A variety of advanced techniques have been developed to characterize the atherosclerotic plaque, including multidetector spiral computed tomography, magnetic resonance imaging, intravascular ultrasound, optical coherent tomography and intravascular near infrared spectroscopy.
Pu Wang and his colleagues from Purdue University, West Lafayette, and Indiana University School of Medicine (USA) now developed a promising new one: They employ an optical window between 1600 nm and 1850 nm for bond-selective deep tissue imaging. Label-free imaging of atherosclerotic plaques can be performed through optical excitation of first overtones of CH bonds and acoustic detection of the generated ultrasound waves in this previously underappreciated optical window.
Until now, the consensus was that the gold optical window lies between 650 and 1300 nm and that it stops at 1300 nm due to significant water absorption at longer wavelengths. The scientists noted that water absorption in the region beyond 1300 nm is modulated by the vibration transition of H2O: They observed a significant valley between 1600 and 1850 nm, where the absorption coefficient of pure water is at the same level as that of heme proteins in whole blood around 800 nm.
Considering the reduced scattering and diminished phototoxicity at longer wavelength excitation, the wavelength region from 1600 to 1850 nm is appealing as a new optical window for deep tissue imaging (light red shadow region). Importantly, the first overtone of CH vibration is located at the same window. Using this new window to carry out photoacoustic imaging, the scientists found a 5 times enhancement of photoacoustic signal by first overtone excitation of the methylene group CH2 at 1730 nm, compared to the second overtone excitation at 1210 nm.This enhancement allowed 3D mapping of intramuscular fat with improved contrast and of lipid deposition inside an atherosclerotic artery wall in the presence of blood. Moreover, lipid and protein could be differentiated based on the first overtone absorption profiles of CH2 and methyl group CH3 in this window.
Selective vibrational photoacoustic microscopy imaging of collagen and lipids heralds the potential in diagnosis of vulnerable plaques through detection of the thickness of the collagen cap and the location of the lipid-laden plaque inside the arterial wall without molecular labeling that could alter tissue composition. (Text contributed by K. Maedefessel-Herrmann)
J. Biophotonics, Volume 5, Issue 11 (2012)
Journal of Biophotonics publishes cutting edge research on interactions between light and biological material. The journal is highly interdisciplinary, covering research in the fields of physics, chemistry, biology and medicine. The scope extends from basic research to clinical applications. Connecting scientists who try to understand basic biological processes using light as a diagnostic and therapeutic tool, the journal offers a platform where the physicist communicates with the biologist and where the clinical practitioner learns about the latest tools for diagnosis of diseases. JBP offers fast publication times: down to 20 days from acceptance to publication. Latest Journal Impact Factor (2010): 4.240 (ISI Journal Citation Reports 2010)
Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY
NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
20.07.2018 | Power and Electrical Engineering
20.07.2018 | Information Technology
20.07.2018 | Materials Sciences