INTRACTABLE FRONTAL-LOBE EPILEPSY - PATHOLOGICAL AND MRI FEATURES

The clinical, pathological, and at least one year follow-up of 48 pati ents with intractable frontal lobe partial epilepsy who underwent surg ical treatment for their seizure disorder were reviewed. The group con sisted of 27 males and 21 females. Preoperative magnetic resonance ima ging (MRI) was normal (26 patients), demonstrated focal frontal lobe ( 16 patients) or multilobar signal abnormalities (6 patients). Postoper atively patients were divided into one of four groups based upon the d egree of seizure activity (Class I: seizure free, Class IV: little to no improvement, Classes II/III: intermediate). Eight patients with tum ors (low grade gliomas) were Class I (N = 6) or Class II (N = 2) posto peratively. The remaining six patients with focal, completely resected pathological lesions (e.g. tubers, contusions, etc.) also had Class I or Class II outcomes. Of the 31 patients with the pathological diagno sis of gliosis, the outcome was dependent on the MRI appearance. Preop erative MRI scans of these patients were normal (N = 23), or had focal frontal lobe (N = 2) or multilobar (N = 6) abnormalities. The gliosis patients with unilateral frontal MRI lesions had a good outcome (Clas s I or II) while those with multilobar MRI abnormalities were all Clas s IV. Successful outcome correlated strongly with both focal frontal l obe MRI and pathological abnormalities in contrast to the less favorab le results seen in patients with normal head MRI scans and gliosis or no pathological abnormality on pathological examination. Multilobar MR I abnormalities invariably had the poorest outcome of all patient grou ps. Thus presurgical MRI is an important tool and predictor of surgica l outcome in patients with frontal lobe epilepsy.