The lung has a dual vascular supply; therefore infarction is uncommon, unless there is preexisting pulmonary or cardiac disease resulting in a low flow state. Pulmonary infarcts resulting from occlusion of pulmonary artery branches are hemorrhagic, wedge-shaped, and often pleural based. Infarcts resulting from vasculitis with luminal occlusion are often round, with a central thrombosed blood vessel.