Imaging of primary and metastatic liver tumors.

Innovative liver surgical techniques are allowing improved survival for patients with liver tumors. To effectively plan this surgery, both the number and precise location of all lesions must be accurately documented. Numerous technical advances have occurred in cross-sectional imaging techniques for evaluating liver tumors. These improvements have increased the sensitivity of US, CT and MR for detecting primary and metastatic liver neoplasms. Depending on the specific clinical information required, such as extrahepatic spread of diseases or hepatic vascular invasion, each modality has its strengths and drawbacks. The specific choice of technique should be decided in consultation with the radiologist who interprets the studies. Both benign and malignant lesions may coexist in the same liver and, because this affects patient management and prognosis, care should be taken to evaluate each lesion that is identified. Tumors also may be simulated by pseudolesions such as focal fatty sparing or infiltration, regenerative nodules, or hepatic arterial perfusion defects. To best evaluate liver malignancies, a sensible combination of imaging modalities, depending on the patient population, radiologic strengths, and imaging equipment available, is recommended to provide the best overall assessment of the number and location of liver neoplasms.