MGH/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA.
Neuroimage. 2011 Mar 15;55(2):468-78. doi: 10.1016/j.neuroimage.2010.12.032. Epub 2010 Dec 16.
Prior studies have demonstrated decreasing cerebral blood flow (CBF) in normal aging, but the full spatial pattern and potential mechanism of changes in CBF remain to be elucidated. Specifically, existing data have not been entirely consistent regarding the spatial distribution of such changes, potentially a result of neglecting the effect of age-related tissue atrophy in CBF measurements. In this work, we use pulsed arterial-spin labelling to quantify regional CBF in 86 cognitively and physically healthy adults, aged 23 to 88 years. Surface-based analyses were utilized to map regional decline in CBF and cortical thickness with advancing age, and to examine the spatial associations and dissociations between these metrics. Our results demonstrate regionally selective age-related reductions in cortical perfusion, involving the superior-frontal, orbito-frontal, superior-parietal, middle-inferior temporal, insular, precuneus, supramarginal, lateral-occipital and cingulate regions, while subcortical CBF was relatively preserved in aging. Regional effects of age on CBF differed from that of grey-matter atrophy. In addition, the pattern of CBF associations with age displays an interesting similarity with the default-mode network. These findings demonstrate the dissociation between regional CBF and structural alterations specific to normal aging, and augment our understanding of mechanisms of pathology in older adults.
先前的研究已经证明，在正常衰老过程中大脑血流（CBF）会减少，但 CBF 变化的完整空间模式和潜在机制仍有待阐明。具体来说，现有数据在这种变化的空间分布方面并不完全一致，这可能是由于在 CBF 测量中忽略了与年龄相关的组织萎缩的影响。在这项工作中，我们使用脉冲动脉自旋标记来量化 86 名认知和身体均健康的成年人的局部 CBF，年龄在 23 至 88 岁之间。我们利用基于表面的分析来绘制 CBF 和皮质厚度随年龄增长而出现的区域下降图，并检查这些指标之间的空间关联和分离。我们的结果表明，皮质灌注存在与年龄相关的区域性减少，涉及额上回、眶额回、顶下小叶、中下回、脑岛、楔前叶、缘上回、外侧枕叶和扣带回区域，而皮质下 CBF 在衰老过程中相对保持不变。年龄对 CBF 的区域影响与灰质萎缩的影响不同。此外，CBF 与年龄的关联模式与默认模式网络具有有趣的相似性。这些发现表明，正常衰老过程中局部 CBF 与特定的结构改变之间存在分离，并加深了我们对老年人病理学机制的理解。
