[MRI of cerebral cortical dysgenesis]

Cortical cerebral dysgenesis is a heterogeneous disorder of cortical development and organization. It is well known by neuropathologists and is becoming more important in the clinical setting, mainly due to MRI. Our purpose is to report the MRI features of cortical dysplasia in 30 patients and to propose a simple classification with review of the literature.

It is a retrospective study of the MRI features of 30 cases of cortical dysgenesis. All patients were evaluated by electroencephalography and brain MRI using T1 and T2 weighted, inversion recovery T1 weighted, FLAIR and MPR 3D sequences with multiplanar reformations.

Twenty-nine patients were referred to the neurology department because of refractory epilepsy and one patient for mental retardation. Our patients were distributed in 4 groups: diffuse forms represented by agyria-pachygyria (4 cases), polymicrogyria (one case), and nodular heterotopias (5 cases), local bilateral forms represented by bilateral polymicrogyria (11 cases), unilateral forms represented by hemi-megalencephaly (one case), and focal cortical forms found in eight cases.

Neuroblast migration disorders are better known, mainly due to high resolution MRI techniques that by the quality of multiplanar study and a better differentiation between gray and white matter, allow a more precise diagnosis.