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- Time-dependent elastic numerical model for Optical Coherence Elastography of the murine retinaPublication . Correia, Carlos; Batista, Ana; Barbeiro, Sílvia; Cardoso, João; Domingues, José Paulo; Henriques, Rafael; Loureiro, Custódio; Santos, Mário J.; Serranho, Pedro; Bernardes, Rui; Morgado, MiguelWe present the initial stages of development of a Finite Element Method-based time-dependent elastic numerical model which seeks to support the employment of our Optical Coherence Elastography system for assessing murine retinal elasticity. The current model is able to reconstruct displacement maps in both homogeneous and heterogeneous domains with errors up to a few hundredths relatively to a known exact displacement map, within 1 millisecond. The results demonstrate the robustness of the numerical algorithm under different elastic domains, and model parametrization with real Optical Coherence Elastography data is already in progress.
- Swept-source phase-stabilized optical coherence tomography setup for elastographyPublication . Batista, Ana; Correia, Carlos; Barbeiro, Sílvia; Cardoso, João; Domingues, José Paulo; Henriques, Rafael; Loureiro, Custódio; Santos, Mário; Serranho, Pedro; Bernardes, Rui; Morgado, António MiguelWe present an Optical Coherence Elastography (OCE) system, based on a swept-source Optical Coherence Tomography (OCT) setup, and evaluate its performance in terms of phase stability and minimum detectable displacement. The ability to record sub-pixel movements in samples under dynamic conditions was also assessed. The OCE system has a time stability of 396.9 ± 46.7 ps. The phase stability, given by the standard deviation of the measured phase difference, was 72.44 mrad, which corresponds to a minimum detectable displacement of 6.11 nm. Tests showed that the OCE system can detect and measure sub-pixel movements in samples under dynamic mechanical excitation.
- On the numerical solution of the inverse elastography problem for time-harmonic excitationPublication . Serranho, Pedro; Barbeiro, Sílvia; Henriques, Rafael; Batista, Ana; Santos, Mário; Correia, Carlos; Domingues, José Paulo; Loureiro, Custódio; Cardoso, João M. R.; Bernardes, Rui; Morgado, António MiguelIn this paper we address the numerical solution of the inverse elastography problem, from the knowledge of the excitation field on the boundary and the displacement field in a grid of points within the domain. We suggest using a representation of the solution by the method of fundamental solutions and using a Newtontype method to iteratively approximate the Lam´e coefficients of the medium from elastography displacement measurements. We consider a toy model to illustrate the performance of the method.