title: Proton magnetic resonance spectroscopy reveals significant decline in the contents ofN-acetylaspartylglutamate in the hippocampus of aged healthy subjects.
abstract: BACKGROUND
  To characterize the contents of choline (Cho), creatine (Cr) and N-acetylaspartylglutamate (NAA) in the hippocampus of healthy volunteers, we investigated the contents and their correlationship with age, gender and laterality.
  
  
  METHODS
  Volunteers were grouped into a young, a middle and an old age. The Cho, Cr and NAA contents were determined with proton magnetic resonance spectroscopy (1H-MRS), and the correlationship was analyzed with Pearson correlation.
  
  
  RESULTS
  The concentration of NAA in the bilateral hippocampi was markedly lower in the old than in the young and the middle (LSD test, allp< 0.025). Furthermore, NAA/Cr in the bilateral hippocampi head (left: 1.10 ±0.40 vs. 1.54 ±0.49 or 1.43 ±0.49; right: 1.04 ±0.42 vs. 1.35 ±0.40 or 1.30 ±0.42), region 1 of the bilateral hippocampal body (left: 1.24 ±0.53 vs. 1.58 ±0.58 or 1.35 ±0.44; right: 1.30 ±0.43 vs. 1.54 ±0.51 or 1.35 ±0.51) and region 2 of the left hippocampal body (1.21 ±0.32 vs. 1.46 ±0.36 or 1.36 ±0.44) and the left hippocampal tail (1.11 ±0.40 vs. 1.36 ±0.47 or 1.15 ±0.32) was significantly higher in the old than in the young and the middle, respectively (allp< 0.026). The NAA content in the bilateral hippocampal head, body and tail negatively correlated with age. Moreover, the NAA, Cho and Cr contents in the hippocampal body and the tail were higher in the right than the left.
  
  
  CONCLUSIONS
  The NAA content of the hippocampal head, body and tail were significantly decreased in the old compared with younger persons, and it negatively correlates with age. The NAA, Cho and Cr contents exhibit laterality in the hippocampal body and tail.
authors.affiliation: Department of Radiology, the Second Hospital of Hebei Medical University, Shijiazhuang, China.
authors.forename: Ruiting
authors.initials: R
authors.lastname: Chang
authors.affiliation: Department of Radiology, the Second Hospital of Hebei Medical University, Shijiazhuang, China.
authors.forename: Zuojun
authors.initials: Z
authors.lastname: Geng
authors.affiliation: Department of Radiology, the Second Hospital of Hebei Medical University, Shijiazhuang, China.
authors.forename: Qingfeng
authors.initials: Q
authors.lastname: Zhu
authors.affiliation: Department of Radiology, the Second Hospital of Hebei Medical University, Shijiazhuang, China.
authors.forename: Zhenhu
authors.initials: Z
authors.lastname: Song
authors.affiliation: Department of Radiology, the Second Hospital of Hebei Medical University, Shijiazhuang, China.
authors.forename: Ya
authors.initials: Y
authors.lastname: Wang
keywords: N-acetylaspartylglutamate; aging; choline; hippocampus; proton magnetic resonance spectroscopy