HETEROTOPIC GREY-MATTER - MR AND CLINICAL FINDINGS

Heterotopias are conglomerates of neurons and glial cells in an abnorm al location and belong to a group of malformations, which are the resu lt of a disturbed migration of neurons during the embryonic developmen t of the brain. The MRI-appearance and clinical symptoms of 14 patient s with nodular or lamellar heterotopias are presented. Seizures were t he leading symptom (12 of 14 patients), in children also a development al deficit (4/10) with or without seizures. Most of the children (9/10 ) had further brain malformations especially of the corpus callosum or the cerebellar vermis. Nodular heterotopias without further malformat ions were found in 4 patients, two of them developing grand-mal seizur es after childhood. On MRI heterotopias are characterized by a signal isointense to gray matter in all sequences. MRI-scans in at least 2 or ientations are necessary to detect these anomalies reliably. MRI is th e optimum method for the demonstration of these anomalies and should a lways be performed if seizures develop during childhood. At least in n odular heterotopias there is no definite correlation between the exten t of the anomalies, the EEG-findings and the clinical symptoms. Howeve r there is a frequent combination of heterotopias with further cerebra l malformations.