Clinical grade active guidewire and catheter for interventional cardiovascular MRI

Abstract

The success and safety of interventional magnetic resonance imaging (MRI) procedures requires conspicuous intravascular instruments that can be distinguished from surrounding tissues. In this dissertation work, an "active" (receiver-coil) clinical grade vascular guidewire and guiding catheter were developed with enhanced visibility and favorable mechanical characteristics for MRI guided cardiovascular interventions. Both 0.035-inch guidewire and 7 Fr guiding catheter were designed combining two different antenna designs on independent channels. The devices incorporate a loop antenna to visualize the tip and determine orientation, and a dipole antenna to visualize the whole guidewire shaft. The MRI visibility performance and RF safety tests were performed at 1.5T in vitro and in vivo in swine. The two channel active guidewire design provided accurate tip position information with 0.97 0.42 mm and novel active shaft visibility technique was introduced to polymer based guiding catheter successfully without sacrificing device size or handling. Mechanical testing comparison with several commercially-available guidewires demonstrated that the new guidewire design provides the desired stiffer distal tip, moderate torquability, and pushability suitable for vascular applications. The RF power threshold and limitations were determined to provide reasonable amount of heating during MRI examination. This may enable a range of interventional procedures using real-time MRI.|Keywords: Interventional Magnetic Resonance Imaging, Active instrument, Equipment Design, Catheterization