中文摘要：

目的应用磁共振弥散张量成像（diffusion tensor imaging，DTI）动态观察脑梗死后颈髓皮质脊髓束的弥散变化，及其与患者神经功能恢复之间的关系，探讨脑梗死后颈髓皮质脊髓束纤维继发性损害及其意义。方法患者分别在的第1周，第4周以及第12周进行DTI检测，每次MRI检测之前采用NIHSS、简式Fugl—Meyer运动功能评分法（FM）和Barthel生活指数（Barthel Index，BI）评定。分别测量颈髓皮质脊髓束的部分弥散各向异性（fractional anisotropy，FA）值与平均弥散量（mean diffusivity，MD）。结果与对照组比较，患者组病灶对侧颈髓皮质脊髓束FA值在各个时间点都明显低于健康对照组第1周：（0．66±0．01，vs，0．71±0．01，P〈0．01），第4周（0．61±0．02，vs，0．69±0．01，P〈0．01），第12周（0．534-0．02，vs，0．69±0．01，P〈0．01），MD值则无明显差异。患者病灶对侧颈髓皮质脊髓束FA值在观察期内变化的百分数与NIHSS、Fugl—Meyer运动评分变化的百分数呈负相关（P〈0．05）。结论局灶性脑梗死引起的皮质脊髓束纤维的继发性损害可以延续到颈髓水平，颈髓皮质脊髓束的继发性损害可能延缓患者神经功能的恢复。

英文摘要：

Objective To investigate the secondary degeneration of corticospinal tracts in cervical spinal cord following a recently cerebral infarct with diffusion tensor imaging （DTI） and its potential impact on neurological recovery. Methods Twenty-six patients with a focal cerebral infract underwent DTI at the first week, the fourth and twelfth week after stroke onset, respectively. The NIH Stroke Scale （NIHSS）, the Fugl-Meyer motor scale （FM） and the barthel index （BI） were used to evaluate the neurological function before every DTI. Twenty-six gender and age match healthy volunteers underwent DTI three times at same time points. The DTI parameters of mean diffusivity （MD） and fractional anisotropy （ FA value） were measured at the cervical spinal cord and initial lesion. Results Compared to the controls, the FA values of the contralateral side corticospinal tracts in the cervical spinal cord in patients significantly decreased at every observed time point （P 〈 0.01 ）. In patients group, the FA values of the contralateral side corticospinal tracts in the cervical spinal cord decreased progressively from 1 s, week to 12th week （P 〈 0. 01 ） , but MD remained unchange. The absolute value of the percent reduction of FA value of the contralateral side corticospinal tracts in the cervical spinal cord in patients associated negatively with the absolute value of the percent change of NIHSS and FM （ P 〈 0. 05 ）, but not with the absolute value of the percent change of BI （ P 〉 0. 05 ）. Conclusions Conclusions ： The secondary degeneration of the corticospinal tracts resulted from cerebral infarction may extend to the cervical spinal cord. Which may last at lest three months and thus hamper the process of neurological recovery.