Characterization of anisotropic microstructure in biological tissues based on Stokes polarization imaging during dehydration process

Polarization is a non-invasive optical technique and has become an emerging new tool in biomedicine studies due to its sensitivity to microstructure. The development of fast polarization techniques has enabled the application of polarimetry not only include static samples such as pathological sections, but also contain dynamic samples such as the process of tissue optical clearing (TOC). Dehydration is one of the important mechanisms of TOC which can result in the changes in tissue anisotropy, samples with different structures will show different characteristics in dehydration. In this study, three kinds of tissues with different degree of anisotropic including skeletal muscle, skin and fat are employed. We extracted and compared the temporal polarization parameters of several samples which may be related to the properties of microstructures. Monte Carlo (MC) simulation was combined to further explore the relationship between temporal polarization parameters and anisotropy of the sample. We first verified the main mechanisms of dehydration in spherecylinder birefringence model (SCBM). Then the optical properties of the microstructure in the model were changed to explore their influence on the polarization parameters. By analyzing the polarization parameters extracted from temporal Stokes images and Monte Carlo simulation, we can present polarization parameters to characterize microstructures of biological tissues.