BackgroundHepatocellular carcinoma (HCC) is one of the most common tumors worldwide. Extrahepatic metastasis from HCC occurs in one third of patients with most common sites being the lungs, lymph nodes, bone, and adrenal glands. Various conventional imaging modalities like ultrasonography, computed tomography, magnetic resonance imaging, and bone scan are used in the diagnosis and staging of HCC. Recently, PET performed with fluoro-2-deoxy-d-glucose (FDG) has proved valuable in providing important tumor-related qualitative and quantitative metabolic information that is critical to the diagnosis and staging of the disease. This article aims to show the role of 18F-FDG PET-CT in the initial staging of HCC and its impact on changing clinical decision.Main textWe discussed the previous studies on the ability of 18F-FDG PET-CT to detect HCC, vascular invasion, regional and distant metastasis. We also studied the relation between the histopathologic grading of HCC and its detectability by 18F-FDG PET-CT.Conclusions18F-FDG PET-CT has proved valuable in HCC staging and has a great impact on the clinical decision for HCC treatment.