Radiological Diagnosis and Characterization of HCC

Imaging plays a central role in hepatocellular carcinoma (HCC) screening/surveillance, diagnosis, staging, and treatment response assessment. Clinical imaging methods include abdominal ultrasound (US) used mostly for HCC screening/surveillance and imaging-guided biopsies, computed tomography (CT), and magnetic resonance imaging (MRI) used for confident diagnosis of typical HCC tumors without histologic confirmation, according to practice guidelines. Qualitative HCC imaging appearance is closely linked to its vascular characteristics, with typical imaging features such as hyperenhancement during the arterial phase relative to the surrounding liver parenchyma and washout in portal venous or delayed venous phases post-contrast on CT and MRI. There is recent growing interest in assessing tissue properties using quantitative imaging. Several quantitative imaging methods have been developed with the common goal of improved tumor characterization and prediction of aggressiveness in order to achieve precise and personalized management of HCC. New techniques, such as radiomics, have been proposed as surrogate for histologic examination, avoiding tissue sampling risks and allowing repetitive measurements of the entire tumor volume. Furthermore, with the emergence of molecular targeted therapy, noninvasive imaging techniques allowing early assessment of therapeutic efficacy are necessary.