title: Leptomeningeal collateral volume flow assessed by quantitative magnetic resonance angiography in large-vessel cerebrovascular disease.
abstract: OBJECTIVE
  Leptomeningeal collateral volume flow has not been previously quantified. Quantitative magnetic resonance angiography (QMRA) can determine flow in the large vessels of the intracranial circulation.
  
  
  METHODS
  We reviewed consecutive QMRA studies performed between December 1, 2004 and August 30, 2005, for cases showing asymmetrically higher flow in a posterior cerebral artery (PCA) just distal to the origin of the posterior communicating artery ipsilateral to a hemodynamic middle cerebral artery (MCA) or internal carotid artery lesion. The mean, range, and standard deviation (SD) of the flow rate in the PCAs, MCAs, and PCA ipsilateral-contralateral difference were calculated. Ipsilateral and contralateral PCA flow rates were compared using the Student's t-test.
  
  
  RESULTS
  Sixteen studies met selection criteria. Mean age was 52 years (range 21-79) and 9 were female. MCA flow was below QMRA detection limits in 6 studies. Mean measurable ipsilateral MCA flow reduction was 84 mL/min (range 9-147, SD 51.4). Mean ipsilateral PCA flow was 118 mL/min (range 72-206, SD 38.5) and mean contralateral PCA flow was 68 mL/min (range 35-144, SD 30.5, P < .001); mean difference was 50 mL/min (range 10-93, SD 24.3).
  
  
  CONCLUSIONS
  Leptomeningeal collateral flow can be assessed with QMRA and may be substantial.
authors.affiliation: Department of Neurology and Rehabilitation, University of Illinois at Chicago, Chicago, IL, USA. sruland@uic.edu
authors.forename: Sean
authors.initials: S
authors.lastname: Ruland
authors.forename: Aiesha
authors.initials: A
authors.lastname: Ahmed
authors.forename: Kurian
authors.initials: K
authors.lastname: Thomas
authors.forename: Meide
authors.initials: M
authors.lastname: Zhao
authors.forename: Sepideh
authors.initials: S
authors.lastname: Amin-Hanjani
authors.forename: Xinjian
authors.initials: X
authors.lastname: Du
authors.forename: Fady T
authors.initials: FT
authors.lastname: Charbel
mesh_terms: D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity; D002561:Cerebrovascular Disorders / Q000503:physiopathology*; D003097:Collateral Circulation; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008578:Meninges / Q000098:blood supply*; D008875:Middle Aged; D012189:Retrospective Studies