Three-dimensional echocardiographic volume computation: in vitro comparison to standard two-dimensional echocardiography.

Two-dimensional (2D) echocardiographic methods for quantitative left ventricular volume computation have been shown to have a low predictive accuracy and reproducibility. To address the problem of geometric assumptions and image plane positioning errors inherent in 2D echocardiography, three-dimensional (3D) echocardiographic systems have been constructed that provide spatial registration and display of transducer-image position and orientation. Although 3D echocardiography has been shown to accurately measure volume in vitro and in vivo, only preliminary data exist demonstrating its superiority over standard 2D echocardiography. We calculated the volume of 30 water-filled latex balloon phantoms of varying size (40 to 200 ml) and shape using each method. Fifteen phantoms were nondistorted (ellipsoid or pear shaped); 15 were symmetrically distorted (dumbbell shaped). Although both 2D and 3D echocardiography showed an excellent correlation to the true volume (r = 0.97 and 0.99, respectively), the standard error of the estimate for 2D echocardiography was twofold larger than for 3D echocardiography (SEE = 6.7 ml and 3.52 ml, respectively). The true volume was slightly underestimated by 3D echocardiography (-2.83 ml), whereas 2D echocardiography overestimated a similar amount (+2.87 ml). The accuracy and variability for 2D echocardiography were significantly poorer (5.22% +/- 5.66% and 5.29% +/- 5.6%, p = 0.001 and 0.002, respectively) as compared with 3D echocardiography (3.7% +/- 2.65% and 2.65% +/- 1.9%, respectively). We conclude that 3D echocardiography with guided image plane positioning and a novel algorithm for volume computation (polyhedral surface reconstruction) achieves significantly more accurate and reproducible results than conventional 2D echocardiography with the modified Simpson's rule.(ABSTRACT TRUNCATED AT 250 WORDS)