磁共振弥散张量成像和弥散张量纤维束成像诊断弥漫性轴索损伤

目的评价联合应用磁共振弥散张量成像(DTI)与弥散张量纤维束示踪技术(DTT)诊断弥漫性轴索损伤(DAI)的价值。方法对14例临床确诊弥漫性轴索损伤病例及14例健康志愿者进行MR平扫、弥散加权成像(DWI)、DTI及DTT检查,测量全部受检者胼胝体及脑干的ADC值和FA值,并进行对比分析。结果DTI显示DAI患者除胼胝体膝部外的其他测量区域FA值均明显减低(P<0.01)。ADC值可早期发现DAI的脑部损伤水肿区,但量值随发病时间变化较大;DTT结合弥散张量椭球体图可很好显示感兴趣区白质纤维束,在某种程度上更直观地显示脑白质受损范围。结论DTI联合DTT是目前在活体中诊断与评估弥漫性轴索损伤最敏感、准确的检查方法,并可用于动态观察神经纤维的临床转归过程,提示患者预后。

Combination of MR diffusion tensor imaging and diffusion tensor tracking in diagnosis of diffuse axonal injury

Objective To explore the value of the combination of diffusion tensor imaging(DTI)and diffusion tensor tracking(DTT)technique in the diagnosis of diffuse axonal injury(DAI).Methods MRI data including T1WI,T2WI,T2WI,DWI,ADC value,FA value,diffusion tension figure and DTI figure were obtained in 14 cases of DAI and 14 control subjects,and ADC,FA value of corpus callosum and brainstem were measured.Results DTI showed that FA value turned down obviously in most areas except the genu of corpus callosum in all DAI patients,obviously lower than that of controls(P<0.01).Edema areas of DAI patients were detected in the earlier period by ADC value,but the values changed obviously in different periods.Combination of DTT and diffusion tensor ellipsoid showed offending alba fiber bundle well,depicting lesions of alba area more directly to some extent.Conclusion Combination of DTI and DTT is the most sensitive and accurate method to diagnose and evaluate DAI.It can be used to observe the clinical turnover of nerve fiber and imply the prognosis,especially in the dynamic diagnosis of DAI in vivo.