Assessment of the macrovascular contribution to resting-state fMRI functional connectivity at 3 Tesla

Motivation: Resting-state fMRI (rs-fMRI) based functional connectivity (fcMRI) is widely used to image neuronal networks, but it could be biased by the contribution of macrovasculature. Goal(s): This study aims to provide a better understanding of vascular rs-fMRI contributions and their interpretation. Approach: Our study evaluated macrovascular contributions to experimental rs-fcMRI data. Results: We found both arteries and veins to substantially modulate fcMRI metrics. We also found that vascular-driven fcMRI spatial variance was disproportionately high given the low vascular voxel count. In particular, veins contribute more to connectivity strength than arteries, while arteries contribute more to spatial variance than veins. Impact: The macrovasculature was previously shown to modulate functional connectivity and reduce its neuronal specificity, but a systematic analysis is still lacking. This study demonstrates macrovascular contributions at 3 Tesla and paves the way for the correction of bias in rs-fMRI.