Analysis of attenuation coefficient estimation in Fourier-domain OCT of semi-infinite media

Abstract

The attenuation coefficient (AC) is an optical property of tissue that can be estimated from optical coherence tomography (OCT) data. In this paper, we aim to estimate the AC accurately by compensating for the shape of the focused beam. For this, we propose a method to estimate the axial PSF model parameters and AC by fitting a model for an OCT signal in a homogenous sample to the recorded OCT signal. In addition, we employ numerical analysis to obtain the theoretical optimal precision of the estimated parameters for different experimental setups. Finally, the method is applied to OCT B-scans obtained from homogeneous samples. The numerical and experimental results show accurate estimations of the AC and the focus location when the focus is located inside the sample.

Precision of attenuation coefficient measurements by optical coherence tomography

“…A Cramér–Rao analysis for the parameter set representative for ophthalmic OCT systems was previously reported in Ref. 23 , using the same signal model as in the present manuscript. Before the analysis, the signal is already noise corrected.…”

“…This averaged amplitude, in general, follows an unspecified distribution different from the Rayleigh distribution. However, with a sufficient number of averages , the averaged amplitudes at each depth can be adequately characterized by a normal distribution , 23 which we will assume henceforth.…”

“…In this article, we used parameter values that are typically encountered in OCT measurements in dermatology or urology. A Cramér–Rao analysis for ophthalmic applications was recently given by Ghafaryasl et al., 23 albeit with some procedural mistakes. The result of our Cramér–Rao analysis using the system parameters in Ref.…”

“…The result of our Cramér–Rao analysis using the system parameters in Ref. 23 can be found in Appendix D . Promising clinical applications include spectroscopic OCT, 28 where the attenuation coefficient is measured at multiple wavelengths to determine, e.g., oxygen saturation 29 and hemoglobin concentration.…”

Attenuation corrected‐optical coherence tomography for quantitative assessment of skin wound healing and scar morphology

“…A number of studies have incorporated SS models for estimating OAC in skin tissues [63, 64]. A most recent addition to the single scattering model includes estimation of axial PSF (point spread function) model parameters and determining attenuation coefficient for homogeneous samples [65]. However, its utility in heterogeneous tissues is yet to be established.…”