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

Abstract

.SignificanceParametric imaging of the attenuation coefficient μOCT using optical coherence tomography (OCT) is a promising approach for evaluating abnormalities in tissue. To date, a standardized measure of accuracy and precision of μOCT by the depth-resolved estimation (DRE) method, as an alternative to least squares fitting, is missing.AimWe present a robust theoretical framework to determine accuracy and precision of the DRE of μOCT.ApproachWe derive and validate analytical expressions for the accuracy and precision of μOCT 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.ResultsOur 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 μOCT2×Δ, where Δ is the pixel stepsize. When μOCT · | AFR | ≲ 1.8, μOCT is reconstructed with higher precision by the depth-resolved method compared to fitting over the length of an axial fitting range | AFR | .ConclusionsWe derived and validated expressions for the accuracy and precision of DRE of μOCT. 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.