ASL-derived cerebrovascular brain-age improves associations with cognitive decline

Motivation: Structural brain ageing models are associated with cognitive decline, and the addition of arterial spin labelling (ASL)-derived improved brain-age estimation accuracy, but the relation between cerebrovascular ageing and cognitive decline is not yet fully understood. Goal(s): To assess the contribution of ASL in the relationship between brain-age estimates and cognitive decline. Approach: Brain-age estimation accuracy and linear relationships with composite cognitive scores were compared between structural-only (T1w and FLAIR), ASL-only, and structural+ASL models. Results: Combined structural and ASL brain-age models showed the highest accuracy and increased effect sizes with composite cognitive scores, however, ASL-only models showed unexpected relationships. Impact: Combined structural-ASL brain-age models might present a surrogate biomarker in an earlier stage of cognitive decline, aiding in diagnosis and treatment monitoring. Possible mediation effects of ASL on the association of structural decline with cognitive domains should be investigated further.