This is particularly concerning since there is increasing recognition that preterm born adults have a significant burden of early lung disease. Emphysema has been reported in young adults with a history of prematurity less extreme than the prematurity seen today. X-ray computed tomography (CT) imaging detects pulmonary abnormalities in 98%, with emphysema in 47% of this less premature cohort as young adults. Not all of those with CT abnormalities, however, have impaired pulmonary function tests (PFTs), thus highlighting the limitations of conventional PFTs to detect disease. In childhood, PFTs, while very powerful indicators of global lung health, may be relatively insensitive to detect early pulmonary structural changes and regional lung abnormalities. Pulmonary dysfunction may not cause symptoms at rest or correlate with PFTs in childhood, but may become apparent with exercise, infection, or aging. Structural changes in the lung parenchyma may already be present in childhood and may be earlier markers of current and future respiratory disease than conventional PFT. Such changes may be detected with pulmonary MRI of the lung, as has been shown in COPD and in pilot work in BPD MRI has significant advantages over CT, including lack of exposure to ionizing radiation and high resolution of fine tissue structure. Recent advances in pulmonary MRI, including ultra-short echo time pulse sequences, generate pulmonary images with enhanced parenchymal signal intensity which rival CT images for visualization of lung parenchyma and vasculature. MRI is emerging as a research tool and may ultimately replace CT for pediatric thoracic imaging tasks and serial evaluations.