Evaluation Of Significant Liver Fibrosis By Ultrasonic Shear Wave Elastography In Rats With Carbon Tetrachloride-induced Liver Injury

Objective:The aim of this study were to explore the evaluation of significant liver fibrosis（SLF）by ultrasonic shear wave elastography（SWE）in rats with carbon tetrachloride（CCl4）-induced liver injury,and to analyze the correlation between liver elastic hardness and pathological degeneration.Method:52 male SD rats were adaptively reared for 1 week,then randomly divided into control group（n=12）and experimental group（n=40）.The liver injury model was induced by intraperitoneal injection of carbon tetrachloride for 4,6,8 and 10 weeks,with 10 rats sacrificed at each time.At end of each experiment,the rats were anesthetized for liver stiffness measurement（LSMs）by SWE.The blood routine and serum biochemical parameters were obtained for calculation of APRI and FIB-4.The LSM immediately after dead（LSMd）was performed again after execution.The liver fibrosis,steatosis and inflammatory activity were evaluated by pathological examination.The receiver operating characteristic（ROC）curve was applied to evaluate the performance of parameters in the diagnosis of SLF.Spearman correlation analysis was used to detect the correlation between LSM and steatosis and inflammatory activity.Result:The pathological examination showed that there were 12 rats with F0 stage,6rats with F1 stage,9 rats with F2 stage,11 rats with F3 stage,and 10 rats with F4 stage for liver fibrosis in SD rats.The F0 stage and F1 stage were defined as non-significant hepatic fibrosis group（n=18）,and F2 stage to F4 stage were defined as significant liver fibrosis group（n=30）.The AST in non-significant hepatic fibrosis group was[83.3（58.8,132.1）U/L],significantly lower than that in significant group[169.6（123.3,421.7）U/L,P<0.05];the APRI score in rats with NSLF was（0.05±0.02）,significantly lower than[（0.14±0.117）,P<0.05],and the FIB-4 score was(0.13^-100±0.09^-100),significantly lower than[(0.25^-100±0.13^-100),P<0.05],the LSMs was（5.2±1.7）k Pa,significantly lower than[（9.7±2.8）k Pa,P<0.05]and the LSMd was（3.6±0.8）k Pa,significantly lower than[（8.8±1.7）k Pa,P<0.05]in rats with SLF;the areas under the ROC curve（AUC）by LSMs and LSMd in predicting SLF were 0.91and 0.93,significantly higher than 0.75 by APRI or 0.69 by FIB-4,with the sensitivities and specificities of 76.7%and 87.5%,and 85.7%and 92.0%,respectively.The liver hardness is not related to steatosis and inflammation（r=0.16,0.27,P<0.05）.Conclusion:The SWE technique has a high clinical value in evaluating LF in rats with CCl4-induced liver injury,with the advantages of non-invasive,simple and repeatable feature.The LSM has no significant correlation with the degree of steatosis and inflammation.