4D-Flow imaging of perivascular CSF and blood flow coupling using an ultra-high performance head-only system

Motivation: Perivascular cerebrospinal fluid (CSF) flow contributes to brain waste clearance but is poorly understood. While animal studies suggest arterial pulsatility drives perivascular CSF motion in the blood flow direction, human MRI studies have typically relied on non-quantitative approaches that do not inform on flow-directionality. Goal(s): Evaluate blood-CSF coupling in the proximity of major cerebral arteries. Approach: High-resolution 4D flow MRI using an ultra high-performance head-only system in volunteers (N=3) at Venc=5-10mm/s (CSF) and Venc=800mm/s (blood). Results: Coupled blood-CSF motion was observed along the middle cerebral artery (MCA). Most segments showed an inverse and synchronous coupling-relation, i.e., blood/CSF flow pulsations in opposite directions. Impact: The current approach shows that 4D flow imaging of very slow CSF motion is feasible using high-performance head-only systems. The proposed method and our preliminary data could benefit our current understanding of human blood-CSF flow relationships and neurofluid flow dynamics.