Sensitive structural and functional measurements and 1-year pulmonary outcomes in pediatric cystic fibrosis.

BACKGROUND

Two functional measurements (multiple breath washout [MBW] and hyperpolarized Xe ventilation magnetic resonance imaging [Xe MRI]) have been shown to be more sensitive to cystic fibrosis (CF) lung obstruction than traditional spirometry. However, functional techniques may be sensitive to different underlying structural abnormalities. The purpose of this study was to determine relationships between these functional markers, their pathophysiology, and 1-year clinical outcomes.

METHODS

Spirometry, MBW, Xe MRI, and ultrashort echo-time (UTE) MRI were obtained in a same-day assessment of 27 pediatric CF patients (ages 11.5±5.0) who had not begun CFTR modulator therapies. UTE MRI was scored for structural abnormalities and functional metrics obtained via spirometry, MBW and Xe MRI. 1-year outcomes (ΔFEV and pulmonary exacerbations), during which ≈50% initiated modulator therapy, were obtained from the electronic medical record.

RESULTS

MBW, Xe MRI, and UTE MRI detected clinically significant disease in more subjects (>78%) compared to spirometry (<30%). UTE MRI suggests increased odds of bronchial changes when mucus plugging is present in the same lobe. MBW and Xe MRI correlated best with mucus plugging, while spirometry correlated best with consolidations. Bronchial abnormalities were associated with future pulmonary exacerbations.

CONCLUSIONS

MBW, Xe MRI, and UTE MRI are more sensitive for detection of pediatric CF lung disease when compared to spirometry. MBW and Xe MRI correlated with structural abnormalities which occur in early CF disease, suggesting MBW and Xe MRI are valuable tools in mild CF lung disease that can guide clinical decision making.