scholarly journals Parameter Identification for Ultrasound Shear Wave Elastography Simulation

2021 ◽  
Vol 7 (1) ◽  
pp. 35-38
Author(s):  
M. Neidhardt ◽  
J. Ohlsen ◽  
N. Hoffmann ◽  
A. Schlaefer

Abstract Elasticity of soft tissue is a valuable information to physicians in treatment and diagnosis of diseases. The elastic properties of tissue can be estimated with ultrasound (US) shear wave imaging (SWEI). In US-SWEI, a force push is applied inside the tissue and the resulting shear wave is detected by high-frequency imaging. The properties of the wave such as the shear wave velocity can be mapped to tissue elasticity. Commonly, wave features are extracted by tracking the peak of the shear wave, estimating the phase velocity or with machine learning methods. To tune and test these methods, often simulation data is employed since material properties and excitation can be accurately controlled. Subsequent validation on real US-SWEI data is in many cases performed on tissue phantoms such as gelatine. Clearly, validation performance of these procedures is dependent on the accuracy of the simulated tissue phantom and a thorough comparison of simulation and experimental data is needed. In this work, we estimate wave parameters from 400 US-SWEI data sets acquired in various homogeneous gelatine phantoms. We tune a linear material model to these parameters. We report an absolute percentage error for the shear wave velocity between simulation and phantom experiment of <2.5%. We validate our material model on unknown gelatine concentrations and estimate the shear wave velocity with an error <3.4% for in-range concentrations indicating that our material model is in good agreement with US-SWEI measurements.

2017 ◽  
Vol 45 (1) ◽  
pp. 129-136 ◽  
Author(s):  
Atsushi Yamamoto ◽  
Yoshiki Yamakoshi ◽  
Takashi Ohsawa ◽  
Hitoshi Shitara ◽  
Tsuyoshi Ichinose ◽  
...  

Author(s):  
Hiroaki Noro ◽  
Naokazu Miyamoto ◽  
Naotoshi Mitsukawa ◽  
Toshio Yanagiya

AbstractLower stiffness of the medial longitudinal arch is reportedly a risk factor for lower leg disorders. The plantar aponeurosis is considered essential to maintaining the medial longitudinal arch. It is therefore expected that medial longitudinal arch stiffness is influenced by plantar aponeurosis stiffness. However, this has not been experimentally demonstrated. We examined the relationship between the plantar aponeurosis stiffness and medial longitudinal arch stiffness in humans in vivo. Thirty young subjects participated in this study. The navicular height and shear wave velocity (an index of stiffness) of the plantar aponeurosis were measured in supine and single-leg standing positions, using B-mode ultrasonography and shear wave elastography, respectively. The medial longitudinal arch stiffness was calculated based on body weight, foot length, and the difference in navicular height between the supine and single-leg standing conditions (i. e., navicular drop). Shear wave velocity of the plantar aponeurosis in the supine and single-leg standing positions was not significantly correlated to medial longitudinal arch stiffness (spine: r=−0.14, P=0.45 standing: r=−0.16, P=0.41). The findings suggest that the medial longitudinal arch stiffness would be strongly influenced by the stiffness of foot structures other than the plantar aponeurosis.


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


2021 ◽  
Vol 21 (85) ◽  
pp. e86-e94
Author(s):  
Lana H Gimber ◽  
◽  
L. Daniel Latt ◽  
Chelsea Caruso ◽  
Andres A. Nuncio Zuniga ◽  
...  

