Pattern Analysis of False Positive Findings of Spiral CT Hepatic Arteriography

PURPOSE: To evaluate the patterns of pseudo-lesions present on spiral CT hepatic arteriography (CTHA). MATERIALS AND METHODS: One hundred and seventy five patients (161 men and 14 women, aged 15-70 years [mean, 52 years]) who underwent spiral CTHA for the detection of hepatic lesions were retrospectively reviewed.Pseudo-lesion type was determined by comparing hyperattenuating lesions on CTHA with the findings of ultrasonography, conventional or multi-phase CT, Lipiodol CT, angiography, CT arterial portography(CTAP), and follow-up of spiral CTHA. Pseudo-lesions were classified according to site, size and shape. RESULTS: A total of 77 pseudo-lesions were found in 56 of the 175 patients(32.6%), and were classified into the following types :peritumoral(n=18), segment I(n=3), segment IV(n=3), gallbladder fossa (n=13), subsegmental (n=3), subcapsular(n=13), straight line sign (n=10), arterioportal shunt (n=13), and technical error (n=1). Fifteen of 77 pseudo-lesions(19.5%) showed hyperattenuation on CTHA and iso attenuation on CTAP, in contrast to adjacent liverparenchyma. CONCLUSION: In patients with hepatic mass, it is very important to understand the characteristicsite, shape and size of pseudo-lesions for the correct interpretation of CT and subsequent management of thepatient.

Evaluation of Hepatic Atrophy after Transcatheter Aterial Embolization

PURPOSE: Hepatic atrophy has been recognized as a complication of hepatic and biliary disease but we have often found it in follow up CT after transcatheter arterial embolization {TACE). The purpose of this study is to evaluate the characteristics of hepatic atrophy after TACE. MATERIAL AND METHODS: Of 53 patients who had TACE, We evaluated the relationship between the incidence of hepatic atrophy and the number of TACE, and also evaluated the average number of TACE in patients with hepatic atrophy. Of 20 patients who had received more than average number of TACE for development of hepatic atrophy (2 times with portal vein obstruction, 2.7 times without portal vein obstruction in this study), we evaluated the relationship between the tipiodol uptake pattern of tumor and the incidence of hepatic atrophy. RESULTS: There were 8 cases of hepatic atrophy (3 with portal vein obstruction, 5 without portal vein obstruction), average number for development of hepatic atrophy were 2.5 times. As the number of TACE were increased, the incidence of hepatic atrophy were also increased. Of 20 patients who received more than average number of TACE for development of hepatic atrophy, we noted 6 cases of hepatic atrophy in 11 patients with dense homogenous lipiodol uptake pattern of tumor and noted only 1 case of hepatic atrophy in 9 patient with inhomogenous lipiodol uptake pattern. CONCLUSION: Hepatic atrophy was one of the CT findings after TACE even without portal vein obstruction. Average number of TACE was 2.5 times and risk factors for development of hepatic atrophy were portal vein obstruction, increased number of TACE, and dense homogenous lipiodol uptake pattern of tumor.

MRI Findings of Hemangioblastomas

PURPOSE: The purpose of this study is to evaluate the findings of magnetic resonance imaging(MRI) of posterior fossa hemangioblastoma and usefulness of contrast enhancement with Gd-DTPA. MATERIALS AND METHODS: Seven patients with posterior fossa hemangioblastoma were studied with both pre- and post-enhanced MRI. The MR images were reviewed regarding the location, size, signal intensities of cysts and mural nodules, and their contrast enhancement pattern. RESULTS: Five tumors were located in cerebellar hemisphere, one in vermis, and one in posterior part of medulla. One patient with von HippeI-Lindau disease had a medullary hemangioblastoma with multiple pancreatic cysts. In 6 cases, the major portion of the tumor was cysts and had small mulkal nodules. The solid portion was relatiely lange in one case, cemprising half of the tumor Cysts were oval shaped and their sizes were 3--6.7cm in diameter. In five cases(71%), septations were noted within the cysts. Cysts were isointense or slightly hyperintense on Tl-weighted image and hyperintense on T2-weighted image compared with cerebrospinal fluid. Mural nodules were oval or rounded appearance in five cases and flattened appearance in two, and their size was 0.5--2.5cm in diameter. Mural nodules were isointense to gray matter. They were detected in five cases on Tl-weighted images and one case on T2-weighted images. In two cases, vascular signal void area was noted in mural nodules. On contrast-enhanced Tl-weighted images, all mural nodules were intensely enhanced. CONCLUSION: MRI proved to be a good diagnostic method to detect and characterize posterior fossa hemangioblastoma. The most common finding is Cystic posterior fossa lesion with enhancing mural nodule. Contrast enhancement is essential for specific diagnosis.

Percutaneous Abscess Drainage of Multiloculated Liver Abscess

PURPOSE: Recently there have been some reports that percutaneous absces drainage(PAD) was ineffective in treating multiloculated liver abscess. We therefae, reviewed our results of catheter drainage in jultiloculated liver absces. MATERIALS AND METHODS: PADs in 10 cases of multiloculated liver abscesses were performed with 8.5F Pig tail, 12 & 14F Sump cahteters, under ultrasonic & fluoroscopic guidance. RESULTS: All the 10 cases were successfully drained without major complications. Mean drainage duration was 16.3 day and the result was not significantly different from those obtained by draining unilocular pyogenic liver abscess. The success was the result of using large caliber catheter and repetition in insertion of guidewire deeply into abscess cavity to make communications between the Iocules which was proven by abscessogram. CONCLUSION: PAD was safe and effective method for multiloculated abscess as unilocular liver abscess, and it is recommended that the multiloculated liver abscess be draincd.