In a recent study, researchers found no significant difference in the completeness of the circle of Willis (CoW) in acute stroke patients with migraine compared to those without. Participants were recruited from a prospective acute stroke study. All underwent CT angiography on admission. Lifetime migraine history was assessed with a screening questionnaire and confirmed by an interview based on International Classification of Headache Disorders criteria. The CoW was assessed for incompleteness/hypoplasia (any segment <1 mm), for anterior cerebral artery asymmetry (difference >1/3), and for posterior communicating artery (Pcom) dominance (Pcom–P1 difference >1/3). They found:

• Included were 646 participants with stroke, of whom 52 had a history of migraine.
• Of these, 45 (87%) had an incomplete or hypoplastic CoW vs 506 (85%) of the 594 participants without migraine (adjusted odds ratio [aOR]:1.47).
• There were no differences between participants with and without migraine in variations of the anterior or posterior CoW, anterior cerebral artery asymmetry (aOR 0.86), or Pcom dominance (aOR:0.64).
• There were no differences in CoW variations between migraine patients with or without aura.