Observation of spotty high echoic areas in radiofrequency ablation and ethanol injection therapy

Abstract

Background: During radiofrequency ablation (RFA) and percutaneous ethanol injection (PEI), high echoic areas can be observed by ultrasound. No studies have definitively identified them. Therefore, we used an angioscope to observe the high echoic areas.
Subjects and Methods: Laparotomy was performed on 7 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 and PEI was performed.
Results: The outflow of bubbles was observed by angioscope in RFA. On the other hand bubbles were not observed in PEI.
Conclusions: High echoic areas in RFA are thought to represent steam generated by rapidly heated tissue. On the other hand, the mechanism of high echoic areas in PEI is due to the echo contrast between blood and ethanol.