Unbiased and efficient estimation of left ventricular volumes by three-dimensional echocardiography with coaxial sections. Validation with magnetic resonance imaging

The objective of this study was to investigate the degree of bias with coax ial three-dimensional echocardiography in an experimental animal setup and to establish the minimum number of sections needed for estimation of left v entricular (LV) volume. Epicardial coaxial echocardiography and magnetic re sonance imaging (MRI) was used to measure LV volume in 14 pigs, with chroni c remodeled left ventricles induced by repeated intracoronary microemboliza tions. In addition, six animals underwent serial MRI at baseline, immediate ly after intracoronary microembolization. and after 119-165 days (mean 129 days). Coaxial echocardiography was performed by rotational acquisition of long-axis sections starting from an arbitrary angle. Planimetered MRI conto urs of LV endocardial borders were analyzed to investigate the relationship between the number of coaxial sections, and the precision of volume estima tes. The mean +/- 2SD of the differences between coaxial epicardial echocar diography with six sections and MRI were -2.5 +/- 16.4 ml, 0.8 +/- 13.1 ml, and 2% +/- 14% for end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF)I respectively. Numerical analysis conducted on M RI contours of LV endocardial borders showed that with six coaxial sections the average coefficient of error was <1% for the EDV and ESV. Three-dimens ional echocardiography with six coaxial sections provides unbiased LV volum e estimation with minimal geometric error.