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.

CT findings of retroperitoneal neurilemoma

No abstract available.

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.

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.

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.

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.

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.

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.

Radiologic Features of Posterior Fossa Hemangioblastomas: Emphasis on MR Findings

PURPOSE: To review MR findings of the posterior fossa hemangioblastomas and to evaluate diagnostic value of MRI correlated with CT and anglographic findings. MATERIALS AND METHODS: The MR findings in twelve patients with surgically proven posterior fossa hemangioblastomas including one case of von Hippel- Lindau disease were retrospectively analyzed and correlated with CT (7 patients) and anglographic findings (9 patients). RESULTS: On MRI, five hemangioblastomas were located in the cerebellar hemisphere and seven in the vermis. The masses appeared to be solid in 3 cases(25%), solid tumors with central cyst in 2 cases(17%), and cyst with mural nodules in 7 cases(58%). Abnormal tumor vessels represented by characteristic signal voids on MRI were observed in 9 cases(75%) and were not seen in 3 cases(25%) with mural nodule below 1.5cm in diameter. On pre-contrast CT, hemangioblastomas appeared poorly marginated slightly hyperdense masses in solid tumors, and hypodense cystic masses in cysts. After contrast enhancement, solid tumors were markedly enhanced, but it was difficult to differentiate hemangioblastomas from other tumors. In nine patients, anglograms demonstrated hypervascular blush corresponding to the solid component of the tumors. CONCLUSION: MRI was superior to CT in evaluating the characteristic of abnormal tumor vessels and mural nodules, delineation of tumor margin and tumor extent. Angiography was useful in the diagnosis of cystic hemangioblastomas which contain small mural nodule (less than 1.5cm in diameter) without definite vascular signal voids on MRI. MRI demonstrated solid or cystic tumor with small mural nodule and abnormal vascular signal voids in the posterior fossa should suggest hemangioblastoma.

CT and MRI Findings of Malignant Meningiomas: Comparison with Benign Meningiomas

PURPOSE: The purpose is to evaluate the CT or MRI findings to help in the differentiation between benign and malignant meningiomas. MATERIAL AND METHODS: The CT and MRI findings of 8 patients with surgically proven malignant meningioma were reviewed. Four cases of 8 malignant meningiomas and 18 cases of 27 benign lesions were studied with a 1.5T or 0.5T MRI. Radiologic analysis was focused on the heterogeneity of tumor, grade of peritumoral edema, presence of cystic degeneration and calcification, tumoral enhancement pattern, dural enhancement, and tumoral border. RESULT: Histologic types of malignant meningioma were meningotheliomatous (n=4), papillary(n=1), fibroblastic(n=l), angioblastic(n=l), and sarcomatous(n=l). Tumoral Heterogeneity was seen in 8 of 8 malignant lesions(100%) and 8 of 27 benign ones(30%). (p<0.01) Marked peritumoral edema was seen in 8 of 8 malignant lesions(100%) and 2 of 27 benign ones. (7.3%)(p<0.01) Most of malignant lesions(6 of 8 cases, 75%) showed ill defined border. Calcification was not present in malignant lesions in contrast with benign ones (14 of 27 cases, 52%). (p<0.05) No statistical significance was noted in cystic degeneration, dural tail like enhancement or tumoral enhancement pattern between malignant and benign meningiomas. MRI signal intensity of malignant meningiomas was homogeneously or heterogeneously hypointense on T1WI, heterogeneously isointense or hypointense on T2WI and heterogeneous or mixed on Gd-DTPA enhancement study. CONCLUSION: The CT or MRI findings such as heterogeneity, ill defined tumoral border, marked peritumoral edema, and absence of calcification may suggest the possibility of malignancy in meningioma.

Takayasus Arteritis with Pregnancy Induced Eclampsia / 대한뇌혈관학회지

We experienced a case of Takayasus arteritis with eclampsia in a 43-year-old woman. The patient had angiographically definite Takayasus arteritis with the involvement of right common and internal carotid arteries. On MR images performed at clinical manifestations of eclampsia, unilateral involvement of T2 high signal intensities were demonstrated in right cerebral hemisphere. We report this case with a literature review.

