<unk>  occurs when an artery to the lung becomes blocked and part of the lung dies. It is most often caused by pulmonary embolism. Because of the dual blood supply to the lungs from both the bronchial circulation and the pulmonary circulation, this tissue is more resistant to<unk> . An occlusion of the bronchial circulation does not cause<unk> , but it can still occur in pulmonary embolism when the pulmonary circulation is blocked and the bronchial circulation cannot fully compensate for it. File:CT of<unk>  with reverse halo sign, annotated.CT scan of a<unk>  because of chronic pulmonary embolism (white arrow). The infarcted area (black arrow) has a reverse halo sign.
Lung infarction
Rib fracture
Pulmonary hemorrhage
Pleural empyema
Pulmonary hematoma
Lung abscess
Right heart strain
Globe rupture