Hyperpolarized 129Xe for investigation of mild cystic fibrosis lung disease in pediatric patients

Background: Cystic fibrosis (CF) is a genetic disease which carries high morbidity and mortality from lung-function decline. Monitoring disease progression and treatment response in young patients is desirable, but serial imaging via CT is often considered prohibitive, and detailed functional information cannot be obtained using conventional imaging techniques. Hyperpolarized Xe-129 magnetic resonance imaging (MRI) can depict and quantify regional ventilation, but has not been investigated in pediatrics. We hypothesized that Xe-129 MRI is feasible and would demonstrate ventilation defects in mild CF lung disease with greater sensitivity than FEV1. Methods: 11 healthy controls (age 6-16 years) and 11 patients with mild CF (age 8-16 years, Forced Expiratory Volume (FEV1) percent predicted >70%) were recruited for this study. Nine CF patients had an FEV1 >85%. Each subject was imaged via hyperpolarized Xe-129 MRI, and the ventilation defect percentage (VDP) was measured. FEV1 and VDP were compared between the groups. Results: FEV1 for controls was 100.3% +/- 8.5% (mean +/- sd) and for CF patients was 97.9% +/- 16.0% (p = 0.67). VDP was 6.4% +/- 2.8% for controls and 18.3% +/- 8.6% for CF (p < 0.001). When considering the 9 CF patients with normal FEV1 (>85%), the mean FEV1 was 103.1% +/- 12.3% (p = 0.57 compared to controls) and VDP was 15.4% +/- 6.3% (p = 0.002). Conclusions: Hyperpolarized Xe-129 MRI demonstrated ventilation defects in CF patients with normal FEV1 and more effectively discriminated CF from controls than FEV1. Thus Xe-129 may be a useful outcome measure to detect mild CF lung disease, to investigate regional lung function in pediatric lung diseases, and to follow disease progression. (C) 2016 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.