[Diagnosis of infratentorial malformations in infancy (author's transl)].

In a newborn boy with hydrocephalus the computed tomography (CT) demonstrates hypoplastic hemispheres of the cerebellum, the inferior part of the vermis is lacking and the enlarged cisterna magna is directly communicating with the fourth ventricle. The ventricles 1--3 are markedly enlarged. Only the additional studies after the application of Metrizamide intrathecally could demonstrate the direct communication of the spinal CSF system with the fourth ventricle, determining the diagnosis: Dandy-Walker-Variant. The computed tomography-cisternography (CTC) is an important additional investigation with only minimal risks to the patient.