磁共振成像和弥散张量成像评价缺血性脑卒中患者皮质运动功能激活状态及皮质脊髓束异常与肌力的关系

Evaluating the activated status of cortical motor function and the relationship of abnormality of cortical spinal tract and muscular strength in patients with cerebral ischemic stroke by using fMRI and diffusion tensor imaging

目的:应用磁共振成像和弥散张量成像观察缺血性脑卒中急性期患者皮质运动功能及皮质脊髓束的异常,评估皮质脊髓束受损与肌力的关系。方法:实验于2005-08/2005-12在解放军南京军区福州总医院完成。对9例缺血性脑卒中急性期患者和9例健康志愿者进行磁共振成像及弥散张量成像检查。缺血性脑卒中诊断符合中国现行脑血管病诊断标准,临床表现以偏瘫为主,所有患者均知情同意。①磁共振成像应用组块设计,以被动对指运动作为刺激任务,静息状态作为基线任务。设备采用GE1.5T磁共振成像系统,所有数据进行离线后处理,应用SPM2软件处理磁共振成像图像,观察皮质运动功能激活状态。②弥散张量成像采用dTV.Ⅱ软件进行处理,显示各向异性图及彩色各向异性方向图,并重建患者的双侧皮质脊髓束三维纤维图。③应用Brunnstorm标准判断脑卒中患者患手肌力。结果:9例患者和9例健康志愿者的数据值均进入结果分析。①磁共振成像表现结果:7例脑卒中患者患手运动时,对侧半球的感觉运动皮质可见微弱激活,而在同侧后顶叶皮质见到明显激活。3例患者可见小脑激活状态。2例出现患手运动时,双侧感觉运动皮质激活,且同侧激活区域大于对侧。健手运动时,激活对侧感觉运动皮质及后顶叶皮质及对侧辅助运动区,同侧未见明显激活区。②弥散张量成像表现结果:9例脑梗死患者梗死区各向异性值均较对侧降低,两侧具有显著性意义(t=4.570,P<0.001)。梗死区各向异性值与对侧肌力有明显相关性(rs=0.888,P<0.05)。③皮质脊髓束表现结果:双侧皮质脊髓束重建,健侧解剖形态与正常人大致相吻合,自中央前回下行至内囊并延续至脑桥和延髓,每条连续形态一致性良好。患侧皮质脊髓束因受梗死区不同程度的累及,表现为连续性中断及解剖结构形态一致性的丧失。皮质脊髓束损伤程度与患手肌力明显相关(rs=0.888,P<0.05)。结论:①脑卒中患者患手运动时磁共振成像表现与正常人不同,提示存在脑功能代偿与重组。②皮质脊髓束损伤程度与肌力相关,可用于判断康复治疗的预后。

AIM： To observe the cortical motor function and cortical spinal tract abnormalities with fMRI and diffusion tensor imaging （DTI） in patients with acute cerebral ischemic stroke, and evaluate the relationship between the impairment of cortical spinal tract and muscular strength. METHODS： The study was carried out in the Fuzhou General Hospital of Nanjing Military Area Command of Chinese PLA between August and December 2005. Nine patients with acute cerebral ischemic stroke and 9 healthy volunteers were examined with fMRI and DTI. The diagnosis of cerebral ischemic stroke was in accordance with the diagnostic standard for cerebrovascular disease used in China at present, and the main clinical manifestation was hemiplegia, and all the patients agreed to participate in the study. ① A block-based design was used in the fMRI, the passive finger clenching paradigm was taken as the stimulative task, and the rest status was considered as the baseline task. The GE 1.5 T fMRI systems, and all the data were given off-line treatment. The activated status of cortical motor function was observed with the SPM2 software treated fMRI. ② The DTI was treated wit the dTV-Ⅱ software, and showed fractional anisotropy and color fractional anisotropy maps, the 3-dimensional tractography of bilateral cortical spinal tracts of all patients were created. ③ The muscular force of the affected hand of the stroke patients was evaluated with the Brunstorm criteria. RESULTS： The data of all the 9 patients and 9 healthy volunteers entered the analysis of results. ① The results of fMRI： Contralateral sensorimotor cortexes were weakly activated in 7 stroke patients during the affected hand movement, and obviously activated in ipsilateral posterior parietal cortex. Cerebellum was activated in 3 cases. Bilateral sensorimotor cortexes were activated in 2 stroke patients during the affected hand movement, and the activated area in the ipsilateral side was greater than that in the contralateral one. During the good hand movement, the contralateral sensorimotor cortex and posterior parietal cortex and ipsilateral assistive movement area were activated, which were not observed in the ipsilateral side. ②DTI results： The fractional anisotropy value in the infarcted area was significantly lower than that in contralateral side （t=4.570, P 〈 0.001）. The fractional anisotropy value in the infarcted area was obviously correlated with contralateral muscular strength of hand （r=0.888, P 〈 0.05）. ③ Resuits of cortical spinal tracts： Bilateral cortical spinal tracts were recon-structed, the contralateral anatomical form was consistent with that of normal people, and there was consistency of continuous form of each line from precentral gyrus down to internal capsule and prolonged to pontine and medulla oblongata. The ipsilateral cortical spinal tract showed continuous breaks and loss of anatomic structure consistency for the involvement of infarcted area to different extent. The injured severity of cortical spinal tract was obviously correlated with the muscular strength of the affected hand （r=0.888, P 〈 0.05）. CONCLUSION： ① The fMRI manifestations of stroke patients was different from that of normal people, suggesting that there is brain compensation and recombination.② The injured severity of cortical spinal tract was correlated with the muscular strength, which might predict the prognosis of rehabilitative treatment.