Posterior brain in fetuses with Dandy–Walker malformation with complete agenesis of the cerebellar vermis at 11–13 weeks: a pilot study

ABSTRACT Objective

This study aimed to measure the changes in the posterior brain in fetuses with Dandy–Walker malformation (DWM) with complete agenesis of the cerebellar vermis between 11⁺⁰ and 13⁺⁶ weeks of gestation.

In the midsagittal view, the brain stem (BS) diameter and the brain stem to occipital bone (BSOB) diameter were measured, and the BS/BSOB ratio was calculated in four fetuses with confirmed DWM and 40 normal fetuses. Delta values corrected for CRL were compared between both groups.

In contrast to the normal controls, in fetuses with DWM at 11⁺⁰ to 13⁺⁶ weeks of gestation, the border between the fourth ventricle and the cisterna magna was not visible. There were no significant differences in the BS diameter between the two groups (p < 0.3). In the DWM group, the mean diameter of the BSOB was found to be significantly higher than in the controls (p = 0.0011), and it was above the 95th centile in all four cases. In addition, the BS/BSOB ratio was significantly decreased in fetuses with DWM (p = 0.0011).

At 11–13 weeks, fetuses with DWM have measurable abnormalities in the posterior brain. An abnormal appearance of the fourth ventricle–cisterna magna complex was present in all four cases of DWM. © 2012 John Wiley & Sons, Ltd.