibit is based on a retrospective analysis of imaging findings in HIV patients with CNS involvement. There is considerable overlap of imaging features between the different diseases affecting CNS in these patients. Therefore, an attempt is made to categorize the various patterns of CNS involvement in AIDS patients and highlight the main differential diagnoses for each imaging pattern.
Format: The following major patterns of CNS involvement will be discussed– 1. Diffuse white matter disease. 2. Patchy white matter disease 3. Focal enhancing mass lesions. 4. Focal nonenhancing mass lesions. 5. Focal enhancing lesions with no significant mass effect. 6. Focal nonenhancing lesions with no mass effect. 7. Meningeal/ Ependymal involvement 8. Cerebrovascular disease 9. Spine involvement. CT and MRI imaging of these patterns will be discussed with clinical and pathological correlation.
Teaching Points: 1. Appreciate the spectrum of diseases affecting the CNS in patients with HIV 2. Develop a systematic approach to differential diagnosis based on imaging patterns
E379. Diffusion-weighted MRI (DWI) and Proton MR Spectroscopy in the Evaluation of Axonal Injury: Correlation with Clinical Outcome after Traumatic Brain Injury
Zheng W.; Fang W.; Wu R. Second Hospital, Shantou University, Medical College, Shantou, China
Address correspondence to w. Zheng (HWENB{at}21CN.COM)
Objective: To evaluated the utility of diffusion-weighted MRI (DWI) and proton MR spectroscopy in identifying patients with neuronal injury after TBI.
Materials and Methods: Twenty-three patients with diffuse axonal injury, aged 17–51 years old; mean age, 27 years; admission Glasgow Coma Scale scores 3–14, mean score 10, were studied on a 1.5-T system with diffusion-weighted MRI (DWI) imaging and MR spectroscopy of the splenium. Scans were obtained 2 hours to 21 days after injury (median, 11 days). Diffusion-weighted imaging (DWI) was performed using spin-echo echo-planar sequence. Apparent diffusion coefficient maps were obtained and the mean ADC values of the posterior commissure of the corpus callosum were measured. Proton MR spectroscopy was used to calculate the N-acetylaspartate (NAA)/creatine (Cr) ratio of the splenium. ADC values and NAA/creatine (Cr) in the splenium in patients were compared with normal control volunteers.
Results: Compared with normal control volunteers, decreased ADC values were identified in 17 patients and decreased NAA/Cr radios were identified in 19 patients in the posterior commissure of the corpus callosum. ADC value in splenium were correlate with GCS (p < 0.001, r = 0.63) and coma duration of the patients (p < 0.001, r = 0.67). In 7 patients with a GCS of 3 to 8, the mean NAA/Cr was 1.23 ± 0.27; In 16 patients with a GCS of 9–14, the mean NAA/Cr was 1.83 ± 0.31 (p < 0.05); NAA/Cr ratios were lower in the group of patients who remained in a persistent coma state than in the group of patients who regained awareness after being in the coma state (p < 0.001).
Conclusion: DWI and MR spectroscopy can quantify damage after TBI, ADC values in splenium correlated significantly with length of coma duration (as a possible surrogate marker for short-term outcome). ADC value and NAA/Cr in splenium may be a sensitive indicator of the neuronal damage that results in a worse clinical outcome.
E380. Diffusion Tensor Imaging and Fiber Tracking in Wallerian Degeneration
Kathuria S.; Liu X.; Ekholm S.; Westesson P. University of Rochester, Rochester, NY
Address correspondence to S. Kathuria (sudhirkathuria{at}yahoo.com)
Objective: Wallerian degeneration is the process of progressive demyelination and disintegration of the distal axonal segment following neuronal damage due to cerebral infarction, hemorrhage, trauma, necrosis, focal demyelination, and is associated with poor neurologic outcome. Recent studies have shown a promising role of DWI and DTI in the early depiction of this injury, when conventional MR imaging may show normal findings. The aim of this exhibit is to discuss the pathophysiology of various stages and the role of new imaging techniques in early depiction of Wallerian degeneration that may signify poor clinical outcome.
