RF Coil for MR Imaging with Uniform X-Ray Attenuation

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Solution Overview

Problem

Conventional MRI RF coils interfere with X-Ray images when used in dual imaging systems, requiring them to be removed or placed outside the radiation path, which degrades MRI performance or introduces artifacts, and existing solutions like using aluminum for transmissive coil sections compromise MR imaging quality.

Innovation Solution

An RF coil design with a support board and conductive traces that maintain constant attenuation of penetrating electromagnetic radiation throughout the field of view, using materials like copper and non-conductive materials with varying thicknesses to ensure uniform attenuation and minimize artifacts, with components like capacitors and fuses integrated to match the attenuation of conductive traces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional copper RF coils are used in dual imaging systems, then MRI imaging quality is maintained, but the coils become visible in X-Ray images and introduce artifacts

Engineering Contradiction:
ImproveMRI imaging qualityVSAvoidvisible artifacts in X-Ray image
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent changes the material parameter of the RF coil from conventional copper to aluminum, which has different X-ray attenuation properties. This material substitution makes the coil substantially transparent to X-ray radiation, eliminating visibility and artifacts in X-Ray images while maintaining MRI functionality

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite structure combining aluminum conductive traces with a non-conductive support board material. This composite design achieves the desired X-ray transparency while providing structural support and electrical conductivity for MRI operations

Inventive Principle:
Principle #40Composite materials

2Object-generated harmful factors

If aluminum RF coils are used to make the coil transparent to X-Ray, then artifacts in X-Ray images are reduced, but MR imaging performance degrades

Engineering Contradiction:
Improveartifacts in X-Ray imageVSAvoidMR imaging quality
Core Design Contradiction:
Object-generated harmful factorsVSMeasurement precision

Solution Approach 1:

The patent applies local quality by using aluminum specifically for the conductive traces that need to be transparent to X-rays, while the support board material provides structural support. This localized application of aluminum maintains MRI performance by preserving the necessary electrical properties for RF coil operation while achieving X-ray transparency

Inventive Principle:
Principle #3Local quality

3Object-generated harmful factors

If RF coils are placed outside the radiation path to avoid visibility, then X-Ray image quality is maintained, but MRI performance is degraded

Engineering Contradiction:
Improvevisibility of coil in X-Ray imageVSAvoidMRI imaging quality
Core Design Contradiction:
Object-generated harmful factorsVSMeasurement precision

Solution Approach 1:

The patent introduces an intermediary solution by using aluminum material as a mediator between the RF coil functionality and X-ray transparency requirements. The aluminum traces act as an intermediary that allows the coil to remain in the radiation path while being transparent to X-rays, eliminating the need to move the coil outside the field of view

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

Enables the RF coil to remain in the field of view during X-Ray imaging without introducing visible artifacts, maintaining consistent image quality and allowing for simultaneous MRI and X-Ray imaging without compromising either modality.

Implementation Method 1

the support board is formed from a non-conductive material in the field of view which has a thickness T1 at locations on the board spaced from the traces selected such that an attenuation of the penetrating electromagnetic radiation at those locations is substantially equal to the attenuation at the conductive traces

Methodology Applied
Scientific EffectX-ray attenuation: Absorption (EM radiation)

Implementation Method 2

an attenuation of the penetrating electromagnetic radiation of substantially the whole of the RF coil located within the field of view is substantially constant throughout the field of view

Methodology Applied
Scientific EffectElectromagnetic radiation transmission: Absorption (EM radiation)

Data Source

PatentEP2448479B1RF coil for mr imaging which is not visible in x-ray image
Publication Date: 2013.11.13 IMRIS INC(CA)
  • EP2448479B1 patent drawingFigure 1
  • EP2448479B1 patent drawingFigure 2
  • EP2448479B1 patent drawingFigure 3

AI summary

An RF coil used for MR imaging is designed so that it remains in place in the field of view of an X-Ray imaging system and comprises a support board on which copper conductive traces and copper printed capacitors are carried. The attenuation of the X-Rays caused by the copper traces is visible in the radiation image but this is compensated by arranging the non-conductive material of the support board such that the attenuation of substantially the whole of the RF coil located within the field of view is substantially constant throughout the field of view.