MRI Findings of Intracranial Hemangioblastoma

PURPOSE: Complete resection of the tumor nodule(mural nodule or solid portion of the tumor) is the essential goal of surgical treatment for heman-gioblastoma. The purpose of this study was to classify the morphologic types of intracranial hemangioblastoma on MRI and to compare the location and contour of tumor nodule on MRI with those on angiography. MATERIALS AND METHODS: The MRI findings of 34 lesions(38 lesions if 4 spinal cord lesions were included) in 26 patients(17 males and 9 females, range of age, 18-67 years, mean, 39 years) with surgically and histopathologically proved intracranial hemangioblastomas were reviewed. Seventeen patients underwent CT scanning in a short interval. Contrast-enahnced T1 -weighted imaging pa- tterns of hemangioblastoma were classified according to Ho's morphologic types. The location and contour of tumor nodule were compared between MRI and angiography in 15 patients(24 lesions). RESULTS: By location, cerebellar hemisphere was predominated(55%), followed by cerebellar vermis(26%), supratentorial region(5%), and medulla oblongata (3%). Spinal cord lesions(11%) were seen in 3 patients of 5 von HippeI-Lindau diseases. The frequency of morphologic types was as follows; Type 1 (purely cystic), 3%, Type 2(mural nodule), 50%, Type 3(cyst with wall enhancement), 3%, Type 4 (cystic nodule), 15%, Type 5(solid with internal cyst), 9%, and Type 6(solid), 20%. All tumor nodules(33 lesions) enhanced intensely with intravenous contrast material on MRI, of which 24 lesions(in 15 patients) revealed hypervascular masses fed by pial arteries on angiography. They were superficial and abutted pia mater partially or in large portion on both MR I and angiography. CONCLUSION: Over 70% of intracranial hemangioblastomas had a surrounding cyst, and superficial, pial-based location and number of the tumor nodules on MRI was correlated well with those on angiography. MRI is the examination of choice for preoperative evaluation of intracranial hemangioblastoma.

Comparison of Clinical Application Modes of 3D TOF MR Angiography in the Brain: Normal Volunteers Study

PURPOSE: To compare the various imaging techniques including application of magnetization transfer(MT), administration of IV contrast materials, and imaging time after injection of contrast materials in 3D time-of-flight(TOF) cerebral magnetic resonance angiography(MRA) in normal volunteers. MATERIALS AND METHODS: Each of 11 healthy volunteers was prospectively studied with 3D TOF cerebral MRA using various imaging parameters. Various parameters of 3D TOF MRA were 1) pre-enhanced magnetization transfer(MT), 2) postenhanced MT, immediate phase, 3) postenhanced MT, 10-minutes delayed phase, 4) postenhanced MT, 20-minutes delayed phase, 5) pre-enhanced non-MT, 6) postenhanced non-MT, immediate phase, 7) postenhanced non-MT, 10-minutes delayed phase, 8) postenhanced non-MT, 20-minutes delayed phase. Image qualities of various parameters were compared with regard to depiction of cerebral arteries and veins by visual assessment For statistical analysis paired t-test was used. RESULTS: In pre-enhanced MRA, images with MT mode were better in arterial visualization than those with :n0n-MT mode(p<0.01). Postenhanced MT and non-MT images were better in arterial and venous visualization !than pre-enhanced MT and non-MT images(p<0.01), respectively. Images obtained immediately after injection of contrast material were better in both arterial and venous visualization than delayed images(p<0.01). CONCLUSION: Postenhanced cerebral 3D TOF MRA with MT obtained immediately after injection of contrast materal is the best to increase visualization of both cerebral arteries and veins, and may be indicated in some cranial vascular diseases.

The Role of IVIRI in Early Ankylosing Spondylitis: Emphasis on the Sacroiliac and Hip Joints

PURPOSE: In clinically suspected ankylosing spondylitis of sacroiliac (SIJ) and hip joints with normal or minimal secondary bone change in simple X-ray films, we evaluated the role of MRI in sacroiliac and hip joints. MATERIALS AND METHODS: Authors evaluated 11 cases (36 joints;SIJ 14, hip 22) confirmed as spondylitis by clinical, laboratory, and radiologic findings, and compared the detectability of involvement of joints by simple X-ray film and MRI. Authors analysed MR findings for the presence of pannus and its si, intensities (SI), change of articular cartilage, bony erosion and sclerosis, subchondral bone cysts,.~ osteophytosis, bone marrow edema, joint effusion, adjacent soft tissue change, and contrast enhancement ofi pannus. RESULTS: MRI detected not only 20 joints (SIJ 11, hip 9) detected in simple X-ray, but also additional 7 joints (SIJ 3, hip 4). MRI depicted simultaneous involvement of SIJ and hip joints in 5 of 11 cases (SIJ 10 joints, hip9 joints), and bilateral involvement of SIJ and hip joints in 4 among the 5 cases. MRI also demonstrated pannus, which were not detected in conventional films, as intermediate SI on T1WI and high SI on T2WI, in all 27 joints (SIJ 14, Hip 13). Gd-DTPA enhanced T1WI revealed enhancement of pannus in 7 cases (17 joints). CONCLUSION: MRI was a valuable modality in evaluation of clinically suspected ankylosing spondylitis of SIJ or hip joints with normal or minimal secondary bone change in simple X-ray. Simultaneous evaluation of SIJ and hip joints is suggested in clinically suspected ankylosing spondylitis or other joint diseases.

