MRI Gradient Coil Hollow Wire Segmentation
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Solution Overview
Problem
Magnetic resonance imaging (MRI) systems face high operational costs due to electrical resistance in gradient coils, which is exacerbated by eddy currents in other components, and existing solutions like hollow copper conductors are expensive to manufacture.
Innovation Solution
The use of a hollow conducting wire with a body defining a passageway and multiple conductors disposed within, which reduces eddy currents and electrical resistance by distributing the current through multiple smaller conductors, similar in cross-sectional area to traditional solid conductors, and allows for improved cooling and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional solid copper conductors are used in gradient coils, then electrical resistance is reduced, but eddy currents are generated in other components increasing overall resistance and power consumption
Solution Approach 1:
The patent applies segmentation by dividing the current path into multiple smaller conductors (e.g., 10-100 individual wires) bundled together to form the gradient coil windings. This segmentation reduces the cross-sectional area of each individual conductor, which in turn reduces the magnitude of eddy currents generated in surrounding components while maintaining the same total current-carrying capacity and reducing overall electrical resistance through parallel conduction paths
2Loss of energy
If hollow copper conductors are used to reduce eddy currents, then power consumption is reduced, but manufacturing cost increases significantly
Solution Approach 1:
The patent replaces expensive hollow copper conductors with inexpensive solid copper wires that are segmented into multiple smaller conductors. These standard solid copper wires are much cheaper to manufacture while achieving the same energy efficiency benefits through the segmented configuration, effectively substituting a costly specialized component with inexpensive standard components arranged in a specific configuration
Solution Approach 2:
The patent creates a composite conductor structure by bundling multiple individual copper wires together with insulation and support elements. This composite construction combines the advantages of multiple thin conductors (reduced eddy currents) with the simplicity and low cost of standard solid copper wiring, achieving both energy efficiency and manufacturing ease
3Object-generated harmful factors
If multiple smaller conductors are used instead of solid conductors, then eddy currents are reduced, but device complexity increases
Solution Approach 1:
The patent makes the multi-conductor structure multi-functional by having it simultaneously serve as the current-carrying gradient coil windings, the structural framework for coil winding, and the cooling channel pathway. The support structure holding the multiple conductors in place also functions as the cooling channel, eliminating the need for separate cooling system components and reducing overall device complexity despite the increased number of conductors
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
This approach reduces the power required to drive gradient coils, lowers operational costs, and maintains the same imaging performance as traditional systems while being more cost-effective and flexible.
Implementation Method 1
Generation of a magnetic field by a gradient coil, however, results in electrical resistance within the electrical wires of the gradient coil. The generation of a magnetic field by a gradient coil may also produce eddy currents within other components of an MRI system
Implementation Method 2
The amount of electrical resistance within the electrical wires of a gradient coil partially determines the amount of electrical power required to drive the gradient coil
Implementation Method 3
Many gradient coils are driven by electrical wires wrapped into coils. As used herein with respect to gradient coils, the terms 'driven' and 'drive' refer to the generation of a magnetic field resulting from the flow of electrical current through the electrical wires of the gradient coil
Implementation Method 4
The nuclei are excited by a radio frequency ('RF') signal/pulse transmitted by a RF coil at characteristics NMR (Larmor) frequencies. By spatially disturbing localized magnetic fields surrounding the subject and analyzing the resulting RF responses from the nuclei as the excited protons relax back to their lower energy normal state
Data Source
AI summary
An MRI system for imaging a subject is provided. The MRI system includes a magnet assembly that includes a gradient coil having a hollow conducting wire. The hollow conducting wire includes a body defining a passageway, and one or more conductors disposed within the body around the passageway.