PURPOSE: The purposes of this study were to analyze the MR findings of medulloblastoma, and to evaluate the subarachnoid dissemination and the significance of contrast enhanced MR of brain and spine for tumor.. MATERIALS AND METHODS: The preoperative brain MR studies of 18 patients (9 males, 9 females;mean age, 9.4 years) with surgically proved medulloblastomas were retrospectively reviewed to characterize these neoplasms with regard to their location, size, MR signal intensity, appearance after contrast enhancement, presence of cyst and necrosis, subarachnoid dissemination, and other associated findings. In 14 patients postoperative spine MR studies were evaluated for staging and therapeutic planning. RESULTS: The most frequent location of medulloblastoma was the inferior vermis and the mean tumor size was 4.1 x 3.6 x 3.9 cm. On Tl-weighted image, medulloblastomas generally had low to intermediate signal, predominantly hypointense relative to white matter. On T2-weighted image, medulloblastomas showed modetately high signal, hyperintense relative to white matter. Inhomogeneous contrast enhancement was demonstrated in 13 patients(72.2%) after injection of gadopentetate dimeglumine(Gadolinium). Cyst and necrosis within the tumor were visualized in 15 patients(83.3%). Subarachnoid disseminations of medulloblastomas were noted in 11 patients(61.1%), of which 6 demonstrated intracranial and 2 intraspinal dissemination. Three had both intracranial and intraspinal dissemination. In nine cases with intracranial lesions, there were intraparenchymal mass formation(7), subarachnoid nodules(5), infundibular lesions(2) and diffuse gyral enhancement(I). In five cases with intraspinal lesions, there were extramedullary intradural small nodules(3), central canal nodules(2), intradural masses(I)and fine nodular and sheet-like leptomeningeal enhancement(1). Other associated findings included intratumoral hemorrhage(11.1%), per/tumoral edema(44.4%), tonsillar herniation(44.4%), hydrocephalus(88.9%) and calcification(44.4%). CONCLUSION: Medulloblastomas revealed low to intermediate signal intensity on Tl-weighted image and intermediate to moderately high signal intensity on T2-weighted image, relative to cerebellar white matter. Medulloblastomas were solid tumors with cystic necrosis, which showed inhomogeneous enhancement and subarachnoid disseminations to the intracranial and intraspinal spaces after Gd-DTPA enhancement. Gd-enhanced MR of brain and spine was an useful diagnostic modality in preoperative diagnosis and in staging of postoperative cases of medulloblastomas, which was superior to postcontrast CT or precontrast MR.
Brain* ; Diagnosis ; Gadolinium DTPA ; Humans ; Male ; Medulloblastoma ; Necrosis ; Retrospective Studies ; Spine*

PURPOSE: The purpose of this study is to describe Magnetic Resonance(MR) findings of two epidural cavernous malformations of the spine. MATERIALS AND METHODS: MR imaging was performed in 2 patients(29-year-old man and 54-year-old woman). Sagittal T1 -, T2-weighted images and Gadolinium (Gd)-enhanced axial and sagittal images were acquired. Two patients had surgery and MR findings were compared with surgical and histopathological findings. RESULTS: MR imaging showed high- and low-signal intensity components of these lesions that were characteristic of an epidural cavernous malformation in one case. The other case showed a high signal intensity on T2- and strong enhancement on Gd-enhanced T1 -weighted images. We think that the former may be due to mixed subacute and chronic hemorrhage and the latter may be due to blood within the endotheliumlined sinusolds without hemorrhage. CONCLUSION: These findings were well correlated with the surgical and histo-pathological findings of cavernous malformation.
Gadolinium ; Hemorrhage ; Humans ; Magnetic Resonance Imaging* ; Middle Aged ; Spine*

