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

Background In Primary ciliary dyskinesia (PCD), impaired mucociliary clearance leads to respiratory infections. Whilst 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. Methodology 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 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 (IQR) 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; 58.1% had bronchiectasis; and 50.0% had evidence of air trapping. Conclusion 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.