Imaging of malformations of the hindbrain and craniocervical junction

Abstract

Primary hindbrain malformations are much less frequent than those of the cerebrum or combined anomalies. Cerebellar malformations may affect both hemispheres such as rhombencephalosynapsis or molar tooth malformations. Dysplastic gangliocytoma in Lhermitte-Duclos-Cowden syndrome is a typical unilateral malformation. Unilateral hypoplasia usually represents cerebellar disruption, i.e. an impact during intrauterine development. The Dandy-Walker complex (DWC) as well as the Chiari malformations are often accompanied by hydrocephalus, either infra- or supratentorial. DWC is a malformation of the fourth ventricle and its CSF outfl ow with hydrocephalus as the major complication. In Chiari I malformation CSF hydrodynamics are disturbed and frequently lead to syringomyelia, whereas Chiari malformations II and III are associated with spinal dysraphism which signifi - cantly affects the prognosis.