Noninvasive angiographic evaluation of coronary stents with multi-slice spiral computed tomography.
BACKGROUND
The number of patients with obstructive coronary artery disease, who undergo coronary angioplasty with implantation of stents, is ever increasing. As an alternative to catheter-based angiography, ECG-gated multi-slice spiral computed tomography (MSCT) allows noninvasive imaging of the coronary arteries. However, coronary stents have been notoriously difficult to assess by CT.


RESULTS
In vitro experiments were performed, using varying detector collimations, contrast concentrations, stent positions and stent diameters, to evaluate the feasibility and image characteristics of stents. The stent-related high-density artifacts expand the apparent size of the stent struts. This blooming effect is a fairly constant phenomenon, and therefore relatively less evident in larger-diameter stents. The in vivo images show the same artifacts, but assessment is further complicated by motion, lower contrast-to-noise, and vessel wall calcifications.


CONCLUSIONS
The clinical value of CT after percutaneous coronary intervention currently remains largely limited to the detection of stent occlusion, and the progression of coronary artery disease in the remaining nonstented segments. Subtle in-stent abnormalities cannot be reliably imaged. Some relief will be offered by improvements in scanner technology, but the use of less radiopaque stent material would be more effective.
Nieman
Koen
K
Department of Cardiology, Erasmus Medical Center & Thoraxcenter, Rotterdam, The Netherlands. koennieman@hotmail.com
Cademartiri
Filippo
F
Raaijmakers
Rolf
R
Pattynama
Peter
P
de Feyter
Pim
P
D015906:Angioplasty, Balloon, Coronary / Q000295:instrumentation*; D000818:Animals; D016477:Artifacts; D017023:Coronary Angiography; D023903:Coronary Restenosis / Q000000981:diagnostic imaging*; D023921:Coronary Stenosis / Q000000981:diagnostic imaging / Q000628:therapy*; D004867:Equipment Design; D004868:Equipment Failure; D005240:Feasibility Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D066298:In Vitro Techniques; D011856:Radiographic Image Enhancement; D015607:Stents; D036542:Tomography, Spiral Computed