enlarged artery in lungenlarged main pulmonary arterypulmonary artery thrombosispulmonary artery blockagepulmonary artery aneurysmpulmonary arterial pressurepulmonary artery embolismpulmonary artery stenosissevere pulmonary arterial hypertensionperipheral pulmonary artery stenosispulmonary artery occlusion pressureenlarged pulmonary artery cxr