Functional MRI with UTE to investigate stimulus-driven CSF flow

Motivation: Dynamics of CSF-flow has been shown to relate to whole-cortex BOLD signals during intense stimulation, but the relationship with blood-flow is not known. Goal(s): Determine the correspondence of flow-mediated UTE-fMRI signals in whole-cortex and CSF. Approach: UTE-fMRI and BOLD-EPI were performed at 7T on 12 humans. Correlations between time-courses were calculated in atlas-based regions. Results: We detected anticorrelated task-evoked UTE signal changes in whole-cortex and CSF. On the other hand, BOLD signals in whole-cortex correlated with those in CSF, with no clear task-evoked signal changes seen in these regions during stimulation. Impact: Since UTE-fMRI signals are mediated by flow dynamics, they enable determining the relationship between blood-flow and CSF-flow more directly than BOLD. This opportunity is critical for understanding how the brain ensures global homeostasis during the demands of regional activity.