Abstract
Crossed pulmonary arteries are a quite rare form of pulmonary arterial malposition. In this anomaly, the left pulmonary artery originates from the pulmonary trunk to the right and usually above the origin of the right pulmonary artery. Both pulmonary arteries cross each other on their course to each respective lung. We presented a case of a Chinese infant with crossed pulmonary arteries. Physical examination showed a mild cyanosis and continuous machine-like heart murmur in the 2 intercostal space at the left sternal border. An echocardiogram revealed pulmonary hypertension, atrial septal defect, patent ductus arteriosus and ostial stenosis in the inferior left pulmonary vein. Dual-source CT angiography was performed for further evaluation of pulmonary trunk and its branches. Dual-source CT angiography showed origin of left pulmonary artery from the pulmonary trunk in a plane superior to that of the right pulmonary artery. The branch pulmonary arteries then crisscrossed as they coursed to their respective lungs. In summary, we report an infant with crossed pulmonary arteries who was diagnosed during dual-source CT angiography. Three-dimensional reconstruction is useful for visualizing this condition. Knowledge of this rare anomaly will help in the differential diagnosis of pulmonary artery abnormalities.