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

Abstract

We 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.

Anatomical variations of the circle of Willis and their prevalence, with a focus on the posterior communicating artery: A literature review and meta‐analysis

“…Being familiar with the most common CoW variations and their prevalence can be of vital importance to clinicians. Many authors have suggested an increased risk of ischemic stroke in the presence of CoW variations (Chuang, Liu, Pan, & Lin, 2008; Hoksbergen et al, 2003; Mukherjee, Jani, Narvid, & Shadden, 2018). Chuang et al (2008), for example, highlight that hypoplasia of the PComA is associated with an increased risk of infarction, particularly in the thalamic region.…”

“…Mukherjee et al (2018) suggest that variant CoW anatomy can have an impact on the trajectory of microemboli, and hence lead to infarctions in distal, more unusual areas of the brain. Therefore, being aware of variations and their frequency can help us understand atypical stroke patterns, and predict their likelihood.…”

State-of-the-Art Computational Models of Circle of Willis With Physiological Applications: A Review

“…Furthermore, Mukherjee et al divided the embolism process into three independent steps, and estimated the risks of embolism from a probabilistic view using FSI simulation (Fig.4a) [75]. They applied the FSI model in 24 cases and concluded that anatomical variations of CoW significantly influenced embolus distribution to the six major cerebral arteries while MCA territory was least sensitive to the influence of anatomical variations [76].…”

Efficiency of Gymnema sylvestre‑derived gymnemic acid on the restoration and improvement of brain vascular characteristics in diabetic rats

“…The ICA supplies oxygenated blood to most midline portions of the frontal lobe and superior medial parietal lobe. It is the most important blood supply of the cerebral circulation from the circle of Willis (5). The MCA receives 80% of the carotid blood flow, whereas the ACA receives 20%.…”