Acute Obstructive Cholangitis after Transarterial Chemoembolization: the Effect of Percutaneous Transhepatic Removal of Tumor Fragment

Acute obstructive cholangitis due to the migration of necrotized tumor fragment is a rare complication occurring after a transarterial chemoembolization. The percutaneous tumor removal procedure following percutaneous transhepatic biliary drainage is an appropriate treatment over endoscopic removal for the relief of acute cholangitis in this case. Following this serial management, no invasive hepatocellular carcinoma of the bile duct recurred after two years of follow-up.

A Case Report of Periodic Alternating Nystagmus

A 19-year-old man with periodic alternating nystagmus (PAN) is presented. He reported that he had had oscillopsia and head oscillations for as long as he could remember. Acquired diseases associated with PAN were ruled out with various laboratory aids. This case is believed to be the first reported case of PAN in Korea.

CT findings of retroperitoneal neurilemoma

No abstract available.

Intraventricular Hemorrhage Caused by Lateral Ventricular Meningioma: A Case Report

Meningiomas causing intracranial hemorrhage are rare, and hemorrhage from a lateral ventricular meningioma seems to be even rarer. We report a case of trigonal meningioma in a 43-year-old woman who presented with intraventricular hemorrhage, and describe the CT, MRI and angiographic findings.

Diagnostic Value of MR Imaging in Differentiation of Meniscal Tear Patterns

PURPOSE: To evaluate the diagnostic accuracy of magnetic resonance (MR) imaging in the differentiation ofmeniscal tear patterns of the knee. MATERIALS AND METHODS: MR images of 93 patients with meniscal tear wereincluded in this study. On the basis of arthroscopic findings, the configuration of meniscal tears was classifiedas horizontal (n=44), longitudinal (n=34), transverse (n=11), or oblique (n=5). Oblique sagittal and coronal MRimages were obtained and com-pared with the arthroscopic findings. RESULTS: Among 94 cases ofarthroscopically-proven meniscal tears, 35 of 44 horizontal and 27 of 34 longitudi-nal configurations werecorrectly interpreted on MR images. Sensitivity and specificity for horizontal configu-ration were 80 % and 80 %,respectively, while the corresponding values for longitudinal configuration were 79 % and 95 %. On MR images, tworadial configurations were correctly interpreted from 11 confirmed tears and only one oblique configuration fromfive confirmed tears. CONCLUSION: MR imaging was useful for the differentiation of horizontal and longitudinaltears, but inaccurate in cases involving radial or oblique tears.

MR Imaging of Acute Necrotizing Encephalopathy:A Report of Two Cases

Acute necrotizing encephalopathy is the term used to describe acute encephalopathy with bilateral thalam-otegmental involvement that occurs in infants and children after febrile viral illness. We report the MR findings of two cases of this condition.

Benign Neoplasms of the Trachea: Case Reports

Benign tumors of the trachea are rare, accounting for approximately 10% of all primary tracheal neoplasms. They are frequently misdiagnosed and managed as bronchial asthma or chronic bronchitis. We report a lipoma and a leiomyoma of the trachea with emphasis on the clinical, radiographic and CT findings, and review the literature.

Benign Neoplasms of the Trachea: Case Reports

Benign tumors of the trachea are rare, accounting for approximately 10% of all primary tracheal neoplasms. They are frequently misdiagnosed and managed as bronchial asthma or chronic bronchitis. We report a lipoma and a leiomyoma of the trachea with emphasis on the clinical, radiographic and CT findings, and review the literature.

Usefulness of 2D PC MRA of the Circle of Willis in the Evaluation of Acute Cere b ral Infarction

PURPOSE: To evaluate the usefulness of axial 2-D PC MRA of the circle of Willis in the evaluation of acute cerebral infarction. MATERIALS AND METHODS: We evaluated 42 patients with acute cerebral infarction who had undergone T2 weighted and diffusion weighted MR imaging (T2WI, DWI) and 2-D PC MRA of the circle of Willis within 72 hours of the onset of symptoms. In conjunction with high-signal lesions on DWI, the findings of 2-D PC MRA were classified as normal, stenotic, or indicative of arterial occlusion; negative 2-D PC MRA was not considered useful. In addition, the signal intensity of T2WI and DWI was compared. RESULTS: (The findings of 2-D PC MRA showed that 15 cases (35.7%) were normal, 13(31%) were stenotic, and that in 14 (33.3 %), occlusion was present). Thus, 2-D PC MRA detected vascular abnormality in 27 cases (64.3 %). On T2WI, six cases (14.3 %) showed no signal change and 36 (85.7 %) showed high signal change. In six cases without signal change, MR images were obtained within 12 hours of ictus; in one of these patients MRA findings were normal, one had stenosis, and in four, occlusion was noted. CONCLUSION: 2-D PC MRA is a useful modality for the detection of vascular abnormality in patients with acute cerebral infarct.

