MR-guided balloon angioplasty: In vitro demonstration of the potential of MRI for guiding, monitoring, and evaluating endovascular interventions

The purpose of this study was to demonstrate the potential of MRI for guidi ng, monitoring. and evaluating endovascular interventions, This was done by investigating the feasibility of MR-guided balloon angioplasty in a stenos ed vessel model. Catheters and guidewires were prepared for susceptibility- based MR visualization by incorporating paramagnetic markers into their wal ls. Near real-time monitoring (up to 1 image/see) of the interventional pro cedure was achieved by using a dynamic two-dimensional gradient-echo techni que, Devices were localized by on-the-ny subtraction of a baseline image fr om consecutive dynamic images and by merging the subtraction images with a previously acquired road map. All steps involved in balloon angioplasty, fr om the introduction and placement of a guidewire to the positioning of a ca theter across the stenosis, inflation of the balloon, and dilatation of the stenosis could adequately be monitored with MR fluoroscopy. The beneficial effect of dilatation could be substantiated by a reduction of stenosis-rel ated hypointensities and hyperintensities in the posttreatment MR angiogram as compared to the pretreatment angiogram and by a posttreatment increase of the volumetric now rate.