title: Optimal C-arm angulation during transcatheter aortic valve replacement: Accuracy of a rotational C-arm computed tomography based three dimensional heart model.
abstract: OBJECTIVE
  To investigate the accuracy of a rotational C-arm CT-based 3D heart model to predict an optimal C-arm configuration during transcatheter aortic valve replacement (TAVR).
  
  
  METHODS
  Rotational C-arm CT (RCT) under rapid ventricular pacing was performed in 57 consecutive patients with severe aortic stenosis as part of the pre-procedural cardiac catheterization. With prototype software each RCT data set was segmented using a 3D heart model. From that the line of perpendicularity curve was obtained that generates a perpendicular view of the aortic annulus according to the right-cusp rule. To evaluate the accuracy of a model-based overlay we compared model- and expert-derived aortic root diameters.
  
  
  RESULTS
  For all 57 patients in the RCT cohort diameter measurements were obtained from two independent operators and were compared to the model-based measurements. The inter-observer variability was measured to be in the range of 0°-12.96° of angular C-arm displacement for two independent operators. The model-to-operator agreement was 0°-13.82°. The model-based and expert measurements of aortic root diameters evaluated at the aortic annulus (r= 0.79,P< 0.01), the aortic sinus (r= 0.93,P< 0.01) and the sino-tubular junction (r= 0.92,P< 0.01) correlated on a high level and the Bland-Altman analysis showed good agreement. The interobserver measurements did not show a significant bias.
  
  
  CONCLUSIONS
  Automatic segmentation of the aortic root using an anatomical model can accurately predict an optimal C-arm configuration, potentially simplifying current clinical workflows before and during TAVR.
authors.affiliation: Verena Veulemans, Katharina Hellhammer, Tobias Zeus, Ralf Westenfeld, Malte Kelm, Jan Balzer, Department of Medicine, Division of Cardiology, Pulmonary Diseases, Vascular Medicine, University Hospital Düsseldorf, 40225 Düsseldorf, Germany.
authors.forename: Verena
authors.initials: V
authors.lastname: Veulemans
authors.affiliation: Verena Veulemans, Katharina Hellhammer, Tobias Zeus, Ralf Westenfeld, Malte Kelm, Jan Balzer, Department of Medicine, Division of Cardiology, Pulmonary Diseases, Vascular Medicine, University Hospital Düsseldorf, 40225 Düsseldorf, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Mollus
authors.affiliation: Verena Veulemans, Katharina Hellhammer, Tobias Zeus, Ralf Westenfeld, Malte Kelm, Jan Balzer, Department of Medicine, Division of Cardiology, Pulmonary Diseases, Vascular Medicine, University Hospital Düsseldorf, 40225 Düsseldorf, Germany.
authors.forename: Axel
authors.initials: A
authors.lastname: Saalbach
authors.affiliation: Verena Veulemans, Katharina Hellhammer, Tobias Zeus, Ralf Westenfeld, Malte Kelm, Jan Balzer, Department of Medicine, Division of Cardiology, Pulmonary Diseases, Vascular Medicine, University Hospital Düsseldorf, 40225 Düsseldorf, Germany.
authors.forename: Max
authors.initials: M
authors.lastname: Pietsch
authors.affiliation: Verena Veulemans, Katharina Hellhammer, Tobias Zeus, Ralf Westenfeld, Malte Kelm, Jan Balzer, Department of Medicine, Division of Cardiology, Pulmonary Diseases, Vascular Medicine, University Hospital Düsseldorf, 40225 Düsseldorf, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Hellhammer
authors.affiliation: Verena Veulemans, Katharina Hellhammer, Tobias Zeus, Ralf Westenfeld, Malte Kelm, Jan Balzer, Department of Medicine, Division of Cardiology, Pulmonary Diseases, Vascular Medicine, University Hospital Düsseldorf, 40225 Düsseldorf, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Zeus
authors.affiliation: Verena Veulemans, Katharina Hellhammer, Tobias Zeus, Ralf Westenfeld, Malte Kelm, Jan Balzer, Department of Medicine, Division of Cardiology, Pulmonary Diseases, Vascular Medicine, University Hospital Düsseldorf, 40225 Düsseldorf, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Westenfeld
authors.affiliation: Verena Veulemans, Katharina Hellhammer, Tobias Zeus, Ralf Westenfeld, Malte Kelm, Jan Balzer, Department of Medicine, Division of Cardiology, Pulmonary Diseases, Vascular Medicine, University Hospital Düsseldorf, 40225 Düsseldorf, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Weese
authors.affiliation: Verena Veulemans, Katharina Hellhammer, Tobias Zeus, Ralf Westenfeld, Malte Kelm, Jan Balzer, Department of Medicine, Division of Cardiology, Pulmonary Diseases, Vascular Medicine, University Hospital Düsseldorf, 40225 Düsseldorf, Germany.
authors.forename: Malte
authors.initials: M
authors.lastname: Kelm
authors.affiliation: Verena Veulemans, Katharina Hellhammer, Tobias Zeus, Ralf Westenfeld, Malte Kelm, Jan Balzer, Department of Medicine, Division of Cardiology, Pulmonary Diseases, Vascular Medicine, University Hospital Düsseldorf, 40225 Düsseldorf, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Balzer
keywords: Aortic stenosis; Degenerative valve disease; Imaging modalities; Transcatheter aortic valve replacement