声脉冲辐射力成像评价大鼠肝纤维化的实验研究

Evaluation of liver fibrosis in a rat model by acoustic radiation force impulse elastography

目的 探讨声脉冲辐射力成像技术无创评价大鼠肝纤维化的价值.方法 应用二甲基亚硝胺对70只Wistar大鼠以50mg/kg的剂量一次性腹膜腔注射,复制大鼠肝纤维化模型作为实验组,10只Wistar大鼠腹膜腔一次性注射同等量生理盐水作为对照组.造模后于第5、7、10、14、21和28 d分别随机从实验组中取9～10只、对照组中取1～2只大鼠进行声脉冲辐射力成像检查,记录反映肝剪切波速度的声触诊组织量化值（shear wave velocity,Vs）.随后处死大鼠,取其肝行病理分析.分析声触诊组织量化值与病理之间的关系.结果 58只大鼠造模成功,肝纤维化分级S1、S2、S3和S4者分别有9、13、14和12只,10只大鼠肝严重炎症坏死而无纤维化.声触诊组织量化值随着纤维化程度的增加而增大,各组间差异均具有统计学意义（P＜0.05）；Vs与肝纤维化病理分级间具有显著相关性（r =0.947,P=0.000）;应用Vs诊断S≥S1、S≥S2、S≥S3和S=S4对应的ROC曲线下面积分别为0.983、0.995、0.999和0.964,对应的Vs临界值分别为1.59 m/s、2.13 m/s、2.33 m/s和2.51 m/s,敏感性分别为95.8％、92.3％、100％和84.6％,特异性分别为100％、100％、96.9％和95.6％.10只无纤维化但有严重炎症坏死的大鼠的Vs明显较无纤维化且无炎症坏死大鼠高（P=0.000）.结论 声脉冲辐射力成像技术评价大鼠肝纤维化具有较高的价值,但严重的炎症坏死会影响其准确性.

Objective To investigate the usefulness of acoustic radiation force impulse （ARFI） elastography for noninvasive evaluation of liver fibrosis in rats.Methods A total of 70 male Wistar rats were included in the group for dimethylnitrosamine （DMN）-induced liver injury,and 10 saline-injected rats were used as normal control.Hepatic injury was induced by a single intraperitoneal injection of DMN at a dose of 50 mg/kg of body weight.Several rats in the group with DNM injected and the normal control group were randomly selected and sacrificed at each of the following post-injection time：day 5,7,10,14,21,24,and 28.And their livers were taken for pathology analysis.All the rats underwent ARFI elastography before sacrificed in order to acquire a shear wave velocity （Vs） to represent liver stiffness.Correlation between Vs and the histological finding was analysed.Results Among 58 successfully modeled rats,9,13,14 and 12 rats were found to be with S1,S2,S3 and S4 of liver fibrosis pathologically,respectively.And 10 rats were found to be with severe inflammatory activity without any fibrosis.Values of Vs increased with the stage of liver fibrosis （ P 〈0.05）.There was a significant correlation between Vs and stage of liver fibrosis （ r =0.947,P =0.000）.The areas under ROC curve for the diagnosis of fibrosis S≥S1,S≥S2,S≥S3 and S=S4 were 0.983,0.995,0.999 and 0.964,respectively;for the cutoff values of Vs were 1.59 m/s,2.13 m/s,2.33 m/s and 2.51 m/s,respectively,the sensitivity was 95.8%,92.3%,100% and 84.6%,and specificity was 100%,100%,96.9% and 95.6%,respectively.The values of Vs in the group with severe inflammatory activity were significantly higher than those in the control group （ P =0.000）.Conclusions ARFI has a relatively high value in the evaluation of liver fibrfosis in rats,while severe inflammatory activity may affect its accuracy.