Isolating the arterial blood volume change to probe fMRI spatial specificity

BOLD fMRI is widely used in neuroscience, but has limited spatial specificity while alternative approaches based on tissue cerebral blood volume (CBV) change have limited sensitivity. Recently, arterial CBV change (Arterial Blood Contrast; tracked through magnetization-transfer) was suggested as an fMRI mechanism, but its localization and sensitivity remain unexplored, since efficiently isolating the arterial CBV is challenging. Here, we combine temporally-efficient saturation with center-slice-out readouts and BOLD-correction to isolate arterial CBV for high-resolution 7T human fMRI. Our novel sequence shows much-improved specificity compared to BOLD and similar sensitivity to VASO, suggesting Arterial Blood Contrast to be a promising fMRI approach.