MRI Gradient Field Rephasing for Artifact Reduction

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Solution Overview

Problem

The existing MRI apparatuses face limitations in setting imaging parameters due to the increased load on hardware and objects caused by higher-order rephasing gradient magnetic fields, making it difficult to achieve desired imaging conditions.

Innovation Solution

An MRI system that calculates and applies a rephasing gradient magnetic field of a smaller amount than the predetermined order based on input imaging parameters, allowing for reduced hardware and object load while maintaining the rephasing effect, by using a gradient magnetic field generator, arithmetic processing unit, and measurement control unit to measure echo signals with a lower-order rephasing gradient magnetic field.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a higher-order rephasing gradient magnetic field is applied to eliminate artifacts caused by movement or flow, then the rephasing effect is improved, but the load on the hardware of the MRI apparatus and the object increases

Engineering Contradiction:

Improverephasing effectVSAvoidload on hardware and object

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies a rephasing gradient magnetic field of a smaller amount (lower order) than the predetermined order to achieve partial rephasing effect. This reduces the load on hardware and object while still eliminating artifacts caused by movement or flow, as evidenced by the calculation of rephasing gradient magnetic fields with reduced application strength or lower temporal order

Inventive Principle:

Principle #16Partial or excessive action

2Manufacturing precision

If a higher-order rephasing gradient magnetic field is applied to eliminate artifacts, then the image quality is improved, but the imaging parameter setting flexibility is reduced

Engineering Contradiction:

Improveimage qualityVSAvoidimaging parameter setting flexibility

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent changes the parameters of the rephasing gradient magnetic field by calculating and applying fields of smaller amount than predetermined order. This allows imaging parameters to be set according to operator preferences while maintaining artifact elimination capability, as the system can adjust the order and strength of rephasing gradients based on specific imaging conditions

Inventive Principle:

Principle #35Parameter changes

3Reliability

If a rephasing gradient magnetic field of predetermined order is applied, then the rephasing effect is maximized, but the hardware load increases making desired imaging conditions difficult to achieve

Engineering Contradiction:

Improverephasing effectVSAvoidimaging condition achievement

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent applies rephasing gradient magnetic fields of smaller amount (lower order) than the predetermined order, achieving sufficient rephasing effect for eliminating movement artifacts without maximizing the effect. This partial action reduces hardware load and enables desired imaging conditions to be achieved, as shown in the calculation methods that reduce gradient strength or temporal order

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS8981775B2Magnetic resonance imaging apparatus and gradient magnetic field application method

Publication Date: 2015.03.17 FUJIFILM CORP

AI summary

When it is difficult to apply a rephasing gradient magnetic field of a predetermined order according to an imaging parameter value set as input, a rephasing gradient magnetic field of a smaller amount of application is calculated, and at least some echo signals are measured using the calculated rephasing gradient magnetic field of the smaller amount of application.