scholarly journals The Role Of Circle Of Willis Anatomy Variations In Cardio-embolic Stroke - A Patient-specific Simulation Based Study

2017 ◽  
Author(s):  
Debanjan Mukherjee ◽  
Neel D. Jani ◽  
Jared Narvid ◽  
Shawn C. Shadden
Keyword(s):  
Cerebral Arteries ◽  
Density Ratio ◽  
Flow Simulation ◽  
Anatomical Variations ◽  
Circle Of Willis ◽  
Patient Specific ◽  
Simulation Based ◽  
Flow Through ◽  
The Brain

AbstractWe describe a patient-specific simulation based investigation on the role of Circle of Willis anatomy in cardioembolic stroke. Our simulation framework consists of medical image-driven modeling of patient anatomy including the Circle, 3D blood flow simulation through patient vasculature, embolus transport modeling using a discrete particle dynamics technique, and a sampling based approach to incorporate parametric variations. A total of 24 (four patients and six Circle anatomies including the complete Circle) models were considered, with cardiogenic emboli of varying sizes and compositions released virtually and tracked to compute distribution to the brain. The results establish that Circle anatomical variations significantly influence embolus distribution to the six major cerebral arteries. Embolus distribution to MCA territory is found to be least sensitive to the influence of anatomical variations. For varying Circle topologies, differences in flow through cervical vasculature are observed. This incoming flow is recruited differently across the communicating arteries of the Circle for varying anastomoses. Emboli interact with the routed flow, and can undergo significant traversal across the Circle arterial segments, depending upon their inertia and density ratio with respect to blood. This interaction drives the underlying biomechanics of embolus transport across the Circle, explaining how Circle anatomy influences embolism risk.

MODELING REDISTRIBUTION CEREBRAL CIRCULATION

2021 ◽  
Vol 1 (4) ◽  
pp. 13-18
Author(s):  
Vladislav Nikolaevich Nikitin ◽  
◽  
Ekaterina Valerevna Kozhemyakina ◽  
Keyword(s):  
Blood Flow ◽  
Internal Carotid ◽  
Cerebral Arteries ◽  
Circle Of Willis ◽  
Entire Body ◽  
Compensatory Mechanisms ◽  
Vertebral Arteries ◽  
The Central Nervous System ◽  
Flow Through ◽  
The Brain

The brain is one of the most important organs responsible for the health and functioning of the entire body. The blood supply to the brain is carried out through 2 internal carotid and 2 vertebral arteries in norm. The brain, like other body systems, has protective (compensatory) mechanisms aimed at maintaining the necessary blood flow, one of which is the circle of Willis. The article proposes a mechanism for how blood flow is redistributed through the arteries feeding the brain, which is based on the assumption that the central nervous system controls in such a way that it minimizes flows through the connective arteries of the circle of Willis, the flows along which are normal (with symmetry of the left and right sides) practically equal to zero. Сase of the structure of the circle of Willis is considered in norm. The indicated redistribution mechanism is still only the first step towards an attempt to predict cases of changes in blood flow through the cerebral arteries, especially in stroke. In further works, it is planned to consider the inverse problem, i.e. determine the flows through the internal carotid and vertebral arteries, provided that the flows through the cerebral arteries extending from the circle of Willis have normal flow values.

An Experimental Study of the Effects Anatomical Variations Have on Collateral Flows Within the Circle of Willis

2011 ◽  
Author(s):  
Paul Fahy ◽  
Patrick Delassus ◽  
Padraig O’Flynn ◽  
Liam Morris
Keyword(s):  
Experimental Study ◽  
Blood Flow ◽  
Cerebral Arteries ◽  
Anatomical Variations ◽  
Flow Patterns ◽  
Circle Of Willis ◽  
Collateral Flow ◽  
Arterial Network ◽  
Flow Feature ◽  
The Brain

The circle of Willis (CoW) is a complex arterial network comprising of major cerebral arteries that converge to form a pentagonal arrangement as shown in Figure 1(A). This arterial network supplies oxygen-enriched blood to the brain. An incomplete CoW can exist in up to 50% of cases [1]. These missing vessels can be accommodated by the collateral flow feature within the CoW configuration. In certain circumstances, anatomical variations within the CoW can result in undesirable flow patterns [2–3]. It is unclear from the literature what effects these variations can have on blood flow collision paths within a complete CoW.

scholarly journals The Role of Circle of Willis Anatomy Variations in Cardio-embolic Stroke: A Patient-Specific Simulation Based Study

2018 ◽  
Vol 46 (8) ◽  
pp. 1128-1145 ◽  
Author(s):  
Debanjan Mukherjee ◽  
Neel D. Jani ◽  
Jared Narvid ◽  
Shawn C. Shadden
Keyword(s):  
Circle Of Willis ◽  
Embolic Stroke ◽  
Patient Specific ◽  
Simulation Based

scholarly journals Average dimensions of the vessels at the base of the brain and the embryological basis of its variations

