Utility of magnetic resonance in the etiologic diagnosis of hypopituitarism

The diagnosis of hypothalamic-pituitary disorders relies on a combination of clinical and biochemical data and imaging techniques. During the last decade, computed tomography (CT) has been the best technique for the evaluation of the hypothalamuspituitary region, but in recent years magnetic resonance (MR) has improved the diagnostic efficiency of CT. We retrospectively review the clinical records of 40 hypopituitary patients from the endocrinology unit of our hospital. The aim of the present study was to establish the role of MR in the etiologic diagnosis and anatomic definition of hypopituitarism, when compared with CT. Secondarily, we studied the different pituitary hormones in this condition. The diagnoses were: 12 postsurgical hypopituitarism, 10 empty sella turcica, 7 Sheehan's syndrome, 5 idiopathic hypopituitarism, 3 pituitary disgenesis, 2 craniopharyngioma and 1 macroprolactinoma. GH was the most commonly affected hormone, followed by gonadotrophins, corticotrophin and thyrotrophin (100%, 94%, 76% and 68% respectively). In 24 patients both MR and CT studies were performed. MR was diagnostic in 22 patients, and CT in 15 patients (p < 0.05). MR offered improved diagnostic or anatomical data in 16 patients of the 24 in whom both techniques were performed (p < 0.05). We conclude that MR allows a better definition of the hypothalamus-pituitary region than CT, contributing to the etiologic diagnosis and improving the anatomical findings. Empty sella turcica should be considered a common cause of hypopituitarism.     

Automatic registration of pelvic computed tomography data and magnetic resonance scans including a full circle method for quantitative accuracy evaluation

The purpose of this study is to develop a method for registration of CT and MR scans of the pelvis with minimal user interaction and to obtain a means for objective quantification of the registration accuracy of clinical data without markers. CT scans were registered with proton density MR scans using chamfer matching on automatically segmented bone. A fixed threshold was used to segment CT, while morphological filters were used to segment MR. The method was tested with transverse and coronal MR scans of 18 patients and sagittal MR scans of 8 patients. The registration accuracy was estimated by comparing (triangulating) registrations of a single CT scan with MR in different orientations in a "full circle." For example, CT is first matched on transverse MR, next transverse MR is matched independently on coronal MR, and finally coronal MR is matched independently on CT. The product of the three transformations is the identity if all matching steps are perfect. Deviations from identity occur both due to random errors and due to some types of systematic errors. MR was registered on MR (to close the "circle") by minimization of rms voxel value differences. CT-MR registration takes about 1 min, including user interaction. The random error for CT-MR registration with transverse or coronal MR was 0.5 mm in translation and 0.4 degree in rotation (standard deviation) for each axis. A systematic registration error of about 1 mm was demonstrated along the MR frequency encoding direction, which is attributed to the chemical shift. In conclusion, the presented algorithm efficiently and accurately registers pelvic CT and MR scans on bone. The "full circle" method provides an estimate of the registration accuracy on clinical data.     

MRI: incidence and evaluation of size and form criteria in hypophysis-healthy probands and in patients with detectable microadenomas

Magnetic resonance imaging (MRI) was performed in 42 patients with proven microadenomas and in 42 patients with normal pituitary hormone analysis. The normal MRI--anatomy of the pituitary gland and its possible variations with measurement of the volume and comparison of the anatomy with that of the gland after changes caused by microadenomas has to our knowledge not yet described. In this study we measured the height, coronary and sagittal diameter of the pituitary gland in both groups as well as other indirect signs of microadenomas (asymmetry of the gland, sella turcica, and the stalk). The pituitary volume indicates the expansion of microadenomas much better than the gland height (and the other diameters). Normal pituitary glands showed a significant lower volume (525 +/- 137 mm3 [R = 225-800 mm3]) than patients with proven microadenomas (734 +/- 393 mm3 [R = 335-2800 mm3], p < 0.001). The normal pituitary gland and sella turcica show a large variety of anatomic variations. These variations are less frequent in healthy subjects (10-21%) than in patients with microadenomas (48-71%). The described criteria are of some value in diagnosis of a suspected gland hypertrophy or microadenoma. In 75% of the patients with normal pituitary parameters and in 12% of the patients with microadenomas no indirect adenoma criteria was found in our study.     

