Source: American Institute of Physics (AIP)

Released: Wed 25-Jun-2008, 15:00 ET  Printer-friendly Version

Sound Medicine: Medical Highlights from Upcoming Meeting

Newswise — Sound has a long history in medicine, from the stethoscopes doctors have used since the early 19th century to listen to the internal sounds of the human body to the obstetric ultrasound images so familiar to expectant parents. Now scientists are finding many more advanced applications of sound in medicine.

Sound waves can assess potentially dangerous atherosclerotic plaques, monitor chronic liver disease, and help deliver drugs to particular locations within the body. Ultrasound devices can image tumors deep inside the body, and acoustical energy can be focused upon those tumors as a way of treating cancer. Acoustics is also blending with other disciplines such as psychology and neuroscience to help improve communication for people with speech disorders and hearing problems.

These applications and many more will be described at Acoustics '08 Paris -- the largest ever meeting devoted to the science of acoustics. The meeting will take place Monday June 30 through Friday July 4, 2008 at the Palais des Congrès in Paris, France.

This news release highlights just a few of the biomedical talks at Acoustics '08 Paris. More details on the other 3,500 presentations at the meeting and instructions for journalists who wish to cover the meeting are contained at the bottom of this release.

HIGHLIGHTS IN THIS RELEASE
1) Minimally Invasive Technique Offers New Hope for People with Cancer
2) Microbubbles Offer Potential for New Non-Invasive Therapies
3) Brain-Computer Interface May Helps People to Speak Up
4) Auditory Scene Analysis May Lead to "Smart" Hearing Instruments
5) Virtual Palpation is New Way to Detect Disease
6) Using Ultrasound to Assess Liver Stiffness and Disease
7) Clinical Assessment of Blood Vessel Ultrasound

1) MINIMALLY INVASIVE TECHNIQUE OFFERS NEW HOPE FOR PEOPLE WITH CANCER
A new technique that destroys tumors via thermal ablation may offer new hope to the sickest people with cancer. This new technique developed by a team of researchers from the French National Institute for Health and Medical Research (INSERM) uses interstitial ultrasound applicators that bring the ultrasound source in close contact with the target tissue to be destroyed for efficient heating. Using these probes would allow physicians to reach deep-seated tumors, and the minimally invasive method makes this treatment methodology an option even for people in poor general condition.

In addition to these clinical advantages, this method of treatment offers the potential to allow concurrent monitoring during treatment. This could be a real boon to treatment, explains Cyril Lafon, a member of the research team from INSERM. "When combined with imaging capability, the treatment is safer because the probe can be properly positioned with respect to the tumor and thermal damage can be followed." The team is now working on improving monitoring techniques to bring new non-surgical alternatives to patients who may not be able to withstand surgery and offer new hope for treatment that is precise, safe, and effective.

Cyril Lafon will speak on "Ultrasound interstitial applicators for thermal ablation in liver" (Talk 1pBBa7) on June 30 at 3:00 p.m. in Room 352B.

2) MICROBUBBLES OFFER POTENTIAL FOR NEW NON-INVASIVE THERAPIES
University of Michigan researchers are utilizing microbubbles in therapeutic ultrasound to explore new opportunities to treat disease by non-invasive means with fewer side effects and greater quality of life. J. Brian Fowlkes and his colleagues are exploring two areas with incredible potential to improve treatment and outcomes via methods reminiscent of the 1966 movie "Fantastic Voyage."

Utilizing microbubbles for histotripsy, or the disruption of tissue from the outside of the body, holds particular promise for treating prostate cancer and enlarged prostates, a condition known as Benign Prostatic Hyperplasia. This condition affects nearly 90 percent of men by age 80. Histotripsy ablates prostate tissue by using acoustical energy to create a cavitation field and disrupting target tissues in a controlled way. Scarring is reduced as the tissue is broken down to a subcellular level.

