Hepatocellular carcinoma treated with radiofrequency ablation: Comparison of pulse inversion contrast-enhanced harmonic sonography, contrast-enhancedpower Doppler sonography, and helical CT

OBJECTIVE, The purpose of this study was to compare the efficacy of contras t-enhanced pulse inversion harmonic imaging with contrast-enhanced power Do ppler sonography and helical CT to determine incomplete local treatment aft er radiofrequency ablation in patients with hepatocellular carcinoma. MATERIALS AND METHODS. Thirty-five consecutive patients (24 men and II wome n; mean age, 64 years) with 43 hepatocellular carcinomas (3.6 +/- 1.1 cm) w ere treated using internally cooled radiofrequency ablation therapy. Therap eutic response was evaluated at 4 months with dual-phase contrast-enhanced helical CT, conventional power Doppler Sonography, and pulse inversion harm onic imaging using a sonographic contrast agent (SH-508). CT and sonographi c studies were reviewed separately in random order by four radiologists at different consensus conferences. Sensitivity and specificity of the sonogra phic methods were determined using CT as a gold standard and results were c ompared using the McNemar test. RESULTS. CT examinations identified residual tumor in 12 lesions (27.9%). A lthough conventional contrast-enhanced power Doppler sonography identified residual viable tumor foci in four incompletely treated lesions (9.3%), con trast-enhanced pulse inversion harmonic imaging identified residual tumoral enhancement in 10 lesions (23.3%). Thus, the sensitivity of pulse inversio n harmonic imaging (83.3%) was significantly greater (p < 0.05) for detecti ng residual nonablated tumor compared with conventional contrast-enhanced p ower Doppler sonography. CONCLUSION. Our study suggests that contrast-enhanced pulse inversion harmo nic imaging may enable the detection of residual nonablated tumor in more c ases than contrast-enhanced power Doppler sonography and may ultimately pro ve to be a useful adjunct for percutaneous ablation therapies. Nevertheless , contrast-enhanced axial imaging (CT or MR imaging) is currently the most sensitive test for managing thermal ablation for patients with hepatocellul ar carcinoma.