Cerebral N-acetylaspartate is low in patients with multiple sclerosis and abnormal visual evoked potentials.
OBJECTIVE
Our purpose was to compare cerebral proton MR metabolite changes in patients with multiple sclerosis (MS) and abnormal visual evoked potentials (VEPs) with those in MS patients with normal VEPs.


METHODS
Seventeen subjects with clinically definite MS were studied with VEPs and MR spectroscopic imaging. Proton MR metabolites were measured using a fast spectroscopic imaging technique called proton echo-planar spectroscopic imaging (PEPSI). Kurtzke's Expanded Disability Status Scale (EDSS) score was also ascertained for each subject to obtain a clinical rating. Twelve regions of interest within the visual pathway of the cerebrum were evaluated for levels of N-acetylaspartate (NAA), choline, creatine, and the presence or absence of MR-detectable lesions.


RESULTS
PEPSI NAA values (water-normalized, CSF-corrected) were significantly lower in MS subjects with abnormal VEPs than in subjects with normal VEPs. MR-detectable lesion fractions and EDSS scores were also significantly different between the two VEP groups, but NAA comparison had a P value 100 times less than either of these measures.


CONCLUSIONS
In patients with MS, NAA measurements in the optic pathways of the brain were sensitive to VEP abnormalities. NAA was more sensitive to VEP changes than were choline, creatine, MR-detectable lesions, and EDSS score.
Heide
A C
AC
Department of Radiology, University of Washington, Seattle, USA.
Kraft
G H
GH
Slimp
J C
JC
Gardner
J C
JC
Posse
S
S
Serafini
S
S
Bowen
J D
JD
Richards
T L
TL
D000328:Adult; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D001931:Brain Mapping; D002794:Choline / Q000378:metabolism; D003401:Creatine / Q000378:metabolism; D004185:Disability Evaluation; D017352:Echo-Planar Imaging; D004569:Electroencephalography; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009103:Multiple Sclerosis / Q000175:diagnosis* / Q000503:physiopathology; D009460:Neurologic Examination; D009471:Neuromyelitis Optica / Q000175:diagnosis* / Q000503:physiopathology; D009778:Occipital Lobe / Q000473:pathology / Q000503:physiopathology; D012815:Signal Processing, Computer-Assisted; D014795:Visual Pathways / Q000473:pathology / Q000503:physiopathology
D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline