Effect of Moderate Stenosis on the Upstream and Downstream Flow Patterns in the Internal Carotid Artery—An in vitro Investigation

Abstract

Abstract. Narrowing of the internal carotid artery (ICA), known as stenosis, can significantly alter normal blood flow and increase the likelihood of cerebrovascular complications such as ischemic stroke. This study presents an in vitro investigation of flow dynamics in a stenosed ICA. A blood-mimicking fluid (BMF) was circulated through the model, allowing for flow behavior similar to physiological conditions. Flow visualization was achieved using particle streak velocimetry (PSV), a noninvasive optical measurement technique capable of capturing the detailed velocity fields. The axial velocity revealed an interesting phenomenon: the velocity profile became smoother and tended toward a more parabolic shape compared to the nonstenotic case, where the peak typically shifts toward the inner curvature region. However, this asymmetry became less pronounced within the stenotic section. The presence of stenosis introduces an opposing curvature, effectively neutralizing the asymmetric flow distribution. Furthermore, the transverse velocity component (v) was plotted along the axial direction (x) to assess secondary flow behavior. The resulting v versus x plot exhibited clear indications of flow disturbances and recirculation zones downstream of the constriction. These findings demonstrate how stenosis modifies the flow patterns within the ICA, potentially contributing to adverse clinical outcomes. The experimental approach using a blood-mimicking fluid and PSV enables a detailed understanding of hemodynamic behavior in stenosed arteries. Such insights are valuable for advancing diagnostic methods and improving treatment planning in vascular diseases.