title: Collateral vessels on CT angiography predict outcome in acute ischemic stroke.
abstract: OBJECTIVE
  Despite the abundance of emerging multimodal imaging techniques in the field of stroke, there is a paucity of data demonstrating a strong correlation between imaging findings and clinical outcome. This study explored how proximal arterial occlusions alter flow in collateral vessels and whether occlusion or extent of collaterals correlates with prehospital symptoms of fluctuation and worsening since onset or predict in-hospital worsening.
  
  
  METHODS
  Among 741 patients enrolled in a prospective cohort study involving CT angiographic imaging in acute stroke, 134 cases with proximal middle cerebral artery occlusion and 235 control subjects with no occlusions were identified. CT angiography was used to identify occlusions and grade the extent of collateral vessels in the sylvian fissure and leptomeningeal convexity. History of symptom fluctuation or progressive worsening was obtained on admission.
  
  
  RESULTS
  Prehospital symptoms were unrelated to occlusion or collateral status. In cases, 37.5% imaged within 1 hour were found to have diminished collaterals versus 12.1% imaged at 12 to 24 hours (P=0.047). No difference in worsening was seen between cases and control subjects with adequate collaterals, but cases with diminished sylvian and leptomeningeal collaterals experienced greater risk of worsening compared with control subjects measured either by admission to discharge National Institutes of Health Stroke Scale increase > or =1 (55.6% versus 16.6%, P=0.001) or > or =4 (44.4% versus 6.4%, P<0.001).
  
  
  CONCLUSIONS
  Most patients with proximal middle cerebral artery occlusion rapidly recruit sufficient collaterals and follow a clinical course similar to patients with no occlusions, but a subset with diminished collaterals is at high risk for worsening.
authors: Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Mass, USA. mmaas@partners.org
authors: Matthew B
authors: MB
authors: Maas
authors: Michael H
authors: MH
authors: Lev
authors: Hakan
authors: H
authors: Ay
authors: Aneesh B
authors: AB
authors: Singhal
authors: David M
authors: DM
authors: Greer
authors: Wade S
authors: WS
authors: Smith
authors: Gordon J
authors: GJ
authors: Harris
authors: Elkan
authors: E
authors: Halpern
authors: André
authors: A
authors: Kemmling
authors: Walter J
authors: WJ
authors: Koroshetz
authors: Karen L
authors: KL
authors: Furie
mesh_terms: D000208:Acute Disease; D002533:Cerebral Angiography / Q000379:methods*; D002560:Cerebrovascular Circulation; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000000981:diagnostic imaging*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D020521:Stroke / Q000000981:diagnostic imaging*; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods*