II型糖尿病神经元凋亡低氧影响机制的MRI结构及功能成像研究

II型糖尿病患者相比正常人群更容易发生脑萎缩及相应的功能改变，而神经元凋亡是造成全脑或局部脑萎缩的直接原因；患者普遍存在脑微血管病变，引起脑血流降低，继而出现慢性低氧状态。然而，长期低氧状态是否直接影响神经元凋亡以及影响程度尚不清楚，而且缺乏在体研究依据。本课题组在国内首先利用磁敏感加权成像（SWI）测量脑内静脉φ值来推算脑氧摄取分数（OEF），并在改进的定量磁敏感成像（QSM）上得到了更准确的OEF值。基于课题组前期丰富的工作基础，本课题拟用3D ASL、QSM、DKI及静息态功能成像技术对II型糖尿病家兔模型及患者进行多时间点动态扫描，从脑血流、氧代谢、灰白质结构和功能改变等多个方面进行综合定量分析，并与临床资料、病理免疫组化指标进行关联性分析，以期获得低氧与神经元凋亡的关系，并探求有力的评估糖尿病脑结构、功能改变的MRI指标。

Compared to the healthy people, the patients with Type II diabetes are more prone to cerebral atrophy and the corresponding function change. Neuronal apoptosis is the immediate cause of global or local cerebral atrophy. Cerebral small vascular diseases are common in patients with Type II diabetes, which may causes decreased cerebral blood flow, followed by chronic hypoxia. However, whether long-term hypoxia directly affects the apoptosis of neurons and the degree of influence is not clear. Moreover, the evidence of corresponding research in vivo is still lack. Our group first measured cerebral vein φ value to calculate cerebral oxygen extraction fraction (OEF) by susceptibility weighted imaging (SWI) and then got more accurate OEF value from the improved quantitative susceptibility mapping (QSM). On the basis of our previous research, this project intends to explore the effective MRI metrics which can evaluate the brain structural and functional changes in patients with Type II diabetes. In order to obtain the relationship between hypoxia and apoptosis of neurons, dynamic MRI scanning is performed on rabbit models and patients of type II diabetes with 3D ASL, QSM, DKI and resting-state functional sequences. Furthermore, Comprehensive quantitative analysis is also performed from cerebral blood flow, oxygen metabolism, structural and functional changes. Besides, we also explore the new and effective markers to assess the cerebral structural and functional changes with analyzing the correlation between MRI and clinical, pathological-immunohistochemical index.