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Shear wave

Yuan Feng, Mo Zhu, Suhao Qiu, Ping Shen, Shengyuan Ma, Xuefeng Zhao, Chun-Hong Hu, Liang Guo
An electromagnetic actuator was designed for magnetic resonance elastography (MRE). The actuator is unique in that it is simple, portable, and capable of brain, abdomen, and phantom imagings. A custom-built control unit was used for controlling the vibration frequency and synchronizing the trigger signals. An actuation unit was built and mounted on the specifically designed clamp and holders for different imaging applications. MRE experiments with respect to gel phantoms, brain, and liver showed that the actuator could produce stable and consistent mechanical waves...
April 18, 2018: Magnetic Resonance Imaging
Aziz Asadollahi, Lev Khazanovich
The emergence of ultrasonic dry point contact (DPC) transducers that emit horizontal shear waves has enabled efficient collection of high-quality data in the context of a nondestructive evaluation of concrete structures. This offers an opportunity to improve the quality of evaluation by adapting advanced imaging techniques. Reverse time migration (RTM) is a simulation-based reconstruction technique that offers advantages over conventional methods, such as the synthetic aperture focusing technique. RTM is capable of imaging boundaries and interfaces with steep slopes and the bottom boundaries of inclusions and defects...
April 11, 2018: Ultrasonics
Koichi Hamada, Satoshi Saitoh, Noriyuki Nishino, Daizo Fukushima, Yoshinori Horikawa, Shinya Nishida, Michitaka Honda
AIM: To evaluate the relationship between fibrosis and HCC after sustained virological response (SVR) to treatment for chronic hepatitis C (HCV). METHODS: This single-center study retrospectively evaluated 196 patients who achieved SVR after HCV infection. The associations of risk factors with HCC development after HCV eradication were evaluated using univariate and multivariate Cox proportional hazards regression models. RESULTS: Among the 196 patients, 8 patients (4...
2018: PloS One
Jagannath Devkota, Ki-Joong Kim, Paul R Ohodnicki, Jeffrey T Culp, David W Greve, Jonathan W Lekse
The integration of nanoporous materials such as metal organic frameworks (MOFs) with sensitive transducers can result in robust sensing platforms for monitoring gases and chemical vapors for a range of applications. Here, we report on an integration of the zeolitic imidazolate framework - 8 (ZIF-8) MOF with surface acoustic wave (SAW) and thickness shear mode quartz crystal microbalance (QCM) devices to monitor carbon dioxide (CO2) and methane (CH4) under ambient conditions. The MOF was directly coated on the Y-Z LiNbO3 SAW delay lines (operating frequency, f0 = 436 MHz) and AT-cut quartz TSM resonators (resonant frequency, f0 = 9 MHz) and the devices were tested for various gases in N2 under ambient conditions...
April 19, 2018: Nanoscale
Hyo Jin Kim, Sun Mi Kim, Bohyoung Kim, Bo La Yun, Mijung Jang, Yousun Ko, Soo Hyun Lee, Heeyeong Jeong, Jung Min Chang, Nariya Cho
We investigated addition of strain and shear wave elastography to conventional ultrasonography for the qualitative and quantitative assessment of breast masses; cut-off points were determined for strain ratio, elasticity ratio, and visual score for differentiating between benign and malignant masses. In all, 108 masses from 94 patients were evaluated with strain and shear wave elastography and scored for suspicion of malignancy, visual score, strain ratio, and elasticity ratio. The diagnostic performance between ultrasonography alone and ultrasonography combined with either type of elastography was compared; cut-off points were determined for strain ratio, elasticity ratio, and visual score...
April 18, 2018: Scientific Reports
Christoph A Reichel, Teresa Vincek, Donata Gellrich, Florian Schrötzlmair, Dirk Clevert, Pamela Zengel
OBJECTIVE: This study aims to answer whether Acoustic Radiation Force Impulse Imaging (ARFI) can reasonably be employed in initial examination and follow-up during therapy in patients with sialolithiasis, one of the most common non-malignant disorders of the salivary glands. METHODS: Mechanical tissue properties of affected and contralateral healthy salivary glands were analyzed by ARFI in 129 patients with sialolithiasis. In different subgroup analyses, ARFI shear wave velocity values were compared between healthy and diseased submandibular or parotid glands, salivary glands with calculi exhibiting different sizes, as well as before and after therapy...
