Tissues exhibiting quasi-periodic structures can be modeled as a collection of diffuse scatterers and coherent scatterers. The mean scatterer spacing (MSS) of coherent and quasi-periodic components is directly related to tissue microstructure and has become an important quantitative ultrasound (QUS) parameter in the characterization of quasi-periodic tissues. In this paper, a review of the literature on the development of MSS as a QUS parameter was conducted. First, a unified theoretical background of MSS estimates was provided. Then, the application of MSS estimates was summarized with respect to liver, spleen, breast, bone, muscle, and other tissues. MSS estimation techniques were applied to (a) the diagnosis of hepatitis, liver fibrosis and cirrhosis, and lesions in tissues such as liver, breast, and spleen; (b) the differentiation between benign and malignant breast tumors, and the grading of breast cancer; (c) the detection of cancellous bone; and (d) the monitoring of the efficacy of treatments such as thermal ablation, with various levels of success. Future developments were also discussed in terms of real-time implementation of MSS estimates, local MSS estimation, relationship of MSS to other QUS parameters, combination of MSS with other QUS parameters, in vivo validation of MSS estimates, MSS parametric imaging, and three-dimensional ultrasound tissue characterization.

中文翻译：

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平均散射间距超声组织表征综述

具有准周期结构的组织可以建模为漫射散射体和相干散射体的集合。相干和准周期分量的平均散射体间距 (MSS) 与组织微观结构直接相关，已成为表征准周期组织的重要定量超声 (QUS) 参数。在本文中，对将 MSS 发展为 QUS 参数的文献进行了回顾。首先，提供了统一的 MSS 估计理论背景。然后，总结了 MSS 估计在肝脏、脾脏、乳房、骨骼、肌肉和其他组织方面的应用。MSS估计技术应用于（a）肝炎、肝纤维化和肝硬化以及肝、乳腺、脾等组织病变的诊断；(b) 乳腺肿瘤良恶性的鉴别，以及乳腺癌的分级；(c) 松质骨的检测；(d) 监测治疗效果，如热消融，取得不同程度的成功。还讨论了 MSS 估计的实时实施、局部 MSS 估计、MSS 与其他 QUS 参数的关系、MSS 与其他 QUS 参数的组合、MSS 估计的体内验证、MSS 参数成像和三三维超声组织表征。