MRI reveals structural abnormalities in patients with idiopathic generalized epilepsy.

OBJECTIVE: To evaluate MRI findings in a large group of patients with idiopathic generalized epilepsies.

METHODS: Idiopathic generalized epilepsies were diagnosed according to clinical and EEG criteria following International League Against Epilepsy recommendations. MRI was performed in a 2.0 T scanner using a previously established epilepsy protocol. Images were reviewed, and any abnormality was reported. Patients were divided in those with and without MRI abnormalities. Comparisons were made between these groups concerning age, age at seizure onset, subsyndrome, EEG findings, and seizure control.

RESULTS: Of the 134 MRIs evaluated, 33 (24%) showed abnormalities, most of which (88%) were nonspecific. There were eight main abnormalities: arachnoid cyst, diffuse cortical atrophy, basal ganglia abnormalities (signal alterations and prominent perivascular spaces), ventricular abnormalities (uni- or bilateral increased volume of the lateral ventricles), white matter abnormalities (increased T2 signal in the frontal lobes), reduced hippocampal volume, focal gyral abnormality, and area of gliosis in the frontal lobe. Comparisons between the groups showed a higher proportion of EEG focalities in patients with abnormal MRI, which were in most part concordant with the location of the MRI abnormalities.

CONCLUSIONS: Twenty-four percent of patients with idiopathic generalized epilepsies had MRI abnormalities. However, the majority of these abnormalities were nonspecific.