Materials and Methods: Case studies from the last several years at our institution of normal anatomy and changes related to Wallerian degeneration of white matter tracts on imaging will be reviewed. Special emphasis will be given to the role of newer techniques, including conventional diffusion-weighted imaging, diffusion tensor imaging and 3D fiber tractography. A review of the current literature will be cross referenced with cases from our institution.
Results: The exhibit will include imaging findings of normal white matter tracts and various stages of Wallerian degeneration on both conventional and newer imaging techniques, including DWI, and DTI with FA maps and 3D fiber tractography.
Conclusion: The newer imaging techniques of DWI and DTI are more sensitive in diagnosing early stages of Wallerian degeneration which may follow various causes of neuronal damage, including infarction, hemorrhage and trauma. Further information about the orientation of these tracts can be obtained using 3D tractography.
E381. Role of Magnetic Resonance (MR) Perfusion in Moyamoya Syndrome
Srinath G.; Mangla R.; Malhotra A.; Ekholm S.; Westesson P. University of Rochester, Rochester, NY
Address correspondence to G. Srinath (guruprasad_srinath{at}urmc.rochester.edu)
Background: Moyamoya syndrome is an angiographically defined cerebral vascular disorder with occlusion of the terminal internal carotid artery and developmental of extensive collateral vessels (puff of smoke). Moyamoya disease is idiopathic or may occur secondary to other conditions. Digital subtraction angiography is the main stay in diagnosis; however, investigators and clinicians have also used positron emission tomography (PET) and single photon emission computer tomography (SPECT) to assess the perfusion. These techniques have limitations such as the use of radiation and limited accessibility and relatively low special resolution. We have used MR perfusion to study hemodynamics changes of Moyamoya syndrome. This educational exhibit will demonstrate the use of MR perfusion in Moyamoya syndrome.
Key Issues: Method–The MR examinations were conducted by using a 1.5-T system with a quadrature head coil. Perfusion-weighted, dynamic susceptibility contrast MR imaging was performed by using a single-shot gradient-echo echo-planar imaging sequence during an intravenous bolus injection of gadolinium based contrast. For each pixel, the time-concentration or R2* curve was obtained, which was calculated from the equation R2*(t) = [ln(SI0/SI(t))], where SI0 is the average precontrast signal intensity and SI(t) is the signal intensity at time t. The cerebral blood flow (CBF) ratio, cerebral blood volume (CBV) ratio, and mean transit time (MTT) were calculated using the cerebellum as a control region. The time interval to peak enhancement (TTP) maps were also calculated. Imaging findings–This exhibit will discuss the role of various perfusion parameters (CBF, CBV, MTT and TPP) in depicting the extent and severity of ischemic compromise in various areas of brain and their correlation with the angiography findings. Homodynamic changes after ICA-to-ECA bypass surgery are also described.
Format: Didactic-educational exhibit with pictorial depiction of image findings and MR perfusion maps in Moyamoya.
Teaching Points: 1. MR perfusion is a useful tool for relative quantitative evaluations of various perfusion parameters (CBF, CBV, MTT and TPP) in patients with Moyamoya syndrome. 2. MR perfusion, the presence and degree of perfusion abnormality can be detected which can be valuable for treatment decisions. 3. MR perfusion is also helpful in evaluating postoperative changes after ICA to ECA bypass
E382. High-Resolution Magnetic Resonance Imaging of the Substantia Nigra at 7.0 T
Sammet S.; Schmalbrock P.; Chakeres D. W.; Wassenaar P.; Koch R. M.; Knopp M. V. The Ohio State University, Department of Radiology, Columbus, OH
Address correspondence to S. Sammet (sammet.5{at}osu.edu)
Objective: The purpose of this in vivo ultra-high-field magnetic resonance imaging (MRI) study was to generate high-contrast, high-resolution images of the substantia nigra (SN). Histology using Calbindin staining has shown structural changes on a submillimeter scale between Parkinson's patients and healthy controls. Our objective was to assess brainstem contrast at 7.0 T and the feasibility for 3D-MRI to define the volume of the normal substantia nigra. Previous ultrahigh field MRI has demonstrated that the SN can be depicted with exquisite detail on 2D susceptibility-weighted and phase reconstructed images showing similar "flame-like" appears as histology.
