title: Three-Dimensional Field Optimization Method: Gold-Standard Validation of a Novel Color Doppler Method for Quantifying Mitral Regurgitation.
abstract: Accurate diagnosis of mitral regurgitation (MR) severity is central to proper treatment. Although numerous approaches exist, an accurate, gold-standard clinical technique remains elusive. The authors previously reported on the initial development and demonstration of the automated three-dimensional (3D) field optimization method (FOM) algorithm, which exploits 3D color Doppler ultrasound imaging and builds on existing MR quantification techniques. The aim of the present study was to extensively validate 3D FOM in terms of accuracy, ease of use, and repeatability.
  
  
  
  Three-dimensional FOM was applied to five explanted ovine mitral valves in a left heart simulator, which were systematically perturbed to yield a total of 29 unique regurgitant geometries. Three-dimensional FOM was compared with a gold-standard flow probe, as well as the most clinically prevalent MR volume quantification technique, the two-dimensional (2D) proximal isovelocity surface area (PISA) method.
  
  
  
  Overall, 3D FOM overestimated and 2D PISA underestimated MR volume, but 3D FOM error had smaller magnitude (5.2 ± 9.9 mL) than 2D PISA error (-6.9 ± 7.7 mL). Two-dimensional PISA remained superior in diagnosis for round orifices and especially mild MR, as predicted by ultrasound physics theory. For slit-type orifices and severe MR, 3D FOM showed significant improvement over 2D PISA. Three-dimensional FOM processing was technically simpler and significantly faster than 2D PISA and required fewer ultrasound acquisitions. Three-dimensional FOM did not show significant interuser variability, whereas 2D PISA did.
  
  
  
  Three-dimensional FOM may provide increased clinical value compared with 2D PISA because of increased accuracy in the case of complex or severe regurgitant orifices as well as its greater repeatability and simpler work flow.
authors.affiliation: The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia.
authors.forename: Eric L
authors.initials: EL
authors.lastname: Pierce
authors.affiliation: The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia.
authors.forename: Jean Pierre M
authors.initials: JP
authors.lastname: Rabbah
authors.affiliation: Philips Health Tech, Andover, Massachusetts.
authors.forename: Karl
authors.initials: K
authors.lastname: Thiele
authors.affiliation: Philips Health Tech, Andover, Massachusetts.
authors.forename: Qifeng
authors.initials: Q
authors.lastname: Wei
authors.affiliation: The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia.
authors.forename: Brani
authors.initials: B
authors.lastname: Vidakovic
authors.affiliation: The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia.
authors.forename: Morten O
authors.initials: MO
authors.lastname: Jensen
authors.affiliation: Echocardiography Laboratory of the Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Judy
authors.initials: J
authors.lastname: Hung
authors.affiliation: The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia. Electronic address: ajit.yoganathan@bme.gatech.edu.
authors.forename: Ajit P
authors.initials: AP
authors.lastname: Yoganathan
mesh_terms: D000818:Animals; D018618:Echocardiography, Doppler, Color / Q000379:methods* / Q000592:standards*; D019560:Echocardiography, Three-Dimensional / Q000379:methods* / Q000592:standards*; D007089:Image Enhancement / Q000379:methods* / Q000592:standards*; D066298:In Vitro Techniques; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging*; D015588:Observer Variation; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012756:Sheep
keywords: Diagnostic; Doppler ultrasound; Flow convergence; Mitral regurgitation; Three-dimensional echocardiography