Localized, water-suppressed in vivo H MR spectroscopy of human brain tumors: Preliminary results

Image-guided localized, water-suppressed in vivo 1H MR spectroscopic studies were performed on the brain tumors in 3 patients. In all 3 patients, in vivo 1H MR spectra in brain neoplastic tissues revealed that the signal intensities of N-acetylaspartate (NAA) choline (Cho) resonances were decreased and increased, respectively, comparing with healthy normal tissue. A distinct lactate signal was identified in all three patients. A ratio that the observed metabolite alterations from localized, water-suppressed in vivo 1H MR spectroscopy can be useful as an index of brain tumors, and that the technique is clinically to highlight as one promising modalities in brain tumors for more accurate diagnosis.

MR Distinction between Multiple Myeloma and Metastasis Involving the Spine

PURPOSE: To differentiate multiple myeloma from metastasis involving the spine at MR imaging. MATERIALS AND METHODS: Twenty-five patients with multiple myeloma and 37 with vertebral metastasis were included in this study. MR images were retrospectively analyzed with regard to infiltration and enhancement patterns, signal intensity, the involvement of three consecutive vertebrae, the number of lesions within one vertebra, and paraspinal and epidural masses. Using a 1.5-T imager, we obtained sagittal and axial, unen-hanced and enhanced T1-weighted images, and fast spin-echo images. For statistical analysis, Fisher's exact test was used. RESULTS: All cases of multiple myeloma and metastasis showed low signal intensity on T1-weighted images, and there were no significant differences in signal intensities or enhancement patterns. Infiltration and enhancement patterns were classified as focal (52% in multiple myeloma vs 68% in metastasis, p> 0.05), diffuse (32% vs 32%, p > 0.05) or salt and pepper (16% vs 0%, p 0.05), isoin-tensity (36% vs 3%, p 0.05). Paraspinal and epidural masses played little part. CONCLUSION: The salt and pepper infiltration pattern, the presence of more than five lesions within one vertebra, and the involvement of more than three consecutive vertebrae were useful MR findings for differentiation between multiple myeloma and metastasis involving the spine. In most cases, however, it is difficult to distinguish between the two conditions.

CT Findings of Spontaneous Subarachnoid Hemorrhage of Unknown Cause

PURPOSE: Spontaneous subarachnoid hemorrhage(S-SAH) is a relatively rare disease with good clinical course and prognosis. The purpose of this study is to evaluate the cisternal blood distribution on CT in patient with S-SAH. MATERIALS AND METHODS: Out of 406 patients with subarachnoid hemorrhage on brain CT scan, 11 patients confirmed to be S-SAH by angiography and clinical follow-up were examined. We analysed the CT findings of these 11 cases retrospectively. RESULTS: Five patients had only perimesencephalic distribution of hemorrhage:the prepontine, the interped- uncular, and the suprasellar cisterns were involved in 4 cases each, the basal sylvian cistern in 3 cases, and the ambient cistern in 2 cases. The quadrigeminal and a portion of the lateral sylvians were also involved in 1 case each. Six patients revealed cisternal hemorrhage extending beyond the perimesencephalic cistern into the ventricles, cortical sulci, and lateral sylvian fissure. Intraventricular hemorrhage was noted in 3 cases of these 6 patients. CONCLUSION: Our study suggests that uncomplicated clinical course and normal anglographic finding are more important than CT distribution of cisternal hemorrhage in diagnosing S-SAH.

Cavernous Hemangioma of the Cavernous Sinus: A Case Report

Intracranial extra-axial cavernous hemangioma of the cavernous sinus is a very rare vascular malformation. It usually appears as a round non-encapsulated mass with well-defined borders, mimicking meningioma. We describe a case of cavernous hemangioma of the cavernous sinus, including the radiologic imaging findings, and also review the literature.

