Contrast-enhanced 64-section coronary multidetector CT angiography versus conventional coronary angiography for Stent assessment

Purpose:To prospectively evaluate the accuracy of 64- section computed tomography ( CT) for diagnosis of stent restenosis, by using conventional coronary angiography as the reference standard. Materials and Methods: The ethics committee granted permission for the study; patients gave written consent. Contrast material - enhanced coronary CT angiography was performed in 53 patients ( 45 men, eight women; mean age, 54 years +/- 9 [ standard deviation]) suspected of having stent restenosis. Coronary CT angiographic findings were compared with conventional coronary angiographic findings. Two physicians analyzed coronary CT angiographic data sets with multiplanar reformatted images and three- dimensional reformations by using a volume- rendering technique and looked for stent detectability, low- attenuation in- stent filling defects, and grades of restenosis. Conventional coronary angiographic results were interpreted by one of several observers in consensus for stent restenosis; they were blinded to coronary CT angiographic data. Statistical software and general estimating equations were used for data analysis. Results: One hundred ten stents were identified in 53 patients. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of coronary CT angiography in detection of in- stent restenosis were 96.9%, 88.0%, 77.5%, 98.5%, and 91%, respectively. Coronary CT angiography depicted in- stent low- attenuation filling defects with an accuracy of 91% and negative predictive value of 98.5% ( 95% confidence interval: 90.9, 99.9). Coronary CT angiography depicted the status of 97 of 107 stents. There was no significant difference between in- stent lumen visibility and stent diameter ( P =.104). Coronary CT angiography helped diagnose 15 of 18 stent restenoses with less than 50% narrowing, five of five stent restenoses with 50% - 74% narrowing, and nine of nine ( 100%) stent restenoses with 75% or greater narrowing or total occlusion of the stent lumen. Conclusion: Coronary CT angiography can depict in- stent low- attenuation filling defects, which appear to be a reliable sign of stent restenosis, and 64- section CT depicts such defects with a high degree of accuracy.