Feasibility: Imaging Feasibility: The MRI pulse sequence that is the foundation for this study was previously developed and validated at 3T on a GE scanner by Dr. Parraga, who serves as Co-Principal Investigator of this proposed research.42 The MR acquisitions will be enabled using MR infrastructure at all 3 sites and 32 channel cardiac coils. Proof-of-concept for the presence of extensive emphysema is provided for a 25 year old with a history of prematurity and BPD, with significant MRI-evidence of widespread alveolar and acinar duct abnormalities that are consistent with emphysema Recruitment Feasibility: Each year, approximately 400 infants born < 28 weeks' gestation attend neonatal clinic follow-up visits at 18 months of age, at the three participating centres. As there are already established databases of these children at each site, identification of those eligible for study participation will be easily achieved.