title: Traumatic Brain Injury by a Closed Head Injury Device Induces Cerebral Blood Flow Changes and Microhemorrhages.
abstract: OBJECTIVE
  Traumatic brain injury is a poly-pathology characterized by changes in the cerebral blood flow, inflammation, diffuse axonal, cellular, and vascular injuries. However, studies related to understanding the temporal changes in the cerebral blood flow following traumatic brain injury extending to sub-acute periods are limited. In addition, knowledge related to microhemorrhages, such as their detection, localization, and temporal progression, is important in the evaluation of traumatic brain injury.
  
  
  METHODS
  Cerebral blood flow changes and microhemorrhages in male Sprague Dawley rats at 4 h, 24 h, 3 days, and 7 days were assessed following a closed head injury induced by the Marmarou impact acceleration device (2 m height, 450 g brass weight). Cerebral blood flow was measured by arterial spin labeling. Microhemorrhages were assessed by susceptibility-weighted imaging and Prussian blue histology.
  
  
  RESULTS
  Traumatic brain injury rats showed reduced regional and global cerebral blood flow at 4 h and 7 days post-injury. Injured rats showed hemorrhagic lesions in the cortex, corpus callosum, hippocampus, and brainstem in susceptibility-weighted imaging. Injured rats also showed Prussian blue reaction products in both the white and gray matter regions up to 7 days after the injury. These lesions were observed in various areas of the cortex, corpus callosum, hippocampus, thalamus, and midbrain.
  
  
  CONCLUSIONS
  These results suggest that changes in cerebral blood flow and hemorrhagic lesions can persist for sub-acute periods after the initial traumatic insult in an animal model. In addition, microhemorrhages otherwise not seen by susceptibility-weighted imaging are present in diverse regions of the brain. The combination of altered cerebral blood flow and microhemorrhages can potentially be a source of secondary injury changes following traumatic brain injury and may need to be taken into consideration in the long-term care of these cases.
authors.affiliation: Department of Biomedical Engineering, Wayne State University, Detroit, Michigan, USA.
authors.forename: Srinivasu
authors.initials: S
authors.lastname: Kallakuri
authors.affiliation: Department of Biomedical Engineering, Wayne State University, Detroit, Michigan, USA.
authors.forename: Sharath
authors.initials: S
authors.lastname: Bandaru
authors.affiliation: Department of Biomedical Engineering, Wayne State University, Detroit, Michigan, USA.
authors.forename: Nisrine
authors.initials: N
authors.lastname: Zakaria
authors.affiliation: Department of Radiology, Wayne State University School of Medicine, Detroit, Michigan, USA.
authors.forename: Yimin
authors.initials: Y
authors.lastname: Shen
authors.affiliation: Department of Biomedical Engineering, Wayne State University, Detroit, Michigan, USA ; Department of Radiology, Wayne State University School of Medicine, Detroit, Michigan, USA.
authors.forename: Zhifeng
authors.initials: Z
authors.lastname: Kou
authors.affiliation: Department of Biomedical Engineering, Wayne State University, Detroit, Michigan, USA.
authors.forename: Liying
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Biomedical Engineering, Wayne State University, Detroit, Michigan, USA ; Department of Radiology, Wayne State University School of Medicine, Detroit, Michigan, USA.
authors.forename: Ewart Mark
authors.initials: EM
authors.lastname: Haacke
authors.affiliation: Department of Biomedical Engineering, Wayne State University, Detroit, Michigan, USA.
authors.forename: John M
authors.initials: JM
authors.lastname: Cavanaugh
keywords: Arterial spin labeling; Prussian blue; cerebral blood flow; hemorrhages; marmarou model; susceptibility-weighted imaging; traumatic brain injury