Theoretical and Experimental Assessment of Radiofrequency Shielding Artifacts of Laser-cut Venous Stents

Motivation: An accurate diagnosis of vein patency is hindered in vein stents by RF shielding artifacts. Some dependencies of RF shielding on stent geometry have been described. Goal(s): Determine a general model for RF shielding prediction in vein stents based on stent geometry. Approach: Field simulations and measurements of the relative induced B1 were performed of stent building blocks (loops, rectangles) and compared to analytical calculations. Results: Separating the RF field into its linearly polarized components, a relationship between RF shielding and loop radius and rectangle dimension could be found, and the shielding could be calculated after component combination. Impact: This work provides a fundamental method to calculate RF-induced shielding from stent geometries. For laser-cut vein stents this information can be used to calculate the optimal excitation flip angle, or to modify the stent geometry to improve the in-stent luminosity.