Review of CFD Based Simulations to Study the Hemodynamics of Cerebral Aneurysms

The human circulatory system facilitates supply of oxygen and nutrients to all the tissues in the body. This system consists of a net-work of closed-compliant tubes (the aorta, arteries, arterioles, capillaries, venules and veins, etc) of various sizes and lengths, start and terminate at the chambers of the heart. However, continuous flow of blood through these vessels is the genesis for the development of a number of circulation-related medical emergencies such as, myocardial infarction, stroke etc. Most problems in cerebral circulatory disorders are due to formation of constrictions, bulges, blockages or leakages. Correspondingly, the blood vessels are subjected to stenosis, aneurysms, stroke, brain hemorrhage etc. Computational Fluid Dynamics (CFD) engineers can employ mathematical models to analyze a number of what-if type scenarios of clinical interest, for patient-specific conditions. Present study covers cerebrovascular disorders such as Moyamoya Angiopathy (MMA), Arteriovenous malformations (AVM), Stroke, Stenosis and aneurysms in a broader sense, as the CFD tools are similar for all these flow problems. Literature is replete with modeling tools, methods for supporting clinical decisions prior to surgical/ endovascular intervention. Typically, CFD-based modeling starts with a radiological scan to identify the underlying disease-specific condition to segment the region of interest. Identified geometry is meshed and simulated with the aid of CFD-based solvers to develop hemodynamic parameters of clinical interest. Present study reviews the state-of-the-art regarding such tools and analyzes the modeling steps involved. This review is limited to the cerebrovascular disorders and the modelling of aneurysm rupture-risk prediction tools of importance to clinical decision making. In this review, a brief of CFD analysis of various clinical management options such as clipping, coiling, bypass etc are presented. Although most analysis is based on clinical parameters coupled with radiological features on a population cohort, CFD based tools are gradually gaining prominence. Development of reliable tools with and without fluid–structure interaction are central to providing confidence to the clinicians. Understanding blood flow and enabling necessary perfusion to various parts of the body is important to our healthy living and survival.