Specific changes in human brain following reperfusion after cardiac arrest

BACKGROUND AND PURPOSE: Very few reports are available on serial changes in human brain after cardiac arrest. The primary objective of this study is to investigate sequential neuroradiological changes in patients remaining in a persistent vegetative state following resuscitation after cardiac arrest. METHODS: We repeatedly studied eight vegetative patients resuscitated from unexpected out-of-hospital cardiac arrest using computed tomographic (CT) scanning and high-field magnetic resonance (MR) imaging at 1.5 T. RESULTS: In seven of the eight patients, CT scans obtained between days 2 and 6 features symmetrical low-density lesions in the bilateral caudate, lenticular, and/or thalamic nuclei. These ischemic lesions were persistently of low density on serial CT scans. In these seven patients, MR images demonstrated what were thought to be hemoglobin degradation products derived from minor hemorrhages localized in the bilateral basal ganglia, thalami, and/or substantia nigra. Diffuse brain edema in the acute stage and diffuse brain atrophy in the chronic stage were consistent neuroradiological findings. No abnormal enhanced lesions were demonstrated by CT scans. CONCLUSIONS: The most characteristic findings on high-field MR images were symmetrical lesions in the bilateral basal ganglia, thalami, and/or substantia nigra with specific changes suggestive of minor hemorrhages that were not evident on CT scans. We speculate that these minor hemorrhages result from diapedesis of red blood cells in these regions during the reperfusion period through the endothelium disrupted by ischemia-reperfusion insult.     

Ovarian cancer: comparison of findings with perfluorocarbon-enhanced MR imaging, In-111-CYT-103 immunoscintigraphy, and CT

PURPOSE: To determine the accuracy of breath-hold gadolinium- and perflubron-enhanced magnetic resonance (MR) imaging, immunoscintigraphy with indium-111-CYT-103 (planar and single photon emission computed tomography [CT]), and contrast material-enhanced CT for the detection of ovarian cancer prior to laparotomy. MATERIALS AND METHODS: Sixteen patients with primary (n = 3) or treated (n = 13) ovarian cancer underwent imaging of the abdomen and pelvis with each modality. All images were reviewed prospectively for tumor location, and results were compared with findings at surgery. RESULTS: With CT or MR imaging, tumor was detected in 11 of 13 (85%) patients compared with 11 of 12 patients (92%) with immunoscintigraphy. Per patient accuracy for CT was 81% compared with 75% for MR imaging and 86% for immunoscintigraphy. For detection of individual sites of tumor, the sensitivity of MR imaging was highest (81%) compared with CT (51%, P < .001) and immunoscintigraphy (50%, P < .01). The combination of MR imaging and immunoscintigraphy depicted 89% of sites of tumor involvement confirmed at laparotomy. CONCLUSION: MR imaging and immunoscintigraphy show promise for the evaluation of patients with ovarian cancer.     

Invasive pulmonary aspergillosis in AIDS: radiographic, CT, and pathologic findings

PURPOSE: To review the radiographic and computed tomographic (CT) manifestations of invasive pulmonary aspergillosis and to correlate the imaging and pathologic findings in patients with acquired immunodeficiency syndrome (AIDS). MATERIALS AND METHODS: Chest radiographs, CT scans, and pathologic specimens were reviewed retrospectively in 10 AIDS patients with proved invasive pulmonary aspergillosis. RESULTS: The most common radiographic finding was the presence of thick-walled cavitary lesions. Less common findings included nodules, consolidation, and pleural effusion. CT depicted more nodules and cavities than did radiography. The predominant pathologic abnormalities consisted of tissue invasion and abscess formation and angioinvasion with or without infarction. All patients had infection with Aspergillus fumigatus as well as other pathogens, the most common being cytomegalovirus and Pseudomonas aeruginosa. CONCLUSION: Thick-walled cavitary lesions are the most common radiologic manifestation of invasive pulmonary aspergillosis in AIDS. The findings are more numerous and better defined on CT scans. The radiologic findings reflect a spectrum of pathologic abnormalities.     

