T2 Preparatory RF Pulse Sequences for MRI Inhomogeneity Robustness

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Solution Overview

Problem

Magnetic resonance imaging (MRI) systems face challenges in producing robust T2 contrast preparatory pulses that are susceptible to magnetic field inhomogeneity and other imperfections, leading to undesired artifacts in images.

Innovation Solution

A method and system that simulate the magnetization state of a subject based on material parameters and magnetic fields, assess the quality of candidate RF pulses, and iteratively update them to meet a target T2 relaxation contrast, optimizing the pulse sequence to be robust against magnetic field inhomogeneity and other imperfections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If non-selective block pulses are used for T2 preparation, then the pulse sequence is simple to implement, but the image quality deteriorates due to susceptibility to magnetic field inhomogeneity and artifacts

Engineering Contradiction:

Improveease of implementationVSAvoidrobustness to magnetic field inhomogeneity

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent divides the T2 preparation pulse sequence into multiple segments including non-selective inversion pulses followed by selective refocusing pulses. This segmentation allows each pulse to be optimized for specific functions, improving overall robustness to magnetic field inhomogeneity while maintaining implementation feasibility.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent optimizes multiple parameters of the preparatory pulses including flip angles, timing delays, and pulse durations to achieve robust T2 contrast preparation. By systematically adjusting these parameters, the pulse sequence becomes less sensitive to magnetic field inhomogeneity while maintaining diagnostic image quality.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If conventional T2 preparatory pulses are used, then the imaging process is fast, but the contrast quality deteriorates due to artifacts from magnetic field imperfections

Engineering Contradiction:

Improveimaging speedVSAvoidcontrast quality

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies preparatory pulses before the main imaging sequence to pre-condition the magnetization state. This preliminary action ensures that T2 contrast is established before data acquisition begins, maintaining fast imaging speeds while improving contrast quality by pre-compensating for magnetic field imperfections.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent employs iterative optimization where the pulse sequence parameters are refined based on simulated or measured performance. This feedback mechanism allows the system to automatically adjust pulse parameters to achieve optimal contrast quality while maintaining efficient imaging timing.

Inventive Principle:

Principle #23Feedback

3Ease of operation

If simple RF pulse sequences are used, then the system operation is easy, but the diagnostic power deteriorates due to inability to optimize T2 contrast and robustness simultaneously

Engineering Contradiction:

Improvesystem operation simplicityVSAvoiddiagnostic power

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent designs a universal T2 preparation pulse sequence that simultaneously achieves multiple functions: T2 contrast enhancement, robustness to magnetic field inhomogeneity, and flow/motion compensation. This multi-functional approach maintains operational simplicity while significantly improving diagnostic power through optimized contrast and reduced artifacts.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 solution enhances image quality by producing T2 preparatory RF pulse sequences that are robust to magnetic field inhomogeneity and other imperfections, improving the diagnostic power of MRI systems by reducing artifacts and optimizing contrast.

Implementation Method 1

A T2 preparation pulse may be applied to a subject to drive a magnetization state of the subject to a target state. The T2 preparation pulse may be used to enhance a T2 relaxation contrast.

Methodology Applied

Scientific EffectT2 relaxation:

Implementation Method 2

an MRI image of a subject (e.g., a patient) is produced by measuring properties of the gyromagnetic materials of the subject, such as hydrogen nuclei. These properties are usually obtained by measurement of emissions of the gyromagnetic materials as a response to an excitation from an application of magnetic fields.

Methodology Applied

Scientific EffectMagnetic resonance:

Implementation Method 3

These properties are usually obtained by measurement of emissions of the gyromagnetic materials as a response to an excitation from an application of magnetic fields.

Methodology Applied

Scientific EffectGyromagnetic precession:

Data Source

PatentUS10094899B2Magnetic resonance T2 preparatory pulses for magnetic field inhomogeneity robustness and contrast optimization

Publication Date: 2018.10.09 GE PRECISION HEALTHCARE LLC

AI summary

Methods and systems to obtain and apply T2 preparatory radiofrequency (RF) pulse sequences for magnetic resonance imaging (MRI) are provided. The iterative methods may employ propagation of the magnetization state of the object being imaged and a comparison with a target magnetization state. The methods disclosed may be used to obtain MRI pulse sequences that may optimize T2 relaxation contrast. The produced RF pulse sequences may be robust to effects from inhomogeneity of the magnetic fields or other environmental or physiological perturbations.