title: Outcomes of patients with hepatocellular carcinoma referred for percutaneous radiofrequency ablation at a tertiary center: analysis focused on the feasibility with the use of ultrasonography guidance.
abstract: OBJECTIVE
  This study aimed to assess the feasibility of performing ultrasonography (US)-guided percutaneous radiofrequency (RF) ablation on patients with hepatocellular carcinoma (HCC) and identify causes of procedure infeasibility and its predisposing conditions.
  
  
  METHODS
  A total of 109 consecutive patients (male:female=86:23; mean 59.9 years) with 136 HCCs (mean 1.8 cm) who had been referred for planning US were analyzed. We evaluated overall procedure feasibility as well as specific factors relating to feasibility, including inability to visualize the tumor with US and factors relating to safety of the procedure.
  
  
  RESULTS
  The use of percutaneous RF ablation was concluded as infeasible for 45 tumors (33.1%). Reasons for infeasibility included tumor invisibility (n=32), a high risk of collateral thermal injury (n=5), absence of a safe electrode path (n=5) and a combination of factors (n=3). Among 136 tumors, 36(26.5%) were invisible due to isoechogenicity (n=16), indiscrimination from surrounding cirrhotic nodules (n=10) or an unfavorable location (n=10). Tumor invisibility was significantly attributed to a small tumor size (P<0.001, risk ratio=0.823) and the presence of macronodular cirrhosis (P=0.006, risk ratio=4.117). Seven patients with invisible tumors were treated with RF ablation after follow-up (n=4) or with use of adjacent structures as landmarks (n=3). Ultimately, 65 of 109 patients were treated with percutaneous RF ablation.
  
  
  CONCLUSIONS
  US-guided percutaneous RF ablation for HCC was feasible in about two-thirds of candidates. Infeasibility was mostly due to inability to visualize the tumor with US, especially for patients with smaller tumor and macronodular cirrhosis.
authors.affiliation: Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50, Irwon-dong, Gangnam-gu, Seoul 135-710, Republic of Korea.
authors.forename: Ji-Eun
authors.initials: JE
authors.lastname: Kim
authors.forename: Young-Sun
authors.initials: YS
authors.lastname: Kim
authors.forename: Hyunchul
authors.initials: H
authors.lastname: Rhim
authors.forename: Hyo K
authors.initials: HK
authors.lastname: Lim
authors.forename: Min Woo
authors.initials: MW
authors.lastname: Lee
authors.forename: Dongil
authors.initials: D
authors.lastname: Choi
authors.forename: Sung Wook
authors.initials: SW
authors.lastname: Shin
authors.forename: Sung Ki
authors.initials: SK
authors.lastname: Cho
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001707:Biopsy, Needle; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D003287:Contrast Media; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007472:Iohexol / Q000031:analogs & derivatives; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D016015:Logistic Models; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide