MAGNETIC-RESONANCE SPECTROSCOPY IN TEMPORAL-LOBE EPILEPSY

We used proton magnetic resonance spectroscopy (H-1 MRS) to investigat e the temporal lobes of 25 patients with temporal lobe epilepsy. Spect ra were obtained from 2 x 2 x 2 cm cubes in the medial region of the t emporal lobe, and were analyzed on the basis of signals from N-acetyla spartate (NAA), creatine + phosphocreatine (Cr), and choline-containin g compounds (Cho). In comparison with control subjects, the temporal l obes ipsilateral to the seizure focus showed a mean reduction of 22% i n the NAA signal, with a 158 increase in the Cr signal and a 25% incre ase in the Cho signal. There were smaller effects in the contralateral temporal lobes. These spectral abnormalities may reflect neuronal los s or damage, together with reactive astrocytosis. The NAA/Cho+Cr ratio was abnormally low in 88% of the patients, 40% showing bilateral effe cts. On the basis of the NAA/Cho+Cr ratio, pre correctly achieved late ralization in 15 cases, with three incorrect. Two of the incorrect lat eralizations also had imaging abnormalities on the contralateral side, and the other had severe bilateral abnormalities on MRS, We conclude that 1H MRS provides useful information in the preoperative investigat ion of patients with temporal lobe epilepsy, contributing to lateraliz ation and detecting bilateral abnormalities.