3-DIMENSIONAL ECHOCARDIOGRAPHY - IN-VITRO AND IN-VIVO VALIDATION OF LEFT-VENTRICULAR MASS AND COMPARISON WITH CONVENTIONAL ECHOCARDIOGRAPHIC METHODS

Objectives. This study aimed to validate a method for mass computation in vitro and in vivo and to compare it with conventional methods. Bac kground. Conventional echocardiographic methods of determining left ve ntricular mass are limited by assumptions of ventricular geometry and image plane positioning. To improve accuracy, we developed a three-dim ensional echocardiographic method that uses nonparallel, nonintersecti ng short-axis planes and a polyhedral surface reconstruction algorithm for mass computation. Methods. Eleven fixed hearts were imaged by thr ee-dimensional echocardiography, and mass was determined in vitro by m ultiplying the myocardial volume by the density of each heart and comp aring it with the true mass. Mass at diastole and systole by three-dim ensional echocardiography and magnetic resonance im aging (MRI) was co mpared in vivo in 15 normal subjects. Ten subjects also underwent imag ing by one- and two-dimensional echocardiography, and mass was determi ned by Penn convention, area-length and truncated ellipsoid algorithms . Results. In vitro results were r = 0.995, SEE 2.91 g, accuracy 3.47% . In vivo interobserver variability for systole and diastole was 16.7% to 27%, 14% to 18.1% and 6.3% to 12.8%, respectively, for one-, two- and three-dimensional echocardiography and was 7.5% for MRI at end-dia stole. The latter two agreed closely with regard to diastolic mass (r = 0.895, SEE 11.1 g) and systolic mass (r = 0.926, SEE 9.2 g). These r esults were significantly better than correlations between MRI and the Penn convention (r = 0.725, SEE 25.6 g for diastole; r = 0.788, SEE 2 8.7 g for systole), area-length (r = 0.694, SEE 24.2 g for diastole; r = 0.717, SEE 28.2 g for systole) and truncated ellipsoid algorithms ( r = 0.687, SEE 21.8 g for diastole; r = 0.710, SEE 24.5 g for systole) . Conclusions. Image plane positioning guidance and elimination of geo metric assumptions by three-dimensional echocardiography achieve high accuracy for left ventricular mass determination in vitro. It is assoc iated with higher correlations and lower standard errors than conventi onal methods in vivo.