Comparison of microwave thermosphere ablation and conventional microwave ablation in ex vivo bovine livers / 中华超声影像学杂志

ABSTRACT

Objective To compare the effectiveness of microwave thermosphere ablation( M T A ) and traditional microwave ablation( M WA ) in ex v ivo bovine livers ,and to compare the degree of the heat sink effect in them .Methods T he non‐vessel model and vessel model were established using fresh bovine livers . In non‐vessel model ( n ＝ 48 ) ,the same power‐time settings were used in both M T A group and MWA group ,w hich were 80 W 12 min ,90 W 10 min and 100 W 10 min ,respectively . Long‐axis diameter ( Dl) , short‐axis diameter( Ds1 ,Ds2) ,roundness index ( R) and the time of temperature rising to 60℃ at place of 10 mm from the needle were measured .In vessel model( n ＝144) ,different vessel diameters( 3 mm ,5 mm ,10 mm) and flow rates ( 15 cm/s ,20 cm/s ,30 cm/s) were setted . The maximum radius( Rmax) ,total area of ablation zone( Sz ) ,and the area difference ( Sdiff ) were analyzed ,the temperatures adjacent to the vessel were monitored simultaneously . Results In non‐vessel model ,with the same power and time settings ,the Dl of M T A group was significantly smaller than MWA group ( P ＜ 0 .01 ) , however , there was no significant difference of Ds1 and Ds2 between the two groups( P ＞0 .05) . And M T A group created more spherical ablation zones ,since the R of M T A group were more close to 1 ( P ＜0 .01) . In M T A group ,the time of temperature rising to 60 ℃ at place of 10 mm from the needle was slower than MWA group ( P ＜0 .01) . In vessel model ,the Sdiff of M T A group were hardly affected by the vessel diameters and flow rates ( P ＞0 .05) ,and there was also no statistical significance among different flow rates( P ＞0 .05 ) in M WA group ,but the Sdiff of M WA group was significantly affected by the vessel diameters( P ＜0 .01) . And the Sdiff of M T A group was significantly smaller than M WA group when the vessel diameter was 10 mm ( P ＜0 .05) ,while there was no statistical significance between the two groups w hen the vessel diameter was 3 mm or 5 mm( P ＞0 .05) . Conclusions Compared to M WA ,M T A can produce sizable ,regular and more spherical ablation lesions with the same power and time ,meanwhile ,it is less affected by the heat sink effect .