NMR Parameter Reconstruction Using k-Space Gradients
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Solution Overview
Problem
Conventional NMR and MRI systems face challenges in obtaining spatially localized nuclear magnetic resonance parameters due to inadequate signal-to-noise ratio and insufficient scan time, especially in heterogeneous systems like the human body, where rectangular image voxels fail to accurately represent arbitrarily-shaped compartments of interest.
Innovation Solution
The method employs k-space spatial encoding gradients or coil sensitivity encoding maps to rapidly acquire and reconstruct NMR parameters in user-defined compartments, significantly reducing the number of phase-encoding steps and incorporating compartment segmentation information into standard Fourier reconstruction models, allowing for highly accelerated acquisitions and real-time measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional MRI is used to obtain spatially localized NMR parameters, then measurement precision is improved, but productivity deteriorates due to insufficient scan time and low signal-to-noise ratio
Solution Approach 1:
The patent divides the imaging space into user-defined compartments of interest rather than using a full-volume grid. By segmenting the first MRI image into compartments and only acquiring data for these specific regions, the method reduces the total number of phase-encoding steps required while maintaining precise spatial localization within each compartment.
Solution Approach 2:
The patent applies partial action by acquiring MRI data for only a subset of the full k-space corresponding to the compartments of interest, rather than imaging the entire volume. This partial acquisition strategy reduces scan time significantly while still providing accurate parametric information for the specific regions being studied.
2Adaptability or versatility
If rectangular image voxels are used in conventional MRI, then device complexity is reduced, but adaptability deteriorates because voxels cannot conform to arbitrarily-shaped compartments
Solution Approach 1:
The patent performs preliminary segmentation of the anatomy into user-defined compartments before the actual parametric imaging acquisition. This pre-segmentation step creates a mask or definition of the compartments of interest, which then guides the tailored MRI pulse sequence acquisition and subsequent reconstruction, allowing arbitrary compartment shapes without increasing hardware complexity.
3Productivity
If image voxel size is increased to cover desired volume, then productivity is improved, but measurement precision deteriorates due to overlap with other tissues
Solution Approach 1:
The patent applies local quality by using compartment-specific analysis where each voxel's signal is evaluated in the context of its specific compartment assignment. The reconstruction algorithm calculates compartment-specific parametric values by considering only the signal contributions from within each compartment boundary, thereby maintaining high measurement precision even when using larger effective coverage volumes.
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 enables rapid, high-sensitivity measurements of NMR parameters in arbitrarily-shaped compartments, achieving up to 120-fold acceleration and providing quantitatively equivalent results to conventional methods, facilitating real-time clinical applications.
Implementation Method 1
nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI)... using hydrogen (1H), carbon (13C), fluorine (19F), sodium (23Na) and phosphorus (31P) nuclei
Data Source
AI summary
An NMR method and system for acquiring and reconstructing a value of an NMR parameter spatially localized to a compartment of interest including performing a first MM of a portion of a sample with a first MRI pulse sequence using the NMR system and using a set of k-space spatial encoding gradients or coil sensitivity encoding maps to obtain a first magnetic resonance image to identify a compartment of interest; generating a second MRI pulse sequence that encodes the NMR parameter with a subset of the set of k-space spatial encoding gradients or the coil sensitivity encoding maps; applying the second MRI pulse sequence using the NMR system to acquire spatial information relating to the NMR parameter from the compartment of interest; segmenting the first magnetic resonance image into a plurality of compartments that includes the compartment of interest; and reconstructing a value of the NMR parameter in the compartment.