RF Pulse Waveform Determination via Reciprocity in MRI
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Solution Overview
Problem
Magnetic resonance methods require significant time and computing effort, and are sensitive to external interference such as field inhomogeneities, which can lead to inaccurate selective excitations.
Innovation Solution
A method using the principles of reciprocity and time invariance to convert the inversion problem into a simpler form, allowing for the direct determination of high-frequency pulses that are insensitive to interference and can be computed efficiently, even with multiple excitation channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional magnetic resonance methods are used for selective excitation, then spatial selectivity can be achieved, but significant time and computational resources are required
Solution Approach 1:
The patent inverts the conventional approach by formulating the selective excitation problem as an inverse problem. Instead of directly calculating the RF pulse waveform to achieve desired spatial selectivity, the method uses the reciprocity principle to relate the excitation problem to a signal acquisition problem. This inversion transforms a computationally intensive forward problem into a more efficiently solvable inverse problem, reducing computation time while maintaining excitation accuracy.
Solution Approach 2:
The patent employs the reciprocity principle to create a mathematical copy of the excitation problem in the form of an equivalent signal acquisition problem. By solving this copied inverse problem, the desired RF pulse waveforms are obtained without directly solving the original complex forward excitation equations, thereby reducing computational resources and time requirements.
2Measurement precision
If conventional magnetic resonance methods are used for selective excitation, then spatial selectivity can be achieved, but the methods require significant computational effort
Solution Approach 1:
The patent inverts the conventional approach by formulating the selective excitation problem as an inverse problem. Instead of directly calculating the RF pulse waveform to achieve desired spatial selectivity, the method uses the reciprocity principle to relate the excitation problem to a signal acquisition problem. This inversion transforms a computationally intensive forward problem into a more efficiently solvable inverse problem, reducing computational resources and time requirements.
Solution Approach 2:
The patent employs the reciprocity principle to create a mathematical copy of the excitation problem in the form of an equivalent signal acquisition problem. By solving this copied inverse problem, the desired RF pulse waveforms are obtained without directly solving the original complex forward excitation equations, thereby reducing computational resources and time requirements.
3Measurement precision
If conventional magnetic resonance methods are used for selective excitation, then excitation patterns can be generated, but the methods are sensitive to external interference such as field inhomogeneities
Solution Approach 1:
The patent inverts the conventional approach by formulating the selective excitation problem as an inverse problem. Instead of directly calculating the RF pulse waveform to achieve desired spatial selectivity, the method uses the reciprocity principle to relate the excitation problem to a signal acquisition problem. This inversion transforms a computationally intensive forward problem into a more efficiently solvable inverse problem, reducing computation time while maintaining excitation accuracy.
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 results in robust, quick, and accurate selective excitations that are insensitive to field inhomogeneities and relaxation, enabling efficient magnetic resonance imaging with reduced computational effort.
Implementation Method 1
A method using the principles of reciprocity and time invariance to convert the inversion problem into a simpler form
Implementation Method 2
A method using the principles of reciprocity and time invariance to convert the inversion problem into a simpler form
Implementation Method 3
magnetic resonance methods require significant time and computing effort
Implementation Method 4
The fundamental principles of spatially resolved nuclear magnetic resonance
Data Source
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AI summary
The invention relates to a magnetic resonance method, wherein high-frequency pulses and magnetic gradients (gx, gy, gz) are produced in order to selectively excite an object to be examined. According to the invention, the magnetic resonance method is characterized in that a magnetic resonance signal s(t) is produced according to the following signal equation: (I), wherein (II) denotes a desired transverse magnetization after the selective excitation, t denotes a time, (III) denotes a position vector, and T denotes a duration of a pulse, wherein s(t) denotes a magnetic resonance signal, V denotes an examination volume, T 2 denotes a transverse relaxation time, and ? s denotes a shift of the resonance frequency. The invention further relates to a magnetic resonance tomograph for carrying out the magnetic resonance method.