Studies on the antiviral mechanisms of protein kinase inhibitors K-252a and KT5926 against the replication of vesicular stomatitis virus

INTRODUCTION: We investigated the accuracy of MRI of the prostate with an endorectal surface coil in determing penetration of the prostatic capsule and invasion of seminal vescicles in prostate carcinoma. MATERIAL AND METHODS: Endorectal coil MRI (1 Tesla) was performed in 300 patients with biopsy-proved cancer. The PSA levels were always calculated and all the patients were examined with transrectal ultrasound. The imaging protocol included Turbo Spin Echo T2-weigthed (3900/150 TR/TE) axial and coronal images and T1-weigthed (650/15 TR/TE) axial images, 4 mm thick interleaved sections with .4 mm intersection gap, FOV 180 mm, 256 x 256 matrix (reconstruction 512). Seventy-five patients underwent radical prostatectomy and MR images were compared with pathologic findings of capsular penetration and invasion of seminal vescicles. The MR signs specific for capsular penetration were: deformation (irregularity) of capsular profile, capsular retraction with irregular margins, capsular interruption, obliteration of periprostatic adipose tissue, asymmetry of neurovascular bundles. RESULTS: MRI correctly depicted 37 of 45 pathologic stage T2 lesions and correctly depicted macroscopic capsular penetration (T3) in 18 of 23 cases. Microscopic capsular penetration was overestimated in all 7 cases. Sensitivity, specificity, accuracy, for microscopic and macroscopic capsular penetration were 60, 82, 73% respectively. Sensitivity, specificity, accuracy for macroscopic capsular penetration were 78, 82, 80% respectively. Sensitivity, specificity, accuracy for depiction of seminal vesicle involvment were 80, 100, 93%, respectively. The most reliable signs of capsular penetration were capsular interruption and invasion of periprostatic adipose tissue, while asymmetry of the neurovascular bundle was not seen. CONCLUSIONS: MRI provides accurate preoperative local staging. The two main limitations of MRI were the high rate of microscopic capsular penetration and the difficulty in detecting capsular penetration of tumor when the lesions are in the prostate apex. Prostate enlargement also made diagnosis more difficult.     

Evaluation of tibial plateau fractures: efficacy of MR imaging compared with CT

OBJECTIVE: CT is often used after plain films to evaluate fractures of the tibial plateau. Because MR imaging can show associated soft-tissue injuries as well as fractures, we hypothesize that MR is superior to CT for imaging these injuries. Accordingly, we compared the efficacy of MR imaging and CT in 22 patients with tibial plateau fractures. SUBJECTS AND METHODS: CT with two-dimensional reconstruction and MR examinations were performed in 22 patients with tibial plateau fractures. The images were interpreted by four radiologists and two orthopedic surgeons. Findings on CT scans and plain films were used to determine the configuration of the fractures and to classify them according to the Schatzker system. This was done with findings on MR images and plain films at a separate session. The MR images were also evaluated for ligamentous and meniscal injuries. A qualitative side-by-side comparison of two-dimensional CT scans and MR images for depiction of fracture configuration was done. Imaging results were correlated with observations from physical examinations in all patients and with surgical findings in 12 patients. RESULTS: All of the six types of fractures of the Schatzker classification were observed in this series. Comparison of two-dimensional CT reconstructions and MR images for depiction of fracture configuration revealed that the two techniques were equal in 14 patients, MR imaging was superior to CT in five patients, and CT was superior to MR imaging in three patients (who had very complex and comminuted fractures). In addition, MR imaging showed 12 complete ligamentous tears and 15 partial ligamentous tears in 15 (68%) of the 22 patients. MR showed meniscal injuries in 12 (55%) of the 22 patients. CONCLUSION: MR imaging was equivalent or superior to two-dimensional CT reconstruction for depiction of fracture configuration in most patients. In addition, MR showed significant soft-tissue injuries. We believe that MR imaging is the preferable imaging technique for most patients with fractures of the tibial plateau.     

