Hak Soo Kim

Intrerenal pseudoaneurysms complicating renal choriocarcinoma metastases: treatment with coil embolization

Most intrarenal pseudoaneurysms result from a laceration of the renal artery or its branches. However, tumor-induced renal pseudoaneurysm is very rare. We report a case in which embolization of an intrarenal pseudoaneurysm complicating renal metastases resulting from a choriocarcinoma was successful.

Utility of MR Cholangiography for Follow-up Examination after Metallic Stent Placement in the Bile Duct

Purpose: To evaluate the efficacy of MR cholangiography for follow-up examination after metallic stent placement in the bile duct. Materials and Methods: Between December 1999 and June 2000, 15 patients with biliary obstruction in whom metallic biliary stents had been placed underwent MR cholangiography during follow-up examination. The causes of obstruction were hilar cholangiocarcinoma (n=6), common bile duct cancer (n=5), gall bladder cancer (n=1) and pancreatic cancer (n=3). The types of self-expandable metallic stent employed were the nitinol stent (n=2), the Endocoil nitinol stent (n=3), the Ultraflexed Diamond stent (n=5), and the Wallstent (n=5). Using MR cholangiography, we measured the diameter of that part of the biliary stent which showed high signal intensity, assigning one point if this was less than one third of the stent diameter, two points if between one third and two thirds, and three points if more than two thirds. We decided that a higher score indicated fewer artifacts. Results: The score was 1.7-3 (mean, 2.3) points for the Endocoil nitinol stent, 1.7-2.3 (mean, 2) for the nitinot stent, and 1-3 (mean, 1.7) for the Ultraflex Diamond stant. In most cases, two thirds of the stent diameter was observed. For the Wallstent, the score was 1-1.7 (mean, 1.3) points and the inner portion of the stent was almost invisible. Conclusion: MR cholangiography is not useful for follow-up examination after the placement of Wallstents and three other types of nitinol stent in the bile duct.

Comparison of Non-Breath-Hold T2-weighted Turbo Spin-Echo and Three Breath-Hold T2-weighted MR Images for Detection of Focal Hepatic Lesion

Purpose : The purpose of this study was to compare non-breath-hold T2-weighted turbo spin-echo (TSE) MR imaging with three types of breath-hold T2-weighted MR imaging (breath-hold TSE [BHTSE], half-Fourier sin-gle- shot TSE [HASTE], and true-fast imaging with steady-state precession [FISP]) for hepatic lesion detection. Materials and Methods : T2-weighted MR images obtained using the above with the four sequences in 38 patients with 53 solid malignant and 90 non-solid benign hepatic lesions were retrospectively analyzed. Images were compared quantitatively (lesion-to-liver contrast-to-noise ratio and lesion detectability) and qualitatively (conspicuity of lesion and artifact). Statistical analysis involved the paired t-test for quantitative evaluation and Wilcoxon’s signed rank test for qualitative evaluation. Results : The values of lesion-to-liver contrast-to-noise ratios and lesion conspicuity for solid malignant hepatic lesions were better with non-breath-hold TSE imaging than with the three breath-hold T2-weighted sequences (p .05), and lesion detectability for non-solid benign lesions was similar (94% and 98%, compared with 91% and 96 %). Conclusion : In the cases of solid malignant hepatic lesions, the three breath-hold T2-weighted sequences were inferior to non-breath-hold TSE with regard to lesion-to-liver contrast-to-noise ratio and lesion detectability. Non-breath-hold TSE imaging should thus not be replaced by breath-hold T2-weighted imaging.

MR Imaging Findings of Renal Capsular Leiomyoma : A Case Report

In the literature, descriptions of the MR findings of renal leiomyoma are rare. We p-resent the MR findings ofa capsular leiomyoma of the kidney in which hy pointensity relative to normal renal parenchyma was seen on bothT1- and T2-weighted MR images.