title: Microvessel changes after post-ischemic benign and malignant hyperemia: experimental study in rats.
abstract: BACKGROUND
  The present investigation was designed to elucidate the use of dynamic contrast enhanced perfusion MR imaging (DCE pMRI) in characterizing hyperemia, including microvessel changes, and to examine whether DCE pMRI can predict benign or malignant hyperemia.
  
  
  METHODS
  Sprague-Dawley rats underwent middle cerebral artery occlusion (MCAO) by intraluminal suture placement. All rats were randomized to 4 groups: MCAO for 0.5 hours followed by saline treatment (10 ml/kg; group 1); MCAO for 3 hours followed by treatment with saline (group 2) or urokinase (25000 IU/kg; group 3); and MCAO for 6 hours followed by urokinase treatment (group 4). Relative cerebral blood volume (rCBV) and relative maximum slope of increase of the signal intensity time curve (rMSI) were quantitatively analyzed from MRI. Microvessel diameter and blood-brain barrier disruption obtained by laser scanning confocal microscopy (LSCM) as well as transmission electron microscopy (TEM) were obtained for correlative study.
  
  
  RESULTS
  Benign hyperemia was noticed only in group 1; malignant hyperemia was seen in group 3. Although the rCBV of malignant hyperemia was slightly higher than in benign hyperemia (P > 0.05), the rMSI, on the other hand, was significantly lower (P < 0.05). Fluoro-isothiocyanate dextran (FITC-dextran) extravasations, marked glial end-foot process swelling, and significant vasodilatation were seen in malignant hyperemia, while no or mild leakage of FITC-dextran and slight glial end-foot process swelling occurred in benign hyperemia.
  
  
  CONCLUSIONS
  Our findings indicate that DCE pMRI can characterize post-ischemic hyperemia and correlates well with microvascular damage.
authors.affiliation: Department of Diagnostic and Interventinal Radiololgy, Shanghai Sixth People's Hospital, Shanghai Jiao Tong University, Shanghai, 200233, PR China.
authors.forename: Haitao
authors.initials: H
authors.lastname: Lu
authors.forename: Jungong
authors.initials: J
authors.lastname: Zhao
authors.forename: Minghua
authors.initials: M
authors.lastname: Li
authors.forename: Yingsheng
authors.initials: Y
authors.lastname: Cheng
authors.forename: Yongdong
authors.initials: Y
authors.lastname: Li
authors.forename: Xiaofang
authors.initials: X
authors.lastname: You
authors.forename: Yuwu
authors.initials: Y
authors.lastname: Zhao
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001812:Blood-Brain Barrier / Q000473:pathology / Q000648:ultrastructure; D002560:Cerebrovascular Circulation / Q000187:drug effects / Q000502:physiology*; D004195:Disease Models, Animal; D005343:Fibrinolytic Agents / Q000627:therapeutic use; D006940:Hyperemia / Q000473:pathology* / Q000503:physiopathology; D020244:Infarction, Middle Cerebral Artery / Q000188:drug therapy / Q000473:pathology* / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D018613:Microscopy, Confocal / Q000379:methods; D046529:Microscopy, Electron, Transmission / Q000379:methods; D055806:Microvessels / Q000187:drug effects / Q000473:pathology* / Q000648:ultrastructure; D051381:Rats; D015424:Reperfusion / Q000379:methods; D013997:Time Factors; D014568:Urokinase-Type Plasminogen Activator / Q000627:therapeutic use
chemical_list: D005343:Fibrinolytic Agents; D014568:Urokinase-Type Plasminogen Activator
references.citation: AJNR Am J Neuroradiol. 2004 May;25(5):746-55
references.pmid: 15140713
references.citation: J Cereb Blood Flow Metab. 1999 May;19(5):467-82
references.pmid: 10326714
references.citation: J Cereb Blood Flow Metab. 1997 Apr;17(4):388-400
references.pmid: 9143221
references.citation: Neurology. 2001 Dec 11;57(11):2015-21
references.pmid: 11739819
references.citation: J Neurosci Methods. 2006 Sep 15;155(2):285-90
references.pmid: 16513179
references.citation: J Neurosurg. 1991 Dec;75(6):845-55
references.pmid: 1941113
references.citation: Stroke. 1986 May-Jun;17(3):472-6
references.pmid: 3715945
references.citation: AJNR Am J Neuroradiol. 2003 Sep;24(8):1554-9
references.pmid: 13679270
references.citation: AJNR Am J Neuroradiol. 2004 Sep;25(8):1342-7
references.pmid: 15466329
references.citation: J Neurol Sci. 1997 Dec 9;153(1):8-11
references.pmid: 9455971
references.citation: Stroke. 2004 Nov;35(11 Suppl 1):2659-61
references.pmid: 15472105
references.citation: J Neurosci Methods. 2006 Sep 30;156(1-2):161-5
references.pmid: 16569436
references.citation: Stroke. 1998 Jan;29(1):144-51
references.pmid: 9445344
references.citation: Neurosurgery. 2005 Mar;56(3):571-81
references.pmid: 15730583
references.citation: Stroke. 2008 Feb;39(2):427-32
references.pmid: 18174480
references.citation: Acta Neurochir (Wien). 1991;109(3-4):126-32
references.pmid: 1858530
references.citation: Circulation. 2007 Mar 27;115(12):1599-608
references.pmid: 17372179
references.citation: J Cereb Blood Flow Metab. 2003 Aug;23(8):879-94
references.pmid: 12902832
references.citation: J Neurosurg. 1989 Jan;70(1):73-80
references.pmid: 2909690
references.citation: Stroke. 1996 Sep;27(9):1616-22; discussion 1623
references.pmid: 8784138