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

Science and Research

BACKGROUND: Free-breathing (1) H 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 (129) Xe and (1) H 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 (129) Xe ventilation and (1) H 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 (129) Xe VDP, (1) H VDP, FEV(1) , and LCI. Bland-Altman analysis of (129) Xe VDP and (1) H VDP was carried out. Differences in metrics were assessed using one-way ANOVA or Kruskal-Wallis tests. RESULTS: (129) Xe VDP and (1) H VDP correlated strongly with; each other (r = 0.84), FEV(1) z-score ((129) Xe VDP r = -0.83, (1) H VDP r = -0.80), and LCI ((129) Xe VDP r = 0.91, (1) H VDP r = 0.82). Bland-Altman analysis of (129) Xe VDP and (1) H 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 FEV(1) were not significantly different between (129) Xe and (1) H VDP (P = 0.08), while (129) Xe VDP had a stronger relationship with LCI than (1) H VDP. DATA CONCLUSION: (1) H ventilation MRI shows large-scale agreement with (129) Xe 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.