Carotid plaque rupture can result in stroke or transient ischemic attack that can be devastating for patients. Ultrasound strain imaging provides a noninvasive method to identify unstable plaque likely to rupture. Axial, lateral and shear strains in carotid plaque have been shown to be linked to carotid plaque instability. Recently, there has been interest in using principal strains, which do not depend on angle of insonification of the carotid artery for quantifying instability in plaque along the longitudinal view. In this work relationships between angle dependent axial, lateral and shear strain along with axis independent principal strains are compared. Three strain indices were defined, 1) Average Mean Strain (AMS), 2) Maximum Mean Strain (MMS) and 3) Mean Standard Deviation (MSD) to identify relationships between these five strain image types in a group of 76 in vivo patients. The maximum principal strain demonstrated the highest strain values when compared to axial strain for all patients with a linear regression slope of 1.6 and a y intercept of 2.4 percent strain for AMS. The maximum shear strain when compared to shear strain had a slope of 1.15 and a y intercept of 0.21 percent for AMS. Next, the effect of insonification angle, which is the angle subtended by the artery at the location of plaque was studied. Patients were divided into three sub groups, i.e. less than 5 degrees (n = 31), between 5 and 10 degrees (n = 24) and above 10 degrees (n = 21). The angle of insonification did not make a significant difference between the three angle groups when comparing the relationship between the angle dependent and independent strain values.

中文翻译：

---

使用纵向视图中的主要应变进行体内颈动脉应变成像

颈动脉斑块破裂可导致中风或短暂性脑缺血发作，这对患者来说可能是毁灭性的。超声应变成像提供了一种非侵入性方法来识别可能破裂的不稳定斑块。颈动脉斑块中的轴向、横向和剪切应变已被证明与颈动脉斑块不稳定性有关。最近，人们对使用不依赖颈动脉超声角度的主应变来量化沿纵向视图中斑块的不稳定性感兴趣。在这项工作中，对角度相关的轴向、横向和剪切应变以及与轴无关的主应变之间的关系进行了比较。定义了三个应变指数，1) 平均平均应变 (AMS)，2) 最大平均应变 (MMS) 和 3) 平均标准偏差 (MSD)，用于识别一组 76 名体内患者中这五种应变图像类型之间的关系。与所有患者的轴向应变相比，最大主应变表现出最高的应变值，对于 AMS，线性回归斜率为 1.6，y 截距为 2.4%。与剪切应变相比，最大剪切应变的斜率为 1.15，AMS 的 y 截距为 0.21%。接下来，研究了声波角的影响，即斑块位置处动脉对着的角度。患者被分为三个亚组，即小于 5 度（n = 31）、介于 5 度和 10 度之间（n = 24）和大于 10 度（n = 21）。