Next generation coronary CT angiography: in vitro evaluation of 27 coronary stents.

OBJECTIVES: To evaluate in-stent lumen visibility of 27 modern and commonly used coronary stents (16 individual stent types, two stents at six different sizes each) utilising a third-generation dual-source CT system.

METHODS: Stents were implanted in a plastic tube filled with contrast. Examinations were performed parallel to the system's z-axis for all stents (i.e. 0°) and in an orientation of 90° for stents with a diameter of 3.0 mm. Two stents were evaluated in different diameters (2.25 to 4.0 mm). Examinations were acquired with a collimation of 96 × 0.6 mm, tube voltage of 120 kVp with 340 mAs tube current. Evaluation was performed using a medium-soft (Bv40), a medium-sharp (Bv49) and a sharp (Bv59) convolution kernel optimised for vascular imaging.

RESULTS: Mean visible stent lumen of stents with 3.0 mm diameter ranged from 53.3 % (IQR 48.9 - 56.7 %) to 73.9 % (66.7 - 76.7 %), depending on the kernel used at 0°, and was highest at an orientation of 90° with 80.0 % (75.6 - 82.8 %) using the Bv59 kernel, strength 4. Visible stent lumen declined with decreasing stent size.

CONCLUSIONS: Use of third-generation dual-source CT enables stent lumen visibility of up to 80 % in metal stents and 100 % in bioresorbable stents.

KEY POINTS: • Blooming artefacts impair in-stent lumen visibility of coronary stents in CT angiography. • CT enables stent lumen visibility of up to 80 % in metal stents. • Stent lumen visibility varies with stent orientation and size. • CT angiography may be a valid alternative for detecting in-stent restenosis.