title: (1)H-MRS profile in MRI positive- versus MRI negative patients with temporal lobe epilepsy.
abstract: BACKGROUND
  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).
  
  
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Neuroradiology, University of Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen, Germany. marc.doelken@uk-erlangen.de
authors.forename: M T
authors.initials: MT
authors.lastname: Doelken
authors.forename: H
authors.initials: H
authors.lastname: Stefan
authors.forename: E
authors.initials: E
authors.lastname: Pauli
authors.forename: A
authors.initials: A
authors.lastname: Stadlbauer
authors.forename: T
authors.initials: T
authors.lastname: Struffert
authors.forename: T
authors.initials: T
authors.lastname: Engelhorn
authors.forename: G
authors.initials: G
authors.lastname: Richter
authors.forename: O
authors.initials: O
authors.lastname: Ganslandt
authors.forename: A
authors.initials: A
authors.lastname: Doerfler
authors.forename: T
authors.initials: T
authors.lastname: Hammen
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001224:Aspartic Acid / Q000031:analogs & derivatives; D003401:Creatine; D004569:Electroencephalography; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis* / Q000503:physiopathology; D005260:Female; D018698:Glutamic Acid / Q000378:metabolism; D005973:Glutamine / Q000378:metabolism; D006624:Hippocampus / Q000473:pathology; D006801:Humans; D007294:Inositol / Q000378:metabolism; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011522:Protons; D012598:Sclerosis / Q000473:pathology
chemical_list: D011522:Protons; D005973:Glutamine; D001224:Aspartic Acid; D018698:Glutamic Acid; D007294:Inositol; C000179:N-acetylaspartate; D003401:Creatine