scholarly journals Impact of Fibrotic Tissue on Shear Wave Velocity in Thyroid: AnEx VivoStudy with Fresh Thyroid Specimens

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Takahiro Fukuhara ◽  
Eriko Matsuda ◽  
Yukari Endo ◽  
Ryohei Donishi ◽  
Shoichiro Izawa ◽  
...  
Keyword(s):  
Lymph Node ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Metastatic Lymph Node ◽  
Pathological Examination ◽  
Metastatic Lymph ◽  
The Mean ◽  
Benign Thyroid ◽  
Severe Fibrosis

We sought to elucidate the correlation between shear wave velocity (SWV) and fibrosis in thyroid by precisely assessing pathological structures inside 5 × 5 mm2regions of interest (ROIs) of resected specimens, under conditions that excluded physical artifacts. The materials were unselected thyroid and lymph node specimens resected during thyroid surgery. Immediately after surgery, fresh unfixed thyroid and metastatic lymph node specimens were suspended in gel phantoms, and SWV was measured. Upon pathological examination of each specimen, the extent of fibrosis was graded as none, moderate, or severe. A total of 109 specimens were evaluated: 15 normal thyroid, 16 autoimmune thyroiditis, 40 malignant nodules, 19 benign thyroid nodules, and 19 metastatic lymph nodes. When all specimens were classified according to the degree of fibrosis determined by pathological imaging, the mean SWV was1.49±0.39 m/s for no fibrosis,2.13±0.66 m/s for moderate fibrosis, and2.68±0.82 m/s for severe fibrosis. The SWVs of samples with moderate and severe fibrosis were significantly higher than those of samples without fibrosis. The results of this study demonstrate that fibrosis plays an important role in determining stiffness, as measured by SWV in thyroid.

scholarly journals Area Covered for Shear Wave Velocity Calculation Affects the Shear Wave Velocity Values

2019 ◽  
Vol 35 (3) ◽  
pp. 182-187
Author(s):  
Amitabh Dashottar ◽  
Erin Montambault ◽  
Jeffrey R. Betz ◽  
Kevin D. Evans
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Region Of Interest ◽  
Ultrasound Elastography ◽  
Maximum Area ◽  
Shear Wave Velocities ◽  
Significant Difference ◽  
Technical Specifications ◽  
The Mean

Although ultrasound elastography is established as a reliable and valid tool for assessment of skeletal muscles, guidelines around the technical specifications, data selection, and acquisition parameters still lack consensus. One such parameter is the use of the quantification box (Q-box) that calculates the shear wave velocity/modulus, within a selected region of interest (ROI). Currently, no data compare the effect of the elastographic area within the ROI to the mean shear wave velocity calculations, using a Q-box. In this study, the mean shear wave velocity calculated over a smaller (single Q-box) ROI is compared to the mean shear wave velocity calculated over maximum area of elastogram, within a ROI. Comparison of mean shear wave velocity revealed a significant difference ( t = 2.79, P = .007) between the means calculated over maximum area of elastogram for only nonuniform elastograms. The rater agreement for the classification scheme was assessed (κ = 0.85). To prevent possible overestimation of shear wave velocities, it may be necessary to place the Q-box over the maximum elastographic area.

scholarly journals The influence of acute physical effort on liver stiffness estimation using Virtual Touch Quantification (VTQ). Preliminary results.

