Second-harmonic generation imaging analysis can help distinguish sarcoidosis from tuberculoid leprosy

Advances in cellular and tissue-based imaging techniques for sarcoid granulomas

Sarcoidosis embodies a complex inflammatory disorder spanning multiple systems, with its origin remaining elusive. It manifests as the infiltration of inflammatory cells that coalesce into distinctive noncaseous granulomas within afflicted organs. Unraveling this disease necessitates the utilization of cellular or tissue-based imaging methods to both visualize and characterize the biochemistry of these sarcoid granulomas. Although hematoxylin and eosin stain, standard in routine use alongside cytological stains have found utility in diagnosis within clinical contexts, special stains such as Masson's trichrome, reticulin, methenamine silver, and Ziehl-Neelsen provide additional varied perspectives of sarcoid granuloma imaging. Immunohistochemistry aids in pinpointing specific proteins and gene expressions further characterizing these granulomas. Finally, recent advances in spatial transcriptomics promise to divulge profound insights into their spatial orientation and three-dimensional (3-D) molecular mapping. This review focuses on a range of preexisting imaging methods employed for visualizing sarcoid granulomas at the cellular level while also exploring the potential of the latest cutting-edge approaches like spatial transcriptomics and matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI), with the overarching goal of shedding light on the trajectory of sarcoidosis research.

The assessment of moderate acne vulgaris face skin using blood perfusion and hyperspectral imaging-A pilot study

BACKGROUND

Microcirculation is the flow of blood through the smallest vessels in the circulatory system. Capillaries respond to various pathologies much earlier than arteries and veins, the changes which indicate that the disease is already developing. Careful monitoring of the functioning of the capillary system often allows the detection of in vivo disorders at an early stage.

AIMS

The aim of the study was to evaluate the microcirculation within acne lesions. A noninvasive method of semi-quantitative blood perfusion measurement based on laser speckle contrast analysis (LASCA) and a quantitative assessment of the acne severity using the hyperspectral imaging method supported by image analysis and processing methods were used.

PATIENTS/METHOD

The acne lesion perfusion was compared to the healthy skin perfusion of the control group. The reflectance in the range from 400 to 1000 nm was also compared for acne lesions and healthy skin. A dedicated version of the algorithm based on the gray-level co-occurrence matrix was used to compare differences between acne lesions and healthy skin.

RESULTS

Blood perfusion in acne lesions is on average 117% higher than in healthy skin. The reflectance of acne lesions was lower in the range of 400-600 nm compared to the healthy skin. A statistically significant decrease in the reflectance of acne lesions was demonstrated for wavelengths: 434, 549, and 588 nm.

CONCLUSIONS

Increased blood perfusion in acne lesions compared to healthy skin suggests increased chemotaxis of inflammatory cells and wound healing. Decrease points in skin reflectance resemble the absorption peaks for hemoglobin and coproporphyrin III produced by Cutibacterium acnes. Thus, the proposed methods may serve not only for the early detection of acne lesions, before they manifest themselves clinically for the naked eye, but may also be a tool for quantifying the effectiveness of acne treatment.

Quantitative Evaluation of the Effectiveness of Chemical Peelings in Reducing Acne Lesions Based on Gray-Level Co-Occurrence Matrix (GLCM)

Purpose

Acne vulgaris is a chronic, inflammatory disease accompanied by lesions affecting the structure of the skin. Chemical peels are one of the methods of reducing acne vulgaris. There is still a lack of quantitative methods of assessing impact of cosmetic procedure on the skin. Skin condition depends on skin texture characterization; therefore, the analysis that provides data about the textures can be helpful in assessing the effectiveness of cosmetic treatments.

Patients and Methods

The study involved 24 volunteers with acne lesions. Each participant underwent 4 treatments using chemical peels at two-week intervals. Before, during and after procedure clinical photography were made. To assess effectiveness of chemical peeling in acne lesion reduction, we were used gray-level co-occurrence matrix (GLCM) analysis. Qualitative assessment of acne severity was made by 12 experts in dermatology.

Results

After a series of treatments, the GLCM contrast value decreased in each area of the face, and the GLCM homogeneity value increased, which means that the number of acne lesions was reduced. Expert assessment according to the IGA scale confirms the effectiveness of therapy with both salicylic and glycolic acid and pyruvic acid.

Conclusion

The results of this study prove that GLCM analysis is a useful tool for assessing the effectiveness of chemical peel treatments. It can also be used for quantitative assessment of skin texture.

Effects of the lower energy and pulse stacking in carbon dioxide laser skin treatment: an objective analysis using second harmonic generation

PURPOSE

To evaluate the effect of fractional carbon dioxide (CO2) laser treatment using lower power associated with pulse stacking within collagen fibers, using second harmonic generation microscopy and computerized image analysis.

METHODS

Twenty male Wistar rats aging eight weeks were used. Each treatment area received a single-pass CO2 fractional laser with different parameters. The 20 animals were divided into two groups and euthanized after 30 and 60 days. Second harmonic generation images were obtained and program ImageJ was utilized to evaluate the collagen organization within all areas. Collagen anisotropy, entropy and optical density were quantified.

RESULTS

Increased anisotropy over time was observed in all four areas, but only reached statistical significance (p = 0.0305) when the mildest parameters were used (area four). Entropy decreased over time in all areas, but without significance(p = 0.1779) in area four. Density showed an overtime increase only in area four, but no statistical significance was reached (p = 0.6534).

CONCLUSIONS

When combined, the results obtained in this study regarding anisotropy, entropy and density tend to demonstrate that it is possible to achieve collagen remodeling with the use of lower power levels associated with stacked pulses.