Using water beads as static tissue in a Circle of Willis flow phantom in 4D flow MRI

Motivation: While previous research has focused on realistic vessel and flow replication, the background tissue mimicking in 4D flow MRI remains unexplored despite its significant impact on phase correction accuracy. Goal(s): Aims to identify a suitable material for a Circle of Willis flow phantom that can mimic background static tissue, ensure transparency, and constrain vessel motion. Approach: Transparent water beads soaked in a Gd-doped solution were used as background static tissue in a flow phantom. A MATLAB tool was used for the post-processing of the 4D-flow data. Results: Water beads effectively minimized motion artifacts, and increased the number of time-averaged streamlines and their quality. Impact: This study introduces a practical solution, to enhance the accuracy of in-vitro 4D Flow MRI of complex vessel phantoms by mitigating motion artifacts. The transparent water beads offer a cost-effective and easily exchangeable alternative for mimicking background static tissue.