scholarly journals Two-dimensional shear wave speed and crawling wave speed recoveries from in vitro prostate data

2011 ◽  
Vol 130 (1) ◽  
pp. 585-598 ◽  
Author(s):  
Kui Lin ◽  
Joyce R. McLaughlin ◽  
Ashley Thomas ◽  
Kevin Parker ◽  
Benjamin Castaneda ◽  
...  
Keyword(s):  
Shear Wave ◽  
Wave Speed ◽  
Two Dimensional ◽  
Shear Wave Speed

scholarly journals A Cross-Machine Comparison of Shear-Wave Speed Measurements Using 2D Shear-Wave Elastography in the Normal Female Breast

2021 ◽  
Vol 11 (20) ◽  
pp. 9391
Author(s):  
Emma Harris ◽  
Ruchi Sinnatamby ◽  
Elizabeth O’Flynn ◽  
Anna M. Kirby ◽  
Jeffrey C. Bamber
Keyword(s):  
Adipose Tissue ◽  
Shear Wave ◽  
Subcutaneous Adipose Tissue ◽  
Wave Speed ◽  
Shear Wave Elastography ◽  
Shear Wave Speed ◽  
Skin Region ◽  
Subcutaneous Adipose

Quantitative measures of radiation-induced breast stiffness are required to support clinical studies of novel breast radiotherapy regimens and exploration of personalised therapy, however, variation between shear-wave elastography (SWE) machines may limit the usefulness of shear-wave speed (cs) for this purpose. Mean cs measured in four healthy volunteers’ breasts and a phantom using 2D-SWE machines Acuson S2000 (Siemens Medical Solutions) and Aixplorer (Supersonic Imagine) were compared. Shear-wave speed was measured in the skin region, subcutaneous adipose tissue and parenchyma. cs estimates were on average 2.3% greater when using the Aixplorer compared to S2000 in vitro. In vivo, cs estimates were on average 43.7%, 36.3% and 49.9% significantly greater (p << 0.01) when using the Aixplorer compared to S2000, for skin region, subcutaneous adipose tissue and parenchyma, respectively. In conclusion, despite relatively small differences between machines observed in vitro, large differences in absolute measures of shear wave speed measured were observed in vivo, which may prevent pooling of cross-machine data in clinical studies of the breast.

scholarly journals Feasibility and Reliability of Two-Dimensional Shear-Wave Elastography of the Liver of Clinically Healthy Cats

2020 ◽  
Vol 7 ◽  
Author(s):  
Kyeonga Kim ◽  
Jieun Lee ◽  
Jaebeom So ◽  
Yong-seok Jang ◽  
Mingyu Jung ◽  
...  
Keyword(s):  
Shear Wave ◽  
Wave Speed ◽  
Liver Stiffness ◽  
Shear Wave Elastography ◽  
Acoustic Radiation Force Impulse ◽  
Breath Holding ◽  
Two Dimensional ◽  
Shear Wave Speed ◽  
Left Liver ◽  
The Right

Given the broad overlap of normal and abnormal liver tissue in the subjective evaluation of the liver in conventional B-mode ultrasonography, there is a need for a non-invasive and quantitative method for the diagnosis of liver disease. Novel two-dimensional shear-wave elastography (2-D SWE) can measure tissue stiffness by propagation of the shear wave induced using acoustic radiation force impulse in real time. To the best of our knowledge, two-dimensional shear-wave measurement of the liver in cats has not been reported to date. This study assessed the feasibility, reliability, normal values, and related influencing factors of 2-D SWE for assessment of the feline liver without anesthesia and breath-holding. Two-dimensional shear-wave ultrasonography was performed by two evaluators at the right and left sides of the liver. Twenty-nine client-owned clinically healthy adult cats were included. The means and standard deviations for the shear-wave speed and stiffness in the right liver were 1.52 ± 0.13 m/s and 6.94 ± 1.26 kPa, respectively, and those for the left liver were 1.61 ± 0.15 m/s and 7.90 ± 1.47 kPa, respectively. Shear-wave speed (P = 0.005) and stiffness (P = 0.002) were significantly lower in the right liver when compared to the left. The intraclass correlation value for liver stiffness was 0.835 and 0.901 for the right and left liver, respectively, indicating high interobserver agreement. Age, weight, body condition score (BCS), gabapentin administration, and measurement depths were not significantly correlated with liver stiffness or elastography measurements (P &gt; 0.05). Our findings suggest that 2-D SWE measurements of the liver are not influenced significantly by age, weight, or BCS and can be reliably performed without anesthesia and breath-holding in cats. The values determined here can help form the basis for reference elastography values for evaluation of the feline liver.

