N-acetylaspartate, choline, myoinositol, glutamine and glutamate (glx) concentration changes in proton MR spectroscopy ((1)H MRS) in patients with mild cognitive impairment (MCI)

BACKGROUND: Purpose of study was evaluation of regional metabolic disorders using (1)H MRS in patients with MCI, as a predictor of clinical conversion to dementia based on clinical follow-up. MATERIAL/METHODS: The study group consisted of 31 subjects with diagnosis of MCI based on criteria the Mayo Clinic Group. (1)H MRS was performed with a single-voxel method using PRESS sequence. The volume of interest (VOI) was located in the hippocampal formation and posterior part of the cingulated gyrus. RESULTS: Patients had annual clinical control at least twice. At the beginning, 9 had amnestic MCI and the others had multidomain MCI. During follow-up (median 3 yrs) 8 subjects had stable disease (SD), 13 had disease progression (DP) and 10 develop Alzheimer disease (AD). Baseline metabolic ratios ((1)H MRS) between 3 groups indicated significant difference (P<0.05) in left frontal lobe in mI/H(2)0 ratio, between patients with SD (0.27) and DP. In comparing the groups with DP and AD, a significant difference in NAA/Cr (1.77 vs. 1.43) was found. A significant difference within left temporal external lobes was found between SD and DP in NAA/H(2)O ratio (0.55 vs. 0.51). An additional significant difference within medial temporal lobe was found between DP and AD in Glx/H(2)O ratio (0.44 vs. 0.34) on the right side. CONCLUSIONS: (1)H MRS seems to be sensitive method allows prediction of which patients are liable to progress from MCI to AD. Combined with other biomarkers of disease staging, it is an important approach in the preclinical AD diagnosis, as well as the assessment of dementia progression.