3.0T MR DTI及DTT对正常青年人腕管内正中神经的定量分析

目的 运用扩散张量成像(DTI)定量分析健康青年人腕管内正中神经(MN)部分功能参数值特点及扩散张量纤维束成像(DTT)重建MN纤维束.方法 采用3.0T MR对25名健康志愿者行腕部常规MR及DTI序列扫描,测量DTI各参数值并重建MN纤维束.结果 ①MN各向异性分数(FA)值=0.686±0.089、MN轴向扩散系数(AD)值=(2.085±0.263)mm2/s、MN径向扩散系数(RD)值=(0.568±0.151)mm2/s、MN平均扩散率(ADC)值=(1.073±0.140)mm2/s.②各层面FA、RD值之间存在显著差异(P<0.05),各层面AD、ADC及各本征值E1、E2、E3之间差异无统计学意义(P>0.05).③腕管内MN从近心端到远心端DTI各部分功能参数均有不同的变化趋势.④MN FA、MN AD、MN RD、MN ADC的95%置信区间上下限分别为(0.675,0.698)、(2.052,2.117)、(0.549,0.587)、(1.056,1.091).⑤利用DTT可以完整地重建显示MN纤维束,远端分支亦能显示.结论 应用DTI及DTT技术可以定量描述MN的FA及直观显示重建的MN纤维束,可为诊断MN病变提供定量的观察指标.

Quantitative analysis of the median nerve in the carpal tunnel of healthy volunteers by using DTI and DTT at 3.0T MR

Objective To quantitative analyze the median nerve(MN)in the carpal tunnel of healthy youth by using diffusion tensor imaging(DTI),and diffusion tensor tractography(DTT)for reconstruct of fiber tract.Methods MR examinations at 3.0T including DTI were conducted on wrists in 25 healthy subjects in order to measure the DTI parameters and to reconstruct the fiber tract of the MN.Results ① Mean values of FA,AD,RD and ADC of the MN were 0.686±0.089,(2.085±0.263)mm2/s,(0.568±0.151)mm2/s and (1.073±0.140)mm2/s respectively.② Significant statistic differences were found between FA,RD values of different planes (P<0.05).AD,ADC,E1,E2 and E3 values were not significantly different in statistics (P>0.05).③ The DTI parameters ap-peared different trends in the aspect of the MN from proximal to distal in the carpal tunnel.④The 95% confidence interval of MN FA,MN AD,MN RD and MN ADC were 0.675-0.698,2.052-2.117,0.549-0.587 and 1.056-1.091 respectively.⑤ A complete structure of MN were visualized by using DTT,and the distal branches were also visualized well.Conclusion DTI and DTT are use-ful tools to reconstruct MN,providing quantitative information for the diagnosis of MN diseases.