title: Importance of variants in cerebrovascular anatomy for potential retrograde embolization in cryptogenic stroke.
abstract: OBJECTIVE
  To test the hypothesis that variants in cerebrovascular anatomy will affect the number of patients demonstrating a plausible retrograde embolization mechanism from plaques in the descending aorta (DAo).
  
  
  METHODS
  Thirty-five patients (aged 63 ± 17 years) with cryptogenic stroke underwent 4D flow MRI for the assessment of aortic 3D blood flow and MR angiography for the evaluation of circle of Willis, posterior circulation, and aortic arch architecture. In patients with proven DAo plaque, retrograde embolization was considered a potential mechanism if retrograde flow extended from the DAo to a supra-aortic vessel supplying the cerebral infarct territory.
  
  
  RESULTS
  Retrograde embolization with matching cerebral infarct territory was detected in six (17%) patients. Circle of Willis and aortic arch variant anatomy was found in 60% of patients, leading to reclassification of retrograde embolization risk as present in three (9%) additional patients, for a total 26% of cryptogenic stroke patients.
  
  
  CONCLUSIONS
  4D flow MRI demonstrated 26% concordance with infarct location on imaging with retrograde diastolic flow into the feeding vessels of the affected cerebral area, identifying a potential etiology for cryptogenic stroke. Our findings further demonstrate the importance of cerebrovascular anatomy when determining concordance of retrograde flow pathways with vascular stroke territory from DAo plaques.
  
  
  CONCLUSIONS
  • Retrograde embolization from descending aortic plaques constitutes a plausible etiology in cryptogenic stroke. • Common variants of cerebrovascular anatomy are important in determining retrograde embolization mechanism. • Variant cerebrovascular anatomy can link retrograde flow pathways with vascular stroke territory.
authors.affiliation: Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA. mmarkl@northwestern.edu.|Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, IL, USA. mmarkl@northwestern.edu.
authors.forename: Michael
authors.initials: M
authors.lastname: Markl
authors.affiliation: Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
authors.forename: Edouard
authors.initials: E
authors.lastname: Semaan
authors.affiliation: Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.|Department of Radiology, Edward Hospital, Naperville, IL, USA.
authors.forename: LeRoy
authors.initials: L
authors.lastname: Stromberg
authors.affiliation: Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
authors.forename: James
authors.initials: J
authors.lastname: Carr
authors.affiliation: Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
authors.forename: Shyam
authors.initials: S
authors.lastname: Prabhakaran
authors.affiliation: Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Collins
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D063405:Anatomic Variation; D001013:Aorta, Thoracic / Q000002:abnormalities / Q000000981:diagnostic imaging*; D002544:Cerebral Infarction / Q000000981:diagnostic imaging* / Q000209:etiology; D002560:Cerebrovascular Circulation; D002941:Circle of Willis / Q000002:abnormalities / Q000000981:diagnostic imaging*; D005260:Female; D006439:Hemodynamics; D006801:Humans; D018810:Magnetic Resonance Angiography; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D058226:Plaque, Atherosclerotic / Q000150:complications / Q000000981:diagnostic imaging*; D020521:Stroke / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology
keywords: 4D flow MRI; Circle of Willis; Plaque; Retrograde flow; Stroke