A new device that combines two microimaging technologies can reveal both the detailed anatomy of arterial linings and biological activities that, in coronary arteries, could indicate the risk of heart attacks or the formation of clots in arterial stents.
In their report receiving early online release in Nature Medicine, Massachusetts General Hospital (MGH) investigators describe using an intra-arterial catheter combining both optical frequency-domain imaging (OFDI) and near-infrared fluorescence (NIRF) imaging to obtain simultaneous structural and molecular images of internal arterial surfaces in rabbits.
"The ability to measure both microstructural and molecular information from the same location in the artery wall could provide a much better diagnostic tool for assessing vascular pathology, information that is highly relevant for diagnosing coronary artery disease, vulnerable plaque and evaluating stent healing," says Gary Tearney, MD, PhD, of the Wellman Center for Photomedicine and the MGH Pathology Department, co-senior author of the article.
Developed at the Wellman Center, OFDI utilizes a fiberoptic probe with a constantly rotating laser tip to create detailed molecular images of interior surfaces such as arterial walls. While OFDI can be used to guide procedures like coronary artery angioplasty and to confirm the correct positioning of metal stents inserted to keep cleared arteries open, its ability to determine important details of stent healing is limited. Properly healed stents become covered with endothelium, the same tissue that normally coats the arterial surface; but stents can become coated with the clot-inducing protein fibrin, which may put patients at risk for stent thrombosis – a clot that blocks bloodflow through the stent – and OFDI cannot determine the molecular composition of tissue covering a stent.
Intravascular NIRF technology was developed in the MGH Cardiovascular Research Center (CVRC), in collaboration with colleagues at the Technical University of Munich, and uses special imaging agents to detect cells and molecules involved in vascular processes like clotting and inflammation. Recognizing the potential advantage of combining both technologies, the Wellman researchers worked with the MGH-CVRC team, led by Farouc Jaffer, MD, PhD, of the MGH Heart Center to develop an integrated OFDI-NIRF imaging system incorporated in the same intravascular probe used for OFDI alone.
The team first confirmed that the system could provide detailed structural images of a stent implanted in a cadaveric human coronary artery and could accurately identify the presence of fibrin on the stent. In a series of experiments in living rabbits, the OFDI-NIRF system was able to detect fibrin on implanted stents – including areas where it was not detected by OFDI alone – and to identify the presence of both atherosclerotic plaques and enzymatic activity associated with inflammation and plaque rupture. The enzyme signal detected by NIRF was not uniform throughout the imaged plaques, indicating biological differences that could be relevant to prognosis and treatment planning.
"At present we are not able to predict which patients may develop stent thrombosis, but integrated OFDI-NIRF can assess many key factors linked to the risk of clot formation," says Jaffer, co-senior author of the Nature Medicine report. "If OFDI-NIRF is validated in clinical studies, patients at risk for stent thrombosis could undergo a 'stent checkup' to determine how well the stent is healing. Patients with unhealed stents could be advised to take or continue taking specific anti-clotting medications. Patients with well-healed stents, on the other hand, could potentially discontinue anti-clotting medications, which can cause excess bleeding." Clinical adoption of the integrated technology will require FDA approval of the molecular contrast agents used in NIRF.
Tearney is a professor of Pathology and Jaffer an assistant professor of Medicine at Harvard Medical School. Hongki Yoo, PhD, of the MGH Wellman Center and Jin Won Kim, MD, PhD, MGH Cardiovascular Research Center, are co-lead authors of the Nature Medicine report. Additional co-authors are Milen Shishkov, PhD, Eman Namati, PhD, and Brett Bouma, PhD, Wellman Center; Jason McCarthy, PhD, MGH Center for Systems Biology; Theodore Morse, PhD, and Roman Shubochkin, PhD, Boston University Photonics Center; and Vasilis Ntziachristos, PhD, Technical University of Munich.
The study was supported by grants from the National Institutes of Health, the Center for Integration of Medicine and Innovative Technology, the American Heart Association, Howard Hughes Medical Institute and the CardioVascular Research Foundation. Massachusetts General Hospital has filed patent applications on the combined OFDI and NIRF technology.
Celebrating the 200th anniversary of its founding in 1811, Massachusetts General Hospital (http://www.massgeneral.org) is the original and largest teaching hospital of Harvard Medical School. MGH conducts the largest hospital-based research program in the United States, with an annual research budget of nearly $700 million and major research centers in AIDS, cardiovascular research, cancer, computational and integrative biology, cutaneous biology, human genetics, medical imaging, neurodegenerative disorders, regenerative medicine, reproductive biology, systems biology, transplantation biology and photomedicine.
Sue McGreevey | EurekAlert!
Gentle sensors for diagnosing brain disorders
29.09.2016 | King Abdullah University of Science and Technology
New imaging technique in Alzheimer’s disease - opens up possibilities for new drug development
28.09.2016 | Lund University
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.
Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
21.10.2016 | Health and Medicine
21.10.2016 | Information Technology
21.10.2016 | Materials Sciences