Marked enlargement of the left lobe of the liver causing a false-positive spleen image

In 10 patients with a markedly enlarged left lobe of the liver, the posterior (prone) views (99mTc-sulfur colloid) revealed a false-positive splenic defect. In 1 case the defect was also apparent in the anterior view. In all but 1 case this pseudodefect was not present in the posterior image obtained standing up. Use of a spleen-specific or liver-specific radionuclide agent was necessary in that case. The authors caution against diagnosis from an apparently abnormal posterior image unless proved by other measures.