Artifact quantification of venous stents in the MRI environment: Differences between braided and laser-cut designs.

Abstract Purpose To quantify B0- and B1-induced imaging artifacts of braided venous stents and to compare the artifacts to a set of laser-cut stents used in venous interventions. Methods Three prototypes of braided venous stents with different geometries were tested in vitro. B0 field distortion maps were measured via the frequency shift Δ f using multi-echo imaging. B1 distortions were quantified using the double angle method. The relative amplitudes B 1 rel were calculated to compare the intraluminal alteration of B1. Measurements were repeated with the stents in three different orientations: parallel, diagonal and orthogonal to B0. Results At 1.5 T, the braided stents induced a maximum frequency shift of Δ f x 100 H z . Signal voids were limited to a distance of 2 mm to the stent walls at an echo time of 3 ms. No substantial difference in the B0 field distortions was seen between laser-cut and braided venous stents. B 1 rel maps showed strongly varying distortion patterns in the braided stents with the mean intraluminal B 1 rel ranging from 63 ± 18 % in prototype 1 to 98 ± 38 % in prototype 2. Compared to laser-cut stents the braided stents showed a 5 to 9 times higher coefficient of variation of the intraluminal B 1 rel . Conclusion Braided venous stent prototypes allow for MR imaging of the intraluminal area without substantial signal voids due to B0-induced artifacts. Whereas B1 is attenuated homogeneously in laser-cut stents, the B1 distortion in braided stents is more inhomogeneous and shows areas with enhanced amplitude. This could potentially be used in braided stent designs for intraluminal signal amplification.