Electron-beam computed tomography in the diagnosis of coronary artery disease: a meta-analysis.

BACKGROUND: Electron-beam computed tomography (EBCT) is a new, noninvasive method of detecting coronary artery calcification that is being increasingly advocated as a diagnostic test for coronary artery disease (CAD). Before its clinical use is justified, however, the overall accuracy of EBCT must be better defined.
OBJECTIVE: To estimate the accuracy of EBCT in diagnosing obstructive CAD. DATA SOURCES: English-language studies from January 1, 1979, through February 29, 2000, were retrieved using MEDLINE and Current Contents databases, bibliographies, and expert consultation. STUDY SELECTION: We included a study if it (1) used EBCT as a diagnostic test; (2) reported cases in absolute numbers of true-positive, false-positive, true-negative, and false-negative results; and (3) used coronary angiography as the reference standard for diagnosing obstructive CAD (defined as > or = 50% diameter stenosis). DATA EXTRACTION: Data were extracted from the included articles by 2 independent reviewers. DATA SYNTHESIS: Weighted pooled analysis and summary receiver operating characteristic (ROC) curve analysis were used to determine sensitivity and specificity rates. Results from 9 studies with 1662 subjects were included. Pooled sensitivity for EBCT was 92.3% (95% confidence interval [CI], 90.7%-94.0%) and pooled specificity was 51.2% (95% CI, 47.5%-54.9%). Maximum joint sensitivity and specificity for EBCT from its summary ROC curve was 75%. As the threshold for defining an abnormal test varied, sensitivity and specificity changed. For a threshold that resulted in a sensitivity of 90%, specificity was 54%; when sensitivity was 80%, specificity rose to 71%.
CONCLUSION: The performance of EBCT as a diagnostic test for obstructive CAD is reasonable based on sensitivity and specificity rates from its summary ROC curve.