Materials and Methods: Four healthy subjects were imaged at 7.0 T using a transmit/receive or an 8-channel SENSE head coil. 3D images were acquired with single or dual echo inversion recovery turbo field echo sequences using TR/TE/flip angle 13/2.2 and 11/8 and TI = 1550–2800 ms. Reconstructed voxel sizes ranged from 0.43 mm x 0.43 mm x 0.8 mm to 0.22 mm x 0.22 mm x 1.5 mm. For comparison, 2D susceptibility weighted images were acquired with a gradient echo sequence with TR/TE/flip angle of 600 ms/12 ms/55 (FOV = 24 x 18 cm, 1024 x 576 matrix, 2 mm slice thickness, skip 0.2 mm, reconstructed voxel 0.23 mm x 0.23 mm x 2.0 mm).
Results: On short TE images, the SN and red nucleus appeared bright compared to surrounding tissue. Excellent depiction of the SN as low signal structures was achieved with all long TE 3D sequences. Especially for high in-plane resolution, the spatial relation between vascular structures and the SN were depicted with exquisite detail. Whereas the SN was seen only on 2 slices with the 2D sequence, it could be seen in up to 6 slices in the 3D images. Both the transmit/receive and an 8-channel SENSE head coil had sufficient B1 homogeneity and inferior reach to allow for assessment of the brainstem.
Conclusion: Three-dimensional susceptibility weighted imaging of the SN is feasible at 7.0 T, and provides more detailed structural information than 2D. Further studies are needed to explain the unexpected bright appearance, possibly a T1 effect, of the SN on the short TE images. Three-dimensional ultra-high MRI may become a novel tool for noninvasive assessment of Parkinson's patients.
E383. Deep Space Infections of the Head and Neck: A Review of the Anatomy of the Deep Spaces of the Head and Neck and the Pathogens That Love Them
Wadhwa R.2; Gupta R. T.1; Sarver C.2; Nadimpalli S.1; Go J. L.2 1. Advocate Illinois Masonic Medical Center, Chicago, IL; 2. University of Southern California, Los Angeles, CA
Address correspondence to R. Wadhwa (rwadhwa{at}usc.edu)
Background: The deep spaces of the head and neck can be a confusing topic for residents and nonspecialty attendings. An accurate knowledge of the anatomy, including fascial planes and drainage patterns are essential in making correct diagnoses. We will attempt to elucidate the anatomy of the deep spaces of the head and neck as well as describe the common infections found in these spaces.
Key Issues: The key purposes of this exhibit are: 1. To provide a detailed description of the complex anatomy of the spaces of the head and neck. 2. To describe different types of infections which can occur within these compartments. 3. To provide imaging characteristics of these infections using both CT and MR imaging.
Format: The format will be didactic. The following are sample content headings: 1. Anatomy of the major fascial planes of the head and neck and the deep spaces of the neck 2. Major categories of pathogens which may secondarily disseminate within these spaces 3. Case examples utilizing CT and MR 4. Key imaging features (which may aid in distinguishing these various types of infection). 5. Summary and conclusions of the anatomy and infections.
Teaching Points: The major teaching points of this exhibit are: 1. To review the anatomy of the deep spaces of the head and neck, specifically looking at it from the standpoint of the resident/nonspecialty trained attending radiologist. 2. To demonstrate with both CT and MR imaging the various infections and their imaging characteristics within these spaces 3. To describe the potential and propensity for spread of these infections to the skull base and mediastinum. 4. To instill a sense of the importance of the radiologist's role in diagnosing and determining extent for possible surgical planning.
E384. Optimal Scanning Protocol of the MDCT Double-scan Technique Before Preoperative Virtual Planning of Dental Implant Placement. Experimental Study
Wojciechowski W.1; Kownacki P.2; Kownacki S.2; Urbanik A.1 1. Collegium Medicum, Jagiellonian University, Department of Radiology, Krakow, Poland; 2. Dental Clinic, Krakow, Poland
Address correspondence to W. Wojciechowski (wwadik{at}poczta.onet.pl)
Objective: The aim of the study was optimization of the examination parameters and evaluation of reliability of the MDCT double-scan images obtained with the Teeth-in-an-HourTM concept using a phantom of the human cadaver head.