April 18, 2018: Dento Maxillo Facial Radiology
Dong Ho Lee, Jeong Min Lee, Jung-Hwan Yoon, Yoon Jun Kim, Jeong-Hoon Lee, Su Jong Yu, Joon Koo Han
Purpose: To evaluate the prognostic value of liver stiffness (LS) measured using two-dimensional (2D) shear-wave elastography (SWE) in patients with hepatocellular carcinoma (HCC) treated by radiofrequency ablation (RFA). Methods: The Institutional Review Board approved this retrospective study and informed consent was obtained from all patients. A total of 134 patients with up to 3 HCCs ≤5 cm who had undergone pre-procedural 2D-SWE prior to RFA treatment between January 2012 and December 2013 were enrolled...
March 2018: Liver Cancer
Anna Pichiecchio, Francesco Alessandrino, Chandra Bortolotto, Alessandra Cerica, Cristina Rosti, Maria Vittoria Raciti, Marta Rossi, Angela Berardinelli, Giovanni Baranello, Stefano Bastianello, Fabrizio Calliada
The aim of this study was to determine muscle tissue elasticity, measured with shear-wave elastography, in selected lower limb muscles of patients affected by Duchenne muscular dystrophy (DMD) and to correlate the values obtained with those recorded in healthy children and with muscle magnetic resonance imaging (MRI) data from the same DMD children, specifically the pattern on T1-weighted (w) and short-tau inversion recovery (STIR) sequences. Five preschool DMD children and five age-matched healthy children were studied with shear-wave elastography...
April 13, 2018: Neuromuscular Disorders: NMD
Quinton W Guerrero, Helen Feltovich, Ivan M Rosado-Mendez, Lindsey C Carlson, Geng Li, Timothy J Hall
Imaging biomarkers based on quantitative ultrasound can offer valuable information about properties that inform tissue function and behavior such as microstructural organization (e.g., collagen alignment) and viscoelasticity (i.e., compliance). For example, the cervix feels softer as its microstructure remodels during pregnancy, an increase in compliance that can be objectively quantified with shear wave speed and therefore shear wave speed estimation is a potential biomarker of cervical remodeling. Other proposed biomarkers include parameters derived from the backscattered echo signal, such as attenuation and backscattered power loss, because such parameters can provide insight into tissue microstructural alignment and organization...
April 13, 2018: Ultrasound in Medicine & Biology
Wei-Wei Ren, Xiao-Long Li, Dan Wang, Bo-Ji Liu, Chong-Ke Zhao, Hui-Xiong Xu
OBJECTIVE: To evaluate a special kind of ultrasound (US) shear wave elastography for differential diagnosis of breast lesions, using a new qualitative analysis (i.e. the elasticity score in the travel time map) compared with conventional quantitative analysis. METHODS: From June 2014 to July 2015, 266 pathologically proven breast lesions were enrolled in this study. The maximum, mean, median, minimum, and standard deviation of shear wave speed (SWS) values (m/s) were assessed...
April 13, 2018: Clinical Hemorheology and Microcirculation
Ying Zhang, Hui-Xiong Xu, Chong-Ke Zhao, Xiao-Long Li, Xiao-Wan Bo, Ya-Ping He, Bo-Ji Liu, Dan Wang, Wei-Wei Ren
OBJECTIVE: To assess the performance of conventional high frequency ultrasound (US) and US elastography in diagnosis of complex cystic and solid breast lesions. METHODS: Ninety three lesions in 93 patients underwent conventional US and US elastography, including strain elastography, acoustic radiation force impulse (ARFI) imaging, and point shear wave speed (SWS) measurement. RESULTS: Pathological examination revealed 31 (33.3%) of the 93 lesions were malignant and the remaining 62 (66...
April 13, 2018: Clinical Hemorheology and Microcirculation
Zuhal Bayramoglu, Emine Caliskan, Zeynep Karakas, Deniz Tugcu, Serap Karaman, Ayper Somer, Manolya Kara, Ferhan Akıcı, Ibrahim Adaletli
OBJECTIVE: To determine the diagnostic utility of a vascularity index via superb microvascular imaging in lymph nodes of children with malignant lymphoma and acute lymphadenitis compared to normal lymph nodes. METHODS: We performed a retrospective study for multiparametric lymph node (LN) evaluation. Malignant lymphoma diagnosed via histopathological examination and lymph nodes receiving an acute lymphadenitis diagnosis based on clinical and laboratory findings constituted the study subgroups...
April 16, 2018: British Journal of Radiology
Yiqun Yang, Matthew W Urban, Robert J McGough
Shear wave calculations induced by an acoustic radiation force are very time-consuming on desktop computers, and high-performance graphics processing units (GPUs) achieve dramatic reductions in the computation time for these simulations. The acoustic radiation force is calculated using the fast near field method (FNM) and the angular spectrum approach (ASA), and then the shear waves are calculated in parallel with Green's functions on a GPU. This combination enables rapid evaluation of shear waves for push beams with different spatial samplings and for apertures with different f/#...
