Adaptive incremental method for strain estimation in phase-sensitive optical coherence elastography

Abstract

We proposed an adaptive incremental method for the cumulative strain estimation in phase-sensitive optical coherence elastography. The method firstly counts the amount of phase noise points by mapping a binary noise map. After the noise threshold value is preset, the interframe interval is adaptively adjusted in terms of the phase noise ratio. Finally, the efficient estimation of cumulative strain is implemented by reducing the cumulative number. Since the level of phase noise is related to the different strain rates in accordance with the speckle decorrelation, the proposed method can estimate the large strains with high computation efficiency as well as signal-to-noise ratio (SNR) enhancement in nonlinear change of sample deformations. Real experiments of visualizing polymerization shrinkage with nonlinear change of deformations were performed to prove the superiority of adaptive incremental method in estimating the large strains. The proposed method expands the practicability of the incremental method in more complex scenes.

Temporal phase evolution OCT for measurement of tissue deformation in the human retina in-vivo

“…While such method does not provide information on the elastic modulus (the force exerted on the tissue is unknown), it gives interesting insights on retinal tissue motion over the range of several seconds. In a further step, strain estimation could be performed based either on the LSM [ 18 ], as in heartbeat OCT [ 36 ], or the VM [ 19 ] and optimized VM [ 20 , 21 ].…”

“…The cumulative strain relative to the initial frame can finally be obtained by summation of the individual inter-frame data. The estimation of cumulative strain by such incremental method has been further optimized for slow rate tissue deformation imaging, as shown in recent studies [ 20 , 21 ]. In these works, rather than performing strain calculation for each pair of consecutive scans, the inter-frame time interval is adjusted according to the speed of the deformation.…”

Vector method of strain estimation in OCT-elastography with adaptive choice of scale for estimating interframe phase-variation gradients

“…In OCE, generically similar choosing of an appropriate interframe interval is required for the estimation of slowly varying deformations [8,9]. Estimation of such slowly varying strains is required for verification of stability of laserformed cartilaginous implants [10] or when studying osmotic deformations [11,12].…”

Adaptive selection of spatial scale to estimate axial gradients of inter-frame phase variations for mapping strains in optical coherence elastography

“…In OCE, estimation of the tissue strains is also based on comparison of sequentially obtained OCT scans, so that to improve the quality of strain-dynamics monitoring, an appropriate choice of interframe intervals is required. In particular, mapping of fairly slow deformations typical of relaxational and osmotic strains or polymerization processes requires the corresponding optimization of interframe time intervals 10,11 .…”