Harris Birthright Research Centre for Fetal Medicine, King's College Hospital, London, UK.
Prenat Diagn. 2012 Sep;32(9):854-8. doi: 10.1002/pd.3920. Epub 2012 Jun 13.
To measure changes in the posterior fossa of first-trimester fetuses with trisomy 18, trisomy 13 and triploidy.
Brain stem (BS) diameter and BS to occipital bone (BSOB) diameter were measured in images of the midsagittal view of the face at 11(+0) to 13(+6) weeks from 45 trisomy 18, 21 trisomy 13 and 15 triploid fetuses and compared with values in 162 euploid fetuses.
In euploid fetuses BS and BSOB diameters increased significantly with crown-rum length and the BS to BSOB ratio decreased. In all three aneuploidies BSOB diameter was significantly higher than in euploid fetuses. In trisomy 18 and trisomy 13, the BS diameter and BS to BSOB ratio were decreased. The BS to BSOB ratio was below the 5(th) percentile in 16 (35.6%), 17 (81.0%) and 5 (33.3%) of trisomy 18, trisomy 13 and triploidy, respectively. In 7 (8.6%) of the aneuploid fetuses there was open spina bifida and in all these cases the BS to BSOB ratio was above the 95(th) percentile.
At 11 to 13 weeks' gestation many fetuses with trisomy 18, trisomy 13 and triploidy have measurable abnormalities in the posterior brain.
测量三体 18、三体 13 和三倍体胎儿 11 至 13 孕周时后颅窝的变化。
在 45 例三体 18、21 三体 13 和 15 三倍体胎儿和 162 例整倍体胎儿的面部正中矢状位图像中测量脑桥（BS）直径和 BS 到枕骨（BSOB）直径，并与正常值进行比较。
在整倍体胎儿中，BS 和 BSOB 直径随头臀长显著增加，BS 与 BSOB 的比值降低。在所有三种非整倍体中，BSOB 直径均显著高于整倍体胎儿。在三体 18 和三体 13 中，BS 直径和 BS 与 BSOB 的比值降低。BS 与 BSOB 的比值分别在 16 例（35.6%）、17 例（81.0%）和 5 例（33.3%）三体 18、三体 13 和三倍体中低于第 5 百分位数。在 7 例（8.6%）非整倍体胎儿中存在开放性脊柱裂，在所有这些病例中，BS 与 BSOB 的比值均高于第 95 百分位数。
在 11 至 13 孕周时，许多三体 18、三体 13 和三倍体胎儿的后颅窝存在可测量的异常。
