In vivo assessment of coronary stents with 64-row multidetector computed tomography : Analysis of metal artifacts

Objective: To evaluate stent-induced artifacts by 64-row multi-detector computed tomography (MDCT). Methods: We studied 26 stented patients with MDCT before conventional coronary angiography (CCA). The CT values were measured. Stents were classified as occluded, with significant stenosis, with nonsignificant stenosis, or patent. For the patent stents, mean in-stent and out-stent CT values were compared; stents 3 mm or smaller were compared with stents larger than 3 mm. Multidetector CT was compared with CCA. Results: We analyzed 42 stents. At CCA, 34 stents were patent, 5 were nonsignificantly stenosed, 1 was significantly stenosed, and 2 were occluded. At MDCT, 33 of 34 patent stents, 2 occluded stents, and 1 stent with significant stenosis were correctly diagnosed; nonsignificant stenoses were undetected, 1 patent stent was misdiagnosed as occluded (kappa = 0.727). The out-stent CT value was lower than in-stent CT value both in stents 3 mm or smaller (P = 0.001) and stents larger than 3 mm (P < 0.001). The in-stent CT value of stents 3 mm or smaller was higher (P = 0.011) than that of stents larger than 3 mm. Conclusions: Metal artifacts cause overlooking of nonsignificant stenosis.