Gray Matter Heterotopias: MR and Clinical Features

PURPOSE: To evaluate types of gray matter heterotopias, associated brain anomalies, and its correlation with the patterns of seizure. MATERIALS AND METHODS: We evaluated retrospectively 19 patients(male :female=10:9, mean age 21 years) with gray matter heterotopias on brain MRI. Using 1.0T superconducting MR unit, spin echo TI-, proton-density- and T2-weighted images in axial, coronal and sagittal planes were obtained. RESULTS: Types of gray matter heterotopias were single subependymal in four patients, multiple subependymal in one, focal subcortical in eight, diffuse subcortical in two, mixed multiple subependymal and focal subcortical in four. Associated anomalies were seen in 11 patients:other neuronal migration anomalies in eight patients, corpus callosum agenesis in two, and combined holoprosencephaly and Dandy-Walker malformation in one. Fifteen patients had seizure. The patterns of seizure were not correlated with the types of heterotopias. CONCLUSION: In addition to subependymal, focal subcortical, and diffuse subcortical types, gray matter heterotopias included mixed variant of of multiple subependymal and subcortical type. Schizencephaly was the most common form of accompanying anomalies, and patterns of seizure were not correlated with types of gray matter heterotopias, even though main clinical menifestation was seizure.

Analysis of High Signal Intensities of Nontumorous Conditions of Corpus Callosum on Magnetic Resonance T2-Weighted Images

PURPOSE: To evaluate high signal intensity of nontumorous conditions of corpus callosum on T2-weighted MR images. MATERIALS AND METHODS: Fourty nine patients with nontumorous high signal intensities involving corpus callosum on sagittal T2-weighted image were restrospectively analyzed. Nontumorous condition of corpus callosum were diffuse axonal injury(DAI, 19 cases), cerebral infarctions(16 cases), multiple sclerosis(MS, 5 cases), Wilson's disease(2 cases) and hydrocephalus(7 cases) that were diagnosed by clinical and MR findings. Numbers, configuration, involved thickness and sites of high signal intensities of corpus callosum were analyzed. RESULTS: DAI and infarctions showed either single or multiple lesions. MS and hydrocephalus showed multiple lesions, but Wilson's diseases showed single lesion. In DAI, infarctions and MS the lesions involved any part of corpus callosum, splenium in WIIson's disease, and all parts of corpus callosum in hydrocephalus. Wilson's disease showed only partial thickness involvement, and others involved partial or full thickness of corpus callosum. Configuration of high signal intensity was linear in most cases of hydrocephalus, and oval in Wilson's disease, and oval and confluent in MS, and variable in DAI and infarctions. CONCLUSION: High signal intensities of nontumorous conditions of corpus callosum revealed variable findings, and therefore, analysis of nontumorous high signal intensities of corpus callosum is not made by only MR findings but by conjuction with clinical aspects.

Is It Useful for Distinguishing between Benign and Malignant Solid Breast Masses? : Diagnostic Criteria of Japan Society of Ultrasonics in IVledicine(JSUM)

PURPOSE: To evaluate the effectiveness and the most accurate element of the diagnostic criteria of the Japan Society of Uitrasonics in medicine(JSUM, Nov. 1989) for distinguishing between benign and malignant solid breast masses on the US. METHODS AND MATERIALS: We analyzed the ultrasonic findings of histopathologically proved 51 fibroadenomas, 12 fibrocystic disease, and 39 breast cancers in relation to the diagnostic criteria of the JSUM (shape, border, boundary echo, internal echo, posterior echo, lateral echo, and depth/width ratio). RESULTS: The number of cases of fibroadenoma, fibrocystic disease, and breast cancer corresponding to the diagnostic criteria was in the shape(26/51, 5/12, 33/39), border(41/51, 9/12, 29/39), boundary echo(48/51, 12/12, 27/39), internal echo(43/51, 9/12, 24/39), posterior echo(32/51, 3/12, 21/39), and lateral shadowing(15/51, 1/12, 35/39). All diagnostic criterias showed statistical significance for differentiation of benign/malignant breast mass on the US(Chi-square test: p<0.05). The order of accuracy was boundary echo, internal echo, and border. The mean of depth/width ratio was 0.54 +/- 0.15, 0.52 +/- 0.12, and 0.69 +/- 0.21 in fibroadenoma, fibrocystic disease, and breast cancer respectively and it had statistical significance for differentiation of benign/malignant breast mass on the US(ANOVA test: p=0.0002). CONCLUSION: The diagnostic criteria of JSUM is effective for differentiation of benign/malignant breast solid masses on the US and has accuracy in the order of boundary echo, internal echo, and border. Depth/width ratio also has statistical significance.

