Three-Dimensional sonography of the posterior fossa in fetuses with Dandy Walker malformation at 11–13 weeks

Ziel: The aim of the study is to assess potential clinical applicability of the 3D-sonography in early prenatal detection of Dandy Walker Malformation (DWM).

Methodik: Twenty five 3D volume data sets obtained between 11+0 and 13+6 weeks of gestation in 20 fetuses with normal brain anatomy and 5 fetuses with DWM used for the study. 3D volumes of the fetal head were acquired at the mid-sagittal view. Standardization of each volume was performed in the three orthogonal planes. The brain stem diameter, brain stem to occipital bone diameter, 4th ventricle and cisterna magna were assessed. All measurements were expressed as Z-score values. The diagnostic value and image quality was evaluated.

Ergebnis: In contrast to the normal controls, in fetuses with Dandy Walker Malformation at 11+0–13+6 weeks' gestation the border between 4th ventricle and cisterna magna was absent. In addition, cerebellar hypoplasia and enlargement of posterior fossa were noted in all three orthogonal planes. There was no significant differences in the brain stem diameter between 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 < 0.01) and it was above the 95th centile in all 5 cases (average Z-score=3,7). In addition BS diameter to BSOB diameter ratio was significantly decreased in fetuses with DWM (average Z-score=–4,3).

Schlussfolgerung: To our knowledge this is the first study to evaluate potential clinical applicability of 3-D sonography for early detection of DWM. This technique demonstrates a good display of the diagnostic landmarks of DWM with appropriate quality of images. By standardizing the approach to image acquisition and display 3D-sonography may potentially improve the detection of DWM in early pregnancy.