Purpose: This study evaluated the effectiveness of contrast-enhanced ultrasound (CEUS), performed immediately after percutaneous ethanol injection (PEI) 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 RFTA (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 RFTA, respectively. A statistically significant difference (p<0.05) between the sensitivity of CEUS after PEI and after RFTA 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.