心肌灌注核磁共振图像定量分析

发布时间：2018-04-26 05:39

本文选题：核磁共振图像 + 心肌灌注　；参考：《上海交通大学》2014年硕士论文

【摘要】：随着生活节奏的不断加快，心脏疾病的发病率在近20年中不断增高，心血管疾病已成为死亡率最高的疾病之一。核磁共振技术的发展与成熟为心血管疾病的诊断和治疗提供了重要的影像依据，也使心肌灌注的定量分析成为可能，而针对心肌灌注核磁共振图像的研究对于指导心血管疾病的治疗和预后判断有重要意义。其中，心肌灌注核磁共振图像的定量分析，是计算机辅助心血管疾病诊断和预后的重要基础。心肌灌注核磁共振图像定量分析传统上采用的是半定量的方法，以心肌壁造影剂充盈速度曲线得到的若干参数作为分析对象，而没有考虑左心室中造影剂的充盈速度对于心肌壁造成的影响。因此，由于没有去除这些干扰因素的影响，获取的参数缺乏可靠的参照量对比，参数与血流量之间的关系都是通过经验观测得到，进行量化分析不准确。为了提高准确性，本文采用绝对定量分析方法，该方法的理论基础是中心容积定律。该方法将左心室心肌灌注过程作为一个动态系统考虑，以左心室内造影剂的灌注速度作为输人，左心室心肌灌注残留造影剂量作为输出，左心室心肌灌注动态过程的数学模型作为需要测定或辨识的系统。首先对临床采集的心肌灌注核磁共振图像进行插值放大。然后进行图像配准，并采用平均滤波的方法对图像的伪影和噪声进行处理，获得心肌灌注信号强度曲线以及左心室灌注信号强度曲线。随后将灌注曲线进行解耦，建立基于相关数学模型的传递函数，也称为剩余函数，并利用非线性优化方法对数学模型进行参数辨识。剩余函数的拟合又是绝对定量分析的关键，有人采用样条模型，可以对剩余函数进行很好的拟合，但是样条模型的参数太多，不容易对参数进行比较和分析。也有人使用Fermi模型来拟合剩余函数，但是参数不具有实际的物理意义。本文采用了指数模型对剩余函数进行拟合，指数模型带有两个参数，不但减少了参数的数量，而且模型参数具有更多的物理意义。本文对指数模型参数进行了分析和比较，通过和传统的半定量方法的对比分析了指数模型的参数稳定性。本文也通过比较正常人和非正常人之间的参数分析了基于指数模型定量方法对于临床辅助诊断的意义。实验证明，经本文提出的方法具有良好的可靠性，能为医生判断心肌的状态提供依据。在临床诊断和治疗中有临床应用价值。本文根据临床中对心肌灌注核磁共振图像分析的需求，设计了相关定量分析软件。软件的输入为临床采集的心肌灌注核磁共振数据文件，输出为定量分析参数的图形界面。软件主要由五个模块组成：DICOM文件解析，，图像配准，图像处理，参数辨识，用户界面等。软件设计框架基于MFC，采用C++和MATLAB混合编程的方法，以眼图和数据相结合的直观形式为医生提供病人诊断信息。
[Abstract]:With the rapid pace of life, the incidence of heart disease has been increasing in the past 20 years, and cardiovascular disease has become one of the highest mortality diseases. The development and maturity of nuclear magnetic resonance technology provide important imaging basis for the diagnosis and treatment of cardiovascular disease, and make the quantitative analysis of myocardial perfusion possible. The study of myocardial perfusion MRI is of great significance in guiding the treatment and prognosis of cardiovascular diseases. The quantitative analysis of myocardial perfusion MRI is an important basis for computer aided diagnosis and prognosis of cardiovascular diseases. The quantitative analysis of myocardial perfusion MRI is a semi-quantitative method, and some parameters obtained from the filling velocity curve of myocardial contrast medium are taken as the analysis object. The effect of the filling velocity of contrast agent on myocardial wall was not taken into account. Therefore, because the influence of these interference factors is not removed, the obtained parameters are lack of reliable reference quantity contrast, the relationship between parameters and blood flow is obtained through empirical observation, and the quantitative analysis is not accurate. In order to improve the accuracy, an absolute quantitative analysis method is adopted, which is based on the central volume law. In this method, the left ventricular perfusion process is considered as a dynamic system, the perfusion rate of the left ventricular contrast agent is taken as the infusion rate, and the residual contrast agent quantity of the left ventricular perfusion is taken as the output. A mathematical model of the left ventricular perfusion process is used as a system to be measured or identified. Firstly, the myocardial perfusion MRI images collected by clinic were interpolated and amplified. Then the image registration is carried out, and the artifact and noise of the image are processed by the average filtering method, and the myocardial perfusion signal intensity curve and the left ventricular perfusion signal intensity curve are obtained. Then the perfusion curve is decoupled, and the transfer function based on the correlation mathematical model, also called residual function, is established. The nonlinear optimization method is used to identify the parameters of the mathematical model. The fitting of residual function is the key of absolute quantitative analysis. Some people can fit the residual function well by using spline model, but the parameters of spline model are too many to be compared and analyzed easily. Fermi model is also used to fit the residual function, but the parameters have no practical physical significance. In this paper, the exponential model is used to fit the residual function. The exponential model has two parameters, which not only reduces the number of parameters, but also has more physical significance. In this paper, the parameters of exponential model are analyzed and compared, and the parameter stability of exponential model is analyzed by comparing with the traditional semi-quantitative method. The significance of quantitative method based on exponential model for clinical diagnosis was also analyzed by comparing the parameters between normal and abnormal people. The experimental results show that the proposed method has good reliability and can provide a basis for doctors to judge the state of myocardium. It has clinical application value in clinical diagnosis and treatment. According to the requirement of myocardial perfusion MRI image analysis in clinic, a quantitative analysis software was designed. The input of the software is clinical myocardial perfusion nuclear magnetic resonance data file, and the output is the graphical interface of quantitative analysis parameters. The software consists of five modules: DICOM file analysis, image registration, image processing, parameter identification, user interface and so on. The software design framework is based on MFCs and adopts the method of C and MATLAB mixed programming to provide the diagnosis information for the doctor by the visual form of the combination of eye diagram and data.
【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TP391.41;R445.2

【参考文献】