title: Effect of Change in Portal Venous Blood Flow Rates on the Performance of a 2.45-GHz Microwave Ablation Device.
abstract: OBJECTIVE
  To investigate the effect of change in portal venous blood flow rates on the size and shape of ablations created by a 2.45-GHz microwave ablation device.
  
  
  METHODS
  This study was exempt from review by the institutional animal care and use committee. An in vitro bovine liver model perfused with autologous blood via the portal vein at five flow rates (60, 70, 80, 90, and 100 mL/min per 100 g of liver) was used to evaluate the effect of change in flow rates on the size and shape of coagulation created by a 2.45-GHz, 140-W microwave ablation device operated for 5 and 10 minutes. Three ablations per ablation time were conducted in each of 10 livers, with two livers perfused at each flow rate. Short- and long-axis diameters were measured from gross specimens, and volume and sphericity index were calculated. General linear mixed models that accounted for correlations within the liver were used to evaluate the effects of lobe, flow, and ablation time on size and sphericity index of ablations.
  
  
  RESULTS
  Flow did not have a significant effect on the size or shape of coagulation created at 5 or 10 minutes (P > .05 for all tests). The mean short- and long-axis diameters and volume were 3.2 cm (95% confidence interval [CI]: 3.1, 3.3), 5.6 cm (95% CI: 5.4, 5.8), and 30.2 cm(3) (95% CI: 28.4, 32.1) for the 5-minute ablations and 3.8 cm (95% CI: 3.7, 3.9), 6.5 cm (95% CI: 6.3, 6.7), and 49.3 cm(3) (95% CI: 47.5, 51.2), for the 10-minute ablations, respectively. The mean sphericity index for both 5- and 10-minute ablations was 34.4% (95% CI: 32%, 36.7%).
  
  
  CONCLUSIONS
  Change in portal venous blood flow rates did not have an effect on the size and shape of ablations created by a 2.45-GHz microwave ablation device.
authors.affiliation: From the Department of Radiology, School of Medicine (G.D.D., S.M.K., A.C.L.), and School of Public Health (D.H.G.), University of Colorado, 12401 E 17th Ave, Mail Stop L954, PO Box 6510, Aurora, CO 80045.
authors.forename: Gerald D
authors.initials: GD
authors.lastname: Dodd
authors.affiliation: From the Department of Radiology, School of Medicine (G.D.D., S.M.K., A.C.L.), and School of Public Health (D.H.G.), University of Colorado, 12401 E 17th Ave, Mail Stop L954, PO Box 6510, Aurora, CO 80045.
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Kreidler
authors.affiliation: From the Department of Radiology, School of Medicine (G.D.D., S.M.K., A.C.L.), and School of Public Health (D.H.G.), University of Colorado, 12401 E 17th Ave, Mail Stop L954, PO Box 6510, Aurora, CO 80045.
authors.forename: Anthony C
authors.initials: AC
authors.lastname: Lanctot
authors.affiliation: From the Department of Radiology, School of Medicine (G.D.D., S.M.K., A.C.L.), and School of Public Health (D.H.G.), University of Colorado, 12401 E 17th Ave, Mail Stop L954, PO Box 6510, Aurora, CO 80045.
authors.forename: Deborah H
authors.initials: DH
authors.lastname: Glueck
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity; D017115:Catheter Ablation / Q000295:instrumentation / Q000379:methods*; D002417:Cattle; D066298:In Vitro Techniques; D008099:Liver / Q000098:blood supply; D008872:Microwaves / Q000627:therapeutic use*; D011169:Portal Vein / Q000502:physiology*