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 increasingl y advocated as a diagnostic test for coronary artery disease (CAD). Before its clinical use is justified, however, the overall accuracy of EBCT must b e better defined. Objective: To estimate the accuracy of EBCT in diagnosing obstructive CAD. Data Sources: English-language studies from January 1, 1979, through Febura ry 29, 2000. were retrieved using MEDLINE and Current Contents databases, b ibliographies, and expert consultation. Study Selection: We included a study if it (1) used EBCT as a diagnostic te st; (2) reported cases in absolute numbers of true-positive, false-positive . true-negative, and false-negative results, and (3) used coronary angiogra phy as the reference standard for diagnosing obstructive CAD (defined as gr eater than or equal to 50% diameter stenosis). Data Extraction: Data were extracted from the in eluded articles by 2 indep endent reviewers. Data Synthesis: Weighted pooled analysis and summary receiver operating cha racteristic (ROC) curve analysis were used to determine sensitivity and spe cificity rates. Results from 9 studies with 1662 subjects were included. Po oled 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 specif icity changed. For a threshold that resulted in a sensitivity of 90%, speci ficity was 54%; when sensitivity was 80%, specificity rose to 71%. Conclusion: The performance of EBCT as a diagnostic test for obstructive CA D is reasonable based on sensitivity and specificity rates from its summary ROC curve.