Optical coherence tomography (OCT) is a promising tool for intraoperative tissue morphology determination. Several studies suggest that attenuation coefficient derived from the OCT images, can differentiate between tissues of different morphology, such as normal and pathological structures of the brain, skin and other tissues. In the present study, the depth‐resolved method for attenuation coefficient calculation was adopted for the real‐world situation of the depth‐dependent OCT sensitivity and additive imaging noise with non‐zero mean. It was shown that in the case of sharp focusing (~10 μm spot full width at half maximum (FWHM) or smaller at 1.3 μm central wavelength) only the proposed method for depth‐dependent sensitivity compensation does not introduce misleading artifacts into the calculated attenuation coefficient distribution. At the same time, the scanning beam focus spot with FWHM greater than 10 μm at 1.3 μm central wavelength allows one to use multiple approaches to the attenuation coefficient calculation without introducing noticeable bias. This feature may hinder the need for robust corrections for the depth‐resolved attenuation coefficient estimations from the community.This article is protected by copyright. All rights reserved.

A pilot post-mortem study identifies a strong correlation between the attenuation coefficient estimated from the OCT data and some morphological features of the sample, namely the number of nuclei in the field of view of the histological image and the fiber structural parameter introduced in the study to quantify the difference in the myelinated fibers arrangements. The morphological features were identified from the histopathological images of the sample taken from the same locations as the OCT images and stained with the immunohistochemical (IHC) staining specific to the myelin. It was shown that the linear regression of the IHC quantitative characteristics allows adequate prediction of the attenuation coefficient of the sample. This discovery opens the opportunity for the usage of the OCT as a neuronavigation tool.

We present an improved analytical model of a spectrometer for optical coherence tomography (OCT), which more accurately describes the OCT in-depth sensitivity fall-off. The model considers the intrinsic spectral resolution of the dispersive element and the influence of additional components (inequidistance-correcting prism). The model is validated by experimental data obtained both from other studies and our own experiments. The influence of the frequency response of the CCD electrical circuit and the analog-to-digital converter to the OCT signal fall-off was also detected and was shown to be significant in some cases.

Attenuation coefficient estimation from optical coherent tomography (OCT) data is one of the emerging methods for additional information extraction from the OCT data. With the reasonable assumptions of uniform proportion of the light, scattered backwards, relative to the light, scattered in all directions and the assumption of complete light attenuation within the imaging depth range, the attenuation coefficient can be estimated in every pixel of the OCT data volume, i.e. with the depth resolution. In the present paper the numerically effective method for lifting the second assumption was proposed. With numerical simulations and experiments it was shown, that the proposed method allows attenuation coefficient estimation even if OCT signal was not completely attenuated within the imaging depth range. Since the proposed method lifts one of the requirements for depth-resolved attenuation coefficient estimation, it allows the extension of the depth-resolved attenuation estimation method to the new applications.