ATTENUATION MEASUREMENT UNCERTAINTIES CAUSED BY SPECKLE STATISTICS
ATTENUATION MEASUREMENT UNCERTAINTIES CAUSED BY SPECKLE STATISTICS
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DOI：
10.1121/1.393946
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发表时间：
1986-09-01
影响因子：
2.4
通讯作者：
PARKER, KJ
中科院分区：
文献类型：
--
作者：
PARKER, KJ
衰减测量可以从反向散射信号随非均匀材料深度的衰减得出。在肝脏组织等情况下，由脉冲和波束宽度定义的样本体积中可能包含许多小的不均匀性，瑞利统计描述了反向散射压力大小的随机性质。散斑的统计数据是离散频率衰减估计以及带宽上衰减的幅度和频率依赖性的不确定性的基础。本文根据感兴趣区域的尺寸和超声系统的带宽等参数推导了衰减幅度和频率依赖性的标准偏差的表达式。使用已发表的数据给出了实际示例，并与测量“衰减斜率”的其他技术进行了比较。该分析深入了解了变量之间的权衡，例如感兴趣区域的尺寸和形状，以及时域和频域中的数据分段。
Attenuation measurements can be derived from the decay of backscattered signal with depth in an inhomogeneous material. In cases such as liver tissue, where many small inhomogeneities are likely to be included in sample volumes defined by pulse and beam widths, Rayleigh statistics described the random nature of the magnitude of backscattered pressure. The statistics of speckle underlie the uncertainties in estimates of attenuation at discrete frequencies, and of the magnitude and frequency dependence of attenuation over a bandwidth. This paper derives expressions for the standard deviations of attenuation magnitude and frequency dependence in terms of parameters such as the dimensions of the region of interest, and the bandwidth of the ultrasonic system. Practical examples are given using published data, and comparisons to other techniques which measure "attenuation slope" are made. The analysis yields insights into trade-offs among variables such as the dimensions and shape of regions of interest, and the segmenting of data in time and frequency domain.