Computational Fluid–Structure Interactions in the Human Cerebrovascular System: Part 1—A Review of the Current Understanding of Cerebrovascular Biomechanics

Computational fluid–structure interaction (FSI) modeling is a technique used in engineering to understand the effect that fluid flow and surrounding structures have on one another. Used in the aerospace and turbine industries, when applied in the appropriate scenarios, the outcome of fluid–solid interaction analyses may yield more precise results than computational fluid dynamics or mechanical structural testing/analysis alone. For biological systems, such as the cerebrovascular system in humans, the inherent complexity of the system makes performing clinically accurate predictive computational modeling challenging. An isolated computational fluid dynamic analysis of the blood flow to predict cerebral aneurysm rupture or an isolated structural analysis of the cerebral aneurysm dome may be only part of the answer to predicting whether an aneurysm will rupture and over what time span. The variable pressures and flow rate of blood through vessels cause blood vessel walls to change shape, rebound, and move within the adjacent tissue. This rebounding movement, in turn, alters the flow pattern of blood. In pathologies such as cerebral aneurysms or cerebral arteriovenous malformations (AVMs) with unpredictable rupture profiles, these small interactions between blood flow and vessel distension may potentially explain the difference between a catastrophic hemorrhage and an entirely quiescent lesion. This two-part review evaluates (1) the current understanding of cerebrovascular fluid and structure mechanical properties and (2) the state of fluid–structure interaction models in the cerebrovascular systems. Additionally, as the cardiovascular FSI literature is much more extensive than the cerebrovascular literature, future potential studies that glean insight from that work are discussed.