Sepulveda Waldo, Wong Amy E, Andreeva Elena, Odegova Natalia, Martinez-Ten Pilar, Meagher Simon
Fetal Medicine Center, Fetal Medicine Interest Group GIMEF, Santiago, Chile (W.S., A.E.W.); Medical-Genetics Department, Moscow Regions Research Institute of Obstetrics and Gynecology, Moscow, Russia (E.A., N.O.); Delta-Ultrasound Diagnostic Center for Obstetrics and Gynecology, Madrid, Spain (P.M.-T.); and Monash Ultrasound for Women, Melbourne, Victoria, Australia (S.M.).
J Ultrasound Med. 2014 Jul;33(7):1165-9. doi: 10.7863/ultra.33.7.1165.
To determine whether the biparietal diameter measurement is altered in first-trimester fetuses with holoprosencephaly.
Cases of holoprosencephaly were collected retrospectively from 4 fetal medicine centers, and first-trimester biparietal diameter measurements were reviewed. The diagnosis of holoprosencephaly was established sonographically by the detection of abnormal choroid plexus morphologic characteristics (absent "butterfly" sign) and the identification of a monoventricular cerebral cavity on axial views of the fetal brain. The proportion of fetuses with biparietal diameter measurements below the 5th percentile for crown-rump length was determined.
Among 45 cases of holoprosencephaly reviewed, 43 had information on both biparietal diameter and crown-rump length measurements. The biparietal diameter was below the 5th percentile for crown-rump length in 14 (32.6%) fetuses. Chromosomal analysis was available in 41; no statistically significant difference in biparietal diameter measurement between those with associated chromosomal anomalies and those without anomalies was noted. A supplementary analysis using head circumference measurement showed an even greater proportion of fetuses with holoprosencephaly with measurements below the 5th percentile for crown-rump length (18 of 42 [42.9%]).
One-third of first-trimester fetuses with a sonographic diagnosis of holoprosencephaly had a biparietal diameter that was smaller than expected for crown-rump length. In this subset of fetuses, the evaluation of intracranial anatomy for signs of holoprosencephaly may be more difficult to perform due to the smaller size of the brain. Therefore, the detection of a biparietal diameter below the 5th percentile as expected from crown-rump length on the first-trimester scan may be a warning sign of holoprosencephaly and should prompt a detailed examination of the intracranial anatomy.
确定全前脑畸形的孕早期胎儿双顶径测量值是否有改变。
从4个胎儿医学中心回顾性收集全前脑畸形病例，并复查孕早期双顶径测量值。通过超声检测异常脉络丛形态特征（无“蝴蝶”征）以及在胎儿脑轴位视图上识别单脑室脑腔来确立全前脑畸形的诊断。确定双顶径测量值低于头臀长第5百分位数的胎儿比例。
在复查的45例全前脑畸形病例中，43例有双顶径和头臀长测量的相关信息。14例（32.6%）胎儿的双顶径低于头臀长的第5百分位数。41例可进行染色体分析；伴有染色体异常和不伴有异常的胎儿在双顶径测量值上未发现统计学显著差异。使用头围测量的补充分析显示，全前脑畸形胎儿中测量值低于头臀长第5百分位数的比例更高（42例中的18例[42.9%]）。
超声诊断为全前脑畸形的孕早期胎儿中有三分之一的双顶径小于根据头臀长预期的值。在这部分胎儿中，由于脑体积较小，评估颅内解剖结构以寻找全前脑畸形的迹象可能更困难。因此，孕早期超声扫描时双顶径低于根据头臀长预期的第5百分位数可能是全前脑畸形的一个警示信号，应促使对颅内解剖结构进行详细检查。
