America Latina En/Em Foco

Webinar #3: 30 August, 2021 at 2:00pm EDT (UTC -4:00)

Featured Topic: Acoustic Vortex Beams - From Particle Levitation in Air to Cell Manipulation

Joao Luis Ealo Cuello

Joao Luis Ealo Cuello

Main Talk

Electroactive Diffraction Gratings: An Efficient Alternative for High-Quality Airborne Ultrasound Vortex Beam Generation

Acoustic vortex beams (AVB) have shown great potential in different emerging applications, such as contactless particle manipulation, transfer of angular momentum to matter, acoustic imaging, communications, and more recently, in biomedical applications. Different methods for AVB generation have been proposed, e.g., physically spiral sources, phase-driven sources, passive metastructured devices and electroactive spiral gratings.  Notably, most of them have been developed in water, whereas airborne technologies offer interesting advantages, such as the free access to the manipulated sample.

In this work an efficient technique to easily generate high-quality structured acoustic beams in air is presented. This new approach eliminates reflection losses included in previously reported passive approaches that combine an acoustic source with a diffraction grating. This is possible by converting the grating into an emitter. To demonstrate the versatility of this approach, active spiral-shaped diffraction gratings were fabricated to generate AVB over a broad range of frequencies, i.e., from 70 kHz to beyond 300 kHz, in air. By varying the excitation frequency, a fine and continuous tuning of the focal length of the resultant AVB can be achieved, i.e., the beam can be axially steered while their spatial distribution is preserved. Experimental results from two grating prototypes are included: an Archimedean spiral able to generate simultaneous higher order Bessel beams with different topological charges along the propagation axis and a spiral-Fresnel Zone Plate that allows for sharply focused AVG. The experiments show a good agreement with simulations.  The versatility and simplicity of the fabrication process make this technique highly suitable for emerging applications such as particle manipulation, imaging, and transfer of angular momentum to matter. A comparison between the different fabrication methods reported for AVB generation is included in this presentation.

Glauber Silva

Glauber Silva

Talk #2

3D Printed Acoustofluidic Devices for Biospectroscopy Applications

Acoustofluidic devices combine the forces and torques produced by ultrasonic waves with microfluidics technology to separate, enrich, pattern, and rotate cells, bacteria, and other microorganisms. In this talk, I will discuss the physical principles of 3D printed acoustofluidic devices used for cell levitation and aggregation. The cellular aggregate is formed in a controlled microenvironment at hundreds of micrometers above the device substrate. This is particularly suitable for Raman biospectroscopy, where signal interferences from the substrate are avoided. In turn, the Raman spectrum reveals the chemical bonds present in a cell. Also, the aggregation stability allows for individual cell Raman-spectrum acquisition. Acoustofluidic-assisted biospectroscopy of murine macrophages and red blood cells is illustrated with preferred quality over ordinary Raman strategies.

David Espindola

David Espindola

Moderator

Dr. David Espíndola was born in Chillán, Chile, in 1986. He received the Ph.D. degree in physics from the Universidad de Santiago de Chile, Santiago, Chile, in 2012. As part of his Ph.D. dissertation, he studied the interaction wave-particle in granular materials. He pursued post-doctoral research at the Institut d’Alembert, Sorbonne Université, Paris, France, where he started conducting research on medical ultrasound. He also held a post-doctoral position with The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA, where he also was a Research Assistant Professor. He is currently an Associate Professor at the Instituto de Ciencias de la Ingeniería at the Universidad de O’Higgins in Chile. His research interests are the linear and nonlinear elastic wave propagation in soft materials, ultrasound super-resolution imaging and the elasto-acoustics in complex medium.

Webinar #2: 28 June, 2021 at 2:00pm EDT (UTC -4:00)

Featured Topic: Quantitative Ultrasound and High Frame Rate Volume Imaging

Ivan

Ivan Miguel Rosado Mendez, Ph.D.

Main Talk

Quantitative Ultrasound in Obstetrics and Neonatology

Quantitative Ultrasound (QUS) has the potential to provide noninvasive biomarkers of tissue structure and function in a practical and safe way. This talk will cover applications of two QUS methods, shear wave elasticity imaging and ultrasound backscatter spectroscopy, for the assessment of normal remodeling and damage of structurally complex tissues: the uterine cervix and the neonatal brain. In the cervix, shear wave elasticity imaging is investigated to analyze the frequency dependence of the phase velocity (dispersion) to learn about the structural basis of the cervical remodeling process during pregnancy. In the neonatal brain, ultrasound backscatter spectroscopy is being investigated as a potential tool for detecting cell death caused by different insults, such as long exposures to anesthetics. The talk will conclude with a discussion on the perspective for an extended application of these techniques. 

HeadshotVerasonics

Miguel Bernal

Industry Speaker

High Frame Rate Volume Imaging through Sparse Random Aperture Compounding

High frame-rate volume imaging (HFVI) has become an important area of research in the last few years since it provided high temporal resolution necessary for advanced image processing. Unfortunately, HFVI usually requires ultrasound systems with a large channel count to achieve rates in the kHz order. These systems are usually expensive which makes their use limited to a few laboratories around the world. In 2020, Verasonics introduced the concept of Sparse Random Aperture Compounding (SRAC) to help overcome this limitation. SRAC was developed for ultrasound systems with a significantly lower number of channels than elements in a matrix probe. The idea is to perform compounding of random apertures to balance image quality and frame rate. In the current work we studied the impact of random aperture optimization on the image quality and evaluated the compounding of complementary and non-complementary random apertures. While our previous study showed the benefits of using SRAC for HFVI, random aperture optimization is crucial to improve image quality while preserving high frame rates.

