2026-09-19T04:59:23Zhttps://dspace.mit.edu/server/oai/request

oai:dspace.mit.edu:1721.1/1137492023-06-28T16:52:14Zcom_1721.1_7582com_1721.1_7581col_1721.1_131023

Brian W. Anthony. Yang, Heng(Mechanical engineer) Massachusetts Institute of Technology Massachusetts Institute of Technology. Department of Mechanical Engineering. Massachusetts Institute of Technology. Department of Mechanical Engineering 2018-02-16T20:04:16Z 2018-02-16T20:04:16Z 2017 2017 http://hdl.handle.net/1721.1/113749 1021853994 Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017. Cataloged from PDF version of thesis. Includes bibliographical references (pages 105-107). Ultrasound shear wave elastography (SWE) imaging is gaining wide acceptance in clinical practice as both a non-invasive and quantitative diagnostic modality. Most commercial SWE systems generate shear waves using acoustic radiation force (ARF), which requires complex hardware and is therefore only available on high-end and premium systems. External mechanical vibration (EMV) is an alternative to induce shear waves without expensive electronics, which potentially enables low-cost systems to provide SWE for point of care and low resource settings. In this thesis, an EMV concept of sinusoidally and synchronically vibrating two ball-shaped end-effectors to induce shear waves for real time SWE imaging was simulated, prototyped and tested. Finite element method (FEM) simulation and analysis shows the sinusoidal vibration generates shear waves that are constructive across the center plane of the two balls. By tracking the local displacement profiles at different depths of the center plane, shear wave speeds can be accurately estimated for different tissue stiffness. A mechatronic device using a voice coil actuator (VCA) to realize the EMV concept was prototyped. The mechanical vibrator was mounted on a commercial ultrasound probe and the vibration was synchronized with commercial ultrasound platform to induce shear waves as replacement of ARF. The generated shear waves were imaged by commercial ultrasonic systems to calculate shear wave speed and estimate tissue elasticity. Experimental data on liver phantoms under various vibration schemes demonstrated the capability of using this EMV device to conduct real-time SWE imaging that is comparable to ARF based systems. by Heng Yang. S.M. 107 pages eng Massachusetts Institute of Technology MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission. http://dspace.mit.edu/handle/1721.1/7582 Mechanical Engineering. Ultrasound shear wave elastography imaging with external mechanical vibration Ultrasound SWE imaging with EMV Thesis application/pdf false Publication unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="961a86ff-cab5-4bb8-afc1-663515038c5e"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Language>eng</Language> <Title>Ultrasound shear wave elastography imaging with external mechanical vibration</Title> <Subtitle>Ultrasound SWE imaging with EMV</Subtitle> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>2017</PublicationDate> <Authors> <Author> <DisplayName>Yang, Heng(Mechanical engineer) Massachusetts Institute of Technology</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>http://dspace.mit.edu/handle/1721.1/7582</License> <Keyword>Mechanical Engineering.</Keyword> <Abstract>Ultrasound shear wave elastography (SWE) imaging is gaining wide acceptance in clinical practice as both a non-invasive and quantitative diagnostic modality. Most commercial SWE systems generate shear waves using acoustic radiation force (ARF), which requires complex hardware and is therefore only available on high-end and premium systems. External mechanical vibration (EMV) is an alternative to induce shear waves without expensive electronics, which potentially enables low-cost systems to provide SWE for point of care and low resource settings. In this thesis, an EMV concept of sinusoidally and synchronically vibrating two ball-shaped end-effectors to induce shear waves for real time SWE imaging was simulated, prototyped and tested. Finite element method (FEM) simulation and analysis shows the sinusoidal vibration generates shear waves that are constructive across the center plane of the two balls. By tracking the local displacement profiles at different depths of the center plane, shear wave speeds can be accurately estimated for different tissue stiffness. A mechatronic device using a voice coil actuator (VCA) to realize the EMV concept was prototyped. The mechanical vibrator was mounted on a commercial ultrasound probe and the vibration was synchronized with commercial ultrasound platform to induce shear waves as replacement of ARF. The generated shear waves were imaged by commercial ultrasonic systems to calculate shear wave speed and estimate tissue elasticity. Experimental data on liver phantoms under various vibration schemes demonstrated the capability of using this EMV device to conduct real-time SWE imaging that is comparable to ARF based systems.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>