| Cardiovascular disease is one of the most serious disease to human life and health, having a high rising trend year by year. The costs for the treatment is very huge, which had brought heavy burden to the country, social and the patient’s family. We have known that cardiovascular disease and aging directly affect the morphology and mechanical properties of cardiovascular system. Even though, the researchers have made obvious imaging progress of disease patho-physiology at home and abroad for decades. However, the current observation methods cannot satisfy the requirement of clinical diagnosis. With the emergence of new technology and the progress of technology, more and more interdisciplinary have made a contribution to the research of cardiovascular disease, these subjects will provide the basis to have a new breakthrough in the future.Actually the cardiovascular system can be considered as a mechanical system with the core of the heart, the working mechanism of heart is similar to the principle of pump which has a very close relationship to fluid mechanics. In recent study, biomedical researchers have put forward the application of the mechanics model of cardiovascular function on the diagnosis and treatment will have a high potential. Closely combining with the clinical application and the theory of fluid mechanics, flow field testing and medical imaging technology (such as CT, MRI, ultrasound), the cardiovascular biomechanics model and the individual operation plan established based on the clinical cases(image) to obtain the interested information and explain some physical phenomena by the model. The analysis method will provide more reference in clinical field.At present, the diastolic heart failure (DHF) possessed higher ratio in diseases of the cardiovascular system, accounted for30%～74%of the total number of heart failure. DHF with normal ejection fraction, considered to be a consequence of diastolic dysfunction, is a clinical syndrome that has reached epidemic proportions. However, the awareness of DHF is not enough, some divergence on the pathological mechanism of the disease is still exist. Because of lacking a perfect diagnostic method and criteria, the diagnosis and treatment of DHF patients is difficult. Abnormal diastolic function always accompanied with the stiffness changes of LV wall. The myocardial of focal fibrosis can make the LV wall difficult to relax. European society of cardiology working group has formulated the diagnostic criteria of DHF which including the LV wall stiffness. Now, the evaluation method of the diastolic function include measuring the blood flow spectrum by Doppler, isovolumetric relaxation time, radionuclide blood pool imaging methods and interventional cardiac catheter that collecting the LV pressure-volume curve within the entire cardiac cycle to measure the change the of press and volume(dP/dV). The current methods are mostly from the angle of the individual observation, that still have some disadvantages. Such as it is not accurate for the measurement of the LV chamber volume or having a trauma to the body.This paper presents a new modeling method about the heart function based on echocardiography imaging which having the characteristics of on traumatic, high frame frequency, and in real-time. Firstly, the image of58healthy adults and17patients with LVH were collected. Secondly, the boundary of E-wave was selected though the program of Matlab and fit the E-wave by mathematical equation. Thirdly, the P-V curve (press-volume) combining the hydrodynamic theory was used to,, derive the result (K) of LV wall stiffness finally.The computed value of K of healthy adults and LVH patient through the model, and made a statistics of the value of K and other ultrasound, clinical parameters by SPSS18.0.The results showed the model is rational, and the value of K is sensitive. The correlation analysis of the normal control group showed, the value of K had positive correlation with the peak velocity of E wave, and negatively correlation with DT (the deceleration time) and IVRT (isovolimetric relaxation time). The correlation analysis of the LVH group showed, the value of K had significantly negative correlation with c, IVRT and DT. These results have a high consistency to the known theory. The model could make up the disadvantage of the traditional method and provide a new direction for the study of the cardiovascular system.Another task of this paper was exploring the method of creating the finite element model and calculated the flow field of heart by computer. By the program of Matlab accessed the outline of the LV wall and mitral valve data from the gray-scale images of apex four-chamber view which obtained by the echocardiographic technique. Selected the ICEM CFD software to mesh and Fluent software to simulate. The results showed the flow field simulated by finite element model was reasonable by contrasting to the results of LV flow field visualization technology based the optical flow method. And we also contrasted the flow field of healthy adults and dilated cardiomyopathy to find the specificity.The results showed the shape of LV from the LVH patients was ellipsoidal. The velocity in the LV of dilated cardiomyopathy was lower and the distribution of the velocity is disordered to the normal adults. The position of vortex and blood flow mixing area didn’t not agree between the LVH patients and normal adults.The research in this paper is mainly based on the echocardiographic technology, all the work on heart function model will provide some new reference for the clinical diagnosis. |
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