Image processing techniques for quantitative analysis of skin structures

Computer-based image processing and analysis techniques were developed for quantitative analysis of skin structures in color histological sections. Pe rformance was compared with traditional non-image processing counting metho ds. Skin sections were stained with Masson's trichrome, hematoxylin and eos in, picrosirius red, or one of several elastin stains. The image processing software identified the top of the cellular epidermis and the dermal-epide rmal junction and then calculated the volume of the cellular layer of the e pidermis, epidermal thickness, and the ratio of the dermal-epidermal juncti on surface area to the in-plane surface area. It also identified cells and collagen and calculated cellular densities and collagen densities in the pa pillary and reticular layers of the dermis. Attempts to computationally pro cess elastin-stained sections to determine elastin density were unsuccessfu l. The described techniques were used in a preliminary study to compare mec hanically stressed skin with control skin. Results showed significant diffe rences in cellular density in the papillary dermis and collagen density in the reticular dermis for skin subjected to combined shear/compression or te nsion compared with an unstressed control. Measurements made with the compu ter technique and traditional technique showed comparable results; the mean difference in measurements for epidermal features was 5.33% while for derm al features it was 2.76%. Significance testing between control and experime ntal groups showed similar results, though for three of the 28 comparisons the computer method identified a significant difference while the tradition al method did not. The computer method took longer to conduct than the trad itional method, though with recent advances in computer hardware this time difference would be eliminated. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.