Magnetic resonance spectroscopy evaluation of metabolism alterations within hippocampi in patients with mild cognitive impairment

The differences of between mild cognitive impairment (MCI) and normal control group (NC) of N-acetylaspartate (NAA), creatine (Cr), choline (Cho) and the metabolism ratios in hippocampus were investigated. Thirty healthy control subjects (16 males and 14 females) and thirty patients (20 males and 10 females) with MCI were recruited from the local area. Conventional magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) were performed in all subjects. NAA/(Cr+Cho) ratios on both sides of the hippocampus were calculated automatically. Relative concentrations of NAA, Cho and Cr in the hippocampus were estimated from their peak area. Relative concentrations of NAA, Cho and Cr were estimated from their peak area. A slight atrophy of hippocampus with leukoaraiosis and vacuolation were found in MCI. Hippocampus atrophy was found in 19 subjects with MCI. There were no significant differences in metabolite concentrations and ratios between right and left side of hippocampus (P>0.05). The differences between MCI and control group in relative concentrations of NAA, Cho and Cr were not significant (P>0.05). The same situations were found in the analyzing of NAA/(Cr+Cho) ratios. However, there was a trend that the means of NAA and NAA/(Cr+Cho) ratios of MCI were higher than those of NC. Although MRS may fail to individually distinguish subjects with MCI and NC, It was still a useful modality to hinder that the metabolisms changes in early MCI.