A pulmonary contusion refers to an interstitial and / or alveolar lung injury without any frank laceration. It usually occurs secondary to non-penetrating trauma.
While contusion can affect anyone, children are considered more susceptible due to chest wall greater pliability in that age group.
In most cases the findings are manifest at the time of the initial examination and show little tendency to increase in severity with subsequent examinations. Radiographic clearing of pulmonary contusion is relatively rapid, and the signs of contusion have often resolved within 48 hours. Features often does not localize in a lobar or segmental pattern.
Not sensitive. Faint patchy consolidative regions following history of blunt trauma. Usually shows rapid improvement with time (days) .
Typically seen as focal, non segmental (typically crescentic) areas of parenchymal opacification. Can have sub-pleural sparing with smaller contusions which can be a distinguishing feature. Commoner posteriorly and in lower lobes.
General imaging differential considerations include