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 Evaluation of the possibilities of shear wave elastography for differentiation of lymphomatous and reactive changes of superficial lymph nodes

2020 ◽  
Vol 15 (1) ◽  
pp. 59-64
Author(s):  
E. V. Kovaleva ◽  
T. Yu. Danzanova ◽  
G. T. Sinyukova ◽  
E. A. Gudilina ◽  
P. I. Lepedatu ◽  
...  
Keyword(s):  
Differential Diagnosis ◽  
Lymph Nodes ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Ultrasound Elastography ◽  
Wave Velocities ◽  
Shear Wave Velocities ◽  
Reactive Changes ◽  
Hodgkin's Lymphomas

Objective: to evaluate the possibilities of ultrasound elastography for differentiation of reactive and lymphomatous superficial lymph nodes (LN).Materials and methods. The prospective study included 138 patients with enlarged superficial LN. Based on a previous histological examination, patients were divided into two groups: 1st group (n = 108) – patients with non-Hodgkin’s lymphomas and Hodgkin’s lymphoma; 2nd (n = 30) – patients with reactive (inflammatory) changes in superficial LN. All patients underwent ultrasound elastography of the enlarged LN using ARFI technology.Results. According to the results of ultrasound elastography, the average, minimum, and maximum shear wave velocities for enlarged LN in lymphoma (1st group) were 2.616 ± 0.684; 1.980 ± 0.557 and 3.351 ± 0.987 m / s, respectively; for LN with reactive changes (2nd group) – 1.704 ± 0.223; 1.414 ± 0.209 and 2.027 ± 0.261 m / s, respectively. Thus, the average, minimum, and maximum values of shear wave velocities significantly different between the groups (p ˂0.001). The cut off values of the average shear wave velocity in the differential diagnosis of lymphoma and hyperplasia are determined at the level of 2.05 m / s, with a sensitivity of 88.5 %, specificity of 100 %, and AUC of 0.942 (p ˂0.001).Conclusion. Ultrasound elastography demonstrated statistically significant differences in shear wave velocity in the enlarged superficial LN in lymphoma and in inflammatory processes that can be used as a preliminary non-invasive differential diagnosis of enlarged superficial LN in these conditions. 

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 Successful experience in the use of ultrasound elastography in the differentiating of lymphomatous and metastatic superficial lymphadenopathy

2020 ◽  
Vol 15 (2) ◽  
pp. 42-48
Author(s):  
E. V. Kovaleva ◽  
T. Yu. Danzanova ◽  
G. T. Sinyukova ◽  
E. A. Gudilina ◽  
P. I. Lepedatu ◽  
...  
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Acoustic Radiation ◽  
Radiation Force ◽  
Area Ratio ◽  
Ultrasound Elastography ◽  
Acoustic Radiation Force Impulse ◽  
Tissue Imaging ◽  
Hodgkin's Lymphomas

The objective: to evaluate the possibilities of ARFI technology (Acoustic Radiation Force Impulse), including Virtual Touch™ Tissue Imaging (VTI) and Virtual Touch™ Tissue Quantification (VTQ) for differentiation of lymphomatous and metastatic superficial lymphadenopathy.Materials and methods. The prospective study included 138 patients with enlarged superficial lymph nodes (LN). Based on a previous histological examination, patients were divided into two groups: 1st group (n = 108) – patients with non-Hodgkin’s lymphomas and Hodgkin’s lymphoma; 2nd group (n = 30) – patients with metastasis of solid tumors in superficial LN. All patients underwent ultrasound elastography of the enlarged LN using ARFI technology. In VTI study the Area Ratio parameter was evaluated, and the minimum and average values of the shear wave velocity were estimated in VTQ study.Results. According to the results of VTI study the Area Ratio parameter for enlarged LN in lymphoma (1st group) and for metastatic lymphadenopathy (2 nd group) were 1.031 ± 0.197 and 0.851 ± 0.15, respectively (p = 0.000009). The cut off value of the Area Ratio parameter was 0.901 with sensitivity, specificity and accuracy 80.6, 70.0 and 78.8 %, respectively. Minimum values of shear wave velocities for 1st and 2 nd groups were 1.980 ± 0.557 and 2.214 ± 0.367 m/s, respectively (p = 0.032). The cut off values of the average shear wave velocity in the differentiating of lymphomatous and metastatic lymphadenopathy are determined at the level of 2.00 m/s, with sensitivity of 70.0 %, specificity of 59.3 %, and accuracy of 61.6 %.Conclusion. Ultrasound elastography with ARFI technology demonstrated statistically significant differences in the Area Ratio parameter and in the minimum shear wave velocity in the enlarged superficial LN in lymphoma and with metastasis that can be used as a preliminary non-invasive differential diagnosis of enlarged superficial LN in these conditions. Moreover, the Area Ratio parameter has a statistically more significant effect on differentiating of lymphomatous and metastatic lymphadenopathy.

