What is the role of EBCT in the workup of coronary artery atherosclerosis?

Updated: Apr 09, 2021
  • Author: Sandy N Shah, DO, MBA, FACC, FACP, FACOI; Chief Editor: Yasmine S Ali, MD, MSCI, FACC, FACP  more...
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Answer

Electron beam CT (EBCT) is a relatively new, noninvasive method of evaluating calcium content in the coronary arteries. Healthy coronary arteries lack calcium. As atherosclerotic plaques grow, calcium accumulates because of a perpetuating inflammatory process or the healing and scarring induced by this process. EBCT is currently used as a screening test in asymptomatic patients and as a diagnostic test for obstructive CAD in symptomatic patients, although experts in the field have reached no consensus regarding indications for its use.

EBCT has been demonstrated to have high sensitivity, with an overall predictive accuracy of 70%, according to the American College of Cardiology (ACC)/American Heart Association (AHA) Expert Consensus Document. [41] However, it has low specificity (ie, a substantial false-positive rate), which raises the index of suspicion for CAD and leads to expensive and unwarranted additional testing to exclude CAD. Consequently, the ACC/AHA report did not recommend EBCT scanning to help diagnose obstructive CAD.

Whether EBCT is a worthwhile tool for screening of CAD is still unclear. Well-established clinical indicators, such as the Framingham risk score and the National Cholesterol Education Program (NCEP) risk calculator, already accurately predict the likelihood of CAD. Whether EBCT adds to these indicators has yet to be shown. The Multi-Ethnic Study of Atherosclerosis (MESA), sponsored by the US National Institutes of Health, has been assessing prospective evaluation of EBCT in asymptomatic subjects to answer this question. [42]

EBCT may have niche uses, including (1) determination of whether individuals who appear to be at intermediate risk are really at a higher risk (eg, asymptomatic elderly patients who have high calcium scores) and (2) determination of a low likelihood of significant CAD if EBCT demonstrates a low or absent calcium score.


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