With the development of optical coherence tomography,the application optical coherence elastography(OCE)has gained more and more attention in biomechanics for its unique features including micron-scale resolution,real...With the development of optical coherence tomography,the application optical coherence elastography(OCE)has gained more and more attention in biomechanics for its unique features including micron-scale resolution,real-time processing,and non-invasive imaging.In this review,one group of OCE techniques,namely dynamic OCE,are introduced and discussed including external dynamic OCE mapping and imaging of ex vivo breast tumor,external dynamic OCE measurement of in vivo human skin,and internal dynamic OCE including acoustomotive OCE and magnetomotive OCE.These techniques overcame some of the major drawbacks of traditional static OCE,and broadened the OCE application fields.Driven by scientific needs to engineer new quantitative methods that utilize the high micron-scale resolution achievable with optics,results of biomechanical properties were obtained from biological tissues.The results suggest potential diagnostic and therapeutic clinical applications.Results from these studies also help our understanding of the relationship between biomechanical variations and functional tissue changes in biological systems.展开更多
In this paper,we point out some practical obstacles arising in realization of compressional optical coherence elastography(OCE)that have not attracted sufficient attention previously.Specif-cally,we discuss(i)complica...In this paper,we point out some practical obstacles arising in realization of compressional optical coherence elastography(OCE)that have not attracted sufficient attention previously.Specif-cally,we discuss(i)complications in quantification of the Young modulus of tissues related to partial adhesion between the OCE probe and soft intervening reference layer sensor,(i)distorting influence of tisue suface curvature/corrugation on the subsurface strain distri-bution mapping,(ii)ways of signal-to-noise mtio(SNR)enhancement in OCE strain mapping when periodic averaging is not realized,and(iv)potentially significant infuence of tissue elastic nonlinearity on quantification of its stifness.Potential pnactical approaches to mitigate the effects of these complications are also described.展开更多
Characterizing nonhomogeneous elastic property distribution of soft tissues plays a crucial role in disease diagnosis and treatment.In this paper,we will apply the optical coherence elastography to reconstruct the she...Characterizing nonhomogeneous elastic property distribution of soft tissues plays a crucial role in disease diagnosis and treatment.In this paper,we will apply the optical coherence elastography to reconstruct the shear modulus elastic property distribution of a bilayer solid.In the computational aspect,we adopt a well-established inverse technique that solves for every nodal shear modulus in the problem domain(NO method).Additionally,we also propose a novel inverse method that assumes the shear moduli merely vary along the thickness of the bilayer solid(TO method).The inversion tests using simulated data demonstrate that TO method performs better in reconstructing the shear modulus distribution.Further,we utilize the experimental data obtained from the optical coherence tomography to reconstruct the shear modulus distribution of a bilayer phantom.We observe that the quality of the reconstructed shear modulus distribution obtained by the partial displacement measurement is better than that obtained by the full-field displacement measurement.Particularly,merely using the displacement component along the loading direction significantly improves the reconstructed results.This work is of great significance in applying optical coherence elastography(OCE)to characterize the elastic property distribution of layered soft tissues such as skins and corneas.展开更多
In the characterization of elastic properties of tissue using dynarmic optical coherence elasto-graphy,shear/surface waves are propagated and tracked in order to estimate speed and Y oung's modulus.However,for dis...In the characterization of elastic properties of tissue using dynarmic optical coherence elasto-graphy,shear/surface waves are propagated and tracked in order to estimate speed and Y oung's modulus.However,for dispersive tssues,the displacement pulse is highly damped and distorted during propagation,diminishing the ffectiveness of peak tracking approaches,and leading to biased cstimates of wave speed.Further,plane wave propagation is sometimes assumed,which contributes to estimation erors.Therefore,we invert a wave propagation model that incorpo-rates propagation,decay,and distortion of pulses in a dispersive media in order to accurately estimate its elastic and viscous components.The model uses a general first-order approximation of dispersion,avoiding the use of any particular rheological model of tisue.Experiments are conducted in elastic and viscoelastic tissue mimicking phantoms by producing a Gaussian push using acoustic radiation force excitation and measuring the wave propagation using a Fourier domain optical coherence tomography system.Results confirmed the ffectiveness of the inversion method in est imat ing viscoelastic parameters in both the viscoelastic and elastic phantoms when compared to mechanical measurements.Finally,the viscoelastic characterization of a fresh porcine comea was conducted.Preliminary results validate this approach when compared to other methods.展开更多
基金supported in part by grants from the National Institutes of Health(NIBIB,R21 EB005321,R01 EB005221,R01 EB009073NCI RC1 CA147096,S.A.B.).
