Effects of aspect ratio, wall thickness and hypertension in the patient-specific computational modeling of cerebral aneurysms using fluid-structure interaction analysis

Abstract

Intracranial aneurysm is a pathological dilatation of the cerebral artery which can lead to high mortality rate upon rupture. The aspect ratio (AR) of an aneurysm, being the ratio of the height to neck width, is an important factor in estimating the likelihood of aneurysm rupture in clinical practice. AR will generally increase while the aneurysm grows. Clinical observations over the years show that aneurysms with larger AR usually exhibit higher rupture risk. The goal of the current study is to conduct Fluid-Structure Interaction (FSI) analyses to provide quantitative estimates on the importance of AR, wall thickness (tw) and hypertension. The effects of varying AR and tw on the hemodynamics, wall stress and displacement will be studied based on patient-specific models. Both sidewall and bifurcation aneurysms are investigated. There is a significant increase in the wall stress at the aneurysmal dome (the location in an aneurysm where rupture is commonly observed clinically) when the AR increases and tw decreases due to the aneurysm growth process. Furthermore, these investigations are repeated for patients with hypertension (high blood pressure) conditions. The increase in the wall stress due to hypertension for models with higher ARs is more dramatic. The clinically observed feature of higher rupture risk of aneurysms with larger AR is thus supported quantitatively.

Keywords

• intracranial aneurysms
• fluid-structure interaction
• fsi
• aspect ratio
• wall thickness
• hypertension