Abstracts

Successful epilepsy surgery of the temporal lobe has been associated with mesial temporal lobe MRI abnormalities. We retrospectively reviewed different findings to establish their value in predicting post-operative seizure outcome.
We retrospectively created a database containing the pre-operative and post-operative findings of over 250 epilepsy surgeries beginning in 1991. We queried the database to identify patients with complete cranial MRI information and [gt] 6 months of post-operative seizure frequency information. We specifically encoded MRI findings of hippocampal atrophy, temporal horn enlargement, and hippocampal sclerosis and analyzed their relationship to seizure-freedom or continued post-operative seizures.
Our database contained 267 surgical cases and 162 temporal lobectomies. Complete MRI and 6 month post-operative seizure outcome data was present in 140 patients. Seizure freedom was seen in 70% of the group overall. Seizure freedom with temporal horn enlargement, hippocampal atrophy, and hippocampal sclerosis were 68%, 67%, and 70%, respectively. Seizure freedom was statisitically significantly associated with temporal horn enlargement (p[lt]0.009, Pearson[apos]s Chi Squared) and hippocampal sclerosis (p[lt]0.010). Assessments of hippocampal atrophy did not show a statistically significant prediction of seizure freedom (p=0.847).
We found hippocampal sclerosis and temporal horn enlargement associated with successful temporal lobe surgery for epilepsy. Success for the group was overall good and the lack of an effect from hippocampal atrophy may reflect the qualitative versus quantitative techniques used when data collection started in 1990. We weight MRI findings for surgical selection today with these findings and believe quantitative MRI assessment of hippocampal volume would likely support its predictive value as well.