Evaluations of the function and the morphology of the fetal heart with three-dimensional ultrasound

Abstract

We studied the feasibility of using free-hand three-dimensional (3D) echocardiography to evaluate fetal cardiac function, and applied state-of-the-art multi-planar (MPR) 3D ultrasound scanning to fetal echocardiography. The heart was scanned from its base to the vessels’ insertion in axial planes, nearly parallel to the conventional four-chamber view, in fan projection. During processing, segmentation of right and left ventricles was performed, end-diastolic and end-systolic volumes were measured, and the ejection fraction calculated for each ventricle. MPR was used to obtain the five axial planes of the fetal heart for anatomic evaluation, even in cases when fetal lie did not allow for ideal apical FCV. End-systolic (ES) and end-diastolic (ED) volumes and ejection fraction (EF) of the right ventricle were compared with the same parameters of the left ventricle. The mean right ventricle ejection fraction was 53.4 ± 11.2%. The mean left ventricle ejection fraction was 56.7 ± 14.6%. Mean combined ejection fraction of ventricles during gestation was 54.8 ± 10.8%. The combined ejection fractions of the ventricles seemed to remain constant during the gestational ages studied, independent of estimated fetal weight (EFW). Combined fetal cardiac output (ml/min) increased exponentially as pregnancy progressed. Mean combined cardiac output of fetuses at 21–24 weeks was 40.4 ml/min (95 ml/kg/min of EFW). In all cases, satisfactory anatomical structure was demonstrated with the MPR views obtained. 3D echocardiography can provide estimates of ventricular volume and function and may in the future be used for evaluation of fetuses with congenital heart disease, and enable simplified examination of the fetal heart.