Jma. Meyer et al., MR evaluation of stent patency - In vitro tests of 22 metallic stents and the possibility of determining their patency by MR angiography, INV RADIOL, 35(12), 2000, pp. 739-746
Citations number
23
Categorie Soggetti
Radiology ,Nuclear Medicine & Imaging","Medical Research Diagnosis & Treatment
RATIONALE AND OBJECTIVES. To determine the extent to which visualization of
intrastent anatomy in stents of different composition and design is possib
le by using contrast-enhanced MR angiography.
METHODS. Twenty-two MR-compatible stents, most of which had a diameter of 8
mm, were positioned in a phantom filled with aqueous gadolinium solution.
Coronal and axial spoiled three-dimensional gradient-echo sequences were pe
rformed. Images were acquired with stents positioned at varying angulations
to the main magnetic field B-0. Profiles orthogonal to the stent axis allo
wed measurement of artifact sizes independent of window width and center.
RESULTS. Oriented along B-0, the Cragg, Corvita, Passager, Wallstent, Strec
ker, Impag, Perflex, and ZA stents allowed visualization of more than 48% o
f the lumen. The Memotherm, Smart, and Jostent SelfX stents showed a promin
ent reduction of the inner lumen to below 41%. The lumina of the covered Jo
stent, Palmaz, Sinus, and Symphony stents were completely obscured. The Imp
ag, Perflex, and Strecker tantalum stents shelved growing artifact sizes an
d a lumen reduction of at least 40% with increasing angulation to B-0.
CONCLUSIONS. Evaluation of the inner stent lumen by applying contrast-enhan
ced, three-dimensional gradient-echo sequences is not possible for the majo
rity of stents because of their large artifacts. These depend on the stent
type and orientation to B-0. Even stents made of nitinol and cobalt alloys
only allow qualitative patency assessment but no quantification of stenosis
.