Fast shear compounding using directional filtering and two-dimensional shear wave speed calculation

2013 ◽  
Author(s):  
Pengfei Song ◽  
Armando Manduca ◽  
Heng Zhao ◽  
Matthew W. Urban ◽  
James F. Greenleaf ◽  
...  
Keyword(s):  
Shear Wave ◽  
Wave Speed ◽  
Two Dimensional ◽  
Shear Wave Speed ◽  
Directional Filtering

scholarly journals Spatial variations in Achilles tendon shear wave speed

2014 ◽  
Vol 47 (11) ◽  
pp. 2685-2692 ◽  
Author(s):  
Ryan J. DeWall ◽  
Laura C. Slane ◽  
Kenneth S. Lee ◽  
Darryl G. Thelen
Keyword(s):  
Achilles Tendon ◽  
Shear Wave ◽  
Wave Speed ◽  
Spatial Variations ◽  
Shear Wave Speed

Measured temperature and pressure dependence of Vp and Vs in compacted, polycrystalline sI methane and sII methane–ethane hydrate

2003 ◽  
Vol 81 (1-2) ◽  
pp. 47-53 ◽  
Author(s):  
M B Helgerud ◽  
W F Waite ◽  
S H Kirby ◽  
A Nur
Keyword(s):  
High Pressure ◽  
Shear Wave ◽  
Pressure Dependence ◽  
Gas Hydrate ◽  
Pressure Vessel ◽  
Wave Speed ◽  
Measured Temperature ◽  
Shear Wave Speed ◽  
Temperature And Pressure ◽  
Fixed End

We report on compressional- and shear-wave-speed measurements made on compacted polycrystalline sI methane and sII methane–ethane hydrate. The gas hydrate samples are synthesized directly in the measurement apparatus by warming granulated ice to 17°C in the presence of a clathrate-forming gas at high pressure (methane for sI, 90.2% methane, 9.8% ethane for sII). Porosity is eliminated after hydrate synthesis by compacting the sample in the synthesis pressure vessel between a hydraulic ram and a fixed end-plug, both containing shear-wave transducers. Wave-speed measurements are made between –20 and 15°C and 0 to 105 MPa applied piston pressure. PACS No.: 61.60Lj

Diagnosis of liver fibrosis based on quantification of factors associated with shear wave speed

Choonpa Igaku ◽  
2021 ◽  
Author(s):  
Hiroko IIJIMA ◽  
Toshifumi TADA ◽  
Hiroyuki HACHIYA ◽  
Takashi NISHIMURA ◽  
Junko NISHIMURA ◽  
...  
Keyword(s):  
Liver Fibrosis ◽  
Shear Wave ◽  
Wave Speed ◽  
Shear Wave Speed ◽  
Factors Associated

scholarly journals A soft cervix, categorized by shear-wave elastography, in women with short or with normal cervical length at 18–24 weeks is associated with a higher prevalence of spontaneous preterm delivery

2018 ◽  
Vol 46 (5) ◽  
pp. 489-501 ◽  
Author(s):  
Edgar Hernandez-Andrade ◽  
Eli Maymon ◽  
Suchaya Luewan ◽  
Gaurav Bhatti ◽  
Mohammad Mehrmohammadi ◽  
...  
Keyword(s):  
Cohort Study ◽  
Preterm Delivery ◽  
Shear Wave ◽  
Wave Speed ◽  
Shear Wave Elastography ◽  
Cervical Length ◽  
Singleton Pregnancy ◽  
Short Cervix ◽  
Shear Wave Speed ◽  
Spontaneous Preterm Delivery

