Initial study of real-time three-dimensional echocardiography for quantifying right ventricular volume in vitro

Objective: To initially evaluate the feasibility and accuracy of real-time three-dimensional echocardiography (RT-3DE) for quantifying the of the right ventricle in experimental study. Methods: Ten excised porcine hearts were examined by RT-3DE and conventional two-dimensional(2D) echocardiography with Philips Sonos 7500 echocardiographic system. The measurements of their right ventricular volumes were outlined and calculated by 2-plane, 4-plane, 8-plane and 16-plane methods with the 4D Cardio-View RT of TomTec image system, and their results were compared with those of 2D Lenth-method and 2D biplane Simpson-method. The true volumes of right ventricular Si-rubber models of excised porcine hearts measured by water displacement were served as a reference standard. Results: Full volume imaging in all excised porcine hearts was well displayed by RT-3DE. The right ventricular shapes of RT-3DE were similar to those of Si-rubber models of excised porcine hearts. There was no significant difference(P0.05) between the measurements with RT-3DE 16-plane(64.05±18.20)ml, 8-plane(61.83±17.99)ml, 2DE Lenth-method(57.31±15.26)ml and true volumes of right ventricular Si-rubber models of excised porcine hearts(62.94±15.82)ml, but there was significant difference between the measurements with RT-3DE 4-plane(49.37±19.74)ml, 2-plane(40.75±17.61)ml, 2D biplane Simpson-method(37.21±16.41)ml and true volumes of right ventricular Si-rubber models. Meanwhile,the measurements with RT-3DE 16-plane and 8-plane were closer to true volumes of right ventricular Si-rubber models. The correlation of RT-3DE 16-plane(r=0.97, P0.001) and 8-plane(r=0.94, P0.001)with true volumes of right ventricular Si-rubber models is more than that of 2D Lenth-method(r=0.82, P0.012) and 2D biplane Simpson-method(r=0.79, P0.018) with true volumes of right ventricular Si-rubber models. Conclusion: By displaying real-time spatial shape of right ventricle, RT-3DE will be a valuable and accurate new technique to quantify right ventricular volume.