How MRI Can Provide CVD Risk Assessment

Measuring common carotid artery (CCA) wall thickness using MR imaging improves cardiovascular disease risk assessment among patients with no known risk factors, according to a study published in the journal Radiology.

Researchers from Maryland, New York, Wisconsin, Massachusetts, and California performed a prospective study to compare CCA measured manually by ultrasound and semiautomatically with MR imaging, and to examine their associations with incident coronary heart disease and stroke.

“The carotid artery serves as window into the cardiovascular system,” lead author Bruce A. Wasserman, MD, from Johns Hopkins University School of Medicine in Baltimore, said in a release. “Plaque developing in the carotid artery can contribute directly to a stroke, and its features-which determine its vulnerability to rupture-are closely related to those found in coronary artery plaque in the same patients.”

A total of 698 subjects with no history of clinical cardiovascular disease (CVD) participated in the trial. The mean age for men was 63.2 years and for women, 63.7 years; 55.4% of the subjects were men. All subjects underwent ultrasound and noncontrast proton-density–weighted and IV gadolinium-enhanced MRI.

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The results showed the adjusted hazard ratios for coronary heart disease, stroke, and CVD associated with per standard deviation increase in intima-media thickness were 1.10, 1.08, and 1.14, respectively. The corresponding associations for mean wall thickness measured with proton-density–weighted MRI were 1.32, 1.48, and 1.37; and for mean wall thickness measured with gadolinium-enhanced MRI were 1.27, 1.58, and 1.38. When included simultaneously in the same model, MRI wall thickness, but not intima-media thickness, remained associated with outcomes.

“What we saw was surprising,” Wasserman says. “MRI measures of carotid artery wall thickness were more consistently associated with cardiovascular events than was intima-media thickness using ultrasound. This tells us that perhaps MRI could be a better predictor of cardiovascular events, especially stroke.”

Wasserman cautioned that more research is needed to define how much MRI can add to the predictive models currently in use. “We’ve come a long way with MRI techniques and their ability to discriminate the carotid artery wall and assess adventitia thickness,” he says. “Ultrasound has also improved, and we want to be able study cardiovascular risk and carotid artery thickness using these contemporary techniques.”