White matter structural integrity and transcranial Doppler blood flow pulsatility in normal aging
White matter structural integrity and transcranial Doppler blood flow pulsatility in normal aging
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DOI：
10.1016/j.mri.2017.11.003
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发表时间：
2018-04-01
影响因子：
2.5
通讯作者：
Derby, Carol A.
中科院分区：
文献类型：
--
作者：
Fleysher, Roman;Lipton, Michael L.;Derby, Carol A.
脑血管疾病是许多形式的与年龄相关的认知障碍的基础，假设将两者联系起来的机制涉及白质（WM）完整性的不利变化。尽管是全身性的，但小血管疾病并不总是影响WM。我们对MRI图像进行体素分析，以检查分数各向异性(FA) - WM结构完整性的扩散张量测量-和脉搏指数(PI) -经颅多普勒超声测量异常动脉流量-在70岁以上无中风和痴呆的成年人中。我们证明了PI与WM微结构变化的关系是动脉特异性和区域性的。我们发现了PI升高和FA降低之间存在显著相关性的空间集群，这不能用衰老来解释，支持了WM损伤的血管假说。这些区域并不局限于评估PI的血管区域，这表明PI和FA之间的联系不太可能是灌注本身的功能，而是与脉动血管壁发出的机械波引起的损伤一致。
Cerebrovascular diseases underlie many forms of age-related cognitive impairment and the mechanism linking the two is hypothesized to involve adverse changes in white matter (WM) integrity. Despite being systemic, small vessel disease does not uniformly affect WM. We performed voxel-wise analysis of MRI images to examine the association between fractional anisotropy (FA) - a diffusion tensor measure of WM structural integrity - and pulsatility index (PI) - a transcranial Doppler ultrasound measure of abnormal arterial flow - in adults over the age of 70 years who were free of stroke and dementia. We demonstrate that the relation of PI to microstructural changes in WM is artery specific and regional. We identified spatial clusters of significant correlations between elevated PI and reduced FA which cannot be explained by aging, supporting a vascular hypothesis of WM injury. These areas are not limited to the vascular territories of the vessels where PI is assessed, suggesting that the linkage between PI and FA is not likely a function of perfusion per se, but is consistent with injury caused by mechanical wave emanating from pulsating vessel walls.