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Ceska a Slovenska Oftalmologie :... 2016Shear wave elastography (SWE) is a new non-invasive diagnostic imaging technique, that maps the elastic properties of tissues. Nowadays this modality develops... (Review)
Review
Shear wave elastography (SWE) is a new non-invasive diagnostic imaging technique, that maps the elastic properties of tissues. Nowadays this modality develops increasingly in medicine across its disciplines and opens a new era of high-quality ultrasound examination because it increases the specificity and thus improves diagnostic assurance. This method is similar to manual palpation, shows elastic properties of biological tissues and provides a kind of reconstruction of the internal structure of soft tissues based on measurement of the response of tissue compression. Various biological tissues have different elasticity and changes of these elastic properties often reflect pathological processes in the tissue and its abnormalities. This method is already used routinely on some foreign institutions in the detection and diagnosis of breast cancer and thyroid cancer, prostate cancer, in hepatology, cardiology, view the carotid arteries and lymphatic nodules. Finally examines its unquestioned benefit in ophthalmology. The output of elastography is an ultrasound image B-mode superimposed color-coded map. Shear waves elastography provides three major innovations: the quantitative aspect, the spatial resolution and the ability to run in real time.Key words: ultrasound, elastography, Youngs modulus, shear-wave, SonicTouchTM, UltrafastTM display.
Topics: Diagnostic Techniques, Ophthalmological; Elastic Modulus; Elasticity Imaging Techniques; Humans; Ultrasonography
PubMed: 27860475
DOI: No ID Found -
Scientific Reports Aug 2020To comprehend the most detrimental characteristics behind bone fractures, it is key to understand the material and tissue level strain limits and their relation to...
To comprehend the most detrimental characteristics behind bone fractures, it is key to understand the material and tissue level strain limits and their relation to failure sites. The aim of this study was to investigate the three-dimensional strain distribution and its evolution during loading at the sub-trabecular level in trabecular bone tissue. Human cadaver trabecular bone samples were compressed in situ until failure, while imaging with high-resolution synchrotron radiation X-ray tomography. Digital volume correlation was used to determine the strains inside the trabeculae. Regions without emerging damage were compared to those about to crack. Local strains in close vicinity of developing cracks were higher than previously reported for a whole trabecular structure and similar to those reported for single isolated trabeculae. Early literature on bone fracture strain thresholds at the tissue level seem to underestimate the maximum strain magnitudes in trabecular bone. Furthermore, we found lower strain levels and a reduced ability to capture detailed crack-paths with increased image voxel size. This highlights the dependence between the observed strain levels and the voxel size and that high-resolution is needed to investigate behavior of individual trabeculae. Furthermore, low trabecular thickness appears to be one predictor of developing cracks. In summary, this study investigated the local strains in whole trabecular structure at sub-trabecular resolution in human bone and confirmed the high strain magnitudes reported for single trabeculae under loading and, importantly extends its translation to the whole trabecular structure.
Topics: Bone and Bones; Cancellous Bone; Elasticity; Fractures, Stress; Humans; Spine; Stress, Mechanical; Synchrotrons; Tomography, X-Ray Computed; Weight-Bearing
PubMed: 32796859
DOI: 10.1038/s41598-020-69850-x -
Journal of Applied Physiology... May 2019Skeletal muscles' primary function in the body is mechanical: to move and stabilize the skeleton. As such, their mechanical behavior is a key aspect of their physiology.... (Review)
Review
Skeletal muscles' primary function in the body is mechanical: to move and stabilize the skeleton. As such, their mechanical behavior is a key aspect of their physiology. Recent developments in medical imaging technology have enabled quantitative studies of passive muscle mechanics, ranging from measurements of intrinsic muscle mechanical properties, such as elasticity and viscosity, to three-dimensional muscle architecture and dynamic muscle deformation and kinematics. In this review we summarize the principles and applications of contemporary imaging methods that have been used to study the passive mechanical behavior of skeletal muscles. Elastography measurements can provide in vivo maps of passive muscle mechanical parameters, and both MRI and ultrasound methods are available (magnetic resonance elastography and ultrasound shear wave elastography, respectively). Both have been shown to differentiate between healthy muscle and muscles affected by a broad range of clinical conditions. Detailed muscle architecture can now be depicted using diffusion tensor imaging, which not only is particularly useful for computational modeling of muscle but also has potential in assessing architectural changes in muscle disorders. More dynamic information about muscle mechanics can be obtained using a range of dynamic MRI methods, which characterize the detailed internal muscle deformations during motion. There are several MRI techniques available (e.g., phase-contrast MRI, displacement-encoded MRI, and "tagged" MRI), each of which can be collected in synchrony with muscle motion and postprocessed to quantify muscle deformation. Together, these modern imaging techniques can characterize muscle motion, deformation, mechanical properties, and architecture, providing complementary insights into skeletal muscle function.
