A model for simulating speckle-pattern evolution based on close to reality procedures used in spectral-domain OCT

Zaitsev, Vladimir Yu.; Matveev, Lev A.; Matveyev, Alexander L.; Gelikonov, Grigory V.; Gelikonov, Valentin M.

doi:10.1088/1612-2011/11/10/105601

Cited by 52 publications

(78 citation statements)

References 26 publications

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“…5(b) and 5(d) show rigorously simulated (using model of Ref. 33) 2D phase-variation diagrams for strains " $ 10 À3 and " $ 5 Á 10 À3 in a two-layer sample with 50% contrast in sti®ness. The simulation parameters correspond to a typical OCT system operating at 1300 nm with spectral width $100 nm, and the \decorrelation noise" due to displacements of scatterers is also reproduced in the simulation, although it is not yet very signi¯-cant for such strains.…”

Section: Enhancing Snr In Compressional Oce When Periodic Averaging Imentioning

confidence: 99%

Practical obstacles and their mitigation strategies in compressional optical coherence elastography of biological tissues

Zaitsev

Matveyev

Matveev

et al. 2017

J. Innov. Opt. Health Sci.

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In this paper, we point out some practical obstacles arising in realization of compressional optical coherence elastography (OCE) that have not attracted su±cient attention previously. Speci¯-cally, we discuss (i) complications in quanti¯cation of the Young modulus of tissues related to partial adhesion between the OCE probe and soft intervening reference layer sensor, (ii) distorting in°uence of tissue surface curvature/corrugation on the subsurface strain distribution mapping, (iii) ways of signal-to-noise ratio (SNR) enhancement in OCE strain mapping when periodic averaging is not realized, and (iv) potentially signi¯cant in°uence of tissue elastic nonlinearity on quanti¯cation of its sti®ness. Potential practical approaches to mitigate the e®ects of these complications are also described.

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Section: Enhancing Snr In Compressional Oce When Periodic Averaging Imentioning

confidence: 99%

Practical obstacles and their mitigation strategies in compressional optical coherence elastography of biological tissues

Zaitsev

Matveyev

Matveev

et al. 2017

J. Innov. Opt. Health Sci.

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show abstract

“…To demonstrate phase comparison for complex-valued OCT scans suitable for suprapixel displacements of scatterers, we use our model 29 according to which complex-valued amplitudes of pixels in a one-dimensional (1-D) A-scan formed by spectraldomain OCT can be written as follows:…”

Section: Phase Comparison For Supra-pixel Displacements Between Nativmentioning

confidence: 99%

“…3 describes the speckle-pattern evolution in OCT images of deformed tissues. 29 Equation 1of the present paper with N ¼ 256 spectral components was used to generate B-scans containing 256 A-scans with input experimental system parameters, to compare directly with real OCT images of the left panels of Fig. 3; the optical and mechanical phantom properties used in the simulation also correspond to the experiment.…”

Section: Apparent Stiff Inclusion Artifacts Nearmentioning

confidence: 99%

Optimized phase gradient measurements and phase-amplitude interplay in optical coherence elastography

et al. 2016

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In compressional optical coherence elastography, phase-variation gradients are used for estimating quasistatic strains created in tissue. Using reference and deformed optical coherence tomography (OCT) scans, one typically compares phases from pixels with the same coordinates in both scans. Usually, this limits the allowable strains to fairly small values <10?4 to 10?3, with the caveat that such weak phase gradients may become corrupted by stronger measurement noises. Here, we extend the OCT phase-resolved elastographic methodology by (1) showing that an order of magnitude greater strains can significantly increase the accuracy of derived phase-gradient differences, while also avoiding error-phone phase-unwrapping procedures and minimizing the influence of decorrelation noise caused by suprapixel displacements, (2) discussing the appearance of artifactual stiff inclusions in resultant OCT elastograms in the vicinity of bright scatterers due to the amplitude-phase interplay in phase-variation measurements, and (3) deriving/evaluating methods of phase-gradient estimation that can outperform conventionally used least-square gradient fitting. We present analytical arguments, numerical simulations, and experimental examples to demonstrate the advantages of the proposed optimized phase-variation methodology.

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“…The simulation results that follow are based on a model of OCT image formation that is described in detail previously 10 and is briefly summarized here. To generate the speckle patterns, the model reproduces the main steps of image formation in real spectral-domain OCT systems, in which the scans are constructed by superposing a set of optical spectral components (typically several hundreds) ballistically scattered from tissue.…”

Section: Model Of Image Formation Based Onmentioning

confidence: 99%

Deformation-induced speckle-pattern evolution and feasibility of correlational speckle tracking in optical coherence elastography

et al. 2015

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Feasibility of speckle tracking in optical coherence tomography (OCT) based on digital image correlation (DIC) is discussed in the context of elastography problems. Specifics of applying DIC methods to OCT, compared to processing of photographic images in mechanical engineering applications, are emphasized and main complications are pointed out. Analytical arguments are augmented by accurate numerical simulations of OCT speckle patterns. In contrast to DIC processing for displacement and strain estimation in photographic images, the accuracy of correlational speckle tracking in deformed OCT images is strongly affected by the coherent nature of speckles, for which strain-induced complications of speckle “blinking” and “boiling” are typical. The tracking accuracy is further compromised by the usually more pronounced pixelated structure of OCT scans compared with digital photographic images in classical DIC applications. Processing of complex-valued OCT data (comprising both amplitude and phase) compared to intensity-only scans mitigates these deleterious effects to some degree. Criteria of the attainable speckle tracking accuracy and its dependence on the key OCT system parameters are established.

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A model for simulating speckle-pattern evolution based on close to reality procedures used in spectral-domain OCT

Cited by 52 publications

References 26 publications

Practical obstacles and their mitigation strategies in compressional optical coherence elastography of biological tissues

Practical obstacles and their mitigation strategies in compressional optical coherence elastography of biological tissues

Optimized phase gradient measurements and phase-amplitude interplay in optical coherence elastography

Deformation-induced speckle-pattern evolution and feasibility of correlational speckle tracking in optical coherence elastography

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