Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


A Probe, Not an Echo


Non-Invasive and Safe, a New USC System Images and Differentiates Soft Tissue With Unprecedented Detail and Precision
Researchers at the University of Southern California’s Viterbi School of Engineering have successfully demonstrated a novel “High-resolution Ultrasonic Transmission Tomography” (HUTT) system fthat offers 3D images of soft tissue that are superior to those produced by existing commercial X-ray, ultrasound or MRI units.

Vasilis Marmarelis, a professor of biomedical engineering at the Viterbi School, presented HUTT images of animal organ tissue in San Diego at the 28th International Acoustical Imaging Symposium on March 21st.

According to Marmarelis, HUTT offers nearly order-of-magnitude improvement in resolution of structures in soft tissue (i.e., 0.4 mm, compared to 2 mm for the best alternatives). Several other features promise to make the technology a scientific and clinical tool of great power:

Robust algorithmic tools enable HUTT to differentiate separate types of tissue based on their distinctive “frequency-dependent attenuation” profiles, that should allow clinicians to distinguish malignant lesions from benign growths in a non-invasive and highly reliable manner. In addition to improved resolution, the system can locate tissue features with extreme precision in a objective, fixed-coordinate 3D grid, crucial for guiding surgical procedures.

Scans can be performed in a matter of a few minutes and because they are ultrasonic, they do not use potentially harmful ionizing radiation. The system requires a minimum of special pre-scan procedures and appears likely, in clinical use, to be more comfortable for patients than alternatives. "The HUTT imaging system is a novel and potentially very useful approach to diagnostic ultrasound,” said Dr. Phillip W. Ralls, a professor and vice chair in the USC Keck School of Medicine department of radiology. “The potential clinical benefits of the superb images obtained by this completely safe, non-invasive technique are very exciting."

According to Marmarelis, the key features distinguishing HUTT from all previous ultrasound imaging systems is the use of multi-band analysis with sub-millimeter ultrasonic transducers in transmission mode, rather than the commonly used echo mode, to create the 3-D image. He explains that in traditional hand-held ultrasound systems, sound waves are broadcast into the tissue, and the echoes produce an image of the reflecting interfaces – that is, the sound transmitter and the receiver are both on the same side of the sample.

However, only a tiny fraction of the transmitted sound comes back as echo on soft tissues, while a much larger fraction (about 2000 times bigger) is transmitted through the soft tissue. Using the sound transmitted through tissue allows the formation of better images with greater clarity and resolution. A hand-held apparatus cannot objectively locate objects in 3D space (in a fixed-coordinate system), but only allows the user to subjectively observe where an object is in relation to other observable structures. Therefore, it is operator-dependent.

The HUTT system transmits an extremely short ultrasonic pulse (about 250 nanosecond) of 4-12 megahertz frequency (far above human hearing) and picks up the pulse on the other side after it has traveled through the imaged object. The transmitted pulses come from an array of very small ultrasonic transducers of sub-millimeter dimensions. A parallel array of transducers on the other side receives the pulses after they travel through the imaged tissue.

A sophisticated coding/decoding signal scheme recognizes a small “sweet spot” of the signal coming from the opposite transducer, and only that transducer, and ignores all other pulses transmitted by neighboring transducers. The transducer is able to distinguish the right signal from the right transducer by using coding that is almost identical to that used by a cell phone to detect signals sent to its number -- and its number only -- from the flood of electronic signals on the air at any given time.

When the transducer captures the signal, it is processed with advanced signal processing algorithms, specially developed by Marmarelis’ group, to form the multi-band images. Different kinds of tissue allow slightly more, or slightly less of the pulse through -- the loss is called “attenuation,” and varies according to the type of tissue, and the frequency of the pulse. "Typically the resulting images represent minute variations in relative attenuation over various frequency bands and they define the different sections of the tissue in the image,” said Marmarelis.

The two arrays, transmitter and receiver, are mounted on opposite sides of a drum that spins as it rises around the object (which is suspended in water), creating a stack of tomographic image slices which visualization algorithms turn into 3D images.

In the first set of experiments using the HUTT system, the Marmarelis team easily located a set of small metal balls smaller than a millimeter in diameter embedded in agar medium. Many critical refinements occurred during the five-year process of development, as the team gained proficiency in imaging animal tissue, notably sheep kidneys and bovine liver.

The most critical feature of the HUTT imaging technology is its potential to reliably differentiate types of tissue based on their multi-band signatures caused by their varying attenuation patterns. This promises to allow non-invasive detection of lesions in clinical diagnosis, which represents the “holy grail” of medical imaging.

The team found it possible to identify various anatomical structures within the kidney based on their distinctive attenuation characteristics, so that computerized algorithms could display in color-coded fashion one tissue in red, another in green, and so forth – thus assisting visualization in 3D.

The technology could also be used to isolate one type of tissue , allowing, for example, all the blood vessel structures to be displayed alone and studied.

“Preliminary results on a sheep kidney show exquisite anatomic and tissue detail,” commented radiologist Ralls. Working with Marmarelis on the project are post-doctoral researchers Drs. Dae C. Shin, Jeong-Won Jeong, Changzheng Huang, and Syn-Ho Do.

Marmarelis is co-director of the Biomedical Simulations Resource (BMSR), an NIH-funded center for the advancement research in biomedical modeling; and also holds an appointment in the Viterbi School’s Electrical Engineering Department.

Marmarelis’ work was funded by the Alfred E. Mann Institute for Biomedical Engineering at the University of Southern California.

Eric Mankin | EurekAlert!
Further information:

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Space observation with radar to secure Germany's space infrastructure

Satellites in near-Earth orbit are at risk due to the steady increase in space debris. But their mission in the areas of telecommunications, navigation or weather forecasts is essential for society. Fraunhofer FHR therefore develops radar-based systems which allow the detection, tracking and cataloging of even the smallest particles of debris. Satellite operators who have access to our data are in a better position to plan evasive maneuvers and prevent destructive collisions. From April, 25-29 2018, Fraunhofer FHR and its partners will exhibit the complementary radar systems TIRA and GESTRA as well as the latest radar techniques for space observation across three stands at the ILA Berlin.

The "traffic situation" in space is very tense: the Earth is currently being orbited not only by countless satellites but also by a large volume of space...

Im Focus: Researchers Discover New Anti-Cancer Protein

An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.

The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...

Im Focus: Researchers at Fraunhofer monitor re-entry of Chinese space station Tiangong-1

In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.

Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...

Im Focus: Alliance „OLED Licht Forum“ – Key partner for OLED lighting solutions

Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.

They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...

Im Focus: Mars' oceans formed early, possibly aided by massive volcanic eruptions

Oceans formed before Tharsis and evolved together, shaping climate history of Mars

A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

New solar solutions for sustainable buildings and cities

23.03.2018 | Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

Latest News

For graphite pellets, just add elbow grease

23.03.2018 | Materials Sciences

Unique communication strategy discovered in stem cell pathway controlling plant growth

23.03.2018 | Agricultural and Forestry Science

Sharpening the X-ray view of the nanocosm

23.03.2018 | Physics and Astronomy

Science & Research
Overview of more VideoLinks >>>