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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. AJNR Am J Neuroradiol 2001 Nov-Dec;22(10):1933-43

Date

12/06/2001

Pubmed ID

11733328

Pubmed Central ID

PMC7973822

Scopus ID

2-s2.0-0035179010   25 Citations

Abstract

BACKGROUND AND PURPOSE: Biochemical studies of seizures in patients and laboratory 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 (denoted 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 concentrations 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. A trend toward a subtle decrease in postictal intersubject mean NAA concentration was not statistically significant. We also observed a substantial qualitative increase in the combination of postictal lactate and free fatty acid peaks.

CONCLUSIONS: The glx, NAA, lactate, and free fatty acid results are in general agreement with previous studies of postictal perturbations in cerebral metabolism measured with invasive biochemical or noninvasive high-field-strength in vivo MRS detection assays. Given a high sensitivity for glx at 0.5 T relative to 1.5 T, further studies of postictal mesial temporal lobe structures are warranted in chronic animal preparations that model temporal lobe epilepsy.

Author List

Neppl R, Nguyen CM, Bowen W, Al-Saadi T, Pallagi J, Morris G, Mueller W, Johnson R, Prost R, Rand SD

Author

Wade M. Mueller MD Professor in the Neurosurgery department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Animals
Aspartic Acid
Convulsants
Creatine
Dogs
Fatty Acids, Nonesterified
Female
Frontal Lobe
Glutamic Acid
Glutamine
Lactic Acid
Magnetic Resonance Spectroscopy
Male
Pentylenetetrazole
Seizures