Aim of study: Most sprained lateral ankle ligaments heal uneventfully, but in some cases the ligament’s elastic function is not restored, leading to chronic ankle instability. Ultrasound shear wave elastography can be used to quantify the elasticity of musculoskeletal soft tissues; it may serve as a test of ankle ligament function during healing to potentially help differentiate normal from ineffective healing. The purpose of this study was to determine baseline shear wave velocity values for the lateral ankle ligaments in healthy male subjects, and to assess inter-observer reliability. Material and methods: Forty-six ankles in 23 healthy male subjects aged 20–40 years underwent shear wave elastography of the lateral ankle ligaments performed by two musculoskeletal radiologists. Each ligament was evaluated three times with the ankle relaxed by both examiners, and under stress by a single examiner. Mean shear wave velocity values were compared for each ligament by each examiner. Inter-observer agreement was evaluated. Results: The mean shear wave velocity at rest for the anterior talofibular ligament was 2.09 ± 0.3 (range 1.41–3.17); and for the calcaneofibular ligament 1.99 ± 0.36 (range 1.29–2.88). Good inter-observer agreement was found for the anterior talofibular ligament and calcaneofibular ligament shear wave velocity measurements with the ankle in resting position. There was a significant difference in mean shear wave velocities between rest and stressed conditions for both anterior talofibular ligament (2.09 m/s vs 3.21 m/s; p <0.001) and calcaneofibular ligament (1.99 m/s vs 3.42 m/s; p <0.0001). Conclusion: Shear wave elastography shows promise as a reproducible method to quantify ankle ligament stiffness. This study reveals that shear waves velocities of the normal lateral ankle ligaments increased with applied stress compared to the resting state.


Choonpa Igaku ◽  
2018 ◽  
Vol 45 (4) ◽  
pp. 439-443
Author(s):  
Naoki HAMAZAKI ◽  
Naohisa SHIOYA ◽  
Teruhiko IMAI ◽  
Kouji HAYASHIDA ◽  
Motoaki YASUKAWA ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Joanna Sichitiu ◽  
Jean-Yves Meuwly ◽  
David Baud ◽  
David Desseauve

AbstractThis study aims to evaluate the feasibility and clinical interest of shear wave elastography, by quantitatively estimating the baseline stiffness of the myometrium before and after placental expulsion. We conducted a prospective cohort study of women at term, without known risk factors for postpartum hemorrhage, who gave birth via spontaneous labor in our tertiary center. Myometrium tonicity was evaluated based on measurements of shear wave speed (SWS) in the anterior uterine corpus. All data points were collected by a single operator. Measurements were carried out at three different time points: after fetal delivery (T1), after placental delivery (T2) and 30 min after placental delivery (T3). Our primary objective was to assess the feasibility of this new imaging technique. Ten valid SWS measurements obtained at each of the three different time points were considered as a positive primary outcome. Our secondary objectives were to evaluate the difference in median myometrial shear wave velocity between each time point, as well as to determine the correlation between myometrial shear wave velocity and patients’ characteristics. 38 women were recruited during the study period, of whom 34 met the study criteria. 1017 SWS measurements were obtained. The median time to perform measurements was 16 s for one value, and 2 min 56 s for ten. For 11 women (32%) it was not possible to achieve ten SWS at T1 as placental expulsion immediately followed the birth of the newborn. One patient experienced placental retention and only measurements at T1 were performed. For all other patients, we were successfully able to obtain all measures as intended. There was no difference in the mean shear wave speed between the three time points. After adjustments for confounders, we observed a significant correlation for total blood loss (correlation coefficient = − 0.26, p < 0.001, units of oxytocin (correlation coefficient = − 0.34, p = 0.03), and newborn weight (correlation coefficient = − 0.08, p = 0.001). It is feasible to assess uterine tonicity by shear wave imaging, after placental expulsion. We did not observe a variance in uterine tonicity between the three time points. Women who had higher blood loss, received more units of oxytocin and/or those with newborns of a higher weight exhibited lower shear wave speed measures.


С января по август 2017 г. выполнены ультразвуковые исследования лимфатических узлов у 51 человека (23 мужчины и 28 женщин) в возрасте 23-86 лет с цитологически верифицированным диагнозом “злокачественная меланома кожи”. У всех пациентов заподозрены метастатические изменения в лимфатических узлах различной локализации по данным серошкальной эхографии и допплерографических методик. Исследования были выполнены на аппарате Aplio 500 (Toshiba, Япония) линейным датчиком 7-18 МГц. В первую группу вошел 21 человек с метастазами в регионарных лимфатических узлах, во вторую - 30 пациентов с гиперплазией лимфоидноретикулярной ткани. Значения модуля Юнга для метастатически измененных лимфатических узлов составили 101,8 кПа (медиана), 14,0-164,5 кПа (2,5-97,5-й процентили), для гиперплазированных лимфатических узлов - 15,0 кПа, 7,2-56,8 кПа соответственно. Значения модуля Юнга в метастатически измененных лимфатических узлах не коррелировали ни с уровнем инвазии первичной опухоли (меланомы) по Кларку, ни с локализацией метастазов (подмышечные, шейные, паховые лимфатические узлы). Выявлены значимые различия в значениях модуля Юнга между метастатически измененными и гиперплазированными лимфатическими узлами у пациентов с меланомой кожи (P 0,0001). Наилучшие показатели диагностической информативности в выявлении метастатического поражения лимфатических узлов при меланоме кожи достигнуты при пороговом значении модуля Юнга 22,7 кПа (чувствительность - 86%, специфичность - 77%, AUC - 0,916). Ключевые слова: ультразвуковая эластография, эластография сдвиговой волной, злокачественная меланома кожи, уровень инвазии по Кларку, толщина по Бреслоу, лимфатические узлы, модуль Юнга, скорость сдвиговой волны, ultrasound elastography, shear wave elastography, cutaneous malignant melanoma, Clark level of invasion, Breslow thickness, lymph nodes, Young’s modulus, shear wave velocity


