Vessel‐encoded arterial spin labeling (VE‐ASL) reveals elevated flow territory asymmetry in older adults with substandard verbal memory performance

Purpose To evaluate how flow territory asymmetry and/or the distribution of blood through collateral pathways may adversely affect the brain's ability to respond to age‐related changes in brain function. These patterns have been investigated in cerebrovascular disease; however, here we evaluated how flow‐territory asymmetry related to memory generally in older adults. Materials and Methods A multi‐faceted MRI protocol, including vessel‐encoded arterial spin labeling capable of flow territory mapping, was applied to assess how flow territory asymmetry; memory performance (CERAD‐Immediate Recall); cortical cerebral blood flow (CBF), white matter lesion (WML) count, and cortical gray matter volume were related in older healthy control volunteers (HC; n = 15; age = 64.5 ± 7 years) and age‐matched mild cognitive impairment volunteers (MCI; n = 7; age = 62.7 ± 3.7 years). Results An inverse relationship was found between memory performance and flow territory asymmetry in HC volunteers ( P  = 0.04), which reversed in MCI volunteers ( P  = 0.04). No relationship was found between memory performance and cortical tissue volume in either group ( P  > 0.05). Group‐level differences for HC volunteers performing above versus below average on CERAD‐I were observed for flow territory asymmetry ( P  < 0.02) and cortical volume ( P  < 0.05) only. Conclusion Findings suggest that flow territory asymmetry may correlate more sensitively with memory performance than CBF, atrophy and WML count in older adults. J. Magn. Reson. Imaging 2014;39:377–386 . © 2013 Wiley Periodicals, Inc .