Oehme Ninnie Helén Bakken, Roelants Mathieu, Bruserud Ingvild Særvold, Eide Geir Egil, Bjerknes Robert, Rosendahl Karen, Júlíusson Pétur B
Department of Clinical Science, University of Bergen, N-5020, Bergen, Norway.
Department of Pediatrics, Haukeland University Hospital, Bergen, Norway.
Pediatr Radiol. 2018 Nov;48(12):1771-1778. doi: 10.1007/s00247-018-4195-8. Epub 2018 Jul 6.
Prader orchidometry has been the standard method for evaluating testicular size. As this technique is subjective and tends to overestimate the testicular volume, ultrasound (US) has been proposed as more reliable.
To evaluate the intra- and interobserver agreement of US measurements of testicular volume and to compare US with the Prader orchidometer.
Dimensions of the right testicle were measured using US in 57 boys ages 6.5 to 16.4 years (mean: 12.0 years). The measurements were performed twice by one main observer and once by a second observer. A third observer estimated testicular volume using a Prader orchidometer. Agreement was investigated with Bland-Altman plots, summarized as the mean and standard deviation (SD) of differences, 95% limits of agreement and technical error of measurement.
Mean intra-observer difference of testicular volume was 2.2%, SD=9.2% (limits of agreement: -20.3 to 15.9%) and technical error of measurement 6.5%. The mean interobserver difference was 4.8%, SD=20.7% (limits of agreement: -35.7 to 45.3%) and technical error of measurement 14.6%. Comparing US and orchidometer volumes required conversion that was nonlinear and volume dependent, estimated as Vol = 1.96×Vol. The mean difference after transformation was 0.7% with an SD of 18.0% (limits of agreement: -34.5 to 35.9%).
Our results showed a small mean intra- and interobserver difference that indicates the potential of US for measurement of testicular volume at group level. The intra-observer error was limited, which justifies its use in longitudinal follow-up of testicular development in an individual child, but the larger interobserver variability indicates the need for good standardization of methods. Agreement between the two methods requires a power transformation.
普拉德睾丸测量法一直是评估睾丸大小的标准方法。由于该技术主观且往往高估睾丸体积，超声检查已被认为更为可靠。
评估超声测量睾丸体积的观察者内和观察者间一致性，并将超声与普拉德睾丸测量器进行比较。
对57名年龄在6.5至16.4岁（平均12.0岁）的男孩使用超声测量右侧睾丸的尺寸。由一名主要观察者进行两次测量，另一名观察者进行一次测量。第三名观察者使用普拉德睾丸测量器估计睾丸体积。通过布兰德-奥特曼图研究一致性，总结为差异的均值和标准差（SD）、95%一致性界限和测量技术误差。
观察者内睾丸体积的平均差异为2.2%，SD = 9.2%（一致性界限：-20.3%至15.9%），测量技术误差为6.5%。观察者间的平均差异为4.8%，SD = 20.7%（一致性界限：-35.7%至4).3%），测量技术误差为14.6%。比较超声和睾丸测量器的体积需要进行非线性且依赖于体积的转换，估计为Vol = 1.96×Vol。转换后的平均差异为0.7%，SD为18.0%（一致性界限：-34.5%至35.9%）。
我们的结果显示观察者内和观察者间的平均差异较小，表明超声在群体水平上测量睾丸体积的潜力。观察者内误差有限，这证明了其在个体儿童睾丸发育纵向随访中的应用合理性，但较大的观察者间变异性表明需要对方法进行良好的标准化。两种方法之间的一致性需要进行幂转换。
