Nested Magnetic Noise Compensation Loops for MRI Field Homogeneity

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Solution Overview

Problem

Current methods for compensating magnetic noise fields in MRI apparatuses are inadequate in managing rapid and periodic disturbances, amplitude modulations, and high-intensity noise fields, particularly those above 10mGpp, and struggle with maintaining field homogeneity.

Innovation Solution

A system employing two nested compensation loops, one closed and one open, measures magnetic noise field characteristics outside and inside the spatial volume to generate precise compensation fields, using a combination of theoretical and empirical calculations to neutralize noise fields, with additional adjustments based on phantom responses for improved accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single compensation loop is used, then the device complexity is reduced, but the ability to manage rapid and periodic disturbances and maintain field homogeneity deteriorates

Engineering Contradiction:

Improvecompensation loop structureVSAvoidfield homogeneity

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The compensation system is divided into two independent nested loops: an inner loop for rapid disturbances and an outer loop for periodic disturbances. Each loop has its own sensors, controllers, and compensation coils, allowing simultaneous independent operation to address different noise characteristics without interference

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The compensation loops are nested within each other, with the inner compensation loop positioned inside the outer compensation loop. The inner loop compensates for rapid disturbances first, and the outer loop subsequently compensates for periodic disturbances, creating a hierarchical compensation structure that handles multiple noise types effectively

Inventive Principle:

Principle #7Nested doll (Nesting)

2Object-affected harmful factors

If high-intensity noise fields above 10mGpp are compensated, then the noise reduction capability is improved, but the device complexity increases due to additional adjustments and calculations

Engineering Contradiction:

Improvenoise field intensityVSAvoidcompensation system structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The system dynamically adjusts compensation parameters including current amplitude, frequency, and phase based on the measured noise field characteristics. For high-intensity noise fields above 10mGpp, the system modifies these parameters in real-time to maintain effective compensation while adapting to varying noise conditions

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The compensation system transitions from static to dynamic operation, continuously measuring noise field parameters and adjusting compensation coil currents accordingly. This dynamic adaptation allows the system to handle high-intensity and varying noise fields effectively without requiring overly complex fixed-structure designs

Inventive Principle:

Principle #15Dynamics

3Speed

If rapid disturbances are compensated, then the response speed is improved, but the ability to compensate periodic disturbances with amplitude modulations deteriorates

Engineering Contradiction:

Improvedisturbance response speedVSAvoidnoise type coverage

Core Design Contradiction:

SpeedVSAdaptability or versatility

Solution Approach 1:

The compensation system segments different disturbance types into separate processing channels: the inner loop handles rapid disturbances with high response speed, while the outer loop handles periodic disturbances with amplitude modulations. This segmentation allows each loop to be optimized for its specific disturbance type without compromising the other

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The nested loop structure acts as an intermediary mechanism where the inner loop first addresses rapid disturbances, and the outer loop subsequently addresses periodic disturbances. This intermediary arrangement allows both disturbance types to be compensated in sequence without direct interference between their compensation mechanisms

Inventive Principle:

Principle #24Intermediary (Mediator)

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 system effectively compensates for a wide range of magnetic noise fields, including high-intensity and periodic interferences, maintaining field homogeneity and reducing noise to near zero within the MRI imaging volume.

Implementation Method 1

a magnetic field compensator generating a compensation magnetic field inside the spatial volume

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3276366B1Method and system for compensating magnetic noise caused by environmental noise in a spatial volume

Publication Date: 2024.08.28 ESAOTE

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AI summary

A method for compensating magnetic noise in a spatial volume in which two concurrently operating compensation loops are provided comprising: a closed compensation loop for magnetic noise fields outside the spatial volume and inside the electromagnetically environment; an open compensation loop for magnetic noise fields in the spatial volume; said two compensation loops generating each one a magnetic noise compensation field; said two compensation fields concurrently provide for compensation of the magnetic noise field in the spatial volume.