Carotid Artery MRI helps predict likelihood of strokes and heart attacks

March 4, 2014
This shows a transverse (a) T2-weighted, (b) unenhanced T1-weighted, and (c) gadolinium-enhanced T1-weighted MR images in an 82-year-old man. Pulse sequence parameters are described in Table 1. The left ICA wall shows no plaque or significant wall thickening. The right ICA shows plaque with a lipid core (arrow). ECA = external carotid artery, IJ = internal jugular vein. Credit: Radiological Society of North America

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.

To study the predictive value of MRI plaque imaging, researchers performed 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."

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

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 ."

This diagram shows representative changes in carotid wall area, lumen area, and remodeling index for the ICA and CCA. Representative values of lumen and wall areas are taken from Table 1. The normal remodeling index tends to be approximately 0.4 independent of vessel size. The remodeling index increases with relatively increased atherosclerotic burden. Diagrams are not to scale. Credit: Radiological Society of North America

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.

Explore further: Atherosclerosis in abdominal aorta may signal future heart attack, stroke

More information: "Carotid Artery Plaque Morphology and Composition in Relation to Incident Cardiovascular Events: The Multi-Ethnic Study of Atherosclerosis (MESA)." Radiology, 2014.

Related Stories

Atherosclerosis in abdominal aorta may signal future heart attack, stroke

June 18, 2013
In a study of more than 2,000 adults, researchers found that two MRI measurements of the abdominal aorta—the amount of plaque in the vessel and the thickness of its wall—are associated with future cardiovascular events, ...

High-risk carotid artery plaque formation is increased in older COPD patients

October 26, 2012
Older patients with chronic obstructive pulmonary disease (COPD) are at increased risk for carotid artery plaque formation and for the presence of vulnerable plaques with a lipid core, according to a new study from researchers ...

Increased risk of carotid artery wall thickening in COPD

November 12, 2012
(HealthDay)—For older adults with chronic obstructive pulmonary disease (COPD), the likelihood of carotid artery thickening is increased and vulnerable lipid core plaques are more frequent than in controls with normal lung ...

MRIs could become powerful tools for monitoring cholesteral therapy

October 14, 2011
MRI scanning could become a powerful new tool for assessing how well cholesterol drugs are working, according to Loyola University Health System cardiologist Binh An P. Phan, MD.

Fat around heart may be early indicator of coronary disease

August 16, 2011
Researchers have found more evidence supporting the role of fat around the heart in promoting atherosclerosis, according to a study published online in the journal Radiology.

MRI measure of blood flow over atherosclerotic plaque may detect dangerous plaque

April 5, 2013
Researchers from Boston University School of Medicine (BUSM) have shown that using magnetic resonance imaging (MRI) to measure blood flow over atherosclerotic plaques could help identify plaques at risk for thrombosis. The ...

Recommended for you

Laser device placed on the heart identifies insufficient oxygenation better than other measures

September 20, 2017
A new device can assess in real time whether the body's tissues are receiving enough oxygen and, placed on the heart, can predict cardiac arrest in critically ill heart patients, report researchers at Boston Children's Hospital ...

Metabolism switch signals end for healing hearts

September 19, 2017
Researchers have identified the process that shuts down the human heart's ability to heal itself, and are now searching for a drug to reverse it.

Beta blockers not needed after heart attack if other medications taken

September 18, 2017
A new study from the University of North Carolina at Chapel Hill finds beta blockers are not needed after a heart attack if heart-attack survivors are taking ACE inhibitors and statins. The study is the first to challenge ...

Which single behavior best prevents high blood pressure?

September 15, 2017
(HealthDay)—You probably already know that certain healthy lifestyle behaviors can reduce your risk of developing high blood pressure, but is any one behavior more important than the others?

RESPECT trial shows closing a small hole in heart may protect against recurrent stroke

September 13, 2017
A device used to close a small hole in the heart may benefit certain stroke patients by providing an extra layer of protection for those facing years of ongoing stroke risk, according to the results of a large clinical trial ...

Study shows so-called 'healthy obesity' is harmful to cardiovascular health

September 11, 2017
Clinicians are being warned not to ignore the increased cardiovascular health risks of those who are classed as either 'healthy obese' or deemed to be 'normal weight' but have metabolic abnormalities such as diabetes.

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.