Quantitative phase-contrast CSF-flow interleaved with cortical BOLD to measure glymphatic function via BOLD-CSF coupling

Motivation: CSF-mediated brain waste clearance is implicated in proteinopathies such as Alzheimer’s disease. A better understanding of clearance mechanics is needed to understand pathological processes. Goal(s): To quantify flow- and pulsatility dynamics of CSF-motion in the 4th-ventricle using real-time phase contrast (rtPC) with interleaved BOLD-imaging while manipulating flow. Approach: rtPC is first interleaved with inflow-sensitized EPI to prove the same CSF-fluctuations are captured. Then, we show BOLD-CSF coupling between rtPC and cortical BOLD as well as between inflow-EPI and cortical BOLD during breathing and visual-stimulation paradigms. Results: rtPC improves characterization of CSF-flow in the 4th-ventricle compared to traditional BOLD-sequences, showing more coherent BOLD-CSF coupling. Impact: Clinical MR studies are increasingly looking at changes in BOLD-CSF coupling in patient populations as a measure of brain clearance efficiency. By interleaving phase contrast acquisitions with BOLD, we quantify CSF flow dynamics and obtain more robust BOLD-CSF measurements.