Hepatobiliary cancers are highly lethal cancers including a spectrum ofinvasive carcinomas arising in the liver （hepatocellular carcinoma;HCC）， bile ducts （intrahepatic and extrahepatic cholangiocarcinoma）and gall bladder. Cholangiocarcinomas and gallbladder cancer arecollectively known as biliary tract cancers. In the United States, anestimated 26,190 and 9,250 cases will be diagnosed with liver orintrahepatic bile duct cancer and gallbladder cancer or other biliary tractcancer, respectively in 2011 with approximately 19,590 deaths fromliver or intrahepatic bile duct cancer, and 3,300 deaths due togallbladder cancer or other biliary tract cancer occurring during thatyear.
For patients with an incidental liver mass or nodule found onultrasound, the guidelines recommend evaluation using one or more ofthe imaging modalities （at least a 3-phase contrast-enhanced CT orMRI including the arterial and portal venous phase） to determine theperfusion characteristics, extent and the number of lesions, vascularanatomy and extrahepatic disease. The number and type of imaging isdependent on the size of the liver mass or nodule.
Liver lesions less than 1 cm should be evaluated by at least a 3-phasecontrast-enhanced CT or MRI or CEUS every 3-6 months, withenlarging lesions evaluated according to size. Patients with lesionsstable in size should be followed with imaging every 3-6 months usingthe same imaging modality that was first used to identify the nodules.