[Computed tomographic imaging of collateral pathways in stenoses of the large mediastinal veins].

Scans of angio-computed tomography (CT) of 53 patients suffering from mediastinal space-occupying growths were reviewed: 16 patients showed stenosis of mediastinal veins with demonstration of subcutaneous venous channels, 17 showed an obstruction without collateral pathways and 20 patients had normal mediastinal vessels. Two-thirds of the cases with external vein compression were caused by bronchogenic carcinoma. The degree of obstruction in patients showing collateral circulation was between 70 and 100 percent and significantly greater than in patients without collaterals (40%). The most important collaterals bypassing the upper mediastinal veins are discussed.