Prognostic value of qualitative magnetic resonance imaging hippocampal abnormalities in patients undergoing temporal lobectomy for medically refractory seizures.

In patients with temporal lobe epilepsy (TLE), high-resolution, magnetic resonance imaging (MRI) frequently demonstrates hippocampal atrophy and increased hippocampal signal. To assess the prognostic value of these findings, we studied 51 patients evaluated prospectively by a radiologist blinded to other preoperative evaluations. Thirty-one of 51 (61%) patients undergoing temporal lobectomy had visually apparent hippocampal atrophy or increased hippocampal signal on MRI (25 ipsilateral 3 contralateral, and 3 bilateral to the operated site). Patients with ipsilateral abnormalities became seizure-free more frequently than patients with normal scans [24 of 25 (96%) vs. 10 of 20 (50%) p < 0.015]. Both ipsilateral hippocampal atrophy and ipsilateral increased hippocampal signal independently predicted a seizure-free outcome. Qualitative MRI provides important prognostic information in patients undergoing temporal lobectomy.