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Updated: Jan 22, 2026
Protocol for Isolating the Mouse Circle of Willis
Published on: October 22, 2016
Association between Circle of Willis Configuration and Rupture of Cerebral Aneurysms
Nebojša N Stojanović1,2, Aleksandar Kostić3,4, Radisav Mitić5,6,7
1Clinic of Neurosurgery, Clinical Center Niš, Zorana Đinđića 48, 18000 Niš, Serbia. nesamed59@gmail.com.
Insights
Asymmetric configurations of the circle of Willis, particularly Type B, are linked to a higher risk of cerebral aneurysm rupture. Identifying these patterns can aid in patient monitoring protocols.
Area of Science:
- Neurology
- Vascular Surgery
- Radiology
Background:
- Cerebral aneurysms affect 4-9% of people, but rupture occurs in only 10 per 100,000 annually.
- Understanding factors influencing aneurysm rupture is crucial for risk stratification.
- The circle of Willis anatomy's role in aneurysm rupture remains an area of investigation.
Purpose of the Study:
- To investigate the association between circle of Willis configurations and cerebral aneurysm rupture.
- To determine if specific anatomical variations increase the likelihood of aneurysm rupture.
Main Methods:
- Analysis of 114 surgically treated ruptured cerebral aneurysm patients.
- Comparison with 56 autopsied subjects.
- Classification of circle of Willis into symmetric (Types A, C) and asymmetric (Types B, D) configurations.
Main Results:
- Significantly higher prevalence of asymmetric circle of Willis (p = 0.001) in ruptured aneurysm patients.
- Asymmetric Type B was significantly associated with ruptured aneurysms (p < 0.001).
- Symmetric configurations (Types A, C) were more prevalent in the autopsied group (p < 0.001).
Conclusions:
- A1 segment changes and resulting circle of Willis asymmetry (hypoplasia/aplasia) are linked to cerebral aneurysm rupture.
- Early detection of specific circle of Willis types can inform patient monitoring strategies.
- This study highlights the importance of vascular anatomy in predicting aneurysm rupture risk.
Abstract:
Background and Objectives: Intracranial hemorrhage caused by the rupture of brain aneurysms occurs in almost 10 per 100,000 people whereas the incidence of such aneurysms is significantly higher, accounting for 4-9%.Linking certain factors to cerebral aneurysm rupture could help in explaining the significantly lower incidence of their rupture compared to their presence. The aim of this study is to determine the association between the corresponding circle of Willis configurations and rupture of cerebral aneurysms.
Materials And Methods:
A group of 114 patients treated operatively for aruptured cerebral aneurysm and a group of 56 autopsied subjects were involved in the study. Four basic types of the circle of Willis configurations were formed-two symmetric types A and C, and two asymmetric types B and D.
Results:
A statistically significantly higher presence of asymmetry of the circle of Willis was determined in the group of surgically-treated subjects (p = 0.001),witha significant presence of asymmetric Type B in this group (p < 0.001). The changeson the A1 segment in the group of surgically-treated subjects showed a statistically significant presence compared to the group of autopsied subjects (p = 0.001). Analyzing the presence of symmetry of the circle of Willis between the two groups, that is, the total presence of symmetric types A and C, indicated their statistically significant presence in the group of autopsied patients (p < 0.001).
Conclusions:
Changes such as hypoplasia or aplasia of A1 and the resulting asymmetry of the circle of Willis directly affect the possibility of the rupture of cerebral aneurysms. Detection of the corresponding types of the circle of Willis after diagnostic examination can be the basis for the development of a protocol for monitoring such patients.
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