In Vivo Detection of Postictal Perturbations of Cerebral Metabolism by Use of Proton MR Spectroscopy: Preliminary Results in a Canine Model of Prolonged Generalized Seizures

animals have monitored postictal perturbations in cerebral metabolism with either invasive techniques or with such noninvasive techniques as nuclear medicine, MR imaging, in vivo phosphorus MR spectroscopy (MRS), and in vivo proton MRS at field strengths of 1.5 T or above. We investigated postictal metabolic changes in a generalized seizure model with in vivo proton MRS at 0.5 T, in which the combination of glutamate and glutamine resonances (de-noted glx) can be modeled as a singlet. METHODS: Five adult mongrel dogs underwent control and postictal experiments in which single-voxel proton MR spectra were obtained from the right frontal lobe cortex with a point-resolved spectroscopy technique approximately every 20 minutes for 3 hours. N-acetylaspartate (NAA), glx, and creatine (Cr) were quantified in absolute millimolar units with a cerebral water-referenced algorithm. Inter- and intrasubject differences in mean metabolite concentra-tions collected throughout the 3-hour period were compared using an unpaired, two-tailed Student’s t test at a.05 level of significance. RESULTS: We found a significant increase (15.4%) in the postictal intersubject mean glx concentration, as well as a 23.7 % postictal decrease in the intersubject mean Cr concentration