Imaging of Right-to-Left Shunt in an Adult Patient with Unroofed Coronary Sinus with Persistent Left Superior Vena Cava: Diagnostic Clue and Pitfall

A 54-year-old woman with a history of multiple cardiac surgeries suffered from hypoxemia caused by a right-to-left intra-cardiac shunt due to coronary sinus (CS) anomaly with persistent left superior vena cava (PLSVC). Both the contrast echocardiography and enhanced computed tomography (CT) provided conclusive diagnosis of this rare congenital anomaly, which was overlooked for a long time. However, an important diagnostic clue was left-arm injection of the contrast media. In the present case, previously performed enhanced CT with its routine manner, i.e., contrast through the right arm, missed this anomaly. It is crucial to note that the unusual type of unroofed CS with PLSVC, presenting with an entirely right-to-left intra-cardiac shunt, cannot be delineated on an enhanced routine chest CT if the contrast media is injected through the right arm.