Accuracy and precision of depth-resolved estimation of attenuation coefficients in optical coherence tomography

Significance: Parametric imaging of the attenuation coefficient mu(OCT) using optical coherence tomography (OCT) is a promising approach for evaluating abnormalities in tissue. To date, a standardized measure of accuracy and precision of mu(OCT) by the depth-resolved estimation (DRE) method, as an alternative to least squares fitting, is missing. Aim: We present a robust theoretical framework to determine accuracy and precision of the DRE of mu(OCT). Approach: We derive and validate analytical expressions for the accuracy and precision of mu(OCT) determination by the DRE using simulated OCT signals in absence and presence of noise. We compare the theoretically achievable precisions of the DRE method and the least-squares fitting approach. Results: Our analytical expressions agree with the numerical simulations for high signal-to-noise ratios and qualitatively describe the dependence on noise otherwise. A commonly used simplification of the DRE method results in a systematic overestimation of the attenuation coefficient in the order of mu(2)(OCT) x Delta, where Delta is the pixel stepsize. When mu(OCT) center dot |AFR| less than or similar to 1.8, mu(OCT) is reconstructed with higher precision by the depth-resolved method compared to fitting over the length of an axial fitting range |AFR|. Conclusions: We derived and validated expressions for the accuracy and precision of DRE of mu(OCT). A commonly used simplification of this method is not recommended as being used for OCT-attenuation reconstruction. We give a rule of thumb providing guidance in the choice of estimation method. (c) The Authors. Published by SPIE under a Creative Commons Attribution 4.0 International License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.