Combined arterial imaging technology reveals both structural and metabolic details

November 6, 2011, Massachusetts General Hospital
Combined optical frequency-domain imaging and near-infrared fluorescence image of the inner surface of a rabbit artery shows an implanted arterial stent (blue) and fibrin deposits (red-yellow). By revealing both structural and molecular detail, OFDI-NIRF may improve diagnosis of coronary artery disease and help evaluate stent healing. Credit: Hongki Yoo, PhD, and Jin Won Kim, MD, PhD; laboratories of Gary Tearney MD, PhD, and Farouc Jaffer, MD, PhD, Massachusetts General Hospital

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 could provide a much better for assessing vascular pathology, information that is highly relevant for diagnosing , 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 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 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 , 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.

Explore further: Near infrared fluorescence lights up hidden blood clots

Related Stories

Near infrared fluorescence lights up hidden blood clots

June 6, 2011
Research presented at SNM's 58th Annual Meeting may mark the expansion of a novel imaging agent for an optical technique called near-infrared fluorescence (NIRF), which uses light energy to glean information about cells and ...

High-resolution imaging technology reveals cellular details of coronary arteries

July 10, 2011
Researchers at the Wellman Center for Photomedicine at Massachusetts General Hospital (MGH) have developed a one-micrometer-resolution version of the intravascular imaging technology optical coherence tomography (OCT) that ...

Stents may reduce heart attacks by delivering downstream medication

September 15, 2011
Researchers at Cleveland Clinic have discovered that cardiac patients receiving medicated stents -- a procedure that occurs often when blood vessels are blocked -- have a lower likelihood of suffering heart attacks or developing ...

Recommended for you

Researchers illustrate how muscle growth inhibitor is activated, could aid in treating ALS

January 19, 2018
Researchers at the University of Cincinnati (UC) College of Medicine are part of an international team that has identified how the inactive or latent form of GDF8, a signaling protein also known as myostatin responsible for ...

Bioengineered soft microfibers improve T-cell production

January 18, 2018
T cells play a key role in the body's immune response against pathogens. As a new class of therapeutic approaches, T cells are being harnessed to fight cancer, promising more precise, longer-lasting mitigation than traditional, ...

Weight flux alters molecular profile, study finds

January 17, 2018
The human body undergoes dramatic changes during even short periods of weight gain and loss, according to a study led by researchers at the Stanford University School of Medicine.

Secrets of longevity protein revealed in new study

January 17, 2018
Named after the Greek goddess who spun the thread of life, Klotho proteins play an important role in the regulation of longevity and metabolism. In a recent Yale-led study, researchers revealed the three-dimensional structure ...

The HLF gene protects blood stem cells by maintaining them in a resting state

January 17, 2018
The HLF gene is necessary for maintaining blood stem cells in a resting state, which is crucial for ensuring normal blood production. This has been shown by a new research study from Lund University in Sweden published in ...

Magnetically applied MicroRNAs could one day help relieve constipation

January 17, 2018
Constipation is an underestimated and debilitating medical issue related to the opioid epidemic. As a growing concern, researchers look to new tools to help patients with this side effect of opioid use and aging.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.