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, magnet ic resonance imaging (MRI) frequently demonstrates hippocampal atrophy and increased hippocampal signal. To assess the prognostic value of t hese findings, we studied 51 patients evaluated prospectively by a rad iologist blinded to other preoperative evaluations. Thirty-one of 51 ( 61%) patients undergoing temporal lobectomy had visually apparent hipp ocampal 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 pa tients with normal scans [24 of 25 (96%) vs. 10 of 20 (50%) p < 0.015] . Both ipsilateral hippocampal atrophy and ipsilateral increased hippo campal signal independently predicted a seizure-free outcome. Qualitat ive MRI provides important prognostic information in patients undergoi ng temporal lobectomy.