Radiographic appearance of bullet tracks in the lung

Penetrating missile or bullet wounds to the lung result in a number of abnormalities visible on chest radiographs. One finding that is unique to pulmonary parenchyma is the bullet track, which occurs along the course of a bullet as it traverses the lung. A bullet track may occur in the lung because of this organ's low specific gravity and high elasticity. In other tissues, such as liver and brain, that have higher specific gravities and lower elastic content, bullet tracks are rarely, if ever, noted because widespread destruction usually occurs. Bullet tracks may have a delayed appearance on chest radiographs, and thus may cause confusion in interpretation if a history of injury is not elicited. With the increase in violet confrontations in the United States, it is more and more likely that radiologists will be asked to interpret chest radiographs of patients who have had penetrating bullet injuries to the thorax. In this pictorial essay, we illustrate the appearance of bullet tracks in lung on chest radiographs.