Three-dimensional MR angiography of a nitinol-based abdominal aortic stent graft: assessment of heating and imaging characteristics

Objective: To assess heating- and 3D MRA characteristics of a commonly used aortic stent graft in a 1.5T MR-environment. Materials and methods: A bifurcated stent graft (Vanguard; Boston Oakland, N.J.) was evaluated in vitro regarding localized heating effects as well as imaging appearance using fast 3D GRE sequences. To quantitate stent related artifacts, stent wall thickness and luminal diameters were measured. Subsequently eight patients were imaged three months following placement of an aortic stentgraft with 3D MRA. Images were assessed for the presence of stent leaks, luminal patency, and stent configuration. Results: There were no temperature changes associated with the stent during scanning. Wall thickness measurements overestimated true stent thickness, resulting in minimal underestimation of luminal diameters on 3D MRA images. In vivo imaging confirmed these results. Stent patency was confirmed in all 8 patients. Conclusion: Contrast-enhanced 3D MRA appears well suited for the evaluation of the abdominal and pelvic vasculature following aortic implantation of a Vanguard stent.