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Dissertations / Theses on the topic 'Shear wave imaging'

Author: Grafiati

Published: 4 June 2021

Last updated: 1 June 2024

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1

Nordenfur, Tim. "Comparison of Pushing Sequences for Shear Wave Elastography." Thesis, KTH, Skolan för teknik och hälsa (STH), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-124123.

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Shear wave elastography is a medical imaging modality in which tissue elasticity is estimated by measuring the speed of ultrasound-induced shear waves. This study aimed to implement four shear wave generating pushes and compare their performance according to chosen metrics. The focused push, unfocused push, unfocused comb push and line push were implemented on a Verasonics ultrasound system and tested on a polyvinyl alcohol phantom. Shear wave propagation was imaged using angle-compounded ultrafast imaging. Axial particle velocities were estimated using a 2D autocorrelator and then cross-corre

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2

Yang, Heng S. M. Massachusetts Institute of Technology. "Ultrasound shear wave elastography imaging with external mechanical vibration." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/113749.

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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 105-107).<br>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 indu

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3

Budelli, Eliana. "Development of ultrasonic shear wave elastography for rheological properties assessment." Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCC130.

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L’élastographie par ondes de cisaillement consiste essentiellement en deux étapes: d'abord, une onde de cisaillement est générée en appliquant soigneusement une source contrôlée externe (par exemple actionneur mécanique ou force de rayonnement ultrasonore); Alors les déplacements induits sont imagés et l'élasticité tissulaire est déduite de la propagation d'onde de cisaillement mesurée. Cependant, avec les techniques d'élastographie actuellement disponibles, l'estimation quantitative correcte de la viscosité n'est pas possible. Dans ce contexte, le but principal de cette thèse est double: d'ab

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4

Almayahi, Ali Z. "SHEAR-WAVE IMAGING AND BIREFRINGENCE IN A COMPLEX NEAR-SURFACE GEOLOGICAL ENVIRONMENT." UKnowledge, 2013. http://uknowledge.uky.edu/ees_etds/12.

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Multiple geophysical and geological data sets were compiled, reprocessed, and interpreted using state-of-the-art signal processing and modeling algorithms to characterize the complex post-Paleozoic geology that overlies the southwestern projection of the Fluorspar Area Fault Complex (FAFC) in western Kentucky. Specific data included 21.5 km of SH-wave seismic reflection, 1.5 km of P-wave seismic reflection, 2 km of electrical resistivity, vertical seismic profiles, Vp and Vs sonic-suspension logs, and 930 lithologic borehole logs. The resultant model indicates three general northeast–southwest

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Ge, Weirong. "The Improvement of Shear-wave Elastography Imaging in Prediction of Preterm Birth." Thesis, The University of Sydney, 2022. https://hdl.handle.net/2123/29510.

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Complications from preterm birth are one of the leading causes of perinatal mortality and morbidity worldwide. These complications lead to short-term and long-term consequences that are a huge emotional burden to families and a financial burden to the healthcare system. The risk of preterm birth is predicted with the standard methods of assessing obstetric history, measuring cervical length, and other less common practices such as measuring fetal fibronectin concentration. Despite research efforts in this field, the accuracy of diagnosis of preterm birth is not at a satisfactory level. Shear-

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6

Correia, Mafalda Filipa Rodrigues. "From 2D to 3D cardiovascular ultrafast ultrasound imaging : new insights in shear wave elastography and blood flow imaging." Thesis, Sorbonne Paris Cité, 2016. http://www.theses.fr/2016USPCC158.

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Ces travaux de thèse portent sur le développement de nouvelles modalités d’imagerie cardiovasculaire basé sur l’utilisation de l'imagerie ultrarapide 2D et 3D. Les modalités d’imagerie développées dans cette thèse appartiennent au domaine de de l’élastographie par onde de cisaillement et de l'imagerie Doppler des flux sanguins.Dans un premier temps, la technique de l’élastographie par onde de cisaillement du myocarde a été développée pour les applications cliniques. Une approche d'imagerie non-linéaire a été utilisée pour améliorer l’estimation de vitesse des ondes de cisaillement (ou la rigid

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7

Skerl, Katrin. "Standardisation and quality assurance of 2D ultrasound Shear Wave Elastography imaging in breast tissue." Thesis, University of Dundee, 2016. https://discovery.dundee.ac.uk/en/studentTheses/5ee2b3ed-89aa-4874-830a-ec9be233aae4.

