Abstract
In this paper, a numerical estimation of wall shear stress (WSS) and study on hemodynamic pattern in carotid artery (CA) near the bifurcation region with dynamic growth of aneurysm using computational fluid dynamics (CFD) for making early clinical decision is presented. Aneurysm in the carotid artery affects the blood supply to brain and if it is untreated at early stage may lead to sudden death. Computed tomography images of four different cases of stroke subjects scanned of 600 slices with 1 mm resolution with neighbouring layers from neck to head are considered for this study. Numerically a CA with bifurcation region is developed from these images and aneurysm is and allowed to grow dynamically from 10 to 20 mm. WSS and hemodynamic pattern is estimated numerically using Ansys platform at various region of interest in both rigid and compliant wall conditions. The arterial wall thinning was analytically estimated using thick cylinder theory to estimate the increase in aneurysm under various stress conditions (rest and exercise conditions). The findings show that WSS is found to reduce at the aneurysm region with a corresponding strong vortex pattern. Thus, the vortex pattern could be the cause of tissue damage and thinning rather than WSS. The corresponding increase in velocity gradient at the bifurcation region is also captured. This high gradient is the cause for higher WSS at the bifurcation region which is a possible cause for the formation of plaque and arteriosclerosis. It is interesting to note that the WSS did not change drastically for 10 and 15 mm aneurysm but a large change was seen from normal to 10 and 15-20 mm respectively. This study provides a better clinical insight on the effect of aneurysm in CA bifurcation region using a systematic approach to numerical modelling compared to traditional imaging modalities. It can be used as an adjunct tool for physicians and surgeons for planning necessary clinical interventions.