In conventional linear array (CLA)–based elastography tissue compression in one direction (e.g., axial) leads to an expansion in all other directions (lateral, elevation). Therefore, the estimation of the lateral displacements and strains may provide additional information on the tissue mechanical properties. However, these are not exploited fully due to the inherent limitation in lateral sampling. Recently, a method named actuator-assisted beam translation (ABT) was demonstrated to address this issue, wherein the focused beam was translated at subpitch locations using an external bench-top setup. However, because such bench-top setup may be impractical for routine clinical use, an ultrasound transducer was customized to have an internal actuator. The performance of the customized transducer was studied through experiments on phantoms for rotation elastography application, which requires precise lateral displacement estimation. Furthermore, the results obtained from ABT was compared against the currently practiced spatial displacement compounding (SDC) method, which is known to yield better quality lateral displacement estimates than conventional approaches. The results show that the ABT method yields a full-width half-maximum (FWHM) value, taken from the lateral profile across a point scatterer, which is 65% and 24% smaller than that obtained using CLA and SDC methods, respectively. Furthermore, the contrast-to-noise ratio (CNR) estimated from rotation elastogram obtained using ABT method is better by 300% and 35% compared with that obtained by using CLA and SDC methods, respectively. Furthermore, the results demonstrate an additional advantage of having larger field of view (FoV) for the ABT method compared with spatial compounding approach.

中文翻译：

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用于弹性成像的致动器辅助亚音高平移换能器：初步性能评估

在传统的基于线性阵列 (CLA) 的弹性成像中，一个方向（例如轴向）的组织压缩导致所有其他方向（横向、仰角）的扩张。因此，横向位移和应变的估计可以提供关于组织机械特性的附加信息。然而，由于横向采样的固有限制，这些并没有得到充分利用。最近，一种名为致动器辅助光束平移 (ABT) 的方法被证明可以解决这个问题，其中使用外部台式设置在亚间距位置平移聚焦光束。然而，由于这种台式设置对于常规临床使用可能不切实际，因此定制了超声换能器以具有内部致动器。通过用于旋转弹性成像应用的体模实验研究了定制换能器的性能，这需要精确的横向位移估计。此外，将从 ABT 获得的结果与目前实践的空间位移复合 (SDC) 方法进行比较，该方法已知比传统方法产生更好的横向位移估计。结果表明，ABT 方法产生的全宽半最大值 (FWHM) 值取自点散射体的横向轮廓，分别比使用 CLA 和 SDC 方法获得的值小 65% 和 24%。此外，与使用 CLA 和 SDC 方法获得的相比，使用 ABT 方法获得的旋转弹性图估计的对比度 (CNR) 分别提高了 300% 和 35%。