Contrast-enhanced ultrasonography (CEUS) immediately after percutaneous ablation of hepatocellular carcinoma

Purpose. This study evaluated the effectiveness of contrast-enhanced ultrasound (CEUS), performed immediately after percutaneous ethanol injection (PET) or radiofrequency thermal ablation (RFTA), by comparing results with the computed tomography (CT) follow-up. Materials and methods. Sixty-nine consecutive patients with a diagnosis of hepatocellular carcinoma (HCC) were included in this prospective study. All patients underwent PEI or RFTA. After treatment, three CEUS enhancement patterns were observed: isovascular, hypovascular and avascular, which were compared with the CT findings. Sensitivity of the avascular pattern at CEUS and effectiveness of the ablative procedures were evaluated and compared with the chi-square test. Results. Ninety hypervascular HCCs, with a mean diameter of 2.6 cm (0.5-4.9 cm), underwent PEI (n=54) and RIFTA (n=36). In the first group, CT identified complete necrosis in 28/54 (52%) lesions, 21 (75%) of which had avascular, one (4%) isovascular and six (21%) hypovascular patterns at CEUS. In the second group, CT showed complete necrosis in 31/36 (86%) lesions, all (100%) of which had a corresponding avascular pattern at CEUS. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of the avascular pattern at CEUS compared with CT findings were 75%, 69%, 72%, 72% and 72% for PEI and 100%, 20%, 89%, 100% and 89%, for RFFA, respectively. A statistically significant difference (p<0.05) between the sensitivity of CEUS after PEI and after RIFTA and between the necrosis obtained by RFTA and PEI were observed. Conclusions. CEUS performed immediately after percutaneous ablation of hepatocellular carcinoma to evaluate treatment efficacy is compulsory in the case of RFTA but not for PEI.