2013 ◽  
Vol 02 (04) ◽  
pp. 180-189
Author(s):  
Iqbal S.
Keyword(s):  
Anterior Part ◽  
Cerebral Arteries ◽  
Cerebral Dominance ◽  
Circle Of Willis ◽  
Detailed Knowledge ◽  
Differential Growth ◽  
Ischemic Attack ◽  
The Individual ◽  
The Right ◽  
The Brain

Abstract Background and aims: The cerebral circulation is constantly maintained by the anastomotic circle of Willis which is often anomalous in more than 50% of the normal adult brains. These anomalies increase the risk of the stroke and transient ischemic attack in older patients. Adequate blood flow through the circle of Willis is often necessary to prevent these ischemic infarctions. The anomalies of cerebral vessels are directly related to the differential growth of various parts of the brain. A detailed knowledge of the individual measurements of the cerebral arteries is useful to neurosurgeon in planning the shunt operations and in the choice of their patients. The present study is aimed to analyze the average dimensions of the vessels at the base of brain and an attempt to explain the common form of variations in terms of embryological development. Materials and methods: Fifty adult cadaveric brains were obtained from routine cadaveric dissections. The base of the brain with the circle of Willis was fixed in 10% formalin and preserved. The circle was analyzed for variations in the size, length and number of the component vessels and any asymmetry in the configuration. The dimensions of the vessels forming the circle were measured using graduated calipers. The observations were recorded and tabulated. Results: Asymmetry was observed in 10% to 36% of the circles in this study. Anomalies were more common in the posterior than in the anterior part of the circle. The posterior anomalies included hypoplastic vessels, absent vessels and embryonic derivation while anterior anomalies were predominantly of accessory vessels. Middle cerebral artery exhibited the least variations. In majority of the circles, left sided vessels were larger in diameter than the right. Conclusions: Variations are more common in the posterior than in the anterior part of the circle and on the right than on the left side of the brain. There was no correlation between the variations of circle of Willis of the right side and the left cerebral dominance. There seems to be no difference between races, concerning the anatomic variations of the brain circulation.

scholarly journals Anatomical variations of circle of Willis - a cadaveric study

2017 ◽  
Vol 4 (4) ◽  
pp. 1249 ◽  
Author(s):  
Ramanuj Singh ◽  
Ajay Babu Kannabathula ◽  
Himadri Sunam ◽  
Debajani Deka
Keyword(s):  
Cerebral Artery ◽  
Anterior Cerebral Artery ◽  
Anterior Part ◽  
Cerebral Arteries ◽  
Anatomical Variations ◽  
Circle Of Willis ◽  
Anterior Communicating Artery ◽  
Surgical Interventions ◽  
Collateral Channel ◽  
The Right

Background: The circle of Willis (CW) is a vascular network formed at the base of skull in the interpeduncular fossa. Its anterior part is formed by the anterior cerebral artery, from either side. Anterior communicating artery connects the right and left anterior cerebral arteries. Posteriorly, the basilar artery divides into right and left posterior cerebral arteries and each join to ipsilateral internal carotid artery through a posterior communicating artery. Anterior communicating artery and posterior communicating arteries are important component of circle of Willis, acts as collateral channel to stabilize blood flow. In the present study, anatomical variations in the circle of Willis were noted.Methods: 75 apparently normal formalin fixed brain specimens were collected from human cadavers. 55 Normal anatomical pattern and 20 variations of circle of Willis were studied. The Circles of Willis arteries were then colored, photographed, numbered and the abnormalities, if any, were noted.Results: Twenty variations were noted. The most common variation observed is in the anterior communicating artery followed by some other variations like the Posterior communicating arteries, Anterior cerebral artery and posterior cerebral artery (PCA) was found in 20 specimens.Conclusions: Knowledge on of variations in the formation of Circle of Willis, all surgical interventions should be preceded by angiography. Awareness of these anatomical variations is important in the neurovascular procedures.

scholarly journals Evolutionary Role of Epigenetics in Ischemic Stroke: A Review

2020 ◽  
Vol 11 (SPL4) ◽  
pp. 1616-1620
Author(s):  
Rohini Agrawal ◽  
Prashant Amale ◽  
Shilpa Deshpande ◽  
Manish Deshmukh ◽  
Priti Bhoyar ◽  
...  
Keyword(s):  
Blood Flow ◽  
Ischemic Stroke ◽  
Hemorrhagic Stroke ◽  
Neural Stem Progenitor Cells ◽  
Genetic Level ◽  
Flow Through ◽  
After Cancer ◽  
The Brain ◽  
Global Population

