Abstracts

RATIONALE:The aim of this study was to investigate whether CSI high resolution multivoxel spectroscopy may improve the prediction of seizure outcome after the surgical treatment of temporal lobe epilepsy, and if there is a relation between MR spectroscopy and histopathological findings. METHODS:In 56 consecutive temporal lobe epilepsy patients scheduled for surgical treatment, MR spectroscopy was performed before and (at least 6 month) after surgery on a 1.5T MAGNETOM Vision (Siemens Erlangen) using a CSI-multi-voxel-technique. we examined the NAA/Cho-ratio in the temporal lobe by positioning the volume of interest in the hippocampal formation and the surrounding gray and white matter. A quantified histopathological examination was used in order to differentiate subtle cortical malformations. Outcome was assessed in all patients within an average postoperative period of 26 months. Additionally in 26 patients quantitative MR-Volumetry and T2-relaxometry was employed. RESULTS:In the lateralization of seizure onset, MR-spectroscopy showed a high correlation with the preoperative standard diagnosis (video-EEG, SPECT, MR). In patients with clear unilateral or only slight bilateral pathological CSI findings, seizure control was the most successful. Here histopathology showed mainly hippocampal sclerosis or low grad tumors. Patients with severe bilateral pathological CSI findings could not reach sufficient seizure control. Histopathologically in these patients mostly signs of cortical malformation were found. When the preoperative assessment showed slight contralateral pathological MRS findings the postoperative MRS examination was normal. CONCLUSIONS: Non-invasive information obtained by 1H-MRS may be useful for the preoperative assessment of pathological changes and also for the prognosis of outcome after epilepsy surgery in temporal lobe epilpesy.