Unifying Concepts of Statistical and Spectral Quantitative Ultrasound Techniques
Unifying Concepts of Statistical and Spectral Quantitative Ultrasound Techniques
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DOI：
10.1109/tmi.2015.2479455
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发表时间：
2016-02-01
影响因子：
10.6
通讯作者：
Cloutier, Guy
中科院分区：
文献类型：
--
作者：
Destrempes, Francois;Franceschini, Emilie;Cloutier, Guy
使用射频（RF）背散射信号的定量超声（QUS）技术已用于许多器官系统的组织表征。一种方法是使用反向散射回波的幅度和频率依赖性来量化组织结构。另一种方法是使用回波包络的一阶统计特性作为组织微结构的签名。我们建议统一这些QUS概念。为此，引入了零差K分布的混合物来模拟回波包络，以及基于回波信号谱的估计方法和其参数的物理解释。特别是，总的，相干的和扩散的信号功率相关的建议的混合物模型中明确表示的结构因子先前研究描述的后向散射系数（BSC）。然后，在红细胞（RBC）聚集的上下文中说明这种方法。实验结果表明，总的，相干的和扩散的信号功率的频谱结构因子大小和衰减估计的结构参数确定。双因素重复测量ANOVA检验表明，衰减（p值为0.077）和衰减补偿（p值为0.527）对弥散与总功率比无显著影响。这些结果为理解超声图像一阶统计的物理意义及其与QUS技术的关系迈出了又一步。考虑到结构因子理论上可以模拟散射体的任何空间分布，所提出的统一概念应该适用于血液以外的其他生物组织。
Quantitative ultrasound (QUS) techniques using radiofrequency (RF) backscattered signals have been used for tissue characterization of numerous organ systems. One approach is to use the magnitude and frequency dependence of backscatter echoes to quantify tissue structures. Another approach is to use first-order statistical properties of the echo envelope as a signature of the tissue microstructure. We propose a unification of these QUS concepts. For this purpose, a mixture of homodyned K-distributions is introduced to model the echo envelope, together with an estimation method and a physical interpretation of its parameters based on the echo signal spectrum. In particular, the total, coherent and diffuse signal powers related to the proposed mixture model are expressed explicitly in terms of the structure factor previously studied to describe the backscatter coefficient (BSC). Then, this approach is illustrated in the context of red blood cell (RBC) aggregation. It is experimentally shown that the total, coherent and diffuse signal powers are determined by a structural parameter of the spectral Structure Factor Size and Attenuation Estimator. A two-way repeated measures ANOVA test showed that attenuation (p-value of 0.077) and attenuation compensation (p-value of 0.527) had no significant effect on the diffuse to total power ratio. These results constitute a further step in understanding the physical meaning of first-order statistics of ultrasound images and their relations to QUS techniques. The proposed unifying concepts should be applicable to other biological tissues than blood considering that the structure factor can theoretically model any spatial distribution of scatterers.