Single Coaxial MR Coil Interface for Crosstalk Reduction
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Solution Overview
Problem
State-of-the-art MR coil arrays face challenges with high cost, complexity, and image quality issues due to the need for separate transmission lines for power, RF signals, and tune/detune control signals, which lead to crosstalk and transmission line modes that affect system stability.
Innovation Solution
Combining power, RF signal output, and tune/detune control signals onto a single coaxial transmission line, using varying DC voltages to power active components and control coil elements, reducing the number of internal cables and connectors, and employing a tune/detune circuit connected to the coaxial line to manage coil tuning and detuning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate transmission lines are used for power, RF signals, and tune/detune control signals, then each signal can be transmitted independently, but the device complexity and cost increase due to multiple cables and connectors
Solution Approach 1:
The patent combines power, RF signal, and tune/detune control signals onto a single coaxial transmission line. The power signal is transmitted on the outer conductor, RF signals on the inner conductor, and tune/detune control signals are superimposed on the power signal using capacitive coupling, eliminating the need for separate transmission lines for each signal type.
Solution Approach 2:
The single coaxial transmission line serves multiple functions simultaneously: it provides power delivery, RF signal transmission, and tune/detune control. This multi-functional approach replaces what would traditionally require three separate transmission lines, reducing complexity while maintaining signal independence through frequency and impedance differentiation.
2Reliability
If separate transmission lines are used for power, RF signals, and tune/detune control signals, then each signal has dedicated path, but cost increases due to additional Baluns, RF traps, and connectors
Solution Approach 1:
The patent eliminates the need for separate Baluns and RF traps by combining all signals on a single coaxial line. The impedance matching and signal isolation are achieved through circuit design at the coil element board level rather than requiring additional components on the transmission line.
Solution Approach 2:
The patent extracts the tune/detune control signal from a separate transmission line and superimposes it on the existing power signal using capacitive coupling. This eliminates the need for a dedicated tune/detune transmission line while maintaining proper signal isolation through frequency differentiation.
3Reliability
If multiple separate transmission lines are used, then each signal can be transmitted independently, but crosstalk and transmission line modes occur affecting image quality
Solution Approach 1:
The patent merges all signals onto a single transmission line to eliminate coupling between adjacent transmission lines, which is the source of crosstalk and unwanted transmission line modes. Signal independence is maintained through frequency and impedance differentiation rather than physical separation.
4Reliability
If Baluns and RF traps are added to reduce RF currents on cables during TX phase, then safety is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the tune/detune control function from a separate transmission line and implements it through capacitive coupling on the power line, eliminating the need for separate Balun and RF trap circuits while maintaining RF current suppression during transmit phase.
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 simplifies cabling, reduces crosstalk and transmission line modes, enhances system stability, and improves image quality while lowering costs and complexity.
Implementation Method 1
The coil element circuit includes a tune/detune circuit connected to the coaxial transmission line. The tune/detune circuit tunes or detunes the coil element based on the first and second DC voltages of the power signal.
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A magnetic resonance (MR) coil array (26, 28) connected by way of a single transmission line (46, 48) is provided. The MR coil array (26, 28) includes a coil element (34) and a corresponding coil element circuit (32). The coil element circuit (32) includes at least one active component (40) powered by a power signal carried on the coaxial transmission line (46, 48). The voltage of the power signal varies between first and second direct current (DC) voltages of the same polarity. The coil element circuit (32) further includes a tune/detune circuit (42) connected to the coaxial transmission line (46, 48). The tune/detune circuit (42) tunes or detunes the coil element (34) based on the first and second DC voltages. An MR system (10) using the MR coil array (26, 28) and a method (10) for tuning or detuning the MR coil (26, 28) are also provided. Accordingly, a single coaxial cable between the MR system and the coil element is sufficient for conveying MR data, a power signal for the preamplifier and a detuning signal. Moreover, the preamplifier can be powered irrespective of the coil element being in the tuned or in the detuned state.