Pulsatile flow simulation in arterial vascular segments with intravascularultrasound images

Previous studies have indicated a correlation between local variation in wa ll shear stress in arterial blood flow and atheroma development. The purpos e of this study was to analyze the hemodynamics in vascular segments from m orphologically realistic three-dimensional (3D) reconstruction. and to comp are the computed wall shear stress in a compliant vascular segment model an d the corresponding rigid walled model. Cross-sectional images of the segme nts of femoral and carotid arteries in five Yucatan miniswine were obtained using intravascular ultrasound (IVUS) imaging and the segment geometry was reconstructed at different times in the cardiac cycle. The actual measured wall motion from the reconstruction was employed to specify the moving bou ndaries for simulation of physiological distensibility. Velocity profiles a nd wall shear stress were computed using unsteady computational fluid dynam ics analysis, The computed results revealed that the maximum wall shear str ess in the compliant model was approximately 4-17 percent less than that in the rigid model if the wall motion is larger than 10 percent. Our analysis demonstrates that inaccuracies due to inflow velocity profile can be minim ized by the extension of the model upstream. The phase angle between the di ameter change and wall shear is affected by the local changes in geometry o f the arteries. These simulations can be potentially used to analyze the ef fect of regional wall motion changes in the presence of atherosclerotic les ions on the local fluid dynamics and to correlate the same with subsequent growth of the lesions. (C) 2001 IPEM. Published by Elsevier Science Ltd. Al l rights reserved.