In fourteen patients suffering from pharmacoresistent epilepsy with partial complex seizures H-1 MR spectra from the left and right hippocampus were assessed, From the ratios NAA/Cr, NAA/Cho and NAA/(Cr + Cho) the asymmetry coefficient was calculated which characterizes the reduced NAA concentration in the assumed epileptogenic focus. Agreement between MRS and the EEG finding was found in 10 of 14 cases, i.e. in 71%.
MR spectroscopy is therefore another non-invasive diagnostic method suitable for assessment of lateralization of an epileptic focus before epilepto-surgery.