The Experiment Of The Degree Of Liver Fibrosis Measured By Real-time Tissues Elastography In Rats With Immune Hepatitis

Objective:1. To investigate the value of quantitative parameters of elasticity evaluating fibrosis staging in rats with immune hepatitis.2. To investigate the effect of inflammation on fibrosis staging measured with quantitative parameters of elasticity in rats with immune hepatitis. Methods:A total of 60 Sprague Dawley male rats were enrolled in this study and they were randomly divided into a model group and a control group. 52 rats were injected with swine serum through tail vein as model group, while 8 rats were injected with saline as control group. Rats were randomly subjected to real-time tissue elastography(RTE) biweekly. All the rats were performed with tissue dispersion quantitative analysis to obtain 12 quantitative parameters of elasticity, including relative mean value(MEAN), standard deviation(SD), blue area%(%AREA), complexity(COMP), kurtosis(KURT), skewness(SKEW), contrast(CONT), entropy(ENT), inverse difference moment(IDM), angular second moment(ASM), correlation(CORR) and liver fibrosis index(LF Index). Subsequently, rats were sacrificed and liver specimens were taken for pathologic examination. According to pathologic examination rats were divided into S0~S4group(Masson stain) and G0~G4group(HE stain). Kruskal-Wallis test was used for comparison among groups. Spearman rank correlation analysis was used for correlation analysis. Receiver operating characteristic(ROC) curves were used to optimize the cutoff values and evaluate diagnostic performance of LF Index. Results:Except COMP, KURT and CORR, the other 9 quantitative parameters of elasticity had statistically differences(P<0.05), and among these 9 quantitative parameters of elasticity LF Index had the strongest correlation with fibrosis staging(r=0.809, P<0.05). Except KURT and CORR, the other 10 quantitative parameters of elasticity had statistically differences(P<0.05), and among these 10 quantitative parameters of elasticity LF Index had the highest correlation with inflammation grading(r=0.766, P<0.05). The cutoff values of fibrosis stages were 2.35 for grade 1 or higher(area under ROC curve [AUC], 0.940; sensitivity, 97.1%; specificity, 73.3%); 2.99 for grade 2 or higher(AUC, 0.865; sensitivity, 78.6%; specificity, 81.0%); 3.48 for grade 3 or higher(AUC, 0.924; sensitivity, 94.4%; specificity, 87.1%); 4.05 for grade 4(AUC, 0.933; sensitivity, 87.5%; specificity, 95.1%). 79.6%(39/49) of rats were correctly evaluated by LF Index, but 20.4%(10/49) of rats had false-positive. Conclusions:RTE could be used to noninvasively evaluate fibrosis staging in rats with immune hepatitis. However, inflammation had effect on the accuracy of this technique.