Structure and function imaging in primary ciliary dyskinesia: cross-sectional study with 129Xe ventilation/1H anatomical magnetic resonance imaging

Background In primary ciliary dyskinesia (PCD), impaired mucociliary clearance leads to respiratory infections. Whilst forced expiratory volume in 1 s (FEV 1 ) is commonly used to evaluate lung function in PCD its sensitivity to detect abnormalities in mild disease is limited. This study explores the utility of 129 Xe ventilation and 1 H anatomical magnetic resonance imaging (MRI) to assess lung health in children with PCD. Methods This prospective cohort study assessed clinically stable children with PCD (aged 5–18 years) using 129 Xe MRI, 1 H MRI and spirometry during one session. Ventilation defect percentage (VDP) was the primary metric calculated from 129 Xe MRI. Results 35 children were assessed (mean± sd age 12.3±3.3 years, FEV 1 z-score −1.5±1.7). Most children had visible ventilation abnormalities and 82.8% had an abnormal 129 Xe VDP (median (interquartile range) 129 Xe VDP 6.3% (1.3–16.1%)). 16 participants had a normal FEV 1 (z-score > −1.6); however, 12 of these individuals had abnormal 129 Xe VDP. 1 H MRI found 55.9% participants had a region of collapse, 61.3% had bronchiectasis and 50.0% had evidence of air trapping. Conclusions 129 Xe MRI can identify early lung function abnormalities in children with PCD and demonstrates that the extent of ventilation distribution abnormalities in PCD varies between individuals. 1 H MRI provides complementary diagnostic information on structural abnormalities.