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

Abstract

SummaryBackgroundPurpose of study was evaluation of regional metabolic disorders using 1H MRS in patients with MCI, as a predictor of clinical conversion to dementia based on clinical follow-up.Material/MethodsThe study group consisted of 31 subjects with diagnosis of MCI based on criteria the Mayo Clinic Group. 1H 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.ResultsPatients 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 (1H MRS) between 3 groups indicated significant difference (P<0.05) in left frontal lobe in mI/H20 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/H2O ratio (0.55 vs. 0.51). An additional significant difference within medial temporal lobe was found between DP and AD in Glx/H2O ratio (0.44 vs. 0.34) on the right side.Conclusions1H 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.