Multi-port RF Volume Resonator for MRI Homogeneity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing RF volume resonator systems face challenges in maintaining homogeneity of the RF field and specific absorption rate (SAR) due to variations in patient physical properties such as weight, fat, and water content, which complicates tuning and affects image quality in MRI systems.
Innovation Solution
A multi-port RF volume resonator system with independently controllable ports and channels, where each port is connected to a matching network and an ON/OFF switch, allowing for selective activation and deactivation of ports to optimize RF field homogeneity and SAR, using a control unit to adjust parameters based on patient properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a multi-port RF volume resonator is used to improve RF field homogeneity and SAR management, then the homogeneity and SAR control are improved, but the device complexity increases due to multiple ports and channels
Solution Approach 1:
The RF volume resonator is divided into multiple independent ports, each capable of being selectively activated or deactivated. This segmentation allows independent control of RF field excitation from different ports, enabling optimization of field homogeneity and SAR management by activating only the necessary ports for each imaging scenario.
Solution Approach 2:
The system implements dynamic control of port activation through ON/OFF switches and matching networks that can be adjusted based on patient properties and imaging requirements. This dynamic adaptability allows the system to optimize performance by changing which ports are active, rather than using a fixed configuration.
2Manufacturing precision
If ports are selectively activated based on patient properties to improve imaging performance, then image quality is improved, but the control system complexity increases
Solution Approach 1:
The control unit receives information about patient properties and uses this feedback to determine which ports should be activated. This feedback mechanism allows the system to adapt its configuration based on actual patient characteristics, optimizing image quality while managing control complexity through intelligent decision-making algorithms.
Solution Approach 2:
The system changes operational parameters (which ports are active) based on patient properties such as weight, fat content, and water content. By adjusting the configuration of active ports according to these parameters, the system optimizes RF field distribution and image quality for different patient types without requiring a completely different system design.
3Manufacturing precision
If multiple transmit channels are used to improve RF field distribution, then the RF field homogeneity is improved, but the power requirements and energy consumption increase
Solution Approach 1:
Instead of activating all available transmit channels simultaneously, the system uses only the necessary number of ports required to achieve the desired RF field homogeneity. This partial action approach reduces power consumption while maintaining adequate field distribution by selecting a subset of ports that provides sufficient performance.
Solution Approach 2:
The system applies different excitation strategies to different regions of the resonator by selectively activating specific ports. Each port contributes to the RF field in its local region, and by choosing which ports to activate, the system optimizes local field quality without requiring all ports to be active, thereby reducing overall power consumption.
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 ensures a more homogeneous RF field distribution and improved SAR management, reducing the impact of patient-specific variations on image quality and power distribution, enabling better MRI performance across different patient types.
Implementation Method 1
by driving the RF resonator at one or two ports by an RF current source, a number of linearly independent resonant current distributions ('resonant modes') can be excited in the RF resonator for generating magnetic fields at certain resonance frequencies
Implementation Method 2
Each port is connected with a matching network, which is provided for matching the port to the connected transmit or receive channel
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
An RF volume resonator systemis disclosed comprising a multi-port RF volume resonator (40, 50; 60), like e.g. a TEM volume coil or TEM resonator, or a birdcage coil, all of those especially in the form of a local coil like a head coil, or a whole body coil, and a plurality of transmit and/or receive channels (T/RCh1,...T/RCh8) for operating the multi-port RF volume resonator for transmitting RF excitation signals and/or for receiving MR relaxation signals into/from an examination object or a part thereof. By the individual selection of each port (P1,..P8) andthe appropriate amplitude and/or frequency and/or phase and/or pulse shapes of the RF transmit signals according to the physical properties of an examination object, a resonant RF mode within the examination object with an improved homogeneitycan beexcited bythe RF resonator.