MR弹性成像与钆塞酸二钠增强T1 mapping定量评估兔肝纤维化的对比研究

Quantitative evaluation of liver fibrosis by MRE and Gd-EOB-DTPA-enhanced T1 mapping magnetic resonance imaging in a rabbit model

目的评价MR弹性成像(magnetic resonance elastography,MRE)、钆塞酸二钠(gadolinium ethoxybenzyl diethyle netriamine pentaacetic acid,Gd-EOB-DTPA)增强T1 mapping在肝纤维化(liver fibrosis,LF)早期定量的价值。材料与方法实验材料为新西兰大白兔(共120只),分为正常对照组(n=20)与肝纤维化组[LF组,50%四氯化碳(carbon tetrachloride,CCL_(4))油溶液模型,n=100],分别在第4、5、6、15周末取5只对照组与25只LF组兔行MRI肝脏轴位T1WI、MRE及Gd-EOB-DTPA增强T1 mapping扫描,测量肝脏弹性硬度(liver stiffness,LS)、平扫T1弛豫时间(T1_(native))及Gd-EOB-DTPA增强T1 mapping扫描20 min后T1弛豫时间(T1_(20min)),计算T1弛豫时间减少率(ΔT1_(20min))及1/T1弛豫时间增加值(ΔR1_(20min));采用Scheuer评分系统进行LF病理学分期,单因素方差分析对比各定量参数与LF分期间的差异,Spearman相关性分析比较各定量参数与LF病理分期相关性,受试者工作特征(receiver operating characteristic,ROC)曲线评估各定量参数对LF分期诊断效能。结果共纳入96只活兔模型,病理学评分:F0期15只、F1期22只、F2期22只、F3期18只、F4期19只。LS、T1_(native)、T1_(20min)、ΔT1_(20min)、ΔR1_(20min)于LF各期间差异均有统计学意义(P<0.05)。LS、T1_(native)、T1_(20min)、ΔT1_(20min)、ΔR1_(20min)均与LF分期相关(r=0.935、0.559、0.770、-0.418、-0.686,P<0.001)。F0 vs.F1~F4、F0 vs.F1~F2、F0 vs.F3~F4、F1~F2 vs.F3~F4的LS值ROC曲线下面积(area under the curve,AUC)分别为0.988、0.979、1.000、0.995,T1_(20min)值AUC分别为0.914、0.852、0.987、0.896。结论在评估LF早期诊断中,MRE及Gd-EOB-DTPA增强T1 mapping成像均显示出较好的诊断价值,MRE优于Gd-EOB-DTPA增强T1 mapping。

Objective:To compare the accuracy of MR elastography(MRE)and Gd-EOB-DTPA-enhanced T1 mapping in the quantitative evaluation of liver fibrosis(LF)staging.Materials and Methods:One hundred and twenty rabbits were randomly divided into control group(n=20),which were injected subcutaneously with normal saline solution,and LF group(n=100),which were received 50%(carbon tetrachloride)CCl_(4) oil solution.The control group(n=5)and LF group(n=25)underwent MRI axial scan,T1WI,MRE,Gd-EOB-DTPA-enhanced T1 mapping at the end of the 4th,5th,6th,15th week.The pathological LF staging was based on Scheuer staging system.The quantitative parameter included liver stiffness(LS),pre-and post-contrast T1 values of the liver(T1_(native) and T1_(20min)),the reduction rate of T1 relaxation time(ΔT1_(20min))and the increase in T1 relaxation rate(ΔR1_(20min)),were compared the differences by one-way ANOVA analysis.Spearman correlation coefficients,Receiver operating characteristic(ROC)analysis was used respectively to determine the correlation and diagnostic performance between quantitative parameters and pathological LF staging.Results:A total of 96 rabbits were included in F0(n=15),F1(n=22),F2(n=22),F3(n=18)and F4(n=19).LS,T1_(native),T1_(20min),ΔT1_(20min),ΔR1_(20min) showed significant differences among all LF staging(P<0.05).There were correlation between LS,T1_(native),T1_(20min),ΔT1_(20min),ΔR1_(20min) and LF stage(r=0.935,0.559,0.770,-0.418-0.686,P<0.001),respectively.LS exhibited the largest area under the curve(AUC),which were 0.988,0.979,1.000,0.995 for F0 vs.F1~F4,F0 vs.F1~F2,F0 vs.F3~F4,F1~F2 vs.F3~F4,respectively.Secondly,the AUC of T1_(20min) were 0.914,0.852,0.987,and 0.896,respectively.Conclusions:In the early quantitative evaluation of LF staging,MRE and Gd-EOB-DTPA enhanced T1 mapping had demonstrated significant diagnostic value,with MRE outperforming Gd-EOB-DTPA enhanced T1 mapping.