Abstracts

Rationale: The epileptic activity emanating from an epileptogenic lesion causes widespread changes in the grey and white matter in the human brain. We previously reported that functional improvement occurs in the remote projection areas after an epileptogenic area was selectively resected in patients with mesial temporal lobe epilepsy (Takaya et al., Brain 2009: 132; 185-194). However, plastic changes in white matter architecture after selective removal of an epileptogenic region have not been reported. The purpose of the current study was to investigate whether the white matter integrity improves after subtemporal selective amygdalohippocampectomy in patients with intractable mesial temporal lobe epilepsy. Methods: We studied 7 consecutive patients with medically intractable mesial temporal lobe epilepsy with unilateral hippocampal sclerosis. Diffusion tensor images (DTI) were acquired using 3T MRI before and after subtemporal selective amygdalohippocampectomy. Postoperative change in diffusion tensor parameters were evaluated using tract-based spatial statistics (TBSS) implemented in FSL.This study was approved by the Ethics Committee of the Kyoto University Graduate Schoool of Medicine, and informed consent was obtained from all patiens. Results: All patients were seizure-free following subtemporal amygdalohippocampectomy. Post operative fractional anisotropy was increased in the fronto-parietal areas contralateral to the resected region and reduced in the temporal lobe ipsilateral to the resected region. Conclusions: This study suggests that the white matter integrity might improve in the brain regions remote from the epileptic focus after the selective removal of an epileptogenic lesion. Funding: This study was supported by grans from the Japan Epilepsy Research Foundation and Japan Brain Foundation, and Health and Labour Sciences Research Grants for the Research on Pshychiatric and Neurological Diseases and Mental Health from the Ministry of Health, Labor and Welfare.