PROTON NR SPECTROSCOPY IN PATIENTS WITH SEIZURE DISORDERS

PURPOSE: To evaluate the ability of proton MR spectroscopy to detect m etabolic abnormalities in the seizure focus of humans with epilepsy. M ETHODS: Single-voxel MR spectroscopy and MR imaging was performed in a group of 13 patients with a variety of seizure disorders and in the t emporal lobes of 14 healthy volunteers. Signals from choline, creatine , N-acetyl-L-aspartate, and lactate were quantitated in both the epile ptogenic focus and the contralateral brain region. RESULTS: In normal temporal lobe, concentrations of choline, creatine, and N-acetyl-L-asp artate were 2.0 +/- 0.7, 7.8 +/- 1.9, and 11.0 +/- 2.1 mu mol/g wet we ight, respectively, with no detectable lactate. In all patients, a red uction in the N-acetyl-L-aspartate signal was observed in the electric ally defined (scalp electroencephalogram) seizure focus compared with the mirror-image contralateral side. Lactate was elevated only in pati ents who had seizures during or immediately before the MR examination. Seven of 13 patients studied had normal MR examinations. CONCLUSIONS: Proton spectroscopy demonstrates alterations in N-acetyl-L-aspartate and lactate levels that can be used to locate the epileptogenic focus and may be a useful adjunctive diagnostic technique for the evaluation of patients with seizures who are eligible for resective surgery.