Imaging-based diagnosis of hepatocellular carcinoma: Liver Imaging Reporting and Data System and beyond

Hepatocellular carcinoma (HCC) is currently the third leading cause of cancer-related death globally. It is unique among other cancers in the sense that imaging-based diagnosis is accepted as a definite diagnosis among at-risk patients by all major guidelines. The classic imaging finding of HCC on multiphasic contrast-enhanced CT and MRI is hyperenhancement during the arterial phase with hypoenhancement ("washout") and enhancing capsule in the portal venous and/or delayed phases. When distinct imaging features of HCC are applied in patients with high pre-test probability of HCC, they result in high specificity for diagnosis of this entity. There are several imaging-based diagnostic algorithms developed by different societies, all aimed at high specificity and reasonable sensitivity for noninvasive diagnosis of HCC in at-risk population. These guidelines differ in their clinical scope, diagnostic algorithm, intended users, complexity level, and technical requirements as well as their clinical and socioeconomic contexts. The differences between these guidelines and nuances in imaging of HCC are discussed in this review article. Lastly, the role of imaging beyond the lesion characterization and upcoming advancements in this field are discussed.