April 16, 2018: Physics in Medicine and Biology
Lin Wang, Cai-Feng Wan, Jing Du, Feng-Hua Li
OBJECTIVES: The purpose of this study was to evaluate the application of a new elastographic technique, acoustic radiation force impulse (ARFI) imaging, and its diagnostic performance for characterizing breast lesions. METHODS: One hundred consecutive female patients with 126 breast lesions were enrolled in our study. After routine breast ultrasound examinations, the patients underwent ARFI elasticity imaging. Virtual Touch tissue imaging (VTI) and Virtual Touch tissue quantification (Siemens Medical Solutions, Mountain View, CA) were used to qualitatively and quantitatively analyze the elasticity and hardness of tumors...
April 15, 2018: Journal of Ultrasound in Medicine: Official Journal of the American Institute of Ultrasound in Medicine
Ivana Mikolasevic, Tomislav Bokun, Tajana Filipec-Kanizaj
No abstract text is available yet for this article.
April 12, 2018: International Journal of Urology: Official Journal of the Japanese Urological Association
Xue Yang, Ning Yu, Jing Yu, Hongqiao Wang, Xiumei Li
The aim of this study was to evaluate Virtual Touch tissue quantification in assessing renal interstitial fibrosis in patients with idiopathic nephrotic syndrome. Ninety patients with idiopathic nephrotic syndrome were assigned to mild, moderate and severe groups depending on the degree of renal interstitial fibrosis on histopathologic examination of renal biopsy specimens. Thirty healthy patients were also selected as the control group. Virtual Touch tissue quantification was performed to measure the shear wave velocity of the renal parenchyma...
April 9, 2018: Ultrasound in Medicine & Biology
Caroline Ewertsen, Jonathan Carlsen, Mohammed Aftab Perveez, Henrik Schytz
Purpose: to establish reference values for ultrasound shear-wave elastography for pericranial muscles in healthy individuals (m. trapezius, m. splenius capitis, m. semispinalis capitis, m. sternocleidomastoideus and m. masseter). Also to evaluate day-to-day variations in the shear-wave speeds and evaluate the effect of the pennation of the muscle fibers, ie scanning parallel or perpendicularly to the fibers. Materials and Methods: 10 healthy individuals (5 males and 5 females) had their pericranial muscles examined with shear-wave elastography in two orthogonal planes on two different days for their dominant and non-dominant side...
January 2018: Ultrasound International Open
Jianxue Liu, Yaoren Zhang, Yonghao Ji, Qinyun Wan, Guoliang Dun
PURPOSE: The aim of this study is to discuss the value of ultrasound-based shear wave™ elastography (SWE) in diffuse thyroid disease (DTD). METHOD: Thyroid stiffness in 154 patients with DTD and 30 normal subjects was measured by SWE. The serum indicators of all subjects were detected. RESULTS: The area under the receiver operating characteristic (AUROC) curve for DTD by SWE was 0.852. The AUROCs of SWE for differentiating chronic autoimmune thyroiditis (CAT) from Graves' disease (GD) and subacute thyroiditis (SAT) were 0...
March 29, 2018: Clinical Imaging
Natalya F Naumenko
Multilayered substrates, including thin plates of LiTaO3 (LT) bonded to silicon (Si) or glass wafers either directly or via intermediate layers, were numerically investigated as potential materials for surface acoustic wave (SAW) resonators with high quality (Q)-factor required for the next generation of mobile communication systems. The propagation velocities and electromechanical coupling coefficients of shear horizontally (SH) polarized acoustic waves were estimated as functions of LT orientation and thicknesses of all layers in LT/Si, LT/SiO2 /Si, LT/glass, LT/AlN/glass and structures with several pairs of SiO2 /AlN layers between LT and the glass wafer...
March 31, 2018: Ultrasonics
Phillipp Sievers, Christopher Moß, Uwe Schröder, Diethelm Johannsmann
Whereas the study of interfaces and thin films with the quartz crystal microbalance (QCM) is well established, biofilms have proven to be a difficult subject for the QCM. The main problem is that the shear wave emanating from the resonator surface does not usually reach to the top of the sample. This problem can be solved with torsional resonators. These have a resonance frequency in the range of tens of kHz, which is much below the frequency of the thickness-shear QCMs. The depth of penetration of the shear wave is correspondingly larger...
March 22, 2018: Biosensors & Bioelectronics
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