title: A topographic study of the evolution of the MR DWI/PWI mismatch pattern and its clinical impact: a study by the EPITHET and DEFUSE Investigators.
abstract: OBJECTIVE
  The ischemic penumbra may be classical, with complete annular configuration around the infarct core, or nonclassical with a more fragmented pattern. We tested the hypotheses that these penumbral patterns may: be associated with specific predictive factors, influence infarct growth and clinical outcome, and influence the effect of tissue plasminogen activator (t-PA).
  
  
  METHODS
  Using the EPITHET/DEFUSE data set, in which patients received alteplase or placebo 3 to 6 hours poststroke, perfusion-weighted imaging and diffusion-weighted imaging images were analyzed. These mismatch patterns were defined as "classical" or "nonclassical." Multivariate analysis was used to identify variables associated with mismatch patterns, the effect of t-PA, as well as the relationship between mismatch patterns, infarct growth, and clinical outcomes.
  
  
  RESULTS
  We included 158 patients (median age, 74 years; median National Institute of Health Stroke Scale score, 12). Multivariate analysis indicated that the factors associated with classical mismatch pattern type were large mismatch volume (P<0.001) and cortical infarct location (P=0.036). Infarct growth, clinical outcome, and the efficacy of t-PA were not statistically different between patterns.
  
  
  CONCLUSIONS
  Coregistered mismatch volume and cortical location of infarction were the important factors associated with presence of the classical mismatch pattern. The lack of effect of the type of mismatch patterns on infarct growth, clinical outcomes, or the benefit of t-PA would suggest that mismatch topography is less important during the hyperacute phase of ischemic stroke than during subacute phase.
authors.affiliation: Florey Neuroscience Institutes, Australia.
authors.forename: Toshiyasu
authors.initials: T
authors.lastname: Ogata
authors.forename: Yoshinari
authors.initials: Y
authors.lastname: Nagakane
authors.forename: Soren
authors.initials: S
authors.lastname: Christensen
authors.forename: Henry
authors.initials: H
authors.lastname: Ma
authors.forename: Bruce C V
authors.initials: BC
authors.lastname: Campbell
authors.forename: Leonid
authors.initials: L
authors.lastname: Churilov
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Olivot
authors.forename: Patricia M
authors.initials: PM
authors.lastname: Desmond
authors.forename: Gregory W
authors.initials: GW
authors.lastname: Albers
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Davis
authors.forename: Geoffrey A
authors.initials: GA
authors.lastname: Donnan
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005343:Fibrinolytic Agents / Q000627:therapeutic use; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008875:Middle Aged; D011379:Prognosis; D020521:Stroke / Q000175:diagnosis / Q000188:drug therapy / Q000473:pathology*; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use; D016896:Treatment Outcome
chemical_list: D005343:Fibrinolytic Agents; D010959:Tissue Plasminogen Activator