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Breast cancer is the most common cancer in women worldwide. In 2009, a novel imaging modality called Shear Wave Elastography (SWE), an ultrasound technique visualising the elasticity of tissue, was introduced to the field of clinical breast imaging. Because malignant tissues are generally stiffer than benign tissues, SWE supports the differentiation of benign / malignant solid breast lesions. However, no standard has yet been defined for the application and the evaluation of results. Furthermore, image evaluation has to be carried out directly from the ultrasound system, complicating long-term

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8

Chan, Cho-cheong, and 陳楚莊. "Magnetic resonance elastography: neuronal andmuscular studies, and a novel acoustic shear wave generator." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B38643868.

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9

Chan, Cho-cheong. "Magnetic resonance elastography neuronal and muscular studies, and a novel acoustic shear wave generator /." Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/hkuto/record/B38643868.

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10

Ormachea, Quispe Juvenal. "Evaluation of shear wave speed measurements using crawling waves sonoelastography and single tracking location acoustic radiation force impulse imaging." Master's thesis, Pontificia Universidad Católica del Perú, 2015. http://tesis.pucp.edu.pe/repositorio/handle/123456789/6195.

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Many pathological conditions are closely related with an increase in tissue sti ness. For many years, experts performed manual palpation in order to measure elasticity changes, however, this method can only be applied on superficial areas of the human body and provides crude sti ness estimation. Elastography is a technique that attempts to characterize the elastic properties of tissue in order to provide additional and useful information for clinical diagnosis. For more than twenty years, di erent research groups have developed various elastography modalities with a strong interest for quantit

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11

Yousef, Baban Mustafa. "Analysis of shear-wave response to fractures : a full waveform study of microseismic fracture imaging." Thesis, University of Leeds, 2016. http://etheses.whiterose.ac.uk/16132/.

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Naturally fractured reservoirs are playing an important role in exploration geophysics. As fractures can control the permeability and pore pressure of the reservoir, it is crucial to study the fracture characterisation. The thesis is mainly including the estimated seismic anisotropy from shear-wave splitting (SWS) observations and the study of the S-wave scattering characteristics of fractured media as well. A suite of synthetic fractured media with a broad range of fracture parameters is generated. The range of fracture parameters was chosen based on the numerical simulation and also where th

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12

Maksuti, Elira. "Imaging and modeling the cardiovascular system." Doctoral thesis, KTH, Medicinsk bildteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-196538.

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Understanding cardiac pumping function is crucial to guiding diagnosis, predicting outcomes of interventions, and designing medical devices that interact with the cardiovascular system. Computer simulations of hemodynamics can show how the complex cardiovascular system is influenced by changes in single or multiple parameters and can be used to test clinical hypotheses. In addition, methods for the quantification of important markers such as elevated arterial stiffness would help reduce the morbidity and mortality related to cardiovascular disease. The general aim of this thesis work was to i

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13

Le, blay Heiva. "Use of shear wave imaging to assess the mechanical and fracture behaviors of tough model gels." Electronic Thesis or Diss., Université Paris sciences et lettres, 2021. http://www.theses.fr/2021UPSLS096.

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Un hydrogel est un matériau mou, largement gonflé d’eau, rendu élastique via un réseau de chaînes de polymère. Un gel est intrinsèquement fragile. On peut remédier à cette fragilité grâce à l’ajout de liaisons sacrificielles dynamiques. L’ingénierie macromoléculaire a permis au XXIème siècle de formuler des gels à destination de la biologie afin de proposer des matériaux de synthèse tout en remédiant aux problèmes de biocompatibilité, à la compatibilité des interfaces tissu/matériau et des propriétés mécaniques dont le corps a besoin. Pourtant, la fracture de ces matériaux hautement déformable

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14

BATTAGLIA, ENZO. "Seismic reflection imaging of near surface structures using the Common Reflection Surface (CRS) Stack Method." Doctoral thesis, Università degli Studi di Cagliari, 2014. http://hdl.handle.net/11584/266406.

