Full Free-Breathing Cardiac MRI: Enhancing Efficiency and Image Quality in Clinical Practice

Conventional cardiac magnetic resonance (CMR) examinations require patients to repeatedly hold their breath, which can reduce examination efficiency and pose challenges for patients unable to do so. This study aimed to demonstrate the feasibility and effectiveness of a full free-breathing CMR protocol in clinical practice. Patients prospectively enrolled in this study underwent a full free-breathing CMR exam on a 3T scanner between June 1 and June 30, 2024. Acquisition time and image quality were assessed. Cine and flow imaging were compared with those acquired with the conventional breath-holding CMR protocol. Other sequences, including T1/T2 mapping and late gadolinium enhancement (LGE), were evaluated quantitatively and qualitatively, respectively. Group comparisons were performed using the Wilcoxon signed-rank test or paired t-test. Consistency was assessed using Kappa statistics, Bland-Altman statistics, intraclass correlation coefficient (ICC) and linear regression. A total of 211 patients were evaluated (median age: 53 years [IQR: 38-63]; range: 10-82 years; 145 men). The mean acquisition time for full free-breathing CMR was 22.6±3.7min. The median image quality scores for cine and LGE images acquired with free-breathing CMR were 4 (IQR: 4-4) and 5 (IQR: 4-5), respectively. Compared with conventional breath-holding CMR, the end-diastolic volume (EDV), end-systolic volume (ESV), EDV index and ESV index measured by free-breathing CMR were slightly higher (all P＜0.05), whereas the left ventricular ejection fraction (LVEF) and left ventricular mass (LVM) were slightly lower (both P＜0.05). Nonetheless, the two methods demonstrated good agreement and correlation (r values: 0.85-0.99). Native T1 and T2 values in healthy subjects from free-breathing CMR were 1214.9±16.7ms and 38.4±3.2ms, respectively. Among the 211 patients, 147 were LGE positive. Except for five patients with image quality scores below 3, all others had scores of 3 or higher. Full free-breathing CMR examinations are feasible and effective in clinical practice, significantly reduce scan time while maintaining high image quality.