Comparing different MR angiography strategies of carotid stents in a vascular flow model: toward stent-specific recommendations in MR follow-up.
BACKGROUND
Carotid artery stenting (CAS) requires adequate follow-up imaging to assess complications such as in-stent stenosis or occlusion. Options include digital subtraction angiography, CT angiography, ultrasound, and MR angiography (MRA), which may offer a non-invasive option for CAS follow-up imaging. The aim of this study was to assess contrast-enhanced MRA (CE-MRA) and three-dimensional time-of-flight MRA (3D-TOF) for visualization of the in-stent lumen in different carotid stents.


METHODS
In this study, we compared CE-MRA and 3D-TOF of five different carotid stents (Guidant Acculink®, Cordis Precise®, Boston Wallstent®, Abbot Vascular Xact®, Cook Zilver®) in three diameters (4, 6, and 8 mm) using a vascular flow model at 3.0 T with the help of a recently developed carotid surface coil. Stent-related artifacts were objectively assessed by calculating artificial lumen narrowing (ALN) and relative in-stent signal (RIS).


RESULTS
RIS and ALN depended heavily on stent type, stent diameter, and the employed MR sequence. ALN and RIS were relatively favorable for Acculink®, Precise®, and Zilver® stents with both CE-MRA and 3D-TOF. CE-MRA provided better results for the Wallstent, while the Xact stent was difficult to visualize with both MRA protocols.


CONCLUSIONS
Both CE-MRA and 3D-TOF are viable options for depicting the in-stent lumen in carotid stents. For specific stents, 3D-TOF provided image quality comparable to CE-MRA and may thus be suitable for in vivo assessment. Development of stent-specific pathways for follow-up imaging seems advisable to address stent-related differences in image quality.
Frölich
Andreas M J
AM
Department of Neuroradiology, University of Göttingen Medical School, Robert-Koch-Str. 40, 37075, Göttingen, Germany. a.froelich@gmail.com
Pilgram-Pastor
Sara M
SM
Psychogios
Marios N
MN
Mohr
Alexander
A
Knauth
Michael
M
D001775:Blood Circulation; D002339:Carotid Arteries / Q000503:physiopathology*; D016893:Carotid Stenosis / Q000628:therapy; D003287:Contrast Media; D005500:Follow-Up Studies; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000145:classification / Q000379:methods*; D008954:Models, Biological; D015607:Stents / Q000145:classification*; D016896:Treatment Outcome
D003287:Contrast Media