ABSTRACT
Metastatic spread of tumors to the liver is common, with a high incidence from primary sites in the colon, oesophagus, pancreas, stomach, and lungs, and moderately frequent incidence from other primaries, including breast, melanoma, ovary, and kidney. 10-20% of patients with colorectal cancer have synchronous liver metastases at the time of their primary resection and about 50% of patients will develop metastases at some stage of the disease. Surgical resection or ablation of the liver lesions provides the only means of long term survival in these patients, but treatment success is dependant on the detection of all sites of intra-hepatic disease and the exclusion of disease outside the liver. Incomplete resection of intra-hepatic disease has no clinical benefit and does not prolong survival. Patients with fewer, small metachronous metastases have been found to have the most favourable prognosis, but recent data indicate that patients with more extensive disease may still benefit from resection. Consequently, surgery is becoming more aggressive, and the proportion of patients being referred for surgical consideration is rising. Moreover, since patients are being referred with earlier disease, often with multiple small lesions, the task of imaging is becoming more demanding. The role of preoperative imaging is to identify patients who will most benefit from hepatic resection by correctly locating all the metastases. Lesion characterization is as important as lesion detection in determining the management of these patients since a high proportion of small liver lesions, even in patients with a primary malignancy elsewhere, are benign. While failure to detect benign lesions doesn’t alter patient management, the incorrect interpretation of benign lesions as malignant may lead to an inappropriate surgical approach, or may wrongly preclude surgery as an option.
