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Cerebral N-acetylaspartate is low in patients with multiple sclerosis and abnormal visual evoked potentials
Purpose:
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.
Conclusion:
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.
Insights
In multiple sclerosis (MS) patients, N-acetylaspartate (NAA) levels in the brain
Area of Science:
- Neuroimaging
- Neuroscience
- Biochemistry
Background:
- Multiple sclerosis (MS) is a chronic neurological disease.
- Visual evoked potentials (VEPs) assess the integrity of the visual pathway.
- Cerebral metabolite changes may reflect MS-related neurodegeneration.
Purpose of the Study:
- To compare cerebral proton magnetic resonance (MR) metabolite changes in MS patients with abnormal VEPs versus those with normal VEPs.
- To investigate the sensitivity of specific metabolites to visual pathway dysfunction in MS.
Main Methods:
- Seventeen clinically definite MS subjects underwent VEP testing and MR spectroscopic imaging.
- Proton echo-planar spectroscopic imaging (PEPSI) measured N-acetylaspartate (NAA), choline, and creatine levels.
- Kurtzke's Expanded Disability Status Scale (EDSS) and MR-detectable lesion fractions were also assessed.
Main Results:
- Lower PEPSI NAA values were observed in MS patients with abnormal VEPs compared to those with normal VEPs.
- While MR-detectable lesion fractions and EDSS scores differed between VEP groups, NAA showed a statistically more significant difference.
- NAA levels were significantly reduced in the optic pathways of MS patients with abnormal VEPs.
Conclusions:
- N-acetylaspartate (NAA) measurements in the brain's optic pathways are sensitive to VEP abnormalities in MS.
- NAA is a more sensitive biomarker for VEP changes in MS than choline, creatine, MR-detectable lesions, or EDSS score.
- Proton MR spectroscopy, specifically NAA quantification, can aid in assessing visual pathway involvement in MS.
Related Concept Videos
01:19Multiple Sclerosis l: Introduction
01:22Cerebral Edema ll: Pathophysiology