Materials and Methods: With the use of a MDCT scanner SOMATOM Sensation (Siemens, Germany), CT-images of a phantom were performed: slice-collimation (10 x 0.75, 10 x 1.5 mm), slice-thickness (0.75, 1, 2, 3, 5 mm), pitch (0.5, 1, 1.5). Additionally, the analysis on various filters from H20f to H60f was performed. Qualitative analysis was done using the Teeth-in-an-HourTM concept (Nobel Biocare, Sweden), assessing possible artifacts in the image, and measurements of the bone structure on all filters in comparison with the real image.
Results: The quality of the phantom images was assessed as optimal for the slice thickness 0.75 and 1 mm. The use of various values of the pitch did not have statistically significant difference on the image quality. Application of various filters did not alter the parameters of the bone structure, however the use of lower filters (H30f and H40f) had a beneficial effect on the quality of 3D reconstruction. The arrangement of the "window" parameters in CT seemed to have a greater influence on the measurement and evaluation of the bone structure.
Conclusion: Slice-collimation and slice-thickness are the most important parameters in selection of the optimal scan-protocol. It is recommended to use, in the postprocessing, the above mentioned parameter succession with the application of various filters (H30f and H60f) at a stable arrangement of the "window" in the MDCT examination.
E385. 18 F FDG PET/CT Imaging in Head and Neck Oncology
Subramaniam R.; Lowe V.; Witte R. Mayo Clinic, Rochester, MN
Address correspondence to R. Subramaniam (subramaniam.rathan{at}mayo.edu)
Background: PET/CT imaging plays an important role in clinical decision making and management of head and neck oncological conditions such as larynx, tongue, parotid, thyroid and in lymph nodal metastasis from unknown primary. It is widely used to stage, restage, assess therapy response and guide treatment options in routine clinical care of oncological patients.
Key Issues: PET/CT imaging can demonstrate normal FDG uptake of head and neck structures, features of a diagnosis and stage patients in head and neck squamous cell carcinoma, lymphoma, melanoma and nodal metastasis. Therefore, it is important for interpreting physicians to understand the normal 18F FDG distribution and abnormal pattern of 18F FDG PET/CT appearances in a wide variety of head and neck conditions.
Format: Didactic neck spaces oncology
Teaching Points: 1. To learn normal 18F FDG uptake of head and neck. 2. To learn the spectrum of 18F FDG PET/CT findings in various head and neck oncological conditions.
E386. Arthritides of the Temporomandibular Joint: An Overview by MR Imaging
Takeyama P. H.2; Larheim T. A.1; Westesson P.2 1. Department of Maxillofacial Radiology, Institute of Clinical Dentistry, University of Oslo, Oslo, Norway; 2. Division of Diagnostic and Interventional Neuroradiology, University of Rochester Medical Center, Rochester, NY
Address correspondence to P. Takeyama (takeyama{at}hotmail.com)
Background: Arthritides are comprised of a heterogeneous group of disorders, both inflammatory and noninflammatory, that affect the joints of the body. The temporomandibular joint is no exception, although this joint tends to be overlooked by clinicians. Disease processes such as osteoarthritis, rheumatoid arthritis, juvenile idiopathic arthritis, psoriatic arthritis, and ankylosing spon-dylitis can affect the temporomandibular joint. Many factors including age, trauma, repetitive use, infection, genetic predisposition, and autoimmune response can play roles in development of arthritides. Patients may experience various symptoms such as pain and swelling in the joint area, stiffness and restricted range of mouth opening, dental occlusion problems, crepitation and clicking sounds, and disc displacement.
