title: Migraine without aura is not associated with incomplete circle of Willis: a case-control study using high-resolution magnetic resonance angiography.
abstract: BACKGROUND
  The circle of Willis is an important source of collateral blood flow to maintain adequate cerebral perfusion, particularly in the posterior circulation. Some studies report a relationship between incomplete circle of Willis and migraine, whereas other studies show no difference between the prevalence of incomplete circle of Willis in migraineurs and controls. In the present study we compared the prevalence of incomplete circle of Willis in female migraine patients without aura to female healthy non-migraine controls.Using 3-Tesla magnetic resonance angiography we recorded three-dimensional time-of-flight angiograms in 85 female participants (48 migraine patients without aura [median age 28 years] and 37 healthy controls [median age 25 years]). The images were subsequently analysed blindly by a neuroradiologist to detect incomplete circle of Willis.
  
  
  RESULTS
  We found no difference between the prevalence of incomplete circle of Willis in patients, 20/47 (43%), and controls, 15/37 (41%), p = 0.252. Post hoc analysis showed a significant relationship between age and prevalence of incomplete circle of Willis, p = 0.003.
  
  
  CONCLUSIONS
  We found no relationship between migraine without aura and incomplete circle of Willis.
authors.forename: Shabnam
authors.initials: S
authors.lastname: Ezzatian-Ahar
authors.forename: Faisal Mohammad
authors.initials: FM
authors.lastname: Amin
authors.forename: Hayder Ghani
authors.initials: HG
authors.lastname: Obaid
authors.forename: Nanna
authors.initials: N
authors.lastname: Arngrim
authors.forename: Anders
authors.initials: A
authors.lastname: Hougaard
authors.forename: Henrik B W
authors.initials: HB
authors.lastname: Larsson
authors.affiliation: Danish Headache Center, Department of Neurology, Glostrup Hospital, University of Copenhagen, Nordre Ringvej 57, Glostrup DK-2600, Denmark. ashina@dadlnet.dk.
authors.forename: Messoud
authors.initials: M
authors.lastname: Ashina
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D002941:Circle of Willis / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography; D008875:Middle Aged; D020326:Migraine without Aura / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011859:Radiography; D055815:Young Adult