Assessment Of The Severity Of Mitral Regurgtitation With Doppler Echocardiography

Mitral valve disorder is one of the most common diseases of the heart. Mitral regurgitation (MR) is usually the result of valvular degeneration, and will lead to body blood supply insufficiency. As the development of up-to-date medical techniques, the ratio of operations in valvular repair and valvular replacement has been largely improved. Accurate method is critically important in assessing the degree of mitral regurgitation to set down the corresponding treatment method. Echocardiography is the most common non-invasive diagnostic tool for the visualization of intracardiac blood flow, and it is easy to operate, and with low cost. The advent of color Doppler flow imaging substantially enhanced the clinical diagnosis of heart of mitral regurgitation severity. According to this technique, many mitral regurgitation severity evaluation methods were developed. And it improved the accuracy of mitral regurgitation diagnosis. Although numerous echocardiographic techniques, both qualitative and semi-quantitative, have been developed,no single precise method is routinely used as a "reference standard"to determine the severity of mitral regurgitation. In this thesis, quantitative evaluation method based on 2D and 3D real-time ultrasonic Doppler imaging, for the severity of MR is explored and investigated through clinic experiment.. First, through clinic experiments,we study the quantitative evaluation methods for the severity of MR based on 2D color Doppler imaging using jet area(射流面积), proximal isovelocity surface area (PISA) algorithm and VC width. The experiment result shows that, the effective regurgitant orifice area(EROA)of MR can be calculated with PISA algorithm, and then the value of regurgitation volume (RV) can be calculated further. This method has good correlation with the severity of mitral regurgitation. It is practical to grade the severity of MR, but difficult for the measurement of the mitral eccentric regurgitation. Second, we explore the method to evaluate eccentric MR. A modified PISA algorithm corrected with turbulent intensity and regurgitation angle is proposed. Corresponding experiment result shows that the modified method is more precise in the grading of eccentric regurgitation. Further, an integrated index was proposed, which is integrated with six parameters and can be used to grade the severity in the case of eccentric MR. Finally, we study the method for the evaluation of MR based on real-time 3D color Doppler flow image technique. After collecting the clinic images, we use TomTec workstation to measure the parameters of MR. The result suggests the method based 3D real-time imaging has a good correlation with the result based on 2D imaging, and is more accurate.