Department of Prenatal Medicine and Gynecologic Ultrasound, University of Basel, Women's Hospital, Spitalstrasse 21, 4031, Basel, Switzerland.
Department of Obstetrics and Gynecology, Institute of Ultrasound, Sackler School of Medicine, Assaf Harofeh Medical Centre, Beer Yakov 70300, Tzrifin, Israel.
Arch Gynecol Obstet. 2019 Apr;299(4):939-945. doi: 10.1007/s00404-019-05083-2. Epub 2019 Feb 9.
To perform a multicenter prospective study of ultrasound prenasal thickness (PT), and nasal bone length (NBL) measurement at 11-14 weeks' gestation.
Ultrasound PT and NBL determination was performed in 504 normal fetuses and 17 fetuses with Down's syndrome (DS). Measurements were made from mid-sagittal 2D images acquired using a standardized technique during nuchal translucency (NT) examination. PT and NBL values were expressed in multiples of the gestation-specific normal median (MoM) and as the PT/NBL ratio. Information on PT and NBL MoMs was also combined using logistic regression. Results were classified as positive according to whether they were greater than the normal 95th centile for PT, PT/NBL and the DS risk from logistic regression equation or below the 5th centile for NBL.
The median value in DS cases and unaffected controls were: PT 1.26 and 0.996 MoM; and NBL 0.596 and 0.993 MoM. The proportion of DS fetuses with positive results was 41% for PT, 65% for NBL, and 82% for both the PT/NBL ratio and DS risk from the logistic regression equation. PT/NBL levels did not vary according to gestational age.
The PT/NBL ratio is a valuable first trimester DS screening marker that can be easily determined concomitant with the NT measurement.
对孕 11-14 周经阴道超声测量胎儿鼻骨长度（NBL）和鼻前软组织厚度（PT）进行多中心前瞻性研究。
对 504 例正常胎儿和 17 例唐氏综合征（DS）胎儿进行超声 PT 和 NBL 测定。采用标准技术在颈项透明层（NT）检查时获取正中矢状面 2D 图像，进行测量。PT 和 NBL 值以与特定胎龄正常中位数（MoM）的倍数表示，并以 PT/NBL 比值表示。还使用逻辑回归合并关于 PT 和 NBL MoM 的信息。结果根据是否大于 PT、PT/NBL 和来自逻辑回归方程的 DS 风险的正常第 95 百分位数或 NBL 的第 5 百分位数进行分类。
DS 病例和正常对照组的中位数分别为：PT 1.26 和 0.996 MoM；NBL 0.596 和 0.993 MoM。PT 阳性结果的 DS 胎儿比例为 41%，NBL 为 65%，PT/NBL 比值和逻辑回归方程的 DS 风险均为 82%。PT/NBL 水平与胎龄无关。
PT/NBL 比值是一种有价值的早孕期 DS 筛查标志物，可与 NT 测量同时进行。
