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The possibilities of using Mueller matrix (MM) imaging polarimetry to assess meat quality have not yet been sufficiently explored. In the current study, the fresh porcine muscles are imaged at room temperature with a wide‐field MM imaging polarimeter over 26 hours to visualize dynamics of tissue optical properties through applying Lu‐Chipman decomposition. The frequency distribution histograms (FDHs) and statistical analysis of the MM elements show prominent changes over time. The wavelength spectra of both total depolarization and scalar retardance have dips at 550 nm whereas their values continuously increase with time; the former is referred to the increase of number of scattering events and decrease of myoglobin absorption in the red part of visible spectra related to meat color and freshness, while the latter is associated with the increase in birefringence and meat tenderness. The obtained results are promising to develop a novel fast non‐contact optical technique for monitoring of meat quality.

We applied the wide-field Mueller imaging polarimetry for the screening of formalin-fixed paraffin-embedded samples of mouse brain tissue at different stages of brain β-amyloidosis in Alzheimer’s disease (AD). The accumulation of amyloid-beta (Aβ) deposits throughout the brain tissue is one of the key pathological hallmarks observed with the AD progression. We demonstrate that the presence of Aβ plaques influences the properties of backscattered polarized light, in particular, its degree of depolarization. By means of statistical analysis, we demonstrate that the high-order statistical moments of depolarization distributions, acquired with the multi-spectral Mueller imaging polarimetry, can be used as sensitive markers of the growing presence of Aβ plaques. The introduced label-free polarimetric approach has a potential to facilitate the current practice of the histopathology screening in terms of diagnosis accuracy, time and cost efficiency.

Alzheimer's disease, being a major societal burden, demands improvement of current techniques for its treatment and diagnostics. Currently only autopsy histology is able to provide the definite diagnosis for Alzheimer's disease. However, the procedure is rather time consuming and costly. In the current study, we utilized Stokes and Mueller polarimetry techniques to screen for amyloid-β (Aβ) deposits in formalin-fixed, paraffin-embedded mouse brain tissue at different stages of Alzheimer's disease. The study has shown that the presence of Aβ plaques influences the properties of scattered polarized light. The Poincaré sphere was used as a graphical tool for the visualization of the alterations of the Stokes vector, obtained with Stokes polarimetry, whereas statistical moments were used for the analysis of depolarization distributions that were acquired with Mueller polarimetry. We demonstrate the sensitivity of the last component of the Stokes vector, the degree of polarization and high-order statistical moments of depolarization to the structural alterations in brain tissue, which correspond to the disease progression. The described approach has a potential to improve the existing pathology screening methods and facilitates Aβ detection in AD research.

The possibilities of using Mueller matrix (MM) imaging polarimetry to assess meat quality have not yet been sufficiently explored. In the current study, the fresh porcine muscles are imaged at room temperature with a wide‐field MM imaging polarimeter over 26 hours to visualize dynamics of tissue optical properties through applying Lu‐Chipman decomposition. The frequency distribution histograms (FDHs) and statistical analysis of the MM elements show prominent changes over time. The wavelength spectra of both total depolarization and scalar retardance have dips at 550 nm whereas their values continuously increase with time; the former is referred to the increase of number of scattering events and decrease of myoglobin absorption in the red part of visible spectra related to meat color and freshness, while the latter is associated with the increase in birefringence and meat tenderness. The obtained results are promising to develop a novel fast non‐contact optical technique for monitoring of meat quality.

