Kadji Caroline, Camus Margaux F, Bevilacqua Elisa, Cannie Mieke M, Sanchez Teresa Cos, Jani Jacques C
Department of Obstetrics and Gynecology, University Hospital Brugmann, Université Libre de Bruxelles, Brussels, Belgium.
Department of Radiology, University Hospital Brugmann, Université Libre de Bruxelles, Brussels, Belgium; Department of Radiology, UZ Brussel, Vrije Universiteit Brussel, Brussels, Belgium.
Eur J Radiol. 2017 Jun;91:35-40. doi: 10.1016/j.ejrad.2017.03.005. Epub 2017 Mar 21.
Our aim was to evaluate the intra- and inter-observer variability and the impact of operator experience on the estimation of fetal weight (EFW) as measured by 2-dimensional ultrasound (2D-US) and magnetic resonance (MR) imaging.
We estimated fetal weight in 46 singleton pregnancies at 35.6-41.4 weeks gestation using 2D-US according to the Hadlock formula and using MR imaging according to the equation developed by Baker. Each examination was performed twice, once by an inexperienced operator and once by an experienced operator. The MR-EFW was derived from the planimetric measurement of fetal body volume (FBV) using an assisted semi-automated method. Intra- and inter-observer variability was evaluated by Bland-Altman analysis. Regression analysis was used to investigate the effect of maternal BMI, delivery weight, diabetes and fetal gender on the differences in US-EFW between the inexperienced and experienced operators.
US-EFW showed higher intra-observer variability than MR-EFW, irrespective of operator experience. The 95% limits of agreement of MR were narrower compared with those of the US measurements. Similarly, US-EFW showed higher inter-observer variability than MR-EFW. MR-EFW improvement over 2D-US for the limits of agreement was 77.9% for intra-observer variability and 74.5% for inter-observer variability. Regression analysis showed that the differences between US-EFW measurements were not related to any of the tested variables.
Operator experience has a marginal impact on the variability of US-EFW and no impact on MR-EFW variability. The variability in US-EFW measurements is unpredictable.
我们的目的是评估二维超声（2D-US）和磁共振成像（MR）测量胎儿体重（EFW）时观察者内和观察者间的变异性以及操作者经验的影响。
我们对46例单胎妊娠、孕周在35.6 - 41.4周的孕妇，根据哈德洛克公式用2D-US估算胎儿体重，根据贝克开发的公式用MR成像估算胎儿体重。每次检查由一名无经验的操作者和一名有经验的操作者各进行两次。MR-EFW通过使用辅助半自动方法对胎儿身体体积（FBV）进行平面测量得出。通过布兰德-奥特曼分析评估观察者内和观察者间的变异性。采用回归分析研究孕妇体重指数、分娩体重、糖尿病和胎儿性别对无经验和有经验操作者之间US-EFW差异的影响。
无论操作者经验如何，US-EFW的观察者内变异性均高于MR-EFW。与US测量相比，MR的95%一致性界限更窄。同样，US-EFW的观察者间变异性也高于MR-EFW。对于一致性界限，MR-EFW相对于2D-US在观察者内变异性方面的改善为77.9% , 在观察者间变异性方面为74.5%。回归分析表明，US-EFW测量值之间的差异与任何测试变量均无关。
操作者经验对US-EFW的变异性影响较小，对MR-EFW的变异性无影响。US-EFW测量的变异性不可预测。
