For another resource on how to approach focal liver lesions, see Liver Lesion–American College of Radiology Appropriateness Criteria 2014.
ACG Clinical Guideline: The Diagnosis and Management of Focal Liver Lesions, [PubMed Abstract], [Full Text PDF]. The American Journal of Gastroenterology 109, 1328-1347 (September 2014) | doi:10.1038/ajg.2014.213. The following is all from the guideline: