MRI RF Antenna Galvanic-Inductive Coupling Noise Reduction
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Solution Overview
Problem
Conventional magnetic resonance imaging (MRI) systems require a separate transmit-receive box to manage the RF coil during transmit and receive phases, which can lead to signal path issues, noise contributions from cable currents, and ground loops, ultimately affecting image quality.
Innovation Solution
The proposed MRI system employs a radio-frequency (RF) antenna with an RF input terminal in galvanic connection and an RF output terminal in inductive coupling to the antenna, eliminating the need for a separate transmit-receive box. This configuration allows for independent optimization of the transmit and receive paths, reducing noise and improving image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate transmit-receive box is used to manage the RF coil during transmit and receive phases, then the RF coil can be properly managed during both phases, but signal path issues, noise contributions from cable currents, and ground loops occur, affecting image quality
Solution Approach 1:
The patent extracts the receive path from the traditional transmit-receive box architecture by providing a separate RF output terminal that is inductively coupled to the antenna. This separation removes the receive path from the galvanic connection issues present in conventional designs, eliminating noise contributions from cable currents and ground loops while maintaining proper RF coil management during both transmit and receive phases.
Solution Approach 2:
The patent introduces an inductive coupling as an intermediary mechanism between the RF output terminal and the antenna. This inductive coupling serves as a mediator that transfers signals without requiring galvanic connections, thereby avoiding the noise issues associated with cable currents and ground loops while still enabling effective signal reception.
2Power
If conventional birdcage resonators are directly fed at the coil ports using matching circuits, then power matching at the amplifier output is achieved, but the real part of the impedance changes significantly due to electric field losses, affecting resonance quality factor
Solution Approach 1:
The patent segments the RF input and RF output functions into separate terminals with different coupling methods. The RF input terminal uses galvanic connection for efficient power transfer during transmit, while the RF output terminal uses inductive coupling for noise-free signal reception during receive. This segmentation allows independent optimization of each function without compromising the other.
Solution Approach 2:
The patent applies different coupling qualities to different parts of the system: galvanic connection (high coupling strength) for the transmit path and inductive coupling (controlled coupling strength) for the receive path. This local differentiation of coupling quality allows optimal power transfer during transmit while maintaining stable impedance and high quality factor during receive.
3Adaptability or versatility
If a transmit-receive box is used to connect transmit and receive channels to the RF input ports of the body coil, then both channels can be connected at 3T, but the system architecture becomes more complex and requires additional components
Solution Approach 1:
The patent makes the antenna structure itself universal by integrating both transmit and receive capabilities directly into the antenna design. The RF input terminal handles transmit operations while the RF output terminal handles receive operations, eliminating the need for a separate transmit-receive box. This multi-functional integration simplifies the overall system architecture while maintaining adaptability for multi-channel connections.
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
By eliminating the need for a separate transmit-receive box and optimizing the RF paths, the system achieves improved signal-to-noise ratio, reduced noise contributions, and enhanced image quality, while also simplifying the system architecture and reducing costs.
Implementation Method 1
the RF input terminal is in galvanic connection to the antenna
Implementation Method 2
the antenna being adapted for picking up magnetic resonance signals
Implementation Method 3
the RF output terminal is inductively coupled to the antenna
Implementation Method 4
a main magnet for generating a main magnetic field within an imaging zone
Implementation Method 5
MRI is based on the principles of nuclear magnetic resonance
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The present disclosure relates to a magnetic resonance imaging system (100) comprising a main magnet (104) for generating a main magnetic field within an imaging zone (108); a radio frequency, RF, antenna (114), comprising an RF input terminal (300) and an RF output terminal (302); an RF system for supplying radio-frequency power to the RF input terminal (300) to energize the antenna (114), the antenna (114) being further adapted for 5 picking up magnetic resonance signals (144) from the imaging zone (108); a data acquisition system (126) for receiving the magnetic resonance signals (144) from the RF output terminal (302); wherein the RF input terminal (300) is in galvanic connection to the antenna (114) and the RF output terminal (302) is inductively coupled to the antenna (114)