Coronary artery stent patency assessed with in-stent contrast enhancement measured at multi-detector row CT angiography: initial experience.

The authors investigated the contrast enhancement characteristics of the coronary artery stent lumen to assess patency and then evaluated the accuracy of computed tomographic (CT) measurement of the in-stent luminal diameter. Nineteen patients (16 men and three women; mean age, 58.7 years) with 26 stents underwent cardiac-gated CT angiography with a 16-detector row scanner 1-3 weeks after stent placement. CT images depicted the lumina of 20 stents in 14 patients. CT attenuation measured in the treated lumen was higher than, and correlated highly (r >/= 0.87) with, attenuation in the proximal and distal untreated lumen. Estimated values for in-stent luminal diameter were lower with CT than with conventional angiography (P <.001), and the mean error (16.1%) that resulted from estimation based on sharp-kernel CT images was significantly smaller than that (27.3%) from estimation based on medium-smooth-kernel CT images (P <.001). Visualization of the in-stent lumen at CT angiography with a 16-detector row scanner allows assessment of coronary artery stent patency on the basis of measured contrast enhancement.