Scattering of light from histologic sections: a new method for the analysis of connective tissue

We have developed a light scattering technique that can be used to analyze the orientation and diameter of collagen fibers in histologic sections of connective tissue. Scattering patterns obtained by transmitting laser light through sections of tissue contain information both on the orientation, degree of alignment, and size of the constituent collagen fibers. Analysis of the azimuthal intensity distribution of scattered light yields numerical values of the degree of alignment by use of an orientation index, S, which is chosen to vary between 0 for randomly oriented fibers and 1 for a perfectly aligned arrangement. The average diameter of the collagen fibers is calculated from the scattering angle at which the intensity reaches its first minimum. These measurements are independent of the nature of histologic stain. The procedure is illustrated by measurements obtained with sections of the guinea pig dermis and of control scar. We conclude from our experiments that light scattering can complement the analysis of tissue architecture typically performed with the light microscope.