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This PhD thesis aims to evaluate whether the Common-Refl ection-Surface (CRS) stack method can be considered as a more cost efficient processing alternative to the conventionally used Common Midpoint (CMP) stack method for processing of shallow and ultrashallow reflection data. The CRS stack is a seismic imaging method established for oil and gas exploration that is similar in concept to the conventional CMP stack method. Unlike the CMP stack, the CRS stack process is not confined to single CMP gathers (offset direction), but also includes neighbouring CMPs (midpoint direction) into the s

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15

Schulze, Judith [Verfasser]. "Ermittlung von Normwerten der Shear Wave Elastographie mit dem Acoustic Radiation Force Imaging Verfahren an der Milz / Judith Schulze." Ulm : Universität Ulm, 2018. http://d-nb.info/1150781211/34.

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16

Payne, Catherine. "Clinical applications of shear wave elastography to achilles tendon imaging and the monitoring of a rehabilitation protocol for achilles tendinopathy." Thesis, University of Brighton, 2018. https://research.brighton.ac.uk/en/studentTheses/7e9deb5d-b2af-4f85-90b7-d7613811035c.

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17

Rosandich, Brooks. "Extension of a Quaternary-Active Shear Zone across the Reelfoot Fault Stepover Arm: Evidence from P- and SH-wave Seismic Reflection Imaging." UKnowledge, 2019. https://uknowledge.uky.edu/ees_etds/79.

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Many seismic hazard source parameters such as slip rate, total displacement, strain accommodation, geographic fault location, etc. are poorly constrained in the New Madrid seismic zone (NMSZ). This is in large part due to the masking effect of the thick Mississippi embayment sediment package on seismogenic structures and features. Consequently, much of the subsurface geologic characterization needed for understanding seismic hazard sources requires geophysical imaging. Recent seismic reflection surveys 12 km NE of the Reelfoot Fault stepover arm of the NMSZ have suggested a northeast-oriented

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18

Cassinotto, Christophe. "Diagnostic et évaluation de la gravité des maladies chroniques du foie : impact de l’elastographie par ondes de cisaillement « supersonic shear imaging »." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0231/document.

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Les maladies chroniques du foie constituent un problème majeur de santé publique. L’évaluation précise du degré de fibrose hépatique apporte au clinicien une estimation du pronostic dès la prise en charge initiale de ces patients, mais permet également la réalisation d’une surveillance évolutive, et intervient dans la décision et le choix d’un traitement. L’évaluation noninvasive de la fibrose hépatique par élastographie a permis de révolutionner la prise en charge des malades atteints d’une maladie chronique du foie. L’objectif de notre travail est d’évaluer les performances diagnostiques d’u

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19

Ye, Wenfeng. "Numerical methods for the simulation of shear wave propagation in nearly incompressible medium - Application in elastography." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEI046.

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L'élastographie transitoire est une technologie médicale de caractérisation qui permet d'estimer la rigidité des tissus mous biologiques. En visualisant la propagation de l'onde de cisaillement dans le tissu, on peut déduire le module de cisaillement µ. Au cours de la dernière décennie, cette technique a été utilisée avec succès pour étudier diverses pathologie, en particulier la fibrose, le cancer. Cependant, de nombreux facteurs, comme par exemple, la réflexion des ondes, les conditions aux limites et la précontrainte perturbent les mesures en élastographie, la qualité de la caractérisation

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20

Bessière, Francis. "Amélioration des techniques d’ablation pour le traitement des arythmies cardiaques : nouvelles modalités diagnostiques et thérapeutiques par ultrasons." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE1225/document.

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A la croisée des chemins entre médecine et physique des ultrasons, ce travail de thèse s’est intéressé à l’apport de solutions diagnostiques et de thérapeutiques novatrices dans le domaine de l’électrophysiologie cardiaque. Un système capable de délivrer des ultrasons focalisés dans le cœur par voie transoesophagienne sous guidage par ultrasons a été développé et testé in vivo chez 6 porcs. Les tirs HIFU ont été délivrés sur les oreillettes et les ventricules. Lors de l'autopsie, une analyse visuelle a démontré la présence de lésions thermiques dans les zones ciblées chez 3 animaux. Ces lésion

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21

Ford, Matthew R. "Development and Application of Optical Coherence Elastography for Corneal Biomechanics." Case Western Reserve University School of Graduate Studies / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=case1436545044.

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22

Widman, Erik. "Ultrasonic Methods for Quantitative Carotid Plaque Characterization." Doctoral thesis, KTH, Medicinsk bildteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-192339.

