Alzheimer's disease and proton magnetic resonance spectroscopy of limbic regions: a suggestion of a clinical-spectroscopic staging.

OBJECTIVE To compare magnetic resonance proton spectroscopic with clinical data and to propose a spectroscopic staging of Alzheimer's disease (AD). METHOD Subjects (n = 46), normals (12) and with AD (34), paired to age (CDR0-CDR3); AD diagnosis according to DSM-IV/NINCDS-ADRDA criteria; 1H-MRS with Signa Horizon LX-GE, 1.5T; single voxel at hippocampal region/HCR and posterior cingulate area/PCA. RESULTS Statistically significant decrease (p < 0.01) only of Naa/Cr--at HCR among the CDR0, CDR1+CDR2, and CDR3, and at PCA between CDR0 and CDR1+CDR2 in relation to CDR3. CONCLUSION The HCR is the first to show Naa reduction (CDR1). The PCA suffers later (CDR3). These values decline progressively according to the severity stages. Considering the disparities between the HCR and PCA it is possible to suggest a spectroscopic (metabolite) staging (MS) of AD, as follows: MS0 (-CDR0) = both normal HCR and PCA, MS1-2 (approximately CDR1-2) = abnormal HCR and normal PCA, and MS3 (approximately CDR3) = both abnormal HCR and PCA. These results make possible the early diagnosis, to follow the degenerative process throughout the course, and to suggest a spectroscopic staging related to the clinical stages of AD.