Use of radiologic techniques to screen for hepatocellular carcinoma.

The role of imaging in screening and evaluation of cirrhotic patients is to assess the extent of cirrhosis and portal hypertension (liver morphology, varices, ascites, vessel patency) and to detect hepatocellular carcinoma (HCC). Ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI) have valuable roles, with catheter angiography usually reserved for specific problem solving. Ultrasonography is highly operator-dependent, and detection of focal masses is often difficult or impossible because of large patient body habitus and hepatic steatosis and fibrosis, which attenuate the ultrasound beam. For sonography, as well as CT and MRI, the use of intravenous contrast material with multiphasic imaging (arterial, portal venous, and delayed) is essential to accurately depict the morphology and hemodynamics of focal hepatic lesions. Computed tomography and MRI are highly accurate in diagnosis of large HCC but are much less accurate for lesions less than 2 cm in diameter. Many factors influence the choice and timing of imaging tests, including the etiology of the chronic liver disease, the elevation of serum tumor markers, and the availability and excellence of equipment and personnel. In our practice, helical multiphasic CT is obtained at least every 12 months, more frequently in patients judged to be at high risk for HCC.