Department of Obstetrics and Gynecology, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla 90110, THAILAND.
BMC Pregnancy Childbirth. 2013 Jan 16;13:7. doi: 10.1186/1471-2393-13-7.
Nasal bone assessment has been incorporated into Down syndrome screening in first trimester. Several studies have established the normal reference values for fetal nasal bone length in the first trimester, which were found to be varied by population. However, the study on reliability of nasal bone length measurement was limited with contradictory results. This study aimed to investigate the reliability of fetal nasal bone length measurement at 11-14 weeks of gestation in the Thai population.
A total of 111 pregnant women at 11-14 weeks of gestation attending for the routine first-trimester ultrasound examination were recruited. Each case was measured separately by two examiners. Examiner 1 performed the first measurement in all cases; any of the other 5 examiners consecutively performed the second measurement. Three independent measurements were performed by each examiner and they were blinded to the results of the others. Intraobserver and interobserver variabilities were evaluated with the intraclass correlation coefficient (ICC).
Nasal bone measurement was successfully performed in 106/111 cases (95.5%) by at least one examiner; 89 cases were performed by two examiners. The intraobserver variability was excellent for all examiners (ICC, 0.840-0.939). The interobserver variability between different pairs of examiners varied from moderate to excellent (ICC, 0.467-0.962). The interobserver variability between examiner 1 and any other examiner was good (ICC, 0.749). The Bland-Altman plot of the interobserver differences of nasal bone length measurements between examiner 1 and any other examiner showed good agreement.
The reliability of the fetal nasal bone length measurement at 11-14 weeks of gestation was good. The nasal bone length measurement was reproducible. Ethnicity has an effect on fetal nasal bone length, but reliability of nasal bone length measurement is critical to accuracy of screening and should be audited on an ongoing basis.
鼻骨评估已纳入早孕期唐氏综合征筛查。多项研究已确定了早孕期胎儿鼻骨长度的正常参考值，这些值因人群而异。然而，关于鼻骨长度测量可靠性的研究有限，结果存在矛盾。本研究旨在探讨泰国人群中 11-14 孕周胎儿鼻骨长度测量的可靠性。
共招募 111 名 11-14 孕周的孕妇进行常规早孕期超声检查。每位孕妇均由两名检查者分别进行测量。检查者 1 对所有病例进行首次测量；其他 5 名检查者中的任何一名连续对第二次测量进行操作。每位检查者进行了 3 次独立测量，且他们对其他人的结果均不知情。采用组内相关系数（ICC）评估观察者内和观察者间的可重复性。
至少有一名检查者成功完成了 106/111 例（95.5%）的鼻骨测量；89 例由两名检查者完成。所有检查者的观察者内可重复性均较好（ICC 为 0.840-0.939）。不同检查者对之间的观察者间可重复性从中等至较好（ICC 为 0.467-0.962）。检查者 1 与任何其他检查者之间的观察者间可重复性良好（ICC 为 0.749）。检查者 1 与任何其他检查者之间的鼻骨长度测量的观察者间差异的 Bland-Altman 图显示出良好的一致性。
11-14 孕周胎儿鼻骨长度测量的可靠性良好。鼻骨长度测量具有可重复性。种族对胎儿鼻骨长度有影响，但鼻骨长度测量的可靠性对筛查的准确性至关重要，应持续进行审核。
