Detection of Stent Fractures. A Comparison of 64-slice CT, Conventional Cine-angiography, and Intravascular Ultrasonography

Rational and Objectives: We evaluated the ability of 64-slice computed tomography (CT), conventional cine-angiography, and intravascular ultrasound (IVUS) to detect stent fractures under ideal conditions. Coronary stent fracture has been implicated as one of the mechanisms of stent thrombosis and, perhaps, in-stent restenosis. However, the preferred imaging modality in detecting fractures in coronary stents has not been well established. Materials and Methods: Four different types of commonly used coronary stents (Cypher, Taxus, Vision, Hepacoat) each with three strut fractures (Cypher, 5; Taxus, 5; Vision, 4; Hepacoat, 5) were nominally deployed in polyurethane tubes and imaged with 64-slice CT, conventional cine-angiography, and IVUS. For each stent type, an unfractured control stent was also imaged. Results: Overall accuracy (84.1% vs. 73.9%), sensitivity (80.7 vs. 77.2%), and specificity (100% vs. 58.3%) for stent fracture detection was higher with 64 multislice CT compared to conventional cine-angiography. Stent fractures were not accurately detected by IVUS. Fracture detection by multislice CT was best when the stents were imaged at 45° to the z-axis. Conclusions: Under ideal in vitro conditions, CT has a high accuracy when used to evaluate coronary stent fractures. The overall accuracy, sensitivity, and specificity of detecting stent fractures are lower by conventional cine-angiography. Stent fractures were not detected using IVUS.