Nested Multiturn RF Coil Assemblies for MRI Signal-to-Noise Ratio
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Solution Overview
Problem
Conventional MRI systems face challenges in achieving high signal-to-noise ratio (SNR) at lower magnetic field strengths, which limits their imaging capabilities and efficiency.
Innovation Solution
The RF coil assembly incorporates multiturn loops with an inner and outer loop configuration, where the inner loop is at least partially nested within the outer loop, and includes passive isolation circuits or inductor pairs to electromagnetically isolate loops, enhancing signal collection while managing coil losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional single-turn loops are used in RF coil assemblies, then the device complexity is low, but the signal-to-noise ratio is insufficient at lower magnetic field strengths
Solution Approach 1:
The patent implements multiturn loops where inner loops are nested within outer loops, with each subsequent loop having a smaller area than the previous one. This nesting configuration increases the signal-to-noise ratio by collecting more RF signals while maintaining a compact structure that fits within the MRI bore.
Solution Approach 2:
The patent transitions from single-turn to multiturn loops, adding the dimension of multiple turns within the same physical footprint. This dimensional change increases the effective area for signal collection without proportionally increasing the coil's external dimensions, thereby improving SNR.
2Area of stationary object
If multiple RF coil assemblies are used to improve imaging coverage, then the imaging coverage is increased, but electromagnetic interference between adjacent coils increases
Solution Approach 1:
The patent introduces passive isolation circuits as intermediary elements between adjacent multiturn loops. These isolation circuits act as mediators that block electromagnetic interference between coils while allowing each coil to function independently, enabling closer placement of multiple coils to expand imaging coverage.
Solution Approach 2:
The patent divides the RF coil system into multiple independent multiturn loop assemblies, each capable of functioning separately. The segmentation is enhanced by placing isolation circuits between adjacent loops, allowing the system to achieve broader coverage through multiple coils without suffering from mutual interference.
3Measurement precision
If multiturn loops with nested configuration are used, then the collected RF signal is significantly increased, but coil losses increase
Solution Approach 1:
Passive isolation circuits are placed between adjacent multiturn loops to prevent electromagnetic coupling and energy loss between neighboring coils. These isolation circuits act as intermediaries that maintain the high signal collection capability of multiturn loops while preventing energy dissipation through inter-coil interference.
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 configuration significantly increases the collected RF signal, achieving a 35% higher signal-to-noise ratio compared to single-turn loop assemblies, while maintaining manageable coil losses, thus improving MRI imaging quality at various magnetic field strengths.
Implementation Method 1
A passive isolation circuit can be disposed in the common conductor to electromagnetically isolate the first multiturn loop and the second multiturn loop
Implementation Method 2
An inductor pair can be connected between the first multiturn loop and the third multiturn loop to electromagnetically isolate the first multiturn loop and the third multiturn loop
Implementation Method 3
RF coils may be used to excite atoms in patient tissues to emit RF radiation that may then be detected by RF coils (in the form of varying magnetic flux through the RF coil)
Data Source
AI summary
RF coil assemblies are disclosed that include multiturn loops formed of conductors configured to receive RF signals from a patient during MRI. The multiturn loops include an inner loop and an outer loop that both lie substantially in a plane of the RF coil assembly. The inner loop is at least partially nested within the outer loop.