Objective: Radiofrequency ablation (RFA) is one of major therapeutic options for hepatocellular carcinoma (HCC). Microbubbles appearing during RFA procedure make it difficult to detect the target clearly in ultrasonography (US) imaging. We developed a novel US-volume system, in cooperation with Hitachi Medical Corporation and Osaka Medical Center, to show the past US-data simultaneously with the real-time image during RFA to avoid the unnecessary additional FRA sessions by being visualized extent of tumor necrosis (margins) in this system. We assessed the effectiveness of the system.
Methods: This system displays multiplanar reconstruction (MPR) images providing a synchronized view with a US image along with past US-volume data in real time side-by-side on a personal computer. Forty seven nodules were treated by RFA using this system (US-volume group) and compared to 47 nodules treated before development of our system (control group). All targets were clearly depicted by US before RFA procedure. The margin was judged by dynamic computed tomography and complete response was defined when we observed with 5mm margin all around the target lesions.
Results: In the US-volume group, the average tumor size was same as that of control (15.9±4.9mm vs. 16.0±4.3mm), whereas the number of lesions with adequate margins were larger than that of control (95.7% vs. 74.5%). Moreover, number of RFA sessions was smaller in the US-volume group (1.03±0.17 vs. 1.12±0.32; P<0.01).
Conclusion: This system facilitates the recognition of necessary margins during RFA procedure, that resulted in the reducing number of RFA sessions and increasing rate of the successful therapy.