Computed tomography for major aortopulmonary collateral arteries: a roadmap to unifocalized pulmonary arterial flow

In conjunction with catheter angiography, high-resolution, isotropic, three-dimensional computed tomography mapping of major aortopulmonary collateral arteries is useful for delineating complex thoracic arterial anatomy and has been increasingly utilized in patients with pulmonary atresia and ventricular septal defect. The presence, confluence, and size of the central (mediastinal native) pulmonary artery; the presence and course of a patent ductus arteriosus; the number of collateral arteries; the number of lung segments supplied by each collateral artery; significant distal pulmonary artery stenoses; and isolated or dual blood supply in each lung segment can be evaluated using computed tomography mapping. The detailed mapping can substantially reduce procedural time for catheter angiography, which delivers a higher radiation dose than computed tomography does, and is useful for surgical planning. Furthermore, the effect of surgical treatments including unifocalization and rehabilitation can be monitored with computed tomography mapping. In addition to pulmonary atresia with ventricular septal defect, a major aortopulmonary collateral artery may be observed in other cardiac defects associated with pulmonary atresia, scimitar syndrome, and systemic arterial supply to normal lung. Lastly, the review briefly discusses promising future applications of computed tomography mapping focusing on quantification of arterial and lung volumes.