scholarly journals Experimental Evidence of Generation and Reception by a Transluminal Axisymmetric Shear Wave Elastography Prototype

Diagnostics ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 645
Author(s):  
Antonio Gomez ◽  
Manuel Hurtado ◽  
Antonio Callejas ◽  
Jorge Torres ◽  
Nader Saffari ◽  
...  
Keyword(s):  
Experimental Evidence ◽  
Shear Wave ◽  
Shear Wave Elastography ◽  
Sensing Element ◽  
New Approach ◽  
Shear Wave Speed ◽  
Ultrafast Imaging ◽  
Axisymmetric Shear ◽  
Rotational Actuator ◽  
Good Agreement

Experimental evidence on testing a non-ultrasonic-based probe for a new approach in transluminal elastography was presented. The proposed modality generated shear waves by inducing oscillatory rotation on the lumen wall. Detection of the propagated waves was achieved at a set of receivers in mechanical contact with the lumen wall. The excitation element of the probe was an electromagnetic rotational actuator whilst the sensing element was comprised by a uniform anglewise arrangement of four piezoelectric receivers. The prototype was tested in two soft-tissue-mimicking phantoms that contained lumenlike conduits and stiffer inclusions. The shear wave speed of the different components of the phantoms was characterized using shear wave elastography. These values were used to estimate the time-of-flight of the expected reflections. Ultrafast ultrasound imaging, based on Loupas’ algorithm, was used to estimate the displacement field in transversal planes to the lumenlike conduit and to compare against the readouts from the transluminal transmission–reception tests. Experimental observations between ultrafast imaging and the transluminal probe were in good agreement, and reflections due to the stiffer inclusions were detected by the transluminal probe. The obtained experimental evidence provided proof-of-concept for the transluminal elastography probe and encouraged further exploration of clinical applications.

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.

scholarly journals Strain Elastography - How To Do It?

2017 ◽  
Vol 03 (04) ◽  
pp. E137-E149 ◽  
Author(s):  
Christoph Dietrich ◽  
Richard Barr ◽  
André Farrokh ◽  
Manjiri Dighe ◽  
Michael Hocke ◽  
...  
Keyword(s):  
Shear Wave ◽  
Wave Speed ◽  
Shear Wave Elastography ◽  
Ultrasound Elastography ◽  
Tissue Stiffness ◽  
Shear Wave Speed ◽  
Strain Elastography ◽  
Advantages And Disadvantages ◽  
Similar Information ◽  
Qualitative Technique

AbstractTissue stiffness assessed by palpation for diagnosing pathology has been used for thousands of years. Ultrasound elastography has been developed more recently to display similar information on tissue stiffness as an image. There are two main types of ultrasound elastography, strain and shear wave. Strain elastography is a qualitative technique and provides information on the relative stiffness between one tissue and another. Shear wave elastography is a quantitative method and provides an estimated value of the tissue stiffness that can be expressed in either the shear wave speed through the tissues in meters/second, or converted to the Young’s modulus making some assumptions and expressed in kPa. Each technique has its advantages and disadvantages and they are often complimentary to each other in clinical practice. This article reviews the principles, technique, and interpretation of strain elastography in various organs. It describes how to optimize technique, while pitfalls and artifacts are also discussed.

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.

Abstract 139: Future Clinical Tools: Carotid Plaque Characterization via Shear Wave Elastography - A Phantom Study

Stroke ◽  
2015 ◽  
Vol 46 (suppl_1) ◽  
Author(s):  
Erik Widman ◽  
Elira Maksuti ◽  
Matthew Urban ◽  
Kenneth Caidahl ◽  
Matilda Larsson
Keyword(s):  
Shear Modulus ◽  
Mechanical Testing ◽  
Shear Wave ◽  
High Speed ◽  
Acoustic Radiation ◽  
Shear Wave Elastography ◽  
Radiation Force ◽  
Acoustic Radiation Force ◽  
Good Agreement

Introduction: Shear Wave Elastography (SWE) is a recently developed noninvasive method for elastography assessment using ultrasound. The technique consists of sending an acoustic radiation force into the tissue that in turn generates an orthogonal low frequency propagating shear wave. The shear wave propagation speed, which is calculated from B-mode images, is correlated to the tissues mechanical properties. Currently, SWE is primarily used in breast and liver to detect tumors easily missed with normal B-mode ultrasound. SWE could potentially aid in the characterization of plaques in the carotid artery, which is critical for the prevention of ischemic stroke. Methods: Six polyvinyl alcohol (PVA) phantoms were created with soft and hard plaque mimicking inclusions. The plaques were excited with acoustic radiation force and the shear wave was measured using high speed B-mode imaging. The data was post-processed with a custom in-house algorithm fitting a model of a Lamb wave propagating through a plate to the shear wave dispersion curve, which allowed the shear modulus to be estimated. The results were validated by measuring the phantom plaque shear modulus with mechanical testing. Results: SWE measured a mean shear modulus of 6 ± 1 kPa and 106 ± 17 kPa versus 3 kPa and 95 kPa measured by mechanical testing in the soft and hard plaques respectively. The results show good agreement between the shear modulus measured with SWE and mechanical testing. In this study simplified homogenous phantom plaque models were examined in a static experimental setup with results validated by mechanical testing. Algorithm improvements for measurements in a dynamic environment are being developed for a future in vivo pilot study. Conclusion: The results show good agreement between the shear modulus measured with SWE and mechanical testing and indicate the possibility for an in vivo application.

Modern sonographic markers for the prognosis of preterm birth in women with different somatotypes

2021 ◽  
Vol 70 (4) ◽  
pp. 91-98
Author(s):  
Kristina G. Tomaeva ◽  
Sergey N. Gaidukov ◽  
Elena N. Komissarova ◽  
Georgii G, Tomaev
Keyword(s):  
Preterm Birth ◽  
Pregnant Women ◽  
Shear Wave ◽  
Wave Speed ◽  
Shear Wave Elastography ◽  
Test Method ◽  
Shear Wave Speed ◽  
Risk Of Death ◽  
Increased Risk ◽  
Average Shear

BACKGROUND:Preterm birth is one of the causes of perinatal morbidity and mortality. Premature infants have an increased risk of death and the development of neurological and other disorders. AIM:The aim of this study was to evaluate the modern sonographic parameters of the cervix in pregnant women with different somatotypes and to develop a mathematical model for predicting preterm birth. MATERIALS AND METHODS:The study included 390 women, among whom 110 were classified with macrosomatic, 173 with mesosomatic, and 107 with microsomatic types. Somatotype was determined in women in early stages of pregnancy (before 9-10 weeks of gestation) using the R.N. Dorokhov anthropometric test method. The utero-cervical angle was measured, shear wave elastography was performed, and the average shear wave speed in the area of the internal cervical os was determined. All measurements were performed on a Philips EPIQ 5 ultrasound machine. RESULTS:Preterm birth was more often identified in women with macro- and microsomatic types in comparison with women with mesosomatic type (p 0.05). In pregnant women with subsequent preterm birth at 22-23 weeks, the average SWS in the area of the internal cervical os was reduced (p 0.05) and the utero-cervical angle was higher in comparison with those women who did not have preterm birth (p 0.05). Using multiple regression analysis, we obtained the regression equation (formula), which predicts the development of preterm birth in women with different somatotypes. CONCLUSIONS:Such parameters as the average shear wave speed in the area of the internal cervical os and the utero-cervical angle may be regarded as markers of preterm birth. The mathematical formula obtained allows for predicting the development of preterm birth in women with different somatotypes and for timely prevention of pathology.

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