Brain changes with aging: MR spectroscopy at supraventricular plane shows differences between women and men.

PURPOSE

To assess the effect of aging on the proportions of choline (Cho), creatine, and N-acetylaspartate (NAA) in the brains of elderly women and men.

MATERIALS AND METHODS

A transverse plane above the ventricle of the brain was mapped with magnetic resonance spectroscopy. Examinations were performed in 1995-1996 with 271 healthy subjects (age range, 60-90 years; mean age, 73 years) and were repeated 4 years later (1999-2000). Student t tests were used for statistical analysis.

RESULTS

Difference analysis of the changes in 4 years (paired data) reproduced the decrease in Cho in women only (2.9% per year, P <.001) that had been indicated with intersubject correlation analyses. Decreases in NAA, though significant in both men and women according to age correlation analyses (P <.01 for both), did not reach significance. The resulting sex difference in the Cho/NAA ratio at a mean age of 77 years, while not yet significant at a mean age of 73 years, was especially manifest in the posterior half of the plane analyzed.

CONCLUSION

Increasing sex differences in Cho/NAA ratios in a supraventricular plane indicate that brain metabolite levels differ between women and men at advanced age.