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Cardiovascular diseases are the leading causes of death worldwide and improved diagnostic methods are needed for early intervention and to select the most suitable treatment for patients. Currently, carotid artery plaque vulnerability is typically determined by visually assessing ultrasound B-mode images, which is influenced by user-subjectivity. Since plaque vulnerability is correlated to the mechanical properties of the plaque, quantitative techniques are needed to estimate plaque stiffness as a surrogate for plaque vulnerability, which would reduce subjectivity during plaque assessment. The

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23

Bessière, Francis. "Amélioration des techniques d’ablation pour le traitement des arythmies cardiaques : nouvelles modalités diagnostiques et thérapeutiques par ultrasons." Electronic Thesis or Diss., Lyon, 2019. http://www.theses.fr/2019LYSE1225.

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A la croisée des chemins entre médecine et physique des ultrasons, ce travail de thèse s’est intéressé à l’apport de solutions diagnostiques et de thérapeutiques novatrices dans le domaine de l’électrophysiologie cardiaque. Un système capable de délivrer des ultrasons focalisés dans le cœur par voie transoesophagienne sous guidage par ultrasons a été développé et testé in vivo chez 6 porcs. Les tirs HIFU ont été délivrés sur les oreillettes et les ventricules. Lors de l'autopsie, une analyse visuelle a démontré la présence de lésions thermiques dans les zones ciblées chez 3 animaux. Ces lésion

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24

Zemzemi, Chadi. "Élastographie par retournement temporel : mesure des propriétés mécaniques des tissus biologiques par réseau de sources d’onde de cisaillement." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1217/document.

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Le travail mené dans cette thèse s’inscrit dans la continuité des recherches sur l’élastographie par onde de cisaillement. Après un rappel bibliographique, la présentation d’une étude expérimentale montre que la résolution en élastographie par ultrasons est du même ordre de grandeur que la résolution en échographie et que sa limite dépasse la longueur d’onde de cisaillement. L’originalité de ce travail repose sur l’utilisation d’un réseau de sources mécaniques pour la génération et le contrôle des ondes de cisaillement. Un miroir à retournement temporel de six vibreurs est d’abord mis en place

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25

Wadas, Sonja Halina [Verfasser], Charlotte M. [Akademischer Betreuer] Krawczyk, Charlotte M. [Gutachter] Krawczyk, Ulrich [Gutachter] Polom, Frank [Gutachter] Börner, and Torsten [Gutachter] Dahm. "High-resolution shear wave reflection seismics and borehole seismics as tools for the imaging and the characterization of near-surface subrosion structures / Sonja Halina Wadas ; Gutachter: Charlotte M. Krawczyk, Ulrich Polom, Frank Börner, Torsten Dahm ; Betreuer: Charlotte M. Krawczyk." Berlin : Technische Universität Berlin, 2018. http://d-nb.info/1164076388/34.

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26

Zemzemi, Chadi. "Élastographie par retournement temporel : mesure des propriétés mécaniques des tissus biologiques par réseau de sources d’onde de cisaillement." Electronic Thesis or Diss., Lyon, 2018. http://www.theses.fr/2018LYSE1217.

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Le travail mené dans cette thèse s’inscrit dans la continuité des recherches sur l’élastographie par onde de cisaillement. Après un rappel bibliographique, la présentation d’une étude expérimentale montre que la résolution en élastographie par ultrasons est du même ordre de grandeur que la résolution en échographie et que sa limite dépasse la longueur d’onde de cisaillement. L’originalité de ce travail repose sur l’utilisation d’un réseau de sources mécaniques pour la génération et le contrôle des ondes de cisaillement. Un miroir à retournement temporel de six vibreurs est d’abord mis en place

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27

Touboul, David. "Apport de l’élastographie par imagerie des ondes de cisaillement pour l’évaluation de la photo-polymerisation du collagène cornéen." Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0051/document.

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Le cross-linking du collagène cornéen (CXL) est une cornéoplastie mini-invasive reposant surun concept biomécanique difficile à objectiver physiquement et dont les preuves del’efficacité thérapeutique sont d’interprétation complexe. Les principes, les nuances et lesrésultats du CXL sont colligés dans cette thèse afin de valider l’intérêt du modèleexpérimental choisi pour tester la pertinence de notre travail de recherche sur l’élastographiecornéenne par ondes de cisaillement.Notre cheminement expérimental a abouti au choix du modèle de CXL trans-épithélial (TCXL)assisté par iontophorèse (I-CXL

