In vivo measurements of glutamine + glutamate (Glx) and N-acetyl aspartate (NAA) levels in human partial epilepsy.
OBJECTIVE
To investigate whether cerebral levels of N-acetyl aspartate (NAA), and glutamine + glutamate (Glx), are interictally altered in the epileptogenic regions of patients with partial seizures.


METHODS
NAA, Glx, creatine (Cr), choline (Cho) and myo-inositol (mI) was measured in 28 patients with partial epilepsy and 10 healthy controls using localized 1H magnetic resonance spectroscopy. According to the multimethodological consensus, the epileptogenic region was mesial temporal in 18 and neocortical in 10 patients.


RESULTS
The Glx/NAA and Glx/Cr ratios in epileptogenic regions were higher, and the NAA/Cr ratios lower than in the homologous regions (P=0.013, P=0.002 and P<0.0001). Applying the 95% confidence interval of controls, 17 of the 20 mesial temporal epileptogenic regions were correctly identified by an increased Glx/NAA and 15 of 20 by a decreased NAA/Cr ratio. Among patients with neocortical epilepsy the Glx/NAA ratio was increased in 8 of the 10 epileptogenic regions, whereas the NAA/Cr ratio was decreased in three.


CONCLUSIONS
Both Glx and NAA are useful to identify the epileptogenic zone. The Glx/NAA ratios may be particularly useful to indentify neocortical epileptogenic regions.
Savic
I
I
Dept of Neurology, UCLA, Los Angeles, USA. ivanka.savic-berglund@neuro.ki.se
Thomas
A M
AM
Ke
Y
Y
Curran
J
J
Fried
I
I
Engel
J
J
D000293:Adolescent; D000328:Adult; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D015415:Biomarkers; D001921:Brain / Q000378:metabolism* / Q000473:pathology; D016022:Case-Control Studies; D003401:Creatine / Q000378:metabolism*; D003937:Diagnosis, Differential; D004828:Epilepsies, Partial / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D005260:Female; D018698:Glutamic Acid / Q000378:metabolism*; D005973:Glutamine / Q000378:metabolism*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D019579:Neocortex / Q000473:pathology; D013702:Temporal Lobe / Q000473:pathology
D015415:Biomarkers; D005973:Glutamine; D001224:Aspartic Acid; D018698:Glutamic Acid; C000179:N-acetylaspartate; D003401:Creatine