title: Magnetic Resonance Spectroscopy in Alzheimer's Disease: Systematic Review and Meta-Analysis.
abstract: BACKGROUND
  The application of non-invasive proton magnetic resonance spectroscopy (1H-MRS) could potentially identify changes in cerebral metabolites in the patients with Alzheimer's disease (AD). However, whether these metabolites can serve as biomarkers for the diagnosis of AD remains unclear.
  
  
  OBJECTIVE
  Using meta-analysis, we aimed to investigate the patterns of cerebral metabolite changes in several cerebral regions that are strongly associated with cognitive decline in AD patients.
  
  
  METHODS
  Using Hedges' g effect size, a systematic search was performed in PubMed, Cochrane Library, Ovid, Embase, and EBSCO, and 38 studies were integrated into the final meta-analysis.
  
  
  RESULTS
  According to the observational studies, N-acetyl aspartate (NAA) in AD patients was significantly reduced in the posterior cingulate (PC) (effect size (ES) =-0.924, p <  0.005) and bilateral hippocampus (left hippocampus: ES =-1.329, p <  0.005; right hippocampus: ES =-1.287, p <  0.005). NAA/Cr (creatine) ratio decreased markedly in the PC (ES =-1.052, p <  0.005). Simultaneously, significant elevated myo-inositol (mI)/Cr ratio was found not only in the PC but also in the parietal gray matter. For lack of sufficient data, we failed to elucidate the efficacy of pharmacological interventions with the metabolites changes.
  
  
  CONCLUSIONS
  The available data indicates that NAA, mI, and the NAA/Cr ratio might be potential biomarkers of brain dysfunction in AD subjects. Choline (Cho)/Cr and mI/NAA changes might also contribute toward the diagnostic process. Thus, large, well-designed studies correlated with cerebral metabolism are needed to better estimate the cerebral extent of alterations in brain metabolite levels in AD patients.
authors.affiliation: Department of Neurology, Qingdao Municipal Hospital, Dalian Medical University, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Neurology, Qingdao Municipal Hospital, Dalian Medical University, China.|Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, China.|Department of Neurology, Qingdao Municipal Hospital, Nanjing Medical University, China.
authors.forename: Lan
authors.initials: L
authors.lastname: Tan
authors.affiliation: Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, China.
authors.forename: Hui-Fu
authors.initials: HF
authors.lastname: Wang
authors.affiliation: Department of Neurology, Qingdao Municipal Hospital, Dalian Medical University, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, China.
authors.forename: Rui-Hua
authors.initials: RH
authors.lastname: Yin
authors.affiliation: Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, China.
authors.forename: Wen-Ying
authors.initials: WY
authors.lastname: Wang
authors.affiliation: Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, China.
authors.forename: Xiao-Long
authors.initials: XL
authors.lastname: Chang
authors.affiliation: Department of Neurology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China.
authors.forename: Teng
authors.initials: T
authors.lastname: Jiang
authors.affiliation: Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, China.|Department of Neurology, Qingdao Municipal Hospital, Nanjing Medical University, China.|Department of Neurology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China.|Memory and Aging Center, Deparment of Neurology, University of California, San Francisco, USA.
authors.forename: Jin-Tai
authors.initials: JT
authors.lastname: Yu
mesh_terms: D000544:Alzheimer Disease / Q000378:metabolism* / Q000473:pathology; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D001921:Brain / Q000378:metabolism*; D003401:Creatine / Q000378:metabolism; D016206:Databases, Bibliographic / Q000706:statistics & numerical data; D006801:Humans; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D011522:Protons
chemical_list: D011522:Protons; D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine
keywords: Alzheimer’s disease; N-acetyl aspartate; choline; creatine; glutamate and glutamine; magnetic resonance spectroscopy; meta-analysis; myo-inositol