Electron-Beam Computed Tomography

Electron-Beam Computed Tomography
(EBCT or helical or fast CT for determining cardiac calcification)

Coronary artery disease is the leading cause of death in the United States. Most people who die as a result of a myocardial infarct (heart attack) have no previous symptoms or warnings. Physicians have traditionally relied upon predictive cardiac tests such as stress tests (e.g., treadmill tests) to evaluate and diagnose patients. These tests, according to experts at the American College of Cardiology, have "a couple of drawbacks…treadmill tests are limited to patients who have normal electrocardiograms at rest and still have the capacity to exercise, and they miss about 10 to 20 percent of cases." ¹

Alternative Diagnostic Methods Can Save Lives. EBCT scans, an alternative to older cardiac diagnostic tests, are non-invasive CT scans of the heart that can detect and quantify calcium deposits in coronary arteries. A coronary calcium score derived from EBCT scans is, according to the American Heart Association, known to predict the occurrence of cardiac events, such as fatal and nonfatal heart attacks or the need for coronary bypass surgery or angioplasty over the next year or two.

In fact, researchers have found that, for certain subsets of patients, EBCT is a superior diagnostic method. A July 1, 2000 American College of Cardiology news release, entitled Electron-Beam Computed Tomography Proves Superior to Alternative Diagnostic Methods, stated that

…researchers have discovered that an imaging technique called EBCT represents an accurate, rapid alternative to traditional stress testing. EBCT is a noninvasive method for detecting calcium deposits in the coronary arteries, a harbinger of the hardening of the arteries known as atherosclerosis. In the study, 97 patients underwent treadmill testing, nuclear imaging, and EBCT within three months of coronary angiography or evaluation for chest pain. The researchers found that EBCT did a better job at diagnosing coronary artery disease than the other two methods.

While the predictive ability of EBCT is not of value to patients who have already suffered a heart attack or undergone coronary bypass surgery or coronary angioplasty, a group of experts from the American College of Cardiology and the American Heart Association reached consensus on this diagnostic technology, noting, that "a positive calcium score might be valuable in determining whether a patient who appears to be at intermediate risk is actually at high risk. Conversely, a low or absent EBCT calcium score may also prove useful in determining a low likelihood of developing heart disease."

In addition, the American Heart Association, has noted that EBCT is an especially fast form of X-ray imaging technology that is particularly useful in:

• Evaluating bypass graft patency, intra and congenital cardiac lesions, and

• Quantifying right and left ventricular muscle mass, chamber volumes, and systolic and diastolic function (such as cardiac output and ejection fraction).