缺血性脑白质病变对认知功能的影响及其机制的神经影像学研究

缺血性脑白质病变是引起血管性认知功能障碍的主要原因之一，然而其发生机制目前仍不清楚。本课题组基于前期对脑白质疏松症患者的神经心理学评估、神经影像学评估（弥散张量成像、磁共振波谱分析、静息态核磁共振）等研究，发现脑白质疏松症患者存在明显的认知功能障碍，且与上述影像学指标（如FA值、MD值）存在明显的相关性。然而，脑白质疏松症患者基于全脑水平的灌注和代谢情况目前尚不明确，因此，本项目拟采用脉冲式动脉自旋标记技术（pulsed arterial spin labeling，PASL），以及正电子发射体层扫描技术(positron emission tomography，PET)观察不同程度、不同病变部位的缺血性脑白质病变患者的脑灌注及代谢状态。本项目的实施，将从多模态的神经影像角度揭示缺血性脑白质病变患者的认知神经机制，并为重大神经精神疾病的早期临床辅助诊断、预警提供重要的科学依据。

Ischemic white matter lesions(IWML) is one of the most common cause of vascular cognitive impairment or even vascular dementia. However, the mechanisms of such cognitive impairment have not been well elucidated. Our extensive prior studies on leukoaraiosis using the methods of neuropsychological tests, neuroimaging examinations (e.g., diffusion tensor imaging, magnetic resonance spectroscopy and resting state fMRI) have shown that patients with leukoaraiosis are related with comprehensive cognitive function deficits, especially in the domains of attention, memory, executive function and information processing speed. Furthermore, such cognitive impairment were correlated with the values of fractional anisotropy (FA), mean diffusivity (MD). However, the changes of brain perfusion or metabolism underlying in patients with leukoaraiosis are not yet well understood. The aim of this study is to elucidate the relationship between white matter integrity and gray matter metabolism using pulsed arterial spin labeling (PASL) and fluorodeoxyglucose-positron emission tomography (FDG-PET) in a cohort of patients with leukoaraiosis. We hypothesized that there was a link between white matter degeneration and gray matter hypoperfussion or hypometabolism in patients with leukoaraiosis. Our study may be contributed to elucidate the neuro-mechanism of the cognitive dysfunction in patients with leukoaraiosis, and also may be helpful to screen individuals of high risk of vascular dementia and to provide an important information for the early clinical diagnosis or warning for neuropsychiatric disorders.