title: In vitro blood-perfused bovine liver model: a physiologic model for evaluation of the performance of radiofrequency ablation devices.
abstract: OBJECTIVE
  To describe an in vitro blood-perfused bovine liver model for the testing of radiofrequency (RF) ablation devices and compare the performance of a specific RF ablation device in the model relative to three other biologic models.
  
  
  METHODS
  Fresh bovine livers were used to create three in vitro models: blood-perfused, Krebs-Henseleit (KH) solution-perfused, and nonperfused. The perfused models were connected to a heart-lung machine via the portal vein and perfused with heparinized autologous blood or KH solution under physiologic conditions. Six swine were used as in vivo liver models. A cluster electrode and RF ablation system was operated in impedance mode for 12 minutes in all models. Ablated livers were sectioned, with long- and short-axis measurements of the ablations obtained, and statistical analysis was performed.
  
  
  RESULTS
  A total of 39, 23, 17, and 12 ablations were performed in 14, 6, 5, and 6 blood-perfused bovine livers, KH solution-perfused bovine livers, nonperfused bovine livers, and in vivo porcine livers, respectively. On cut specimens, the average diameters of ablation zones were 4.00 cm (95% CI, 3.88-4.13) in blood-perfused livers, 4.34 cm (95% CI, 4.14-4.50) in KH solution-perfused livers, 4.67 cm (95% CI, 4.50-4.83) in nonperfused livers, and 3.56 cm (95% CI, 3.26-3.83) in in vivo porcine livers. In all models, the ablation zone diameters were normally distributed.
  
  
  CONCLUSIONS
  In the in vitro blood-perfused bovine liver model, the size of ablations produced by an RF ablation device are closer in size to those seen in porcine liver in vivo compared with the lesions produced in KH solution-perfused or nonperfused bovine liver.
authors.affiliation: South Texas Radiology Group, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Orsi
authors.forename: Gerald D
authors.initials: GD
authors.lastname: Dodd
authors.forename: Rex A
authors.initials: RA
authors.lastname: Cardan
authors.forename: Hayden W
authors.initials: HW
authors.lastname: Head
authors.forename: Stephanie K
authors.initials: SK
authors.lastname: Burns
authors.forename: Dana
authors.initials: D
authors.lastname: Blakemore
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Blume
authors.forename: Tyler J
authors.initials: TJ
authors.lastname: Green
mesh_terms: D000818:Animals; D017115:Catheter Ablation / Q000295:instrumentation*; D002417:Cattle; D004867:Equipment Design; D005947:Glucose; D066298:In Vitro Techniques; D008099:Liver / Q000098:blood supply / Q000473:pathology / Q000601:surgery*; D008102:Liver Circulation; D008422:Materials Testing; D023421:Models, Animal; D010477:Perfusion / Q000379:methods*; D013552:Swine; D014325:Tromethamine
chemical_list: C074097:Krebs-Henseleit solution; D014325:Tromethamine; D005947:Glucose