132 Chapter 6 ABSTRACT Introduction The role of cerebral blood flow (CBF) in the early stages of Alzheimer’s disease is complex and largely unknown. We investigated cross-sectional and longitudinal associations between CBF, amyloid burden and cognition, in cognitively normal individuals. Methods We included 187 cognitively normal individuals from the SCIENCe project. Each underwent a dynamic [18F]florbetapir PET enabling calculation of mean binding potential (BPND) and R1 (measure of relative (r)CBF). Eighty-three individuals underwent a second [18F]florbetapir PET. Participants annually underwent neuropsychological assessment. Results At baseline, a low R1 and high BPND were independently associated with cognitive decline. A high baseline BPND predicted a decline over time in R1 and vice versa, a low baseline R1 predicted an increase in BPND. Discussion Our results suggest that amyloid accumulation and decrease in rCBF are two parallel disease processes without a fixed order, both providing unique predictive information for cognitive decline and each enhancing the other longitudinally.