基于同步辐射的小鼠冠状动脉在位造影成像和图像增强研究

发布时间：2018-01-26 06:49

本文关键词： 同步辐射冠状动脉造影小鼠模型在位图像增强图像减影相关系数数学形态学呼吸周期心脏搏动伪周期　出处：《上海交通大学》2013年博士论文　论文类型：学位论文

【摘要】：冠状动脉是心肌细胞的供血动脉，对冠状动脉的深入研究，有助于相关心脏疾病或者心肌病变的正确诊断。小鼠由于其易于制作各种疾病模型的特点，广泛运用于心脏疾病的病理研究。但是目前的小鼠心脏疾病研究缺乏一种直观的影像学方法，这是由于常规的影像学方法分辨率较低，很难获得有价值的图像。近年来发展起来的同步辐射成像技术因其单色性好、高准直性等特点[1]，，能够获得高时间分辨率和高空间分辨率的图像，从而使得小鼠的在位冠状动脉造影成像成为可能。本实验建立了一整套完整的小鼠冠状动脉成像和图像预处理方法，从而为心脏和冠脉疾病的病理和药理研究提供一种有效的手段。主要内容如下： 1、确立完整的同步辐射小鼠在位冠状动脉成像的参数体系。在模拟实验中模拟血管造影成像，确定在上海同步辐射装置下的最佳的成像能量为33-34keV，探测器空间分辨率为26μm、时间分辨率至少每秒10帧，造影剂采用与清水3：1混合的医用碘帕醇溶液。造影剂注射采用脉冲式注射的方法，瞬时注射速度为12ml/m。 2、确定正常小鼠冠状动脉成像模型采用颈动脉插管的方法注射造影剂，并在设定好的最佳参数范围内进行在位成像，确认实验的可重复性并规范实验操作步骤。 3、提出一整套图像预处理方法来改善成像结果，消除呼吸运动导致的肋骨等运动背景的干扰。算法首先利用灰度均值对冠脉序列图像进行灰度修正，消除变化的同步辐射光通量对图像整体灰度值的影响；然后利用图像肋骨区域的相关系数矩阵来选择最匹配的背景帧，实现对冠脉序列的减影增强；接着利用数学形态学的方法对减影后的图像进行图像增强，消除结构尺寸大于冠状动脉直径的背景结构，增强冠脉血管的对比度；最后利用灰度共生矩阵分析增强前后图像的纹理特征，证明算法消除结构噪声的有效性。 4、对增强后的冠脉图像进行血管区域提取，进行呼吸周期和心脏搏动伪周期的估计和分析，弥补由于实验条件无法进行实时呼吸和心跳监测造成的成像数据缺陷；并通过统计的方法验证实验所采用的减影和图像增强算法的有效性。
[Abstract]:Coronary artery is the blood supply artery of cardiomyocytes. The in-depth study of coronary artery is helpful to the correct diagnosis of related heart disease or cardiomyopathy. It is widely used in the pathological study of heart disease. However, the present study of heart disease in mice lacks an intuitive imaging method, which is due to the low resolution of conventional imaging methods. It is difficult to obtain valuable images. Synchrotron radiation imaging technology developed in recent years is characterized by its good monochromatic and high collimation. [1] it is possible to obtain images with high temporal resolution and high spatial resolution. In order to make in situ coronary angiography possible in mice, a complete set of coronary artery imaging and image preprocessing methods were established in this experiment. Thus providing an effective means for the pathological and pharmacological study of heart and coronary artery diseases. The main contents are as follows: 1. Establish a complete parameter system of synchrotron radiation in vivo coronary artery imaging in mice. The optimal imaging energy under the Shanghai Synchrotron radiation device is determined to be 33-34keV, the spatial resolution of the detector is 26 渭 m, and the temporal resolution is at least 10 frames per second. The contrast medium was mixed with 3: 1 of clear water, and the contrast medium was injected with pulse injection at an instantaneous rate of 12 ml / m. 2. The coronary artery imaging model of normal mice was established by carotid artery catheterization. The contrast medium was injected into the coronary artery, and the in-situ imaging was performed within the set optimal parameters. Confirm the repeatability of the experiment and standardize the procedure. 3. A whole set of image preprocessing methods is proposed to improve the imaging results and eliminate the interference of the moving background such as the rib caused by respiratory movement. Firstly, the gray level of the coronary artery sequence image is corrected by the gray mean. Eliminating the influence of varying synchrotron radiation luminous flux on the overall gray value of the image; Then the correlation-coefficient matrix of the frame region is used to select the most matched background frame to realize the subtraction enhancement of coronary artery sequence. Then the image is enhanced by mathematical morphology to eliminate the background structure whose size is larger than the diameter of coronary artery and enhance the contrast of coronary artery. Finally, the texture features of the images before and after enhancement are analyzed by using the gray level co-occurrence matrix, which proves that the algorithm is effective in eliminating structural noise. 4Vascular region was extracted from the enhanced coronary artery image, and the respiratory cycle and the pseudo-cycle of heart pulsation were estimated and analyzed. Make up for the imperfections of imaging data caused by the inability of real-time breathing and heartbeat monitoring under experimental conditions; The effectiveness of the subtraction and image enhancement algorithms used in the experiment is verified by statistical method.
【学位授予单位】：上海交通大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：R816.2;R541.4

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