title: Cerebral hemodynamics in relation to patterns of collateral flow.
abstract: OBJECTIVE
  We sought to investigate the relation between collateral flow via different pathways and hemodynamic parameters measured by dynamic susceptibility contrast-enhanced MRI in patients with severe carotid artery disease.
  
  
  METHODS
  Dynamic susceptibility contrast-enhanced MRI was performed in 66 patients and 33 control subjects. Patients had severe stenosis (>70%, n=12), unilateral occlusion (n=38), or bilateral occlusion (n=16) of the internal carotid artery (ICA). Cerebripetal flow and collateral flow via the circle of Willis were investigated with MR angiography. Collateral flow via the ophthalmic artery was investigated with transcranial Doppler sonography.
  
  
  RESULTS
  Patients with ICA stenosis had well-preserved cerebral perfusion and were in general not dependent on collateral supply. Patients with unilateral ICA occlusion had impaired cerebral perfusion. However, appearance time, peak time, and mean transit time in white matter were less increased in patients with than in patients without collateral flow via the circle of Willis (P<0.05). Furthermore, patients with collateral flow via both anterior and posterior communicating arteries had less increased regional cerebral blood volume than patients with collateral flow via the posterior communicating artery only (P<0.05). Patients with bilateral ICA occlusion had severely compromised hemodynamic status despite recruitment of collateral supply.
  
  
  CONCLUSIONS
  In patients with unilateral ICA occlusion, the pattern of collateral supply has significant influence on hemodynamic status. Collateral flow via the anterior communicating artery is a sign of well-preserved hemodynamic status, whereas no collateral flow via the circle of Willis or flow via only the posterior communicating artery is a sign of deteriorated cerebral perfusion.
authors.affiliation: Department of Radiology, Image Sciences Institute, Department of Neurology, University Hospital Utrecht, Utrecht, Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Kluytmans
authors.forename: J
authors.initials: J
authors.lastname: van der Grond
authors.forename: K J
authors.initials: KJ
authors.lastname: van Everdingen
authors.forename: C J
authors.initials: CJ
authors.lastname: Klijn
authors.forename: L J
authors.initials: LJ
authors.lastname: Kappelle
authors.forename: M A
authors.initials: MA
authors.lastname: Viergever
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D002539:Cerebral Arterial Diseases / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002560:Cerebrovascular Circulation; D002941:Circle of Willis / Q000000981:diagnostic imaging / Q000503:physiopathology; D003097:Collateral Circulation; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D017585:Ultrasonography, Doppler, Transcranial