CT angiography of systemic to pulmonary venous shunt in superior vena cava obstruction.

Superior vena cava obstruction is associated with multiple venous collaterals. There is an unusual pathway involving pulmonary venous collaterals in which systemic veins drain directly into the left heart, resulting in a right-to-left shunt. We report here a rare case of systemic to pulmonary venous shunt on both hemithoraces in superior vena cava obstruction associated with Budd-Chiari syndrome due to coagulopathy which was diagnosed by multidetector computed tomography angiography.