MRI may be sufficient for noninvasive assessment of great vessel stents: an in vitro comparison of MRI, CT, and conventional angiography.
OBJECTIVE
The purpose of this study was to compare the diagnostic performance of MRI and CT assessment of great vessel stents in an in vitro model.


METHODS
Three contemporary great vessel stent materials (nitinol, platinum-iridium, and stainless steel) were assessed with three luminal conditions: no stenosis, internal stenosis, and external stenosis. Stents of the same material were implanted into an aorta model that was attached to an animal bypass pump with pulsatile flow. Each stent was imaged with conventional angiography as reference standard, 10 different MRI sequences, and CT. The sensitivity and specificity for the identification of stent stenosis was determined and stent lumen measurements compared.


RESULTS
Of the investigated MRI sequences, three had the highest overall sensitivity and specificity for the identification of stent stenosis in all studied materials: through-plane gradientrecalled echo (GRE) with 75° flip angle (100% and 95%, respectively), in- and through-plane steady-state free precession (SSFP) (99% and 90%) and MR angiography (MRA) with 75° flip angle (93% and 85%). Comparable sensitivity and specificity were achieved with CT (98% and 93%). GRE, SSFP, and MRA sequences tended to underestimate stent lumen diameter in externally nonstenosed stents and overestimate diameter in internally stenosed stents (p < 0.05). CT slightly underestimated external stenoses in all stent types (p < 0.05).


CONCLUSIONS
Defined MRI sequences are feasible to assess nitinol, platinum-iridium, and stainless steel great vessel stents with diagnostic performance comparable with CT.
Nordmeyer
Johannes
J
Cardiorespiratory Unit, Great Ormond Street Hospital for Children, NHS Trust, London WC1N 3JH, United Kingdom.
Gaudin
Régis
R
Tann
Oliver R
OR
Lurz
Phillip C
PC
Bonhoeffer
Phillip
P
Taylor
Andrew M
AM
Muthurangu
Vivek
V
D000792:Angiography / Q000379:methods*; D000818:Animals; D001011:Aorta; D066298:In Vitro Techniques; D008279:Magnetic Resonance Imaging; D012680:Sensitivity and Specificity; D015607:Stents; D013552:Swine; D014057:Tomography, X-Ray Computed