Detection of early subclinical lung disease in children with cystic fibrosis by lung ventilation imaging with hyperpolarised gas MRI

lung disease in children with cystic fibrosis by lung ventilation imaging with hyperpolarised gas MRI ABSTRACT Hyperpolarised He ventilationMRI, anatomical lung MRI, lung clearance index (LCI), low-dose CT and spirometry were performed on 19 children (6–16 years) with clinically stable mild cystic fibrosis (CF) (FEV1> −1.96), and 10 controls. All controls had normal spirometry, MRI and LCI. VentilationMRI was the most sensitive method of detecting abnormalities, present in 89% of patients with CF, compared with CT abnormalities in 68%, LCI 47% and conventional MRI 22%. Ventilation defects were present in the absence of CT abnormalities and in patients with normal physiology, including LCI. Ventilation-MRI is thus feasible in young children, highly sensitive and provides additional information about lung structure–function relationships. BACKGROUND Lung ventilation heterogeneity due to the obstruction of small airways is an early and potentially reversible step in the progression of cystic fibrosis (CF). Individually, multiple breath washout (MBW), hyperpolarised (HP) gas ventilation-MRI and conventional structural lung imaging by CT have all been shown to be sensitive to early changes in the lungs before spirometry. The information they provide is complementary, and HP ventilation-MRI in particular has the potential to reveal airways obstruction and the functional consequences of regional structural changes detected with CT, as well as the nature of ventilation heterogeneity that prolongs gas washout in MBW. The aim of this study was to investigate the relative sensitivity of imaging and physiology assessments for the detection of early-stage lung disease in children with CF. In addition, we explored what insight functional ventilation imaging provides about the nature of ventilation abnormalities in the lungs in early CF and how these correlate with the more clinically scalable assessment of ventilation heterogeneity provided by MBW.