Superparamagnetic iron oxide-enhanced magnetic resonance imaging of the liver in beagle dogs.

The role of superparamagnetic iron oxide as a tissue-specific contrast medium has been established in humans, especially for hepatic imaging. Superparamagnetic iron oxide particles exhibit a tissue-specific biodistribution to the reticuloendothelial system, where they predominantly shorten transverse T2 relaxation time. Most hepatic tumors lack Kupffer cells; therefore, the T2 of tumors remains virtually unchanged after administration of superparamagnetic iron oxide.