Coronary magnetic resonance angiography for assessment of the stent lumen: a phantom study.
OBJECTIVE
To evaluate the feasibility of visualizing the stent lumen using coronary magnetic resonance angiography in vitro.


METHODS
Nineteen different coronary stents were implanted in plastic tubes with an inner diameter of 3 mm. The tubes were positioned in a plastic container filled with gel and included in a closed flow circuit (constant flow 18 cm/sec). The magnetic resonance images were obtained with a dual inversion fast spin-echo sequence. For intraluminal stent imaging, subtraction images were calculated from scans with and without flow. Subsequently, intraluminal signal properties were objectively assessed and compared.


RESULTS
As a function of the stent type, various degrees of in-stent signal attenuation were observed. Tantalum stents demonstrated minimal intraluminal signal attenuation. For nitinol stents, the stent lumen could be identified, but the intraluminal signal was markedly reduced. Steel stents resulted in the most pronounced intraluminal signal voids.


CONCLUSIONS
With the present technique, radiofrequency penetration into the stents is strongly influenced by the stent material. Thesefindings may have important implicationsforfuture stent design and stent imaging strategies.
Maintz
David
D
Department of Cardiology and Radiology, Leiden University Medical Center, The Netherlands. maintz@uni-muenster.de
Botnar
Rene M
RM
Fischbach
Roman
R
Heindel
Walter
W
Manning
Warren J
WJ
Stuber
Matthias
M
D019917:Blood Vessel Prosthesis Implantation; D017023:Coronary Angiography / Q000295:instrumentation*; D003324:Coronary Artery Disease / Q000175:diagnosis / Q000601:surgery; D003331:Coronary Vessels / Q000601:surgery*; D004867:Equipment Design / Q000295:instrumentation; D005240:Feasibility Studies; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000295:instrumentation*; D019047:Phantoms, Imaging; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation; D015607:Stents