The geometry of the circle of willis anatomical variants as a potential cerebrovascular risk factor

Paşcalău, Raluca; Padurean, Vlad Adrian; Bartoş, Dana; Bartoș, Adrian; Szabo, Bianca

doi:10.5137/1019-5149.jtn.21835-17.3

Cited by 33 publications

(46 citation statements)

References 20 publications

(40 reference statements)

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“…Experimental and computational models suggest that increased flow through an abnormal configuration of patent branches increases wall sheer stress leading to aneurysmal formation. [1][2][3][4] Similarly, incomplete configuration increases the risk of ischemic stroke, likely due to reduced collateral circulation. [4,5] An incomplete CoW as a risk factor for stroke and aneurysm formation continues to be a focus of research in cerebrovascular disease.…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3][4] Similarly, incomplete configuration increases the risk of ischemic stroke, likely due to reduced collateral circulation. [4,5] An incomplete CoW as a risk factor for stroke and aneurysm formation continues to be a focus of research in cerebrovascular disease. In 1984, Kayembe et al [6] found aneurysms to be more common in autopsy studies in patients with CoW anatomic variations, a finding suggested by CoW assessment with advanced imaging.…”

Section: Introductionmentioning

confidence: 99%

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Demographic age-related variation in Circle of Willis completeness assessed by digital subtraction angiography

et al. 2020

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Incomplete circle of Willis (CoW) configuration is an important risk factor for cerebrovascular pathology, namely aneurysm formation and ischemic stroke. This study was performed to characterize CoW variation using digital subtraction angiography and to identify demographic and physiologic features that may influence the risk of having an incomplete CoW configuration. MATERIALS AND METHODS: A retrospective review of 274 patients who underwent cerebral angiography by a single surgeon for any indication was conducted. Each CoW branch was graded as normal, hypoplastic, or aplastic. Univariate and multivariate regression analyses were conducted to assess the impact of age, gender, race, and certain comorbidities on CoW configuration. RESULTS: A complete CoW was identified in 37.23% of patients. In univariate analysis, patients <40 years old were more likely to have a complete CoW (odds ratio [OR]: 4.973, 95% confidence interval [CI]: 2.610-9.476, P < 0.001) as were patients <70 years old (OR: 2.849, 95% CI: 1.131-7.194, P < 0.05). Univariate analysis on demographic factors and comorbidities revealed CoW completeness to decrease with hypertension (OR: 0.575, 95% CI: 0.347-0.951, P = 0.031) and diabetes mellitus (OR: 0.368, 95% CI: 0.180-0.754, P = 0.006). Multivariable logistic regression analysis used to assess the impact of age on CoW completeness showed age to be an independent predictor of complete CoW, with an inverse correlation between increasing age and CoW completeness (OR: 0.955, 95% CI: 0.937-0.973, P < 0.001) after controlling for potential confounders including hypertension and diabetes mellitus. CONCLUSIONS: CoW configuration shows considerable variation with age; however, further investigation is required to elucidate the full impact of other demographic and vascular risk factors on CoW anatomy.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Demographic age-related variation in Circle of Willis completeness assessed by digital subtraction angiography

et al. 2020

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“…The inconsistent results on whether a complete CoW may be protective against WMH may hint of a more complex role of the CoW in the cerebrovascular system than just having the role as a compensatory system in case of arterial occlusion. This has been suggested by previous studies (Pascalau et al, 2018;Vrselja et al, 2014). In particular, Vrselja et al argued that the CoW also plays a role in blood pressure dissipation, ensuring lower fluctuations in blood pressure in the downstream cerebral arteries of the CoW (Vrselja et al, 2014).…”

Section: Discussionmentioning

confidence: 60%

An incomplete Circle of Willis is not a risk factor for white matter hyperintensities: The Tromsø Study

