A Physiologic Left Ventricle Flow Phantom for 4D Flow MRI Applications and CFD Verification

In vivo verification for the development of cardiac MRI and CFD simulations is limited by scan time and motion artifacts. We developed a subject-specific, MRI-compatible left ventricle (LV) phantom within a closed-loop circulation system driven by an MRI-safe pump to reproduce cardiac motion and provide robust data for high-fidelity model validation.

The LV was fabricated from a PVA-based hydrogel to ensure MRI contrast, mechanical stability, and reusability. The complete setup fulfills key requirements for long-term leakage-free operation, close coil placement, and resembles in vivo soft-tissue contrasts. The setup reproduces healthy end-diastolic and end-systolic geometries, including physiologic contraction and papillary muscles. Integrated aortic and mitral valves approximate physiological opening and closing. High image contrast enabled time-resolved segmentation of the LV geometry.

The LV shape matched the target anatomy well, despite minor deviations at the basal transition and in valve orifice, with mild aortic stenosis and mitral regurgitation. 4D flow MRI confirmed physiological flow patterns, including diastolic vortex ring formation and realistic systolic outflow. Velocity estimates confirmed the phantom's applicability in an in vitro setting without scan time limitations. The acquired time-resolved MRI data enabled CFD simulations incorporating LV and valve motion, although segmentation accuracy remains a primary source of uncertainty.

This LV phantom provides a stable, MRI-compatible platform for generating reproducible data to validate modeling of intracardiac hemodynamics. Its realistic anatomy, motion, and flow patterns support both simulation validation and MRI sequence development. Future work will focus on improving valve kinematics and LV motion fidelity.