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28

Goudot, Guillaume. "Applications innovantes des ultrasons en pathologie vasculaire : utilisation de l'imagerie ultrarapide dans l'analyse de la rigidité artérielle et des ultrasons pulsés en thérapie Arterial stiffening assessed by ultrafast ultrasound imaging gives new insight into arterial phenotype of vascular Ehlers–Danlos mouse models Aortic wall elastic properties in case of bicuspid aortic valve Segmental aortic stiffness in bicuspid aortic valve patients compared to first-degree relatives Wall shear stress measurement by ultrafast vector flow imaging for atherosclerotic carotid stenosis Pulsed cavitational therapy using high-frequency ultrasound for the treatment of deep vein thrombosis in an in vitro model of human blood clot." Thesis, Sorbonne Paris Cité, 2018. https://wo.app.u-paris.fr/cgi-bin/WebObjects/TheseWeb.woa/wa/show?t=2215&f=13951.

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Balleyguier, Corinne. "Elastographie-IRM pour le diagnostic et la caractérisation des lésions du sein." Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-00824882.

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L'élastographie-IRM du sein (MRE) est une technique d'imagerie fonctionnelle non invasive utilisant les propriétés visco-élastiques des tissus et qui permet comme en élastographie-échographie d'évaluer la rigidité d'une lésion. Il est également possible, à la différence de l'élastographie-échographie, d'évaluer le degré de viscosité d'une lésion, et ainsi grâce à la combinaison élasticité/viscosité, comparée à l'analyse des paramètres IRM classiques comme la morphologie ou la cinétique de rehaussement, d'améliorer la caractérisation lésionnelle. Très peu d'études en élastographie-IRM du sein o

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Kummer, Joseph W. "Signal processing methods to quantify scattering of angle-beam shear waves from through-holes in plates." Thesis, Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54411.

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The objective of this thesis is to present analysis techniques that quantify the scattering of angle-beam ultrasonic waves from through-holes in plates. This topic is of interest because increased understanding of the scattering of ultrasonic waves by a defect is important for the development of many nondestructive evaluation (NDE) applications. Angle-beam techniques are commonly used in industry to detect and characterize defects, and many structures of concern have plate-like components. Scattering from through-holes is particularly important because cracks tend to form around fastener holes

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SOUSA, Welington Barbosa de. "Simulação numérica de propagação da onda cisalhante em rochas sedimentares a partir de imagens microtomográficas de Raios X." Universidade Federal de Campina Grande, 2017. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/1265.

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Submitted by Marcos Wanderley (marcos.wanderley@ufcg.edu.br) on 2018-07-26T20:07:51Z No. of bitstreams: 1 WELINGTON BARBOSA DE SOUSA - DISSERTAÇÃO(PPGEPM) 2017.pdf: 2079159 bytes, checksum: c91660187b1af81f4801a2dccb0a5b76 (MD5)<br>Made available in DSpace on 2018-07-26T20:07:51Z (GMT). No. of bitstreams: 1 WELINGTON BARBOSA DE SOUSA - DISSERTAÇÃO(PPGEPM) 2017.pdf: 2079159 bytes, checksum: c91660187b1af81f4801a2dccb0a5b76 (MD5) Previous issue date: 2017-05-26<br>O conhecimento das propriedades petrofísicas é de grande importância para melhor entender o comportamento físico das rochas, especi

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Arnal, Bastien. "Elastographie pour le suivi des thérapies par ultrasons focalisés et nouveau concept de cavité à retournement temporel pour l'histotripsie." Phd thesis, Université Paris-Diderot - Paris VII, 2013. http://pastel.archives-ouvertes.fr/pastel-00786523.

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L'émission d'ultrasons focalisés à forte puissance peut être utilisée pour réaliser l'ablation non-invasive de zones pathogènes, de type cancéreuses par exemple. On distingue deux régimes d'ablations : ablation thermique appelée HIFU (" High Intensity Focused Ultrasound ") et ablation mécanique appelée histotripsie utilisant des ondes de chocs focalisées. Au cours de ma thèse, nous avons développé des méthodes de suivi ultrasonore en temps réel à partir d'une technique d'élastographie quantitative (Supersonic Shear wave Imaging). Nous montrerons que des mesures précises des changements d'élast

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Papazoglou, Sebastian. "Elucidation of isotropic and anisotropic shear elasticity of in vivo soft tissue using planar magnetic resonance elastography." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2010. http://dx.doi.org/10.18452/16136.

