1H-MRS imaging in intractable frontal lobe epilepsies characterized by depth electrode recording

Neuroimage. 2005 Jul 15;26(4):1174-83. doi: 10.1016/j.neuroimage.2005.03.023.

Abstract

Presurgical evaluation of frontal lobe epilepsy (FLE) remains a challenging issue and frequently requires invasive depth electrode recording. In this study, we aimed at evaluating the potential usefulness of a non-invasive technique such as proton magnetic resonance spectroscopic imaging ((1)H-MRSI) in the presurgical evaluation of FLE and at investigating the potential electrophysiological correlates of the metabolic disturbances as defined by (1)H-MRSI. We compared the distribution of (1)H-MRSI abnormalities with the electrophysiological abnormalities defined by stereo-electroencephalography (SEEG) recording in 12 patients presenting with several subtypes of FLE. We also used 12 control subjects in order to obtain normative (1)H-MRSI data. We used a multilevel (1)H-MRSI protocol to better sample the principal regions of the frontal lobe. We also applied a metabolic mapping technique allowing a visual display of metabolic data. A significant decrease of both N-acetyl-aspartate/phosphocreatine-creatine and N-acetyl-aspartate/(choline-compounds + phosphocreatine-creatine) ratios was observed in regions involved in the epileptogenic zone (EZ) and/or the irritative zone (IZ) compared to regions without electrical abnormalities in the same patients (P = 0.044 and P = 0.018, respectively), and also compared to controls (P = 0.004 and P = 0.0001, respectively). No significant differences in metabolic ratios were observed between those regions involved in the EZ and those involved in the IZ only. Our results suggest a link between the relative decrease of N-acetyl-aspartate and the EZ as well as the IZ in FLE. Thus, multilevel (1)H-MRSI protocol may add pertinent information during the non-invasive presurgical evaluation of FLE.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aspartic Acid / analogs & derivatives*
  • Aspartic Acid / metabolism
  • Brain Mapping
  • Choline / metabolism
  • Creatine / metabolism
  • Drug Resistance
  • Electrodes
  • Electroencephalography
  • Electrophysiology
  • Epilepsy, Frontal Lobe / metabolism
  • Epilepsy, Frontal Lobe / pathology*
  • Epilepsy, Frontal Lobe / physiopathology
  • Female
  • Frontal Lobe / metabolism
  • Frontal Lobe / pathology
  • Frontal Lobe / physiopathology
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Phosphocreatine / metabolism

Substances

  • Phosphocreatine
  • Aspartic Acid
  • N-acetylaspartate
  • Creatine
  • Choline