MRI RF Coil Constant Capacitance Coupling
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Solution Overview
Problem
Conventional MRI RF coils with off-coil circuitry via capacitive coupling experience varying capacitance issues, leading to sub-optimal tuning and performance due to the movement of coupling elements, which complicates signal transmission and reception during MRI procedures.
Innovation Solution
A system with a movable coil coupler and off-coil circuitry couplers arranged as capacitive plates, ensuring constant capacitance between the coil coupler and off-coil circuitry elements, maintaining the coil resonant frequency within a desired range by designing the coil and apparatus couplers to maintain consistent capacitance during movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If coil coupler elements are moved relative to apparatus coupler elements to facilitate patient movement, then ease of operation is improved, but capacitance varies leading to sub-optimal tuning
Solution Approach 1:
A capacitive coupling plate is introduced as an intermediary element between the coil coupler and apparatus coupler. This plate maintains a constant capacitance value (e.g., 50 pF) regardless of the relative positions of the coupler elements, thereby mediating the connection while preserving stable coil tuning during patient movement.
Solution Approach 2:
The invention changes the capacitance parameter from a variable value (dependent on coupler alignment) to a constant value (fixed at 50 pF). This is achieved by designing the capacitive coupling plate with specific geometric parameters (area, spacing) that ensure constant capacitance across the range of motion, allowing the coil to remain tuned to the Larmor frequency throughout the procedure.
2Adaptability or versatility
If manual plugging and unplugging of coil connectors is performed, then adaptability is improved, but device complexity and wear increase
Solution Approach 1:
The system automatically maintains electrical connection between the coil and apparatus through the capacitive coupling plate during patient movement. The coil coupler and apparatus coupler remain in continuous contact (or near-contact) without requiring manual intervention, allowing the system to serve itself by maintaining connectivity while accommodating position changes.
Solution Approach 2:
The traditional mechanical connector is extracted and replaced with a capacitive coupling mechanism. This eliminates the need for plugging and unplugging physical connectors, reducing mechanical wear while maintaining the ability to selectively use different coils during the MRI procedure.
3Ease of operation
If capacitance is allowed to vary with coupler movement, then ease of operation is improved, but signal transmission quality deteriorates
Solution Approach 1:
The capacitive coupling plate serves as a mediator that decouples the signal transmission quality from the mechanical position of the couplers. By providing a fixed capacitance value independent of position, it ensures consistent signal transmission quality while allowing continuous patient movement during the MRI procedure.
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 design maintains consistent capacitance, ensuring the MRI RF coil remains tuned to the desired frequency, improving signal transmission and reception quality and reducing the need for manual coil connections, thus minimizing operator time and equipment wear.
Implementation Method 1
Magnetic resonance imaging (MRI) coil with constant capacitance coupling... connected to off coil circuitry by capacitive coupling plates... ensuring constant capacitance between the coil coupler and off-coil circuitry elements
Implementation Method 2
Magnetic resonance imaging (MRI) involves the transmission and receipt of radio frequency (RF) energy... resulting magnetic resonance (MR) signals may also be received by a coil... maintaining the coil resonant frequency within a desired range
Data Source
AI summary
Example minimalist magnetic resonance imaging (MRI) radio frequency (RF) coils that are connected to off coil circuitry by capacitive coupling plates are described. A minimalist MRI RF coil may have some elements that form a traditional coil located off the coil in off coil circuitry. An MR procedure may involve a number of minimalist MRI RF coils that are moved through an excitation zone as a patient is moved through the excitation zone. Example minimalist MRI RF coils may be selectively connected to off coil circuitry while the coils are in the excitation zone. The coupling may be made by capacitive coupling plates. Unlike conventional systems, example systems have capacitive coupling plates with properties that facilitate maintaining a constant capacitance between a coupling plate associated with the coil and coupling plates associated with the off coil circuitry as the coupling plates move relative to each other.