Radiopacity of current endovascular stents: evaluation in a multiple reader phantom study.
OBJECTIVE
To evaluate the radiopacity of endovascular stents based on the fluoroscopy mode in a phantom of the human pelvis.


METHODS
The following stents were included in this study: Medtronic AVE Bridge, Medtronic AVE Bridge X, Cordis Covered Nitinol (Covent), Guidant Dynalink, Luminexx, Guidant Megalink, Memotherm Flexx, Palmaz Medium, Palmaz-Schatz Long-Medium, Palmaz Corinthian PQ394Q and PQ294Q, SelfX, SMART without markers, SMART with radiopaque markers, Easy Wallstent. To evaluate radiopacity, images of the stents placed in four different positions (lumbosacral junction left and right, iliosacral joint left and right) of a pelvic phantom were taken at the following modes: spotfilm, continuous fluoroscopy, 15 pulses per second, 7.5 pulses per second, and 3 pulses per second. Images were presented at random to four independent readers and radiopacity scores were assessed: 0 = not visible, 1 = poor visibility, 2 = average visibility, 3 = good visibility, and 4 = very good visibility.


RESULTS
The Covent stent had the highest overall radiopacity score (3.25), followed by the Luminexx (3.04) and the Medtronic AVE Bridge X (2.74) stents. At the spotfilm mode, the best visible stents were the Medtronic AVE Bridge X, the Covent and the Easy Wallstent stents and at the continuous fluoroscopy mode, the Covent, the Luminexx, and the Medtronic AVE Bridge X stents. Decreasing the fluoroscopy mode went hand in hand with a reduction of the radiopacity scores of all stents. At the standard fluoroscopy mode of 7.5 pulses per second, the Covent stent was seen well or very well in 96.9%, followed by the Luminexx (76.9%), and the Medtronic AVE Bridge X (41.25%) stents.


CONCLUSIONS
Stent radiopacity directly depends on the fluoroscopy mode; if the pulse frequency decreased, detecting the stents became more difficult. Stent mass correlates with stent radiopacity (e.g., Cordis Covered Nitinol, Bridge X). Radiopaque markers may improve stent radiopacity dramatically (e.g., Luminexx vs Memotherm Flexx).
Wiskirchen
Jakub
J
Department of Diagnostic Radiology, University of Tübingen, Germany. jakub.wiskirchen@med.uni-tuebingen.de
Kraemer
Karin
K
König
Claudius
C
Kramer
Ulrich
U
Trübenbach
Jochen
J
Wersebe
Annika
A
Tepe
Gunnar
G
Dietz
Klaus
K
Claussen
Claus D
CD
Duda
Stephan H
SH
D019917:Blood Vessel Prosthesis Implantation / Q000706:statistics & numerical data; D004867:Equipment Design; D019544:Equipment Failure Analysis / Q000706:statistics & numerical data; D005471:Fluoroscopy; D006801:Humans; D015588:Observer Variation; D010388:Pelvis / Q000000981:diagnostic imaging / Q000601:surgery; D019047:Phantoms, Imaging; D015607:Stents / Q000706:statistics & numerical data