Segmented RF Coil Rungs for MRI Eddy Current Suppression
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Solution Overview
Problem
Magnetic Resonance Imaging (MRI) systems face issues with acoustic noise and vibration caused by eddy currents in Radio Frequency (RF) coils, leading to patient discomfort and reduced system efficiency due to heat generation.
Innovation Solution
The RF coil design includes a configuration with a first and second end ring and a plurality of rungs, where each rung has a portion formed from multiple conductors and another portion formed from a single solid conductor, which helps in reducing eddy currents and providing a more uniform magnetic field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional RF coil conductors are used, then RF signal transmission is achieved, but eddy currents are induced causing acoustic noise and vibration
Solution Approach 1:
The RF coil conductors are segmented into multiple separate conductors instead of using a single solid conductor. This segmentation disrupts the continuous path for eddy currents, reducing their magnitude and thereby decreasing acoustic noise and vibration while maintaining RF signal transmission capability
Solution Approach 2:
Different portions of the RF coil structure have different conductor configurations optimized for their specific functions. The end rings use solid conductors for efficient RF signal transmission, while the rungs use multiple conductors to minimize eddy currents, creating local quality variations that resolve the contradiction between noise reduction and performance maintenance
2Measurement precision
If gradient coils operate to generate time-varying magnetic fields, then spatial encoding is achieved, but eddy currents are induced in RF coils causing heat generation
Solution Approach 1:
The RF coil rungs are divided into multiple conductors that are electrically connected in parallel. This segmentation increases the overall resistance to eddy current flow while maintaining RF signal characteristics, thereby reducing heat generation from eddy currents during gradient coil operation while preserving spatial encoding capability
Solution Approach 2:
The RF coil employs a composite conductor structure combining multiple conductive materials or configurations (solid end rings with multi-conductor rungs) that exhibit different electrical properties. This composite structure optimizes both RF signal transmission and eddy current suppression, reducing heat generation while maintaining imaging precision
3Power
If RF coil conductors are configured for optimal RF performance, then signal transmission is enhanced, but acoustic noise and vibration increase
Solution Approach 1:
The RF coil implements local quality differentiation where end rings use solid conductors for optimal RF signal transmission and power handling, while the rungs connecting them use multiple conductors to minimize eddy currents and reduce vibration. This localized optimization resolves the contradiction between RF power performance and vibration reduction
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 minimizes acoustic noise and vibration, enhances RF performance, and maintains patient comfort by reducing heat generation, thereby improving the overall efficiency of the MRI system.
Implementation Method 1
Radio frequency (RF) coils are used to create pulses of RF energy at or near the resonance frequency of the hydrogen nuclei
Implementation Method 2
The acoustic noise generated by the RF coil is typically caused by eddy currents induced in the RF coil conductors by operation of the gradient coils
Implementation Method 3
These time-varying magnetic fields can induce eddy currents in an RF coil that cause motion or vibration of the RF coil and result in acoustic noise
Implementation Method 4
In addition, the eddy currents induced in the RF coils can produce heat. The heat produced by the RF coils may cause an increase in the temperature of the patient bore
Data Source
AI summary
A radio frequency (RF) coil for a magnetic resonance imaging (MRI) system includes a first end ring, a second end ring, and a plurality of rungs electrically coupled between the first and second end rings, each rung including a first rung portion formed from a plurality of conductors and a second rung portion formed from a single solid conductor. A resonance assembly for a magnetic resonance imaging (MRI) system and an MRI imaging system are also described herein.