What ultrasound finding is typical for Dandy-Walker Malformation?

Dandy-Walker Malformation is characterized by an abnormal development of the cerebellum, particularly involving the fourth ventricle and the posterior fossa. One of the hallmark ultrasound findings is the enlargement of the posterior fossa, which can be visualized as a cystic dilation of the fourth ventricle and a considerable increase in the size of the space between the cerebellar hemispheres.

This enlargement reflects the underlying developmental anomalies, including agenesis or dysgenesis of the cerebellar vermis and cystic enlargement of the fourth ventricle. Consequently, when such a posterior fossa enlargement is detected during imaging, it strongly indicates the presence of Dandy-Walker Malformation and is a critical sign for diagnosis.

Other choices may present neurological defects or conditions affecting the brain, but they do not specifically represent the unique ultrasound characteristics of Dandy-Walker Malformation.