Imaging glymphatic flow: Initial results using inversion-prepped gradient recalled echo (GRE) diffusion imaging

Motivation: The glymphatic system may play a central role in neurodegenerative disease, but noninvasive, in vivo imaging is limited. Goal(s): To develop a novel pulse sequence to selectively measure cerebrospinal fluid (CSF) in the glymphatic system. Approach: A conventional spin echo diffusion acquisition was modified to use a GRE, suppressing white matter (WM), relative to CSF, due to T2* weighting. Inversion recovery preparation further suppressed WM. Results: With suppression of WM, remaining signal is consistent with movement of CSF along perivascular spaces (PVS), which are associated with the glymphatic system. Quantitative assessment indicates enhanced diffusion along PVS and of the DTI-ALPS index. Impact: We present a new approach to image the glymphatic system. With further development, early detection and evaluation of intervention strategies for a broad range of neurodegenerative diseases may become possible.