REDUCED N-ACETYLASPARTATE CONTENT IN THE FRONTAL PART OF THE BRAIN INPATIENTS WITH PROBABLE ALZHEIMERS-DISEASE

The fully relaxed water signal was used as an internal standard in a S TEAM experiment to calculate the concentrations of the metabolites: N- acetylaspartate (NAA), creatine+phosphocreatine [Cr+PCr], and choline- containing metabolites (Cho) in the frontal part of the brain in 12 pa tients with probable Alzheimer's disease, Eight age-matched healthy vo lunteers served as controls, Furthermore, T-1 and T-2 relaxation times of the metabolites and signal ratios: NAA/Cho, NAA/[Cr+PCr], and [CrPCr]/Cho at four different echo times (TE) and two different repetitio n times (TR) were calculated. The experiments were carried out using a Siemens Helicon SP 63/84 wholebody MR-scanner at 1.5 T. The concentra tion of NAA was significantly lower in the patients with probable Alzh eimer's disease than in the healthy volunteers, No significant differe nce was found for any other metabolite concentration, For the signal r atios the only statistically significant difference was that the NAA/C ho ratio at TE=92 ms and TR=1.6 s was lower in the patients with proba ble Alzheimer's disease compared with the control group. A trend towar ds a longer T-2 relaxation time for NAA in the patients with probable Alzheimer's disease than among the healthy volunteers was found, but n o significant difference was found concerning the T-1 and T-2 relaxati on times.