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Abstract

Background: During RFA, microbubbles can be observed by ultrasound. Microbubbles are thought to represent steam generated by rapidly heated tissue. Therefore, we used an angioscope to observe the microbubbles.Subjects and Methods: Laparotomy was performed on 5 pigs. A 16-Fr sheath was inserted into the jugular vein. After inserting a 3.8-mm angioscope into the sheath, a guidewire was used to guide the angioscope to the hepatic vein, and RFA was performed. Microbubbles in the portal vein were also observed by angioscope. A LeVeen TM needle electrode and a cooltip needle electrode were used for RFA.Results: The outflow of microbubbles from the RFA site was observed by angioscope. Conclusions:The results demonstrate that increased intrahepatic pressure causes microbubbles, thus suggesting that some risk of dissemination due to RFA exists.