Quantification of cerebral cortical displacement driven by visual stimulation using motion-encoded stimulated-echo EPI at 7T

Motivation: Tissue motion may mediate the relationship between blood volume and CSF flow dynamics, as functional hyperemia may displace tissue; however, cortical tissue motion in response to neuronal stimulation has not yet been measured dynamically. Goal(s): To demonstrate the feasibility of quantifying stimulation-locked tissue displacement. Approach: We optimized a novel method for concurrent BOLD-fMRI and tissue displacement quantification based on the DENSE technique for activity-related tissue motion, and applied it in vivo with a visual stimulation paradigm. Results: We identified patterns of tissue motion co-occurring with the onset and offset of the visual stimulus and demonstrated that patterns differ between gray matter and CSF. Impact: Cerebral cortical tissue motion in response to neuronal activation is quantified in vivo in real-time, enabling investigations into the contributions of tissue displacement to CSF flow patterns and characterization of dynamic partial volume effects for fMRI analysis and interpretation.