Bahado-Singh R O, Wyse L, Dorr M A, Copel J A, O'Connor T, Hobbins J C
Department of Obstetrics and Gynecology, Yale University School of Medicine, New Haven, CT 06510.
Am J Obstet Gynecol. 1992 Oct;167(4 Pt 1):1009-14. doi: 10.1016/s0002-9378(12)80029-9.
The purpose of our study was to determine whether the frontal lobe is significantly smaller than normal in the Down syndrome fetus in midtrimester.
Frontothalamic distance, measured from the inner table of the frontal bone to the posterior thalamus, and frontothalamic distance/biparietal diameter ratio were compared in 125 normal and 19 Down syndrome fetuses between 16 and 21 weeks' gestation.
In the Down syndrome group 52% had frontothalamic distance < 10th percentile. When the frontothalamic distance and the frontothalamic distance/biparietal diameter ratio were expressed as multiples of the normal median to eliminate variation caused by gestational age, the mean value of multiples of the median in Down syndrome fetuses was compared with the mean value of multiples of the median in normal fetuses and was found to be significantly smaller (p < 0.0019 and p < 0.0177, respectively). When an observed-to-expected frontothalamic distance ratio of < or = 0.84 is used as a cutoff to screen for Down syndrome, sensitivity, specificity, and positive predictive values of 21.2%, 95.2%, and 1.2%, respectively, are achieved in a population with a 1:270 risk.
Frontal lobe dimension is significantly shortened in Down syndrome fetuses.
我们研究的目的是确定孕中期唐氏综合征胎儿的额叶是否明显小于正常胎儿。
测量了125例正常胎儿和19例唐氏综合征胎儿在孕16至21周时从额骨内板到丘脑后部的额丘脑距离以及额丘脑距离/双顶径比值。
在唐氏综合征组中，52%的胎儿额丘脑距离小于第10百分位数。当将额丘脑距离和额丘脑距离/双顶径比值表示为正常中位数的倍数以消除孕周引起的差异时，将唐氏综合征胎儿中位数倍数的平均值与正常胎儿中位数倍数的平均值进行比较，发现前者明显更小（分别为p < 0.0019和p < 0.0177）。当将观察到的与预期的额丘脑距离比值≤0.84作为筛查唐氏综合征的临界值时，在风险为1:270的人群中，敏感性、特异性和阳性预测值分别为21.2%、95.2%和1.2%。
唐氏综合征胎儿的额叶尺寸明显缩短。
