CT of unusual mediastinal vascular abnormalities.

The previously unreported CT findings of supracardiac anomalous pulmonary venous return and Takayasu arteritis are presented. CT demonstration of a left vertical vein and an enlarged superior vena cava strongly suggests a diagnosis of supracardiac anomalous venous return. Dynamic scanning of the mediastinum following bolus injection of urographic contrast with close attention to vascular enhancement patterns is required to suggest a diagnosis of Takayasu arteritis. CT is not the preferred diagnostic modality for either entity, but may prove definitive in some patients and may serve to triage other patients to the appropriate diagnostic modalities.