Computational Flow Dynamics Study in Severe Carotid Bulb Stenosis with Ulceration

Purpose: Computational fluid dynamics (CFD) applications for atherosclerotic carotid stenosis have not been widely used due to limited resolution in the severely stenotic lumen as well as small flow dimension in the stenotic channel. Materials and Methods: CT data in DICOM format was transformed into 3 dimensional (3D) CFD model of carotid bifurcation. For computational analysis of blood flow in stenosis, commercial finite element software (ADINA Ver. 8.5) was used. The blood flow was assumed to be laminar, viscous, Newtonian, and incompressible. The distribution of wall shear stress (WSS), peak velocity and pressure across the average systolic and diastolic blood pressures permitted construction of a contour map of the velocity in each cardiac cycle. Results: Computer simulation of WSS, flow velocity and wall pressure could be demonstrated three dimensionally according to flow vs. time dimension. Such flow model was correlated with angiographic finding related to maximum degree of stenosis associated with ulceration. Combination of WSS map and catheter angiogram indicated that the highest WSS corresponded to the most severely stenotic segment at systolic phase, whereas ulceration, which is the weakest point of the plaque, appeared at the downstream side of the carotid bulb stenosis. Conclusion: Our preliminary study revealed that 3D CFD analysis in carotid stenosis was feasible from CT angiography source image and could reveal WSS, flow velocity and wall pressure in the severe carotid bulb stenosis with ulceration. Further CFD analysis is warranted to apply such hemodynamic information to the atherosclerotic lesion in the more practical way.