Variables Influencing the Accuracy of Right Ventricular Volume Assessment by Real-time 3-Dimensional Echocardiography: An In Vitro Validation Study

Background Preliminary experience with matrix-array real-time (RT) 3-dimensional echocardiography (3DE) in pediatric patients has demonstrated consistently lower right ventricular volume (RVV) compared with magnetic resonance imaging. Our hypothesis was that variables in RT 3DE acquisition and offline analysis, including gain settings, thickness, and orientation of disks, could alter RVV measurements. Methods Displacements of water from latex models derived from excised lamb hearts were used for comparison. RT 3DE volume acquisitions were performed using a matrix-array probe (2-4 MHz); RVVs were calculated offline using summation of disks method. Results No significant difference and excellent agreement was found for comparison of RT 3DE with displacement of water using 5-mm cut planes, optimal gain settings, and short-axis tracings. Different gain settings and long-axis tracings significantly affected RVV. A slice thickness of 13 mm or greater affected volume measurements. Conclusions RT 3DE can accurately measure RVV. Specific variables will alter volumes measurements and must be considered in clinical studies.