title: The prediction of radiofrequency ablation zone volume using vascular indices of 3-dimensional volumetric colour Doppler ultrasound in an in vitro blood-perfused bovine liver model.
abstract: OBJECTIVE
  To determine the most reliable predictor of radiofrequency (RF) ablation zone volume among three-dimensional (3D) volumetric colour Doppler vascular indices in an in vitro blood-perfused bovine liver model.
  
  
  METHODS
  3D colour Doppler volume data of the local hepatic parenchyma were acquired from 37 areas of 13 bovine livers connected to an in vitro oxygenated blood perfusion system. Doppler vascular indices of vascularization index (VI), flow index (FI) and vascularization flow index (VFI) were obtained from the volume data using 3D volume analysis software. 37 RF ablations were performed at the same locations where the ultrasound data were obtained from. The relationship of these vascular indices and the ablation zone volumes measured from gross specimens were analyzed using a general linear mixed model fit with random effect for liver and backward stepwise regression analysis.
  
  
  RESULTS
  FI was significantly associated with ablation zone volumes measured on gross specimens (p = 0.0047), but explained little of the variance (Rβ2= 0.21). Ablation zone volume decreased by 0.23 cm3(95% confidence interval: -0.38, -0.08) for every 1 increase in FI. Neither VI nor VFI was significantly associated with ablation zone volumes (p > 0.05).
  
  
  CONCLUSIONS
  Although FI was associated with ablation zone volumes, it could not sufficiently explain their variability, limiting its clinical applicability. VI, FI and VFI are not clinically useful in the prediction of RF ablation zone volume in the liver. Advances in knowledge: Despite a significant association of FI with ablation zone volumes, VI, FI and VFI cannot be used for their prediction. Different Doppler vascular indices need to be investigated for clinical use.
authors.affiliation: 1 Department of Radiology, University of Colorado School of Medicine, Aurora, CO, USA.
authors.forename: Samuel
authors.identifier: http://orcid.org/0000-0001-5983-1368
authors.initials: S
authors.lastname: Chang
authors.affiliation: 1 Department of Radiology, University of Colorado School of Medicine, Aurora, CO, USA.
authors.forename: Anthony C
authors.initials: AC
authors.lastname: Lanctot
authors.affiliation: 2 Department of Surgery, University of Colorado School of Medicine, Aurora, CO, USA.
authors.forename: Martin D
authors.initials: MD
authors.lastname: McCarter
authors.affiliation: 3 Department of Biostatistics and Informatics, University of Colorado School of Public Health, Aurora, CO, USA.
authors.forename: Katherine M
authors.initials: KM
authors.lastname: Roberts
authors.affiliation: 3 Department of Biostatistics and Informatics, University of Colorado School of Public Health, Aurora, CO, USA.
authors.forename: Deborah H
authors.initials: DH
authors.lastname: Glueck
authors.affiliation: 1 Department of Radiology, University of Colorado School of Medicine, Aurora, CO, USA.
authors.forename: Gerald D
authors.initials: GD
authors.lastname: Dodd
mesh_terms: D000818:Animals; D017115:Catheter Ablation; D002417:Cattle; D021621:Imaging, Three-Dimensional; D008099:Liver / Q000098:blood supply / Q000000981:diagnostic imaging / Q000601:surgery*; D008102:Liver Circulation / Q000502:physiology; D008953:Models, Anatomic; D009929:Organ Size; D018615:Ultrasonography, Doppler, Color