Acute Spontaneous Subdural Hemorrhage by Cerebral Aneurysmal Rupture: Report of Two Cases

Two cases of acute spontaneous subdural hemorrhage caused by cerebral aneurysmal rupture are presented. The patients’ chief complaints were sudden bursting headache and comatose mentality. There was no history of trauma or proclivity for spontaneous bleeding, and CT scans of the brain indicated subdural hemorrhage without remarkable subarachnoid hemorrhage. In case 1, an aneurysm at the distal segment of the right anterior cerebral artery was identified by CT angiography; the subdural hemorrhage was evacuated and the aneurysm surgically clipped. In case 2, an aneurysm at the junction of the anterior communicating artery and the right anterior cerebral artery was revealed by CT angiography and digital subtraction angiography, and Guglielmi detachable coil embolization of the aneurysm was performed.

Stable Xenon-CT Cerebral Blood Flow Imaging in Patients with Cerebral nfarction

BACKGROUND: Stable xenon-CT has been known to be a useful technique for measuring cerebral blood flow (CBF) and its direct correlation with CT anatomy. We evaluated the usefulness and limitations of stable xenon-CT cerebral hemodynamic status. METHODS: Xenon-CT was administered to 23 patients. Ten were normal controls and 13 were stroke patients (acute 4, subacute 5, chronic 2, hemorrhagic 2). Time dependent Xenon concentrations within various tissue segments of the brain was used to derive both the local partition-coefficient (lamda) and CBF in each tissue volume (voxel) of the CT image. RESULTS: In the controls, the regional CBF (rCBF) (ml/100 gm/min) was as follows: frontal 22.9+/-7.3(Mean+/-SD), inferior temporal 23.9+/-3.2, superior temporal 27.4+/-7.3, parietal 30.0+/-10.1, occipital 24.3+/-8.4, cerebellar hemisphere 24.3+/-8.3, thalamus 31.1+/-7.1, and corona radiata 18.1+/-4.7. The cortical differences was within 10%. In the stroke patients, the rCBF in the infarcted area ranged from 0 to 26.5 ml/100 gm/min and interhemispheric cortical difference was above 50%. The routine CT revealed no abnormalitiy, particularly in acute stroke (within 6 hours after onset). However, a xenon-CBF showed perfusion defect which correlated with clinical signs. CONCLUSIONS: With xenon CT, CBF can be obtained within a few hours of stroke onset, result of which can be correlated with CT. In an acute stroke state, a Xenon-CBF map can be a more sensitive method than routine CT imaging. Low value of blood-flow and patient's in cooperation may limit use of Xe-CT.

Metabolic Alterations of Acute Cerebral Infarction Evaluated by Localized, Water-Suppressed In Vivo'H MRS

Localized, water-suppressed in vivo 'H MRS was performed to evaluated the proton metabolic alterations in patients with acute cerebral infarction.Ten brain infarction patients(six males and four females; age range 53-77) participated in this study. GE Signa 1.5-T whole-body NMI/MRS system using STEAM pulse sequence was used. Voxels were selected from the cerebral infarcted region and contralateral normal region as control in the same patient. Proton metaboliteratiosrelativetocreatine (Cr) wereobtainedusingaMa-rquartalgorithm. The specific features in the cerebral infarcted regions demonstrated a significant decrease of N-acetyl aspartate (NAA)/creatine (Cr) ratio, compared with control regions. Markedly increased lactate (Lac) level was observed in areas of cerebral infarctioln in all patients. Our preliminary study showed that NAA/Cr ratio in the infarcted regions was substanially different from that in control regions.The signal intensity of Lac may be served as a metabolic criterion that can specify acuteness of infarction, and also evaluate the therapeutic effect. It is necessary to investigate the spectral alterations in various stages of cerebral infarction for further detail analysis.

