Relative contributions of various modes of acoustic radiation force to creating mechanical stress in soft tissues

2016 ◽  
Vol 139 (4) ◽  
pp. 2027-2027
Author(s):  
Armen Sarvazyan ◽  
Lev Ostrovsky
Keyword(s):  
Mechanical Stress ◽  
Soft Tissues ◽  
Acoustic Radiation ◽  
Radiation Force ◽  
Acoustic Radiation Force

scholarly journals Acoustic radiation force-based elasticity imaging methods

2011 ◽  
Vol 1 (4) ◽  
pp. 553-564 ◽  
Author(s):  
Mark L. Palmeri ◽  
Kathryn R. Nightingale
Keyword(s):  
Mechanical Properties ◽  
Soft Tissues ◽  
Acoustic Radiation ◽  
Imaging Techniques ◽  
Radiation Force ◽  
Acoustic Radiation Force ◽  
Acoustic Properties ◽  
Elasticity Imaging Techniques ◽  
Elasticity Imaging ◽  
Imaging Methods

Conventional diagnostic ultrasound images portray differences in the acoustic properties of soft tissues, whereas ultrasound-based elasticity images portray differences in the elastic properties of soft tissues (i.e. stiffness, viscosity). The benefit of elasticity imaging lies in the fact that many soft tissues can share similar ultrasonic echogenicities, but may have different mechanical properties that can be used to clearly visualize normal anatomy and delineate pathological lesions. Acoustic radiation force-based elasticity imaging methods use acoustic radiation force to transiently deform soft tissues, and the dynamic displacement response of those tissues is measured ultrasonically and is used to estimate the tissue's mechanical properties. Both qualitative images and quantitative elasticity metrics can be reconstructed from these measured data, providing complimentary information to both diagnose and longitudinally monitor disease progression. Recently, acoustic radiation force-based elasticity imaging techniques have moved from the laboratory to the clinical setting, where clinicians are beginning to characterize tissue stiffness as a diagnostic metric, and commercial implementations of radiation force-based ultrasonic elasticity imaging are beginning to appear on the commercial market. This article provides an overview of acoustic radiation force-based elasticity imaging, including a review of the relevant soft tissue material properties, a review of radiation force-based methods that have been proposed for elasticity imaging, and a discussion of current research and commercial realizations of radiation force based-elasticity imaging technologies.

O-124 Contact-free oocyte denudation in a chip-scale ultrasonic microfluidic device

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
A Mokhtare ◽  
P Xie ◽  
B Davaji ◽  
A Abbaspourrad ◽  
Z Rosenwaks ◽  
...  
Keyword(s):  
Mechanical Stress ◽  
Embryo Development ◽  
Microfluidic Device ◽  
Acoustic Waves ◽  
Acoustic Radiation ◽  
Gas Permeability ◽  
Surface Acoustic Waves ◽  
Radiation Force ◽  
Ultrasonic Waves ◽  
Acoustic Radiation Force

