The CT and MR evaluation of migrational disorders of the brain. Part II. Schizencephaly, heterotopia and polymicrogyria.

The migrational disorders are a rare group of congenital malformations of the brain. They consist of the following entities - lissencephaly (agyria - pachygyria), pachygyria, schizencephaly, heterotopia and polymicrogyria. We studied 40 children with migrational disorders radiologically with CT and MR. This article (Part II) deals with our patients with schizencephaly, heterotopia and polymicrogyria. These patients presented clinically with a variety of symptoms. The most common were seizures, delayed development, failure to thrive and hydrocephalus. CT and MR both demonstrated the characteristic findings in all of our patients except the polymicrogyria group. The gray matter and cleft abnormalities seen in these disorders were demonstrated with CT and MR. However, MR provided better delineation of these disorders than CT. Because some forms of migrational disorders can be inherited, it is extremely important for the radiologist to understand the characteristic findings for correct diagnosis which is essential for parental counseling.