title: Extent of hypoattenuation on CT angiography source images predicts functional outcome in patients with basilar artery occlusion.
abstract: OBJECTIVE
  Quantification of early ischemic changes (EIC) may predict functional outcome in patients with basilar artery occlusion (BAO). We tested the validity of a novel CT score, the posterior circulation Acute Stroke Prognosis Early CT score (pc-ASPECTS).
  
  
  METHODS
  Pc-ASPECTS allots the posterior circulation 10 points. Two points each are subtracted for EIC in midbrain or pons and 1 point each for EIC in left or right thalamus, cerebellum or PCA-territory, respectively. We studied 2 different populations: (1) patients with suspected vertebrobasilar ischemia and (2) patients with BAO. We applied pc-ASPECTS to noncontrast CT (NCCT), CT angiography source images (CTASI), and follow-up image by 3-reader consensus. We calculated sensitivity for ischemic changes and analyzed the predictivity of pc-ASPECTS for independent (modified Rankin Scale [mRS] score </=2) and favorable (mRS score </=3) outcome.
  
  
  RESULTS
  Of 130 patients with suspected vertebrobasilar ischemia, 72% (94) had posterior circulation stroke, 8% (10) transient ischemic attack, and 20% (26) nonischemic etiology. Sensitivity for ischemic changes was improved with CTASI compared to NCCT (65% [95% CI, 57% to 73%] versus 46% [95% CI, 37% to 55%], respectively). Pc-ASPECTS score on CTASI but not NCCT predicted functional independence (OR 1.58; P=0.005 versus 1.22; P=0.42, respectively). Of 46 patients with BAO, 52% (12/23) with CTASI pc-ASPECTS score >/=8 but only 4% (1/23) with a score <8 had favorable functional outcome (RR 12.1; 95% CI, 1.7 to 84.9). This difference was consistent in 21 patients with angiographic recanalization (RR 7.7; 95% CI, 1.1 to 52.1).
  
  
  CONCLUSIONS
  The CTASI pc-ASPECTS score may identify BAO patients unlikely to have a favorable outcome despite recanalization.
authors.affiliation: University of Technology Dresden, Department of Neurology, Dresden University Stroke Center, Fetscherstrasse 74, 01307 Dresden, Germany. volker.puetz@neuro.med.tu-dresden.de
authors.forename: Volker
authors.initials: V
authors.lastname: Puetz
authors.forename: P N
authors.initials: PN
authors.lastname: Sylaja
authors.forename: Shelagh B
authors.initials: SB
authors.lastname: Coutts
authors.forename: Michael D
authors.initials: MD
authors.lastname: Hill
authors.forename: Imanuel
authors.initials: I
authors.lastname: Dzialowski
authors.forename: Pia
authors.initials: P
authors.lastname: Mueller
authors.forename: Ulf
authors.initials: U
authors.lastname: Becker
authors.forename: Gabriele
authors.initials: G
authors.lastname: Urban
authors.forename: Christine
authors.initials: C
authors.lastname: O'Reilly
authors.forename: Philip A
authors.initials: PA
authors.lastname: Barber
authors.forename: Pranshu
authors.initials: P
authors.lastname: Sharma
authors.forename: Mayank
authors.initials: M
authors.lastname: Goyal
authors.forename: Georg
authors.initials: G
authors.lastname: Gahn
authors.forename: Ruediger
authors.initials: R
authors.lastname: von Kummer
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Demchuk
mesh_terms: D000368:Aged; D000792:Angiography; D001488:Basilar Artery / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000503:physiopathology; D001933:Brain Stem / Q000098:blood supply / Q000000981:diagnostic imaging / Q000473:pathology; D002531:Cerebellum / Q000098:blood supply / Q000000981:diagnostic imaging / Q000473:pathology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care / Q000379:methods; D011237:Predictive Value of Tests; D011379:Prognosis; D020127:Recovery of Function / Q000502:physiology; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D014715:Vertebrobasilar Insufficiency / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000503:physiopathology