MAGNETIC-RESONANCE-IMAGING AND SPECTROSCOPY FINDINGS AFTER FOCAL STATUS EPILEPTICUS

The etiology of cerebral abnormalities after focal status epilepticus (SE) is unknown. Possible causes include hypoxia and the excessive rel ease of excitatory amino acids. Magnetic resonance imaging (MRI) of a 21-year-old patient with ''cryptogenic'' continuous motor seizures sho wed swelling and signal hyperintensity of the contralateral parietotem poral cortex, the thalamus, and the ipsilateral cerebellum on T-2-weig hted images. These regions are connected by glutamatergic pathways. Pr oton magnetic resonance spectroscopy (MRS) of the cortical lesion yiel ded a signal peak at the resonance frequency of 2.29 ppm, suggesting a focal increase of glutamate or its degradation product glutamine. At 3-month follow-up, structural alterations had disappeared, but the N-a cetyl-aspartate/choline ratio was still reduced in the previously abno rmal area, These findings are the first to demonstrate the contributio n of MRS to pathophysiologic studies of focal SE in humans and, in com bination with the pattern of imaging abnormalities, support a major ro le of glutamate for seizure-related brain damage.