scholarly journals B mode ultrasonography and elastography in the evaluation of the pectineus muscle in dogs with hip dysplasia

2020 ◽  
Vol 44 (5) ◽  
pp. 1142-1149
Author(s):  
Pedro Paulo ROSSIGNOLI ◽  
Marcus Antônio Rossi FELICIANO ◽  
Bruno Watanabe MINTO ◽  
Marjury Cristina MARONEZI ◽  
Ricardo Andres Ramirez USCATEGUI ◽  
...  
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Hip Dysplasia ◽  
Tissue Stiffness ◽  
Sonographic Appearance ◽  
Wave Velocities ◽  
Shear Wave Velocities ◽  
Arfi Elastography ◽  
Healthy Dogs

The goal of this study was to describe and compare B mode and elastographic characteristics of the pectineus muscle of healthy dogs with dysplastic dogs. Thirty-one dogs (62 limbs) with hip dysplasia and 17 nondysplastic dogs (34 limbs) were evaluated. The hip dysplasia score was defined according to the Fédération Cynologique Internationale. Using B mode, echotexture and echogenicity of different regions of the pectineus muscle were evaluated. By means of ARFI elastography, qualitative (elastogram) and quantitative (shear wave velocity) tissue stiffness was assessed. B mode findings demonstrated a hyperechoic and heterogeneous pattern of the pectineus tissue in dogs with hip dysplasia, with compromised muscular delimitation and loss of its normal sonographic appearance, indicating the disease (P < 0.001). In the elastogram, it was observed that dogs with hip dysplasia showed less deformable pectineus muscle, with red colors (rigid). In quantitative evaluation, the different regions evaluated presented similar shear wave velocities; in dysplastic patients, shear wave velocities were higher compared to nondysplastic animals, with values higher than 2.85 m/s being strong indicators of the disease. Values of shear wave velocity were also influenced by the grade of dysplasia and age of the patients; however, there was no correlation with the depth of the evaluated area or body weight. It was concluded that pectineus muscle in dogs with hip dysplasia presents B mode and elastographic changes when compared to normal animals, demonstrating that these techniques might aid the evaluation of diseased dogs.

Mapping Fundamental-Mode Site Periods and Amplifications from Thick Sediments: An Example from the Jackson Purchase Region of Western Kentucky, Central United States

2021 ◽  
Author(s):  
Yichuan Zhu ◽  
Zhenming Wang ◽  
N. Seth Carpenter ◽  
Edward W. Woolery ◽  
William C. Haneberg
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Fundamental Mode ◽  
Site Response ◽  
Velocity Profiles ◽  
Wave Velocities ◽  
Shear Wave Velocities ◽  
Jackson Purchase ◽  
Western Kentucky

ABSTRACT V S 30 is currently used as a key proxy to parameterize site response in engineering design and other applications. However, it has been found that VS30 is not an appropriate proxy, because it does not reliably correlate with site response. Therefore, the VS30-based National Earthquake Hazards Reduction Program site maps may not capture regional site responses. In earthquake engineering, site resonance, which can be characterized by the fundamental mode with a site period (Tf) and its associated peak amplification (A0), is the primary site-response concern. Mapping Tf and A0 is thus essential for accurate regional seismic hazard assessment. We developed a 3D shear-wave velocity model for the Jackson Purchase Region of western Kentucky, based on shear-wave velocity profiles interpreted from seismic reflections and refractions, mapped geologic units, and digital-elevation-model datasets. We generated shear-wave velocity profiles at grid points with 500 m spacing from the 3D model and performed 1D linear site-response analyses to obtain Tf and A0, which we then used to construct contour maps for the study area. Our results show that Tf and A0 maps correlate with the characteristics of regional geology in terms of sediment thicknesses and their average shear-wave velocities. We also observed a strong dependency of A0 on bedrock shear-wave velocities. The mapped Tf and A0 are consistent with those estimated from borehole transfer functions and horizontal-to-vertical spectral ratio analyses at broadband and strong-motion stations in the study area. Our analyses also demonstrate that the depth to bedrock (Zb) is correlated to Tf, and the average sediment shear-wave velocity (VS-avg) is correlated to A0. This implies that Zb and VS-avg may be considered as paired proxies to parameterize site resonance in the linear-elastic regime.

