Stent lumen visualization

Fig. 16.2a,b. In-stent lumen imaging, a Imaging of a stent phantom acquired on a conventional 16-detector-row scanner with a voxel size of 1 mm. A conventional cobalt-chromium alloy bare metal stent (Multi-Link Vision Rx Coronary Stent System, Boston Scientific, Gatwick, Mass.) with thin struts (0.08 mm) is used, b The same stent as in a is visualized with a fourfold-better spatial resolution (voxel size of 0.25 mm), utilizing a flat-panel detector. (Modified according to Mahnken et al. 2005)... 

Fig. 17.2. The influence of the stent size and the window settings on stent Imiien visualization. A 58-year-old patient with status post implantation of three stents in the left anterior descending coronary artery. A volmiie-rendered image (left) nicely shows the location of the first stent distal to the first diagonal branch and the other two stents distal of the second diagonal branch. On the right, curved MPR through the left anterior descending coronary artery are shown, with six different window settings. The wider the window, the better visible is the stent Imiien. With a window width of 400 and a window center of 160 the stent Imiien is not visible at all window settings of 1,500/300 are recommended. Note also the influence of the stent diameter on the lumen visibility. While the lumen of the proximal stent with a diameter of approx. 3.5 mm is nicely assessable, the most distal stent with a diameter of 2 mm is not evaluable...

When using 3D C-arm imaging for the visualization of stents, physicians again found that access to 3D information during the intervention facilitated better clinical outcomes (Van Den Berg et al. 2002 Benndorf et al. 2005, 2006 Richter et al. 2007a). Benndorf et al, for example, valued the clear visualization of both the stent struts and their adaptation to arterial walls and aneurismal lumen. 

The deconvolution (or simply subtraction) of images adjacent to the K-edge of the contrast agent of interest allows visualization the lumen, without any overly. This concept has first been shown in simulation studies and subsequently been realized on a prototype scanner. First clinical proof-of-concept papers have shown the feasibility to separate gadolinium from stent struts and calcium in phantom studies (Feuerlein et al. 2008). 

---