CLINICAL-APPLICATIONS OF MAGNETIC-RESONANCE SPECTROSCOPY

Magnetic resonance spectroscopy (MRS) is a new tool for evaluation of patients with epilepsy, demonstrating abnormalities of energy and lipi d metabolism ictally and, more recently, interictally. These metabolic abnormalities include increased inorganic phosphate, pH, and decrease d phosphomonoesters as determined by P-31 MRS, as well as decreased N- acetylaspaaate determined by H-1 MRS. Furthermore, increased lactic ac id has been detected postictally. These metabolic changes appear to be confined to the region of seizure origination and can be detected int erictally. Therefore, they can be used for lateralization of the epile ptogenic focus. Ongoing research suggests that these abnormalities may also be useful in localization of the focus, demonstrating metabolic alterations in temporal lobe epilepsy (TLE) similar to those in neocor tical epilepsy. However, further technical development will be require d before the goal of using these techniques for localization of the ep ileptogenic focus can be realized. For TLE lobe epilepsy at least, the clinical utility of H-1 MRS to lateralize the seizure focus has clear ly been demonstrated by several centers. The consistent findings in TL E suggest that H-1 MRS is ready to become part of the evaluation proce ss of patients with medically refractory epilepsy being evaluated for seizure surgery.