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 Shear Wave Ultrasonic Elastometry in Diagnostics of Metastatic Lymph Nodes in Neck Thyroid Cancer

2021 ◽  
Vol 4 (4) ◽  
pp. 50-55
Author(s):  
E. A. Gudilina ◽  
T. Yu. Danzanova ◽  
P. I. Lepedatu ◽  
G. T. Sinyukova
Keyword(s):  
Differential Diagnosis ◽  
Thyroid Cancer ◽  
Lymph Nodes ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Soft Tissues ◽  
Statistical Significance ◽  
Metastatic Lesions ◽  
Significant Difference

Purpose: Determination of informative value of a new method of ultrasound tomography, based on the properties of elasticity of soft tissues, in the differential diagnosis of metastatic lesions of the lymph nodes of the neck thyroid cancer.Material and methods: To assess the capabilities of shear wave ultrasound elastometry in the diagnosis of metastatic lesions of the lymph nodes in thyroid cancer, a study was carried out with 45 patients with suspected thyroid cancer. The work was performed by devices Acuson S2000 Siemens, Avius hi vision Hitachi using a linear sensor with a frequency of 5–12 MHz. For each object of the study, from 5 to 10 measurements of the shear wave velocity in m / s were made, depending on the size of the lymph nodes.Results: Reliable results were obtained in the group of altered lymph nodes (statistical significance p < 0.05). Interquartile intervals and the most common values of shear wave velocities do not overlap: in metastases — 2.20– 3.36 m/s, with hyperplasia of lymph nodes — 0.70–1.88 m/s, and medians show a significant difference in velocities: metastases — 3.00 m/s, hyperplastic lymph nodes 1.38 m/s.Conclusions: Shear wave elastography objectifies ultrasound studies, obtaining specific indicators of shear wave velocity in the areas of interest, and can be used as an additional diagnostic tool in the differential diagnosis of metastatic and hyperplastic lymph nodes.

scholarly journals Эластографическая характеризация рака яичка (морфологические и технические аспекты)

2017 ◽  
pp. 25-39
Keyword(s):  
Testicular Cancer ◽  
Germ Cell ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Germ Cell Tumors ◽  
Shear Wave Elastography ◽  
Ultrasound Elastography ◽  
Nonseminomatous Germ Cell Tumors ◽  
Multiparametric Ultrasound

