Brain metabolism assessed via proton magnetic resonance spectroscopy in patients with amnestic or vascular mild cognitive impairment

- Subjects with A-MCI showed a reduced NAA/CR ratio within the hippocampus.
- Subjects with V-MCI showed a reduced NAA/CR ratio within the frontal lobe.
- A positive correlation between NAA/CR in the hippocampus and recent memory was found in A-MCI.
- The NAA/CR in the frontal lobe was positively correlated with some non-memory cognitive functions (e.g. praxis, orientation) in V-MCI.

Background and objectivesTo address the possible role of brain regional metabolic differences between different types of mild cognitive impairment (MCI).Patients and methodsBrain regional metabolites in patients with amnestic mild cognitive impairment (A-MCI) and vascular mild cognitive impairment (V-MCI) were measured via proton magnetic resonance spectroscopy (1H MRS) technique. Twenty-eight patients with A-MCI, 24 patients with V-MCI and 34 normal controls (NC) were tested by a battery of neuropsychological screens. All the subjects underwent the single voxel 1H MRS with the regions of interest (ROIs) located in the left frontal lobe, left basal ganglia and left hippocampus.ResultsThe A-MCI showed lower NAA/Cr ratio in the left hippocampus. There was a significant correlation between recent memory score and the NAA/Cr ratio. In V-MCI, NAA/Cr ratio in the left frontal lobe was positively correlated with the cognitive score evaluated with Cambridge Cognitive Examination-Chinese version (CAMCOG-C) and its subscores of orientation, praxi, language and language comprehension.ConclusionsThis study indicated that there are differences in metabolism related to brain regions between A-MCI and V-MCI, thus it may be concluded that 1H MRS may be a useful tool to differentiate A-MCI and V-MCI.