Evaluation of high-amplitude pilot-tone with interference cancellation (HAPTIC) cardiac gating at 0.55T in the challenging case of arrhythmia

Motivation: Cardiac gating at 0.55T with pilot tone has been elusive because the pilot tone signal scales with B0 field strength, and cardiac motion is a weak modulation. High-amplitude pilot tone with interference cancellation (HAPTIC) addresses this issue, but has not yet been tested in challenging cases. Goal(s): To evaluate HAPTIC cardiac gating at 0.55T in the challenging case of cardiac arrhythmia. Approach: Four subjects with cardiac arrhythmia were scanned, and HAPTIC was compared against ECG recordings. Detected R-wave jitter and false positive/negative rates are reported. Results: Cardiac motion extraction for arrhythmia patients at 0.55T using HAPTIC is possible, and we identify failure cases. Impact: HAPTIC could potentially replace ECG gating, even in patients with cardiac arrhythmia. This would simplify clinical workflow and serve scanners that do not have an integrated ECG.