Properties Of Healthy Tissues Research Articles

Influence analysis of thermophysical properties on temperature profiles on the breast skin surface

This work presents a simplified approach for the early detection of breast cancer using thermographic images, showing that several thermophysical properties of the bio-thermal problem does not need to be previously known to locate the geometric center of tumors. A 3D hemispheric breast model composed of different layers (muscle, gland, fat and skin) was constructed to evaluate the thermal behavior on the skin surface from numerical simulations using commercial software COMSOL. The effects of changes in depth, size, metabolism, blood perfusion and thermal conductivity of the tumor at surface temperatures were systematically analyzed to provide important information and guidelines for future medical diagnoses. Variations in blood perfusions and thermal conductivities of healthy tissue layers were also evaluated. It has been found that changing the size, metabolism, blood perfusion and thermal conductivity of a centralized tumor in the same coordinate does not modify the profiles of normalized temperature variations on the breast skin surface. Regarding the properties of healthy tissue, if a specific region of the breast surface is taken, there is the possibility that the normalized temperature profiles also do not depend on these properties. Thus, knowing that one of the main limitations in the estimation of tumors from thermographic images is related to the difficulty of previously knowing the thermophysical properties of human tissues, the results obtained in this study provide valuable simplifications for the early diagnosis of breast cancer using infrared thermography.

Comparison of optical coherence tomography and histopathology in quantitative assessment of goat talus articular cartilage

Background and purpose — Optical coherence tomography (OCT) is a light-based imaging technique suitable for depiction of thin tissue layers such as articular cartilage. Quantification of results and direct comparison with a reference standard is needed to confirm the role of OCT in cartilage evaluation.Materials and methods — Goat talus articular cartilage repair was assessed quantitatively with OCT and compared with histopathology using semi-automated analysis software. Osteochondral defects were created centrally in goat tali with subsequent healing over 24 weeks. After sacrifice, the tali were analyzed using OCT and processed into histopathology slides. Cartilage thickness, repair tissue area, and surface roughness were measured. Also, light attenuation coefficient measurements were performed to assess differences in the properties of healthy tissue and repair tissue.Results — Intra-class correlation coefficients for resemblance between the 2 techniques were 0.95 (p < 0.001) for thickness, 0.73 (p = 0.002) for repair tissue area, and 0.63 (p = 0.015) for surface roughness. Light attenuation differed significantly between healthy cartilage (8.2 (SD 3.9) mm-1) and repair tissue (2.8 (SD 1.5) mm-1) (p < 0.001).Interpretation — Compared to histopathology as the standard reference method, OCT is a reproducible technique in quantitative analysis of goat talus articular cartilage, especially when assessing cartilage thickness and to a lesser extent when measuring repair tissue area and surface roughness. Moreover, differences in local light attenuation suggest measurable variation in tissue structure, enhancing the clinical applicability of quantitative measurements from cartilage OCT images.