129Xe and free-breathing 1H ventilation MRI in patients with cystic fibrosis: a dual-center study

Background

Free-breathing 1H 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 129Xe and 1H 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 129Xe ventilation and 1H 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 129Xe VDP, 1H VDP, FEV1, and LCI. Bland–Altman analysis of 129Xe VDP and 1H VDP was carried out. Differences in metrics were assessed using one-way ANOVA or Kruskal–Wallis tests.

Results

129Xe VDP and 1H VDP correlated strongly with; each other (r = 0.84), FEV1 z-score (129Xe VDP r = −0.83, 1H VDP r = −0.80), and LCI (129Xe VDP r = 0.91, 1H VDP r = 0.82). Bland–Altman analysis of 129Xe VDP and 1H 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 129Xe and 1H VDP (P = 0.08), while 129Xe VDP had a stronger relationship with LCI than 1H VDP.

Data Conclusion

1H ventilation MRI shows large-scale agreement with 129Xe 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