In patients presenting to the emergency department (ED) with intermediate-risk chest pain, adenosine stress cardiac MR imaging performed within 12 hours of presentation is safe and could have better performance characteristics than stress echocardiography, according to a study published online Dec. 10 by Radiology.

It’s estimated that over 8 million patients present to the ED per year with chest pain. These patients require difficult examinations focused on identifying those at increased risk for future cardiac events because of underlying coronary artery disease (CAD). While electrocardiographic changes and serial assessment of cardiac biomarkers are valuable for this patient group, about 50 percent of patients with acute coronary syndromes have normal electrocardiograms at initial imaging.

Though stress echocardiography is an established method used to detect CAD, a multicomponent cardiac MR examination that includes adenosine stress perfusion imaging was recently proven to provide accurate diagnosis of CAD in many clinical settings. “However,” wrote the study’s lead author, John F. Heitner, MD, of Duke University Medical Center in Durham, N.C., “data concerning the value of stress cardiac MR imaging in patients seen in the ED is limited, particularly in comparison with other stress modalities and in the early hours after presentation.”

Heitner and colleagues designed a prospective study to compare the utility and efficacy of stress cardiac MRI with that of echocardiography in an emergency setting in patients with acute chest pain and intermediate risk of CAD. Sixty patients without history of CAD presented to the ED with intermediate-risk acute chest pain and were enrolled. Patients underwent both stress cardiac MRI and stress echocardiography in random order within 12 hours of presentation. Stress imaging results were immediately clinically interpreted and coronary angiography was performed if either result was abnormal.

The study’s results revealed that stress cardiac MRI and stress echocardiography had similar specificity, accuracy, and positive predictive values. Stress cardiac MRI had higher sensitivity at clinical interpretation, which did not reach significance at blinded interpretation. Ultimately, multivariable logistic regression analysis showed stress cardiac MRI to be the strongest independent predictor of significant CAD.

“The results of this study support the feasibility, safety, and accuracy of stress perfusion cardiac MR imaging in the ED,” wrote Heitner and colleagues. “In addition, stress cardiac MR imaging showed added value over traditional clinical indexes used for ED triage and had performance characteristics at least as good as those of stress echocardiography. The potential for improvement in test sensitivity over that provided by stress echocardiography will require further evaluation in a larger population.”