Adjustable MRI Coil with Proximity-Dependent Decoupling
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Solution Overview
Problem
Existing magnetic resonance imaging and spectroscopy technologies face limitations in achieving efficient radio frequency transmission and signal-to-noise ratio due to inadequate coil designs, particularly in high-field applications where sample-induced RF non-uniformities and varying specimen sizes complicate resonance element performance.
Innovation Solution
A geometrically adjustable multi-channel coil with decoupling capacitors that adjust capacitance based on proximity to adjacent elements, allowing for independent phase and amplitude control of resonant elements, and enabling flexible geometry configurations for improved RF shimming and parallel imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed geometry coil is used, then the coil structure is simple and easy to manufacture, but it cannot adapt to different specimen sizes and shapes, resulting in poor RF transmission efficiency and non-uniform signal reception
Solution Approach 1:
The patent implements a dynamically adjustable coil geometry system where resonant elements can be repositioned along radial and axial directions. The coil configuration changes from fixed to variable based on specimen requirements, allowing the same physical structure to adapt to different imaging needs without requiring multiple specialized coils.
Solution Approach 2:
The coil is divided into multiple independent resonant elements that can be individually positioned and controlled. Each resonant element can be adjusted independently in terms of position, phase, and amplitude, enabling flexible geometric configurations while maintaining manageable system complexity through modular design.
2Reliability
If resonant elements are positioned close together to improve filling factor, then signal-to-noise ratio improves, but mutual coupling between elements increases causing RF non-uniformities
Solution Approach 1:
The patent applies different decoupling strategies to different regions of the coil. Decoupling capacitors are selectively placed between adjacent resonant elements based on their specific coupling conditions. This localized approach allows strong coupling benefits in some regions while suppressing harmful mutual coupling in others, achieving non-uniform decoupling optimized for each position.
Solution Approach 2:
The system dynamically adjusts the coupling parameters between resonant elements by varying the positions of decoupling capacitors and adjusting the electrical characteristics of each element. This allows optimization of the coupling state based on the specific imaging application and specimen properties.
3Reliability
If decoupling capacitors are added between resonant elements to reduce mutual coupling, then RF non-uniformities are reduced, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The decoupling capacitors are integrated into the existing coil structure rather than being separate add-on components. The capacitors are positioned at specific locations between resonant elements and are designed to work as part of the overall coil assembly, simplifying manufacturing by combining multiple functions into a unified structure.
4Area of stationary object
If multiple resonant elements are used to improve coverage, then imaging performance improves, but phase variation and mismatch between elements increase
Solution Approach 1:
The system incorporates feedback mechanisms to monitor and adjust the phase and amplitude of each resonant element. By measuring the actual performance of each element and comparing it to the desired characteristics, the system can automatically tune and match the elements, reducing phase variation and improving overall coherence across the multi-element array.
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 solution enhances radio frequency transmit efficiency, signal-to-noise ratio, and imaging performance by allowing for adjustable coil geometry, equalized match capacitor values, and reduced phase variation, effectively mitigating sample-induced RF non-uniformities and improving coil performance across different subjects and specimen sizes.
Implementation Method 1
decoupling capacitors that adjust capacitance based on proximity to adjacent elements
Implementation Method 2
resonant elements, and enabling flexible geometry configurations for improved RF shimming and parallel imaging
Implementation Method 3
Magnetic resonance imaging and magnetic resonance spectroscopy involve providing an excitation signal to a specimen and detecting a response signal
Data Source
AI summary
This document discusses, among other things, a system and method for a coil having a plurality of resonant elements and an adjustable frame. A position of at least one resonant element can be adjusted relative to at least one other resonant element. A variable impedance is coupled to adjacent resonant elements and the impedance varies as a function of a separation distance. Cables are coupled to each resonant element and are gathered at a junction in a particular manner.