对高碳酸血症的动态脑血管反应受损预示着白质高信号的发展。
Impaired dynamic cerebrovascular response to hypercapnia predicts development of white matter hyperintensities.
作者信息
Sam Kevin, Conklin John, Holmes Kenneth R, Sobczyk Olivia, Poublanc Julien, Crawley Adrian P, Mandell Daniel M, Venkatraghavan Lakshmikumar, Duffin James, Fisher Joseph A, Black Sandra E, Mikulis David J
机构信息
Department of Physiology, The University of Toronto, Toronto, ON, Canada; Division of Neuroradiology, Joint Department of Medical Imaging, University Health Network, Toronto, ON, Canada.
Division of Neuroradiology, Joint Department of Medical Imaging, University Health Network, Toronto, ON, Canada.
出版信息
Neuroimage Clin. 2016 May 14;11:796-801. doi: 10.1016/j.nicl.2016.05.008. eCollection 2016.
PURPOSE
To evaluate the relationship between both dynamic and steady-state measures of cerebrovascular reactivity (CVR) and the progression of age-related white matter disease.
METHODS
Blood oxygen level-dependent (BOLD) MRI CVR scans were acquired from forty-five subjects (age range: 50-90 years, 25 males) with moderate to severe white matter disease, at baseline and one-year follow-up. To calculate the dynamic (τ) and steady-state (ssCVR) components of the BOLD signal response, the PETCO2 signal waveform was convolved with an exponential decay function. The τ corresponding to the best fit between the convolved PETCO2 and BOLD signal defined the speed of response, and the slope of the regression between the convolved PETCO2 and BOLD signal defined ssCVR. ssCVR and τ were compared between normal-appearing white matter (NAWM) that remains stable over time and NAWM that progresses to white matter hyperintensities (WMHs).
RESULTS
In comparison to contralateral NAWM, NAWM that progressed to WMH had significantly lower ssCVR values by mean (SD) 46.5 (7.6)%, and higher τ values by 31.9 (9.6)% (both P < 0.01).
CONCLUSIONS
Vascular impairment in regions of NAWM that progresses to WMH consists not only of decreased magnitude of ssCVR, but also a pathological decrease in the speed of vascular response. These findings support the association between cerebrovascular dysregulation and the development of WMH.
目的
评估脑血管反应性（CVR）的动态和稳态测量值与年龄相关性白质病变进展之间的关系。
方法
对45名患有中度至重度白质病变的受试者（年龄范围：50 - 90岁，25名男性）在基线和一年随访时进行血氧水平依赖（BOLD）MRI CVR扫描。为了计算BOLD信号响应的动态（τ）和稳态（ssCVR）成分，将PETCO2信号波形与指数衰减函数进行卷积。卷积后的PETCO2与BOLD信号之间最佳拟合对应的τ定义了响应速度，卷积后的PETCO2与BOLD信号之间回归的斜率定义了ssCVR。比较随时间保持稳定的正常外观白质（NAWM）和进展为白质高信号（WMH）的NAWM之间的ssCVR和τ。
结果
与对侧NAWM相比，进展为WMH的NAWM的ssCVR值平均显著降低（标准差）46.5（7.6）%，τ值升高31.9（9.6）%（两者P < 0.01）。
结论
进展为WMH的NAWM区域的血管损伤不仅包括ssCVR幅度降低，还包括血管反应速度的病理性降低。这些发现支持脑血管调节异常与WMH发生之间的关联。
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