Division of Fetal Imaging, Department of Obstetrics and Gynecology, William Beaumont Hospital Royal Oak, MI 48073-6769, USA.
Ultrasound Obstet Gynecol. 2009 Apr;33(4):427-40. doi: 10.1002/uog.6319.
The main goals were to provide normal reference ranges for fractional limb volume as a new index of generalized fetal nutritional status, to evaluate the reproducibility of fractional fetal limb volume measurements during the second and third trimesters of pregnancy, and to demonstrate technical considerations for this technique.
This was a prospective, cross-sectional study of gravid women during mid to late pregnancy. Fractional limb volumes were based on either 50% of humeral or femoral diaphysis length. Each partial volume was subdivided into five equidistant slices that were centered along the mid-arm or mid-thigh. Slices were traced manually to obtain fractional arm (AVol) or fractional thigh (TVol) volume. Reproducibility studies were performed, using Bland-Altman plots, to assess blinded interobserver and intraobserver measurement bias and agreement. Selected images were chosen to demonstrate technical factors for the acquisition and analysis of these parameters. Reference charts were established to describe normal ranges for AVol and TVol.
Three hundred and eighty-seven subjects were scanned to include 380 AVol (range, 1.1-68.3 mL) and 378 TVol (range 2.0-163.2 mL) measurements between 18.0 and 42.1 weeks' menstrual age. No gender differences were found in these soft tissue measurements (AVol, P = 0.90; TVol, P = 0.91; Mann-Whitney test). Intraobserver mean bias +/- SD and 95% limits of agreement (LOA) for fractional limb volumes were: 2.2 +/- 4.2% (95% LOA, - 6.0 to 10.5%) for AVol and 2.0 +/- 4.2% (95% LOA, - 6.3 to 10.3%) for TVol. Interobserver bias and agreement were - 1.9 +/- 4.9% (95% LOA, - 11.6 to 7.8%) for AVol and - 2.0 +/- 5.4% (95% LOA, - 12.5 to 8.6%) for TVol. Technical factors were related to image optimization, transducer pressure, fetal movement, soft tissue compression and amniotic fluid volume.
Fractional limb volume assessment may improve the detection and monitoring of malnourished fetuses because this soft tissue parameter can be obtained quickly and reproducibly during mid to late pregnancy. Careful attention should be placed on technical factors that can potentially affect optimal acquisition and analysis of these volume measurements.
本研究旨在提供胎儿肢体体积比作为一种新的胎儿整体营养状况指标的正常参考范围，评估妊娠中期和晚期胎儿肢体体积比测量的可重复性，并展示该技术的技术要点。
这是一项前瞻性、横断面研究，纳入妊娠中期和晚期的孕妇。肢体体积比基于肱骨或股骨骨干的 50%长度。每个部分体积被细分为五个等分的切片，沿着上臂或大腿中部居中。通过手动描绘切片来获得上肢（AVol）或下肢（TVol）的体积。采用 Bland-Altman 图进行重复性研究，以评估盲法观察者内和观察者间测量偏倚和一致性。选择了一些图像来展示获得和分析这些参数的技术要点。建立参考图表以描述 AVol 和 TVol 的正常范围。
在 18.0 至 42.1 周的月经龄期间，对 387 例孕妇进行了扫描，包括 380 个 AVol（范围 1.1-68.3mL）和 378 个 TVol（范围 2.0-163.2mL）测量值。在这些软组织测量中，未发现性别差异（AVol，P=0.90；TVol，P=0.91；Mann-Whitney 检验）。肢体体积比的观察者内平均偏倚±SD 和 95%一致性界限（LOA）为：AVol 为 2.2%±4.2%（95% LOA，-6.0 至 10.5%），TVol 为 2.0%±4.2%（95% LOA，-6.3 至 10.3%）。观察者间偏倚和一致性为 AVol 的-1.9%±4.9%（95% LOA，-11.6 至 7.8%）和 TVol 的-2.0%±5.4%（95% LOA，-12.5 至 8.6%）。技术因素与图像优化、换能器压力、胎儿运动、软组织压缩和羊水体积有关。
胎儿肢体体积比评估可能会提高营养不良胎儿的检测和监测能力，因为该软组织参数可以在妊娠中期和晚期快速、可重复地获得。应注意可能影响这些体积测量最佳获取和分析的技术因素。
