Correlations between [18F]FDG-PET and Naa/mI spectroscopy data of the posterior cingulate cortex in amnestic mild cognitive impairment and Alzheimer's disease.

1824 Objectives To access possible differences of the findings in [18F]FDG-PET and the NAA/mI ratio in the Posterior Cingulate Cortex (PCC) while evaluating subjects with AD, MCI and cognitively normal volunteers, and also to evaluate possible correlations between both methods in the PCC of these subjects. Methods Subjects with the clinical diagnosis of AD (N = 32), MCI (N = 27) and cognitively normal older subjects (CG, N = 28), were submitted to [18F]FDG-PET and MRS examinations. SVC analysis of the PCC with PET data and evaluation of the Naa/mI ratio in the PCC with MRS in were performed. Values of the different analyses were compared across groups. We also investigated possible correlations between the data of the different modalities. Results AD group presented with decreased rBGM in large areas of the PCC and temporoparietal cortex when compared to CG (p Conclusions rBGM and Naa/mI ratio in the PCC are positively correlated, showing that neuronal injury and hypometabolism in the PCC are closely related in the biologic processes of MCI and AD. Both methods were capable of discriminating AD from cognitively normal older subjects. [18F]FDG-PET presented a higher diagnostic performance than Naa/mI.