Bromley B, Nadel A S, Pauker S, Estroff J A, Benacerraf B R
Department of Obstetrics and Gynecology, Massachusetts General Hospital, Boston.
Radiology. 1994 Dec;193(3):761-3. doi: 10.1148/radiology.193.3.7972820.
To evaluate with sonography the normal development of the fetal cerebellum in the second trimester.
The study included all patients undergoing second trimester genetic amniocentesis who had structurally normal fetuses, in whom the posterior fossa was adequately seen and in whom the karyotype was later determined to be normal. Views of the cerebellum were obtained prospectively, and the inferior vermis was determined to be open or closed at the time of the initial scan. Follow-up was obtained by means of subsequent scans and review of the pediatric record.
Of 897 fetuses that met the inclusion criteria, 147 had an open vermis at initial scanning. At 14 weeks gestation, 56% of fetuses had an open vermis, decreasing to 23% at 15 weeks and 6% at 17 weeks. In utero follow-up sonograms were obtained in 79% of fetuses with an initially open vermis and demonstrated closure in all but one fetus. The remaining 21%, without sonographic follow-up, were normal as newborns.
The prenatal diagnosis of Dandy-Walker variant should not be made before 18 weeks gestation because the development of the cerebellar vermis may be incomplete at that time.
通过超声评估孕中期胎儿小脑的正常发育情况。
该研究纳入了所有接受孕中期遗传羊膜穿刺术且胎儿结构正常、后颅窝能清晰显示且染色体核型后来确定为正常的患者。前瞻性地获取小脑图像，并在初次扫描时确定小脑蚓部下蚓部是开放还是闭合。通过后续扫描和查阅儿科记录进行随访。
在897例符合纳入标准的胎儿中，147例在初次扫描时蚓部开放。妊娠14周时，56%的胎儿蚓部开放，15周时降至23%，17周时降至6%。79%最初蚓部开放的胎儿进行了宫内随访超声检查，除1例胎儿外其余均显示蚓部闭合。其余21%未进行超声随访的胎儿出生后正常。
孕18周前不应进行Dandy-Walker变异型的产前诊断，因为此时小脑蚓部的发育可能不完全。
