Clinical translation in the treatment of hepatocellular carcinoma following the introduction of contrast-enhanced ultrasonography with Sonazoid

Some hepatocellular carcinoma (HCC) nodules are detectable with dynamic computed tomography, but not by conventional B-mode ultrasonography (US). Contrast-enhanced US (CEUS) with Sonazoid, a new injectable contrast agent, has been used in Japan since January 2007. The primary advantage of this agent is the ability to maintain observations continuously in the Kupffer phase. We assessed the clinical role of CEUS with Sonazoid for radiofrequency ablation (RFA). From January 2005 to December 2008, 1142 patients were treated with surgical resection, RFA, percutaneous ethanol injection or transcatheter arterial chemoembolization, following the exclusion of those patients treated with chemotherapy or supportive care. The patients included in the study were divided into the pre-CEUS (n=451, 2005 and 2006) and post-CEUS (n=691, 2007 and 2008) groups. Clinical background (e.g., etiology, Child-Pugh classification, tumor node metastasis stage, percentage of patients matched with Milan criteria and selected therapies) was compared between the two groups. In addition, naive cases were compared between the groups. There were 130 naive HCC cases in the pre-CEUS group and 171 in the post-CEUS group. Although there were no significant differences for clinical background, the percentage of RFA cases increased from 21 (n=95) to 32% (n=219) and from 32 (n=41) to 52% (n=89) for total and naive subjects, respectively, after CEUS was introduced (P<0.01). In naive cases treated with RFA, tumor numbers in the post-CEUS group were larger than those of the pre-CEUS group (1.15±0.48 vs. 1.40±0.67; P<0.01). CEUS with Sonazoid, therefore, makes it possible to perform RFA in a considerable number of HCC cases that would otherwise be invisible by conventional B-mode US.