Image Phenotyping of Preterm-Born Children Using Hyperpolarized Xe Lung Magnetic Resonance Imaging and Multiple-Breath Washout.

Preterm birth is associated with low lung function in childhood, but little is known about the lung microstructure in childhood. We assessed the differential associations between the historical diagnosis of bronchopulmonary dysplasia (BPD) and current lung function phenotypes on lung ventilation and microstructure in preterm-born children using hyperpolarized Xe ventilation and diffusion-weighted magnetic resonance imaging (MRI) and multiple-breath washout (MBW). Data were available from 63 children (aged 9-13 yr), including 44 born preterm (⩽34 weeks' gestation) and 19 term-born control subjects (⩾37 weeks' gestation). Preterm-born children were classified, using spirometry, as prematurity-associated obstructive lung disease (POLD; FEV < lower limit of normal [LLN] and FEV/FVC < LLN), prematurity-associated preserved ratio of impaired spirometry (FEV < LLN and FEV/FVC ⩾ LLN), preterm-(FEV ⩾ LLN) and term-born control subjects, and those with and without BPD. Ventilation heterogeneity metrics were derived from Xe ventilation MRI and SF MBW. Alveolar microstructural dimensions were derived from Xe diffusion-weighted MRI. Xe ventilation defect percentage and ventilation heterogeneity index were significantly increased in preterm-born children with POLD. In contrast, mean Xe apparent diffusion coefficient, Xe apparent diffusion coefficient interquartile range, and Xe mean alveolar dimension interquartile range were significantly increased in preterm-born children with BPD, suggesting changes of alveolar dimensions. MBW metrics were all significantly increased in the POLD group compared with preterm- and term-born control subjects. Linear regression confirmed the differential effects of obstructive disease on ventilation defects and BPD on lung microstructure. We show that ventilation abnormalities are associated with POLD, and BPD in infancy is associated with abnormal lung microstructure.