title: Quantification of MRI and MRS characteristics changes in a rat model at different stage of cerebral ischemia.
abstract: BACKGROUND
  A better understanding the mechanisms of cerebral ischemia is important both for diagnosis and treatment.
  
  
  OBJECTIVE
  The study aimed to quantify several characteristics of magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) to indicate the brain tissue changes at different stage of cerebral ischemia in rats.
  
  
  METHODS
  In the present study, a rat model of cerebral ischemia was established by middle cerebral artery occlusion (MCAO) in the left hemisphere. MRI and MRS were performed on 15 Sprague Dawley rats 4 H, 24 H, and 1 W after MCAO. Apparent diffusion coefficient (ADC), relative ADC including FNR, PNR, PNF, and metabolite ratio NCC were proposed to reflect the changes of water diffusion and metabolism in brain tissue.
  
  
  RESULTS
  ADCs of focal zone and penumbra zone from 1 W group were significantly larger than those from 4H group, respectively (both p < 0.05). PNR and PNF of 24H and 1 W groups were significantly less than 4H group (all p < 0.01). NCCs of focal zone and penumbra zone were significantly less than the normal zone within 4H, 24H, and 1 W groups, respectively (both p < 0.01). While NCCs of penumbra zone from 24H and 1 W groups were significantly larger than 4H group (both p < 0.01).
  
  
  CONCLUSIONS
  We conclude that combination of MRI and MRS characteristics can provide significant indicators for ischemic damage at different stage of cerebral ischemia in a rat model.
authors.affiliation: a College of Life Science and Bioengineering , Beijing University of Technology , Beijing , China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: a College of Life Science and Bioengineering , Beijing University of Technology , Beijing , China.
authors.forename: Dongmei
authors.initials: D
authors.lastname: Hao
authors.affiliation: a College of Life Science and Bioengineering , Beijing University of Technology , Beijing , China.
authors.forename: Xiuhua
authors.initials: X
authors.lastname: Lv
authors.affiliation: b Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical University , Beijing , China.
authors.forename: Shaowu
authors.initials: S
authors.lastname: Li
authors.affiliation: c State Intellectual Property Office of the P.R.C , Beijing , China.
authors.forename: Yunqing
authors.initials: Y
authors.lastname: Tian
authors.affiliation: d Faculty of Medical Science, Health and Wellbeing Academy , Anglia Ruskin University , Chelmsford , UK.
authors.forename: Dingchang
authors.initials: D
authors.lastname: Zheng
authors.affiliation: b Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical University , Beijing , China.
authors.forename: Yanjun
authors.initials: Y
authors.lastname: Zeng
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002545:Brain Ischemia / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D001931:Brain Mapping; D004195:Disease Models, Animal; D018450:Disease Progression; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley
keywords: Cerebral ischemia; Magnetic resonance imaging (MRI); Magnetic resonance spectroscopy (MRS); Middle cerebral artery occlusion (MCAO); Rat