Extended Tofts双室模型在肝硬化DCE-MRI定量分析中的研究

The study on extended tofts two-compartment model of quantitative dynamic contrast-enhanced MRI in liver cirrhosis

目的:探讨Extended Tofts双室模型在肝硬化动态对比增强磁共振(DCE-MRI)定量研究中的应用价值。方法:对符合入组标准和排除标准的20例肝硬化代偿期患者、15例失代偿期患者和15例正常对照者行肝脏DCE-MRI扫描,由2名高年资MRI诊断医师分别使用Extended Tofts模型计算各组的定量参数,包括对比剂容积转运常数(Ktrans)、速率常数(Kep)、血管外细胞外间隙容积分数(Ve)、血管(血浆)间隙容积分数(Vp)、肝动脉灌注指数(HPI)、血容量(BV)、血流量(BF)、对比剂平均通过时间(MTT)。2名医师所测数值分别记录为测量1和测量2两组。代偿期肝硬化组、失代偿期肝硬化组和正常对照组间定量参数的比较采用单因素方差分析,两两间的比较采用LSD检验。筛选出三组间具有统计学差异、且测量1和测量2的组内相关系数(ICC)较高的定量参数。绘制受试者工作特征(ROC)曲线评价Ktrans、Ve、HPI、MTT对肝硬化的诊断效能。应用ICC比较测量1和测量2两组结果的一致性。结果:测量1和测量2两组结果显示,肝硬化组Ktrans和Ve低于正常组,HPI和MTT高于正常组,BF低于正常组,差异均具有统计学意义(P均<0.05),HPI和MTT在三组间两两比较,均具有统计学差异(P均<0.05)。测量1和测量2两组的Ktrans、Ve、HPI、MTT的ICC值分别为0.707、0.673、0.869,0.838。ROC曲线分析显示:Ktrans和Ve对失代偿期肝硬化诊断效能较高(敏感度均为90%,特异度均为80%);HPI和MTT对代偿期和失代偿期肝硬化均有较高的诊断效能(敏感度、特异度均≥75%)。结论:Extended Tofts模型在肝硬化的DCE-MRI定量分析中复测性良好,能够评价肝硬化的严重程度。

Objective： To investigate the value of Extended Torts two-compartment model of quantitative dynamic contrast-enhanced MRI （DCE-MRI） in liver cirrhosis. Methods：20 patients with compensatory liver cirrhosis, 15 patients with decompensatory liver cirrhosis and 15 healthy volunteers were enrolled and underwent liver DCE-MRh Quantitative parameters of three groups were obtained as measure 1 group and measure 2 group by two with Extended Torts model,including：volume trans- fer constant of the contrast agent （Ktrans）,Reverse reflux rate constant （Kep）,Volume fraction of EES （Ve）,Volume fraction of plasma （Vp） and arterial perfusion index （HPI）, blood volume （BV）, blood flow （BF） ,mean transit time （MTT）. The parameters of three groups were compared by ANOVA analysis and LSD test for every two groups. The diagnostic efficacy -or liver cirrhosis of Ktrans, Ve, HPI and MTT was analyzed by ROC. Intraclass correlation coefficient （ICC） was used to evaluate the reproducibility of two groups. Results：The results of measure 1 and 2 group showed：The decrease of Ktrans and Ve was found significant among three groups;the increase of HPI and MTT and de- crease of BF were found significant among three groups, as well as significant in HPI and MTT between every two groups （P-0.05）. The ICC value of Ktrans,Ve, HPI and MTT were 0. 707,0. 673, 0. 869,0. 838. Ktrans and Ve showed high efficiency in diagnosis of decompensatory liver cirrhosis,and HPI and MTT showed high efficiency in diagnosis of both compensatory and decompensatory liver cir- rhosis according to ROC （both Sensitivity and specificity were over 75%）. Conclusion：The reproducibility of quantitative DCE MRI with Extended Torts model was good, and could evaluate severity of liver cirrhosis.