摘要：
Objective To evaluate the value of acoustic radiation force impulse (ARFI) elastography in assessment of nonalcoholic fatty liver disease (NAFLD) and hepatic fibrosis in rats.Methods Models with various degrees of NAFLD severity were conducted in 110 rats by feeding high fat emulsion.The right liver lobe of rat models were processed and embedded in a fabricated gelatin solution to measure the shear wave velocity (SWV) by ARFI.And the other liver lobes were used for histologic assessment.Based on NAFLD activity score (NAS),the final pathologic NAFLD diagnosis were considered as normal group (NAS=0),simple steatosis (SS) group (1≤NAS≤2),borderline (3≤NAS≤4) group and nonalcoholic steatohepatitis (NASH) group (NAS≥5).The diagnostic accuracy of the SWV parameters in evaluating NAFLD severity and fibrosis stages was studied using ROC curves.Results The difference of SWV values among normal group,SS group,borderline group and NASH group was statistically significant (F=31.53,P＜0.001).Taking SWV≥ 2.54 m/s as the diagnostic standard to differentiate normal rats from rats with SS,and SWV≥2.90 m/s to differentiate SS from NASH in rats,the area under ROC curve (AUC) was 0.922 (95％CI [0.871,0.973],P＜0.001) and 0.882 (95％ CI [0.807,0.956],P＜0.001) respectively.The sensitivity and specificity were 93.5 ％ and 100 ％ for differentiating normal and SS groups,83.3 ％ and 84.2 ％ for differentiating SS and NASH groups.Taking SWV≥3.48 m/s as cutoff to predict fibrosis (≥F2 stage),the AUC was 0.963 (95％CI [0.909,1.000],P＜0.001),the sensitivity was 92.9％ and the specificity was 97.6％.Taking SWV≥3.61 m/s as cutoff to predict severe fibrosis (≥F3 stage),the AUC was 0.997 (95％CI [0.990,1.000],P＜0.001),sensitivity was 100％ and specificity was 98.9％.The same high validity was maintained as in the prediction of cirrhosis (F4 stage) with the cutoff as SWV≥4.50 m/s,and the AUC was 0.993 (95％CI [0.982,1.000],P＜0.001),the sensitivity was 100 ％ and the specificity was 96.8％.Conclusion ARFI elastography is a promising method for differentiating the different severity of NAFLD and staging the degree of hepatic fibrosis with NAFLD in rat models.%目的 探讨利用声辐射力脉冲成像(ARFI)技术评估大鼠肝脏非酒精性脂肪肝(NAFLD)及肝纤维化的价值.方法 通过喂养高脂食物建立不同阶段NAFLD大鼠模型.解剖大鼠,取右叶肝脏嵌入明胶仿体内用于ARFI检查,测量大鼠肝脏剪切波速度(SWV),将其余肝组织用于组织学评估,并根据NAFLD活动性评分(NAS),将大鼠分为正常组(NAS=0),单纯性脂肪肝(SS)组(1≤NAS≤2),边界组(3≤NAS≤4)、非酒精性脂肪性肝炎(NASH)组(NAS≥5).通过ROC曲线分析评估ARFI判断不同程度NAFLD及肝纤维化的能力.结果 正常组、SS组、边界组、NASH组间SWV值总体差异有统计学意义(F=31.53,P＜0.001).以SWV值≥2.54 m/s鉴别正常组与SS组、以SWV值≥2.90 m/s鉴别SS组与NASH组,对应的ROC曲线下面积(AUC)分别为0.922[95％ CI(0.871,0.973),P＜0.001]、0.882[95％ CI(0.807,0.956),P＜0.001],敏感度分别为93.5％、83.3％,特异度分别为100％、84.2％.以SWV值≥3.48 m/s诊断≥F2期肝纤维化、以SWV值≥3.61 m/s诊断≥F3期肝纤维化、以SWV值≥4.50 m/s诊断肝硬化(F4期)的AUC分别为0.963[95％CI(0.909,1.000),P＜0.001]、0.997[95％CI(0.990,1.000),P＜0.001]、0.993[95％CI(0.982,1.000),P＜0.001],敏感度分别为92.9％、100％、100％,特异度分别为97.6％、98.9％、96.8％.结论 ARFI技术测量的SWV值可有效评估NAFLD及含有NAFLD的肝纤维化程度.
