Stent placement under real-time MR control: First experience in an animal model.

Purpose: The aim of this study was to test the feasibility of iliac artery stent placement under MR guidance with real-time MR radial scanning in an a nimal model. Materials and Methods: The experiments were performed on three pigs in a 1.5 T scanner. Radial scanning with a gradient echo technique (T -R 8.4 ms, T-E 3.6 ms, flip angle 10 degrees) was used. A dedicated backpro jector performed the reconstruction of the raw data in real-time. The resul ting MR-images were displayed on LCD screens beside the magnet. The sliding window reconstruction technique allowed image acquisition at a frame rate of 16 images per second. MR-compatible self-expanding stents with a diamete r of 8 mm and a length of 3 cm were placed into the left iliac artery. Thei r positions were verified by digital subtraction angiography (DSA) and comp ared to MRI. Results: All stents were successfully placed. Stent positions as monitored by real-time MR were identical to those seen on DSA images. Th e time needed for exact positioning of the scan plane ranged from 15 to 30 minutes. Stent placement itself took 8 minutes on average. Conclusion: Radi al scanning applied together with the sliding window reconstruction techniq ue allows placement of stents in iliac arteries under realtime MR control.