In Kyu Yu

Undifferentiated embryonal sarcoma of the liver: US and CT findings

Six cases of undifferentiated embryonal sarcoma (UES) were reviewed to determine their characteristic features on ultrasonography (US) (n=5) and computed tomography (CT) (n=6). US demonstrated a single large, echogenic mass with some anechoic spaces. Contrast-enhanced CT scan revealed a well-demarcated low-attenuation mass with hyperdense septations of variable shape and thickness. Discrepancy of internal architecture on US and CT was one of the important characteristics of UES. CT numbers were 25–47 HU in low-attenuation areas. Enhancing peripheral rim was found in four cases and some solid portions at the periphery or adjacent to the septa were found in all cases. Two patients who had follow-up US and CT without treatment showed enhancing solid portions, changing to hypodense as the tumor grew. When compared with the pathologic findings, US showed a more accurate representation of internal architecture than did CT. Familiarity with these US and CT findings of UES of the liver will be helpful in the differential diagnosis of primary hepatic tumors in childhood.

Usefulness of Single Voxel Proton MR Spectroscopy in the Evaluation of Hippocampal Sclerosis

Objective The purpose of our study was to determine the ability of H-1 MR spectroscopy (MRS) to lateralize the lesion in patients with hippocampal sclerosis. Materials and Methods Twenty healthy volunteers and 25 patients with intractable temporal lobe epilepsy whose MR imaging diagnosis was unilateral hippocampal sclerosis were included. This diagnosis was based on the presence of unilateral atrophy and/or high T2 signal intensity of the hippocampus. Single-voxel H-1 MRS was carried out on a 1.5-T unit using PRESS sequence (TE, 136 msec). Spectra were obtained from hippocampal areas bilaterally with volumes of interest (VOIs) of 6.0 cm3 and 2.25 cm3 in healthy volunteers, and of either 6.0 cm3 (n = 14) or 2.25 cm3 (n = 11) in patients. Metabolite ratios of NAA/Cho and NAA/Cr were calculated from relative peak height measurements. The capability of MRS to lateralize the lesion and to detect bilateral abnormalities was compared with MR imaging diagnosis as a standard of reference. Results In healthy volunteers, NAA/Cho and NAA/Cr ratios were greater than 0.8 and 1.0, respectively. In patients, the mean values of these ratios were significantly lower on the lesion side than on the contralateral side, and lower than those of healthy volunteers (p < .05). The overall correct lateralization rate of MRS was 72% (18/25); this rate was lower with a VOI of 6.0 cm3 than of 2.25 cm3 (64% versus 82%, p < .05). Bilateral abnormalities on MRS were found in 24% (6/25) of cases. Conclusion Although its rate of correct lateralization is low, single-voxel H-1 MRS is a useful and promising diagnostic tool in the evaluation of hippocampal sclerosis, particularly for the detection of bilateral abnormalities. To improve the diagnostic accuracy of H-1 MRS, further investigation, including the use of a smaller VOI and measurement of the absolute amount of metabolites, are needed.

MRI features of choroid plexitis

Abstract Four cases of choroid plexitis of the brain (two with cryptococcosis and two with tuberculosis) are presented. The four patients showed either unilateral enlargement (3) or bilateral enlargement (1) and dense enhancement of the choroid plexus in the lateral ventricles (4) and fourth ventricle (1) in association with clinical findings of leptomeningitis. All patients had unilateral cystic dilatation of the temporal horn of the lateral ventricle presumably secondary to entrapment of the temporal horn and extensive oedema around the ipsilateral ventricle.

Imaging Findings of Osler-Weber-Rendu Disease Involving the Liver

Osler -Weber -Rendu disease or hereditary hemorrhagic telangiectasia(HHT) has been known to be an autosomal dominant disorder characterized by telangiectases and arteriovenous malformations of multiple organ systems(1). Hepatic involvement occurs in 8-31 % ofcases with HHTand includes telangiectases or arteriovenous fistulas associated with fibrosis and cirrhosis(2 , 3). Recent reports demonstrate various imaging findings including Doppler sonography with color flow signals , CT, and MR findings of the liver involvement in patients with HHT(2 -4). A few cases with HHT had reported in Korea(5). We describe the findings of conventional and Doppler sonography, and computed tomogram(CT) in a case with HHT involving the liver