title: Automatic measurement of aortic annulus diameter in 3-dimensional transoesophageal echocardiography.
abstract: BACKGROUND
  Transcatheter aortic valve implantation involves percutaneously implanting a biomechanical aortic valve to treat severe aortic stenosis. In order to select a proper device, precise sizing of the aortic valve annulus must be completed.
  
  
  METHODS
  In this paper, we describe a fully automatic segmentation method to measure the aortic annulus diameter in patients with aortic calcification, operating on 3-dimensional transesophageal echocardiographic images. The method is based on state estimation of a subdivision surface representation of the left ventricular outflow tract and aortic root. The state estimation is solved by an extended Kalman filter driven by edge detections normal to the subdivision surface.
  
  
  RESULTS
  The method was validated on echocardiographic recordings of 16 patients. Comparison against two manual measurements showed agreements (mean ±SD) of -0.3 ± 1.6 and -0.2 ± 2.3 mm for perimeter-derived diameters, compared to an interobserver agreement of -0.1 ± 2.1 mm.
  
  
  CONCLUSIONS
  With this study, we demonstrated the feasibility of an efficient and fully automatic measurement of the aortic annulus in patients with aortic disease. The algorithm robustly measured the aortic annulus diameter, providing measurements indistinguishable from those done by cardiologists.
authors.affiliation: GE Vingmed Ultrasound AS, Horten, Norway. jorn.bersvendsen@ge.com.
authors.forename: Jørn
authors.initials: J
authors.lastname: Bersvendsen
authors.forename: Jan O
authors.initials: JO
authors.lastname: Beitnes
authors.forename: Stig
authors.initials: S
authors.lastname: Urheim
authors.forename: Svend
authors.initials: S
authors.lastname: Aakhus
authors.forename: Eigil
authors.initials: E
authors.lastname: Samset
mesh_terms: D000368:Aged; D000465:Algorithms; D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging* / Q000473:pathology; D019560:Echocardiography, Three-Dimensional / Q000379:methods*; D017548:Echocardiography, Transesophageal / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D061205:Vascular Calcification / Q000000981:diagnostic imaging*