Crossed pulmonary arteries: report of two cases with emphasis on three-dimensional helical computed tomographic imaging.

Crossed pulmonary arteries are due to an anomalous origin of both pulmonary arteries from the main pulmonary trunk. This anatomy is often associated with other congenital cardiac and extracardiac diseases. We report two neonates with complex congenital heart disease who had this disorder, which was detected during cardiac computed tomography (CT) with three-dimensional reconstruction but not during echocardiography or angiography. The first patient was a 3-day-old male neonate who had tachypnea and feeding problems since birth. Cardiac CT showed crossed pulmonary arteries, type B interruption of the aortic arch, a ventricular septal defect, and a large patent ductus arteriosus. He received an emergency T-colostomy at 3 days of age because of severe bowel distention. Low-type imperforated anus was diagnosed. His postoperative course was complicated with fluctuated saturation, seizure, hypocalcemia, hyperphosphatemia, and sepsis. Also found were cardiac defects, abnormal facies, thymic hypoplasia, cleft palate, hypocalcemia, and a variable deletion on chromosome 22q11 (CATCH 22 disorder). Because of his poor prognosis, the patient was transferred to another hospital on day 16 for further care, at the family's request. The other patient was a 5-day-old female neonate who had a heart murmur since birth. Cardiac CT showed crossed pulmonary arteries, truncus arteriosus, type A interruption of the aortic arch, a ventricular septal defect, an atrial septal defect, and a large patent ductus arteriosus. She received complete surgical correction, including division of the patent ductus arteriosus and repair of the other defects. Intermittent respiratory distress and decreased blood pressure complicated her postoperative course, and she died on the eighth day after surgery. Crossed pulmonary arteries complicated accurate interpretation of two-dimensional echocardiographs of the great vessels, as well as the course and location of catheters during cardiac catheterization. Three-dimensional CT provided a noninvasive approach to clearly recognize these malformations and the related anatomic structures. This information is important in planning and performing surgery in neonates with crossed pulmonary arteries.