RIU 435 Lecture Notes - Lecture 8: Dandy–Walker Syndrome, Aqueductal Stenosis, Fourth Ventricle

• School: GVSU
• Department: Radiation and Imaging - Ultrasound
• Course: RIU 435
• Professor: Taytana Beaves

Document Summary

Defect that may have varying degrees of severity. Agenesis or hypoplasia of cerebellar vermis with resulting dilation on fourth ventricle and enlargement of posterior fossa. Dandy walker complex encompasses the three main types of posterior fossa malformations. Dw variant manifests with cystic dilatation of the fourth ventricle and hypoplasia of the cerebellum vermis without an enlargement posterior fossa. Megacisterna magna- defined as an enlargement cistern magna. Communications between 4th ventricle and cistern magna not complete until week 18 of gestation. Diagnosis of agenesis and hypoplasia of cerebellar vermis should not be made prior to week 18. Associated with other intracranial anomalies about 50% of time, including: Chromosomal anomalies that may be associated include trisomies. Associated with several syndromes: meckel- gruber, walker- Is linked to congenital infections and maternal diabetes. Prognosis depends on presence or absence of associated anomalies and on degree of hypoplasia of cerebellar vermis, as correlates with severity of mental retardation.