Current status of imaging and emerging techniques to evaluate liver metastases from colorectal carcinoma.

Colorectal cancer is the third most common cancer diagnosed in both men and women in the United States. Liver is a common site of tumor spread and in approximately 30% of the cases; synchronous liver disease is present at the time of diagnosis. Early detection of liver metastases is crucial to appropriately select patients who may benefit from hepatic resection among those needing chemotherapy, to improve 5-year survival. Advances in imaging techniques have contributed greatly to the management of these patients. Multidetector computed tomography is the most useful test for initial staging and in posttreatment surveillance settings. Magnetic resonance imaging is considered superior to multidetector computed tomography and positron emission tomography for the detection and characterization of small lesions and for liver evaluation in the presence of background fatty liver changes. Positron emission tomography-computed tomography has a problem-solving role in the detection of distant metastasis and in posttreatment evaluation. The advanced imaging methods also serve a role in selecting appropriate patients for radiologically targeted therapies and in monitoring response to conventional and novel therapies.