成年犬前列腺微波消融效果的实验研究

Microwave ablation of the canine prostate:An experimental study

目的:探讨超声引导下微波消融对犬前列腺组织的效果。方法:将12只犬按照时间-功率组合随机分为2组,每组6只,A组:40 W/120 s;B组:40 W/160 s。犬麻醉后在超声引导下经直肠穿刺前列腺左右两侧叶部分别进行微波消融,消融过程中常规灰阶超声实时观察消融灶的变化,消融完成后进行超声造影并测量消融灶体积,最后处死动物取出前列腺标本,沿电极长轴剖开前列腺观察消融灶的形态并实测消融灶的体积。结果:①消融开始后常规灰阶超声显示电极裂隙处首先出现强回声,后方伴有明显声尾,随消融时间增加强回声范围逐渐扩大,最后消融区表现为不均匀强回声,边界清晰,形态欠规则。②超声造影显示凝固性坏死区表现为类椭圆形的造影剂缺损区(无回声),与周围增强的前列腺组织形成鲜明对比,边界更加清晰。造影模式下测量的A组和B组消融灶体积分别为:(1.18±0.23)cm3和(1.52±0.23)cm3。③大体标本观察消融灶呈椭圆形,整个消融灶颜色苍白,与周围前列腺组织边界清楚。标本实测的消融灶体积分别为:A组:(1.13±0.20)cm3;B组:(1.48±0.20)cm3。结论:不同时间-功率组合可以在前列腺内形成不同大小的凝固性坏死灶,超声造影可以准确反映凝固性坏死范围,避免消融治疗的过度和不足。

Objective： To investigate the effect of transrectal ultrasound-guided microwave ablation of canine prostate tissue. Methods： Guided by transrectal ultrasound, we conducted microwave ablation on each side of the prostate in 12 male dogs, 6 at 40 W/ 120 s （group A） and the other 6 at 40 W/160 s （group B）, and observed the changes in the thermal lesions using grayscale ultrasound. After thermal ablation, we measured the volume of the thermal lesions by contrast-enhanced ultrasound （CEUS）. Then we harvested the whole prostate from the animals and determined the lesion volumes in the fresh tissue specimens. Results： Grayscale uhra- sound revealed an echogenic area at the initiation of the microwave ablation procedure, which was enlarged with the increase of ablation time. At the end of the procedure, the lesions appeared as an irregular heterogeneous echogenic area. CEUS showed oval non-perfused areas, which appeared as well-defined non-echoic areas in sharp contrast with the surrounding normal prostate parenchyma with bolus injection of contrast material （ Sonovue, 2.4 ml）, and that the thermal lesion volumes of groups A and B were （ 1.18 ± 0.23 ） cm3 and （ 1.52 ±0.23） cm3 , respectively. The thermal lesions of the gross specimen exhibited an elliptical shape, pale color and clear margin, and their volumes were （1.13±0.20） cm3 and （1. 48 ±0.20） cm3, respectively, in groups A and B. Conclusion： Different combinations of time and power can produce coagulative necrotic lesions of different volumes in the local prostatic tissue. CEUS can accurately manifest the lesion area and thus avoid excessive or inadequate ablation treatment.