title: Interobserver variation of ASPECTS in real time.
abstract: BACKGROUND
  The Alberta Stroke Program Early CT Score (ASPECTS) has been used to quantify early ischemic changes on computed tomography (CT) brain scans of acute stroke patients. We sought to assess the reliability of the score when performed in real time as compared with an expert rating performed at a later time point.
  
  
  METHODS
  Two hundred fourteen patients presenting with acute ischemic stroke or transient ischemic attack were prospectively recruited if they had a brain CT scan performed within 12 hours of symptom onset. Each scan was read for ASPECTS prospectively by the treating physician and later by 1 expert reader. A weighted kappa statistic was used to determine the interobserver agreement.
  
  
  RESULTS
  The median baseline National Institutes of Health Stroke Scale score was 5 (range: 0 to 32) and the median time to CT scan was 152 minutes (range: 22 to 769). The interobserver agreement between ASPECTS performed in real time and expert ASPECTS was substantial (kappa(w)=0.69). The mean difference between real-time ASPECTS and expert ASPECTS was 0 (SD: 1.1).
  
  
  CONCLUSIONS
  ASPECTS is a reliable clinical scale for rating early ischemic changes on CT when performed in real time.
authors.affiliation: Seaman Family MR Centre, Calgary Health Region, Foothills Hospital, Calgary, Alberta, Canada. shelagh.coutts@calgaryhealthregion.ca
authors.forename: Shelagh B
authors.initials: SB
authors.lastname: Coutts
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Demchuk
authors.forename: Philip A
authors.initials: PA
authors.lastname: Barber
authors.forename: William Y
authors.initials: WY
authors.lastname: Hu
authors.forename: Jessica E
authors.initials: JE
authors.lastname: Simon
authors.forename: Alastair M
authors.initials: AM
authors.lastname: Buchan
authors.forename: Michael D
authors.initials: MD
authors.lastname: Hill
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000175:diagnosis / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000175:diagnosis / Q000000981:diagnostic imaging; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011446:Prospective Studies; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D020521:Stroke / Q000175:diagnosis / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*