Cardiac MR Gating Using a Non-contact MR-compatible Doppler Radar System at 3T: Initial Results on Healthy Subjects

Motivation: Conventional electrocardiography (ECG) multi-electrode setups are essential for cardiac MR (CMR) gating, but they are cumbersome and pose electrical safety risks to patients. Goal(s): This study aims to investigate a feasible non-contact CMR gating approach using a MR-compatible doppler cardiac radar, and it can possibly offer improved patient comfort and flexibility. Approach: An 886 MHz microstrip-patch-based MR-compatible cardiac radar was proposed, optimized, and fabricated, and it worked with a home-made FPGA module to communicate with the scanner to achieve real-time cardiac triggering. Results: In-vivo scans validated the feasibility of the proposed approach, which was rigorously compared with CMR images via traditional ECG methods. Impact: The proposed cardiac radar provides a non-contact alternative for cardiac gating in MRI. Future research may explore signal biological mechanisms and its additional applications in respiratory gating.