RF Spoiling for Rapid Spatial Saturation in MRI
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Solution Overview
Problem
Current RF spoiling methods are inadequate for rapid spatial saturation modes in magnetic resonance imaging, leading to residual signal coherence and artefacts in images.
Innovation Solution
An RF spoiling method that applies multiple RF pulses of a spatial saturation module with phases that are not coherent with those of the imaging sequence, ensuring independent phase cycles to effectively destroy residual signal coherence and reduce artefacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a standard RF spoiling method with linearly increasing phase increments is applied to a spatial saturation module, then the phase coherence between adjacent RF pulses is maintained, but residual spin coherence remains in the transverse plane and artefacts appear in the image when using rapid spatial saturation mode
Solution Approach 1:
The patent changes the phase increment parameter from a fixed linear increment to a variable increment that depends on the number of echoes in the echo train. Specifically, the phase increment is set to 360°/N where N is the number of echoes, ensuring that the total phase change over the echo train is a multiple of 360°, thereby eliminating residual coherence and preventing artefacts
Solution Approach 2:
The patent makes the RF spoiling strategy dynamic by adapting the phase increment to the specific imaging sequence parameters (number of echoes). This dynamic adjustment ensures optimal spoiling performance for different rapid gradient echo sequences while maintaining compatibility with the imaging protocol
2Productivity
If one spatial saturation module is applied for multiple echoes or echo trains to reduce acquisition time, then productivity is improved, but the existing RF spoiling method becomes inadequate and fails to eliminate residual coherence
Solution Approach 1:
The patent modifies the phase increment parameter to account for multiple echoes within a single spatial saturation module. By setting the phase increment to 360°/N where N is the number of echoes, the method ensures effective spoiling even when one saturation module serves multiple echoes, thus maintaining reliability while preserving the productivity gains of rapid spatial saturation mode
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 improves imaging quality by eliminating artefacts and ensuring uniform dispersion of residual signals, without requiring hardware changes, thus enhancing the effectiveness of rapid spatial saturation techniques.
Implementation Method 1
RF spoiling rotates the phase of an RF pulse in a predetermined manner, and is an effective technique for eliminating residual spin coherence in the transverse plane
Implementation Method 2
induce oscillation of precessing hydrogen nuclei (i.e. H+) in human tissue, and thereby generate RF signals
Implementation Method 3
electromagnetic waves that are thereby emitted are spatially encoded by activating gradient fields and are then evaluated to identify the positions and types of the atomic nuclei
Data Source
AI summary
In an RF spoiling method and apparatus for rapid spatial saturation in magnetic resonance imaging, a first RF pulse of a spatial saturation module is applied, and a first set of RF pulses of an imaging sequence is applied after the first RF pulse. A phase of an RF pulse, closest to the first RF pulse in the time dimension, in the first set of RF pulses is not coherent with a phase of the first RF pulse. This makes a phase cycle of the spatial saturation module and a phase cycle of the imaging sequence independent of each other, so the coherence of residual signals in the transverse plane can be destroyed more effectively, thereby reducing artefacts, and improving imaging quality.