Superior Vena Cava Obstruction with Intrahepatic and Systemic–Pulmonary Venous Right-to-Left Shunts

The diagnosis of superior vena cava obstruction is based on demonstration of venous collateral circulation. Computed tomography (CT) is the best imaging modality for this disease. Nuclear medicine is also helpful in showing caval flow compromise through scintigraphic venography and abnormal radiotracer accumulation from developed venous collaterals. The authors present a case of superior vena cava obstruction with the two less common venous collateral pathways described in the imaging literature: intrahepatic and right-to-left shunts. These shunts are demonstrated by technetium-99m MAA lung scintigraphy with CT and venographic correlation. Characteristics of these two shunts are discussed with a brief review of the literature.