Pseudoportal Doppler signal in the partially obstructed inferior vena cava.

Abstract

The Doppler sepctrum of the normal inferior vena cava (IVC) shows a majority of flow toward the right atrium, with wide variations in flow velocity and direction owing to effects of the cardiac and respiratory cycles. Seventeen subjects underwent duplex sonography: nine children after liver transplantation, two children with right upper quadrant neuroblastoma, and six healthy control subjects. In six children the spectrum obtained from the IVC bore a strong resemblance to the undirectional, low-velocity, continuous-flow pattern associated with the portal vein; these children included two children with biliary atresia and cirrhosis, two liver transplant recipients, and two children with IVC compression by neoplasm. In healthy children and adults, a pseudoportal Doppler signnal in the IVC can be generated by subcostal right upper quadrant compression. The pseudoportal IVC appears to be a sign of partial IVC obstruction. Knowledge of this potential piftfall and meticulous morphologic imaging can help prevent mistaking the IVC for a patent portal vein.