IEEE Trans Ultrason Ferroelectr Freq Control. 2016 Sep;63(9):1288-95. doi: 10.1109/TUFFC.2016.2543026. Epub 2016 Mar 17.
In the past decade, there has been an increased interest in characterizing cardiac tissue mechanics utilizing newly developed ultrasound-based elastography techniques. These methods excite the tissue mechanically and track the response. Two frequently used methods, acoustic radiation force impulse (ARFI) and shear-wave elasticity imaging (SWEI), have been considered qualitative and quantitative techniques providing relative and absolute measures of tissue stiffness, respectively. Depending on imaging conditions, it is desirable to identify indices of cardiac function that could be measured by ARFI and SWEI and to characterize the relationship between the measures. In this study, we have compared two indices (i.e., relaxation time constant used for diastolic dysfunction assessment and systolic/diastolic stiffness ratio) measured nearly simultaneously by M-mode ARFI and SWEI techniques. We additionally correlated ARFI-measured inverse displacements with SWEI-measured values of the shear modulus of stiffness. For the eight animals studied, the average relaxation time constant ( τ) measured by ARFI and SWEI were ([Formula: see text]) and ([Formula: see text]), respectively ([Formula: see text]). Average systolic/diastolic stiffness ratios for ARFI and SWEI measurements were 6.01±1.37 and 7.12±3.24, respectively ([Formula: see text]). Shear modulus of stiffness (SWEI) was linearly related to inverse displacement values (ARFI) with a 95% CI for the slope of 0.010-0.011 [Formula: see text] ( R(2)=0.73). In conclusion, the relaxation time constant and the systolic/diastolic stiffness ratio were calculated with good agreement between the ARFI- and SWEI-derived measurements. ARFI relative and SWEI absolute stiffness measurements were linearly related with varying slopes based on imaging conditions and subject tissue properties.
在过去的十年中，人们对利用新开发的基于超声的弹性成像技术来描述心脏组织力学特性的兴趣日益浓厚。这些方法通过机械激发组织并跟踪其响应来实现。两种常用的方法，声辐射力脉冲（ARFI）和剪切波弹性成像（SWEI），分别是定性和定量技术，分别提供组织硬度的相对和绝对测量值。根据成像条件，希望识别可以通过 ARFI 和 SWEI 测量的心脏功能指数，并描述这些测量值之间的关系。在这项研究中，我们比较了通过 M 模式 ARFI 和 SWEI 技术几乎同时测量的两个指数（即用于舒张功能评估的弛豫时间常数和收缩/舒张僵硬比）。我们还将 ARFI 测量的反向位移与 SWEI 测量的刚度剪切模量值进行了相关性分析。对于研究的八只动物，ARFI 和 SWEI 分别测量的平均弛豫时间常数（τ）为[公式：见正文]和[公式：见正文]（[公式：见正文]）。ARFI 和 SWEI 测量的收缩/舒张僵硬比分别为 6.01±1.37 和 7.12±3.24（[公式：见正文]）。刚度剪切模量（SWEI）与反向位移值（ARFI）呈线性相关，斜率的 95%置信区间为 0.010-0.011 [公式：见正文]（R2=0.73）。总之，ARFI 和 SWEI 衍生测量值之间的弛豫时间常数和收缩/舒张僵硬比计算具有良好的一致性。ARFI 相对和 SWEI 绝对硬度测量值与基于成像条件和对象组织特性的不同斜率呈线性相关。
