【作者】 王晶；

【导师】 童善保； 李瑶；

【作者基本信息】 上海交通大学 ， 生物医学工程， 2018， 硕士

【摘要】 研究表明卒中病人的运动康复伴随着大脑结构与功能的重塑过程,如健侧皮层区域的异常激活,患侧纤维束弥散特性的变化,运动控制的功能性转移等。然而,由于现有研究的卒中病灶较为分散,研究康复时段不统一,以及研究方法的差异,卒中后运动康复的机理与预测性标识还未取得一致性结论。皮质脊髓束(Corticospinal Tract,CST)在运动调控方面发挥着重要作用,前人的研究表明缺血性卒中患者的CST结构变化与运动受限有关。基底节的损伤不仅导致CST的完整性受到破坏,而且对于亚皮层运动相关的脑区也有着直接的影响。本文旨在应用双模态影像数据,探究卒中病人康复过程不同时期的CST通路,基底节-丘脑-皮层通路,小脑-丘脑-皮层通路的动态变化,以及这三个通路和运动康复的联系。本研究通过选取病灶局限在基底节区域的14例病人来研究运动康复的动态变化,分别在2周内(急性期,S1),1-3月(恢复早期,S2),3月以后(恢复期,S3)这三个阶段进行弥散张量成像(Diffusion Tensor Imaging,DTI)数据,功能磁共振成像(functional Magnetic Resource Imaging,fMRI)数据,和临床运动评分的采集。其中fMRI影像采集中病人需使用上肢执行手动运动任务,选取分析的感兴趣区域为双侧的大脑脚,内囊后肢,后放射冠,小脑,丘脑,扣带回,主运动区,运动前区,以及辅助运动区。本文计算了CST通路上所有感兴趣区域的弥散系数,以及运动相关脑区的激活水平,并与临床运动评分进行了相关分析。DTI分析结果表明双侧CST的不对称性在整个研究时长内持续性增大,且恢复早期的不对称指标与同期的运动评分相关,说明了CST通路的完整性对于保持良好运动功能的重要性。在急性期,健侧CST通路上主要纤维束的各向异性(Fractional Anisotropy,FA)与恢复早期的运动评分负相关,侧面证实了患侧CST通路的受损程度决定了后续的运动表现。fMRI结果表明双侧小脑激活的不对称性与运动行为评分存在相关关系,急性期健侧小脑的主导性越强,运动表现越好,而恢复早期患侧小脑的主导性与运动评分正相关,表明了小脑在不同运动康复阶段中的功能改变。恢复早期的双侧扣带回显著激活预测着运动功能的康复程度,被解释为注意力调控同样参与运动控制。本研究对于卒中后的运动康复进行纵向研究,验证了基底节卒中病人在以上三个运动通路上存在异常的假设,并发现了与运动功能相关的预测性影像指标,对于有针对性的康复治疗提供了影像学参考依据。更多还原

【Abstract】 Previous studies have shown that structural and functional cerebral reorganization exist during motor recovery of stroke patients,including recruitment of contralesional motor areas,diffusion changes of ipsilesional fiber bundles,functional activation shift of motor control,etc.However,due to the variety of lesion sites,recovery sessions and imaging methods,there is no consistent conclusion of motor recovery mechanism and effictive neuroimaing biomarkers were rately identified across motor recovery in stroke.As an important pathway of motor execution,corticospinal tract(CST)has shown structural changes on stroke patients and the changes are correlated with motor dysfunction.Damage on basal ganglia(BG)not only affect CST integrity,but also has direct impact on cerebellum(CB)and thalamus,both of which involve motor control and motor learning.We combined Diffusion Tensor Imaging(DTI)and functional Magnetic Resource Imaging(fMRI)methodologies to investigate dynamic changes of CST pathway,BG-thalamus-cortical loop,CB-thalamus-cortical loop as well as the correlation of these loops along with motor recovery.We recruited 14 ischemic stroke patients with lesion in BG area to study brain structural and functional changes during motor recovery.Each of the patient performed DTI and fMRI scan for 3 sessions,i.e.within 2 weeks(acute stage,S1),1-3 months(early stage,S2),over 3 months(chronic stage,S3)after stroke.Fugl-Meyer(FM)motor assessment was also acquired and finger-tapping task was performed during fMRI scanning.Regions of interests in this study include bilateral cerebral peduncle(CP),posterior limb of internal capsule(PLIC),superior carona radiate(s CR),cerebellum,thalamus,cingulate gyrus,primary motor area,premotor cortex,and secondary motor area.We calculated diffusion parameters of CST pathway as well as activation level of motor-related regions,and perfomed correlation analysis between them and FM score.From our DTI results,the lateralization of bilateral CST fractional anisotropy(FA)value was positively correlated with FM score during S2,indicating the importance of CST integrity in maintaining good motor function.The FAs in contralesional CP and PLIC during S1 were associated with changes of FM score,showing that motor recovery was dependent on the damage degree of ipsilesional CST.The fMRI results showed CB functional lateralization correlated with motor recovery.The more contralesional dominance of CB activation at S1,the better motor recovery is at S2;whereas S2 showed the opposite trend to predict S3 stage motor function.Significant activation of cingulate gyrus during S2 predicted functional motor recovery of S3,implying the role of attentional modulation.The longitudinal study on motor recovery after stroke consolidates the hypothesis that basal ganglia stroke patients dysfunction in the three mentioned loops.The neuroimaging biomarkers showing significant correlation with motor recovery provide informative target for effective therapeutic intervention.更多还原