New technique for assessing fetal heart growth using three-dimensional ultrasonography: description of the technique and reference curves

Objective: To describe a new technique for assessing fetal growth using three-dimensional ultrasonography (3DUS) using the extended imaging virtual organ computer-aided analysis (XI VOCAL) software and its respective reference curves.

Methods: We conducted a cross-sectional study on 303 normal singleton pregnancies between their 20th and 34th weeks. To assess fetal heart growth, we used the XI VOCAL software with 10 planes in which the reference lines (beginning and end) were placed at the cardiac apex, the output level of the vessels and the base above the diaphragm, respectively. To assess the correlation between distance and interval, polynomial regressions were performed with adjustments using the coefficient of determination (R²). To assess the inter-observer reproducibility, we used the intraclass correlation coefficient (ICC).

Results: The mean distance between the apex and the base of the fetal heart ranged from 14.41?±?1.24?mm to 26.24?±?2.62?mm between the 20th and 34th weeks, respectively. The mean interval between the apex and the base of the fetal heart ranged from 1.56?±?0.13?mm and 2.94?±?0.30?mm between the 20th and 34th weeks, respectively. We observed good correlation of distance and interval with the gestational age, with R²?=?0.73 and 0.74, respectively. We observed a good inter-observer to the interval and distance with ICC?=?0.983 and 0.996, respectively.

Conclusion: We described a new technique for assessing fetal heart growth using 3DUS and determined reference curves for the distance and interval between the 20th and 34th weeks of pregnancy.