Ultrasound Imaging and Therapeutics
Wednesday, April 14, 08:30 - 12:15
Presented by
Presented by Elisa Konofagou (Columbia University, USA) and Constantin Coussios (University of Oxford, UK)
Description
Despite the fact that medical ultrasound is a relatively older field compared to MRI and PET, ongoing advances have allowed to continuously expand as a field in its numerous applications. In the past decade, with the advent of faster processing, specialized contrast agents, understanding of nonlinear wave propagation, novel and real-time signal and image processing and complex ultrasound transducer manufacturing, ultrasound imaging and ultrasound therapy have enjoyed a multitude of new features and clinical applications. The first part of this tutorial will give a short background on the ultrasound physics, ultrasound imaging and image formation, and will end with a short overview of recent breakthroughs and future advances. In its second part, two main recently developed areas will be described: elasticity imaging and ultrasound therapy. The first area employs state-of-the-art signal and image processing techniques in order to estimate the motion and deformation resulting from external or internal mechanical excitation of tissues. The aim is to detect and image tissues that are abnormally softer or harder than the surrounding tissues, such as tumors or infarcted myocardium, and the clinical use of these techniques will be discussed. The second area of ultrasound therapeutics will concentrate on the use of highly focused ultrasound beams using specialized transducer geometry for localized temperature increase deep in tissues and for subsequent heating or ablation of pathological tissue seated deep inside normal tissues. Monitoring techniques using ultrasound-based, elasticity-based and MRI-based techniques will be discussed as well as the current clinical applications.
Part 1: Basics of medical ultrasound (Elisa Konofagou)
1.1 History of diagnostic ultrasound: early attempts to use ultrasound in diagnosis, early equipment configurations
- Overview of clinical applications of diagnostic ultrasound
- Breakthrough and future development of diagnostic ultrasound
1.2 Ultrasound physics
- Wave variables: particle displacement, acoustic pressure, intensity and energy density function
- Factors determining the sound speed
- Reflection, refraction and transmission
1.3 Fundamentals of transducers
- Piezoelectric effect, continuous wave excitation, pulsed excitation and axial resolution
- Half wave resonance, matching and backing layers
- Beam patterns and lateral resolution of non-focused and focused transducers
- Phased array transducers; 1.5D and 2D transducers
1.4 Ultrasound imaging
- A-mode, B-mode and M-mode imaging
- Image display: scan conversion, interpolation algorithms
- Acoustic output of ultrasound imaging system and biological effect of ultrasound
- Doppler effect: Doppler equation, Doppler angle, and Doppler frequency calculation
- Continuous wave Doppler: CWD transducer, wall filter, clinical applications
- Pulsed Doppler: spectral analysis, quadrature detection for directional Doppler, aliasing, PRF vs. maximum velocity and depth
- Methods of deriving color flow imaging; Color Doppler and power Doppler
1.5 Breakthroughs and future development of diagnostic ultrasound
- Contrast agents
- Elastography
- High frequency / molecular imaging
About the speaker
Elisa Konofagou received her B.Sc. degree in Chemical Physics from Université de Pierre et Marie Curie, Paris VI in Paris, France and her M.Sc. degree in Biomedical Engineering from Imperial College of Physics, Engineering and Medicine in London, U.K., in 1992 and 1993, respectively. In 1999, Dr. Konofagou received her Ph.D. frm the University of Houston in Biomedical Engineering for her work on elastography at the University of Texas Medical School in Houston, TX and then pursued her postdoctoral work in elasticity-based monitoring of focused ultrasound therapy at Brigham and Womens Hospital, Harvard Medical School, Boston, MA. Professor Konofagou is currently an Associate Professor of Biomedical Engineering and Director of the Ultrasound and Elasticity Imaging Laboratory at Columbia University, New York, USA. She is also a member of the IEEE Ultrasonics, Ferroelectrics and Frequency Control, the Acoustical Society of America and the American Institute of Ultrasound in Medicine. Her main interests are in the development of novel elasticity imaging techniques and therapeutic ultrasound methods, such as breast elastography, ligament elastography, myocardial elastography, harmonic motion imaging and focused ultrasound therapy with clinical collaborations in the Columbia Presbyterian Medical Center. She is the author of over 60 published papers in the aforementioned fields. Dr. Konofagou is a technical committee member of the Acoustical Society of America and a technical standards committee member of the American Institute of Ultrasound in Medicine. She has also been a special issue editor for the journal of Ultrasonics and is recipient of several awards including from the American Heart Association, the Acoustical Society of America and the Radiological Society of North America.
