Dual-Center Repeatability, Consistency, and Comparison of 3D Phase-Resolved Functional (PREFUL) Ventilation MRI at 3 and 1.5 T in Healthy Volunteers.

3D phase-resolved functional lung (PREFUL) MRI offers lung ventilation assessment without contrast and in free breathing. However, there are limited data on its repeatability and intercenter consistency. This study aimed to assess the repeatability and intercenter consistency of 3D PREFUL MRI at two centers using both 3- and 1.5-T field strengths. Fifty healthy volunteers (35 female, 70%; median age 25.5 [interquartile range 22.3-29.0 years]) participated in this prospective study. A golden-angle stack-of-stars spoiled gradient echo acquisition was used for 3D PREFUL MRI. To assess for repeatability, 3D PREFUL MRI was performed twice with a short interval between scans at each center. At Center 1, scans were performed at 3 and 1.5 T. At Center 2, scans were performed at 3 T. Intercenter consistency of 3D PREFUL MRI was assessed between centers at 3 T. Performance of 3D PREFUL MRI at 3 and 1.5 T was compared at Center 1. Bland-Altman analysis, coefficient of variation, intraclass correlation coefficient, and Cohen's d were used for the repeatability assessment. Similarly, interfield strength and intercenter differences were quantified by Bland-Altman analysis. In all comparisons, paired Wilcoxon signed-rank test was used to examine differences. 3D PREFUL MRI parameters showed no significant differences between repeated measurements across three scanners, except for mean regional ventilation (RVent) at Center 2 (p = 0.0046). Apart from mean RVent during the second measurement (p = 0.03) and tidal volume during both measurements (both p < 0.02), no significant differences were found between 3D PREFUL MRI parameters at 3 T across both centers. Output parameters were significantly different when images were acquired using 3 T compared to 1.5 T (all p < 0.0093). 3D PREFUL MRI ventilation-weighted parameters showed fair to excellent repeatability and consistent intercenter results. Given the significant differences in outputs acquired using scanners of different field strengths, multicenter studies should be conducted with scanners of the same field strength.