To evaluate the clinical value of real-time virtual sonography navigation in radiofrequency ablation(RFA) of hepatocellular carcinoma (HCC) invisible in B-mode ultrasound.

Sixty-two HCC lesions in 54 patients in the Third Affiliated Hospital of Sun Yat-sen University from October 2010 to March 2012, diagnosed by computed tomography (CT) or magnetic resonance imaging (MRI) but invisible in B-mode ultrasound, were studied prespectively. Local ethical committee approval had been received and that the informed concent of all participating subjects was obtained. Fifty-four patients underwent RFA, guided by real-time virtual sonography navigation. The image fusion of ultrasound and CT or MRI and the position match time was observed and successful fusion rate was calculated. Complications such as bleeding, ascites and pleural effusion and death were observed during and after RFA. All the patients received CT or MRI and serum alpha-fetoprotein (AFP) test at one month after RFA to check whether the HCC lesions had been completely ablated.

The image fusion was successfully performed in all the 62 lesions with successful rate of 100% (62/62). The average time spent on image fusion was 7.5 minutes (5 to 20 minutes). One patient complained of chest tightness due to heavy hemothorax. Catheter was applied for drainage and removed 4 days later after ultrasound revealed no fluid in the chest cavity. Fourteen patients had asymptomatic pleural effusion or ascites 2 days after ablation which disappeared in 1 to 2 weeks. RFA related death was not found. And CT or MRI one month after RFA showed that all the other 58 HCC lesions had been completely ablated with a 100% ablation rate. AFP declined below 20 μg/L in the 10 patients whose AFP raised before RFA.

The real-time virtual sonography navigation can be applied in the RFA of HCC which is invisible in B-mode ultrasound. It can be a safe and effective supplementary for RFA.