Experimental Study On The Biomechanical Parameters Of Carotid Bifurcation Based On High-resolution Ultrasound Imaging

Cardiovascular disease(CVD)has become the most serious threat to human health,thus new methods are urgent to be developed for early diagnosis of CVD.More than 75 percents of the cardiovascular disease that cause disability or death is atherosclerosis.Atherosclerosis usually locates at very specific sites where the environment of biomechanics is complex,like the curved vessel and vascular bifurcation.Research shows that the biomechanics environment around vascular endothelial cell plays an important role on vascular remodeling and the formation of atherosclerosis.As the current atherosclerosis early diagnosis methods are all based on vascular structural and functional changes,this project proposes a noninvasive high-resolution ultrasound imaging method to study the changing pattern of biomechanical parameters(circumferential strain,distribution of flow field and stress phase angle)in carotid artery base on biomechanics.In this thesis,both in-vitro and in-vivo experiments are conducted to study the biomechanical parameters in carotid artery.This study provides a new method of early diagnosis of atherosclerosis.This thesis can be detailed as:Firstly,the changing pattern of biomechanical parameters of different locations in carotid artery are studied by using the experimental methods.Secondly,a noninvasive high-resolution imaging method that can simultaneously calculate the circumferential strain(CS)and wall shear stress(WSS)is proposed.To improve the calculation accuracy of complex flow field,a new algorithm is proposed based on the traditional template matching algorithm.Finally,the connection between biomechanical parameters and atherosclerosis are found and proved by analyzing the changing pattern of biomechanical parameters.The results of experiments show that the value of negative stress phase angle is largest in internal carotid and the value of WSS is minimum.The biomechanical environment in internal carotid can lead to the occurrence of atherosclerosis.The result identifies the role of biomechanical parameters in detection and localization of vascular lesions.