Analysis of image formation in optical coherence elastography using a multiphysics approach

Lixin Chin; Andrea Curatolo; Brendan F Kennedy; Barry J Doyle; Peter R T Munro; Robert A McLaughlin; David D Sampson

doi:10.1364/BOE.5.002913

Analysis of image formation in optical coherence elastography using a multiphysics approach

Biomed Opt Express. 2014 Aug 1;5(9):2913-30. doi: 10.1364/BOE.5.002913. eCollection 2014 Sep 1.

Authors

Lixin Chin¹, Andrea Curatolo¹, Brendan F Kennedy², Barry J Doyle³, Peter R T Munro⁴, Robert A McLaughlin², David D Sampson⁴

Affiliations

¹ Optical + Biomedical Engineering Laboratory, School of Electrical, Electronic & Computer Engineering, The University of Western Australia, Crawley, Australia ; These authors contributed equally to this work.
² Optical + Biomedical Engineering Laboratory, School of Electrical, Electronic & Computer Engineering, The University of Western Australia, Crawley, Australia.
³ Vascular Engineering, Intelligent Systems for Medicine Laboratory, School of Mechanical & Chemical Engineering, The University of Western Australia, Crawley, Australia ; Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, UK.
⁴ Optical + Biomedical Engineering Laboratory, School of Electrical, Electronic & Computer Engineering, The University of Western Australia, Crawley, Australia ; Centre for Microscopy, Characterisation & Analysis, The University of Western Australia, Crawley, Australia.

Abstract

IMAGE FORMATION IN OPTICAL COHERENCE ELASTOGRAPHY (OCE) RESULTS FROM A COMBINATION OF TWO PROCESSES: the mechanical deformation imparted to the sample and the detection of the resulting displacement using optical coherence tomography (OCT). We present a multiphysics model of these processes, validated by simulating strain elastograms acquired using phase-sensitive compression OCE, and demonstrating close correspondence with experimental results. Using the model, we present evidence that the approximation commonly used to infer sample displacement in phase-sensitive OCE is invalidated for smaller deformations than has been previously considered, significantly affecting the measurement precision, as quantified by the displacement sensitivity and the elastogram signal-to-noise ratio. We show how the precision of OCE is affected not only by OCT shot-noise, as is usually considered, but additionally by phase decorrelation due to the sample deformation. This multiphysics model provides a general framework that could be used to compare and contrast different OCE techniques.

Keywords: (000.3860) Mathematical methods in physics; (000.4430) Numerical approximation and analysis; (030.6140) Speckle; (110.2990) Image formation theory; (110.4500) Optical coherence tomography.