How will work be undertaken? Children 7-9 years old who were born extremely prematurely will be recruited to participate in this study. Participants will be identified from Neonatal Follow-up clinics they attended. The Investigators will enroll 20 children with BPD and 20 without BPD. Participants will have lung MR images taken, during which they need to lie still for a few minutes. PFT will also be performed, during which they will blow into a machine. Parents will be asked to complete questionnaires about breathing problems, their living conditions (environment) and any doctor visits or hospital stays. Medical charts will be reviewed for information about their birth.