Optical elastography and tissue biomechanics

Larin, Kirill V.; Scarcelli, Giuliano; Yakovlev, Vladislav V.

doi:10.1117/1.jbo.24.11.110901

Cited by 12 publications

(7 citation statements)

References 74 publications

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“… 11 , 12 Optical elastography techniques, including Brillouin microscopy and optical coherence elastography (OCE) have also been used to investigate corneal mechanical properties in vivo . 8 , 13 – 15 Brillouin microscopy is an exciting tool for assessing tissue mechanical properties. However, spatial mapping of the cornea is limited due to relatively long imaging times, and evaluating the relationship between the Brillouin modulus and Young’s modulus is still under investigation.…”

Section: Introductionmentioning

confidence: 99%

Heartbeat optical coherence elastography: corneal biomechanics in vivo

et al. 2021

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. Significance: Mechanical assessment of the cornea can provide important structural and functional information regarding its health. Current clinically available tools are limited in their efficacy at measuring corneal mechanical properties. Elastography allows for the direct estimation of mechanical properties of tissues in vivo but is generally performed using external excitation force. Aim: To show that heartbeat optical coherence elastography (Hb-OCE) can be used to assess the mechanical properties of the cornea in vivo. Approach: Hb-OCE was utilized to detect Hb-induced deformations in the rabbit cornea in vivo without the need for external excitation. Furthermore, we demonstrate how this technique can distinguish corneal stiffness between untreated (UT) and crosslinked (CXL) tissue. Results: Our results demonstrate that stiffness changes in the cornea can be detected using only the Hb-induced deformations in the cornea. Additionally, we demonstrate a statistically significant difference in strain between the UT and CXL corneas. Conclusions: Hb-OCE may be an effective tool for assessing the mechanical properties of the cornea in vivo without the need for external excitation. This tool may be effective for clinical assessment of corneal mechanical properties because it only requires optical coherence tomography imaging and data processing.

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Section: Introductionmentioning

confidence: 99%

Heartbeat optical coherence elastography: corneal biomechanics in vivo

et al. 2021

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“…Optical coherence elastography (OCE) is an established field that allows for quantitative viscoelastic characterization of tissues with the micrometer-scale resolution. 13 – 16 In particular, wave-based OCE, which leverages the propagation of mechanical waves for imaging mechanical contrast of soft tissues, has proven to be a useful technique for noninvasive elastography of the eye in a wide variety of applications. 17 However, OCE of the eye has been mostly concentrated on the central cornea.…”

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confidence: 99%

Dynamic Optical Coherence Elastography of the Anterior Eye: Understanding the Biomechanics of the Limbus

Zvietcovich

Nair

Singh

et al. 2020

Invest. Ophthalmol. Vis. Sci.

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Purpose Currently, the biomechanical properties of the corneo-scleral limbus when the eye-globe deforms are largely unknown. The purpose of this study is to evaluate changes in elasticity of the cornea, sclera, and limbus when subjected to different intraocular pressures (IOP) using wave-based optical coherence elastography (OCE). Special attention was given to the elasticity changes of the limbal region with respect to the elasticity variations in the neighboring corneal and scleral regions. Methods Continuous harmonic elastic waves (800 Hz) were mechanically induced in the sclera near the corneo-sclera limbus of in situ porcine eye-globes ( n = 8). Wave propagation was imaged using a phase-sensitive optical coherence tomography system (PhS-OCT). The eyes were subjected to five different IOP-levels (10, 15, 20, 30, and 40 mm Hg), and spatially distributed propagation velocities were calculated along corneal, limbal, and scleral regions. Finite element analysis (FEA) of the same regions under the same excitation conditions were conducted for further validation of results. Results FEA demonstrated that the stiffness of the heterogeneous cornea-limbus-sclera transition can be characterized by phase velocity measurements of the elastic waves produced at 800 Hz in the anterior eye. Experimental results revealed that the wave speed in the limbus ( c L = 6.5 m/s) is between the cornea ( c c = 2.9 m/s) and sclera ( c s = 10.0 m/s) at a physiological IOP level (15 mm Hg) and rapidly increases as the IOP level is increased, even surpassing the wave speed in the sclera. Finally, the change in elastic wave speed in the limbus (Δ c L ∼18.5 m/s) was greater than in the cornea (Δ c c ∼12.6 m/s) and sclera (Δ c s ∼8.1 m/s) for the same change in IOP. Conclusions We demonstrated that wave-based OCE can be utilized to assess limbus biomechanical properties. Moreover, experimental evidence showed that the corneo-scleral limbus is highly nonlinear compared to the cornea and sclera when the eye-globe is deformed by an increase of IOP. This may suggest that the limbus has enough structural flexibility to stabilize anterior eye shape during IOP changes.

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“…Several optical elastography methods have been proposed, such as Optical Coherence Elastography (OCE), Brillouin Microscopy, digital holography, laser speckle, and ultrasound-modulated optical tomography. For smaller-length scale samples in the range of 100 μm or less, multiple microrheology techniques have been proposed, such as passive microrheology, active microrheology, dynamic light scattering, diffusive wave spectroscopy, and optical tweezers. − …”

Section: Viscoelasticity Measurement Techniques For In Vitro and Ex V...mentioning

confidence: 99%

Viscoelasticity in 3D Cell Culture and Regenerative Medicine: Measurement Techniques and Biological Relevance

Eliahoo,

Setayesh,

Hoffman

et al. 2024

ACS Mater. Au

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The field of mechanobiology is gaining prominence due to recent findings that show cells sense and respond to the mechanical properties of their environment through a process called mechanotransduction. The mechanical properties of cells, cell organelles, and the extracellular matrix are understood to be viscoelastic. Various technologies have been researched and developed for measuring the viscoelasticity of biological materials, which may provide insight into both the cellular mechanisms and the biological functions of mechanotransduction. Here, we explain the concept of viscoelasticity and introduce the major techniques that have been used to measure the viscoelasticity of various soft materials in different length-and timescale frames. The topology of the material undergoing testing, the geometry of the probe, the magnitude of the exerted stress, and the resulting deformation should be carefully considered to choose a proper technique for each application. Lastly, we discuss several applications of viscoelasticity in 3D cell culture and tissue models for regenerative medicine, including organoids, organ-on-a-chip systems, engineered tissue constructs, and tunable viscoelastic hydrogels for 3D bioprinting and cell-based therapies.

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Optical elastography and tissue biomechanics

Cited by 12 publications

References 74 publications

Heartbeat optical coherence elastography: corneal biomechanics in vivo

Heartbeat optical coherence elastography: corneal biomechanics in vivo

Dynamic Optical Coherence Elastography of the Anterior Eye: Understanding the Biomechanics of the Limbus

Viscoelasticity in 3D Cell Culture and Regenerative Medicine: Measurement Techniques and Biological Relevance

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