经腹二维超声评估胎儿小脑蚓部发育

Application of transabdominal two-dimensional ultrasonography in detection of cerebellar vermis in fetus

目的建立不同孕周正常胎儿小脑半球和蚓部数据参考值范围，分析其与孕周的相关性，并评估其在小脑蚓部发育中的应用价值。方法采用二维超声测量390例18～40孕周正常单胎胎儿小脑半球宽度（CW）、小脑半球高度（CH）、蚓部宽度（VW）、蚓部高度（VH），并计算小脑蚓部与半球的宽度比值（VW／CW）及高度比值（VH／CH）。各测量指标与孕周的关系采用Pearson相关分析，并按照上述测量方法对18例单纯性枕大池增宽（CM）及6例蚓部发育不良胎儿进行评估。结果正常胎儿CW、CH、VW、VH均随孕周增大而增大，R^2分别为0．952、0．712、0．905和0．894；VW／CW随孕周增大而减小，R^2=0．659；VH／CH与孕周不存在明显相关关系，R^2=0．007。正常胎儿VH／CH平均为0．76±0．04，CM胎儿VH／CH平均为0．74±0．03，两者比较差异无统计学意义（Z=-1．35，P=0．18）；蚓部发育不良胎儿VH／CH平均为0．58±0．04，明显低于正常胎儿（Z=-4．22，P=0．001）。结论二维超声评估胎儿小脑蚓部发育是一种简便、快速、有效的方法，VH／CH可作为产前定量评估胎儿小脑部发育不良的一个重要参考指标。

Objective To establish the normal data of the fetal cerebellar hemispheres and vermis, analyse its relationship with different gestational age, and evaluate its clinical significance in the diagnosis of the eerebellar vermis abnormalities. Methods Totally 390 normal singleton fetuses between 18 and 40 gestational weeks （GW） were enrolled in this study, two-dimensional uhrasound（2DUS） technology was used to measure cerebellar width （CW）, cerebellar height （CH）, vermian width （VW） and vermian height （VH）, then the correlation between all measurements and the gestational weeks was analyzed. Eighteen fetuses with mega cisterna magna and 6 fetuses with vermis hypoplasia were assessed and compared with the normal fetuses. Results In all healthy controls, CW, CH, VW, and VH increased with GW （R^2 = 0.952,0.712,0.905,0.894,respectively）. VW/CW decreased with GW increasing （R^2 = 0.659）. VH/CH had no relationship with GW （R^2 = 0. 007）. VH/CH in normal fetuses was 0.76± 0.04, VH/CH in fetuses with CM was 0.74 ± 0.03, there was no significant difference between them（ Z = - 1.35, P = 0.18） ;VH/ CH in fetuses with hypoplasia was 0.58 ± 0.04, and was smaller than that of healthy controls （Z = - 4.22, P = 0. 001）. Conclusions Evaluating fetal cerebellar vermis development by two-dimensional ultrasound is a kind of simple, fast and effective method. VH/CH is an important reference indicators and can be used for prenatal diagnosis of cerebellar vermis abnormalities.