Ultrasonography in surveillance for hepatocellular carcinoma in patients with non-alcoholic fatty liver disease

International guidelines recommend six monthly ultrasounds as the primary surveillance tool for patients at risk of hepatocellular carcinoma (HCC). The dominant driver of liver disease in HCC surveillance populations is shifting, particularly in Europe and the United States, from chronic viral hepatitis (B or C), towards non-alcoholic fatty liver disease (NAFLD). Today, the population requiring HCC surveillance is also characterised by a high prevalence of overweight/obesity. These patient characteristics significantly impair ultrasound quality which can impede the detection of early HCC lesions. This diagnostic limitation has significant implications considering that eligibility for curative treatment depends upon the stage at which the cancer is detected. In this narrative review, we provide a comprehensive overview of the published evidence and national/international guidelines regarding ultrasound surveillance for HCC in people with NAFLD. We examine ultrasound sensitivity in this cohort for the detection of all stage and early HCC, the impact of steatosis and abdominal obesity on ultrasound performance, evidence for the addition of serum alpha-fetoprotein measurement, optimal timing of surveillance, emerging modalities for risk stratification and screening, and outline the challenges of case finding and surveillance eligibility criteria in this patient cohort. Finally, amalgamating all available evidence, we propose a pragmatic surveillance pathway for patients with NAFLD.