MR IN TEMPORAL-LOBE EPILEPSY - ANALYSIS WITH PATHOLOGICAL CONFIRMATION

PURPOSE: We evaluated the MR findings in patients with temporal lobe e pilepsy to determine the predictive value of MR imaging in assessing p atient outcome. METHODS: MR studies from 186 of 274 consecutive patien ts who underwent temporal lobectomy for intractable epilepsy were revi ewed retrospectively, Images were interpreted by an experienced neuror adiologist, who was blinded to the side of seizure activity and to pat hologic findings. RESULTS: MR imaging exhibited 93% sensitivity and 83 % specificity in detecting hippocampal/amygdalar abnormalities (n = 12 1), and 97% sensitivity and97% specificity in detecting abnormalities in the rest of the temporal lobe (n = 60), Abnormal high signal of the hippocampus on T2-weighted images had a sensitivity of 93% and specif icity of 74% in predicting mesial temporal sclerosis (n = 115), The pr esence of hippocampal atrophy on MR correlated with the duration of se izures, Sensitivity and specificity of MR imaging in detecting tempora l lobe tumors (n = 42) were 83% and 97%, respectively, based on abnorm al signal and mass effect, After surgery, 63% of patients were seizure free and 28% had a significant reduction of seizure frequency at an a verage of 24 months (range, 12 to 78 months) after surgery. Patients w ith a single lesion in the anterior temporal lobe or hippocampus/amygd ala had a better outcome than patients with multiple lesions (n = 22), Interrater agreement varied from 0.4 to 0.93, with best agreement for tumors or abnormal hippocampal signal on T2-weighted images. CONCLUSI ON: MR imaging is highly sensitive in detecting and locating abnormali ties in the temporal lobe and the hippocampus/amygdala in patients wit h temporal lobe epilepsy, Hippocampal atrophy appears to correspond to the duration of seizure disorder.