Key Issues: MRI is a useful imaging modality to evaluate various arthritides involving the temporomandibular joint. Imaging findings such as cortical erosions, marrow edema, disc displacement and destruction, bone and disc fragments, pannus, and synovial enhancement may be picked up with MRI. This educational exhibit will introduce the reader to MRI evaluation of the temporomandibular joint, compare normal joint appearance and anatomy with joints affected by various arthritides, and compare with other differential disease processes that may mimic the findings.
Format: Didactic and interactive digital presentation with selected imaging demonstrating key findings of various arthritides involving the temporomandibular joint. Normal anatomy and function will be illustrated along with MRI protocol utilized to evaluate the temporomandibular joint.
Teaching Points: 1. To become familiar with MRI anatomy and evaluation of the temporomandibular joint. 2. To understand disease processes of various arthritides and how they affect the temporomandibular joint. 3. To correlate the pathologic process of various arthritides of the temporomandibular joint with MRI imaging findings.
E387. Ultrasonography of Abnormal Neck Lymph Nodes
Shin L. K.; Chan J.; Jeffrey R. Stanford University Medical Center, Stanford, CA
Address correspondence to L. Shin (lshin{at}stanford.edu)
Background: Sonography is an attractive modality to evaluate neck lymph nodes. Identifying metastatic disease is a common indication with abnormal findings potentially changing a patient's prognosis and treatment regimen. However, abnormal appearing lymph nodes due to reactive and infectious etiologies can pose a diagnostic dilemma for the sonographer. As a result, understanding and identifying features of a normal and abnormal lymph node is critical, as well as familiarity with normal neck anatomy and proper sonographic technique.
Key Issues: This exhibit will be an overview of neck ultrasonography and several issues will be addressed: 1) Review of neck anatomy with respect to lymph node stations 2) Optimization of imaging techniques 3) Imaging findings of the normal gray scale lymph node morphology (size criteria, importance of nodal shape, node border characterization, significance of echogenicity) and normal Doppler vascular patterns and 4) Abnormal lymph node imaging findings including calcification morphology, cystic changes, abnormal vascularity, etc.
Format: Didactic and Quiz. Initial didactic component will be: Part 1: a) technical aspects of ultrasonography, b) neck lymph node anatomy c) normal gray scale lymph node morphology and d) normal Doppler lymph node vascular findings. Abnormal features of lymph node morphology and vascularity will be discussed in Part 2 with an emphasis on differentiating benign from malignant processes. The exhibit will conclude with Part 3 where the viewer will be quizzed on salient points of the didactic session. Questions will include unknown cases, general knowledge, neck sonography technique, and clinical management issues.
Teaching Points: 1) Understand basic neck anatomy as it pertains to lymph node classification and sonographic technique. 2) Identify sonographic features of normal neck lymph nodes. 3) Identify sonographic features of abnormal neck lymph nodes.
E388. Diffusion weighed MR in Graves' Disease: Value in Assessing Activity of the Disease and Prediction of Outcome
Abdel Razek A.; Rasem A. Mansoura Faculty of Medicine, Mansoura, Egypt
Address correspondence to A. Abdel Razek (arazek{at}mans.eun.eg)
Objective: To assess the activity and clinical course of Graves' disease with diffusion weighted MR imaging.
Materials and Methods: Forty eight consecutive patients with Graves' disease underwent diffusion MR imaging of the thyroid gland, thyroid scintigraphy with Tc-99m pertechnetate and thyroid function tests. Diffusion weighted MR images were acquired with a b-factor of 0.250 and 500 sec/mm2 using a single shot echo planar imaging. The scanning parameters were: TR = 10,000 ms, TE = 108 ms, bandwidth = 125 kHz, slice thickness = 4 mm. The time between diffusion MR, thyroid scintigraphy and function test was 2–7 days. Patients were divided on the basis of clinical and laboratory data into four groups: patients untreated at first diagnosis, patients undergoing drug treatment, patients in remission after withdrawal of therapy, and patients having a relapse of hyperthyroidism. The apparent diffusion coefficient (ADC) value of the thyroid gland correlated with thyroid function and Tc-99m uptake ratio. Twenty healthy subjects who served as a control underwent the same MR study.
