Ventilation heterogeneity of pediatric cystic fibrosis accessed via lung clearance index and hyperpolarized 129Xe MRI

Quantitative hyperpolarized ¹²⁹Xe ventilation MRI was compared to FEV₁, the spriometric gold standard for assessing lung function, and lung clearance index (LCI), an emerging pulmonary function test to assess global ventilation heterogeneity, in 12 pediatric cystic fibrosis subjects. A range of severity and spatial distributions of ¹²⁹Xe ventilation deficits were observed, with a ¹²⁹Xe ventilation defect percentage (VDP) of 18.0% ± 8.1%. VDP did not correlate with FEV₁ (p=0.45) but correlated very strongly with LCI (p=0.0001), suggesting that the spatial distribution of defects in the ¹²⁹Xe images represents obstructed areas of the lung that give rise to elevated LCI.