2016 ◽  
Vol 18 (2) ◽  
pp. 151 ◽  
Author(s):  
Mariana M Gersak ◽  
Erich Sorantin ◽  
Jana Windhaber ◽  
Sorin M Dudea ◽  
Michael Riccabona
Keyword(s):  
Blood Flow ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Liver Blood Flow ◽  
Liver Stiffness ◽  
Physical Effort ◽  
Wave Velocities ◽  
Shear Wave Velocities ◽  
The Mean

Aim: Food intake and acutely decompensated cardiac failure may impair liver stiffness estimations, mainly because these methods are influenced by liver blood flow variation encountered in these conditions. It is well known that also during physical effort liver blood flow changes, due to the redistribution of blood flow mainly to the skeletal muscles. The aim of this study is to assess the change of liver shear- wave velocities immediately after cessation of an acute physical effort. A secondary aim was to find the proper timing for accurate liver stiffness estimation after physical exhaustion. Material and methods: Liver shear-wave velocities were measured using virtual touch quantification (VTQ) in seven apparently healthy volunteers, in fasting conditions. All subjects underwent a complete abdominal ultrasound study, including the liver VTQ. Then, all subjects performed a spiroergometry and thereafter, another series of three liver shear-wave velocity measurements were performed: immediately after spiroergometry, five min, and ten min after spiroergometry, respectively. Results: Before spiroergoemetry, the mean liver shear-wave velocity was 1.05±0.12 m/sec. Immediately after spiroergometry, mean liver shear-wave velocities increased significantly, measuring 1.34±0.16 m/sec (p <0.01). The mean liver shear-wave velocities at five and ten minutes after exhausting were 1.23±0.14 m/sec and 1.05±0.11 m/sec respectively. Conclusions: Liver stiffness estimation using VTQ was influenced by acute physical exercise in our study group. Despite the small number of subjects, the preliminary results show that if patients had done physical effort before VTQ elastography, they should rest at least ten minutes before reliable liver stiffness estimations can be performed.

scholarly journals Reliability of testicular stiffness quantification using shear wave elastography in predicting male fertility: a preliminary prospective study

2018 ◽  
Vol 20 (2) ◽  
pp. 141 ◽  
Author(s):  
Alpaslan Yavuz ◽  
Adem Yokus ◽  
Kerem Taken ◽  
Abdussamet Batur ◽  
Mesut Ozgokce ◽  
...  
Keyword(s):  
Prospective Study ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Sperm Count ◽  
Shear Wave Elastography ◽  
Non Invasive ◽  
Sperm Counts ◽  
Wave Technique ◽  
The Mean

Aims: To evaluate the reliability of testicular stiffness quantification using shear wave elastography in predicting the fertility potential of males and for the pre-diagnosis of disorders based upon sperm quantification. Material and methods: One hundred males between the ages of 19-49 years (mean age of 28.77±6.11), ninety of whom with complaints of infertility, were enrolled in this prospective study. Scrotal grey-scale, Doppler ultrasound (US), and mean testicular shear wave velocity quantifications (SWVQs) were performed. The volumes of testes, as well as the grade of varicocele if present, were recorded. The mean shear wave velocity values (SWVVs) of each testis and a mean testicular SWVV for each patient were calculated. The semen-analyses of patients were consecutively performed. Results: There were significant negative correlations between the mean testicular SWVVs of patients and their sperm counts or the testis volumes (r=-0.399, r=-0.565; p<0.01, respectively). A positive correlation was found between testicular volumes and sperm counts (r=0.491, p<0.01). The cut-off values regarding mean testicular SWVV to distinguish normal sperm count from azoospermia and oligozoospermia were 1.465 m/s (75.0% sensitivity and 75.0% specificity) and 1.328 m/s (64.3% sensitivity and 68.2% specificity), respectively, and the value to distinguish oligozoospermia from azoospermia was 1.528 m/s (66.7% sensitivity, 60.7% specificity). Conclusion: The mean testicular SWVQ using the ARFI shear wave technique was a reliable, non-invasive and acceptably stable method for predicting male infertility, especially related to sperm count issues. 

scholarly journals Reliability of shear wave elastography ultrasound to assess the supraspinatus tendon: An intra and inter-rater in vivo study

