Developmental anomalies of the superior vena cava and its tributaries: What the radiologist needs to know?

Deviations from the normal process of embryogenesis can result in various developmental anomalies of the superior vena cava (SVC). While these anomalies are often asymptomatic, they assume clinical importance during interventions such as central venous catheterisations and pacemaker implantations and during cardiothoracic surgeries while instituting cardiopulmonary bypass and for creation of cavo-pulmonary connections. Role of imaging in identifying these anomalies is indispensable. Cross-sectional imaging techniques like CT venography and magnetic resonance (MR) venography allow direct visualisation and consequently increased detection of anomalies. CT venography plays an important role in detection of SVC anomalies as it is readily available, has excellent spatial resolution, short acquisition times and potential for reconstruction of images in multiple planes. This pictorial review focuses on the developmental anomalies of the SVC and its tributaries highlighting their embryological basis, imaging appearances on CT venography and potential clinical implications, where relevant.