Mueller polarimetric imaging appeared to be very promising to detect the modifications in the microstructure of the uterine cervix due to the development of a precancerous lesion, thus providing very useful information for diagnostics to which practitioner cannot to access with classic color imaging. The first multispectral Mueller Polarimetric Colposcope (MPC) for the in vivo analysis of the uterine cervix will be presented. It has been obtained by miniaturizing a Mueller polarimetric imaging system and "grafting" it on a conventional colposcope, which is a low magnification binocular system, currently used in medical practice to examine the uterine cervix for detection of precancerous lesions. The multispectral MPC enables to obtain reliable Mueller polarimetric images in less than 2 seconds with a spatial resolution of 100 μm simultaneously at 450, 550 and 650 nm. Currently, it is being tested in vivo in the University Hospital of Kremlin Bicêtre in France. In order to evaluate the performance of the technique, polarimetric images need to be compared with histological analyses of biopsies. The procedure developed in collaboration with medical doctors to obtain an accurate correlation between polarimetric images and biopsies will be described., SCOPUS: cp.p, DecretOANoAutActif, info:eu-repo/semantics/published

Mueller polarimetry is increasingly recognized as a powerful modality in biomedical imaging. Nevertheless, principled statistical analysis procedures are still lacking in this field. This paper presents a complete pipeline for polarimetric bioimages, with an application to ex vivo cervical precancer detection. In the preprocessing stage, we evaluate the replacement of pixels by superpixels. In the analysis stage, we resort to decision theory to select and tune a classifier. Performances of the retained classifier are evaluated. Decision theory provides a rigorous and versatile framework, allowing generalization to other pathologies, to other imaging procedures, and to classification problems involving more than two classes., SCOPUS: ar.j, DecretOANoAutActif, info:eu-repo/semantics/published

Significant contrast in visible wavelength Mueller matrix images for healthy and pre-cancerous regions of excised cervical tissue is shown. A novel classification algorithm is used to compute a test statistic from a small patient population., SCOPUS: cp.p, info:eu-repo/semantics/published

Early detection through screening plays a major role in reducing the impact of cervical cancer on patients. When detected before the invasive stage, precancerous lesions can be eliminated with very limited surgery. Polarimetric imaging is a potential alternative to the standard screening methods currently used. In a previous proof-of-concept study, significant contrasts have been found in polarimetric images acquired for healthy and precancerous regions of excised cervical tissue. To quantify the ability of the technique to differentiate between healthy and precancerous tissue, polarimetric images of seventeen cervical conization specimens (cone-shaped or cylindrical wedges from the uterine cervix) are compared with results from histopathological diagnoses, which is considered to be the "gold standard." The sensitivity and specificity of the technique are calculated for images acquired at wavelengths of 450, 550, and 600 nm, aiming to differentiate between high-grade cervical intraepithelial neoplasia (CIN 2-3) and healthy squamous epithelium. To do so, a sliding threshold for the scalar retardance parameter was used for the sample zones, as labeled after histological diagnosis. An optimized value of ∼83% is achieved for both sensitivity and specificity for images acquired at 450 nm and for a threshold scalar retardance value of 10.6 deg. This study paves the way for an application of polarimetry in the clinic., SCOPUS: ar.j, info:eu-repo/semantics/published

The potential of Mueller matrix imaging polarimetry to become a new efficient technique for the optical biopsy and proper cancer staging was explored by measuring the exvivo samples of human tissues. Multi-spectral polarimetric images of both human colon and uterine cervix specimens reveal the enhanced contrasts between healthy and cancerous zones, compared to the unpolarized intensity images. For the understanding of physical origins of the observed polarimetric contrasts the Mueller matrix images of human colon tissue were simulated by Monte Carlo technique using multilayer optical model of tissue. The modeling results were compared with experimental data and confirmed that detected light is mainly backscattered by the objects small compared to the wavelength of probing light. The phenomenological model (decomposition of Mueller matrix into the product of elementary Mueller matrices of the homogeneous diattenuator, retarder, and depolarizer) was used for the quantitative characterization of the measured specimens in terms of their "effective" depolarization power, scalar birefringence and orientation of optical axis. The resulting polarimetric maps of the specimens were compared with the analysis of histological slides of corresponding specimen by anatomopathologists which is considered to be "gold-standard" in diagnostics. The general trends for depolarization and scalar birefringence values at different wavelengths confirmed the capability of Mueller polarimetry to differentiate between healthy and diseased tissue zones., SCOPUS: cp.p, info:eu-repo/semantics/published