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Die Magnetresonanzelastographie (MRE) stellt ein nichtinvasives Verfahren dar, welches die Bestimmung der in vivo Scherelastizität weicher Gewebe ermöglicht. Im Rahmen diese Arbeit wurden Methoden zur Bestimmung isotroper und anisotroper Scherelastizitäten anhand von MRE Wellenbildern entwickelt und evaluiert. Alle in dieser Arbeit vorgestellten Methoden basieren auf planarer MRE, d.h. auf der Aufnahme einer einzelnen Auslenkungskomponente innerhalb der Bildschicht. Dadurch wird die MRE erheblich beschleunigt. Allerdings stellen sich dadurch auch besondere Anforderungen an die Datenauswertun

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34

Ho, Nien-Ching, and 何念青. "Improving Resolution of Shear Wave Elasticity Imaging –Near Field Imaging and Shear Wave Computed Tomography." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/52326252601773460374.

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碩士<br>國立臺灣大學<br>生醫電子與資訊學研究所<br>103<br>High frequency ultrasound imaging, which provides higher spatial resolution and better sensitivity for detecting shear wave displacement, is suitable for pre-clinical small animal and 3-D cell culture system studies. In our previous study, we have implemented shear wave elasticity imaging (SWEI) on our high frequency single element system. However, due to attenuation and diffraction, the signal-to-noise ratio (SNR) and estimation accuracy decrease with distance. The measured speed map tends to be incorrect for large region of interest (ROI). In this resear

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35

Wang, Michael Haizhou. "Shear Wave Imaging using Acoustic Radiation Force." Diss., 2013. http://hdl.handle.net/10161/7203.

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<p>Tissue stiffness can be an indicator of various types of ailments. However, no standard diagnostic imaging modality has the capability to depict the stiffness of tissue. To overcome this deficiency, various elasticity imaging methods have been proposed over the past 20 years. A promising technique for elasticity imaging is acoustic radiation force impulse (ARFI) based shear wave imaging. Spatially localized acoustic radiation force excitation is applied impulsively to generate shear waves in tissue and its stiffness is quantified by measuring the shear wave speed (SWS).</p><p>The aim of thi

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Chen, Bo-Rong, and 陳柏融. "Shear Wave Elasticity Imaging for Preclinical Studies." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/22911467537872979857.

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碩士<br>國立臺灣大學<br>生醫電子與資訊學研究所<br>101<br>High frequency ultrasound has been widely used to investigate various mice models of diseases and to evaluate effect and safety of new health care technologies in preclinical studies. Recently, shear wave elasticity imaging has become an important imaging technique because it can provide quantitative results in real time to assist clinical diagnosis. However, most applications of elasticity imaging are currently only available on clinical array systems but not preclinical single element systems. Therefore, it is the purpose of this research is to design, i

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Yengul, Sanjay S. "Shear wave rheometry with applications in elastography." Thesis, 2019. https://hdl.handle.net/2144/34923.

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The goal of elastography is to map the mechanical properties of soft tissues associated with health and disease. The mechanical property of interest in this work is the complex shear modulus, composed of a real part, the storage modulus, which is a measure of elasticity, and an imaginary part, the loss modulus, which is a measure of viscosity. Together, they determine the speed and attenuation of shear waves in the medium. Elastography techniques based on either ultrasound imaging or MRI can image shear wave propagation and thus are capable of measuring shear wave speed and attenuation. Dis

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Chao, Pei-Yu, and 趙珮妤. "Laser Speckle Contrast Shear Wave Imaging: System Development and Applications in Mechanobiology." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/zf76jn.

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博士<br>國立臺灣大學<br>生醫電子與資訊學研究所<br>106<br>The high spatial resolution and motion sensitivity of optical-based shear wave detection have made it an attractive technique in biomechanics studies with potential for improving the capabilities of ultrasound-based shear wave elasticity imaging. In this research, a laser speckle contrast shear wave imaging system was developed. The estimation of shear wave speed is based on the detection of the local blurring of the optical speckle pattern resulting from the mechanical disturbances induced by shear wave propagation. In two-dimensional (2D) imaging, the de

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Maeva, Anna. "High Frequency Shear Wave Imaging: A Feasibility Study In Tissue Mimicking Gelatin Phantoms." Thesis, 2014. http://hdl.handle.net/1807/44041.