Another application of microbubbles under study uses ultrasonic pulses to create bubbles from small droplets the size of a red blood cell that can be delivered intravenously, occluding tumor vessels and/or delivering therapeutic agents. Further development of these techniques may yield treatment methodologies that will minimize side effects and improve outcomes for patients. J. Brian Fowlkes will speak Monday, June 30 at 3:20 p.m. in Room 352B on "Histotripsy and the developing role of microbubbles in ultrasound therapy" (Talk 1pBBa8).

3) BRAIN-COMPUTER INTERFACE MAY HELP PEOPLE TO SPEAK UP
Functional Magnetic Resonance Imaging (fMRI) is allowing scientists to identify the brain regions responsible for correcting auditory errors -- the differences between how we hear our own speech and what we expect it to sound like. Researchers are now feeding this information into refining what they call the "DIVA Model", a way of modeling neural networks that could enable the design of neural implants and brain-computer interfaces for people with damage to their speech motor output.

Collaborating with Philip Kennedy at Neural Signals Inc. in Georgia, Boston University's Frank Guenther is developing a brain-computer interface that records brain signals from a person's speech motor cortex and transmits them across the scalp to a computer. This computer then decodes these signals into commands for a speech synthesizer, allowing that person to hear what he/she was trying to say in real-time. With practice, using the synthesizer should help someone to improve their sound output.

The long-term goal of the brain-computer interface is to enable almost conversational speech for individuals with locked-in syndromes or diseases that affect speech motor output, such as Amyotrophic Lateral Sclerosis (ALS, or Lou Gehrig's Disease). Other applications of the model include stuttering, apraxia of speech, and other related disorders.

Dr. Frank H. Guenther will speak on Thursday, July 3 at 8:40 a.m. "Involvement of Auditory Cortex in Speech Production" (Talk 4aSCb1) in Room 250B

4) AUDITORY SCENE ANALYSIS MAY LEAD TO "SMART" HEARING INSTRUMENTS
"Smart" algorithms may help those dependent on hearing aids hear better in all situations, whether they are in a crowded stadium or in a library reading room by allowing their hearing device to adjust to different auditory scenes automatically. Matthias Froehlich of Siemens AG is studying how the brain accomplishes the auditory scene analysis and developing ways to use this information to help configure hearing instruments to maximize the hearing capabilities of their users.

The ultimate goal is a completely new kind of hearing aid that "knows" what the wearer wants to listen to and automatically adjusts its own settings accordingly. This would be particularly useful for elderly hearing aid wearers who may be unable or unwilling to make manual adjustments to their hearing instruments to allow them to enjoy the sounds around them, whatever the situation.

Dr. Froehlich will present Talk 1pEAc5, "Auditory scene analysis in hearing instruments" on Monday, June 30 at 5:40 p.m. in Room 353

5) "VIRTUAL PALPATION" IS NEW WAY TO DETECT DISEASE
Using acoustic radiation force, Kathryn Nightingale, Gregg Trahey, and their colleagues at Duke University are developing the capability to "virtually palpate" patients for diagnostic purposes, providing the opportunity to reach deep inside the body where conventional palpation is not possible.

This virtual palpation technique images tissue stiffness differences associated with different pathologies. Focused ultrasound is used to apply localized radiation force to small volumes of tissue for short durations, with resulting tissue displacements mapped using ultrasonic correlation-based methods. Dr. Nightingale compares the technique to extending physicians fingers so they can feel small structures deep within the body.

Acoustic Radiation Force Impulse Imaging, as it is formally known, offers a useful adjunct to conventional ultrasound for clinicians, since images acquired using this method can be compared to conventional ultrasound images to provide additional information and often, improved contrast. Clinical studies using these techniques on various organs including the liver, prostate,breast and heart have demonstrated the utility of this tool, and researchers are now beginning to apply this technology for the detection of liver diseases.

Dr. Kathryn Nightingale will present Talk 5aBBf9," Impulsive acoustic radiation force: imaging approaches and clinical applications" on Friday, July 4 in Room 352 B.

