Evaluation of fetal heart geometry during pregnancy by three-dimensional ultrasound using the STIC rendering mode

Objective: To determine fetal heart geometry during pregnancy using three-dimensional (3D) ultrasound and the spatiotemporal image correlation (STIC) rendering mode. Methods: This prospective, cross-sectional study evaluated 250 normal singleton pregnancies from 20 to 33weeks and 6days of gestation. STIC rendering was used to calculate the eight angles of the fetal heart: apex, base, mitral valve, tricuspid valve, left ventricle, right ventricle, left atrium, and right atrium angles. The concordance correlation coefficient (CCC) was used for intra- and inter-observer tests. Results: The average +/- SD maternal age was 31.7 +/- 4.9years, and the average gestational age was 26.3 +/- 4.2 weeks. There was little variation in fetal heart angles using STIC rendering according to the gestational age, with determination coefficient (R-2) values of 0.01 for the apex and mitral valve angles and <0.01 for the base, tricuspid valve, left ventricle, right ventricle, left atrium, and right atrium angles. Moderate/good intra- and inter-observer concordance was observed for the measurement of fetal heart angles using STIC rendering, and the obtained CCC varied from 0.74 to 0.93. Conclusion: The fetal heart geometry did not present significant variations during pregnancy using 3D ultrasound and the STIC rendering mode.