Evaluation Of Liver Fibrosis In Rabbits Model By Acoustic Radiation Force Impulse Imaging And S Index

Objective To evaluate ARFI and S index as well as their combinations, in the assessment of liver fibrosis in rabbits.Methods40rabbits were randomly divided into experimental group (32rats) and control group (8rats), the experimental group was induced by the first time subcutaneous injection of5%thioacetamide (TAA) at a dose of1.5ml/kg of body weight and then1.0ml/kg two times a week; the control group by subcutaneous injection of saline at same dose.8-10rabbits in the group with TAA injected and2-3rabbits of normal control group were randomly selected for ARFI elastography and serum biochemical examination to calculate S index at4th,8th and12th weekend after the first injection. Then rabbits were killed and taken the liver for pathological diagnosis. Using receiver operating characteristic (ROC) curve to evaluate ARFI, S index of individual and combined in the diagnosis of liver fibrosis.Results Among29successfully modeled rabbits,10,8,7and4rabbits were found to be with S1, S2, S3and S4of liver fibrosis pathologically, respectively. And3rabbits were found to be with severe liver inflammatory activity without any fibrosis.37rabbits were successfully completed ARFI testing. Diagnosis of liver fibrosis stage S1-S4SWV and S index values were1.32m/s (S index of0.02), the1.62m/s (S index of0.04), the1.96m/s (S index of0.11), the2.04m/s (S index of1.84),respectively.Values of SWV and S index increased with the stage of liver fibrosis (P＜0.05). ARFI (r=0.724, P＜0.001) had a better correlation with liver fibrosis stage than S index (r=0.472, P＜0.001). The areas under the ROC curves for the diagnosis of liver fibrosis, that ARFI and S index were0.868and0.753for S≥2,0.822and0.706for S≥3,0.886and0.735for S=4, respectively. The combination of ARFI with S index for S≥S3areas under the ROC curve was0.864.It was greater than single ARFI or S index tests.Conclusion1.Subcutaneous injected TAA can successfully make liver fibrosis model in rabbits.2.Noninvasive diagnosis of ARFI and S index can be used for liver fibrosis. ARFI is more accurate when applied to evaluate liver fibrosis in rabbits than S index. The combination of ARFI with S index improve the accuracy of the diagnosis of significant liver fibrosis.