“NT手动测量与半自动测量超声检查者自身及检查者之间的可重复性：一项交叉研究”点评

陈佩文 陈欣林 赵胜 杨小红

(湖北省妇幼保健院超声诊断科，湖北武汉 430070)

1 原文摘要

ObjectiveThe goal of this study was to examine the intra-operator and inter-operator differences of the manual and semiautomated nuchal translucency(NT)measurements and to evaluate if these differences alter women's risk status．

Methods A cross sectional study was performed．Two operators obtained manual and semiautomated NT measurements of 153 NT images．The maximal acceptable difference in NT measurements within and between operators was 0．15?mm．Intra and interoperator differenceswere analyzed by the paired Student'st-test and homogeneity of variances by the Levene's test．Intra-operator and inter-operator agreement were quantified with Bland and Altman's limits of agreement，and changes in women's risk status were tested with the binomial test．

ResultsIntra-operator agreement was high for each of the measurement methods．Operator 1 had lower SDS for manual measurements．Conversely，operator 2 had lower SDS of the differences for semiautomated measurements，although the SD never reached the same level as operator 1．Inter-operator agreement was highest for the semiautomated measurements．Changes in risk status occurred between the manual and innermiddle method resulting in different clinical policies in up to 1 out of 20 cases．

Conclusion Well-trained operators do not seem to benefit from the use of the semiautomated measurement methods．

2 论文核心内容及点评

该文章2013年12月发表于《Prenatal Diagnosis》杂志上。在该研究中，作者通过观察手动和半自动两种方法测量胎儿颈项皮肤厚度(NT)，不同的方法及检查者自身和检查者之间的测量差异，评估这些差异是否影响或改变孕妇胎儿染色体异常风险的判定。主要内容如下：

这是一项交叉性的研究。2位检查者对153幅已经获得的NT图像进行手动和半自动NT测量。检查者自身及两位检查者之间的最大可接受的差值为0．15毫米。应用成对t检验对检查者自身及两位检查者之间差异进行配对分析，应用Levene检验方差齐性，应用Bland and Altman's置信区间对检查者自身及两位检查者之间一致性进行量化，应用二项式检验评估差值是否改变妇女的风险状况。

检查者本人应用每一种方法进行NT值的测量具有高度的一致性。检查者1应用手动测量时，其标准差差值较低。反之，检查者2应用半自动测量，其标准差差值较低，虽然标准差未达到检查者1的水平，但半自动测量时检查者间的一致性达到最高。由于手动测量和内-中线的测量差异导致高达有1/20的病例风险状态发生变化。由此作者认为，富有经验的超声检查者似乎并不能从NT的半自动测量方法中获益。

NT值的测量是筛查染色体异常及胎儿结构缺陷最有效的标志，为使不同操作者的结果达到一致性，必须坚持标准的测量技术。在NT的测量中，有胎儿图像的质量及测量键放置能导致操作者的偏差，增加了测量的变异性。有研究表明对给定的图像进行NT值测量的过程中，半自动测量能潜在的消除绝大多数操作者间的变异并实质性地减少操作者自身的测量变异。本研究不仅将两种方法及不同测量者进行交叉性比较，从而得出半自动测量更适宜NT的初学者或是经验不足的超声检查者。对于指导我们临床有一定的实用价值。同时，由于新的方法所导致孕妇风险状态的改变，是否提示我们应制定半自动测量相应风险值，这是值得我们进一步关注的。