title: Sensitivity and specificity of the hyperdense artery sign for arterial obstruction in acute ischemic stroke.
abstract: OBJECTIVE
  In acute ischemic stroke, the hyperdense artery sign (HAS) on noncontrast computed tomography (CT) is thought to represent intraluminal thrombus and, therefore, is a surrogate of arterial obstruction. We sought to assess the accuracy of HAS as a marker of arterial obstruction by thrombus.
  
  
  METHODS
  The Third International Stroke Trial (IST-3) was a randomized controlled trial testing the use of intravenous thrombolysis for acute ischemic stroke in patients who did not clearly meet the prevailing license criteria. Some participating IST-3 centers routinely performed CT or MR angiography at baseline. One reader assessed all relevant scans independently, blinded to all other data; we checked observer reliability. We combined IST-3 data with a systematic review and meta-analysis of all studies that assessed the accuracy of HAS using angiography (any modality).
  
  
  RESULTS
  IST-3 had 273 patients with baseline CT or MR angiography and was the largest study of HAS accuracy. The meta-analysis (n=902+273=1175, including IST-3) found sensitivity and specificity of HAS for arterial obstruction on angiography to be 52% and 95%, respectively. HAS was more commonly identified in proximal than distal arteries (47% versus 37%; P=0.015), and its sensitivity increased with thinner CT slices (r=-0.73; P=0.001). Neither extent of obstruction nor time after stroke influenced HAS accuracy.
  
  
  CONCLUSIONS
  When present in acute ischemic stroke, HAS indicates a high likelihood of arterial obstruction, but its absence indicates only a 50/50 chance of normal arterial patency. Thin-slice CT improves sensitivity of HAS detection.
  
  
  BACKGROUND
  http://www.controlled-trials.com/ISRCTN25765518. Unique identifier: ISRCTN25765518.
authors.affiliation: From the Division of Neuroimaging Sciences, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom (G.M., F.M.C., P.S., J.M.W.); Department of Radiology, Northwick Park Hospital, Harrow, United Kingdom (E.V.B.); Department of Neuroradiology, Dresden University Stroke Centre, University Hospital, Dresden, Germany (R.v.K.); and Westmead Hospital Clinical School and The George Institute for Global Health, University of Sydney, Sydney, New South Wales, Australia (R.I.L.).
authors.forename: Grant
authors.initials: G
authors.lastname: Mair
authors.affiliation: From the Division of Neuroimaging Sciences, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom (G.M., F.M.C., P.S., J.M.W.); Department of Radiology, Northwick Park Hospital, Harrow, United Kingdom (E.V.B.); Department of Neuroradiology, Dresden University Stroke Centre, University Hospital, Dresden, Germany (R.v.K.); and Westmead Hospital Clinical School and The George Institute for Global Health, University of Sydney, Sydney, New South Wales, Australia (R.I.L.).
authors.forename: Elena V
authors.initials: EV
authors.lastname: Boyd
authors.affiliation: From the Division of Neuroimaging Sciences, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom (G.M., F.M.C., P.S., J.M.W.); Department of Radiology, Northwick Park Hospital, Harrow, United Kingdom (E.V.B.); Department of Neuroradiology, Dresden University Stroke Centre, University Hospital, Dresden, Germany (R.v.K.); and Westmead Hospital Clinical School and The George Institute for Global Health, University of Sydney, Sydney, New South Wales, Australia (R.I.L.).
authors.forename: Francesca M
authors.initials: FM
authors.lastname: Chappell
authors.affiliation: From the Division of Neuroimaging Sciences, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom (G.M., F.M.C., P.S., J.M.W.); Department of Radiology, Northwick Park Hospital, Harrow, United Kingdom (E.V.B.); Department of Neuroradiology, Dresden University Stroke Centre, University Hospital, Dresden, Germany (R.v.K.); and Westmead Hospital Clinical School and The George Institute for Global Health, University of Sydney, Sydney, New South Wales, Australia (R.I.L.).
authors.forename: Rüdiger
authors.initials: R
authors.lastname: von Kummer
authors.affiliation: From the Division of Neuroimaging Sciences, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom (G.M., F.M.C., P.S., J.M.W.); Department of Radiology, Northwick Park Hospital, Harrow, United Kingdom (E.V.B.); Department of Neuroradiology, Dresden University Stroke Centre, University Hospital, Dresden, Germany (R.v.K.); and Westmead Hospital Clinical School and The George Institute for Global Health, University of Sydney, Sydney, New South Wales, Australia (R.I.L.).
authors.forename: Richard I
authors.initials: RI
authors.lastname: Lindley
authors.affiliation: From the Division of Neuroimaging Sciences, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom (G.M., F.M.C., P.S., J.M.W.); Department of Radiology, Northwick Park Hospital, Harrow, United Kingdom (E.V.B.); Department of Neuroradiology, Dresden University Stroke Centre, University Hospital, Dresden, Germany (R.v.K.); and Westmead Hospital Clinical School and The George Institute for Global Health, University of Sydney, Sydney, New South Wales, Australia (R.I.L.).
authors.forename: Peter
authors.initials: P
authors.lastname: Sandercock
authors.affiliation: From the Division of Neuroimaging Sciences, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom (G.M., F.M.C., P.S., J.M.W.); Department of Radiology, Northwick Park Hospital, Harrow, United Kingdom (E.V.B.); Department of Neuroradiology, Dresden University Stroke Centre, University Hospital, Dresden, Germany (R.v.K.); and Westmead Hospital Clinical School and The George Institute for Global Health, University of Sydney, Sydney, New South Wales, Australia (R.I.L.). joanna.wardlaw@ed.ac.uk.
authors.forename: Joanna M
authors.initials: JM
authors.lastname: Wardlaw
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001157:Arterial Occlusive Diseases / Q000150:complications / Q000000981:diagnostic imaging*; D002545:Brain Ischemia / Q000150:complications / Q000000981:diagnostic imaging* / Q000188:drug therapy; D002533:Cerebral Angiography; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use; D006801:Humans; D008297:Male; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D020521:Stroke / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000209:etiology; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use; D014057:Tomography, X-Ray Computed
chemical_list: D005343:Fibrinolytic Agents; D010959:Tissue Plasminogen Activator
keywords: angiography; meta-analysis; stroke