Three-dimensional echocardiography: in-vitro validation of a new, voxel-based method for rapid quantification of ventricular volume in normal and aneurysmal left ventricles.

Abstract

Previous approaches to ventricular volume calculations by 3-dimensional echocardiography (3-DE) required multiple transverse tomographic sectioning and summation of the volumes of parallel disks. These methods were time consuming and beared the risk of missing the apical volume. We investigated the accuracy of a new, rapid method of 3-DE volume measurements in normal (LV) and aneurysmal (aneurLV) left ventricles in fixed pig hearts. 3-D data sets of 12 LV and 8 experimentally created aneurLV were obtained using a TomTec 3-DE system. For 3-DE volume calculations, a rotational axis in the center of the left ventricle (apical-basal orientation) was defined and 3, 6 and 12 equi-angular rotational planes were created. In each plane the endocardial border was traced and the volume of the corresponding wedge was automatically calculated. The measurements were performed by 2 independent investigators blinded to the anatomic volume and were analyzed for inter- and intraobserver variability. The anatomic volumes ranged from 5 to 150 ml and 9 to 40 ml in LV and aneurLV, respectively. The correlation between 3-DE and anatomic volume was excellent for LV and aneurLV traced in 3, 6 and 12 planes (r = 0.94-0.99). Ventricular volume was well predicted by 3-DE reconstruction: SEE 5.5-7.1 ml (LV), 3.0-3.2 ml (aneurLV). The correlation for interobserver measurements was good in both, LV (r = 0.99) and aneurLV (r = 0.94-0.99) even in 3 planes. The intra- and interobserver variabilities were 1.6-3.0 ml (<7%) and 7.2-7.3 ml (<15%) in LV and 1.1-1.6 (<6%) and 2.1-3.3 ml (<14%) in aneurLV respectively. This new 3-DE method of ventricular volume measurements using a rotational approach provides rapid, accurate and reproducible volume measurements in LV and aneurLV.