Cerebral paragonimiasis in early active stage: CT and MR features

OBJECTIVE: Diagnosis of cerebral paragonimiasis in its early active stage is important because curative chemotherapy is possible. Accordingly, this study was undertaken to evaluate the CT and MR features of early active cerebral paragonimiasis. MATERIALS AND METHODS: We retrospectively reviewed the CT scans (n = 29) and MR images (n = 7) of the brain in 20 patients between 7 and 59 years old who had cerebral paragonimiasis in the early active stage. The diagnosis was based on a positive antibody test by enzyme-linked immunosorbent assay (ELISA) for paragonimiasis in serum and CSF. The diagnosis was confirmed surgically in seven patients. RESULTS: The most common and characteristic imaging finding was a conglomerate of ringlike enhancing lesions (grape-cluster appearance) with surrounding edema in one cerebral hemisphere in 11 patients (55%). Other nonspecific findings included a solitary ringlike lesion (n = 4) or irregular enhancing lesions (n = 2), localized hemorrhage with (n = 3) or without (n = 2) enhancing lesions, and a poorly defined non-hemorrhagic, nonenhancing lesion (n = 1). CONCLUSION: CT and MR findings of clustered ring-enhancing lesions, seen in approximately half of the cases of early cerebral paragonimiasis, are suggestive of cerebral paragonimiasis.     

Comparison of computerized tomography and magnetic resonance in the assessment of benign and malignant pleural diseases

To compare the diagnostic capabilities of Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) in differentiating benign from malignant pleural disease, we examined with MRI at 0.5 T forty-five patients with pleural lesions identified on CT scans. For 34 patients, a final diagnosis of malignant (n = 18) or benign (n = 16) disease was made. T1, proton density/T2 and enhanced T1-weighted spin-echo images were acquired. CT and MR images were independently studied by two observers, who were unaware of the final diagnosis. Various morphological features suggesting benign or malignant pleural disease were evaluated. On the basis of the morphological CT features, a final diagnosis of benignity of malignancy was expressed in terms of two different levels of confidence-probable or definitive. The MR signal intensity of pleural lesions was compared with that of intercostal muscles (isohypointense or hyperintense). No significant differences were observed between CT and MR morphological findings. High signal intensity on proton density/T2-weighted images was observed in all malignant lesions and in 2 benign lesions (100% sensitivity, 87% specificity). In the absence of this sign (i.e., isointense or hypointense signal), the lesions were always benign (100% negative predictive value). All the definitive CT diagnoses were correct, while 6 of 17 probable CT diagnoses were incorrect. In the subgroup of lesions misinterpreted with CT, MR signal intensity on long-TR images always allowed the correct differentiation of benign from malignant conditions. To conclude, MR signal intensity is a valuable additional feature to differentiate benign from malignant pleural disease. We suggest the use of MRI in the pleural lesions where the level of confidence of CT diagnosis is low.     

Exercise and cellular innate immune function

PURPOSE: To determine, in three-dimensions, the difference between prostate delineation in magnetic resonance (MR) and computer tomography (CT) images for radiotherapy treatment planning. PATIENTS AND METHODS: Three radiation oncologists, considered experts in the field, outlined the prostate without seminal vesicles both on CT, and axial, coronal, and sagittal MR images for 18 patients. To compare the resulting delineated prostates, the CT and MR scans were matched in three-dimensions using chamfer matching on bony structures. The volumes were measured and the interscan and interobserver variation was determined. The spatial difference between delineation in CT and MR (interscan variation) as well as the interobserver variation were quantified and mapped three-dimensionally (3D) using polar coordinates. A urethrogram was performed and the location of the tip of the dye column was compared with the apex delineated in CT and MR images. RESULTS: Interscan variation: CT volumes were larger than the axial MR volumes in 52 of 54 delineations. The average ratio between the CT and MR volumes was 1.4 (standard error of mean, SE: 0.04) which was significantly different from 1 (p < 0.005). Only small differences were observed between the volumes outlined in the various MR scans, although the coronal MR volumes were smallest. The CT derived prostate was 8 mm (standard deviation, SD: 6 mm) larger at the base of the seminal vesicles and 6 mm (SD 4 mm) larger at the apex of the prostate than the axial MRI. Similar figures were obtained for the CT and the other MRI scans. Interobserver variation: The average ratio between the volume derived by one observer for a particular scan and patient and the average volume was 0.95, 0.97, and 1.08 (SE 0.01) for the three observers, respectively. The 3D pattern of the overall observer variation (1 SD) for CT and axial MRI was similar and equal to 3.5 to 2.8 mm at the base of the seminal vesicles and 3 mm at the apex. CONCLUSION: CT-derived prostate volumes are larger than MR derived volumes, especially toward the seminal vesicles and the apex of the prostate. This interscan variation was found to be larger than the interobserver variation. Using MRI for delineation of the prostate reduces the amount of irradiated rectal wall, and could reduce rectal and urological complications.     

