The liver is the second most common location of metastases following the lymph nodes. The accurate characterization of focal liver lesions in oncology patients is especially important because of the high prevalence of benign liver lesions and the possibility of co-existing benign and malignant lesions. The exact interpretation of these lesions is crucial for therapeutic decisions and thus for the prognosis of the patient. It is essential to detect all focal liver lesions and to distinguish benign from malignant lesions, especially in the management of oncology patients. Numerous imaging modalities are available for these challenges in the daily routine. An extensive understanding of the advantages and limitations of the various imaging modalities and knowledge of the morphology and the typical and atypical appearances of the different metastases is important. This review explains the radiological criteria for various metastases in different modalities. To evaluate the individual prognosis and risk assessment preoperatively, functional imaging is necessary. These personalized pretherapeutic diagnostics are discussed.