脑梗死后早期锥体束华勒氏变性的弥散张量成像

摘要

Objective To investigate the feasibility of using diffusion tensor imaging ( DTI) for detection of early Wallerian degeneration of the pyramidal tract after cerebral infarction. Methods Total 23 patients with middle cerebral artery infarction were recruited. All cases were assessed using DTI within 14 days following stroke attack. Quantitative FA and MD were obtained in region of interest ( ROI) in infarction regions, the posterior limb of the internal capsule ( PLIC) and cerehral peduncle ( CP) along the ipsilateral pyramidal tract ( CST) . The indices of FA and MD of the ipsilateral regions were compared with those of matched contralateral regions. Results FA of the ipsilateral CST hegan to decrease at the third day and FA showed decrease in all cases after 7 days following attack. FA values of the affected side were lower in the affected side than in the unaffected side ( ρ＜ 0. 05 ) and MD values were not different between two sides (ρ＞ 0. 05 ) . Conclusions DTI can detect Wallerian degeneration of CST as early as the 3 days after stroke attack.%目的 探讨应用弥散张量成像(diffusion tensor imaging,DTI)检测脑梗死后早期锥体束华勒氏变性的可行性.方法 选取起病14 d内的大脑中动脉区脑梗死患者23例,在入院时行MRI与DTI检查.采用工作站之Functool软件,重建出平均弥散系数(mean diffusivity,MD)、各向异性分数(fractional anisotropy,FA)的参数图.通过放置感兴趣区(region of interest,ROI)的方式获得FA和MD值.ROI放置的部位包括:脑梗死区、脑梗死同侧内囊后支前部和大脑脚,以及上述部位对侧相应区域.结果 最早在起病后第3天即可见脑梗死同侧锥体束FA值下降,自起病7 d后所有患者均出现脑梗死同侧锥体束FA下降,与对侧锥体束FA比率为(0.89±0.09),其差异有统计学意义(P<0.05);脑梗死同侧锥体束MD无明显变化,与对侧锥体束MD比率平均为(0.96±0.10),其差异无统计学意义(P>0.05).结论 DTI可以在脑梗死后早期检测到锥体束的华勒氏变性,最早为发病后第3 d.