Mueller matrix polarimetry and polar decomposition of articular cartilage imaged in reflectance

Abstract

Articular cartilage birefringence relates to zonal architecture primarily of type II collagen, which has been assessed extensively in transmission, through thin tissue sections, to evaluate cartilage repair and degeneration. Mueller matrix imaging of articular cartilage in reflection is of potential utility for non-destructive imaging in clinical and research applications. Therefore, such an imaging system was constructed to measure laser reflectance signals, calibrated, and tested with optical standards. Polar decomposition was chosen as a method to extract fundamental optical parameters from the experimental Mueller matrices, with performance confirmed by simulations. Adult bovine articular cartilage from the patellofemoral groove was found to have ∼0.93 radians retardance, low diattenuation of ∼0.2, and moderately high depolarization of 0.66. Simulations showed that variation in depolarization drives inaccuracy of depolarization and retardance maps derived by polar decomposition. These results create a basis for further investigation of the clinical utility of polarized signals from knee tissue and suggest potential approaches for improving the accuracy of polar decomposition maps.

Full Poincaré Mueller Polarimetry Using a Ccd Camera

“…Similar levels of the rms value (0.0018) have been found for air as a calibration sample for a Mueller matrix polarimeter that uses a similar PSA to that in the present experiment [42]. For a Mueller matrix polarimeter with a PSA made up of a rotating QWP or dual-rotating retarders and a linear polarizer, rms values on the order of 0.004-0.04 or even higher have been reported for air and phase wave-plates as samples [11,16,43,44]. For Mueller matrix polarimeters using photoelastic modulators or liquid-crystal variable retarders, the rms of the difference between the measured Mueller matrix and the expected ones in the range 0.006-0.028 has been found [22,23].…”

“…Sample polarimetry is a non-invasive technique to determine the linear optical behavior of an unknown sample [1][2][3]. This behavior is related to the sample composition, structure, thickness, surface roughness, etc, and its knowledge is very useful in many different areas, such as medical diagnostic techniques [4][5][6][7][8][9][10][11], technological materials characterization and fabrication control [2,[12][13][14][15][16][17], identification and counting of microplastics in wastewater [18] or air pollution detection [19][20][21]. Many different Mueller matrix polarimetric techniques have been developed up to now (see, for example, [1,2,10,[22][23][24]).…”

Reciprocal polarization imaging of complex media

“…In all cases, the polarization properties of complex media determined by the reciprocal polar decomposition of the backscattering Mueller matrices are in excellent agreement with those obtained by polarization imaging of the same sample in the forward geometry. Furthermore, when light depolarization (∆) is elevated, the accuracy of recovered media polarization parameters deteriorates from polarization imaging [22]. The performance of reciprocal polar decomposition for complex media of high depolarization warrants further study and will be published later.…”

Spectral imaging of normal, hydrated, and desiccated porcine skin using polarized light

“…Polarized spectral imaging is a technique capable of distinguishing deeply scattered photons and superficially scattered photons at multiple wavelengths. [9][10][11][12][13][14] The population of photons scattered by only one or a few scattering events from superficial tissue layers, the subdiffuse scatter, partially retains the orientation of the incident polarized light. The population of multiply scattered photons backscattered from the deeper tissue is depolarized.…”