Background: Chronic lung disease, the most prevalent long-term complication after premature birth, lacks the routine characterization of structural changes.

Objective: We compared changes to lung structure and perfusion using magnetic resonance imaging (MRI) in preterm infants born <32 weeks gestation near-term and preschool age.

Methods: Near-term (n=88) and 4-8 years of age (n=26), preterms with/without Bronchopulmonary Dysplasia (BPD) underwent 3T MRI while spontaneously breathing (n=16 serial measurements; n=29 lung follow-up questionnaires). Standardized image assessment (5-point Likert scale) of coronal/axial/sagittal T2-weighted single-shot fast-spin-echo sequences included ?emphysema?, ?interstitial enhancement?, ?airway accentuation?, and ?ventilation inhomogeneity?. Pulmonary artery (PA) flow and area as well as cardiac function was quantified in flow sensitive gradient-echo sequences.

Results: MRI-scoring revealed a persisting ?emphysema? phenotype in moderate/severe BPD children (term p=0.0017, preschool p=0.039; vs. noBPD). In contrast, changes in ?interstitial enhancement? only characterized BPD at term in the overall group (term p=0.0016, preschool p=0.69; vs. noBPD), while changes persisted when stratifying for clinical risk factors (postnatal infections, gender, and/or infections after discharge). ?Airway accentuation? was detected in mild BPD cases at preschool age. Abnormalities in PA flow, present in preterms with moderate/severe BPD at term, identified children with BPD at preschool age (AUC=0.85 [0.65-1.00]).

Conclusions: The identification of persisting structural and functional changes in the BPD lung by MRI could inform treatment and monitoring strategies.