Toroidal Twinax Cable Trap for MRI RF Noise Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing MRI systems face challenges with bulky, expensive, and difficult-to-tune Baluns for reducing stray RF currents in coaxial cables, which are labor-intensive and space-consuming, leading to image errors due to induced currents.
Innovation Solution
A lightweight, flexible RF trap with a conductive system of parallel wires inductively coupled to the shield conductor, forming an LC circuit with capacitive coupling, designed to resonate at RF frequencies, and supported by a torus-shaped structure for effective stray signal attenuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If prior art Baluns are used to reduce stray RF currents, then image quality is improved, but device size and cost increase
Solution Approach 1:
The patent employs a flexible wire structure formed into a toroidal shape that can be collapsed or compressed to a compact size while maintaining its electromagnetic functionality. The wire toroid can be flexed and deformed for storage and installation, then expanded to its functional configuration, effectively reducing the volume occupied by the Balun while preserving its ability to trap stray RF currents and improve image quality.
Solution Approach 2:
The toroidal wire structure is designed to be nested or collapsed into a compact form factor for storage and installation in space-constrained MRI environments. The wire can be coiled or folded within itself, allowing the Balun to occupy minimal space when not in use, while still providing effective RF trapping when deployed.
2Reliability
If prior art Baluns are used to reduce stray RF currents, then image quality is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The Balun is constructed from discrete wire segments that can be easily formed into a toroidal shape using standard fabrication techniques. The wire toroid can be created by bending and joining wire sections, avoiding the need for complex precision manufacturing. This segmented approach simplifies production while maintaining the electromagnetic properties needed for effective RF trapping and image quality improvement.
3Reliability
If Balun circuitry is inserted in-line with coaxial cables, then stray RF currents are reduced, but installation time and labor increase
Solution Approach 1:
The flexible wire toroid can be dynamically deployed and removed as needed. The structure can be expanded to its full toroidal configuration for effective RF trapping during operation, then collapsed or folded for compact storage. This dynamic capability allows for rapid installation and removal without requiring permanent in-line integration with coaxial cables, significantly reducing installation time and labor while maintaining effective stray RF current reduction.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The RF trap effectively reduces stray RF currents and noise, providing a compact, cost-effective solution that minimizes image errors and improves MRI system performance by blocking stray signals, thus enhancing image quality.
Implementation Method 1
a conductive system inductively coupled to the shield conductor of the shielded RF cable
Implementation Method 2
a capacitive coupling between the conductive system and the shield conductor
Implementation Method 3
the capacitive and inductive couplings define an LC circuit with a resonance frequency at a frequency of RF signals carried on the inner conductor
Data Source
AI summary
Various methods and systems are provided for a flexible, lightweight, and low-cost radio frequency (RF) trap for use in a magnetic resonance imaging (MRI) system. In one example, a radio frequency (RF) trap assembly for use in a magnetic resonance imaging (MRI) system is provided, comprising a twinax wire assembly having a plurality of looped portions, each ones of the plurality of looped portions tangentially in contact with a shielded cable, and at least one support structure for substantially maintaining the shape of the plurality of looped portions, the support structure surrounding a portion of the shielded cable, wherein the twinax wire assembly is tuned to a frequency suitable for increasing the impedance of the shielded cable.