Low-Field MRI With Sparse Sampling to Reduce Imaging Artifacts

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Solution Overview

Problem

Existing magnetic resonance imaging (MRI) systems face challenges with high magnetic susceptibility and chemical shift artifacts, especially at high field strengths, leading to spatial distortions and decreased signal-to-noise ratios, which are exacerbated by parallel imaging techniques.

Innovation Solution

The implementation of a low field strength MRI system (less than 1.0 Tesla) utilizing sparse sampling techniques without parallel imaging, combined with low gradient fields, high flip angles, and controlled RF bandwidths, to minimize artifacts and maintain high spatial integrity and signal-to-noise ratio.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If high field strength MRI is used, then signal-to-noise ratio is improved, but magnetic susceptibility artifacts and chemical shift artifacts increase

Engineering Contradiction:
Improvesignal-to-noise ratioVSAvoidmagnetic susceptibility artifacts
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the operating field strength parameter from conventional high field (1.5T or 3T) to low field (0.35T), which fundamentally alters the artifact characteristics. At low field strength, the magnetic susceptibility artifacts and chemical shift artifacts are significantly reduced because these artifacts are directly proportional to the main field strength, while still achieving adequate signal-to-noise ratio through optimized pulse sequences and imaging parameters

Inventive Principle:
Principle #35Parameter changes

2Productivity

If parallel imaging techniques are used, then imaging speed is improved, but spatial distortions and artifacts are exacerbated

Engineering Contradiction:
Improveimaging speedVSAvoidspatial accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent extracts and removes the parallel imaging component from the imaging system, choosing to operate without it. This eliminates the spatial distortions and artifact exacerbation that come with parallel imaging techniques, while the imaging speed is maintained through optimized single-coil imaging sequences and low field strength advantages

Inventive Principle:
Principle #2Taking out (Extraction)

3Object-affected harmful factors

If low field strength is used, then artifacts are reduced, but signal-to-noise ratio decreases

Engineering Contradiction:
ImproveartifactsVSAvoidsignal-to-noise ratio
Core Design Contradiction:
Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The patent optimizes multiple imaging parameters specifically for low field operation, including using gradient-echo sequences with appropriate echo times, adjusting flip angles, and tuning bandwidth settings to maximize signal-to-noise ratio at 0.35T while maintaining the artifact reduction benefits of low field strength

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite approach combining low field strength magnet (0.35T) with optimized gradient systems and RF coil configurations, creating a hybrid system that achieves both artifact reduction and adequate signal-to-noise ratio through the synergistic combination of these components

Inventive Principle:
Principle #40Composite materials

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 achieves high-quality MRI with reduced distortions, enabling high frame rate cine imaging and real-time diagnostic and interventional applications, while minimizing patient heating and radiation exposure.

Implementation Method 1

a low field strength main magnet

Methodology Applied
Scientific EffectMagnetic field generation: Electromagnet

Implementation Method 2

a strong magnetic field (modified with weak gradient fields applied across it to localize and encode or decode phases and frequencies)

Methodology Applied
Scientific EffectMagnetic field gradient: Electromagnet

Implementation Method 3

Magnetic resonance imaging (MRI), or nuclear magnetic resonance imaging, is a noninvasive imaging technique that uses the interaction between radio frequency pulses, a strong magnetic field

Methodology Applied
Scientific EffectNuclear magnetic resonance: Magnetic Field

Data Source

PatentEP3475718B1Magnetic resonance imaging at low field strength
Publication Date: 2025.08.13 VIEWRAY SYSTEMS INC
  • EP3475718B1 patent drawingFigure 1
  • EP3475718B1 patent drawingFigure 2
  • EP3475718B1 patent drawingFigure 3

AI summary

Improved magnetic resonance imaging systems, methods and software are described including a low field strength main magnet, a gradient coil assembly, an RF coil system, and a control system configured for the acquisition and processing of magnetic resonance imaging data from a patient while utilizing a sparse sampling imaging technique.