Abstract Study question To design and test an automated microfluidic device to revolutionize the cumulus-oocyte-complex (COC) denudation procedure for intracytoplasmic sperm injection (ICSI) using murine oocytes. Summary answer Oocyte exposure to temperature variation, mechanical stress, and prolonged chemical treatment during denudation was mitigated using our microfluidic device based on surface acoustic waves (SAWs). What is known already COC denudation is a prerequisite for many ART procedures such as ICSI. However, this procedure is based on manual pipetting (MP), which lacks standardization and requires experienced embryologists to perform. Inadequate MP may damage oocytes through prolonged enzymatic treatment or high fluidic stresses and may jeopardize gamete competence. The use of microfluidic devices based on porous membranes or microchannels has been adopted by many laboratories for sperm selection. Of these, microchannel devices may also be adapted for denudation with minimal mechanical stress in a controlled microenvironment. However, oocyte manipulation and extraction have proven difficult to achieve. Study design, size, duration We developed a novel ultrasonic microfluidic device based on a microwell design manufactured with Polydimethylsiloxane (PDMS). The SAWs were generated by 4 interdigitated transducers (IDTs) arranged in an orthogonally symmetric pattern. A non-toxic dosage of ultrasonic waves, similar to those used in gynecology and obstetrics, was applied. COCs were denuded by induced acoustic streaming and acoustic radiation force. Denudation rate, embryo development, and pregnancy outcomes were assessed and compared to control oocytes denuded by MP. Participants/materials, setting, methods For each run, up to 10 individual COCs from super-ovulated B6D2F1 mice were loaded into the microwell alongside diluted hyaluronidase (20 IU/ml) and denuded by 80 or 200 MHz SAWs. Denuded oocytes were fertilized by piezo-actuated ICSI using spermatozoa from the same strain. Pre-implantation embryo development was assessed in a time-lapse incubator for up to 96 h. High-quality blastocysts were transferred to 2.5-dpc pseudo-pregnant CD-1 surrogates. Pregnancy and offspring health were observed. Main results and the role of chance Using alternating frequency sweep in a pulse-repetition mode, we swirled the fluid inside the microwell consistently and tumbled COCs inside the microwell to expose them to acoustic steaming-induced drag forces and acoustic radiation force. Using a high-speed camera and particle-tracking technique, we observed that the drag force generated by the SAWs fulfilled the denudation mechanism. Additionally, due to the small attenuation coefficient in water, thermal absorption heating remains minuscule, preventing any thermal-induced damage. Our device significantly reduced the time and labor of the denudation process. It also yielded proper denudation quality without oocyte loss. To ensure that SAWs do not damage oocytes, 40 oocytes denuded by 80 MHz SAWs, 25 oocytes denuded by 200 MHz SAWs, and 30 oocytes denuded by MP were inseminated by piezo-actuated ICSI. The 80-MHz, 200-MHz, and MP groups yielded comparable post-ICSI survival (82.5% vs. 84.0% vs. 83.3%, respectively), fertilization (80.0% vs. 80.0% vs. 83.3%,respectively), and blastulation rates (72.5% vs. 82.0% vs. 66.7%, respectively). Embryo morphokinetics were also not impacted. After transferring all blastocysts into recipient mice, 8 live births were achieved from the 80-MHz group, while 5 were achieved from the 200-MHz group. Limitations, reasons for caution Although PDMS is a popular material due to its high optical transparency and biocompatibility, adverse effects due to gas permeability and small-molecule adsorption cannot be excluded. Large-scale mouse embryo assays should be performed to assess the teratogenicity of PDMS. Operation parameters must be optimized for human COCs in clinical application. Wider implications of the findings Adopting widely used ultrasound techniques with emerging SAW technology is a major step toward advancing and standardizing oocyte denudation—a laborious yet delicate procedure. We predict it will be further integrated with AI and miniaturized robotics, modules specialized in gamete assessment, ICSI, and embryo evaluation in the near future. Trial registration number ‘not applicable’

Modeling Dynamic Responses of Viscoelastic Heterogeneous Soft Tissues to Step Acoustic Radiation Force

2013 ◽  
Author(s):  
Xiaodong Zhao ◽  
Assimina A. Pelegri
Keyword(s):  
Soft Tissue ◽  
Dynamic Response ◽  
Soft Tissues ◽  
Acoustic Radiation ◽  
Three Dimensional ◽  
Radiation Force ◽  
Element Model ◽  
Acoustic Radiation Force ◽  
Degree Of Freedom ◽  
Dynamic Responses

The responses of soft tissue under acoustic radiation force excitations are used to image tissue mechanical properties for soft tissue discrimination and detection of breast tumors. The soft tissue viscoelasticy has been interrogated by step acoustic radiation force excitations. The corresponding induced time-dependent creep displacement is used to reconstruct soft tissue viscoelasticity or to estimate viscosity and elasticity contrast of the inclusion to background. The acoustic radiation force is highly localized in a small excitation region; and, one degree-of-freedom and homogenous assumptions are generally made to the analysis. However, these simplifying assumptions limit the accuracy of these methods. In this paper, a finite element model was built to demonstrate the effect of the dynamic response of viscoelastic heterogeneous soft tissue to step acoustic radiation force. Factors affecting the dynamic response of soft tissue were first investigated with the homogenous model, and the corresponding estimation quality based on the one degree-of-freedom model was evaluated. Then, the dynamic response of soft tissue with inclusion and different elasticity and viscocity for the tissue and the inclusion was studied. The results suggest that in order to improve the estimate of soft tissue viscoelasticity the heterogenenous nature of the tissue and its three dimensional geometry should be accounted in the model.

scholarly journals The safety and feasibility of diagnostic acoustic radiation force impulse elastography used for eyes. A preliminary in vivo study

2017 ◽  
Vol 19 (2) ◽  
pp. 185 ◽  
Author(s):  
Li Zha ◽  
Ke Qi Chen ◽  
Xiao Zhi Zheng ◽  
Jing Wu
Keyword(s):  
Soft Tissues ◽  
Acoustic Radiation ◽  
Radiation Force ◽  
Acoustic Radiation Force ◽  
Acoustic Radiation Force Impulse ◽  
Expression Level ◽  
Light Reflex ◽  
Sd Rats ◽  
Tnf Α ◽  
Arfi Elastography

