Impact of calcification on diagnostic accuracy of 64-slice spiral computed tomography for detecting coronary artery disease: a single center experience.

BACKGROUND: The main aim of our study was to investigate the influence of calcification on the accuracy of 64-slice computed tomography for identification of significant coronary artery disease. METHODS: A contrast-enhanced 64-slice computed tomography was performed prior to invasive coronary angiography in 168 consecutive patients with suspected coronary artery disease. All coronary segments 1.5 mm or larger in diameter were evaluated for the presence or absence of significant coronary artery stenosis, defined as a diameter reduction of >50%. The patients were also ranked by total calcium score which was expressed in Agatston units and the impacts of calcification on diagnostic accuracy of 64-slice computed tomography were assessed. Results were compared with quantitative coronary angiography as the standard of reference. RESULTS: The overall sensitivity, specificity, positive predictive value, and negative predictive value of 64-slice computed tomography for detection of significant stenosis were: by segments, 95%, 98%, 91%, and 99%, respectively; by patient, 98%, 97%, 96%, and 99%, respectively; and by artery, 94%, 93%, 91%, and 95%, respectively. In mild and moderate calcium scores (0-418 Agatston units), the sensitivity was 100%, specificity was 93%, positive predictive value was 97% and negative predictive value was 100%. Severe calcification (>419 Agatston units) reduced the sensitivity, specificity, positive, and negative predictive values of multi-slice computed tomography to 89%, 60%, 89%, and 60%, respectively. CONCLUSION: Our study revealed that the 64-slice computed tomography is a highly accurate diagnostic modality for detecting hemodynamically significant coronary stenosis; however, severe calcification is considered as a shortcoming which limits the routine application of multi-slice computed tomography in daily practice.