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Shear wave (SW) imaging is an ultrasound elastogrpahy technique for estimating the elastic properties of biological tissues. Increasing the frequency would improve both the confinement of the radiation force generating the shear wave, and the imaging spatial resolution. The objectives of the study were to realize a simple high frequency (HF) system for the generation and detection of SW propagation and to implement this system to develop and characterize tissue-mimicking gelatin phantoms (TMGP) for HF SWI with elastic properties in the range of those encountered in biological tissue. A 5 MHz a

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Bouchard, Richard Robert. "Acoustic Radiation Force Impulse-Driven Shear Wave Velocimetry in Cardiac Tissue." Diss., 2010. http://hdl.handle.net/10161/3003.

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<p>Acoustic radiation force impulses (ARFI) have been used to generated transverse-traveling mechanical waves in various biological tissues. The velocity of these waves is related to a medium's stiffness and thus can offer useful diagnostic information. Consequently, shear wave velocimetry has the potential to investigate cardiac disease states that manifest themselves as changes in tissue stiffness (e.g., ischemia).</p><p> The work contained herein focuses on employing ARFI-based shear wave velocimetry techniques, similar to those previously utilized on other organs (e.g., breast, liver),

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Chu, Tang-Ting, and 朱唐廷. "Finite element analysis of strain-stiffening behaviors of tendons:Compared with shear wave elasticity imaging." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/32495950576155872388.

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碩士<br>國立臺灣大學<br>生醫電子與資訊學研究所<br>102<br>The function of tendon is to transmit the energy generated by muscles to the bone to help body movement. Tendons play a key role to regulate the force output by releasing or storing the energy in order to present from avoid taking damages. These functionalities depends on its proper tensile stiffness, i.e., the Young''s modulus E of the tendon along the stretching direction of the tendon. Tendon injuries areoften result from an over-use disease, which and isare closely related to the mechanical loading imposed on the tendon during physical activi

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Alavi, Dorcheh Marzieh. "Quantitative ultrasound imaging during shear wave propagation for application related to breast cancer diagnosis." Thèse, 2014. http://hdl.handle.net/1866/11770.

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Dans le contexte de la caractérisation des tissus mammaires, on peut se demander ce que l’examen d’un attribut en échographie quantitative (« quantitative ultrasound » - QUS) d’un milieu diffusant (tel un tissu biologique mou) pendant la propagation d’une onde de cisaillement ajoute à son pouvoir discriminant. Ce travail présente une étude du comportement variable temporel de trois paramètres statistiques (l’intensité moyenne, le paramètre de structure et le paramètre de regroupement des diffuseurs) d’un modèle général pour l’enveloppe écho de l’onde ultrasonore rétrodiffusée (c.-à-d., la K-

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Farrow, Matthew, J. Biglands, A. M. Alfuraih, R. J. Wakefield, and A. L. Tan. "Novel muscle imaging in inflammatory rheumatic diseases — a focus on ultrasound shear wave elastography and quantitative MRI." 2020. http://hdl.handle.net/10454/18472.

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Yes<br>In recent years, imaging has played an increasing role in the clinical management of patients with rheumatic diseases with respect to aiding diagnosis, guiding therapy and monitoring disease progression. These roles have been underpinned by research which has enhanced our understanding of disease pathogenesis and pathophysiology of rheumatology conditions, in addition to their key role in outcome measurement in clinical trials. However, compared to joints, imaging research of muscles is less established, despite the fact that muscle symptoms are very common and debilitating in many rheu

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Chu, Cheng-An, and 朱振安. "Identifying the Upper Airway Characteristic of Obstructive Sleep Apnea patient with Submental Ultrasound Imaging and Shear Wave Elastography." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/kcvxk2.

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碩士<br>國立臺灣大學<br>臨床牙醫學研究所<br>107<br>Purpose: Obstructive Sleep Apnea syndrome (OSAs) is a sleep breathing disorders of upper airway collapsing during sleep. It mostly caused by the upper airway structure abnormality. According to the previously studies, volume enlargement and low elasticity of upper airway structure may correlate to the occurrence of OSAs. The medical imaging tools of evaluating upper airway included computed tomography (CT), Magnetic resonance imaging (MRI) and Cephalometric x-ray. However, their application was limited by the drawback such as radiation exposure, high cost and

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Zhai, Liang. "Imaging and Characterizing Human Prostates Using Acoustic Radiation Force." Diss., 2009. http://hdl.handle.net/10161/1619.

