title: [Estimation of postmortem interval with single-voxel proton 1H-MR spectroscopy at different temperature].
abstract: OBJECTIVE
  To find an objective method for estimation of postmortem interval (PMI) with single-voxel proton MR spectroscopy at different temperature.
  
  
  METHODS
  Changes of metabolite peak area and peak area ratio of the N-acetylaspartate (Naa), choline (Cho) and total creatine (Cr) in the brain of 24 rabbit models were measured by 1H-MR spectroscopy (1H-MRS) at 0.5, 1, 2, 4, 6, 8, 12, 16 and 24 h, respectively after death.
  
  
  RESULTS
  Naa and Cr decreased continuously with the extension of PMI, and the ratios of Naa/Cr and Cho/Cr also decreased continuously with the extension of PMI within 24 h. The quadratic polynomial regression equation is y=0.0019x2-0.803x+1.4498 (R2=0.962) (Equation 1) with the Naa/Cr used as an independent variable, while the quadratic polynomial regression equation is y=-0.0024x2+0.926x+1.1777 (R2=0.986) (Equation 2) with the Cho/Cr used as an independent variable. The average deviations were about 2.10-37.90 min and 1.69-40.87 min, respectively if the PMI was estimated by Equation 1 and Equation 2, respectively.
  
  
  CONCLUSIONS
  Our study indicates that there is a strong correlation between Naa/Cr, Cho/Cr and PMI, which may be used for estimation of PMI at different temperature.
authors.affiliation: Department of Forensic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China. yttwowo@163.com
authors.forename: Tian-Tong
authors.initials: TT
authors.lastname: Yang
authors.forename: Zhen-Wei
authors.initials: ZW
authors.lastname: Li
authors.forename: Liang
authors.initials: L
authors.lastname: Liu
authors.forename: Na
authors.initials: N
authors.lastname: Zhen
mesh_terms: D000818:Animals; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000032:analysis; D001923:Brain Chemistry; D002794:Choline / Q000032:analysis; D003401:Creatine / Q000032:analysis; D049429:Forensic Pathology; D009682:Magnetic Resonance Spectroscopy; D011180:Postmortem Changes; D011817:Rabbits; D013696:Temperature; D013997:Time Factors
chemical_list: D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline