Evaluation of 24-segment sphericity index of fetal heart using FetalHQ

To evaluate the 24-segment sphericity index (SI) of the fetal heart using FetalHQ regarding the change with advancing gestation and reproducibility.

Eighty-one pregnant women at 18-21 + 6 and 28-31 + 6 weeks were studied using FetalHQ to calculate 24-segment SI of left and right ventricles. Intra- and inter-class correlation coefficients and intra- and inter-observer agreements of measurements for SI were assessed in each segment.

With respect to intra-observer reproducibility, all SI values showed correlations between 0.596 and 0.774 for the left ventricle, and between 0.491 and 0.764 for the right ventricle, with good intra-observer agreements except for right ventricular segment 11-15. With respect to inter-observer reproducibility, all SI values showed correlations between 0.473 and 0.755 for the left ventricle, and between 0.48 and 0.767 for the right ventricular segment 1-18. However, right ventricular segment 19-24 showed no correlations. Good inter-observer agreements were noted in the right ventricle, whereas poor inter-observer agreements were evident in the left ventricle.There were significant differences in the mean SI values in the apical segment of the left ventricle between 18-21 + 6 and 28-31 + 6 weeks (p < .05), whereas there were no significant differences in the mean SI values in the right ventricle between both gestational ages.

These results show that measurements of 24-segment SI of fetal heart had relatively low reliability of measurements performed by experienced sonographers. This may suggest that more training on proper placement of the 3 end-systolic and end-diastolic reference points during the initial analysis may be relevant.