Imaging of pulmonary infarction

Acute pulmonary embolism is associated with significant morbidity and mortality. Pulmonary hemorrhage and infarction are common complications of pulmonary embolism, occurring in about one-third of patients. Pulmonary hemorrhage and infarction classically present with pleuritic chest pain and hemoptysis. Recognition of pulmonary infarction on imaging is clinically important, as it may be the initial indication of unsuspected pulmonary embolism, leading to the correct diagnosis and therapy with anticoagulation. The imaging findings of pulmonary infarction are driven by the dual blood supply to the lung and have a typical appearance. In this article, we review the imaging appearances of pulmonary infarction as seen with multiple imaging modalities. The classic chest radiographic finding of pulmonary infarction is a peripheral opacity, the Hampton hump. The computed tomography findings of pulmonary infarction are because of the typical pattern of parenchymal injury in the setting of the dual blood supply to the lung. The infarct is usually a wedge-shaped opacity with its base toward a pleural surface, bulging borders, and truncated apex toward the hilum. The findings that have been shown to be useful in the differentiation of infarction from other causes of pulmonary parenchymal opacity include the following: diminished contrast enhancement of the infarcted lung parenchyma, internal air lucencies, and an enlarged vessel leading to the infarct.