MRI Propeller Imaging Water-Fat Separation and Motion Correction

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Solution Overview

Problem

PROPELLER imaging in MRI systems faces challenges such as fat blurring due to chemical shift and main field inhomogeneity, which affect image quality and signal-to-noise ratio, and Dixon imaging methods can introduce additional scan time and data consistency issues.

Innovation Solution

A modified turbo-spin echo (TSE) sequence is used to acquire MR data within a single echo train at different echo shifts in an interleaved manner, simplifying phase correction and enhancing data consistency for improved water-fat separation and motion correction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If Dixon imaging is combined with PROPELLER imaging to cure fat blurring and main field inhomogeneity artefacts, then image quality is improved, but scan time is doubled and data consistency is compromised

Engineering Contradiction:

Improveimage qualityVSAvoidscan time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent segments the PROPELLER blade data acquisition into multiple echo trains, with each blade acquired in a separate echo train. This segmentation allows independent optimization of each blade's data acquisition parameters and enables parallel processing of multiple blades, thereby reducing total scan time while maintaining Dixon imaging capabilities for water-fat separation and artefact correction.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary phase correction using the first blade data before acquiring subsequent blade data. By pre-correcting the phase errors in the first blade and using this corrected data for motion estimation and phase correction of subsequent blades, the system avoids the need for re-acquisition and reduces overall scan time while maintaining image quality.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If PROPELLER imaging uses multiple echo trains for blade acquisition, then motion correction is improved, but data consistency between blades deteriorates

Engineering Contradiction:

Improvemotion correctionVSAvoiddata consistency

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses the first blade data to estimate motion parameters and phase errors, then feeds this information back to correct subsequent blade data. This feedback mechanism ensures that motion correction is applied consistently across all blades, maintaining data consistency while improving motion correction accuracy.

Inventive Principle:

Principle #23Feedback

3Manufacturing precision

If PROPELLER imaging acquires data with high readout bandwidth to reduce chemical shift artefacts, then water-fat separation is improved, but signal-to-noise ratio deteriorates

Engineering Contradiction:

Improvewater-fat separationVSAvoidsignal-to-noise ratio

Core Design Contradiction:

Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The patent optimizes the readout bandwidth parameter for each blade independently, adjusting it to balance chemical shift artefact reduction with signal-to-noise ratio preservation. By changing the readout bandwidth parameter adaptively across different blades and echo trains, the system achieves optimal water-fat separation while maintaining adequate signal quality.

Inventive Principle:

Principle #35Parameter changes

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 reduces artefacts, maintains water sharpness, and improves signal-to-noise ratio by simplifying phase correction and ensuring consistent data acquisition, thereby enhancing image quality and reducing scan time.

Implementation Method 1

a magnetic resonance (MR) imaging (MRI) system for reconstructing magnetic resonance (MR) images

Methodology Applied

Scientific EffectMagnetic resonance: Electromagnetic Induction

Implementation Method 2

Due to the difference in chemical shift between water and fat, the fat is shifted in a half or full circle

Methodology Applied

Scientific EffectChemical shift:

Data Source

PatentEP3114495B1MRI propeller with motion correction, water-fat separation and estimation of magnetic field inhomogeneity information

Publication Date: 2020.10.21 KONINKLIJKE PHILIPS NV

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AI summary

A magnetic resonance (MR) imaging (MRI) system, the MRI system may include at least one controller which may be configured to: acquire MR information for at least first and second blades of a periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) imaging method; generate, for at least the first and second blades, main field inhomogeneity information based upon the acquired MR information, the main field inhomogeneity information indicating main field inhomogeneity; generate water and fat information individually for at least the first and second blades based upon the acquired MR information and the generated main field inhomogeneity information for the corresponding blade of the first and second blades; and correct at least one of the water and fat information for spatial distortions caused by the main field inhomogeneity or a predetermined chemical shift difference between water and fat.