Figure 1a:

(a) Current tumor response classification systems used to report tumor response after treatment. Size-based classification systems include World Health Organization (WHO) criteria (bidimensional) and RECIST (unidimensional), where the size of the treated lesion is measured, regardless of enhancement. Enhancement-based classification systems include EASL (bidimensional), mRECIST (unidimensional), and more recently, LI-RADs (presence or absence of enhancement), where the size of the residual enhancing component is measured for the former two. (b) The LI-RADS treatment response classification system is shown. EASL = European Association for the Study of Liver Diseases, HCC = hepatocellular carcinoma, LI-RAD = Liver Imaging and Reporting Data System, LR-TR = LI-RADS treatment response, mRECIST = modified RECIST, RECIST = Response Evaluation Criteria for Solid Tumors.