title: Ischemic brain tissue water content: CT monitoring during middle cerebral artery occlusion and reperfusion in rats.
abstract: OBJECTIVE
  To prospectively perform computed tomography (CT) in rats to determine whether ischemic edema can be reversed by using early arterial reperfusion.
  
  
  METHODS
  This study was approved by the local animal protection committee. A suture model was used to occlude the right middle cerebral artery (MCA) in rats for 1, 2, 3, or 4 hours. X-ray attenuation of the brain was measured directly before reperfusion and repeatedly during reperfusion for up to 24 hours. Infarct volumes were determined with triphenyltetrazolium chloride staining. Means of attenuation and infarct volume were compared between hemispheres and groups with a paired t test and analysis of variance. Mixed linear models were applied to compare attenuation among groups over time.
  
  
  RESULTS
  During MCA occlusion, attenuation decreased to 69.3 HU +/- 1.9 (standard deviation) after 1 hour (n=12), 66.6 HU +/- 2.0 after 2 hours (n=10), 65.4 HU +/- 2.9 after 3 hours (n=11), and 64.1 HU +/- 1.8 after 4 hours (n=9) (P<.0001). After reperfusion, attenuation remained stable in the 1-hour occlusion group (P=.16) but further and steadily declined in the 2-, 3-, and 4-hour occlusion groups (P<.001). Attenuation during reperfusion in the 1-hour occlusion group differed significantly from that in the 2-, 3-, and 4-hour occlusion groups.
  
  
  CONCLUSIONS
  CT is able to help monitor ischemic edema after MCA occlusion and reperfusion. Ischemic brain edema was not consistently reversible with reperfusion, even after 1 hour of occlusion, and further increased with reperfusion induced at 2 hours or later.
authors.affiliation: Department of Neuroradiology, Universitaetsklinikum Carl Gustav Carus, University of Dresden, Fetscherstrasse 74, D-01307 Dresden, Germany. imanuel.dzialowski@neuro.med.tu-dresden.de
authors.forename: Imanuel
authors.initials: I
authors.lastname: Dzialowski
authors.forename: Ernst
authors.initials: E
authors.lastname: Klotz
authors.forename: Sophia
authors.initials: S
authors.lastname: Goericke
authors.forename: Arnd
authors.initials: A
authors.lastname: Doerfler
authors.forename: Michael
authors.initials: M
authors.lastname: Forsting
authors.forename: Rüdiger
authors.initials: R
authors.lastname: von Kummer
mesh_terms: D000818:Animals; D001834:Body Water / Q000378:metabolism*; D002545:Brain Ischemia / Q000000981:diagnostic imaging* / Q000378:metabolism*; D020244:Infarction, Middle Cerebral Artery / Q000000981:diagnostic imaging* / Q000378:metabolism*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D015424:Reperfusion / Q000379:methods*; D015427:Reperfusion Injury / Q000000981:diagnostic imaging / Q000378:metabolism; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*