Computed tomography findings in pseudothrombosis of the iliofemoral vein.

Computed tomography findings in 3 patients with apparent thrombosis of an iliofemoral vein due to mixing artifact related to venous collateral formation are presented, 1 with portosystemic collaterals and 2 with collaterals secondary to subclavian vein thrombosis. Mixing artifact or asymmetric enhancement related to collateral formation should be considered for an apparent thrombus in the iliofemoral vein. Examination of axial and reformatted images may facilitate recognition and help avoid an erroneous diagnosis of deep venous thrombosis.