Clinical value of MRI liver-specific contrast agents: a tailored examination for a confident non-invasive diagnosis of focal liver lesions

Screening of the liver for hepatic lesion detection and characterization is usually performed with either ultrasound or CT. However, both techniques are suboptimal for liver lesion characterization and magnetic resonance (MR) imaging has emerged as the preferred radiological investigation. In addition to unenhanced MR imaging techniques, contrast-enhanced MR imaging can demonstrate tissue-specific physiological information, thereby facilitating liver lesion characterization. Currently, the classes of contrast agents available for MR imaging of the liver include non-tissue-specific extracellular gadolinium chelates and tissue-specific hepatobiliary or reticuloendothelial agents. In this review, we describe the MR features of the more common focal hepatic lesions, as well as appropriate imaging protocols. A special emphasis is placed on the clinical use of non-specific and liver-specific contrast agents for differentiation of focal liver lesions. This may aid in the accurate diagnostic workup of patients in order to avoid invasive procedures, such as biopsy, for lesion characterization. A diagnostic strategy that considers the clinical situation is also presented.