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ContextMultidetector computed tomography (MDCT) has been proposed as a noninvasive method to evaluate coronary anatomy.ObjectiveTo determine the diagnostic accuracy of 16-row MDCT for the detection of obstructive coronary disease based exclusively on quantitative analysis and performed in a multicenter study.Design, Setting, and PatientsEleven participating sites prospectively enrolled 238 patients who were clinically referred for nonemergency coronary angiography from June 2004 through March 2005. Following a low-dose MDCT scan to evaluate coronary artery calcium, 187 patients with an Agatston score of less than 600 underwent contrast-enhanced MDCT. Conventional angiography was performed 1 to 14 days after MDCT. Conventional angiographic and MDCT studies were analyzed by independent core laboratories.Main Outcome MeasuresSegment-based and patient-based sensitivities and specificities for the detection of luminal stenosis of more than 50% (of luminal diameter) and more than 70% (of luminal diameter) based on quantitative coronary angiography.ResultsOf 1629 nonstented segments larger than 2 mm in diameter, there were 89 (5.5%) in 59 (32%) of 187 patients with stenosis of more than 50% by conventional angiography. Of the 1629 segments, 71% were evaluable on MDCT. After censoring all nonevaluable segments as positive, the sensitivity for detecting more than 50% luminal stenoses was 89%; specificity, 65%; positive predictive value, 13%; and negative predictive value, 99%. In a patient-based analysis, the sensitivity for detecting patients with at least 1 positive segment was 98%; specificity, 54%; positive predictive value, 50%; and negative predictive value, 99%. After censoring all nonevaluable segments as positive, the sensitivity for detecting more than 70% luminal stenoses was 94%; specificity, 67%; positive predictive value, 6%; and negative predictive value, 99%. In a patient-based analysis, the sensitivity for detecting patients with at least 1 positive segment was 94%; specificity, 51%; positive predictive value, 28%; and negative predictive value, 98%.ConclusionsThe results of this study indicate that MDCT coronary angiography performed with 16-row scanners is limited by a high number of nonevaluable cases and a high false-positive rate. Thus, its routine implementation in clinical practice is not justified. Nevertheless, given its high sensitivity and negative predictive value, 16-row MDCT may be useful in excluding coronary disease in selected patients in whom a false-positive or inconclusive stress test result is suspected.