Share Email Print
cover

Proceedings Paper

Optimization of phase-variation measurements in low-coherence methods: implications for OCE
Author(s): Vladimir Yu. Zaitsev; Alexandr L. Matveyev; Lev A. Matveev; Grigory V. Gelikonov; Alexander A. Sovetsky; Alex Vitkin
Format Member Price Non-Member Price
PDF $14.40 $18.00

Paper Abstract

Phase-resolved measurements found numerous applications in low-coherence methods, in particular in OCT-based compressional elastography, where phase-variation gradients are used for estimating strains produced by the OCT probe pressed onto the tissue. Conventionally, for the reference and deformed pixelated OCT scans, one performs comparison of phases taken from pixels with the same coordinates. This is reasonable in regions of sufficiently small sub-pixel displacements, for which the so-compared pixels contain the same scatterers. Furthermore, to avoid error-prone multiple phase unwrapping for reconstructing displacements, one have to ensure even smaller sub-wavelength displacements. This limits the allowable strains to less than ~10-4-10-3, although such weak phase gradients can be strongly corrupted by measurement noises. Here, we discuss how creation of an order of magnitude greater strains can be used for increasing the signal-to noise ratio in estimating phase gradients by obviating the phase-unwrapping procedures and reducing the influence of decorrelation noise for supra-pixel displacements. This optimized phase-variation measurement makes it possible to perform strain mapping in optical coherence elastography with exceptionally high tolerance to noises due to possibility of using significantly increased strains. We also discuss the effect of “frozen-phase zones” associated with displaced strong scatterers. This effect can result in appearance of artifacts in the form of false stiff inclusions in elastograms in the vicinity of bright scatterers in OCT scans. We present analytical arguments, numerical simulations and experimental examples illustrating the above-mentioned features of the “frozen-phase” effect and advantages of using the proposed optimized phase-variation measurement with pixel-scale displacement compensation in the compared OCT scans.

Paper Details

Date Published: 27 April 2016
PDF: 12 pages
Proc. SPIE 9887, Biophotonics: Photonic Solutions for Better Health Care V, 98871G (27 April 2016); doi: 10.1117/12.2228093
Show Author Affiliations
Vladimir Yu. Zaitsev, Institute of Applied Physics of the RAS (Russian Federation)
Nizhny Novgorod State Medical Academy (Russian Federation)
State Univ. of Nizhny Novgorod (Russian Federation)
Alexandr L. Matveyev, Institute of Applied Physics of the RAS (Russian Federation)
Nizhny Novgorod State Medical Academy (Russian Federation)
Lev A. Matveev, Institute of Applied Physics of the RAS (Russian Federation)
Nizhny Novgorod State Medical Academy (Russian Federation)
Grigory V. Gelikonov, Institute of Applied Physics of the RAS (Russian Federation)
Nizhny Novgorod State Medical Academy (Russian Federation)
Alexander A. Sovetsky, State Univ. of Nizhny Novgorod (Russian Federation)
Alex Vitkin, Nizhny Novgorod State Medical Academy (Russian Federation)
Univ. of Toronto (Canada)


Published in SPIE Proceedings Vol. 9887:
Biophotonics: Photonic Solutions for Better Health Care V
Jürgen Popp; Valery V. Tuchin; Dennis L. Matthews; Francesco Saverio Pavone, Editor(s)

© SPIE. Terms of Use
Back to Top