Incidental detection of hippocampal sclerosis on MR images: Is it significant?

BACKGROUND AND PURPOSE: The prevalence of hippocampal sclerosis in the gene ral nonepileptic patient population is not well described. While reports of its association with partial complex seizures are abundant, its absence in nonafflicted patients is generally presumed but not well documented, To te st the hypothesis that hippocampal sclerosis is specific for epilepsy, we r eviewed the MR imaging studies of 207 patients referred for hearing loss to determine whether high-resolution MR imaging could detect unsuspected hipp ocampal sclerosis in nonepileptic patients, METHODS: Our institution screens patients with hearing loss by using high-r esolution coronal and axial temporal bone MR imaging that includes the hipp ocampus within the imaging volume. We retrospectively reviewed 207 studies randomly selected from this database. RESULTS: The hippocampus was normal in 205 patients; in the remaining two p atients we identified one or more primary determinants for hippocampal scle rosis, Subsequent retrospective chart review revealed that both patients ha d had previously diagnosed seizure disorders, CONCLUSION: The imaging determinants of hippocampal sclerosis are not preva lent in nonepileptic patients, Incidental identification of hippocampal scl erosis on MR images is uncommon and significant, and should prompt further clinical investigation to exclude a seizure disorder.