Functional Neuroimaging Laboratory, Faculty of Science and IT, School of Psychology, University of Newcastle Newcastle, NSW, Australia ; Centre for Translational Neuroscience and Mental Health Research, University of Newcastle Newcastle, NSW, Australia ; Hunter Medical Research Institute Newcastle, NSW, Australia.
Front Hum Neurosci. 2013 Nov 18;7:782. doi: 10.3389/fnhum.2013.00782. eCollection 2013.
Increased cerebral blood flow pulsatility is common in vascular dementia and is associated with macrostructural damage to cerebral white matter or leukoaraiosis (LA). In this study, we examine whether cerebral blood flow pulsatility is associated with macrostructural and microstructural changes in cerebral white matter in older adults with no or mild LA and no evidence of dementia. Diffusion Tensor Imaging was used to measure fractional anisotropy (FA), an index of the microstructural integrity of white matter, and radial diffusivity (RaD), a measure sensitive to the integrity of myelin. When controlling for age, increased arterial pulsation was associated with deterioration in both measures of white matter microstructure but not LA severity. A stepwise multiple linear regression model revealed that arterial pulsatility index was the strongest predictor of FA (R = 0.483, adjusted R (2) = 0.220), followed by LA severity, but not age. These findings suggest that arterial pulsatility may provide insight into age-related reduction in white matter FA. Specifically, increased arterial pulsatility may increase perivascular shear stress and lead to accumulation of damage to perivascular oligodendrocytes, resulting in microstructural changes in white matter and contributing to proliferation of LA over time. Changes in cerebral blood flow pulsatility may therefore provide a sensitive index of white matter health that could facilitate the early detection of risk for perivascular white matter damage and the assessment of the effectiveness of preventative treatment targeted at reducing pulsatility.
大脑血流搏动增加在血管性痴呆中很常见，并且与脑白质的宏观结构损伤或脑白质疏松症（LA）有关。在这项研究中，我们研究了在没有或仅有轻度 LA 且没有痴呆迹象的老年患者中，大脑血流搏动是否与脑白质的宏观和微观结构变化有关。弥散张量成像用于测量各向异性分数（FA），这是白质微观结构完整性的指标，以及辐射扩散率（RaD），这是测量髓鞘完整性的指标。当控制年龄因素时，动脉搏动增加与白质微观结构的两个测量值的恶化都有关，但与 LA 严重程度无关。逐步多元线性回归模型表明，动脉搏动指数是 FA 的最强预测因子（R=0.483，调整后的 R（2）=0.220），其次是 LA 严重程度，而不是年龄。这些发现表明，动脉搏动性可能为与年龄相关的白质 FA 减少提供了深入的见解。具体来说，增加的动脉搏动性可能会增加血管周围的剪切力，并导致血管周围少突胶质细胞的损伤积累，从而导致白质的微观结构变化，并随着时间的推移导致 LA 的增殖。因此，大脑血流搏动性的变化可能提供了一个敏感的白质健康指标，可以促进血管周围白质损伤风险的早期检测，并评估针对降低搏动性的预防治疗的效果。
