CT
Axial C+ CTPA
Sagittal C+ CTPA
As expected, artificial tricuspid valves and a huge thrombus in the right atrium were found. However, upon contrast injection in the pulmonary arterial phase, pulmonary artery and aorta showed reversal of the expected enhancement: contrast followed the superior vena cava then flowed through an unsual "bag of worms"-like ductus into the superior left pulmonary vein, thus creating a right-to-left shunt. This so-called ductus was located around the right hilar region and included the azygos vein.
The rest of the cardiac anatomy was normal, with situs solitus of the viscera and atria (S), ventricular D-loop (D), and solitus-related great arteries (S): S, D, S.
No pulmonary embolism was seen.
CT evidence showed this unusual right-to-left shunt causing dyspnoea.
This case emphasized an unusual pathway through preexisting bronchial venous plexuses which link the right atrium to the left superior pulmonary vein.