(1)H-MRS profile in MRI positive- versus MRI negative patients with temporal lobe epilepsy

Seizure. 2008 Sep;17(6):490-7. doi: 10.1016/j.seizure.2008.01.008. Epub 2008 Mar 11.

Abstract

Introduction: The objective of this study was to quantitate and compare ipsilateral total N-acetyl aspartate (tNAA), creatine (Cr), choline (Cho), myo-inositol (m-Ins) and glutamate plus glutamine (Glx) levels in the hippocampi of patients with temporal lobe epilepsy (TLE) with and without magnetic resonance imaging (MRI) evidence for mesial temporal sclerosis (MRI positive/negative).

Patients and methods: Twenty-three age matched healthy controls and 26 consecutive patients with unilateral TLE, based on intensive 24h video-EEG, were investigated with proton magnetic resonance spectroscopy ((1)H-MRS) (17 with unilateral hippocampal sclerosis (HS) in MRI-MRI positive; 9 MRI negative). For statistical analysis one-way analysis of variance (ANOVA) with post hoc multiple comparisons and Bonferroni correction was applied. The significance level was based on p<0.05.

Results: The mean tNAA level ipsilateral to the seizure focus was significantly decreased in MRI negative, respectively MRI positive patients in comparison to healthy controls (p<0.001). The lowest tNAA level was noticed in the MRI positive group (p<0.001). Statistical analysis highlighted a clear "tNAA cut-off" (95% confidence interval) between MRI positive- and MRI negative patients and healthy controls. Mean level of Glx and m-Ins was not significantly elevated or reduced. However, in individual cases a significant elevation was noticed for Glx in MRI negative patients, respectively for m-Ins in MRI positive patients.

Conclusion: MRI negative TLE patients have a different MRS profile than MRI positive patients (HS) with marginal but significant decrease of tNAA. Our results reveal a clear "tNAA cut-off" between the groups. The value of m-Ins and Glx in focus detection in TLE patients remains controversy.

MeSH terms

  • Adult
  • Analysis of Variance
  • Aspartic Acid / analogs & derivatives
  • Creatine
  • Electroencephalography
  • Epilepsy, Temporal Lobe / diagnosis*
  • Epilepsy, Temporal Lobe / physiopathology
  • Female
  • Glutamic Acid / metabolism
  • Glutamine / metabolism
  • Hippocampus / pathology
  • Humans
  • Inositol / metabolism
  • Magnetic Resonance Imaging*
  • Magnetic Resonance Spectroscopy / methods*
  • Male
  • Middle Aged
  • Protons*
  • Sclerosis / pathology

Substances

  • Protons
  • Glutamine
  • Aspartic Acid
  • Glutamic Acid
  • Inositol
  • N-acetylaspartate
  • Creatine