磁共振弥散张量成像研究脑桥梗死后神经纤维华勒变性及临床意义

A sequence investigation on Wallerian degeneration after pontine infarction with diffusion tensor imaging

目的采用磁共振弥散张量成像(diffusion tensor imanging,DTI)动态观察脑桥梗死后,远离梗死灶的延髓及小脑中脚神经纤维华勒变性及其对患者神经功能恢复的影响。方法选择单侧脑桥梗死患者14例,以及年龄性别相匹配的健康志愿者14名作对照组。分别在发病第1、4、12周进行 DTI 检测,并行美国国立卫生研究院卒中评分(National Institutes of Health stroke scale,NIHSS)、简式 Fugl-Meyer 运动功能评分(Fugl-Meyer motor scale,FM)、共济失调评分(ataxia rating scale,ARS)和Barthel 生活指数(Baahel index,BI)评分。结果与对照组比较,患者梗死灶同侧延髓及双侧小脑中脚的部分弥散各向异性值(fractional anisotropy,FA)从第1周至第12周逐渐减少(延髓梗死同侧 FA值:第1周0.43±0.01;第4周0.37±0.02;第12周0.30±0.02,小脑中脚梗死同侧 FA 值:第1周0.50±0.02;第4周0.43±0.02;第12周0.35±0.04,小脑中脚梗死对侧 FA 值:第1周0.54±0.02;第4周0.52±0.03;第12周0.47±0.04,t=1.92～28.56,均 P<0.05),而平均弥散量(meandiffusivity,MD)的变化差异却无统计学意义(P>0.05)。在观察期间,患者梗死灶同侧延髓及双侧小脑中脚的 FA 值减少的百分数绝对值与同期 NIHSS 及 BI 变化的百分数绝对值呈负相关(P<0.05)。结论局灶性脑桥梗死后,同侧延髓及双侧小脑中脚神经纤维的华勒变性持续存在,并且可能阻碍患者神经功能的恢复。

Objective To investigate the Wallerian degeneration of neural fiber tract in medulla and bilateral middle cerebellar peduncle following pontine infarction and to explore its impacts on neurological recovery. Methods Fourteen patients with a recent unilateral pontine infarct underwent the diffusion tensor imaging （DTI） and evaluations with the NIH stroke scale （NIHSS）, the Fugl-Meyer motor scale （FM）, ataxia rating scale （ARS） and the Barthel index （BI） at the first week （W1）, the fourth （W4） and twelfth week （W12） respectively. Mean diffusivity （MD） and fractional anisotropy （FA） were measured at pens, medulla and middle cerebellar peduncle. Fourteenth age and gender matched volunteers underwent a DTI were studied as controls. Results Compared with the matched regions in controls, the FA values of infarct side medulla and bilateral middle cerebellar peduncle in patients significantly decreased at W1, W4 and W12 （ on the infarct side of medulla：W1：0.43 ± 0.01 ; W4：0.37 ± 0.02 ; W12：0.30 ± 0.02 ; on the infarct side of middle cerebellar peduncle： W1：0.50 ±- 0.01 ; W4：0.43 ± 0.02 ; W12：0.35 ± 0.04 ; on the opposite side of middle cerebellar peduncle infarction：W1：0.54 ± 0. 02; W4：0.52 ± 0. 03; W12：0. 47 ± 0.04,t values are 1.92 to 28. 56, P 〈0.05 respectively）, with the MD of these regions not significantly modificated during the same time （ P 〉0.05 respectively）. The absolute value of percent reduction of FA in infarct side medulla and bilateral middle cerebellar peduncle was correlated negatively to the absolute value of percent change of NIHSS and BI score （ P 〈 0. 05 respectively）. Conclusions The Wallerian degeneration in infarct side medulla and bilateral middle cerebellar peduncle following a unilateral pontine infarct will persist at least for twelve weeks, and it may hamper the neurological recovery.