基于多模态影像融合技术的颈动脉狭窄患者脑网络与认知功能研究

Changes in brain networks and cognitive function in patients with carotid stenosis were not clear. Based on previous studies, we found that hypoperfusion caused by carotid stenosis can lead to cognitive impairment. And carotid endarterectomy can improve the cognitive function of patients. Another study found that stroke can cause brain network damage, which can lead to cognitive impairment. So we proposed to use diffusion tensor imaging technology, resting state fMRI, task based fMRI and the brain network fusion technology to establish a multimodal fusion network of carotid stenosis patients. Combined with cognitive function estimate and brain cerebral perfusion evaluation, in comparison with healthy adult controls can we find changes in patients brain network and cognition. To identify the relationship between the impaired cognitive function and the damaged brain network, we can discover the potential cognitive brain circuits. At the same time, the brain network, cerebral perfusion and cognitive function changes before and after the operation were compared, and the cognitive functional brain circuits found before were further verified. This experiment provides a theoretical basis for the treatment strategies of patients with carotid artery stenosis with cognitive dysfunction. And provides evidence for brain cognition and brain network study in future.

目前颈动脉狭窄患者的脑网络及认知功能改变及其机制并不明确。我们前期研究发现颈动脉狭窄所致脑低灌注可引起认知功能损害，而颈动脉内膜剥脱手术可改善患者认知功能。同期研究中本课题组发现脑卒中可造成患者脑网络破坏，进而引起认知功能损害。所以我们拟应用脑网络融合技术分析、处理弥散张量成像（DTI）、静息态功能磁共振（rs-fMRI）、任务态功能磁共振（task-fMRI）扫描颈动脉狭窄患者所得的脑网络影像数据，建立颈动脉狭窄患者的多模态融合脑网络，结合脑认知功能检查及脑灌注评估，与健康成人对比研究，明确颈动脉狭窄患者认知功能及其脑网络发生的改变；探明部分受损认知功能与被破坏脑网络的关联关系，发现潜在的认知脑环路；同时分析患者手术后脑网络、脑灌注及认知功能改变情况，验证前期研究发现的认知功能脑环路。为颈动脉狭窄伴认知功能障碍患者的治疗策略提供理论基础，为认知功能研究、脑网络研究提供支持。

颈动脉狭窄患者存在认知功能损害，本课题组前期的结果提示低灌注、脑梗死及患者脑网络的改变是造成这一现象的主要机制。在此基础上，本课题组采用多模态磁共振技术结合全面的认知功能测试对无梗死型颈动脉狭窄患者认知损害的机制进行深入研究。我们的研究发现，患者的记忆、语言和执行能力存在显著损害。与之对应，患者前循环区域皮层、额顶叶白质纤维存在显著损害、额叶静息状态下的神经活动减弱；患者记忆能力的下降主要和左侧额叶下回和额中回萎缩相关，而额上回、颞上回、楔前叶、扣带回等语言网络区域的任务态功能活动异常则与患者语言功能受损相关。此外，本课题组还观察到，颈动脉狭窄患者的认知能力改变存在异质性，少部分患者认知功能损害不显著。针对这一现象，本课题组发现，较高的教育程度和有效的Willis环代偿是颈动脉狭窄患者认知功能的保护因素，高龄则是认知损害的危险因素。而且，相较于认知功能保留的患者，认知能力显著受损患者额叶的脑白质结构明显受损，且狭窄对侧的损害范围较狭窄侧广泛。本课题组的研究结论从脑结构、功能及网络的角度揭示了颈动脉狭窄患者认知功能受损的机制，拓展了多模态磁共振成像及认知领域的研究内容，为保护颈动脉狭窄患者认知功能、提高其生活质量提供理论基础。