title: Real-time US-CT/MR fusion imaging for percutaneous radiofrequency ablation of hepatocellular carcinoma.
abstract: Although ultrasonography (US) guided radiofrequency ablation (RFA) is a commonly used treatment option for early hepatocellular carcinoma (HCC), inconspicuous tumors on US limits its feasibility. Thus, we prospectively determined whether real-time US-CT/MR fusion imaging can improve the technical feasibility of RFA compared with B-mode US, and help predict local tumor progression after RFA in patients with HCC.
  
  
  
  A total of 216 patients with 243 HCCs ⩽5cm referred for RFA were prospectively enrolled. Prior to RFA, the operators scored the visibility of tumors, and technical feasibility on a 4-point scale at both B-mode US and fusion imaging. RFA was performed with a switching monopolar system using a separable cluster electrode under fusion imaging guidance. Technique effectiveness, local tumor progression and intrahepatic remote recurrences were evaluated.
  
  
  
  Tumor visibility and technical feasibility were significantly improved with fusion imaging compared with B-mode US (p<0.001). Under fusion imaging guidance, the technique effectiveness of RFA for invisible tumors on B-mode US was similar to those for visible tumors (96.1% vs. 97.6%, p=0.295). Estimated cumulative incidence of local tumor progression at 24months was 4.7%, and previous treatment for other hepatic tumors (p=0.01), higher expected number of electrode insertions needed and lower technical feasibility scores (p<0.01) on fusion imaging were significant negative predictive factors for local tumor progression.
  
  
  
  Real-time fusion imaging guidance significantly improved the tumor visibility and technical feasibility of RFA in patients with HCCs compared with B-mode US, and low feasibility scores on fusion imaging was a significant negative predictive factor for local tumor progression.
  
  
  
  US/CT-MR fusion imaging guidance improved the tumor visibility and technical feasibility of RFA in patients with HCCs. In addition, fusion imaging guided RFA using multiple electrodes demonstrated a high technique effectiveness rate and a low local tumor progression rate during mid-term follow-up. Clinical trial number: ClinicalTrials.gov number, NCT02687113.
authors.affiliation: Department of Radiology, Seoul National University Hospital, Seoul, South Korea.
authors.forename: Su Joa
authors.initials: SJ
authors.lastname: Ahn
authors.affiliation: Department of Radiology, Seoul National University Hospital, Seoul, South Korea; Institute of Radiation Medicine, Department of Internal, Seoul National University Hospital, Seoul, South Korea. Electronic address: jmsh@snu.ac.kr.
authors.forename: Jeong Min
authors.initials: JM
authors.lastname: Lee
authors.affiliation: Department of Radiology, Seoul National University Hospital, Seoul, South Korea.
authors.forename: Dong Ho
authors.initials: DH
authors.lastname: Lee
authors.affiliation: Department of Radiology, Seoul National University Hospital, Seoul, South Korea.
authors.forename: Sang Min
authors.initials: SM
authors.lastname: Lee
authors.affiliation: Department of internal medicine, Seoul National University Hospital, Seoul, South Korea.
authors.forename: Jung-Hwan
authors.initials: JH
authors.lastname: Yoon
authors.affiliation: Department of internal medicine, Seoul National University Hospital, Seoul, South Korea.
authors.forename: Yoon Jun
authors.initials: YJ
authors.lastname: Kim
authors.affiliation: Department of internal medicine, Seoul National University Hospital, Seoul, South Korea.
authors.forename: Jeong-Hoon
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of internal medicine, Seoul National University Hospital, Seoul, South Korea.
authors.forename: Su Jong
authors.initials: SJ
authors.lastname: Yu
authors.affiliation: Department of Radiology, Seoul National University Hospital, Seoul, South Korea; Institute of Radiation Medicine, Department of Internal, Seoul National University Hospital, Seoul, South Korea.
authors.forename: Joon Koo
authors.initials: JK
authors.lastname: Han
mesh_terms: D000328:Adult; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000473:pathology / Q000601:surgery; D017115:Catheter Ablation / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000473:pathology / Q000601:surgery; D053783:Magnetic Resonance Imaging, Interventional / Q000379:methods; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods*; D056910:Republic of Korea; D025321:Surgery, Computer-Assisted / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods; D018084:Ultrasonography, Interventional / Q000379:methods
keywords: Hepatocellular carcinoma; Imaging guidance; Local tumor progression; Radiofrequency ablation; Real-time fusion imaging; Risk of recurrence