Abstract Rationale Very preterm infants (VPT, 32 weeks gestation) often develop bronchopulmonary dysplasia (BPD), a chronic lung disease that disrupts alveolar and pulmonary vascular development, but long-term sequelae of BPD are poorly understood. Hyperpolarized xenon (Xe) magnetic resonance imaging (MRI) can measure microstructural injury via the apparent diffusion coefficient (ADC, a measure of alveolar-airspace size) and via xenon’s solubility in tissue and red blood cells (RBC) to evaluate regional gas exchange. The objective of this study was to investigate the extent and severity of abnormal alveolar microstructure (elevated ADC and impaired gas exchange indicated by reduced 129Xe RBC-transfer) in school-age and older subjects born VPT (with severe BPD and without BPD) and compare to term-born controls. Methods We recruited subjects from the BPD Center at Cincinnati Children’s Hospital and the greater Cincinnati area on IRB-approved protocols with informed consent for 129Xe MRI. We imaged 47 subjects born either VPT (n = 17 without BPD; n = 13 with severe BPD, determined in infancy) or term (n = 17) at school age and older (8.4±6.6 yrs without BPD, 12±10.6 yrs with BPD, 6.8±0.2 yrs term controls). BPD was defined according to the 2018 NICHD/NHLBI consensus definition1. Xe ADC and gas-exchange MRI were acquired at 3T with gradient-echo and radial sequences under published imaging protocols2. Results Subjects with severe BPD showed significantly increased mean ADC versus term controls (0.0334±0.033 vs 0.0245±0.003 cm2/sec, p = 0.0016), with higher spatial variation in all BPD patients (coefficient of variation: 11.34% for term controls, 26.53% for VPT without BPD, and 23.16% for VPT with severe BPD). 27% of all VPT subjects (18% without BPD and 38% with BPD) showed ongoing alveolar simplification based on elevated mean ADC values beyond 3 standard deviations of the mean ADC for term controls. 129Xe gas exchange parameters showed no significant differences between VPT and term groups in this modest sample size. Conclusions At and after school age, alveolar simplification in VPT subjects is significant with approximately 1/6 of infants born VPT having no defined lung disease but demonstrate evidence of alveolar simplification3. Our findings support 129Xe MRI as a method to individually characterize lung microstructural injury in VPT patients and suggest that clinical BPD diagnosis may not predict those who have or will develop enlarged alveolar spaces. Alveolar simplification appears to be disproportionate to original clinical BPD diagnosis at 36 weeks corrected gestational age. References 1.Higgins et al,J Pediatr(2018); 2.Niedbalski et al,MRM(2021); 3.Förster et al,ERJ Open Research(2025) This abstract is funded by: NIH NHLBI
Sheak et al. (Fri,) studied this question.