Department of Obstetrics, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil.
Prenat Diagn. 2011 Dec;31(13):1234-40. doi: 10.1002/pd.2870. Epub 2011 Oct 26.
To provide reference values for fetal thigh volume using three-dimensional (3D) ultrasound and the eXtended Imaging Virtual Organ Computer-aided AnaLysis (XI VOCAL) method.
This is a cross-sectional study that enrolled 425 healthy pregnant women between the 20(th) and 40(th) weeks of gestation. The XI VOCAL was performed along the axial cross-section in ten sequential areas for the volumetric calculations, having the proximal and distal echogenic diaphysis as references. Second-degree polynomial regression models, with the determination of percentiles, were created to evaluate the relation between the fetal thigh volume and gestational age (GA). Intraoperator and interoperator reproducibility was evaluated using intraclass correlation coefficient.
The mean fetal thigh volume varied from 8.00 (3.90-11.90 cm(3) ) to 122.14 cm(3) (105.0-153.50 cm(3) ) at 20 and 40 weeks of gestation, respectively. Fetal thigh volume was strongly correlated with gestational age, and the reference values can be obtained by the following mathematical equation: fetal thigh volume (cm(3) ) = 68.70-7.63 × GA + 0.23 × GA(2) (R(2) = 0.946). The intraoperator and interoperator reproducibility were excellent, with an intraclass correlation coefficient = 1.000 and 0.999, respectively.
The reference range of fetal thigh volume was determined by 3D-ultrasound using the XI VOCAL method.
利用三维（3D）超声和 eXtended Imaging Virtual Organ Computer-aided AnaLysis（XI VOCAL）方法，为胎儿大腿体积提供参考值。
这是一项横断面研究，共纳入 425 名妊娠 20 至 40 周的健康孕妇。通过轴向横切面，在十个连续区域进行 XI VOCAL 以进行体积计算，近端和远端回声骨干作为参考。创建二次多项式回归模型，确定百分位数，以评估胎儿大腿体积与胎龄（GA）之间的关系。使用组内相关系数评估操作者内和操作者间的可重复性。
20 至 40 周时，胎儿大腿体积平均值分别为 8.00（3.90-11.90cm3）至 122.14cm3（105.0-153.50cm3）。胎儿大腿体积与胎龄呈强相关，可通过以下数学方程获得参考值：胎儿大腿体积（cm3）=68.70-7.63×GA+0.23×GA2（R2=0.946）。操作者内和操作者间的可重复性均很好，组内相关系数分别为 1.000 和 0.999。
使用 3D 超声和 XI VOCAL 方法确定了胎儿大腿体积的参考范围。
