Anatomic validation of a novel method for left ventricular volume and mass measurements with use of real-time 3-dimensional echocardiography.

Assessment of left ventricular (LV) volumes and mass is a critical element in the evaluation of patients with cardiovascular disease. However, most non-invasive methods used for the quantitative measurements of LV volume and mass have important intrinsic limitations. Real-time 3-dimensional echocardiography (RT3D echo) is a new technique capable of acquiring volumetric images without cardiac or respiratory gating. The purpose of this study was to develop and validate a system for rapid LV volume and mass measurements with the use of RT3D echo images. To this end, in 11 explanted sheep hearts, the left ventricle was instrumented with a latex balloon and filled with known volumes of saline solution. Two independent observers made volume calculations from images acquired with RT3D echo. In addition, 21 open-chest sheep were imaged with RT3D echo for LV mass calculation. Anatomic LV mass was determined after removing the heart. A strong correlation was observed between the actual LV volumes and those calculated from the RT3D echo images (r = 0.99; y = 1.31 + 0.98x; standard error of the estimate = 2.2 mL). An analysis of intraobserver and interobserver variabilities revealed high indexes of agreement. A strong correlation was observed between actual LV mass and that calculated from RT3D echo images (r = 0.94; y = 14.4 + 0.89x; standard error of the estimate = 8.5 gm). Thus RT3D echo images allow rapid and accurate measurements of LV volume and mass. This technique may expand the use of cardiac ultrasonography for the quantitative assessment of heart disease.

Real-time three-dimensional echocardiography for measurement of left ventricular volumes.

Left ventricular (LV) volumes are important prognostic indexes in patients with heart disease. Although several methods can evaluate LV volumes, most have important intrinsic limitations. Real-time 3-dimensional echocardiography (RT3D echo) is a novel technique capable of instantaneous acquisition of volumetric images. The purpose of this study was to validate LV volume calculations with RT3D echo and to determine their usefulness in cardiac patients. To this end, 4 normal subjects and 21 cardiac patients underwent magnetic resonance imaging (MRI) and RT3D echo on the same day. A strong correlation was found between LV volumes calculated with MRI and with RT3D echo (r = 0.91; y = 20.1 + 0.71x; SEE 28 ml). LV volumes obtained with MRI were greater than those obtained with RT3D echo (126 +/- 83 vs 110 +/- 65 ml; p = 0.002), probably due to the fact that heart rate during MRI acquisition was lower than that during RT3D echo examination (62 +/- 11 vs 79 +/- 16 beats/min; p = 0.0001). Analysis of intra- and interobserver variability showed strong indexes of agreement in the measurement of LV volumes with RT3D echo. Thus, LV volume measurements with RT3D echo are accurate and reproducible. This technique expands the use of ultrasound for the noninvasive evaluation of cardiac patients and provides a new tool for the investigational study of cardiovascular disease.