title: Four-dimensional modelling of the mitral valve by real-time 3D transoesophageal echocardiography: proof of concept.
abstract: OBJECTIVE
  The complexity of the mitral valve (MV) anatomy and function is not yet fully understood. Assessing the dynamic movement and interaction of MV components to define MV physiology during the complete cardiac cycle remains a challenge. We herein describe a novel semi-automated 4D MV model.
  
  
  METHODS
  The model applies quantitative analysis of the MV over a complete cardiac cycle based on real-time 3D transoesophageal echocardiography (RT3DE) data. RT3DE data of MVs were acquired for 18 patients. The MV annulus and leaflets were semi-automatically reconstructed. Dimensions of the mitral annulus (anteroposterior and anterolateral-posteromedial diameter, annular circumference, annular area) and leaflets (MV orifice area, intercommissural distance) were acquired. Variability and reproducibility (intraclass correlation coefficient, ICC) for interobserver and intraobserver comparison were quantified at 4 time points during the cardiac cycle (mid-systole, end-systole, mid-diastole and end-diastole).
  
  
  RESULTS
  Mitral annular dimensions provided highly reliable and reproducible measurements throughout the cardiac cycle for interobserver (variability range, 0.5-1.5%; ICC range, 0.895-0.987) and intraobserver (variability range, 0.5-1.6%; ICC range, 0.827-0.980) comparison, respectively. MV leaflet parameters showed a high reliability in the diastolic phase (variability range, 0.6-9.1%; ICC range, 0.750-0.986), whereas MV leaflet dimensions showed a high variability and lower correlation in the systolic phase (variability range, 0.6-22.4%; ICC range, 0.446-0.915) compared with the diastolic phase.
  
  
  CONCLUSIONS
  This 4D model provides detailed morphological reconstruction as well as sophisticated quantification of the complex MV structure and dynamics throughout the cardiac cycle with a precision not yet described.
authors.affiliation: Department of Cardiac Surgery, Heart Center Leipzig University, Leipzig, Germany thilo.noack@medizin.uni-leipzig.de.
authors.forename: Thilo
authors.initials: T
authors.lastname: Noack
authors.affiliation: Department of Anesthesia, Heart Center Leipzig University, Leipzig, Germany.
authors.forename: Chirojit
authors.initials: C
authors.lastname: Mukherjee
authors.affiliation: Department of Cardiac Surgery, Heart Center Leipzig University, Leipzig, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Kiefer
authors.affiliation: Department of Cardiac Surgery, Heart Center Leipzig University, Leipzig, Germany.
authors.forename: Fabian
authors.initials: F
authors.lastname: Emrich
authors.affiliation: Department of Cardiac Surgery, Heart Center Leipzig University, Leipzig, Germany.
authors.forename: Marcel
authors.initials: M
authors.lastname: Vollroth
authors.affiliation: Image Analytics and Informatics, Siemens Corporate Research, Princeton, NJ, USA.
authors.forename: Razvan Ioan
authors.initials: RI
authors.lastname: Ionasec
authors.affiliation: Image Analytics and Informatics, Siemens Corporate Research, Princeton, NJ, USA.
authors.forename: Ingmar
authors.initials: I
authors.lastname: Voigt
authors.affiliation: Ultrasound Division, Siemens Healthcare, Mountain View, CA, USA.
authors.forename: Helene
authors.initials: H
authors.lastname: Houle
authors.affiliation: Department of Anesthesia, Heart Center Leipzig University, Leipzig, Germany.
authors.forename: Joerg
authors.initials: J
authors.lastname: Ender
authors.affiliation: Department of Cardiac Surgery, Heart Center Leipzig University, Leipzig, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Misfeld
authors.affiliation: Department of Cardiac Surgery, Heart Center Leipzig University, Leipzig, Germany.
authors.forename: Friedrich Wilhelm
authors.initials: FW
authors.lastname: Mohr
authors.affiliation: Department of Cardiac Surgery, Heart Center Leipzig University, Leipzig, Germany.
authors.forename: Joerg
authors.initials: J
authors.lastname: Seeburger
mesh_terms: D000368:Aged; D000465:Algorithms; D001331:Automation; D019560:Echocardiography, Three-Dimensional; D017548:Echocardiography, Transesophageal; D005260:Female; D006439:Hemodynamics; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D008955:Models, Cardiovascular; D015588:Observer Variation; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D013997:Time Factors
keywords: 4D reconstruction; Echocardiography; Mitral valve; Model