超声引导不可逆电穿孔消融山羊肝脏的实验研究

Experimental study on ablating goat liver tissue with ultrasound imaging guided percutaneous irreversible electroporation

目的探讨超声引导经皮穿刺不可逆性电穿孔(IRE)微创消融山羊肝脏组织的可行性、B超影像学特点及其病理学变化。方法 4～6月龄山羊4只,体重25～30kg,采用固定脉宽100μs、频率1Hz、电压2000V的脉冲电场,120个脉冲,经彩色超声探头引导电极针经皮定位穿刺处理肝脏组织,观察处理过程中及处理后即刻2、4h靶区B超灰度变化和肝脏坏死轮廓,并与仿真电场相比较,同时在对应时间点各取材2只行HE组织病理切片观察。结果超声引导经皮IRE消融靶区组织定位准确,与周围正常组织回声明显不同,坏死组织轮廓与电极的电场仿真图像相吻合;光镜观察处理区肝细胞完全坏死,与周围正常细胞分界清楚。结论超声实时引导定位IRE消融范围精确、可控,并可监测处理后坏死区回声变化范围,为IRE的临床应用提供了大动物实验依据。

Objective To investigate the proper method of percutaneous irreversible electroporation（IRE） to ablate goat liver tissue under ultrasonic guidance,and observe the features of ultrasound imaging and histological changes.Methods The pulse electric fields（PEFs） with permanent duration（100 μs）,frequency（1Hz）,voltage（2000V） and pulses（120 pieces） were applied to the electrodes,and the electrodes were placed into goats’ liver under ultrasound guidance through the animal skin to the target area.The treated area was observed by real-time ultrasound scanning,and the histopathological changes were assessed by hematoxylin and eosin（HE） staining under light microscope at the time of 0h and 24h after IRE ablation.The circumscribed ablated area was compared with that of finite element modeling（FEM） calculation method.Results Ultrasound imaging guidance was accurate in focusing on the target area.Imaging captured by the ultrasound after IRE procedure was quite different from that of the normal liver imaging.Complete hepatic cell death with a sharp demarcation between the ablated zone and the non-ablated zone was well visualized 24 hours after the procedure.Necrospy-based measurement demonstrated a high consistence with FEM-anticipated ablation zones.Conclusion With real-time monitoring by ultrasonography and well-controlled ablation of the target tissue,percutaneous IRE can provide a novel and unique ablative method for cancer treatment.The present paper provides a fundamental experimental work for future studies on clinical application of IRE.