心血管冠状动脉循环包括主动脉循环和心肌微循环。相关研究证明，冠状动脉疾病不但与主动脉阻塞有关，而且与心肌微循环供血障碍有关。同时，心肌微循环结构显影对诸多心血管疾病的研究与临床诊疗具有重大意义。目前，尚无可靠的无创性影像技术能够对活体心肌微循环的结构进行显影，而这也是当前急需解决的临床技术难题。如果能对活体心肌微循环的结构进行可靠、无创地成像，则能更快更准确地找到冠状动脉疾病的诱因，极大地减少病人的痛苦和医疗风险。超声成像以其安全、无创、实时可监测等优点有着不可替代的技术优势和使用价值，一直是心血管成像领域的研究热点。本文对高分辨率超声超谐波心肌微血管成像方法展开了深入研究，为其应用于活体心肌微循环结构成像提供技术参考。
苹果来电闪光灯怎么设置
针对心肌微血管的特点，对超声超谐波心肌微血管成像方法进行了研究。该方法中，微泡造影剂作为血管的示踪剂，其随血液循环会充满整个心肌微血管。当低频超声阵元发射低频超声与相应尺寸的微泡产生共振时，由于非线性效应反射的超声波中会含有高次或超高次谐波成分，这些谐波成分携带着作用区域内血管的形貌信息，其会被高频超声阵元采集用来进行成像。该方法可增强心肌微循管图像的对比度和清晰度，为心血管疾病的诊疗提供良好的基础。
对超声超谐波心肌微血管成像所需软硬件技术进行了研究。在硬件方面，本文设计了适用于超声超谐波心肌微血管成像的超声发射电路与接收电路，完成了5MHz超声的高效发射和包含30MHz微弱谐波成分的回波信号的低噪声放大与采集。同时还对系统中出现的共模噪声来源进行了理论分析，并给出了解决办法，成功实现了共模噪声的有效抑制。在软件方面，本文研究和分析了超声超谐波成像系统中涉及的
一些信号处理算法，如数字滤波器设计、包络检测等，成功实现了超谐波信号的有效提取。
对超声超谐波成像平台进行了设计，进行了仿体微血管半实物仿真，对内径110μm的仿体微血管进行了三维成像，轴向分辨率可达300μm，横向分辨率可达100μm，表明超声超谐波心肌微血管成像方法具有高分辨率成像能力。
关键词：超声超谐波成像心肌微血管包络检测共模噪声抑制
Cardiovascular coronary circulation consists of aortic circulation and myocardial microcirculation. Some rearch indicates that coronary artery dia is not only caud by aortic obstruction, but also related to myocardial microcirculation blood supply disorder. The angiography of myocardial microcirculation structure is crucially significant for the experimental rearch, as well as clinical diagnosis and treatment of many cardiovascular dias. At prent, there is no reliable non-invasive imaging technology to visualize the structure of living myocardial microcirculation, which is also a clinical technical problem that needs to be solved urgently. Reliable, non-invasive imaging of the living myocardium microcirculation structure can help the diagnosis of coronary artery dia quickly and accurately, greatly reducing the patient's pain and medical risks. Ultrasound imaging has irreplaceable technical advantages and application values becau it is safe, non-invasive and real-ti
me. It has always been a rearch hotspot in the field of cardiovascular imaging. In this paper, the high-resolution ultrasound superharmonic imaging technology on myocardial microvascular is rearched in depth, and it provides a technical reference for its application to the imaging of living myocardial microcirculation.
Taking the feature of myocardial microcirculation into consideration, this paper rearched the method of ultrasound superharmonic myocardial microvascular imaging. In this method, microbubble contrast agent is a tracer of blood vesls, which will fill the whole myocardial microvesls with blood circulation. When low frequency array elements emit low frequency ultrasound, it will cau the corresponding size of microbubbles to resonate. Due to nonlinear effects, the reflected ultrasound will contain high-order or super-high harmonic components carrying vascular appearance information. The harmonic components are received by high-frequency array elements for imaging. This method enhances the contrast and sharpness of myocardial microvascular imaging, helping the diagnosis and treatment of cardiovascular dias.
The software and hardware technologies required for ultrasound superharmonic myocardial microvascular imaging were rearched. In terms of hardware, the
ultrasonic transmitting and receiving circuit suitable for ultrasound superharmonic myocardial microvascular imaging was designed and implemented, and it completed the high-efficiency emission of 5MHz ultrasound, as well as the low-noi amplification and acquisition of echo signals containing 30MHz weak harmonic components. At the same time, the common mode noi sources appearing in the system was analyzed theoretically, and the solution was given. The effective suppression of common mode noi was successfully realized. In terms of software, this paper rearched on some signal processing algorithms involved in ultrasonic superharmonic imaging systems, such as digital filter design and envelope detection, which successfully achieved the effective extraction of superharmonic signals.别样年华
The ultrasound superharmonic myocardial microvascular imaging platform was designed, and mi-phantom experiment was carried out. The three-dimensional imaging of the 110μm inner diameter microvascular phantom was performed with an axial resolution of 300μm and a lateral resolution of 100μm. The result indicates that the method of ultrasound superharmonic imaging on myocardial microvascular is of high-resolution imaging capabilities.
Key words：Ultrasound superharmonic imaging Myocardial microvascular Envelope detection Suppression of common mode noi
目录
摘要............................................................................................................................ . II 1 绪论
1.1课题背景及研究意义 (1)
1.2超谐波成像技术的发展及研究现状 (3)
1.3论文主要研究内容与组织结构 (8)
2 超谐波成像理论基础
2.1超声在组织中的传播特性 (10)
2.2超声的非线性特性 (12)
2.3传统超声成像原理及局限性 (14)
2.4双频超谐波成像原理及优势 (15)
2.5本章小结 (16)
3 超谐波收发电路的研究与设计
3.1需求分析 (18)节后安全教育
3.2系统结构设计 (19)
3.3关键模块研究 (19)
3.4本章小结 (31)
大屏嶂森林公园4 超谐波成像信号处理算法研究
4.1数字滤波器设计 (32)
4.2包络检测算法研究 (36)
4.3本章小结 (39)
祖国有多大
5 测试结果与分析
普通话考试技巧
5.1测试平台设计 (40)
忆江南古诗原文
5.2测试结果分析 (42)
5.3本章小结 (45)
6 总结与展望
6.1本文总结 (46)炒茄子怎么炒
6.2工作展望 (47)
致谢 (48)
参考文献 (49)