Aims: To assess the safety and feasibility of acoustic radiation force impulse (ARFI) elastography in the eyes of rats. Material and methods: One hundred and twenty-six SD rats were divided into 7 groups. Group 1 was the control group and Group 2 to Group 7 were investigated by ARFI elastography using increased powers of 5%, 10%, 20%, 50%, and 100% and repetitions of 5 or 10. The changes of ocular architecture structures and functions were examined by phthalmoscopic, histopathologic, and light reflex examination, and the expression level of IL-6, IL-8, and TNF-α was determined in days 1, 3, and 7 after ARFI elastography, respectively.Results: A satisfactory ARFI elastography was obtained in all SD rats. The shear wave velocity (SWV) values of soft tissues behind the eyeball were significantly greater than those of the eyes (1.89±0.95 vs. 0.84±0.36 m/s, p<0.05). The SWV values of eyes and the soft tissues behind the eyeball did not differ among any groups at any time-point (p>0.05). The SD rats of each group showed good light perception, pupillary light reflex, and avoidance reaction induced by the sudden bright light from the dark environment at any time. In each group, ocular architecture structures were well preserved, and with a normal expression level of IL-6, IL-8, and TNF-α (p>0.05).Conclusions: Diagnostic ARFI elastography is a safe and feasible ultrasonic imaging mode and may potentially be applied for human eyes in its present form.

Rationale Abklärung von Lebererkrankungen

2017 ◽  
Vol 74 (3) ◽  
pp. 79-86
Author(s):  
Leona von Köckritz ◽  
Andrea De Gottardi
Keyword(s):  
Acoustic Radiation ◽  
Radiation Force ◽  
Acoustic Radiation Force ◽  
Acoustic Radiation Force Impulse ◽  
Alkalische Phosphatase ◽  
Gamma Glutamyltransferase ◽  
Alpha 1 Antitrypsin

Zusammenfassung. Im klinischen Alltag werden häufig erhöhte Leberwerte beobachtet. In der Regel erfordern sie weitere Abklärungen bezüglich der möglichen Ätiologie und des Schweregrad einer akuten oder chronischen Lebererkrankung. Die Abklärung sollte dabei neben einer gezielten Anamnese und sorgfältigen klinischen Untersuchung, auch die Bestimmung von laborchemischen Markern für Cholestase und Leberfunktionsstörungen (wie Alkalische Phosphatase, gamma-Glutamyltransferase, Bilirubin, Albumin und Gerinnungsfaktoren) umfassen. Die Bestimmung weiterer Parameter wie Ferritin und Transferrinsättigung, Autoimmunantikörper, Virusserologien, alpha-1 Antitrypsin und Coerulolasmin können weitere Hinweise für die kausalen Zusammenhänge der Leberfunktionsstörung liefern. Bei Patienten mit Lebererkrankungen ist eine sonografische Beurteilung der Leber obligat. Ergänzend zur Sonografie werden heute weitere nicht-invasive Methoden wie Fibroscan, Acoustic Radiation Force Impulse Elastometrie und Magnet-Resonanz-Elastografie zur Beurteilung der Leberfibrose eingesetzt. In ausgewählten Fällen ist eine Leberbiopsie notwendig, um den Grad der Fibrose und die Ätiologie der Lebererkrankung zu eruieren. Mithilfe eines Fallbeispiels, diskutieren die Autoren im Folgenden die rationale Anwendung diagnostischer Tests und deren korrekte Interpretation und schlagen eine Orientierungshilfe zur rationalen Abklärung von Patienten mit Lebererkrankungen vor.

Neue Horizonte bei der Lebersonographie

Praxis ◽  
2012 ◽  
Vol 101 (18) ◽  
pp. 1161-1166
Author(s):  
Hagara ◽  
Schwarzenbach ◽  
Cerny
Keyword(s):  
Acoustic Radiation ◽  
Radiation Force ◽  
Acoustic Radiation Force ◽  
Acoustic Radiation Force Impulse

Dank technologischer Verbesserungen und einer immer besser werdenden klinischen Evidenzlage wird der diagnostische Ultraschall im Vergleich zu den Röntgen- und Magnetresonanzverfahren vermehrt eingesetzt. Dies nicht nur aus Kostengründen, sondern auch um der Zunahme der Strahlenbelastung der Bevölkerung durch diagnostische ionisierende Strahlen entgegenzuwirken. In der folgenden Übersichtsarbeit versuchen die Autoren die neuesten Entwicklungen im Bereich des Leberultraschalls vorzustellen. Bemerkenswert sind Verfahren, die eine dynamische Untersuchung der Leberdurchblutung mittels Kontrastmittelultraschall (Schwefelhexafluorid SonoVue®) und damit Verbesserungen bei der Charakterisierung von fokalen Leberläsionen wie Metastasen extrahepatischer Tumoren, Regeneratsknoten bei Leberzirrhose, fokaler nodulärer Hyperplasie, hepatozellu-lärem Karzinom, Leberhämangiom, Leberadenom sowie fokaler Mehr- oder Minderverfettung ermöglichen. Ebenfalls wichtig sind Techniken, die eine Bestimmung der Gewebekonsistenz mittels transienter Elastographie (Fibroscan), ARFI (Acoustic Radiation Force Impulse) oder Echtzeit-Gewebe-Elastographie erlauben. Die Quantifizierung des Steatosegrads ist für Diagnose und Verlaufsbeurteilung von Leberpathologien unabdingbar.

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