医学
烟雾病
白质
心脏病学
异常
磁共振弥散成像
冲程(发动机)
有效扩散系数
磁共振成像
内科学
缺血
放射科
机械工程
精神科
工程类
作者
John Conklin,Jorn Fierstra,Adrian Crawley,Jay Han,Julien Poublanc,Daniel M. Mandell,Frank L. Silver,Michael Tymianski,Joseph A. Fisher,David J. Mikulis
出处
期刊:Stroke
[Ovid Technologies (Wolters Kluwer)]
日期:2010-08-01
卷期号:41 (8): 1610-1616
被引量:89
标识
DOI:10.1161/strokeaha.110.579540
摘要
Reduced cerebrovascular reactivity (CVR) with steal phenomenon is an independent predictor for stroke and may indicate tissue exposed to episodic low-grade ischemia. The apparent diffusion coefficient (ADC) calculated using diffusion-weighted MRI is effective in characterizing focal brain ischemia and subtle structural changes in normal-appearing white matter (WM). We hypothesized that regions of steal phenomenon are associated with increased ADC in normal-appearing WM of patients with Moyamoya disease.Twenty-two patients with unilateral CVR impairment secondary to Moyamoya disease and 12 healthy control subjects underwent diffusion-weighted MRI and functional MRI mapping of the cerebrovascular response to hypercapnia. Parametric maps of ADC and CVR were calculated, coregistered, and segmented using automated image processing methods. ADC of normal-appearing WM was compared between hemispheres, and between WM with negative CVR (ie, steal phenomenon) and WM with positive CVR.In patients, ADC of normal-appearing WM was elevated in the hemisphere ipsilateral to the CVR impairment compared with the contralateral hemisphere (P<0.005) and in WM with negative CVR compared with WM with positive CVR (P<0.001). WM in regions of steal phenomenon within the affected hemisphere had higher ADC than homologous contralateral WM (P<0.005). In control subjects, negative CVR in WM was not associated with elevated ADC.Regions of steal phenomenon are spatially correlated with elevated ADC in normal-appearing WM of patients with Moyamoya disease. This structural abnormality may reflect low-grade ischemic injury after exhaustion of the cerebrovascular reserve capacity.
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