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BACKGROUND: Cervical rotation manipulation is a non-surgical method of cervical spondylosis, showing significant treatment efficacy. But the safety for patients with carotid artery atherosclerosis remains obscure. OBJECTIVE: To analyze the hemodynamic changes of atherosclerotic carotid arteries treated by cervical rotatory manipulation, and to explore the effect of cervical rotatory manipulation on the hemodynamics of atherosclerotic plaque. METHODS: Eight cases of stenosis of ramification of the carotid artery with plaque on MRI. The hemodynamic model of carotid artery atherosclerosis was established, assigned with general boundary conditions and simulated the cervical stretch during cervical rotatory manipulation. All models were grouped and stretched into 0％ (control group), 7％ and 16％ stretch to simulate the hemodynamic changes of atherosclerotic plaque. The hemodynamic parameters, including average wall shear stress, the maximum wall shear stress, the average maximum wall shear stress, the blood velocity of the plaque, and blood flow vectorgraph were compared among groups. RESULTS AND CONCLUSION: (1) All hemodynamic parameters had no significant differences between 7％ stretch and control groups (P＞ 0.05). Compared with the control group, the wall shear stress, the maximum wall shear stress, and the maximum wall shear stress in the 16％ stretch group were significantly increased (P ＜ 0.05), and other indexes showed no significant differences. (2) In summary, different stretches by cervical rotatory manipulation possess different effects on plaque, and a 16％ stretch may affect the hemodynamics of plaque.
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BACKGROUND:Exploration on nonlinear acoustic response of the contrast agent microbubble contained in microvessel under ultrasound excitation is of great significance to maximizing ultrasonic energy deposition, promoting the development of quantitative imaging algorithm, revealing the damage mechanism or evaluating the targeted therapy, and overcoming the limitations of the traditional methods that are mainly used in large-size vessels, and measuring microvessel elasticity. OBJECTIVE:To build a microvessel containing an ultrasound microbubble, revealing the internal mechanism among ultrasound, microbubble, blood flow and microvessel. METHODS:Based on the finite element analysis and the lumped parameter model, three-dimensional microvessel containing microbubble model was built and simulated on Comsol Multiphysics 4.4 platform. RESULTS AND CONCLUSION:Microbubble exhibited slower radial motion compared with axial motion due to vascular wal limitation, but maximum displacement and stress were found near the microbubble center because of the oscil ation coupling of the microbubble with the vascular wal . Under the same ultrasound pressure, the excitation frequency increased, accompanied by decreased and stabilized microvessl constriction and dilation;under the same frequency, with the enhancement of ultrasound pressure, the local microbubble oscil ation lasted longer. With the increase of Young’s modulus of the microvessel wal , the frequency of microbubble oscil ation was reduced, while the amplitude increased. Al these findings indicate that the frequency of microbubble oscil ation increased with the reduction of microvessel size, while its amplitude decreased. The frequency of microbubble oscil ation increased with the enhancement of ultrasound excitation, while the amplitude decreased. On the contrary, ultrasound pressure affected the dynamic characteristics of microbubble and microvessel. In particular, it was the first to demonstrate that the elasticity of microvessel has approximate linear positive correlation with the amplitude of microbubble oscil ation, which reveals the relationship between microvessel elasticity and microbubble response so as to provide theoretical basis for indirect measurement of microvessel elasticity.
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There are the descriptions on the development of domestic and international biological systems' modeling and simulation as well as the importance of course for undergraduates. The curriculum structure is discussed about the basic knowledge of modeling and simulation, traditional methods of modeling and simulation on biomedical engineering indus- tries and academic fields, visual modeling and simulation of blood circulatory system and model analysis of biological sta- tistical information, etc. On the basis of teaching experience, the method how to combine curriculum structure and scien- tific research field is explored, and one pattern is provided that could induce undergraduates to as soon as possible study science and research on professional knowledge for the biomedical engineering undergraduate courses. It is an inevitable trend of combination between curriculum and scientific research to develop the construction of our country undergraduate courses.