高强度聚焦超声联合脂质纳米氟碳液滴消融兔肝的实验研究

Experimental study on the ablation of rabbit liver by high intensity focused ultrasound combined with lipid-perfluorocarbon nanodroplets

目的探讨脂质纳米氟碳液滴(L-PFP)增效高强度聚焦超声(HIFU)消融兔肝的空化活动及术后病理学变化。方法采用薄膜水化法制备L-PFP,然后将24只正常新西兰大白兔随机分为对照组(单纯HIFU组)和联合组(L-PFP联合HIFU),每组各12只;于超声引导下行HIFU定点消融兔肝,观察两组强回声区范围和灰度变化值情况;使用被动空化检测系统监控空化活动,观察辐照过程中两组宽带噪声(RMS)和累积瞬态空化剂量情况。分别于辐照前1 d和辐照后即刻、1 d、3 d、7 d检测兔肝功能指标谷丙转氨酶(ALT)和天冬氨酸转氨酶(AST);对辐照后各时间点兔肝标本行HE染色,观察消融灶转归过程中的病理学变化。结果成功制备L-PFP,粒径(278.33±26.06)nm,稳定性良好。HUFI辐照后联合组强回声区范围大于对照组,对照组和联合组灰度变化值分别为45.60±4.07和88.00±7.21,差异有统计学意义(P<0.05)。空化检测结果显示,HIFU辐照过程中两组RMS均总体增强,且随时间波动,联合组RMS高于对照组(P<0.05);联合组累积瞬态空化剂量0.69±0.07,显著高于对照组0.11±0.01,差异有统计学意义(P<0.05)。肝功能检测结果显示,对照组与联合组辐照后即刻、1 d、3 d、7 d ALT和AST均呈先增高后降低的趋势;联合组辐照后1 d、3 d、7 d ALT和AST均高于对照组,差异均有统计学意义(均P<0.05)。大体标本及病理结果显示,联合组组织损伤更严重,细胞变性更彻底,炎性反应更强烈;其中对照组辐照后7 d消融灶恢复为正常组织,联合组辐照后7 d消融区域边缘可见较多正常肝细胞,并伴有条带状纤维化及少量炎性细胞浸润。结论L-PFP可通过增强空化效应有效提高HIFU消融效果,延长消融灶恢复所需时间。

Objective To explore the cavitation activity and postoperative pathological changes of rabbit liver by lipid-perfluorocarbon nanodroplets(L-PFP)synergistic high intensity focused ultrasound(HIFU)ablation.Method L-PFP was prepared by thin-film hydration.Then 24 normal New Zealand rabbits were randomly divided into control group(only HIFU group,n=12)and combined group(L-PFP combined with HIFU,n=12).HIFU was used to ablate rabbit liver under the guidance of ultrasound,the strong echo region and grey scale variation values in both groups were observed.The cavitation activity was monitored by passive cavitation detection system(PCD),the root mean square(RMS)and inertial cavitation dose during irradiation were obserred.Rabbits’liver function indexes(ALT and AST)were detected at 1 d before and immediately,1 d,3 d,7 d after ablation.The rabbit liver specimens were taken out for HE staining,the pathological changes during the ablation process was observed.Results The L-PFP with diameter of(278.33±26.06)nm and good stability were successfully prepared.The strong echo region of combined group was greater than that of control group after HIFU irradiation,the grey scale variation values of control and combined groups were 45.60±4.07 and 88.00±7.21,respectively,there was statistically significant difference(P<0.05).The cavitation detection results showed that RMS was generally enhanced in both groups during HIFU irradiation and fluctuated with time,and RMS of combined group was higher than that of control group(P<0.05),the inertial cavitation dose of control and combined groups were 0.11±0.01 and 0.69±0.07,respectively,there was statistically significant difference(P<0.05).The results of liver function tests showed that ALT and AST were increased and then decreased in both groups immediately after irradiation and at 1 d,3 d,7 d.ALT and AST of combined group were higher than those of control group at 1 d,3 d,7 d after irradiation,and the differences were statistically significant(all P<0.05).Gross specimens and pathological findings showed more severe tissue loss,more complete cellular degeneration and more intense inflammatory response in the combined group.The ablated regions were repaired to normal tissue 7 d after irradiation in the control group,while in the combined group,more normal hepatocytes were seen at the edges of the ablated regions 7 d after irradiation,with striated fibrosis and a small amount of inflammatory cell infiltration.Conclusion L-PFP can effectively improve the ablation effect of HIFU by enhancing the cavitation effect,and prolong the time required for the outcome of the ablation lesion.