The new method could be used to take precise three-dimensional images of plaques lining arteries, said Ji-Xin Cheng, an associate professor of biomedical engineering and chemistry at Purdue University.
"You would have to cut a cross section of an artery to really see the three-dimensional structure of the plaque," Cheng said. "Obviously, that can't be used for living patients."
The imaging reveals the presence of carbon-hydrogen bonds making up lipid molecules in arterial plaques that cause heart disease. The method also might be used to detect fat molecules in muscles to diagnose diabetes and for other lipid-related disorders, including neurological conditions and brain trauma. The technique also reveals nitrogen-hydrogen bonds making up proteins, meaning the imaging tool also might be useful for diagnosing other diseases and to study collagen's role in scar formation.
"Being able to key on specific chemical bonds is expected to open a completely new direction for the field," Cheng said
Findings are detailed in a paper to be published in Physical Review Letters and expected to appear in the June 17 issue. The findings represent the culmination of four years of research led by Cheng and doctoral student Han-Wei Wang.
The new technique uses nanosecond laser pulses in the near-infrared range of the spectrum. The laser generates molecular "overtone" vibrations, or wavelengths that are not absorbed by the blood. The pulsed laser causes tissue to heat and expand locally, generating pressure waves at the ultrasound frequency that can be picked up with a device called a transducer.
"We are working to miniaturize the system so that we can build an endoscope to put into blood vessels using a catheter," Cheng said. "This would enable us to see the exact nature of plaque formation in the walls of arteries to better quantify and diagnose cardiovascular disease."
Lihong Wang, Gene K. Beare Distinguished Professor of Biomedical Engineering at Washington University in St. Louis, is a pioneer of using the "photoacoustic" imaging of blood vessels based on the absorption of light by the electrons in hemoglobin.
The Purdue researchers are the first to show that a strong photoacoustic signal can arise from the absorption of light by the chemical bonds in molecules. The near-infrared laser causes enough heating to generate ultrasound but not enough to damage tissue.
"You can measure the time delay between the laser and the ultrasound waves, and this gives you a precise distance, which enables you to image layers of the tissues for three-dimensional pictures," Cheng said. "You do one scan and get all the cross sections. Our initial target is cardiovascular disease, but there are other potential applications, including diabetes and neurological conditions."
The approach represents a major improvement over another imaging technique, called coherent anti-Stokes Raman scattering, or CARS, which has been used by the Purdue-based lab to study three-dimensional plaque formation in arteries.
Also leading the research are Michael Sturek, chair of the Department of Cellular and Integrative Physiology at the Indiana University School of Medicine; Robert P. Lucht, Purdue's Ralph and Bettye Bailey Professor of Combustion in Mechanical Engineering; and David Umulis, a Purdue assistant professor of agricultural and biological engineering. Other authors of the paper include Purdue graduate students Ning Chai, Pu Wang and Wei Dou and Washington University postdoctoral researcher Song Hu.
Findings are based on research with pig tissues in laboratory samples and also with live fruit flies.
"You can see fat inside fly larvae, representing the potential to study how obesity affects physiology in humans," Cheng said.
Research funding came from the National Institutes of Health and American Heart Association.
Writer: Emil Venere, 765-494-4709, firstname.lastname@example.org
Source: Ji-Xin Cheng, 765-494-4335, email@example.com
Note to Journalists: Ji-Xin Cheng is pronounced "Gee-Shin." An electronic copy of the paper is available from Emil Venere, Purdue News Service, at 765-494-4709, firstname.lastname@example.org
Emil Venere | EurekAlert!
First transcatheter implant for diastolic heart failure successful
16.11.2017 | The Ohio State University Wexner Medical Center
Theranostic nanoparticles for tracking and monitoring disease state
13.11.2017 | SLAS (Society for Laboratory Automation and Screening)
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
17.11.2017 | Physics and Astronomy
17.11.2017 | Health and Medicine
17.11.2017 | Studies and Analyses