Wüest Anja, Surbek Daniel, Wiest Roland, Weisstanner Christian, Bonel Harald, Steinlin Maja, Raio Luigi, Tutschek Boris
Department of Obstetrics and Gynecology, Inselspital, University of Bern, Bern, Switzerland.
Institute of Diagnostic and Interventional Neuroradiology, Inselspital, University of Bern, Bern, Switzerland.
Acta Obstet Gynecol Scand. 2017 Jul;96(7):837-843. doi: 10.1111/aogs.13131. Epub 2017 Apr 10.
The primary aim of this study was to ascertain the prevalence of the individual conditions and of associated anomalies in fetuses with the prenatal diagnosis of enlarged posterior fossa (PF) and to explore the diagnostic accuracy of ultrasound in these anomalies. The secondary aim was to evaluate the postnatal outcome of children affected by PF anomalies.
All fetuses with enlarged PF detected by prenatal sonography at a referral center from 2001 to 2015 were analyzed retrospectively. Some were also studied by fetal magnetic resonance imaging (MRI) or volume ultrasound examinations. Fetal sonographic and MRI were compared using following classification: Dandy-Walker malformation (DWM); megacisterna magna (MCM); Blake's pouch cyst; isolated vermian hypoplasia; vermian agenesis; PF arachnoid cyst (AC); and cerebellar hypoplasia (CH).
The ultrasound diagnoses of the 69 fetuses were as follows: MCM (n = 29; of these isolated n = 15), DWM (n = 28, isolated n = 4), vermian hypoplasia (n = 5, isolated n = 4), Blake's pouch cyst (n = 4, isolated n = 1), CH (n = 2; none isolated) and AC in the PF (n = 1, isolated). Thirteen of the 41 karyotyped fetuses were aneuploid, including seven with DWM. Associated malformations were found in 37/69 cases. There were 39 live births, including 11 with confirmed DWM, six of whom show a normal development. Twelve infants with isolated MCM show normal development. There were eight false-positive prenatal diagnoses (or resolution until birth) of "enlarged PF": three with Blake's pouch cyst, two with MCM and one with vermian hypoplasia.
An enlarged PF requires specific diagnoses for the best possible counseling. The term "Dandy-Walker variant" should not be used anymore. Isolated MCM and Blake's pouch cyst can either resolve or be normal variants, but may also indicate the presence of a more severe anomaly or associated malformations.
本研究的主要目的是确定产前诊断为后颅窝（PF）增大的胎儿中各种个体情况及相关异常的患病率，并探讨超声对这些异常的诊断准确性。次要目的是评估受PF异常影响儿童的出生后结局。
对2001年至2015年在一家转诊中心通过产前超声检查发现PF增大的所有胎儿进行回顾性分析。部分胎儿还接受了胎儿磁共振成像（MRI）或容积超声检查。胎儿超声检查和MRI检查结果按照以下分类进行比较：Dandy-Walker畸形（DWM）；巨大枕大池（MCM）；Blake囊肿；孤立性小脑蚓部发育不全；小脑蚓部缺如；PF蛛网膜囊肿（AC）；以及小脑发育不全（CH）。
69例胎儿的超声诊断结果如下：MCM（n = 29；其中孤立性MCM为n = 15），DWM（n = 28，孤立性DWM为n = 4），小脑蚓部发育不全（n = 5，孤立性小脑蚓部发育不全为n = 4），Blake囊肿（n = 4，孤立性Blake囊肿为n = 1），CH（n = 2；均非孤立性）以及PF内AC（n = 1；孤立性）。41例进行了核型分析的胎儿中有13例为非整倍体，其中7例患有DWM。69例中有37例发现相关畸形。共有39例活产，其中11例确诊为DWM，其中6例发育正常。12例孤立性MCM婴儿发育正常。有8例产前诊断为“PF增大”的假阳性结果（或直至出生时病变消失）：3例为Blake囊肿，2例为MCM，1例为小脑蚓部发育不全。
PF增大需要进行特定诊断以便提供最佳咨询。不应再使用“Dandy-Walker变异型”这一术语。孤立性MCM和Blake囊肿可能会自行消失或为正常变异，但也可能提示存在更严重的异常或相关畸形。