Stroke is a Central Nervous System (CNS) disorder which occurs due to the obstruction in the brain blood flow. Stroke is mainly of two types, such as ischemic and hemorrhagic stroke. Ischemic stroke (80%) caused due to obstruction of blood flow through Middle Cerebral Artery (MCA) and characterized by a decreased supply of oxygen and glucose to CNS. In comparison, Hemorrhagic stroke (20%) mainly occurs due to the rupturing of blood vessels. Epidemiologically, it is the common reason of death after cancer and affecting millions of global population. There are many risk factors such as hypertension; hypercholesterolemia etc. which can exaggerate the condition of stroke. Various conventional therapies like Antiplatelets, Thrombolytic are available, but, there is a need to obtain a therapeutic approach that can provide prevention as well as a cure for the stroke. So the present review is primarily focused on epigenetic approach for ischemic stroke by Endogenous Transplantation of Neural Stem/Progenitor Cells (NSPCs). This, in turn, will decrease the level of REST protein at the genetic level and enhance the activity of Na+-Ca+ exchanger activity and lowers the excitotoxicity.

scholarly journals Role of age-related alterations of the cerebral venous circulation in the pathogenesis of vascular cognitive impairment

2019 ◽  
Vol 316 (5) ◽  
pp. H1124-H1140 ◽  
Author(s):  
Gabor A. Fulop ◽  
Stefano Tarantini ◽  
Andriy Yabluchanskiy ◽  
Andrea Molnar ◽  
Calin I. Prodan ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Cerebral Arteries ◽  
Vascular Cognitive Impairment ◽  
Cerebral Veins ◽  
Older Individuals ◽  
Low Velocity ◽  
Venous Circulation ◽  
Age Related ◽  
The Brain

There has been an increasing appreciation of the role of vascular contributions to cognitive impairment and dementia (VCID) associated with old age. Strong preclinical and translational evidence links age-related dysfunction and structural alterations of the cerebral arteries, arterioles, and capillaries to the pathogenesis of many types of dementia in the elderly, including Alzheimer’s disease. The low-pressure, low-velocity, and large-volume venous circulation of the brain also plays critical roles in the maintenance of homeostasis in the central nervous system. Despite its physiological importance, the role of age-related alterations of the brain venous circulation in the pathogenesis of vascular cognitive impairment and dementia is much less understood. This overview discusses the role of cerebral veins in the pathogenesis of VCID. Pathophysiological consequences of age-related dysregulation of the cerebral venous circulation are explored, including blood-brain barrier disruption, neuroinflammation, exacerbation of neurodegeneration, development of cerebral microhemorrhages of venous origin, altered production of cerebrospinal fluid, impaired function of the glymphatics system, dysregulation of cerebral blood flow, and ischemic neuronal dysfunction and damage. Understanding the age-related functional and phenotypic alterations of the cerebral venous circulation is critical for developing new preventive, diagnostic, and therapeutic approaches to preserve brain health in older individuals.

Computational Assessment of the Relation Between Embolism Source and Embolus Distribution to the Circle of Willis for Improved Understanding of Stroke Etiology

2016 ◽  
Vol 138 (8) ◽  
Author(s):  
Debanjan Mukherjee ◽  
Neel D. Jani ◽  
Kartiga Selvaganesan ◽  
Christopher L. Weng ◽  
Shawn C. Shadden
Keyword(s):  
Cerebral Arteries ◽  
Embolic Stroke ◽  
Patient Specific ◽  
Complex Nature ◽  
Clear Understanding ◽  
Relative Distribution ◽  
Large Arteries ◽  
Stroke Etiology ◽  
Long Term Treatment ◽  
The Brain

Stroke caused by an embolism accounts for about a third of all stroke cases. Understanding the source and cause of the embolism is critical for diagnosis and long-term treatment of such stroke cases. The complex nature of the transport of an embolus within large arteries is a primary hindrance to a clear understanding of embolic stroke etiology. Recent advances in medical image-based computational hemodynamics modeling have rendered increasing utility to such techniques as a probe into the complex flow and transport phenomena in large arteries. In this work, we present a novel, patient-specific, computational framework for understanding embolic stroke etiology, by combining image-based hemodynamics with discrete particle dynamics and a sampling-based analysis. The framework allows us to explore the important question of how embolism source manifests itself in embolus distribution across the various major cerebral arteries. Our investigations illustrate prominent numerical evidence regarding (i) the size/inertia-dependent trends in embolus distribution to the brain; (ii) the relative distribution of cardiogenic versus aortogenic emboli among the anterior, middle, and posterior cerebral arteries; (iii) the left versus right brain preference in cardio-emboli and aortic-emboli transport; and (iv) the source–destination relationship for embolisms affecting the brain.

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