Accuracy, repeatability, and sensitivity of breath-hold calibrated fMRI for the mapping of absolute CMRO2

Motivation: Gas-calibrated fMRI provides a sensitive measurement of cerebral oxygen consumption, but its applicability is limited to young, healthy participants who can tolerate the gas challenges. Goal(s): Our goal was to establish the feasibility of breath-hold calibrated fMRI (bhc-fMRI) to replace gas challenges. Approach: We compared bhc-fMRI to a global oxygen extraction fraction (OEF) measurement, measured within session repeatability and tested the sensitivity of the method to a visual stimulus. Results: We found similar agreement to global OEF measurements as for gas-calibrated fMRI and moderate within session repeatability. Robust responses to continuous visual stimulation of CBF/CMRO2/OEF (+15%/+11%/-3%) demonstrate good sensitivity of the bhc-fMRI method. Impact: We establish breath-hold calibrated fMRI as a viable alternative to gas-calibrated fMRI for mapping cerebral oxygen consumption. Breath-hold calibrated fMRI is simple to implement and is tolerable for ageing cohorts and patients with neurodegenerative pathologies.