Preliminary study on hemodynamics in human carotid bifurcation by computational fluid dynamics

Objective: To investigate the visualization and quantitation of hemodynamic variables at carotid artery bifurcation in vivo by combining computational fluid dynamics (CFD) and vascular imaging. Methods: A healthy volunteer underwent CT angiography of left carotid artery by SIEMENS multi-slice CT. Parameters of hemodynamics at this carotid bifurcation were calculated and visualized by combining vascular imaging post-processing and CFD. Results: (1) The average range of flow velocity was 0.04-0.36 m/s. A region of high velocity was seen at medial wall of internal carotid artery (ICA) and medial wall of external carotid artery (ECA), respectively. The largest contiguous region of low velocity occurred at the carotid bulb. (2)The average range of absolute pressure, static pressure and dynamic pressure was 100 266.70-101 615.90 Pa, -1058.34-290.88 Pa, and 6.12-553.25 Pa, respectively. (3) The average range of wall shear stress (WSS) at the bifurcation was 0.59-5.35 Pa. There was a large region of low WSS at carotid bulb and posterior wall of ICA, with the lowest value of 0.25 Pa. Also there was a small region of low WSS at anterior and lateral wall of ECA. Conclusion: CFD combined with vascular imaging can calculate and visualize the parameters of hemodynamics at carotid bifurcation in vivo individually. It is an interdisciplinary science of computer, radiology and hemodynamics and provides a new method to investigate the relationship of vascular geometry and flow condition with atherosclerotic pathological changes. (authors)