Proton magnetic resonance spectroscopy in mild cognitive impairment and Alzheimer's disease: a preliminary study.

BACKGROUND

Mild cognitive impairment (MCI) is recognized as a transitional clinical state between normal aging and Alzheimer's disease (AD) and has significant higher rate of progression to AD.

OBJECTIVE

To compare the changes of metabolites between AD and MCI in specific locations of the brain by using Magnetic Resonance Spectroscopy (MRS).

MATERIAL AND METHOD

MMSE-Thai 2002 and neuropsychological test were performed in 17 patients with memory problem, classified into AD and MCI (10, 7 patients respectively). All patients and three age-matched cognitively normal volunteers were examined with conventional MRI and MRS of the brain. Volumes of interest were located at both-sided frontal and parietal deep white matter. NAA/Cr, Cho/Cr and mI/Cr ratios of the patients were analyzed and statistically evaluated relative to cognitively normal volunteers. Statistical analysis was performed using Cohen's kappa coefficient and Kruskal-Wallis test.

RESULTS

There was no statistically significant change in metabolites in all brain regions. For AD relative to cognitively normal volunteers, there were strong tendency toward statistically significant decreased NAA/Cr at the left frontal and left parietal regions (p = 0.043 each) and decreased Cho/Cr at the left frontal region (p = 0.028).

CONCLUSION

The changes of the metabolite ratios of MCI were much closer to AD. Strong tendency toward statistically significant decreased NAA/Cr in the left cerebral hemisphere, predominantly parietal region and strong tendency toward statistically significant decreased Cho/Cr at the left frontal region were indicative of neurodegeneration and replacement by gliosis. MRS may be useful for predict a chance that cognitively normal people may convert to the AD.