Time: 15:00-16:00, Oct. 25
Abstract:
The last two decades have witnessed changes in our ability to assess multiscale mechanical properties of the human skeleton. Ultrasound has played a critical role in this development. Work conducted in quantitative ultrasound (QUS), taking benefit of the scalability of ultrasound, suggests the existence of significant advantages in ultrasound bone quality assessment, as well as the presence of numerous challenges.
With the development of engineering and methodological solutions to these challenges, QUS methods have provided gains in bone mechanical status assessment, spanning the scales of bone organization ranging from elementary bone structural units to the organ level. These include scanning acoustic microscopy (SAM) and resonant ultrasonic spectroscopy (RUS). These techniques can help in characterizing the anisotropic stiffness in vitro more precisely than mechanical testing and are prone to provide answers to some questions that remain open regarding the multiscale determinants of cortical bone elastic properties. This talk will survey some recent advances in SAM and RUS based on major experimental results particularly within the past decade.
On the other side, a specific appealing aspect of in vivo QUS techniques is their potential to account for important bone quality factors like material properties (i.e., stiffness) or structure (i.e., porosity, thickness), which cannot easily be captured with X-ray densitometry techniques. Ultrasound is now a clinically-accepted modality in the management of osteoporosis. The most accepted diagnostic approaches assess fracture risk from measurements of attenuation and speed of sound of cancellous bone. Although still at an early stage of development, recent QUS approaches using guided waves in cortical bone are promising. We will show how new data acquisition and signal processing procedures are prone to reveal bone properties beyond bone mineral quantity and can be useful in the prediction of osteoporotic fracture risk.
As extensive as they are, these gains still constitute a prelude to what is to come, given the incessant developments of better instrumentation and signal processing techniques.
Bio:
Dr. Laugier serves as an Associate Editor for the IEEE TUFFC, Ultrasonic Imaging, Physics in Medicine journals and is on the Advisory board of Ultrasound in Medicine and Biology. He was Chair for the 2003 World Congress on Ultrasound, the 2004 International Bone Densitometry Workshop and Program Chair for the 2008 Acoustics conference (Annual meeting of the Acousticl Society of America held in Paris), and is a permanent member of the Board of the International Congress on Ultrasonics. He received the Bronze medal of the CNRS, the European Grand Prix for innovation and the medal of the French Society of Acoustics. He is a Fellow of the American Institute for Medical and Biological Engineering (AIMBE), of the Acoustical Society of America (ASA) and of the American Institute for Ultrasound in Medicine (AIUM) and a member of the European Academy of Science. Dr. Laugier has published more than 300 papers and book chapters.
Dr Laugier first began working on medical applications of ultrasound, developing tissue characterization techniques for soft tissue and high-frequency ultrasound imaging for small organs (eye, skin, cartilage) and for small animals. He then focused on the development of innovative quantitative ultrasound techniques in the field of bone. Research centres on understanding the elastic behavior of bone and on developing innovative ultrasound technologies for assessment of bone quality. Much of the science and technological breakthrough in bone quantitative ultrasound, e.g., multiscale ultrasound imaging, guided waves-based technology and resonant ultrasound spectroscopy have been developed in his group. He is cofounder of the spin-off Azal?e, which has been created to develop medical devices using ultrasound-guided waves to measure cortical bone and assess its structural and mechanical properties.
Sist seminar 18210
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