CT diagnosis of mediastinal and thoracic inlet venous obstruction.

The diagnosis of mediastinal or thoracic inlet venous obstruction can be made reliably by chest computed tomography (CT), and depends on the opacification of collateral venous channels during the continuous infusion of intravenous contrast media. The sectional anatomy of these collateral pathways is illustrated by examples from 50 consecutive patients. An understanding of this anatomy facilitates the diagnosis of obstruction of the superior vena cava or its major tributaries during routine chest CT. Although CT was inferior to contrast venography in opacifying peripheral collateral veins and determining the degree of obstruction, the information provided by CT obviated venography in most patients in this series. CT may be the initial procedure of choice in suspected mediastinal venous obstruction.