Head-to-head comparison of two-dimensional and three-dimensional echocardiographic methods for left atrial chamber...

Limited data are available on the accuracy of quantification methods for left atrial (LA) volumes using two-dimensional (2D) and particularly real-time three-dimensional echocardiographic (RT3DE) methods in comparison with a reference standard. The aim of this study was to perform a head-to-head comparison between 2D and RT3DE methods with magnetic resonance imaging (MRI) as the reference standard.

LA volumes derived from 2D echocardiographic methods (i.e., biplane modified Simpson's, biplane area-length, and prolate ellipse methods) and from RT3DE methods (i.e., 4D LA Analysis and QLAB) in 60 consecutive patients were compared with MRI measurements. Offline analysis time was recorded.

The biplane modified Simpson's and area-length methods showed good intraclass correlations with MRI for maximum (r = 0.70 and r = 0.69, P < .001) and minimum (r = 0.83 and r = 0.82, P < .001) volumes. Although RT3DE methods led to moderate increases in correlations for maximum (r = 0.94 and 0.70, P < .001) and minimum (r = 0.95 and r = 0.90, P < .001) volumes and narrower Bland-Altman limits of agreement than 2D echocardiographic methods, offline analysis time was higher for RT3DE (155-161 vs 103-144 sec). Compared with MRI, maximum and minimum LA volumes were underestimated by -4.7% and -8.9%, respectively, using 4D LA Analysis, by -15.7% and -14.9% using QLAB, by -12.3% and -4.4% using the biplane Simpson's method, by -13.7% and -6.8% using the area-length method, and by -48.2% and -50.5% using the prolate ellipse method.

The biplane Simpson's and area-length methods offer reasonable accuracy for LA chamber quantification across a broad range of volumes, while RT3DE methods lead to a moderate improvement in accuracy at the cost of more elaborate offline analysis.