title: Magnetic resonance imaging of regional hemodynamic and cerebrovascular recovery after lateral fluid-percussion brain injury in rats.
abstract: Hemodynamic and cerebrovascular factors are crucially involved in secondary damage after traumatic brain injury (TBI). With magnetic resonance imaging, this study aimed to quantify regional cerebral blood flow (CBF) by arterial spin labeling and cerebral blood volume by using an intravascular contrast agent, during 14 days after lateral fluid-percussion injury (LFPI) in rats. Immunohistochemical analysis of vessel density was used to evaluate the contribution of vascular damage. Results show widespread ipsilateral and contralateral hypoperfusion, including both the cortex and the hippocampus bilaterally, as well as the ipsilateral thalamus. Hemodynamic unrest may partly be explained by an increase in blood vessel density over a period of 2 weeks in the ipsilateral hippocampus and perilesional cortex. Furthermore, three phases of perilesional alterations in CBF, progressing from hypoperfusion to normal and back to hypoperfusion within 2 weeks were shown for the first time in a rat TBI model. These three phases were similar to hemodynamic fluctuations reported in TBI patients. This makes it feasible to use LFPI in rats to study mechanisms behind hemodynamic changes and to explore novel therapeutic approaches for secondary brain damage after TBI.
authors.affiliation: Biomedical Imaging Unit, Department of Neurobiology, A I Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland.
authors.forename: Nick Mark Edward Alexander
authors.initials: NM
authors.lastname: Hayward
authors.forename: Pasi I
authors.initials: PI
authors.lastname: Tuunanen
authors.forename: Riikka
authors.initials: R
authors.lastname: Immonen
authors.forename: Xavier Ekolle
authors.initials: XE
authors.lastname: Ndode-Ekane
authors.forename: Asla
authors.initials: A
authors.lastname: Pitkänen
authors.forename: Olli
authors.initials: O
authors.lastname: Gröhn
mesh_terms: D000818:Animals; D001784:Blood Gas Analysis; D001808:Blood Vessels / Q000473:pathology; D001810:Blood Volume / Q000502:physiology; D001930:Brain Injuries / Q000401:mortality / Q000473:pathology / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D007839:Functional Laterality / Q000502:physiology; D006439:Hemodynamics / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D008279:Magnetic Resonance Imaging; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D016707:Tissue Fixation