Experimental study on microwave ablation of liver tissue in vitro

Objective To investigate the abaltion zone of liver tissue by microwave ablation in vitro. Methods The mirowave ablation to liver tissue were monitored by ultrasound. The experiments by single electrode needle were performed with different combination of output power and time. After end of trial,the longitudinal specimens were cut open. The view and size of ablation zone were recorded with naked eyes. The pathological changes displayed by optical microsope were recorded as well. Results Under the same initial output power the ablation lesions expanded with time( P 0. 05) ; the ablation lesions in 70 W-power was bigger than that in 50 W-power with the same time( P 0. 05) . Ultrasonic measurement of the ablation zone was bigger than the real one( P 0. 05) . Under optical microsope,the center of ablation zone liver tissue manifested topical coagulative necrosis. With the distance 0. 5 cm from solidification zone edge only one specimen remained liver cells,and there were 17 cases at the distance of 1 cm. Conclusions Microwave ablation zones in the liver tissue are significantly expanded with increase of energy power and prolongation of ablation time. The size is bigger in ultrasound scanning than that of the pathomorphology. There is transitional zone between the ablative lesion and the adjacent tissue.