University of North Carolina at Chapel Hill, Department of Physics and Astronomy, Chapel Hill, North Carolina 27599, USA.
J Biomed Opt. 2011 Nov;16(11):116005. doi: 10.1117/1.3646211.
Measuring the elasticity distribution inside the human body is of great interest because elastic abnormalities can serve as indicators of several diseases. We present a method for mapping elasticity inside soft tissues by imaging surface acoustic waves (SAWs) with digital holographic interferometry. With this method, we show that SAWs are consistent with Rayleigh waves, with velocities proportional to the square root of the elastic modulus greater than 2-40 kPa in homogeneous tissue phantoms. In two-layer phantoms, the SAW velocity transitions approximately from that of the lower layer to that of the upper layer as frequency is increased in agreement with the theoretical relationship between SAW dispersion and the depth-dependent stiffness profile. We also observed deformation in the propagation direction of SAWs above a stiff inclusion placed 8 mm below the surface. These findings demonstrate the potential for quantitative digital holography-based elastography of soft tissues as a noninvasive method for disease detection.
测量人体内部的弹性分布具有重要意义，因为弹性异常可以作为几种疾病的指标。我们提出了一种通过数字全息干涉法对表面声波（SAW）成像来绘制软组织内部弹性的方法。通过这种方法，我们证明了 SAW 与瑞利波一致，在均匀组织模型中，速度与弹性模量的平方根成正比，大于 2-40 kPa。在两层模型中，随着频率的增加，SAW 速度从较低层过渡到较高层，与 SAW 色散与深度相关的刚度分布之间的理论关系一致。我们还观察到在距离表面 8 毫米的硬夹杂物上方，SAW 在传播方向上发生了变形。这些发现表明，基于定量数字全息术的软组织弹性成像作为一种非侵入性的疾病检测方法具有潜力。