6) USING ULTRASOUND AND SHEAR WAVES TO ASSESS LIVER STIFFNESS AND DISEASE
Human livers are under siege because of a global rise in end-stage liver disease related to obesity, alcoholism, and infectious diseases like hepatitis B, hepatitis C, and HIV. Because the prognosis for people with chronic liver disease is related to the progressive growth of fibrotic liver tissue, the search is on for better alternatives to surgical biopsy for detecting fibrosis. Ultrasound-based transient elastography is one alternative. It quickly and non-invasively provides clinicians with a quantitative measure of liver stiffness, a diagnostic trait that correlates well with the degree of destructive fibrotic growth. Knowledge of liver stiffness enables physicians to detect and treat chronic liver diseases, when they are most treatable.

There's just one hitch: Current use of transient elastography is limited to average-weight adults. Obese adults and children are difficult or impossible to assess with transient elastography. Their body size inhibits the passage of the low-frequency shear waves through the liver. This impedance undermines the usefulness of transient elastography because stiffness score is based on the velocity of a shear wave as it passes through the liver.

Now this may change, thanks to work by Laurent Sandrin and colleagues at Echosens, R&D department in Paris, France. They have developed new probes for children and obese patients, and modified stiffness measurement procedures to extend the applications of transient elastography. (Talk 1pBBb8, "Transient elastography: changing clinical practice in hepatology," will be at 3:20 p.m. on Monday, June 30 in Room 362/363).

7) CLINICAL ASSESSMENT OF BLOOD VESSEL ULTRASOUND
Understanding the mechanics of cardiovascular disease is changing. The old idea of static, clogged "pipes" is now yielding to a more sophisticated concept of cardiovascular disease as an inflammatory process that begins in children as young as 10 years old. The life-threatening end product of this process is an unstable blood vessel lesion-known as a vulnerable plaque-that has developed a specific chemical composition and distinct form (thin, fibrous cap) that render it likely to rupture and lead to heart attack.

Detecting vulnerable plaques would be an immense aid for managing heart disease, the leading cause of death and disability in western nations, but traditional imaging methods don't currently detect vulnerable plaque. Antonius FW van der Steen, and his colleagues at the Erasmus Medical Center in Rotterdam, Netherlands, are working to change this with an emerging technology called intravascular ultrasound palpography.

Once threaded through a catheter to reach the target blood vessel, intravascular ultrasound palpography measures the local strain in vessels caused by vulnerable plaque. These measurements help assess the vulnerable plaque's stability and its likelihood of rupture. Clinical trials now underway are testing the validity of using intravascular ultrasound palpography readings as "biomarkers" to help clinicians evaluate the efficacy of various drugs to treat vulnerable plaque. (Talk 1pBBb2, "Quantitative intravascular ultrasound elasticity imaging as an imaging biomarker in clinical trials," will be at 1:20 p.m. on Monday, June 30 in Room 362/363).

MORE INFORMATION ABOUT ACOUSTICS '08 PARIS
The science of acoustics is a cross-section of diverse disciplines, including fields such as architecture, speech science, oceanography, meteorology, psychology, noise control, physics, marine biology, medicine, and music. Acoustics'08 Paris is the world's largest meeting devoted to this range of topics. It incorporates the 155th Meeting of the Acoustical Society of America (ASA), the 5th Forum Acusticum of the European Acoustics Association (EAA), and the 9th Congrès Français d'Acoustique of the French Acoustical Society (SFA) integrating the 7th EUROpean conference on NOISE control (euronoise), the 9th European Conference on Underwater Acoustics (ecua) and the 60th Anniversary of the SFA.

ABOUT THE ACOUSTICAL SOCIETY OF AMERICA
The Acoustical Society of America is the premier international scientific society in acoustics devoted to the science and technology of sound. Its 7,500 members worldwide represent a broad spectrum of the study of acoustics. ASA publications include The Journal of the Acoustical Society of America-the world's leading journal on acoustics, Acoustics Today magazine, books and standards on acoustics. The Society also holds two major scientific meetings each year. For more information about the Society, visit our Web site, http://asa.aip.org.