Motivation: Gradient-echo (GE) BOLD-fMRI has been used with vasodilation to measure the cerebrovascular reactivity (CVR). However, the GE-BOLD signal is weighted by cerebral blood volume (CBV) in large veins. Spin-Echo (SE) BOLD fMRI is less sensitive to large veins and may deliver estimates closer to the physiological CVR. Goal(s): To compare GE-BOLD, SE-BOLD, and CBF based CVR measurements across subjects and across space. Approach: Concurrent GE/SE BOLD-ASL acquisitions were performed during breath-holding (BH). We computed the CVR maps for the three signals. Results: The grey matter (GM) SE-BOLD CVR correlated more highly than GE-BOLD CVR with the ASL-derived GM CBF-CVR, across subjects and space. Impact: SE BOLD-fMRI may deliver a marker of CVR that resembles the physiological (CBF) CVR more closely than CVR based on GE BOLD, with the advantage of high signal-to-noise ratio compared to ASL.
Pomante et al. (Tue,) studied this question.