Quantifying Spatial Variations of Cardiac-Induced Volumetric Strain Using DENSE MRI: Insight from an Observational Study

Motivation: The heartbeat causes deformations and volumetric strain in the surrounding brain tissue which can be observed using Displacement Encoding with Stimulated Echoes (DENSE) MRI. Local variations in volumetric strain reveal both expansion and compression in individual voxels or regions. Goal(s): To offer insights into the heterogeneous patterns seen in volumetric strain maps. Approach: Volumetric strain data of nine subjects was included and clustered (k-means) into four clusters. Results: Both expanding and compressing clusters were found in all subjects. Compressing clusters were mostly found at the periphery of the brain and possibly reflect structures facilitating fluid movement (sulci and veins). Impact: Clustering volumetric strain data into individual clusters with similar voxels reveals distinct volumetric strain profiles in DENSE data. Potentially, these clusters can be used to cleanup DENSE data from fluid-related artifacts to make the data specifically reflect brain tissue strains.