Brain Free Water Quantification Using MRF Proton Density Mapping
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Solution Overview
Problem
Conventional MRI methods lack the ability to accurately and efficiently quantify brain free water content, which is crucial for diagnosing and monitoring neurological diseases, due to limitations in speed, complexity, and precision.
Innovation Solution
A method using a magnetic resonance fingerprinting (MRF) sequence to acquire M0 and T1 signals, combined with a unified segmentation algorithm to estimate receive coil sensitivity, allowing for rapid and precise calculation of proton density and free water content based on cerebrospinal fluid reference values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional MRI methods are used to locate edema, then imaging capability is provided, but quantitative precision of free water content is insufficient
Solution Approach 1:
The patent combines M0 mapping and T1 mapping into a single unified quantitative measurement framework. By integrating multiple measurement components (M0, T1, and free water content calculation) into one coherent method, the patent achieves precise free water quantification without requiring separate complex imaging sequences, thus resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The patent transforms conventional qualitative MRI imaging into quantitative measurement by introducing specific parameters (M0 equilibrium magnetization and T1 longitudinal relaxation time). This parameter-based approach enables precise free water content calculation through mathematical relationships, moving from subjective visual assessment to objective numerical measurement while maintaining practical clinical feasibility.
2Measurement precision
If multiple sequences are combined to determine M0 with correction factors, then measurement precision is improved, but acquisition time increases
Solution Approach 1:
The patent merges M0 mapping and T1 mapping into a single integrated acquisition protocol. Instead of performing separate M0 measurements and separate T1 measurements with multiple correction factors, the unified method simultaneously obtains both parameters through a coordinated sequence, reducing total acquisition time while maintaining the precision benefits of multiple measurements.
Solution Approach 2:
The patent performs preliminary characterization of tissue properties through the unified M0-T1 mapping approach, establishing baseline quantitative values that can be used for free water content calculation. This preliminary quantitative characterization eliminates the need for repeated measurements and complex post-acquisition corrections, reducing overall time investment while preserving measurement precision.
3Productivity
If MRF sequence is used to acquire T1 and M0 images, then acquisition speed is improved, but direct free water content quantification is not achieved
Solution Approach 1:
The patent extends the MRF sequence application by continuously processing the acquired T1 and M0 images through a unified quantitative framework. Instead of stopping at image acquisition, the method continuously transforms the raw MRF data into quantitative free water content maps through integrated mathematical processing, maintaining the speed advantage of MRF while achieving the previously missing quantification capability.
Solution Approach 2:
The patent introduces a unified quantitative mapping framework as an intermediary between MRF image acquisition and free water content measurement. This intermediary processing layer transforms the indirect M0 and T1 images obtained from MRF into direct free water content quantification, bridging the gap between fast acquisition and precise measurement without sacrificing either property.
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
Enables quick and accurate quantification of brain free water content without the need for customized sequences or complex post-processing, enhancing clinical applicability for neurological disease monitoring.
Implementation Method 1
in response to an RF excitation field generated on the basis of a magnetic resonance fingerprinting sequence and applied to the brain
Data Source
AI summary
In a method for measuring brain free water content, in response to an RF excitation field generated on the basis of a magnetic resonance fingerprinting sequence and applied to the brain, an equilibrium magnetization mixed term (M0) signal is acquired from radiation emitted by each excited voxel of the brain, to obtain an M0 value of each voxel of the brain; a receive coil sensitivity (RP) value of each voxel of the brain is acquired; the M0 value of each voxel of the brain is divided by the RP value of the corresponding voxel to obtain a proton density (PD) value of each voxel of the brain; a PD value of cerebrospinal fluid is taken to be a reference PD value; and the PD value of each voxel of the brain is divided by the reference PD value to obtain the free water content of each voxel of the brain. The method advantageously increases the speed and accuracy of measurement of brain free water content.