Delaware Rehabilitation Institute, University of Delaware, USA.
Delaware Rehabilitation Institute, University of Delaware, USA.
J Biomech. 2014 Jun 3;47(8):1806-9. doi: 10.1016/j.jbiomech.2014.03.030. Epub 2014 Mar 26.
Material properties of tissue in vivo present an opportunity for clinical analysis of healing progression and pathologies as well as provide an excellent research tool yielding quantified data for longitudinal and cross population studies. Echogenicity is a material׳s ability to reflect sound and, using ultrasound, it has been shown to increase with tendon tension in vitro, though this non-invasive measurement technique for determining mechanical properties has not been tested in vivo. The aim of this study was to establish if echogenicity, seen by the increase in image brightness, could be correlated to stress within a tissue. 18 Achilles tendons were imaged in the sagittal and transverse planes while producing a series of isometric contractions starting from rest and producing the torque equivalent of 0.5, 1.0, 1.5, and 2.0× body weights. Manual tracing identified the tendon in each of the images. The cross-sectional area determined from the transverse plane images in conjunction with the tendon force yielded the tendon stress. The echogenicity of the tendon was determined from the mean brightness change from rest to each of the contraction cases, measured from the sagittal plane images. A weak correlation existed between the echogenicity and stress (R=0.25) but it was found that there was no significant change in axial area during contraction (p=0.683) establishing the tendon as incompressible. Echogenicity proved to be non-functional for measuring the mechanical properties of the Achilles tendon due to the additional factors included with in vivo testing e.g. tendon twist and multi-axial loading.
组织的材料特性为临床分析愈合进展和病理提供了机会，同时也为纵向和跨人群研究提供了量化数据的优秀研究工具。回声性是物质反射声音的能力，通过超声已经表明，在体外，随着肌腱张力的增加，回声性会增加，尽管这种用于确定机械性能的非侵入性测量技术尚未在体内进行测试。本研究的目的是确定通过图像亮度的增加看到的回声性是否可以与组织内的应力相关联。18 跟腱在矢状面和横断面成像，同时从休息开始产生一系列等长收缩，产生相当于 0.5、1.0、1.5 和 2.0 倍体重的扭矩。手动追踪在每个图像中识别出肌腱。从横断面图像确定的横截面积与肌腱力相结合，产生肌腱应力。从矢状面图像测量，从休息到每个收缩情况，确定肌腱的回声性，测量的是平均亮度变化。回声性和应力之间存在弱相关性（R=0.25），但发现在收缩期间轴向区域没有明显变化（p=0.683），这表明肌腱是不可压缩的。由于体内测试中包含的额外因素，例如肌腱扭曲和多轴向加载，回声性证明对于测量跟腱的机械性能是不可用的。
