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.
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.
Sitges
Marta
M
Cardiovascular Imaging Center, Department of Cardiovascular Medicine, The Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.
Jones
Michael
M
Shiota
Takahiro
T
Qin
Jian Xin
JX
Tsujino
Hiroyuki
H
Bauer
Fabrice
F
Kim
Yong Jin
YJ
Agler
Deborah A
DA
Cardon
Lisa A
LA
Zetts
Arthur D
AD
Panza
Julio A
JA
Thomas
James D
JD
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