New concepts and materials for the manufacturing of MR-compatible guide wires

Abstract

This paper shows the development of a new magnetic resonance imaging (MRI)-compatible guide wire made from fiber-reinforced plastics. The basic material of the developed guide wire is manufactured using a specially developed micro-pullwinding technology, which allows the adjustment of tensile, bending, and torsional stiffness independent from each other. Additionally, the micro-pullwinding technology provides the possibility to vary the stiffness along the length of the guide wire in a continuous process. With the possibilities of this technology, the mechanical properties of the guide wire were precisely adjusted for the intended usage in MRI-guided interventions. The performance of the guide wire regarding the mechanical properties was investigated. It could be shown, that the mechanical properties could be changed independently from each other by varying the process parameters. Especially, the torsional stiffness could be significantly improved with only a minor influence on bending and tensile properties. The precise influence of the variation of the winding angle on the mechanical and geometrical properties has to be further investigated. The usability of the guide wire as well as its visibility in MRI was investigated by radiologists. With the micro-pullwinding technology, a continuous manufacturing technique for highly stressable, MRI-safe profiles is available and can be the trigger for a new class of medical devices.

Right heart catheterization using metallic guidewires and low SAR cardiovascular magnetic resonance fluoroscopy at 1.5 Tesla: first in human experience

“…Until now, metallic guidewires, an important adjunct for X-ray fluoroscopy catheterization, have not been used during CMR fluoroscopy catheterization out of concern that long conductive structures will heat by coupling electrically with radiofrequency (RF) excitation pulses [ 7 , 8 ]. Glass and other non-metallic guidewires have been reported for CMR catheterization but suffer insurmountable fragility that will likely preclude wide adoption [ 9 – 12 ]. Non-conductive metallic guidewires have been reported that resist heating during CMR but that are not yet commercially available [ 13 ].…”

X-ray to MR: the progress of flexible instruments for endovascular navigation

“…The consolidated fibre/resin is then passed through a cooling device to ensure a dimensionally stable end product [130]. In attempt to manufacture guidewires with different mechanical properties along its length, the Fraunhofer IPT team developed the micro-pullwinding process [129], a process combining both pultrusion and filament winding. In this process, the pultruded profile (using glass fibres) is wrapped and consolidated with additional layers of high-strength synthetic fibres (e.g.…”

“…In this process, the pultruded profile (using glass fibres) is wrapped and consolidated with additional layers of high-strength synthetic fibres (e.g. Kevlar®) in several winding units to significantly enhance its torsional and radial stiffness (figures 11(f)-(i)) [129]. Moreover, since glass fibres are susceptible to buckling, the The core is grounded at its distal end to create a flexible distal end.…”

“…Passive negative markers are applied at discrete intervals for MR visibility and an outer layer is utilised to form the guidewire. (h) Flexible tip achieved by small winding pitch and (i) High bending and torsional stiffness of guidewire shaft achieved by large winding pitch [129].…”

Patient customized engineering for smart cardiovascular therapy

“…Up until now, catheters and guide wires have only been suitable for use under fluoroscopy. The project "MiGi" aims to close this gap [1]. The development of a novel guide wire should facilitate the application of alternative imaging techniques (MRI and ultrasound) during medical interventions.…”