皮质下缺血性血管病患者联络纤维的扩散张量成像分析和认知功能相关研究

【摘要】
目的 运用磁共振成像（magnetic resonance imaging，MRI）基于白质地图的扩散张量成像（diffusion tensor imaging，DTI）技术研究皮质下缺血性血管病（subcortical ischemic vascular disease，SIVD）患者联络纤维的超微结构改变，并分析DTI参数与认知功能的关系。
方法 连续入选40例SIVD患者，分为血管性认知障碍组18例，无认知障碍组22例，另设立20例正常老年人为对照组。对三组进行MRI检查并对其白质改变进行评分，对联络纤维进行基于白质地图分析（atlase based analysis，ABA）DTI成像，比较组间部分各向异性指数（fractional anisotrophy，FA）、平均扩散率（mean diffusivity，MD）差异，并对SIVD患者DTI参数与蒙特利尔认知评估量表（Montreal Cognitive Assessment，MoCA）得分进行相关性分析。
结果 无认知障碍组较正常组在右侧矢状层（下纵束/下额枕束）、右侧扣带（海马部）及左侧上额枕束的FA值减低；认知障碍组较正常组存在广泛的联络纤维FA值降低，差异均具有显著性。无认知障碍组与正常组比较，仅左侧扣带海马部及左侧上纵束MD值无显著差异，余联络纤维的MD值均显著增高；认知障碍组较正常组存在广泛的联络纤维MD值增高，差异均具有显著性。与无认知功能障碍组比较，认知功能障碍组在双侧矢状层（下纵束/下额枕束）、双侧扣带扣带回部、海马部、双侧上纵束、双侧上额枕束及双侧钩束的FA值减低，MD值增高，差异具有显著性。SIVD患者双侧矢状层（下纵束/下额枕束）、扣带扣带回部、上纵束、上额枕束及钩束和左侧扣带海马部的FA值与MoCA评分呈正相关，MD值与MoCA评分呈负相关。
结论 SIVD患者联络纤维的FA值减低，MD值增高，且DTI参数与其认知功能密切相关。

Diffusion Tensor Imaging Analysis of Association Fibers in Patients with Subcortical Ischemic Vascular Disease and Correlations with Cognitive Function

Objective To investigate microstructure changes of association fibers in subcortical ischemic vascular disease （SIVD） patients using atlas-based analyses （ABA） of diffusion tensor imaging （DTI） and clinical correlations of ischemic changes. Methods Forty SIVD patients （18 vascular cognitive impairment VCI] patients and 22 non-cognitive impairment NCI] patients） and 20 normal controls were performed with neuropsychological tests and 3-Tesla magnetic resonance imaging （MRI） including DTI scans. The rating score of white matter change, ABA of the fractional anisotropy （FA） and mean diffusivity （MD） were computed. The correlation between DTI parameters and Montreal Cognitive Assessment （MoCA） scores were evaluated. Results Compared with NCI group, VCI group patients had lower FA value and higher MD value in bilateral sagittal stratum （inferior longitudinal fasciculus/inferior fronto-occipital fasciculus）, cingulate gyrus （cingulum）, hippocampus （cingulum）, superior longitudinal fasciculus, superior fronto-occipital fasciculus, uncinate fasciculus. However, the rating score of white matter change showed no significant difference. In addition, MoCA scores of SIVD patients positively correlatedwith FA values and negatively correlated with MD values of association fibers, including bilateral sagittal stratum （inferior longitudinal fasciculus/inferior fronto-occipital fasciculus）, cingulate gyrus （cingulum）, superior longitudinal fasciculus, superior fronto-occipital fasciculus, uncinate fasciculus and left hippocampus （cingulum）. Conclusion FA values increase and MD values decrease in association fibers of SIVD patients Moreover, it is significantly related with cognitive function.