Mediastinal widening--a valuable radiographic sign of superior vena cava thrombosis.

Thrombosis due to indwelling intravenous catheters has become increasingly recognized as an important cause of the benign superior vena cava (SVC) obstruction. We evaluated the PA chest radiographs of nine patients with SVC thrombosis related to Hickman catheter insertion. All nine patients showed mediastinal widening at the time of developing SVC thrombosis and four patients had radiographic signs before the onset of symptoms. Five patients demonstrated lateral displacement of the Hickman catheter with the development of SVC thrombosis. The development of superior mediastinal widening is a valuable sign of SVC thrombosis and its recognition may allow earlier diagnosis and treatment of this condition.