Thermoregulatory responses of mesic and xeric rodent species to photoperiod manipulations

PURPOSE: To evaluate hypertrophied bronchial arteries on thin-section computed tomographic (CT) scans in patients with bronchiectasis by using CT angiographic correlation. MATERIALS AND METHODS: Spiral CT angiography was performed prospectively in 14 patients (eight men, six women; age range, 34-71 years) with bronchiectasis who were suspected of having bronchial arterial hypertrophy at thin-section CT (performed without contrast medium). The inclusion criteria were tubular (in six patients) or nodular (in 14 patients) areas of soft-tissue attenuation that had an appearance unlike that of lymph nodes at thin-section CT and that were within the mediastinum and around the central airway. These findings were subsequently correlated with the spiral CT angiographic findings. RESULTS: At comparative analysis of thin-section CT scans and CT angiograms, seven of the eight (88%) tubular lesions and 19 of the 36 (53%) nodular lesions in the mediastinal soft tissue were proved to be hypertrophied bronchial arteries. All of the six (100%) tubular and 19 of the 21 (90%) nodular lesions around the walls of the main (primary) and lobar bronchi were hypertrophied bronchial arteries. In eight (57%) patients, CT angiograms showed 11 intraluminal protrusions caused by hypertrophied bronchial arteries in the main bronchi, lobar bronchi, or both. CONCLUSION: Nodular and tubular structures in the mediastinum and around the central airway on thin-section CT scans in the patients with bronchiectasis are suggestive of hypertrophied bronchial arteries. Recognition of the hypertrophied bronchial artery can be critical for the bronchoscopist.     

Using unenhanced helical CT with enteric contrast material for suspected appendicitis in patients treated at a community hospital

OBJECTIVE: We evaluated the accuracy of unenhanced helical CT with enteric contrast material in the diagnosis of appendicitis in children and adults treated at a community hospital. SUBJECTS AND METHODS: Over an 8-month period, 100 consecutive patients with right lower quadrant pain and suspected appendicitis were prospectively evaluated. Thin-collimation helical CT scanning was performed after administration of enteric contrast material. CT interpretations were correlated with surgical pathology (45 patients) and clinical follow-up (55 patients). RESULTS: The findings of 33 CT scans were interpreted as positive for appendicitis (29 true-positives and four false-positives), and the findings of 67 were interpreted as negative for appendicitis (66 true-negatives and one false-negative). Sensitivity was 97%, specificity was 94%, accuracy was 95%, positive predictive value was 88%, and negative predictive value was 99%. In the 67 CT scans with negative findings for appendicitis, an alternative diagnosis was made for 36 patients (54%). CONCLUSION: Unenhanced helical CT with enteric contrast material for the evaluation of appendicitis can be implemented in a community hospital. In our study, such imaging achieved excellent accuracy.     

Effect of Saccharomyces boulardii against experimental oral infection with Salmonella typhimurium and Shigella flexneri in conventional and gnotobiotic mice

OBJECTIVE: To compare serum CA 125 assays with computed tomography (CT) and transvaginal ultrasound (TVUS) for early detection of disease recurrence in patients with ovarian cancer. METHODS: Sixty-two patients with non-mucinous epithelial ovarian cancer who had positive CA 125 levels (> 35 U/ml) were studied. We performed a retrospective review to determine the usefulness of serum CA 125 measurements. Setting the cut-off limit at either 35 U/ml or 16 U/ml, the accuracy of CA 125 measurements was compared with that of CT scanning, TVUS and operative findings at second-look laparotomy (SLL) in the early detection of recurrent tumors. RESULTS: Compared with SLL, both the specificity and the positive predictive value of CA 125 measurements were 100% at 16 and 35 U/ml. The sensitivity and the negative predictive value were 30.8 and 71.9%, respectively, below 35 U/ml and 53.8 and 79.3%, respectively, below 16 U/ml. The false-negative rate of CT was 36.1%. When the cut-off limit was reduced from 35 to 16 U/ml, 57.1% of patients considered to be in remission were reclassified as having persistent disease. A complete response confirmed by CT did not represent remission: CA 125 levels were 7.5-fold higher at the time of re-evaluation by CT. TVUS also lagged behind CA 125 assays in detecting disease recurrence. The sensitivity of ultrasound appeared to be lower than that of CT because it failed to detect extrapelvic lesions. CONCLUSION: A screening threshold (cut-off level) of 16 U/ml for CA 125 should be used to detect recurrent serous ovarian adenocarcinoma. Although ultrasound is a convenient method of detecting intrapelvic lesions, and has cost benefit, CT is necessary to detect extrapelvic recurrence. Neither CT nor ultrasound are more accurate than serial CA 125 assays in detecting disease recurrence.     

