Resolving Ultrasound Contrast Microbubbles Using Minimum Variance Beamforming
Resolving Ultrasound Contrast Microbubbles Using Minimum Variance Beamforming
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DOI：
10.1109/tmi.2018.2859262
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发表时间：
2019-01-01
影响因子：
10.6
通讯作者：
Sboros, Vassilis
中科院分区：
文献类型：
--
作者：
Diamantis, Konstantinos;Anderson, Tom;Sboros, Vassilis
已知最小方差（MV）波束形成可提高超声图像的横向分辨率并增强孤立点散射体的分离。本文的目的是评估自适应波束形成器的性能与流动的微泡（MB），这是相关的超分辨率超声成像。使用点散射体数据从单发射的模拟进行了补充的实验研究，使用毛细管体模和合成孔径实时超声系统（SARUS）。通过允许并排放置的两个散射体显示的最小距离、横向半峰全宽（FWHM）和峰旁瓣电平（PSL）评估MV性能。在管中，散射体的响应分离到196 μ m（或1.05 λ）的MV方法区分，而标准的延迟和总和（DAS）波束形成器无法实现这样的分离。对于来自MB的单个回波，还测量了高达九倍的FWHM减小，这有利于MV波束形成器。两个散射体之间的横向距离影响它们的FWHM值，并且散射体的轴向或面外位置的附加差异也影响它们的尺寸和外观。仿真和实验结果在横向分辨率方面是一致的。点散射体研究表明，所提出的MV成像方案相比DAS提供了清晰的分辨率优势。目前的超分辨率方法主要依赖于DAS波束形成器。相反，MV方法的使用可以提供更大数量的检测到的并且可能更好地定位的MB散射体。
Minimum Variance (MV) beamforming is known to improve the lateral resolution of ultrasound images and enhance the separation of isolated point scatterers. This paper aims to evaluate the adaptive beamformer's performance with flowing microbubbles (MBs) which are relevant to super-resolution ultrasound imaging. Simulations using point scatterer data from single emissions were complemented by an experimental investigation performed using a capillary tube phantom and the Synthetic Aperture Real-time Ultrasound System (SARUS). The MV performance was assessed by the minimum distance that allows the display of two scatterers positioned side-by-side, the lateral Full-Width-at-Half-Maximum (FWHM), and the Peak-Sidelobe-Level (PSL). In the tube, scatterer responses separated by down to 196 mu m (or 1.05 lambda) were distinguished by the MV method, while the standard Delay-And-Sum (DAS) beamformers were unable to achieve such separation. Up to ninefold FWHM decrease was also measured in favor of the MV beamformer for individual echoes from MBs. The lateral distance between two scatterers impacted on their FWHM value, and additional differences in the scatterers' axial or out-of-plane position also impacted on their size and appearance. The simulation and experimental results were in agreement in terms of lateral resolution. The point scatterer study showed that the proposed MV imaging scheme provided clear resolution benefits compared to DAS. Current super-resolution methods mainly depend on DAS beamformers. Instead, the use of the MV method may provide a larger number of detected, and potentially better localized, MB scatterers.