title: Hepatic vascular inflow occlusion enhances tissue destruction during cryoablation of porcine liver.
abstract: BACKGROUND
  Local recurrences after cryoablation of liver tumors have been reported at rates from 5% to 44% and can be caused by inadequate coverage of the tumor by the frozen region. Hepatic vascular inflow occlusion may facilitate ablation by enlarging the size of the frozen region and the tissue necrosis induced by freezing. Few studies have documented these effects of inflow occlusion during liver cryoablation.
  
  
  METHODS
  Two cryolesions were induced in the liver of 12 pigs in a standardized set-up. Vascular inflow occlusion was used in six pigs during freezing. Two freeze cycles were performed at each location. Ice-ball volume was estimated by intraoperative magnetic resonance imaging. Cryolesion volume was estimated from histopathologic examination of the lesions 4 days after ablation.
  
  
  RESULTS
  The median volume of ice-balls produced during inflow occlusion was 107% larger than for ice-balls produced without occlusion (P < 0.001). The median volume of cryolesions made during inflow occlusion was 195% larger than for cryolesions induced without occlusion (P < 0.001). The geometry of the ice-balls was more regular if produced during inflow occlusion than if not. The ice-balls produced during the second freeze cycle were 17% and 20% larger than the ice-ball produced during the first freeze for lesions made with (P = 0.01) and without (P = 0.03) inflow occlusion.
  
  
  CONCLUSIONS
  Hepatic vascular inflow occlusion enables freezing of larger volumes of liver tissue andincreases the volume of tissue necrosis induced during cryoablation of porcine liver.
authors.affiliation: Interventional Centre and Surgical Department, Rikshospitalet, Oslo, Norway. tom.mala@rikshospitalet.no
authors.forename: Tom
authors.initials: T
authors.lastname: Mala
authors.forename: Lars
authors.initials: L
authors.lastname: Frich
authors.forename: Lars
authors.initials: L
authors.lastname: Aurdal
authors.forename: Ole P
authors.initials: OP
authors.lastname: Clausen
authors.forename: Bjørn
authors.initials: B
authors.lastname: Edwin
authors.forename: Odd
authors.initials: O
authors.lastname: Søreide
authors.forename: Ivar P
authors.initials: IP
authors.lastname: Gladhaug
mesh_terms: D000818:Animals; D003452:Cryosurgery / Q000009:adverse effects*; D007053:Ice; D008099:Liver / Q000098:blood supply / Q000473:pathology* / Q000601:surgery*; D008102:Liver Circulation; D008279:Magnetic Resonance Imaging; D009336:Necrosis; D013552:Swine
chemical_list: D007053:Ice