Topics: Animals; Biomechanical Phenomena; Elasticity; Humans; Magnetic Resonance Imaging; Muscle, Skeletal; Stress, Mechanical; Viscosity
PubMed: 30236053
DOI: 10.1152/japplphysiol.00672.2018 -
International Journal of Molecular... Feb 2022Many extensible tissues such as skin, lungs, and blood vessels require elasticity to function properly. The recoil of elastic energy stored during a stretching phase is... (Review)
Review
Many extensible tissues such as skin, lungs, and blood vessels require elasticity to function properly. The recoil of elastic energy stored during a stretching phase is provided by elastic fibers, which are mostly composed of elastin and fibrillin-rich microfibrils. In arteries, the lack of elastic fibers leads to a weakening of the vessel wall with an increased risk to develop cardiovascular defects such as stenosis, aneurysms, and dissections. The development of new therapeutic molecules involves preliminary tests in animal models that recapitulate the disease and whose response to drugs should be as close as possible to that of humans. Due to its superior in vivo imaging possibilities and the broad tool kit for forward and reverse genetics, the zebrafish has become an important model organism to study human pathologies. Moreover, it is particularly adapted to large scale studies, making it an attractive model in particular for the first steps of investigations. In this review, we discuss the relevance of the zebrafish model for the study of elastic fiber-related vascular pathologies. We evidence zebrafish as a compelling alternative to conventional mouse models.
Topics: Animals; Blood Vessels; Elastic Tissue; Elasticity; Fibrillins; Humans; Microfilament Proteins; Zebrafish
PubMed: 35216218
DOI: 10.3390/ijms23042102 -
Journal of the Mechanical Behavior of... Feb 2022Developing a shear wave tensiometer capable of non-invasively measuring ligament tension holds promise for enhancing research and clinical assessments of ligament...
Developing a shear wave tensiometer capable of non-invasively measuring ligament tension holds promise for enhancing research and clinical assessments of ligament function. Such development would benefit from tunable test specimens fabricated from well-characterized and consistent materials. Although previous work found that yarn can replicate the mechanical behavior of collateral ligaments, it is not obvious whether yarn-based phantoms would be suitable for development of a shear wave tensiometer for measuring ligament tension. Accordingly, the primary objective of this study was to characterize the mechanical properties and shear wave speed - stress relationships of ligament phantoms fabricated from yarn and silicone, and compare these results to published data from biological ligaments. We measured the mechanical properties and shear wave speeds during axial loading in nine phantoms with systematically varied material properties. We performed a simple linear regression between shear wave speed squared and axial stress to determine the shear wave speed - stress relationship for each phantom. We found comparable elastic moduli, hysteresis, and shear wave speed squared - stress regression parameters between the phantoms and collateral ligaments. For example, the ranges of the coefficients of determination (R) and slopes across the nine phantoms were 0.84-0.95, and 0.78-1.27 kPa/m/s, respectively, which overlapped with the ranges found in a prior study in porcine collateral ligaments (0.84-0.996 and 0.34-1.18 kPa/m/s, respectively). Additionally, the shear wave speed squared - stress regression parameters varied predictably with the density of the phantom and the shear modulus of the silicone. In summary, we found that yarn-based phantoms serve as mechanical analogs for ligaments (i.e., are ligament mimicking), and thus, should prove beneficial for investigations into ligament structure-function relationships and in the development of a shear wave tensiometer for measuring ligament tension.
Topics: Animals; Elastic Modulus; Elasticity Imaging Techniques; Ligaments; Phantoms, Imaging; Stress, Mechanical; Swine; Weight-Bearing
PubMed: 34857491
DOI: 10.1016/j.jmbbm.2021.104984 -
International Journal of Molecular... Mar 2021A flexible and bioactive scaffold for adipose tissue engineering was fabricated and evaluated by dual nozzle three-dimensional printing. A highly elastic poly...
