Background and Objective: The role of CT in follow up of hepatocellular carcinoma (HCC) after local ablative therapy have been demonstrated in many clinical experience, whereas the role of contrast enhanced ultrasonography (CEUS) is still under evaluation. The aim of this study is to evaluate the role of immediate CEUS in prediction 30-days CT follow up after single local ablative therapy with radiofrequency ablation (RFA) or percutaneous ethanol injection (PEI). Methods:100 consecutive patients with HCC treated 2006 to 2007 were prospectively included into the study. All the patients were treated with single session of PEI or RFA. After each single percutaneous procedure CEUS was performed in order to identify residual disease (persistence of contrast enhanced pattern). Three different CEUS patters were identified: 1-isovascular-hypervascular pattern, 2-ipovascular pattern, 3-avascular pattern. After 30 days complete necrosis of HCC was evaluated with contrast-enhanced CT scan in all cases. Results: Patients included into the study were submitted to RFA (43 patients) or PEI (57 patients) for HCCs with a mean diameter of 2.7 cm (range 1.5-5 cm). After RFA, isovascular pattern was found in 2% (1/43) of patients resulting in incomplete necrosis at CT; ipovascular pattern was found in 12% (5/43) patients that resulted in incomplete necrosis in 3/5 (60%); in 86% (37/43) avascular pattern was found with complete necrosis at CT in 28/37(76%) cases. Among the PEI group, isovascular pattern was found in 5% (3/57) of patients case resulting incomplete necrosis in 1/3 (33%) case; ipovascular pattern was found in 44% (25/57) of patients that resulted CT incomplete necrosis in 17/25(68%) ; in 19% (11/57) of patients avascular pattern was found with complete necrosis at CT in 2/11(18%) cases. Sensitivity, specificity, positive and negative predictive values for complete necrosis at CT of the CEUS avascular pattern after RFA were 93%, 31%, 76% and 67%,respectively, while the positive predictive value after PEI treatments was 18%.ConclusionsImmediate CEUS control after percutaneous treatment of HCC have high predictive value after RFA where the avascular pattern is highly related with complete necrosis at 30 day CT. On the contrary predictive value of immediate CEUS after PEI is limited