title: Accuracy of the Alberta Stroke Program Early CT Score during the first 3 hours of middle cerebral artery stroke: comparison of noncontrast CT, CT angiography source images, and CT perfusion.
abstract: OBJECTIVE
  The Alberta Stroke Program Early CT Score (ASPECTS) is a reliable method of delineating the extent of middle cerebral artery (MCA) stroke. Our aim was to retrospectively compare the accuracy of ASPECTS on noncontrast CT, CT angiography (CTA) source images, and CT perfusion maps of cerebral blood volume (CBV) during the first 3 hours of middle cerebral artery (MCA) stroke.
  
  
  METHODS
  First-time patients with MCA stroke who presented <3 hours from symptom onset and were evaluated by noncontrast CT/CTA/CT perfusion, had confirmed acute nonlacunar MCA infarct on diffusion-weighted MR imaging (DWI) within 7 days, and had follow-up angiography were included. Patients were excluded for persistent MCA occlusion or stenosis. Two raters through consensus assigned an ASPECTS on the noncontrast CT, CTA source images, and the section-selective (2 x 12 mm coverage) CT perfusion CBV maps. ASPECTS on follow-up DWI served as the reference standard. For each CT technique, the detection rates of regional infarction, the mean ASPECTS, and the linear correlation to final ASPECTS were determined and compared. P values <.05 were considered significant.
  
  
  RESULTS
  Twenty-eight patients satisfied the criteria with DWI performed at a mean of 50.3 hours (range, 22-125 hours) post-CT imaging. Of 280 ASPECTS regions, 100 were infarcted on DWI. The accuracy of noncontrast CT, CTA source images, and CT perfusion CBV for detecting regional infarct was 80.0%, 84.3%, and 96.8%, respectively (P < .0001). The mean ASPECTSs of noncontrast CT, CTA source images, CT perfusion CBV, and DWI were 8.4 +/- 1.8, 8.0 +/- 1.8, 6.8 +/- 1.9, and 6.5 +/- 1.8, respectively. The mean noncontrast CT and CTA source image ASPECTS was different from that of DWI (P < .05). Correlation of noncontrast CT, CTA source images, and CT perfusion CBV ASPECTS with final ASPECTS was r(2) = 0.34, r(2) = 0.42, and r(2) = 0.91, respectively.
  
  
  CONCLUSIONS
  In a retrospective cohort of MCA infarcts imaged <3 hours from stroke onset, ASPECTS was most accurately determined on CT perfusion CBV maps.
authors.affiliation: Department of Radiology, New York University Medical Center, New York, NY, USA. kelinmd@gmail.com
authors.forename: K
authors.initials: K
authors.lastname: Lin
authors.forename: O
authors.initials: O
authors.lastname: Rapalino
authors.forename: M
authors.initials: M
authors.lastname: Law
authors.forename: J S
authors.initials: JS
authors.lastname: Babb
authors.forename: K A
authors.initials: KA
authors.lastname: Siller
authors.forename: B K
authors.initials: BK
authors.lastname: Pramanik
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000416:Alberta; D002533:Cerebral Angiography / Q000379:methods*; D003287:Contrast Media; D005260:Female; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media