title: Inferring origin of vascular supply from tracer arrival timing patterns using bolus tracking MRI.
abstract: OBJECTIVE
  To investigate the potential of novel postprocessing and visualization techniques to distinguish presence of collateral flow using Bolus Tracking MRI. Collateral blood supply is believed to be of paramount importance in acute stroke, yet clinical evaluation is challenging as the gold standard digital subtraction angiography is often not feasible in the acute scenario.
  
  
  METHODS
  In principle, bolus arrival delay data contains information about the route of blood supply into tissue and hereby presence of collateral flow patterns. We first examined the potential of current clinical bolus tracking protocols to accurately characterize bolus arrival delay. Using the simulation results, we analyzed bolus tracking data from one normal volunteer and one acute stroke patient.
  
  
  RESULTS
  The bolus arrival patterns in the volunteer and in the normal hemisphere of the patient were found to be qualitatively similar and in good agreement with physiology. The bolus was seen to spread from the larger arteries toward the periphery. The stroke hemisphere in the patient indicated a retrograde direction of flow on the cortical mantle consistent with leptomeningeal vessels.
  
  
  CONCLUSIONS
  Bolus tracking MRI can likely be used to distinguish collateral flow patterns from normal flow patterns.
authors.affiliation: Center for Functionally Integrative Neuroscience, Arhus University Hospital, Arhus, Denmark. chr@pet.auh.dk
authors.forename: Søren
authors.initials: S
authors.lastname: Christensen
authors.forename: Fernando
authors.initials: F
authors.lastname: Calamante
authors.forename: Niels
authors.initials: N
authors.lastname: Hjort
authors.forename: Ona
authors.initials: O
authors.lastname: Wu
authors.forename: Anne Dorte
authors.initials: AD
authors.lastname: Blankholm
authors.forename: Patricia
authors.initials: P
authors.lastname: Desmond
authors.forename: Stephen
authors.initials: S
authors.lastname: Davis
authors.forename: Leif
authors.initials: L
authors.lastname: Ostergaard
mesh_terms: D000328:Adult; D001931:Brain Mapping; D002560:Cerebrovascular Circulation; D003097:Collateral Circulation; D003198:Computer Simulation / Q000706:statistics & numerical data; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D017352:Echo-Planar Imaging / Q000379:methods; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D015203:Reproducibility of Results; D020521:Stroke / Q000503:physiopathology*; D013997:Time Factors