Roberto Lavarello

Roberto Lavarello

Moderator

Roberto Lavarello received his B.Sc. degree in Electronics Engineering from the Pontificia Universidad Católica del Perú in 2000, and his M.Sc. and Ph.D. degrees in Electrical and Computer Engineering from the University of Illinois at Urbana-Champaign in 2005 and 2009, respectively. He is currently a full professor at the Department of Engineering of the Pontificia Universidad Católica del Perú and the director of the Medical Imaging Laboratory, the M.SC. in Biomedical Engineering, and the Ph.D. in Engineering programs from the same institution. His research is primarily focused on the reconstruction and processing of images for the non-invasive assessment of pathological conditions. He is a senior member of IEEE and a former Fulbright scholarship recipient. He served as an Associate Editor for the IEEE Transactions on Biomedical Engineering (2010-2012) and is currently an Associate Editor for the IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control and the IEEE Transactions on Medical Imaging, and an editorial board member for the IEEE Open Access Journal of Engineering in Medicine and Biology. He has served as IEEE EMBS Peru Section Chapter chair (2014-2016) and is currently the R9 representative at the IEEE EMBS AdCom (2017-2022), the chair-of the IEEE Transactions on Medical Imaging Steering Committee, the chair of the the IEEE International Symposium on Biomedical Imaging Steering Committee, the co-chair of the backscatter coefficient group of the the AIUM/QIBA Pulse-Echo Quantitative Ultrasound Biomarker committee. and a member of the IEEE EMBS Technical Committee on Biomedical Imaging and Image Processing, the IEEE SPS Technical Committee on Bio Imaging and Signal Processing, the Technical Program Committee of the IEEE International Ultrasonics Symposium, and the IEEE UFFC Diversity and Inclusion committee.

Webinar #1: 31 May, 2021 at 2:00 PM EDT (UTC-4:00)

Featured Topic: Breast Cancer Ultrasound Imaging

image (2)

Ana B. Ramirez

Main Talk

Comparing Full Waveform Inversion Methods for Ultrasound Imaging for Breast Cancer Detection

Current ultrasound imaging techniques use only part of the information enclosed in the recorded high-frequency sound waves limiting the quality of the information present in the reconstructed image. Advanced ultrasound imaging methods, known as full waveform inversion, use all available information enclosed in the recorded field – including multiple scattering, dispersion, and diffraction effects – to improve the image quality and give accurate quantitative information about the tissue parameters. Full-wave inversion (FWI) may be implemented in either the time or the frequency domain but determining which method should be used is not simple. In this webinar, we will discuss two different non-linear FWI imaging methods: time-domain inversion (TDI) and frequency-domain contrast source inversion (CSI). The methods were tested on the reconstruction of the same synthetic data; a 2-D scan from a circular transducer array enclosing a cancerous breast model. Both methods were evaluated in noise-free and noisy scenarios. Also, the reciprocity of sources and receivers was evaluated as well as the computational complexity of the methods

image (1)

Carla Silva Perez

Early-career Short Talk

Lymphedema, in Survivors of Breast Cancer

Current ultrasound imaging techniques use only part of the information enclosed in the recorded high-frequency sound waves limiting the quality of the information present in the reconstructed image. Advanced ultrasound imaging methods, known as full waveform inversion, use all available information enclosed in the recorded field – including multiple scattering, dispersion, and diffraction effects – to improve the image quality and give accurate quantitative information about the tissue parameters. Full-wave inversion (FWI) may be implemented in either the time or the frequency domain but determining which method should be used is not simple. In this webinar, we will discuss two different non-linear FWI imaging methods: time-domain inversion (TDI) and frequency-domain contrast source inversion (CSI). The methods were tested on the reconstruction of the same synthetic data; a 2-D scan from a circular transducer array enclosing a cancerous breast model. Both methods were evaluated in noise-free and noisy scenarios. Also, the reciprocity of sources and receivers was evaluated as well as the computational complexity of the methods

Chris Korte

Chris de Korte

Moderator

Chris L. de Korte is a Professor of Medical Ultrasound Techniques at Radboud University Medical Center since 2015 and a professor of medical ultrasound imaging at the University of Twente since 2016. He studied electrical engineering at the Eindhoven University of Technology. In 1999, he obtained his Ph.D. at the Biomedical Engineering Group of the Thoraxcentre, Erasmus University Rotterdam on his thesis Intravascular Ultrasound Elastography. In 2002 he joined the Clinical Physics Laboratory, Department of Pediatrics of the Radboud University Nijmegen Medical Center of which he became head in 2004. In 2006 he was registered as Medical Physicist. Since 2012, he is chair of the Medical UltraSound Imaging Centre at the Department of Medical Imaging: Radiology of Radboud University Medical Centre. His research is on functional imaging using Ultrasound with a focus on cardiovascular and oncological applications. For his research, he received multiple grants from the Dutch Technology Foundation (STW) and a VENI (2000), VIDI (2006), and VICI (2011) grant from The Netherlands Organization for Scientific Research (NWO). In 2018, a consortium under his leadership was awarded the NWO-TTW Perspectief grant (4M euros). Prof. de Korte is president of the Netherlands Society for Medical Ultrasound (NVMU) and national delegate of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB). He is an associate editor for IEEE Transactions on UFFC-S and the Journal of Medical Ultrasonics. He serves as an editorial board member of Ultrasound in Medicine and Biology and the Journal of the British Medical Ultrasound Society and is a member of the Technical Program Committee of the IEEE International Ultrasonics Conferences.

IEEE websites place cookies on your device to give you the best user experience. By using our websites, you agree to the placement of these cookies. To learn more, read our Privacy Policy.