Abstracts

Hippocampal atrophy (HA) in magnetic resonance images (MRI) is associated with refractory seizures in patients with mesial temporal lobe epilepsy (MTLE). It is still not clear if repeated epileptic seizures can precipitate or contribute to progressive hippocampal damage. The objective of this study was to evaluate hippocampal volume and the possibility of progression of HA in patients with MTLE by analyzing long-term follow-up MRI scans., Forty-nine patients underwent two MRI scans. Clinical data were collected retrospectively. All scans were analyzed by an investigator, blind for clinical data. Hippocampal volumetry was performed manually in 3mm thick coronal images, using the software NIH-Image, with correction for the variation of total intracranial volumes. Data was compared to those from a control group and HA was determined for hippocampal volumes below two standard deviations from the mean of control group. Hippocampal volumes were compared by paired t-test. Spearman[apos]s correlation was used to determine the association between the progressions of HA with clinical variables. The software Systat 9 was used for statistical analysis., The mean time between the two MRI scans was 45 months (SD=27; range=7 to 85 months). At the first image, 32 patients (65%) presented HA. Three patients with normal first MRI presented HA at the second scan. In the group analysis, there was a significant reduction of the right (p[lt]0.0001) and left (p[lt]0.0001) hippocampal volumes during the follow-up period. There was no correlation between the number of seizures presented in the period and the progression of hippocampal atrophy. History of febrile seizures, initial precipitating injury, status epilepticus or family history of epilepsy did not influenced hippocampal reduction between the two images., Hippocampal atrophy progresses over the years in patients with MTLE. This hippocampal reduction is not related to the number of seizures presented.,