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Backscatter and attenuation characterization of ventricular myocardium.

机译：心室心肌的反向散射和衰减特性。

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摘要

This Dissertation presents quantitative ultrasonic measurements of the myocardium in fetal hearts and adult human hearts with the goal of studying the physics of sound waves incident upon anisotropic and inhomogeneous materials. Ultrasound has been used as a clinical tool to assess heart structure and function for several decades. The clinical usefulness of this noninvasive approach has grown with our understanding of the physical mechanisms underlying the interaction of ultrasonic waves with the myocardium.;In this Dissertation, integrated backscatter and attenuation analyses were per- formed on midgestational fetal hearts to assess potential differences in the left and right ventricular myocardium. The hearts were interrogated using a 50 MHz transducer that enabled finer spatial resolution than could be achieved at more typical clinical frequencies. Ultrasonic data analyses demonstrated different patterns and relative levels of backscatter and attenuation from the myocardium of the left ventricle and the right ventricle.;Ultrasonic data of adult human hearts were acquired with a clinical imaging system and quantified by their magnitude and time delay of cyclic variation of myocardial backscatter. The results were analyzing using Bayes Classification and ROC analysis to quantify potential advantages of using a combination of two features of cyclic variation of myocardial backscatter over using only one or the other feature to distinguish between groups of subjects. When the subjects were classified based on hemoglobin A1c, the homeostasis model assessment of insulin resistance, and the ratio of triglyceride to high-density lipoprotein-cholesterol, differences in the magnitude and normalized time delay of cyclic variation of myocardial backscatter were observed. The cyclic variation results also suggested a trend toward a larger area under the ROC curve when information from magnitude and time delay of cyclic variation is combined using Bayes classification than when each feature is analyzed individually.;Ultrasound continues to be a powerful tool that enables noninvasive quantification of material properties. The studies in this Dissertation show that understanding the physical mechanisms behind the interaction of sound waves with myocardium can reveal new information about the structure, composition and overall state of the heart.
机译：本论文提出了胎儿心脏和成年人类心脏心肌的定量超声测量，目的是研究入射在各向异性和非均质材料上的声波的物理性质。几十年来，超声已被用作评估心脏结构和功能的临床工具。随着我们对超声波与心肌相互作用的物理机制的理解，这种非侵入性方法的临床实用性得到了增长。本论文对妊娠中期胎儿的心脏进行了集成的反向散射和衰减分析，以评估胎儿心脏的潜在差异。左右心室心肌。使用50 MHz换能器对心脏进行询问，该换能器比在更典型的临床频率下实现的空间分辨率更好。超声数据分析显示左心室和右心室心肌的反向散射和衰减的模式和相对水平不同;;使用临床成像系统获取成人心脏的超声数据，并根据其周期性变化的幅度和时间延迟对其进行量化心肌后向散射。使用贝叶斯分类法和ROC分析法对结果进行了分析，以量化使用心肌后向散射的周期性变化的两个特征的组合而不是仅使用一个或另一个特征来区分对象组的潜在优势。根据血红蛋白A1c对受试者进行分类时，观察了胰岛素抵抗的稳态模型评估，甘油三酸酯与高密度脂蛋白胆固醇的比率，心肌后向散射的周期性变化幅度和归一化时延的差异。周期性变化的结果还表明，当使用贝叶斯分类组合周期性变化的幅度和时间延迟的信息时，与单独分析每个特征相比，ROC曲线下的面积趋向更大。超声仍然是一种强大的工具，可实现无创性材料性能的量化。本论文的研究表明，了解声波与心肌相互作用背后的物理机制可以揭示有关心脏的结构，组成和整体状态的新信息。

著录项

  • 作者

    Gibson, Allyson Ann.;

  • 作者单位

    Washington University in St. Louis.;

  • 授予单位 Washington University in St. Louis.;
  • 学科 Physics Acoustics.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 128 p.
  • 总页数 128
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 声学;
  • 关键词

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