Imaging primary and metastatic cancer of the liver.

Either CT or MRI can be used as a primary screening test for liver masses in a patient with a known or suspected malignancy. A number of variations in techniques are available for both CT and MRI, and combinations of these techniques are often required to increase the detectability rate for hepatic lesions. Whether CT or MRI is chosen as an initial screening technique depends upon the particular patient and the institution. After a liver lesion has been identified, attempts should be made to obtain a specific diagnosis. Certain liver masses may have a specific CT appearance, especially when they are calcified. With some benign lesions a specific diagnosis is possible using imaging techniques, and in these instances CT and a supplemental radionuclide study may be of complimentary value. These include cavernous hemangioma, focal fatty liver, and focal nodular hyperplasia. Another group of lesions have a CT or an MRI appearance that is suggestive for a specific diagnosis, but may require confirmation with a biopsy or other tests. These include hepatoma, which may present as a mass with portal vein thrombosis, hepatic adenoma, which may appear as a mass with central hemorrhage, focal nodular hyperplasia may occur as a mass with a central stellate scar (on CT), or a cavernous hemangioma, which fulfills specific CT or MRI criteria. A final group of lesions consists of masses without a characteristic or suggestive CT or MRI appearance. These lesions will require biopsy for final diagnosis.