COMPARATIVE ANALYSIS OF THE ACCURACY OF ULTRASONOGRAPHY AND MAGNETIC RESONANCE IMAGING IN ESTIMATING FETAL WEIGHT

Objective: To compare the accuracy of ultrasonography (USG) and magnetic resonance imaging (MRI) in determining estimated fetal weight (EFW). Materials and methods: This prospective study included 103 pregnant women who underwent both MRI and USG before delivery. The EFW based on MRI data was calculated using the formula by Baker et al., while the EFW based on USG data was calculated using the Hadlock et al. formula. The EFW values were assessed using absolute measurements and on a percentile scale (INTERGROWTH-21st). Results: The correlation coefficient between EFW based on USG data and the newborn's birth weight was 0.831 (p<0.001), while for MRI, it was 0.941 (p<0.001). The mean absolute error (MAE) of EFW in absolute values for USG was 145.68 (427.42) g, and for MRI, it was 117.83 (221.98) g, on a percentile scale, the MAE for USG was 4.17 (15.68), for MRI, it was 3.16 (7.03). The correlation coefficient between EFW above the 90th percentile was 0.374 (p=0.041) for USG and 0.855 (p<0.001) for MRI. The MAE for determining EFW (>90th percentile) was 173.93 (432.16) g for USG and 122.0 (202.82) g for MRI. On a percentile scale, the MAE was 0.38 (6.07) for USG and 0.76 (2.56) for the MRI. The area under the curve (ROC AUC) for identifying cases with birth weights > 4000 g was 0.916 (95% CI: 0.860–0.973) for USG and 0.986 (95% CI: 0.967–1.000) for MRI. Conclusion: EFW determination based on MRI data is more accurate than that based on USG data, with the most significant differences noted in cases of fetal macrosomia. Developing machine learning algorithms is essential to reduce the time required for segmenting areas of interest, thereby enhancing the role of artificial intelligence in automating the EFW determination processes. Further research is necessary to establish the optimal timing and indications for using MRI as an additional method for determining the EFW. © 2025 Elsevier B.V., All rights reserved.