1H-MR spectroscopy metabolite levels correlate with executive function in vascular cognitive impairment
Charles Gasparovic1, Jillian Prestopnik, Jeffrey Thompson
1Department of Neurology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131-0001, USA.
Background:
White matter hyperintensities (WMHs) are associated with vascular cognitive impairment (VCI) but fail to correlate with neuropsychological measures. As proton MR spectroscopy ((1)H-MRS) can identify ischaemic tissue, we hypothesised that MRS detectable brain metabolites would be superior to WMHs in predicting performance on neuropsychological tests.
Methods:
60 patients with suspected VCI underwent clinical, neuropsychological, MRI and CSF studies. They were diagnosed as having subcortical ischaemic vascular disease (SIVD), multiple infarcts, mixed dementia and leukoaraiosis. We measured brain metabolites in a white matter region above the lateral ventricles with (1)H-MRS and WMH volume in this region and throughout the brain.
Results:
We found a significant correlation between both total creatine (Cr) and N-acetylaspartyl compounds (NAA) and standardised neuropsychological test scores. Cr levels in white matter correlated significantly with executive function (p=0.001), attention (p=0.03) and overall T score (p=0.007). When lesion volume was added as a covariate, NAA also showed a significant correlation with executive function (p=0.003) and overall T score (p=0.015). Furthermore, while metabolite levels also correlated with total white matter lesion volume, adjusting the Cr levels for lesion volume did not diminish the strength of the association between Cr levels and neuropsychological scores. The lowest metabolite levels and neuropsychological scores were found in the SIVD group. Finally, lesion volume alone did not correlate significantly with any neuropsychological test score.
Conclusion:
These results suggest that estimates of neurometabolite levels provide additional and useful information concerning cognitive function in VCI not obtainable by measurements of lesion load.
Insights
Brain metabolite levels, measured by proton MR spectroscopy, better predict cognitive function in vascular cognitive impairment (VCI) than white matter hyperintensities (WMHs). This finding offers new insights into VCI assessment.
Area of Science:
- Neuroimaging
- Neurology
- Biochemistry
Background:
- White matter hyperintensities (WMHs) are linked to vascular cognitive impairment (VCI) but show weak correlations with cognitive tests.
- Proton MR spectroscopy ((1)H-MRS) can detect ischemic changes in brain tissue.
Purpose of the Study:
- To investigate if brain metabolites detected by (1)H-MRS are superior to WMHs in predicting neuropsychological test performance in patients with suspected VCI.
Main Methods:
- Sixty patients with suspected VCI underwent clinical, neuropsychological, MRI, and CSF assessments.
- (1)H-MRS was used to measure brain metabolites in white matter; WMH volume was also quantified.
- Patients were diagnosed with subcortical ischemic vascular disease (SIVD), multiple infarcts, mixed dementia, or leukoaraiosis.
Main Results:
- Significant correlations were found between creatine (Cr) and N-acetylaspartyl compounds (NAA) and neuropsychological test scores.
- Cr levels correlated with executive function and attention; NAA correlated with executive function.
- Lesion volume alone did not significantly correlate with any neuropsychological test score, while metabolite levels did.
Conclusions:
- Neurometabolite levels provide valuable information about cognitive function in VCI.
- This information is not fully captured by lesion load measurements.
- Lower metabolite levels and cognitive scores were observed in the SIVD group.
