Department of Physics, Norwegian University of Science and Technology, 7491 Trondheim, Norway.
IEEE Trans Med Imaging. 2011 Sep;30(9):1635-48. doi: 10.1109/TMI.2011.2139222. Epub 2011 Apr 7.
The 3-D morphology of chicken articular cartilage was quantified using multiphoton microscopy (MPM) for use in continuum-mechanical modeling. To motivate this morphological study we propose aspects of a new, 3-D finite strain constitutive model for articular cartilage focusing on the essential load-bearing morphology: an inhomogeneous, poro-(visco)elastic solid matrix reinforced by an anisotropic, (visco)elastic dispersed fiber fabric which is saturated by an incompressible fluid residing in strain-dependent pores. Samples of fresh chicken cartilage were sectioned in three orthogonal planes and imaged using MPM, specifically imaging the collagen fibers using second harmonic generation. Employing image analysis techniques based on Fourier analysis, we derived the principal directionality and dispersion of the collagen fiber fabric in the superficial layer. In the middle layer, objective thresholding techniques were used to extract the volume fraction occupied by extracellular collagen matrix. In conjunction with information available in the literature, or additional experimental testing, we show how this data can be used to derive a 3-D map of the initial solid volume fraction and Darcy permeability.
采用多光子显微镜（MPM）对鸡关节软骨的 3-D 形态进行定量分析，用于连续力学建模。为了推动这种形态学研究，我们提出了一种新的 3-D 有限应变本构模型的几个方面，该模型专注于基本的承载形态：由各向异性（粘弹性）分散纤维织物增强的不均匀、多孔（粘弹性）固体基质，其中充满了一种不可压缩的流体，这些流体位于依赖应变的孔中。新鲜鸡软骨样本在三个正交平面上进行切片，并使用 MPM 进行成像，特别是使用二次谐波产生来成像胶原蛋白纤维。我们采用基于傅立叶分析的图像分析技术，得出了在浅层中胶原蛋白纤维结构的主方向和分散度。在中层，采用客观阈值技术提取细胞外胶原蛋白基质所占据的体积分数。结合文献中提供的信息或其他实验测试，我们展示了如何使用这些数据来得出初始固体体积分数和达西渗透率的 3-D 图谱。
