Inferior vena cava CT pseudothrombus produced by rapid arm-vein contrast infusion

Laminar flow within the inferior vena cava can cause artifacts that may simulate thrombus if a foot-vein infusion is used. A 'pseudothrombus' artifact within the suprarenal inferior vena cava produced by rapid infusion of contrast material through an arm vein is reported. This artifact was noted in 25 patients in a 6 month period and was believed to be from laminar flow of renal venous effluent of increased opacity around less opacified infrarenal caval contents. Differentiation from true thrombus can be made by the use of delayed scans as well as the increased density and relatively poor margination of the artifact.