A Comparison of Biannual Two-Phase Low-Dose Liver CT and US for HCC Surveillance in a Group at High Risk of HCC Development

Background and Aims: Biannual ultrasonography (US) is a current recommendation for hepatocellular carcinoma (HCC) surveillance in a high-risk group. The sensitivity of US, however, has been low in patients with a high risk of developing HCC. We aimed to compare sensitivity for HCC of biannual US and two-phase low-dose computed tomography (LDCT) in patients with a high risk of HCC. Methods: In this prospective single-arm study, participants with an annual risk of HCC greater than 5% (based on a risk index of ≥2.33) and who did not have a history of HCC were enrolled from November 2014 to July 2016. Participants underwent paired biannual US and two-phase LDCT 1–3 times. Two-phase LDCT included arterial and 3-min delayed phases. The sensitivity, specificity, and positive predictive value of HCC detection using US and two-phase LDCT were compared using a composite algorithm as a standard of reference. Results: Of the 139 enrolled participants, 137 underwent both the biannual US and two-phase LDCT at least once and had follow-up images. Among them, 27 cases of HCC (mean size: 14 ± 4 mm) developed in 24 participants over 1.5 years. Two-phase LDCT showed a significantly higher sensitivity (83.3% [20/24] vs. 29.2% [7/24], p < 0.001) and specificity (95.6% [108/113] vs. 87.7% [99/113], p =0.03) than US. A false-positive result was reported in 14 participants at US and 5 participants at two-phase LDCT, resulting in a significantly higher positive predictive value of two-phase LDCT (33.3% [7/21] vs. 80% [20/25], p < 0.001). Conclusions: Patients with a risk index ≥2.33 showed a high annual incidence of HCC development in our study, and two-phase LDCT showed significantly higher sensitivity and specificity for HCC detection than US.