We illustrate the spectrum of venous collateral pathways caused by the thoracic central venous obstruction with direct spiral computed tomography (CT) venography and 3-dimensional reconstruction images. Venous structures that can be demonstrated with CT venography include the jugular veins; the subclavian and brachioce-phalic (innominate) veins; the internal and lateral thoracic veins; the superior and inferior venae cavae; the pericardiophrenic veins; the azygos, hemiazygos, and accessory hemiazygos veins; and the intercostal veins.