MRI Monomial RF Pulse Design for Broad Substance Suppression
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Solution Overview
Problem
Existing RF pulses in MRI scans struggle to effectively excite target substances while reliably suppressing other substances, particularly in high and ultra-high fields, due to limitations in frequency range suppression and sensitivity to B0 and B1 inhomogeneity, leading to reduced applicability and accuracy.
Innovation Solution
A monomial RF pulse with a trapezoidal waveform design, involving exponential transformation and filtering, is used to generate a waveform that excites target substances and suppresses others, with a semi-infinite stopband range for improved suppression and insensitivity to field inhomogeneity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional RF pulses are used to excite target substances, then the excitation of target substances can be achieved, but the suppression of other substances is insufficient and the frequency range of suppression is limited
Solution Approach 1:
The patent transforms the RF pulse waveform from conventional shapes (sinusoidal, rectangular) to a monomial waveform defined by y(t) = (t/T)^n where n is an odd integer. This parameter change in waveform shape creates a semi-infinite stopband that provides reliable suppression of unwanted substances across a broad frequency range, resolving the contradiction between suppression reliability and frequency range adaptability.
2Reliability
If conventional RF pulses are designed to suppress specific frequencies, then targeted suppression can be achieved, but the pulses become sensitive to B0 and B1 inhomogeneity reducing applicability
Solution Approach 1:
By changing the waveform parameter to a monomial shape with odd integer exponent n, the patent creates a frequency response with a semi-infinite stopband that is inherently robust against B0 and B1 inhomogeneity. This parameter transformation makes the suppression mechanism less sensitive to field variations, thereby improving applicability across high and ultra-high field strengths while maintaining reliable suppression.
3Ease of manufacture
If the RF pulse waveform is simplified for ease of generation, then device complexity is reduced, but the ability to selectively excite and suppress substances is compromised
Solution Approach 1:
The monomial waveform y(t) = (t/T)^n with odd integer n provides a mathematically simple yet physically powerful solution. The simplicity of the monomial function facilitates easy waveform generation, while the specific parameter choice (odd integer exponent) ensures the frequency response exhibits both the desired excitation passband and the suppressive stopband, thereby maintaining selective excitation and suppression accuracy without compromising generation simplicity.
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
The monomial RF pulse enhances MRI data accuracy by effectively exciting target substances and suppressing interference, improving signal-to-noise ratio and applicability across various field strengths, including high and ultra-high fields.
Implementation Method 1
Magnetic resonance (MR) technology has been widely used in various fields such as physics, chemistry, biology, and medicine
Data Source
AI summary
The present disclosure provides methods and systems for MRI. The method may include obtaining MRI data of a target subject. The MRI data may be collected by applying an MRI pulse sequence on the target subject. The MRI pulse sequence may include a monomial RF pulse for exciting first substance in the target subject and suppressing second substance in the target subject. The method may further include reconstructing a magnetic resonance (MR) image of the target subject based on the MRI data.