Comparison of two-dimensional MR digital subtraction angiography of the lower extremity with x-ray angiography

PURPOSE: To perform a preliminary evaluation of the diagnostic accuracy of contrast-enhanced, two-dimensional (2D) magnetic resonance (MR) digital subtraction angiography (DSA) of the lower extremity by comparison with x-ray angiography (XRA). MATERIALS AND METHODS: Forty lower extremities in 22 patients were imaged at multiple levels with both XRA and 2D MR DSA. Images were retrospectively analyzed by three radiologists in a randomized blinded manner. Seventeen vascular segments were graded as an insignificant lesion, a significant lesion, or as an occlusion. With the use of segments well depicted with XRA as the gold standard, the sensitivity, specificity, and accuracy of 2D MR DSA, as compared with XRA, were evaluated. The McNemar-Stuart-Maxwell test was performed to determine the significance of any differences found. RESULTS: Three hundred eighty-three arterial segments were evaluated with both techniques. Three hundred one segments were well depicted with XRA. There was no significant difference between 2D MR DSA and XRA for assessing the degree of occlusive disease in these 301 segments (.25 < P < .5). The sensitivity, specificity, and diagnostic accuracy of 2D MR DSA were found to be 90%, 98%, and 93%, respectively. CONCLUSION: Two-dimensional MR DSA is an accurate method for assessing arterial lesions in the lower extremity.     

Molecular analysis of the malR gene of Clostridium butyricum NCIMB 7423, a member of the LacI-GalR family of repressor proteins

OBJECTIVE: The purpose of our study was to evaluate helical CT using axial, coronal, and three-dimensional (3D) reconstruction in the examination of potential kidney donors and to compare the results with angiography and surgery when possible. We also reviewed previously published reports. SUBJECTS AND METHODS: Thirty-six patients underwent unenhanced and enhanced helical CT (3-mm collimation, 150-170 ml of i.v. contrast material injected at 4 ml/sec; pitch 1.5; 17-sec scan delay) with coronal and 3D shaded-surface-display reconstructions made from 1.5-mm overlapping reconstructions. All CT scans were interpreted independently of each other by two observers unaware of other findings. A third observer, who was aware of other findings, also interpreted the images. Results were compared with angiography (24 cases) and surgery (24 cases). Our results are compared with those of other investigators. RESULTS: Axial CT was the best method for detecting accessory arteries (24%) and early branching (10%); it also detected relevant venous and ureteral anatomy and incidental findings. The coronal and 3D images rarely added information that resulted in changed patient treatment. CT findings were concordant with those of digital angiography in 89% of kidneys and were 98% concordant with surgery. CONCLUSION: Helical CT can show arterial, venous, and ureteral anatomy and can also show important incidental findings. If only helical CT is used, a few small accessory vessels and an occasional renal artery stenosis may be missed. Axial images are generally diagnostic and may be supplemented by multiplanar and 3D images read concurrently.     

Wegener granulomatosis: CT and MR findings

PURPOSE: To demonstrate the spectrum of CT and MR imaging findings in patients with Wegener granulomatosis and to determine how often these findings could be attributed to either direct extension from paranasal or orbital disease sites, remote granulomas, or central nervous system (CNS) vasculitis. METHODS: We retrospectively reviewed the CT or MR studies of 15 patients with Wegener granulomatosis. RESULTS: Abnormal findings were seen in 7 patients (5 examined with MR imaging, 2 with CT). Findings included dural thickening and contrast enhancement (3 patients), infarcts (2 patients), regions of hyperintense signal on T2-weighted MR images (2 patients), and abnormal MR signal in the brain stem (2 patients). Three patients with imaging findings of dural enhancement and thickening were thought to have remote granulomatous lesions involving the dura. No patients had extension from sites external to the CNS or clinical findings suggestive of CNS vasculitis. CONCLUSION: The spectrum of CT and MR findings in Wegener granulomatosis includes dural thickening and enhancements cerebral infarction, and MR signal abnormalities in the brain stem and white matter. Presumed remote granulomatous lesions were the most common causes of CNS findings in this study. Complications related to non-CNS disease (eg, hypertension, endocarditis) also appear to have played a role in some patients.     

