Automated Estimation of Collagen Fibre Dispersion in the Dermis and its Contribution to the Anisotropic Behaviour of Skin

TL;DR

This paper presents an automated, efficient method for estimating collagen fibre orientation in skin tissue, facilitating improved anisotropic modeling of soft tissues with minimal manual effort.

Contribution

It introduces a MATLAB-based algorithm that rapidly assesses collagen fibre dispersion from histological images, enhancing structural data collection for tissue modeling.

Findings

Strong correlation between Langer line orientation and collagen fibre direction

Successful evaluation of Gasser-Ogden-Holzapfel model parameters

Automated process reduces analysis time from hours to seconds

Abstract

Collagen fibres play an important role in the mechanical behaviour of many soft tissues. Modelling of such tissues now often incorporates a collagen fibre distribution. However, the availability of accurate structural data has so far lagged behind the progress of anisotropic constitutive modelling. Here, an automated process is developed to identify the orientation of collagen fibres using inexpensive and relatively simple techniques. The method uses established histological techniques and an algorithm implemented in the MATLAB image processing toolbox. It takes an average of 15 s to evaluate one image, compared to several hours if assessed visually. The technique was applied to histological sections of human skin with different Langer line orientations and a definite correlation between the orientation of Langer lines and the preferred orientation of collagen fibres in the dermis was observed. The structural parameters of the Gasser-Ogden-Holzapfel (GOH) model were all successfully evaluated. It is expected that the results of this study will assist those wishing to model skin, and that the algorithm described will be of benefit to those who wish to evaluate the collagen dispersion of other soft tissues.