title: Reproducibility and inter-vendor variability of left ventricular deformation measurements by three-dimensional speckle-tracking echocardiography.
abstract: BACKGROUND
  Myocardial deformation measurements using two-dimensional speckle-tracking echocardiography (STE) are known to vary among vendors. The intervendor agreement of three-dimensional (3D) deformation indices has not been studied. The goals of this study were to determine the intervendor agreement of 3D STE-based measurements of left ventricular (LV) deformation parameters to investigate the intrinsic variability of these measurements and identify the sources of intervendor differences.
  
  
  METHODS
  Real-time full-volume images obtained in 30 subjects with normal LV systolic function using two vendors' equipment (V1 and V2) on the same day were analyzed by two independent observers using two software packages (S1 and S2). Agreement between three technique combinations (V1/S1, V2/S2, and V1/S2) and their intrinsic reproducibility (interobserver and intraobserver agreement) were assessed using intraclass correlation coefficients. Parameters of LV deformation included global longitudinal strain, twist, 3D displacement, and 3D strain and its radial, longitudinal, and circumferential components.
  
  
  RESULTS
  For all three combinations, intertechnique agreement was poor (intraclass correlation coefficient < 0.4), always beyond the intrinsic variability. For all measured parameters, the intertechnique agreement was better when the same software package was used with images from different vendors (V2/S2 vs V1/S2) than when images from same vendor were analyzed using different software (V1/S2 vs V1/S1).
  
  
  CONCLUSIONS
  Three-dimensional STE-derived LV deformation parameters are highly vendor dependent, and the discordance levels are beyond intrinsic measurement variability of any of the tested combinations of imaging equipment and analysis software. This intervendor discordance must be taken into account when interpreting 3D deformation data.
authors.affiliation: University of Chicago Medical Center, Chicago, Illinois 60637, USA.
authors.forename: Etienne
authors.initials: E
authors.lastname: Gayat
authors.forename: Homaa
authors.initials: H
authors.lastname: Ahmad
authors.forename: Lynn
authors.initials: L
authors.lastname: Weinert
authors.forename: Roberto M
authors.initials: RM
authors.lastname: Lang
authors.forename: Victor
authors.initials: V
authors.lastname: Mor-Avi
mesh_terms: D000328:Adult; D000465:Algorithms; D019560:Echocardiography, Three-Dimensional / Q000379:methods; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D015588:Observer Variation; D011446:Prospective Studies; D015203:Reproducibility of Results; D012984:Software; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000503:physiopathology*