目的比较不同脉冲高强度聚焦超声(HIFU)辐照方式损伤离体灌注猪肝靶区临近含较大血管时的损伤情况,为临床应用提供依据。方法建立离体猪肝经肝动脉和门静脉的体外循环灌注模型,在B超引导下选择直径为4mm血管,于血管方向离管壁3rnln位置给予相同剂量PHIFU辐照。实验组选择脉冲波,对照组用连续波,辐照结束后观察声通道血管及靶区损伤情况,并取血管与靶区处组织送病理检查。结果PHIFU相同剂量辐照声通道内含4mm大血管后,实验组和对照组的声通道血管均未见损伤,两组凝固性坏死体积比较存在差异(P〈0.05),实验组坏死体积大于对照组。声通道血管进行HE染色、血管弹力纤维和胶原纤维染色显示没有损伤,实验组和对照组没有差别(P〉0.05)。结论当靶区临近含有较大血管时,脉冲辐照能够提高HIFU治疗效率,有效的形成损伤,且不会损伤血管。
Objective To compare the effect of ablations with pulsed and continuous high-intensity focused ultrasound (HIFU) on the target area containing large blood vessels in isolated perfused porcine liver. Methods An isolated perfused liver model was established by perfusing the isolated porcine liver with autologous blood through the portal vein and hepatic artery using an cardiopulmonary bypass machine. With B-mode ultrasound guidance, a blood vessel about 4 mm in diameter was selected, and pulsed and continuous HIFU ablation at the same dose was delivered along the blood vessel at 3 mm to the vascular wall. After the ablation, the damages of the blood vessels as the acoustic channel and the target area were inspected, and the tissues at the interface of target volume and blood vessels were sampled for pathological examination. Results Neither pulsed nor continuous HIFU caused noticeable injuries of the acoustic channel vessels, but the volume of necrotic tissues in the target area differed significantly between the two groups (P〈0.05). HE staining and vessel staining did not show any injuries of the blood vessels in the pathway of ultrasound ablation in neither of the groups (P〉0.05). Conclusions When the target area contains large blood vessels in the pathway of ultrasound ablation, pulsed HIFU can have better therapeutic efficiency to effectively induce tissue damages without affecting the blood vessels.