Characterization of 1-to 2-cm Liver Nodules Detected on HCC Surveillance Ultrasound According to the Criteria of the American Association for the Study of Liver Disease: Is Quadriphasic CT Necessary?

OBJECTIVE. The purpose of this study was to identify the essential number of phases from multiphasic CT for 1- to 2-cm hepatocellular carcinoma (HCC) on surveillance ultrasound and to compare the results with the American Association for the Study of Liver Disease (AASLD) standard (arterial phase hypervascularity and portal venous phase [PVP] or delayed phase hypovascularity). MATERIALS AND METHODS. The study included 110 newly detected nodules (1–2 cm; 36 HCC, 74 benign) in 96 patients detected in an HCC surveillance program. Three radiologists prospectively evaluated the attenuation of each nodule relative to the liver on each phase of quadriphasic CT. Univariate and multivariate logistic regression analyses were used to identify parameters associated with HCC. Multiple combinations of phases were compared with the AASLD standard. RESULTS. Only arterial phase hypervascularity and delayed phase hypovascularity were significantly associated with HCC both on univariate (odds ratio, arterial phase 7.51 [95%...