Results: The mean ADC value of thyroid gland in active Graves' disease was 0.66 ± 0.12 x 10-3 mm2/sec in patients at initial diagnosis, 0.81 ± 0.17 x 10-3 mm2/sec in patients on an anithyroid drug and 0.72 ± 0.07 x 10-3 mm2/sec in patients with relapse of hyperthyroidism. The mean ADC in patients with remission was 0.94 ± 0.09 x 10-3 mm2/sec. There was a significant difference in mean ADC values of patients with active disease and patients with remission (p < 0.02). The mean ADC value correlated with serum free T3 (r value = 0.85) and Tc-99m uptake ratio of thyroid (r value = 0.91).
Conclusion: We concluded that diffusion weighted MR imaging of the thyroid gland can be used to assess the activity of Graves' disease. Also, it can be used for prediction of outcome of the disease after therapy.
E389. Comparison of Thyroid Nodule Detectability Using 7.5 MHz and 10 MHz Ultrasound Systems: Results from the Ukrainian-American Study of Thyroid Cancer and Other Thyroid Diseases Following the Chernobyl Accident
O'Kane P.3,; Brill A.5; McAuliffe M.2; Shelkovoy E.4; Nayda Y.4; Shpak V.5; Markov V.4; McConnell R.1; Ephstein O.4 1. Columbia University, New York, NY; 2. National Institutes of Health, Rockville, MD; 3. Thomas Jefferson University, Philadelphia, PA; 4. V.P. Komisarenko Institute of Endocrinology and Metabolism, Academy of Medical Sciences of the Ukraine, Kiev; 5. Vanderbilt University, Nashville, TN
Address correspondence to P. O'Kane (patrick.okane{at}jefferson.edu)
Objective: Little has been written comparing the abilities of ultrasound probes of different frequencies to detect thyroid nodules. During an ongoing longitudinal screening study of a high-risk, radiation-exposed population, the screening ultrasound equipment was changed from a 7.5-MHz system to a 10-MHz system. The objective of this study was to compare the abilities of the two ultrasound systems to detect thyroid nodules
Materials and Methods: A total of 84 patients with known thyroid nodules who had been referred for biopsy underwent examinations by a single sonographer using both systems. The sonographer was aware that the patient had been referred for FNA but did not have access to the data from the initial screening study. In 42 cases, the patient was scanned initially with a Toshiba SSA-240 A system with a 7.5-MHz mechanical sector probe and integrated standoff water pad; in 42 cases a 10-MHz Terason system running on a Dell laptop was used first. Nodule sizes and locations were recorded on comprehensive paper datasheets.
Results: In the 84 patients, 132 nodules were found with the 7.5-MHz system, 143 nodules with the 10 MHz system. No nodules were found on the 7.5-MHz system but not the 10 MHz. Of the 11 nodules found only on the 10-MHz system, 9 were <5 mm. One nodule >5 mm was found with the 10-MHz system but not identified with the 7.5-MHz system. In one case, a nodule was interpreted as an irregular nodule on the 7.5-MHz system and as two adjacent nodules on the 10-MHz system. In all cases, size measurements were within 1 mm on the two systems. There were no differences in localization. The 10-MHz system provided more detailed visualization of the internal characteristics of the nodules.
Conclusion: There was no significant difference in the ability of the 7.5-MHz and 10-MHz systems to detect nodules >5 mm in a high-risk population. The 10-MHz system was more sensitive for detection of nodules <5 mm and provided more detailed nodule characterization.
E390. Control of Local Neck Recurrence from Papillary Thyroid Carcinoma by Ultrasonography-guided Percutaneous Ethanol Injection
Kim M.2; Kim E.2; Kim B.1 1. Kangbuk Samsung Hospital, Seoul, South Korea; 2. Yonsei University of Medical College, Seoul, South Korea
Address correspondence to M. Kim (mines{at}yumc.yonsei.ac.kr)
Objective: To evaluate the efficacy of ultrasonography-guided percutaneous ethanol injection (PEI) for control of local neck recurrence from papillary thyroid carcinoma (PTC).
Materials and Methods: Thirty-seven biopsy-proven recurrent neck lesions were treated by PEI in 27
