Biomechanical Modeling of Cerebral Aneurysm Progression to Estimate Rupture Risk

Abstract

A cerebral aneurysm is a medical condition described as the bulging out of the cerebral artery under adverse pressure conditions. Patients with such medical conditions have a mortality of 20% and additional morbidity of 30–40% due to aneurysm rupture. The currently used imaging tools such as MRI and CT scans only provide geometrical information of the aneurysm and not the rupture risk associated with the progression of the aneurysm. A novel computational modeling framework was developed to model aneurysm progression and evaluate the stress distribution under varying pressure loading conditions to bridge this gap. Image segmentation was used to segment two middle cerebral arteries (MCA) and reconstructed to design aneurysm models at vulnerable sites for aneurysm progression simulation. Five aneurysm sizes and two different wall thicknesses were modeled to simulate different stages of aneurysm progression. Three pressures (i.e., diastolic, systolic, and hypertensive) were adopted to mimic the realistic pressure loading scenario for the middle cerebral arteries, and the stress distributions across all the models were estimated to understand the rupture risk. It was observed that the induced stresses in the aneurysm walls increased with an increase in the aneurysm diameter and blood pressure. Additionally, an aneurysm with a large diameter and thin walls exhibited a high risk of rupture, especially at high blood pressures. The reported results are anticipated to help medical practitioners predict rupture risks with known imaging-based aneurysm sizes and make timely decisions for such aneurysm conditions.