Abstract:

Objective To assess the application of spatio-temporal image correlation(STIC) for normal and arrhythmic fetal cardiac function examination from 21 to 32⁺⁶ gestational weeks. Methods Fetal heart ventricular end-diastole volumes(EDV) and end-systole volumes(ESV) were measured with STIC and virtual organ computer aided analysis(VOCAL) in 60 normal fetuses and 12 fetuses with isolated arrhythmia from 21 to 32⁺⁶ gestational weeks. The stroke volume(SV), cardiac output(CO) and ejection fraction(EF) of each ventricle were calculated with EDV and ESV.The normal reference values of EDV, ESV, SV, CO and EF of left and right ventricles were calculated with statistical methods. The correlation between cardiac parameters(including EDV, ESV, SV, CO and EF) and gestational age were analyzed. Every fetus had a follow-up outcome after birth. Results The cardiac functions of 60 normal fetuses: We obtained the normal reference values of EDV, ESV, SV and CO of left and right ventricles according to different gestational weeks(Table 1), which increased and had significant positive correlations with gestational age(P<0.001). The normal reference values of LVEF(left ventricular ejection fraction) and RVEF(right ventricular ejection fraction) were(55%-57%) and (53%-56%) respectively from 21 to 32⁺⁶ gestational weeks, which had negative correlations with gestational age(r=-0.41, -0.41, all P=0.001). The cardiac functions of 12 fetuses with isolated arrhythmia: The types of fetal arrhythmia included 7 cases with atrial premature beats, 2 cases with bradyarrhythmias, 1 case with atrial premature beat and atrial tachycardia, 1 case with atrial premature beat and atrioventricular block and 1 case with undefined type. EDV, ESV, SV, CO, LVEF(48%-66%) and RVEF(48%-64%) of 12 isolated arrhythmic fetuses were roughly normal according to normal reference values of different gestational weeks. All of 12 fetuses with isolated arrhythmia were full term deliveries, and healthy after birth. Conclusion STIC technique can accurately measure fetal ventricular volumes and evaluate fetal cardiac function.It is also helpful to assess arrhythmic fetal cardiac function.

Key words: spatio-temporal image correlation, dynamic three-dimensional ultrasonography, fetal cardiac function, fetal arrhythmia