129Xe and Free-Breathing 1H Ventilation MRI in Patients With Cystic Fibrosis: A Dual-Center Study

Background Free-breathing H-1 ventilation MRI shows promise but only single-center validation has yet been performed against methods which directly image lung ventilation in patients with cystic fibrosis (CF). Purpose To investigate the relationship between Xe-129 and H-1 ventilation images using data acquired at two centers. Study type Sequence comparison. Population Center 1; 24 patients with CF (12 female) aged 9-47 years. Center 2; 7 patients with CF (6 female) aged 13-18 years, and 6 healthy controls (6 female) aged 21-31 years. Data were acquired in different patients at each center. Field Strength/Sequence 1.5 T, 3D steady-state free precession and 2D spoiled gradient echo. Assessment Subjects were scanned with Xe-129 ventilation and H-1 free-breathing MRI and performed pulmonary function tests. Ventilation defect percent (VDP) was calculated using linear binning and images were visually assessed by H.M., L.J.S., and G.J.C. (10, 5, and 8 years' experience). Statistical Tests Correlations and linear regression analyses were performed between Xe-129 VDP, H-1 VDP, FEV1, and LCI. Bland-Altman analysis of Xe-129 VDP and H-1 VDP was carried out. Differences in metrics were assessed using one-way ANOVA or Kruskal-Wallis tests. Results Xe-129 VDP and H-1 VDP correlated strongly with; each other (r = 0.84), FEV1 z-score (Xe-129 VDP r = -0.83, H-1 VDP r = -0.80), and LCI (Xe-129 VDP r = 0.91, H-1 VDP r = 0.82). Bland-Altman analysis of Xe-129 VDP and H-1 VDP from both centers had a bias of 0.07% and limits of agreement of -16.1% and 16.2%. Linear regression relationships of VDP with FEV1 were not significantly different between Xe-129 and H-1 VDP (P = 0.08), while Xe-129 VDP had a stronger relationship with LCI than H-1 VDP. Data Conclusion H-1 ventilation MRI shows large-scale agreement with Xe-129 ventilation MRI in CF patients with established lung disease but may be less sensitive to subtle ventilation changes in patients with early-stage lung disease. Evidence Level 2 Technical Efficacy Stage 2