Time-dependent aspects of the flow in the carotid bifurcation: continuous DPIV and computational results

Cerebrovascular disease (stroke) and cerebral ischemia are a leading cause of mortality and morbidity. Approximately 80% of all strokes are caused by ischemia. Occlusion or stenosis in the internal carotid artery (ICA), which starts at the bifurcation of the common carotid artery (CCA), is the result of disease of the arterial wall. Complication by thrombosis or embolism is the most frequent cause of cerebral ischemia and infarction. Biofluid factors such as abnormal shear stresses and turbulence have been cited to promote these disorders. Continuous digital particle image velocimetry (CDPIV) is used to map the flow field of vascular model of the ICA and obtain its time and spectral signatures. Computational fluid dynamics (CFD) is used to calculate and validate the hemodynamic factors governing the flow field. Continuous sequences of resulting images are given as animated presentation of distensible carotid bifurcation model. High shear stress peaks and vortices are observed at the bifurcation heel. Flow reversal or separation is Reynolds number dependent. The flow profile and spectra were dependent on geometry and elasticity. The combination of CDPIV and CFD seems to be a powerful tool enabling complementary time dependent assessments of the demanding field of cerebrovascular disease.