The emerging role of positron emission tomography in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is a leading cause of cancer mortality worldwide. HCC a heterogeneous disease occurring on the background of cirrhosis. The presence of cirrhosis limits the sensitivity of conventional imaging modalities in differentiating HCC from surrounding cirrhotic parenchyma. Positron emission tomography (PET) using 18F-fluorodeoxyglucose (18F-FDG) is widely used for assessing a variety of malignancies, however, has poor sensitivity in the evaluation of HCC. This has led to the investigation of other radiotracers such as 11C-acetate and 11C-choline, with improved sensitivity in terms of detection and therapeutic response. In this review, we discuss the emerging field of PET imaging for the detection, staging and assessment of treatment response in HCC. In particular we discuss the role of 18F-FDG-PET in imaging hepatocellular cancer, the limitations of this PET tracer and emerging novel PET tracers being investigated that exploit key metabolic processes including fatty acid and lipid synthesis, choline kinase activity and gene expression.