Fictitious Field MRI Relaxation for Artifact-Free Imaging
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Solution Overview
Problem
Current magnetic resonance imaging (MRI) methods face limitations in observing fast decaying NMR signals, are susceptible to image artifacts from magnetic field inhomogeneity, and do not provide sufficient diagnostic and therapeutic image details, especially at high magnetic fields, which are costly and limited by specific absorption rates (SAR).
Innovation Solution
The use of frequency-swept pulses with sine and cosine amplitude and frequency modulations under non-adiabatic conditions generates fictitious magnetic fields, allowing for relaxation in rotating frames of rank n>2, reducing artifacts, and enabling the observation of very fast decaying signals by tuning the fictitious field amplitude and frequency to specific motional regimes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high magnetic fields are used for improved imaging, then image quality and diagnostic detail are improved, but specific absorption rate (SAR) increases and magnetic field inhomogeneity artifacts worsen
Solution Approach 1:
The patent transforms the imaging approach by changing from conventional high-field static imaging to low-field dynamic imaging with time-varying magnetic fields. This parameter transformation allows achieving high-resolution images at low static fields through motion encoding, thereby avoiding SAR limitations while maintaining diagnostic quality
Solution Approach 2:
The patent replaces the traditional mechanical/high-field magnetic resonance approach with a dynamic low-field approach using time-varying fields and motion encoding. This substitution fundamentally changes how magnetic resonance signals are generated and detected, eliminating SAR constraints inherent in high-field static systems
2Measurement precision
If high magnetic fields are used for improved imaging, then image quality is improved, but magnetic field inhomogeneity artifacts increase
Solution Approach 1:
The patent changes the operating parameters from high static field to low dynamic field with time-varying characteristics. This parameter transformation inherently reduces sensitivity to field inhomogeneity while maintaining imaging capability through motion-encoded signal generation
Solution Approach 2:
The patent introduces dynamic time-varying magnetic fields instead of static fields. The temporal variation of the magnetic field allows encoding of molecular motion information while being less susceptible to spatial inhomogeneities, thereby improving image reliability
3Measurement precision
If conventional MRI methods are used, then standard imaging is achieved, but fast decaying NMR signals cannot be observed
Solution Approach 1:
The patent applies preliminary motion encoding to magnetization before signal detection. By encoding molecular motion into the magnetic resonance signal in advance, the method preserves information from fast-decaying signals that would otherwise be lost in conventional imaging sequences
Solution Approach 2:
The patent replaces conventional signal detection methods with motion-encoded detection approaches. This substitution enables capturing fast-relaxing signal components by encoding their motion characteristics into observable signal variations rather than relying on signal amplitude alone
4Measurement precision
If traditional MRI contrast methods are used, then basic tissue contrast is achieved, but diagnostic and therapeutic image details are insufficient
Solution Approach 1:
The patent segments the magnetic resonance signal into multiple components based on different motion encoding frequencies. This segmentation allows separate observation of different molecular motion regimes, providing detailed diagnostic information about various tissue components and their dynamics
Solution Approach 2:
The patent uses dynamic motion encoding to capture different molecular motion characteristics. By varying the encoding parameters, the method extracts detailed information about molecular dynamics, providing enhanced diagnostic value beyond static tissue contrast
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 provides artifact-free rotary echoes, enhances the visibility of fast relaxing components, and allows for improved diagnostic imaging, including the investigation of diseases like Parkinson's and Alzheimer's, while reducing SAR and being less sensitive to magnetic field inhomogeneities.
Implementation Method 1
Magnetic resonance relaxation along a fictitious field
Implementation Method 2
frequency-swept (FS) pulses under non-adiabatic conditions and having sine and cosine amplitude and frequency modulations, respectively
Implementation Method 3
generates relaxation in the rotating frames of rank n>2 in the presence of time dependent fictitious fields
Implementation Method 4
producing relatively artifact-free rotary echoes in the rotating frames
Implementation Method 5
The resulting fictitious magnetic fields can be efficiently flipped, thus eliminating (or reducing) B0 and B1 artifacts
Implementation Method 6
allows for perfect refocusing of magnetization
Data Source
AI summary
A system includes a driving module, a processor, and a readout module. The driving module is configured to apply a perturbation to a sample. The processor is configured to define a plurality of different rotating frames relative to the perturbation, wherein each frame has a corresponding fictitious field. The readout module is coupled to the processor and is configured to generate an output based on relaxation of the sample as a function of the perturbation.