Matthew Jacqueline, Skelton Emily, Story Lisa, Davidson Alice, Knight Caroline L, Gupta Chandni, Pasupathy Dharmintra, Rutherford Mary
School of Biomedical Engineering and Imaging Sciences and School of Life Course Sciences, Faculty of Life Sciences in Medicine, King's College London, London, United Kingdom.
Guy's & St. Thomas' NHS Foundation Trust, London, United Kingdom.
Fetal Diagn Ther. 2021;48(10):708-719. doi: 10.1159/000519115. Epub 2021 Nov 17.
The aim of this study was to compare the standard ultrasound (US) estimated fetal weight (EFW) and MRI volume-derived methods for the midtrimester fetus.
Twenty-five paired US and MRI scans had the EFW calculated (gestational age [GA] range = 20-26 weeks). The intra- and interobserver variability of each method was assessed (2 operators/modality). A small sub-analysis was performed on 5 fetuses who were delivered preterm (mean GA 29 +3 weeks) and compared to the actual birthweight.
Two MRI volumetry EFW formulae under-measured compared to US by -10.9% and -14.5% in the midpregnancy fetus (p < 0.001) but had excellent intra- and interobserver agreement (intraclass correlation coefficient = 0.998 and 0.993). In the preterm fetus, the mean relative difference (MRD) between the MRI volume-derived EFW (MRI-EFW) and actual expected birthweight (at the scan GA) was -13.7% (-159.0 g, 95% CI: -341.7 to 23.7 g) and -17.1% (-204.6 g, 95% CI: -380.4 to -28.8 g), for the 2 MRI formulae. The MRD was smaller for US at 5.3% (69.8 g, 95% CI: -34.3 to 173.9).
MRI-EFW results should be interpreted with caution in midpregnancy. Despite excellent observer agreement with MRI volumetry, refinement of the EFW formula is needed in the second trimester, for the small and for the GA and preterm fetus to compensate for lower fetal densities.
本研究旨在比较标准超声（US）估计的胎儿体重（EFW）与孕中期胎儿的MRI体积推导法。
对25对US和MRI扫描进行了EFW计算（孕周[GA]范围=20-26周）。评估了每种方法的观察者内和观察者间变异性（2名操作者/检查方式）。对5例早产胎儿（平均GA 29 +3周）进行了小样本亚分析，并与实际出生体重进行比较。
与US相比，两种MRI容积法EFW公式在孕中期胎儿中测量值偏低，分别低10.9%和14.5%（p<0.001），但观察者内和观察者间一致性良好（组内相关系数=0.998和0.993）。在早产胎儿中，两种MRI公式的MRI体积推导EFW（MRI-EFW）与实际预期出生体重（扫描时GA）之间的平均相对差异（MRD）分别为-13.7%（-159.0 g，95%CI：-341.7至23.7 g）和-17.1%（-204.6 g，95%CI：-380.4至-28.8 g）。US的MRD较小，为5.3%（69.8 g，95%CI：-34.3至173.9）。
孕中期MRI-EFW结果应谨慎解释。尽管MRI容积法观察者一致性良好，但在孕中期仍需要改进EFW公式，以适用于小胎儿、不同孕周胎儿及早产胎儿，以补偿较低的胎儿密度。
