To evaluate whether electronic spatial-temporal image correlation (eSTIC) technology has advantages over spatial-temporal image correlation (STIC) technology in displaying fetal heart diagnostic views.

This was a self-control trial of 64 normal singleton fetuses at 18 to 24 weeks of gestation who underwent prenatal ultrasound examination at the ultrasound department of Shaoxing Women & Children's Hospital from January to June 2019. In all fetuses, the position of the spine in the four chamber view was from 5∶00 to 7∶00. For each fetus, eSTIC and STIC of the fetal heart were performed with an electronic 4D probe and a conventional mechanical 4D probe. respectively. The sonographic volumes were computer stored and subsequently analyzed using 4D view software. Eight diagnostic views of fetal heart were displayed by orthogonal triplane mode or tomographic ultrasound imaging mode: (1) standard four chamber; (2) left ventricular outflow tract; (3) short-axis view of great vessels/right ventricular outflow tract; (4) three vessels and trachea; (5) abdomen/stomach; (6) ductal arch; (7) aortic arch; and (8) superior and inferior vena cava. The quality of the reconstructed images was categorized into three levels: excellent, fair, and poor. Excellent or fair quality was regarded as qualified, and poor quality was regarded as unqualified. Paired Chi square test was used to compare the qualified rate of the two methods, and the image quality of the two methods was compared by rank sum test.

Both technologies collected 64 volume data sets, and the acquisition success rates were both 100%. There were no significant differences in the qualified rates of eSTIC and STIC for standard four chamber view, left ventricular outflow tract view, short-axis view of great vessels/right ventricular outflow tract, three vessels and trachea view, and abdomen/stomach view (P＞0.05), but for ductal arch view, aortic arch view, and superior and inferior vena cava view, the qualified rates of eSTIC were better than those of STIC (93.8% vs 71.9% for all), and the differences were statistically significant (P=0.001 for all). The quality of all the reconstructed images of diagnostic views in eSTIC was better than that that of STIC (P＜0.05).

eSTIC can significantly improve the image quality of fetal heart diagnostic view reconstruction. Compared with STIC, eSTIC has more advantages in displaying longitudinal diagnostic views of fetal heart.