Utility of Intraprocedural Contrast-Enhanced CT in Ablation of Renal Masses.

OBJECTIVE. The purpose of this study was to evaluate the efficacy of radiofrequency ablation (RFA) of renal masses comparing a group who did not undergo intraprocedural CT and a group who did. MATERIALS AND METHODS. A retrospective review included 45 consecutively registered patients who underwent RFA of renal masses. If an adequate biopsy specimen was not obtained or follow-up was inadequate, the patient was eliminated from review from calculation of primary technical efficacy. The inclusion criterion was having undergone RFA with two cooled-tip electrodes. Baseline demographics (age, body mass index, and sex), renal mass characteristics (diameter, side, location, position, morphologic features, type of mass, and grade), technical details (repositioning and hydrodissection), and complications were evaluated. Follow-up images were evaluated to determine the presence of recurrence at the ablation site in the two groups. RESULTS. Among the 45 patients who underwent RFA, 13 did not undergo intraprocedural CT and 32 intraprocedural did. Thirty-five patients met the criteria for follow-up and positive biopsy results. For calculation of recurrence, 10 patients were in the group who did not and 25 were in group who did undergo intraprocedural contrast-enhanced CT. No correlation was found between baseline demographics, renal mass characteristics, and technical results of the two groups. There was an 89% overall technical efficacy rate with a 96% primary technical efficacy rate in the group who underwent intraprocedural CT compared with a 70% rate in the group who did not undergo intraprocedural CT. Negative correlation was found between the groups with respect to technical efficacy rate at p < 0.05. CONCLUSION. Intraprocedural contrast-enhanced CT yields important information about completeness of ablation during the procedure, allowing probe repositioning and thus better therapeutic effect.

Portal Vein Thrombosis: Imaging the Spectrum of Disease With an Emphasis on MRI Features.

OBJECTIVE: The purpose of this article is to review the classic and uncommon imaging findings of portal vein thrombosis (PVT) (acute, chronic, congenital, and septic thrombus) as visualized on multiple modalities, with an emphasis on MRI findings. Additional aims are to understand the imaging of obliterative portal venopathy and its clinical significance, appreciate morphologic changes of the biliary system that may accompany PVT, and recognize changes in liver enhancement patterns seen with PVT related to the hepatic arterial buffer response. The review also addresses morphologic changes of the liver that may occur after PVT, including nodular regenerative hyperplasia, central hepatic hypertrophy, and peripheral fibrosis that may stimulate cirrhosis, as well as the importance of portal vein mapping and the diagnostic findings and clinical significance of tumor within the portal vein in the liver transplant population. CONCLUSION: PVT may be a complication of liver cirrhosis, but it may also occur as a primary vascular disorder without liver disease. PVT can result in portal hypertension and may present with variceal bleeding or hypersplenism. Radiologists should be familiar with the imaging of PVT in patients of various ages and in different clinical scenarios. PVT can influence hepatic perfusion, the shape of the bile ducts, and liver architecture. Bland PVT and tumor-related PVT have major implications for hepatic transplant.