A novel fully automated method for mitral regurgitant orifice area quantification.
BACKGROUND
Effective regurgitant orifice area (EROA) in mitral regurgitation (MR) is difficult to quantify. Clinically it is measured using the proximal isovelocity surface area (PISA) method, which is intrinsically not automatable, because it requires the operator to manually identify the mitral valve orifice. We introduce a new fully automated algorithm, ("AQURO"), which calculates EROA directly from echocardiographic colour M-mode data, without requiring operator input.


METHODS
Multiple PISA measurements were compared to multiple AQURO measurements in twenty patients with MR. For PISA analysis, three mutually blinded observers measured EROA from the four stored video loops. For AQURO analysis, the software automatically processed the colour M-mode datasets and analysed the velocity field in the flow-convergence zone to extract EROA directly without any requirement for manual radius measurement.


RESULTS
Reproducibility, measured by intraclass correlation (ICC), for PISA was 0.80, 0.83 and 0.83 (for 3 observers respectively). Reproducibility for AQURO was 0.97. Agreement between replicate measurements calculated using Bland-Altman standard deviation of difference (SDD) was 21,17 and 17mm(2)for the three respective observers viewing independent video loops using PISA. Agreement between replicate measurements for AQURO was 6, 5 and 7mm(2)for automated analysis of the three pairs of datasets.


CONCLUSIONS
By eliminating the need to identify the orifice location, AQURO avoids an important source of measurement variability. Compared with PISA, it also reduces the analysis time allowing analysis and averaging of data from significantly more beats, improving the consistency of EROA quantification. AQURO, being fully automated, is a simple, effective enhancement for EROA quantification using standard echocardiographic equipment.
International Centre for Circulatory Health, National Heart and Lung Institute, Imperial College, 59-61 North Wharf Road, London W21LA, UK. michela.moraldo@gmail.com
Michela
M
Moraldo
Corinna
C
Bergamini
Anura S N
AS
Malaweera
Niti M
NM
Dhutia
Punam A
PA
Pabari
Keith
K
Willson
Resham
R
Baruah
Charlotte
C
Manisty
Justin E
JE
Davies
Xiao Y
XY
Xu
Alun D
AD
Hughes
Darrel P
DP
Francis
D000368:Aged; D057205:Automation, Laboratory / Q000379:methods*; D004452:Echocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging* / Q000503:physiopathology; D016037:Single-Blind Method; D014741:Video Recording / Q000379:methods*