title: An experimental study on acute brain radiation injury: dynamic changes in proton magnetic resonance spectroscopy and the correlation with histopathology.
abstract: OBJECTIVE
  To investigate the correlation between the alterations of single-voxel (1)H MRS and the histopathological characteristics of radiation brain injury following radiation.
  
  
  METHODS
  Twenty-seven rabbits were randomized into nine groups to receive radiation with a single dose of 25 Gy. The observation time points included a pre-radiation and 1, 2, 3, 4, 5, 6, 7, and 8 wk following radiation. Each treatment group underwent conventional MRI and single-voxel 1H MRS, N-acetyl aspartate (NAA), choline (Cho), and creatine (Cr) were observed over the region of interest, and the presence or absence of lactate (Lac) and lipid (Lip) was detected. Histological specimens of each group were obtained after image acquisition.
  
  
  RESULTS
  The values of Cho were significantly increased in the first 3 wk, and decreased over the following 5 wk after radiation. Levels of NAA showed a trend toward a decrease 5 wk after radiation. The levels of Cr were not changed between before and after radiation. The Cho/NAA metabolic ratio was significantly increased in weeks 6, 7, and 8 following irradiation, compared to pre-radiation values. Vascular and glial injury appeared on 2 wk after RT in the histology samples, until 4 wk after RT, necrosis of the oligodendrocytes, neuronal degeneration and demyelination could be observed.
  
  
  CONCLUSIONS
  MRS is sensitive to detect metabolic changes following radiation, and can be used in the early diagnosis of radiation brain injury.
authors.affiliation: State Key Laboratory of Oncology in Southern China, Guangzhou, People's Republic of China. lihui@sysucc.org.cn
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.forename: Jian-peng
authors.initials: JP
authors.lastname: Li
authors.forename: Cheng-guang
authors.initials: CG
authors.lastname: Lin
authors.forename: Xue-wen
authors.initials: XW
authors.lastname: Liu
authors.forename: Zhi-jun
authors.initials: ZJ
authors.lastname: Geng
authors.forename: Yun-xian
authors.initials: YX
authors.lastname: Mo
authors.forename: Rong
authors.initials: R
authors.lastname: Zhang
authors.forename: Chuan-miao
authors.initials: CM
authors.lastname: Xie
mesh_terms: D000818:Animals; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000032:analysis; D001930:Brain Injuries / Q000378:metabolism*; D002794:Choline / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D011522:Protons; D011817:Rabbits; D011833:Radiation Injuries, Experimental / Q000378:metabolism*; D013223:Statistics as Topic
chemical_list: D011522:Protons; D001224:Aspartic Acid; C000179:N-acetylaspartate; D002794:Choline