基于多模态磁共振成像的上肢感觉障碍烟雾病患者大脑SⅠ区重塑模式与机制研究

Moyamoya disease (MMD) is one of the fundamental causes of stroke in adults and children. The incidence of MMD, particularly asymptomatic MMD, increases year after year. Moreover, the incidence of the mismatch between clinical symptoms and hemodynamic compromise is also elevated, which brings troubles to clinicians in determination of the timing of surgery and evaluation of the efficacy of surgery. Many studies have shown that neuroplasticity plays an important role in the functional recovery of MMD patients. Our previous studies showed that in MMD patients undergoing median nerve stimulation, the exacerbation of hemodynamic compromise in the contralateral primary somatosensory cortex (SⅠ) induced changes in the activation of the ipsilateral SⅠ, which probably resulted in functional remodeling. Therefore, we speculate that the cerebral remodeling in MMD patients is closely associated with clinical symptoms. In this study, the multimodal magnetic resonance imaging (MRI) is introduced to investigate the remodeling mode of the SⅠin MMD patients with sensory disturbance, as well as its possible causes and afferent pathways. This study aims to partially reveal the brain functional network-based mechanism for the mismatch between clinical symptoms and hemodynamic compromise in MMD patients, and to further explore the innate protective mechanism of the brain, which will provide a scientific basis for rational determination of the timing of surgery and evaluation of the efficacy of surgery in clinical practice.

烟雾病是成人和儿童发生卒中事件的重要原因之一，其发病率尤其是无症状型烟雾病的发病逐年上升，临床症状与血流动力学损害不匹配的现象也在增多，使临床医生在手术时机的选择和手术疗效的评价上遇到很大困难。大量文献表明神经可塑性在脑卒中患者功能康复中有重要的作用，我们前期的研究也表明烟雾病患者接受正中神经电刺激时随着对侧SⅠ区血流动力学损害的加重，同侧SⅠ区的激活会发生变化，即可能发生了功能重塑。因此，我们推测烟雾病患者的大脑重塑情况与临床症状密切相关。本研究拟利用多模态磁共振成像技术，研究感觉障碍烟雾病患者大脑SⅠ区重塑模式及其可能的诱发因素与传入途径，旨在部分阐明烟雾病患者临床症状与血流动力学损害不匹配的脑功能网络基础，更深层次挖掘大脑的固有保护机制，为临床更科学的选择手术时机与评价手术疗效提供科学依据。

烟雾病是成人和儿童发生卒中事件的重要原因之一，其发病率尤其是无症状型烟雾病的发病逐年上升，临床症状与血流动力学损害不匹配的现象也在增多，使临床医生在手术时机的选择和手术疗效的评价上遇到很大困难，而这种现象的存在可能与大脑SⅠ区的功能重塑相关。本研究通过多模态磁共振成像技术，对健康志愿者、无肢体症状烟雾病患者、肢体感觉异常烟雾病患者大脑SⅠ区及其相关脑功能区术前、术后脑功能及微观结构变化进行了以下研究：①烟雾病患者双侧SⅠ区、胼胝体、丘脑区域BOLD反应的变化特点；②利用DKI技术分析烟雾病患者感觉相关脑区微观结构的变化特点；③以SⅠ区为种子点，研究烟雾病患者感觉相关静息态脑功能网络的变化特点；④基于DKI数据构建全脑功能网络，分析可能与烟雾病患者肢体感觉异常症状相关的脑区节点。结果发现：①感觉异常烟雾病患者无症状侧肢体接受感觉刺激时，同侧SⅠ区、同侧丘脑神经活动增强，同侧SⅠ区活动的增强主要是对肢体感觉异常侧的感觉神经网络起抑制作用；②MMD患者在长期慢性缺血的情况下，脑组织微观结构会发生改变，DKI参数会发生变化，当血流动力学状态稳定时，这些参数也会处于相对稳定或假性正常状态，而当血流动力学进一步损害时，大脑微观结构可能会发生某些急性或者特异性的改变，这些改变会引起DKI参数的变化；③在烟雾病患者脑组织长期缺血状态、双侧脑半球SⅠ区功能连接减弱的背景下，肢体感觉异常烟雾病患者额叶皮层、顶叶皮层与同侧SⅠ区的功能连接增强；④烟雾病患者双侧额中回、额下回三角部与全脑各节点间的连接效率降低，单侧肢体感觉异常烟雾病患者其对侧额中回、额下回三角部与全脑的连接效率较无症状烟雾病患者进一步降低。结果表明，烟雾病患者大脑SⅠ区、额叶皮层、顶叶皮层功能与微观结构变化与烟雾病患者的肢体感觉症状相关，利用多模态MRI可以有效评价大脑功能、结构变化，有助于烟雾病患者的病情及疗效评估。