Hindenes

Håberg

Mathiesen

et al. 2020

Preprint

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Objective The Circle of Willis (CoW) is often underdeveloped or incomplete, leading to suboptimal blood supply to the brain. As hypoperfusion is thought to play a role in the aetiology of white matter hyperintensities (WMH), the objective of this study was to assess whether incomplete CoW variants were associated with increased WMH volumes compared to the complete CoW. Methods In a cross-sectional population sample of 1864 people (age 40 - 84 years, 46.4% men), we used an automated method to segment WMH using T1-weighted and T2-weighted fluid-attenuated inversion recovery image obtained at 3T. CoW variants were classified from time-of-flight scans, also at 3T. WMH risk factors, including age, sex, smoking and blood pressure, were obtained from questionnaires and clinical examinations. We used linear regression to examine whether people with incomplete CoW variants had greater volumes of deep WMH (DWMH) and periventricular WMH (PWMH) compared to people with the complete CoW, correcting for WMH risk factors. Results Participants with incomplete CoW variants did not have significantly higher DWMH or PWMH volumes than those with complete CoW when accounting for risk factors. Age, pack-years smoking, and systolic blood pressure were risk factors for increased DWMH and PWMH volume. Diabetes was a unique risk factor for increased PWMH volume. Conclusion Incomplete CoW variants do not appear to be risk factors for WMH in the general population.

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“…"is there a general vulnerability in the right MCA area for ischemia", mechanistic simulations might be able to provide this information instead of direct perfusion measurements. Also, since many variants of the CoW exist, the simulation could allow the identification of patients with high-risk for stroke owing to their individual CoW configuration (Pascalau et al 2018).…”

Section: Discussionmentioning

confidence: 99%

A Precision Medicine Framework for Personalized Simulation of Hemodynamics in Cerebrovascular Disease

Frey

Livne

Leppin

et al. 2020

Preprint

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Introduction Cerebrovascular disease is a major public health challenge. An important biomarker is cerebral hemodynamics. To measure cerebral hemodynamics, however, only invasive, potentially harmful or time-to-treatment prolonging methods are available. We present a simulation-based alternative which allows calculation of cerebral hemodynamics based on the individual vessel configuration of a patient derived from structural vessel imaging. Methods We implemented a framework allowing annotation of extracted brain vessels from structural imaging followed by 0-dimensional lumped modelling of cerebral hemodynamics. For annotation, a 3D-graphical user interface (GUI) was implemented. For 0D-simulation, we used a modified nodal analysis (MNA), which was adapted for easy implementation by code. The code was written in-house in java. The simulation GUI allows inspection of simulation results, identification of vulnerable areas, simulation of changes due to different systemic blood pressures. Moreover, sensitivity analysis was implemented allowing the live simulation of changes of variables such as vessel lumen to simulate procedures and disease courses. In two exemplary patients, simulation results were compared to dynamic-susceptibility-weighted-contrast-enhanced magnetic-resonance(DSC-MR) perfusion imaging. Results The successful implementation of the framework allowing individualized annotation and simulation of patients is presented. In two exemplary patients, both the simulation as well as DSC-MRI showed the same results pertaining to the identification of areas vulnerable to ischemia. Sensitivity analysis allows the individualized simulation of changes in vessel lumen and the effect on hemodynamics. Discussion We present the first precision medicine pipeline for cerebrovascular disease which allows annotation of the arterial vasculature derived from structural vessel imaging followed by personalized simulation of brain hemodynamics. This paves the way for further development of precision medicine in stroke using novel biomarkers and might make the application of harmful and complex perfusion methods obsolete for certain use cases in the future.

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The geometry of the circle of willis anatomical variants as a potential cerebrovascular risk factor

Abstract: We described anatomical variants of both the anterior and posterior circulations and their specific effects on the hemodynamic balance of cerebral blood flow.

Cited by 33 publications

References 20 publications

Demographic age-related variation in Circle of Willis completeness assessed by digital subtraction angiography

Demographic age-related variation in Circle of Willis completeness assessed by digital subtraction angiography

An incomplete Circle of Willis is not a risk factor for white matter hyperintensities: The Tromsø Study

A Precision Medicine Framework for Personalized Simulation of Hemodynamics in Cerebrovascular Disease

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