Imaging techniques for the diagnosis of hepatocellular carcinoma and the evaluation of response to treatment.

ABSTRACT

Imaging plays a critical role in the diagnosis of hepatocellular carcinoma (HCC). In the USA, non-invasive imaging based diagnosis of HCC has largely replaced biopsy because of the high specificity and positive predictive value of imaging features for HCC. Because of the important role of imaging and the need to promote standardization of the management of HCC, several imaging-based algorithms for the diagnosis of HCC in at-risk patients have been developed.Imaging also plays a vital role in the assessment of HCC response to locoregional therapies (LRT) such as ablative and endovascular therapies. Standard imaging response criteria of solid tumors that rely solely on change in tumor size for determination of therapeutic success are not applicable to HCC undergoing LRT. Therefore, several systems have been developed over the years to objectively evaluate HCC response to LRT.In this review, we will describe major and ancillary imaging features of HCC, how these features are incorporated into the various imaging based algorithms, discuss the differences between algorithms, and address the emerging role of new imaging techniques and contrast agents in the diagnosis of HCC. We will also discuss the importance of assessment of HCC response to LRT, describe patterns of imaging response to the various therapies including newer volumetric and functional response measures, and examine and compare proposed response criteria of HCC to LRT.