title: Symptomatic carotid artery stenosis: impairment of cerebral autoregulation measured at the brain tissue level with arterial spin-labeling MR imaging.
abstract: OBJECTIVE
  To measure the cerebral autoregulatory status of the brain tissue supplied by the individual brain-feeding arteries in patients with symptomatic stenosis of the internal carotid artery (ICA) by using arterial spin-labeling (ASL) magnetic resonance (MR) imaging and to compare this status with that in healthy controls.
  
  
  METHODS
  Institutional review board approval and informed consent were obtained. Twenty-three patients (mean age, 69.3 years +/- 8.0 [standard deviation]) with unilateral symptomatic stenosis of the ICA and 20 healthy controls (mean age, 66.8 years +/- 6.3 [standard deviation]) underwent perfusion and flow territory-selective ASL MR imaging before and after intravenous administration of acetazolamide. Cerebrovascular reactivity was measured throughout the brain in the gray matter that is supplied by the individual ICAs and the basilar artery. Data were analyzed with paired and unpaired t tests.
  
  
  RESULTS
  In patients with symptomatic stenosis of the ICA, the flow territory of the symptomatic ICA was smaller than that of the asymptomatic ICA. After administration of acetazolamide, a significant increase in cerebral blood flow at the brain tissue level was measured in both control subjects and patients in all perfusion territories. Mean cerebrovascular reactivity values were 35.9% +/- 3.0% (standard error) and 44.6% +/- 3.5% (standard error) in the flow territories of the patients with symptomatic ICAs and those with asymptomatic ICAs, respectively, and 47.9% +/- 3.1% (standard error) in the control subjects. Cerebrovascular reactivity was lower in the flow territory of the symptomatic ICA than in the arteries of control participants (mean difference, -12.0%; 95% confidence interval: -20.7%, -3.3%).
  
  
  CONCLUSIONS
  In patients with symptomatic stenosis of the ICA, vasodilatory capacity in the flow territories of the major cerebral arteries can be visualized and quantified at the brain tissue level with ASL MR imaging.
authors.affiliation: Department of Radiology, University Medical Center Utrecht, HP E.01.132, Heidelberglaan 100, Utrecht, the Netherlands. r.p.h.bokkers@umcutrecht.nl
authors.forename: Reinoud P H
authors.initials: RP
authors.lastname: Bokkers
authors.forename: Matthias J P
authors.initials: MJ
authors.lastname: van Osch
authors.forename: H Bart
authors.initials: HB
authors.lastname: van der Worp
authors.forename: Gert J
authors.initials: GJ
authors.lastname: de Borst
authors.forename: Willem P T M
authors.initials: WP
authors.lastname: Mali
authors.forename: Jeroen
authors.initials: J
authors.lastname: Hendrikse
mesh_terms: D000086:Acetazolamide / Q000008:administration & dosage; D000368:Aged; D001783:Blood Flow Velocity / Q000502:physiology; D002257:Carbonic Anhydrase Inhibitors / Q000008:administration & dosage; D016893:Carotid Stenosis / Q000503:physiopathology*; D016022:Case-Control Studies; D002560:Cerebrovascular Circulation / Q000502:physiology; D002561:Cerebrovascular Disorders / Q000503:physiopathology*; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D016018:Least-Squares Analysis; D018810:Magnetic Resonance Angiography; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D013113:Spin Labels
chemical_list: D002257:Carbonic Anhydrase Inhibitors; D013113:Spin Labels; D000086:Acetazolamide