Assessment of fetal heart aortic and pulmonary valve annulus area by three-dimensional ultrasonography: reference curves and applicability in congenital heart diseases.

OBJECTIVES: To determine reference curves for fetal aortic and pulmonary valve annulus area by three-dimensional ultrasonography using the spatio-temporal image correlation (STIC) in the rendering mode, and to ascertain its applicability in congenital heart disease (CHD). METHODS: We performed a retrospective cross-sectional study of 328 normal fetuses and 42 fetuses with CHD between 20 and 33 weeks 6 days of gestation. The outflow plane view of the great vessels was used to measure the areas of the valvar annuli, and the measurements were performed in systole. A linear regression model adjusted according to the determination coefficient (R2) was utilized to construct the reference intervals. The concordance correlation coefficient (CCC) was used to calculate the reproducibility of the mitral and tricuspid valve areas. RESULTS: The mean ± standard deviation (SD) of the aortic and pulmonary valve annulus areas ranged from 6.6 ± 1.2 to 32.9 ± 1.1 mm2 and 10.7 ± 1.3 to 40.3 ± 1.2 mm2, respectively. We observed a linear relationship and strong positive correlation between the area of the aortic and pulmonary valve annuli with r=0.97 and 0.96, respectively. Good intra (CCC=0.99) and interobserver agreement (CCC=0.98) was observed for the measurement of the aortic valve annulus area. A good intra (CCC=0.99) and interobserver (CCC=0.97) agreement was also observed for the measurement of the pulmonary valve annulus area. The mean ± SD of the difference of the areas of the aortic and pulmonary valve annuli between the normal fetuses and those with CHD were -1.801 ± 1.429 mm2 (p=0.208) and -1.033 ± 1.467 mm2 (p<0.0001), respectively. CONCLUSIONS: The reference curves for the areas of the aortic and pulmonary valve annuli of fetal hearts were determined, and showed good inter and intraobserver reproducibility. The constructed reference curves showed applicability in different types of CHD.

Fetal cardiac function by three-dimensional ultrasound using 4D-STIC and VOCAL - an update.

Three- and four-dimensional (3D/4D) ultrasonography with spatio-temporal image correlation (4D-STIC) allows obtaining fetal cardiac volumes and their static and real-time analysis in multiplanar and rendering modes. Cardiac biometrics and Doppler-echocardiographic parameters for evaluation of fetal heart function, including cardiac output and stroke volume, can be analyzed using M-mode, two-dimensional (2D), and 3D/4D cardiac ultrasound. In recent years, functional echocardiography has been used to study fetuses without a structurally cardiac defect but who are at risk of heart failure due to the presence of extra-cardiac conditions, such as, fetal growth restriction, tumors/masses, twin-to-twin transfusion syndrome, fetal anemia (Rh alloimmunization), congenital infections, or maternal diabetes mellitus. The assessment of cardiac function provides important information on hemodynamic status and can help optimize the best time for delivery and reduce perinatal morbidity and mortality. Since 2003, with the advent of the 4D-STIC software, it is possible to evaluate the fetal heart in multiplanar, and rendering modes. This technology associated with virtual organ computer-aided analysis (VOCAL) enables determining the ventricular volume (end-diastole, end-systole), the stroke-volume, the ejection fraction, and the cardiac output of each ventricle. Since 2004, several studies demonstrated that the 4D-STIC and VOCAL had good reproducibility to measure cardiac volumes This study reviews published studies that evaluated the fetal cardiac function by 3D ultrasound using 4D-STIC and VOCAL software.