活体和离体猪肝模型中微波消融尖端功率与凝固区大小的关系

Correlation between the zone size of coagulation and the tip-power of microwave ablation in ex vivo and in vivo porcine liver models

目的探讨活体和离体猪肝模型2 450 MHz微波消融尖端功率与凝固区大小的关系。方法微波消融研究包括30个离体猪肝和25个活体猪肝消融位点。尖端功率分别设置为40、60和80 W,消融时间设置为6min。球形指数简化为r1^2/r2^2（r1：短轴;r2：长轴）。结果在活体和离体猪肝模型中,微波消融凝固区的大小随尖端功率的提高明显增大。在离体猪肝模型中,尖端功率为80W,凝固区最大短径和长径分别为（25.8±0.8）mm和（49.3±2.2）mm;活体猪肝模型中凝固区最大短径和长径分别为（38.0±3.8）mm和（52.8±9.1）mm。尖端功率提高可以显著减小凝固区球形指数（40 W为0.4±0.2,80 W为0.3±0.0）,差异有统计学意义（P=0.018）。病理提示消融区包括3部分：中心区域的碳化区、围绕碳化区周围的凝固坏死区以及最外层的充血边缘。结论微波消融中尖端功率可以显著影响凝固区的大小。

Objective To investigate the correlation between the zone size of coagulation and microwave tip-power with 2 450 MHz antenna in ex vivo and in vivo porcine liver models. Methods There were 30 in ex vivo and 25 in vivo porcine livers performed by microwave ablation. Three tip-power settings（40, 60 and 80 W） were used during the operation with 6 minute fixed duration. The sphericity index was simplified as r1~2/r2~2（r1, short-axis; r2, long-axis）. Results The zone size of coagulation in microwave ablation significantly increased with the increasement of tip-power in both ex vivo and in vivo models. The maximum zone sizes of coagulation in livers achieved at r1=（25.8 ± 0.8）mm, r2=（49.3 ± 2.2） mm in ex vivo model, and r1=（ 38.0 ± 3.8）mm, r2=（52.8 ± 9.1）mm in vivo model, respectively, when the greatest tip-power was 80 W. The sphericity index of coagulation significantly reduced by the increasement of tip-power[（0.4±0.2） at 40 W and（0.3±0.0） at 80 W, P=0.018]. Pathological examination indicated that all ablation zones consisted of a central area of charring zone surrounding by the zone of coagulation and a rim of hyperemia. Conclusion The zone size of coagulation in microwave ablation is significantly affected by the tip-power.