胎儿小脑延髓池间隔的超声检测及其临床意义

摘要

Objective To establish normative data for the fetal cisterna magna septa (CMS) at various gestational age,and to evaluate its clinical significance.Methods A total of consecutive fetal between 14 and 40 gestational week(GW) were included in this prospective study.The length and width of CMS were measured by two-dimensional ultrasonography.Regression analysis was used to study the relationship between the width and length of the fetal cisterna magna septa and gestational age.Twenty-five case of fetuses with the absence of CMS and 12 case of fetuses with the enlargement of CMS were retrospectively analyzed in the past six years in our hospital.Results ①The fetal CMS length and width increased gradually between 14 and 22 GW,then plateaued between 23 GW and 36 GW,and decreased after 37 GW.This ultrasonographic pattern was in agreement with normal development of rhombencephalon.②The absence of CMS in the fetuses were common in Dandy-Walker syndrome,holoprosencephaly,severe hydrocephalus,neural tube defects,rhombencephalon synapsis and Arnold-Chiari malformation.The enlargement of CMS in the fetuses may be shown in physiologic enlargement of posterior fossa.ConclusionsCMS is a potential new marker for normal development of rhombencephalon.The enlargement and absence of CMS are related to various malformations of central neural system,especially in the abnormalities of posterior fossa.%目的 探讨不同孕龄胎儿小脑延髓池间隔(CMS)的正常声像图表现及正常值,并评估CMS的临床意义.方法 前瞻性选择416例不同孕周正常胎儿,采用二维超声对CMS的长径和宽径进行检测,并对其测值与孕周进行回归分析.回顾性总结我院6年间25例CMS消失的病例和12例CMS增大胎儿的临床资料.结果 ①胎儿CMS的长径和宽径在14～22孕周随着孕周的增加而增大,在23～36孕周变化不大,在37孕周后有变小趋势,与菱脑胚胎发育过程一致.②CMS消失常见于Dandy-Walker畸形、全前脑、严重脑积水、神经管缺陷、菱脑融合症、Arnold-Chiari畸形;CMS增大可见于小脑延髓池生理性增大.结论 CMS是菱脑发育正常的标志之一.CMS增大和消失与多种胎儿中枢神经系统畸形有关,尤其是后颅窝畸形.