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<p>Prostate cancer (PCa) is the most common non-cutaneous cancer in men in the United States. Early detection of PCa is essential for improving treatment outcomes and survival rates. However, diagnosis of PCa at an early stage is challenged by the lack of an imaging method that can accurately visualize PCas. Because pathological processes change the mechanical properties of the tissue, elasticity imaging methods have the potential to differentiate PCas from other prostatic tissues. Acoustic radiation force impulse (ARFI) imaging is a relatively new elasticity imaging method that visualizes the

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Tsai, Ssu-Chia, and 蔡思佳. "Detection and Analysis for the Development of Radiation-induced Muscular Tissue Injury by Using Ultrasound Imaging and Shear-wave Elastography." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/00766900112839516581.

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碩士<br>國立臺灣大學<br>醫學工程學研究所<br>103<br>Background: Radiation therapy uses high energy radiation to kill cancer cells to achieve the purpose of cancer treatment. Although radiation therapy can kill cancer cells effectively, it also damages the surrounding normal tissues or organs. The fibrosis of the damaged soft tissue may occur months or years later after treatment. A clear trend of muscle fibrosis can be seen on ultrasound imaging when the patients return for follow up without feeling discomfort or affecting their lifestyle. Purpose: The purpose of this study is to use ultrasound image analysis

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Katsaga, Tatyana. "Geophysical Imaging and Numerical Modelling of Fractures in Concrete." Thesis, 2010. http://hdl.handle.net/1807/24780.

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The goal of this research is to investigate the fundamentals of fracturing processes in heterogeneous materials such as concrete using geophysical methods and dynamic micromechanical models. This work describes how different aspects of fracture formation in concrete can be investigated using a combination of Acoustic Emission (AE) techniques, ultrasonic wave velocity imaging, and high resolution Computed Tomography (CT). Fracture formation and evolution were studied during shear failure of large reinforced concrete beams and compressive failure of concrete samples. AE analysis includes studyin

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Hollender, Peter J. "Mapping Myocardial Elasticity with Intracardiac Acoustic Radiation Force Impulse Methods." Diss., 2014. http://hdl.handle.net/10161/9388.

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<p>Implemented on an intracardiac echocardiography transducer, acoustic radiation force methods may provide a useful means of characterizing the heart's elastic properties. Elasticity imaging may be of benefit for diagnosis and characterization of infarction and heart failure, as well as for guidance of ablation therapy for the treatment of arrhythmias. This thesis tests the hypothesis that with appropriately designed imaging sequences, intracardiac acoustic radiation force impulse (ARFI) imaging and shear wave elasticity imaging (SWEI) are viable tools for quantification of myocardial elastic

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Kuo, Ting Jung, and 郭庭榮. "Quantification of Pulse Wave Velocity of Aorta of Diabetic Patients with Phase Contrast Magnetic Resonance Imaging(Part 1)In Vitro Study of Aortic Wall Shear Stress with Phase Contrast Magnetic Resonance Imaging (Part 2)." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/24572506424039915512.

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碩士<br>大葉大學<br>機械工程研究所碩士班<br>95<br>This thesis consists of two parts. Part I of this thesis is “Quantification of pulse wave velocity of aorta of diabetic patients with phase contrast magnetic resonance imaging.” Part II is ”In-vitro study of aortic wall shear stress with phase contrast magnetic resonance imaging.” In Part I, Compliance of the aorta is an important factor of heart load and a clinically predictor of long-term prognosis in patients with diabetes mellitus and hypertension. Pulse wave velocity (PWV) of aortic blood flow is considered a surrogate for aortic compliance. In this study

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Ouared, Abderrahmane. "Développement d'une nouvelle méthode de caractérisation tissulaire basée sur l'élastographie ultrasonore : application pour le dépistage précoce du cancer du sein." Thèse, 2015. http://hdl.handle.net/1866/13548.

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Le cancer du sein est le cancer le plus fréquent chez la femme. Il demeure la cause de mortalité la plus importante chez les femmes âgées entre 35 et 55 ans. Au Canada, plus de 20 000 nouveaux cas sont diagnostiqués chaque année. Les études scientifiques démontrent que l'espérance de vie est étroitement liée à la précocité du diagnostic. Les moyens de diagnostic actuels comme la mammographie, l'échographie et la biopsie comportent certaines limitations. Par exemple, la mammographie permet de diagnostiquer la présence d’une masse suspecte dans le sein, mais ne peut en déterminer la nature (béni

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