Assessing cerebral microvascular pulsatility using dynamic pseudo-continuous arterial spin labeling MRI

Motivation: Directly imaging cerebral microvascular pulsation remains challenging, which, however, plays an important role in glymphatic function to facilitate waste clearance in perivascular space. Goal(s): To develop a dynamic pCASL method for measuring the cerebral microvascular pulsatility index (PI). Approach: Dynamic pCASL imaging is implemented to image blood flow in cerebral arterioles. Resulting ASL signals were retrospectively synchronized with heartbeat to resolve ASL signal pulsations across cardiac cycle. Numerical simulations were conducted to investigate the confounding effects on ASL signals including labeling efficiency and ATT due to heartbeat. Results: Our results demonstrated the feasibility and reliability of proposed approach in measuring the microvascular PI. Impact: We proposed a non-invasive MRI technique to reliably measure cerebral microvascular pulsatility, which fills a significant research gap in research related to brain waste clearance.