Free‐Breathing Dynamic, Regularized, Adaptive Cluster Optimization ( <scp>DRACO</scp> ) Cine Cardiac <scp>MRI</scp> in Atrial Fibrillation

ABSTRACT Background Existing strategies for free‐breathing cine cardiac MR, including real‐time imaging, struggle with complex arrhythmias such as atrial fibrillation (AF). Dynamic regularized adaptive clustering optimization (DRACO) has been proposed to generate high‐quality and quantifiable breath‐held cine images for patients in AF. Purpose To tailor DRACO for free‐breathing and evaluate its potential to simultaneously handle cardiac and respiratory motion. Study Type Prospective. Subjects 10 sinus rhythm (10 males), 20 AF (18 males). Field Strength/Sequence 3.0 T, balanced steady‐state free precession (bSSFP) with sorted golden‐step, ECG‐gated segmented cine, and real‐time. Assessment Patients were imaged using the golden‐step sequence under breath‐held and free‐breathing conditions, and the reference bSSFP cine sequence. Signal‐to‐noise ratio (SNR), contrast‐to‐noise ratio (CNR), edge sharpness, and image quality (4‐point Likert scale) were assessed. Statistical Tests Paired t ‐test, Friedman test, regression analysis, Fleiss' Kappa. Significance level p < 0.05. Results The SNR and CNR values of DRACO images showed no significant differences between breath‐held and free‐breathing conditions in both sinus rhythm (SNR p = 0.53; CNR p = 0.87) and in AF (SNR p = 0.56; CNR p = 0.55). Image sharpness was not significantly different between breath‐held and free‐breathing in both sinus rhythm ( p = 0.24) and AF ( p = 0.79). In AF patients, breath‐held DRACO and free‐breathing DRACO had significantly higher image quality scores than real‐time cine. In sinus rhythm patients, there was no significant difference ( p = 0.13) between breath‐held or free‐breathing DRACO and segmented cine. Despite significant within‐patient ejection fraction (EF) differences between breath‐held versus free‐breathing in 80% of sinus rhythm and 70% of AF patients, the average EF between breath‐held versus free‐breathing DRACO showed high correlation (sinus rhythm R 2 = 0.71; AF R 2 = 0.71), demonstrating DRACO's robustness to motion variation. Data Conclusion DRACO is robust to respiratory motion and AF‐related irregular cardiac motion. It enables high‐quality cine image generation in both regular and irregular cardiac motion, with or without breath holding. Level of Evidence 1. Technical Efficacy Stage 2.