NMR Fingerprinting for Simultaneous Relaxation Parameter Acquisition
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Solution Overview
Problem
Conventional magnetic resonance (MR) pulse sequences are time-consuming and limited in their ability to acquire precise quantitative data, particularly for multiple relaxation parameters simultaneously, which hampers three-dimensional imaging and imaging of moving targets, and relies on subjective interpretations due to qualitative image analysis.
Innovation Solution
The implementation of NMR fingerprinting, which involves applying a series of varied sequence blocks to generate unique signal evolutions for different resonant species, allowing for pattern recognition and characterization of tissues based on signal evolutions compared to known or simulated patterns, enabling simultaneous acquisition and identification of multiple relaxation parameters without the need for conventional reconstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional MR pulse sequences are used to acquire multiple relaxation parameters, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The patent combines multiple pulse sequences with different weightings (T1-weighted, T2-weighted, PD-weighted) into a single integrated acquisition. Instead of sequentially acquiring each parameter separately, the system simultaneously captures signal evolutions for multiple relaxation parameters through a unified pulse sequence design, thereby reducing total acquisition time while maintaining quantitative measurement precision.
Solution Approach 2:
The patent employs dynamic pulse sequences where parameters such as flip angle and echo time are varied across multiple repetitions rather than held constant. This dynamic approach allows the system to encode multiple relaxation parameters within a single time-efficient acquisition window, resolving the contradiction between comprehensive measurement and time consumption.
2Measurement precision
If multiple pulse sequences are applied to acquire different weighted signals, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent designs a universal pulse sequence framework that can simultaneously acquire multiple relaxation parameters (T1, T2, PD) and generate multiple types of weighted signals within a single acquisition protocol. This multi-functional sequence reduces the need for multiple separate pulse sequences and their associated complex registration procedures, thereby simplifying the overall system while maintaining high measurement precision.
3Manufacturing precision
If conventional MR acquisition is used to acquire signals from precise locations at precise points in time, then manufacturing precision is improved, but loss of information increases
Solution Approach 1:
The patent implements continuous signal acquisition through repeated pulse sequence applications, capturing signal evolutions over extended time periods. This continuous sampling approach ensures that no valuable information is lost while maintaining precise spatial and temporal localization of signals from different tissue types and relaxation parameters.
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 significantly reduces acquisition time, enhances the ability to image moving targets, and provides more objective and quantitative tissue characterization by generating unique signal evolutions for each combination of resonant species, overcoming the limitations of conventional MR techniques.
Implementation Method 1
Nuclear magnetic resonance (NMR) fingerprinting
Data Source
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AI summary
Apparatus, methods, and other embodiments associated with NMR fingerprinting are described. One example NMR apparatus includes an NMR logic configured to repetitively and variably sample a (k, t, E) space associated with an object to acquire a set of NMR signals. Members of the set of NMR signals are associated with different points in the (k, t, E) space. Sampling is performed with t and/or E varying in a non-constant way. The varying parameters may include flip angle, echo time, RF amplitude, and other parameters. The NMR apparatus may also include a signal logic configured to produce an NMR signal evolution from the NMR signals, and a characterization logic configured to characterize a resonant species in the object as a result of comparing acquired signals to reference signals.