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

The fully relaxed water signal was used as an internal standard in a STEAM 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 patients with probable Alzheimer's disease, Eight age-matched healthy volunteers served as controls, Furthermore, T-1 and T-2 relaxation times of the metabolites and signal ratios: NAA/Cho, NAA/[Cr+PCr], and [Cr+PCr]/Cho at four different echo times (TE) and two different repetition times (TR) were calculated. The experiments were carried out using a Siemens Helicon SP 63/84 wholebody MR-scanner at 1.5 T. The concentration of NAA was significantly lower in the patients with probable Alzheimer's disease than in the healthy volunteers, No significant difference was found for any other metabolite concentration, For the signal ratios the only statistically significant difference was that the NAA/Cho ratio at TE=92 ms and TR=1.6 s was lower in the patients with probable Alzheimer's disease compared with the control group. A trend towards a longer T-2 relaxation time for NAA in the patients with probable Alzheimer's disease than among the healthy volunteers was found, but no significant difference was found concerning the T-1 and T-2 relaxation times.