Phased Array RF Coil with Constant X-Ray Attenuation

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Solution Overview

Problem

Conventional MRI RF coils interfere with X-Ray imaging by causing artifacts or being visible in the image, necessitating their removal from the radiation path, which degrades MRI performance or introduces coil artifacts, complicating dual imaging systems.

Innovation Solution

A phased array RF coil design with conductive traces and a non-conductive support structure, where overlapping coil loops and support sections are optimized to maintain constant attenuation of penetrating radiation, ensuring the coil is invisible in X-Ray images without degrading MRI quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional surface MRI Receive Coil is placed in the imaging path of X-Ray system, then MRI image quality is maximized, but the coil becomes visible in the image and causes artifacts

Engineering Contradiction:
ImproveMRI image qualityVSAvoidcoil artifacts
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent changes the material parameter of the coil from conventional copper to aluminum, which has different X-ray attenuation properties. This material substitution reduces the coil's visibility and artifact generation in X-ray images while maintaining its functionality for MRI imaging

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite structure combining aluminum conductive traces with a non-conductive support board material. This composite design allows the coil to maintain electrical conductivity for MRI functions while the support board material provides X-ray transparency, reducing artifacts in radiation images

Inventive Principle:
Principle #40Composite materials

2Object-generated harmful factors

If RF coils are disposed out of or removed from the radiation path, then coil artifacts are eliminated, but MRI performance is degraded

Engineering Contradiction:
Improvecoil artifactsVSAvoidMRI performance
Core Design Contradiction:
Object-generated harmful factorsVSMeasurement precision

Solution Approach 1:

By changing the material composition and thickness parameters of the coil structure, the patent achieves a configuration where the coil remains in the radiation path but does not produce visible artifacts, eliminating the need to remove it while maintaining MRI performance

Inventive Principle:
Principle #35Parameter changes

3Object-generated harmful factors

If aluminum is used for RF coil traces to render them transparent to X-Ray, then coil visibility is reduced, but MR imaging performance degrades relative to copper

Engineering Contradiction:
Improvecoil visibilityVSAvoidMR imaging performance
Core Design Contradiction:
Object-generated harmful factorsVSMeasurement precision

Solution Approach 1:

The patent combines aluminum traces with a non-conductive support board material to create a composite coil structure. This composite design compensates for the lower performance of aluminum by optimizing the overall structure, achieving both X-ray transparency and acceptable MRI performance

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes the thickness parameter of the aluminum traces and support board to achieve the desired balance between X-ray transparency and electrical conductivity for MRI functions

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

The phased array RF coil allows simultaneous MRI and X-Ray imaging without artifacts, maintaining consistent radiation attenuation across the field of view, thus avoiding interference and enhancing image quality.

Implementation Method 1

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

Methodology Applied
Scientific EffectRadiation attenuation: Absorption (EM radiation)

Implementation Method 2

a phased array RF coil formed of a series of separate coil elements or individual loops for use in magnetic resonance imaging

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2523011B1Phased array MR RF coil which is not visible in X-ray image
Publication Date: 2017.04.19 IMRIS INC(CA)
  • EP2523011B1 patent drawingFigure 1
  • EP2523011B1 patent drawingFigure 2
  • EP2523011B1 patent drawingFigure 3

AI summary

An phased array RF coil (32) 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 (33) on which copper or aluminum conductive traces are carried. The attenuation of the X-Rays caused by the traces (36) is visible in the radiation image but this is compensated by arranging the non-conductive material of the support board such that the attenuation is substantially constant. The phased array includes individual coil loops which are overlapped with the traces (36) being of half thickness at crossing locations of the traces and with one of the loops (61,62) on one side and the other loop on the second side of the substrate sheet.