thus , it is no longer necessary to use cavography -- except as a supplementary method mainly in cases where with sonography it is difficult to differentiate between an incomplete and a complete occlusion of the vena cava or between a cone-shaped invasion of the neoplastic thrombus into the inferior vena cava and an infiltration of the tumor into the wall of the vena cava .
C0042458
inferior vena
C0042460
vena cava