Delta-Ultrasound Diagnostic Center in Obstetrics and Gynecology, Madrid, Spain.
Ultrasound Obstet Gynecol. 2014 Mar;43(3):272-6. doi: 10.1002/uog.12525. Epub 2014 Feb 9.
To examine the feasibility and accuracy of fetal nasal bone (NB) assessment in the retronasal triangle (RNT) view for aneuploidy screening in the first trimester of pregnancy.
Consecutive women with singleton pregnancies undergoing sonographic screening at 11-13 weeks' gestation were prospectively evaluated. In all cases, assessment of the NB by using the RNT view was attempted and classified as present (if one or both of the NBs were clearly seen) or absent/hypoplastic (if the NB was not visualized or if it was small and less echogenic than the surrounding bones). The detection rate of fetal karyotypic abnormalities by the assessment of the NB in the RNT view was calculated.
In total, 1977 women were scanned. The RNT was successfully examined in 1970 fetuses (99.6%). Fetal outcome was available in 1767 (89.7%) of evaluated cases, and of these, 39 (2.2%) cases of aneuploidy were documented (trisomy 21, n=17; trisomy 18, n=8; trisomy 13, n=5; Turner syndrome, n=5; and triploidy, n=4). The prevalence of absent/hypoplastic NB was 12/1728 (0.7%) in chromosomally normal fetuses and 12/17 (70.6%) in trisomy 21 fetuses. Sensitivity, specificity and positive and negative predictive values of absent/hypoplastic NB for trisomy 21 were 70.6%, 99.3%, 50.0% and 99.7%, respectively. The positive and negative likelihood ratios of NB assessment were 101 (95% CI, 53-193) and 0.3 (95% CI, 0.14-0.62), respectively.
The RNT view is a useful technique for assessing the NB during the first trimester of pregnancy. With this new approach, performance of absent/hypoplastic NB as a marker of aneuploidy, mainly trisomy 21, appears to be similar to that previously reported by using the mid-sagittal plane.
探讨在妊娠早期经颅后窝三角（RNT）切面评估胎儿鼻骨（NB）用于筛查非整倍体的可行性和准确性。
前瞻性评估连续 11-13 孕周接受超声筛查的单胎妊娠孕妇。所有病例均尝试采用 RNT 切面评估 NB，分为存在（若能清晰显示 1 个或 2 个 NB）或不存在/发育不良（若 NB 无法显示或 NB 小且回声低于周围骨骼）。计算 RNT 切面评估 NB 对胎儿染色体异常的检出率。
共 1977 例孕妇接受了扫描。1970 例胎儿（99.6%）RNT 成功检查。1767 例（89.7%）评估病例可获得胎儿结局，其中 39 例（2.2%）证实为非整倍体（21 三体 17 例，18 三体 8 例，13 三体 5 例，特纳综合征 5 例，三倍体 4 例）。正常染色体胎儿中 NB 缺失/发育不良的发生率为 12/1728（0.7%），21 三体胎儿中为 12/17（70.6%）。NB 缺失/发育不良对 21 三体的敏感性、特异性、阳性预测值和阴性预测值分别为 70.6%、99.3%、50.0%和 99.7%。NB 评估的阳性和阴性似然比分别为 101（95%CI，53-193）和 0.3（95%CI，0.14-0.62）。
RNT 切面是妊娠早期评估 NB 的一种有用技术。采用这种新方法，NB 缺失/发育不良作为非整倍体，特别是 21 三体的标志物的表现与既往报道的经正中矢状切面的结果相似。
