超声诊断和鉴别诊断胎儿颅后窝池畸形

Ultrasound in diagnosis and differential diagnosis of fetal posterior fossa malformations

胎儿颅后窝池畸形主要包括Dandy-Walker综合征、Blake囊肿和颅后窝蛛网膜囊肿,其中Dandy-Walker综合征又包括典型的Dandy-Walker畸形、小脑蚓部发育不良(Dandy-Walker变异型)及巨大枕大池。各种颅后窝池畸形的预后差异较大,约90%Blake囊肿和巨大枕大池胎儿神经系统发育正常,而Dandy-Walker畸形和小脑蚓部发育不良胎儿中,约50%伴神经系统发育异常。各类型颅后窝畸形超声表现相似,鉴别诊断困难,应用二维超声与三维超声相结合,可获得理想的胎儿头部正中矢状切面,对鉴别诊断胎儿颅后窝池畸形帮助极大。

Posterior fossa malformation consists of Dandy-Walker syndrome, including classic Dandy-Walker malformation, vermian hypoplasia （Dandy-Walker variant） and megacisterna magna, Blake＇s pouch cyst, as well as posterior fossa arachnoid cysts. There are great differences in the prognosis of various types of malformations. About 90% of fetuses of Blake＇s pouch cyst or megacisterna magna are not associated with nervous system abnormalities, and 50% of fetuses of Dandy-Walker malformation and vermian hypoplasia have normal neurologic development. The ultrasonic manifestations of different types of posterior fossa malformations are similar, leading to difficult differential diagnosis. Combining two-dimensional with three-dimensional multiplanar ultrasound can get optimal fetal median sagittal section, which is helpful to the differential diagnosis of these malformations.