Figure 12a. Streak artifacts in a patient who had undergone stent placement 5 years earlier, although the kind of stent is unknown. (a, b) Thin-slab MIP (a) and MPR (b) images show apparent streak artifacts caused by a coronary stent in the left circumflex artery (arrows in a) despite the fact that almost no motion artifacts are seen. Streak artifacts due to very high attenuation contrast material completely obscure the intracoronary lumen. (c) Even on a CT scan obtained with a very wide window setting, only metallic structures can be recognized.