Application of Spectroscopy to Epilepsy

  • K. D. Laxer
  • J. W. Hugg
  • G. B. Matson
  • M. W. Weiner
Part of the NATO ASI Series book series (NSSA, volume 264)

Abstract

A variety of imaging techniques have been used to characterise the ictal and inter-ictal metabolic abnormalities associated with focal epilepsy. Position emission tomography (PET) and SPECT scanning have demonstrated the inter-ictal focus to be hypoperfused and hypometabolic. Magnetic resonance spectroscopy (MRS) allows the non-invasive measuring of chemicals within the body and can be performed on many conventional MRI systems. MRS exploits the principle that every chemically distinct nucleus in a compound resonates at a slightly different frequency. Nuclear magnetic resonance (NMR) signals from many compounds can be detected simultaneously in one MRS experiment and magnetic resonance spectroscopic imaging (MRSI) with phase encoding has the ability to obtain MRS signals from multiple regions simultaneously. 1H MRS detects N-acetylaspartate (NAA), lactate, choline, creatine/phosphocreatine, and amino acids including glutamate, glutamine, aspartate and taurine. 31P MRS detects phosphocreatine (PCr), ATP, inorganic phosphate (Pi), pH (from the chemical shift of Pi), free Mg2+ (from the chemical shift of ATP), phosphomonoesters (PME), and phosphodiesters (PDE). PCr, ATP, Pi, pH and lactate provide information concerning bioenergetics. PDE, PME and choline provide information regarding lipid metabolism (Matson and Weiner, 1992). MRS studies in animals and in human neonates during seizures have confirmed previously reported alterations in energy metabolism including the depletion of PCr, ATP, and increased Pi, lactate and H+ (Young et al., 1985; Younkin et al., 1986). With the recognised metabolic abnormalities detected by PET and SPECT scanning inter-ictally, we questioned whether or not 1H and 31P MRS could document focal metabolic changes localised to the seizure focus which led to the following pilot studies.

Keywords

Phosphorus Lactate Glutamine Neurol Choline 

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References

  1. Hugg, J. W., Laxer, K. D., Matson, G. B., Maudsley, A. A., Husted, CA., and Weiner, M. W., 1992, Lateralisation of human focal epilepsy by 31P magnetic resonance spectroscopic imaging, Neurology 42: 2011–2018.PubMedCrossRefGoogle Scholar
  2. Hugg, J. W., Laxer, K. D., Matson, G. B., Maudsley, A. A., and Weiner, M. W., 1993, Neuron loss localizes human temporal lobe epilepsy by in-vivo proton magnetic resonance, Ann Neurol. 34: 788–794PubMedCrossRefGoogle Scholar
  3. Laxer, K. D., Hubesch, B., Sappey-Marinier, D. and Weiner, M. W., 1992, Increased pH and inorganic phosphate in temporal seizure foci, demonstrated by 31P MRS, Epilepsia 33: 618–623.PubMedCrossRefGoogle Scholar
  4. Matson, G. B., and Weiner, M. W., 1992, Spectroscopy, in: “MRI,” D. D. Stark, and W. G. Bradley, eds, C. V. Mosby Yearbook, St. Louis.Google Scholar
  5. Ryvlin, P., Philippon, B., Cinotti, L., Froment, J. C., Le Bars, D., and Mauguiere, F., 1992, Functional neuroimaging strategy in temporal lobe epilepsy: a comparative study of 18FDG-PET and 99mTc-HMPAO-SPECT, Ann Neurol. 31: 650–656.PubMedCrossRefGoogle Scholar
  6. Young, R. S., Osbakken, M. D., Briggs, R. W., Yagel, S. K., and Rice, D. W., 1985, 31P NMR study of cerebral metabolism during prolonged seizures in the neonatal dog, Ann Neurol. 18: 14–20.PubMedCrossRefGoogle Scholar
  7. Younkin, D. P., Delivoria-Papadopoulos, M., Maris, J., Donlon, E., Clancy, R., and Chance, B., 1986, Cerebral metabolic effects of neonatal seizures measured with in vivo 31P NMR spectroscopy, Ann Neurol. 20: 513–519.PubMedCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 1994

Authors and Affiliations

  • K. D. Laxer
    • 1
  • J. W. Hugg
    • 1
  • G. B. Matson
    • 1
  • M. W. Weiner
    • 1
  1. 1.University of CaliforniaSan FranciscoUSA

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