title: Reperfusion is a more accurate predictor of follow-up infarct volume than recanalization: a proof of concept using CT in acute ischemic stroke patients.
abstract: OBJECTIVE
  The purpose of this study was to compare recanalization and reperfusion in terms of their predictive value for imaging outcomes (follow-up infarct volume, infarct growth, salvaged penumbra) and clinical outcome in acute ischemic stroke patients.
  
  
  METHODS
  Twenty-two patients admitted within 6 hours of stroke onset were retrospectively included in this study. These patients underwent a first stroke CT protocol including CT-angiography (CTA) and perfusion-CT (PCT) on admission, and similar imaging after treatment, typically around 24 hours, to assess recanalization and reperfusion. Recanalization was assessed by comparing arterial patency on admission and posttreatment CTAs; reperfusion, by comparing the volumes of CBV, CBF, and MTT abnormality on admission and posttreatment PCTs. Collateral flow was graded on the admission CTA. Follow-up infarct volume was measured on the discharge noncontrast CT. The groups of patients with reperfusion, no reperfusion, recanalization, and no recanalization were compared in terms of imaging and clinical outcomes.
  
  
  RESULTS
  Reperfusion (using an MTT reperfusion index >75%) was a more accurate predictor of follow-up infarct volume than recanalization. Collateral flow and recanalization were not accurate predictors of follow-up infarct volume. An interaction term was found between reperfusion and the volume of the admission penumbra >50 mL.
  
  
  CONCLUSIONS
  Our study provides evidence that reperfusion is a more accurate predictor of follow-up infarct volume in acute ischemic stroke patients than recanalization. We recommend an MTT reperfusion index >75% to assess therapy efficacy in future acute ischemic stroke trials that use perfusion-CT.
authors.affiliation: Department of Radiology, Neuroradiology Section, University of California, San Francisco, 505 Parnassus Avenue, Box 0628, San Francisco, CA 94143-0628, USA.
authors.forename: Bruno P
authors.initials: BP
authors.lastname: Soares
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Tong
authors.forename: Jason
authors.initials: J
authors.lastname: Hom
authors.forename: Su-Chun
authors.initials: SC
authors.lastname: Cheng
authors.forename: Joerg
authors.initials: J
authors.lastname: Bredno
authors.forename: Loic
authors.initials: L
authors.lastname: Boussel
authors.forename: Wade S
authors.initials: WS
authors.lastname: Smith
authors.forename: Max
authors.initials: M
authors.lastname: Wintermark
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000000981:diagnostic imaging / Q000503:physiopathology; D002544:Cerebral Infarction / Q000000981:diagnostic imaging* / Q000503:physiopathology; D002560:Cerebrovascular Circulation / Q000502:physiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015424:Reperfusion / Q000379:methods*; D012189:Retrospective Studies; D020521:Stroke / Q000000981:diagnostic imaging* / Q000503:physiopathology; D014057:Tomography, X-Ray Computed