MR-velocity mapping in vascular stents to assess peak systolic velocity. In vitro comparison of various stent designs made of Stainless Steel and Nitinol.
BACKGROUND
Peak systolic velocity (PSV) measurements of blood flow inside vascular stents allow reliable detection of in-stent re-stenosis. The purpose of this in vitro study was to evaluate the feasibility of obtaining PSV measurements inside vascular stents made of Stainless Steel and Nitinol, using a velocity encoded MR technique.


METHODS
In a flow phantom, stents of Stainless Steel and Nitinol were studied. The phantom was integrated into a closed-tubing circuit driven by a MR dedicated pulsatile flow pump. MR imaging was performed on a 1.5 T system. The PSV in the tube without stent was used as the gold standard to determine the accuracy and the variability (paired t-test and Pittman's test) of the PSV measurements inside the stents.


RESULTS
PSV values inside the stents showed percentual difference in mean of -15 to 21% (P < 0.05) at a pump setting of 10 and 20 ml/s.


CONCLUSIONS
PSV measurements can be accurately obtained inside stents made of Stainless Steel and Nitinol. MR-velocity measurements may be used in patients to non-invasively evaluate stent patency and in-stent re-stenosis.
van Holten
Jacqueline
J
Department of Radiology, Erasmus MC, University Medical Center Rotterdam, Dr Molewaterplein 40, 3015GD Rotterdam, The Netherlands. vanholten@rond.azr.nl
Kunz
Patrik
P
Mulder
Paul G H
PG
Pattynama
Peter M T
PM
Lamb
Hildo J
HJ
van Dijk
Lukas C
LC
D000497:Alloys; D001158:Arteries / Q000503:physiopathology* / Q000601:surgery*; D001783:Blood Flow Velocity; D019544:Equipment Failure Analysis / Q000295:instrumentation / Q000379:methods*; D005240:Feasibility Studies; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000295:instrumentation / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000295:instrumentation / Q000379:methods; D019047:Phantoms, Imaging; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013193:Stainless Steel; D015607:Stents; D013599:Systole
D000497:Alloys; D013193:Stainless Steel; C013616:nitinol