Magnetic resonance imaging and clinical and electroencephalographical localization in focal epilepsy

Magnetic Resonance Imaging (MRI) is the method of choice to search for epileptogenic lesions. We correlated MRI findings with the epileptogenic zone (EZ) depicted by clinical and electroencephalographic (EEG) data. We studied 400 clinical records of patients who had been submitted to MRI studies and we analyzed, retrospectively, their ictal semiology, EEG characteristics and response to treatment. They were classified into 3 groups: A) temporal lobe epilepsy, B) frontal lobe epilepsy and C) parieto-occipital epilepsy. We included 155 patients: Group A) 68 cases (43.9%), 28 men (41.1%), mean age 32 +/- 11 years old, abnormal (MR in 44 (64.7%), refractory to treatment 48 (70.5%). Group B) 68 cases (43.9%), 38 men (55.8%), mean age 30 +/- 15 years old, abnormal IMR in 26 (38.2%), refractory to treatment 30 (44.1%). Group C) 19 cases (12.2%), 13 men (68.4%), mean age 27 +/- 11 years old, abnormal IMR in 11 (57.8%), refractory to treatment 12 (63.1%). Results showed that there were higher possibilities of detecting lesions which correlate with EZ in temporal than in frontal or parieto-occipital lobes epilepsy. The chances to find abnormalities on the MRI were 5 times higher in refractory patients than in those who were non-refractory.