A flexible and bioactive scaffold for adipose tissue engineering was fabricated and evaluated by dual nozzle three-dimensional printing. A highly elastic poly (L-lactide-co-ε-caprolactone) (PLCL) copolymer, which acted as the main scaffolding, and human adipose tissue derived decellularized extracellular matrix (dECM) hydrogels were used as the printing inks to form the scaffolds. To prepare the three-dimensional (3D) scaffolds, the PLCL co-polymer was printed with a hot melting extruder system while retaining its physical character, similar to adipose tissue, which is beneficial for regeneration. Moreover, to promote adipogenic differentiation and angiogenesis, adipose tissue-derived dECM was used. To optimize the printability of the hydrogel inks, a mixture of collagen type I and dECM hydrogels was used. Furthermore, we examined the adipose tissue formation and angiogenesis of the PLCL/dECM complex scaffold. From in vivo experiments, it was observed that the matured adipose-like tissue structures were abundant, and the number of matured capillaries was remarkably higher in the hydrogel-PLCL group than in the PLCL-only group. Moreover, a higher expression of M2 macrophages, which are known to be involved in the remodeling and regeneration of tissues, was detected in the hydrogel-PLCL group by immunofluorescence analysis. Based on these results, we suggest that our PLCL/dECM fabricated by a dual 3D printing system will be useful for the treatment of large volume fat tissue regeneration.
Topics: Adipose Tissue; Animals; Cell Adhesion; Cell Differentiation; Elasticity; Extracellular Matrix; Humans; Hydrogels; Polymers; Printing, Three-Dimensional; Regeneration; Tissue Engineering; Tissue Scaffolds; Wound Healing
PubMed: 33809175
DOI: 10.3390/ijms22062886 -
Optics Letters Oct 2021In this work, we present an ultra-fast line-field optical coherence elastography system (LF-OCE) with an 11.5 MHz equivalent A-line rate. The system was composed of a...
In this work, we present an ultra-fast line-field optical coherence elastography system (LF-OCE) with an 11.5 MHz equivalent A-line rate. The system was composed of a line-field spectral domain optical coherence tomography system based on a supercontinuum light source, Michelson-type interferometer, and a high-speed 2D spectrometer. The system performed ultra-fast imaging of elastic waves in tissue-mimicking phantoms of various elasticities. The results corroborated well with mechanical testing. Following validation, LF-OCE measurements were made in in situ and in in vivo rabbit corneas under various conditions. The results show the capability of the system to rapidly image elastic waves in tissues.
Topics: Animals; Cornea; Elasticity; Elasticity Imaging Techniques; Phantoms, Imaging; Rabbits; Tomography, Optical Coherence
PubMed: 34598188
DOI: 10.1364/OL.435278 -
Journal of Athletic Training Apr 2023Myotonometry is a relatively novel method used to quantify the biomechanical and viscoelastic properties (stiffness, compliance, tone, elasticity, creep, and mechanical... (Review)
Review
Myotonometry is a relatively novel method used to quantify the biomechanical and viscoelastic properties (stiffness, compliance, tone, elasticity, creep, and mechanical relaxation) of palpable musculotendinous structures with portable mechanical devices called myotonometers. Myotonometers obtain these measures by recording the magnitude of radial tissue deformation that occurs in response to the amount of force that is perpendicularly applied to the tissue through a device's probe. Myotonometric parameters such as stiffness and compliance have repeatedly demonstrated strong correlations with force production and muscle activation. Paradoxically, individual muscle stiffness measures have been associated with both superior athletic performance and a higher incidence of injury. This indicates optimal stiffness levels may promote athletic performance, whereas too much or too little may lead to an increased risk of injury. Authors of numerous studies suggested that myotonometry may assist practitioners in the development of performance and rehabilitation programs that improve athletic performance, mitigate injury risk, guide therapeutic interventions, and optimize return-to-activity decision-making. Thus, the purpose of our narrative review was to summarize the potential utility of myotonometry as a clinical tool that assists musculoskeletal clinicians with the diagnosis, rehabilitation, and prevention of athletic injuries.
Topics: Humans; Muscle, Skeletal; Elasticity; Mechanical Phenomena; Athletic Injuries
PubMed: 37418563
DOI: 10.4085/616.21 -
IEEE Transactions on Ultrasonics,... Jun 2020Viscoelastic response (VisR) ultrasound characterizes the viscoelastic properties of tissue by fitting acoustic radiation force (ARF)-induced displacements in the region...