CT and MRI Findings of 4th Ventricular Tumors

PURPOSE: The purpose of our study is to evaluate characteristic features of 4th ventricular tumors in CT and MRI. MATERIALS AND METHODS: Pathologically proved 9 patients with 4th ventricular tumor were examined by CT and/or MRI. 4th ventricular tumors were epedymoma(4 cases), medulloblastoma(2 cases), choroid plexus papilIoma(2 cases), and oligodendroglioma(1 case). Included in our study were only those mass lesions that were located at surgery predominently within 4th ventricle with or without ventricular expansion. RESULTS: The origin of 4th ventricular tumor was the roof (epedymoma 3 cases, medulloblastoma 2 cases), the floor (epedymoma 1 case), and the undetermined(remaining 3 cases). On MRI, all tumors were hypointense exept ependymoma(3 cases) showing isointensity on T1WI. All tumors were hyperintense on PDWI and T2WI. On Gd-DTPA enhanced T1WI, strong enhancement was seen in all but epedymoma(1 case) which showed mild enhancement. On CT, as compared with MR images, various density on precontrast and postcontrast images were seen. Calcification was seen in choroid plexus papilloma(1 case) and oligodendroglioma(1 case). Hydrocephalus is seen in all cases exept ependymoma(2 cases) and oligodendroglioma(1 case). Hemorrhage within tumor was present only in epedymoma(2 cases). Cystic change or necrosis of tumor was seen in ependymomma(3 cases), choroid plexus papilloma(1 case), and oligodendroglioma(1 case). Peritumoral edema was seen in medulloblastoma(1 case). Extension through the foramen Luschka and the Magendie was seen in ependymoma(2 cases), choroid plexus papilloma(2 cases), and medulloblastoma(1 case). Seeding along the CSF pathway was seen only in ependymoma(2 cases). CONCLUSION: The results of our study may suggest that specific diagnosis of 4th ventricular tumor can be suggested preoperatively by analysing the origin in 4th ventricle, difference of CT density or MRI signal inten. sity, presence of extension or seeding through cerebrospinal fluid of the lesion.

Congenital External Auditory Canal Atresia and Stenosis: Temporal Bone CT Findings

PURPOSE: To determine the computed tomographic (CT) findings of atresia and stenosis of the external auditory canal (EAC), and to describe associated abnormalities in surrounding structures. MATERIALS AND METHODS: We retrospectively reviewed the axial and coronal CT images of the temporal bone in 15 patients (M:F=8:7; mean age, 15.8 years) with 16 cases of EAC atresia (unilateral n=11, bilateral n=1) and EAC stenosis (unilateral n=3). Associated abnormalities of the EAC, tympanic cavity, ossicles, mastoid air cells, eustachian tube, facial nerve course, mandibular condyle and condylar fossa, sigmoid sinus and jugular bulb, and the base of the middle cranial fossa were evaluated. RESULTS: Thirteen cases of bony EAC atresia (one bilateral), with an atretic bony plate, were noted, and one case of unilateral membranous atresia, in which a soft tissue the EAC. A unilateral lesion occurred more frequently on the right temporal bone (n=8, 73%). Associated abnormalities included a small tympanic cavity (n=8, 62%), decreased mastoid pneumatization (n=8, 62%), displacement of the mandibular condyle and the posterior wall of the condylar fossa (n=7, 54%), dilatation of the Eustachian tube (n=7, 54%), and inferior displacement of the temporal fossa base (n=8, 62%). Abnormalities of ossicles were noted in the malleolus (n=12, 92%), incus (n=10, 77%) and stapes (n=6, 46%). The course of the facial nerve was abnormal in four cases, and abnormality of the auditory canal was noted in one. Among three cases of EAC stenosis, ossicular aplasia was observed in one, and in another the location of the mandibular condyle and condylar fossa was abnormal. In the remaining case there was no associated abnormality. CONCLUSION: Atresia of the EAC is frequently accompanied by abnormalities of the middle ear cavity, ossicles, and adjacent structures other than the inner ear. For patients with atresia and stenosis of this canal, CT of the temporal bone is essentially helpful in evaluating these associated abnormalities.

CT Findings of Malignant Nasal Cavity Tumors

PURPOSE: To evaluate the CT finidngs of malignant nasal cavity tumors. MATERIALS AND METHODS: Retrospective analysis was performed on 20 patients with pathologically-proven malignant nasal cavity tumors. Using CT, we analysed their location, extent of bone destruction and of involvement of adjacent structures, and enhancing pattern. RESULTS: A total of 20 cases included nine squamous cell carcinomas, three olfactory neuroblastomas, three lymphomas, two polymorphic reticulosis, one adenoid cystic carcinoma, one undifferentiated carcinoma and one metastasis from renal cell carcinoma. All cases except one adenoid cystic carcinoma and one squamous cell carcinoma revealed bone destruction or erosion. Aggressive bone destruction and irregular enhancement were seen in eight cases of squamous cell carcinoma, seven cases of which showed involvement of the adjacent paranasal sinuses, nasopharynx, and orbit. Olfactory neuroblastomas were centered in the superior nasal cavity and the adjacent ethmoid sinus, and had erosion or destruction of the cribriform plate had occurred. Lymphomas showed bilateral involvement, with uniform contrast enhancement. Polymorphic reticuloses showed perforation or erosion of the nasal septum with bilateral involvement of the nasal cavity. CONCLUSION: The location, presence of bone destruction, involvement of adjacent structures, and enhancement pattern of tumor on CT can be helpful for the differential diagnosis of malignant nasal cavity tumors.

