MRI RF Coil Current Control via λ/4 Coaxial Lines
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Solution Overview
Problem
Conventional MRI systems face challenges in achieving homogeneous B1 fields due to interactions between the B1 field and tissue at higher B0 fields, leading to image quality issues, and existing solutions like multiple RF transmission coils are costly, complex, and difficult to control, especially at high frequencies.
Innovation Solution
The use of MRI RF coils configured with λ/4 or λ/2 coaxial transmission lines to connect loop coils in series or parallel, allowing for easier tuning and control of current magnitudes across coils, thereby achieving uniform B1 fields without the need for multiple isolation power amplifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple RF transmission coils are used to produce homogeneous B1 fields, then B1 field homogeneity is improved, but device complexity and cost increase
Solution Approach 1:
The patent divides a single RF coil into multiple sections along its length, with each section independently controllable through separate current magnitude control. This segmentation allows different sections to be tuned to compensate for B1 non-uniformity without requiring multiple separate coils, thus achieving homogeneous B1 fields while reducing system complexity
Solution Approach 2:
The patent implements local quality control by enabling independent current magnitude adjustment for different sections of the coil. This allows each section to be optimized for its specific spatial region, creating locally adapted B1 field characteristics that collectively produce overall field homogeneity
2Manufacturing precision
If multiple RF transmission coils are used to produce homogeneous B1 fields, then B1 field homogeneity is improved, but system cost increases
Solution Approach 1:
The patent merges multiple coil sections into a single integrated RF coil structure that shares common support infrastructure, tuning mechanisms, and control systems. This consolidation achieves the B1 homogeneity benefits of multiple coils while reducing overall system cost by eliminating redundant components
3Manufacturing precision
If current magnitude is controlled at different coil sections, then B1 field homogeneity is improved, but control difficulty increases
Solution Approach 1:
The patent introduces an intermediary control system that manages current distribution across coil sections. This intermediary layer simplifies operator interaction by providing unified control interfaces and automated tuning algorithms, making multi-section current control as easy as conventional single-coil operation
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 the tuning process, reduces costs, and enhances the homogeneity of B1 fields, improving the quality of MRI images by allowing for customizable B1 fields across different points in the imaging area.
Implementation Method 1
RF coils create the B1 field that rotates the net magnetization in a pulse sequence
Implementation Method 2
configured with λ/4 or λ/2 coaxial transmission lines to connect loop coils
Data Source
AI summary
Example apparatus and magnetic resonance imaging (MRI) radio frequency (RF) coils concern controlling current magnitude at different sections in one MRI RF coil. In one embodiment, an MRI RF coil comprises a plurality of loop coils configured to transmit or receive an RF signal. A member of the plurality of loop coils comprises an inductor and at least one capacitor. The MRI RF coil further comprises at least one coaxial transmission line that electrically couple in series a first member of the plurality of loop coils with a second, different member of the plurality of loop coils. The at least one coaxial transmission line has a length that is one-quarter wavelength (λ/4) of the RF signal, or an odd integer multiple of λ/4 of the RF signal.