Quantification of pericardial effusions by three-dimensional echocardiography

Abstract Objectives . The purpose of this study was to examine the accuracy of three-dimensional echocardiography for the quantification of asymmetric pericardial effusion volume and to compare this new technique with two-dimensional echocardiography. Background . Quantification of pericardial effusion by two-dimensional echocardiography relies on a symmetric distribution of the fluid. Three-dimensional echocardiography can quantitate volume without these limitations, but its accuracy for pericardial effusin volume has not been assessed. Methods . In six open chest dogs, 41 different asymmetrically distributed pericardial effusions of known volume were created by serial infusions of fluid through a pericardial catheter. The hearts were imaged using an automated echocardiographic method that integrates three-dimensional spatial and imaging data. The surfaces of the pericardial sac and heart were then reconstructed, and the volumes of pericardial effusions were calculated. Two-dimensional echocardiography was performed simultaneously, and volumes were calculated using the prolate ellipsoid method. Asymmetric distribution of the fluid was obtained by applying localized hydrostatic pressure to the pericardium. Results . The volumes of pericardial effusion quantified using three-dimensional echocardiography correlated well with actual volumes (y = 1.0x − 1.4, SEE = 7.7 ml, r = 0.98). Two-dimensional echocardiography had an acceptable correlation (y = 1.0x + 2.3, SEE = 23 ml, r = 0.84), but a marked degree of variation from the true value was observed for any individual measurement. Conclusions . Three-dimensional echocardiography accurately quantifies pericardial effusion volume in vivo, even when the fluid is distributed asymmetrically, whereas two-dimensional echocardiography is less reliable. This new technique may be of clinical value in quantitating pericardial effusion, especially in the serial evaluation of asymmetric or loculated effusions.