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

Abstract

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.

Combining Optical Coherence Tomography with Fluorescence Imaging

“…(3) at small depths. It is consistent with other group's report (Turchin et al, 2005), which expects for small depths:…”

“…The specimens were then washed in PBS, before being mounted and imaged by OCT/FMI system. Those models can be used to find the scattering coefficient µ s of the scattering media (Schmitt et al, 1993;Faber et al, 2004;Levitz et al, 2004;Turchin et al, 2005). Most recent models (Levitz et al, 2004;Turchin et al, 2005a) consider factors from the multi-scattering and the Gaussian beam propagation.…”

Optical coherence tomography in diagnosing inflammatory diseases of ENT

“…This complicates the interpretation of diagnostic OCT images and requires the development of algorithms for the numerical processing of OCT images to increase diagnostic accuracy of the technique. Such algorithms are usually based on the extraction of numerical parameters of the OCT images, such as individual optical properties of tissue layers [15], parameters of the histograms of entire OCT image [16] or preselected region of interest [17]. Extracted values can be sensitive to morphological alterations in cases when a clinician's visual perception is not able to distinguish changes.…”

“…Numerous studies have consistently proved that the pathological processes in biological tissues significantly change their optical properties, which can be sensed by OCT (see, for example, [15][16][17]). In this study it was possible to show that OCT could be used for diagnosis of inflammatory processes in ENT.…”

Optical coherence tomography—current technology and applications in clinical and biomedical research

“…Knüttel et al expanded Tearney's focus tracking method to measure depth-resolved changes of the refractive index [131]. Based on the model by Thrane et al relating the OCT signal strength to scattering [132], Letvitz et al extracted the scattering coefficient and the effective anisotropy factor from OCT A-scans [133], and Turchin et al developed an algorithm to derive the scattering coefficients of multi-layer samples [134]. Both methods aimed for the characterization of different pathologic states in tissue samples.…”