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 33 weeks and 6 days 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 ± 4.9 years, 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 (R2 ) 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.