title: Hyperintense Vessels on FLAIR: Hemodynamic Correlates and Response to Thrombolysis.
abstract: OBJECTIVE
  Hyperintense vessels on baseline FLAIR MR imaging of patients with ischemic stroke have been linked to leptomeningeal collateralization, yet the ability of these to maintain viable ischemic tissue remains unclear. We investigated whether hyperintense vessels on FLAIR are associated with the severity of hypoperfusion and response to thrombolysis in patients treated with intravenous tissue-plasminogen activator.
  
  
  METHODS
  Consecutive patients with ischemic stroke with an MR imaging before and within 24 hours of treatment, with proved vessel occlusion and available time-to-maximum maps were included (n = 62). The severity of hypoperfusion was characterized on the basis of the hypoperfusion intensity ratio (volume with severe/mild hypoperfusion [time-to-maximum ≥ 8 seconds / time-to-maximum ≥ 2 seconds]). The hypoperfusion intensity ratio was dichotomized at the median to differentiate moderate (hypoperfusion intensity ratio ≤ 0.447) and severe (hypoperfusion intensity ratio > 0.447) hypoperfusion. Good outcome was defined as a modified Rankin Scale score of ≤2.
  
  
  RESULTS
  Hyperintense vessels on FLAIR were identified in 54 patients (87%). Patients with extensive hyperintense vessels on FLAIR (>4 sections) had higher NIHSS scores, larger baseline lesion volumes, higher rates of perfusion-diffusion mismatch, and more severe hypoperfusion (hypoperfusion intensity ratio). In stepwise backward multivariate regression analysis for the dichotomized hypoperfusion intensity ratio (including stroke etiology, age, perfusion deficit, baseline lesion volume, smoking, and extent of hyperintense vessels on FLAIR), extensive hyperintense vessels on FLAIR were independently associated with severe hypoperfusion (OR, 6.8; 95% CI, 1.1-42.7; P = .04). The hypoperfusion intensity ratio was an independent predictor of a worse functional outcome at 3 months poststroke (OR, 0.2; 95% CI, 0.5-0.6; P < .01).
  
  
  CONCLUSIONS
  Hyperintense vessels on FLAIR are associated with larger perfusion deficits, larger infarct growth, and more severe hypoperfusion, suggesting that hyperintense vessels on FLAIR most likely indicate severe ischemia as a result of insufficient collateralization.
authors.affiliation: From the Klinik und Hochschulambulanz für Neurologie (A.K., C.H.N., M. Endres, M. Ebinger) International Graduate Program Medical Neurosciences (A.K., V.A.) anna.kufner@charite.de.
authors.forename: A
authors.initials: A
authors.lastname: Kufner
authors.affiliation: Center for Stroke Research Berlin (I.G., C.H.N., M. Endres, J.B.F., M. Ebinger), Berlin, Germany.
authors.forename: I
authors.initials: I
authors.lastname: Galinovic
authors.affiliation: International Graduate Program Medical Neurosciences (A.K., V.A.).
authors.forename: V
authors.initials: V
authors.lastname: Ambrosi
authors.affiliation: From the Klinik und Hochschulambulanz für Neurologie (A.K., C.H.N., M. Endres, M. Ebinger) Center for Stroke Research Berlin (I.G., C.H.N., M. Endres, J.B.F., M. Ebinger), Berlin, Germany.
authors.forename: C H
authors.initials: CH
authors.lastname: Nolte
authors.affiliation: From the Klinik und Hochschulambulanz für Neurologie (A.K., C.H.N., M. Endres, M. Ebinger) Cluster of Excellence NeuroCure (M. Endres), Charité-Universitätsmedizin Berlin, Berlin, Germany Center for Stroke Research Berlin (I.G., C.H.N., M. Endres, J.B.F., M. Ebinger), Berlin, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Endres
authors.affiliation: Center for Stroke Research Berlin (I.G., C.H.N., M. Endres, J.B.F., M. Ebinger), Berlin, Germany.
authors.forename: J B
authors.initials: JB
authors.lastname: Fiebach
authors.affiliation: From the Klinik und Hochschulambulanz für Neurologie (A.K., C.H.N., M. Endres, M. Ebinger) Center for Stroke Research Berlin (I.G., C.H.N., M. Endres, J.B.F., M. Ebinger), Berlin, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Ebinger
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003097:Collateral Circulation / Q000502:physiology; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006439:Hemodynamics; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000188:drug therapy* / Q000503:physiopathology*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D020521:Stroke / Q000188:drug therapy* / Q000503:physiopathology*; D015912:Thrombolytic Therapy