1H-MR spectroscopy metabolite levels correlate with executive function in vascular cognitive impairment
- Charles Gasparovic1,
- Jillian Prestopnik2,
- Jeffrey Thompson2,
- Saeid Taheri2,3,
- Branko Huisa2,
- Ronald Schrader4,
- John C Adair2,
- Gary A Rosenberg2,5,6
- 1The Mind Research Network, Albuquerque, New Mexico, USA
- 2Department of Neurology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
- 3Department of Radiology and Radiological Sciences, Medical University South Carolina, Charleston, South Carolina, USA
- 4Clinical Translational Research Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
- 5Department of Neurosciences, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
- 6Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
- Correspondence to Dr G A Rosenberg, Department of Neurology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131-0001, USA;
- Received 13 August 2012
- Revised 13 January 2013
- Accepted 20 January 2013
- Published Online First 16 February 2013
Background White matter hyperintensities (WMHs) are associated with vascular cognitive impairment (VCI) but fail to correlate with neuropsychological measures. As proton MR spectroscopy (1H-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 1H-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.