Characterization of Indeterminate Liver Lesions on CT and MRI With Contrast-Enhanced Ultrasound: What Is the Evidence?

CT or MRI is most commonly used for characterizing focal hepatic lesions. However, findings on CT and MRI are occasionally indeterminate. Contrast-enhanced ultrasound (CEUS), with its unique characteristics as a purely intravascular contrast agent and real-time evaluation of enhancement, is a useful next step. The purpose of this article is to review the evidence for performing CEUS in the assessment of indeterminate hepatic lesions seen on CT and MRI. CEUS is a useful problem-solving tool in the evaluation of liver lesions that are indeterminate on CT and MRI. Uses include detection of arterial phase hyperenhancement; differentiation between hepatocellular carcinoma and intrahepatic cholangiocarcinoma; determination of benign versus malignant tumor thrombus, benign versus neoplastic cystic hepatic lesions, and hepatocellular adenoma versus focal nodular hyperplasia; and monitoring for recurrence in postablative therapies. CEUS can help establish a confident diagnosis and determine the need for further invasive diagnosis or treatment.