title: Radiofrequency ablation of the liver: extended effect of transcatheter arterial embolization with iodized oil and gelatin sponge on histopathologic changes during follow-up in a pig model.
abstract: OBJECTIVE
  To assess the extended effects of transcatheter arterial embolization with iodized oil and gelatin sponge on liver histopathologic changes in radiofrequency (RF)-ablated zones and the surrounding liver parenchyma in a pig model.
  
  
  METHODS
  Eighteen consecutive pigs subjected to 36 RF applications performed immediately after segmental embolization with iodized oil and gelatin sponge to the left lobe of the liver (embolization/RF ablation) were euthanized immediately after the procedure or 1 or 4 weeks later. The right lobes were used as controls for RF applications without embolization. The ablated zones and the surrounding liver parenchyma were measured and examined histopathologically.
  
  
  RESULTS
  The average maximum ablated zone was significantly larger in the embolization/RF ablation specimens than in the RF ablation-alone specimens at all three follow-up time points. Ten of the 12 specimens obtained immediately after embolization/RF ablation showed wide hemorrhagic areas spreading to the periphery of the liver and microscopically showed marked intralobular congestion with sinusoidal dilation. This hemorrhagic change had disappeared in all the specimens obtained 1 week after embolization/RF ablation, but 10 of the 12 specimens showed wedge-shaped areas of segmental degenerative parenchyma beginning at the ablated zone and extending to the periphery of the liver; these were microscopically revealed to be areas of coagulative necrosis, indicating hepatic infarction. The sizes of these necrotic zones had decreased at 4 weeks after embolization/RF ablation.
  
  
  CONCLUSIONS
  RF ablation performed immediately after embolization in normal pig liver induced large ablated zones accompanied by wedge-shaped areas of segmental infarction.
authors.affiliation: Gastroenterological Center, Yokohama City University Medical Center, Minami-ku, Yokohama, Japan. morimoto@urahp.yokohama-cu.ac.jp
authors.forename: Manabu
authors.initials: M
authors.lastname: Morimoto
authors.forename: Kazushi
authors.initials: K
authors.lastname: Numata
authors.forename: Akinori
authors.initials: A
authors.lastname: Nozawa
authors.forename: Masaaki
authors.initials: M
authors.lastname: Kondo
authors.forename: Akito
authors.initials: A
authors.lastname: Nozaki
authors.forename: Masayuki
authors.initials: M
authors.lastname: Nakano
authors.forename: Katsuaki
authors.initials: K
authors.lastname: Tanaka
mesh_terms: D000818:Animals; D001777:Blood Coagulation; D017115:Catheter Ablation; D004621:Embolization, Therapeutic / Q000379:methods*; D005260:Female; D005781:Gelatin Sponge, Absorbable / Q000008:administration & dosage*; D007459:Iodized Oil / Q000008:administration & dosage*; D008099:Liver / Q000098:blood supply / Q000473:pathology / Q000601:surgery*; D023421:Models, Animal; D009336:Necrosis; D034421:Sus scrofa; D013997:Time Factors
chemical_list: D007459:Iodized Oil