Parallel Receive Beamforming Improves the Performance of Focused Transmit-Based Single-Track Location Shear Wave Elastography.
Parallel Receive Beamforming Improves the Performance of Focused Transmit-Based Single-Track Location Shear Wave Elastography.
复制标题
并行接收光束形成可改善集中的基于发射的单轨位置剪切波弹性弹力的性能。
DOI：
10.1109/tuffc.2020.2998979
复制
发表时间：
2020-10
期刊：
影响因子：
--
通讯作者：
Doyley MM
中科院分区：
文献类型：
--
作者：
Ahmed R;Doyley MM
单道定位剪切波弹性成像(STL-SWI)对剪切波速(SWS)估计中的斑点噪声具有较强的鲁棒性，但它也不能幸免于其他非相干噪声源(如电子噪声)，这些噪声会增加SWS估计的方差。虽然并行接收波束成形实现的估计平均能够充分抑制这些噪声源，但这些波束成形技术通常依赖于宽发射波束(平面或发散)。虽然平面波成像等宽波束方法在超声研究系统中变得无处不在，但由于与硬件波束形成和更深的穿透能力兼容，临床系统通常使用聚焦传输波束。因此，提高基于聚焦传输的STL-Swei的噪声稳健性可能使其更容易转换为临床场景。在这项工作中，我们通过实验评估了STL-SWEI在固定和多个发射焦点情况下的并行波束形成性能。通过对模拟组织体模的成像，我们发现并行波束成形使聚焦区域弹性图信噪比(SNRE)提高了40.9%。对于相当于换能器间距的接收线间距，从三条平行线的平均估计在焦点区域(25 Mm)产生峰值SNRE，而在较浅区域(<；20 mm)需要更多数量的平行线(>；7)。波束形成线密度增加8倍，焦区SNRE仅增加13.2%。当希望在固定深度(如在推进焦深内)进行SWS量化时，使用更深的跟踪焦区可以获得更高的平行线计数并将峰值SNRE提高33%。多聚焦策略比单聚焦配置产生更低的SNRE。对于固定的跟踪焦区，基于模拟发射强度的深度相关平均充分考虑了发射波束宽度。这项工作的结果表明，STL-SWEI可以使用具有稳健噪声抑制能力的聚焦发射光束来实现。
Single track location shear wave elastography (STL-SWEI) is robust against speckle-induced noise in shear wave speed (SWS) estimates, however it is not immune to other incoherent sources of noise (such as electronic noise) that increase the variance in SWS estimates. Although estimation averaging enabled by parallel receive beamforming adequately suppresses these noise sources, these beamforming techniques often rely on broad transmit beams (plane or diverging). While broad beam approaches such as plane wave imaging are becoming ubiquitous in research ultrasound systems, clinical systems usually employ focused transmit beams due to compatibility with hardware beamforming and deeper penetration. Consequently, improving the noise robustness of focused transmit based STL-SWEI may enable easier translation to clinical scenarios. In this work, we experimentally evaluated the performance of parallel beamforming for STL-SWEI using fixed or multiple transmit focus. By imaging tissue-mimicking phantoms, we found that parallel beamforming improved the focal zone elastographic signal-to-noise ratio (SNRe) by 40.9%. For a receive line spacing equivalent to transducer pitch, averaging estimates from three parallel lines produced peak SNRe at the focal zone (25 mm) while at the shallower regions (<20 mm) a larger number of parallel lines (>7) were needed. Increasing the beamforming line density by a factor of 8 increased the focal zone SNRe only by 13.2%. When SWS quantification was desirable at a fixed depth (such as within the push focal depth), using a deeper tracking focal zone enabled higher parallel line count and improved the peak SNRe by 33%. The multi-focusing strategy produced a lower SNRe than the single focus configurations. For a fixed tracking focal zone, a depth-dependent averaging based on simulated transmit intensity adequately accounted for the transmit beamwidth. The results in this work demonstrated that STL-SWEI can be implemented using focused transmit beams with robust noise-suppression capability.