The inferior vena caval pseudo thrombus sign: diagnosis by dynamic CT after arm vein injection.

Pseudothrombus of the inferior vena cava has been observed after pedal infusion. Previously it has been suggested that this pitfall results from technique and that this finding would not be observed following fast computed tomographic scanning after arm vein injection. However, we have observed similar flow artifacts using the latter technique. A scan obtained up to 14 minutes after the start of the bolus or reinjection with delayed dynamic scanning can exclude thrombus without further investigation.