Ioannou Christos, Sarris Ippokratis, Napolitano Raffaele, Ohuma Eric, Javaid M Kassim, Papageorghiou Aris T
Nuffield Department of Obstetrics & Gynaecology, University of Oxford, UK.
Prenat Diagn. 2013 Nov;33(11):1088-94. doi: 10.1002/pd.4203. Epub 2013 Aug 23.
Fetal femur volume (FV) is a useful marker of skeletal growth. Our objective was to create a normal FV chart in a cohort of healthy pregnant women and to assess FV repeatability.
The method used was a prospective, observational study using 3D ultrasound. Low-risk pregnant women underwent serial scans from 14 to 42 weeks. Strict inclusion and exclusion criteria were used in order to remove pathological conditions. Pregnancies were dated by last menstrual period and confirmed by crown-rump length. FV was measured using three linear measurements and a volume equation. Data were analyzed using multilevel modeling. Repeatability was assessed using within-subject coefficients of variation (CV), intraclass correlation coefficients (ICC), and Bland-Altman plots.
A total of 180 women underwent 868 scans, a median of five scans per participant. Median and centile values were presented in the form of curves, regression equations, and table of values per completed week. Intra-observer CV and ICC were 10.5% and 0.977, respectively; interobserver CV and ICC were 16.8% and 0.923.
This normal FV chart can be used as a prescriptive standard in order to assess fetal skeletal growth. Measurement repeatability is satisfactory for clinical use, but FV has a larger random error than commonly seen with standard 2D biometry.
胎儿股骨体积（FV）是骨骼生长的一个有用指标。我们的目的是建立一组健康孕妇的正常FV图表，并评估FV的可重复性。
所采用的方法是一项使用三维超声的前瞻性观察性研究。低风险孕妇在孕14至42周期间接受系列扫描。使用严格的纳入和排除标准以排除病理情况。根据末次月经日期确定孕周，并通过头臀长进行确认。使用三个线性测量值和一个体积公式来测量FV。使用多水平模型分析数据。使用受试者内变异系数（CV）、组内相关系数（ICC）和Bland-Altman图评估可重复性。
共有180名女性接受了868次扫描，每位参与者的扫描次数中位数为5次。中位数和百分位数以曲线、回归方程以及每完整孕周的数值表形式呈现。观察者内CV和ICC分别为10.5%和0.977；观察者间CV和ICC分别为16.8%和0.923。
这个正常FV图表可作为一个规范性标准，用于评估胎儿骨骼生长。测量的可重复性对于临床应用而言是令人满意的，但FV的随机误差比常见的标准二维生物测量法更大。
