title: Assessing reperfusion with whole-brain arterial spin labeling: a noninvasive alternative to gadolinium.
abstract: OBJECTIVE
  Arterial spin labeling (ASL) is a perfusion imaging technique that does not require gadolinium. The study aimed to assess the reliability of ASL for evaluating reperfusion in acute ischemic stroke in comparison with dynamic susceptibility contrast (DSC) imaging.
  
  
  METHODS
  The study included 24 patients with acute ischemic stroke on admission and 24-hour follow-up ASL and DSC scans. Two readers rated images for interpretability and evidence of reperfusion. Cohen unweighted κ was used to assess (1) inter-rater reliability between readers for determining interpretability and the presence of reperfusion, (2) agreement between ASL and DSC for determining reperfusion for individual raters, and (3) agreement between ASL and DSC for determining reperfusion after consensus.
  
  
  RESULTS
  Inter-rater reliability for both ASL and DSC was moderate to good (κ of 0.67 versus 0.55, respectively). Reader 1 rated 16 patients as having interpretable ASL and DSC when compared with 15 patients for reader 2. The κ between ASL and DSC for determining reperfusion was 0.50 for reader 1 and 0.595 for reader 2. After consensus, 18 ASL and 17 DSC image sets were rated interpretable for reperfusion and 13 had both interpretable ASL and DSC scans, yielding a κ for assessment of reperfusion of 0.8.
  
  
  CONCLUSIONS
  Inter-rater reliability of ASL and DSC was moderate to good. Agreement between ASL and DSC for determining reperfusion was moderate for each individual rater and increased substantially after consensus. ASL is a noninvasive and practical alternative to DSC for reperfusion assessments in patients with confirmed acute ischemic stroke.
authors.affiliation: From the Section on Stroke Diagnostics and Therapeutics, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD (R.V.M., D.A.H., J.G.M., M.L., S.W., L.L.L.); Department of Neurobiology, Care Sciences and Society, Division of Neurodegeneration, The Karolinska Institute, Stockholm, Sweden (R.V.M.); Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands (R.P.H.B.); Department of Radiology, Gelre Hospitals, Apeldoorn, The Netherlands (R.P.H.B.); Research Scholars Program, Howard Hughes Medical Institute, Bethesda, MD (R.V.M.); Department of Neurology and Neurotherapeutics, Seton/UT Southwestern Clinical Research Institute of Austin, UT Southwestern Medical Center, TX (S.W.); and Johns Hopkins Community Physicians, Bethesda, MD (J.G.M.).
authors.forename: Raymond V
authors.initials: RV
authors.lastname: Mirasol
authors.forename: Reinoud P H
authors.initials: RP
authors.lastname: Bokkers
authors.forename: Daymara A
authors.initials: DA
authors.lastname: Hernandez
authors.forename: José G
authors.initials: JG
authors.lastname: Merino
authors.forename: Marie
authors.initials: M
authors.lastname: Luby
authors.forename: Steven
authors.initials: S
authors.lastname: Warach
authors.forename: Lawrence L
authors.initials: LL
authors.lastname: Latour
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000000981:diagnostic imaging*; D002536:Cerebral Arteries / Q000000981:diagnostic imaging*; D003287:Contrast Media; D003627:Data Interpretation, Statistical; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D005682:Gadolinium; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011446:Prospective Studies; D011859:Radiography; D015424:Reperfusion / Q000379:methods*; D015203:Reproducibility of Results; D013113:Spin Labels; D020521:Stroke / Q000000981:diagnostic imaging*
chemical_list: D003287:Contrast Media; D013113:Spin Labels; D005682:Gadolinium
keywords: magnetic resonance imaging; perfusion imaging