Chronic obstructive pulmonary disease (COPD) affects an estimated 6.4% and interstitial lung disease (ILD) affects an estimated 0.3% of adults in the US. COPD is defined by airflow obstruction on spirometry, as indicated by a low ratio of forced expiratory volume in the first second to forced vital capacity. Emphysema and chronic bronchitis are the main processes underlying airflow obstruction in COPD. Emphysema is visualized on chest computed tomography (CT) as foci of decreased lung attenuation due to alveolar tissue loss and results in increased lung compliance and volume (hyperinflation). In contrast, most ILDs cause fibroinflammatory parenchymal infiltration that reduces lung compliance and volumes, resulting in a restrictive ventilatory defect on pulmonary function testing. CT findings that indicate ILD include ground-glass/reticular opacities, traction bronchiectasis/bronchiolectasis, or honeycombing.