MRI Findings of Vermian Medulloblastoma

PURPOSE: To find characteristic MRI features of vermian medulloblastoma. MATERIALS AND METHODS: MRI studiesand medical records were retrospectively reviewed for 12 patients with surgically proven midline medulloblastoma. The assessment concerned appearance of the mass in relation to surrounding structures ; MR signal intensity ; the enhancement pattern ; the mass's location and size ; presence of a cystic/necrotic area, calcification, or vascular void ; extension through the foramen Luschka ; degree of hydrocephalus ; and presence of tonsillarherniation. RESULTS: The midline medulloblastoma commonly showed roundish moon-surface appearance, especially onthe axial T2-weighted images. All tumors showed heterogeneous signal intensities mainly due to intratumoralcystic/necrotic or hemorrhagic changes. The tumors were commonly located at mid- and/or inferior vermis. Occasionally the tumors extended through the foramen Luschka, and caused obstructive hydrocephalus of moderate tosevere degree. Post-con-trast study showed heterogeneous, dense contrast enhancement in the majority of patients. CONCLUSION: The MR finding of the moon-surface appearance formed by both the mass and the intratumoralcystic/necrotic change as seen on axial T2-weighted images could be helpful in the diagnosis of vermianmedulloblastoma.

CT and MR findings of neuronal migration anomalies

No abstract available.

Diffusion-weighted Imaging of Cerebral Ischemic Infarcts: Comparison with T2-weighted Imaging in Signal Intensity

PURPOSE: To investigate whether ischemic infarct can be staged by evaluating signal intensities on diffusionweighted (DWI) and turbo spin echo T2-weighted images(T2WI). MATERIALS AND METHODS: DWI and T2WI of 27 patientswith ischemic infarct were retrospectively evaluated. Infarcts were divided into five stages depending on time ofonset : hyperacute within 12 hours, acute between 12 hours and 3 days, subacute between 3 and 10 days, earlychronic between 10 and 30 days, and late chronic after 30 days. Signal intensities of these lesions compared withnormal brain on DWI and T2WI were visually evaluated and divided into six patterns. Pattern 1 included high signalon DWI and iso-signal on T2WI, pattern 2 showed high signal on both DWI and T2WI with higher contrast on DWI,pattern 3 showed the same high signal on both images; pattern 4 revealed high signal on both images with highercontrast on T2WI, pattern 5 showed iso-signal on DWI and high signal on T2WI, and pattern 6 revealed low signal onDWI and high signal on T2WI. These five clinical stages and six MRI patterns were correlated in each patient. RESULTS: Six cases were hyperacute, six were acute, eight were subacute, three were early chronic, and four werelate chronic. At the hyperacute stage, five cases showed pattern 1 (83%) and one case, pattern 2. At the acutestage, all six cases showed pattern 2. At the subacute subcute stage, seven cases showed pattern 2(87.5%) and onecase pattern 4. At the early chronic stage, two cases showed pattern 2(66.7%) and one case, pattern 5. At the latechronic stage, all cases showed pattern 6. CONCLUSION: DWI is useful for the detection of early ischemic infarct,and stages of ischemic infarcts can be estimated by evaluating signal intensities on DWI and T2WI.

MRImaging of Solid Cerebellar Tumors in Adult

PURPOSE: The solid variety of cerebella r tumors in adult is relatively uncommon. This study is to describe the characteristic MR findings of various solid cerebellar tumors in adult. METHODS: Twenty three cerebellar solid tumors from 22 consecutive patients over age of 15 with surgical confirmations were retrospectively evaluated with MR imaging. H istologic diagnosis included hemangioblastoma (n=6), metastasis (n=6), high-grade astrocytoma (n=3), and medulloblastoma (n=8). The MR findings were reviewed with attention to the size, the signal intensity of the tumors, pattern of enhancement, tumoral margin, degree of peritumoral edema, signal void vascular structures within and/or around the tumor, and location in relation to attachment to the pial surface of the tumor. RESULTS: Solid hemangioblastomas consistently showed slightly low or iso signal intensity on T1 -weighted images and high intensity on T2-weighted images, dense homogeneous enhancement, and signal void vessels within and/or around the mass. Metastatic tumors showed various find ings with predominantly low or iso signal intensity on T2-weighted images. Medulloblastomas was midline and/or paramidline in location, and had larger mass formation. High-grade astrocytomas revealed nonspecific MR findings with no signal void vessels. CONCLUSION: Hemangioblastoma, metastasis, malignant astrocytoma, and medulloblastoma should be included in differential diagnosis of solid cerebellar tumors in adult. Dense homogeneous enhancement and signal void vessels are characteristic of hemangioblastoma. The signal intensity of the tumor, and presence of signal void vessels, location and enhancement pattern can be some value in differential diagnosis of solid cerebellar tumors in adult.