ABSTRACT
Objective To investigate the role of contrast enhanced ultrasound (CEUS) in evaluating and guiding radiofrequency ablation (RFA) of hepatocellular carcinoma (HCC) and its feeding vessels. Methods From January 2006 to June 2007, 71 patients with 75 hypervascular HCC in Peking University Cancer Hospital who underwent RFA were included in the study. The diagnosis was conifrmed by ultrasound guided biopsy for all patients. These patients were not suitable for transcatheter arterial chemoembolization (TACE) or had poor responds to TACE. They were divided into two groups, which included group percutaneous artery ablation (PAA) combining RFA and group RFA. There were 38 patients with 39 HCC in group PAA combining RFA and CEUS were used to identify the range of HCC inifltration. Firstly, PAA of the feeding vessels was conducted under the guidance of color doplor lfow imaging (CDFI). Then CEUS was performed to evaluate HCC perfusion after blocking the feeding vessels. Finally, the rest of the tumor was ablated by RFA. In group RFA, there were 33 patients with 36 HCC, who did not undertake PAA before RFA. Generally, the RFA was planned based on tumor size and location, and the ablation started with deep part of HCC or portion close to nearby organs. Contrast CT was used as a post-RFA imaging for follow-up at 1, 3 and 6 months post-RFA. T test was used to compare the difference in focal lesions number between two groups, andχ2 tests were used to compare the difference in necrosis rate between two groups after treatment. Results In group PAA combining RFA, post-PAA CEUS showed intratumor perfusion decreased more than 70%in 31 HCC (79.5%, 31/39). Of them, 13 HCC (33.3%, 13/39) showed complete perfusion defect with clear margin, called“solar eclipse sign”. The rest 8 HCC (20.5%, 8/39) showed 40%-70%of perfusion defect. In group PAA combining RFA, CDFI showed 35 (83.3%, 35/42) feeding vessels were blocked, and 3 vessels (7.1%, 3/42) showed signiifcant decreased lfow signal after PAA. There were average 3.18±1.42 ablations per HCC in group PAA combining RFA, and 4.32±1.56 in group RFA. The number of ablations per HCC in group PAA combining RFA was signiifcantly less than group RFA (t=2.524, P=0.015). The tumor necrosis rate at 1 month post-RFA in group PAA (92.3%, 36/39) combining RFA was signiifcantly higher than that of group RFA (66.7%, 24/35) (χ2=8.264, P=0.001). Conclusions With CEUS, PAA can effectively block the feeding vessels of HCC, enhance ablated necrosis in the tumor and signiifcantly increase necrosis rate post-RFA for large hypervascular HCC. CEUS-assisted PAA can improve efifciency of RFA with less ablation number and better result.