Vulnerable carotid plaque on MRI helps predict cardiovascular events

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 - carotid plaque
Low-signal-intensity calcium (arrow) and lipid core (arrowheads) can be seen on T1-weighted MR images obtained superior to the carotid artery bifurcation.
Source: Radiology 2014;271:381-389

In asymptomatic subjects at risk for cardiovascular events, identification of vulnerable plaque characteristics with MRI could offer a major assist in cardiovascular disease prediction, according to a study published in the May issue of Radiology.

Imaging features of particular interest included remodeling of the carotid artery wall and identification of plaque composition, explained lead author Anna E. H. Zavodni, MD, of Sunnybrook Health Sciences Centre, University of Toronto, and colleagues.

“The combination of MR imaging remodeling index and presence of lipid core resulted in improvement of the net reclassification index compared with traditional risk factors for cardiovascular disease events,” they wrote.

Findings were based on an evaluation of 946 participants in the Multi-Ethnic Study of Atherosclerosis (MESA). All subjects underwent MRI to define carotid plaque composition and remodeling index, and ultrasound to assess carotid wall thickness. Incident cardiovascular events were tracked for an average of 5.5 years.

A total of 59 participants (6 percent) experienced a cardiovascular event. Carotid ultrasonographic intima-media thickness and MR imaging remodeling index, lipid core and calcium in the internal carotid artery were all significant predictors of events.

“Since cerebrovascular disease was not a common event in this study, we conclude that the lipid core enabled identification of a ‘vulnerable patient’ rather than a vulnerable plaque,” wrote Zavodni and colleagues. “Indeed, about 16 percent more subjects with events and 7 percent of subjects without events were correctly reclassified compared with traditional risk factors when both the carotid remodeling index and the lipid core were used for risk stratification.”

The authors suggested their results bolster the case for the use of MRI features to predict cardiovascular endpoints and be used as a surrogate marker of efficacy in therapeutic studies.