骨组织超声背散射相关技术研究

发布时间：2018-07-15 11:18

【摘要】：骨质疏松是一种钙、磷等矿物质从骨骼中流失所导致的病症，不易治疗，预防诊断很重要。我国由于人口基数大、老龄化加剧等因素尤其严重，所以需要一种简单方便、行之有效的诊断手段。超声学方法无辐射、廉价，在医疗领域的各个方面都得到了广泛的应用。超声背散射方法能够计算出骨小梁的相关参数，蕴含丰富的微结构信息，潜力非常大。本文研究如何有效的从超声背散射信号中提取平均骨小梁间距，主要工作包括：首先，论证了超声在松质骨中传播的散射声学模型，建立了圆柱体模型和球体模型，分析了背散射信号与骨小梁间距的关系，提出在SSA方法基础上应用编码激励技术，以期能够提高SSA方法的准确性。然后，实现了超声背散射测量系统，包含前端和后端两部分，前端包括发射接收电路，基于FPGA的主控部分，编写了逻辑程序并仿真验证；后端包括采集卡和上位机，以及界面和后端信号处理程序。系统可用于超声波信号的发射与接收，并自动保存数据。其次，建立了骨组织仿真模型，模拟骨小梁结构和探头的发射与接收。变换骨组织的的相关参数，验证SSA方法的鲁棒性，然后在包含噪声的情况下发射编码信号，验证编码激励技术能否提高该方法的准确性。最后，进行了离体骨样本实验，采用SSA方法对超声背散射信号进行重构并分析，之后对比编码发射的计算结果，说明SSA方法及编码激励技术在超声背散射信号的测量中具有较高的可行性。
[Abstract]:Osteoporosis is a disease caused by the loss of calcium, phosphorus and other minerals from the bone. Because of the large population base and the aggravation of aging, China needs a simple, convenient and effective diagnostic method. Ultrasonic methods are radiation-free and inexpensive, and have been widely used in various fields of medicine. Ultrasonic backscattering method can calculate the relevant parameters of bone trabeculae, which contains abundant microstructural information and has great potential. This paper studies how to extract the mean trabecular spacing effectively from ultrasonic backscattering signal. The main work includes: firstly, the acoustic model of ultrasonic scattering in cancellous bone is demonstrated, and the cylindrical model and spherical model are established. The relationship between backscatter signal and bone trabecular spacing is analyzed. Based on the SSA method, the coded excitation technique is proposed to improve the accuracy of the SSA method. Then, the ultrasonic backscattering measurement system is realized, which includes the front end and the back end. The front end includes the transmitting and receiving circuit, the main control part based on FPGA, the logic program and the simulation verification, the back end includes the data acquisition card and the upper computer. And interface and back-end signal processor. The system can be used to transmit and receive ultrasonic signals and save data automatically. Secondly, a bone tissue simulation model is established to simulate the transmission and reception of the trabecular structure and the probe. The robustness of the SSA method is verified by transforming the relevant parameters of bone tissue. Then the coding signal is transmitted under the condition of noise to verify whether the coding excitation technology can improve the accuracy of the method. Finally, in vitro bone sample experiment, SSA method is used to reconstruct and analyze the ultrasonic backscatter signal, and then the calculated results of coded emission are compared. It shows that SSA method and coded excitation technique are more feasible in ultrasonic backscatter signal measurement.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：R445.1;R580

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