title: Alberta Stroke Program Early CT Score Infarct Location Predicts Outcome Following M2 Occlusion.
abstract: BACKGROUND
  Although it is generally thought that patients with distal middle cerebral artery (M2) occlusion have a favorable outcome, it has previously been demonstrated that a substantial minority will have a poor outcome by 90 days. We sought to determine whether assessing the Alberta Stroke Program Early CT Score (ASPECTS) infarct location allows for identifying patients at risk for a poor 90-day outcome.
  
  
  METHODS
  We retrospectively analyzed patients with isolated acute M2 occlusion admitted to a single academic center between January 2010 and August 2012. Infarct regions were defined according to ASPECTS system on the initial head computed tomography. Discriminant function analysis was used to define specific ASPECTS regions that are predictive of the 90-day functional outcome as defined as a modified Rankin Scale score of 3-6. In addition, logistic regression was used to model the relationship between each individual ASPECT region with poor outcome; for evaluation and comparison, odds ratios,c-statistics, and Akaike information criterion values were estimated for each region.
  
  
  RESULTS
  Ninety patients with isolated M2 were included in the final analysis. ASPECTS score ≤6 predicted poor outcome in this cohort (sensitivity = 0.591, specificity = 0.838,p< 0.001). Using multiple approaches, we found that infarction in ASPECTS regions M3 and M6 were strongly associated with poor functional status by 90 days.
  
  
  CONCLUSIONS
  Infarction in ASPECTS regions M3 and M6 are key predictors of functional outcome following isolated distal M2 occlusion. These findings will be helpful in stratifying outcomes if validated in future studies.
authors.affiliation: Neuroscience Institute, Division of Neurology, Spectrum Health, Grand Rapids, MI, USA; Michigan State University College of Human Medicine, Grand Rapids, MI, USA.
authors.forename: Muhib
authors.initials: M
authors.lastname: Khan
authors.affiliation: Lifespan Biostatistics Core, Rhode Island Hospital , Providence, RI , USA.
authors.forename: Grayson L
authors.initials: GL
authors.lastname: Baird
authors.affiliation: Department of Neurology, University of Massachusetts Medical School , Worcester, MA , USA.
authors.forename: Richard P
authors.initials: RP
authors.lastname: Goddeau
authors.affiliation: Department of Neurology, Warren Alpert Medical School of Brown University , Providence, RI , USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Silver
authors.affiliation: Department of Neurology, University of Massachusetts Medical School, Worcester, MA, USA; Department of Psychiatry, University of Massachusetts Medical School, Worcester, MA, USA.
authors.forename: Nils
authors.initials: N
authors.lastname: Henninger
keywords: Alberta Stroke Program Early CT Score; M2 occlusions; outcome; stroke; thrombolysis