In-vivo MR Tractography and FEM Study of Human Lower Leg

人体小腿的体内 MR 纤维束成像和 FEM 研究

• 批准号: 7026189
• 负责人: Shantanu Sinha
• 金额: $ 29.15万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-15 至 2010-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7026189
• 关键词: clinical research; human; leg; model; muscle

DESCRIPTION (provided by applicant): Current models of the musculo-skeletal system fail to accurately predict the relationship between muscle fiber shortening and the relative excursion of the tendino-skeletal interfaces. A simple example of this would be that the tendino-calcaneal interface at the ankle moves approximately 30 mm for a 15 mm soleus muscle fiber shortening. We propose multiple mechanical gain systems to amplify the muscle fiber excursion and the basic design of this proposal is to evaluate these gain systems and determine if they are sufficient to explain the discrepancy between muscle fiber length changes and movement of the ankle. A secondary goal is to understand the underlying mechanics, particularly as it relates to the distortion of muscle tissue during a contraction. The hypotheses to be tested include (1) The proximo-distal displacement of the fiber-aponeurosis interface during an isometric contraction will be due in part to an increase in angle of the interface as well as due to a shortening of the distance between the aponeuroses of insertion and origin, and (2) The proximo-distal displacement of the most distal soleus fiber-aponeurosis of insertion will be less than the linear displacement of the Achilles' tendon insertion point on the calcaneus due to a sling factor that is intrinsic to the musculotendinous-skeletal anatomy. Advanced MR imaging techniques of fiber tracking with Diffusion Tensor Tractography at 3 Tesla, Phase Contrast Imaging, and MRI-compatible dynamometry as well as Finite Element Modeling will be used in combination. This is particularly apt for the PA which asks that a "multidisciplinary research" with an "integration of principles from a diversity of technical and biomedical field" be used to "provide new understanding" and "effectively address a biomedical problem". We will experimentally investigate several design features of the Triceps Surae Complex that could account for apparent paradoxes in current descriptions of muscle performance and generate a model consistent with our experimental observations. Our goal is better prediction of intrinsic muscle properties and joint performance. Essential variables that we will measure to test these hypotheses include muscle volume, muscle surface area, fiber orientation, aponeurosis separation (muscle thickness), aponeurosis dimension and strain properties of aponeurosis. In 3Dal space, these variables will be quantified at systematically varying ankle joint positions and muscle activation levels. From a past grant from NASA/NSBRI, we have had considerable success in developing most of these relatively difficult techniques, (as per publications in Appendix). The developed model will help to gain better insight into the design features of muscle-tendon complex, a better understanding of chronic muscle adaptations such as disuse atrophy and better prediction of outcomes of surgical treatments such as aponeurotomy, tenectomy and tenotomy.

描述（由申请人提供）：肌肉骨骼系统的当前模型无法准确预测肌纤维缩短与肌腱骨骼界面相对偏移之间的关系。一个简单的例子是，对于15 mm的比目鱼肌纤维缩短，踝关节处的肌腱-跟骨界面移动约30 mm。我们提出了多个机械增益系统来放大肌纤维的偏移，这个建议的基本设计是评估这些增益系统，并确定它们是否足以解释肌纤维长度变化和踝关节运动之间的差异。第二个目标是了解潜在的力学，特别是当它涉及到肌肉组织在收缩期间的扭曲。待检验的假设包括：（1）等长收缩期间纤维-腱膜界面的近端-远端位移部分是由于界面角度的增加以及由于附着腱膜与起点之间距离的缩短，（2）比目鱼肌最远端纤维的近-远位移-由于肌肉肌腱-骨骼解剖结构固有的吊索因素，附着腱膜将小于跟骨上的跟腱附着点的线性位移。将结合使用先进的MR成像技术（纤维追踪与3 T扩散张量纤维束成像）、相位对比成像和MRI兼容测力法以及有限元建模。巴勒斯坦权力机构要求进行“多学科研究”，“综合各种技术和生物医学领域的原则”，以“提供新的理解”和“有效地解决生物医学问题”。我们将通过实验研究几个设计特点的小腿三头肌复合体，可以解释目前的肌肉性能的描述明显的矛盾，并产生一个模型与我们的实验观察一致。我们的目标是更好地预测内在肌肉特性和关节性能。我们将测量以检验这些假设的基本变量包括肌肉体积、肌肉表面积、纤维方向、腱膜分离（肌肉厚度）、腱膜尺寸和腱膜的应变特性。在3Dal空间中，这些变量将在系统变化的踝关节位置和肌肉激活水平下进行量化。从NASA/NSBRI过去的资助中，我们在开发这些相对困难的技术方面取得了相当大的成功（根据附录中的出版物）。所开发的模型将有助于更好地了解肌肉-肌腱复合体的设计特征，更好地理解慢性肌肉适应，如废用性萎缩，以及更好地预测手术治疗的结果，如腱膜切开术，肌腱切除术和肌腱切断术。