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Protocol for Isolating the Mouse Circle of Willis
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Distribution of cerebral blood flow in the circle of Willis

Jeroen Hendrikse1, A Fleur van Raamt, Yolanda van der Graaf

  • 1Department of Radiology, University Medical Center Utrecht, PO Box 85500, Hp E 01.132, 3508 GA Utrecht, the Netherlands. j.hendrikse@azu.nl

Radiology
|March 8, 2005
PubMed

Insights

Anatomic variations in the circle of Willis significantly impact blood flow in the internal carotid arteries (ICAs) and basilar artery (BA). These variations, not vascular disease, can explain flow asymmetries and reductions.

Area of Science:

  • Neurovascular anatomy
  • Cerebral blood flow dynamics
  • Medical imaging analysis

Background:

  • The circle of Willis is a critical arterial anastomosis at the base of the brain.
  • Anatomic variations in the circle of Willis are common.
  • Understanding these variations' impact on cerebral blood flow is essential for accurate diagnosis.

Purpose of the Study:

  • To prospectively evaluate the influence of circle of Willis anatomic variations on internal carotid artery (ICA) and basilar artery (BA) volume flow.
  • To differentiate flow changes due to anatomy versus pathology.

Main Methods:

  • Phase-contrast and time-of-flight MR angiography were used in 208 patients.
  • Volume flow in ICAs and BA was measured and normalized for age.
  • Circle of Willis anatomy (complete, missing A1 segment, fetal-type PCA) was assessed.

Main Results:

  • A missing A1 segment correlated with increased contralateral ICA flow.
  • Fetal-type posterior cerebral arteries were associated with increased ICA flow and decreased BA flow.
  • Significant differences (P < .01) were observed between anatomical configurations.

Conclusions:

  • Anatomic variations of the circle of Willis are a significant determinant of ICA and BA volume flow.
  • Observed asymmetries or decreases in cerebral arterial flow may be attributable to anatomical variations rather than steno-occlusive disease.
Abstract

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