Resolution and Speckle Reduction in Cardiac Imaging.
Resolution and Speckle Reduction in Cardiac Imaging.
复制标题
DOI：
10.1109/tuffc.2020.3034518
复制
发表时间：
2021-04
期刊：
影响因子：
--
通讯作者：
Trahey G
中科院分区：
文献类型：
--
作者：
Bottenus N;LeFevre M;Cleve J;Crowley AL;Trahey G
心脏成像依赖于几种不同结构和功能组件的清晰可视化，以确定左心室和整体心脏健康状况。超声成像受到组织中亚波长散射体产生的特征散斑纹理的影响，该散斑纹理类似于底层组织结构上的乘性噪声。这种纹理的减少可以通过物理手段（例如空间或频率复合）或通过自适应图像处理来实现。这两类技术都需要在分辨率和散斑纹理减少之间进行权衡，这共同有助于提高整体图像质量和诊断价值。我们使用空间复合作为示例性散斑减少方法来评估心脏成像任务的这种权衡。空间复合对由多个子孔径位置的目标视图形成的去相关散斑图案进行平均，以牺牲有效孔径尺寸（以及横向分辨率）为代价来减少纹理。我们演示了使用一种新颖的合成孔径聚焦技术将来自聚焦光束的谐波反向散射数据分解为其孔径域空间频率分量，以实现组合的发射和接收复合。该工具允许在各种空间复合条件下对单次采集的匹配数据集进行评估。我们量化了成像体模中分辨率和纹理减少之间的权衡，并证明随着空间复合水平的增加，病变可检测性得到改善。我们对 25 名受试者进行了心脏超声检查，以评估对诊断成像有用的复合程度。其中，18 名受试者被纳入定性和定量分析。我们发现，根据所有病例的广义对比噪声比，复合改善了心内膜边界的可检测性，而更积极的复合使 18 例中有 10 例进一步改善。三位专家评审员评估了图像在多项诊断任务中的有用性，并对四种复合条件进行了排名（“无”、“低”、“中”、“高”）。与建议使用高水平复合的定量指标相反，评审者确定“低”通常是首选（77.9%），而在 21.2% 的情况下选择“无”或“中”。最后，我们简要讨论了这些结果对使用成像模型数据的其他散斑减少方法的推广。
Cardiac imaging depends on clear visualization of several different structural and functional components to determine left ventricular and overall cardiac health. Ultrasound imaging is confounded by the characteristic speckle texture resulting from sub-wavelength scatterers in tissues that is similar to a multiplicative noise on underlying tissue structure. Reduction of this texture can be achieved through physical means such as spatial or frequency compounding or through adaptive image processing. Techniques in both categories require a trade-off of resolution for speckle texture reduction, which together contribute to overall image quality and diagnostic value. We evaluate this trade-off for cardiac imaging tasks using spatial compounding as an exemplary speckle reduction method. Spatial compounding averages the decorrelated speckle patterns formed by views of a target from multiple subaperture positions to reduce the texture at the expense of active aperture size (and in turn lateral resolution). We demonstrate the use of a novel synthetic aperture focusing technique to decompose harmonic backscattered data from focused beams to their aperture domain spatial frequency components to enable combined transmit and receive compounding. This tool allows the evaluation of matched data sets from a single acquisition over a wide range of spatial compounding conditions. We quantified the trade-off between resolution and texture reduction in an imaging phantom and demonstrated improved lesion detectability with increasing levels of spatial compounding. We performed cardiac ultrasound on 25 subjects to evaluate the degree of compounding useful for diagnostic imaging. Of these, 18 subjects were included for both qualitative and quantitative analysis. We found that compounding improved detectability of the endocardial border according to the generalized contrast-to-noise ratio in all cases and more aggressive compounding made further improvements in 10 out of 18 cases. Three expert reviewers evaluated the images for their usefulness in several diagnostic tasks and ranked four compounding conditions (“None”, “Low”, “Medium”, “High”). Contrary to the quantitative metrics which suggested the use of high levels of compounding, the reviewers determined that “Low” was usually preferred (77.9%), while “None” or “Medium” were selected in 21.2% of cases. We conclude with a brief discussion of the generalization of these results to other speckle reduction methods using the imaging phantom data.