To prospectively evaluate the technical success rate of real-time computed tomography/CT/magnetic resonance imagingMR and -ultrasound (CT/MRI-US) automatic fusion system and the long-term therapeutic efficacy of radiofrequency ablation (RFA) guided by automatic fusion in hepatocellular carcinoma (HCC) patients.

RFA is one of commonly used local therapies for primary or secondary liver tumors. For successful and safe procedure, safe route of electrode and lesion visibility are essential for RFA, and the conditions are usually evaluated on pre-RFA planning ultrasonography (USG). However, RFA is sometimes aborted due to limited sonic window of various cause and challenging identification of small isoechoic tumors or hepatocellular carcinomas among dysplastic nodules . Therefore, precise targeting and assuring safe route would be of clinical importance. In this preliminary study, investigators attempted to determine automatic US and CT/MR fusion technique would be able to improve RFA feasibility in patients with liver tumors.

Inclusion Criteria:

• Pathologic or typical imaging based diagnosis of HCC
• Multiphase CT or MRI within 3 months ahead of procedure
• No evidence of distant metastasis
• No contraindications for conventional RFA procedure in our institute, which are uncontrolled coagulopathy (international standard ratio ≥ 1.6, or platelet > 50,000), poor cooperation, unfeasible for sedation, portal vein tumor thrombus, tumor number >4, largest tumor size > 5cm, and tumors abutting portal vein or bile ducts bigger than segmental branches.

Exclusion Criteria:

• Lack of multiphase CT or MRI withing 3 months ahead of procedure
• RFA planned for palliative purpose
• Diagnosed as non-HCC malignancy
• Right hepatectomy state