MRI guidewire
Inventors
Assignees
US Department of Health and Human Services
Publication Number
US-8478381-B2
Publication Date
2013-07-02
Expiration Date
2028-12-31
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Abstract
A guidewire (100) for use with interventional magnetic resonance imaging has a guidewire body (102) having a distal end and a proximal end and reserving a space therein, a dipole antenna (108) disposed in the space reserved within the guidewire body, the dipole antenna being adapted to be electrically connected to a signal processing system through a first signal channel (110) through the proximal end of the guidewire body, and a loop antenna (112) disposed in the space reserved within the guidewire body toward the distal end of the guidewire body, the loop antenna (112) being adapted to be electrically connected to the signal processing system through a second signal channel (114) through the proximal end of the guidewire body. The dipole antenna and the loop antenna are each constructed to receive magnetic resonance imaging signals independently of each other and to transmit received signals through the first and second signal channels, respectively, to be received by the signal processing system. An interventional magnetic resonance imaging system includes an active guidewire.
Core Innovation
The invention relates to an active guidewire for use with interventional magnetic resonance imaging (iMRI). The guidewire body reserves space for embedding two types of antennas: a dipole antenna and a loop antenna. The dipole antenna is electrically connected to a signal processing system via a first signal channel at the proximal end of the guidewire, and the loop antenna is similarly connected through a second signal channel. Both antennas independently receive magnetic resonance imaging signals and transmit them to the signal processing system.
The guidewire design addresses the challenge of simultaneously visualizing both the shaft and tip of an MRI-compatible guidewire during vascular interventions. Existing visualization methods either rely on passive techniques, which have limitations in spatial resolution and vary based on device orientation, or active techniques, which previously have not provided satisfactory simultaneous visualization of both the tip and shaft. The integration of both a dipole antenna and a loop antenna within the guidewire body enables improved visualization capabilities.
The background emphasizes the importance of reliable visualization of guidewires during MR-guided procedures to prevent vessel wall puncture and to enable precise navigation through complex vessels. The current design incorporates a coaxial arrangement where the dipole antenna favors shaft visualization due to its longitudinal sensitivity, while the loop antenna focuses on tip localization. This configuration overcomes previous shortcomings where susceptibility artifacts or single-point active tracking were insufficient for real-time, safe, and precise instrument guidance under MRI.
Claims Coverage
The patent includes one independent claim which describes an interventional magnetic resonance imaging system with specific features of the active guidewire and its components.
Active guidewire with dual antennas for MRI visualization
An active guidewire incorporating both a dipole antenna and a loop antenna positioned respectively to visualize the shaft and the tip of the guidewire within an MRI system.
Independent signal channels for dipole and loop antennas
Separate first and second signal channels are used to connect the dipole antenna and the loop antenna to a signal processing system, enabling independent reception and transmission of MRI signals from each antenna.
Guidewire body construction with embedded antennas
A guidewire body reserving space for embedding a dipole antenna and a loop antenna, where the dipole antenna is positioned between the proximal end and the loop antenna positioned at the distal end, facilitating visualization of different guidewire portions.
Dipole antenna design using hypotubes
The dipole antenna includes an outer hypotube and an inner hypotube separated by an insulation layer, where the inner hypotube extends beyond the distal end of the outer hypotube to form a whip portion used for MRI signal reception.
Materials and construction details of guidewire antennas
The inner and outer hypotubes of the dipole antenna are made from MRI-compatible materials like Nitinol, with the whip portion having a length suitable for receiving Larmor frequency signals and optionally coated with gold for conductivity.
Loop antenna designs and electrical connections
The loop antenna may be a micro-coil electrically connected via either a micro-coaxial cable or a twisted pair of electrical wires within the space reserved in the guidewire body, forming part of the signal channel system.
Interventional MRI system with display integration
The system includes a signal processing system configured to receive signals from both antennas and a display system capable of showing a real-time image of the active guidewire during surgical procedures.
The patent claims comprehensively cover an interventional MRI system featuring an active guidewire with dual embedded antenna designs dedicated to simultaneous shaft and tip visualization, with independent signal reception channels and specific construction and material features to optimize MRI compatibility and signal processing.
Stated Advantages
The guidewire provides both precise tip location and distal shaft visualization simultaneously during interventional MRI procedures.
The design improves safety and navigation accuracy by allowing clear visualization of the shaft and tip in real-time without compromising mechanical properties.
Using separate antennas with independent signal channels enhances imaging quality and device tracking compared to prior passive or single-antenna active devices.
Documented Applications
Use in vascular interventions requiring MRI guidance where precise visualization of the guidewire tip and shaft is critical.
Integration within interventional magnetic resonance imaging systems for real-time image guidance during surgical procedures.
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