Prenatal MR imaging of Dandy-Walker complex: midline sagittal area analysis.

OBJECTIVE

To measure the mid-sagittal areas of vermis (VA) and of posterior fossa (PFA) and determine their differences among fetuses with various Dandy-Walker (DW) entities and control subjects.

METHODS

We reviewed data in 25 fetal patients with a MR diagnosis of DW complex including hypoplastic vermis (HV), HV with rotation (HVR), and mega cistern magna (MCM), and in 85 fetal controls with normal CNS. PFA and VA of each subject were manually traced on mid-sagittal MR images. Regarding each of VA and PFA, after age correction, we determined statistically significant differences among HVR, HV, MCM, and control groups.

RESULTS

The mean VA residue of MCM was greater than that of the control, which was in turn greater than those of HVR and HV. The mean PF residue of the control was smaller than all other groups.

CONCLUSION

Fetuses with HVR or HV had smaller VA than fetuses with MCM or control subjects. Fetuses with MCM, HVR, or HV had larger PFA than control subjects. These results may be an early step leading to better understanding of the confusion about the PF anomalies in future.