Evaluation of Posttreatment Response of Hepatocellular Carcinoma with Contrast-enhanced Coded Phase-Inversion Harmonic US: Comparison with Dynamic CT

Abstract

PURPOSE: To assess the reliability of contrast material–enhanced real-time gray-scale ultrasonography (US) in evaluating posttreatment response of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Fifty HCC nodules were examined with contrast-enhanced coded phase-inversion harmonic US before and after treatment. Intratumoral vascularity was assessed with continuous imaging in the early arterial phase and with interval-delay scanning to depict tumor parenchymal flow during the blood pool phase. Vascular findings at US were compared with those at dynamic computed tomography (CT). RESULTS: In 50 HCC nodules before treatment, positive enhancement of tumor vessels and tumor parenchymal flow (stain) were observed in 47 (94%) and 46 (92%), respectively. Either tumor vessel or stain was visualized with coded harmonic US in 49 of 50 nodules. Eighty-one coded harmonic US studies were performed in 49 posttreatment HCC nodules. Compared with dynamic CT, the sensitivity, specificity, and accuracy of coded harmonic US in helping to detect positive enhancement in pretreatment HCC were 98% (49 of 50), 100% (50 of 50), and 98% (49 of 50), respectively. After treatment, positive enhancement of tumor vascularity was observed in 39 (48%) of 81 posttreatment studies, and no enhancement was observed in others (52%). Coded harmonic US demonstrated partial and no enhancement of tumor vascularity in four and one nodule, respectively; after transcatheter arterial embolization with iodized oil, evaluation of tumor vascularity with dynamic CT was difficult because of the presence of oil. CONCLUSION: With enhancement, coded harmonic US depicted tumor vascularity by showing tumor vessels in a real-time fashion at continuous imaging and tumor parenchymal flow at interval-delay scanning.