Averaged properties of articular cartilage from multidisciplinary microscopic imaging study.

Most microscopic imaging techniques do not have the resolution to visualize individual collagen fibrils in articular cartilage, which possesses unique depth-dependent anisotropy and noticeable topographical heterogeneity. These imaging studies therefore deal with the averaged properties of the tissue. In this report, an ellipse model is introduced to explore the common connections between the anisotropic features of the tissue and the measurable quantities in several imaging techniques, including microscopic magnetic resonance imaging (µMRI), polarized light microscopy (PLM), and transmission electron microscopy (TEM). This model uses three quantities to represent the averaged properties of the tissue: the concentration ƿ that describes the density of the measurable property, the overall orientation Θ that describes the angular dependent features in the tissue, and the anisotropy Ɛ that describes the coherence of the measurable objects. We conclude that this ellipse model may serve as a useful platform to explore the common connections among different imaging results.