Cerebrovascular Reactivity to CO2 Differences in Aging Adults Identified by a Coherence Weighted Frequency-Domain Analysis of BOLD MRI

Motivation: Maps of cerebrovascular reactivity (CVR) to CO2 facilitates detection of cerebrovascular disease and assess stroke risk, but the cumbersome acquisition and analysis of synchronized imaging and physiological data limits their use in large studies. Goal(s): Demonstrate a Blood Oxygen-Level Dependent (BOLD) and end-tidal CO2 (ETCO2) acquisition and analytical approach suitable for mapping CVR in a large study. Approach: We acquired and analyzed BOLD and ETCO2 changes during breathing tasks in 53 aging adults and calculated BOLD-CVR to CO2 with a frequency-domain coherence-weighting. Results: During breathing tasks, female versus male participants showed an age-dependent increase in BOLD-CVR to CO2. Impact: More accessible BOLD and ETCO2 acquisition and analysis techniques using mild breathing tasks can lead to more widespread use of BOLD-CVR to CO2 in a variety of populations and might facilitate more widespread characterization of cerebrovascular health and risk factors.