基于声辐射力超弹性成像的晶状体力学特性定量测量研究

发布时间：2018-05-08 20:36

本文选题：医用超声系统 + 超声弹性成像　；参考：《深圳大学》2017年硕士论文

【摘要】：晶状体是眼球屈光系统的重要组成部分,也是唯一具有调节能力的屈光间质。晶状体的生物力学特性在晶状体调节功能中扮演重要的角色,并关系到有关疾病的诊断。由于晶状体的调节功能会随着年龄的增长持续退化,形成老视和白内障等疾病,严重影响中老年人的生活质量,也带来了巨大的公共医疗负担。目前,由于我们对老视和白内障的致病机制缺乏明确的认识,尚未找到一种确定的方法可以延缓症状的发展。因此,一种能够在体,无创和准确评估晶状体力学特性的研究方法,能够帮助我们解释老视和白内障的致病机制,监测老视和白内障等晶状体疾病的发展过程,进而研究相应的预防和治疗方法。本论文提出一种基于超声声辐射力在体定量测量新西兰兔晶状体力学特性的新方法。本研究基于Verasonics Vantage256超声平台,采用超声辐射力激励晶状体局部振动,并采用平面波快速成像的方式检测晶状体的振动信息。测量了振动传播的群速度与相速度,基于Voigt模型获得频散与弹性和粘性模量的关系,通过非线性拟合得到对应的粘弹性值。本论文先以离体的猪眼球和牛眼球为实验对象,实验结果表明,猪眼晶状体的群速度,杨氏模量和弹性值都大于牛眼晶状体的值,均有显著性差异。离体压缩实验的结果与超声实验结果一致,一定程度上验证了超声平台的有效性。在体实验是以四组不同日龄的新西兰白兔为实验对象,比较在同样能量的声辐射力下,不同组新西兰兔晶状体的位移,群速度,杨氏模量的差异。结果表明,随着日龄的增加,最大位移逐渐减小,群速度和杨氏模量逐渐增大。群速度与日龄的相关系数R=0.84,P5×10-8,群速度与体重的相关系数R=0.83,P8×10-8,表明样品的群速度与日龄和体重都有较强的线性相关性。本论文提出了一种在体,无创的测量晶状体力学特性的方法,实验结果表明,基于超声声辐射力的晶状体力学特性定量测量可有效反映晶状体力学特性的变化,并通过动物实验验证了在体应用的可行性。有望发展成一种晶状体力学特性的在体测量技术并用于老视的发病机制和治疗方法的研究。
[Abstract]:Lens is an important part of the refractive system of the eyeball, and is the only refractive stroma with adjustable ability. The biomechanical properties of lens play an important role in lens regulation and are related to the diagnosis of related diseases. As the regulating function of lens continues to degenerate with the increase of age, diseases such as presbyopia and cataract, which seriously affect the quality of life of middle-aged and elderly people, also bring a huge burden of public medical care. At present, due to the lack of a clear understanding of the pathogenesis of presbyopia and cataract, no definitive method has been found to delay the development of symptoms. Therefore, a research method that can evaluate the mechanical properties of lens in vivo, noninvasive and accurately can help us explain the pathogenic mechanism of presbyopia and cataract and monitor the development of lens diseases such as presbyopia and cataract. Then the corresponding prevention and treatment methods are studied. In this paper, a new method for quantitative measurement of lens mechanical properties in New Zealand rabbits based on ultrasonic radiation force in vivo is proposed. Based on Verasonics Vantage256 ultrasonic platform, the local vibration of lens is excited by ultrasonic radiation force, and the vibration information of lens is detected by plane wave fast imaging. The group velocities and phase velocities of vibration propagation were measured. Based on the Voigt model, the relationship between dispersion and elastic and viscous modulus was obtained, and the corresponding viscoelastic values were obtained by nonlinear fitting. In this paper, in vitro porcine and bovine eyeballs were used as experimental objects. The results showed that the group velocity, Young's modulus and elasticity of porcine lens were higher than those of bovine lens, and there were significant differences. The results of in vitro compression experiments are consistent with those of ultrasonic experiments, which to some extent verify the validity of the ultrasonic platform. In vivo, four groups of New Zealand white rabbits of different ages were used to compare the differences of lens displacement, group velocity and Young's modulus in different groups under the same energy of acoustic radiation. The results show that the maximum displacement decreases and the group velocity and Young's modulus increase with the increase of day age. The correlation coefficient between group velocity and body weight was 0.84 脳 10 ~ (-8), and the correlation coefficient between group velocity and body weight was 0.83 脳 10 ~ (-8), which indicated that the group velocity had a strong linear correlation with age and body weight. In this paper, a method of measuring lens mechanical properties in vivo and non-invasive is proposed. The experimental results show that quantitative measurement of lens mechanical properties based on ultrasonic acoustic radiation can effectively reflect the change of lens mechanical properties. The feasibility of in vivo application was verified by animal experiments. It is expected to develop into an in vivo measurement of lens mechanical properties and be used in the study of pathogenesis and treatment of presbyopia.
【学位授予单位】：深圳大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB559;R770.4

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