MRI Findings of Hydroxyapatite Orbital Implants

PURPOSE: To assess MR findings of hydroxyapatite orbital implants and their usefulness for the evaluation of fibrovascular ingrowth. MATERIALS AND METHODS: MR images of 32 hydroxyapatite orbital implants were obtained six months after implantation surgery. We retrospectively analysed MR images for signal intensity and contrast enhancement in both central and peripheral zones of the implants. The degree of contrast enhancement in an implant was compared with that of the temporalis muscle on contrast enhanced fat suppressed T1 weighted images. RESULTS: On T1-weighted images, implants showed a higher signal intensity than that of the vitreous body in the opposite globe. All implants showed peripheral contrast enhancement, densely enhanced in 30 cases and faintly in two. Three implants showed dense central contrast enhancement, and in the remainder, enhancement was similar to that of gray matter. On T2 weighted images, bright signal intensity was noted in 29 implants, focally in 19 and diffusely in ten. In most cases, areas of peripheral iso- to low signal intensity on T2-weighted images corresponded well with the contrast-enhanced area on T1 weighted images. CONCLUSION: At six months ofter surgery, Gd-enhanced MR imaging was useful for the evaluation of fibrovascular ingrowth in hydroxyapatite orbital implants.

Stereotactic Radiosurgery of 26 Intracranial Arteriovenous Malformations with Linear Accelerator / 대한치료방사선과학회지

From July 1988 through November 1991, 26 patients with inoperable arteriovenous malformations were treated with 6 MV linear accelerator at the Kangnam St. Mary's Hospital, Catholic University Medical College. There were 5 females and 21 males with median age of 29 years (range: 6~63 years) and median follow up times of 15 months (range: 4~40 months). The arteriovenous malformation volumes treated ranged from 1 cm diameter to 3.5 cm rectangular size. The prescribed doses at the isocenter varied from 15 to 30 Gy and were given as a single fraction. To date, all patients performed follow-up not only clinically but also through CT or angiography based radiologic modalities every 6 month. A complete obliteration was achieved in 6 (23%) and partial obliteration in 8 (31%) and no change in 1 (4%). We observed 14 (54%) responsiveness of arteriovenous malformations after radiosurgery by 2 years afterward. Whereas, the decision of the remaining 11 (42%) patients was considered too early to expect the therapeutic response following radiosurgery. No complications through treatment related were observed, yet. Our initial outcome in these first 25 patients with arteriovenous malformations is recommended further follow-up.

MR Findings of Fibrous Dysplasia

PURPOSE: To describe the MR findings of fibrous dysplasia. SUBJECTS AND METHODS: MR images of fibrousdysplasia in 13 pathologically proved cases were retrospectively analyzed regarding the signal intensity, hypointense rind, internal septations, cortical disruption, soft tissue extension, and the pattern of contrast enhancement. RESULTS: All cases showed low signal intensity on T1-weighted images. On T2-weighted images, 8cases(62%) were hyperintense and 5 cases(38%) hypointense. Hypointense rind was seen in 10 cases(77%), internal septations in 3 cases(23%), and cystic change in 2 cases(15%). Soft tissue extension was observed in fourcases(31%) including one case with pathologic fracture. After Gd-DTPA infusion, central contrast enhancement wasnoted in 8 cases(73%) and peripheral rim enhancement in 3 cases(23%). Pathologically, hypointensity on T2-weighted images was due to numerous bony trabeculae. CONCLUSION: Hypointensity on T1W1 and hyperintensity(62%) or hypointensity(38%) on T2W1 as well as contrast enhancement in fibrous dysplasia depend on degree of cellularity, collagen, cystic and hemorrhagic changes, and bony trabeculae.

Unusual Acute Encephalitis Involving the Thalamus: Imaging Features

OBJECTIVE: To describe the brain CT and MR imaging findings of unusual acute encephalitis involving the thalamus. MATERIALS AND METHODS: We retrospectively reviewed the medical records and CT and/or MR imaging findings of six patients with acute encephalitis involving the thalamus. CT (n=6) and MR imaging (n=6) were performed during the acute and/or convalescent stage of the illness. RESULTS: Brain CT showed brain swelling (n=2), low attenuation of both thalami (n=1) or normal findings (n=3). Initial MR imaging indicated that in all patients the thalamus was involved either bilaterally (n=5) or unilaterally (n=1). Lesions were also present in the midbrain (n=5), medial temporal lobe (n=4), pons (n=3), both hippocampi (n=3) the insular cortex (n=2), medulla (n=2), lateral temporal lobe cortex (n=1), both cingulate gyri (n=1), both basal ganglia (n=1), and the left hemispheric cortex (n=1). CONCLUSION: These CT or MR imaging findings of acute encephalitis of unknown etiology were similar to a combination of those of Japanese encephalitis and herpes simplex encephalitis. In order to document the specific causative agents which lead to the appearance of these imaging features, further investigation is required.