No abstract available.
Nasal Cavity* ; Papilloma, Inverted* ; Paranasal Sinuses*

PURPOSE: To evaluate the relationship between spinal instability and ossification of the posteriorlongitudinal ligament(OPLL). MATERIALS AND METHODS: In 70 patients(M:F=45:25, mean age=53years) diagnosed as OPLLon the bosis of with surgical operation field findings and radiological evaluation[ plain film(n=70), CT(n=64),MRI(n=55) ], involved levels were the cervical spine(n=32), lumbar spine(n=23), and both the cervical and lumbarspine(n=15). Spinal instability was radiologically diagnosed as horizontal displacement of one vertebra by anotherof more than 3.5mm, or a difference in rotation from either adjacent vertebra by more than 11degree in lateralcervical spine and a difference of more than 1.5mm from the posterior body margins to the point of intersection oftwo lines drawn parallel to the opposing segmental endplate in extension lateral lumbar spine. We divided OPLLinto group I(continuous, segmental, mixed) and group II(retrodiscal), and compared spinal instability in these twogroups. RESULTS: In cervical OPLL, group I comprised 33 cases and group II 14. In group I, spinal instability wasnoted in 8/33 cases(24%)) or 10/123 segments(8.1%). Spinal instability in group II, on the other hand, was foundin 13/14 cases(93%) or 17/26 segments(65%). Ossification occurred at the retrodiscal level in 37 cases, byt incase was continuous. In group II, spinal instability was found in 25 of 37 cases(69%), oe in 29 of 55segments(53%). CONCLUSION: Compared to other types of OPLL, the frequency of retrodiscal OPLL in association withspinal instability was high. Spinal instability may thus be the most important cause of retrodiscal OPLL.
Hand ; Spine

Acute disseminated encephalomyelitis (ADEM) is a demyelinating disease of probable autoimmune etiology. The MR images of patients with clinically suspected ADEM were retrospectively reviewed. The clinical symptoms occurred 5 days to 1 month after viral upper respiratory infection (4) and Coxsakie viral infection(1). The symptoms had begun with fever(3), headache(3), sore throat(1), and drowsy mental state (1), which progressed with monophasic course to altered mental change(2), extremity weakness(2), seizure(1) and/or cerebellary symptom(I) MRI findings of ADEM showed patchy(4), nonhemorrhagic(5), asymmetric(5) high signal intensity lesions on T2-weighted images. The number of the lesions was mostly multiple(4). The lesions mainly involved the brain stem(3) and subcortical white matter(3). Follow-up MR images of 13 days to 20 days after high dose steroid therapy showed marked improvement in two of three, which well correlated with clinical manifestations. MR findin of multiple, patchy, nonhemorrhagic and asymmetric lesions in subcortical white matter and brain stem on T2-weighted images seem to be characteristic features of ADEM, but nonspecific. Therefore, clinical correlation is required in evaluating ADEM.
Brain ; Brain Stem ; Demyelinating Diseases ; Encephalomyelitis, Acute Disseminated ; Extremities ; Follow-Up Studies ; Humans ; Magnetic Resonance Imaging* ; Retrospective Studies ; White Matter

PURPOSE: A common finding of carotid artery on magnetic resonance angiograms(MRAs) is a signal dropout along the posterior wall of carotid bulb due to reverse flow. The purpose of this study is to evaluate variable flow patterns on bifurcated carotid arterial phantoms using steady-state flow. MATERIALS AND METHODS: We designed phantoms of a bifurcated carotid artery with acrylic materials. Flow patterns were evaluated with axial and coronal imaging of MRA(2D-TOF, 3D-TOF), color Doppler imaging, and computational fluid dynamics (CFD) within the phantoms constructed of an automated closed-type circulatory system filled with 4% sugar solution. These findings were compared with findings obtained from normal volunteers. RESULTS: Axial 3D-TOF MRA images exhibited closer resemblance to the contour of the inner wall of phantoms when compared to coronal 2D-TOF MRA imaging. However, 2D-TOF MRA showed good contrast difference of signal intensities between forward flow area and reverse flow area. Dark zones with reduced signal intensities due to reversed flow were separated from the outer wall of the internal and external carotid arteries by a thin layer of forward flow along the wall on the source slice image of MRA. The general hemodynamics of the phantoms on MRA were identical to hemodynamics on color Doppler imaging and CFD. The results obtained with the phantoms matched the findings on normal volunteers. CONCLUSION: Although representations of bifurcated carotid arterial phantoms on axial 3D-TOF MRA were excellent if ideally desinged, the zone of reversed flow could be a significant factor in creating distorted image when the zone of reversed flow contacted directly with curved or deformed arterial wall.
Carotid Arteries ; Carotid Artery, External ; Healthy Volunteers ; Hemodynamics ; Humans ; Hydrodynamics ; Magnetic Resonance Angiography* ; Patient Dropouts

