Contactless Cardiac Triggering Using Camera PPG in Cardiac MR

Motivation: Contactless cardiac triggering makes cardiac and cardiovascular MRI (cMRI) more accessible by improving patient comfort, reducing complexity, facilitating swift workflow, and increasing patient throughput. Goal(s): In this work we demonstrate feasibility of contactless cardiac trigger detection using an in-bore camera in two routine cMRI sequences. Approach: Building on an existing in-bore camera hardware we developed a cardiac trigger detection method for cMRI that extracts a remote photoplethysmography (rPPG) signal acquired at the patient’s forehead. The quality of the acquired MR images is compared with ECG triggering. Results: rPPG and ECG triggering delivered comparable image quality in the majority of study volunteers. Impact: The presented work provides evidence that cMRI is feasible with contactless, camera-based cardiac signal detection. The proposed method allows cMRI without placement of ECG electrodes, thus increasing accessibility of cardiac MR.