MR弹性成像与钆塞酸二钠动态增强MRI定量评估肝纤维化的实验研究

An experimental study of MR elastography and Gd-EOB-DTPA dynamic contrast-enhanced MRI in quantitative evaluation of liver fibrosis

目的对比MR弹性成像(MRE)、钆塞酸二钠(Gd-EOB-DTPA)动态增强MRI(DCE-MRI)在定量评估实验兔早期肝纤维化(LF)分期的诊断效能。方法2019年4月至12月间,选取200只健康、纯种新西兰大白兔,随机区组分组法分为LF组(n=160)和对照组(n=40)。对LF组采用皮下注射50%CCL_(4)油溶液构建LF模型,对照组注射等量生理盐溶液,第4、5、6、16周末随机选取40只LF组和10只对照组实验兔进行MRI扫描,包括MRE和DCE-MRI扫描,获得定量参数肝脏弹性硬度值(LS)、容积转运常数(K^(trans))、反流速率常数(K_(ep))、血管外细胞外间隙容积分数(V_(e))、血浆容积分数(V_(p))。扫描后处死动物进行肝脏组织病理学检查,依据Scheuer分期标准进行LF分期。采用单因素方差分析比较不同LF分期间各定量参数的差异,以Spearman相关评价各定量参数与LF分期的相关性,使用ROC曲线评估各定量参数对LF分期的诊断价值。结果本研究共纳入150只兔,F0期32只、F1期32只、F2期35只、F3期30只、F4期21只。不同LF分期间LS、K_(ep)、V_(p)、K^(trans)、V_(e)的总体差异均有统计学意义(P均<0.05)。LS、K^(trans)与LF分期呈正相关(r=0.832、0.730,P<0.001);K_(ep)与LF分期呈负相关(r=-0.617,P<0.001);V_(e)、V_(p)与LF分期间无明显相关性(r=-0.074、P=0.367,r=-0.078、P=0.342)。ROC曲线显示LS诊断效能较高,诊断LF(F0与F1~F4)、诊断早期LF(F0与F1~F2)、诊断进展期LF(F0与F3~F4)、鉴别早期与进展期LF(F1~F2与F3~F4)的AUC分别为0.920、0.900、0.945、0.926;K^(trans)的相应AUC分别为0.897、0.863、0.942、0.809。结论MRE与Gd-EOB-DTPA DCE-MRI对兔LF分期具有诊断价值,MRE定量指标LS诊断效能优于DCE-MRI指标。

Objective To compare the diagnostic efficacy of MR elastography(MRE),Gd-EOB-DTPA dynamic contrast-enhanced MRI(DCE-MRI)in early quantitative evaluation of liver fibrosis(LF)staging of experimental rabbits.Methods From April to December 2019,200 healthy rabbits were randomly divided into LF group(n=160)and control group(n=40).LF group were injected subcutaneously with 50%CCl_(4) oil solution,while control group were injected with normal saline solution.The LF group(n=40)and control group(n=10)were randomly selected at the end of the 4th,8th,12th and 16th weeks respectively to undergo axial MRI scan including MRE and Gd-EOB-DTPA DCE-MRI.The quantitative parameter values were obtained,including liver stiffness(LS),volume transfer constant(K^(trans)),reflux rate constant(K_(ep)),volume fraction of extravascular extracellular space(V_(e))and volume fraction of plasma(V_(p)).Histopathological LF staging was based on Scheuer staging.One-way ANOVA analysis was used to evaluate the differences of LS,K^(trans),K_(ep),V_(e) and V_(p) among different LF stages.The Spearman correlation analysis was used to evaluate the correlations between pathological LF staging and quantitative parameter values.The ROC curve was used to compare the diagnositic performance of all quantitative parameter values.Results Among the final qualified 150 rabbits,there were 32 in F0,32 in F1,35 in F2,30 in F3,21 in F4.Significant differences of LS,K^(trans),K_(ep),V_(e) and V_(p) were found among different LF stages.There was correlation between LS,K^(trans),K_(ep) and LF stages(r=0.832,0.730,-0.617,all P<0.001),respectively.However,no statistically correlation was found between V_(e),V_(p) and LF stages(r=-0.074,P=0.367;r=-0.078,P=0.342).The area under the ROC curve(AUCs)of LS were the greatest(0.920 for F0 vs F1-F4,0.900 for F0 vs F1-F2,0.945 for F0 vs F3-F4,0.926 for F1-F2 vs F3-F4),while the AUCs of K^(trans) were 0.897,0.863,0.942,0.809,respectively.Conclusion The early quantitative diagnostic efficacy for LF staging by MRE was superior to Gd-EOB-DTPA DCE-MRI in rabbits.