IEEE Trans Med Imaging. 2015 Dec;34(12):2618-31. doi: 10.1109/TMI.2015.2450992.
Plane strain tensor estimation using non-invasive vascular ultrasound elastography (NIVE) can be difficult to achieve using conventional focus beamforming due to limited lateral resolution and frame rate. Recent developments in compound plane wave (CPW) imaging have led to high speed and high resolution imaging. In this study, we present the performance of NIVE using coherent CPW. We show the impact of CPW beamforming on strain estimates compared to conventional focus sequences. To overcome the inherent variability of lateral strains, associated with the low lateral resolution of linear array transducers, we use the plane strain incompressibility to constrain the estimator. Taking advantage of the approximate tenfold increase in frame rate of CPW compared with conventional focus imaging, we introduce a time-ensemble estimation approach to further improve the elastogram quality. By combining CPW imaging with the constrained Lagrangian speckle model estimator, we observe an increase in elastography quality (∼ 10 dB both in signal-to-noise and contrast-to-noise ratios) over a wide range of applied strains (0.02 to 3.2%).
使用非侵入性血管超声弹性成像（NIVE）进行平面应变张量估计可能由于横向分辨率和帧率有限而难以通过常规聚焦波束形成来实现。最近在复合平面波（CPW）成像方面的发展实现了高速和高分辨率成像。在这项研究中，我们展示了使用相干 CPW 的 NIVE 的性能。我们展示了 CPW 波束形成对与传统聚焦序列相比的应变估计的影响。为了克服与线性阵列换能器的低横向分辨率相关的横向应变的固有可变性，我们使用平面应变不可压缩性来约束估计器。利用 CPW 与传统聚焦成像相比帧速率提高约十倍的优势，我们引入了时间集成估计方法来进一步提高弹性图的质量。通过将 CPW 成像与约束拉格朗日散斑模型估计器相结合，我们观察到在广泛的应用应变范围内（0.02 至 3.2%），弹性成像质量（信号与噪声比和对比度噪声比均提高约 10dB）得到提高。
