Transthoracic three-dimensional echocardiographic reconstruction of left and right ventricles: in vitro validation and comparison with magnetic resonance imaging.

Two-dimensional (2D) echocardiographic and angiographic measurements of ventricular volumes are limited by geometric assumptions concerning cavity shape. We compared in vitro the accuracy of a three-dimensional (3D) echocardiographic system suitable for transthoracic imaging to magnetic resonance imaging (MRI) in the measurement of left and right ventricular volumes. Ventricular cast volumes from 14 excised formalin-fixed sheep hearts filled with an agarose solution were compared with data derived from 3D echocardiography and MRI. Left and right ventricular volumes from 3D echocardiographic reconstructions agreed well with actual volumes without significant underestimation or overestimation. MRI progressively underestimated left ventricular volumes as these increased and systematically underestimated right ventricular volumes. Our echocardiographic system designed for 3D transthoracic imaging combines excellent measurements of left and right ventricular volumes and the computed reconstruction of tomographic slices with the full spatial resolution of the original 2D images. Thus in this in vitro model, 3D echocardiography exhibited greater accuracy than MRI.