Pretorius D H, Nelson T R, Manco-Johnson M L
Radiology. 1984 Sep;152(3):763-6. doi: 10.1148/radiology.152.3.6463258.
Ultrasound estimation of fetal age is a routine, safe, and valuable diagnostic procedure. The overall accuracy of ultrasound measurement of femur length and biparietal diameter was investigated using a dowel phantom, chicken bones, and a bottle. Objects were imaged in a water bath using commercially available static, linear, and sector scanners. Transducer type and frequency, depth, object dimension, and observer variation were evaluated. Our results show that there was no appreciable difference between transducer types; the overall accuracy of the measurements improved with increasing transducer frequency; the lateral measurements consistently overestimated the object length; the absolute error in lateral measurements was between 0-12 mm; the absolute error in axial measurements was between 0-4 mm; the interobserver variability was +/- 1.3 mm, and intraobserver variability was +/- 1.0 mm. We conclude that transducer type does not affect measurement accuracy, measurement errors are greater in the lateral dimension as opposed to the axial dimension, proper quality assurance and performance evaluation procedures are necessary to ensure optimal results, and femur length measurements will continue to be useful in evaluation of gestational age.
超声估算胎儿年龄是一项常规、安全且有价值的诊断程序。使用定位销模型、鸡骨和瓶子研究了超声测量股骨长度和双顶径的总体准确性。使用市售的静态、线性和扇形扫描仪在水浴中对物体进行成像。评估了换能器类型和频率、深度、物体尺寸以及观察者差异。我们的结果表明，换能器类型之间没有明显差异；测量的总体准确性随着换能器频率的增加而提高；横向测量始终高估物体长度；横向测量的绝对误差在0至12毫米之间；轴向测量的绝对误差在0至4毫米之间；观察者间的变异性为±1.3毫米，观察者内的变异性为±1.0毫米。我们得出结论，换能器类型不影响测量准确性，横向维度的测量误差大于轴向维度，需要适当的质量保证和性能评估程序以确保获得最佳结果，并且股骨长度测量在评估孕周方面仍将有用。
