Age-associated reductions in cerebral blood flow are independent from regional atrophy

• Published in: NeuroImage (Orlando, Fla.) Vol. 55; no. 2; pp. 468 - 478
• Main Authors: Chen, J. Jean, Rosas, H. Diana, Salat, David H.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15.03.2011; Elsevier Limited
• Subjects: Adult; Age; Aged; Aged, 80 and over; Aging; Aging - pathology; Aging - physiology; Alzheimer's disease; Arterial-spin labelling (ASL); Atrophy - pathology; Blood; Brain - blood supply; Brain - pathology; Cerebral blood flow (CBF); Cerebral cortex; Cerebrovascular Circulation - physiology; Cortical thickness; Dementia; Diabetes; Female; Humans; Hypertension; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Magnetic resonance imaging (MRI); Male; Medical imaging; Middle Aged; Older people; Quantitative perfusion; Young Adult; Cerebral cortex; Cortical thickness; Quantitative perfusion; Aging; Magnetic resonance imaging (MRI); Arterial-spin labelling (ASL); Cerebral blood flow (CBF); Alzheimer's disease; Dementia
• ISSN: 1053-8119; 1095-9572; 1095-9572
• DOI: 10.1016/j.neuroimage.2010.12.032

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 88years. 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. ► First study to map quantitative CBF in normal aging using pulsed arterial-spin labelling. ► First study to probe spatial link between CBF and atrophy in normal aging using surface-based analysis. ► Grey matter CBF was regional reduced in aging primarily in the cortex. ► CBF reductions were not strongly associated with grey-matter atrophy. ► Perfusion and structural imaging provide distinct pictures of neuronal health.