2450MHz水冷循环微波消融离体牛肝脏实验——参数设定对消融灶形态与方位的影响

2450 MHz cooled-shaft microwave ablation of bovine liver in vitro: the effect of experimental parameter settings on the morphology and orientation of ablation lesions

目的探讨微波消融（MWA）时间、输出功率对消融灶形态特点与方位的影响。方法取新鲜离体牛肝脏8副，重5．2～6．5kg，采用国产2450MHz水冷循环MWA系统对离体牛肝脏作消融。根据微波参数，将实验分为不同输出功率（40、60、80、100W）组和不同消融时间（5、10、15、20min）组，每项设定参数下重复作5次消融。消融后沿针道切开肝脏组织，测量消融灶的纵径（LD）、横径（TD）、针尖前冲径（PD），计算消融灶类圆率（SR）。结果消融时间恒定条件下，随着微波输出功率增加，消融灶LD、TD逐渐增大（P均〈0．05），PD、SR并未增大（P均〉0．05）；输出功率恒定条件下，随着消融持续时间延长，消融灶LD、TD、PD逐渐增大（P均〈0．05），SR越接近于1（P〈0．05）。结论增加微波输出功率能有效扩大消融灶LD、TD，但未增大PD、SR；延长消融持续时间既可扩大消融灶LD、TD、PD，还可获得类圆性更好的消融灶。

Objective To investigate the effect of different ablation time and microwave output power on the morphology and orientation of ablation lesions. Methods Eight pieces of fresh isolated bovine livers, weighting 5.2-6.5 kg, were collected. By using domestic 2 450 MHz cooled-shaft microwave ablation system, microwave ablation of the isolated bovine livers was carried out. According to the parameters setting used （output power and ablation time）, the experiments were divided into 40 W, 60 W, 80 W and 100 W groups and 5 rain, 10 rain 15 min and 20 rain groups. Under the condition of each setting parameter, microwave ablation procedure was repeated for five times. After microwave ablation, the liver tissue was cut open along the needle path. The longitudinal diameter （LD）, transverse diameter （TD） and preshoot diameter （PD） of the ablation foci were measured, and the sphericity ratio （SR） of ablation focus was calculated. Results Under the condition of a given constant ablation time, with the increasing of microwave output power both LD and TD of ablation foci became gradually increased （P〈0.05）, while PD and SR were not increased （P〉0.05）. Under the condition of a given constant output power, with the increasing of ablation time the LD, TD and PD of ablation foci became gradually increased （P〈0.05）, and SR was gradually close to one （P〈0.05）. Conclusion The increasing of microwave output power can effectively expand the LD and TD of ablation foci, although the PD and SR are not enlarged. The increasing of microwave ablation time can remarkably enlarge the LD, TD and PD of ablation loci and ablation foci in more spherical shape can be obtained.（J Intervent Radiol, 2016, 25： 52-55）