The spatio-temporal variation of rat carotid artery bifurcation by ultrasound imaging

The evaluation of arterial wall motion and hemodynamics contribute to early diagnosis of carotid atherosclerosis. The low wall shear stress in the arteries is known to be related to the development of atherosclerosis. Ultrasound imaging with high temporal resolution provides real time observation of anatomy structure. Reconstruction of three-dimensional (3-D) geometry with temporal variation not only helps us to know the 3-D behavior of the arteries but also provides reliable geometrical information for numerical simulation to evaluate the wall shear stress (WSS) distribution. In present study, the 3D data set of carotid artery bifurcation (CAB) in three rat subjects was acquired using a high spatio-temporal resolution ultrasound imaging system, Vevo 770, with linear mechanical scanning. Total of 31 slices of cross-section image were stored for each subject. A scanline algorithm was implemented to radially scan the lumen area based on a pre-tracked seed point in polar coordinate. The boundary of lumen was segmented using a dynamic threshold filter with polynomial fitting. Finally, 3-D geometries of CAB during one cardiac cycle were constructed based on segmented lumen boundaries. This variation in 3-D could improve our understanding of arterial behavior and also provide reliable references for numerical simulation of hemodynamics.