title: Real-time three-dimensional color doppler evaluation of the flow convergence zone for quantification of mitral regurgitation: Validation experimental animal study and initial clinical experience.
abstract: BACKGROUND
  Pitfalls of the flow convergence (FC) method, including 2-dimensional imaging of the 3-dimensional (3D) geometry of the FC surface, can lead to erroneous quantification of mitral regurgitation (MR). This limitation may be mitigated by the use of real-time 3D color Doppler echocardiography (CE). Our objective was to validate a real-time 3D navigation method for MR quantification.
  
  
  METHODS
  In 12 sheep with surgically induced chronic MR, 37 different hemodynamic conditions were studied with real-time 3DCE. Using real-time 3D navigation, the radius of the largest hemispherical FC zone was located and measured. MR volume was quantified according to the FC method after observing the shape of FC in 3D space. Aortic and mitral electromagnetic flow probes and meters were balanced against each other to determine reference MR volume. As an initial clinical application study, 22 patients with chronic MR were also studied with this real-time 3DCE-FC method. Left ventricular (LV) outflow tract automated cardiac flow measurement (Toshiba Corp, Tokyo, Japan) and real-time 3D LV stroke volume were used to quantify the reference MR volume (MR volume = 3DLV stroke volume - automated cardiac flow measurement).
  
  
  RESULTS
  In the sheep model, a good correlation and agreement was seen between MR volume by real-time 3DCE and electromagnetic (y = 0.77x + 1.48, r = 0.87, P <.001, delta = -0.91 +/- 2.65 mL). In patients, real-time 3DCE-derived MR volume also showed a good correlation and agreement with the reference method (y = 0.89x - 0.38, r = 0.93, P <.001, delta = -4.8 +/- 7.6 mL).
  
  
  CONCLUSIONS
  real-time 3DCE can capture the entire FC image, permitting geometrical recognition of the FC zone geometry and reliable MR quantification.
authors.affiliation: Cardiovascular Imaging Center, Department of Cardiovascular Medicine, The Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.
authors.forename: Marta
authors.initials: M
authors.lastname: Sitges
authors.forename: Michael
authors.initials: M
authors.lastname: Jones
authors.forename: Takahiro
authors.initials: T
authors.lastname: Shiota
authors.forename: Jian Xin
authors.initials: JX
authors.lastname: Qin
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tsujino
authors.forename: Fabrice
authors.initials: F
authors.lastname: Bauer
authors.forename: Yong Jin
authors.initials: YJ
authors.lastname: Kim
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Agler
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Cardon
authors.forename: Arthur D
authors.initials: AD
authors.lastname: Zetts
authors.forename: Julio A
authors.initials: JA
authors.lastname: Panza
authors.forename: James D
authors.initials: JD
authors.lastname: Thomas
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D003199:Computer Systems; D004195:Disease Models, Animal; D018618:Echocardiography, Doppler, Color; D019560:Echocardiography, Three-Dimensional; D005260:Female; D006801:Humans; D007089:Image Enhancement; D008297:Male; D008875:Middle Aged; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000503:physiopathology; D008955:Models, Cardiovascular; D015588:Observer Variation; D015203:Reproducibility of Results; D012756:Sheep; D013223:Statistics as Topic; D013318:Stroke Volume / Q000502:physiology