NUCLEAR-MEDICINE IMAGING IN THE DIFFERENTIAL-DIAGNOSIS OF SPACE-OCCUPYING LESIONS OF THE LIVER

Nuclear methods allow for the differential diagnosis of tumors originating from the liver as well as for the characterization of tissue foreign to the liver, such as metastases. Tc-99m-labeled radiopharmaceuticals, namely, colloid and iminodiacetic acid derivatives assess the function of the reticuloendothelial system in the liver, the hepatocyte and the biliary system. Lesions such as focal nodular hyperplasia, adenoma and hepatocellular carcinoma can be differentiated by their appearance when studies with these radiopharmaceuticals are performed. Lesions caused by tissue foreign to the liver can be specifically identified by monoclonal antibodies against antigens like carcinoembryonic antigen or by radiopharmaceuticals with specific affinity to the tumor such as metaiodobenzyl-guanidine. Radioimmunoscintigraphy, in particular, provides a high accuracy in the detection of malignant disease and its secondaries in the liver. A sensitivity of 87% with a specificity of 97% can be reached. Nuclear medicine has a considerable potential to diagnose lesions of the liver accurately.