Background and purpose: The incidence of liver cancer is high in China. Primary liver cancers usually occur in patients with liver cirrhosis

which is a challenge for the early diagnosis of liver cancer. Our purpose is to investigate the efficacy of contrast-enhanced ultrasonography (CEUS) in the early identification and diagnosis of small hepatocellular carcinoma (HCC) by regularly tracking and supervising the high risk population. Methods: A total of 320 high risk patients of HCC admitted in our hospital from February 2011 to November 2013 were enrolled in this prospective study. All patients underwent conventional ultrasound and hepatic CEUS. The differential diagnosis of malignant HCCs from benign ones was based on the enhancement patterns of hepatic lesions in different phases on CEUS. Results: Twenty patients were diagnosed as small HCC among 320 HCC high risk patients who were under regular surveillance using CEUS and all were pathologically confirmed. Seven of the 20 HCC cases were smaller than 1.0 cm and 13 measured 1.1-2.0 cm. There were 6 (30.0%) HCCs presented as “early wash-in and slow wash-out” atypical pattern of HCC. The small size of the lesion and iso-echogenicity were the main factors of atypical pattern of HCC on CEUS.Conclusion: Ultrasonography and CEUS surveillance is a useful strategy for the early detection of small HCCs in high risk patients

which can help them to receive proper therapeutic management in time.