Part 2: Towards improved delivery and monitoring of ultrasound therapy (Constantin Coussios)
2.1 Linear and non-linear ultrasonics
- Linear and non-linear ultrasound propagation: reflection, transmission and refraction
- Acoustic cavitation
- Applications of non-linearity to medical imaging and drug delivery
2.2 Thermal effects of ultrasound for therapy
- Mechanisms of heat deposition by ultrasound
- Monitoring ultrasound-induced hyperthermia and ablation: Ultrasound and MRI
- Overview of available clinical systems for current and future applications of ultrasound therapy
2.3 Mechanical effects of ultrasound for therapy
- Acoustic streaming
- Acoustic radiation force
- Mechanical effects of inertial and stable cavitation
- Case studies: thrombolysis and lithotripsy
- Future directions
About the speaker
Dr. Constantin-C. Coussios is a tenured Reader (Associate Professor) in Biomedical Engineering at the University of Oxford, where he heads the Biomedical Ultrasonics and Biotherapy Laboratory (BUBL), a research group of some 24 extramurally funded researchers working on a wide array of novel diagnostic and therapeutic ultrasound applications. He obtained his BA (1997), MEng (1998), MA (2001) and PhD (2002) in Engineering from the University of Cambridge (UK), and as an undergraduate and graduate student was the recipient of the Shell European Project Prize (1997), the Greek State Graduate Scholarship (1999-2001), the Acoustical Society of America best student paper award (2001) and the Hamilton Prize (2001). As a post-doctoral researcher at the University of Cincinnati (OH, USA, 2001-2002) and at Boston University (MA, USA, 2002-2003), he was awarded the 2002-2003 F.V. Hunt Post-Doctoral Fellowship in Acoustics by the Acoustical Society of America, given annually to a single researcher worldwide. Dr Coussios serves on the Acoustical Societys Technical Committee on Biomedical Ultrasound and Bioresponse to Vibration and, since 2006, has also been a Board member and the Secretary-General of the International Society for Therapeutic Ultrasound. He has published over 85 research outputs in peer-reviewed journals and conferences, and has served as Editor of the Proceedings of the 6th International Symposium on Therapeutic Ultrasound and as guest editor of a special issue on High-Intensity Focused Ultrasound for the International Journal of Hyperthermia. He frequently serves as a panel member and reviewer for several US (NIH/NIBIB) and European funding bodies (EPSRC, BBSRC), and as a reviewer for all major international journals in the fields of acoustics and ultrasonics (J. Acoust. Soc. Am, Ultrasound Med. Biol., Ultrasonics, Ultrasonics Sonochem., IEEE Ultrasonics). In 2007, he was awarded the UKs Institute of Acoustics Young Investigator Award for Innovation in Acoustical Engineering, and was selected as one of seven nationwide recipients of a Challenging Engineering Award by the Engineering and Physical Sciences Research Council (UK). In 2009, he was elected as the youngest Fellow of the Acoustical Society of America.
Material
Copy of slides and reprints
[1] E.E. Konofagou, Ultrasonic Imaging, Handbook of Biomedical Technology and Devices, Editors: James E. Moore and George Zouridakis, CRC press, 9-1 9-30, 2004.
[2] E.E. Konofagou, Quo vadis Elasticity Imaging?, Ultrasonics 42, 331-336, 2004.
[3] C.-C. Coussios and R.A. Roy, Applications of Acoustics and Cavitation to Non-Invasive Therapy and Drug Delivery, Annual Review of Fluid Mechanics 40, 395-420, 2008.
[4] C.-C. Coussios, C.H. Farny, G. ter Haar and R.A. Roy, Role of Acoustic Cavitation in the Delivery and Monitoring of Cancer Treatment by High Intensity Focussed Ultrasound (HIFU), International Journal of Hyperthermia 23(2), 105-120, 2007.
[5] M. Gyongy and C.-C. Coussios, Passive Mapping of Cavitation Activity during Therapeutic Ultrasound Exposure, IEEE Transactions on Biomedical Engineering, 2009, in press (DOI:10.1109/TBME.2009.2026907).