文摘With the development of optical coherence tomography,the application optical coherence elastography(OCE)has gained more and more attention in biomechanics for its unique features including micron-scale resolution,real-time processing,and non-invasive imaging.In this review,one group of OCE techniques,namely dynamic OCE,are introduced and discussed including external dynamic OCE mapping and imaging of ex vivo breast tumor,external dynamic OCE measurement of in vivo human skin,and internal dynamic OCE including acoustomotive OCE and magnetomotive OCE.These techniques overcame some of the major drawbacks of traditional static OCE,and broadened the OCE application fields.Driven by scientific needs to engineer new quantitative methods that utilize the high micron-scale resolution achievable with optics,results of biomechanical properties were obtained from biological tissues.The results suggest potential diagnostic and therapeutic clinical applications.Results from these studies also help our understanding of the relationship between biomechanical variations and functional tissue changes in biological systems.
基金supported by the Russian Federation Government contract No.14.B25.31.0015supported by the Russian Foundation for Basic Research Grant No.16-02-00642Russian President grant for young scientists No.MK-6504.2016.2.
文摘In this paper,we point out some practical obstacles arising in realization of compressional optical coherence elastography(OCE)that have not attracted sufficient attention previously.Specif-cally,we discuss(i)complications in quantification of the Young modulus of tissues related to partial adhesion between the OCE probe and soft intervening reference layer sensor,(i)distorting influence of tisue suface curvature/corrugation on the subsurface strain distri-bution mapping,(ii)ways of signal-to-noise mtio(SNR)enhancement in OCE strain mapping when periodic averaging is not realized,and(iv)potentially significant infuence of tissue elastic nonlinearity on quantification of its stifness.Potential pnactical approaches to mitigate the effects of these complications are also described.
基金The authors acknowledge the support from the National Natural Science Foundation of China(12002075,11732004,12021002)the National Key Research and Development Plan(2020YFB1709401)+1 种基金the Foundation for Innovative Research Groups of the National Natural Science Foundation(11821202)the Natural Science Foundation of Liaoning Province in China(2021-MS-128).
文摘Characterizing nonhomogeneous elastic property distribution of soft tissues plays a crucial role in disease diagnosis and treatment.In this paper,we will apply the optical coherence elastography to reconstruct the shear modulus elastic property distribution of a bilayer solid.In the computational aspect,we adopt a well-established inverse technique that solves for every nodal shear modulus in the problem domain(NO method).Additionally,we also propose a novel inverse method that assumes the shear moduli merely vary along the thickness of the bilayer solid(TO method).The inversion tests using simulated data demonstrate that TO method performs better in reconstructing the shear modulus distribution.Further,we utilize the experimental data obtained from the optical coherence tomography to reconstruct the shear modulus distribution of a bilayer phantom.We observe that the quality of the reconstructed shear modulus distribution obtained by the partial displacement measurement is better than that obtained by the full-field displacement measurement.Particularly,merely using the displacement component along the loading direction significantly improves the reconstructed results.This work is of great significance in applying optical coherence elastography(OCE)to characterize the elastic property distribution of layered soft tissues such as skins and corneas.
文摘In the characterization of elastic properties of tissue using dynarmic optical coherence elasto-graphy,shear/surface waves are propagated and tracked in order to estimate speed and Y oung's modulus.However,for dispersive tssues,the displacement pulse is highly damped and distorted during propagation,diminishing the ffectiveness of peak tracking approaches,and leading to biased cstimates of wave speed.Further,plane wave propagation is sometimes assumed,which contributes to estimation erors.Therefore,we invert a wave propagation model that incorpo-rates propagation,decay,and distortion of pulses in a dispersive media in order to accurately estimate its elastic and viscous components.The model uses a general first-order approximation of dispersion,avoiding the use of any particular rheological model of tisue.Experiments are conducted in elastic and viscoelastic tissue mimicking phantoms by producing a Gaussian push using acoustic radiation force excitation and measuring the wave propagation using a Fourier domain optical coherence tomography system.Results confirmed the ffectiveness of the inversion method in est imat ing viscoelastic parameters in both the viscoelastic and elastic phantoms when compared to mechanical measurements.Finally,the viscoelastic characterization of a fresh porcine comea was conducted.Preliminary results validate this approach when compared to other methods.
