MR-guided balloon angioplasty of stenosed aorta: in vivo evaluation using near-standard instruments and a passive tracking technique

The purpose of this study was to assess the feasibility of magnetic resonan ce (MR)-guided balloon angioplasty of a stenosed aorta on an open low-field magnet using a passive tracking technique. Visualization of vessels and po sition of instruments were realized by using a fast low-angle shot (FLASH s equence. Catheters and guidewire were prepared for susceptibility-based MR visualization. Standard balloon catheters were inflated with diluted gadoli nium, and nitinol guidewires were modified by incorporation of iron oxide m arkers Into their walls. After validation on a flow phantom, balloon angiop lasty was performed on an in vivo model of arterial stenosis. Creation of a bdominal aorta stenosis was realized in five piglets. AM-guided balloon ang ioplasty of the aorta was performed with success in all but one. in one of them, stent implantation was achieved in the descending aorta. Balloon angi oplasty using a passive tracking technique is a simple concept that can be realized with near-standard Instruments and any MR imaging system. This rep resents an advance toward MR guided vascular interventions in the future. J . Magn. Reson. Imaging 2000; 12:639- 644. (C) 2000 Wiley-Liss, Inc.