Patient Data
Vermis hypoplasia with an enlarged fourth ventricle communicating with the cisterna magna. There is rotation of the hypoplastic cerebellar vermis and upward displacement of the torcular herophili. Associated agenesis of the corpus callosum with colpocephaly (appearance of disproportionate enlargement of the occipital horns).
Image 1: Green arrow = vermian hypoplasia. Thick red line = superior border of the fourth ventricle. Yellow line = upward sloping tentorium cerebelli. Thin red line - outline of brainstem.
Image 2: Red line indicates abnormal ventricular system with the "moose head" configuration on the coronal image.
Case Discussion
Dandy-Walker complex type A.