High Signal Intensity of the Septum Pellucidum at MR Imaging:Significance in Hydrocephalus

PURPOSE: To evaluate the significance of high signal intensity of the septum pellucidum in hydrocephalus on proton density-weighted brain MR images. MATERIALS AND METHODS: Authors reviewed the MR images of 418 cases of patients with normal(175 cases), hydrocephalic(35 cases), atrophic(58 cases), and other groups(150 cases) retrospectively. We analyzed the signal intensity of the septum pellucidum in the normal group and the incidences of high signal intensities of periventricular area of frontal horn of lateral ventricle(area 1), periventricular area except area 1(area 2), callososeptal area(area 3), and septum pellucidum(area 4) in the normal and abnormal groups. RESULTS: In the normal group, the septurn pellucidum was isointense to the head of caudate nucleus on proton density-weighted image. High signal intensity of the septurn pellucidurn was seen in 31 cases (22 cases of hydrocephalus, 5 cases of brain atrophy, and 4 cases of others), and showed high specificity(91.4%) for hydrocephalus in spite of low sensitivity(62.9%), as compared with periventricular hyperintensities of other areas. CONCLUSION: High signal intensity of the septum pellucidum on proton density-weighted image may be caused by transependymal CSF migration in the patients with hydrocephalus, and considered as an additional finding of hydrocephalus in the cases of ventriculomegaly.

Ring Lesions in MR Imaging of the Liver

PURPOSE: The purpose of this study is to find some points that may help the differential diagnosis of ring lesions in magnetic resonance (MR) imaging of the liver through recognition of the characteristics of the morphology and the signal intensities of the ring lesions. MATERIALS AND METHODS: T1- and T2-weighted axial spin-echo images and gadolinium-enhanced Tl-weighted images were obtained with a 1.0 T superconducting MR imager. We reviewed the MR findings of 23 hepatic ring lesions which were confirmed as hepatocellular carcinomas (13), metastases (4), liver abscesses (4), hydatid cyst (1), and hematoma (1). RESULTS: There were 19 single rings and 4 double rings (all the cases were liver abscesses) on Tl-weighted images, and 8 single rings and 14 double rings on T2-weighted images. The signal intensity of the ring was low in hepatocellular carcinoma on Tl-weighted images and in hydatid cyst on T2-weighted images. It was high on Tl-weighted images in subacute hemaroma. Target lesion as an inner high-signal-intensity ring surrounded by a high-signal-intensity ring on T2-weighted images was seen in metatasis, liver abscess, and hepatocellular carcinoma. CONCLUSION: It is helpful to recognize the chracteristics of morphology and signal intensities of the ring lesions in the differential diagnosis of hepatic focal lesions.

Splenic Artery Pseudoaneurysm Complicating Chronic Pancreatitis: A Case Report

Splenic artery pseudoaneurysm is a relatively rare and potentially life-threatening complication of chronic pancreatitis. The authors present a case of splenic artery pseudoaneurysm complicating ,chronic pancreatitis. It was converting into a pseudoaneurysm by vessel rupturs. In this case report, color doppler US, CT, and MRI made the definite diagnosis.

Comparative Evaluation of MR Imaging Findings of Spinal Neurilemmomas and Neurofibromas

PURPOSE:To find out the differential points between spinal neurilemmomas and neurofibromas. MATERIALS AND METHODS: Fourteen patients with pathologically proven neurilemmomas(n--6) and neurofibromas(n=8) of spinal canal were studied using magnetic resonance(MR) imaging. Contrast enhancement was performed with Gd-DTPA in all 14 patients. The size and shape of the tumor, absence or presence of adjacent bone erosion, location and extent of the tumor, signal intensity, degree and pattern of Gd-DTPA enhancement of the tumor were retrospectively analyzed. RESULTS: Rim enhancement was seen in five of six patients(83%) with neurilemmomas and three of eight patients(38%) with neurofibromas. Neurilemmomas showed moderate to marked enhancement in five of six patients(83%), whereas neurofibromas showed moderate to mild enhancement in all 8 cases(100%). The average size in longest diameter of the tumors was 2.8cm in neurilemmomas, while 5.4cm in neurofibromas. Neurilemmomas showed ovoid shape in 5 of 6 patients, no extra- or intradural extension, and erosion of adjacent bone in one patient, whereas neurofibromas showed Iobular shape in 6 of 8 patients, extra- or intradural extension in 6 of 8 patients, and erosion of adjacent bone in 4 of 8 patients. CONCLUSION: In differentiating neurofibroma from neurilemmoma, size, shape, extent of the tumor, absence or presence of adjacent bone erosion, and pattern and degree of enhancement of the tumor may be helpful.