PURPOSE: Pilocytic astrocytoma is a benign tumor predominantly arising from cerebellum in pediatric age. But it occasionally arises in supratentorium. We describe radiologic findings of supratentorial pilocytic astrocytoma. MATERIALS AND METHODS: Eleven CT and 7 MR examinations in 11 patients were retrospectively reviewed with attention to location, CT density, MR signal intensity, and degree and pattern of contrast enhancement on CT and MR. RESULTS: The tumors were located around the third ventricle (hypothalamus in three cases, optic chiasm in three cases) and in cerebral hemisphere (temporal lobe in three cases, frontal lobe in one case, thalamus in one case). On CT, the tumors were all sharply demarcated and rarely associated with edema. The tumors showed moderate to strong contrast enhancement. Necrosis appeared frequently in tumors around the third ventricle in contrast to frequent cyst formation in hemispheric masses. On MR, the tumors appeared hypo- or isointense on T1- weighted images and hyperintense on T2- weighted images. After administration of contrast agent, the tumors showed intense enhancement more than that of CT. CONCLUSION: The typical location and radiologic findings described above are helpful in the diagnosis of the supratentorial pilocytic astrocytoma.
Astrocytoma* ; Cerebellum ; Cerebrum ; Diagnosis ; Edema ; Frontal Lobe ; Humans ; Necrosis ; Optic Chiasm ; Retrospective Studies ; Thalamus ; Third Ventricle

Pleomorphic xanthoastrocytoma(PXA) is a benign brain tumor with favorable prognosis in spite of its marked pleomorphism. We report a case with review of the literature. An eight-year-old boy presented with headache and vomiting. Plain skull X-ray showed findings of increased intracranial pressure. The MR imaging demonstrated superficially located large cystic mass with a Iobulated mural nodule in the left frontal lobe. The mural nodule abutting leptomeninges showed intense enhancement on postcontrast Tl-weighted images, but the cyst wall was not enhanced. Preoperative diagnosis of PXA with the MRI findings could lead to avoidance of more aggressive brain resection and therefore more favorable neurological outcome
Brain ; Brain Neoplasms ; Child* ; Diagnosis ; Frontal Lobe ; Headache ; Humans ; Intracranial Pressure ; Magnetic Resonance Imaging ; Male ; Prognosis ; Skull ; Vomiting

Intraspinal neurenteric cysts are rare congenital lesions that results from abnormal separation of germ layers in the third week of embryonic development, which may cause spinal compression. Although, the diagnosis of neurenteric cyst was very difficult prior to operation, MRI has proven to be a useful imaging modality in detection, localization and characterization of intraspinal neurenteric cysts. We recently experienced intraspinal neurenteric cyst in two patients who presented with progerssive quadriparesis. Myelography, CT myelography and MRI were taken and complete excision was performed. The MRI findings are presented and the literature is reviewed.
Diagnosis ; Embryonic Development ; Female ; Germ Layers ; Humans ; Magnetic Resonance Imaging* ; Myelography ; Neural Tube Defects* ; Pregnancy ; Quadriplegia

Pancreatic pseudocyst occurs as a complication of pancreatitis or trauma, which results in the escape of pancreatic enzymes from the parenchyma or ductal system of pancreas. At that time, serum amylase may have returned to normal level, and the patient may be subjectively asymptomatic. In this phase, the radiologic findings are relatively greater significance than laboratory data. In the conventional radiologic study, pancreatic pseudocyst have been frequently confused with other retroperitoneal mass, but recently with clinical application of ultrasound and CT scan, more accurate diagnosis can be obtained. The brief results are as follows; 1. Male to female ratio was 3:2 in 15 patients. Incidence was most common in young adult age. Most frequent symptom was epigastic pain, and which was noted in 11 cases of patients. 7 cases of patients had past history of abdominal trauma and past history of pancreatitis was only in 1 case. Most common laboratory finding was leukocytosis in 8cases of patients and elevated serum amylase was also noted in 7 cases. 2. In each 5 cases of patients, plain chest roentgenologic evidence of left side pleural effusion and hemidiaphragm elevation were observed. 3. On flat abdomen film, soft mass shadow was visualized in 8 cases of patients. On UGI series, evidence of retrogastric space widening was observed in 11 cases of patients. 4. The location of pseudocyst is mainly in body and tail of pancrease in 11 cases of patients. 5. More accruable diagnosis can be obtained through application of ultrasound and CT scan.
Abdomen ; Amylases ; Diagnosis ; Female ; Humans ; Incidence ; Leukocytosis ; Male ; Pancreas ; Pancreatic Pseudocyst ; Pancreatitis ; Pancrelipase ; Pleural Effusion ; Tail ; Thorax ; Tomography, X-Ray Computed ; Ultrasonography ; United Nations ; Young Adult