Purpose: The evaluation of coronary artery stents is a major limitation of cardiac multislice spiral computed tomography (MSCT). The development of flat-panel detector computed tomography (FPCT) with truly isotropic spatial resolution may overcome this limitation. Thus, we evaluated the use of FPCT in comparison to MSCT for the assessment of coronary artery stents.
Material and methods: Eight different coronary artery stents with a diameter of 3 mm each were placed in a static chest phantom. The phantom was positioned in the CT gantry at angles of 0 degrees , 45 degrees , and 90 degrees toward the z-axis and examined with the prototype of a FPCT (Siemens, Forchheim, Germany) and a commercially available 16-detector row MSCT (Sensation 16, Siemens). Slice thickness was 0.25 mm with FPCT whereas for MSCT, an effective slice thickness of 1 mm with a reconstruction increment of 0.5 mm was used. Image quality was assessed visually using a 5-point grading scale. Stent diameters were measured and compared using a repeated-measures analysis of variance.
Results: When compared with MSCT, artificial lumen reduction was significantly less using FPCT. On average the visible stent lumen was reduced by 16.1% with FPCT, whereas the mean of the lumen reduction was 47.2% with 16-detector row MSCT. Visible lumen diameter as well as image noise significantly increased using FPCT (P < 0.001). With FPCT delineation of the different stent struts became possible.
Conclusion: FPCT proved to be superior when compared with 16-detector row MSCT for the in vitro assessment of coronary artery stents. Improved spatial resolution allows for a detailed assessment of the coronary artery stent lumen.