Patent Ductus Arteriosus

  • Etiology: failure of closure of the fetal ductus arteriosus connecting the main pulmonary artery to the descending aorta leading to a left to right shunt
  • CXR: cardiomegaly and increased pulmonary blood flow that increases over time
  • Angiogram: simultaneous filling of the pulmonary artery and aorta when either is injected
  • Imaging: 33% have a ductus diverticulum which is a developmental outpouching aortic isthmus where ductus arteriosus attaches which also happens to be the site of 90% of post-traumatic aortic injuries so it should not be mistaken for a traumatic aortic pseudoaneurysm
  • Complications: prostaglandin E – keeps patent ductus arteriosus open in patent ductus arteriosus dependent congenital heart diseases (pulmonary atresia, hypoplastic left heart syndrome), can cause periostitis, can cause gastric mucosal hypertrophy mimicing hypertrophic pyloric stenosis
  • Complications: indomethacin – closes patent ductus arteriosus, can cause gastrointestinal perforation
  • Clinical: in fetus gas exchange occurs at placenta and thus ductus arteriosus allows oxygenated blood from placenta to bypass high resistance pulmonary bed and enter systemic circulation, usually closes within 24-48 hours of birth in term neonate, acyanotic

Radiology Cases of Patent Ductus Arteriosus

CXR AP at 1 day of life (above) and 1 year of life (below) shows interval development of cardiomegaly and pulmonary vascular congestion.
CXR of patent ductus arteriosus ductus diverticulum
CXR AP shows mild cardiomegaly and pulmonary vascular congestion along with an extra soft tissue mass just to the left of the spine near the presumed position of the ductus arteriosus.
Angiogram of patent ductus arteriosus
AP angiogram while injecting the pulmonary artery shows simultaneous filling of the descending aorta.
Angiogram of patent ductus arteriosus / PDA
AP image from a ventricular injection in an angiogram shows simultaneous opacification of the aorta and main pulmonary artery.
CT of interrupted aortic arch
Axial CT with contrast of the heart (above), obtained in a venous phase, shows discontinuity of the ascending and descending aorta while the sagittal image (below right) shows a dilated patent ductus arteriosus reconstituting the descending aorta and the coronal image (below left) shows dextrocardia.