2019 ◽  
Vol 12 (1) ◽  
pp. 18-23 ◽  
Author(s):  
Lisa Hackett ◽  
Ricardo Aveledo ◽  
Patrick H Lam ◽  
George AC Murrell
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Acoustic Radiation ◽  
Intraclass Correlation ◽  
Shear Wave Elastography ◽  
Radiation Force ◽  
Supraspinatus Tendon ◽  
Acoustic Radiation Force Impulse ◽  
The Mean

Introduction Shear wave elastography ultrasound is a relatively new technique that evaluates the tissue elasticity by applying an acoustic radiation force impulse. It is undetermined how reliable this modality is in assessing rotator cuff tendons. The aim of this study, therefore, was to evaluate the reliability of shear wave elastography ultrasound to assess the stiffness of normal and tendinopathic supraspinatus tendons. Methods An inter- and intra-rater reliability trial was carried out using shear wave elastography to assess the supraspinatus tendon at its distal insertion, by measuring shear wave velocity and elasticity. Twenty participants with a mean age of 37 (21–69) years old were evaluated. Ten subjects with normal supraspinatus tendon and 10 subjects with tendinopathic tendon were selected. The Virtual Touch Imaging Quantification program was used to generate the acoustic radiation force impulse and to obtain the elastography data. Three raters with different experience in conventional ultrasound were used for the inter-rater trial in normal tendons and the most experienced rater examined all subjects for the intra-rater reliability evaluation. Each rater obtained three readings in three different examinations per subject over a one-week period. Results The mean (±SEM) shear wave velocity for the normal supraspinatus tendon was 9.96 ± 0.02 m/s (=297 kPa), while in the tendinopathic supraspinatus tendon was 8.3 ± 0.2 m/s (=207 kPa) (p < 0.001). The intra-rater trial agreement was excellent, with an intraclass correlation coefficient = 0.96. In the inter-rater testing, the mean shear wave velocity in normal tendons was 9.90 ± 0.07 m/s (=294 kPa), with intraclass correlation coefficient = 0.45. Conclusion Shear wave elastography ultrasound was able to show that tendinopathic tendons were less stiff than normal tendons. It was a reliable imaging technique to assess the supraspinatus tendon, especially when used by a single experienced musculoskeletal sonographer.

scholarly journals Determining the effects of excess weight on renal cortical stiffness in children and adolescents with point Shear Wave Elastography

2021 ◽  
Author(s):  
Zehra Filiz Karaman ◽  
Fatih Kardas
Keyword(s):  
Body Mass Index ◽  
Children And Adolescents ◽  
Shear Wave ◽  
Body Mass ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Shear Wave Elastography ◽  
Excess Weight ◽  
The Mean ◽  
Lean Children

Aim: To determine the early effects of excess weight on renal cortical stiffness in children and adolescents using point shear wave elastography (pSWE). Materials and methods: One hundred and forty-six overweight and obese children (43.2% male; mean age, 12.6±2.9 years: range 4.3-18) and 48 lean children (27.1% male: mean age, 12.4±3.4: range 4.8-18.9) were included in the study and control group, respectively. pSWE measurements of the two kidneys were performed. The mean value of shear wave velocity was compared between groups. Results: The mean shear wave velocity was 2.79±0.53 m/s for the control subjects and 3.09±0.59 m/s for the overweight-obese subjects. The differences between the two groups were sta-tistically significant (p=0.001). There was no correlation between shear wave velocity and age or depth. A positive correlation was found between shear wave velocity and body mass index, body mass index-standard deviation score. Conclusion: Renal cortical stiffness was higher in children with excess weight than in lean children. This study is the first attempt at applying pSWE to investigate the early adverse effects of excess weight.

scholarly journals Calibrating a new attenuation curve for the Dead Sea region using surface wave dispersion surveys in sites damaged by the 1927 Jericho earthquake

Solid Earth ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 379-390 ◽  
Author(s):  
Yaniv Darvasi ◽  
Amotz Agnon
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Dead Sea ◽  
Attenuation Curve ◽  
Surface Wave Dispersion ◽  
Near Surface ◽  
Moderate Seismicity ◽  
Local Point ◽  
The Dead

