[Advances in the physiopathology of epileptogenesis: metabolic aspects in vivo].

: This communication shows how proton magnetic resonance spectroscopy (MRS) is currently being employed in the study or the diagnosis of epilepsy. With this goal, the kind of biochemical information of cerebral parenchyma available with this non invasive technique is first introduced in a succinct way. The value of this metabolic information is then illustrated through several cases of temporal and extratemporal epilepsy, for which magnetic resonance imaging was either non diagnostic or uncertain. In this context, the asymmetry index, very useful for the lateralization of epileptogenic foci on the basis of quantitative spectroscopic criteria, is defined. Finally, other potentials of MRS, beyond its ability to elucidate the existence of neuronal damage in the epileptogenic zone, are considered. Hence, cases with postictally increased lactate, or increased glutamine/glutamate without apparent neuronal damage, are presented as good examples of the diagnostic or lateralizing value of MRS.