Author(s):  
E. V. Kovaleva ◽  
E. A. Gudilina ◽  
T. Yu. Danzanova ◽  
G. T. Sinyukova ◽  
P. I. Lepedatu

Purpose: To evaluate the capabilities of ultrasound elastography in assessing the effectiveness of treatment of patients with special lesions of peripheral lymph nodes in lymphoproliferative lesions.Material and methods: To evaluate the capabilities of ultrasound elastography in assessing the effectiveness of treatment, an ultrasound study was carried out for 93 patients with lesions of peripheral lymph nodes with lymphoma in dynamics before treatment and after 2/3 courses of chemotherapy using Acoustic Force Radiation Impulse (ARFI — shear wave elastography) and eSie Touch (compression elastography).Results: Assessment of the dynamics of the average, minimum and maximum values of the shear wave velocity showed statistically significant differences. The most reliable changes were recorded when assessing the average and maximum indicators of the shear wave velocity (p = 0.0000001). Also, after two / three cycles of chemotherapy, the indicator X, XX m/s (p = 0.00001) was significantly less frequent, which was previously detected in the LN with the most rigid structure. Compression ultrasound elastography revealed softening of the LN structure in the form of an increase in the frequency of occurrence of I and II elastotypes.Conclusions: Our study confirms that ultrasound elastography allows, in a short time and without negative ionizing effects on the patient, to assess the effectiveness of the selected chemotherapy routes.


2018 ◽  
Vol 1 (1) ◽  
pp. 27 ◽  
Author(s):  
Flaviu Bob ◽  
Iulia Grosu ◽  
Ioan Sporea ◽  
Simona Bota ◽  
Alina Popescu ◽  
...  

Aim: To analyze the relationship between shear wave velocity in the kidney measured by point shear wave elastography using Virtual Touch Quantification (VTQ) (Siemens Acuson S2000) and histological parameters obtained from renal biopsies, in patients with chronic glomerulonephritis (CGN).Material and methods: The study group included 20 patients (mean age 47.95±13.59 years) with different types of CGN, that had underwent renal biopsy and 57 normal controls (mean age 38.07±17.32 years). In all patients, five valid stiffness measurements were obtained in each kidney, with the patient in lateral decubitus. Regarding the histological results, we assessed the presence or absence of glomerulosclerosis, interstitial fibrosis, and arteriolo-hyalinosis.Results: In patients with CGN we obtained the following mean values of VTQ values: right kidney: 2.12±0.81 m/s, left kidney 1.65±0.54 m/s, while in the normal controls significantly higher VTQ values were obtained: right kidney 2.69±0.72 m/s (p=0.004), left kidney 2.48±0.73 m/s (p<0.0001). In patients with CGN no statistically significant correlations between VTQ values and eGFR (r=0.37, p=0.12) or proteinuria (r=0.2, p=0.37) were found. We found significantly lower VTQ values in patients with interstitial fibrosis (1.46 vs. 1.99 m/s, p<0.05) and also in patients with arteriolo-hyalinosis (1.55 vs. 2.47 m/s, p<0.05).Conclusion: Our pilot study shows that shear wave velocity values in patients with CGN are significantly lower compared to normal controls, and there is a tendency to decrease with the decrease of eGFR, with the presence of interstitial fibrosis and of arteriolo-hyalinosis.


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