MRI Sequence for Simultaneous Parameter Quantification
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Solution Overview
Problem
Current MRI methods face challenges in acquiring co-located images with the same spatial resolution for nuclear magnetization, longitudinal and transverse relaxation times, diffusion coefficient, and magnetic field inhomogeneities, leading to limitations in diagnosis due to spatial deformations and varying acquisition parameters across different sequences and manufacturers, making multi-center comparisons difficult.
Innovation Solution
A magnetic resonance imaging method involving repeated applications of a radiofrequency pulse and spatial magnetic field gradient with variable amplitude and phase, following a periodic sequence to achieve interleaved equilibrium states, allowing for simultaneous determination of nuclear magnetization, tilt angle, and relaxation times from the same point in space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple different MRI sequences are applied sequentially to quantify different physical parameters (nuclear magnetization, T1, T2, diffusion coefficient), then comprehensive tissue characterization is achieved, but spatial deformations and registration inaccuracies occur due to different acquisition parameters and timing
Solution Approach 1:
The patent combines multiple parameter quantifications (nuclear magnetization, T1, T2, diffusion coefficient) into a single unified MRI sequence rather than using separate sequential sequences. This merging approach ensures that all measurements are acquired simultaneously with identical spatial encoding parameters, eliminating the need for post-acquisition registration and avoiding spatial deformation mismatches between different parameter maps.
Solution Approach 2:
The patent creates a universal MRI sequence that performs multiple functions: it quantifies nuclear magnetization, T1 relaxation, T2 relaxation, and diffusion coefficient all within the same acquisition protocol. This multi-functional sequence uses a standardized readout with consistent spatial encoding that can extract multiple physiological parameters from a single data set, ensuring all parameters share the same spatial reference frame.
2Adaptability or versatility
If different manufacturers and centers use varying sequence configurations and parameters, then flexibility and adaptation to specific clinical needs are improved, but multi-center comparison and consensus establishment become difficult
Solution Approach 1:
The patent maintains flexibility by allowing adjustment of sequence parameters such as repetition time (TR), echo time (TE), and flip angle to optimize for different tissue types and clinical applications. However, it establishes a standardized core sequence structure and data processing pipeline that ensures measurements from different centers using the same protocol can be directly compared, achieving both adaptability and measurement consistency.
3Measurement precision
If sequential acquisition of different imaging sequences is used, then each sequence can be optimized for its specific purpose, but acquisition time and configuration complexity increase
Solution Approach 1:
The patent merges multiple parameter acquisitions into a single unified sequence that simultaneously measures nuclear magnetization, T1, T2, and diffusion coefficient. By acquiring all parameters in one continuous sequence with consistent spatial encoding, the total acquisition time is significantly reduced compared to running separate sequences, while maintaining the ability to precisely quantify each parameter through dedicated analysis of the combined data set.
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 precise quantification of physical parameters and standardization of imaging results, improving diagnostic reliability and facilitating multi-center consensus by acquiring nuclear magnetic resonance signals at different dynamic equilibrium states, thereby reducing spatial deformations and enhancing image registration.
Implementation Method 1
application of a main magnetic field B0 along an axis Z on a sample area
Implementation Method 2
a magnetic resonance imaging method involving repeated applications of a radiofrequency pulse and spatial magnetic field gradient
Implementation Method 3
after the radiofrequency pulse of the sequence, a spatial gradient of the component along the Z axis of the magnetic field
Implementation Method 4
determination of several data among a nuclear magnetization, a tilt angle of the magnetization, a diffusion coefficient, a longitudinal relaxation rate or time R1 or T1
Implementation Method 5
a transverse relaxation rate or time R2 or T2
Data Source
Figure 1~10
Figure 2a~3f
Figure 4a~4d
AI summary
The present invention relates to a MRI device (1) comprising: means (2) for applying a main magnetic field B0 on an axis Z over a sample zone (8); means (3) for emitting a magnetic field gradient and means (4) for emitting a radiofrequency pulse, and control means (5) arranged so as to control the means for emitting a magnetic field gradient and the means for emitting a radiofrequency pulse. The control means are programmed to carry out at least one set of repeated applications, on the sample zone, of a sequence comprising: a radiofrequency pulse possibly of variable amplitude and/or phase at each repetition; and after the radio frequency pulse, a spatial gradient of the component along the Z axis of the magnetic field. The control means are programmed so that, in the course of repeated applications of the radiofrequency pulse and of the magnetic field spatial gradient of the sequence of one and the same set: the radio frequency pulse follows, between its various repeated applications, a periodic series (preferably non-constant) for its amplitude and for a series un +l =vn +l -vn ; and each repeated application of the spatial gradient of magnetic field of the sequence a, according to a so-called coding spatial direction, a non zero timing integral equal to A and identical for each application of gradient of this set. The invention also relates to the method implemented by this device.