title: Planning sonography to assess the feasibility of percutaneous radiofrequency ablation of hepatocellular carcinomas.
abstract: OBJECTIVE
  The objective of our study was to evaluate the feasibility rate and the reasons for infeasibility of percutaneous radiofrequency ablation of hepatocellular carcinomas (HCCs) at planning sonography.
  
  
  METHODS
  We retrospectively evaluated 248 patients who had been referred for planning sonography at our department between October 2005 and February 2006. We reviewed the radiologic reports of 256 planning sonography examinations in terms of the rate of feasible cases and the reasons for infeasibility. The reasons for infeasibility were classified in six categories: an inconspicuous tumor, an inadequate electrode path, an organ vulnerable to collateral thermal damage, a tumor that was too large or too many tumors, and a high risk of the heat sink effect. In addition, we assessed the treatment modality for the patients who were determined to have HCCs for which percutaneous radiofrequency ablation was not feasible.
  
  
  RESULTS
  In 141 (55%) of the 256 planning sonography examinations, percutaneous radiofrequency ablation was feasible. The remaining 115 (45%) planning sonography examinations revealed that radiofrequency ablation was not a feasible procedure. The reasons for infeasibility included an inconspicuous tumor in 77 patients (55.8%), an inadequate electrode path in 33 patients (23.9%), an organ vulnerable to collateral thermal damage in 14 patients (10.1%), a tumor that was too large or too many tumors in eight patients (5.8%), a high risk of the heat sink effect in five patients (3.6%), and a portal vein thrombosis in one patient (0.7%). One reason for infeasibility was found in 96 patients, two reasons in 19 patients, and four reasons in one patient. Seventy (61.9%) of 113 patients for whom radiofrequency ablation was not feasible underwent transcatheter arterial chemoembolization as an alternative treatment.
  
  
  CONCLUSIONS
  In approximately half of the patients for whom percutaneous radiofrequency ablation of HCC is requested, the procedure is not feasible, mainly due to inconspicuous tumors, at planning sonography. Additional objective criteria for assessing the feasibility of radiofrequency ablation and therapeutic strategies according to the reasons for infeasibility should be investigated further.
authors.affiliation: Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50, Ilwon-dong, Kangnam-ku, Seoul 135-710, Korea. rhimhc@skku.edu
authors.forename: Hyunchul
authors.initials: H
authors.lastname: Rhim
authors.forename: Mi Hee
authors.initials: MH
authors.lastname: Lee
authors.forename: Young-Sun
authors.initials: YS
authors.lastname: Kim
authors.forename: Dongil
authors.initials: D
authors.lastname: Choi
authors.forename: Won Jae
authors.initials: WJ
authors.lastname: Lee
authors.forename: Hyo K
authors.initials: HK
authors.lastname: Lim
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging* / Q000601:surgery*; D017115:Catheter Ablation; D015331:Cohort Studies; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D012189:Retrospective Studies; D025321:Surgery, Computer-Assisted; D014463:Ultrasonography