RT Journal Article SR Electronic T1 Temporal and Spatial Variances in Arterial Spin-Labeling Are Inversely Related to Large-Artery Blood Velocity JF American Journal of Neuroradiology JO Am. J. Neuroradiol. FD American Society of Neuroradiology DO 10.3174/ajnr.A5257 A1 A.D. Robertson A1 G. Matta A1 V.S. Basile A1 S.E. Black A1 C.K. Macgowan A1 J.A. Detre A1 B.J. MacIntosh YR 2017 UL http://www.ajnr.org/content/early/2017/06/15/ajnr.A5257.abstract AB BACKGROUND AND PURPOSE: The relationship between extracranial large-artery characteristics and arterial spin-labeling MR imaging may influence the quality of arterial spin-labeling–CBF images for older adults with and without vascular pathology. We hypothesized that extracranial arterial blood velocity can explain between-person differences in arterial spin-labeling data systematically across clinical populations.MATERIALS AND METHODS: We performed consecutive pseudocontinuous arterial spin-labeling and phase-contrast MR imaging on 82 individuals (20 – 88 years of age, 50% women), including healthy young adults, healthy older adults, and older adults with cerebral small vessel disease or chronic stroke infarcts. We examined associations between extracranial phase-contrast hemodynamics and intracranial arterial spin-labeling characteristics, which were defined by labeling efficiency, temporal signal-to-noise ratio, and spatial coefficient of variation.RESULTS: Large-artery blood velocity was inversely associated with labeling efficiency (P = .007), temporal SNR (P < .001), and spatial coefficient of variation (P = .05) of arterial spin-labeling, after accounting for age, sex, and group. Correction for labeling efficiency on an individual basis led to additional group differences in GM-CBF compared to correction using a constant labeling efficiency.CONCLUSIONS: Between-subject arterial spin-labeling variance was partially explained by extracranial velocity but not cross-sectional area. Choosing arterial spin-labeling timing parameters with on-line knowledge of blood velocity may improve CBF quantification.AbbreviationsASLarterial spin-labelingCoVcoefficient of variationPCphase contrastWMHwhite matter hyperintensities