Viscoelastic response (VisR) ultrasound characterizes the viscoelastic properties of tissue by fitting acoustic radiation force (ARF)-induced displacements in the region of ARF excitation to a 1-D mass-spring-damper (MSD) model. Elasticity and viscosity are calculated separately but relative to the applied ARF amplitude. We refer to these parameters as "relative elasticity (RE)" and "relative viscosity (RV)." We herein test the hypothesis that RE and RV linearly correlate to true elasticity and viscosity in tissue. VisR imaging was simulated in 144 homogeneous viscoelastic materials with varying elasticities and viscosities. Derived RE linearly correlated with material elasticity and varied by an average of 2.52% when the material viscosity changed from 0.1 to 1.3 Pa · s. Derived RV linearly correlated with material viscosity but varied by an average of 102.5% when material elasticity changed from 3.33 to 20 kPa. The effect of elasticity on RV measurement was compensated using the slope of the linear relationship between RV and natural frequency ( ω ). After compensation, RV [Formula: see text] (elasticity compensated RV) linearly correlated with material viscosity and varied by less than 1.00% on average when the modeled shear elastic modulus changed from 3.3 to 20 kPa. In addition to elasticity compensation, variation in ARF amplitude over depth was compensated, yielding RE and [Formula: see text]. RE and [Formula: see text] successfully contrasted elastic and viscous inclusions, respectively, in three simulated phantoms. Experimentally, in the homogeneous oil-in-gelatin phantoms and excised livers, RE linearly correlated with shear wave dispersion ultrasound vibrometry (SDUV) derived shear elastic modulus, and [Formula: see text] linearly correlated with SDUV-derived shear viscosity. In excised livers containing viscoelastic oil-in-gelatin inclusions, the inclusions were successfully contrasted from the liver background by both RE and [Formula: see text]. These results suggest that RE and RV are relevant for qualitatively assessing the elastic and viscous properties of tissue.
Topics: Animals; Computer Simulation; Dogs; Elasticity; Elasticity Imaging Techniques; Image Processing, Computer-Assisted; Liver; Phantoms, Imaging; Viscosity
PubMed: 31899421
DOI: 10.1109/TUFFC.2019.2962789 -
Journal of the Mechanical Behavior of... Jan 2022Despite the extensive studies on biological function of osteocytes, there are limited studies that evaluated the structural role of osteocyte lacunae on local mechanical...
Despite the extensive studies on biological function of osteocytes, there are limited studies that evaluated the structural role of osteocyte lacunae on local mechanical properties of the bone matrix. As a result, the goal of this study was to elucidate the independent contribution of osteocyte lacunae structure on mechanical properties and fracture behavior of the bone matrix uncoupled from its biological effects and bone tissue composition variation. This study combined cohesive finite element modeling with experimental data from a lactation rat model to evaluate the influence of osteocyte lacunar area porosity, density, size, axis ratio, and orientation on the elastic modulus, ultimate strength, and ultimate strain of the bone matrix as well as on local crack formation and propagation. It also performed a parametric study to isolate the influence of a single osteocyte lacunae structural property on the mechanical properties of the bone matrix. The experimental measurements demonstrated statistically significant differences in lacunar size between ovariectomized rats with lactation history and virgin groups (both ovariectomized and intact) and in axis ratio between rats with lactation history and virgins. There were no differences in mechanical properties between virgin and lactation groups as determined by the finite element simulations. However, there were statistically significant linear relationships between the physiological range of osteocyte lacunar area porosity, density, size, and orientation and the elastic modulus and ultimate strength of the bone matrix in virgin and lactation rats. The parametric study also revealed similar but stronger relationships between elastic modulus and ultimate strength and lacunar density, size, and orientation. The simulations also demonstrated that the osteocyte lacunae guided the crack propagation through local stress concentrations. In summary, this study enhanced the limited knowledge on the structural role of osteocyte lacunae on local mechanical properties of the bone matrix. These data are important in gaining a better understanding of the mechanical implications of the local modifications due to osteocytes in the bone matrix.
Topics: Animals; Bone Matrix; Elastic Modulus; Female; Finite Element Analysis; Osteocytes; Porosity; Rats
PubMed: 34736032
DOI: 10.1016/j.jmbbm.2021.104943