AbstractObjective:To determine whether a soft cervix identified by shear-wave elastography between 18 and 24 weeks of gestation is associated with increased frequency of spontaneous preterm delivery (sPTD).Materials and methods:This prospective cohort study included 628 consecutive women with a singleton pregnancy. Cervical length (mm) and softness [shear-wave speed: (SWS) meters per second (m/s)] of the internal cervical os were measured at 18–24 weeks of gestation. Frequency of sPTD <37 (sPTD<37) and <34 (sPTD<34) weeks of gestation was compared among women with and without a short (≤25 mm) and/or a soft cervix (SWS <25thpercentile).Results:There were 31/628 (4.9%) sPTD<37 and 12/628 (1.9%) sPTD<34 deliveries. The combination of a soft and a short cervix increased the risk of sPTD<37 by 18-fold [relative risk (RR) 18.0 (95% confidence interval [CI], 7.7–43.9); P<0.0001] and the risk of sPTD<34 by 120-fold [RR 120.0 (95% CI 12.3–1009.9); P<0.0001] compared to women with normal cervical length. A soft-only cervix increased the risk of sPTD<37 by 4.5-fold [RR 4.5 (95% CI 2.1–9.8); P=0.0002] and of sPTD<34 by 21-fold [RR 21.0 (95% CI 2.6–169.3); P=0.0003] compared to a non-soft cervix.Conclusions:A soft cervix at 18–24 weeks of gestation increases the risk of sPTD <37 and <34 weeks of gestation independently of cervical length.

Sensitivity of the Shear Wave Speed-Stress Relationship to Soft Tissue Material Properties and Fiber Alignment

2021 ◽  
Author(s):  
Jonathon Blank ◽  
Darryl Thelen ◽  
Matthew S. Allen ◽  
Joshua Roth
Keyword(s):  
Wave Propagation ◽  
Shear Modulus ◽  
Shear Wave ◽  
Wave Speed ◽  
Axial Stress ◽  
Beam Model ◽  
Fiber Alignment ◽  
Wave Speeds ◽  
Shear Wave Speed ◽  
Constitutive Properties

The use of shear wave propagation to noninvasively gauge material properties and loading in tendons and ligaments is a growing area of interest in biomechanics. Prior models and experiments suggest that shear wave speed primarily depends on the apparent shear modulus (i.e., shear modulus accounting for contributions from all constituents) at low loads, and then increases with axial stress when axially loaded. However, differences in the magnitudes of shear wave speeds between ligaments and tendons, which have different substructures, suggest that the tissue’s composition and fiber alignment may also affect shear wave propagation. Accordingly, the objectives of this study were to (1) characterize changes in the apparent shear modulus induced by variations in constitutive properties and fiber alignment, and (2) determine the sensitivity of the shear wave speed-stress relationship to variations in constitutive properties and fiber alignment. To enable systematic variations of both constitutive properties and fiber alignment, we developed a finite element model that represented an isotropic ground matrix with an embedded fiber distribution. Using this model, we performed dynamic simulations of shear wave propagation at axial strains from 0% to 10%. We characterized the shear wave speed-stress relationship using a simple linear regression between shear wave speed squared and axial stress, which is based on an analytical relationship derived from a tensioned beam model. We found that predicted shear wave speeds were both in-range with shear wave speeds in previous in vivo and ex vivo studies, and strongly correlated with the axial stress (R2 = 0.99). The slope of the squared shear wave speed-axial stress relationship was highly sensitive to changes in tissue density. Both the intercept of this relationship and the apparent shear modulus were sensitive to both the shear modulus of the ground matrix and the stiffness of the fibers’ toe-region when the fibers were less well-aligned to the loading direction. We also determined that the tensioned beam model overpredicted the axial tissue stress with increasing load when the model had less well-aligned fibers. This indicates that the shear wave speed increases likely in response to a load-dependent increase in the apparent shear modulus. Our findings suggest that researchers may need to consider both the material and structural properties (i.e., fiber alignment) of tendon and ligament when measuring shear wave speeds in pathological tissues or tissues with less well-aligned fibers.

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