三维超声第三平面成像监测胎儿小脑蚓部发育的研究

目的评价三维超声第三平面成像方法对小脑蚓部发育的监测价值，同时获取胎儿各孕周小脑蚓部发育的正常参考值。方法2004年10月至2005年5月中山大学附属第一医院采用经腹、经阴道二维和经腹三维超声等方法观察200例中晚孕期胎儿小脑结构，记录并比较3种方法显示小脑正中矢状切面，即小脑蚓部最大切面的成功率。测量小脑蚓部前后径、上下径和切面面积，并分析其与孕周的关系。结果经腹二维、经阴道二维和经腹三维超声第三平面成像显示小脑蚓部成功率分别为35．5％、26．0％及98．5％，差异有极显著性意义（P〈0．01）。应用三维超声第三平面成像测量小脑蚓部前后径、上下径和最大切面面积均与孕周呈正相关。结论三维超声第三平面成像能够克服二维扫查难以获取胎儿头颅正中矢状切面的不足，得到满意的小脑正中矢状切面图像。小脑蚓部随孕周发育的变化规律及其正常测量数据为进一步判断病变提供了参照标准。

Study on the development of fetal cerebellar vermis with the third plane image of three-dimensional ultrasonography

Objective To evaluate the third plane image of three-dimensional sonography (3D US) for determining the normal appearance of the fetal cerebellar vermis and to establish a normal growth chart. Methods The cerebellum was scanned with trans-abdominal two-dimensional ultrasound (TAS), trans-vaginal two-dimensional ultrasound (TVS) and trans-abdominal 3D US in the second and third trimester in 200 fetuses in the First Affiliated Hospital of Sun Yat-sen University from Oct. 2004 to May 2005. The detection rate of the mid-sagittal plane of the cerebellar vermis in different ways was compared. The mid-sagittal antero-posterior and cranio-caudal vermian diameters and surface area of the vermis were measured and calculated. The correlation between the vermian growth and the pregnant week was described. Results The success rate in showing the mid-sagittal plane of the vermis with TAS, TVS and the third plane of 3D US were 35.5%, 26.0% and 98.5%, respectively. There was significant difference between 3D US and TAS or TVS (P< 0.01). The vermis grew in a linear fashion throughout pregnancy and the growth pattern correlated well with gestational age. Conclusion The third plane image obtained by 3D US is a valuable way in studying the fetal cerebellar vermis during the middle and late pregnancy. Knowledge of normal vermian appearance may help identify developmental anomalies and enable accurate prenatal counseling.