Supratentorial arachnoid cyst and associated subdural hematoma: neuroradiologic studies

CT and MR images of 8 patients with supratentorial arachnoid cyst complicated by subdural hematoma were studied and compared with those of 8 patients who developed nontraumatic subdural hematoma without arachnoid cyst. Of the 8 patients with supratentorial arachnoid cyst, CT and MR disclosed temporal bulging and/or thinning of the temporal squama in all 6 patients with middle fossa arachnoid cysts, and the thinning of the calvaria was evident in another patient with a convexity cyst. Calvarial thinning at the site corresponding to interhemispheric arachnoid cyst was clearly depicted on coronal MR images. In contrast, none of the 8 young patients with nontraumatic subdural hematoma without arachnoid cyst had abnormal calvaria. Temporal bulging and thinning of the overlying calvaria were identified as diagnostic CT and MR features of arachnoid cyst with complicating intracystic and subdural hemorrhage. Radiologists should be aware of this association and should evaluate the bony structure carefully.     

Fast fluid-attenuated inversion recovery (FLAIR) compared with T2-weighted spin-echo in the magnetic resonance diagnosis of mesial temporal sclerosis

RATIONALE AND OBJECTIVES: The authors compare coronal fast fluid-attenuated inversion recovery (FLAIR) with coronal T2-weighted spin-echo (SE) magnetic resonance (MR) techniques in the diagnosis of mesial temporal sclerosis (MTS). METHODS: In this prospective study, the authors assessed MR scans of 30 patients with drug-resistant temporal lobe epilepsy (based on clinical symptomatology and electroencephalographic registrations) with MR features suggestive of MTS. MR scans of age-, sex-, and scanner-matched patients, referred for MR assessment of white matter disease, without a history of epilepsy and with no visible abnormalities on MR, were used as controls. In 16 patients the MR diagnosis was confirmed by histologic abnormalities consistent with MTS. Coronal T2 SE and FLAIR images of patients and controls were presented to two experienced radiologists in random order for independent blinded review. Hippocampal and associated extrahippocampal temporal lobe abnormalities were used for the diagnosis of MTS. RESULTS: The sensitivity of observer A was 97% for the T2 SE sequence and 100% for the FLAIR; the specificity of observer A for both techniques was 100%. The sensitivity of observer B was 53% for T2 SE and 83% for FLAIR; the specificity for observer B was 93% for the T2 SE and 100% for FLAIR. CONCLUSION: Coronal FLAIR images provide a similar or increased yield in the detection of MTS compared with T2-weighted SE images.     

Ultrasonic classification of carotid plaques causing less than 60% stenosis according to ultrasound morphology and events

Carotid plaque morphology studied by ultrasound has been used to classify 3 types of bifurcation plaques, producing less than 60% stenosis on duplex scanning: Type A, the homogeneous, highly echogenic plaque; Type B, the heterogeneous (mainly echogenic, B-1 or mainly echolucent, B-2) plaque; Type C, the complex plaque with irregular surface, echogenic and/or echolucent with calcifications. One hundred asymptomatic subjects in each plaque group were included in a prospective 4-year follow-up study to evaluate clinical events and brain damage by yearly cerebral CT and MR scans. After four years 96 subjects with type A plaque, 89 with type B-1 and 67 with type C plaques completed the study. While there were no clinical events or positive cerebral scans in subjects with type A plaques there was a significantly increasing number of cerebral and vascular events in subjects with plaque B and C type with a zero mortality in the plaque A group, a 2.24% mortality in type B plaques and a significantly higher (p > 0.05) mortality (13.4%) in type C plaques. CT and MR scans revealed brain damage which had been totally asymptomatic with MR detecting a larger number of lesions. Also the number of cerebral lesions observed by CT/MR were significantly greater than the number of recorded clinical episodes. ECG stress test revealed a larger number of asymptomatic coronary disease in the C type plaques. In conclusion ultrasound plaque morphology is linked to different incidences of cerebral and cardiac events, brain damage and asymptomatic coronary disease. Also CT and MR may reveal lesions which do not cause signs or symptoms.