Experimental study of polymeric microcapsules with liquid perfluorocarbon enhancing high intensity focused ultrasound ablation of normal liver

Abstract

Objective To study the optimal power of self-made polymeric microcapsules with liquid perfluorocarbon enhancing high intensity focused ultrasound (HIFU) ablation of normal bovine in vitro and the treatment efficacy of HIFU ablation of normal rabbit liver in vivo.Methods The experiment was divided into two parts:the first part was HIFU ablation of bovine in vitro:The bovine was injected different drugs before HIFU ablation to find the optimal power and treatment time.It was divided into four groups:①HIFU + 0.9％ NaCl(NACL) group; (② HIFU + poly( lactic-co-glycolic acid) (PLGA) group; ③ HIFU + perfluorohexane(PFH) group; ④ HIFU + PLGA + PFH group; The second part was HIFU ablation of normal rabbit liver.Similarly,It was also divided into four groups as above.Each group was undergone HIFU ablation with same parameters after ear vein injection of drug.Then the ultrasonographic changes and its value,and the actual situation of liver damage in target areas of each group were observed and compared before and after the ablation area.Results In experiments of vitro bovine,gray scale changes and coagulation necrosis could be seen in the liver in group 2,3,4 with HIFU power of 150 W and treatment time of 2 s.In experiment of normal rabbit liver,the average gray-scale of group 3 and 4 were larger than that in group 1 and 2,the difference was statistically significant (P ＜0.001),and its gray change area gradually reduced with time elapsed.While there was no statistically significant difference between group 3 and 4 ( P ＞0.05).In pathological specimens,there was no significant liver damage in group 1 and 2.There was hemorrhagic necrosis and white coagulation necrosis in group 3 and 4.Conclusions The polymeric microcapsules with liquid perfluorocarbon can effectively enhance the efficacy of HIFU ablation and be used as a good synergist for HIFU. Key words: Ultrasound,high-intensity focused; Liver