Real-time Respiratory Correction of the Pilot Tone Cardiac Signal to Stabilize Triggering during Breath-holds

Motivation: This research aims to refine Pilot Tone (PT) cardiac triggering, which can be impacted by changes in signal amplitude caused by breath-holding. Goal(s): Its primary goal is to develop and validate a real-time correction algorithm that improves the PT cardiac trigger stability during breath-holds without introducing additional variability during free breathing. Approach: The algorithm analyzes PT data for respiratory patterns to adapt beat-by-beat amplitude correction of the cardiac signal. The methodology was tested with different breathing paradigms at 1.5T and 3T to assess robustness. Results: The correction successfully adjusted PT cardiac signal amplitude, reducing missed triggers across respiratory patterns without increasing triggering variation. Impact: The described real-time correction improves the reliability of cardiac PT triggers during inspiratory breath-hold maneuvers, increasing the opportunities to replace ECG triggering with PT triggering, and therefore to eliminate the need for ECG leads.