MRI RF Pulse Frequency Shifting for Slice Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Magnetic resonance imaging (MRI) techniques face challenges in obtaining clear images across multiple slices due to overlap caused by off-resonance components, requiring multiple scanning operations.
Innovation Solution
A magnetic resonance imaging apparatus and method that corrects errors due to off-resonance components by shifting the center frequency of RF pulses applied to different slices, ensuring the same bandwidth and adjusting the slice gap to prevent overlap, using a controller to manage RF coil assemblies and gradient coils to form appropriate magnetic field gradients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple scanning operations are performed to obtain magnetic resonance images of multiple slices, then the diagnostic information can be acquired, but overlap between the respective magnetic resonance images occurs due to off-resonance components
Solution Approach 1:
The patent applies parameter changes by shifting the center frequency of RF pulses for different slices. Specifically, the first RF pulse has a center frequency of f0, while the second RF pulse has a center frequency of f0-Δf. This frequency parameter change compensates for off-resonance effects and prevents image overlap, allowing multiple slices to be imaged without interference.
2Reliability
If the center frequency of RF pulses is shifted for different slices, then off-resonance errors are corrected, but the device complexity increases due to frequency management requirements
Solution Approach 1:
The controller changes the center frequency parameter of RF pulses based on the slice being imaged. The first RF pulse uses center frequency f0 and the second RF pulse uses center frequency f0-Δf. This systematic parameter change approach provides reliable error correction while maintaining manageable device complexity through algorithmic frequency management.
3Productivity
If a single scanning operation is used to acquire multiple slices, then productivity is improved, but overlap between slices occurs due to off-resonance components
Solution Approach 1:
The patent enables single-scanning multi-slice imaging by changing the center frequency parameter of RF pulses for different slices. The first slice is imaged with RF pulse center frequency f0, while the second slice uses center frequency f0-Δf. This parameter differentiation allows simultaneous acquisition of multiple slices without overlap, significantly improving productivity while preventing harmful 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
Enables the acquisition of magnetic resonance images with reduced overlap between slices through single scanning, improving diagnostic accuracy by isolating on-resonance components and eliminating interference from off-resonance components.
Implementation Method 1
a main magnet which generates a static magnetic field in an imaging region
Implementation Method 2
gradient coils which form magnetic field gradients in the static magnetic field
Implementation Method 3
Magnetic resonance imaging (MRI) enables a nuclear magnetic resonance phenomenon to occur in hydrogen atomic nuclei in the human body by using a magnetic field harmless to the human body and a radio wave
Implementation Method 4
a radio frequency (RF) coil assembly which applies a first RF pulse and a second RF pulse to n (n≧2) slice regions located at different positions in the imaging region to excite atomic nuclei of the slice regions
Data Source
AI summary
The magnetic resonance imaging apparatus includes a main magnet to generate a static magnetic field in an imaging region, a gradient coil assembly to form a gradient in the static magnetic field, a radio frequency (RF) coil assembly to apply a first RF pulse and second RF pulse with respect to n (n≧2) slice regions located at different positions in the imaging region, to excite atomic nuclei of the slice regions, and a controller to control the RF coil assembly to apply a first RF pulse and second RF pulse having a first center frequency f0 to a first slice and to apply a first RF pulse having a second center frequency f0+fs1 and a second RF pulse having a third center frequency f0−fs1 to a second slice.