Quantitative Spatially Modulated Ultrasound Radiation Force Elastography

描述（由申请人提供）：需要量化组织硬度以辅助疾病诊断。超声和MRI技术存在用于组织硬度的体内量化，但是这些方法由于附加设备而复杂化，并且执行起来可能是耗时的。在这里，我们建议开发一种我们发明的方法，称为空间调制超声辐射力（SMURF）成像。SMURF成像的原理是利用声辐射力在未知剪切模量的组织中产生已知波长的剪切波，并测量传播剪切波的频率以确定组织的剪切模量。在密度ρ和剪切模量G的线性弹性材料中，剪切波的频率f和波长λ通过G=（λ *f）2 ρ相关。因此，通过感应已知波长的剪切波并测量所得的振动频率，可以估计组织剪切模量。与应用已知频率并估计所得剪切波的波长的现有方法相比，SMURF成像使用阵列波束成形技术来产生期望波长的剪切波。SMURF成像方法的一个关键创新是，波长估计的困难问题被更简单的频率估计任务所取代，频率估计通常由多普勒超声仪器执行。SMURF不需要额外的设备，只需修改软件即可在现代超声扫描仪上进行。与声辐射力脉冲（ARFI）成像（使用聚焦超声束来移动组织）相比，SMURF使用空间变化的辐射力来创建明确的剪切波长并允许量化。我们提出了一个综合的研究计划，以开发所需的波束形成技术，以产生空间变化的辐射力，SMURF成像是能够量化的组织刚度具有足够的精度，诊断有用的，并表明SMURF成像可用于估计组织的粘弹性参数。公共卫生相关性我们已经创建了一种称为空间调制超声辐射力（SMURF）成像的新技术，用于组织硬度估计。SMURF使用特殊形状的超声波束在组织中产生剪切波;这些波的频率揭示了组织的硬度。我们提出的研究，开发合适的实施技术的临床超声扫描仪，并确定这种方法的准确性。

DESCRIPTION (provided by applicant): Quantification of tissue stiffness is needed assist in diagnosis of disease. Ultrasound and MRI techniques exist for in vivo quantification of tissue stiffness, but these methods are complicated by additional equipment and can be time consuming to perform. Here we propose to develop a method we have invented called Spatially Modulated Ultrasound Radiation Force (SMURF) imaging. The principle of SMURF imaging is to use acoustic radiation force to generate a shear wave of known wavelength in tissue of unknown shear modulus and measure the frequency of the propagating shear wave to determine the shear modulus of the tissue. In a linear elastic material of density rho and shear modulus G, a shear wave's frequency f and wavelength lambda are related by G=(lambda*f)2rho. Therefore, by inducing a shear wave of known wavelength and measuring the resulting vibration frequency tissue shear modulus may be estimated. In contrast to existing methods, which apply a known frequency and estimate the wavelength of the resulting shear wave, SMURF imaging uses array beamforming techniques to produce a shear wave of a desired wavelength. A key innovation in the SMURF imaging method is that the difficult problem of wavelength estimation is replaced by the much simpler task of frequency estimation, which is routinely performed by Doppler ultrasound instruments. SMURF requires no extra apparatus and can be performed on modern ultrasound scanners with only software modifications. In contrast to Acoustic Radiation Force Impulse (ARFI) imaging, which uses a focused beam of ultrasound to displace tissue, SMURF uses a spatially varying radiation force to create a definite shear wavelength and allow for quantification. We present an integrated research plan to develop beamforming techniques needed to generate spatially varying radiation force, to show that SMURF imaging is capable of quantifying tissue stiffness with sufficient precision to be diagnostically useful, and to show that SMURF imaging can be used to estimate viscoelastic parameters of tissue. PUBLIC HEALTH RELEVANCE We have created a new technique called Spatially Modulated Ultrasound Radiation Force (SMURF) imaging for tissue stiffness estimation. SMURF uses specially shaped ultrasound beams to generate shear waves in tissue; the frequency of these waves reveals the tissue stiffness. We propose studies to develop suitable implementation techniques for a clinical ultrasound scanner and to determine the accuracy of this method.