缺血性脑白质病变DCE-MRI药代动力学模型选择

目的:探讨动态对比增强磁共振成像不同计算模型在缺血性脑白质病中的应用价值.方法:2016年4月-10月共搜集57例受试者,根据Fazekas评分分为两组:0～2分为对照组(共18例,男10例,女8例),3～6分为病例组(共39例,男17例,女22例).所有研究对象进行DCE-MRI检查,通过两种不同的计算模型(Patlak模型、Extended Tofts双室模型)测量研究对象脑白质病变区域的容积转运常数(Ktrans),采用Mann-Whitney U检验比较两组Ktrans值的差异,并应用ROC曲线分析不同计算模型所得Ktrans值的敏感度及特异度.结果:Patlak模型计算所得两组的Ktrans值分别为0.20(0.05,0.31)×10-4 min-1,0.62(0.39,1.12)×10-4 min-1,Extended Tofts模型计算所得两组的Ktrans值的分别为4.00(1.80,5.99)×10-4 min-1、7.20(4.60,13.20)×10-4 min-1,两种模型计算所得Ktrans值病例组均明显高于对照组,差异有统计学意义(P＜0.001).Patlak模型所得Ktrans值的诊断效能较Extended Tofts模型所得Ktrans值诊断效能高,敏感度为74.36％,特异度94.44％.结论:应用DCE-MRI可以为缺血性脑白质病变发病机制提供重要参考,Patlak模型更适用于评价缺血性脑白质病.

Selection of pharmacokinetic model of DCE-MRI for ischemic white matter disease

Objective:Using dynamic contrast enhanced MRI (DCE-MRI) to evaluate the application value of two different tracer-kinetic models for ischemic white matter disease.Methods:From April to October,2016,fifty-seven subjects were recruited and divided into 2 groups based on the Fazekas score:control group (score 0～ 2,n=18,male/female:10/8) and patients's group (score 3 ～ 6,n=39,male/female:17/22).All of the participants undertook DCE-MR scanning.Patlak model and extended tofts model were used to study the Ktrans value of white matter disease.The difference of Ktrans value between the two groups was conducted using Mann-whitney U test.The sensitivity and specificity of Ktrans value obtained by the two different models were analyzed with receiver operating characteristic (ROC) curve.Results:The Ktrans values obained by Patlak model was 0.20 (0.05,0.31) × 10-4 min-1 and 0.62 (0.39,1.12) × 10-4min-1 respectively for control and patients' group,which was 4.00 (1.80,5.99) × 10-4 min-1 and 7.20 (4.60,13.20)× 10-4 min-1 respectively for the two groups by extended tofts model.The Ktrans values of patients group obtained by the two models were higher than that of control group,with significant difference (P＜0.001).The Ktrans values obtained by Patlak model had the better sensitivity (74.36％) and specificity (94.44％) as compared with that of extended tofts model.Conclusions:Ktrans from DCE-MRI might provide a valuable reference for the pathogenesis of ischemic white matter disease,and the Patlak model is more suitable for the evaluation of ischemic white matter disease.