Moving RF Coil for MRI Scan Time Reduction
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Solution Overview
Problem
Current MRI systems face limitations in reducing scan time and minimizing deleterious effects from gradient coil switching, while also struggling with signal-to-noise ratio and RF field homogeneity issues, particularly at high magnetic field strengths.
Innovation Solution
The implementation of a moving coil or shield system within the MRI apparatus, which rotates or moves relative to the imaging region to modify the electromagnetic field and sensitivity distribution, allowing for improved image quality and reduced scan time without the need for extensive hardware or complex coil arrays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gradient coils are switched rapidly to reduce scan time, then productivity is improved, but harmful factors increase due to peripheral nerve stimulation and acoustic noise
Solution Approach 1:
The patent applies the dynamics principle by making the RF coil movable rather than stationary. The coil is moved along the z-axis during the imaging process, which allows the system to acquire signal information from multiple locations sequentially. This dynamic movement enables reduced gradient switching requirements while maintaining imaging quality, thereby reducing peripheral nerve stimulation and acoustic noise while preserving scan efficiency
Solution Approach 2:
The patent introduces movement along the z-axis dimension, adding a spatial dimension to the traditional stationary coil imaging approach. By moving the coil along the longitudinal axis, the system can acquire data from different positions without requiring rapid gradient switching in the transverse plane, thus reducing harmful effects while maintaining productivity
2Measurement precision
If multiple coils are used to improve signal-to-noise ratio, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent uses a single movable coil instead of multiple stationary coils. By moving the single coil to different positions along the z-axis and acquiring signals sequentially, the system achieves comparable signal-to-noise ratio performance without the complexity of multiple coils and their associated electronics, cable connections, and synchronization requirements
Solution Approach 2:
The patent creates multiple virtual coil positions by physically moving a single coil through different locations. This copying approach allows the system to obtain signal information from multiple effective positions without requiring multiple physical coils, thereby maintaining measurement precision while reducing device complexity
3Measurement precision
If RF power is increased to improve signal quality, then measurement precision is improved, but harmful factors increase due to SAR
Solution Approach 1:
The patent employs dynamic coil movement to improve signal quality without increasing RF power. By moving the coil to positions with better signal characteristics and acquiring data sequentially, the system maintains high measurement precision while using lower RF power levels, thereby reducing SAR and associated harmful effects
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 enables efficient image acquisition with reduced peripheral nerve stimulation, acoustic noise, and image artifacts, while maintaining or improving signal quality and reducing the Specific Absorption Rate (SAR), thus enhancing the overall MRI process.
Implementation Method 1
at least one coil for at least one of transmitting, receiving or transceiving an electromagnetic field
Implementation Method 2
moving the field component relative to the imaging region to thereby modify the electromagnetic field
Data Source
AI summary
Apparatus for use in a magnetic resonance imaging system, the imaging system generating a magnetic imaging field in an imaging region (5), the apparatus including at least one coil for at least one of transmitting, receiving or transceiving an electromagnetic field, a field component (4) (such as a coil or a shield) and a drive (6) coupled to the field component for moving the field component (4) relative to the imaging region (5) to thereby modify the electromagnetic field during imaging process. The same concept can also be applied to nuclear imaging or nuclear spectroscopy apparatus.