title: Dual-phase CT collateral score: a predictor of clinical outcome in patients with acute ischemic stroke.
abstract: OBJECTIVE
  The presence of good collaterals on CT angiography (CTA) is a well-known predictor for favorable outcome in acute ischemic stroke. Recently, multiphase CT has been introduced as a more accurate method in assessing collaterals. The aim of this study was to assess the ability of dual-phase CT to evaluate collateral status and predict clinical outcome.
  
  
  METHODS
  Forty-three patients who underwent both dual-phase CT and transfemoral cerebral angiography (TFCA) for occluded intracranial internal carotid artery (ICA) and/or middle cerebral artery (M1 segment) were recruited from a prospectively collected database. The collateral status on dual-phase CT was graded by using a 4-point scale: grade 0 = no collaterals; 1 = some collaterals with persistence of some defects; 2 = slow but complete collaterals; and 3 = fast and complete collaterals. Univariate and multivariate analysis were performed to define the independent predictors for favorable outcome at 3 months.
  
  
  RESULTS
  Dual-phase CT collateral status (ρ = 0.744) showed higher correlation with TFCA collateral status than CTA collateral status (ρ = 0.596) and substantial interobserver agreement (weighted κ = 0.776). In the univariate analysis, age, history of hypertension, collateral scores on CTA, dual-phase CT, and TFCA, occlusion in intracranial ICA, final infarct volume, and symptomatic hemorrhage were significantly associated with outcome. Among them, only the dual-phase CT collateral score was an independent predictor for favorable outcome (OR = 26.342 (2.788-248.864); P = 0.004) in the multivariate analysis.
  
  
  CONCLUSIONS
  The collateral status on dual-phase CT can be a useful predictor for clinical outcome in acute stroke patients, especially when advanced CT techniques are not available in emergent situations.
authors.affiliation: Department of Radiology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Na-Young
authors.initials: NY
authors.lastname: Shin
authors.affiliation: Department of Radiology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Kyung-eun
authors.initials: KE
authors.lastname: Kim
authors.affiliation: Department of Radiology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Mina
authors.initials: M
authors.lastname: Park
authors.affiliation: Department of Neurology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Young Dae
authors.initials: YD
authors.lastname: Kim
authors.affiliation: Department of Radiology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Dong Joon
authors.initials: DJ
authors.lastname: Kim
authors.affiliation: Department of Radiology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Sung Jun
authors.initials: SJ
authors.lastname: Ahn
authors.affiliation: Department of Neurology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Ji Hoe
authors.initials: JH
authors.lastname: Heo
authors.affiliation: Department of Radiology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Seung-Koo
authors.initials: SK
authors.lastname: Lee
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D020520:Brain Infarction / Q000000981:diagnostic imaging*; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging; D002533:Cerebral Angiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging; D011379:Prognosis; D012189:Retrospective Studies; D012720:Severity of Illness Index; D020521:Stroke / Q000000981:diagnostic imaging* / Q000628:therapy; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome