Health Issue: Bronchopulmonary dysplasia (BPD), a chronic lung disease, is the most common complication of being born premature. Damage to the still developing lung stops the normal formation of the alveoli. Young adults with a history of BPD have lower lung function, early heart disease, and increased risk of death, compared to those without BPD. Recently, it has been reported that they may also develop a type of lung disease typically seen in older adults with a longstanding history of smoking. The severity of lung disease is usually measured using pulmonary function tests (PFT), but these tests may be normal, even in the presence of important changes in the fine structure of the lung. Such structural changes may be early markers of future lung disease and can be detected using lung magnetic resonance imaging (MRI). Unlike other ways of imaging the lungs, MRI does not expose people to harmful X-rays. To date, no studies have been done to examine the fine structure of the lung of school-aged children who had a history of BPD, to determine whether there are signs of lung disease that might not otherwise be obvious. This is important because once armed with this information, preventive measures can be taken to avoid worsening of lung disease.