脑梗死继发皮质脊髓束Wallerian变性的DTI动态研究

DTI dynamic research of Wallerian degeneration in corticospinal tracts after cerebral ischemic infarction

目的:探讨磁共振扩散张量成像(DTI)监测脑梗死后皮质脊髓束Wallerian变性的可行性。方法:45例符合纳入标准的脑梗死患者分别于发病10天内及发病后第30和90d时进行3次全脑常规MRI和DTI数据采集,利用Fiber Track工具测量双侧大脑脚底的ADC和FA值,并计算相对ADC值(rADC)和相对FA值(rFA)。结果:MR DTI显示脑梗死发病(5.3±2.6)d后患侧大脑脚底的FA值降低,发病后首次及第30和90d时梗死侧大脑脚底FA值较对侧分别降低9.90%、23.7%和20.7%,差异均具有统计学意义(P<0.05)。梗死侧大脑脚底ADC值随时间延长而轻度升高,但与对侧比较差异均无统计学意义(P>0.05)。结论:DTI定量参数(ADC和FA)可以反映皮质脊髓束Wallerian变性的动态病理变化。DTI在脑梗死发病后5天左右即可检测出皮质脊髓束Wallerian变性,是监测脑白质微观结构早期改变的敏感方法。

Objective:To explore the feasibility of MR diffusion tensor imaging(DTI)for monitoring Wallerian degeneration of corticospinal tracts after cerebral ischemic infarction.Methods:All forty-five patients met the inclusion criteria with cerebral infarction underwent repeatedly head MRI scanning and whole brain DTI data acquisition at time of within 10 days,and 30 and 90 days after infarction onset.DTI quantitative parameters including ADC and FA values were measured at the base of cerebral peduncle(BCP).Results:MR DTI examination showed the FA values of BCP at affected side began to decrease several days after infarction onset,the averaged time was 5 days.Compared with the unaffected side,the FA values of BCP at affected side in the first scan and 30 and 90 days after cerebral infarction decreased 9.90%,23.7%and 20.7%respectively,there were significantly statistical diffe-rence(P<0.05);the ADC values of BCP on affected side showed gradually increase at the three time points,but no significantly statistical difference existed(all P>0.05).Conclusion:DTI quantitative parameters(ADC and FA)can reflect the dynamic pathological changes of Wallerian degeneration in corticospinal tract.MR DTI could detect Wallerian degeneration of corticospinal tract as early as 5 days averaged after infarction onset,it is a sensitive method for monitoring microstructure change of cerebral white matter.