Liver and Spleen

Abstract

AbstractNuclear medicine studies for the evaluation of liver, spleen, and biliary tract pathologies include a number of tests performed with various radiotracers. These imaging modalities are based on an assessment of the various histological components of the liver and spleen and their functional characteristics. Hepatobiliary scintigraphy (HBS) evaluates the function of the hepatocytes and the biliary system. Liver and spleen scintigraphy with [99mTc]-labelled colloid tracks active tracer phagocytosis by the reticuloendothelial system (RES) of the liver, spleen, and bone marrow. Approximately 80–90% of tracer is taken by the liver, 5–10% by the spleen, and the remainder by the bone marrow. The physiologic basis for spleen scintigraphy with heat damaged red blood cells (DRBCs) is the ability of this organ to trap and remove deformed and damaged RBCs from circulation. This method involves drawing blood, in vitro labelling RBCs with [99mTc], and inducing damage to their cell membrane with controlled heating. Following reinjection of DRBCs splenic tissue can be identified with high sensitivity and specificity. Unlike labelled colloid scans and HBS, liver and spleen scintigraphy with [99mTc]-labelled RBCs can be highly specific in the evaluation of vascularity and blood pool of focal liver lesions.