Quantitative Assessment of In Vivo Breast Masses Using Ultrasound Attenuation and Backscatter
Quantitative Assessment of In Vivo Breast Masses Using Ultrasound Attenuation and Backscatter
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DOI：
10.1177/0161734613480281
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发表时间：
2013-04-01
影响因子：
2.3
通讯作者：
Hall, Timothy J.
中科院分区：
文献类型：
--
作者：
Nam, Kibo;Zagzebski, James A.;Hall, Timothy J.
乳腺超声成像的临床分析是定性的，有助于超声乳腺成像报告和数据系统（US BI-RADS）词典，这有助于标准化成像评估。在该词典中的两个描述符，“后方声学特征”和“回声模式”内的质量，是直接相关的定量超声（QUS）参数，即，超声衰减和平均后向散射系数（BSC）。本研究的目的是量化乳腺肿块的超声衰减和背向散射，并研究这些QUS特性作为潜在的鉴别诊断标志物。射频（RF）回波信号来自在芯活检之前的特殊超声成像期间患有乳腺肿块的患者。还使用相同的系统设置从充分表征的体模中获得数据。肿块包括14个纤维腺瘤和10个癌。使用具有约束的最小二乘法离线估计位于肿瘤近端的声学路径的衰减。使用参考体模方法（RPM）估计BSC。使用RPM和混合方法评估每个质量内的衰减系数，并使用高斯形状因子模型估计有效散射体直径（ESD）。在除两个质量外的所有情况下，RPM获得的衰减估计值与使用混合方法进行的估计值一致。癌的衰减系数与频率的平均斜率比纤维腺瘤的平均斜率值大20%。计算衰减系数和肿块前后向尺寸的乘积，以估计每个肿块的总衰减。该值与BI-RADS评估的“后声学特征”相关性很好，从灰度图像中定性判断。几乎所有的肿块都被描述为“低回声”，因此不能对BI-RADS中回声模式结果与平均BSC值的相关性做出强有力的声明。然而，大多数癌表现出较低的值的频率平均BSC比纤维腺瘤。平均ESD单独没有区分质量类型，但纤维腺瘤有更大的变异性ESD内的ROI比浸润性导管癌。本研究表明，有可能使用与BSC相关的衰减和QUS参数作为定量描述符。
Clinical analysis of breast ultrasound imaging is done qualitatively, facilitated with the ultrasound breast imaging-reporting and data system (US BI-RADS) lexicon, which helps to standardize imaging assessments. Two descriptors in that lexicon, "posterior acoustic features" and the "echo pattern" within a mass, are directly related to quantitative ultrasound (QUS) parameters, namely, ultrasound attenuation and the average backscatter coefficient (BSC). The purpose of this study was to quantify ultrasound attenuation and backscatter in breast masses and to investigate these QUS properties as potential differential diagnostic markers. Radio frequency (RF) echo signals were from patients with breast masses during a special ultrasound imaging session prior to core biopsy. Data were also obtained from a well characterized phantom using identical system settings. Masses include 14 fibroadenomas and 10 carcinomas. Attenuation for the acoustic path lying proximal to the tumor was estimated offline using a least squares method with constraints. BSCs were estimated using a reference phantom method (RPM). The attenuation coefficient within each mass was assessed using both the RPM and a hybrid method, and effective scatterer diameters (ESDs) were estimated using a Gaussian form factor model. Attenuation estimates obtained with the RPM were consistent with estimates done using the hybrid method in all cases except for two masses. The mean slope of the attenuation coefficient versus frequency for carcinomas was 20% greater than the mean slope value for the fibroadenomas. The product of the attenuation coefficient and anteroposterior dimension of the mass was computed to estimate the total attenuation for each mass. That value correlated well with the BI-RADS assessment of "posterior acoustic features" judged qualitatively from gray scale images. Nearly all masses were described as "hypoechoic," so no strong statements could be made about the correlation of echo pattern findings in BI-RADS with the averaged BSC values. However, most carcinomas exhibited lower values for the frequency-average BSC than fibroadenomas. The mean ESD alone did not differentiate the mass type, but fibroadenomas had greater variability in ESDs within the ROI than that found for invasive ductal carcinomas. This study demonstrates the potential to use attenuation and QUS parameters associated with the BSC as quantitative descriptors.