title: Relative cerebral blood volume as a marker of durable tissue-at-risk viability in hyperacute ischemic stroke.
abstract: OBJECTIVE
  Selection of best responders to reperfusion therapies could be aided by predicting the duration of tissue-at-risk viability, which may be dependant on collateral circulation status. We aimed to identify the best predictor of good collateral circulation among perfusion computed tomography (PCT) parameters in middle cerebral artery (MCA) ischemic stroke and to analyze how early MCA response to intravenous thrombolysis and PCT-derived markers of good collaterals interact to determine stroke outcome.
  
  
  METHODS
  We prospectively studied patients with acute MCA ischemic stroke treated with intravenous thrombolysis who underwent PCT before treatment showing a target mismatch profile. Collateral status was assessed using a PCT source image-based score. PCT maps were quantitatively analyzed. Cerebral blood volume (CBV), cerebral blood flow, and Tmax were calculated within the hypoperfused volume and in the equivalent region of unaffected hemisphere. Occluded MCAs were monitored by transcranial Duplex to assess early recanalization. Main outcome variables were brain hypodensity volume and modified Rankin scale score at day 90.
  
  
  RESULTS
  One hundred patients with MCA ischemic stroke imaged by PCT received intravenous thrombolysis, and 68 met all inclusion criteria. A relative CBV (rCBV) >0.93 emerged as the only predictor of good collaterals (odds ratio, 12.6; 95% confidence interval, 2.9-55.9; P=0.001). Early MCA recanalization was associated with better long-term outcome and lower infarct volume in patients with rCBV<0.93, but not in patients with high rCBV. None of the patients with rCBV<0.93 achieved good outcome in absence of early recanalization.
  
  
  CONCLUSIONS
  High rCBV was the strongest marker of good collaterals and may characterize durable tissue-at-risk viability in hyperacute MCA ischemic stroke.
authors.affiliation: From the Stroke Unit, Department of Neurology (E.C., A.I.C., P.M., J.R., J.F.A.), Section of Neuroradiology, Department of Radiology (S.P.-F., M.M.-G.), and Research Support Unit (M.F.M.), Hospital Clínico Universitario, Valladolid, Spain; Department of Medicine, Universidad de Valladolid, Valladolid, Spain (P.G.-B.); and Department of Neurosciences, Hospital Universitari Germans Trias i Pujol, Barcelona, Spain (P.G.-B.).
authors.forename: Elisa
authors.initials: E
authors.lastname: Cortijo
authors.forename: Ana Isabel
authors.initials: AI
authors.lastname: Calleja
authors.forename: Pablo
authors.initials: P
authors.lastname: García-Bermejo
authors.forename: Patricia
authors.initials: P
authors.lastname: Mulero
authors.forename: Santiago
authors.initials: S
authors.lastname: Pérez-Fernández
authors.forename: Javier
authors.initials: J
authors.lastname: Reyes
authors.forename: Ma Fe
authors.initials: MF
authors.lastname: Muñoz
authors.forename: Mario
authors.initials: M
authors.lastname: Martínez-Galdámez
authors.forename: Juan Francisco
authors.initials: JF
authors.lastname: Arenillas
mesh_terms: D000368:Aged; D015415:Biomarkers; D001810:Blood Volume / Q000502:physiology*; D002545:Brain Ischemia / Q000097:blood* / Q000473:pathology*; D002560:Cerebrovascular Circulation / Q000502:physiology; D003097:Collateral Circulation / Q000502:physiology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D020244:Infarction, Middle Cerebral Artery / Q000097:blood / Q000473:pathology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D020521:Stroke / Q000097:blood* / Q000473:pathology*; D015912:Thrombolytic Therapy; D014057:Tomography, X-Ray Computed
chemical_list: D015415:Biomarkers
keywords: arterial recanalization; collateral circulation; ischemic stroke; perfusion computed tomography; thrombolytic therapy