Monitoring pulsatile CSF motion in the subarachnoid space using MRI

Motivation: The characterization of pulsatile cerebrospinal fluid (CSF) flow within the subarachnoid space remains insufficiently understood, presenting a challenge in distinguishing CSF flow from blood flow. Goal(s): Our goal was to develop a time-efficient approach to monitor pulsatile CSF motion, independent of the pulsatile blood signal. Approach: We introduced a cardiac-gated BOLD sequence with flow-sensitive bipolar gradients to characterize CSF motion, and evaluated blood contamination using cardiac-gated arterial-spin-labeling. Results: We demonstrated that the main cause of the signal fluctuation is pulsatile CSF. The fluctuation patterns could be characterized by two components (hump and trough), which were consistently observe across subjects. Impact: The pulsatile CSF motion in the subarachnoid space can now be efficiently monitored with our method. This technique complements the ventricular CSF motion methods and together they may provide a better understanding of CSF and glymphatic circulation in the brain.