Two patterns of blood pooling giant hemangiomas on Tc-99m RBC scintigraphy

Tc-99m RBC scintigraphy is a highly specific diagnostic test of hepatic hemangiomas. The characteristic findings of a hemangioma on dynamic contrast computed tomography (CT) or magnetic resonance imaging (MRI) are peripheral enhancement followed by progressive centripetal central enhancement of the lesion. The reverse pattern, central enhancement with subsequent centrifugal peripheral enhancement is rarely seen. These filling patterns are not usually recognized on Tc-99m RBC scintigraphy. The authors describe two patients with giant hemangiomas in the right lobe of the liver who had different filling patterns on sequential Tc-99m RBC scintigrams. One patient had peripheral enhancement with subsequent central filling (centripetal enhancement), and the other had central enhancement with subsequent peripheral filling (centrifugal enhancement).