Service Hospitalier Frédéric-Joliot, CEA, 4, place du Général-Leclerc, 91400 Orsay.
The important development of non invasive techniques of cerebral imaging dramatically improved the presurgical work-up and the study of mental sequelae in childhood epilepsy. MRI's spatial resolution improved, so it is possible to detect subtle epileptogenic lesions, even in very young patients. By visualizing more and more accurately the sulcogyral macroanatomy, MRI permits a genetic and syndromic approach of cerebral lesions associated with epilepsy. Ictal SPECT helps localizing the epileptogenic zone and placing intracranial EEG electrodes, using strict methodology with simultaneous video-EEG and multidisciplinary interpretation of the images. Functional MRI can localize motor cortex and language networks, as well as it can lateralize language with a good correlation with WADA test, using selected activation tasks in cooperative children. Interictal SPECT and PET show the dysfunctioning areas involved in the neuropsychological and behavioural disorders associated with epilepsy. Finally, fMRI may study post-lesional and post-surgical plasticity by comparing longitudinal studies in a given patient.