Проведена ультразвуковая эластографическая оценка злокачественных опухолей яичка у 31 пациента в возрасте от 19 до 65 лет. Во всех случаях было одностороннее поражение. Во всех случаях диагноз подтвержден морфологически (семинома - 18 (58,1%), эмбриональная карцинома - 5 (16,1%), смешанные герминогенные опухоли - 7 (22,6%), спермоцитарная семинома - 1 (3,2%)). Пациенты были разделены на группы в зависимости от морфологических видов опухоли (семинома (n = 18) и несеминомные герминогенные опухоли (n = 12, в 2 случаях семинома была одним из компонентов смешанной герминогенной опухоли) (1 случай спермоцитарной семиномы был исключен из этой части анализа); тератома как компонент смешанной герминогенной опухоли (n = 6) и остальные герминогенные опухоли (n = 25)). Режим эластографии сдвиговой волной использовался после предварительной серошкальной визуализации яичек на аппаратах Aplio 500 (Toshiba, Япония) и Aixplorer (Supersonic Imagine, Франция) (линейные датчики 5-14 и 4-15 МГц соответственно). Технические аспекты: различия между измерениями значений модуля Юнга в опухолях яичка на аппарате (1) Aplio 500 и аппарате (2) Aixplorer недостоверны (P = 0,95). Корреляция между значениями модуля Юнга, полученными на двух приборах, высокая (rs = 0,86, P = 0,0137). Значения модуля Юнга в опухолях яичка достоверно выше по сравнению с эхографически неизмененной паренхимой ипсилатерального яичка (P = 0,0017 для указанных сравнений на двух аппаратах) и паренхимой эхографически неизмененного контрлатерального яичка (P = 0,0017 для указанных сравнений на двух аппаратах) на фоне отсутствия достоверности различий между значениями модуля Юнга в двух яичках (неизмененные участки ипсилатерального яичка и паренхима среднего сегмента контрлатерального яичка) (P = 0,4057 и P = 0,8480 для аппаратов 1 и 2 соответственно). Морфологические аспекты (аппарат Aixplorer): медиана Emean в группе семиномы (n = 18) составила 110,3 кПа, 25-75-й процентили - 77,6-159,0 кПа, 5-95-й процентили - 16.5- 222,1 кПа, минимальное - максимальное значения - 15,3-241,4 кПа; в группе несеминомных герминогенных опухолей (n = 12) - 109,9 кПа, 83,0-129,0 кПа, 55.5- 156,8 кПа, 54,2-157,8 кПа (различия недостоверны при P=0,9325). Отсутствие достоверности различий также было определено при сравнении смешанных герминогенных опухолей, в составе которых была тератома, и остальных опухолей (P = 0,5823). Различия значений индексов жесткости (индекс жесткости 1 - отношение значений Emean в областях опухоли и эхографически неизмененной паренхимы ипсилатерального яичка, индекс жесткости 2 - отношение значений Emean в областях опухоли и паренхимы эхографически неизмененного контрлатерального яичка, индекс жесткости 3 - внутриопухолевый индекс жесткости с учетом участков с максимальной и минимальной жесткостью внутри объемного образования) у пациентов с семиномами и несеминомными герминогенными опухолями не выявлены. Ключевые слова: мультипараметрическая ультразвуковая диагностика, ультразвуковая эластография, эластография сдвиговой волной, жесткость, модуль Юнга, скорость сдвиговой волны, рак яичка, семинома, несеминомные герминогенные опухоли, multiparametric ultrasound, ultrasound elastography, shear wave elastography, stiffness, Young’s modulus, shear wave velocity, testicular cancer, seminoma, nonseminomatous germ cell tumors

Shear‐wave logging to enhance seismic modeling

Geophysics ◽  
1991 ◽  
Vol 56 (12) ◽  
pp. 2129-2138 ◽  
Author(s):  
M. A. Payne
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Field Data ◽  
Compressional Wave ◽  
Oil Sand ◽  
Wave Velocities ◽  
Shear Wave Velocities ◽  
Amplitude Versus Offset ◽  
Amplitude Versus

In an effort to understand better the amplitude variation with offset for reflections from an oil sand and the sensitivity of the AVO response to shear‐wave velocity variations, I studied synthetic and field gathers collected from an onshore field in the Gulf of Mexico basin. A wave‐equation‐based modeling program generated the synthetic seismic gathers using both measured and estimated shear‐wave velocities. The measured shear‐wave velocities came from a quadrupole sonic tool. The estimated shear‐wave velocities were obtained by applying published empirical and theoretical equations which relate shear‐wave velocities to measured compressional‐wave velocities. I carefully processed the recorded seismic data with a controlled‐amplitude processing stream. Comparison of the synthetic gathers with the processed field data leads to the conclusion that the model containing the measured shear‐wave velocities matches the field data much better than the model containing the estimated shear‐wave velocities. Therefore, existing equations which relate shear‐wave velocities to compressional‐wave velocities yield estimates which are not sufficiently accurate for making quantitative comparisons of synthetic and field gathers. Even small errors in the shear‐wave velocities can have a large impact on the output. Such errors can lead to an incomplete and perhaps inaccurate understanding of the amplitude‐versus‐offset response. This situation can be remedied by collecting shear‐wave data for use in amplitude‐versus‐offset modeling, and for building databases to generate better shear‐wave velocity estimator equations.

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