[Cortical malformations and epilepsy: Role of MR imaging]

Malformations of cortical development are increasingly recognized as important causes of epilepsy, developmental delay and other neurological disorders. Our purpose is to present the relevance of the MRI in these pathologies with the clinical, genetic and therapeutic aspects. This classification is based on the three fundamental events of cortical formation: proliferation of neurons and glie in the periventricular zone, migration of postmitotic neurons to the periphery, subsequent cortical organization. MR analysis evaluates particularly the cortical thickness, sulcal and cortical morphology, gray-white matter junction, and looks for gray matter in abnormal location. These data coupled with the familial history, the seizure characteristics and genetic findings should allow an appropriate classification of the lesions. MR imaging allows the detection and classification of cortical malformations. MR imaging findings are primordial to consider surgery when the epilepsy becomes refractory to the anti-epileptic drugs. An adequate classification of these malformations should help to provide to the family an appropriate counseling both in terms of genetics and outcome.