Noninvasive imaging of carotid artery plaque with MRI can accurately predict future cardiovascular events like strokes and heart attacks in people without a history of cardiovascular disease, according to a new study published online in the journal Radiology.
Researchers have long known that some arterial plaque is more dangerous because of its vulnerability to rupture. MRI can discern features of vulnerable plaque, such as a lipid core with a thin fibrous cap. This ability makes MRI a potentially valuable tool for identifying patients at risk for subsequent cardiovascular events.
This shows transverse gadolinium-enhanced T1-weighted MR images obtained superior to the carotid artery bifurcation in a 72-year-old man. L = ICA lumen. (a) Low-signal-intensity calcium (arrow) and lipid core (arrowheads) can be seen. (b) Note contouring of the ICA. The outer adventitial wall (red), lipid core (blue), calcification (green), and vessel lumen (purple) are visible.
Credit: Radiological Society of North America
To study the predictive value of MRI plaque imaging, researchers performed carotid artery ultrasound and MRI on 946 asymptomatic patients from the Multi-Ethnic Study of Atherosclerosis (MESA). The carotid arteries are the large vessels located on each side of the neck that carry oxygenated blood to the front part of the brain. They are highly accessible for imaging, and their condition tends to mirror that of the coronary arteries that supply the heart with oxygenated blood.
The researchers used ultrasound to assess carotid wall thickness and MRI to define carotid plaque composition and the remodeling index, a measure of changes in vessel size. Imaging results were compared with cardiovascular events, including heart attacks, stroke and death, for an average of 5.5 years after examination.
"We studied asymptomatic individuals with a low risk of cardiovascular events at baseline and used noninvasive imaging to predict the risk of an event downstream," said David A. Bluemke, M.D, Ph.D., from the National Institutes of Health Clinical Center in Bethesda, Md. "This is the first population-based prospective study to determine if vulnerable plaque features by MRI add to the risk of a cardiovascular event beyond the traditional risk factors."
Cardiovascular events occurred in 59 of the patients. Abnormal thickening of the carotid artery wall and the presence of a lipid core and calcium in the internal carotid artery on MRI were significant predictors of subsequent events. A lipid core was present in almost half of the patients who had an event, compared with only 17.8 percent of those who did not have an event.
"The primary factors that predicted future risk were measures of vessel wall thickness in combination with the presence or absence of a lipid core," Dr. Bluemke said. "The presence of a lipid core was 50 percent more common in people who had subsequent events."
Use of MRI improved the reclassification of baseline cardiovascular risk in the study group. When both the carotid remodeling index and lipid core were used for risk stratification, approximately 16 percent more patients with events and 7 percent without events were correctly reclassified compared with the use of traditional risk factors.
"The results bolster the use of MRI as a surrogate marker of efficacy in therapeutic studies and point to a role in determining which patients might need more aggressive treatments," Dr. Bluemke said. "As risk factor prediction gets better, we'll be able to screen more intelligently and use more intensive treatments in those individuals who face a higher risk of cardiovascular events."
Dr. Bluemke noted that sequences for plaque composition could be readily added to existing carotid MRI angiography protocols for clinical purposes.
"Carotid MRI has significant advantages," he said. "The results are more reproducible than those of ultrasound."
Availability and cost effectiveness could limit the use of MRI, Dr. Bluemke cautioned. However, ultrasound and computed tomography (CT) are viable alternatives for screening, he said, especially with improvements in CT dose reduction.
"Carotid Artery Plaque Morphology and Composition in Relation to Incident Cardiovascular Events: The Multi-Ethnic Study of Atherosclerosis (MESA)." Collaborating with Dr. Bluemke were Anna E. H. Zavodni, M.D., Bruce A. Wasserman, M.D., Robyn L. McClelland, Ph.D., Antoinette S. Gomes, M.D., Aaron R. Folsom, M.D., M.P.H., Joseph F. Polak, M.D., M.P.H., and João A. C. Lima, M.D.
Radiology is edited by Herbert Y. Kressel, M.D., Harvard Medical School, Boston, Mass., and owned and published by the Radiological Society of North America, Inc.
RSNA is an association of more than 53,000 radiologists, radiation oncologists, medical physicists and related scientists promoting excellence in patient care and health care delivery through education, research and technologic innovation. The Society is based in Oak Brook, Ill.
For patient-friendly information on MRI, visit RadiologyInfo.org.
Linda Brooks | EurekAlert!
Termination of lethal arrhythmia with light
13.09.2016 | Rheinische Friedrich-Wilhelms-Universität Bonn
Sensor systems identify senior citizens at risk of falling within 3 weeks
29.08.2016 | University of Missouri-Columbia
The Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP has been developing various applications for OLED microdisplays based on organic semiconductors. By integrating the capabilities of an image sensor directly into the microdisplay, eye movements can be recorded by the smart glasses and utilized for guidance and control functions, as one example. The new design will be debuted at Augmented World Expo Europe (AWE) in Berlin at Booth B25, October 18th – 19th.
“Augmented-reality” and “wearables” have become terms we encounter almost daily. Both can make daily life a little simpler and provide valuable assistance for...
With the help of artificial intelligence, chemists from the University of Basel in Switzerland have computed the characteristics of about two million crystals made up of four chemical elements. The researchers were able to identify 90 previously unknown thermodynamically stable crystals that can be regarded as new materials. They report on their findings in the scientific journal Physical Review Letters.
Elpasolite is a glassy, transparent, shiny and soft mineral with a cubic crystal structure. First discovered in El Paso County (Colorado, USA), it can also be...
For the first time, Fraunhofer IKTS shows additively manufactured hardmetal tools at WorldPM 2016 in Hamburg. Mechanical, chemical as well as a high heat resistance and extreme hardness are required from tools that are used in mechanical and automotive engineering or in plastics and building materials industry. Researchers at the Fraunhofer Institute for Ceramic Technologies and Systems IKTS in Dresden managed the production of complex hardmetal tools via 3D printing in a quality that are in no way inferior to conventionally produced high-performance tools.
Fraunhofer IKTS counts decades of proven expertise in the development of hardmetals. To date, reliable cutting, drilling, pressing and stamping tools made of...
At AKL’16, the International Laser Technology Congress held in May this year, interest in the topic of process control was greater than expected. Appropriately, the event was also used to launch the Industry Working Group for Process Control in Laser Material Processing. The group provides a forum for representatives from industry and research to initiate pre-competitive projects and discuss issues such as standards, potential cost savings and feasibility.
In the age of industry 4.0, laser technology is firmly established within manufacturing. A wide variety of laser techniques – from USP ablation and additive...
Every three years, the plastics industry gathers at K, the international trade fair for plastics and rubber in Düsseldorf. The Fraunhofer Institute for Laser Technology ILT will also be attending again and presenting many innovative technologies, such as for joining plastics and metals using ultrashort pulse lasers. From October 19 to 26, you can find the Fraunhofer ILT at the joint Fraunhofer booth SC01 in Hall 7.
K is the world’s largest trade fair for the plastics and rubber industry. As in previous years, the organizers are expecting 3,000 exhibitors and more than...
23.09.2016 | Event News
20.09.2016 | Event News
16.09.2016 | Event News
26.09.2016 | Materials Sciences
26.09.2016 | Materials Sciences
26.09.2016 | Materials Sciences