A visualization of nonlinear elasticity property of tissues by ultrasound

Nitta, Naotaka; Shiina, Tsuyoshi

doi:10.1002/ecjc.10024

Cited by 12 publications

(8 citation statements)

References 6 publications

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“…In this study, homogeneous and isotropic silicone phantoms were fabricated so as to simplify the mechanical behavior of the specimen. The stiffness coefficient or Young’s modulus was obtained with the constraint of 3% of the deformation/thickness ratio or strain, which was thought to be a linear elasticity region for most soft tissues [49]. The viscosity was neglected in the study because it was not so obviously observed for the silicone phantoms fabricated in this study.…”

Section: Discussionmentioning

confidence: 99%

“…We assumed homogeneity of the compressive properties of the phantom, so one value of Young’s modulus would represent all at each specific point. The deformation ratio (deformation/initial thickness) or strain was constrained to be within 3% in all the calculations in order to obtain a coefficient within the linear elasticity region of compression of the phantoms [49]. Due to low viscosity of the silicone phantoms, data of both the loading and unloading processes were utilized for the calculation of the stiffness coefficient.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

An optical coherence tomography (OCT)-based air jet indentation system for measuring the mechanical properties of soft tissues

Zheng

Wang

Chen

et al. 2008

Meas. Sci. Technol.

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A novel noncontact indentation system with the combination of an air jet and optical coherence tomography (OCT) was presented in this paper for the quantitative measurement of the mechanical properties of soft tissues. The key idea of this method is to use a pressure-controlled air jet as an indenter to compress the soft tissue in a noncontact way and utilize the OCT signals to extract the deformation induced. This indentation system provides measurement and mapping of tissue elasticity for small specimens with high scanning speed. Experiments were performed on 27 silicone tissue-mimicking phantoms with different Young’s moduli, which were also measured by uniaxial compression tests. The regression coefficient of the indentation force to the indentation depth (N mm−1) was used as an indicator of the stiffness of tissue under air jet indentation. Results showed that the stiffness coefficients measured by the current system correlated well with the corresponding Young’s moduli obtained by conventional mechanical testing (r = 0.89, p < 0.001). Preliminary in vivo tests also showed that the change of soft tissue stiffness with and without the contraction of the underlying muscles in the hand could be differentiated by the current measurement. This system may have broad applications in tissue assessment and characterization where alterations of mechanical properties are involved, in particular with the potential of noncontact micro-indentation for tissues.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

An optical coherence tomography (OCT)-based air jet indentation system for measuring the mechanical properties of soft tissues

Zheng

Wang

Chen

et al. 2008

Meas. Sci. Technol.

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“…Within this strain range, a linear elasticity for most soft tissues could be assumed [30]. A force of 0.04 N was used as a preload for extracting the stiffness coefficient.…”

Section: Discussionmentioning

confidence: 99%

“…The stiffness coefficient was calculated by a linear regression of the force-deformation curve of the indentation in the loading phase [23]. Only the data within a 3% strain level [30] were adopted to obtain the curve-fitted stiffness for all the three indentations. Because the stiffness coefficient was obtained under specific experimental conditions used in this study, that is, the selected indentation speed, air-jet diameter, applied deformation and reflected the mechanical property of the whole cartilage layer, it should be interpreted as "apparent stiffness", considering that cartilage is viscoelastic, inhomogeneous, and anisotropic [24].…”

Section: Parameters Calculation and Statistical Analysismentioning

confidence: 99%

Quantification of Stiffness Change in Degenerated Articular Cartilage Using Optical Coherence Tomography-Based Air-Jet Indentation

Huang

Wang

Saarakkala

et al. 2011

Connective Tissue Research

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Articular cartilage is a thin complex tissue that covers the bony ends of joints. Changes in the composition and structure of articular cartilage will cause degeneration, which may further lead to osteoarthritis. Decreased stiffness is one of the earliest symptoms of cartilage degeneration and also represents the imperfect quality of repaired cartilage. An optical coherence tomography (OCT)-based air-jet indentation system was recently developed in our group to measure the mechanical properties of soft tissues. In this study, this system was applied to quantify the change of mechanical properties of articular cartilage after degeneration induced by enzymatic digestions. Forty osteochondral disks (n = 20 × 2) were prepared from bovine patellae and treated with collagenase and trypsin digestions, respectively. The apparent stiffness of the cartilage was measured by the OCT-based air-jet indentation system before and after the degeneration. The results were also compared with those from a rigid contact mechanical indentation and an ultrasound water-jet indentation. Through the air-jet indentation, it was found that the articular cartilage stiffness dropped significantly by 84% (p < 0.001) and 63% (p < 0.001) on average after collagenase and trypsin digestions, respectively. The stiffness measured by the air-jet indentation system was highly correlated (R > 0.8, p < 0.001) with that from the other two indentation methods. This study demonstrated that the OCT-based air-jet indentation can be a useful tool to quantitatively assess the mechanical properties of articular cartilage, and this encourages us to further develop a miniaturized probe suitable for arthroscopic applications.

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“…Their treatment of quantitative reconstruction [6] accounts for large deformation, but assumes a linear (neoHookean) stress-strain law. Nitta and Shiina [9], on the other hand, present “nonlinear elasticity” images that show tissue nonlinear stiffening. These represent the slope of the Young’s modulus with strain, based on two assumptions not made in Skovoroda’s work: stress is uniaxial and constant, and the stress-strain law is quadratic.…”

Section: Introductionmentioning

confidence: 99%

Recent Results in Nonlinear Strain and Modulus Imaging

Hall

Barbone²,

Oberai³

et al. 2011

CMIR

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We report a summary of recent developments and current status of our team’s efforts to image and quantify in vivo nonlinear strain and tissue mechanical properties. Our work is guided by a focus on applications to cancer diagnosis and treatment using clinical ultrasound imaging and quasi-static tissue deformations. We review our recent developments in displacement estimation from ultrasound image sequences. We discuss cross correlation approaches, regularized optimization approaches, guided search methods, multiscale methods, and hybrid methods. Current implementations can return results of high accuracy in both axial and lateral directions at several frames per second. We compare several strain estimators. Again we see a benefit from a regularized optimization approach. We then discuss both direct and iterative methods to reconstruct tissue mechanical property distributions from measured strain and displacement fields. We review the formulation, discretization, and algorithmic considerations that come into play when attempting to infer linear and nonlinear elastic properties from strain and displacement measurements. Finally we illustrate our progress with example applications in breast disease diagnosis and tumor ablation monitoring. Our current status shows that we have demonstrated quantitative determination of nonlinear parameters in phantoms and in vivo, in the context of 2D models and data. We look forward to incorporating 3D data from 2D transducer arrays to noninvasively create calibrated 3D quantitative maps of nonlinear elastic properties of breast tissues in vivo.

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A visualization of nonlinear elasticity property of tissues by ultrasound

Cited by 12 publications

References 6 publications

An optical coherence tomography (OCT)-based air jet indentation system for measuring the mechanical properties of soft tissues

An optical coherence tomography (OCT)-based air jet indentation system for measuring the mechanical properties of soft tissues

Quantification of Stiffness Change in Degenerated Articular Cartilage Using Optical Coherence Tomography-Based Air-Jet Indentation

Recent Results in Nonlinear Strain and Modulus Imaging

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