Abstract. Instrumental strong motion data are not common around the Dead Sea region. Therefore, calibrating a new attenuation equation is a considerable challenge. However, the Holy Land has a remarkable historical archive, attesting to numerous regional and local earthquakes. Combining the historical record with new seismic measurements will improve the regional equation. On 11 July 1927, a rupture, in the crust in proximity to the northern Dead Sea, generated a moderate 6.2 ML earthquake. Up to 500 people were killed, and extensive destruction was recorded, even as far as 150 km from the focus. We consider local near-surface properties, in particular, the shear-wave velocity, as an amplification factor. Where the shear-wave velocity is low, the seismic intensity far from the focus would likely be greater than expected from a standard attenuation curve. In this work, we used the multichannel analysis of surface waves (MASW) method to estimate seismic wave velocity at anomalous sites in Israel in order to calibrate a new attenuation equation for the Dead Sea region. Our new attenuation equation contains a term which quantifies only lithological effects, while factors such as building quality, foundation depth, topography, earthquake directivity, type of fault, etc. remain out of our scope. Nonetheless, about 60 % of the measured anomalous sites fit expectations; therefore, this new ground-motion prediction equation (GMPE) is statistically better than the old ones. From our local point of view, this is the first time that integration of the 1927 historical data and modern shear-wave velocity profile measurements improved the attenuation equation (sometimes referred to as the attenuation relation) for the Dead Sea region. In the wider context, regions of low-to-moderate seismicity should use macroseismic earthquake data, together with modern measurements, in order to better estimate the peak ground acceleration or the seismic intensities to be caused by future earthquakes. This integration will conceivably lead to a better mitigation of damage from future earthquakes and should improve maps of seismic hazard.

scholarly journals Multi-method site characterization to verify the hard rock (Site Class A) assumption at 25 seismograph stations across Eastern Canada

2021 ◽  
pp. 875529302110010
Author(s):  
Sameer Ladak ◽  
Sheri Molnar ◽  
Samantha Palmer
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Hard Rock ◽  
Site Characterization ◽  
Eastern Canada ◽  
Site Class ◽  
Paleozoic Rock ◽  
Rock Types ◽  
Site Period

Site characterization is a crucial component in assessing seismic hazard, typically involving in situ shear-wave velocity ( VS) depth profiling, and measurement of site amplification including site period. Noninvasive methods are ideal for soil sites and become challenging in terms of field logistics and interpretation in more complex geologic settings including rock sites. Multiple noninvasive active- and passive-seismic techniques are applied at 25 seismograph stations across Eastern Canada. It is typically assumed that these stations are installed on hard rock. We investigate which site characterization methods are suitable at rock sites as well as confirm the hard rock assumption by providing VS profiles. Active-source compression-wave refraction and surface wave array techniques consistently provide velocity measurements at rock sites; passive-source array testing is less consistent but it is our most suitable method in constraining the rock VS. Bayesian inversion of Rayleigh wave dispersion curves provides quantitative uncertainty in the rock VS. We succeed in estimating rock VS at 16 stations, with constrained rock VS estimates at 7 stations that are consistent with previous estimates for Precambrian and Paleozoic rock types. The National Building Code of Canada uses solely the time-averaged shear-wave velocity of the upper 30 m ( VS30) to classify rock sites. We determine a mean VS30 of ∼ 1600 m/s for 16 Eastern Canada stations; the hard rock assumption is correct (>1500 m/s) but not as hard as often assumed (∼2000 m/s). Mean variability in VS30 is ∼400 m/s and can lead to softer rock classifications, in particular, for Paleozoic rock types with lower average rock VS near the hard/soft rock boundary. Microtremor and earthquake horizontal-to-vertical spectral ratios are obtained and provide site period classifications as an alternative to VS30.

Sign in / Sign up

Export Citation Format

Share Document