Novel algorithm of processing optical coherence tomography images for differentiation of biological tissue pathologies

A numerical algorithm based on a small- angle approximation of the radiative transfer equation ( RTE ) is developed to reconstruct scattering characteristics of biological tissues from optical coherence tomography ( OCT ) images. According to the algorithm, biological tissue is considered to be a layered random medium with a set of scattering parameters in each layer: total scattering coefficient, variance of a small- angle scattering phase function, and probability of backscattering, which fully describe the OCT signal behavior versus probing depth. The reconstruction of the scattering parameters is performed by their variation to fit the experimental OCT signal by the theoretical one using a time- saving genetic algorithm. The proposed reconstruction procedure is tested on model media with known scattering parameters. The possibility to estimate scattering parameters from OCT images is studied for various regimes of OCT signal decay. The developed algorithm is applied to reconstruct optical characteristics of epithelium and stroma for normal cervical tissue and its pathologies, and the potential to distinguish between the types of pathological changes in epithelial tissue by its OCT images is demonstrated. (C) 2005 Society of Photo- Optical Instrumentation Engineers.