钆塞酸二钠增强MRI肝胆期全肝直方图分析评估兔肝纤维化的研究

Study of whole-liver histogram analysis based on Gd-EOB-DTPA hepatobiliary phase for evaluating liver fibrosis in rabbits

目的探究钆塞酸二钠(gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid,Gd-EOB-DTPA)增强MRI肝胆期全肝直方图分析定量评估兔肝纤维化(liver fibrosis,LF)的价值。材料与方法随机将100只新西兰大白兔分为四氯化碳诱导的LF组(80只)和健康对照组(20只),并进行Gd-EOB-DTPA增强MRI肝胆期成像。采用Firevoxel软件勾画肝胆期全肝感兴趣区获取直方图最小值、最大值、平均值、中位数、偏度、峰度、不均质性、熵值和百分位数(n-(th))。以病理结果为对照,通过曼-惠特尼秩和检验(Mann-Whitney U检验)和受试者工作特征曲线(receive operating characteristic curve,ROC)分析不同LF分期的参数值差异。结果共纳入84只实验兔,F0、F1、F2、F3、F4期各有18、17、17、18、14只。直方图参数值不均质性(r=0.809)、90-(th)(r=0.718)、75-(th)(r=0.645)、熵值(r=0.546)、中位数(r=0.425)和峰度(r=0.305)与LF进展呈明显正相关。不均质性、90-(th)、75-(th)、熵值可有效鉴别诊断正常(F0)、早期(F1-F2)及晚期(F3-F4) LF。参数值不均质性鉴别诊断LF的价值最高,诊断F0与F1-F4、F0与F1-F2、F1-F2与F3-F4、F0与F3-F4的AUC值分别为0.87、0.77、0.90、0.97。结论 Gd-EOB-DTPA增强MRI肝胆期全肝直方图分析对诊断LF具有较高的价值。

Objective:To explore parameters derived from whole-liver histogram analysis(HA)with Gd-EOB-DTPA enhanced MRI hepatobiliary phase in quantitatively evaluating liver fibrosis(LF).Materials and Methods:One hundred rabbits were randomly divided into CCl4-induced LF group(n=80)and control group(n=20),and then were scheduled for hepatobiliary phase imaging examination.Whole-liver region of interest was drawn,and histogram analysis metrics including minimum,maximum,mean,median,skewness,kurtosis,inhomogeneity,entropy,and nthpercentiles were extracted from hepatobiliary phase.Parameters were compared among different LF stages using Mann-Whitney U test and receivers operating characteristic curve,using histopathological results as reference standard.Results:Eighty-four patients were enrolled,18,17,17,18,and 14 rabbits were pathologically diagnosed as F0—F4,respectively.HA parameters including the inhomogeneity(r=0.809),90th(r=0.718),75th(r=0.645),entropy(r=0.546),median(r=0.425)and kurtosis(r=0.305)of hepatobiliary phase demonstrated significant positive correlation with increasing fibrosis stage(P<0.05).Inhomogeneity,90th,75th and entropy were of value in different normal(F0),early stage(F1—F2)and advanced(F3—F4)stage.The inhomogeneity parameter demonstrated higher diagnostic efficacy than other histogram analysis parameters in fibrosis staging,with an AUC value of 0.87 for F0 vs.F1—F4,0.77 for F0 vs.F1—F2,0.90 for F1—F2 vs.F3—F4,and 0.97 for F0 vs.F3—F4.Conclusions:Histogram analysis of Gd-EOB-DTPA enhanced MRI hepatobiliary phase provide higher diagnostic value in distinguishing LF stages,which can be served as an effective imaging alternative in staging LF.