Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, USA.
Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, USA.
Biomech Model Mechanobiol. 2018 Aug;17(4):1119-1130. doi: 10.1007/s10237-018-1018-7. Epub 2018 Apr 19.
Mechanical modeling of tongue deformation plays a significant role in the study of breathing, swallowing, and speech production. In the absence of internal joints, fiber orientations determine the direction of sarcomeric contraction and have great influence over real and simulated tissue motion. However, subject-specific experimental observations of fiber distribution are difficult to obtain; thus, models of fiber distribution are generally used in mechanical simulations. This paper describes modeling of fiber distribution using solutions of Laplace equations and compares the effectiveness of this approach against tractography from diffusion tensor magnetic resonance imaging. The experiments included qualitative comparison of streamlines from the fiber model against experimental tractography, as well as quantitative differences between biomechanical simulations focusing in the region near the genioglossus. The model showed good overall agreement in terms of fiber directionality and muscle positioning when compared to subject-specific imaging results and the literature. The angle between the fiber distribution model against tractography in the genioglossus and geniohyoid muscles averaged [Formula: see text] likely due to experimental noise. However, kinematic responses were similar between simulations with modeled fibers versus experimentally obtained fibers; average discrepancy in surface displacement ranged from 1 to 7 mm, and average strain residual magnitude ranged from [Formula: see text] to 0.2. The results suggest that, for simulation purposes, the modeled fibers can act as a reasonable approximation for the tongue's fiber distribution. Also, given its agreement with the global tongue anatomy, the approach may be used in model-based reconstruction of displacement tracking and diffusion results.
舌变形的力学建模在呼吸、吞咽和言语产生的研究中起着重要作用。在缺乏内部关节的情况下，纤维方向决定了肌节收缩的方向，并对真实和模拟组织运动有很大的影响。然而，很难获得关于纤维分布的特定于个体的实验观察；因此，纤维分布模型通常用于力学模拟中。本文描述了使用拉普拉斯方程的解来建模纤维分布，并比较了这种方法与扩散张量磁共振成像的示踪法的有效性。实验包括将纤维模型中的流线与实验示踪法进行定性比较，以及对靠近颏舌肌区域的生物力学模拟进行定量差异比较。与特定于个体的成像结果和文献相比，该模型在纤维方向性和肌肉定位方面表现出良好的整体一致性。纤维分布模型与颏舌肌和颏舌骨肌中的示踪纤维之间的夹角平均为[Formula: see text]，可能是由于实验噪声。然而，模拟中使用建模纤维与实验获得纤维的运动学响应相似；表面位移的平均差异范围为 1 至 7 毫米，应变残余幅度的平均差异范围为[Formula: see text]至 0.2。结果表明，对于模拟目的，建模纤维可以作为舌纤维分布的合理近似。此外，鉴于其与整个舌解剖结构的一致性，该方法可用于基于模型的位移跟踪和扩散结果的重建。
