Fetal and Maternal Medicine Department, Nottingham University Hospitals NHS Trust, Nottingham, UK.
Ultrasound Med Biol. 2012 Jan;38(1):69-74. doi: 10.1016/j.ultrasmedbio.2011.10.016. Epub 2011 Nov 21.
The objective was to assess interobserver reliability of fetal head biometry using archived three-dimensional (3-D) volumes and the impact of gestational age and presence of brain anomalies on examiners' performance. Seventy nine 3-D volume datasets of fetal head were examined: 27 were normal and 52 had brain abnormalities. Off-line analysis was done by three fetal medicine experts (E1, E2 and E2), all were blinded to history and patient details. Measurements of the biparietal diameter (BPD), head circumference (HC), lateral ventricle (Vp) and transcerebellar diameter (TCD) were compared between examiners and to two-dimensional (2-D) measurements. Comparisons were made at two gestational age groups (≤22 and >22 weeks) and in presence and absence of brain anomalies. The intraclass coefficient showed a significantly high level of measurement agreement between 3-D examiners and 2-D, with values >0.9 throughout (p < 0.001). Bias was evident between 3-D examiners. E2 produced smaller measurements. The mean percentage difference between this examiner and the other two in BPD, HC, Vp and TCD measurements was significant, of 1.6%, 1%, 4.9% and 1.8%, respectively. E1 measured statistically larger for HC and TCD. E3 measured significantly larger for only BPD. The presence of anomalies was of no influence on the 3-D examiners' performance except for E3 who showed bias in BPD measurements only in cases with brain anomalies. Unlike other examiners, bias of E2 was only seen at gestational age group ≤22 weeks. Limits of agreement in measurements between observers were narrow for all parameters but were widest for the Vp measurements, being ±23% of the mean difference. Despite the above bias, the actual mean difference between examiners was small and unlikely to be of any clinical significance. Off-line measurement of fetal head biometry using 3-D volumes is reliable. In our study, presence of brain anomalies was unlikely to influence the reproducibility of measurements. Gestational age seemed to be of an impact on examiners' bias. Among experts this bias may be of no clinical significance.
目的是评估使用存档的三维（3-D）体积进行胎儿头部生物测量的观察者间可靠性，以及胎龄和脑异常对检查者表现的影响。检查了 79 个胎儿头部的 3-D 体积数据集：27 个正常，52 个有脑异常。离线分析由 3 位胎儿医学专家（E1、E2 和 E2）进行，他们均对病史和患者细节不知情。比较了检查者之间以及与二维（2-D）测量之间的双顶径（BPD）、头围（HC）、侧脑室（Vp）和小脑横径（TCD）的测量值。比较了两个胎龄组（≤22 周和>22 周）和存在或不存在脑异常时的情况。组内相关系数显示 3-D 检查者与 2-D 之间的测量一致性具有显著的高水平，所有值均>0.9（p<0.001）。3-D 检查者之间存在偏差。E2 产生的测量值较小。在 BPD、HC、Vp 和 TCD 测量值中，该检查者与其他两位检查者的平均百分比差异分别为 1.6%、1%、4.9%和 1.8%，差异显著。E1 测量的 HC 和 TCD 统计学上较大。E3 仅在 BPD 测量中显著更大。脑异常对 3-D 检查者的表现没有影响，除了 E3，他在仅存在脑异常的情况下显示出 BPD 测量的偏差。与其他检查者不同，E2 的偏差仅在胎龄组≤22 周时出现。观察者之间测量值的一致性限很窄，但 Vp 测量值最宽，为平均差值的±23%。尽管存在上述偏差，但检查者之间的实际平均差异很小，不太可能具有任何临床意义。使用 3-D 体积对胎儿头部生物测量进行离线测量是可靠的。在我们的研究中，脑异常的存在不太可能影响测量的可重复性。胎龄似乎对检查者的偏差有影响。在专家中，这种偏差可能没有临床意义。
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