Subspecialty Clinics: Cardiology
Electron Beam Computed Tomography and Coronary Artery Disease: Scanning for Coronary Artery Calcification

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Objective

To review the association of coronary artery calcification with coronary atherosclerosis and its potential clinical application as detected on electron beam computed tomography (EBCT).

Design

A literature review of coronary artery calcification, coronary artery disease, and EBCT is presented, and clinical applications of EBCT are discussed.

Results

Recent studies have confirmed that arterial calcification is an active process intimately associated with atherosclerotic plaque evolution. Clinical investigations with use of EBCT have shown that a scan “negative” for coronary calcification is common in patients with normal or near-normal findings on coronary angiography, whereas patients with severe obstructive disease most commonly have “positive” scans&x2014;greater amounts of coronary artery calcium are associated with more severe luminal disease. Coronary artery calcium as evaluated on EBCT follows patterns that reflect the development of coronary atheromatous disease as a function of age and gender. Although histologic studies have confirmed that not all atherosclerotic segments have detectable calcification, the area of coronary artery calcification quantified on EBCT has a direct, positive relationship with the histopathologic coronary plaque area.

Conclusion

The long-held notion of “degenerative” calcification of the coronary arteries with aging is incorrect. Although the incidence of coronary artery calcification increases with patient age, this relationship simply parallels the increased incidence of coronary atherosclerosis with advancing age. Data suggest that EBCT is a highly sensitive and specific test for coronary atherosclerosis and provide a basis for clinical applications when EBCT is viewed as a noninvasive method to estimate human coronary atherosclerotic involvement and “plaque bur&x00AD;den.”

Section snippets

Pathophysiologic Mechanisms Of Calcification And Atherosclerotic Disease

Calcification of the coronary arteries is actually calcium phosphate in the form of hydroxyapatite, which also is the major inorganic component of bone. Although the role of calcification in coronary artery disease is unclear, recent data demonstrate its pathophysiologic mechanisms. Fitzpatrick and associates8 used special staining techniques to examine coronary artery specimens obtained at autopsy and found that mural mineralization was present to some extent and diffuse in virtually all

Electron Beam Computed Tomography

With conventional CT, a single x-ray source mechanically rotates around the patient in concert with a stationary or rotating collimator-detector combination. Scan speeds of 1 to 2 seconds for conventional scanners and even 600 ms for the new spiral technology are still too slow to capture cardiac motion or evaluate fine details of cardiac and coronary anatomy. EBCT (introduced commercially in 1983) employs a stationary source-detector pair coupled to a unique technology whereby x-rays are

Coronary Artery Calcification, Coronary Artery Disease, And Ebct

Tanenbaum and coworkers13, 14 described EBCT detection of coronary artery calcium in 54 patients undergoing clinically indicated coronary angiography. In 11 patients with no angiographically detectable coronary artery disease, none had detectable calcium on EBCT (“negative” test results). Conversely, discrete coronary artery calcium was detected by EBCT in 88&x0025; of patients who had at least one hemodynamically significant coronary artery lesion (defined as greater than 70&x0025; diameter

Age, Gender, Atherosclerotic Plaque, And Coronary Artery Calcification

Janowitz and colleagues21 have published the most extensive investigation to date on the prevalence and extent of coronary artery calcium detected by EBCT. This study was conducted in 1,898 men and women, whose ages ranged from 20 to older than 80 years (Fig. 2). The pertinent points about these data are as follows. First, regardless of gender, the prevalence of coronary artery calcium increases with advancing age. Second, the prevalence of coronary calcium is lower in women than in men until

Clinical Applications And Interpretation

A relationship between the fluoroscopic presence of coro&x00AD;nary artery calcification and cardiovascular prognosis has been suggested. Detrano and associates26 recently described the clinical significance of digital fluoroscopic examination for coronary artery calcium in a prospective assessment of 1,461 asymptomatic adults older than 45 years of age who were at high risk for coronary disease (Framingham risk calculation, 10&x0025; or higher over 8 years). At 1-year follow&x00AD;-up, 53

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  • Cited by (0)

    This study was supported in part by Grants HL 46292 and HL 51736 from the National Institutes of Health, Public Health Service, and by Mayo Foundation. Dr. Rumberger is supported in part by an Established Investigator Award from the American Heart Association.

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